tutorial aspen hysys

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Chemical Process Simulation and

the AspenTech HYSYS Software

Version 2006

by

Michael E. Hanyak, Jr.Chemical Engineering Department

Bucknell UniversityLewisburg, PA 17837

authorized by

Thomas P. Rich, DirectorProcess Development Division

BEEF, Inc.

December 15, 2007



Copyright © 1998-2007 by Chemical Engineering Department

Printed in the United States of America

All rights reserved. No part of this report may be reproduced ortransmitted in any form or by any means, electronic or mechanical,including photocopying, recording, or any information storage andretrieval system, without permission in writing from the Publisher.

Chemical Engineering DepartmentBucknell UniversityLewisburg, PA 17837

Acknowledgement

I would like to thank the General Electric Fund for sponsoring, under its

Faculty for the Future program in the area of undergraduate research, thedevelopment of this problem-based learning material on computer-aidedchemical process simulation. Also, I further thank the American Institute ofChemical Engineers (AIChE) for their permission to use the material from their

1985 Student Contest Problem — Styrene from Toluene and Methanol inAppendix A of this workbook. The cost for this workbook includes twodollars that is paid to the AIChE for the use of their copyrighted material inAppendix A.

Jessica Keith (Class of 1998) and Cynthia Caputo (Class of 1999), undergraduatestudents in chemical engineering, deserve special thanks for their contributionsto this courseware development project during 1998 and 1999. Jessica provided initial drafts of Chapters 2, 3, and 4. She also wrote the first draft ofthe appendices on process simulation modules. Cynthia worked on enhancingthe process simulation modules using the MathType software, a mathematicalequation editor.

Finally, the sophomore students in my introductory course on chemicalengineering used drafts of this workbook during 1998 and 1999. I greatlyappreciate their feedback.

M. E. Hanyak

ii



Table of Contents

1. Introduction................................................................................................................ 1-1

2. HYSYS Simulation Tutorials

Overview ............................................................................................................. 2-1

2.1 Tutorial Conventions ......................................................................................... 2-2

A. Keywords for mouse actions............................................................................. 2-2

B. Text formatting .............................................................................................. 2-2

C. Interactive process modeling ............................................................................ 2-3

D. HYSYS at Bucknell University ......................................................................... 2-4

2.2 Introduction to the HYSYS Interface .............................................................. 2-7

A. Start the HYSYS program............................................................................... 2-7

B. Open a pre-defined simulation file .................................................................... 2-8

C. Manipulate stream specifications ...................................................................... 2-9

D. Change global preferences ............................................................................. 2-10E. Add variables to the workbook ....................................................................... 2-11

F. Alter the fluid package................................................................................... 2-12

G. Close the simulation case ............................................................................... 2-13

2.3 Simulation File Creation ................................................................................. 2-14

A. Start the HYSYS program............................................................................. 2-14

B. Build a fluid package .................................................................................... 2-14

C. Find component physical properties................................................................ 2-16

D. Create a process stream................................................................................. 2-17

E. Copy and delete a process stream.................................................................... 2-19

F. Save the simulation ....................................................................................... 2-20

2.4 Heater and Case Study .................................................................................... 2-22


B. Open an existing simulation file ..................................................................... 2-23

C. Add a heater operation.................................................................................. 2-24

D. Specify the heater outlet condition .................................................................. 2-26

E. Perform a case study ..................................................................................... 2-27

F. Close the simulation case................................................................................ 2-30

2.5 HYSYS Printing Capabilities ......................................................................... 2-31



C. Print the PFD and an active window ............................................................... 2-32

D. Print the heater datasheets............................................................................. 2-34

E. Print the case study plot................................................................................. 2-35

F. Create a report ............................................................................................. 2-35


iii



2.6 Conversion Reactor and Reactions ................................................................ 2-37



C. Add a reaction to the fluid package ................................................................. 2-39

D. Add a reactor to the flowsheet........................................................................ 2-42

E. Specify the reactor outlet conditions................................................................ 2-44


2.7 Gibbs Equilibrium Reactor ............................................................................ 2-47



C. Copy a reactor feed stream ............................................................................ 2-49

D. Add a Gibbs reactor to the flowsheet............................................................... 2-50

E. Specify the reactor outlet conditions................................................................ 2-52


2.8 Kinetic Model and a Plug Flow Reactor ........................................................ 2-57



C. Copy a reactor feed stream ............................................................................ 2-59

D. Add a plug flow reactor to the flowsheet.......................................................... 2-60

E. Add a kinetic reaction set to the fluid package.................................................. 2-62

F. Specify reactor parameters and outlet conditions .............................................. 2-66


2.9 PFD Manipulation Tools ................................................................................. 2-71

A. Start the HYSYS program.............................................................................

2-71


C. Zoom flowsheet in and out ............................................................................. 2-73

D. Orient some PFD icons .................................................................................. 2-74

E. Move some icon labels ................................................................................... 2-75

F. View some operating conditions...................................................................... 2-76

G. Add some documentation text ........................................................................ 2-77

H. Connect and disconnect PFD objects............................................................... 2-79

I. Copy a PFD to a Word document.................................................................... 2-85

J. Close the simulation case ................................................................................ 2-87

3. Process Unit Assignments

Overview .......................................................................................................... 3-1

HY.1 Process Stream Simulation ............................................................................ 3-2

HY.2 Pump Simulation............................................................................................. 3-4

HY.3 Cooler Simulation ........................................................................................... 3-6

HY.4 Mixer/Tee Simulation ..................................................................................... 3-9

iv



HY.5 Reactor Simulation ....................................................................................... 3-13

4. Flowsheet Development Assignments

Overview .......................................................................................................... 4-1

SM.1 Styrene Monomer Reaction Section.............................................................. 4-2

SM.2 Reactor Effluent Cooling/Decanting Section................................................ 4-3

SM.3 Methanol Recycle Purification Section ......................................................... 4-5

SM.4 Toluene Recycle Purification Section............................................................ 4-9

SM.5 Toluene/Methanol Feed Preparation Section............................................. 4-12

SM.6 Recycle Mixing and Preheating Section ..................................................... 4-13

SM.7 Styrene Monomer Purification Section ...................................................... 4-15

Appendix A. Styrene Monomer Production .............................................................. A-1

Introduction....................................................................................................... A-1

Proposed Styrene Process ................................................................................... A-1

Technical Data ................................................................................................... A-2

Design Data........................................................................................................ A-3

Economic Data ................................................................................................... A-6

Appendix B. HYSYS Simulation Modules................................................................. B-1

Appendix C. Process Stream Module ......................................................................... C-1

Appendix D. Mixer Module ......................................................................................... D-1

Appendix E. Pump Module .......................................................................................... E-1

Appendix F. Valve Module........................................................................................... F-1

Appendix G. Heater/Cooler Module ........................................................................... G-1

Appendix H. Chemical Reactor Module..................................................................... H-1

Appendix I. Two-Phase Separator Module ................................................................ I-1

Appendix J. Three-Phase Separator Module............................................................. J-1

Appendix K. Component Splitter Module ................................................................. K-1

Appendix L. Simple Distillation Module..................................................................... L-1

v



1. Introduction

Welcome to the Internship Program in the Process Engineering Department of BEEF,

Inc., the Bison Engineering and Evaluation Firm. As a new sophomore chemical engineer in this program, you will learn how to develop a chemical process and determine its processrequirements for material and energy using the process simulator HYSYS.

BEEF is a consultant company that solves chemical processing problems for

governmental institutions and industrial companies. Since our clients lack the technical expertise,they hire us to recommend and implement solutions to their chemical processing problems.Solving a client’s problem is a complex activity involving many departments in our company.Our department’s focus is to develop, on paper, a large-scale solution, called a process design, fora chemical-processing problem. We accomplish this design by synthesizing a process flowsheet,solving its material and energy balances, sizing and costing its equipment, and determining its profitability. Basically, we determine the feasibility of the process design, that is, is it feasible to build and run this process design. Finally, BEEF communicates a process design to our client inthe form of a technical report.

Hawbawg Chemical Company has hired us to investigate the feasibility of manufacturingstyrene monomer from the raw materials of toluene and methanol. Styrene monomer is an

intermediate material used to make such consumer plastic products as polystyrene packaging andfilm, cushioning materials, radio and television sets, and toys. As a first step in this feasibility

study, your team is assigned the tasks to develop the flowsheet and determine its process

requirements for material and energy that maximizes the net profit.

The chemical process for converting toluene and methanol to styrene monomer isglobally depicted in the diagram below. Appendix A provides substantial information on this process.

styrene monomer flowsheet

?

byproduct

wastes

toluene

methanol

You must synthesize the process flowsheet, where the chemical reactor is the heart of thatflowsheet. This flowsheet will be composed of process units (such as reactors, heaters, coolers, pumps,

and distillation columns) which are connected by process streams, and it will conceptually shows theflow of material and energy from the raw materials to the products. In developing this flowsheet,a process stream is assumed to have uniform temperature, pressure, flow rate, and composition(i.e., these variables do not vary along the length of the pipe). These four quantities are referred to as the

process state of a stream.

The development of any process flowsheet is a very complex activity. Engineers handlecom plexity by a divide and conquer strategy. In this handbook, Chapters 2, 3, and 4 are the sub- parts of a strategy to develop the flowsheet for the production of styrene monomer from tolueneand methanol. They accomplish the following:

• Chapter 2 introduces you to the HYSYS process simulation software. Thenine tutorials in this chapter provide you with detailed instructions on how to

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1. Introduction

use HYSYS in the Windows environment, in order to do some standard process simulation calculations.

• Chapter 3 provides five assignments in which you can develop your abilities

and confidence to simulate individual process units using HYSYS. Theseassignments focus on a process stream, pump, heater, mixer, tee, and reactor.

Once you’ve completed the assignments, you will have a mathematicalunderstanding of how HYSYS does its calculations for each process unit.

• Chapter 4 contains seven assignments to develop the styrene monomerflowsheet. Each member of your team will begin with the reactor section andincrease the complexity of the flowsheet by adding sections, one by one,until the complete flowsheet is simulated in HYSYS. While doing theseassignments, you will learn about heuristic rules that provide guidance onselecting process unit operations in the flowsheet and determining theiroperating conditions.

You will complete the tutorials of Chapter 2 and the assignments of Chapters 3 and 4 over a 14-

week period. Once these tasks are completed, you will have finished the first step in a feasibilitystudy on the production of styrene monomer from toluene and methanol; that is, the developmentof its flowsheet and processing requirements for material and energy.

While completing the tasks of Chapters 2, 3, and 4, you will need to access additionalinformation, which you can find in the appendices. Appendix A provides complete technical datafor the production of styrene monomer from toluene and methanol. You will use Appendix A tocomplete your assigned tasks in Chapter 4. Appendices B, C, etc. contain simulation modules forvarious process unit operations. Each appendix or module provides a mathematical explanationof how HYSYS does its calculations for that process unit. A module includes a description, aconceptual model, a mathematical model, example mathematical algorithms, and several HYSYSsimulation algorithms. You will need to consult these appendices while doing your assigned

tasks in Chapters 3 and 4.

As a new engineer in BEEF, Inc., your professional challenge of developing the styrenemonomer flowsheet using HYSYS is formable. To complete this challenge, you must developyour critical thinking skills as a problem solver. As reported by Diane F. Halpern in Thought and

Knowledge: An Introduction to Critical Thinking [1989, pp. 29-30], “No one can become a betterthinker just by reading a book. An essential component of critical thinking is developing theattitude of a critical thinker. Good thinkers are motivated and willing to exert the conscious effortneeded to work in a planful manner, to check for accuracy, to gather information, and to persist

when the solution isn’t obvious and/or requires several step.” … “Developing a critical thinking

attitude is as important as developing thinking skills. Many errors occur not because peoplecan’t think critically, but because they don’t. One of the major differences between good and

poor thinkers, and correspondingly between good and poor students, is their attitude.” In ourorganization, you must develop a critical thinking attitude; that is, you must be willing to plan, beflexible in your thinking, be persistent, and be willing to self-correct. You can not become acritical problem solver without this sort of attitude.

BEEF, Inc. hired you as a new employee, because you possess the talent to become acritical problem solver. What you must decide—“Does the degree of my desire match that of my

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1. Introduction

talent?” You must work hard, pay attention to detail, take pride in your work, and observe professional ethics, in order to become an effective engineer.

Welcome to our company, and good luck in your team's development of the styrenemonomer flowsheet. Remember our company motto, “Engineering is 10 percent inspiration and90 percent perspiration.”

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Overview

A fundamental aspect of chemical engineering is the design of chemical processes. Achemical process transforms raw materials into products through a series of process unitsconnected by process streams. A process unit or unit operation is equipment that physicallyand/or chemically changes the chemical compounds passing through it. Increasing temperature,decreasing pressure, and mixing are some examples of physical changes, while chemicalreactions cause changes in chemical compounds. Process units are connected by material processstreams that carry the chemical compounds at a certain process state—temperature, pressure, flowrate, and composition. Energy streams connected to process units supply the needed energy foran operation or remove energy released in an operation. A schematic diagram called a processflow diagram and often referred to as a flowsheet represents a chemical process. A flowsheetshows all process units and streams and how they are connected, as illustrated in Figure 2.1 below.

350°C

3025 kPa

350°C

3075 kPa

25°C

3095 kPa

330 kgmol/h

64.8% benzene33.5% propylene

1.7% propane

0.0% cumene

Q = ? Q = ?

E1heater

R1reactor

S1 S2 S3

Figure 2.1. A Simple Process Flowsheet

The arrow lines labeled S1, S2, and S3 are material streams, while the other two arrow lines are

energy streams. The two circles labeled E1 and R1 are process units. For the flowsheet in Figure2.1, the simulation problem is “what heat duty in kJ/h is required to raise the temperature of

stream S1 from 25 to 350°C” and “how much energy in kJ/h is required to operate the reactor atan isothermal condition (i.e., at constant temperature)”?

A simulation of a chemical process does the material and energy balances on all of the process units. This information can then be used to see how to manipulate the process tomaximize product, minimize energy use, etc. Aspen Tech’s HYSYS is a computer program thatsimulates chemical processes. Using a computer for a process simulation takes a fraction of thetime it takes to do it by hand. The speed of a computer simulation allows the user to observequickly the effect of changes in a simulation. For example, using HYSYS, you can easilycompare the amount of product produced using different ratios of starting materials. Doing thiscomparison with hand calculations would be a long and tedious task.

In this chapter, you will learn how to use HYSYS in Windows to do some processsimulation calculations. You will also gain a better understanding of some chemical process unitsand how their material and energy balances are solved. This chapter presents nine tutorials to

introduce you to steady-state process simulation. They are: (1) tutorial conventions, (2)introduction to the HYSYS interface, (3) simulation file creation, (4) heater and case study, (5)HYSYS printing capabilities, (6) conversion reactor and reactions, (7) Gibbs equilibrium reactor,(8) kinetic model in a plug flow reactor, and (9) process flow diagram (PFD) fundamentals.

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Tutorial 2.1

Tutorial Conventions

Since HYSYS is totally interactive, it provides virtually unlimited flexibility in solvingany simulation problem. Please keep in mind that the approach used in solving each example

problem presented in this tutorial chapter may only be one of many. You should feel free toexplore other alternatives by consulting the HYSYS Reference Manual.

This tutorial presents general convention adopted for this chapter. It focuses onterminology used to describe mouse actions and on formatting conventions for text in thischapter. Most of the conventions presented below have been taken directly from the HYSYS

Reference Manual. The tutorial also presents general comments on interactive process modeling,the HYSYS way. Finally, you initialize HYSYS for use at Bucknell University.

A. Keywords for mouse actions.

As you read through various procedures in this handout, you will be given instructions on performing specific functions or commands. Instead of repeating certain phrases for mouseinstructions, we will use a keyword to imply a longer instructional phrase:

•

The keywords select , choose, pick , press, or click mean to position the cursor onthe object or button of interest, and press the primary mouse button once.

•

The keyword double-click means to position the cursor on the object of interest,and press the primary mouse button twice quickly in succession.

•

The phrase click and drag means to position the cursor on the object of interest,

press and hold the primary mouse button, move the cursor to a new location, and

release the primary mouse button.

• The keyword object inspect means to position the cursor on the object of interest,and press the secondary mouse button once.

• The keyword enter means to position the cursor in an input cell, press the

primary mouse button once, type the required information, and then press the

<Enter> key on the keyboard.

For a standard two-button mouse, the primary mouse button is on the left, while the secondary one is on the right, provided you have not changed the mouse settings through Windows.

B. Text Formatting.

A number of text formatting conventions are also used throughout this chapter. Theyhelp to quickly identify menu commands, buttons, keys on the keyboard, windows or views, areaswithin windows, radio buttons and check boxes in window areas, material and energy streamnames, unit operation names, and HYSYS unit operation types. These conventions are asfollows:

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Tutorial 2.1

• When you are asked to invoke a HYSYS menu command, the command is

identified by bold lettering. For example, File indicates the File menu item,

while Tools/Preferences… means the Preferences option within the Tools menu.

•

When you are asked to press a HYSYS button, the button is identified by bold,italicized lettering. For example, Close identifies the Close button on a particularwindow (i.e., a view).

• When you are asked to press a key or keys to perform a certain function,keyboard commands are identified by bold lettering, enclosed by angle brackets.

For example, <F1> identifies the F1 key on the keyboard.

• The name of a HYSYS view (or window) is indicated by bold lettering; e.g.,

Session Preferences.

•

The name of a Group or Area within a view is identified by bold lettering; e.g.,Initial Build Home View.

• The name of Radio Buttons and Check Boxes are identified by bold lettering; e.g.

Workbook.

• Material and energy stream names are identified by bold lettering; e.g., S1,

Column Feed, and Condenser Duty.

•

Unit operation names are identified by bold lettering; e.g., Flash Separator or

Atmospheric Tower.

Note that blank spaces are acceptable in the names of streams and unitoperations.

•

HYSYS unit operation types are identified by bold, uppercase lettering; e.g.,

HEAT EXCHANGER, SEPARATOR, and DISTILLATION COLUMN.

• When you are asked to provide keyboard input, it will be indicated by bold

lettering; e.g., “Enter 100 for the stream temperature”.

Most of the above formatting conventions have been taken directly from the HYSYS Reference

Manual.

C. Interactive process modeling.

As stated in the HYSYS Reference Manual, the role of process simulation is to improveyour process understanding so that you can make the best process decision. Aspen Tech’sHYSYS solution has been, and continues to be, Interactive Simulation. This solution has notonly proven to make the most efficient use of your simulation time, but by building the model

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Tutorial 2.1

interactively—with immediate access to results—you gain the most complete understanding ofyour simulation.

The HYSYS software uses the power of Object-Oriented Design, together with an Event-Driven Graphical Environment, to deliver a completely interactive simulation environmentwhere:

• calculations begin automatically whenever you supply new information,and

• access to the information you need is in no way restricted.

At any time, even as calculations are proceeding, you can access information from any location inHYSYS. Each location is always instantly updated with the most current information, whetherspecified by you or calculated by HYSYS.

Given the power and flexibility designed into HYSYS, many ways exists to accomplishthe same task. The tutorials of this chapter have been designed to show you one way to do eachHYSYS task, primarily for simplicity and speed. Other ways do exist, and you can consult the

HYSYS Reference Manual to investigate those ways. This manual exists in paper and electronicforms. Your instructor will give you information on how to access the electronic version of the HYSYS Reference Manual using the Adobe Acrobat Reader program in Windows.

D. HYSYS at Bucknell University.

Before using the HYSYS software at Bucknell, you must create a HYSYS folder and then setsome of the HYSYS preferences. Proceed as follows:

•

First, you must create a folder in your private area on the network file server and nameit “hysys”. To create this folder:

1.

Log on to a computer that is connected to the network.

2. Double-Click the My Computer icon in the Desktop area.

3.

Double-Click the student server (U:) icon.

4. Double-Click your private folder.5. Click the secondary mouse button in your private folder and select

New/Folder.

6. Finally, name the new folder hysys.

•

Second, you must configure some preferences in the HYSYS software and save them in

your private hysys folder. To configure the HYSYS software, proceed as follows:

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Tutorial 2.1

1. C hoose Aspen HYSYS 2006 thru the Start/All

Programs menu on the Windows desktop.

Click the middle Maximize Window icon

in the upper-right part of the HYSYS desktop.

To access the HYSYS program from thenetwork file server.

To expand the HYSYS desktop window to fit

the full area of the monitor screen.

2. C hoose Tools /Preferences… from the menu

bar.

No te that

No te that

Select the Simulation/Options page, if

necessary.

Uncheck the Use Modal Property Views in

the General Options area, if necessary.

No te that

To display the Session Preferences window

with tabbed preference views.

Any window in HYSYS may have several tab

views, such as Simulation, Variables,

Reports, etc. in the Session Preferences

window. Within a tab view, several pagesmay exist as indicated by the selections in the

far-left area, such as Options, Desktop, etc.

in the Simulation view.

In this manual, we will use notation likeSimulation/Options to refer to a particular page in a particular view.

To make it the current preference page, which

you will alert.

To de-activate the modal mode of displaying property windows.

HYSYS will now display all windows as non-modal views, allowing you to conductactivities outside of any opened window.

3. Select the Variables/Units page.

Click SI in the Available Unit Sets area,if necessary.

To display the Units preference page in the

Variables view.

To instruct HYSYS to use the SI system of

units— °C, kPa, kgmole/h, kJ, etc.

4. Select the Reports/Company Info page.

Type CHEG 200, your name in the Company Name cell. E.G., CHEG 200, Michael Hanyak

Type the following in the Company Location

cell:Process Engineering Department

BEEF, Inc., A Consultant Company

Lewisburg, PA 17837

To display the company name and location.

To provide a unique identification of you.

To provide a unique identification for your

com pany.

This company name and location will besupplied on all HYSYS reports that you print.

5. Click the Save Preference Set … button, then

click the Save button in the current window.

To save your default preferences for theHYSYS program in your private HYSYS

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Tutorial 2.1

folder on the network file server.

6. Click the Close button; that is, the X button inthe upper right corner of the window.

To close the Session Preferences windowand return to the HYSYS desktop.

7. C hoose File/Exit from the menu bar

orPress keys <Alt><F4> on the keyboard.

To exit the HYSYS program.

You have saved all preferences contained in the Session Preferences window in your private

hysys folder. Whenever you start the HYSYS program, it will automatically read your saved preferences in order to set the HYSYS environment. You should get into the habit of checking

your preferences using the Tools/Preferences… menu, after the program has started.

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Tutorial 2.2

Introduction to the HYSYS Interface

To familiarize yourself with HYSYS, you will first open an existing file named intro.hsc

located on the network file server. This HYSYS file simulates a material stream containing

benzene, propylene, propane, and cumene. It also uses the Peng-Robinson-Stryjeck-Vera (PRSV)fluid package to calculate the thermodynamic properties of the stream. The conceptual diagram

for this stream is:

S1

T C

P kPa

n kgmol h

z

z

z

z

S

S

S

S BZ

S PY

S PR

S CU

1

1

1

1

1

1

1

25

175

200

0 500

0 015

0 015

0

=

=

=

=

=

=

=

/

.

.

.

.470

,

,

,

,

You will practice HYSYS navigation fundamentals and some basic HYSYS capabilities in seven

sections—start the HYSYS program, open a pre-defined simulation file, manipulate stream

specifications, change global preferences, add variables to the workbook, alter the fluid package,

and close the simulation case. To proceed, you must be familiar with the material in Tutorial 2.1.

A. Start the HYSYS program.

When you start the HYSYS program, it always begins with whatever global

preference settings were last saved in your default preference file. You should

always check these default preferences before you begin your simulation work.

Proceed as follows to check the system of units:

1. Choose Aspen HYSYS 2006 thru the Start/All




To access the HYSYS program from the

network file server.



2. Choose Tools/Preferences… from the menu

bar.




Click SI in the Available Unit Set area,

if necessary.


Variables view.



4. Click the Close button; that is, the X button in

the upper right corner of the window.

To close the Session Preferences window

and return to the HYSYS desktop.

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Tutorial 2.2

B. Open a pre-defined simulation file.

A HYSYS simulation file has been created and placed on the network file server

for you to access. It is called intro.hsc. This section explains how to locate and

open this existing simulation file, and then save the simulation to either your

personal folder or the Windows desktop. Proceed as follows:

1. Choose File/Open/Case from the menu bar,

or

Click the Open Case icon on the button bar.

To display the Open Simulation Case

window. You will access a pre-defined

HYSYS “.hsc” file from the network file

server, as directed by your instructor.

2. Look in the pull-down menu▼, select the

departments server (R:), and navigate to

folder chem_engineering/public/HYSYS

Manual/Chap 2.

To find the HYSYS simulation file intro.hsc

on the network file server in the HYSYS

Manual folder.

3. Double-click on the file named intro.hsc,or

Select this file and click the Open button.

To open the pre-defined simulation file. TheProcess Flow Diagram (PFD) window

appears in the HYSYS desktop.

4. Choose File/Save As… from the menu bar. To display the Save Simulation Case As

window. You are about to save this pre-

defined simulation case as a new simulation

case file in one of your personal folders.

5. Look in the pull-down menu▼, select your

student server (U:) icon, and navigate to your

private/hysys folder.

or

select the computer’s Desktop.

Note that

Click the Save button.

To store the simulation in your personal folder

as a file on the network file server. Your

instructor may give you directions.

To save the file on the Windows computer.Saving a file to the computer will result in

faster simulations, since HYSYS will not have

to transfer data over the network. Simulation

speed becomes important as your file becomes

larger.

After you have finished your simulation work,

you can drag the file from the Windows

desktop to your personal folder on the

network file server for permanent storage.

To save your intro.hsc simulation file.

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Tutorial 2.2

C. Manipulate stream specifications.

The existing HYSYS file intro.hsc simulates a material stream at a given

temperature, pressure, flow rate, and composition. These four quantities are

referred to as the process state of a stream. This section shows you how to

change a stream’s process state by altering its current temperature, pressure, and

composition. You will also learn how to change the stream’s state by specifying

the vapor fraction instead of the temperature. Proceed as follows:

1. Click the Workbook icon on the button bar. To access the Workbook window.

The Unit Ops page appears. This page is

empty because no unit operations are in the

Process Flow Diagram (PFD).

2. Click on the material Streams tab.

Note that

To display the material Streams page, which

currently shows the conditions of stream S1.

The Workbook window contains multiple

pages with tabs to move from one to another.

User-supplied values are shown in blue and

can be changed by you. Values calculated by

HYSYS are in black and cannot be changed.

3. Enter 80 in the Temperature cell of Stream S1;

i.e., click in cell, type a value, and hit the <Enter > key.

Note that

To change the temperature from 25 to 80°C.

Notice the Heat Flow value changes from

8.908e+5 to 2.766e+6 kJ/h

The black values of Vapor Fraction, Mass

Flow, Liquid Volume Flow, and Heat Floware recalculated automatically by HYSYS for

the new temperature.

4. Enter 3 bar in the Pressure cell of Stream S1.

or

Enter 3 and select the drop-down menu of ▼

at the far right and choose units bar.

To change the stream pressure from 175 to

300 kPa. HYSYS automatically converts the

pressure from bars to kPa and displays the

pressure in kPa.

5. Double-click in the Molar Flow cell containing

a value of 200.

Click on Mass Fractions in the Composition

Basis area.

Enter 1 in the Mass Fraction cell for benzene;

and do this task three more times, once for

each chemical component.

To open the property window called Input

Composition for Stream. This view displays

the chemical component mole fractions, as

indicated by the Composition Basis area.

To display the component mass fractions of

Stream S1.

To specify a stream with equal mass for each

chemical component; that is, four 1’s appear

in the MassFraction column.

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Tutorial 2.2

Click the Normalize button.

Click the OK button.

Note that

To have HYSYS sum mass fractions to 1.0

To change the stream’s composition and have

HYSYS calculate the new Vapor Fraction,

Mass Flow, Liquid Volume Flow, and Heat

Flow for stream S1. The vapor fraction forstream S1 is now non-zero, implying that two

phases (vapor-liquid) are coexisting together.

When doing calculations on a process stream,

you must enter values for its flow rate and

composition, as well as for only two of its

first three quantities—vapor fraction,

temperature, and pressure.

The vapor fraction can range from zero to

one. A value of zero implies a liquid phase,

while a value of one implies a vapor or gas

phase. A value between zero and one impliesa vapor-liquid phase.

6. Click in the Temperature cell and

then hit the <Delete> key.

Do not us the <Backspace> key for this task.

Enter 0 in the Vapor Fraction cell of stream S1.

Enter 1 in the Vapor Fraction cell of stream S1.

To delete the stream’s temperature value. The

temperature or pressure specification must be

deleted in order to specify the vapor fraction.

To calculate the bubble-point condition of the

stream; that is, its saturated-liquid state. The

bubble point of –8.074°C is when the first

bubble of vapor forms out of the liquid phase.

To calculate the dew-point condition of thestream; that is, its saturated-vapor state. The

dew point of 122.5°C is when the first drop of

liquid forms out of the vapor phase.

D. Change global preferences.

The preferences capability in HYSYS allows you optionally to set the units

system, deletion confirmation, modal property view, and automatic stream

naming. The simulation file intro.hsc currently contains your HYSYS default

preferences. In this section you will change the HYSYS modal view and unitssystem preferences. Proceed as follows:

1. Choose Tools/Preferences… from menu bar,

and select the Simulation/Options page.

Click Use Modal Property Views in the

General Options area to activate it.

To make it the current page in the Session

Preferences window that you will alert.

When any property view (i.e., window) is modal

you cannot access any other element in the

simulation. That is, you cannot select a menu

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Tutorial 2.2

Click Use Modal Property Views in the

General Options area again to de-activate it.

Note that

item or another view that is not directly part

of that modal view. A modal view has a pin

icon in the upper right corner next to the

icon. Clicking on that pin converts the modal

view to a non-modal view and allows you to

conduct activities outside of that view.

By de-activating the Model Property View

preference, you have instructed HYSYS to

display all views as non-modal.


Click Field in the Available Unit Sets area.

Click the Clone button to the right of the

Available Unit Sets area.

Type my-fps in the Unit Set Name cell.

Click in the Pressure cell with units of psia andselect unit atm from the drop-down menu of

▼.

Click the Close button.

To display the Units preference page.

To change from SI units to English units.

The simulation originally displayed SI units—

°C, kPa, kgmole/h, etc. The Field units will

display English units— °F, psia, lbmole/h, etc.

The individual property units within the SI,

Field, or EuroSI system unit sets can not bechanged. You must clone one of these three

sets to create your preferred units set.

To create a new unit set whose current name

is NewUser.

To given a unique name to this cloned Field

units set. The individual property units of

my-fps are the same as the Field units set.

However, in a cloned unit set, the individual

property units can be changed to suit you.

To change the pressure units from psia to atm.The drop-down is near the top of the window.

To return to the Workbook window and see

the new set of units for the process stream.

E. Add variables to the workbook.

The HYSYS workbook displays a summary of process unit operations and

streams. The value and units of chosen variables are displayed with each unitoperation or stream. This section shows you how to add additional variables on

the Streams page of the workbook. Proceed as follows:

1. Choose Workbook/Setup… from the menu

bar.

Click Streams in the Workbook Tabs area.

To open the Setup window and change the

organization of the workbook.

To modify the contents of the Streams page.

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Tutorial 2.2

Click the Add… button in the Variables area. To open the Select Variable(s) for Main

window.

2. Click Comp Mole Frac in the Variable area,

then click button All in the All/Single area.


To add all the component mole fractions to

the Streams page of the workbook.

To return to the Setup window.

3. Click the Close button in the Setup window. To return to the Workbook window. Now,

all stream component mole fractions appear in

the workbook. Variables can be deleted and

added to the workbook as desired.

F. Alter the fluid package.

The fluid package contains thermodynamic, component, and reaction informationfor the simulation. This section explains how this basis information in the fluid

package is altered in HYSYS. You will change the property package, view some

physical properties of a chemical component, and re-order the components in the

current fluid package. Proceed as follows:

1. Choose Simulation/Enter Basis Environment

or

Click on the Enter Basis Environment icon on

the button bar.

Click on the Fluid Pkgs tab, if necessary.

Click the View… button in the Current FluidPackages area.

If a warning window appears, click its OK

button only.

To open the Simulation Basis Manager

window. This is where basic information for

the simulation is entered, such as the thermo-

dynamic model and the chemical components.

To view the Fluid Packages page.

To enter the current Fluid Package: Basis-1 window.

To ignore a warning message concerning a

comsel index file.

2. Click on the Set Up tab, if necessary.

Scroll down and click on SRK in the Property

Package Selection area.


To view the Fluid Package/Set Up. The

current Property Package Selection is the

PRSV model.

To change the property package from PRSV

to SRK, the Soave-Redlich-Kwong model.

To return to Current Fluid Packages page.

3. Click on the Components tab.

Click the View… button.

To view the Component Lists. The Master

Component List should already be selected.

To view the chemical Component List View

page. The simulation compounds are listed in

the Selected Components area.

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Tutorial 2.2

Double-click Benzene in the Selected

Components area.

Click on the Critical tab.

Click on the Close button.

To view the Benzene window of physical

properties.

To view the base and critical properties of

benzene. Note its normal boiling point of

176.2°F. You can also view other physical properties through the other tab pages.

To return to the Component List View page.

4. Click the Sort List button to the right of the

Selected Components area.

Click benzene in Component(s) to Move area

Click cumene in the Insert Before area, and

Click the Move button.

Click propane in Component(s) to Move area

Click propene in the Insert Before area, and

Click the Move button.



To view the Move Components for Basis-1

Component List window. You will re-order

the components in order of increasing normal

boiling points.

To move benzene just before cumene, since

the normal boiling point of benzene is 176.2

°F compared to 306.3 °F for cumene.

To move propane just before propene, since

the normal boiling point of propane is –43.78

°F compared to –53.95 °F for propene.

To return to the Component List View page.

Note the new order of the chemical

components.

To return to the Simulation Basis Manager

window.

5. Click Return to Simulation Environment…

in the lower-right part of the window.

Click the No button in the question window.

To return to the process simulation which

contains the PFD and the workbook.

To have HYSYS directly do any calculations.

The workbook appears again, showing stream

S1 with the new ordering for the components.

G. Close the simulation case.

You will close the file containing your simulation case and then exit HYSYS. Proceed as

follows:

1. Choose File/Close Case from the menu bar,

then click the No button.

To close the current simulation file and

not save it.

2. Choose File/Exit from the menu bar

or

Press keys <Alt><F4> on the keyboard.

To exit the HYSYS program.

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Tutorial 2.3

Simulation File Creation

In Tutorial 2.2 for the “Introduction to the HYSYS Interface,” you practiced basic

HYSYS skills using an existing simulation file intro.hsc. Now you will learn how to create and

save a simulation file identical to intro.hsc. The creation of this file is divided into sixsections ⎯ start the HYSYS program, build a fluid package, find component physical properties,

create a process stream, copy and delete a process stream, and save the simulation. To proceed,

you must be familiar with the material in Tutorial 2.2.






Please note that you may be familiar with this procedure from previous tutorials.







To expand the HYSYS desktop window to fitthe full area of the monitor screen.

2. Choose Tools/Preferences… from the menu bar.

To display the Session Preferences windowwith tabbed preference views.



if necessary.


Variables view.





To close the Session Preferences window and

return to the HYSYS desktop.

B. Build a fluid package.

To simulate a process flowsheet in HYSYS, you must first create what is called a

Fluid Package. This package is where all the basic simulation information such

as chemical components, thermodynamic model, and chemical reactions are

stored. Proceed as follows:

1. Choose File/New/Case from the menu bar.

orClick the New Case icon on the button bar.


window and then start a new simulation case.In this window, the list of chemical can be

defined and a new Fluid Package can becreated.

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Tutorial 2.3

2. Click the Components tab, if necessary.

Note that

Click the View… button.

Note that

Click the cursor in the Match cell, if necessary.Type benzene in the Match cell.

Click the Add Pure button to the left.

Click the cursor in the Match cell.

Type propylene in the Match cell.Click the Add Pure button to the left.

Repeat above steps for propane and cumene.


To view the Components page. In this page,

the Component Lists area should have theMaster Component List highlighted.

In HYSYS, components are the chemical

compounds you will use in your simulation.

To view the Component List View page with

Traditional highlighted in the Add

Component area.

In this page, you will add the chemicalcompounds—benzene, propylene, propane,

and cumene—to your new simulation.

To position the vertical bar in that cell.

To get benzene selected in the scrolling area.

To add benzene to the Selected Components

area.

To select the current name in that cell.To get propene selected in the scrolling area.

To add propene to the Selected Components

area.

To add these final two compounds to the

Selected Components area.

To close the Component List View window

and return to the Components page.

3. Click the Fluid Pkgs tab.

Click the Add… button.

Note that

Click EOSs in the Property Package Filter area.

Click PRSV in the Property Package

Selection area.

To open the Fluid Pkgs page and begin the

process of creating a new Fluid Package.

To open the Fluid Package/Setup windowwith its Property Package Selection area.

A property package contains the basic

thermodynamic equations and relationships

used in property calculations for mixtures of

chemical compounds, called components.Some example calculations are the density,

enthalpy, and dew or bubble point temperature

of a mixture.

