tricks of the trade

Chapter 1 Analyzer 1-1

Chapter 1 Analyzer Interface

The OLI Studio is a single- and multiple-point chemical calculator. Its basic action is to calculate the equilibrium properties of user-entered inflows (e.g., NaCl, CaCO3) and conditions (T, P). The StreamAnalyzer developers take this simple calculation and combine it with a series of functions to create software that computes engineering and laboratory applications; evaporation system, separation processes, corrosion rates, pH titrations, etc. When you start OLI Studio you are opening the main portal to several products,

StreamAnalyzer, CorrosionAnalyzer, and ScoreAnalyzer

StreamAnalyzer is written in Visual C++ and is designed to have the look and feel of Microsoft-type software.

Analyzer Components

StreamAnalyzer

StreamAnalyzer is the primary calculation interface of OLI Studio. It contains the following core components:

Thermodynamic Frameworks Public and Specialized Databases Redox Half Reactions Phase Selection and Manipulation Names Manager Units Manager Stream and Mix-Block Windows Single and Multiple-point Calculation windows Plotting and Reporting Features and Customization tools Water Analysis charge and pH reconciliation

StreamAnalyzer is stand-alone software. It requires no additional components to run basic calculations. Nearly all user time and calculations are performed within this interface.

CorrosionAnalyzer

CorrosionAnalyzer can be run as stand-alone software or as an add-in to StreamAnalyzer. CorrosionAnalyzer contains the mechanisms and functionality required to calculate corrosion rates and stability diagrams. Corrosion Analyzer components include:


EH-pH Stability Diagrams (real-solution Pourbaix diagrams)

Species-Species Phase Diagrams

Diffusion and Surface mediated Polarization Diagram

General Corrosion Rate Theory and Calculation engine

Local Corrosion Rate Theory and Calculation engine

Extreme Value Statistics equipment lifetime Calculation

Base Metals and Alloys Corrosion database

Corrodant and Inhibitor Database

When CorrosionAnalyzer is used as stand-alone, it creates files with a .cra extension.

SCOREAnalyzer

SCOREAnalyzer is an add-on to StreamAnalyzer. It is designed for oil and gas production operations. Its specialized window enables user to enter multi-phase analyses (gas, brine, oil) and compute simultaneously, scale tendencies and corrosion rates. SCORE contains most of the Analyzer functionality and includes the following features:

Input window for entering oil, gas and brine analyses

A specialized Oilfield Database

SCOREAnalyzer can also be run as standalone software and creates files with a .sca extension.

Analyzer Screens The main Analyzer window contains five sections, the Tree View, the Action view, the Calculation Status Window, the Calculation/Report Window and the Menu Bar. All Analyzer components, Stream, SCORE, and Corrosion (and future products) have the same (or similar) view and functionality. From easiest to lengthiest the sections are described below:

Tree View

The tree view contains the list of streams and calculations that are active within a file. As shown in the figure to the left, the view contains the icons and names of each action in a hierarchical tree. There are currently three levels, Global, Stream, and Calculation.

Global Level

The Global level is the uppermost tree structure, and sets the files global parameters. Any settings made are transferred to all stream icons below it (with a few exceptions discussed later). There is only one Global icon.

Stream Level

The Stream Level is next in the hierarchy and is where users create new streams and enter inflow components and mass/concentrations. There are

three stream icons, , , and . No calculations are performed in the Stream level.

Calculation Level

Subordinate to the Stream is the Calculation level, where all calculations are performed. There are several calculation types


The Single Point calculation, , is the most common. It computes the properties for a stream at one set of conditions. There are many conditions the user can select or create, including, isothermal, dew point, bubble point, precipitation point, or custom. These and other calculations are discussed in this training manual.

The Multiple Point, or Survey calculation, , is a series of single-point calculations in which independent variable such as temperature varies with each calculation (e.g., a temperature survey). Up to two variables can be adjusted simultaneously, and a third can be fixed (e.g., pH or bubble point pressure/temperature). There are several examples of multiple point calculations in the manual.

The Chemical or Stability Diagram, , is a phase stability plot. Chemical diagrams compute the phase stability region across a two-independent-variable range. An example would be Calcite stability when a pH and CO2 are allowed to vary. This diagram is often used to predict the Redox and pH stability of metals in solution. They are also known as real-solution Pourbaix diagrams.

The Corrosion Rate calculation, , computes the general and localized corrosion rates of metals and alloys. They contain both single- and multiple-point calculations. In future versions (Version 2.1.4 is current), there will be a fourth, fifth, and sixth calculation level, all subordinate to the stream level.

Mix Block and Composite Water Analysis

Two exceptions to this hierarchy are the Mix Block and Composite Water Analysis. They exist in the Stream Level and can perform calculations. The Mix

block, , enables the user to mix two or more streams and compute the resulting properties. The mixing ratios can be fixed or adjusted.

The Composite block is a tool used to combine duplicate (or more) water analyses to create an average composition.

Action View

This view contains selectable action icons. Each icon represents either a new stream input or new calculation. These icons include ADD:

New SCORE Analysis

New Stream

New Water analysis

New Composite Water Analysis

Mix Block

Single Point Calculation

Multiple Point (survey) Calculation

Stability Diagram

Corrosion Rate Diagram

The first three are Streams and when selected start new chemistry. The next five are Calculations and when selected add a calculation window to the selected Stream. The last icon, Composite Analysis combines multiple water analyses into a single stream for further calculations.


Calculation Status Window

This window, often anchored to the bottom contains calculation and system information, including

Calculation progress,

Error information,

Temporary file locations, and

Other text pertinent to producing a successful operation.

If not visible, you can open it by selecting View>Toolbars>Calculation Output from the menu.

Menu Bar

The Menu Bar contains the customization options.

File

The File menu contains the standard Windows actions of Open, Save, Print, etc. In addition, this menu contains an Import feature that lets users enter stream data from other simulation software.

Edit

The Edit menu includes an abbreviated Microsoft-style action list. The actions of note are:

Clear Results Removes all calculation output information Clear Status Stops or removes a calculation from the Queue

Streams and Calculations

The Streams and Calculations menu contains the same functions as the Action window.

Chemistry

The Chemistry menu contains functions for modifying the stream chemistry. It contains several sections, including,


Pre-built Models users create a single, specialized model and port it to or from other application files.

Templates users create a series of standard input component sets. For example, a standard seawater or process stream.

Model Options a multi-part tool that modifies the stream or calculation chemistry. The Model Options window contains the following setions

Thermodynamic Framework two frameworks are available Databases Any installed databases are present for use Redox Subsystems- oxidation reduction reactions can be turned on or

off, and Phase Behavior phases can be turned on or off. In addition, specific

solids phases can be selected or removed.

The Chemistry Model editor is the is the most commonly used menu item.

Tools

This menu item contains several features.

Component Search users search for a particular component within the database

Names Manager users select the style that their input and output chemistry is viewed. Styles include chemical formula, common names, OLI Variable name, or standard IUPAC names.

Names Dictionary - users can to create and edit their own common names.

Units Manager users modify the input and output units. Standard settings include English, Metric, and SI.


The Edit List Users create Custom unit sets that meet particular applications. There are several hundred units from which to create the set.

View, Window, Help

These menu options contain useful tools that are used occasionally. The reader is encouraged to review the options in these menus.

Calculation Window

The Calculation window is where the user will spend the vast majority of their time. This window looks the same for all Streams and Calculations with subtle, but significant differences.

