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CHEMWORK Collection

Version 2.1

Software Package Instruction Manual

Saeid Rahimi

July 2006

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TABLE OF CONTENTS

1. ABOUT CHEMWORK 3

2. GENERAL REQUIREMENTS 3

3. LINE SIZING 4

4. PUMP HYDRAULIC CALCULATION 12

5. CONTROL VALVE HYDRAULIC CALCULATION 17

6. UNIT CONVERSION 22

7. PRESSURE SAFETY VALVE CALCULATIONS 23

8. TWO PHASE SEPARATOR SIZING 30

9. CONTACT 35

10.REFERENCES 35

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1. About Chemwork Chemwork collection version 2.1 is a collection of calculation modules in visual basic environment. This process engineering software package covers all hydraulic calculation including single and two phase line sizing, pump and control valve hydraulic calculation and two phase (liquid / vapor) separator sizing. This software also sizes psv and its inlet line for vapor, liquid and steam and calculates psv relief load for fire case and liquid thermal expansion based on API-520 and 521. Calculation outputs are generated in two forms: 1) Summarized calculation sheet in MS Excel Worksheet. 2) Equipment Data sheet based on API and other related Standards

The following figure depicts the main page of Chemwork Collection environment.

2. General Requirements Windows 98 or above Microsoft Excel 97 or above Adobe Acrobat Reader 5.0 or above

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3. Line Sizing

3.1. Single Phase Single-phase line sizing for liquid and vapor phase is carried out in this module.

3.1.1. Input Data The schematic view of input data tabs have been shown in the following figures.

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3.1.2. Calculation Results The major parameters calculated by software as a calculation results are as follows: • Reynold 's No which is calculated from

DWDUReµ

=µ

ρ=

• Friction factor for all flow regimes is calculated from Swamee–Jain equation except laminar flow that program utilizes 64/Re rule.

• Liquid or vapor velocity in pipe in m/sec or ft/sec. • Pipe internal diameter and pipe internal area are extracted from Fitting Sheet

according to input schedule and nominal pipe size. • Pressure drop is calculated from the following equation in bar or psi:

g2U

DLfP

2

=∆

The following picture shows Calculation Result Tab.

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3.1.3. Line Size Selection The general requirements for line size selection fall into two main categories:

Pressure drop Velocity Limitation

Pressure drop and velocity limitation shall be determined by project design criteria but in absence of this document user can determine line size using the tables available in the software.

An online technical help is available in the software toolbars to make the line size selection easier and faster.

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3.2. Two Phase Two phase line sizing is done according to Lakhart - Martinnelli method and Baker and Aziz map which is used for determination of flow regime in horizontal and vertical line respectively.

3.2.1. Input data

The schematic view of input data tab has been shown in the following figure.

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3.2.2. Calculation Results The major parameters calculated by software as a calculation results are follows:

• Liquid and vapor superficial velocity are liquid and vapor velocity based on total pipe

area not liquid and vapor section area in the pipe. • Liquid and vapor superficial Reynold’s No are calculated using liquid and vapor

superficial velocity • Mixture density is calculated by:

V

V

L

L

VLm WW

WW

ρ+

ρ

+=ρ

• Mixture velocity is a major parameter in determination of velocity criteria for line size selection (Refer to 3.3.3.).

• Bx and By are baker map parameters that are used for determining flow regime for Horizontal line and Nx and Ny are used in Aziz map for vertical up flow.

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The following pictures show the Baker and Aziz map respectively.

The generated calculation sheet for single and two phase line sizing in MS Excel as a software print out is attached hereunder.

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4. Pump Hydraulic Calculation Pump Calculation software covers pump hydraulic calculation including determination of pump suction and discharge pressure and consequently pump differential pressure, available NPSH and power calculation. This calculation cab be carried out for pump that have two separate destination with completely different condition.

Drawing a sketch of system (simplified PFD) including all equipment (vessel, tank, pump, heat exchanger, control valve, filter, strainer, fittings and etc.) also elevation data, pipe size, operating pressure and equipments pressure drop may be useful for checking the input data and calculation. This simplified PFD can be drew by common software such as Paint, Visio or AutoCAD and inserted in assigned area for "Sketch" with Double click on the sketch area. Calculation results are available in both API datasheet and calculation sheet.

4.1. Input Data The schematic view of Input Data Tabs have been shown in the following figures.

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4.2. Calculation Results Main calculated parameters by software are listed below: • Pump suction head in meters and pump suction pressure in bara. • Pump discharge head in meters and pump discharge pressure in bara. • Pump differential head and pump differential pressure. • Pump shutoff pressure in barg. • Available Net Positive Suction Head (NPSHA). • Pump hydraulic, brake horse and electric drive powers in kW. The above-mentioned parameters have been shown in the following picture. The hydraulic sketch is attached to the related pump calculation in the Hydraulic Sketch Tab as shown in the next picture as well. The software results are exported into calculation and datasheet format, which is prepared in MS Excel Worksheet.

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A sample API data sheet of pump, which is automatically completed by software is attached hereunder.