To display a list of the equation-of-state packages supported by HYSYS.

To select the Peng-Robinson-Stryjeck-Vera

equation of state as the property package.At this time, HYSYS loads the complete

physical property database for all the chemical

compounds you selected earlier.

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Tutorial 2.3

If a warning window appears, click its OK

button only.

Click the View… button in the ComponentList Selection area.

Click the cursor in the Name area at the bottom

of the page

Type PRSV Component List in the Namearea.


Click theClose

button.

To close a warning message concerning a

comsel index file. While loading the physical property database, HYSYS may issue this

warning message, which you can ignore.

To open the Component List View:Component List - 1 page.

To highlight its contents of “Component List -

1”. You are going to change this name.

To rename this component list, so that youwill know that it is always associated with the

PRSV equation of state.

To close the Component List View window

and return to the Fluid Package/Setup page.

To close the Fluid Package/Setup window

and return to the Fluid Pkgs page in the

Simulation Basis Manager window.

C. Find component physical properties.

The HYSYS property package contains physical property information for each

chemical compound. Some example physical properties are the molecular

weight, the critical temperature and pressure, and the Antoine coefficients. This

information can be viewed using the Components page of the Simulation Basis

Manager window. You will find the normal boiling point and the Antoine

coefficients for cumene. Proceed as follows:

1. Click the Components tab.

Click the PRSV Component List.Click the View… button.

Click the component named cumene

Click the View Component button.

orDouble-click on the component name.

To open the Components page in the

Simulation Basis Manager window.

To highlight it the Component Lists area.To view the list of chemical components

associated with the PRSV equation of state.

To select this compound in the Selected

Components area.

To open the Cumene component properties

window and view the ID or identification page.

2. Click on the Critical tab.

View the Normal Boiling Point.

To view the Critical Properties page. Here

the molecular weight, normal boiling point,

and saturated liquid density properties areshown under Base Properties.

To confirm that the normal boiling point of

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Tutorial 2.3

cumene is 152.4°C. The word normal means

at 1 atm.

3. Click on the TDep tab.

Click on Vapour Pressure.

View the Antoine Coefficients for cumene.




To view the Temperature Dependent

Properties page. The vapor enthalpy

equation and its coefficients are shown.

To change from the Vapour Enthalpy equation

to the Antione Vapor Pressure equation.

To confirm that the Antoine coefficients—a,

b, c, d, e, and f—are shown for cumene.

To close the Cumene window.

To close the Component List View windowand return to the Simulation Basis Manager

window.

4. Click the Enter Simulation Environment… in the lower-right part of the window.

Note that

To enter the simulation environment, whichcontains the PFD window, as well as theObject Palette called “Case (Main)” on the

right. In the PFD, you can add process

streams and unit operations from the Object

Palette to construct your simulation.

Whenever you are in the SimulationEnvironment and you decide to return to the

Simulation Basis Manager, the button for

returning to the Simulation Environment will

always be Return to Simulation

Environment.

D. Create a process stream.

You have just created the fluid package for your HYSYS simulation and viewed

some component physical properties. You are now in the empty PFD ( process

flow diagram) view of your simulation. Streams and unit operations can be added

through the Workbook, but we will use the PFD, a graphical view of the

flowsheet that allows the user to see how the process units and stream are

connected. In the PFD view, the simulation flowsheet is a collection of icons that

represent streams and unit operations. The first step in creating your process

simulation is to make a material stream. This section explains how to create a

material process stream and specify its process stream state. Proceed as follows:

1. Click the blue Material Stream icon in theObject Palette, move the cursor into the PFD,

and click where you want the stream icon to be

positioned.

To add a process stream labeled 1 to the PFD.

If the Object Palette is not visible, choose the

Flowsheet/Open Object Palette menu option

or press the <F4> key on the keyboard.

2. Double-click on the stream 1 icon in the PFD. To open its stream property window, which

contains tabbed views with information about

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Tutorial 2.3

Note that

Note that

the stream and an “object status” area that is

currently yellow.

A property window always shows the status of

the associated object (red for missing

information, yellow for a warning message, andgreen for OK ). HYSYS has successfully done

the object’s calculations when the objectstatus is green.

Currently, the Worksheet/Conditions page

for stream 1 displays empty for all stream

condition cells, because no data have been

specified for the stream yet. Once you supplythe temperature, pressure, flow rate, and

composition for a stream, HYSYS will

automatically calculate all other properties ofthat stream.

3. Enter S1 in the Stream Name cell of stream 1;i.e., click in cell, type a value, and hit the <Enter > key.

To change the stream name from the default

value of 1 to S1. HYSYS assigns a defaultname to every object added to the PFD.

You can control the default name for any

object through the Simulation/Naming pageof the Tools/Preference… menu option.

4. Enter 25 in the Temperature cell of stream S1.

Enter 1 atm in the Pressure cell of stream S1.

To specify the stream temperature at 25°C.

To specify the stream pressure at 1 atm.

HYSYS automatically converts the pressurefrom units of atm to kPa.

5. Enter 100 in the Molar Flow cell of stream S1.

Note that

Double-click on the molar flow value of 100.

Click Mole Fractions in the Composition

Basis area, if necessary.

To specify a molar flow rate of 100 kgmole/h.

Note that the object status is still yellow andsays “Unknown Compositions.” HYSYS is

warning you that the compositions are notspecified yet.

To open the Input Composition for Stream

window.

To select the composition basis as componentmole fractions. The stream composition can

be supplied as mole, mass, or liquid volumefractions. The total flow and composition can

also be set by entering component mole, massor liquid volume flows.

Enter 100 in the MoleFraction cell for benzene.

Enter 3 in the MoleFraction cell for propene.

To specify the relative amount for benzene.

To specify the relative amount for proplyene.

Enter 3 in the MoleFraction cell for propane To specify the relative amount for propane.

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Tutorial 2.3

Enter 94 in the MoleFraction cell for cumene. To specify the relative amount for cumene.

Click on the Normalize button.


Note that


Note that

To convert the input data to mole fractions.

The Normalize task takes your data and

adjusts them so they add up to one.

To return you to the Worksheet/Conditions

page of the stream property window.

The remaining cells of stream S1 now have

values and the object status is green. The

values calculated by HYSYS are black.Values you have supplied are blue. The

calculated stream heat flow is 4.448e+5 kJ/h.

The stream’s heat flow is its molar flow rate

(kgmol/h) times its molar enthalpy (kJ/kgmol).

To close the stream property window.

Stream S1 now appears in the PFD as a dark

blue stream because the stream state has beenspecified. Streams not completely specified

are light blue.

6. Place the cursor over the stream S1 icon in the

PFD.To view the stream conditions. A box willappear listing the stream name, temperature,

pressure, and flow rate.

E. Copy and delete a process stream.

Sometimes you want to create a new process stream and have as its values the

conditions of an existing process stream. You may want to do this action in order

to study other process states of the existing stream without disturbing its current

conditions. For example, you are interested in finding the dew- and bubble-pointtemperatures of stream S1. You will copy the conditions of S1 into a new stream

to determine the dew- and bubble-point temperatures. You will then delete the

copied stream before saving your simulation. Proceed as follows:

1. Add a new material stream to the PFD usingthe blue Material Stream icon in the Object

Palette window.

Note that

To create a stream into which the conditionsof stream S1 will be copied. See Step 1 of the

“Create a process stream” section above for

details on how to add the stream.

A stream labeled 1 now appears in the PFD.

The stream’s process state has not yet beenspecified, so the stream icon is light blue.

2. Double click on the Stream 1 icon in the PFD.

Enter junk into the Stream Name cell.

To open its stream property window.

To change its name from 1 to junk.

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Tutorial 2.3

3. Click on the Define From Other Stream…

button.

Double-click on stream S1 in the Available

Streams area.

Click the Close button..

To open a window showing the streams that

are available for copying.

To choose the conditions of stream S1 to be

copied into stream junk. The object status at

the bottom of the property window for stream junk turns green and shows OK, indicating

the new stream now has been determined.

To close the property window of stream junk.

4. Click the Workbook icon on the button bar.

Empty the Temperature cell of stream junk,

using the <delete> (not the <backspace>) key.

Note that

Enter 1 into the vapor fraction cell of junk.

Enter 0 into the vapor fraction cell of junk.

Click the PFD icon in the button bar.

To open the simulation workbook. The

Material Streams page shows both S1 and junk with identical properties.

To deactivate the calculated conditions of

stream junk.

Two of those three cells for vapor fraction,temperature, and pressure must be given

values for a stream to be specified.

To find its dew-point temperature, a conditionwhen the first drop of liquid forms out of the

vapor phase. HYSYS calculates a dew-pointtemperature of 130.5°C for stream junk.

To find its bubble-point temperature, a

condition when the first bubble of vapor formsout of the liquid phase. HYSYS calculates a

bubble-point temperature of 60.69°C for junk.

To return to the Process Flow Diagram.

5. Click on the junk stream icon in the PFD;

hit the <delete> key on the keyboard;click the Yes button.

Note that

To delete stream junk from your simulation.

You are left with only stream S1 in the PFD.

By default, you always get the “Do you wishto delete” confirmation for each object that

you want to delete from the PFD.

If you are deleting many objects at the sametime, answering the delete confirmation

message for each object came be frustrating.

You can deactivate the delete confirmation

through the Simulation/Options page of theTools/Preferences… menu option.

F. Save the simulation.

You have created a simulation file identical to intro.hsc. More streams and unit

operations can be added to the simulation at a later time. To save a current

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Tutorial 2.3

simulation for later use, you can save the file to your personal folder. Proceed as

follows:

1. Choose File/Save from the menu bar.

Look in the pull-down menu▼, select yourstudent server (U:) icon, and navigate to your


Enter simul in the File Name cell,then click the Save button.

To display the Save Simulation Case As window.

To save the new simulation case file in one ofyour personal folders.

To name and save your simulation file to thenetwork file server for later use.

2. Choose File/Exit from the menu baror


To exit the HYSYS program, if you do not plan to do the next simulation tutorial.

Beef, Inc. 2-21 8/15/05




Tutorial 2.4

Heater and Case Study

In Tutorials 2.2 and 2.3, you conducted a HYSYS simulation on a single process stream

that contained benzene, propylene, propane, and cumene. In this tutorial, you will add a heater

unit operation to the simulation and then conduct a case study analysis on that heater. You will begin with the existing file named heat.hsc located on the network file server. The pre-defined

simulation in this file is set for the Peng-Robinson-Stryjeck-Vera (PRSV) fluid package with four

chemical components and a liquid process stream, named S1.

The process state of Stream S1 is given below in the conceptual diagram for the heater. Using

HYSYS, you will determine what duty ( in kJ/h) is required to heat stream S1 to a saturated

vapor at 162 kPa.

Q

S1 S2E1

heater

V

T C

P kPa

n kgmol h

z

z

z

z

f S

S

S

S

S BZ

S PY

S PR

S CU

,

,

,

,

,

?

/

.

.

.

.470

1

1

1

1

1

1

1

1

25

175

200

0 500

0 015

0 015

0

=

=

=

=

=

=

=

=

V

T

P k

n

z

z

z

z

f S

S

S

S

S BZ

S PY

S PR

S CU

,

,

,

,

,

.

?

?

?

?

?

?

2

2

2

2

2

2

2

2

1 0

162 Pa

=

=

=

=

=

=

=

=

?Q E 1 =

Then you will perform a case study to observe the heat duty-temperature profile for this heater

operation. This tutorial is divided into six sections—start the HYSYS program, open an existing

simulation file, add a heater operation, specify the heater outlet condition, perform a case study,

















bar.



3. Select the Variables/Units page. To display the Units preference page in the

Variables view.

Beef, Inc. 2-22 8/15/05




Tutorial 2.4


if necessary.







B. Open an existing simulation file.


for you to access. It is called heat.hsc. This file is the basis for this tutorial that

simulates a heater unit operation and generates a case study plot. Proceed as

follows to open heat.hsc and save a copy of it:



or









Manual/Chap 2.

To find the HYSYS simulation file heat.hsc


Manual folder.

3. Double-click on the file named heat.hsc,

or


To open the pre-defined simulation file. The

Process Flow Diagram (PFD) window









or


Note that




To save the file on the Windows computer.

Saving a file to the computer will result in

faster simulations, since HYSYS will not haveto transfer data over the network. Simulation


larger.





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Tutorial 2.4

Click the Save button. To save your heat.hsc simulation file.

C. Add a heater operation.

Now that you have opened the existing file and saved it into your personal folder,

you can modify the simulation. This section explains how to add a heater operation

to the process stream in the existing Process Flow Diagram (PFD). In the

simulation, inlet Stream S1 is to be vaporized by Heater E1 with a duty stream

QE1 and an outlet Stream S2, as shown in the figure above.

1. Press the <F4> function key on the keyboard;

then drag the resulting window to the far right

in the HYSYS desktop.

Note that

Click the Heater icon in the Object Palette;

move the cursor into the PFD just to the right

of stream S1; and click the mouse button.

To open and position the Object Palette

window of icons for process streams and unit

operations.

Moving the cursor over a palette icon will

reveal its name.

To add the HEATER unit operation into the

PFD window. The heater icon is labeled with

E-100.

2. Double click on the E-100 icon in the PFD.

Note that

To open its property window, which contains

tabbed views with information about the

heater and its inlet and outlet streams.

The Design/Connections page is currently

visible in the E-100 property window for the

heater object.

A property window always shows the status

of its object (red for missing information, yellow

for a warning message, and green for OK ).

HYSYS has successfully done an object’s

calculations when its object status area is

green.

3. Select Design/Connections page, if necessary.

Enter E1 in the Name cell of this page;

i.e., click in cell, type a name, and hit the <Enter > key.

Note that

To view the Connections page of E-100.

To change the heater name from the default of

E-100 to E1. HYSYS assigns a default name

to every stream and unit operation that you

create.

The red object status of “Requires a feed

stream” im plies that you must connect an inlet

stream to heater E1.

4. Click in the Inlet cell and select S1 from the

drop-down menu of▼.

or

To connect stream S1 as the feed stream to the

heater process operation.

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Tutorial 2.4

Enter S1 in the Inlet cell.

Note that The red object status of “Requires a product

stream” implies that you must connect an

outlet stream to heater E1.

5. Enter S2 in the Outlet cell.

Note that

To define stream S2 as the product streamleaving the heater process operation.

Stream S2 did not previously exist in the

flowsheet. Thus, naming the heater outlet as

S2 creates a new process stream called S2.

The red object status of “Requires a energy


energy stream to heater E1.

6. Enter QE1 in the Energy cell.

Note that

Note that

To define stream QE1 as the energy stream

that will supply heat to the heater process

operation.

Energy stream QE1 did not previously exist

in the flowsheet. Thus, naming the heater

duty creates a new energy stream called QE1.

You picked the name QE1 because symbol Q

stands for heat duty and “E1” implies that this

Q is associated with unit operation E1.

The yellow object status of “Unknown Delta

P” implies that you must supply additional

data before HYSYS can simulate heater E1.

You are going to simulate the heater as shownmathematically by:

Ψ Δ ΨS E E S f S S

P Q heater V P2 1 1 1 2

1, , , ,,

= =2

where heater is the function whose variables

on the left are calculated by HYSYS once

those variables on the right are specified. The

vector Ψi is a short notation to represent the

temperature, pressure, flow rate, and chemical

composition of Stream i.

7. Click the Close button.

Note that

To close the property window of object E1.The PFD now contains the heater E1 icon

with a dark blue inlet stream S1, a light blue

outlet stream S2, and a light maroon duty

stream QE1.

A process stream fully determined by HYSYS

is dark blue in the PFD, while a process

stream not fully determined is light blue.

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Tutorial 2.4

Similarly, energy streams fully determined are

dark maroon, and energy streams not fully

determined are light maroon.

The S2 and QE1 icons appear in light colors

because HYSYS can not calculate them untilyou specify two more conditions, as implied

by the mathematical function in Step 6 above.

8. Click the cursor to the left of stream S1.

Select the QE1 icon an drag it up about 1 inch.

To de-select the E1, QE1, and S2 icons in the

PDF.

To re-position the QE1 icon so that the S2

icon is more visible.

D. Specify the heater outlet condition.

You have added a heater to your simulation and connected the inlet, outlet and

duty streams. The inlet stream conditions have been determined by HYSYS

using a temperature and pressure of 25°C and 175 kPa. In this simulation, stream

S1 is to be heated to a saturated vapor at 162 kPa. Once you specify the outlet

stream vapor fraction and pressure, HYSYS will automatically calculate the

heater’s pressure drop and heat duty. Proceed as follows:

1. Double-click on the E1 icon in the PFD.

Click on the Worksheet tab.

To open its property window of tabbed views.

To view the Worksheet/Conditions page for

the heater’s inlet, outlet, and duty streams.

2. Place cursor on the right border of this view;

wait for cursor to change to symbol ↔, then

drag the border to the right.

Note that

To stretch the property window so you can

see the properties of all three streams

connected to heater E1.

Stream S1 is fully determined but material

stream S2 and energy stream QE1 are not.

Stream QE1 has one blue empty cell, while

stream S2 has six. A blue empty cell implies

you can input a value in that cell, except for

the last three cells in S2. HYSYS can only

enter values for these cells. Of the three

acceptable blue empty cells, you must supply

values for any two before HYSYS will do the

calculations.

3. Enter 1 in Vapour fraction cell of stream S2.

Enter 162 kPa in Pressure cell of stream S2.

Note that

To specify a saturated-vapor outlet condition.

To specify the pressure of the outlet stream.

With these two variables specified, the object

status area turns green, which indicates that

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Tutorial 2.4

Note that

HYSYS did the calculation successfully.

The remaining cells of streams QE1 and S2

are now filled with black, calculated values.

4. Select the Design tab, then the Parameters page.

Note that

To view the heater parameters calculated byHYSYS for your specified outlet conditions.

The calculated pressure drop is 13 kPa, and

the calculated heater duty is 1.0848e+7 kJ/h.

Once you have specified the process state of

the inlet stream, the heater can be simulated

by specifying any two of the following

variables: pressure drop, heat duty, outlet

vapor fraction, outlet temperature, and outlet

pressure.

5. Click the Close button. To close the property window of unit

operation E1. The heater and stream icons inthe PFD are now dark colors, indicating the

heater equations have been successfully

solved, and all stream and heater variables are

determined.

6. Click the Save Case icon in the button bar. To save the heater simulation case as a file

named heat.hsc in one of your personal

folders on the network file server.

E.

Perform a case study.

You have just completed the steady-state simulation for the heater process

operation. Now you will add a case study to the flowsheet. The case study tool

allows you to monitor the steady-state response of key process variables to

changes in your process. From the list of variables created on the Variables

page, you designate the independent and dependent variables for each case study.

For each independent variable, you will specify a lower and upper bound, as well

as a step size. HYSYS varies the independent variables one at a time, and with

each change, the dependent variables are calculated and a new State (or data

point) is defined. Once the Case Study has solved for all data points, you can

examine the States in a table or view the results in a plot.

Basically, the case study provides a mechanism for you to do “what if” analyses.

For example, how does the heat duty of heater E1 vary when the outlet

temperature of stream S2 is changed from 25ºC to 250ºC in increments of 5ºC?

The HYSYS Data Book task gives you the tools to conduct this “what if”

analysis. To produce a plot of heat duty versus temperature, proceed as follows:

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Tutorial 2.4

1. Choose Tools/DataBook from the menu bar.

Press the <F4> key to hide the Object Palette.

To open the DataBook window and begin

your "what if" analysis.

You will be using the Variables and Case

Studies tabs to do your “what if” analysis.

2. Click on the Variables tab, if necessary.

Click the Insert… button.

Click QE1 in the Object column;

Click Heat Flow in the Variable column;

Click the Add button.

Click S2 in the Object column;Click Temperature in the Variable column;



To view Variables page of the Data Book.

You must identify those variables in the PFD

that are to be monitored by the Data Book.

To open the Variable Navigator window.

To connect the heat flow of the QE1 energy

stream in the PFD to the Data Book. This

variable will be used in the plot of heat duty

versus outlet temperature.

To connect the outlet temperature of streamS2 in the PFD to the Data Book. This

variable will be used in the plot of heat duty

versus outlet temperature.

To return to the Variables page. You have

just identified the two variables in the PFD

that the Data Book will monitor. You are

now ready to perform the case study analysis.

3. Click the Case Studies tab.

Click the Add button in the Available CaseStudies area.

Enter Heater E1 Duty Profile in the Current

Case Study cell of the Case Studies Data

Selection area.

To view the Case Studies page and begin

defining your “what if” analysis.

To create a new case study in the Data Book. Note that the Case Studies Data Selection

area becomes activated.

To give a unique identification to your case

study for a plot of heat duty versus outlet

temperature.

You are ready to select the dependent variable

as the heat duty and the independent variable

as the outlet temperature.

4. Click the Ind check box for temperature in the

Case Studies Data Selection area.

Note that you get an error message window.

Press the OK button.

To identify the outlet temperature of stream

S2 as the independent variable in your study.

To correct the conflict that the temperature of

stream S2 is not modifiable; that is, it is not a

specified variable with a blue value in the

PFD.

To remove the error message. You will now

change the calculation algorithm of heater E1

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Tutorial 2.4

Press the Workbook icon on the button bar.

Delete the vapor fraction value of stream S2;

enter 25ºC in the Temperature cell of thisstream.

Choose Window/DataBook from the menu

bar.

to specify the outlet temperature of stream S2.

To see the streams in the Workbook window.

To specify the temperature instead of vapor

fraction in this stream. You have just madethe independent variable of a case study be a

specified, and thus a modifiable, variable in

the PFD simulation.

To return to the DataBook window with the

Case Studies page in view.

5. Click the Ind check box for temperature again.

Click the Dep check box for the heat duty.

Click the View... button in the Available Case

Studies area.

To make it the independent variable.

To make it the dependent variable.

To access the Case Studies Setup window, in

which you will specify the value range of theindependent variable for your case study.

6. Enter 25ºC in the Low Bound cell;

Enter 250ºC in the High Bound cell; and

Enter 5ºC in the Step Size cell.

To specify the range for the outlet temperature

of stream S2 in the case study.

This range creates 46 data points in your case

study, as indicated by the Number of States

area.

7. Click the Start button in lower right of the

window.

Click the Results button immediately after you

have pressed the Start button.


in the upper-right part of the Case Studies

window.

Note that



To begin the Data Book calculations. For

each data point, the Case Study task request a

simulation to be done in the PFD and then

tabulates the result for the dependent variable.

To watch HYSYS generate the plot of heat

duty versus outlet temperature.

To enlarge the view of the plot. If you click

the Table radio button at the bottom of the

window, you can view each data point

generated by the Case Study task.

If you right click the mouse anywhere in the

plot, you can change its appearance and even

print it. For example, by selecting “Graph

Control” you can change the labels of the axesto be more descriptive.

To return to the Case Studies Setup window.

To return to the Case Studies page of the

DataBook window.

You have just completed a Case Study task.

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Tutorial 2.4

This task greatly increases your ability to do

“what if” analysis in a reasonable amount of

time.

8. As a challenge, experiment with making the

heat duty the independent variable and thetemperature the dependent variable

You will need to change the conditions on

streams S2 and QE1 to reflect this new modeof calculation, before you try to do the case

study.

F. Close the simulation case.

You will close the file containing your simulation case and then possibly exit

HYSYS.




not save it.


or


To exit the HYSYS program, if you do not

plan to do the next simulation tutorial.

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Tutorial 2.5

HYSYS Printing Capabilities

This tutorial shows you how to document HYSYS results by printing the process flow

diagram (PFD), specification sheets (datasheets), and reports. A report puts multiple datasheets into

one package and prints them out together. Case study tables and plots can also be printed byHYSYS.

You will document the HYSYS simulation created in the “Heater and Case Study” of

Tutorial 2.4. Your documentation activity in this tutorial is divided into seven sections—start the

HYSYS program, open an existing simulation file, print its PFD and an active window, print the

heater E1 datasheets, print the E1 case study plot, create a report, and close the simulation case.

To proceed, you must be familiar with the material in Tutorial 2.4.


When you start the HYSYS program, it always begins with whatever global preference settings were last saved in your default preference file. You should












2. Choose Tools/Preferences… from the menu bar. To display the Session Preferences windowwith tabbed preference views.



if necessary.


Variables view.









for you to access. It is called print.hsc. This file is the basis for this tutorial that

prints a process flow diagram, an active window, heater datasheets, and a case

study plot. Proceed as follows to open print.hsc and save a copy of it:

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Tutorial 2.5



or









Manual/Chap 2.

To find the HYSYS simulation file print.hsc


Manual folder.

3. Double-click on the file named print.hsc,

or



Process Flow Diagram (PFD) window




defined simulation case as a new simulationcase file in one of your personal folders.




or


Note that










larger.





To save your print.hsc simulation file.

C. Print the PFD and an active window.

A hardcopy of the process flowsheet is obtained by printing the HYSYS PFD

window. You can also print a hardcopy of an active window other than the PFD,such as a page in the property window of a unit operation. In this tutorial you

will print the PFD of file print.hsc and a worksheet page of the heater property

window. Proceed as follows:

1. Click the Zoom All button in lower left of the

PFD window located between the – and +.

Note that

To place the entire flowsheet in the PFD

window.

HYSYS prints only what is shown in this

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Tutorial 2.5

window. If you want to see the whole

flowsheet, view all of the PFD with the Zoom

All button before printing.

2. Choose File/Print Setup/Graphic Printer…

from the menu bar.

Check and set the Printer Name cell.


To change the printer settings for the printing

of the PFD, plots, strip charts, and snapshots.

To select your destination printer.

To return to the HYSYS desktop.

3. Choose File/Print… from the menu bar.

Note that

To print what is shown in the PFD window.

When printing the PFD, HYSYS prints

automatically and does not give you the

chance to preview what will be printed.

Because of this fact, be sure the PFD contains

what you want to be printed.

4. Double-click on heater E1 icon in the PFD.

Select the Worksheet/Conditions page.

Place cursor on the right border of this view;

wait for cursor to change to symbol ↔, then

drag the border to the right.

Note that


To view the conditions of the heater’s inlet,

outlet, and duty streams.



connected to heater E1.

If the E1 window is in the modal view, click

the pin icon in the upper right corner next to

the icon to change this window to the non-

modal view. You must be in the non-modalview to do Step 5 below.

5. Choose File/Print Window Snapshot from the

menu bar.

Note that

Click the Close button of the E1 property view.

To print the active window, the

Worksheet/Conditions page of the E1

property window, as it appears on the screen.

When printing this view, HYSYS prints

automatically and does not give you the

chance to preview what will be printed.

Because of this fact, be sure the active

window contains what you want to be printed.

To return to the PFD window.

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Tutorial 2.5

D. Print the heater datasheets.

A datasheet is a printout of information—specifications and results—about a

worksheet, process stream or unit operation. Four types of datasheets—Design,

Worksheet, Performance, and Dynamics—exist. For this tutorial, you want the

inlet and outlet stream states to be included, so you will choose the Design and

Worksheet datasheet. Proceed as follows to print information for heater E1:

1. Double-click on heater E1 icon in the PFD.

Note that


To print a stream or unit operation datasheet,

the property window of that object must be

the active window in the HYSYS desktop.

Step 2 below requires that the E1 window be

in the non-modal view, before you try to print.

2. Choose File/Print Setup/Report Printer… from the menu bar.

Check and set the Printer Name cell.

Note that


To change the printer settings for the printingof datasheets, reports, and text.

To select your destination printer.

This printer can be the same as the HYSYS

graphics printer, if it is a laser printer.

To return to the HYSYS desktop.

3. Choose File/Print… from the menu bar. To open the Select Datablocks window with

its options of available datasheets for the

heater E1 object.

4. Uncheck all Datablocks except for Design and

Worksheet.

Click on the Preview… button

Note that

.

To select the design and worksheet datasheets

for heater E1.

To see what will be printed.

You should always preview to ensure that the

chosen datasheets contain the information that

you desire.

5. Click on the Print button.


Click the Close button.Click the Close button.

To print the selected datasheets of heater E1.

To close the Report Preview window.

To close the Selected Datablocks window.To close the heater E1 property window.

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Tutorial 2.5

E. Print the case study plot.

The heater case study created in the “Heater and Case Study” tutorial produced a

plot of heater duty versus outlet temperature. This case study is already included

in the print.hsc file. Proceed as follows to print the case study plot:

1. Choose Window/Case Studies – Main from

the menu bar.

To view the case study plot of the Heater E1

Duty Profile.

2. Click the secondary-mouse button in the plot.

Note that

Click on the Print Plot button.

Note that

To open the popup menu with many options.

The secondary mouse button is normally the

right button, provided you have not changed

the mouse settings through Windows.

To print the case study plot for heater E1.

HYSYS automatically prints a full-page

version of this case study plot.

Before you print, you could select the Graph

Control button of the popup menu to set

color, symbol, line style, axis label, title, etc.

3. Click the Close button. To close the case-study plot window and

return to the PFD window.

F. Create a report.

In Step D above, you used the File/Print… menu to print the Design andWorksheet datasheets for the heater. This technique of printing will always

present the Design datasheet first followed by the Worksheet datasheet. If you

would like to, you can compile datasheets into a different order using the HYSYS

report capability. Proceed as follows to create a customized, two-page report for

the heater simulation in this tutorial:

1. Choose Tools/Reports from the menu bar.

Click the Create… button.

Enter Heater E3 Report in Report Name cell;


Click the Insert Datasheet… button.

To open the Report Manager window.

To open the Report Builder window.

To give your simulation report a unique and

understandable identification.

To open the Select Datablocks for Datasheet

window.

2. Click Pick a Specific Object by Name in the

Source for Datablocks area, if necessary.

To display all of the flowsheet objects in the

Objects area with a filter of All.

3. Click S1 under the Objects area, then select To place only the worksheet datasheet for

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Tutorial 2.5

only Worksheet in Available Datablocks,


Click S2 under the Objects area, then select

only Worksheet in Available Datablocks,


Click E1 under the Objects area, then select

only Design in Available Datablocks area,


Click the Done button.

Stream S1 in the customized report that you

are building.

To place only the worksheet datasheet for

Stream S2 in the customized report that you

are building.

To place only the design datasheet for heater

E1 in the customized report that you are

building.

To return to the Report Builder window,

which now displays the datasheets in the order

in which they will be printed in your

customized report.

4. Click the Preview button at the bottom of the

window.

Note that

To view your customized report in the Report

Preview window.

You can scroll through this window to see the

contents of your report.

If you are satisfied with the report’s contents,

you can print this report by clicking the Print

button.

5. Click the Close button in Report Preview.

Click the Close button in Report Builder.

Note that

Click the Close button in Report Manager.

To return to the Report Builder window.

To return to the Report Manager window.

Heater E3 Report is listed in the Reports

area of this window.

To close the Report Manager window and

return to the PFD window.



HYSYS.




not save it.


or




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Tutorial 2.6

Conversion Reactor and Reactions

In Tutorial 2.4, you conducted a HYSYS simulation on heating a process stream that

contained benzene, propylene, propane, and cumene. In this tutorial, you will add a reactor unit

operation to the simulation. You will begin with the existing file named conv.hsc located on thenetwork file server. The pre-defined simulation in this file is set for the Peng-Robinson-Stryjeck-

Vera (PRSV) fluid package with four chemical components and a heater process unit, named E1.

Reaction information (i.e., stoichiometric equations with their models) can be attached to certain

HYSYS process unit operations to simulate the reaction of chemical compounds. Reactions can

be specified in HYSYS by conversion, equilibrium, or kinetic models. This tutorial shows you

how to add a conversion reactor and the needed reaction information for the isothermal, vapor-

phase reaction of propene and benzene to form cumene, as expressed by the following

stoichiometric equation:

C3H6 + C6H6 → C9H12

In the conceptual model below, you will determine what duty ( in kJ/h) is required to operate

the isothermal reactor R1; that is, how much heat is required for the endothermic reaction, so that

the inlet (S2) and outlet (S3) streams are at the same temperature.

Q R1

T C

P kPa

S

S

2

2

350

3075

=

=

T C

P kPa

n kgmol h

z

z

z

z

S

S

S

S BZ

S PY

S PR

S CU

1

1

1

1

1

1

1

25

3095

329 6

0 648

0 335

0 017

0 0

=

=

=

=

=

=

=

. /

.

.

.

.

,

,

,

,

T C

P k

n

z

z

z

z

S

S

S

S BZ

S PY

S PR

S CU

3

3

3

3,

3,

3,

3,

350

3025

=

=

=

=

=

=

=

?

?

?

?

?

Pa

S1E1

heater

?Q E 1 =

S2 S3R1

reactor

?Q R1 =

The molar conversion of propene for reactor R1 (i.e., amount reacted divided by the amount fed) is

eighty-three percent for a specific catalyst. This tutorial is divided into six sections—start the

HYSYS program, open an existing simulation file, add a reaction to the fluid package, add a

reactor to the flowsheet, specify the reactor outlet conditions, and close the simulation case. To

proceed, you must be familiar with the material in Tutorial 2.4.






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Tutorial 2.6











bar.



.



if necessary.


Variables view.









for you to access. It is called conv.hsc. This file is the basis for this tutorial that

simulates a reactor unit using a conversion reaction model. Proceed as follows to

open conv.hsc and save a copy of it:



or









Manual/Chap 2.

To find the HYSYS simulation file conv.hsc


Manual folder.

3. Double-click on the file named conv.hsc,

orSelect this file and click the Open button.


Process Flow Diagram (PFD) window and the Workbook window appear in the HYSYS

desktop.





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Tutorial 2.6




or


Note that






Saving a file to the computer will result infaster simulations, since HYSYS will not have



larger.





To save your conv.hsc simulation file.

C. Add a reaction to the fluid package.

Reaction information (i.e., stoichiometric equations with their models) must be supplied

to the Reaction Manager in the Simulation Basis Manager. These reactions

must be connected to a fluid package before a reactor can be simulated in the

process flow diagram (PFD), often called a flowsheet.

When building a fluid package for a new simulation that will contain a reaction

or reactions, the reaction information is usually connected to the fluid package

before the flowsheet is created. However, the fluid package can be altered

throughout the process simulation, and reactions can be connected to the fluid package later.

The fluid package in conv.hsc does not contain the necessary reaction

information for the reaction of propylene and benzene to form cuemene. Using

the Reactions page of the Simulation Basis Manager, you create a chemical

reaction and add it to a reaction set, and you then attach a reaction set to the fluid

package. Proceed as follows:

1. Click on the Enter Basis Environment icon in

the button bar.

Click on the Reactions tab.


window that contains tabbed views.

To view the Reactions page. This page iswhere you can define an unlimited number of

reactions and collect combinations of these

reactions into reaction sets.

2. Click the Add Rxn… button in the Reactions

area on the middle of the page.

Click Conversion in the Reactions pop-up

To open the Reactions window and create a

new chemical reaction.

To select it as the chemical reaction model.

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Tutorial 2.6

window, if necessary.

Click the Add Reaction button.

.

Enter PY Conversion in the Name cell at the bottom of the window.

Note that

Other types of models that you can select

from are equilibrium and kinetic.

To open the Conversion Reaction window.

To give the reaction you are about to define aunique identification, for the conversion of

propylene (propene) and benzene to form

cumene.

The status area of the Conversion Reaction

window currently is a red Not Ready,

meaning that you must supply more reaction

information.

3. Click the cell in the Component column with a

blue **Add Comp** value in it.

Choose propene from drop-down menu of▼

near the top of Conversion Reaction window.

Repeat for benzene and cumene, in that order.

Note that

To begin the procedure of selecting the

chemical components in the cumene reaction.

To add propylene to the chemical reaction.

To complete the components in the reaction.

Propane does not participate in the reaction;

therefore, it is not entered into the

Conversion Reaction window.

4. Enter -1 in the Stoich Coeff cell for propene.

Enter -1 in the Stoich Coeff cell for benzene.

Enter 1 in the Stoich Coeff cell for cumene.

Note that

Note that

Note that

To specify the stoichiometric coefficients of

all three chemical components. These

components are in a 1:1:1 molar ratio.

Reactants must have negative stoichiometriccoefficients, while products must have

positive stoichiometric coefficients.

The Balance Error cell will equal zero when a

valid reaction stoichiometry is specified.

The status area is still a red Not Ready,

meaning you must supply a conversion basis.

5. Click on the Basis tab.

Enter Propene in the Base Component cell,using the drop-down menu of▼, if necessary.

Note that

To view the Basis page of the Conversion

Reaction window.

To specify propene as the base component fora conversion reaction model.

The base component is the limiting reactant in

a chemical reaction. Since stream S2 contains

213.6 kgmol/h of benzene and 110.5 kgmol/h

of propene, propene is the limiting reactant.

To specify an 83% molar conversion of

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Tutorial 2.6

Enter 83 in the Co coefficient cell.

Note that



Note that

Note that

Note that

propene. This means that 83% of the propene

fed to the reactor will react to form cumene.

The status area in the Conversion Reaction

window is now a green Ready message. You

have just completed the specification for oneconversion reaction.

To close the Conversion Reaction window.

To close the small Reactions window and

return to the Reactions page of the Simulation

Basis Manager.