The Top section contains the available-window tabs. The tabs differ with tree level and calculation type.

Global Level - the Explorer Tab is visible Stream/LabAnalysis Level - the Description, Definition, Report, and (if

active) Model tabs are visible. Calculation Level - the above tabs plus the Plot tab are visible.


All fluid properties computation is done in the calculation window. The Window is divided into three sections. The left-side Grid is where inflow components, inflow mass, and process conditions are entered. The upper right contains calculation types and specifications. The bottom right contains the calculation summary. The tabs at the bottom show what input and output screens are available. The default screen is the input. The above screen shows a five-point temperature survey. Each tab represents the output of the specific points in that survey.

Plot Window

The Plot window is straightforward. The key items are the Curves and Options buttons, and the right-mouse-click. Variables are changed using the Curves button. Plot formats are changed using the Options button or the right-mouse click.

Report Window

The Report window is also straightforward. There are thirteen report sections. They can be selected and modified by clicking on the Customize button. An Export feature is used to send the information to Microsoft Excel.

Chapter 2 Analyzer Mechanics, Single Point Calculations 2-9

Chapter 2 Analyzer Mechanics, Single Point Calculations

Introduction StreamAnalyzer can be viewed as free-form, electrolyte software. The free-form refers to its flexibility in defining chemistry or process pathways without task-specific directions or pre-defined recipes that are designed to produce a specific outcome. It is this flexibility that you will learn to manipulate. Thus, you will gain familiarity with the various calculations, the chemical databases, and the features, which you will use to meet your targeted goals.

Free-form software can be difficult to learn because there are no specific conclusions to meet. Thus, the Tricks of Trade manual is designed to teach StreamAnalyzer features and functions, so that when you return to your office, you have the necessary ability to develop and converge your particular simulation. This chapter will not dwell excessively in thermodynamics or theory; rather it emphasizes the software mechanics.

Some of the topics we will cover include:

Calculations

Manipulating the

Simulation

Manipulating Results

Single Point

Multiple Point (Survey)

Mix Block

Secondary Multiple Point

Covariant Multiple Point

Titration curves

Boiling point curves

Solubility point and curves

Manipulating the Chemistry Model

Importing from ESP, Aspen, HYSIS, and UniSim R-360

Exporting Streams and Results

Separating phases to create new streams

Create a sequence of calculations (separate phases and add)

Plotting t

Analyzing Solids scale tendency; in range, out of range

Solids exclusion


2.1 Isothermal Calculation

Overview

An Isothermal calculation is a pre-defined composition at a fixed temperature and pressure. It is StreamAnalyzers simplest calculation. The user creates a stream, adds the composition, add a single point calculation and presses calculate.

We will start by calculating the pH of a 1.0 molal (162.2 g/kg) solution of iron (III) chloride at 25 oC and 1 atm. We will review the output to determine the pH of the solution.

How to do it

Start StreamAnalyzer

Click on the Add New Stream icon in the Action window.

Type FECL3 (FeCl3) in the grid cell below Water

Enter a value of 1.0 mol.

After a moment a splash screen appears. The icons appearing in the lower part of the splash screen show which components are installed.

The software opens into the Global window that you will populate with streams and calculations. As described in Chapter 1, the architecture is consistent in all Analyzer windows, reducing the number of views that you need to recognize.

A stream Input window appears.

Depending on your default settings, FeCl3 may also appear as Iron(III) Chloride.


Adding a single point calculation Click on the Add Calculation button and select Single Point from the drop-down menu.

Click the Calculate button.

A new window appears. It looks like the previous window except the upper-right section now contains the calculation functions.

A calculation dialog appears with information about the calculation progress. When done, it will read Calculation Complete and disappear.

Viewing the Results

Scroll down the Summary window and find the pH.

Click on the Report tab and scroll down to the Stream Parameters. The measurable properties (pH, density, and volume) are shown here.

The Summary window in the lower right of the calculation window contains a partial set of stream properties.

The pH is 2.21.

Q. Why is the pH low?

A. The acid source is Fe(III), a Lewis Acid. When added to water Fe splits H2O forming Fe(OH)x complexes, and releasing H

+ ions. By definition pH=-log(aH+), where aH+ is the activity of the H

+ ion. Thus, H+ ions are measured as pH and as their concentration increases, pH decreases.


Scroll down to the Species (True Species) section. Its about midway down the report. The true species concentrations are reported

Review the Aqueous column

Return to the Definition window.

Change the FeCl3 inflow mass to 0.0 moles.

Enter FePO4 in the grid cell below FeCl3.

Enter a value of 1.0 mole.

Calculate

(The above table contains different units then what you see on the Report tab, you will modify units in a later section)

Focus on the five Fex(OH)yz species. Fe(OH)+2 (FEIIOHION) has the highest

concentration 4.494e-3 moles(330.5 ppm). This is roughly the same concentration as the H+ (4.508 mmolal). Both confirm to the hydrolysis reaction where the product is a 1:1 ratio:

Fe+3 + H2O = Fe(OH)+2 + H+

Since the definition of pH is: pH=-log(aH+) , and in many examples aH+ can be approximated using [H+]( the molal concentration of H+) without the activity coefficient, a quick pH approximation is:

pH=log(0.004508) = 2.35

This value is close to the computed value of 2.21, the difference being the activity coefficient effect, which was ignored in our estimate.

Note that the cell containing FePO4 is white and not yellow. That is because FePO4 was entered at the Calculation level, which can be edited. All inflows entered at the Stream level cannot be edited at the Calculation level. Only their mass/concentration can be changed.

What is the pH of this stream, why?

Discussion about Lewis Acids, Acid-Base Chemistry, and Speciation


Follow-up example To reinforce the utility of this calculation we will work the following problems as a group. Below is a table of common industrial chemicals. What are the computed pHs of these materials when their concentration in water is 1 mole/kg (1 mole in 55.508 moles H2O).

The procedure is quite simple. Create a new stream and add an isothermal calculation. Then type in HCl, set the inflow to 1 mole, calculate, and document the pH. For H2SO4, type over the HCl cell with H2SO4, confirm that the flow is still 1.0 mole and calculate. Do for the rest.

Acid Chemical pH @25C/1atm Base Chemicals pH @ 25C/1atm

HCl NaOH

H2SO4 Na2CO3

H3PO4 CaCO3

HF Na3PO4

B(OH)3 NH3

Acetic Acid CaOH2

Citric Acid MgOH2

HBr

HI

Are there any unexpected results? Why is the HF pH so high? Why is there such a pH difference between MgOH2 and CaOH2?


6% acetone

in 1kg water

1 atm

6% acetone

in 1kg water

6% acetone

in 1kg water

1 atm

2.2 Calculating a boiling point

Overview

Solutions can boil (form a vapor) at a variety of conditions, adding heat, or applying a vacuum. These are bubble points. StreamAnalyzer contains a bubble point calculations.

You will compute the boiling point of a 6% acetone in water solution. When you run the calculation, remember that StreamAnalyzer do not assume an air phase. Rather, it assumes that the liquid surface is covered by a plunger at the system pressure.

How to do it?

Create a stream with the following conditions

Stream Name Bubble Point Names Style Display Name Units Set Course Units Temperature 25 C Pressure 1 Atm Total Inflow 1 kg Water 94 mass % Acetone 6 mass %

Change the Names Set to Display Name (Menu Bar>Tools>Names Manager>Display Name)

Change the Chemical framework to MSE (Menu>Chemistry>Model Options>change from Aqueous H+ to MSE H3O+)

Click on the Add Single Point Button.