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5. Control Valve Hydraulic Calculation Control valve calculation software covers control valve hydraulic calculation including determination of control valve suction and discharge pressure and consequently control valve pressure drop at minimum, normal and maximum flow rate for control valve located in pump discharge or other locations in both liquid and vapor services.

The Calculation Result Tab of software has been depicted in the following picture.

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Due to similarity of input data of control valve hydraulic with pump hydraulic calculation the pictures related to control valve hydraulic calculation module have not be shown in the following pages. Calculation results are available in both datasheet and calculation sheet format. The print out of software as a calculation sheet is presented in the following pages.

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6. Unit Conversion Unit conversion software consists of one single excel sheet for changing the input value to other common dimensions. Unit conversion of the following engineering parameters can be handled by this software: Length Area Volume Mass Velocity Pressure Mass flow Volume flow Mole flow Mass density Dynamic viscosity Kinematic viscosity Energy Latent heat Power Specific heat Heat transfer coefficient Conductivity Temperature Time

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7. Pressure Safety Valve Calculations Pressure safety valve calculation section is including six separate modules including three module for pressure safety valve sizing in liquid, vapor and steam services and two modules for relief rate calculation at fire and thermal expansion emergency case and one module for sizing of inlet line of PSV.

7.1. Pressure Safety Valve Sizing 7.1.1. Input Data

The schematic view of Input Data Tabs has been shown in the following figures.

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7.1.2. Calculation Results

The Calculation Result Tab of software has been depicted in the following picture.

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7.2. External Fire Relief Rate

Fire module performs relief rate calculation for wetted and unwetted Equipment exposed to external fire either vertical or horizontal according to API recommended practice. The schematic view of Input Data Tab has been shown in the following figures.

7.3. Liquid Thermal Expansion Relief Rate

This module calculates the required relief load due to liquid thermal expansion with getting the following input data:

7.4. PSV inlet Line Sizing

PSV inlet line sizing shall be determined by use of an iterative method on nominal pipe size to reach acceptable pressure drop.

As shown in the following pages, the results of PSV sizing can be exported to either calculation sheet or datasheet and the relief rate and PSV inlet line sizing calculation results are available as a calculation sheet in the Excel Worksheet format.

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Fire relief rate calculation print out is as follows:

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PSV Sizing Calculation sheet is depicted in the following picture:

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The PSV inlet line sizing print out is attached hereunder:

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The completed datasheet is attached hereunder.

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8. Two Phase Separator Sizing 8.1. Vertical Vessel

Vertical vessel module accomplishes vessel sizing for both mist eliminator and no mist eliminator type. It also sizes a vessel with getting L/D ratio or vessel diameter from user.

This module also calculates the minimum nozzle diameter based on velocity or ρv2 limitation criteria.

8.1.1. Input Data The schematic view of Input Data Tabs has been shown in the following figures.

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8.1.2. Calculation Results The following parameters are the main result of software:

• K value that represents separation efficiency. • Vapor critical velocity is obtained from

UT = ×ρ

ρρ − 5.0

V

VL )(K Correction factor due to service

Correction factor is only applicable to mist eliminator type. • Vapor velocity by multiplying "vapor / critical velocity ratio" to above mentioned

critical velocity. • Height between different desirable process levels. • Vessel diameter based on calculated vapor velocity. • Vessel height according to input required height and hold up time.

The Calculation Result Tab of software has been depicted in the following picture.

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The main print out of this module is exported to MS Excel Worksheet, which has been shown in the following pages.

8.2. Horizontal Vessel

Horizontal vessel input and data and calculation results tabs are similar to above sections.

The software printout regarding to vertical and horizontal vessel sizing is attached in the following pages:

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9. Contact Please contact below email addresses for further information you may need:

S.Rahimi@gmail.com ContactUs@chemwork.org

10. References • Churchill, S. W., Chemical Engineering, vol. 84, No. 24, Nov. 7, 1977, pp. 91-92. • Baker, O., Oil & Gas Journal. July, 26, 1954. • Lockhart, R. W. and Martinelli, R. C., Chemical Engineering Progress, Vol. 45, 1949,

pp. 39-48. • Rafik Soliman, "Two phase pressure drop computed", Hydrocarbon Processing, April

1984, pp. 155-157. • C. E. Yamashiro, L. G. Sala Espiell and I.H. Farina, "Program determines two phase

flow", Hydrocarbon processing, December 1986, pp. 46-47. • American Petroleum Institute, "Sizing, Selection, and Installation of Pressure-

Relieving Devices in Refineries", API recommended practice 520, 6th edition, March 1993.

• American Petroleum Institute, "Guide for Pressure-Relieving and Depressuring System", API recommended practice 521, 4th edition, March 1994.

• American Petroleum Institute, "Flanged Steel Safety-relief Valves", API recommended practice 526, 3rd edition, February 1984.

• W. Y. Svrcek, W. D. Monnery, "Design Two-Phase Separator within the right limits", Chemical engineering Progress, October 1993, pp. 53-60.

• R. Kern, "How to Size process piping for two phase flow", Hydrocarbon Processing, October 1969.

• GPSA Engineering Data book, 10th edition, 1994. • Flow through Flow of fluids through valves, fittings and pipe, Crane Co. Technical

paper No. 410, 1985.