The Reactions area in the middle of the

Reactions page lists PY Conversion as the

first reaction in the Reaction Manager. If you

had other reactions to define, you would

proceed to add them through the Add Rxn…

button, like you did for the cumene reaction.

All reactions in the Reactions area are placed

automatically into the Global Rxn Set by

HYSYS. This set is listed in the Reaction

Sets area at the right side of the Reactions

page.

For different reactions to be carried out in

different process units of a process flow

diagram (PFD), new reaction sets need to be

created in the Reaction Sets area of the

Reaction Manager. Since you need only one

reaction for this tutorial simulation, you canconnect the pre-defined global reaction set to

a fluid package.

6. Click Global Rxn Set in the Reaction Sets

area, if it is not selected.

Click the Add to FP button at the bottom of the

Reaction Sets area.

Click Basis-1 in the Add ‘Global Rxn Set’ window, and then click the Add Set to Fluid

Package button.

Note that

To choose the global reaction set. This global

set contains only the PY Conversion reaction.

To associate the global reaction set with the

current fluid package. The reaction set must

be added to the fluid package in order for the

reactions to be used in a process unit of a

flowsheet.

To add the global reaction set to the Basis-1 fluid package.

Basis-1 now appears under the Associated

Fluid Packages of the Reaction Sets area.




contains the PFD and workbook windows.

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Tutorial 2.6

You have just completed the addition of a

conversion reaction to your fluid package.

D. Add a reactor to the flowsheet.

Now that you have added the reaction information to the simulation fluid

package, you can add a reactor vessel to the simulation. HYSYS contains many

reactor modules, including general reactors (such as conversion and equilibrium

reactors), plug flow reactors, and continuous stirred tank reactors. You will use a

general conversion reactor for the simulation of the cumene reaction. This

section explains how to add a reactor operation to the existing process flow

diagram. The heated stream S2 is fed to reactor R1 to create a reactor product

called stream S3, as depicted in the figure at the beginning of this tutorial. The

reactor requires a duty stream QR1. Proceed as follows to add the conversion

reactor to the PFD:

1. Press the <F4> function key on the keyboard;


in the HYSYS desktop.

Note that

Click the General Reactors icon in the Object

Palette.

Click the Conversion Reactor icon in the sub-

palette; move the cursor into the PFD just to

the right of and slightly below stream S2; and

click the mouse button.



operations.


reveal its name.

To open a small, sub-palette window that

contains three general reactor icons.

To add the CONVERSION REACTOR unit

operation into the PFD window. The reactor

icon is labeled with CRV-100.

2. Double click on CRV-100 icon in the PFD.

Note that



reactor and its inlet and outlet streams.

The Design page is currently visible in the

CRV-100 property window for the reactor.

A property window always shows the statusof its object (red for missing information, yellow




green.


To view the Connections page of CRV-100.

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Tutorial 2.6

Enter R1 in the Name cell of this page;


Note that

To change the reactor name from the default

of CRV-100 to R1. HYSYS assigns a default

name to every stream and unit operation that

you create.

The red object status of “Requires a feedstream” implies that you must connect an inlet

stream to reactor R1.

4. Click in the topmost Inlets cell and select S2

from the drop-down menu of▼ near the top

right of the window.

or

Enter S2 in this cell.

Note that

To connect stream S2 as the feed stream to the

conversion reactor operation. HYSYS allows

multiple feed streams to reactors. Your

simulation requires only one feed stream.

The red object status of “Requires a product


outlet stream to reactor R1.

5. Enter S3 in the Vapour Outlet cell.

Enter S4 in the Liquid Outlet cell.

Note that

Note that

To define stream S3 as the product streamleaving the reactor process operation.

Stream S3 did not previously exist in the

flowsheet. Thus, naming the reactor outlet as

S3 creates a new process stream called S3.

To define stream S4 as the liquid stream.

Conversion reactors in a HYSYS simulation

may produce a vapor outlet stream, liquid

outlet stream, or both. In your simulation, the

reaction is in the vapor phase only; however,

HYSYS requires that a liquid product stream be defined.

The red object status of “Requires a Reaction

Set” implies that you must supply additional

data before HYSYS can simulate reactor R1.

6. Enter QR1 in the Energy cell.

Note that

To define stream QR1 as the energy stream

that will supply heat to the endothermic

reaction of the reactor operation.

Energy stream QR1 did not previously exist

in the flowsheet. Thus, naming the rector

duty creates a new energy stream called QR1.You picked the name QR1 because symbol Q

stands for heat duty and “R1” implies that this

Q is associated with unit operation R1.

An energy stream is optional for the reactor.

An adiabatic reactor would not have a duty

stream. You are simulating an isothermal

reactor (i.e., same inlet and outlet temperature),

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Tutorial 2.6

Note that

Note that

and it requires a duty stream.



data before HYSYS can simulate reactor R1.

You are going to simulate the reactor as

shown mathematically by:

Ψ Δ ΨS R R S S S

P Q reactor T P3 1 1 2 3, , , ,=

3

where reactor is the function whose variables




temperature, pressure, flow rate, and chemical

composition of Stream i.


Note that

To close the property window of reactor R1.

The PFD now contains the reactor R1 icon

with a dark blue inlet stream S2, a light blue

outlet stream S3, and a light maroon duty

stream QR1.







The S3 and QR1 icons appear in light colors

because HYSYS can not calculate them until

you specify two more conditions, as implied

by the mathematical function in Step 6 above.

E. Specify the reactor outlet conditions.

You have added a conversion reactor to your simulation and connected the feed,

product, and duty stream names. The feed stream conditions are already known

from the HYSYS simulation of the heater E1 operation. You must now connect

the conversion reaction set for cumene to the reactor, and then specify the

product stream temperature and pressure. Once you have made these

specifications, HYSYS will automatically calculate the reactor’s pressure drop

and heat duty. The calculations for reactor R1 involve the algebraic solution of

the material and energy balances. Proceed as follows:

1. Double-click on the R1 icon in the PFD. To open its property view of tabbed views.

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Tutorial 2.6

Select the Reactions/Details page.

Click the cursor in the Reaction Set cell.

Select Global Rxn Set from the drop-downmenu of▼ to the right of this cell.

Click the View Reaction… button in the upper



Note that

To view the details for the chemical reactions.

You must attach a reaction set to reactor R1.

To get the vertical bar in that cell.

To connect the global reaction set to reactorR1 for the cumene reaction.

The Conversion Reaction page shows a

green Ready message and a conversion value

of 83% for the PY Conversion reaction. The

cell with the blue value of 83.00 can be

changed at any time. For now, leave it at

83%.

To return to the Reactions/Details page.

The yellow object status of “Unkown Duty”

near the bottom of the window implies thatyou must supply additional data before

HYSYS can simulate reactor R1.

2. Select the Design tab, then the Parameters

page.

Click in the Delta P cell, and then

hit the <Delete> key.

Note that

To view the Design/Parameters page in the

R1 - Global Rxn Set window.

To de-activate its blue value of 0.0000 kPa to

a blank cell. By this action, you inform

HYSYS to calculate the Delta P value.

Since you will be specifying the reactor outlet

stream pressure, HYSYS will then calculate

the pressure drop (Delta P) from the knownvalues of the feed and outlet stream pressures.

3. Select the Worksheet tab, then the Conditions

page.

If necessary, place cursor on the right border of

this view; wait for cursor to change to symbol

↔, then drag the border to the right.

Note that

To view the conditions of the reactor’s inlet,



see the properties of all four streams

connected to reactor R1.

Stream S2 is fully determined but material

stream S3 and energy stream QR1 are not.

Stream QR1 has one blue empty cell, while

stream S3 has nine. A blue empty cell impliesyou can input a value in that cell, except for

the last four in stream S3. HYSYS can only

enter values in these cells. Of the first four

blue empty cells, you must supply values for

any two before HYSYS will do the

calculations.

4. Enter 350 °C in the Temperature cell of S3. To specify a temperature for the outlet stream.

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Tutorial 2.6

Enter 3025 kPa in the Pressure cell of S3.

Note that

Note that

To specify a pressure for the outlet stream.




The remaining cells of streams QR1 and S3



page.

Note that

To view the reactor parameters calculated by

HYSYS for your specified outlet conditions.


the calculated reactor duty is –9.1187e6 kJ/h.


the feed stream, the reactor can be simulated


variables: pressure drop, heat duty, outletvapor fraction, outlet temperature, and outlet

pressure.

6. Click the Close button. To close the property window of unit

operation R1. The reactor and stream icons in

the PFD are now dark colors, indicating the

reactor equations have been successfully

solved, and all stream and reactor variables

are determined.

F.

Close the simulation case.


HYSYS.



To place the entire flowsheet in full view of

the PFD window.

2. Click the Save Case icon in the button bar. To save the reactor simulation case as a file

named conv.hsc in one of your personal

folders on the network file server.

3. Choose File/Close Case from the menu bar.or

Press the <Ctrl><Z> keys simultaneously.

To close the current simulation case file.


or




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Tutorial 2.7

Gibbs Equilibrium Reactor

In Tutorial 2.6, you conducted a HYSYS simulation on a flowsheet that contained a

heater and an isothermal reactor that had benzene, propylene, propane, and cumene flowing

through them. You learned how to define a conversion reaction set for the followingstoichiometric equation:

C3H6 + C6H6 → C9H12

propene benzene cumene

You also associated this reaction set with a fluid package and attached it to a conversion reactor

unit. Your HYSYS simulation of this reactor determined the heat duty needed to maintain the

endothermic reaction at isothermal conditions. In this tutorial, you will add a Gibbs reactor unit

to this flowsheet and compare its simulation results to those from the conversion reactor. You

will begin with the existing file named equil.hsc located on the network file server. The pre-

defined simulation in this file is set for the Peng-Robinson-Stryjeck-Vera (PRSV) fluid package

with four chemical components and a heater process unit, named E1, and a conversion reactorunit, named R1.

In most reactor units, catalysts are used to increase the rate of reaction; that is, the speed

of converting the reactants into products. Different catalysts when placed in a fixed reactor

volume will produce a range of conversions for the reactants; that is, some catalysts will do better

then others with respect to conversion. In Tutorial 2.6, you used an experimentally-determined

molar conversion for a specific catalyst at a given temperature and pressure of operation.

Thermodynamic equilibrium sets a theoretical limit on the extent to which reactants can

be converted into products, and this limit cannot be changed by catalysts. This limit is the best

you could expect, provided you could find the right catalyst to achieve it. The HYSYS Gibbs

reaction model predicts thermodynamic equilibrium by minimizing the total Gibbs free energy ofthe reacting system, and it does so without having to know the reaction stoichiometry, because it

uses atom balances instead of mole balances. When you add a Gibbs reactor to a HYSYS

simulation, you can determine the theoretical conversion limit for any reaction. This tutorial is

divided into six sections—start the HYSYS program, open an existing simulation file, copy a

reactor feed stream, add a Gibbs reactor to the flowsheet, specify the reactor outlet conditions,




preference settings were last saved in your default preference file. You shouldalways check these default preferences before you begin your simulation work.









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Tutorial 2.7

in the upper-right part of the HYSYS desktop. the full area of the monitor screen.


bar.



.3. Select the Variables/Units page.


if necessary.


Variables view.







B.

Open an existing simulation file.


for you to access. It is called equil.hsc. This file is the basis for this tutorial that

simulates an equilibrium reactor using the Gibbs reaction model. Proceed as

follows to open equil.hsc and save a copy of it:



or









Manual/Chap 2.

To find the HYSYS simulation file equil.hsc


Manual folder.

3. Double-click on the file named equil.hsc,

or



Process Flow Diagram (PFD) window and the

Workbook window appear in the HYSYS

desktop.







or







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Tutorial 2.7

Note that





larger.

After you have finished your simulation work,you can drag the file from the Windows



To save your equil.hsc simulation file.

C. Copy a reactor feed stream.

To compare the simulation results of the conversion reactor and the Gibbs

reactor, the two reactors must have the same feed stream conditions. TheHYSYS copy stream utility allows you to retrieve the conditions of one stream to

set the conditions of another stream. Proceed as follows to create a new feed

stream S2g for the Gibbs reactor and assign it the same conditions as those of

stream S2, the conversion reactor feed.

1. Click the middle Maximize Window icon

in the upper-right part of the PFD window.

Press the <F4> function key on the keyboard;


in the PFD window.

Note that

To expand the PFD – Case(Main) window to

fit the full area of the HYSYS desktop.



operations.

Moving the cursor over a palette icon willreveal its name.

2. Click the blue Material Stream icon in the

Object Palette, move the cursor into the PFD

about 2 inches below the label QR1, and click.

Note that


The stream’s process state has not yet been

specified, so the stream icon is light blue.

3. Double-click on the stream 1 icon in the PFD.

Select the Worksheet/Conditions page, if

necessary.

Note that


To display the vapor fraction, temperature,

pressure, molar flow, etc. of the stream.

The “object status” area of this window has a

yellow “Unknown Compositions” message,

implying that you must supply more data.

4. Enter S2g in the Stream Name cell of stream 1



value of 1 to S2g.

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Tutorial 2.7

5. Click on the Define From Other Stream…

button.


Streams area.




To choose the conditions of stream S2 to be

copied into stream S2g. The object status at

the bottom of the property window for streamS2g turns green and shows OK, indicating the

new stream now has been determined.

To close the property window of stream S2g.


Click the PFD icon on the button bar.

To view the stream conditions. Stream S2g is

at the same temperature, pressure, flow, and

composition as stream S2.

To view the process flow diagram.

D. Add a Gibbs reactor to the flowsheet.

Now that you have created a feed stream for the reactor, you will now add a

Gibbs reactor vessel to the simulation. The stream S2g will be fed to reactor R1g

to create a product stream named S3g. The reactor requires a heat duty stream

named QR1g. Proceed as follows:

1. Click the General Reactors icon in the Object

Palette.

Click the Gibbs Reactor icon in the sub-

palette; move the cursor into the PFD just tothe right of stream S2g; and click the mouse

button.


To open a small, sub-palette window that

contains three general reactor icons.

To add the GIBBS REACTOR unit

operation into the PFD window. The reactoricon is labeled with GBR-100.

2. Double click on GBR-100 icon in the PFD.

Note that





visible in the reactor property window.

A property window always shows the statusof its object (red for missing information, yellow




green.


To view the Connections page of GBR-100.

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Tutorial 2.7

Enter R1g in the Name cell of this page;


Note that


of GBR-100 to R1g. HYSYS assigns a

default name to every stream and unit

operation that you create.


stream to reactor R1g.

4. Click in the topmost Inlets cell and select S2g



or

Enter S2g in this cell.

Note that

To connect stream S2g as the feed stream to

the Gibbs reactor operation. HYSYS allows

multiple feed streams to reactors. Your

simulation requires only one feed stream.

The red object status of “Requires a product


outlet stream to reactor R1g.

5. Enter S3g in the Vapour Outlet cell.

Enter S4g in the Liquid Outlet cell.

Note that

Note that

To define stream S3g as the product streamleaving the reactor process operation.

Stream S3g did not previously exist in the


S3g creates a new process stream called S3g.

To define stream S4g as the liquid stream.

Gibbs reactors in a HYSYS simulation may

produce a vapor outlet stream, liquid outlet

stream, or both. In your simulation, the

reaction is in the vapor phase only; however,

HYSYS requires that a liquid product stream be defined.

The green object status of “OK” implies that

HYSYS had sufficient information to simulate

Gibbs R1g as an adiabatic reactor, one

without an energy stream.

6. Enter QR1g in the Energy cell. To define stream QR1g as the energy stream



Note that

Energy stream QR1g did not previously exist

in the flowsheet. Thus, naming the rectorduty creates a new energy stream called

QR1g. You picked the name QR1g because

symbol Q stands for heat duty and “R1g”

implies that this Q is associated with unit

operation R1g.



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Tutorial 2.7

Note that

Note that


reactor (i.e., same inlet and outlet temperature),

and it requires a duty stream.

The yellow object status of “Unknown Duty”

implies that you must supply additional data before HYSYS can simulate reactor R1g.



Ψ Δ ΨS g R g R g S g S g S g

P Q gibbs T P3 1 1 2 3 3

, , , ,=

where gibbs is the function whose variables




temperature, pressure, flow rate, and chemicalcomposition of Stream i.


Click to the left of the stream S2g icon.

Click the Zoom All button in lower left of the


Note that

To close the property window of reactor R1g.

To de-select the items around the reactor R1g.


the PFD window.

The PFD now contains the reactor R1g icon

with a dark blue inlet stream S2g, a light blue

outlet stream S3g, and a light maroon duty

stream QR1g.







The S3g and QR1g icons appear in light

colors because HYSYS can not calculate them

until you specify two more conditions, as

implied by the mathematical function in Step

6 above.

E. Specify the reactor outlet conditions.

You have added a Gibbs reactor to your simulation and connected the feed,


from the HYSYS simulation of the heater E1 operation. Now you will specify

the product stream temperature and pressure. The stoichiometry for the cumene

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Tutorial 2.7

reaction is not needed by the Gibbs reactor, because it minimize the total Gibbs

free energy using the atom balances. Once you have made these specifications,

HYSYS will automatically calculate the reactor’s pressure drop and heat duty.

Proceed as follows:

1. Double-click on the R1g icon in the PFD.

Select the Reactions/Overall page.

Click on Gibbs Reactions Only in the

Reactor Type area, if necessary.

Note that


To view the Reactor Type area of this page.

You must define the reactor type for R1g.

To select the Gibbs reaction model when the

reaction stoichiometry is not known.

A Gibbs reactor can also be used with

equilibrium reactions, or with no reactions so

that the vessel acts like a separator.


near the bottom of the window implies that

you must supply additional data before

HYSYS can simulate reactor R1g.


page.

Click in Delta P cell, then hit <Delete> key.

Note that

To view the Design/Parameters page in the

Gibbs reactor R1g window.

To de-activate its blue value of 0.0000 kPa to

a blank value. By this action, you inform

HYSYS to calculate the Delta P value.

Since you will be specifying the reactor outlet

stream pressure, HYSYS will then calculate

the pressure drop (Delta P) from the known

values of the feed and outlet stream pressures.


page.




Note that





connected to reactor R1g.

Stream S2g is fully determined but material

stream S3g and energy stream QR1g are not.

Stream QR1g has one blue empty cell, whilestream S3g has nine. A blue empty cell

implies you can input a value in that cell,

except for the last four in stream S3g.

HYSYS can only enter values in these cells.

Of the first four blue empty cells, you must

supply values for any two before HYSYS will

do the calculations.

4. Enter 350 °C in the Temperature cell of S3g. To specify a temperature for the outlet stream.

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Tutorial 2.7

Enter 3025 kPa in the Pressure cell of S3g.

Note that

Note that





The remaining cells of streams QR1g and S3g



page.

Note that




the calculated reactor duty is –7.719e6 kJ/h.




variables: pressure drop, heat duty, outletvapor fraction, outlet temperature, and outlet

pressure.


Note that

To close the property window of unit

operation R1g. The reactor and stream icons

in the PFD are now dark colors, indicating the


solved, and all stream and reactor variables

are determined.

You have just completed the simulation for

the Gibbs reactor. You will now compare its

conversion for propene to the 83% used in theconversion reactor of Tutorial 2.6. But first,

you will re-format the Workbook to facilitate

this comparison.


Choose Workbook/Setup… from the menu

bar.


Click the Add… button in the Variables area.

-----------------------------------------

Click Comp Molar Flow in Variable area,



Click the Close button in the Setup window.

To access the Workbook window.




To open the Select Variable(s) for Main

window.

To add all the component molar flows to the

Streams page of the workbook.


To return to the Workbook window. Now,

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Tutorial 2.7

-----------------------------------------

Choose Workbook/Order/Hide Objects…

from the menu bar.

Click button Ascending in the Sorting area.

Use the Down arrow in the Move Selection

area.


-----------------------------------------

Drag the lower right corner of the Workbook

window either right, left, or down.

Note that

all stream component molar flow rates appear

in the workbook.

To open the Order/Hide/Reveal Objects

window and change the organization of theworkbook.

To re-organize the material and energy

streams in ascending order based on their

names.

To move item S4 in the list down to just

before S4g.

To return to the Workbook window.

To have streams S2, S3, S2g, and S3g appear

contiguously across the Workbook window.

You are now ready to compare the conversion

reactor (streams S2 and S3) to the Gibbs reactor

(streams S2g and S3g).

8. Compare feed stream S2 to product stream S3

for the conversion reactor.

To make the following observations about the

component molar flow rates:

• those of benzene and propene decrease

which is the case for the two reactants,

• that of propane is constant which is the

case for an inert compound,• that of cumene increases as expected

which is the case for the product.

These observations confirm our expectations.

Compare feed stream S2g to product stream S3g

for the Gibbs reactor.



• those of benzene and propane increase

which is unexpected, since one is a

reactant and the other is an inert,

• that of propene decrease to a very low

amount,

• that of cumene increases somewhat.

The first observation is counter intuitive,

while the last two exhibited correct trends.

Why does the Gibbs reactor give unexpected

simulation results?

The Gibbs reactor model assumes that all

chemical components in the feed stream are

present in the equilibrium reaction, when the

total Gibbs free energy of the reacting system

is minimized. Because the inert of propane is

present, it causes the erroneous results.

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Tutorial 2.7

Therefore, the Gibbs reactor must be

simulated with only benzene, propene, and

cumene present in the HYSYS fluid package.

9. As an experiment, run HYSYS to determinethe molar conversion of propene for a Gibbs

reactor where its feed stream contains only

benzene, propene, and cumene.

You will need to start with file gibbs.hsc andmodify it. If you like, proceed as follows:

1. remove propane from fluid package;

2. do not define a reaction set;

3. return to the simulation environment

in the HOLDING mode.

4. open the Workbook window.

5. change the propene and benzene

flows to 1 kgmol/h each, giving a

total flow of 2 kgmol/h;

6. enter 350°C and 3025 kPa for the

product stream S3g;

7. click the green GO icon in the button

bar to have the calculations done.You should get a propene conversion, based

on the Gibbs model, of 94.1 molar percent.

This 94.1% is the equilibrium limit for the

reaction. If you could find the right catalyst,

the best you could expect for the propene

conversion is this theoretical limit.

Note that When a Gibbs reactor predicts an equilibrium

limit near 100%, the reaction is considered

irreversible; that is, it goes to completion.

F. Close the simulation case.

You will close the file of your simulation case and then possibly exit HYSYS.

Proceed as follows:



or

Press the <Ctrl><Z> keys simultaneously,



not save it.


or




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Tutorial 2.8

Kinetic Model and a Plug Flow Reactor

In Tutorial 2.6, you conducted a HYSYS simulation on an isothermal reactor using a

conversion reaction model for the following stoichiometric equation:

C3H6 + C6H6 → C9H12

propene benzene cumene

You specified a molar propene conversion of 83%, and propane was present in the reactor feed as

an inert compound. In Tutorial 2.7, you did another simulation on the same isothermal reactor,

but you used the Gibbs reaction model to predict an equilibrium propene conversion of 94.1% for

the above reaction. This conversion represents the best you could expect; it is the theoretical

limit on the propene conversion.

In this tutorial, you will again study the isothermal reaction, but you will simulate it using

a plug flow reactor with a kinetic model and then compare your results to those from Tutorials 2.6

and 2.7. An experimentally-determined kinetic model for a particular catalyst is used to predictthe behavior of a specific reaction to changes in temperature and pressure. You will begin with

the existing file named kinetic.hsc located on the network file server. The pre-defined simulation

in this file is set for the Peng-Robinson-Stryjeck-Vera (PRSV) fluid package with four chemical

components and a heater process unit, named E1, and a conversion reactor unit, named R1.

This tutorial is divided into seven sections—start the HYSYS program, open an existing

simulation file, copy a reactor feed stream, add a plug flow reactor to the flowsheet, add a kinetic

reaction set to the fluid package, specify the reactor parameters and outlet conditions, and close

the simulation case. To proceed, you must be familiar with the material in Tutorials 2.6 and 2.7.

A.

Start the HYSYS program.















bar.






Variables view.


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Tutorial 2.8

if necessary. units— °C, kPa, kgmole/h, kJ, etc.







for you to access. It is called kinetic.hsc. This file is the basis for this tutorial

that simulates an isothermal reaction using a plug flow reactor with a kinetic

model. Proceed as follows to open kinetic.hsc and save a copy of it:



or









Manual/Chap 2.

To find the HYSYS simulation file

kinetic.hsc on the network file server in the

HYSYS Manual folder.

3. Double-click on the file named kinetic.hsc,

or





desktop.








or


Note that








to transfer data over the network. Simulationspeed becomes important as your file becomes

larger.





To save your kinetic.hsc simulation file.

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Tutorial 2.8

C. Copy a reactor feed stream.

To compare the simulation results of the conversion reactor and the plug flow

reactor, the two reactors must have the same feed stream conditions. The

HYSYS copy stream utility allows you to retrieve the conditions of one stream to

set the conditions of another stream. Proceed as follows to create a new feed

stream S2k for the plug flow reactor and assign it the same conditions as those of

stream S2, the conversion reactor feed.



Press the <F4> function key on the keyboard;


in the PFD window.

Note that

To expand the PFD – Case(Main) window to

fit the full area of the HYSYS desktop.



operations.


reveal its name.

2. Click the blue Material Stream icon in the

Object Palette, move the cursor into the PFD

about 2 inches below the label QR1, and click.

Note that


The stream’s process state has not yet been

specified, so the stream icon is light blue.

3. Double-click on the stream 1 icon in the PFD.

Select the Worksheet/Conditions page, ifnecessary.

Note that


To display the vapor fraction, temperature, pressure, molar flow, etc. of the stream.

The “object status” area of this window has a

yellow “Unknown Compositions” message,

implying that you must supply more data.

4. Enter S2k in Stream Name cell of stream 1;



value of 1 to S2k.

5. Click the Define From Other Stream…

button.


Streams.




To choose the conditions of stream S2 to becopied into stream S2k. The object status at

the bottom of the property window for stream

S2k turns green and shows OK, indicating the

new stream now has been determined.

To close the property window of stream S2k.

6. Click the Workbook icon on the button bar. To view the stream conditions. Stream S2k is

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Tutorial 2.8

Click the PFD icon on the button bar.

at the same temperature, pressure, flow, and

composition as stream S2.

To view the process flow diagram.

D. Add a plug flow reactor to the flowsheet.

Now that you have created a feed stream for the reactor, you will now add a plug

flow reactor (PFR ) to the simulation. The stream S2g will be fed to reactor R1k

to create a product stream named S3k. The reactor requires a heat duty stream

named QR1k. Proceed as follows:

1. Click the Plug Flow Reactor icon in the

Object Palette; move the cursor into the PFD

just to the right of stream S2k; and click the

mouse button.


To add the PLUG FLOW REACTOR unit

operation into the PFD window. The reactor

icon is labeled with PFR-100.

2. Double click on the PFR-100 icon in the PFD.

Note that





visible in the PFR-100 property window for

the reactor.

A property window always shows the status

of its object (red for missing information, yellowfor a warning message, and green for OK ).



green.


Enter R1k in the Name cell of this page;


Note that

To view the Connections page of PFR-100.


of PFR-100 to R1g. HYSYS assigns a

default name to every stream and unit

operation that you create.


stream to reactor R1k.

4. Click in the topmost Inlet cell and select S2k



or

Enter S2k in this cell.

To connect stream S2k as the feed stream to

the plug flow reactor operation. HYSYS

allows multiple feed streams to reactors.

Your simulation requires only one feed

stream.

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Tutorial 2.8

Note that The red object status of “Requires a product


outlet stream to reactor R1k.

5. Enter S3k in the Outlet cell.

Note that

To define stream S3k as the product streamleaving the reactor process operation.

Stream S3k did not previously exist in the


S3k creates a new process stream called S3k.



data before HYSYS can simulate reactor R1k.

6. Enter QR1k in the Energy cell.

Note that

Note that

Note that

To define stream QR1k as the energy stream



Energy stream QR1k did not previously exist

in the flowsheet. Thus, naming the rector

duty creates a new energy stream called

QR1k. You picked the name QR1k because

symbol Q stands for heat duty and “R1k”

implies that this Q is associated with unit

operation R1k.




reactor (i.e., same inlet and outlet temperature),and it requires a duty stream.

The red object status of “R equires a Reaction


data before HYSYS can simulate reactor R1k.



Ψ Δ ΨS k R k R k S k S k S k

P Q plugr T P3 1 1 2 3 3

, , , ,=

where plugr is the function whose variables


those variables on the right are specified.

Although not shown, dimensional data for the

reactor must be supplied. The vector Ψi is a

short notation to represent the temperature,

pressure, flow rate, and chemical composition

of Stream i.

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Tutorial 2.8


Click to the left of the stream S2k icon.



Note that

To close the property window of reactor R1k.

To de-select the items around the reactor R1k.


the PFD window.

The PFD now contains the reactor R1k icon

with a dark blue inlet stream S2k, a light blue

outlet stream S3k, and a light maroon duty

stream QR1k.







The S3k and QR1k icons appear in light

colors because HYSYS can not calculate them

until you specify two more conditions, as

implied by the mathematical function in Step

6 above.

E. Add a kinetic reaction set to the fluid package.

The plug flow reactor requires a kinetic model in order to calculate the material

and energy requirements. This kinetic model is specified as a reaction set in thefluid package. For this simulation, the following kinetic model describes the

reaction rate for the formation of cumene:

r k c cCU PY BZ

=

⎟⎟ ⎠

⎞⎜⎜⎝

⎛ −=

T R

E Ak exp

where r CU is the cumene formation rate in kgmol/m3 s.

k is the Arrhenius temperature dependency in kgmol/m3 s.

cPY is the molar concentration of proplyene ( propene) in kgmol/m3.

c BZ is the molar concentration of benzene in kgmol/m3.

A is is the reaction constant in kgmol/m3 s.

E is is the reaction activation energy in kJ/kgmol.

R is the gas constant in kJ/kgmol K.

T is the reaction temperature in K.

For a specific catalyst and the cumene reaction, A is 3500 kgmol/m3 s, and E is

56000 kJ/kgmol. A new reaction set must be created that contains this kinetic

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Tutorial 2.8

model. Proceed as follows to add this kinetic model to the current fluid package

of kinetic.hsc, which currently contains a conversion model:

1. Click on the Enter Basis Environment icon in

the button bar.

Click on the Reactions tab, if necessary.


window that contains tabbed views.

To view the Reactions page. This page is

where you can define an unlimited number of

reactions and collect combinations of these

reactions into reaction sets.

2. Select PY Conversion in the Reactions area

and then click the Copy Rxn… button.

Click PY Conversion in the Copy Reactions

window and then click Kinetic in the New

Reaction Type area

Click the Copy Reaction… button.

.

Enter PY Kinetic in the Name cell at the

bottom of the window.

Note that

To open the Copy Reactions window and

create a kinetic reaction model, based of off

the PY Conversion model.

To select it as the reaction model to be copied

and then choose kinetic as the new reaction

model.

To open the Kinetic Reaction window. The

component and stoichiometic coefficients

have been automatically retrieved for you by

HYSYS from the PY Conversion model.

To give the kinetic model for the cumene

reaction a unique identification.

The status area of the Kinetic Reaction

window currently is a red “Not Ready”,

meaning that you must supply more reaction

information.

3. Enter 1 in the Forward Order cell for propene.

Enter 1 in the Forward Order cell for benzene.

Enter 0 in the Forward Order cell for cumene.

Note that

Note that

Note that

To specify the exponents on the component

composition variables in the kinetic model.

The propene and benzene exponents on

concentration are one, while that of cumene is

zero.

The Reverse Order column is left empty

because the kinetic model for cumene

formation assumes an irreversible reaction.

The Forward Order and Reverse Order

columns allow you to define complex kinetic

models, ones whose exponents oncomposition variables are other then 1.

The status area is still a red “Not Ready”,

meaning you must supply a kinetic basis.

4. Click on the Basis tab. To view the Basis page of the Kinetic

Reaction window.

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Tutorial 2.8

Click in the Basis cell and select Molar Concn

using the drop-down menu of▼.

Note that

Enter Propene in the Base Component cell,

using the drop-down menu of▼, if necessary.

Note that

Click in the Rxn Phase cell and select

VaporPhase using the drop-down menu of▼.

Note that

To specify molar concentration for the

composition variables in the kinetic model.

The Basis Units are kgmole/m3, and the Rate

Units are kgmole/m3

s for the kinetic model inthis tutorial. If these units where different,

you would use the two drop-down menus to

change them.

To specify propene as the base component in

the kinetic reaction model.

The base component is the limiting reactant in

a chemical reaction. Since stream S2 contains

213.6 kgmol/h of benzene and 110.5 kgmol/h

of propene, propene is the limiting reactant.

To specify that the reaction occurs in thevapor phase only. Both the reactants and

product will be in the vapor phase.

The status area is still a red “Not Ready”,

meaning you must supply the kinetic

parameters, constants in the kinetic model.

5. Click on the Parameters tab.

Enter 3500 in the A cell of the Forward

Reaction area.

Enter 56000 in the E cell of the Forward

Reaction area.

Note that

Note that



Note that

To view the Parameters page of the Kinetic

Reaction window.

To specify the reaction constant in the kinetic

model. Its units are those of the Rate Units on

the Basis page.

To specify the activation energy in the kinetic

model. Its units are kJ/kgmole.

The Reverse Reaction area is left empty

because your kinetic model is for an

irreversible reaction.

The status area in the Kinetic Reaction

window is now a green “Ready” message.

You have just completed the specifications for

the kinetic reaction model.

To close the Kinetic Reaction window.

To close the Copy Reactions window and

return to the Reactions page of the Simulation

Basis Manager.

The Reactions area in the middle of the

Reactions page lists PY Conversion as the

first reaction and PY Kinetic as the second

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Tutorial 2.8

Note that

Note that

reaction in the Reaction Manager.

All reactions in the Reactions area are placed

automatically into the Global Rxn Set by

HYSYS. This set is listed in the Reaction

Sets area at the right side of the Reactions page. If you were to view this global set, you

would find the conversion reaction on the

Active List and the kinetic reaction on the

Inactive List. This means the Global Rxn Set

is configured for a conversion reaction model

only.

For different reactions to be carried out in

different process units of a process flow

diagram (PFD), new reaction sets need to be

created in the Reaction Sets area of the

Reaction Manager. Since you need only a

kinetic reaction for this tutorial simulation,you will define a new reaction set for it.

6. Click the Add Set… button in the Reaction

Sets area.

Enter Kinetic Rxn Set in the Name cell.

Click in the first cell of the Active List column

and select PY Kinetic from the drop-down

menu of▼ near the top right of the window.


Note that

To open the Reaction Set window and define

a new set that will contain the kinetic model.

To give this reaction set a descriptive name.

To include the kinetic reaction model in this

reaction set.

To close the Reaction Set window and return

to the Reactions page of the Simulation BasisManager.

The Kinetic Rxn Set now appears as the

second set in the Reaction Sets list.

7. Click the Kinetic Rxn Set in the Reaction Sets

list, if necessary.

Click the Add to FP button at the bottom of the

Reaction Sets area.

Click Basis-1 in the Add ‘Kinetic Rxn Set’

window, and then click the Add Set to Fluid

Package button.

Note that

To select it so that you can connect it to a

fluid package.

To associate the kinetic reaction set with the

current fluid package. The reaction set must

be added to the fluid package in order for the

reactions to be used in a process unit of aflowsheet.

To add the kinetic reaction set to the Basis-1

fluid package.

Basis-1 now appears under the Associated

Fluid Packages of the Reaction Sets area.

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Tutorial 2.8




contains the PFD and workbook windows.

You have just completed the addition of a

kinetic reaction model to your fluid package.

F. Specify reactor parameters and outlet conditions.

You have added a plug flow reactor to your simulation and connected the feed,


from the HYSYS simulation of the heater E1 operation. You must now connect

the kinetic reaction set for cumene to the reactor, then provide size information

for the reactor, and finally specify the product stream temperature and pressure.

Once you have made these specifications, HYSYS will automatically calculate

the reactor’s pressure drop and heat duty. The calculations for reactor R1k involve the numerical solution of a set of ordinary differential equations for the

material and energy balances. Proceed as follows:

1. Double-click on the R1k icon in the PFD.

Select the Reactions/Overall page.

Click the cursor in the Reaction Set cell of the

Reaction Info area.

Select Kinetic Rxn Set from the drop-down

menu of▼ to the right of this cell.

Select the Reactions/Details page.

Click the View Reaction… button in the

Reaction Details area.

Note that


Note that


To view the Reaction Info area of this page.

You must attach a reaction set to the plug

flow reactor R1k.

To get the vertical bar in that cell.

To connect the kinetic reaction set to reactor

R1k for the cumene reaction.

To view the information in the Reaction

Details area of this page.

To view the Kinetic Reaction window named

PY Kinetic.

The status area of this window currently is a

green Ready, meaning that the kinetic

reaction set has been properly defined. If any

reaction information were incomplete, then

this status area would not be green.

To close the Kinetic Reaction window and

return to the Reactions/Details page.

The red object status of “Unknown

Dimensions” near the bottom of this page

implies that you must supply reactor

dimensions before HYSYS can simulate R1k.