Click on the Type of Calculation button and change from Isothermal to Bubble Point.

Make sure that the Temperature radio button is selected

Calculate and view the Summary box to view the boiling point temperature

Now, calculate the bubble point Pressure at 70 C.

We are using the Mixed-Solvent framework in this case. It is an important addition to the software capabilities because it incorporates the mixed-solvency of two or more liquids. Remember, acetone also has electrolyte solvency properties.

The previously grayed out radio buttons are now active. Notice that a Free Dot is next to Temperature indicating that this variable will be adjusted.

The bubble temperature is 89.53 C. The vapor amount is 5.32e-9 moles, a very small mass. StreamAnalyzer computes the bubble point by fixing the vapor mass at 10-7 moles or less then adjusts the temperature until this criterion is met.

A Bubble-Point Pressure calculation is performed the same way with the same numerical solution, except pressure is the dependent variable


Follow-up example As with the isothermal case, we will test additional compositions with this calculation. In this case, we will look at the vapor point of 10% component-water solutions at 1 atm. This is easily done by creating a new stream, changing the framework to MSE, adding a calculation, changing the calculation type to bubble point and then testing each inflow component individually.

Organic @ 10 mass%

BPT at 1atm Inorganic @ 10 mass

BPT at 1atm

methanol NaCl

ethanol CaCl2

isopropanol FeCl3

butanol Na2SO4

ethylene glycol HCl

Na3PO4


2.3 Calculating a Dew Point

Overview

StreamAnalyzer also computes a dew (or condensation) point. You will start with sour gas at a defined temperature and pressure. You will have the software computes the dew-point temperature, the point where the first liquid drop forms. Alternatively, the software predicts the dew point pressure at a fixed temperature.

How to do it?

Create a stream with the following conditions - note the units change

Stream Name Dew Point Units Set Mole Fraction Names Style Formula Temperature 120 C Pressure 100 atm Total Inflow 100 moles Water (Calc. by dif.) CH4 94 mole % CO2 3 mole % H2S 1 mole %

Click on the Add Single Point Button.

Select Dew Point from the Type of Calculation.

Make sure that the Temperature radio button is selected.

Calculate

View the Summary

As with the previous example the initially grayed out radio buttons are now active.

The temperature is 113.5 C and the pH is 3.90 a common cause gas pipeline corrosion. Note the Aqueous Phase Amount. The value is 1.0e-6 moles. StreamAnalyzer computes the dew point by fixing the aqueous mass at this value (or smaller) and adjusts the temperature (or pressure) until this criterion is met.

Q. How would you mitigate potential corrosion problems like this gas would create


Follow up Example Test the dew point temperatures at different water contents. Vary the water content from 0.1 mole% to 10 % to see how it changes. Adjust the CH4 content to change the water content.

Water Content Dew Point Temp, C

0.1 mole%

0.5

1

5

10

20

70

90


2.4 Setting the pH of a stream

Overview

One of the most common Analyzer Calculations is Set pH. The concept is quite simple and includes various applications.

The user has a measured pH and wants to adjust the inflow chemistry to create a solution with this pH

The user needs to meet an operational pH

The user is testing the impact of adding an acid or base to their system.

Regardless of the reason, the Set pH option is a useful tool from both an analytical and process perspective.

The application below is natural gas production through a pipeline. As the gas flows it cools and condenses acidic water. Your task, should you chose to accept it, is two-fold. Step #1 is to compute the gas dew point conditions including temperature and pH. Step #2 is to add sufficient alkali so that the condensed water pH is neutral. The alkaline agent you will use is methanolamine (MEA).

How to do this

Create a new stream using the following information.

Name: Produced Gas Unit Set Mole Fraction Names Style Display Name Temperature 75 C Pressure 10 atm Total Inflow 100 mol Water (calculated) C1 86 mole % C2 5 mole % C3 3 mole % iC4 1 mole % nC4 1 mole % CO2 1.5 mole % H2S 0.1 mole %

Choose Single Point from the Add Calculation button.

Select Dew Point Temperature from the Calculation Type button.

Calculate

Run through the Names Manager Options in Chapter 3 to create the hydrocarbon shortcuts. If you dont have time, then simply enter the molecular name for the C1-C4 components in the list to the left. Also, note that the inflows are in mole %. If the unit set does not exist on your machine, create it. The key units are shown in the picture to the left.

The Dew Point temperature is 63.5 C, and the condensate pH is 4.44, slightly acidic because of the 1.5% CO2.

Neutralizing the condensed water

Amines, namely methanolamine (MEA) can remove acid components from natural gas streams. Since our goal is to minimize the acidity of the condensate, how much MEA is needed to neutralize the acid gas. From a Controller/set point perspective, the question is how much MEA is needed to raise the condensed water pH to 7. Remember, the condensation temperature is 63.5C


Return to the Produced Gas stream level, and add a new calculation.

Enter MEA in the next available inflow cell.

Change the calculation type to Set pH.

Enter 7.0 pH in the Calc Parameters grid section

Enter 60 C in the Temperature cell (slightly below the dew point).

Click on the Specs button in the upper right. (a Calculation Option window appears).

Select the Use Single Titrant box

Highlight MEA in the titrant list.

Press OK to exit the window.

Calculate

Re-calculate the system using 50 C (winter temperatures).

Re-calculate using a target pH

of 8.0.

The name may change to MEXH, NH2C2H4OH, or ethanolamine depending on your name setting.

Find the total MEA added in the Summary section. The value is 1.098e-4 mole % MEA maintain a water condensate pH of 7.0. This is what the operator needs to add to prevent the condensate from becoming too acidic and corrode the pipe.

Winter pipe wall temperatures are 50C, how much MEA is required?

What if the pipe design life is 50 years, and an 8 pH is required. Do the MDEA requirements change considerably?

Lastly, we computed MEA requirements for a 100 mole stream. This particular gas field flows at 700 MMscfd. How much MEA is needed daily if to maintain a target pH of 7.0 when the minimum wall temperature is 60 C


2.5 Calculating a Precipitation Point

Overview

A precipitation point (or solubility point) computes the amount of material stably held in solution at a given temperature and pressure. In this example we start with a solution of CaCl2, MgCl2 and CO2 and compute the mass of NaOH needed to precipitate CaCO3. StreamAnalyzer sets the precipitation mass at ~10

-9 mole fraction (of the total mass). It then add/removes NaOH to meet this solid mass set point. In this case the starting pH is low, so by adding NaOH precipitation is promoted.

How to do it?

Create a stream with the following composition

Stream Name: CaCO3 Solubility Units Set ppm Aqueous Names Style Formula Temperature 25 C Pressure 1 atm (1.013bar) H2O (calculated) CaCl2 10,870 ppm MgCl2 9,325 ppm CO2 431 ppm NaOH 0.0 ppm

Click on the Type of calculation Button and Select Precipitation Point

Click on the Specs button.

Highlight CACO3 Sol in the Solids list

Highlight NAOH in the Component Inflows list.

Click OK when done.

Calculate

Review the Summary Box

The Calc Parameters section has two rows. The Precipitant is the independent or fixed variable and the Adjustor is the dependent or freed variable. Depending upon the initial saturation of Precipitant the Adjustor mass is changed until the 10-8 mole fraction solid mass is met.

The Calculation Options window contains two fields, a list of Solids on the left and a list of Component Inflows on the right. Depending on the display mode for names, some of these species may look the same.