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Tutorial 2.8

2. Select the Rating/Sizing page.

Enter 8 meters in the Length cell;

Enter 1.5 meters in the Diameter cell;Enter 1 in the Number of Tubes cell.

Note that

Note that

To view the Tube Dimensions area for the

plug flow reactor.

To specify the tube dimensions of the reactor.

In this tutorial, the PFR is a single cylindricalvessel with a length of 8 meters and a

diameter of 1.5 meters.

Once you have specified these parameters,

HYSYS automatically calculates the Total

Volume and Void Volume. Do not change

the default values for Wall Thickness and

Void Fraction.


near the bottom of the window implies that

you must supply additional data before

HYSYS can simulate reactor R1k.


page.




Note that





connected to reactor R1k.

Stream S2k is fully determined but material

stream S3k and energy stream QR1k are not.

Stream QR1k has one blue empty cell, while

stream S3k has nine. A blue empty cell

implies you can input a value in that cell,except for the last four in stream S3k.

HYSYS can only enter values in these cells.

Of the first four blue empty cells, you must

supply values for any two before HYSYS will

do the calculations.

4. Enter 350 °C in the Temperature cell of S3k.

Enter 3025 kPa in the Pressure cell of S3k.

Note that

Note that

To specify a temperature for the outlet stream.


With these two variables specified, HYSYS

begins to solve numerically the ordinary

differential equations for the material andenergy balances, which may take some time to

complete. Once the solution is completed, the

object status area turns green, which indicates

that HYSYS did the calculation successfully.

The remaining cells of streams QR1k and

S3k are now filled with black, calculated

values.

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Tutorial 2.8


page.

Note that




the calculated reactor duty is –1.088e+7 kJ/h.




variables: pressure drop, heat duty, outlet

vapor fraction, outlet temperature, and outlet

pressure. You can also adjust the dimension

variables for the plug flow reactor.


Note that

To close the property window of unit

operation R1k. The reactor and stream icons

in the PFD are now dark colors, indicating the


solved, and all stream and reactor variablesare determined.

You have just completed the simulation for

the plug flow reactor. You will now compare

its conversion for propene to the 83% used in

the conversion reactor of Tutorial 2.6 and to

the 94.1% predicted by minimizing the Gibbs

free energy in Tutorial 2.7. But first, you will

re-format the Workbook to facilitate this

comparison.


Choose Workbook/Setup… from the menu

bar.


Click the Add… button in the Variables area.

-----------------------------------------

Click Comp Molar Flow in Variable area,



Click the Close button in the Setup window.

-----------------------------------------

Choose Workbook/Order/Hide Objects…

from the menu bar.

To access the Workbook window.




To open the Select Variable(s) for Main

window.

To add all the component molar flows to the

Streams page of the workbook.


To return to the Workbook window. Now,

all stream component molar flow rates appear

in the workbook.

To open the Organize Workbook Objects

window and change the organization of the

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Tutorial 2.8

Click button Ascending near the right side of

the Organize Workbook window.

Use the Down arrow in the Move Selection

area.


-----------------------------------------

Drag the lower right corner of the Workbook

window either right, left, or down.

Note that

workbook.

To re-organize the material and energy

streams in ascending order based on their

names.

To move item S4 in the list down to the end of

that list.

To return to the Workbook window.

To have streams S2, S3, S2k, and S3k appear

contiguously across the Workbook window.

You are now ready to compare the conversion

reactor (streams S2 and S3) to the plug flow

reactor (streams S2k and S3k).

8. Compare feed stream S2 to product stream S3

for the conversion reactor.






case for an inert compound,

• that of cumene increases as expected


The propane conversion is (110.5 – 18.8) /110.5,

giving a value of 83%. These observations

confirm our expectations.

Compare feed stream S2k to product stream S3k

for the plug flow reactor.


com ponent molar flow rates:




case for an inert compound,

• that of cumene increases as expected


The propane conversion is (110.5 – 1.8) /110.5,

giving a value of 98%. These observations

are similar to those for the conversion reactor,

except the propene conversion is higher for

the plug flow reactor.

Why does the plug flow reactor give a much

higher conversion, one greater than the Gibbs

theoretical limit of 94.1%?

The mathematical model for the HYSYS plug

flow reactor does not incorporate a limit

check on the propene conversion. If you

made the tube length long enough, you could

get the plug flow reactor to predict a 100%

conversion.

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Tutorial 2.8

Therefore, any tube length beyond that length

which gives 94.1% propene conversion is

wasted and costly reactor space. No addition

conversion will occur in this reactor space.

9. As an experiment, change the tube length in the plug flow reactor until you get a propene

conversion of about 94 mole percent.

You should get a tube length of about 5.7meters. As you learned from Tutorial 2.7, this

94% is the equilibrium limit for the reaction.

It is the best conversion you could expect for

the reaction of propene and benzene to form

cumene.



Proceed as follows:



or




not save it.


or




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Tutorial 2.9

PFD Manipulation Tools

The focus of this tutorial is the HYSYS Process Flow Diagram (PFD). You can use the

PFD to satisfy a number of functions while doing a process simulation. In addition to a graphical

representation, you can build a flowsheet within the PFD using the mouse to install and connectobjects. A full set of manipulation tools is associated with the PFD to allow you to reposition

process streams and operations, resize icons, reroute streams, and create documentation text. All

of these tools are designed to simplify your development of a clear and concise graphical process

representation. You can use these tools to prepare your documentation for your solutions to the

assignments in Chapters 3 and 4.

In this tutorial, you will learn how to use effectively some of the PFD manipulation tools.

You will begin with the existing file named pfdtools.hsc located on the network file server. The

pre-defined simulation in this file is set for the Peng-Robinson-Stryjeck-Vera (PRSV) fluid

package with four chemical components ( benzene, propylene, propane, and cumene) and a heater process

unit, named E1, and a conversion reactor unit, named R1. The reactor converts propylene and

benzene to cumene with propane acting as an inert compound.

This tutorial is divided into ten sections—start the HYSYS program, open an existing

simulation file, zoom flowsheet in and out, orient some PFD icons, move some icon labels, view

some operating conditions, add some documentation text, connect and disconnect PFD objects,

copy a PFD to a Word document, and close the simulation case. To proceed, you must be

familiar with the material in Tutorials 2.4 and 2.6.



preference settings were last saved in your default preference file. You shouldalways check these default preferences before you begin your simulation work.












bar.





if necessary.


Variables view.



4. Click the Close button; that is, the X button in To close the Session Preferences window

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Tutorial 2.9

the upper right corner of the window. and return to the HYSYS desktop.



for you to access. It is called pfdtools.hsc. This file is the basis for this tutorial

that demonstrates how you can manipulate the process flow diagram. Proceed as

follows to open pfdtools.hsc and save a copy of it:



or









Manual/Chap 2.

To find the HYSYS simulation file

pfdtools.hsc on the network file server in the

HYSYS Manual folder.

3. Double-click on the file named pfdtools.hsc,

or





desktop.







or


Note that










larger.





To save your pfdtools.hsc simulation file.

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Tutorial 2.9

C. Zoom flowsheet in and out.

The existing HYSYS file pfdtools.hsc shows the flowsheet as a small section in

the PFD window. The zoom functions allow you to enlarge or shrink the

flowsheet in order to fit the PFD window. This section explains the different

methods for zooming in and out on the process flowsheet.

1. Click the zoom in icon of + in the bottom left

corner of the PFD.

Click the zoom in icon a few more times.

To zoom in on the flowsheet. This will

enlarge the streams and unit operation icons.

To make the flowsheet fill more of the PFD

window.

2. Click the zoom out icon of - in the bottom left

corner of the PFD.

Click the zoom out icon a few more times.

To zoom out in the flowsheet. This will

shrink the streams and unit operation icons.

To make the flowsheet smaller in the PFD

window.

3. Place the cross hairs of the cursor over the

letter C in reactor R1 and hit the period key on

the keyboard.

To center the reactor R1 in the middle of the

PFD window. This action is useful when you

want to focus on a specific part of a

flowsheet.



Note that


window.

Any time the Zoom All icon is used, HYSYS

will move and enlarge or shrink the flowsheet

to exactly fill the PFD window.

4. Click the drag zoom icon in the button bar at

the top of the PFD window.

Note that

Click and drag in the PFD to create a box that

surrounds the icons for streams S2, S3, QR1

and reactor R1, and then release the mouse

button.

To enter the zoom mode. The cursor will now

appear with a magnifying glass icon.

You can use this cursor to click and drag a

box around a part of the flowsheet. Once you

release the mouse button, HYSYS will then

zoom in on the icons in the box.

To choose the reactor and its attached streams.

HYSYS will automatically zoom in on the

area included in the box you have just

outlined.



Note that

To place again the entire flowsheet in the

PFD window.

In the PFD, the material stream S2 is pointing

in an awkward direction and the label for the

energy stream QE1 is also in an awkward

position. You will now use some interactive

tools to manipulate icons on the PFD.

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Tutorial 2.9

D. Orient some PFD icons.

HYSYS adds stream and unit operation icons to the PFD in a certain

orientation ⎯

facing left, right, up or down. Usually the default orientationcreates a flowsheet with streams flowing from left to right in a more or less

straight line. The user may want to change the icon orientations. This section

shows you how to change the icon orientation of stream S2 using the transform

function and how to move a collection of icons on the PFD.

1. Object inspect stream S2 in the PFD flowsheet;i.e., position cursor on an object and press the secondary

(usually right) mouse button once.

Note that

To view the drop-down menu of options

associated with object manipulation.

The stream S2 icon faces to the left in the

PFD. You will reverse its orientation.

2. Select Transform/Rotate by 180 in the drop-

down menu for object S2.

Note that

To flip the icon for stream S2 horizontally.

Stream S2 now flows from left to right.

Streams S1 and S2 do not fall on the same

horizontal line. You will use the horizontal

cross hair of the cursor to move stream S2 so

that it is in line with stream S1.

3. Place the cursor on the stream S2 icon and

have its horizontal cross hair cover the blue

stream line.

Click and drag the stream S2 icon down so that

the horizontal cross hair covers the blue stream

line of stream S1.

Note that

To get a portion of the horizontal cross hair to

turn white. This action insures that you are on

the centerline of the stream S2 icon.

To position stream S2 in line horizontally

with stream S1.

Stream S1, heater E1, and stream S2 all line

up; however, they are not in line with reactor

R1. You will collectively move these three

objects next.

4. Click and drag in the PFD to create a box that

surrounds the icons for S1, E1, QE1 and S2,

and then release the mouse button.

Note that

Place the cursor on the heater E1 icon and have

its horizontal cross hair cover the blue stream

lines.

Click and drag the collection of icons down so

that the horizontal cross hair covers the blue

To select these four icons as a collective

group. Selection of an icon is indicated by a

white rectangle.

An alternative way to select multiple icons as

a collection is to click on the first icon and

then hold down the <Shift> key as youcontinue selecting the remaining icons.

To insure that you are on the centerline of the

three objects—stream S1, heater E1, and

stream S2.

To position the collection of four icons— S1,

E1, QE1, and S2 —relative to reactor R1.

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Tutorial 2.9

stream line for S2 entering the reactor R1.

5. Move the energy stream QE1 icon above the

blue line of stream S2.

Note that

To line it up with the dark maroon arrow that

enters process unit E1. You do this move

based on what you learned in Steps 3 and 4.

The flowsheet in the PFD window has the

appearance of a clear and concise graphical

presentation, except for labels QE1 and R1.

You have this burning desire to move label

QE1 above the energy stream icon and to

place label R1 inside of the reactor icon.

E. Move some icon labels.

HYSYS labels each icon in the PFD with either a default name or the namespecified by the user. The labels are placed by default next to or under the icon.

This section shows you how to move some icon labels.

1. Object inspect energy stream QE1 and select

Move/Size Label from the drop-down menu.

To select label QE1 so that you can move it.

A white rectangle verifies that the label has

been selected.

2. Click and drag the QE1 label, move it above

the energy stream icon, and release the mouse

button.

Click the left mouse button in an empty area of

the PFD window.

To place the QE1 label so that it appears on

top on the energy stream icon and, therefore,

is not mistaken to be with material stream S2.

To remove the white box around the QE1

label.

3. Object inspect reactor icon R1 and select

Move/Size Label from the drop-down menu.

To select label R1 so that you can move it. A

white rectangle verifies that the label has been

selected.

4. Click and drag the R1 label, move it below the

word C in the reactor icon, and release the

mouse button.

Note that

To place the R1 label so that it appears as

being part of the reactor icon. This label is

still selected because it is surround by a white

rectangle.

The label R1 is white and that is not your

favorite color. You will now change its color

and font style.

5. Object inspect the white rectangle of label R1,

select Changes Colours… from the drop-

down menu.

Click the red box in the Basic Colors area and

click the OK button.

To open the Color window containing basic

and custom colors in little square boxes.

To change the text color of label R1 from

black to red.

6. Object inspect the white rectangle of label R1, To open the Font window, which contains

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Tutorial 2.9

select Changes Font… from the drop-down

menu.

Click bold in the Font Styles area and click the

OK button.

Click the appropriate arrow keys (←, ↑, ↓,→)

on the keyboard.

Click the left mouse button in an empty area of

the PFD window.

areas for font type, style, and size.

To change the text of label R1 to a bold style.

To reposition the label R1, because you do not

like where it is currently positioned. You

want to get it center horizontally.

To remove the white box around the R1 label.

7. Click the Save Case icon in the HYSYS button

bar.

To save all of the changes you have made to

the PFD, so far, as a simulation case file in

one of your personal folders.

F. View some operating conditions.

In HYSYS, you can inspect the operating conditions of streams and process units

by double clicking on their icons in the PFD to open their property windows.

However, you may want to see some selected operating conditions and quickly

compare them to others but within the PFD window. Hot keys, fly-by

information, and PFD tables are the tools that allow you to observe operating

conditions.

1. Press keys <Shift><T> on the keyboard;

Press keys <Shift><P> on the keyboard;

Press keys <Shift><F> on the keyboard.

Note that

Press keys <Shift><N> on the keyboard.

To observe the Temperatures, Pressures, and

total Flow rates of all material streams in the

flowsheet.

These hot keys give you a quick overview of

the distribution of temperature, pressure, or

flow in a flowsheet. The * in front of a value

indicates that it is a specified variable, one

you supplied a number for.

To display the material stream Names again.

2. Place the cursor on stream S2 for a moment;

Place the cursor on reactor R1 for a moment.

Note that

To observe the fly-by information displayed

in a small white box for each object.

The hot keys and fly-byes provide you with

specific information about some operating

conditions. How can you get a table of

information displayed in the PFD window,

like the material stream info that appears in

the workbook?



To expand the PFD window to fit the full area

of the HYSYS desktop.

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Tutorial 2.9

Object inspect an open area of the PFD and

select Add Workbook Table from the drop-

down menu.

Click on Streams in the list, if necessary, andthen click the Select button.

Note that

To open the Select Workbook Page window.

Stream pages that appear in the Workbook

are displayed in a list.

To have a stream table placed in the PFD window.

This table is the same as what appears in the

Streams page of the Workbook. Whenever

you make changes in the content or format of

the Streams page in the Workbook, they will

automatically be reflected in this PFD table.



Click and drag the stream table so that it is

centered under the flowsheet in the PFD.



Note that

Note that

To position the entire flowsheet and the

stream table in the PFD window.

To give it a professional appearance for

documentation purposes.

To position again the entire flowsheet and the


You may sometimes what to print the PFD

window but only with the flowsheet and not

the stream table. Before you do the print, you

can hide the stream table by object inspecting

it and selecting the Hide option. You can

always retrieve hidden objects by object

inspecting the PFD and selecting the Reveal

Hidden Objects option.

You could print the PFD now, but it needs a

title, the assignment, your name, and the date.

In other words, you need to document your

work.

G. Add some documentation text.

The add text function allows you to place text such as titles and dates in the PFD.

This section will show you how to add a title to the PFD and size the title to fit

on one line. You will also add a second line for the assignment, your name, andthe date.

1. Place the cursor on the arrow at the top of the

PFD vertical scroll bar and scroll the flowsheet

and stream table down about 2 inches.

Click the Add Text icon in the PFD button bar.

To make room for some textual information

which will appear above the flowsheet.

To enter the Add Text mode. The cursor will

now appear with a white box.

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Tutorial 2.9

2. Click the cursor anywhere above the flowsheet.

Type Cumene Production from Propylene

and Benzene and click the OK button.

Do not use the <Enter> key while typing.

Note that

Click the Size Mode icon in the PFD button

bar.

Note that

Place the cursor on the right, white square of

the selected text; wait for the cursor to change

to symbol ↔, then drag the white square to the

right until the text appears as one line.

Note that

Note that

To open the Text Props View window.

To create a text box on the PFD with a title

for the flowsheet.

The text is surround by a white rectangle and

each word of the title appears to be on a new

line. However, the text box needs to be

elongated to produce a one-line title.

To enter the size mode, which allows you to

resize any object in the PFD that is selected.

The white rectangle around the text has two

small, white squares on the right and left

sides. These are the resize indicators. If the

text is not selected, just click on it to select it.

To elongate the text into a one-line title.

If you have made a spelling error in the title,

then object inspect the title and select View

Properties… from the drop-down menu, in

order to correct your error.

To give this title more prominence, you what

to increase the text font size and change itscolor.

3. Object inspect the text box and select Change

Font… from the drop-down menu.

Increase the text size to 20 and click OK.

Elongate the text to a one-line title again.

Object inspect the text box and select Change

Colour… from the drop-down menu.

Select a red color and click the OK button.

Click and drag the text box.

Note that

To open the Font window.

To increase the prominence of the title.

To open the Color window.

To change the text color of the title.

To center the title over the flowsheet. Use the

Zoom All button to help you with this task.

You are to leave enough room between the

title and the flowsheet, so that you can add

another but smaller line of text.

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Tutorial 2.9

4. Click Add Text icon in the PFD button bar;

Click the cursor anywhere below the title.

Type Tutorial 2.9, your name, date and

click the OK button.

Click and drag the right side of the text box.

Click and drag the text box.

To enter the Add Text mode and open the

Text Props View window.

To create a text box between the title and the

flowsheet containing the assignment, your

name, and the date.

To elongate it into one line of text.

To center it under the title.



Choose File/Printer Setup/Graphic

Printer… from the menu bar

Object inspect an open area of the PFD and

select Print PFD from the drop-down menu.

Note that

To position the title, the flowsheet and the


To select your printer destination for

graphical output.

To send the contents of the PFD to your

selected printer.

You have just documented and printed this

tutorial assignment. You should document all

work that you do in HYSYS. Always supply,

at least, a title, assignment number, name, and

date.

6. Click the Save Case icon in the HYSYS button

bar.

To save all of the changes you have made to

the PFD, so far, as a simulation case file in

one of your personal folders.

H. Connect and disconnect PFD objects.

Process streams and process units can be connected and disconnected, either

through object property windows or with interactive tools available on the PFD.

While using the interactive tools and also specifying additional information, you

may inadvertently cause a consistency error. HYSYS issues these kinds of

errors when a process unit simulation is over-specified; that is too much

information is known for the process unit calculation, and HYSYS can not

resolve the inconsistency. You must do that by specifying only the correct

amount of information.

In the PFD of file pfdtools.hsc, the flowsheet simulation for the heater E1 and

reactor R1 is represented mathematically as follows:

Ψ Δ Ψ

Ψ Δ Ψ

S E E S S S

S R R S S S

P Q heater T P

P Q reactor T P

2 1 1 1 2

3 1 1 2 3 3

, , , ,

, , , ,

=

=

2

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Tutorial 2.9

where heater or reactor is a function whose variables on the left are calculated by

HYSYS once those variables on the right are known. The vector Ψi is a short

notation to represent the temperature, pressure, flow rate, and chemical

composition of stream i; that is, the process state variables for that stream.

Since the process state of stream S1 and the temperature and pressure of stream

S2 are known, the heater calculation is done first by HYSYS, in order to

determine the remaining conditions of stream S2. The reactor calculation is done

second by HYSYS, because the temperature and pressure of stream S3 are known

and the conditions of stream S2 were determined by the heater simulation. This

calculation order of heater followed by reactor is called forward propagation

because it follows the material flow of the streams. Another way of looking at

the forward propagation is that the outlet streams of a process unit are

calculated once its inlet streams and equipment parameters are known.

This section shows you how to disconnect heater E1 from outlet stream S2 and

then reconnect them. You will also create and fix a consistency error associatedwith process unit E1. Proceed as follows:

1. Click the drag zoom icon in the button bar at

the top of the PFD window.

Click and drag a box that surrounds just the

flowsheet, and then release the mouse button.

To enter the zoom mode. The cursor will now

appear with a magnifying glass icon.

To choose the heater and reactor and their

attached streams. HYSYS will automatically

zoom in on the area included in the box you

have just outlined.

2. Click the Break Connection button in the

PFD button bar.

Click the blue line between heater E1 and

stream S2.

Note that

Note that

To enter the break connection mode. The

cursor will now appear with an X icon.

To break the connection of the outlet stream

on heater E1.

Stream S2 remains connected to the reactor;

however, it is light blue indicating that it is no

longer fully specified. Stream S3 is also light

blue because not enough conditions are

specified to do the reactor calculations. When

stream S2 was originally connected to heater

E1, the HYSYS simulation of heater E1 had

calculated the unknown conditions of stream

S2 and thus made them known information to

the reactor unit.

A conversion reactor in a HYSYS simulation

may produce a vapor outlet stream (S3), liquid

outlet stream (S4), or both. In this simulation,

the reaction is in the vapor phase only;

however, HYSYS requires that a liquid

product stream be defined. We will ignore

stream S4 in our discussion, since its flow rate

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Tutorial 2.9

Note that

is zero.

You will now change the propagation order in

the flowsheet by specify the process state of

stream S2. Starting with stream S2, HYSYS

will do a forward calculation on reactor R1 first, and then it will try to do a backward

calculation on heater E1. This propagation

order is represented mathematically as

follows:

Ψ Δ Ψ

Ψ Δ Ψ

S R R S S S

S E E S S S

P Q reactor T P

P Q heater T P

3 1 1 2 3

1 1 1 2 12

, , , ,

, , , ,

=

=

3

1

where reactor or heater 2 is a function whose

variables on the left are calculated by HYSYS

once those variables on the right are specified.

The vector Ψi is a short notation to represent

the temperature, pressure, flow rate, and

chemical composition of stream i.

The reactor function above depicts a forward

calculation order, while the heater 2 function

represents a backward calculation order (i.e.,

knowing an outlet stream calculate the inlet stream

conditions).

HYSYS does a process unit calculation as

soon as enough information is known, and

then it propagates the simulation both forward

and backwards until either it can not propagate further ( because not enough information is

known) or a consistency error occurs.

3. Double click the stream S2 icon in the PFD.

Double-click on the Molar Flow cell of stream

S2.

Click Mole Flows in the Composition Basis

area.

Enter 200 in CompMoleFlow cell for benzene.

Enter 150 in CompMoleFlow cell for propene.

To open the property window for stream S2.

Only the temperature and pressure of S2 are

specified, as indicated by the blue values.


window.

To select the composition basis as component

molar flow rates.

To specify the kgmoles/hour for benzene.

To specify the kgmoles/hour for proplyene.

Enter 5 in CompMoleFlow cell for propane

Enter 0 in CompMoleFlow cell for cumene.

Click the OK button in the Input Composition

for Stream window. (If it’s not visible, scroll to find

it.)

To specify the kgmoles/hour for propane.

To specify the kgmoles/hour for cumene.

To return you to the Worksheet/Conditions

page of the stream property window. The

remaining cells of stream S2 have values and

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Tutorial 2.9


Note that

its object status is green.

To close the stream property window.

In the PFD, streams S2 and S3 are dark blue

indicating that HYSYS has successfully donethe forward calculations on reactor R1.

4. Position the cursor over the green light and red

light in the HYSYS button bar.

Note that

Note that

To view the popup of “Solver Active” for the

green light and “Solver Holding” for the red

light. The background colors of these two

buttons indicate the state of the calculation

solver for HYSYS.

Currently, the background color of white for

the green light and gray for the red light

means the solver is active; that is, the green

light is on and the red light is off. Thus,

whenever you change any blue value, thecalculations are done automatically.

When the green light has a gray background

and the red light has a white background, the

solver is in the holding state; that is, the red

light is on and the green light is off. Thus,

whenever you change any blue values, the

calculations are not done at all, until you

click the green light to turn it on.

Whenever HYSYS is doing the calculations

and detects some error, it automatically stops

the calculations, turns the red light on and thegreen light off, and issues an error message.

When an error event happens, you must

diagnosis it, make the necessary corrections,

and turn the green light on to restart the

calculations.

5. Hold the Ctrl key down on the keyboard and

then proceed with the next action.

Note that

Place the cursor on the stream S2 icon. Click

and drag the blue box that appears on the left

of the stream icon to the blue box that appears

at the outlet of heater E1.

To enter temporarily the PFD attach mode

and get an arrow cursor without cross hairs.

The attach mode allows you to connect unit

operations and streams, interactively. If you

want the attach mode to be on for an extended

period of time, then click the Attach Mode icon in the button bar at the top of the PFD

window, instead of using the Ctrl key.

To attach stream S2 to heater E1. Stream S2

now becomes the outlet stream of heater E1.

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Tutorial 2.9

Note that

Note that

Note that

Note that

A Consistency Error window appears and

the calculations have been stopped, as noted

by the red STOP icon on the button bar.

Once you fix the consistency error, you will

click the green GO icon to continue the

calculations.

The Consistency Error window states that a

new value for a component mole fraction of

stream S1 was calculated by heater E1, but a

specified, blue value already existed for that

mole fraction. You must figure out what

caused this inconsistency and correct it.

The last thing you specified in the PFD was

stream S2. HYSYS always starts with the

latest change you make and propagates the

calculations from that point in the PFD. You

observed that HYSYS did the calculations onreactor R1 immediately after you specified

stream S2 because enough information was

known. HYSYS then stop its forward

propagation because a process unit was not

connected to stream S3.

When you connected stream S2 to heater E1,

HYSYS assumed you wanted a backward

propagation done on heater E1, because you

last changed stream S2. Mathematically,

HYSYS tried to do the following calculation:

Ψ Δ ΨS E E S S S

P Q heater T P1 1 1 2 12, , , ,=

1

After HYSYS completed this backward

calculation for the conditions of stream S1, it

observed that some conditions of this stream

had previously been specified with blue

values. This detection by HYSYS caused the

consistency error.

Note that

Note that

Before you disconnected stream S2, HYSYS

did a forward calculation on heater E1,

because the process state of stream S1 was

specified. After you disconnected streamS2

,specified its process state, and reconnected it,

HYSYS tried to do a backward calculation on

heater E1. The resulting consistency error

indicates that the simulation on heater E1 is

over-specified. Too much information is

known.

At this point, you have two choices to correct

the consistency error. You can de-specify the

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Tutorial 2.9

total and component flow rates of either

stream S2 or S1. You decision is based on

whether you want to do a backward or

forward calculation on heater E1. For this

tutorial, you want to do a backward

calculation; that is, calculate the total flowrate and composition of stream S1.

6. Click the Close button in the Consistency

Error window.

Proceed to Step 7.

Note that

To close the Consistency Error window so

you can fix the error.

If you used the Ctrl key to attach stream S2 to

heater E1.

However, if you used the Attach Mode icon in

the button bar at the top of the PFD window

to make the connection, then click the Attach

Mode icon to exit the PFD attach mode and

then get an arrow cursor with cross hairs

You must exit the attach mode before you can

change any process variables in the PFD.

7. Double click on heater E1 icon in the PFD.

Note that

Click the Worksheet/Conditions page, if

necessary.

Click in the Molar Flow cell of stream S1 and

then hit the <Delete> key.

Double-click on the Molar Flow cell of stream

S1.

Click the Erase button in the Composition

Controls area and then click the OK button.


Note that

To open the property window of heater E1.

The object status of heater E1 is a yellow

“Unknown Duty”, which implies that the

calculation for this stream could not be done

because of the consistency error.

To view the conditions of stream S1.

To delete the specified molar flow rate of

stream S1 and replace it with a blue <empty>.


window.

To erase the specified mole fractions of

stream S1 and replace them with four blue

<empty>’s.

To close the property window of heater E1

and return to the PFD window.

In the PFD, stream S2 is fully specified

because its material stream is dark blue.

Stream S1 is only partially known because its

material stream is light blue. Since the

temperature and pressure of stream S1 are

known, HYSYS should have done a backward

calculation on heater E1. However, HYSYS

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Tutorial 2.9

is currently in the hold state, as implied by

the red STOP icon on the button bar.

8. Click the Solver Active icon on the button bar;

that is, the green GO icon.

To continue the simulation calculations on

heater E1 based on a backward propagation.

Note that

Note that

You have resolved the consistency error, and

HYSYS has successfully done the simulation

calculations, because all material streams are

dark blue and all energy streams are dark

maroon in the flowsheet of the PFD.

HYSYS always activates the red STOP icon

on the button bar whenever a consistency

error occurs. After you have fixed a

consistency error, you must remember to

click the green GO icon, in order to have

HYSYS continue the simulation calculations.

I. Copy a PFD to a Word document.

After you complete your work on a HYSYS assignment, you may want to paste

either part of the PFD or the whole PFD into a page of a Word document that you

are preparing for your formal solution to an assignment. Proceed as follows to

capture the current PFD, paste it as a picture into a Word document, and then

manipulate this picture to see only the flowsheet figure:

1. Click the PFD icon on the button bar, if

necessary.



Click the cursor in an empty area, then

Move the mouse out of the PFD window.

Press the Print Screen (or PrtScrn) key in the

upper-right portion of the keyboard.

Note that

To bring the PFD to the top of the desktop, in

order to prepare it for capture to the clipboard.


window.

To de-activate any thing that is selected, and

to remove the cross hairs from the PFD.

To capture the complete contents of the

monitor screen as a picture image in the

computer's clipboard.

These above tasks complete what you have to

do in the HYSYS program. You will nowcopy the captured picture image and

manipulate it using the Microsoft Word

program.

2. Choose Start/Word 2003 from the Windows

desktop.

Close the Getting Started box on the far right,

To start the Microsoft Word program, which

will open with a new document.

To display fully the word document window.

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Tutorial 2.9

if it is visible.

Click the Show/Hide ¶ icon on the button bar. To show the paragraph marks.

Press the Enter key on the keyboard twice.

Place the cursor in the second line.

Select Edit/Paste from the Word menu bar.

Object inspect the pasted picture and then

select Show Picture Toolbar from the drop-

down menu.

Select the Crop button in the Picture Toolbar.

Place the Crop cursor over the little blacksquare in the middle of the left edge of the

picture. Click and drag this edge to the left

edge of the flowsheet.

Place the Crop cursor over the little black

square in the middle of the right edge of the

picture. Click and drag this edge to the right



square in the middle of the top edge of the

picture. Click and drag this edge to the top



square in the middle of the bottom edge of the

picture. Click and drag this edge to the bottom


Click the Set Transparent Color button in the

Picture Toolbar bar and then click its cursor

in the lower left area of the cropped picture.

Close the Picture Toolbar.

To add two more lines to the new document.

To identify the insertion point for the picture.

To insert the picture from the clipboard into

the Word document.

To get the popup Picture Toolbar of buttons.

To get a cursor that looks like the Crop

button icon.

To remove the left portion of the picture up tothe left edge of the flowsheet.

To remove the right portion of the picture up

to the right edge of the flowsheet.

To remove the top portion of the picture up to

the top edge of the flowsheet.

To remove the bottom portion of the picture

up to the bottom edge of the flowsheet.

To turn the background color in the picture to

white.

To remove it from the document window.

.

3. Click the cursor inside of the cropped picture,and click the Center icon on Word button bar.

Object inspect the flowsheet picture and then

select Borders and Shading… from the drop-

down menu.

Select Box and 1½-pt width, and click the OK

button.

To select the flowsheet picture and center itwithin the line of the Word document.

To get the Borders window.

To place a border around the flowsheet

picture.

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Tutorial 2.9

Object inspect the flowsheet picture again and

select Format Picture… from the drop-down

menu.

Select the Size tab, change the Scale Height and Width to 100%, and click the OK button.

Click the cursor somewhere outside the picture.

Note that

To get the Format Picture window.

To enlarge the flowsheet picture.

To deactivated the flowsheet picture.

You can now place a centered figure title on

the next line right under the flowsheet picture.

4. Choose File/Exit from the menu bar,


To exit the Microsoft Word program and not

save the Word document.

J. Close the simulation case.


Proceed as follows:



or




not save it.

2. Choose File/Exit from the menu baror


To exit the HYSYS program, if you do not plan to do another process simulation case.

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Overview

This chapter provides five problem assignments to help you develop your abilities andconfidence to simulate individual process units using the HYSYS process simulation software.Over a five-week period, you will have weekly assignments that focus on finding the material andenergy balance requirements for the following individual process units:

Problem Description

HY.1 Process Stream SimulationHY.2 Pump Simulation

HY.3 Cooler SimulationHY.4 Mixer/Tee SimulationHY.5 Reactor Simulation

Each weekly problem will be assigned in a separate memorandum. Once you’ve completed

these assignments, you will have a mathematical understanding of how HYSYS does itscalculations for each process unit.

This chapter assumes you have completed certain tutorials found in Chapter 2.They are Tutorials 2.1 to 2.6 and 2.9. Each assignment in this chapter identifies those

tutorials that you should complete before you try to solve the problem.

While solving a problem, you will need to consult Appendices B, C, etc. in this

handbook for information on certain HYSYS simulation modules. Each appendix or module provides a mathematical explanation of how HYSYS does its calculations for that process unit. Amodule includes a description, a conceptual model, a mathematical model, variable descriptions,example mathematical algorithms, and several HYSYS simulation algorithms. Each assignmentidentifies which appendix you must consult.

Microsoft Word files of the five assignments in this chapter are available on thedepartments network file server (R:) in folder chem_engineering/public/HYSYS

Manual/Chap 3. Your instructor will give you directions on how to access this folder.

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Problem HY.1

Process Stream Simulation

The HYSYS simulation module for a process stream is fully defined in Appendix C ofthis handbook. This process stream module contains a process description, process diagram,

assumptions, mathematical model, variable descriptions, mathematical algorithms, and someHYSYS simulation algorithms in functional form. After you read this information about a process stream, you are to practice the HYSYS session below and then do the simulationexercise. For your solution of Problem HY.1, you are to provide a printed copy of the HYSYS

flowsheet and the worksheet datasheet for the process stream in the simulation exercise only.Furthermore, you are to provide answers to the questions in the simulation exercise.

HYSYS Session

This session will show you, in general terms, how to do a HYSYS simulation for a process stream. It assumes you are familiar with the material in Tutorials 2.1 to 2.5 of this

handbook. You are to find the vapor fraction and heat flow in BTU/hr of a binary mixture oftoluene and hexane at 1 atm and 100°C. This mixture is flowing at 100 kgmol/h. The stream is

labeled feed and its conceptual diagram is:

T

P

n

z

z

F

F

F

F TL

F HX

= °

=

=

=

=

100 C

1 atm

100 kgmol / h

0.7

0.3

&

,

,

feed

T

P

n

z

z

F

F

F

F TL

F HX

= °

=

=

=

=

100 C

1 atm

100 kgmol / h

0.7

0.3

&

,

,

Using the information from above, you are to practice a HYSYS simulation by doing thefollowing general tasks:

• Create a new HYSYS file. Name it xxx_HY1, where xxx are your initials.

• Choose a property package. Select the SRK property package, which is anequation of state.

• Specify the two chemical components.

• Create a process stream and name it feed.

• Specify the state of this process stream; that is, its temperature, pressure,flow rate, and composition.

• Change the HYSYS preferences to display your desired property units.

• Observe the HYSYS calculated results, which appear in black. Note that

values you supplied appear in blue.

After you specify the state of the process stream, HYSYS immediately calculates all of the other properties of that streams (such as mass flow rate, volumetric flow rate, vapor fraction, etc.) using the Soave-Redlich-Kwong (SRK) equation of state. The answers for two of the stream properties are:

Vapor Fraction = 0.783Heat Flow = -1.230E6 BTU/h

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Problem HY.1

A value for the vapor fraction between zero and one indicates that the process stream exists as atwo-phase system (vapor and liquid) at the specified temperature, pressure, and composition.

Simulation ExerciseWhat are the temperature in °F and the heat flow in BTU/hr of a process stream

containing a tertiary mixture of benzene, hexane, and toluene? The stream is at 2 atm and has avapor fraction equal to zero. The chemical component flows are as shown below.

V

T

P

n

n

n

n

f

F

F

F

F BZ

F HX

F TL

=

=

=

=

=

=

=

0.0

?

2 atm

?

40 kgmol / h

70 kgmol / h

120 kgmol / h

&

&

&

&

,

,

,

feed

V

T

P

n

n

n

n

f

F

F

F

F BZ

F HX

F TL

=

=

=

=

=

=

=

0.0

?

2 atm

?

40 kgmol / h

70 kgmol / h

120 kgmol / h

&

&

&

&

,

,

,

While you are completing your HYSYS simulation on the above process stream problem, pleaseanswer the following questions:

1. Which HYSYS simulation algorithm in Appendix C of the Process StreamModule would you use to solve the above problem? What temperature does thisalgorithm calculate?