StreamAnalyzer calculated that 268 ppm (or 0.00686 mol) NaOH is needed to saturate this solution with calcite. Also note the Solid Phase amount is 5.57e-7 or 1/108 mole fraction


Follow up Examples There are any number of precipitation point calculations that can be run, and there are several ways of running them. The first and easiest is to simply add material until it precipitates. A second way is to add an indirect component to change chemistry which in turn creates precipitation.

For the sake of simplicity, lets look at the solubility of some simple materials and add enough of that material until something precipitates. We will run the calculation at 25 and 95 C and again at 95C and 1 mole NaCl.

Start a new stream. Add NaCl as an inflow but give it no value (for now). Add a single point calculation, change it to precipitation point. Select the SPECS button and highlight NaCl precipitate and NaCl inflow. Close the window and calculate. Run again at 95C. Add the next inflow and test its solubility. As an added task, retest its solubility when there is 1 mole/kg (58000 ppm) NaCl in the water.

Material Solubility @25C

Solubility @95C

Solubility @95C and 1m NaCl

Material Solubility @25C

Solubility @95C

Solubility @95C and 1m NaCl

NaCl xxxxx2 Hg

BaSO4 Fe xxxxx xxxxx

CaCO3 Fe (turn on Redox)3, 4

xxxxx xxxxx

ZnOH2 anthracene

ZrO2 adipic acid

SnCl21 xxxxx xxxxx

AgO

1 run the calculation using SnCl2 (s) and SnO (s) as the precipitate. Note the calculation difference 2 - ignore this calculation 3 - Turn Redox on (Chemistry>Model Options>Redox tab, check the Redox box) 4 Run the calculation with Fe (s) and Fe(OH)2 (s).

Note that the inflow may not be the precipitate. For instance, the transition metals will probably precipitate as their oxides and not as entered.

Chapter 3 Analyzer Mechanics, Multiple Point Calculations 3-1

Chapter 3 Analyzer Mechanics, Multiple Point Calculations

Multiple Point (or Survey) calculations are a series of single-point calculations strung together to create plots. One or two variables can are be adjusted and the variables include temperature, pressure, component inflows, and pH. In addition, a third variable can be fixed (e.g., bubble point, precipitation point, etc.) during the complete calculation set, thus adding an additional dimension to the calculations.

The list of adjustable variables is below. You can view them by clicking on the Types of Calculation button to see them. Below are their descriptions:

Temperature Self explanatory

Pressure Self explanatory

pH The pH range and divisions are set and the software adjusts default or user-specified acid and base

to meet that set point. Plots of acid/base addition vs. pH are often the desired plot.

Composition The inflow mass of a specific component is the adjustable parameter

Embedded Single Pt The user can fix an entirely separate variable in addition to the variables adjusted in the Survey. For

example the precipitation point of a solid can be fixed during a temperature Survey to create

solubility vs. temperature envelope.

Shorthand notation The shorthand notation for indicating a Single Point isothermal calculation is:


3.1 Composition Survey - Boiling Point vs. Acetone

Overview

You will expand on the 6% acetone boiling point calculation. You will vary the acetone concentration from 0% up to 100% and compute the normal boiling point temperature. You will then recalculate the boiling point using two different pressures, 0.1 and 10 atm. Lastly, you will calculate the boiling point pressure at two temperatures

How to do it

Find the original Bubble-Point stream.

If not found, create a new stream using the following data:

Stream Name Boiling Point Curve Names Style Display Name Units Set Course Units Framework Aqueous(H+) Temperature 25 C Pressure 1 Atm Total Inflow 1 kg Water 94 mass % Acetone 6 mass %

Click on the Add Calculation button and select Add Survey

Click the Survey by button and select composition

Click the Specs button

Select Acetone from the list in the Component tab (its probably the only one there)

Click on the Survey Range tab

Enter the following values

Start 0 mass% End 60 mass% Increment 5%

Click on the Calculation Type category

Change the calculation to Bubble Point

Close the Spec window

Calculate

You should have a grid that looks like the figure below. If not, enter any missing information.

A new window appears. On the left is a Category field containing three items, Composition, Type, and Options. On the right are input tabs that change with the category chosen. Right now the tabs are Component and Survey Range.


Click on the Plot tab

Click on the Curves button in the upper right window

Add the Temperature variable to the Y-axis: Expand the Stream Parameters category from the left-side field and double click on Temperature

Remove the Dominant Aqueous variable from the Y Axis by Double-clicking on it.

Click OK to close

Review the plot

The default plot is the Dominant Aqueous versus Independent variable (acetone inflow). This plot does little for us, and we will change it

A new window appears called Select Data To Plot. The left side field contains the available plot variables. They are listed in general categories. The right side fields are the selected variables for the X, Y, Y2, and Z axis.

According to OLI software, the boiling point temperature decreases with acetone concentration down to 30 C and below. However, the normal boiling point is 56.3 C. Is this curve reasonable? No it is not, and we will discuss why next. We will also create a more accurate calculation.


Choose Chemistry>Model Options from the menu bar.

Change the thermodynamic framework from Aqueous (H+ ion) to MSE (H3O+ ion)

Press OK

Calculate

Review the modified results

Return to the Definitions tab and click on the Specs button in the upper right.

Change the Survey Range to:

Start 0 wt%

End 100 wt%

Increment 5%

Q. So, Why such an inaccurate calculation?

A. We are moving beyond the solvent capacity of the aqueous model. What? The model we are using, Aqueous H+ is accurate to about 25-35 moles/kg. at 70wt%, acetone is at 41 moles/kg, well beyond the capabilities of this particular model. We need to change models.

Now the plot looks more reasonable


Follow-up Examples Boiling point Curves are an interesting way to look at behavior of mixtures. We will test a few more for the fun of it. We will do all calculations using the MSE framework, since that give us more concentration range. It will limit us to what we can test (as of version 3.0.60 the MSE database is one-third the size of the Aqueous database).

Component 1 Range (mass%)

Methanol 0-100 by 2

Ethanol 0-100 by 2

Butanol 0-100 by 2

HF 0-100 by 2

Ethylene Glycol 0-100 by 2


3.2 Composition Survey Dew Point vs. Ethanol

Overview

This case is similar to the boiling point Survey, except we will switch the calculation around and look at the dew point. You will vary the ethanol concentration from 0% up to 100% and compute the normal dew point temperature.

How to do it

Create a new stream using the following data:

Stream Name Dew Point Curve Names Style Display Name Units Set Course Units Framework MSE (H3O+) Temperature 25 C Pressure 1 Atm Total Inflow 1 kg Water 94 mass % Ethanol 6 mass %

Click on the Add Calculation button and select Add Survey

Click the Survey by button and select composition


Select ethanol from the list in the Component tab (its probably the only one there)

Click on the Survey Range tab

Enter the following values

Start 0 mass% End 100 mass% Increment 2%

Click on the Calculation Type category

Change the calculation to Dew Point

Close the Spec Window

Calculate

When you are ready to calculate, you should have a grid that looks like the figure below. If not, enter any missing information.

Below are the screen shots of the three SPEC windows where you need to enter information..


Click on the Plot Tab

Click on the Curves button in the upper right window

Add the Temperature variable to the Y-axis by expanding the Stream Parameter category from the left-side field and double clicking on Temperature

Remove the Dominant Aqueous variable from the Y Axis by Double-clicking on it.