2. Which assumption(s) support the fact that a process stream has uniform

properties throughout its length?

3. What steps from the Mathematical Algorithm A would you use to calculate themass fractions from the mole fractions? Verify that HYSYS has done thiscalculation correctly?

4. Calculate the enthalpy of the stream in BTU/lb using the appropriatemathematical model equation(s).

5. What are the definitions of the dew-point tem perature and bubble-pointtemperature?

6. How might you find the dew-point temperature of this stream? What is thisvalue?

For the above process stream problem, please print its HYSYS flowsheet and its worksheetdatasheet.

Beef, Inc. 3-3 7/29/01




Problem HY.2

Pump Simulation

The HYSYS simulation module for a pump operation is fully defined in Appendix E ofthis handbook. This pump module contains a process description, process diagram, assumptions,

mathematical model, variable descriptions, mathematical algorithms, and some HYSYSsimulation algorithms in functional form. After you read this information about a pumpoperation, you are to practice the HYSYS session below and then do the simulation exercise. Foryour solution of Problem HY.2, you are to provide a printed copy of the HYSYS flowsheet and

the design and worksheet datasheets for the pump operation in the simulation exercise only.Furthermore, you are to provide answers to the questions in the simulation exercise.

HYSYS Session

This session will show you how to do a HYSYS simulation for the pump operation. Itassumes you are familiar with the material in Tutorials 2.1 to 2.5 of this handbook. You are tofind the power in watts to compress an equimolar mixture of n-hexane and n-octane at 25°C from

1 atm to 4 atm. This liquid mixture is flowing at 100 lb-moles per hour. The pump is labeled P-200, and its adiabatic efficiency is 70 percent. The conceptual diagram is:

T

P

n

z

z

I

I

I

I HX

I OC

= °

=

=

=

=

25

1

100

0 5

0 5

C

atm

lbmol/ h

.

.

,

,

T

P

n

z

z

E

E

E

E HX

E OC

=

=

=

=

=

?

?

?

?

,

,

4 atm

ε = 70%

Inlet

Exit

P-200

?W A

=

Using the information from above, you are to practice a HYSYS simulation by doing the

following general tasks:

•

Create a new HYSYS file. Name it xxx_HY2, where xxx are your initials.

• Choose a property package. Select the SRK property package, which is anequation of state.


• Create a pump and name it P-200.

• Create the pump inlet, outlet, and energy streams. Name them Inlet, Exit,

and Wa, respectively.

• Supply the adiabatic efficiency of 70%.

• Specify the state of the inlet stream; that is, its temperature, pressure, flow

rate, and composition.• Specify the exit pressure.


• Observe the HYSYS calculated results, which appear in black. Note thatvalues you supplied appear in blue.

After you specify the state of the inlet stream, the exit pressure, and the pump efficiency, HYSYSimmediately calculates all of the other properties of the two streams (such as mass flow rate, volumetric

flow rate, vapor fraction, heat flow, etc.) using the Soave-Redlich-Kwong (SRK) equation of state.Also, HYSYS calculates the pump power to be:

Beef, Inc. 3-4 7/29/01




Problem HY.2

Power = 0.81 watts

A positive value for the pump power indicates that energy must be added to the process stream toincrease its pressure.

Simulation Exercise

What adiabatic efficiency and power in kilowatts are required to compress an equimolarmixture of n-hexane and n-octane from 25°C and 1 atm to 40°C and 400 atm? This liquidmixture is flowing at 100 lb-moles per hour.

T

P

n

z

z

I

I

I

I HX

I OC

= °

=

=

=

=

25

1

100

0 5

0 5

C

atm

lbmol/ h

.

.

,

,

T

P

n

z

z

E

E

E

E HX

E OC

= °

=

=

=

=

40

400

C

atm

?

?

?

,

,

ε = ?

Inlet

Exit

pump

?W A

=

While you are completing your HYSYS simulation on the above pump problem, please answerthe following questions:

1. Which HYSYS pump simulation algorithm ( pumpa, pumpb, etc. in Appendix E) would youuse to solve this problem? What are the given variables and their values? What arethe calculated variables and their values?

2. After you examine the process states (i.e., the temperature, pressure, flow rate, and

composition) of the inlet and exit streams, please answer the following questions. Whydoes the exit temperature increase slightly? What is unique about the molar flow rateand composition? What equations in the math model and steps in the algorithmreflect it? What assumptions support this uniqueness? What are the operatingconditions that would invalidate each assumption?

3. What is the ideal work expressed in units of horsepower?

4. In the math algorithm, what variables are only functions of the material state (i.e., the

temperature, pressure, and composition) of the liquid?

5. What does the assumption of “adiabatic process” imply? Is this a valid assumption?

6.

What is the energy relative imbalance (%RIB) ? Show your calculations. The energy%RIB equals 100*(energy flow in - energy flow out) / (energy flow in).

For the above pump problem, please print its HYSYS flowsheet and its design and worksheetdatasheets.

Beef, Inc. 3-5 7/29/01




Problem HY.3

Cooler Simulation

The HYSYS simulation module for a cooler operation is fully defined in Appendix G ofthis handbook. This cooler module contains a process description, process diagram, assumptions,

mathematical model, variable descriptions, mathematical algorithms, and HYSYS simulationalgorithms in functional form. After you read this information about a cooler operation, you areto practice the HYSYS session below and then do the simulation exercise. For your solution ofProblem HY.3, you are to provide a printed copy of the HYSYS flowsheet and the design andworksheet datasheets for the cooler operation, as well as the plot generated by the case study, in

the simulation exercise only. Furthermore, you are to provide answers to the questions in thesimulation exercise.

HYSYS Session

This session will show you how to do a HYSYS simulation for a cooler and perform a

case study on the operation. It assumes you are familiar with the material in Tutorials 2.1 to 2.5of this handbook. You are to find the duty in BTU/h needed to cool a mixture of ethanol andwater from 200°C and 583 kPa to a saturated vapor at 570 kPa. This stream is flowing at 900 kg-moles per hour. The cooler is labeled E-200, and its pressure drop is 13 kPa. The conceptualdiagram is:

E-200

?Q = V

T

P

n

z

z

f

E

E

E

E ET

E WA

=

=

=

=

=

=

1.0

?

kPa

?

570

?

?

,

,

T

P

n

z

z

I

I

I

I ET

I WA

= °

=

=

=

=

200

583

900

0 6

0

C

kPa

kgmol / h

.

.4

,

,

Inlet Exit

Using the information from above, you are to practice a HYSYS simulation and case study bydoing the following general tasks:

•

Create a new HYSYS file. Name it xxx_HY3, where xxx are your initials.

• Choose a property package. Select the PRSV property package, which is anequation of state.


• Create a cooler and name it E-200.

• Create the cooler inlet, outlet, and energy streams. Name them Inlet, Exit,

and Q, respectively.

•

Specify the state of the inlet stream; that is, its temperature, pressure, flowrate, and composition.

• Specify the exit pressure and vapor fraction.



Beef, Inc. 3-6 7/29/01




Problem HY.3

After you specify the state of the inlet stream and the exit pressure and vapor fraction, HYSYSimmediately calculates all of the other properties of the two streams (such as mass flow rate, volumetric

flow rate, vapor fraction, heat flow, etc.) using the PRSV equation of state. Also, HYSYS calculates thecooler heat duty to be:

Q = 3.8309x10^6 BTU/hr

Based on thermodynamic sign conventions, this should have a negative value to indicate that

energy is removed from the process stream. However, a positive duty for a cooler operation inHYSYS indicates energy is being removed from the stream.

Q

The case study tool allows you to monitor the steady state response of key process variables tochanges in your process. Basically, the case study allows you to do “what if” analyses. In thissession, you are observing how the duty of the cooler varies when the exit temperature is changedfrom 200°C to 10°C. The following general tasks must be completed to perform the case study.Detailed instructions for each of these tasks is given in Tutorial 2.4 of this handbook.

• Insert the variables into the DataBook for your case study. These two variables are theheat duty of cooler E-200 and the temperature of the exit stream.

•

Begin your “what if” analysis.

• Activate the IND check box for temperature and the Dep check box for the heat duty.

• Supply a Low Bound, High Bound, and Step Size for the temperature; that is, 10°C,

200°C, and 5°C, respectively.

• Begin the calculations and generate the plot of heat duty versus temperature.

Simulation Exercise

What heat duty in kJ/h is removed from an equimolar mixture of n-hexane and n-octaneto cool it from 300°C at 2 bar to a saturated vapor? a saturated liquid? a subcooled liquid at100°C? What are the final temperatures of the exit stream in the first two cases? This liquidmixture is flowing at 100 lb-moles per hour. The cooler has a 0.2 bar pressure drop.

Perform a case study to observe the effect of cooler duty as the independent variableversus the exit temperature as the dependent variable. Be sure to define a range of exittemperatures that includes both the single-phase regions (vapor and liquid) and the two-phase region(vapor-liquid).

Cooler

V

T

P

n

z

z

f

E

E

E

E HX

E OC

=

=

=

=

=

=

?

?

?

?

,

,

T

P

n

z

z

I

I

I

I HX

I OC

= °

=

=

=

=

300

2100

0 5

0 5

C

bar lbmol / h

.

.

,

,

?Q =

Inlet Exit

ΔP = 0 2. bar

Beef, Inc. 3-7 7/29/01




Problem HY.3

While you are completing your HYSYS simulation on the above cooler problem, please answerthe following questions:

1. Which HYSYS heater/cooler simulation algorithm in Appendix G would you use tosolve the exit phase problems? to solve the exit temperature problem? WhichHYSYS heater/cooler simulation algorithm would you use to solve the case study problem?

2. Compare the cooler operation to the pump operation. Which assumptions for the twooperations are the same? How do they differ? Why are some assumptions different?

3.

The total energy of a process stream is composed of its molar enthalpy, kineticenergy, and potential energy. For the subcooled exit stream, what percentage of itstotal energy is potential energy? kinetic energy? (hint, a trick question)

4.

Which equations in the mathematical model would you use to calculate the molarenthalpy of the exit stream given the conditions of the inlet stream and the duty of thecooler? Use these equations to find the exit stream molar enthalpy for a coolingoperation with the inlet stream in this problem, and a duty of 2000 watts. Check thatHYSYS calculates the same result.

5. In your printed case-study plot, label the dew-point temperature and bubble-pointtemperature on the temperature axis. After doing this task, you should notice threedistinct areas on the plotted curve. Place a label on the liquid portion, vapor-liquid portion, and vapor portion of this plot.

This temperature-heat-duty plot is for a multicomponent mixture. What would thevapor-liquid portion of this plot look like, if the mixture contained only one chemicalcomponent (e.g., pure n-hexane)?

6.

What is the energy relative imbalance (%RIB) for an exit temperature of 100°C?Show your calculations. The energy %RIB equals 100*(energy flow in - energyflow out) / (energy flow in).

For the above cooler problem at an exit temperature of 100°C, please print its HYSYS flowsheet,its design and worksheet datasheets, and the plot generated by the case study.

Beef, Inc. 3-8 7/29/01




Problem HY.4

Mixer/Tee Simulation

The HYSYS process simulator can solve the material and energy balances of many unitoperations that are interconnected by process streams. For example, two or more process streams

can be fed to the HYSYS mixer operation to form one exit stream. This exit stream can then befed to a HYSYS tee operation to split it into several streams. Problem HY.4 uses this example toillustrate how to do a process simulation that has several unit operations in a process flowdiagram (PFD).

The HYSYS simulation module for a stream mixer operation is fully defined in AppendixD of this handbook. The stream mixer module contains a process description, process diagram,assumptions, mathematical model, variable descriptions, mathematical algorithm, and HYSYS

simulation algorithms in functional form. No simulation module exists for the tee operation inthis handbook. After you read the information about the stream mixer, you are to practice theHYSYS session below and then do the simulation exercise. For your solution of Problem HY.4,you are to provide a printed copy of the HYSYS flowsheet and the design and worksheet

datasheets for the mixer and tee operations in the simulation exercise only. Furthermore, you areto provide answers to the questions in the simulation exercise.

HYSYS Session

This session will show you how to do a HYSYS simulation for a stream mixer and a tee,and how to attach two process units. It assumes you are familiar with the material in Tutorials2.4, 2.5, and 2.9 of this handbook. First, a pure heptane stream is mixed with a pure octanestream. The resulting binary mixture is then split into two streams with different flow rates. Youare to find the molar flow rate in kgmol/h and the mole fractions of the tee’s two exit streams.The pure heptane stream is flowing at 100 kg-moles per hour, and the pure octane stream is

flowing at 200 kg-moles per hour. Both pure streams are at ambient conditions (25°C and 1 atm).The tee exit streams are also at ambient conditions, which assumes no pressure drop across themixer or the tee. One tee exit stream is to contain 40% of molar flow rate of the tee inlet stream.The conceptual diagram is:

T

P

n

z

z

T

P

n

z

z

E

E

E

E HP

E OC

E

E

E

E HP

E OC

1

1

1

1

1

2

2

2

2

2

=

=

=

=

=

=

=

=

=

=

?

?

?

??

?

?

?

?

?

,

,

,

,

T

P

n

z

T

P

n

z

H

H

H

H HP

O

O

O

O OC

= °

=

=

=

= °

=

=

=

25

1

100

1 0

251

200

1 0

C

atm

kgmol / h

Catm

kgmol / h

.

.

,

,

Octane

Exit1

Exit2

M-200 T-200

Heptane

Mix

.4 n n E M 1 0=


Beef, Inc. 3-9 7/29/01




Problem HY.4



•

Specify the two chemical components.• Create a mixer and name it M-200.

•

Create two mixer inlet streams and one mixer outlet stream. Name them

Heptane, Octane, and Mix, respectively.

•

Specify the state of the inlet streams using the Worksheet/Conditions page;that is, supply the temperature, pressure, flow rate, and composition of theheptane stream and the octane stream.

• Specify the pressure of the mixer outlet stream using the Design/Parameters

page. To do this, select Set Outlet to Lowest Inlet. In this problem, themixer outlet will have the same pressure as the inlet streams.

• Create a tee and name it T-200.

• Attach the mixer outlet stream as the inlet to the tee and create the tee exit

streams. Name the exit streams Exit1 and Exit2.• Specify the flow ratios using the Splits page. If the tee has N exit streams,

then you must specify the flow ratios for N-1 of them. An exit stream’s flowratio indicates what fraction of the tee’s inlet stream is to appear in that exitstream. A flow ratio has a value between zero and one, and all flow ratiossum to one.

Enter 0.4 for the Exit1 flow ratio. HYSYS calculates an Exit2 ratio of 0.6.



After you specify the given process variables, HYSYS immediately calculates all of the other

properties of the streams using the PRSV equation of state. HYSYS calculates the Exit1 and

Exit2 flow rates and compositions to be:

Property Exit1 Exit2

Molar flow rate 120 kgmol/h 180 kgmol/h

Mole fraction heptane 0.3333 0.3333

Mole fraction octane 0.6667 0.6667

Simulation Exercise

What are the exit stream molar flow rates (lbmol/hr) and mass compositions in thefollowing process? A binary mixture of methanol and ethanol at 45°C and 300 kPa is mixed witha pure water stream at ambient conditions. The methanol and ethanol component flow rates are50 kgmol/h and 75 kgmol/h, respectively. The water flow rate is 100 kgmol/h. The resulting 3-component stream is then split into two exit streams. The total molar flow rates for these two exitstreams are in a 3:1 ratio, as shown in the diagram below. For the mixer, the outlet pressure isequal to the lowest inlet pressure.

Beef, Inc. 3-10 7/29/01




Problem HY.4

T

P

n

z

z

z

T

P

n

z

z

z

E

E

E

E ME

E ET

E WA

E

E

E

E ME

E ET

E WA

1

1

1

1

1

1

2

2

2

2

2

2

=

=

=

=

=

=

=

=

=

=

=

=

?

?

?

?

?

?

?

?

?

?

?

?

,

,

,

,

,

,

T

P

n

n

T

P

n

z

A

A

A ME

A ET

W

W

W

W WA

= °

=

=

=

= °

=

=

=

45

300

50

75

25

1

100

1 0

C

kPa

kgmol / h

kgmol / h

C

atm

kgmol / h

.

,

,

,

Water

Exit1

Exit2

M-200 T-200

Alcohol

Mix

n

n

E

E

1

2

3

1=

While you are completing your HYSYS simulation on the above problem, please answer thefollowing questions:

1. Which HYSYS stream mixer simulation algorithm in Appendix D would you use tosolve the mixer section of this problem? What other unit parameter, which is notreferred to in the algorithm, must you specify in HYSYS?

2. What are the temperature in °F, mass density in kg/m3, molar enthalpy inkcal/kgmole, and molar volume in m3/kgmole of the tee’s inlet and outlet streams?What is unique about these values? What are the temperature, mass density, molarenthalpy, and molar volume, in the same units, of the mixer’s inlet and outletstreams? How do these values for the mixer streams differ from those for the tee?

Why?

3. No simulation module exists for the tee operation in the blue HYSYS manual. Writethe mathematical model for a tee. ( Note that the tee operation is analogous to taking a liquid

mixture in a large beaker and pouring it into two smaller beakers. What is true about the state of the

material in all three beakers?)

4. What is the material relative imbalance (%RIB) for the process flowsheet? Showyour calculations. The material %RIB equals 100*(mat’l flow in - mat’l flow out) /(mat’l flow in).

You are to draw an overall system boundary around the flowsheet, which contains

the mixer and tee operations. The only material and energy streams you are toconsider in your imbalance calculation are those that cut your overall system

boundary. Therefore, you would not consider stream Mix in your calculations.

5.

What is the energy relative imbalance (%RIB) for the process flowsheet? Show yourcalculations. The energy %RIB equals 100*(energy flow in - energy flow out) /(energy flow in).

Beef, Inc. 3-11 7/29/01




Problem HY.4

For the above problem, please print its HYSYS flowsheet and the design and worksheetdatasheets for the mixer and tee.

Beef, Inc. 3-12 7/29/01




Problem HY.5

Reactor Simulation

The HYSYS simulation module for a chemical reactor operation is fully defined inAppendix D of this handbook. The chemical reactor module contains a process description,

process diagram, assumptions, mathematical model, variable descriptions, mathematicalalgorithm, and HYSYS simulation algorithms in functional form. After you read this informationabout the reactor, you are to practice the HYSYS session below and then do the simulationexercise. For your solution of Problem HY.5, you are to provide a printed copy of the HYSYSflowsheet and the design, reactions, and worksheet datasheets for the chemical reactor in the

simulation exercise only. Furthermore, you are to provide answers to the questions in thesimulation exercise.

HYSYS Session

This session will show you how to do a HYSYS simulation for a chemical reactor. It

assumes you are familiar with the material in Tutorials 2.5 and 2.6 of this handbook. Acrylonitrile is produced by the reaction of propylene, ammonia, and oxygen:

2 C3H6 + 2NH3 + 3O2 → 2 C3H3 N + 6 H2O

where 30 molar percent of the propylene is converted.

A 45 mole % propylene and 55 mole % ammonia stream at 25 °C and 1 atm is fed to thereactor. The oxygen is fed to the reactor through an air stream also at 25°C and 1 atm. The feedstream is flowing at 22 kgmol/h, and the air stream is flowing at 78 kgmol/h. Assume anadiabatic reactor with no pressure drop. You are to find the temperature of the reactor productstream in °C. Also, you are to find the dew-point temperature (Vf = 1) of the reactor product

stream. The conceptual diagram is:

T

P

n

z

z

z

z

z z

P

P

P

P PY

P AM

P O

P N

P AN

P WA

=

=

=

=

=

=

=

=

=

?

1 atm

?

?

?

?

?

??

,

,

,

,

,

,

2

2

Product

Feed

Air

R-200R-200

T

P

n

z

z

T

P

n

z

z

F

F

F

F PY

F AM

A

A

A

A O

A N

= °

=

=

=

=

= °

=

=

=

=

25

1

22

0

0 55

25

1

78

0 21

0 79

2

2

C

atm

kgmol/ h

C

atm

kgmol/ h

.45

.

.

.

,

,

,

,

ε = 30% of PY



Beef, Inc. 3-13 7/29/01




Problem HY.5


• Specify the six chemical components.

• Go to the Reactions tab of the Simulation Basis Manager and add the

reaction components.• Add the conversion reaction. Specify the stoichiometry and basis. Be sure to

enter a propylene conversion of 30%, not 0.30%.

• Define the Global Rxn Set to include this conversion reaction.

•

Connect the Global Rxn Set to the current Fluid Package.

• Enter the simulation environment and create a conversion reactor named R-

200.

• Create two inlet streams, Feed and Air, and one reactor outlet vapor stream,

Product, and one outlet liquid stream, noLiquid. The only product in thiscase is a vapor. This is an adiabatic reactor, so no energy stream is required.Do not supply an energy stream name.

•

Specify the process state of each of the two reactor feed streams.

•

Set the reactor pressure drop to zero and select the Global Rxn Set.• Observe the HYSYS calculated results, which appear in black. Note that

values you supplied appear in blue.

After you specify the feed and air streams and the chemical reaction, HYSYS immediatelycalculates the product stream state using the PRSV equation of state. For the product stream, itstemperature is:

T = 425.25°C

The process state of the reactor product stream is calculated by HYSYS. The streamvariables cannot be changed by the user, because their values appear in black. To find the dew-

point temperature of the product stream, you must create a new stream with the same flow rate,composition and pressure of the product stream. First, place a new stream on the PFD and name

it junk. Second, double click on this new stream to open its property window. Select the Util

tab, press the Copy Stream Specs From... button, and select the Product stream. Select the Cond tab and set the vapor fraction (Vf = 1) to find the dew point. HYSYS calculates a dew-pointtemperature of:

T = 43.73°C

Simulation Exercise

For the simulation exercise, consider the same reaction and reactor feed streams that were used inthe HYSYS session. Now the reactor is no longer adiabatic. Instead, it is an isothermal process,meaning the product stream is at the same temperature as the feed streams, 25°C. What is thereactor duty in kJ/h for this isothermal process?

Beef, Inc. 3-14 7/29/01




Problem HY.5

?Q = T

P

n

z

z

z

z

z

z

P

P

P

P PY

P AM

P O

P N

P AN

P WA

= °

=

=

=

=

=

=

=

=

25 C

1 atm

?

?

?

?

?

?

?

,

,

,

,

,

,

2

2

ProductFeed

Air

R-200R-200

T

P

n

z

z

T

P

n

z

z

F

F

F

F PY

F AM

A

A

A

A O

A N

= °

=

=

=

=

= °

=

=

=

=

25

1

22

0

0 55

25

1

78

0 21

0 79

2

2

C

atm

kgmol/ h

C

atm

kgmol/ h

.45

.

.

.

,

,

,

,

ε = 30% of PY

While you are completing your HYSYS simulation on the above problem, please answer thefollowing questions:

1.

For the adiabatic reactor simulation in the HYSYS session, only a vapor productstream was required. For the isothermal case, both a vapor and a liquid productstream is required, as indicated by the red status bar. Why? Above what reactor exittemperature will only a vapor product stream be required?

2.

What is the acrylonitrile composition in the liquid product stream in mole fraction?in mass fraction? in parts per million (ppm)? in kg/m3? in kgmol/m3? in molarity

(M)? Use the Workbook/Setup... option to add the actual volume flow to theworkbook.

3. What assumptions were used to solve this reactor simulation problem? Comparethese assumptions to those of the chemical reactor module in Appendix H of thishandbook. Are the assumptions the same? If not, how do they differ?

4. Write the overall mole balance equation containing R for the acrylonitrile reaction problem. What are the reaction constant and its units for acrylonitirle production?

5. What is the energy relative imbalance (%RIB)? Show your calculations. The energy%RIB equals 100*(energy flow in - energy flow out) / (energy flow in).

6. What is the material relative imbalance (%RIB) on a total molar basis? Show yourcalculations. The total molar %RIB equals 100*(total material flow in - totalmaterial flow out) / (total material flow in).

7.

What is the material relative imbalance (%RIB) on a total mass basis? Show yourcalculations. How does this compare with the %RIB on a molar basis? Explain.

For the above problem, please print its HYSYS flowsheet and the reactor design, reactions, andworksheet datasheets.

Beef, Inc. 3-15 7/29/01




Overview

This chapter provides seven problem assignments to help you develop a processflowsheet to make styrene monomer from toluene and methanol by analyzing individual processunits and then connecting these individual units to form the complete flowsheet. Over a seven-week period, you will have weekly assignments that focus on particular sections of the flowsheet, beginning with the reaction section. In these assignments, you will conduct a process simulationon each of the following flowsheet sections using the HYSYS process simulation software:

Problem Description

SM.1 Styrene Monomer Reaction SectionSM.2 Reactor Effluent Cooling/Decanting SectionSM.3 Methanol Recycle Purification SectionSM.4 Toluene Recycle Purification SectionSM.5 Toluene/Methanol Feed Preparation Section

SM.6 Recycle Mixing and Preheating SectionSM.7 Styrene Monomer Purification Section

Each weekly problem will be assigned in a separate memorandum. Once you’ve completed

these assignments, you will have synthesized the process flowsheet and determined its processingrequirements for material and energy.

This chapter assumes you have completed certain tutorials found in Chapter 2.They are Tutorials 2.1 to 2.6 and 2.9. Also, the problem assignments in Chapter 3 on process units should be completed before you begin your analysis of the processflowsheet to produce styrene monomer from toluene and methanol.

Technical materials needed to solve the problems in this chapter are provided inAppendices A, B, C, etc. of this handbook. Appendix A provides complete technical data for the

production of styrene monomer from toluene and methanol. Appendices B, C, etc. containsimulation modules for various process unit operations. Each appendix or module provides amathematical explanation of how HYSYS does its calculations for that process unit. A moduleincludes a description, a conceptual model, a mathematical model, variable descriptions, examplemathematical algorithms, and several HYSYS simulation algorithms. Please consult theappropriate appendices to complete an assigned problem.

Microsoft Word files of the seven assignments in this chapter are available on the

departments network file server (R:) in folder chem_engineering/public/HYSYS

Manual/Chap 4. Your instructor will give you directions on how to access this folder.

Beginning with the second problem, you will be provided with the HYSYS solution forthe previous problem. You are to begin the next problem by starting with the solution to the

previous problem. You can find this previous HYSYS solution in the Blackboard CHEG 200

course under the Assignments section.

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Problem SM.1

Styrene Monomer Reaction Section

The heart of a process flowsheet is the reactor. The first step in designing a chemical process flowsheet is to define the reactor operating conditions. These conditions are used to

simulate the performance of the reactor. Once the reactor has been simulated, other parts of theflowsheet can be developed.

From the reactor performance table found in Appendix A, you are to use one of the inlettemperatures to the adiabatic reactor, in order to complete a reactor simulation that forms styrenemonomer from methanol and toluene. The operating conditions in the reactor performance tableare the temperature, pressure, conversion and yield for an equimolar feed of methanol and tolueneto the reactor.

The proposed production rate is 300,000 metric tons per year of styrene monomer. Whatis the production rate in kgmol/hr for a 95% onstream time (8,320 hours per year)? Study themathematical algorithm and HYSYS simulation algorithm for a reactor in Appendix H to

determine what variables must be specified in order to simulate your reactor. Your study shouldreveal that the feed flow rate and composition to the reactor must be specified instead of the totaland component flow rates out of the reactor. Manually estimate the feed flow rate based on 100 percent conversion, no side reaction for ethylbenzene, and the proposed styrene production rate inkgmol/hr. Please document your calculations.

Using your estimated feed flow rate, run HYSYS to simulate the conversion reactor forthe production of styrene from toluene and methanol. What chemical components are in thereactor effluent stream and why? The conceptual model for this reactor is as follows:

S11S10R1

Use the stream and equipment labels above in your HYSYS process flow diagram (PFD). For theconversion reactor, two chemical reactions will occur—one producing styrene monomer and theother ethylbenzene. Please note that the HYSYS conversion of toluene for the first reaction isequal to [overall conversion*yield] at a specific inlet temperature and that for the second reactionis equal to [overall conversion*(1.00-yield)]. After completing this simulation with the estimated

feed flow rate, use the HYSYS Adjust operation to modify the given reactor feed in order toobtain the desired production rate of styrene monomer in kgmol/hr. To learn how to apply the

Adjust operation, access the electronic version of the HYSYS Reference Manual from the

Start/All Programs menu in Windows.

After completing the above assignment, supply the HYSYS flowsheet with a materialstream table that includes the actual volumetric flow rate, mass density, and molecular weight.

You can use the Workbook/Setup… menu option to add these three items to the table. Also,include a composition table on the flowsheet PFD. The two tables can be added to the PFD by

clicking the right mouse button on the PFD. Using the HYSYS text capability, you must add atitle, the assignment number, the reactor inlet temperature, your name, and the date to theflowsheet. See Tutorial 2.9 for directions on text documentation. Finally, print the datablock forthe reactions only by clicking the right mouse button when the cursor is over the reactor icon.

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Problem SM.2

Reactor Effluent Cooling/Decanting Section

In Problem SM.1, you simulated the reactor in the styrene monomer project using data

provided by the Research and Development Department of BEEF, Inc. The reactor R1 has only

one effluent stream, the vapor stream S11. Using physical properties such as critical temperature,critical pressure, and normal boiling temperature for each reaction component, verify and

document that S11 should indeed be a vapor stream. To verify the stream phase, it may help tothink of a phase (PT) diagram for each component. Physical properties of various chemicalcomponents are given in Appendix A.

A global flowsheet for a chemical process depicts simply the raw materials entering theflowsheet and the product, byproducts and wastes leaving the flowsheet. Appendix A gives a block flowsheet for the chemical process of converting toluene and methanol to styrenemonomer. A global flowsheet for the styrene monomer chemical process is shown below.

Raw Materials Reactor Effluent SeparationSequence

Recycle Reactants

Off Gas

Byproduct

Pure Product

Wastewater

This global flowsheet shows the reactor producing an effluent stream, which must be separated to purify the product. The reactor effluent goes through a separation sequence in which the off gas,

byproduct, pure product and waste are isolated. Unreacted raw materials are also separated in thesequence. The reactants are then recycled to the reactor. The number of process exit streams— off gas, pure product, waste, etc.—determines the number of separation units required in thesequence. As a rule of thumb, for multiple process exit streams, the number of requiredseparation units is between one and the number of exit streams.

The first step in the design of a separation sequence is to decide what the first separationunit is. Some types of separation are phase splitting, distillation and extraction. Phase splits arethe cheapest method of separation. Think of your separator funnel in organic chemistry labs tovisualize a phase split. Therefore, if possible, a phase splitter is the first separation unit in theseparation sequence.

If the reactor effluent is all vapor, it must be cooled to allow a phase separation to take place. In the styrene monomer project, the reactor effluent is cooled to allow the formation ofthree distinct phases, the vapor phase and two immiscible liquid phases. The two liquids are anorganic phase and an aqueous phase. To predict which components each phase contains,remember that “like dissolves like.” The organic phase contains the organics of toluene,ethylbenzene, and styrene monomer. The methanol partitions between both the organic phase

and the aqueous phase. More information on the three-phase separator is given in the Design

Data section of Appendix A. A three-phase separator is also known as a decanter. Appendix J

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Problem SM.2

provides a mathematical description of how a decanter is modeled. Also, Appendix G describeshow a cooling operation functions.

You now know that the reactor effluent must be cooled from a vapor stream to atemperature at which three phases exist. You must determine to what temperature the stream iscooled to produce the phase separation. The cooling is typically carried out by a heat exchangerin which the effluent is cooled by a water stream. The cooling water is not directly mixed withthe effluent. Rather, the two streams exchange heat so that the hot effluent is cooled while thecold water is heated. It is unfeasible to design a heat exchanger that cools the hot stream theentire way to the temperature of the cold stream. Such a heat exchanger would be infinitely largein area. Typically, it is assumed that the hot stream is cooled to within 5 to 10°C of the initialcold stream temperature. As a rule of thumb, the cooling water is supplied at 31°C, so the reactoreffluent is cooled to about 38°C. At 38°C three phases may exist, and they could be separated ina decanter.

The next step in the styrene monomer project is to simulate the first separation unit. UseHYSYS to simulate the effluent cooling and three-phase separator. The conceptual model for thereactor, cooler, and decanter is as follows:

S15

S13

S14AR1

S10 S11 S12

E3

E3F3

Use the stream and equipment labels above in your HYSYS process flow diagram (PFD).

Account for pressure drops through the reactor (R1), cooler (E3), and decanter (F3) using the datain Appendix A. Begin with the HYSYS solution of Problem SM.1 provided in the Blackboard

CHEG 200 course under the Assignments section. Your instructor will give you directions onhow to access this folder.

At what temperature in °C does two phases (vapor-liquid) start to occur on cooling?Does three phases (vapor-liquid-liquid) start to occur on cooling? On a molar basis, what fraction

of Stream S11 after cooling to 38°C goes to the vapor phase of the decanter? To the organic

phase? To the aqueous phase? On a mass basis, what fraction of Stream S11 after cooling to38°C goes to the vapor phase of the decanter? To the organic phase? To the aqueous phase?

After completing the above assignment, supply the HYSYS flowsheet with a workbook

table for cooling and decanting at 38°C. A workbook table can be added to the PFD by clickingthe right mouse button on the PFD and using the drop-down menu. Also, use the HYSYS text

capability to add a title, the assignment number, your name, and the date to the PFD. SeeTutorial 2.9 for directions on text documentation. Finally, supply the three-phase-separatordesign and worksheet datasheets.

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Problem SM.3

Methanol Recycle Purification Section

In Problem SM.2, you simulated the first separation operation, a three-phase decanter, inthe separation sequence of the styrene monomer project. In Problem SM.3, you will simulate the

next operation in the separation sequence, a distillation column. A distillation column uses thedifference in boiling points to separate the components of a stream. Think of a liquid mixture oftwo components with each component having different boiling points. If the mixture is heated toa temperature between the boiling points of the two components, the more volatile component(lower boiling point) vaporizes while the less volatile component (higher boiling point) remainsin the liquid phase. By collecting the vapor, you have effectively separated the binary mixtureinto two single phases, the vapor phase containing the more volatile component and the liquid phase containing the less volatile. The same principle can be used to separate streams with morethan two components into two mixtures with fewer components. All of the more volatilecomponents will vaporize, and all of the less volatile components will remain in the liquid.Exactly where the separation occurs, i.e. which components vaporize and which do not, dependson the temperature that the original mixture is heated to.

A distillation column is a series of stages or trays where each act as a separator accordingto boiling points as described above. A column separates a liquid feed stream into two liquidstreams, the distillate and bottoms. The temperature of each tray gradually decreases as you goup the column. A reboiler at the bottom of the column heats the liquid in the column to asaturated vapor. This vapor then rises through the trays of the column. As the temperaturedecreases going up the column, the less volatile components begin to condense and fall backdown through the column. By the time you reach the top of the column at the lowesttemperature, only the most volatile components are vapors and exit the column. This vaporstream is condensed to a saturated liquid and then split into a reflux stream and distillate stream.The reflux stream is sent back to the column. The less volatile components exit from the reboilerin the bottoms stream.

To consider distillation as a possible separation operation, you must determine the normal boiling points of the stream components in the feed stream to that column. Find the normal

boiling points (nbp) for all chemical components in the styrene monomer problem. List the

components and nbp in order of increasing boiling point in the table below. HYSYS containscomponent properties such as normal boiling point. To find a property value, view your

simulation fluid package and go to the Components page. Double click on the desiredcomponent in the current component list to open a window listing the component properties.

Find the tab that contains the desired property, here the Critical tab for normal boiling point at 1atm, and read the value and units.

To design a distillation column, you pick two components with adjacent boiling points, as

depicted in the diagram below. The more volatile component is called the light key (LK) and theless volatile component is called the heavy key (HK). The split in the column is between thesetwo key components. A perfect separation means that all of the LK would be in the distillate, andall of the HK would be in the bottoms. However, like in the case of a three-phase separator, perfect separation is unfeasible. An infinite number of trays in the distillation column would berequired to perform a perfect separation. Therefore, a separation level is chosen for the column.Most of the LK exits the column through the distillate, with a little in the bottoms, and most ofthe HK exits the column through the bottoms, with a little in the distillate. The distillate containsall components more volatile than the LK (non-LK's), and the bottoms contains all components

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Problem SM.3

less volatile than the HK (non-HK's). A simple diagram to show the component flows is shown below.

non-LK'smost LK

little HK

little LK most HKnon-HK' s

non-LK'sLK

HKnon-HK' s

Column

In the table below, where you entered the components and their boiling points, you are to

indicate the feed type of each component, i.e. tell whether each component is a LK, HK, non-LKor non-HK. Indicate the distribution of each component in the table by stating which stream(s)(distillate and/or bottoms) the component appears in, and in what relative amount, such as all,most or little. Remember that the column is being designed to separate methanol from water.

ComponentNormal Boiling

Point, CFeed Type Distribution

A detailed description of a simple distillation column is given Appendix L of thishandbook. What are the three main parts of a distillation column? The overall mathematicalmodel for a column consists of a series of smaller math models, one for each of these column parts. In what order are the overall mathematical model equations solved in the columnalgorithm? How does the column algorithm differ from the HYSYS simulation algorithm?Why?

The diagram for the distillation column used for Problem SM.3 is given below. Itcontains a partial condenser and several stages above and below the feed stage. However, thesimple distillation column in Appendix L has a total condenser, meaning the entire vapor comingoff the top of the column is converted to a saturated liquid. To achieve this, all of the componentsare assumed to be condensable. However, the column in the styrene monomer problem containshydrogen, which is non-condensable. Note hydrogen's extremely low boiling point in your tableabove. Because the column contains hydrogen, a partial condenser is used which will allow the

hydrogen to exit the column as a vapor in stream V.

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Problem SM.3

Reboiler

QR

QC

Condenser

Stages

Feed

F FeedStage

DistillateD

StagesRefluxRF

Bottoms

B

V

DistillateVent

The use of a partial condenser instead of a total condenser means that one more variable

must be specified for HYSYS to simulate the column. The functional form for the HYSYSsimulation algorithm of this column is

,, , , , , , , , , , ,V D B C R F D B S FS B LK

Q Q column P P N N R x VR⎡ ⎤ ⎡ ⎤Ψ Ψ Ψ = Ψ⎣ ⎦⎣ ⎦

where is the condenser energy rate or duty, is the reboiler energy rate or duty,QC

Q R

Pi is the

pressure of stream i, N S is the number of column stages, N FS is the feed stage number, R is the

reflux ratio,, B LK

x is the mole fraction of the light key (LK ) in the bottoms, and VR is the vent

ratio. The reflux ratio of R is the reflux flow (RF) rate over the distillate (D) flow rate. The ventratio of VR is the distillate vent flow (V) over the feed flow (F). The vector Ψ

i is a short

notation to represent the temperature, pressure, flow rate, and chemical composition ofstream i.

Shortcut methods exist to estimate column design variables like N S , ,and R. To

solve the rigorous HYSYS distillation column, the number of column trays, the tray at which thefeed enters the column, and three other variables must be specified. For this problem you will usethe reflux ratio, the mole fraction of methanol in the bottoms, and the vent ratio as the three othervariables. A shortcut analysis has already been performed on the column, and the followingvalues were found:

FS N

Number of stages = 24Feed Stage = 14Reflux ratio = 3

LK in bottoms = 0.001 mol. frac.Vent Ratio = 1.0e-4

These estimated variables can then be used as inputs to the rigorous distillation column inHYSYS. The shortcut analysis found the first three items based on a specified mole fraction forthe light key in the bottoms stream.

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Problem SM.3

Begin your HYSYS simulation for the methanol/water column from the HYSYS solution

to Problem SM.2 located in the Blackboard CHEG 200 course under the Assignments section.Your instructor will give you directions on how to access this folder. This SM.2 solution nowincludes a valve and heater to prepare the aqueous stream for distillation. It also has an

unattached rigorous distillation column in the PFD. Use the labels given below to define therigorous distillation column.

S16

S17

C3

QCC3

S18

QRC3

S17V

Double click the rigorous distillation column in the PFD, to open its property window. On the

Design/Connections page, enter the column name, the material and energy stream names, and thenumber of stages and feed stage found from the shortcut method. Make sure the partial

condenser is chosen so you can name the vent stream S17V. Enter 123 kPa for the condenser

pressure and 134 kPa for the reboiler pressure. The pressures of every stage between thecondenser and reboiler will be calculated by HYSYS. Go to the Design/Monitor page and entervalues in the “Specified Values” column for the reflux ratio, mole fraction of the LK in the

bottoms, and the vent ratio. On the Design/Monitor page, the degrees of freedom box in thelower right corner currently show three. It must be zero in order for the column to be solved. Tomake this zero, you must tell HYSYS which specifications to use. Click the boxes to the right ofthe values you specified to make the reflux ratio, mole fraction of the LK in the bottoms, and thevent ratio active specifications. Note that a fourth specification for the mole fraction of the heavykey in the distillate must be inactive.

Once enough variables are specified to satisfy the degrees of freedom, the column williterate to find a solution. The green converged message will show up in your column window to

indicate the rigorous distillation simulation is solved. Sometimes the column calculations maynot converge. When this happens, deactivate the LK specification and active the HKspecification. Then, run the calculations again to see if the distillation simulation will converge.

How was the value for the vent ratio estimated? What are the distillate, vent, and bottoms flow rates in kg/h? What are the mole fractions of the HK in the bottoms and the LK in

the distillate? Using the Performance/Plots page, print plots of the temperature profile andcomposition profiles of the LK and HK in the column. Hand in your PFD and the design andworksheet datasheets for C3.

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Problem SM.4

Toluene Recycle Purification Section

In Problem SM.3, you simulated the distillation column that recovered methanol in theaqueous stream from the three-phase decanter. This recovered methanol will eventually berecycled in a later problem. The next operation in the separation sequence of the styrenemonomer project is another distillation column. In Problem SM.4, you will simulate a distillationcolumn to separate reactants from products in the organic stream leaving the three-phasedecanter. The organic stream contains both methanol and toluene that are to be recycled to thereactor. The organic stream also contains the styrene monomer product and the byproductethylbenzene.

As with column C3 in Problem SM.3, the first step in simulating the distillation column

is to find the normal boiling points (nbp) for all chemical components in the styrene monomer

problem and list the components and nbp in order of increasing boiling points in the table below.To find the normal boiling point of the components in HYSYS, view your simulation fluid

package and go to the Components page. Double click on the desired component in the current

component list to bring up a window listing the component properties. Find the tab that containsthe desired property, here the Critical tab for normal boiling point, and read the value and units.

In the table below, where you entered the components and their boiling points, you are toindicate the feed type of each component, i.e. tell whether each component is a LK, HK, non-LKor non-HK. Indicate the distribution of each component in the table by stating which stream(s)(distillate and/or bottoms) the component appears in, and in what relative amount, such as all,most or little. If necessary, refer to the Problem SM.3 handout to refresh yourself with theconcept of key components. Remember that the column is being designed to separate thereactants from the products.

Component Normal BoilingPoint, C

Feed Type Distribution

As in the case of methanol column C3, the feed to this column, called C1, contains the

uncondensable, hydrogen, which means a partial condenser must be used. Column C1 is depictedon the next page. What is the functional form for the HYSYS simulation algorithm for thiscolumn? Define each of the variables in this functional form. (HINT: Refer to the Problem SM.3

handout)

Shortcut methods exist to estimate column design variables like number of stages, feedstage location, and reflux ratio. To solve the rigorous HYSYS distillation column, the number ofcolumn trays, the tray at which the feed enters the column, and three other variables must bespecified. For this problem you will use the reflux ratio, the mole fraction of toluene in the

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Problem SM.4

bottoms, and the vent ratio as the three other variables. A shortcut analysis has already been performed on the column, and the following values were found:

Number of stages = 28Feed Stage = 13Reflux Ratio = 3LK in bottoms = 0.001 mol. frac.

5Vent Ratio = .0e-3

These estimated variables are the inputs to the rigorous distillation column in HYSYS.

Begin your HYSYS simulation for the column from the HYSYS solution to Problem

SM.3 located in the Blackboard CHEG 200 course under the Assignments section. Yourinstructor will give you directions on how to access this folder. The SM.3 solution now includesa valve and heater to prepare the organic stream for distillation. It also has an unattached rigorous

distillation column in the PFD to process the organic stream (S22). Use the labels given below todefine the rigorous distillation column.

S22

S23

C1

QCC1

S24

QRC1

S23V

Double click the rigorous distillation column in the PFD, to open its property window. On the

Design/Connections page, enter the column name, the material and energy stream names, and thenumber of stages and feed stage found from the shortcut method. Make sure the partial

condenser is chosen so you can name the vent stream S23V. Enter 79 kPa for the condenser pressure and 99 kPa for the reboiler pressure. The pressures of every stage between the

condenser and reboiler will be calculated by HYSYS. Go to the Design/Monitor page and enter

values in the “Specified Values” column for the reflux ratio, mole fraction of the LK in the bottoms, and the vent ratio. On the Design/Monitor page, the degrees of freedom box in thelower right corner currently show three. It must be zero in order for the column to be solved. Tomake this zero, you must tell HYSYS which specifications to use. Click the boxes to the right ofthe values you specified to make the reflux ratio, mole fraction of the LK in the bottoms, and thevent ratio active specifications. Note that a fourth specification for the mole fraction of the heavykey in the distillate must be inactive.

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Problem SM.4

Once enough variables are specified to satisfy the degrees of freedom, the column williterate to find a solution. The green converged message will show up in your column window toindicate the rigorous distillation simulation is solved. Sometimes the column calculations maynot converge. When this happens, deactivate the LK specification and active the HKspecification. Then, run the calculations again to see if the distillation simulation will converge.

How was the value for the vent ratio estimated? Recall that the vent ratio is the

molar ratio of the vent stream flow rate to the feed stream flow rate. You can use the componentflow rates of the non-condensibles in the feed and the total feed rate to estimate the vent ratio.This estimation assume all non-condensibles (methanol and hydrogen) will exit the column in thevent stream.

What are the distillate, vent, and bottoms flow rates in kg/h? What are the mole fractions

of the HK in the bottoms and the LK in the distillate? Using the Performance/Plots page, print plots of the temperature profile and composition profiles of the LK and HK in thecolumn. Hand in your PFD and the design and worksheet datasheets for C1.

Colum n C1 is designed to separate the reactants from the products in order to recycle the

reactants. The C1 distillate stream contains the recycled reactants. The recycle stream must be prepared, in order to be mixed with fresh raw materials before entering the reactor. The fresh andrecycled reactant streams are mixed as saturated vapors at 570 kPa. Add a pump and heater to

distillate stream S23 to reach the saturation point at 570 kPa in stream S26 below. You mustdecide whether to heat the stream first, or to pump it first. Compressing a gas takes much moreenergy than pumping a liquid. Therefore, if you heat the stream to a saturated vapor first, extraenergy will be needed to compress the vapor to the desired pressure. As a heuristic rule, pumpthe liquid first and then heat to a saturated vapor. Don't forget to account for the pressure dropacross the heater using the data in Appendix A. The desired pressure of 570 kPa is the final pressure, after the pump and heater. Use the following labels in your simulation:

E5

P4

C1

S23

QE5

S26S25

WP4

Hand in the design and worksheet datasheets for P4 and E5.

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Problem SM.5

Toluene/Methanol Feed Preparation Section

In Problem SM.1, you simulated the reactor to produce styrene monomer from tolueneand methanol. In SM.1 you assumed a single reactor feed stream that contained the two reactants

at the optimum reactor conditions of 512.5°C and 400 kPa. Most likely, the raw materials (i.e., thetwo reactants) will actually be available individually at some other conditions. In this case, puremethanol and pure toluene are both available at ambient conditions, 25°C and 1 atm. In ProblemSM.5, you are to simulate the preparation of the methanol and toluene.

The pure methanol and pure toluene streams are to be mixed as saturated vapors at 570kPa. This means that each raw material must be compressed and heated separately before beingmixed. Compression of a gas requires considerably more energy than compression of a liquid.As a general heuristic rule, you should first pump the liquid to the desired pressure and then heatthe high-pressure liquid to a saturated vapor. You are to simulate the preparation of the two pureraw material streams, one for methanol and one for toluene, from ambient conditions to saturatedvapors at 570 kPa. From Problem SM.1, the amount of reactants needed to produce 300,000

metric tons per year of styrene monomer was determined to be 584 kgmol/h of methanol and 584kgmol/h of toluene.

You are to begin a new case file for the HYSYS simulation in this problem, using the

PRSV property package with two chemical components—toluene and methanol. You canassume a 75% adiabatic efficiency for the pumps. After you have pumped and heated the rawmaterial streams to the desired conditions, you are to mix the two streams to create a singlereactor feed stream. Use the following labels in your HYSYS simulation:

S4

methanolE2

S6

S1toluene

S2

P1

P2

S5

E1

S3

S7M1

E2

E1WP1

WP2

Using the Performance/Plots page, produce graphs of temperature versus heat duty (T vs.

Q, a cooling curve) for heater E1 and also heater E2. Be sure to include the liquid, vapor-liquid, andvapor regions in each plot. On each cooling curve, label the two sensible heat regions and the

latent heat region. What are the dew-point and bubble-point temperatures of stream S2 and also

stream S5? What is unique about the dew point and bubble point for each pure chemicalcompound? Explain.

Using the Gibbs phase rule (see F&R, 3rd Ed., p. 247), find the degrees of freedom for when a phase transition occurs. How does a cooling curve depict this transition? (HINT: Look at the slope of

the curve during a phase transition.) Hand in your PFD and your two cooling curve graphs.

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Problem SM.6

Recycle Mixing and Preheating Section

In Problem SM.5, you simulated the compression and vaporization of the two fresh

reactant streams, pure toluene S1 and pure methanol S4, for the styrene project. The feed to the

reactor also contains recycled material from columns C1 and C3, as depicted in the blockflowsheet of Appendix A. The recycle streams must be mixed with the fresh reactant stream before entering the reactor, creating a recycle loop in the process. In Problem SM.6 you are tosimulate the recycle loop.

Begin with the solution to Problem SM.5 located in the Blackboard CHEG 200 course

under the Assignments section. Your instructor will give you directions on how to access thisfolder. The SM.5 solution now includes the fresh reactant compression, vaporization, and

mixing, as well as the rest of the process flowsheet from the reactor to the distillation columns C1

and C3. However, the fresh reactant stream is not yet connected to the reactor. The recycledstreams from the distillation columns are pumped and heated to bring them to saturated vapors at570 kPa before mixing with the fresh reactants. Create another mixer in the flowsheet to combine

the fresh reactant stream with the two recycle streams. This stream then must be prepared to enterthe reactor. Add a heater to heat the stream to the reactor temperature 512°C. The heater used to

reach such a high temperature is a fired heater, basically a furnace that burns natural gas. Use

the usual HYSYS heater with a pressure drop of 170 kPa. This pressure drop will set the reactor

feed stream S9 to the reactor pressure of 400 kPa. Use the following labels in the PFD:

S9S8

FH1M2S7

QFH1

S26

S21

Now stream S9 represents the reactor feed. However, the process state of S9 is calculated

by assuming the conditions of reactor feed S10, which you did in Problem SM.1. To close the

recycle loop, you must verify that the process state of stream S9 exiting the fired heater FH1 is

identical to the reactor feed stream S10. Open the property windows of streams S9 and S10 andcompare their temperatures, pressures, flow rates, compositions, and heat flows. The iterativemethod of successive substitution is used to converge the process state of the reactor feed stream.

To assume a new state for the reactor feed stream of S10, copy the conditions of S9 into S10

using the Define From Other Stream… button in the property window of stream S10. Thisaction will cause HYSYS to recalculate all of the process units and produce a different calculated

S9. The process states of S9 and S10 should now be closer to each other. Again copy theconditions of S9 into S10 to assume a new process state for the reactor feed stream. You could

continue this process, manually performing the successive iterations until the process state of S9

is identical to that of S10. After performing three (3) manual iterations, you are to hand in the

worksheet datasheets for streams S9 and S10.

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Problem SM.6

HYSYS has an operator that will perform automatically the successive iterations for you.

Add a recycle operation between streams S9 and S10 as shown below.

RCY-1

RS9 S10

HYSYS will now automatically iterate on the process state of these two streams to solve therecycle loop. When the recycle operator has converged, you will get a green converged messageat the bottom of the recycle property window. After convergence, what are the component molar

and mass flow rates of the reactor feed, stream S10?

Hand in your PFD and the design and worksheet datasheets for the recycle operator RY.

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Problem SM.7

Styrene Monomer Purification Section

In Problems SM.1 through SM.6, you simulated the production of styrene monomer frommethanol and toluene, including the separation and recycle of unused reactants. In the resultingflowsheet produced by solving these problems, the bottoms stream from the separation column

C1 contains both the product styrene monomer and the by-product ethylbenzene. A distillationcolumn is needed to purify the desired styrene monomer to produce a product stream that meetsthe design specification. In Problem SM.7, you are to simulate the purification of the styrenemonomer.

Begin with the solution to Problem SM.6 located in the Blackboard CHEG 200 course

under the Assignments section. Your instructor will give you directions on how to access thisfolder. The SM.6 solution now includes a valve and cooler to prepare the organic stream from

the decanter for separation, as well as column C2 for the separation of ethylbenzene from styrene

monomer. You need to provide the specifications to simulate the separation in column C2 thatoperates with a total condenser. The specifications you will use are: number of trays, feed tray

location, reboiler and condenser pressures, reflux ratio, and light-key (LK ) composition in the bottoms. The number of trays and feed tray location are already specified in the SM.6 solutionfile. The following information is given to you:

Reboiler Pressure = 83 kPaCondenser Pressure = 31 kPaReflux Ratio = 35

You must determine the LK composition in the bottoms. Remember that column C2 is beingdesigned to separate ethylbenzene from styrene.

The LK composition in the bottoms is a mass fraction, and the bottoms stream contains

the product styrene monomer. Using the technical data provided in Appendix A, determine thedesign specification of the LK in the bottoms stream. What is the LK mass fraction in the bottoms, and what is the feed ratio? Finally, enter this column specification and the other ones

above for C2 and then have HYSYS solve the column operation for you.

The distillation column produces distillate and bottoms streams at pressure belowambient. The product and by-product must be stored at ambient conditions until they are neededfor sales in the marketplace. Simulate the pumping and cooling of both streams to ambientconditions, accounting for a pressure drop in each cooler using information provided in AppendixA. Use the labels given in the diagram below:

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Problem SM.7

E7

E7

WP6

P6

P5 E6

QE6WP5

S32 S33

S31S30S28

S27 C2

S29

Once you have completed the above simulation of the entire flowsheet, you are to perform an overall energy and material balance check. To help you perform these balances, use

the tables that are provided on the last page of this problem assignment.

What are the material relative imbalances (%RIB’s) on a total mass and molar basis forthe entire flowsheet? What is the energy relative imbalance (%RIB’s) for the entire flowsheet?

Show your calculations. Hand in your completed tables, the PFD, and the C2 design andworksheet datasheets.

Finally, calculate the net profit for the production of styrene monomer from toluene andmethanol. The net profit in $/yr is:

sales of

product +sales of

by-product +fuel-value

credit -cost of

raw mat'ls -cost of

utilities -annualized

capital cost

Use the economic information provided in Appendix A for the necessary sales and cost prices andthe fuel-value credit. To get the fuel credit, duplicate the vapor streams from the decanter and theone distillation column in the PFD, and then mix these duplicate streams to form one off-gasstream, which will be given a credit as fuel. To determine this credit, you will need to find thelower heating value of this off-gas stream. HYSYS has already calculated this heating value.

You need to add it to the HYSYS Workbook window through the Workbook/Setup menuoption.

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Problem SM.7

Unit Operation Energy Flows In

Unit Operation Duty or Work, kJ/h Unit Operation Duty or Work, kJ/hP1 CE3

E1 P3

P2 E4

E2 P5

FH1 P6

P4 C1 reboiler

E5 C2 reboiler

CE1 C3 reboiler

Distillation column reboiler and condenser duties can be found on the Summary tab of the column property window.

Unit Operation Energy Flows Out

Unit Operation Duty, kJ/h Unit Operation Duty, kJ/h

E3 C1 condenser

CE2 C2 condenser

E6 C3 condenser

E7

Stream Energy and Material Flows

Duty or Work Energy Flow, kJ/h Material Flow, kg/h In or Out?

S1

S4

S13S23V

S18

S31

S33

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Appenidx A. Styrene Monomer Production

Introduction†

A two-step process starting with benzene and ethylene produces 90% of the styrene

monomer marketed in the United States. First, benzene is alkylated with ethylene to formethylbenzene. After purification, the ethylbenzene is catalytically dehydrogenated to produce

styrene. The dehydrogenation step is endothermic and requires a large quantity of steam mixedwith the ethylbenzene to maintain the desired reaction temperature, to depress coking of thecatalyst, and to dilute the reaction concentration to enhance the reaction equilibrium.

Chemists in our Research and Development (R&D) Department of BEEF, Inc. havediscovered a catalyst, which will produce styrene from toluene and methanol in one step, andsteam addition is not required. Some byproduct ethylbenzene is also produced which can be soldto conventional styrene producers. This catalyst discovery might give our clients the opportunityto develop a new, low-cost route to styrene.

Proposed Styrene Process

Chemical engineers in our R&D Department of BEEF, Inc. have done some pilot-plantstudies on this new one-step process. They have defined the following preliminary blockflowsheet for this process:

waste water

aqueous

organic

columncolumn

column

styrene monomer

ethylbenzene

H2 fuel

decanter

methanol recycle

toluene recycle

methanol recycle

reactor furnace

methanol

toluene

In this flowsheet, toluene and methanol feeds at 25°C and 1 atm are compressed and heated too

saturated vapors at 570 kPa. These two feeds are then mixed with a toluene recycle and amethanol recycle ( both of which are saturated vapors at 570 kPa) to form the feed stream to the reactor.This feed stream is superheated in a fired furnace and then fed to the catalytic reactor where thefollowing vapor-phase reactions take place:

____________________† The material in this appendix has been extracted from the 1985 Student Contest Problem — Styrene

from Toluene and Methanol published by the American Institute of Chemical Engineers (AIChE). Thereactor performance table was modified by adding a fifth temperature column of 540ºC.

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C7H8 + CH3OH ↔ C8H8 + H2O + H2

toluene methanol styrene water hydrogen

C7H8 + CH3OH ↔ C8H10 + H2O

toluene methanol ethylbenzene water

In a preliminary design analysis, one could assume that other byproduct formation and polymerization of styrene monomer are negligible and that the catalyst does not coke ordeactivate with time.

The reactor effluent stream is condensed with cooling tower water and cooled to 38°C,forming three phases—vapor, organic, and aqueous—in a decanter. The vapor stream from thedecanter contains mostly hydrogen, and it could be used as a fuel. The aqueous stream contains primarily methanol and water, and it is sent to a methanol distillation column. This column’s product stream is the recycled methanol, while its bottoms stream is wastewater, which iseventually discharged at 25°C and 1 atm. The organic stream from the decanter contains mostlytoluene, ethylbenzene, and styrene monomer. It is sent to a toluene distillation column. This

column’s product stream is the recycled toluene stream containing some methanol, while its bottoms stream contains mostly ethylbenzene and styrene monomer, which are sent to the styrenedistillation column. In the styrene column, the product stream is mostly ethylbenzene, and the bottoms stream is mostly styrene monomer. Both of these streams are then cooled to 25°C and 1atm before each enters a storage tank.

Technical Data

A. Reactor Performance

Chemical engineers in our R&D Department have taken the following data fordetermining the adiabatic reactor performance. Linear interpolation can be used betweentemperatures for intermediate values.

Inlet Temperature, °C 480 495 510 525 540

Inlet pressure, kPa abs. 400 400 400 400 400

Conversion 0.68 0.71 0.76 0.82 0.88

Yield 0.87 0.83 0.78 0.72 0.66

Rate 36 73 130 190 250

Conversion = moles toluene reacted/moles toluene fed.Yield = moles styrene formed/moles toluene reacted.Rate = gmoles toluene reacted/m3 catalyst/min.

In collecting these reactor performance data, the pilot-plant experiments used only stoichiometricfeed to the reactor. Therefore, any design study should be based only on stoichiometric feed (i.e.,

equal moles of toluene and methanol).

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B. Physical Properties

Some physical properties are given in the table below. These values have been roundedoff for manual calculations. All pressures are absolute.

PropertyMethanol Water Toluene

Ethyl- benzene Styrene Hydrogen

Molecular Weight 32 18 92 106 104 2

Normal Boiling Point, °C 65 100 111 136 145 -253

Critical Temperature, °C 239 374 321 344 364 -240

Critical Pressure, kPa 8094 22054 4233 3599 3674 1296

Critical Compress. Factor 0.230 0.232 0.270 0.262 0.252 0.318

Ideal Gas at 25°C, kcal/mol:Heat of Formation -48.1 -57.80 11.95 7.12 35.22 0.00Free Energy of Formation -38.8 -54.64 29.16 31.21 51.10 0.00

C. Thermodynamic Model

For a preliminary design study, all necessary thermodynamic calculations for physical properties (such as density and molar enthalpy) and for phase equilibria (such as vapor-liquid or vapor-liquid-

liquid) can be done using an equation of state. The Peng-Robinson Stryjek-Vera (PRSV) equationof state is recommended for the analysis of the manufacture of styrene monomer from toluene andmethanol. The PRSV equation is an improvement on the Peng-Robinson (PR ) equation of state,and it extends the application of the PR method to moderately non-ideal systems.

Design Data(Including Simplifying Assumptions)

A. Material Balance

The proposed plant capacity is 300,000 metric tons per year of crude styrene monomer,which includes 300 ppm of contained ethylbenzene. The onstream time is 95% (8,320 hours per

year ). Yield losses due to trace byproducts can been ignored. Other assumptions are:

1.

Impurities in purchased methanol and toluene are negligible.

2. Water, ethylbenzene and styrene monomer recycled to the reactor feed are at smallenough concentrations to pass through as inerts.

B. Three-Phase Separator

The reactor effluent condensed with cooling-tower water forms three phases: vapor,organic, and aqueous phases (Phase phenomena are given below). In a preliminary design study, thevapor phase could be given a fuel-value credit. The organic phase must be processed to recoverunreacted toluene and methanol for recycle and to purify the styrene and ethylbenzene streams tomeet design specifications. Also, the aqueous phase must be processed to recover unreactedmethanol.

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The lowest acceptable process outlet temperature for all water-cooled heat exchangers is38°C and is limited by the cooling tower water supply temperature.

Vapor Phase

• Phase equilibrium for all condensibles in the three-phase decanter areapproximated using the PRSV equation of state.

• The off-gas will be given a credit as fuel at its lower heating value. This value isthe calories evolved from complete combustion of all of the components in thestream at 25°C, when the final state of all of the water formed and originally present in the fuel is vapor.

Aqueous Phase

• Except for methanol, negligible organics will partition into the aqueous phase.

• Methanol is to be recycled as a saturated vapor at 570 kPa.

Organic Phase

• Negligible water will partition into the organic phase.

• Mostly methanol partitions into both the organic and aqueous phases.

• Toluene/methanol are to be recycled as a saturated vapor at 570 kPa.

C. Distillation

Nominal atmospheric distillations will operate at 136 kPa (k = kilo, Pa = Pascals) top tray pressure and 123 kPa condenser outlet pressure. Avoid column-operating pressures abovenominal atmospheric. Allow 5 kPa pressure drop between the top of the column and the

condenser outlet for vacuum columns.

Do not exceed 145°C in any column with more than 50 mass % styrene monomer (SM) inthe bottoms, in order to minimize SM polymerization.

Use the shortcut methods of Fenske for minimum stages, Underwood for minimumreflux, and Gilliland’s correlation for operating reflux before doing a rigorous columncalculation.

The feed, distillate, and bottoms streams of a distillation column are to be saturatedliquids.

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D. Design Specifications

Some design specifications for the aromatic and wastewater streams are:

Recycle Methanol No specified limit on toluene.Recycle Toluene No specified limit on methanol.

4 wt % EB maximum.5 wt % maximum for sum of EB and SM.

EB Byproduct 0.8 wt % toluene maximum.3 wt % SM maximum.

Crude SM Product 300 ppm EB maximum.(ppm is parts per million by weight)

Waste Water Governmental standards on all pollutants.

The Environmental Protection Agency (EPA) standards for water pollution are given as themaximum parts per million ( ppm on mass basis) for any one day. These standards are: 80 ppm fortoluene, 60 ppm for methanol, 108 ppm for ethylbenzene, and 108 ppm for styrene monomer.

E. Equipment Pressure Drop

For a preliminary design study, the following pressure drops may be assumed:

Fired heater 66 kPa

Reactor 70 kPa

Heat exchangers* (shell and tube sides) 13 kPa

Condensers under vacuum 5 kPa

Other major equipment 13 kPa

Distillation Trays:1.0 kPa per theoret. stage for pressure columns.0.6 kPa per theoret. stage for vacuum columns.

*Includes condensers, vaporizers, interchangers and all otherexchangers except condensers operated under vacuum.

Negligible pressure drop through piping may be assumed.

F. Compression or Pump Efficiency

The isentropic compression efficiency can be assumed to be 80%. The combinedmechanical and electrical efficiency is approximately 90%.

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Economic Data

A. Manufacturing Costs

Since plant startup is targeted for 1998, the manufacturing costs given below are based onthat year. (Basis of units: K = thousands, M = millions, 1998 dollars)

Raw Materials: M ethanol $0.19/kilogramTol uene $0.42/kilogram

Credits: Off-gas from three-phase separator $3.10/M kilojoules

Utilities: Natural gas* $4.40/M kilojoules

Steam :2865 kPa, sat’d. $17.30/K kilograms625 kPa, sat’d. $12.20/K kilograms

Cooling water $0.03/K litersInlet temp., avg. 31°COutlet temp., avg. 41°C maximum

El ectricity $0.065/kWHCondensate and Boiler feed water $2.50/K liters

*Assume 90% efficiency for the fired heater fuel usage.Onstream time is 95% or 8320 hours per year.

B. Product Sales

The gross profit is an initial economic indicator. It is defined as the product sales plus

any credits minus the raw material costs. The product values given below are based on 1998 prices.

Product Values:Crude Styrene productEthylbenzene byproduct

$0.91/kilogram$0.57/kilogram

Forecasting costs over the lifetime of a new project is a difficult task. The cost data given hereare tentative and appropriate only for preliminary economic evaluations. All costs are for 1998and apply to the Houston Gulf Coast area, where the plant will be located.

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Appendix B. HYSYS Simulation Modules

The HYSYS software system is an integrated engineering environment for thedevelopment and analysis of chemical process flowsheets. It provides you with:

• steady-state modeling and optimization for process design, and

• dynamic modeling for process controllability and control strategy development.

HYSYS is licensed for educational use only in our university by Aspen Technology, Inc. ofCambridge, MA. This BEEF handbook focuses on steady-state modeling, often called chemical process simulation.

A chemical process flowsheet is a conceptual representation of the transformation of rawmaterials into products through a series of process unit operations connected by process streams.Appendices C, D, etc. present simulation modules for the material and energy balances of somestandard process unit operations. In general, a process unit transforms the material passingthrough it, and this transformation is represented by a set of algebraic equations, called amathematical model. This model presents the material balances, energy balance, andthermodynamic relationships for the process unit. Since the math model has more variables thanequations, its degrees-of-freedom (DOF) tells you the number of variables that must be specified

to solve the equations. The order in which the model equations are solved—the mathalgorithm—depends on which variables are specified.

In HYSYS more than one combination of specifications can be used to solve themathematical model of a process unit. For example, in a pump simulation you can specify theinlet stream and the outlet pressure or pressure drop. You could also specify outlet informationinstead of inlet. This type of specification is known in HYSYS as backward propagation.HYSYS can back-calculate for the inlet conditions of a process unit given the outlet conditionsand appropriate information to fulfill the degrees of freedom. This flexibility comes from theunderlying mathematical equations that exist for each process unit and the different ways theseequations can be solved.

HYSYS incorporates the mathematical models for many process unit operations andknows which mathematical algorithm of a process unit to use according to which variables youhave specified. Some of the physical operations supported by HYSYS are as follows:

• material stream

• energy stream

• component splitter

• compressor / expander

• cooler / heater

• heat exchanger

• LNG exchanger

•

mixer• plug flow reactor

• pipe segment

• pump

• reactor operations

• separator / 3-phase separator / tank

• separation column

• shortcut column

• solid separator operations

•

tee• valve

The HYSYS Reference Manuals describe these process units in detail but do not provide ananalysis of their mathematical models. These HYSYS manuals exist as Adobe Acrobat Reader

files. You can access them through the Windows Start/Run… prompt. Type in the “Open:”

box of the Run window \\eng-file1\engapps\Hysys-Docs and then click the OK button.

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Appendix B. HYSYS Simulation Modules

Appendices C, D, etc. of this handbook present the mathematical models and some oftheir math algorithms for ten standard process units, in order to help you understand how HYSYS(or any simulation package, including hand calculations) solves the material and energy balances ofthese process units. The process unit modules in these appendices are for the following flowsheetoperations:

Module† Description

Process Stream Contains chemical components flowing at a certain state

Stream Mixer Mixes two or more process streams to make one stream

Pump Increases the pressure of a liquid process streamValve Decreases the pressure of a process stream

Heater/Cooler Heats or cools a process stream

Chemical Reactor Reacts the chemical compounds to form desired productsTwo-Phase Separator Separates a process stream into vapor and liquid streams

Three-Phase Separator Separates a process stream into vapor, organic, and aqueous streams

Component Splitter Splits a process stream into two streams at different temperaturesDistillation Column Separate a process stream through a series of equilibrium stages

The format for each module has been standardized, in order to aid your learning process. Thisformat is as follows:

1.

Description2. Process Diagram3. Assumptions4. Mathematical Model5.

Variable Descriptions6. Mathematical Algorithms7. HYSYS Simulation Algorithms

The description explains the purpose of the process unit operation. The process diagram depicts

the flow of material and energy. The assumptions list the conditions under which themathematical model is applicable. The mathematical model presents the material balances,energy balance, and thermodynamic relationships for a process unit; that is, the algebraicequations that model a process unit simulation. The mathematical algorithms are representativeexamples of how the mathematical model could be solved for a specified set of variables thatsatisfies the degrees of freedom. The HYSYS simulation algorithms are representative examplesof what you can specify to do a process unit simulation. These examples include calculations for both forward and backward propagation of information flow. You may have to consult the HYSYS Reference Manuals to discover all of simulation algorithms supported by HYSYS for a process unit operation.

____________________† Microsoft Word (.doc) files and Acrobat Reader (.pdf) files are available on the departments network

file server (R:) in folder chem _ engineering/public/HYSYS Manual for all materials in this HYSYS

manual, including the modules in the appendices. Your instructor will give you directions on how toaccess this folder. If some equations in a Word document happen not to display correctly, then use the(.pdf) file version of the document instead.

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Appendix C. Process Stream Module

Description

This simulation module models a process stream containing material that is composed ofmultiple chemical compounds or components. A process stream moves (i.e., flows) this materialfrom one process unit operation to another in a process flowsheet, connecting the two. In a process simulation, the material in a process stream is assumed to have uniform temperature, pressure, flow rate, and composition. These four quantities are referred to as the process state ofa material stream. The flow rate and composition can be expressed in terms of molar, mass, orvolumetric quantities.

The mathematical model for a multi-component process stream is given below. In thismodel, the isothermal, single-phase stream has uniform and ideal mixing, no pressure drop, andno chemical reaction. The independent set of equations contains the relationships between molar,mass, and volumetric quantities, and the functions for pure component densities and molecularweights. To solve the equations in this model, (nc+3) design variables must be specified, asindicated by the degrees-of-freedom analysis below.

Many mathematical algorithms can be derived from this model to do the material streamcalculations. These algorithms differ in their given variables and their solution procedures. Twosuch algorithms are shown below. The first math algorithm is based on knowing the total molarflow rate and composition, while the second is based on knowing the component molar flow ratesonly. As indicated below, the second algorithm is just an extension of the first algorithm. Other possible mathematical algorithms for a single-phase stream supported by the HYSYS simulationsystem are summarized below.

This module closes with a brief overview of how HYSYS simulates a process materialstream that is multi-phase; that is, vapor and liquid coexisting in equilibrium within the stream.You may need to consult the HYSYS Reference Manuals for further details on multi-phaseequilibrium in a process material stream.

Process Diagram Assumptions

T

P

n

Z

i

i

i

i

T

P

n

Z

i

i

i

i

stream i

1. single phase2. isothermal3. no pressure drop4. uniform and ideal mixing5. no chemical reaction

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Mathematical Model

( )

( )

( ) ( )

( ) [ ]

( ) ( ) ( )

( )

[ ]

( )

1

2

3 , ,

1 1

4

5 , , ,

1 1 1

6

7 , ,

for 1, 2, ,

for 1, 2, ,

1/ /

molwt

ˆ ˆ1/ /

density , ,

/

i i i

i i i

nc nc

i i j j i j j

j j

j

nc nc nc nc

i i j j i j j i i j i j

j j j j

j i i

i j i j j

j nc

j nc

M m n

m V

M z M w M

M pure j

w y M c

T P pure j

w z M M

ρ

ρ ρ ρ

ρ

= =

= = =

=

=

=

=

= ⋅

=

′= ⋅

=

= ⋅

∑ ∑

∑ ∑ ∑ ∑

or

or or or

( ) ( )

( )

,

1

c=

( )

( )

( )

( )

8 , ,

9 , ,

10 , ,

11 , , ,

12 , , ,

13

for 1, 2, ,

for 1, 2, ,

for 1, 2, ,

for 1, 2, ,

for 1, 2, ,

for 1, 2, ,

/

ˆ

ˆ

ˆ

ˆ

i

i j i j j i

i j i i j i

i j i i j

i j i i j i j

i j i i j i j

j nc

j nc

j nc

j nc

j nc

j nc

y w

c z M

c w

n n z c V

m m w c V

ρ ρ

ρ

ρ

=

=

=

=

=

=

= ⋅

= ⋅

′ = ⋅

= ⋅ ⋅

′= ⋅ ⋅

or

or

( )

( )

, ,

14

15

# vars 10 9

# eqns 9 6

DOF 1 3

for 1, 2, ,

ˆ hmix , ,

ˆ

i j i i j

i i i i

i i i

nc

nc

nc

j ncV V y

H T P Z

E n H

= ⋅ +

= ⋅ +

= ⋅ +

== ⋅

⎡ ⎤= ⎣ ⎦

= ⋅

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Variable Descriptions

T i is the temperature of process stream i, K.