Click OK to close

Review the plot

There is an interesting boiling point minimum that appears on the plot. It is at ~95 mol%.


Follow-up Examples Ethanol-Water Azeotrope That Dew Point minimum at 95% is interesting and germane to those of us who had the joy of tasting Everclear in college. Lets investigate this further.

We wish to plot the dew point and bubble point curve for ethanol on the same graph. However, since the Analyzer does not have this capability, we will port the data to a graphing program and do it there.

This is what you are to do:

While the Plot tab showing the dew point curve is active, Select Edit>Copy from the menu. Open a spreadsheet (Excel, 1-2-3, etc.) or a graphing program and paste in the values.

Rerun the calculation, but change the Calculation Type from Dew Point to Boiling Point.

Select the Plot tab. The boiling point Curves should be present. Edit>Copy this data into the worksheet.

Plot the two Curves on the same graph

Now, where does the Everclear analogy fit in? The plot above shows that the two curves meet between 95 and 100% Ethanol. They have the same value and slope. As a result, ethanol cannot be distilled from water to any higher purity than 95%. This is the Everclear product.

How then is ethanol distilled to 100% denatured alcohol? using benzene. Lets test it out.

Return to the worksheet grid and add benzene below ethanol.

Click on the second Survey by.. button and change to Composition.

Open the SPECS button.

Change the ethanol range to 70 to 98 by 1.

Change the second Survey Benzene, 0 to 2 by 2.

Calculate for both dew point and bubble point.

75

80

85

90

95

100

0 20 40 60 80 100

Ph

ase

En

velo

pe

Te

mp

era

ture

Ethanol mass%

Temperature [C]

Temperature [C]


Move the data to the worksheet and plot two graphs, one with no benzene and one with benzene. What are the differences?

The space between the two curves is enough to begin separating the two materials. We were able to break the azeotrope. The trick now is to reduce the benzene required when we put this thermodynamic property to practice. That task is in the purview of the process engineer.

Lets do it several times more

The following table contains azeotropic binary systems with water. Identify the azeotrope by creating the boiling point and dew point Survey for the binary system and porting the data to a graphing program. Then break it by adding the second component or by modifying the conditions.

All calculations are performed in the MSE(H3O+) framework.

Identify the Azeotrope Break the Azeotrope Component Range

(mass%) Component 1 Range (mass%) Component 2 or

condition value(mass%)

HCl 0-50 by 2 HCl 0-30% by 1% HF 5%

HCl 0-50% by 1% Pressure 15 atm

HF 0-100 by 2 HF 20-60% by 1% Methanol 0.2%

HNO3 0-100 by 2 HNO3 25-75% by 1% HCl 0.1%

Ethanol 80 to 100 by 1

Expand the Dew Point Survey by clicking on the + adjacent to the Survey icon. Click on Point 16 of 20. Create a new stream by clicking on Add As Stream at the bottom of the window and checking the Draw off Aqueous box. Name the new Stream 95% Ethanol distillate. Change the temperature to 25C. Change units to Default (moles). Enter CaO to the inflow grid and add the equivalent amount of CaO as there is H2O (2.775 moles). Add a Single Point, isothermal calculation, and calculate.

77.5

78

78.5

79

79.5

80

80.5

81

81.5

80 85 90 95 100

Ph

ase

en

velo

pe

Te

mp

era

ture

Ethanol mass%

Dew Point0% Benzene

77.5

78

78.5

79

79.5

80

80.5

80 85 90 95 100P

has

e E

nve

lop

e T

em

pe

ratu

reEthanol mass%

Dew Point

Bubble Point

2% Benzene


3.3 Temperature and Pressure Surveys We will return to the acetone example, and run multiple composition-temperature-pressure Surveys. We will use the MSE framework and the 0-60mass% acetone Survey option.

Composition and Temperature Survey

Return to the Acetone Survey (Example 3.1)

Select the Definitions tab and click on the Specs

Change the Survey Range to:

Start 0 mass% End 80 mass% Increment 5 mass%

In the Tree view, right-mouse-click on the Survey icon and select Copy

Right-mouse-click on the Boiling Point Curve stream and select Paste

Do this twice more to create three copies of this survey.

Name the original Survey Composition Survey

Name three new copies:

Composition/T Survey Composition/P Survey Composition/T Survey (Together)

Select the Composition/T Survey.

Click on the Definition tab.

Change the Then by: Survey option from none to Temperature

Select the Specs button (either one).

Choose Var 2 - Temperature from the Category field.

The first step is to create two new calculations based upon the one we just ran. The first will be used for a Composition-Temperature Survey and the second for a Composition-Pressure Survey.


Use the following points

Start 0 End 240 Increment 60

Close the window and calculate.

Select the Plot tab. Click the Curves button (upper right).

Find the Pressure variable in the Stream Parameters category. Add it to the Y-axis and remove the Temperature variable.

Click OK to view the plot

Composition and Pressure Survey

Select the Composition/ P Survey.


Change the Then by: Survey option from None to Pressure

Select the Specs button (either one).

Choose Var 2 - Pressure from the Category field.

Click on the Point List radio button.

Click on the Add Point to create three additional points.

Enter the following:

Point 1 0.1 atm Point 2 1.0 atm Point 3 10 atm Point 4 100 atm

Click on the Calculation Type in the Category field.

The temperature variable should already be there. If not, then select the Curves button and add Temperature from the Stream Parameters list.


Change Type of calculation from Isothermal to Bubble Point (NOTE the Temperature radio button is selected).


Select the Plot tab.

Composition and Temperature Survey (Together)

Select the Composition/ T Survey (together) icon.


Change the Then by: Survey option from None to Temperature

Change the Vary radio button from Independently to Together

Select the Specs button.

Choose Var 2 - Temperature from the Category field.

Enter the following range:

Start: 0 C End 160 C Step 10 C

Click on the Calculation Type in the Category field.

Change Type of calculation from Isothermal to Bubble Point (NOTE the Pressure radio button is selected).


Select the Plot tab.

Change the Y-axis variable to Pressure

The temperature variable should already be there. If not, then select the Curves button and add Temperature from the Stream Parameters list.

Now there is one curve. Each data point on this curve is a unique acetone and temperature value. There should be 13 points altogether. At the far left, acetone is 0% and T is 0C. At the far right, acetone is 60% and T is 240C.


Follow-up examples

A two-variable Survey can be quite useful when looking at fluid properties under stress. One of the most common applications is evaluating mineral scaling risk process operations. In this case you will look at mineral scaling as fluid moves through a multiple effect evaporator.

You will enter a seawater composition and evaporate it in a hypothetical six-effect evaporator. Our interest is looking at the mineral scale mass created at each effect. This is the inflow conditions. Add it to a new Stream

Stream Name Seawater

Name Style Formula

Framework Aqueous+

Units Set Mass Fraction (change Total to ppm)

Total Inflow 1000 kg

Temperature 25 C

Pressure 1 atm

Inflow Value (ppm)

H2O 954,314 (calculated)

CA3BO32 93.99

CACO3 64.89

CAOH2 586.83

CO2 73.676

FEIIIOH3 0.56

HCL 20063.7

KOH 631.09

MGOH2 3048.55

NAOH 18902.2

SO3 2199.25

SROH2 21.71

These are the six-effect Evaporator (plus crystallizer) conditions. Add them to a survey calculation. Remember to select the Together radio button. You will also use the Point list option in the Specs window.

Point T (C) P (atm)

1 46.6 0.1

2 70.3 0.3

3 83.2 0.5

4 93.4 0.7

5 105.3 0.9

6 110 1.0

7 (xlizer) 140 1.2

Now plot some of what you think will are variables important to evaporation (e.g., vapor rate, scale tendency, scale mass, total ion concentration, viscosity, etc.).

If youre interested in Scale tendencies, youll be dismayed to find 74 potential solids, and no hint of which one is important. If you are familiar with solid-aqueous chemistry great! If not, then you may need to bull-head your way through it. Heres one way. Select 20 at a time. Make the Y-axis logarithmic. Remove all the unimportant ones by right-mouse-clicking on one of its symbols and selecting Remove. Add the next 20 and remove the irrelevant variables (values


3.4 Performing a solubility Survey

Overview

In many cases it is desirable to know the solubility (precipitation point) of a solid as a function of another variable. A frequent variable is temperature. In this example we will determine the solubility of sodium chloride as a function of temperature

How to do it?

Create a new stream using the following information

Stream Name: NaCl Names Style Formula Units Set Default Temperature 0.0 oC Pressure 1 atm H2O 55.508 mol NaCl 0.0 mole

Add a Survey Calculation

Select a Temperature Survey

Click the Specs Button

Set the range from 0 to 100 oC

Select the Calculation Type object

Click the Type of Calculation button and select Precipitation Point.

Select NaCl Sol as the precipitant and NaCl as the inflow

Click OK and Calculate.

Click the plot tab and select Customize. Select NaCl as the Y-axis variable from the Inflows section.

The default calculation is to perform each point under isothermal conditions. We want to perform a precipitation point (similar to the previous example) at each point.

Considerations

What would happen if we raised the temperature above the boiling point of water? .


Follow-up Examples

Return to the Seawater example above. You may have noticed that of the solids that formed during evaporation, three were pH-dependent, CaCO3, Mg(OH)2, and Fe(OH)3. We can prevent these solids from forming in the lower effects by keeping the pH low.

Lets rerun the survey calculation from before, but this time we will add sufficient acid (HNO3) to keep these solids from forming. We merely need to look at the 1st four effects. You will do this by adding a Precipitation Point calculation to the survey. You will use HNO3 as the inflow (add it to the worksheet grid), and you will select Mg(OH)2 as the solid. So, here are the instructions

Copy and paste the survey

Remove the 5th, 6th, and 7th temperature and pressure point

Select Precipitation point in the Calculation Type section of the Specs window

Use Mg(OH)2 as the precipitant and HNO3 as the titrant. Calculate

Plot the HNO3 inflow and pH. Whats the maximum HNO3 concentration needed (185 ppm?). How far does the pH drop? What solids remain? What if we used Fe(OH)3 as the precipitant instead of Mg(OH)2?

Here are some additional solubility examples that you may run if you have the time. What we want to take from this task is that solubility is a thermodynamic function affected by temperature, pressure, and activity coefficients. We will look at the effects of these three factors on the solubility of common materials.

Inflows 1st Parameter to adjust

Start-End-Increment

2nd Parameter to adjust

Start-End-Increment

Other adjustment

Precipitation point

Plot

BaSO4 NaCl

Temperature 0 to 150 C by 10C

NaCl 0 to 20wt% by 5%

P=10 atm BaSO4 in BaSO4 (s)

BaSO4 inflow vs. T

Anthracene Temperature 0 to 120 C by 10C

P=10 atm

Use MSE Framwork

Anthracene in Anthracene (s)

Anthracene inflow vs. T

CaCO3 Temperature 0 to 150 C by 10C

CO2 0 to 1% by 0.25%

P=10 atm CaCO3 in CaCO3 (s)

CaCO3 inflow vs. T

We can discuss the reasons for these values after this exercise is complete.


3.5 pH Survey

Overview

In the following set of examples, you will run Survey and single-point calculations on a wastewater stream, with the goal of minimizing Ni discharge. You will start with liquid waste stream containing 1850 ppm Ni. The Ni needs to be removed before the liquid enters the bioreactor. Your objective is to determine a set of conditions that satisfies a single criterion; keeping the total soluble Nickel concentration 1ppm.

How to do it

Start by creating a new stream with the following composition

Stream Name Nickel Waste Units Set ppm Aqueous (change to flowing) Names Style Formula Stream Total 1,000 kg/hr Temperature 25 C Pressure 1 atm H2O calculated NiOH2 1850 ppm NaOH --- HCl ---

Change the units from batch to flowing system

Check the ppm Units and confirm the solid mass is in g/hr

Click on the Add Calculation button. Select Add Survey

Click the Survey by button and then select pH


Select HCl from the Acid column

Select NaOH from the Base column

As discussed previously, StreamAnalyzer automatically changes species input name to the default display name. If you do not see the formula names on the screen, go to Tools>Names Manager and switch to Formula.

Since we do not want a temperature Survey which is the default, we will need to change the Survey type.

The calculate button light is grayed out which indicates that the calculation is not ready to proceed. The Summary box indicates that we require additional information.

We need to define the acid and base titrant. For this tour, we will use hydrochloric acid (HCl) and sodium hydroxide (NaOH).


Select the Survey Range tab.

You will see a number of fields,

pH Range, Selected Range, End Points, and

Step Size

Change the increment from 1.0 to 0.5

Click OK to exit

Calculate

A small calculation Output window may appear. If it does, simply close it or drag it down and lock it to the bottom of the StreamAnalyzer window.

Category - The Category field is an overall tree view of the active functions in the Specs window. The list changes depending on the type of Survey selected.

Var 1 pH This is the main spec window for the independent variable. In this particular case, the spec window is for pH.

Survey Range Tab This tab is specific for modifying the number of calculations and the range over which the independent variables will be adjusted.

pH - The pH Range field is in general a field where users can change Survey units. It so happens that there is only one option for this Survey. If however you were running a temperature Survey, you would have the choice of several temperature units, C, F, K, and R(ankin).

Selected Range - The Selected Range is the list of Survey calculations that you are performing. You can run several Survey Ranges simultaneously. For instance, you can run a 2-5 pH by 0.1, then a 7-9 pH by 0.2, and lastly a 10-11 pH by 0.25 simultaneously. In this case we will simply run one case, a 0 to 14 pH by 0.5.

End Points - The End Points field is where users define their Survey Ranges

Step Size - The Step Size field is self explanatory. Users have the choice of fixing step size or number of steps.

pH Titrant Tab This tab is specific for changing the independent variable

Calculation Options This tab will vary depending on the independent variable. It may include calculation modifiers or

The program will run for a short time. When the orbit disappears, check the summary box to see if the calculation is complete. In the tree-view, you can expand the Survey to see if all the points converged.

We can now obtain some graphical results.


Click on the Plot tab

Right-Mouse Click in the Y-

Axis area to reveal a drop-down list. One should be called Logarithmic Scale. Select it.

Click the Curves button

Remove the Dominant Aqueous variable from the Y-axis by either double-clicking it or highlighting it and selecting the left double-arrow (


Scroll down the left-hand window to find MBG Aqueous Totals.

Double-Click the NI(+2) item or select it and use the >> button.

Click the OK button

Click the Curves button and remove the Ni+2-Aq Total species by highlighting the variable and clicking on the


3.6 Secondary Multiple Point Survey

Overview

We will continue with the previous project by introducing a complicating factor. In this case it is the presence of cyanide. Cyanide forms strong complexes with nickel and disrupts efforts to separate Ni from solution.