Pi is the pressure of process stream i, kPa.

ni is the bulk molar flow rate of the process stream i, kgmol/h.mi is the bulk mass flow rate of the process stream i, kg/h.V i is the bulk volumetric flow rate of the process stream i, m3/h.

M i is the bulk molecular weight of process stream i, kg/kgmol.

M j is the molecular weight of pure component j, kg/kgmol.

ρ i is the bulk mass density of process stream i, kg/m3.

ρ j is the mass density of pure component j at T i and P , kg/mi

3.

nc is the number of chemical components or compounds in the mixture.

zi j, is the bulk mole fraction of component j in process stream i, mol j/mol mix i.

wi j, is the bulk mass fraction of component j in process stream i, mass j/mass mix i.

yi j, is the bulk volume fraction of component j in process stream i, vol j/vol mix i.

,ci j

is the bulk molar concentration of component j in process stream i, kgmol/m3.

,i jc′ is the bulk mass concentration of component j in process stream i, kg/m3.

,

ni j

is the bulk molar flow rate of component j in process stream i, kgmol/h.

,mi j is the bulk mass flow rate of component j in process stream i, kg/h.

,V i j is the bulk volumetric flow rate of component j in process stream i, m3/h.

H i is the bulk molar enthalpy of process stream i, kJ/kgmol.

E i is the bulk energy or heat flow of process stream i, kJ/h.

Z i is the bulk mole fractions of all nc-components in stream i.

W i is the bulk mass fractions of all nc-components in stream i.

Y i is the bulk volume fractions of all nc-components in stream i.

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Mathematical Algorithm A

( )

( ) [ ]

( ) [ ]

( )

( )

( )

11 , ,

4

6

3 ,

1

1

7 , ,

for 1, 2, ,

for 1, 2, ,

for 1, 2, ,

for

, , , streama , , ,

1.

2. molwt

3. density , ,

4.

5.

6. /

i i i i i i i i

i j i i j

j

j i i

nc

i i j j

j

i i i

i j i j j i

j nc

j nc

j nc

m V W Y T P n Z

n n z

M pure j

T P pure j

M z M

m n M

w z M M

ρ

=

=

=

=

⎡ ⎤ ⎡ ⎤= ⎣ ⎦⎣ ⎦

⇐ ⋅

⇐

⇐

⇐ ⋅

⇐ ⋅

⇐ ⋅

∑

( )

( ) ( )

( )

( ) ( )( )

( )

( )

12 , ,

5 ,

1

2

8 , ,

13 , ,

9 , ,

10 ,

1, 2, ,

for 1, 2, ,

for 1, 2, ,

for 1, 2, ,

for 1, 2, ,

7.

8. 1/ /

9. /

10. /

11.

ˆ12. /

ˆ13.

i j i i j

nc

i i j j

j

i i i

i j i j j i

i j i i j

i j i i j i

i j i i

j nc

j nc

j nc

j nc

j nc

m m w

w

V m

y w

V V y

c z M

c w

ρ ρ

ρ

ρ ρ

ρ

ρ

=

=

=

=

=

=

⇐ ⋅

⇐

⇐

⇐ ⋅

⇐ ⋅

⇐ ⋅

′ ⇐ ⋅

∑

( )

( )

,

14

15

for 1, 2, ,

ˆ14. hmix , ,

ˆ15.

j

i i i i

i i i

j nc

H T P Z

E n H

=

⎡ ⎤⇐ ⎣ ⎦

⇐ ⋅

Mathematical Algorithm J

, , , , , streamj , , , , . . . ,

. .. .

. /

. , , , streama , , ,

, , ,

, , ,

, , , , ,

m V W Y n Z T P n n n

n n n n

z n n

m V W Y T P n Z

i i i i i i i i i i i nc

i i i i nc

i j i j i

i i i i i i i i

j n

=

⇐ + + +

⇐

⇐

( ) =

1 2

1 21

2

3

11 1 2for c

Beef, Inc. C-4 7/29/98




Simulation Algorithms

If the process state of a material stream is fully defined by knowing its temperature, pressure, total flow rate, and composition, then all of its unknown properties can be calculated, asdepicted in the HYSYS simulation algorithms below:

, , , streama , , ,

, , , streamb , , ,

, , , streamc , , ,

, , , streamd , , ,

, , , streame , , ,

, , , streamf , , ,

, , , streamg

m V W Y T P n Z

m V Y Z T P n W

m V W Z T P n Y

n V Y Z T P m W

n V W Y T P m Z

n V W Z T P m Y

m n W Z T

i i i i i i i i

i i i i i i i i

i i i i i i i i

i i i i i i i i

i i i i i i i i

i i i i i i i i

i i i i

=

=

=

=

=

=

= i i i i

i i i i i i i i

i i i i i i i i

P V Y

m n W Y T P V Z

m n Y Z T P V W

, , ,

, , , streamh , , ,

, , , streami , , ,

=

=

If the process state of a material stream is fully defined by knowing its temperature,

pressure, and component flow rates, then all of its unknown properties can be calculated, asdepicted in the HYSYS simulation algorithms below:

, , , , , streamj , , , , . . . ,

, , , , , streamk , , , , . . . ,

, , , , , streaml , , , , . . . ,

, , ,

, , ,

, , ,

n m V Z W Y T P n n n

n m V Z W Y T P m m m

n m V Z W Y T P V V V




=

=

=

1 2

1 2

1 2

If the process state of a material stream is multi-phase—either vapor-liquid or vapor-liquid-liquid; that is, two or more distinct phases coexist in equilibrium, then three additionalHYSYS simulation algorithms exist to determine the stream’s unknown properties as outlined inthe remaining pages of this appendix.

Beef, Inc. C-5 7/29/98




Vapor-Liquid Equilibrium

The above mathematical model for a process stream assumes its material is single phase—either all liquid or all vapor. At certain temperatures and pressures, the material in a process stream can be multi-phase—either vapor-liquid or vapor-liquid-liquid; that is, two ormore distinct phases can coexist in equilibrium. Our discussion here focuses on vapor-liquidequilibrium (vle).

HYSYS indicates multi-phases through the vapor fraction of a process stream. Vapor

fraction (V ) is the ratio of moles in the vapor phase over the total or bulk moles of the process

stream; that is, it is what fraction of the total exists in the vapor state. For example, a V = 0.4

implies that 40% of the total moles is vapor, while 60% is liquid. The vapor fraction’s range is:

f

f

0 1≤ ≤V f .

A calculated vapor fraction of zero indicates that the bulk material is all liquid. A calculatedvapor fraction of one implies that the bulk material is all vapor. A calculated value between zero

and one means a vapor and liquid are coexisting in equilibrium.

The vapor-liquid equilibrium for a multicomponent mixture is best illustrated by atemperature-versus-composition (TXY) diagram for a binary or 2-component system. A generalrepresentation of a TXY diagram is as follows:

cT bp

Vapor-Liquid

Region

yi,j

zi,j x

i,j

T dp

Saturated

Curve

Curve

SaturatedVa or

d

Liquid

T

a

L V

V f = 0

V f = 1

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 160

70

80

120

130

Pressure = Pi

Mole Fraction of Component j

T i

Liquid

Region

Vapor

Region

For process stream i at a specified pressure of Pi and bulk composition of Z i , a typical condition

of vapor-liquid equilibrium at temperature T i is represented by line segment LTV in the TXY

Beef, Inc. C-6 7/29/98




diagram. The end points of this line are called the saturated-liquid and saturated-vapor points,and they represent the compositions of the two phases in equilibrium: xi j, for the liquid phase,

for the vapor phase, and component j is the more volatile component in the binary system.

The vapor fraction for this equilibrium is given by line segment

yi j,

LTover LV , or in mathematicalterms, it is:

, , ,

, , ,

, ,

, ,

:

1.0 1.0

:

(1 )

:

i SV SL

SV SL f f

i i

i i j SV i j SL i j

i j f i j f i j

i j i j

f

i j i j

total balance n n n

n nV L

n n

component j balance n z n y n x for each j

z V y V x for each j

=

z xvapor fraction ratio V

y x

+

= + ⇒ = +

= +

= ⋅ + − ⋅

−=

−

d

The ratio for V f in terms of mole fractions is called the reverse-lever rule, because thecontribution of the vapor phase at Point V is given by the line segment on the opposite side ofPoint T. The V f equation is gotten by algebraically combining the total and component balances.

In the TXY diagram, the vertical Path a b depicts what would happen to

process stream i if it were cooled at the specified pressure and bulk composition. Point a indicates

that stream i would be in the vapor region, while Point d indicates the liquid region. Point b corresponds to a vapor fraction of one, and it is called the dew-point temperature

c→ → →

T dp . This point

is when the first drop of liquid would form while the vapor was cooled. Point c corresponds to avapor fraction of zero, and it is called the bubble-point temperature T bp . This point is when the

first bubble of vapor would form while the liquid was heated. When the following is true aboutthe temperature of process stream i:

T T T bp i dp≤ ≤ ,

you know that vapor-liquid equilibrium exist in process stream i.

In HYSYS, you can specify the vapor fraction instead of the temperature or pressure of a process stream. Three examples of vapor-liquid equilibrium (vle) calculations supported byHYSYS are:

T X Y V P Z

T X Y V P Z

T X Y V P Z

dp i i f i i

bp i i f i i

eq i i f i i

, , . , ,

, , . , ,, , . , ,

= =

= == =

vle

vlevle

1 0

0 00 6

where T eq is the equilibrium temperature of process stream i for the given vapor fraction. If you

were to specify T instead ofi Pi in the above three functional forms, you would be calculating the

dew-point pressure, bubble-point pressure, and equilibrium pressure, respectively, for processstream i.

Beef, Inc. C-7 7/29/98




When the material in process stream i is multi-phased, its bulk properties are related tothe saturated liquid and vapor properties through the reverse-lever rule, as was the case for the bulk composition above. Some common bulk molar properties for a vapor-liquid equilibrium(vle) system are given below.

ˆ ˆ ˆ ˆ ˆ ˆ(1 ) (1 )

ˆ ˆvmixSV , , hmixSV , ,

ˆ ˆvmixSL , , hmixSL , ,

i f SV f SL i f SV f S

SV i i i SV i i i

SL i i i SL i i i

V V V V V H V H V H

V T P Y H T P Y

V T P X H T P X

= ⋅ + − ⋅ = ⋅ + − ⋅

⎡ ⎤ ⎡ ⎤= =⎣ ⎦ ⎣ ⎦

⎡ ⎤ ⎡ ⎤= =⎣ ⎦ ⎣ ⎦

L

where T i is the temperature of process stream i, K.


V f is the molar vapor fraction of process stream i, / n nSV i .

L f is the molar liquid fraction of process stream i, . / n nSL i

ni is the bulk molar flow rate of process stream i, kgmol/h.

nSV is the molar flow rate of the saturated vapor in stream i, kgmol/h.n

SL is the molar flow rate of the saturated liquid in stream i, kgmol/h.



zi j, is the bulk mole fraction of component j in process stream i;

vector Z i means all elements z z zi i i n, , ,, , ,1 2 … c .

Y i is the sat’d vapor mole fractions of all nc-components in stream i.

yi j, is the sat’d vapor mole fraction of component j in process stream i;

vector Y i means all elements y y . y

i i i n, , ,, , ,

1 2 …

c

X i is the sat’d liquid mole fractions of all nc-components in stream i.

xi j, is the sat’d liquid mole fraction of component j in process stream i;

vector X i means all elements x x xi i i n, , ,, , ,1 2 … c .

iV is the bulk molar volume of process stream i, m3/kgmol.

SLV is the molar volume of the saturated vapor in stream i, m3/kgmol.

SV V is the molar volume of the saturated liquid in stream i, m3/kgmol.


H SV

is the molar enthalpy of the saturated vapor in stream i, kJ/kgmol. H SL is the molar enthalpy of the saturated liquid in stream i, kJ/kgmol.

The value of any bulk vle property must fall between the values for the saturated liquid and vapor

properties. If you expand the property view of a process stream, HYSYS will display its bulk,saturated liquid, and saturated vapor properties for the vapor-liquid equilibrium that exists in that process stream.

Beef, Inc. C-8 7/29/98



Appendix D. Mixer Module

Description

A mixer operation is used to combine two process streams to form one process materialstream. A pipe tee is used to accomplish the mixing operation. The two inlet streams to the pipetee are usually of the same phase, either liquid or vapor mixtures. The pressure of the exit stream

from the pipe tee is at the lowest pressure of the two inlet streams. If the inlet streams behave asideal mixtures (i.e., no heat of mixing effects), the exit temperature will lie between the two inlettemperatures. However, this temperature may be quite different than those of the inlet streamswhen mixing effects are significant. The conceptual diagram for the mixer operation is given below for a steady-state system. The system is the mixtures of chemical compounds (or

components) passing into, through, and from the pipe tee.

The mathematical model given below for the mixer operation balances the material andenergy flows of the system. This adiabatic unit operation occurs at steady state with no chemicalreaction, and the kinetic and potential energy changes are negligible. No shaft work exists withthis process operation. The independent set of equations contains the total and componentmaterial balances, the three sets of composition equations, the energy balance, the molar

enthalpies of the three process streams, and the pressure relationship for the exit stream. The exit pressure is set to the lowest pressure of the two inlet streams, in order to eliminate the potential of back flow to the inlet streams. To solve this set of equations, (2·nc+6) variables must bespecified, as indicated by the degrees-of-freedom analysis in the math model.

From this mathematical model, many mathematical algorithms can be derived for doing process simulation calculations. These algorithms differ in their given (or design) variables andtheir solution procedures. Two such algorithms are detailed below—knowing the process statesof two out of the three streams. The process state of a material stream is its temperature, pressure,total flow rate, and composition. The process state of the third stream is calculated using thesolution procedure defined in a math algorithm. Other possible simulation algorithms supported by the HYSYS software are summarized below.


inlet G

inlet F

Exit

T

P

n

Z

E

E

E

E

T

P

n

Z

G

G

G

G

T

P

n

Z

F

F

F

F

1. continuous process2. steady state3. no chemical reaction4. nelgect KE and PE changes5. adiabatic6. no shaft work

Beef, Inc. D-1 7/29/98




Mathematical Model

1

2

3

4

5

6

7

8

0

0

0

1 2

1 2

1 2

1 2

( )

=

=

=

=

+ − =

+ − =

= ⋅

= ⋅

= ⋅

⋅ + ⋅ − ⋅ =

=

( )

( )

( )

( )

( )

( )

( )

hmix , ,

, , ,

, ,

, ,

, ,

, , ,

, , ,

, , ,

, , ,

n n n

n n n

n n z

n n z

n n z

n H n H n H

H T P Z

H

F G E

F j G j E j

F j F F j

G j G G j

E j E E j

F F G G E E

F F F F

G

j n

j n

j n

j n

for

for

for

for

c

c

c

c

=

=

=

( )

( )

= ⋅

= ⋅

= ⋅

hmix , , hmix , ,

min ,

T P Z

H T P Z

P P P

G G G

E E E E

E F G

nc

9

10

12

4 6

6

# vars

# eqns

DOF

6 nc +

+

2 nc +


T i is the temperature of process stream i, K.P

i is the pressure of process stream i, kPa.


,ni j is the bulk molar flow rate of component j in process stream i, kgmol/h.



zi j,

is the bulk mole fraction of component j in process stream i;

vector Z i means all elements z z . zi i i n, , ,, , ,1 2 … c

H

i is the bulk molar enthalpy of process stream i, kJ/kgmol.

Ψi is a short notation for T P n Z i i i i of process stream i;, , , and

that is, the process state of stream i.

Beef, Inc. D-2 7/29/98





Ψ Ψ Ψ E F G

E F G

F j F j F

G j G j G

E j F j G j

E j E j E

F F F F

G G G

n n nn z n

n z n

n n n

z n n

H T P Z

H T P

j n

j n

j n

j n

=

⇐ +⇐ ⋅

⇐ ⋅

⇐ +

⇐

⇐

⇐

( )( ) =

( ) =

( ) =

( ) =

( )

( )

mixera ,

.

.

.

.

. /

. hmix , ,

. hmix , ,

, ,

, ,

, , ,

, ,

, , ,

, , ,

, , ,

, , ,

1

3

4

2

5

7

8

12

3

4

5

6

7

1 2

1 2

1 2

1 2

for

for

for

for

c

c

c

c

Z

H H n H n n

P P P

T

T H T P Z

T

G

E F F G G E

E F G

E

E E E E E

E

6

10

9

8

910

0

( )

( )

( )

⇐ ⋅ + ⋅

⇐

⇐ −

=

. /

. min ,

.

f hmix , ,

f

d i

b gb g

Iterate on in

until

Mathematical Algorithm B

Ψ Ψ ΨG E F

G E F

F j F j F

E j E j E

G j E j F j

G j G j G

F F F F

E E E

n n n

n z n

n z n

n n n

z n n

H T P Z

H T P

j n

j n

j n

j n

=

⇐ −

⇐ ⋅

⇐ ⋅

⇐ −

⇐

⇐

⇐

( )

( ) =

( ) =

( ) =

( ) =

( )

( )

mixerb ,

.

.

.

.

. /

. hmix , ,

. hmix , ,

, ,

, ,

, , ,

, ,

, , ,

, , ,

, , ,

, , ,

1

3

5

2

4

7

9

1

2

3

4

5

6

7

1 2

1 2

1 2

1 2

for

for

for

for

c

c

c

c

Z

H n H n H n

P P P

T

T H T P Z

T

E

G E E F F G

G E F

G

G G G G G

G

6

10

8

8

9

10

0

( )

( )

( )

⇐ ⋅ − ⋅

⇐

⇐ −

=

. /

. min ,

.

f hmix , ,

f

d i

b gb g

Iterate on in

until

Beef, Inc. D-3 7/29/98




HYSYS Simulation Algorithms

If the process states of any two streams are fully defined (i.e., the temperature, pressure,

flow rate, and composition of each stream are known), then the conditions of the third stream can be

calculated, as depicted in the HYSYS simulation algorithms below:

T P n Z T P n Z T P n Z



E E E E F F F F G G G G

G G G G F F F F E E E E

F F F F G G G G E E E E

, , , mixera , , , , , , ,

, , , mixerb , , , , , , ,

, , , mixerc , , , , , , ,

=

=

=

Many more algorithms can be used to solve the above mathematical model for a mixerunit operation. The degrees-of-freedom shows that (2·nc+6) variables must be specified to solvethe equations in the math model. Any combination of two temperatures, two pressures, two flowrates, and two compositions between the three process streams will solve the mixer module inHYSYS. Below are two examples.



E E G G F F F F G G E E

E G F F F F G G G E E E

, , , , , , , , , ,

, , , , , , , , , ,

=

=

mixerd

mixere

Beef, Inc. D-4 7/29/98



Appendix E. Pump Module

Description

A pump operation is used to increase the pressure of a liquid material stream that isflowing from one process unit to another in a process flowsheet. Power (energy/time) in the formof electric energy drives a motor coupled to a steel drive shaft. The drive shaft connected toimpellers imparts energy to the liquid in order to increase its pressure. The temperature of theliquid increases slightly, because of the effects of fluid friction. The conceptual diagram for the pump operation is given below for a steady-state system. The system is a liquid mixture ofchemical compounds (or components) passing into, through, and from the pump.

The mathematical model given below for the pump operation balances the material andenergy flows of the system. This adiabatic unit operation occurs at steady state with no chemicalreaction, and the kinetic and potential energy changes are negligible. The liquid is consideredincompressible (i.e., at constant density); a good assumption for any liquid well removed from itscritical point. The independent set of equations in the math model contains the total andcomponent material balances, the energy balance, the molar enthalpies of the two processstreams, the adiabatic efficiency, the ideal work based on the mechanical-energy balance for africtionless fluid, the pressure change, and the inlet mixture density and molecular weight. Theadiabatic efficiency relates the ideal to the actual work and has a typical value of 75% for mostliquids. To solve this set of equations, (nc+5) variables must be specified, as indicated by thedegrees-of-freedom analysis in the math model.

From this mathematical model, many mathematical algorithms can be derived for doing process simulation calculations. These algorithms differ in their given (or design) variables andtheir solution procedures. Two such math algorithms are detailed below—for knowing the process state of the inlet stream and two additional variables. The unknown variables arecalculated using the solution procedure defined in a math algorithm. The process state of amaterial stream is its temperature, pressure, total flow rate, and composition. Other possiblesimulation algorithms supported by the HYSYS software are summarized below.


Inlet

Exit

pump

T

P

n

Z

I

I

I

I

T

P

n

Z

E

E

E

E

W A

1.

continuous process2.

steady state3.

no chemical reaction4.

neglect KE and PE changes5.

adiabatic6.

incompressible liquid

Beef, Inc. E-1 7/29/98




Mathematical Model

1

2

3

4

5

6

7

8

9

10

14

0

0

0

100

1 2

( )

=

− =

⋅ − ⋅ =

⋅ − ⋅ + =

=

=

= ⋅

= ⋅ ⋅

= −

=

=

( )

( )

( )

( )

( )

( )

( )

( )

( )

= ⋅

hmix , ,

hmix , ,

/

/

liqden , ,

molwt

, , , , ,

n n

n z n z

n H n H W

H T P Z

H T P Z

W W

W P n M

P P P

T P Z

M Z

I E

I I j E E j

I I E E A

I I I I

E E E E

I A

I I I I

E I

I I I I

I I

j nfor

# vars

# eqns

ε

ρ

ρ

Δ

Δ

2 nc +

c

=

= ⋅

nc +

1 nc +

9

5DOF










W A is the actual work or power of the pump, kJ/h.ε is the adiabatic efficiency of the pump (0 to 100), percent.

W I is the ideal work or power of the pump (ε = 100%), kJ/h.

ΔP is the pressure drop between the exit and inlet streams, kPa. M

i is the molecular weight of process stream i, kg/kgmol.

ρ i is the liquid density of process stream i, kg/m3.

Beef, Inc. E-2 7/29/98





T P n Z W T P n Z P

n n

z z

P P P

T P Z

M Z

W P n M

W W

H T P Z

H n

E E E A I I I I E

E I

E j I j

E I

I I I I

I I

I I I I

A I

I I I I

E I

j n

, , , , pumpa , , , , ,

.

.

.

. liqden , ,

. molwt

. /

. /

. hmix , ,

.

, , , , ,

Δ

Δ

Δ

=

⇐

⇐

⇐ −

⇐

⇐

⇐ ⋅ ⋅

⇐ ⋅

⇐

⇐ ⋅

( )

( ) =

( )

( )

( )

( )

( )

( )

( )

ε

ρ

ρ

ε

1

2

8

9

10

7

6

4

3

1

2

3

4

5

6

7 100

8

9

1 2for c

/

.

f hmix , ,

f

H W n

T

T H T P Z

T

I A E

E

E E E E E

E

+

⇐ −

=

( )

d i

b g

b g

10

0

5

Iterate on in

until

Mathematical Algorithm E

Δ

Δ

P n Z W T P n Z T P

n n

z z

T P Z

M Z

H T P Z

H T P Z

W n H n H

P P P

W

E E A I I I I E E

E I

E j I j

I I I I

I I

I I I I

E E E E

A E E I I

E I

j n

, , , , pumpe , , , , ,

.

.

. liqden , ,

. molwt

. hmix , ,

. hmix , ,

.

.

.

, , , , ,

ε

ρ

=

⇐

⇐

⇐

⇐

⇐

⇐

⇐ ⋅ − ⋅

⇐ −

( )

( ) =

( )

( )

( )

( )

( )

( )

( )

1

2

9

10

4

5

3

8

7

1

2

3

4

5

6

7

8

9

1 2for

I I I I

I A

P n M

W W

⇐ ⋅ ⋅

⇐ ⋅( )

Δ /

. /

ρ

ε 6 10 100

c

Beef, Inc. E-3 7/29/98





If the process state of the inlet stream is fully defined (i.e., T P n Z I I I I , , , are known),

only two additional variables are required to calculate all unknowns, as depicited in the HYSYSsimulation algorithms below:

T P n Z W T P n Z P

T P n Z W T P n Z P

T P n Z P T P n Z W

P n Z W T P n Z T P

P n Z W T P n Z T P

T P

E E E A I I I I E

E E E E A I I I I

E E E E I I I I A

E E E A I I I I E

E E A I I I I E E

E E

, , , , pumpa , , , , ,

, , , , pumpb , , , , ,

, , , , pumpc , , , , ,

, , , , pumpd , , , , ,

, , , , pumpe , , , , ,

,

Δ

Δ

Δ

Δ

Δ

=

=

=

=

=

ε

ε

ε

ε

ε

, , , pumpf , , , , ,

, , , , pumpg , , , , ,

n Z T P n Z W P

T P n Z T P n Z W P

E E I I I I A

E E E I I I I A E

ε

ε

=

=

Δ

Δ

If the process state of the exit stream is fully defined (i.e., T P n Z E E E E , , , are known),

only two additional variables are required to calculate all unknowns, as depicited in the HYSYS

simulation algorithms below:

T P n Z W T P n Z P

T P n Z W T P n Z P

T P n Z P T P n Z W

P n Z W T P n Z T P

P n Z W T P n Z T P

T P

I I I I A E E E E

I I I A E E E E I

I I I I E E E E A

I I I A E E E E I

I I A E E E E I I

I I

, , , , pumph , , , , ,

, , , , pumpi , , , , ,

, , , , pumpj , , , , ,

, , , , pumpk , , , , ,

, , , , pumpl , , , , ,

,

=

=

=

=

=

ε

ε

ε

ε

ε

Δ

Δ

Δ

Δ

Δ

, , , pumpm , , , , ,

, , , , pumpn , , , , ,

n Z T P n Z W P

T P n Z T P n Z W P

I I E E E E A

I I I E E E E A I

ε

ε

=

=

Δ

Δ

Beef, Inc. E-4 7/29/98



Appendix F. Valve Module

Description

A valve operation is used to decrease the pressure of a process material stream. The process simulation of a valve can determine the process state of the exit stream given the processstate of the inlet stream or determine the process state of the inlet stream given the process state

of the exit stream. The process state of a material stream is its temperature, pressure, total flowrate, and composition. The conceptual diagram for the valve operation is given below for asteady-state system. The system is the mixture of chemical compounds (or components) passinginto, through, and from the valve.

The mathematical model given below for the valve operation balances the material andenergy flows of the system. This adiabatic unit operation occurs at steady state with no chemicalreaction, and the kinetic and potential energy changes are negligible. The independent set ofequations in the math model contains the total and component material balances, the energy balance, the molar enthalpies of the two process streams, and the definition of pressure drop. Tosolve these equations, (nc+4) variables must be specified, as indicated by the degrees-of-freedomanalysis in the math model.

From this mathematical model, many mathematical algorithms can be derived for doing process simulation calculations. These algorithms differ in their given (or design) variables andtheir solution procedures. Two such math algorithms are shown below—one for the process stateof the inlet stream given, and the other for the exit stream given. The unknown variables arecalculated using the solution procedure defined in a math algorithm. Again, the process state of amaterial stream is its temperature, pressure, total flow rate, and composition. Other possiblesimulation algorithms supported by the HYSYS software are summarized below.


valveInlet Exit

T

P

n

Z

I

I

I

I

T

P

n

Z

E

E

E

E

1.

continuous process2.

steady state

3. no chemical reaction4. neglect KE and PE changes5. adiabatic6. no shaft work

Beef, Inc. F-1 7/29/98




Mathematical Model

1

2

3

4

5

6

9

5

4

0

0

0

1 2

( )

=

− =

⋅ − ⋅ =

⋅ − ⋅ =

=

=

= −

( )

( )

( )

( )

( )

= ⋅

=

= ⋅

hmix , ,

hmix , ,

, , , , ,

n n

n z n z

n H n H

H T P Z

H T P Z

P P P

I E

I I j E E j

I I E E

I I I I

E E E E

I E

j n

nc

for

# vars

# eqns

DOF

Δ

2 nc +

+

1 nc +

c





nc is the number of chemical components or compounds in the mixture. Z

i is the bulk mole fractions of all nc-components in stream i.



H

i is the bulk molar enthalpy of process stream i, kJ/kgmol.

ΔP is the pressure drop between the exit and inlet streams, kPa.



Beef, Inc. F-2 7/29/98





Ψ Ψ Δ

Δ

E I

E I

E j I j

E I

I I I I

E I

E

E E E E E

E

P

n n

z z

P P P

H T P Z

H H

T

T H T P Z

T

j n

=

⇐

⇐

⇐ −

⇐

⇐

⇐ −

=

( )

( ) =

( )

( )

( )

( )

valvea ,

.

.

.

. hmix , ,

.

.

f hmix , ,

f

, , , , ,

1

2

6

4

3

5

1

2

3

4

5

6

0

1 2for

Iterate on in

until

b g

b g

c


Ψ Ψ Δ

Δ

I E

I E

I j E j

I E

E E E E

I E

I

I I I I I

I

P

n n

z z

P P P

H T P Z

H H

T

T H T P Z

T

j n

=

⇐

⇐

⇐ +

⇐

⇐

⇐ −

=

( )

( ) =

( )

( )

( )

( )

valved ,

.

.

.

. hmix , ,

.

.

f hmix , ,

f

, , , , ,

1

2

6

5

3

4

1

2

3

4

5

6

0

1 2for

Iterate on in

until

b g

b g

c

Beef, Inc. F-3 7/29/98





If the process state of the inlet stream is fully defined (i.e., the temperature, pressure, flow

rate and composition are known), only one additional variable is required to calculate all unknowns,as depicted in the HYSYS simulation algorithms below:

T P n Z T P n Z P

T P n Z T P n Z P

P n Z P T P n Z T

E E E E I I I I

E E E I I I I E

E E E I I I I E

, , , valvea , , , ,

, , , valveb , , , ,

, , , valvec , , , ,

=

=

=

Δ

Δ

Δ

If the process state of the exit stream is fully defined (i.e., the temperature, pressure, flowrate and composition are known), only one additional variable is required to calculate all unknowns,as depicted in the HYSYS simulation algorithms below:

T P n Z T P n Z P

T P n Z T P n Z P

P n Z P T P n Z T

I I I I E E E E

I I I E E E E I

I I I E E E E I

, , , , , , ,

, , , , , , ,

, , , , , , ,

=

=

=

valved

valvee

valvef

Δ

Δ

Δ

Beef, Inc. F-4 7/29/98



Appendix G. Heater/Cooler Module

Description

A heater or cooler operation is used to increase or decrease the energy content of a process material stream. A heater adds energy to the material in a process stream to increase itstemperature. A cooler takes away energy from the material in a process stream to decrease its

temperature. Neither unit operation affects the stream bulk and component flow rates orcomposition. The energy added or subtracted from the stream by a heater or cooler, respectively,is known as the duty of that unit operation. A cooler is essentially a heater with a negative dutyvalue, and vice versa. The conceptual diagram for the heater/cooler operation is given below fora steady-state system. The system is the mixture of chemical compounds (or components) passinginto, through, and from the heater or cooler.

The mathematical model given below for the heating operation balances the material andenergy flows of the system. This model also represents the cooling of a process stream if the dutyis a negative number. The unit operation occurs at steady state with no chemical reaction, and thekinetic and potential energy changes are negligible. The independent set of equations in the mathmodel contains the total and component material balances, the energy balance, the molar

enthalpies of two process streams, and the definition of pressure drop. To solve these equations,(nc+5) variables must be specified, as indicated by the degrees-of-freedom analysis in the mathmodel.

From this mathematical model, many mathematical algorithms can be derived for doing process simulation calculations. These algorithms differ in their given (or design) variables andtheir solution procedures. Two such math algorithms are shown below—one for the process stateof the inlet stream and exit temperature and pressure given, and one for the process state of theinlet stream, duty and exit pressure given. The unknown variables are calculated using thesolution procedure defined in a math algorithm. The process state of a material stream is itstemperature, pressure, total flow rate, and composition. Other possible simulation algorithmssupported by the HYSYS software are summarized below.


heater

QT

P

n

Z

I

I

I

I

Inlet Exit

T

P

n

Z

E

E

E

E

1. continuous process2. steady state3.

no chemical reaction4.

neglect KE and PE changes

5. no shaft work

Beef, Inc. G-1 7/29/98




Mathematical Model

1

2

3

4

5

6

10

5

5

0

0

0

1 2

( )

=

− =

⋅ − ⋅ =

⋅ − ⋅ + =

=

=

= −

( )

( )

( )

( )

( )

= ⋅

=

= ⋅

hmix , ,

hmix , ,

, , , , ,

n n

n z n z

n H n H Q

H T P Z

H T P Z

P P P

I E

I I j E E j

I I E E

I I I I

E E E E

E I

j n

nc

for

# vars

# eqns

DOF

Δ

2 nc +

+

1 nc +

c








vector Z i means all elements z z . z

i i i n, , ,, , ,1 2 … c

Q is the energy duty of the heater or cooler, kJ/h.



Ψi is a short notation for T P n Z i i i i of process stream i;, , , andthat is, the process state of stream i.

Beef, Inc. G-2 7/29/98





Δ Ψ

Δ

P n Z Q T P

n n

z z

P P P

H T P Z

H T P Z

Q n H n H

E E I E E

E I

E j I j

E I

I I I I

E E E E

E E I I

j n

, , , heatera , ,

.

.

.

. hmix , ,

. hmix , ,

.

, , , , ,

=

⇐

⇐

⇐ −

⇐

⇐

⇐ ⋅ − ⋅

( )

( ) =

( )

( )

( )

( )

1

2

6

4

5

3

1

2

3

4

5

6

1 2for c


T P n Z P Q

n n

z z

P P P

H T P Z

H n H Q n

T

T H T P Z

T

E E E I E

E I

E j I j

E I

I I I I

E I I E

E

E E E E E

E

j n

, , , heatere , ,

.

.

.

. hmix , ,

. /

.

f hmix , ,

f

, , , , ,

Δ Ψ

Δ

=

⇐

⇐

⇐ −

⇐

⇐ ⋅ +

⇐ −

=

( )

( ) =

( )

( )

( )

( )

1

2

6

4

3

5

1

2

3

4

5

6

0

1 2for

Iterate on in

until

d i

b g

b g

c

Beef, Inc. G-3 7/29/98





If the process state of the inlet stream is fully defined (i.e., the temperature, pressure, flow

rate and composition are known), only two additional variable are required to calculate allunknowns, as depicted in the HYSYS simulation algorithms below:

Δ

Δ

Δ

Δ

Δ

P n Z Q T P n Z T P

T P n Z T P n Z P Q

P n Z Q T P n Z P T

P n Z P T P n Z Q T

T n Z P T P n Z Q P

E E I I I I E E

E E E E I I I I

E E E I I I I E

E E E I I I I E

E E E I I I I E

, , , heatera , , , , ,

, , , heaterb , , , , ,

, , , heaterc , , , , ,

, , , heaterd , , , , ,

, , , heatere , , , , ,

=

=

=

=

=

If the process state of the exit stream is fully defined (i.e., the temperature, pressure, flow

rate and composition are known), only two additional variable are required to calculate allunknowns, as depicted in the HYSYS simulation algorithms below:

Δ

Δ

Δ

Δ

Δ

P n Z Q T P n Z T P

T P n Z T P n Z P Q

P n Z Q T P n Z P T

P n Z P T P n Z Q T

T n Z P T P n Z Q P

I I E E E E I I

I I I I E E E E

I I I E E E E I

I I I E E E E I

I I I E E E E I

, , , heaterf , , , , ,

, , , heaterg , , , , ,

, , , heaterh , , , , ,

, , , heateri , , , , ,

, , , heaterj , , , , ,

=

=

=

=

=

Beef, Inc. G-4 7/29/98



Appendix H. Chemical Reactor Module

Description

HYSYS supports the process simulation of many different types of chemical reactors.

Our focus here is on the conversion-based model for a reactor. A chemical reactor operationtakes the reactants of a feed stream and converts them, usually in the presence of a catalyst, to the

desired product, which appears in the effluent stream. Because most reactions do not go tocompletion, the effluent stream will usually contain some reactants and inert materials from thefeed stream as well as by-products and waste materials. The conceptual diagram for the reactoroperation is given below for a steady-state system. The system is the mixture of chemicalcompounds (or components) passing into, through, and from the reactor.

The mathematical model given below for the reactor operation balances the material andenergy flows of the system. It is illustrated for a specific reaction stoichoimetry —the productionof styrene monomer from toluene and methanol with the by-product formation of ethylbenzene.This adiabatic unit operation occurs at steady state with no shaft work, and the kinetic and potential energy changes are negligible. The independent set of equations in the math modelcontains the total and component material balances, the two sets of composition equations, the

reaction conversion and yield equations, the energy balance, the molar enthalpies of the two process streams, and the definition of pressure drop. To solve these equations, (nc+6) variablesmust be specified, as indicated by the degrees-of-freedom analysis in the math model.