What we would like to learn from this example is how much cyanide that the system can take before we need to look for alternative separation methods. We have already created the example stream, and do not need to do any initial setup work. Instead, we will create a new Survey calculation from the current stream, add cyanide to the inflow list and run a secondary Survey.

How to do it

Click on the Nickel Waste stream icon in the Tree view.

Select the Definition tab, if you are not already there. Click on Add Calculation and select Survey. A new Survey window will appear.

Rename the Survey pH Survey with CN

Enter the component, HCN, in the grid cell below NaOH.

Click on the Survey by button and change to pH

Click on the Then by button and change to Composition.

Select either Specs button.

HCN is a convenient way for us to add CN to the mixture. In fact, CN is probably best entered using NaCN since at moderate pHs and under real conditions this is the likely component. However by using H instead of Na, we eliminate the atomic mass that Na brings to the compound, so that if 10 ppm HCN is added, it is close to 10ppm of CN.

The Calculation area in the upper right of the window contains two Survey buttons. The first is set at temperature and the second (Then by, optional) is currently set to none. We will change the first and second Surveys to pH and Composition.

You will notice that the Category view contains several entries,


Select Var. 1 pH (if not already there)

Highlight HCl and NaOH in the Component List.

Select the Survey Range tab. Keep the range 0 to 14. Change the increment to 0.5.

Now, select Var. 2 Composition

Highlight HCN in the Component List.

Select the Survey Range tab. Ensure that ppm (mass) units appear in the Component Range field. If not change it to do so.

Change the Start and End fields to 0 and 50 ppm

Change the increment Step Size to 10 ppm

Click OK to exit.

Calculate.

Var.1 pH Var.2 Composition Calculation Type, and Calculation Options

Var.1 pH is the pH Survey specifications that we set up exactly like the previous example.

Var. 2 Composition contains the tabs for specifying variables for the secondary Survey. Two tabs are available, Component and Survey Range.

Calculation Type and Calculation Options are additional specification categories that we will discuss at a later time.

We will start with Var. 1 pH

If you view the summary field, you will see that the Survey conditions that you created are listed. There are twenty-nine pH calculations and six composition calculations for a total of 174 single-point calculations.


When the program finishes, click on the Plot tab

Click the Curves tab and remove the Dominant Aqueous.

Add MBG Ni+2 Aqueous to the y-axis.

Click OK when finished.

Return to the Definition Tab.

Click on the Then by button and change it to None.

In the Grid, change the HCN concentration from 0.0 to 10 ppm (the concentration reported at the plant.)

Calculate

Select the Plot tab

Remove Ni+2 Aqueous

Change the Y-axis to the following

Aqueous Add to the Y-Axis Ni(OH)2 NiOH+1 Ni+2 Ni(OH)3-1 Ni(CN)4-2

As before, the Dominant Aqueous is the default variable. Also the pH is the x-axis variable, and the six HCN concentrations are parametric Curves.

The plot is much cleaner, and contains six Curves, one for each HCN concentration. You will recognize the Nickel curve shape from the previous example using 0.0 ppm HCN. The five new Curves show the HCN impact on Ni solubility. Now, the minimum Ni concentration occurs at 8 pH and is 4.1e-2 mol/hr, 10000 times higher than the 0 ppm HCN case (at 10 pH).

What does this mol/hr value mean? It certainly is not a concentration, and that is our objective, to create a 1ppm Ni solution. Presently, the MBG variables can only be viewed in mol or mol/hr units. In order to convert this number to practical units we need to do some converting.

kgmge hrkg

molNimgNi

hrmolNi /42.21000670,58*12.4 2

The system is flowing at 1000 kg/hr and the atomic wt of Ni is 58670mg/mol.

Thus the minimum solubility achieved is 2.42 mg/kg (ppm). Thus, even when

CN- is at a fairly low concentration, 10 ppm, the soluble Ni requirements are no

longer maintained. Why is this?

Considerations

In the presence of CN-1 and above 7.5 pH, Ni(CN)4-2 is the dominant aqueous species. This very stable complex

increases overall Ni solubility by 10,000x. Given this stability, we can estimate Ni solubilization by merely knowing the CN addition. Ni atomic weight is 58,67, CN formula weight is 26.02. The complex Ni(CN)4

-2 is


comprised of 58.67 g Ni and 104.08 g CN. Thus, for every 10 ppm CN in solution, up to 5.64 ppm Ni dissolves. Thus, if CN concentrations exceed a few ppm, the plant will never be able to maintain a 1 ppm Ni content. For the sake of the course, lets assume that 10ppm CN- is entering the stream and there is no way to stop it. We will need some new ideas to remove nickel to below 1ppm.

Chapter 4 Analyzer Mechanics, Mixers 4-1

Chapter 4 Analyzer Mechanics, Mixers


4.1 A Mix Block Calculation

Overview

This is a simple calculation, it is two steps. First create two new streams, 0.1 molal HF and 0.1 molal CaCl2, Then you will mix them at equal amounts. What will be the mixed pH?

How to do it

Create a stream using the following information

Stream Name HF Unit Set Default Names Style Formula Temperature 30 oC Pressure 1 atm H2O 55.508 mol HF 0.1 mol

Perform a single point isothermal calculation.

Here is the shorthand notation

Add Stream > Rename Stream > Definition > Add Conditions > Add Single Point > Select Isothermal Calculations > Calculate


Stream Name CaCl2 Unit Set Default Names Set Formula Temperature 30 C Pressure 1 atm H2O 55.508 mol CaCl2 0.1 mol

Perform a single point isothermal calculation.


Mix calculation set up

Select Streams from the Menu Bar and select Add Mixed Stream.

Confirm that the Mix block is using the Default units and not the Course units. If the units set is not default, then change it.

Highlight the stream HF in the Available Streams box and click the right double-arrow (>>).

Repeat for the stream CaCl2.

Select Single Point Mix in the Type of survey button.

Select Isothermal with the Type of calculation button.

Calculate.

We have just defined two streams and we will now mix them together.

The summary box displays the results.

The pH is 1.44.

Considerations

Why the unusual pH behavior? Mixing an acid and a base should result in a neutralized solution. In this case, the pH is lower than the starting streams.


4.2 Mix Block - Neutralizing two streams

Overview

This example is a follow-up to the Mix Block examples. The purpose of this example is to familiarize the user with the three mixing options, Ratio, Proportion, and Volume. Some of this was already covered in the previous examples, and this calculation will serve as a comparison analysis.

We are going to use two refinery waste waters, a spent caustic and a spent sulfuric acid stream.

How to do it!

Create two streams with the following composition.

Stream Name Spent Caustic Unit Set Mass Fraction Names Style Formula Temperature 50oC Pressure 1 atm Stream Amount 1000 kg H2O balance NaOH 0.9 wt% CH4S 0.2 wt% NaCl 0.2 wt% H2S 0.5 wt% Phenol 0.2 wt% Naphthenic acid 0.15 wt% NH4Cl 0.07 wt%

Run a single-point isothermal calculation

Stream Name Spent Sulfuric Acid Unit Set Mass Fraction Names Style Formula Temperature 42 oC Pressure 1 atm Stream Amount 1500 kg H2O balance H2SO4 1.5 wt% Na2SO4 0.5 wt% Na2S2O3 0.3 wt% Lauric Acid 5.2 wt%

Run a single-point isothermal calculation

Review the units selected for this block. Make sure that it is set for either mass or moles (in Version 2.0 and below, mass and mole fraction units are not allowed)


Select Streams from the menu bar and select Add Mixed Stream

Name the Mix Block Titration Apparatus by Ratio

Highlight the Spent Caustic and H2SO4 streams just created and move them to the Selected field.