From this mathematical model, many mathematical algorithms can be derived for doing process simulation calculations. These algorithms differ in their given (or design) variables andtheir solution procedures. One such algorithm is shown below with the process state of the feedmaterial stream, reaction conversion and yield, and pressure drop as the specified variables. The process state of a material stream is its temperature, pressure, total flow rate, and composition.Other possible simulation algorithms supported by the HYSYS software are summarized below.


T

P

n

Z

E

E

E

E

T

P

n

Z

F

F

F

F

Reactor

Feed Effluent

1. continuous process2. steady state3. neglect KE and PE changes4. adiabatic5. no shaft work

Chemical Reaction Stoichoimetry

Rxn 1: C7H8 + CH3OH ↔ C8H8 + H2O + H2

toluene methanol styrene water hydrogen

(TL) (ME) (SM) (WA) (H2)

Rxn 2: C7H8 + CH3OH ↔ C8H10 + H2O

toluene methanol ethylbenzene water

(TL) (ME) (EB) (WA)

Beef, Inc. H-1 7/29/98




Mathematical Model

( )

( )

( )

( )

( )

( )

( )

( )

( )

( )

1 1

2 , , 1 2

3 , , 1 2

4 , , 1

5 , , 2

6 , , 1 2

7 , 2 , 2 1

8 , ,

9 , ,

10

for 1, 2, ,

for 1, 2, ,

0

0

0

0

0

0

0

F E

F TL E TL

F ME E ME

F SM E SM

F EB E EB

F WA E WA

F H E H

F j F F j

E j E E j

j nc

j nc

n n R

n n R R

n n R R

n n R

n n R

n n R R

n n R

n n Z

n n Z

=

=

− + =

− − − =

− − − =

− + =

− + =

− + + =

− + =

= ⋅= ⋅

( )( ) ( )

( )

( )

( )

( )

, , ,

11 , , ,

12

13

14

15

# vars 4 13

# eqns 3 7

DOF 1 6

/

/

ˆ ˆ 0

ˆ hmix , ,ˆ hmix , ,

TL F TL E TL F TL

SM E SM F TL E TL

F F E E

F F F F

E E E E

F E

nc

nc

nc

n n n

Y n n n

n H n H

H T P Z

H T P Z

P P P

ε

= ⋅ +

= ⋅ +

= ⋅ +

= −

= −

⋅ − ⋅ =

⎡ ⎤= ⎣ ⎦⎡ ⎤= ⎣ ⎦

Δ = −





,ni j


Beef, Inc. H-2 7/29/98







vector Z i means all elements z z . z

i i i n, , ,, , ,1 2 … c

R1 is the extent of the styrene monomer reaction (i.e., Rxn 1), 1/h. R2 is the extent of the ethylbenzene reaction (i.e., Rxn 2), 1/h.ε TL is the molar conversion of toluene (moles of toluene reacted per moles of toluene fed).Y SM is the molar yield of styrene (moles of styrene formed per moles of toluene reacted).






Ψ Ψ Δ E F TL SM

F j F F j

E TL F TL E TL TL

E SM SM F TL E TL

E SM F SM

E EB F EB

E F

E TL F TL

E

Y P

n n x

n n n

n Y n n

R n n

R n n

n R n

n n R R

n

j n

=

⇐ ⋅

⇐ − ⋅

⇐ −

⇐ −

⇐ −

⇐ +

⇐ − −

( ) =

( )

( )

( )

( )

( )

( )

( )

reactora

for

, , ,

.

.

.

.

.

.

.

.

, ,

, , ,

, , ,

, ,

, ,

, ,

,

, , ,

ε

ε

8

10

11

4

5

1

2

3

1

2

3

4

5

6

7

8

1 2

1

2

1

1 2

c h

c

ME F ME

E H F H

E WA F WA

E j E j E

E F

F F F F

E F F E

E

E E E E E

E

n R R

n n R

n n R R

z n n

P P P

H T P Z

H n H n

T

T H T P Z

T

j n

⇐ − −

⇐ +

⇐ + +

⇐

⇐ −

⇐

⇐ ⋅

⇐ −

=

( )

( )

( ) =

( )

( )

( )

( )

.

.

. /

.

. hmix , ,

. /

.

f hmix , ,

f

,

, ,

, ,

, , , , ,

1 2

2 2 1

1 2

7

6

9

15

13

12

14

9

10

11

12

13

14

15

0

1 2for

Iterate on in

until

Δ

b g

b g

c

Beef, Inc. H-3 7/29/98





If the process state of the feed stream is fully defined (i.e., the temperature, pressure, flow

rate and composition are known), only three additional variables plus the reaction stoichoimetriesare required to calculate all unknowns, as depicted in the HYSYS simulation algorithms below:

T P n Z T P n Z Y P

T P n Z T P n Z Y P

E E E E F F F F TL SM

E E E F F F F TL SM E

, , , reactora , , , , , ,

, , , , , , , , ,

=

=

ε

ε

Δ

Δ reactorb

HYSYS can not do back calculations for the conversion reactor. Therefore, the only variation onthe simulation algorithms that works in HYSYS is specifying either the effluent pressure or the pressure drop.

In HYSYS, the stoichoimetry of each reaction and its associated molar conversion arespecified in a reaction set of the Fluid Package. You must define a reaction set for each chemicalreaction that occurs in the reactor.

Beef, Inc. H-4 7/29/98



Appendix I. Two-Phase Separator Module

Description

A two-phase separator operation is used to separate a feed process stream into twomaterial streams according to phase. A vapor-liquid equilibrium is reached in the vessel at acertain temperature and pressure. When the feed pressure is higher than the vessel pressure, a

flash operation occurs in the vessel producing the two phases; otherwise, withdrawing heat fromthe feed stream produces the two phases. The two phases are then separated into a saturatedvapor stream and a saturated liquid stream. The conceptual diagram for the two-phase separationoperation is given below for a steady-state system. The system is the mixture of chemicalcompounds (or components) passing into, through, and from the two-phase separator.

The mathematical model given below for the two-phase separation balances the materialand energy flows of the system. This unit operation occurs at steady state with no chemicalreaction and shaft work, and the kinetic and potential energy changes are negligible. Theindependent set of equations contains the total material and energy balances, the vapor-liquidequilibrium function (vle), the relationships between vapor fraction and flow rates, therelationships between the outlet temperatures and pressures, the molar enthalpies of the three

process streams, and the definition of pressure change. To solve these equations, (nc+5) variablesmust be specified, as indicated by the degrees-of-freedom analysis in the math model.

From this mathematical model, many mathematical algorithms can be derived for doing process simulation calculations. These algorithms differ in their given (or design) variables andtheir solution procedures. One such algorithm is shown below for the process state of the feedstream given. The unknown variables are calculated using the solution procedure defined in amath algorithm. The process state of a material stream is its temperature, pressure, total flow rate,and composition. Other possible simulation algorithms supported by the HYSYS software aresummarized below.


Q

T

P

n

Z

F

F

F

F

sat’d liquid

sat’d vapor

Vapor

Feed

Liquid

T

P

n

Z

V

V

V

V

T

P

n

Z

L

L

L

L

1. continuous process2. steady state3. no chemical reaction4. neglect KE and PE changes5. no shaft work

Beef, Inc. I-1 7/29/98




Mathematical Model

1

2

3

4

5

6

7

8

9

10

17

2 12

5

0

0

( ) − − =

⋅ − ⋅ − ⋅ + =

=

=

=

=

=

=

=

= −

( )

( )

( )

( )

( )

( )

( )

( )

( )

= ⋅

= ⋅

= ⋅

, , vle , ,

/

hmix , ,

hmix , ,

hmix , ,

n n n

n H n H n H Q

V Y X T P Z

V n n

T T

P P

H T P Z

H T P Y

H T P X

P P P

F V L

F F V V L L

f V L V V F

f V F

L V

L V

F F F F

V V V V

L L L L

F V

nc

Δ

# vars

# eqns

DOF

3 nc +

+

1 nc +


T i is the temperature of process stream i, K.Pi is the pressure of process stream i, kPa.n

i is the molar flow rate of process stream i, kgmol/h.





Y i is the vapor mole fractions of all nc-components in stream i.

X i is the liquid mole fractions of all nc-components in stream i.

V f is the molar vapor fraction of the vapor-liquid equilibrium.Q is the energy duty of the two-phase separator, kJ/h.

H i is the molar enthalpy of process stream i, kJ/kgmol.


Ψi is a short notation for T P ni i i, , , and composition of process stream i;


Beef, Inc. I-2 7/29/98





P n Y Q P T

P P P

V Y X T P Z

n V n

n n n

T T

P P

H T P Z

H T P Y

H T P X

Q n H

V V V L F V

V F

f V L V V F

V f F

L F V

L V

L V

F F F F

V V V V

L L L L

V

, , , , sepa , ,

.

. , , vle , ,

.

.

.

.

. hmix , ,

. hmix , ,

. hmix , ,

.

Ψ Ψ Δ

Δ

=

⇐ −

⇐

⇐ ⋅

⇐ −

⇐

⇐

⇐

⇐

⇐

⇐ ⋅

( )

( )

( )

( )

( )

( )

( )

( )

( )

( )

10

3

4

1

5

6

7

8

9

2

1

2

3

4

5

6

7

8

9

10 V L L F F n H n H + ⋅ − ⋅



rate and composition are known), only two additional variables are required to calculate allunknowns, as depicted in the HYSYS simulation algorithms below:

P n Y Q P T

P n Y Q P T

T P n Y P Q

T n Y P P Q

V V V L F V

V V L F V V

V V V V L F

V V V L F V

, , , , sepa , ,

, , , , sepb , ,

, , , , sepc , ,

, , , , sepd , ,

Ψ Ψ

Δ Ψ Ψ

Ψ Ψ Δ

Ψ Δ Ψ

=

=

=

=

Δ

HYSYS can also back calculate for the feed stream conditions given certain information about theexit streams and the unit operation. Because of the nature of the vapor-liquid equilibrium, back-calculation requires one more given variable than the forward calculation. So to back-calculate,(nc+6) variables must be specified. These variables are two of the three total flow rates, one exitcomposition, one exit temperature or pressure, the pressure drop, and the duty of the two-phaseseparator.

Beef, Inc. I-3 7/29/98



Appendix J. Three-Phase Separator Module

Description

A three-phase separator operation is used to separate a feed process stream into threematerial streams according to phase. A vapor-liquid-liquid equilibrium is reached in the vessel ata certain temperature and pressure. When the feed pressure is higher than the vessel pressure, a

flash operation occurs in the vessel producing the three phases; otherwise, withdrawing heat fromthe feed stream produces the three phases. The three phases are then separated into a vaporstream, a light-liquid (organic) stream and a heavy-liquid (aqueous) stream. The conceptualdiagram for the three-phase separation operation is given below for a steady-state system. Thesystem is the mixture of chemical compounds (or components) passing into, through, and from thethree-phase separator.

The mathematical model given below for the three-phase separation balances the materialand energy flows of the system. This unit operation occurs at steady state with no chemicalreaction and shaft work, and the kinetic and potential energy changes are negligible. Theindependent set of equations contains the total material and energy balances, the vapor-liquid-liquid equilibrium function (vlle), the relationships between phase fractions and flow rates, the

relationships between the outlet temperatures and pressures, the molar enthalpies of the four process streams, and the definition of pressure change. To solve these equations, (nc+5) variablesmust be specified, as indicated by the degrees-of-freedom analysis in the math model.

From this mathematical model, many mathematical algorithms can be derived for doing process simulation calculations. These algorithms differ in their given (or design) variables andtheir solution procedures. One such algorithm is shown below for the process state of the feedstream given. The unknown variables are calculated using the solution procedure defined in amath algorithm. The process state of a material stream is its temperature, pressure, total flow rate,and composition. Other possible simulation algorithms supported by the HYSYS software aresummarized below.


T

P

n

Z

L

L

L

L

T

P

n

Z

V

V

V

V

aqueous

organic

vapor

Light

Heavy

Feed

Q

Vapor

T

P

n

Z

F

F

F

F

T

P

n

Z

H

H

H

H


Beef, Inc. J-1 7/29/98




Mathematical Model

1

2

3

4

5

6

7

8

9

10

0

0

( ) − − − =

⋅ − ⋅ − ⋅ − ⋅ + =

=

=

=

= =

= =

=

=

=

( )

( )

( )

( )

( )

( )

( )

( )

( )

, , , , vlle , ,

/

/

hmix , ,

hmix , ,

hmix , ,

n n n n

n H n H n H n H Q

V L Y X X T P Z

V n n

L n n

T T T

P P P

H T P Z

H T P Y

H T P

F V L H

F F V V L L H H

f fL V L H V V F

f V F

fL L F

L H V

L H V

F F F F

V V V V

L L L X

H T P X

P P P

L

H H H H

F V

nc

11

12

22

3 17

5

( )

( )

= ⋅

= ⋅

= ⋅

=

= −

hmix , ,

Δ

# vars

# eqns

DOF

4 nc +

+

1 nc +



Pi is the pressure of process stream i, kPa.ni is the molar flow rate of process stream i, kgmol/h.





Y i is the vapor mole fractions of all nc-components in stream i.

X i is the liquid mole fractions of all nc-components in stream i.

V f is the molar vapor fraction of the vapor-liquid-liquid (vll) equilibrium.

L fL is the molar light-liquid fraction of the vll equilibrium.Q is the energy duty of the two-phase separator, kJ/h.

H i is the molar enthalpy of process stream i, kJ/kgmol.




Beef, Inc. J-2 7/29/98





P n Y Q P T

P P P

V L Y X X T P Z

n n V

n n L

n n n n

T T T

P P P

H T P Z

H T P

V V V L H F V

V F

f fL V L H V V F

V F f

L F fL

H F V L

L H V

L H V

F F F F

V V V

, , , , , sepa , ,

.

. , , , , vlle , ,

.

.

.

. ,

. ,

. hmix , ,

. hmix , ,

Ψ Ψ Ψ Δ

Δ

=

⇐ −

⇐

⇐ ⋅

⇐ ⋅

⇐ − −

⇐

⇐

⇐

⇐

( )

( )

( )

( )

( )

( )

( )

( )

( )

12

3

4

5

1

6

7

8

9

1

2

3

4

5

6

7

8

9 Y

H T P X

H T P X

Q n H n H n H n H

V

L L L L

H H H H

V V L L H H F F

10

11

2

10

11

12

( )

( )

( )

⇐

⇐

⇐ ⋅ + ⋅ + ⋅ − ⋅

. hmix , ,

. hmix , ,

.


If the process state of the feed stream is fully defined (i.e., the temperature, pressure, flowrate and composition are known), only two additional variables are required to calculate allunknowns, as depicted in the HYSYS simulation algorithms below:

P n Y Q P T

P n Y Q P T

T P n Y P Q

T n Y P P Q

V V V L H F V

V V L H F V V

V V V V L H F

V V V L H F V

, , , , , sepa , ,

, , , , , sepb , ,

, , , , , sepc , ,

, , , , , sepd , ,

Ψ Ψ Ψ Δ

Δ Ψ Ψ Ψ

Ψ Ψ Ψ Δ

Ψ Ψ Δ Ψ

=

=

=

=

HYSYS can also back calculate for the feed stream conditions given certain information about theexit streams and the unit operation. Because of the nature of the vapor-liquid-liquid equilibrium, back-calculation requires one more given variable than the forward calculation. So to back-calculate, (nc+6) variables must be specified. These variables are three of the four total flowrates, one exit composition, one exit temperature or pressure, the pressure drop, and the duty ofthe three-phase separator.

Beef, Inc. J-3 7/29/98



Appendix K. Component Splitter Module

Description

A component splitter operation is used to approximate the separation of a material feed

stream into a product and bottoms streams; that is, it is the simplest model that one can use for aseparation operation. The component splitter solves for the process state of the two exit streams

given the process state of the feed stream and the fractional split of each feed component thatgoes into the product stream. The process state of a material stream is its temperature, pressure,total flow rate, and composition. The conceptual diagram for the component splitter operation isgiven below for a steady-state system. The system is the mixture of chemical compounds (or

components) passing into, through, and from the component splitter.

The mathematical model given below for the component splitter operation balances thematerial and energy flows of the system. This unit operation occurs at steady state with nochemical reaction, and the kinetic and potential energy changes are negligible. The independentset of equations in the math model contains the total and component material balances, thecomponent composition equations, the product mixture equation, the component fractional splits,the energy balance, the molar enthalpies of the three process streams, and the vapor fractions of

the two exit streams. To solve these equations, (2nc+7) variables must be specified, as indicated by the degrees-of-freedom analysis in the math model.

From this mathematical model, many mathematical algorithms can be derived for doing process simulation calculations. These algorithms differ in their given (or design) variables and

their solution procedures. One such math algorithm is shown below— where the process stateof the feed stream, the overhead split fractions, and the temperature and pressure of thetwo exit streams are given. The unknown variables are calculated using the solution procedure

defined in a math algorithm. Again, the process state of a material stream is its temperature, pressure, total flow rate, and composition. Other possible simulation algorithms supported by theHYSYS software are summarized below.


T

P

n

X

P

P

P

P

T

P

n

X

B

B

B

B

componentsplitter

Q

T

P

n

Z

F

F

F

F

Feed

Bottoms

Product


Beef, Inc. K-1 7/29/98




Mathematical Model

1

2

3

4

5

6

7

8

0

0 1 2

1 2

1 2

1 2

1 2

1

( )

=

=

=

=

=

− − =

− − =

= ⋅= ⋅

= ⋅

=

=

( )

( )

( )

( )

( )

( )

( )

=

∑

/

, , ,

, ,

, ,

, ,

,

, ,

, , ,

, , ,

, , ,

, , ,

, , ,

n n n

n n n

n n zn n x

n n x

n n

f n n

n

F P B

F j P j B j

F j F F j

P j P P j

B j B B j

P P j

j

nc

j P j F j

F

j n

j n

j n

j n

j n

for

for

for

for

for

c

c

c

c

c

⋅ − ⋅ − ⋅ + =

=

=

=

=

=

( )

( )

( )

( )

( )

= ⋅

= ⋅

= ⋅

hmix , ,

hmix , ,

hmix , ,

vfrac , ,

vfrac , ,

,

,

H n H n H Q

H T P Z

H T P X

H T P X

V T P X

V T P X

F P P B B

F F F F

P P P P

B B B B

f P P P P

f B B B B

nc

0

9

10

11

12

13

15

5 8

7

# vars

# eqns

DOF

7 nc +

+

2 nc +


T i is the temperature of process stream i, K.Pi

is the pressure of process stream i, kPa.ni is the bulk molar flow rate of process stream i, kgmol/h.

,ni j is the bulk molar flow rate of component j in process stream i, kgmol/h.

nc is the number of chemical components or compounds in the mixture. zi j, is the bulk mole fraction of component j in process stream i;

vector Z i means all elements z z for stream i. zi i i n, , ,, , ,1 2 … c

xi j, is the liquid mole fraction of component j in process stream i;

vector X i means all elements x x xi i i n, , ,, , ,1 2 … c for stream i.

f j is the fraction of component j in the feed that goes to the product stream;

vector f means all elements f f f nc1 2, , ,… for the nc-components.

H i is the molar enthalpy of process stream i, kJ/kgmol.Q is the energy duty of the component splitter, kJ/h.

V f i, is the molar vapor fraction of the phase equilibrium in process stream i.



Beef, Inc. K-2 7/29/98





, , , , splittera , , , , ,

.

.

.

.

.

. /

, ,

, ,

, , ,

,

, ,

, , ,

, , ,

, , ,

n X n X Q f T P T P

n n z

n f n

n n n

n n

n n n

x n n

P P B B F P P B B

F j F F j

P j j F j

B j F j P j

P P j

j

nc

B F P

P j P j P

j n

j n

j n

=

⇐ ⋅

⇐ ⋅

⇐ −

⇐

⇐ −

⇐

( ) =

( ) =

( ) =

( )

( )

( )

=

∑

Ψ

3

7

2

6

1

4

1

2

3

4

5

6

1 2

1 2

1 2

1

for

for

for

c

c

c

for

for

j n

j n x n n

H T P Z

H T P X

H T P X

Q n H n H n H

V T P X

V T P X

B j B j B

F F F F

P P P P

B B B B

P P B B F F

f P P P P

f B B B B

=

( ) =

( )

( )

( )

( )

( )

( )

⇐

⇐

⇐

⇐

⇐ ⋅ + ⋅ − ⋅

⇐

⇐

1 2

1 25

9

10

11

8

12

13

7

8

9

10

11

12

13

, , ,

, , ,. /

. hmix , ,

. hmix , ,

. hmix , ,

.

. vfrac , ,

. vfrac , ,

, ,

,

,

c

c



rate and composition are known) and the component fractional splits are given, only four additionalvariables are required to calculate all unknowns, as depicted in the HYSYS simulation algorithms below:

, , , , , , splittera , , , , ,

, , , , , , , , , , ,

, , , , , , , , , , ,

, , , , , , , , , , ,

, ,

, ,

, ,

, ,

n X n X V V Q f T P T P

n X n X T T Q f P V P V

n X n X P P Q f T V T V

n X n X T V V f Q P T P

P P B B f P f B F P P B B

P P B B P B F P f P B f B

P P B B P B F P f P B f B

P P B B P f P f B F P B B

=

=

=

=

Ψ

Ψ

Ψ

Ψ

splitterb

splitterc

splitterd

These are but a few of the many simulation algorithms for this unit operation. You can select thefour additional variables for among the exit temperatures, exit pressures, exit vapor fractions, and

the heat duty. HYSYS can not do back calculations on the component splitter. Thus, you mustalways specify the process state of the feed stream.

Beef, Inc. K-3 7/29/98



Appendix L. Simple Distillation Module

Description

A simple distillation operation is used to separate a feed process stream into two productstreams—the distillate and bottoms materials. As illustrated in the conceptual diagram below, adistillation column is composed of several process units—a condenser, a finite number of

equilibrium stages (one of which is the feed stage), and a reboiler. A distillation column exploits therelative volatility (i.e., the boiling points) of the chemical compounds in the feed stream. Thosecompounds that are more volatile (i.e., have a lower boiling point) want to concentrate in thedistillate stream, while those compounds that are less volatile (i.e., have a higher boiling point) wantto concentrate in the bottoms stream. In the conceptual diagram, the set of process units operatesas a steady-state system. The system is the mixture of chemical compounds (or components) passing into, through, and from the distillation column.

Column Diagram Assumptions

Reboiler

R

QC Condenser

Stage 3

Feed

F Feed

Stage 2

Distillate

D

Stage 1 Reflux

BottomsB

Q R

T

P

n

Z

F

F

F

F

T P

n

X

D

D

D

D

T

P

n

X

B

B

B

B

1. continuous process

2.

steady state3. no chemical reaction4.

neglect KE and PE changes5.

no shaft work

Heat ( ) is added to the reboiler to vaporize part of the liquid and produce the vapor

flow that travels up the column to the condenser. The other part of the liquid in the reboiler is

draw off as the bottoms stream. Heat ( ) is extracted in the total condenser to convert the

saturated vapor to a saturated liquid. Part of this liquid is then reflux down the column to thereboiler. The other part is drawn off as the distillate stream.

Q R

QC

A feed stream enters on one of the equilibrium stages. At the temperature and pressure ofthis stage, a vapor-liquid equilibrium is established, and a vapor stream flows to the stage abovewhile a liquid stream flows to the stage below. At each stage in the column, this sameequilibrium process occurs at a different temperature and pressure, causing the components toseparate by their difference in boiling points. The more volatile components concentrate in thevapor, and the less volatile components concentrate in the liquid. The temperature and pressure profiles in the column are similar, going from higher values at the reboiler to lower values at thecondenser.

Beef, Inc. L-1 7/29/98




As show in the three-stage diagram above, a distillation column consists of many smaller process units that are tied together. A mathematical model for the whole column is simpler to present by modeling each section of the column—condenser, stages, reboiler—separately andthen show how they overlap. The mathematical models for the total condenser, three stagesincluding a feed stage, and the reboiler of a distillation column are given below. The column is atsteady state with no chemical reaction or shaft work and negligible kinetic and potential energy

changes. In each math model, the independent set of equations contains the material and energy balances, the thermodynamic functions for molar enthalpy, vapor-liquid equilibrium (vle)functions, temperature and pressure relationships and a component mole fraction sum. Thedegrees-of-freedom (DOF) analyses below show the number of variables that must be specified tosolve each model separately. An overall degrees-of-freedom analysis is also shown for all thesmaller models combined. The overlapping of the process units causes variables and equations to be duplicated when determining the DOF. Each process unit duplicates the process statevariables of two streams (i.e., the temperature, pressure, flow rate, and composition) and the molarenthalpy functions of two streams. To solve the entire distillation column, (nc + 10) variablemust be specified.

The mathematical algorithm for solving the entire column is given below. Because of the

dependence of each process unit on the others, the equations must be solved simultaneously. Allunknown variables are iterated in all equations until all the equations equal zero. Other possiblesimulation algorithms supported by the HYSYS software are summarized below.



i is the pressure of process stream i, kPa.ni is the bulk molar flow rate of process stream i, kgmol/h.

,ni j


nc is the number of chemical components or compounds in the mixture. zi j, is the bulk mole fraction of component j in process stream i;

vector Z i means all elements z z for stream i. zi i i n, , ,, , ,1 2 … c

xi j, is the liquid mole fraction of component j in process stream i;

vector X i means all elements x x xi i i n, , ,, , ,1 2 … c for stream i.

yi j, is the vapor mole fraction of component j in process stream i;

vector Y i means all elements y y yi i i n, , ,, , ,1 2 … c for stream i.

R is the reflux ratio—the reflux flow rate of R over distillate flow rate of D.V f i,

is the molar vapor fraction of the phase equilibrium in process stream i.

K j is the equilibrium vaporization ratio or K-value of component j.

H i is the molar enthalpy of process stream i, kJ/kgmol.Qu is the energy duty of the condenser or reboiler unit u, kJ/h.

ΔPu is the pressure drop of the condenser or reboiler unit u, kPa.



Beef, Inc. L-2 7/29/98




Condenser Diagram

sat’d

liquid

sat’d

vapor

QC

Distillate

D

Reflux

R

V1

Condenser Mathematical Model

1

2

3

4

5

6

7

8

9

1

1 1

1 1

1 1 1 1

0

0

0

0

0

0

0

0

1 2

( )

=

− − =

⋅ − ⋅ − ⋅ =

⋅ − ⋅ − ⋅ − =

− =

− =

− =

− =

− =

−

( )

( )

( )

( )

( )

( )

( )

( )

hmix , ,

hmix , ,

hmix , ,

, , , , , ,

n n n

n y n x n x

n H n H n H Q

H T P Y

H T P X

H T P X

T T

P P

R n

V R P

V V j R R j D D j

V V R R D D C

V V V V

R R R R

D D D D

R D

R D

R

j ncfor

/

vle , ,

, ,

,

, , ,

n

x x

T P V X

P P P

D

R j D j

D D f D D

V D

j nc

nc

=

− =

− = =

− + =

( )

( )

( )

= ⋅

= ⋅

= ⋅

=

0

0

0 0

0

10

11

12

15

2 10

5

1 2

1

for

bubble - point temperature

# vars

# eqns

DOF

Δ

3 nc +

+

1 nc +

Example knows: T P n Y P RV V V V D1 1 1 1, , , , ,

Beef, Inc. L-3 7/29/98




Stage 1 Diagram

V1

Stage 1

R

V2 L1

Stage 1 Mathematical Model

1

2

3

4

5

6

2 1 1

2 2 1 1 1 1

2 2 1 1 1 1

2 2 2 2

1 1 1

0

0

0

0

0

1 2

( )

=

+ − − =

⋅ + ⋅ − ⋅ − ⋅ =

⋅ + ⋅ − ⋅ − ⋅ =

− =

− =

−

( )

( )

( )

( )

( )

hmix , ,

hmix , ,

hmix , ,

, , , , , , ,

n n n n

n y n x n y n x

n H n H n H n H

H T P Y

H T P X

H T P Y

V R V L

V V j R R j V V j L L j

V V R R V V L L

V V V V

R R R R

V V V V

j ncfor

1

1 1 1 1

1 1

1 1 1 1

1 1

1 1

1 1

1 1

1

1

0

0

0

0

0

0

0

0

1 0 0

7

8

9

10

11

12

13

14

18

3 11

7

1 2

1 2

=

− =

− ⋅ =

− =

− =

− =

− =

− =

− =

( )

( )

( )

( )

( )

( )

( )

( )

= ⋅

= ⋅

= ⋅

=

=

=∑

hmix , ,

kvalue , , ,

.

, ,

,

, , ,

, , ,

H T P X

y K x

K T P Y X

T T

T T

P P

P P

x

L L L L

V j j L j

j V L

V L

V

V L

V

L j

j

nc

j nc

j nc

nc

for

for

# vars

# eqns

DOF

5 nc +

+

2 nc +

Example knows: T P n Y T P n X PV V V V R R R R2 2 2 2, , , , , , , , 1

Beef, Inc. L-4 7/29/98




Feed Stage 2 Diagram

V3

FeedF Feed

Stage 2

V2 L1

L2

Feed Stage 2 Mathematical Model

1

2

3

4

5

3 1 2 2

3 3, 1 1 2 2 2 2

3 3 1 1 2 2 2 2

3 3 3

0

0

0

0

1 2

( )

=

+ + − − =

⋅ + ⋅ − ⋅ − ⋅ − ⋅ =

⋅ + ⋅ + ⋅ − ⋅ − ⋅ =

− =

−

( )

( )

( )

( )

hmix , ,

hmix ,

, , , ,

, , ,

n n n n n

n z n y n x n y n x

n H n H n H n H n H

H T P Z

H T P

F V L V L

F F j V V j L L j V V j L L j

F F V V L L V V L L

F F F F

V V V

j ncfor

,

hmix , ,

hmix , ,

hmix , ,

kvalue , , ,

, , , , ,

, , ,

Y

H T P X

H T P Y

H T P X

y K x

K T P Y X

T T

T T

P P

P P

V

L L L L

V V V V

L L L L

V j j L j

j V L

V L

V

V L

V

j nc

j nc

3

1 1 1 1

2 2 2 2

2 2 2 2

2 2

2 2 2 2

2 2

2 2

2 2

2 2

0

0

0

0

0

0

0

0

0

0

6

7

8

9

10

11

12

13

14

1 2

1 2

=

− =

− =

− =

− ⋅ =

− =

− =

− =

− =

− =

( )

( )

( )

( )

( )

( )

( )

( )

( )

=

=

for

for

15

22

3 12

10

2

11 0 0( )

= ⋅

= ⋅

= ⋅

=∑ − = x L j

j

nc

nc

, .

# vars

# eqns

DOF

6 nc +

+

3 nc +

Example knows: T P n Y T P n X T P n Z PV V V V L L L L F F F F 3 3 3 3 1 1 1 1, , , , , , , , , , , , 2

Beef, Inc. L-5 7/29/98




Stage 3 Diagram

Stage 3

V3 L2

V4 L3

Stage 3 Mathematical Model

1

2

3

4

5

6

4 2 3 3

4 4 2 2 3 3, 3 3,

4 4 2 2 3 3 3 3

4 4 4 4

2 2 2 2

3 3

0

0

0

0

0

1 2

( )

=

+ − − =

⋅ + ⋅ − ⋅ − ⋅ =

⋅ + ⋅ − ⋅ − ⋅ =

− =

− =

−

( )

( )

( )

( )

( )

hmix , ,

hmix , ,

hmix

, , , , ,

n n n n

n y n x n y n x

n H n H n H n H

H T P Y

H T P X

H T

V L V L

V V j L L j V V j L L j

V V L L V V L L

V V V V

L L L L

V V

j ncfor

, ,

hmix , ,

kvalue , , ,

.

, , ,

, , ,

P Y

H T P X

y K x

K T P Y X

T T

T T

P P

P P

x

V V

L L L L

V j j L j

j V L

V L

V

V L

V

L j

j

nc

j nc

j nc

nc

3 3

3 3 3 3

3, 3,

3 3 3 3

3 3

3 3

3 3

3 3

3,

1

0

0

0

0

0

0

0

0

1 0 0

7

8

9

10

11

12

13

14

18

3 11

1 2

1 2

=

− =

− ⋅ =

− =

− =

− =

− =

− =

− =

( )

( )

( )

( )

( )

( )

( )

( )

= ⋅

= ⋅

= ⋅

=

=

=∑

for

for

# vars

# eqns

DOF

5 nc +

+

2 nc + 7

Example knows: T P n Y T P n X PV V V V L L L L4 4 4 4 2 2 2 2, , , , , , , , 3

Beef, Inc. L-6 7/29/98




Reboiler Diagram

sat’d

vapor

sat’d

liquid

sat’d

liquid

Q R

Bottoms

BL3

V4

Reboiler Mathematical Model

1

2

3

4

5

6

7

3 4

3 3, 4 4

3 3 4 4

3 3 3 3

4 4 4 4

4

0

0

0

0

0

0

0

1 2

( )

=

− − =

⋅ − ⋅ − ⋅ =

⋅ − ⋅ − ⋅ + =

− =

− =

− =

− ⋅ =

( )

( )

( )

( )

( )

( )

hmix , ,

hmix , ,

hmix , ,

, ,

, ,

, , ,

n n n

n x n y n y

n H n H n H Q

H T P X

H T P Y

H T P X

y K x

L V B

L L j V V j B B j

L L V V B B R

L L L L

V V V V

B B B B

V j j B j

j ncfor

for

j nc

j ncK T P Y X

T T

P P

x

P P P

j B B V B

V B

V B

L j

j

nc

R L B

nc

=

=( )

( )

( )

( )

( )

= ⋅

= ⋅

= ⋅

− =

− =

− =

− =

− + =

=

∑

1 2

1 28

9

10

11

12

14

3 9

5

4

4

4

3,

1

3

0

0

0

1 0 0

0

, , ,

, , ,kvalue , , ,

.

for

# vars

# eqns

DOF

Δ4 nc +

+

1 nc +

Example knows: T P n X P n L L L L B3 3 3 3, , , , , B

Beef, Inc. L-7 7/29/98




Column Degrees-of-Freedom Analysis

Total Number of Variables

Duplicates

Condenser 3⋅nc + 15

} 2⋅nc + 8

Stage 1 5⋅nc + 18

} 2⋅nc + 8

Feed Stage 2 6⋅nc + 22

} 2⋅nc + 8

Stage 3 5⋅nc + 18

} 2⋅nc + 8

Reboiler 4⋅nc + 14

23⋅nc + 87

Duplicates 8⋅nc + 32 8⋅nc + 32

Total Variables 15⋅nc + 55

Each process unit duplicates the temperature, pressure, flow rate,

composition, and enthalpy for two streams (i.e., 2⋅nc + 8).

Total Number of Equations

Duplicates

Condenser 2⋅nc + 10

} 2

Stage 1 3⋅nc + 11

} 2Feed Stage 2 3⋅nc + 12

} 2

Stage 3 3⋅nc + 11

} 2

Reboiler 3⋅nc + 9

14⋅nc + 53

Duplicates 8 8

Total # equations 14⋅nc + 45

Each process unit duplicates the enthalpy functions for two streams.

Overall Degrees of Freedom

Number of Variables = 15⋅nc + 55

Number of Equations = 14⋅nc + 45

DOF = 1⋅nc + 10

Example knows: T P n Z P P P P P R nF F F F D B, , , , , , , , , , 1 2 3 B

Beef, Inc. L-8 7/29/98




Mathematical Algorithm

Ψ Ψ Ψ Ψ D R B C R F D B DQ Q P P P P P R n

f all unknowns all equations

until f all unknowns

, , , , , , , , , , , =

⇐

=

column

Iterate on in

1 2 3

0

all unknowns


The above mathematical algorithm is for a simple distillation column with three stagesand the feed entering on the second stage. HYSYS supports the simulation calculations for arigorous distillation column that may contain up to 200 stages. If the process state of the feedstream to a rigorous column is fully defined (i.e., the temperature, pressure, flow rate and composition

are known) and some column characteristics are given, only two additional variables are requiredto calculate all unknowns, as depicted in the HYSYS simulation algorithms below:

Ψ Ψ Ψ Ψ

Ψ Ψ Ψ Ψ

D R B C R F D B S FS D

D R B C R F D B S FS B

Q Q P P N N R n

Q Q P P N N R n

, , , , , , , , , ,

, , , , , , , , , ,

=

=

columna

columnb

where N S is the number of column stages, N FS is the feed stage number, and R is the reflux

ratio.

The above two column algorithms are but a few of the many HYSYS simulationalgorithms for this unit operation. For the rigorous column, HYSYS calculates all of the

equilibrium stage pressures from the distillate and bottoms pressures ( P D and P ). The number of

stages, the feed stage number, and the reflux ratio can be estimated using the shortcut column operation in HYSYS. The last two specified variables in the rigorous column algorithm can beany combination of the reflux ratio, distillate flow rate, reflux flow rate, bottoms flow rate,condenser duty, reboiler duty, and exit component compositions.

B

Beef, Inc. L-9 7/29/98

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