Select Ratio from the type of survey button.

Click the Specs button.

Set the range from 0.0 to 4.0 and change the increment to 0.25

Click on the General object in the Category field

Select Spent Caustic as the adjustable variable.

Click OK to close.

Calculate.

Click the Plot tab and select pH as the Y-axis variable (located under Additional stream parameters). Select Volume Flow Aqueous as the Y2-Axis.

The ratio calculation adjusts the amount of one of the specified streams.

By selecting this stream, you chose to adjust the Spent Caustic stream from zero four times the ratio displayed on the definition grid. In this example, a ratio of 1:1 means that 1000 kg Spent Caustic is reacted with 1500 kg Spent acid.


Considerations

The mixing results are secondary to the objective of comparing the different mixing scenarios.

Ratio Survey This survey calculation adjusts the inflow mass of the selected stream only. Its mass is multiplied by the Ratio value.

Stream Mass * Ratio = Total Inflow Mass

The second (third, fourth, etc.) stream inflows are kept constant.

Volume Survey This survey calculation adjusts the inflow volume while keeping the other stream volumes constant.

Proportion Survey The Proportion survey calculation adjusts both inflow streams using the following rule

Selected Stream Mass * Proportion = Inflow Mass

Sum of Other Stream Masses * (1-Proportion) = Other Mass

In this survey calculation, the overall inflow mass is kept constant.


4.3 How to create a titration curve?

Overview

A titration curve is the mixing of two reagents, typically an acid and base. The OLI Analyzers can mix two or more reagent streams to produce a typical titration curve. In this example a 0.1 molal solution of citric acid will be titrated against a 0.1 molal solution of sodium hydroxide.

How to do it!


Stream Name Citric Acid Names Style Display Name Unit Set Default Temperature 25C Pressure 1atm H2O 55.508 mol Citric Acid 0.1 mol

Calculate

Create a second stream using the following information.

Stream Name NaOH Names Style Formula Unit Set Default Temperature 25 C Pressure 1 atm H2O 55.508 mol NaOH 0.1 mole

Calculate

Select Streams>Add Mixed Stream from the menu bar

Name it Titration Apparatus

Highlight the Citric Acid and NaOH stream and move them to the selected field.


Select Ratio from the Type of Survey button.

Click the Specs button.

You should see the Survey Range tab. If not, then click on the Variable Ratio object in the Category section.

Set the range from 0.0 to 4.0 and change the increment to 0.05

Click on the General variable in the Category field. Highlight NaOH (if not already highlighted).

Click OK to close

Calculate.

Click the Plot tab and

X-Axis Ratio Y-Axis - pH

(pH is located under Additional Stream Parameters).

The ratio calculation adjusts the amount of one of the specified streams.

This will adjust the selected stream (selected next) from 0 to 4 times the amount displayed on the definition grid. In this case we will select the NaOH stream which is approximately 1 liter. Thus we will adjust the stream from 0 liters to 4.0 liters. The Citric Acid stream is about 1 liter.

Considerations

The equivalence point seems to occur at approximately a pH of 9.4 with a ratio of 3.0. From this we could back out the equilibrium constant for the acid.


4.4 How do you enter data into Laboratory Analyzer? StreamAnalyzer is developed to accommodate two input types, molecular and ionic. We have already seen how molecular inflows are handled. When we are working off a water analysis, we use the LabAnalyzer screens, either as a plug-in to StreamAnalyzer or in its Stand-alone version.

The LabAnalyzer databank recognizes several entries for a cation or anion. The database is populated with up to a dozen synonyms for each ion. This gives you flexibility on how to type in the name. Two examples, Na+ and CH3COO

- are shown below.

If you misspell or use an unrecognized name, the name will be moved to the neutral list and a red X appears to the left of the name you entered. You will need to delete this cell to proceed.

There are approximately 2,000 cations and anions and 15,000 synonym entries in the database. You can access the database by clicking on the down arrow within the input cell. To exit the list you need to select a species. The escape key does not work within the list.

Sodium Acetate

Na+ C2H3O2-

Na+1 C2H3O2(-)

Na(+) C2H3O2(-1)

Na(+1) C2H3O2(1-)

Na(1+) C2H3O2-1

Sodium ion(+1) Acetate ion(-1)

NAION Acetate ion (-1)

Sodium ion ACETATEION

Natrium ion

Natrium ion(+1)


How to do it

Create a new Lab Analysis Entry by clicking on the Global Icon and selecting Add Water Analysis

Enter the following Brine Analysis into the screen that opens Cations Na+ 10,000 mg/l Ca+2 500 Mg+2 1,200 Sr+2 200 Ba+2 5 Fe+2 5 Anions Cl- 19,000 mg/l SO4

-2 2,700 B(OH)4

- 180 HCO3

- 145 AsO4

-3- 12 Formate- 20 Acetate- 50 Propanate- 25 Thiocyanate- 2 H4DTPA

- 56 pH 7.8 Density 1.013 TDS 36,500 mg/l

Select Add Reconcile on the right-side of the screen. A new window appears.

Click on the Specs button and review the Electroneutrality options

A new screen appears that looks like the following

If you cannot create the correct species, you can find it using the list. Type in the first two or three characters. Then click on the down arrow to the right of that input cell. When the list appears below the cell, it should be near or even on the species you need. If you see more than one name for the same component, select it. They are synonyms.

You will note that some of the names will change. The H4DTPA- ion changes to H4(C14H18N3O10)-, because the Names Manager is set to formula. You can change this by selecting from the menu, Tools>Names Manager>Display Name or OLI Tag.

LabAnalyzer will reconcile the charge imbalance and calculate the fluid properties.

.


Electroneutrality

Dominant Ion

The largest species concentration of the deficient charge is added

In this case Na+ ion was added since there is an excess of negative charge.

Proration

An equal percentage of all deficient species is added.

Na+, Cl-

Sodium is added when there is an excess of negative charge, chloride is added when there is an excess of positive charge.

User Choice

The user specifies the cation or anion required to balance the sample.

Since there is an excess of negative charge, only the cations are available for selection with this option. 708.915 mg/L of Ca+2 is needed to balance the sample.

Make Up Ion

The specified ion is either added or subtracted to balance the charge.

With the make-up ion option, either a cation or anion can be used to adjust the Electroneutrality. Since in this example, there is an excess of negative charge, selecting a cation has the same result as the User Choice option. In the figure above, chloride ion has been selected. Since there is an excess of negative charge, 1254.212 mg of Cl- must be removed.

Make sure the Type of Balance button is set to Na/Cl and the click the OK button.

Exit the screen and return to the main worksheet

Click on the Auto NaOH/HCl button within the Reconcile pH area

Calculate

The Summary box is now updated with the current Electroneutrality


Review the Summary section

Click on the Report Tab and review the Scale Tendencies (about one-third the way down)

According to the calculation, 813 mg/l Na is needed to balance charge

In addition, 12.3 mg/l (0.34 mol/l) HCl is needed to fix the pH at 7.8

Lastly, some solids precipitated during the titration

In order to see what solids formed, we will review the Report

Three solids are calculated to precipitate (Their scale tendency =1.0), one of which is CaCO3. Since CaCO3 removal is removal of alkalinity, then the pH would naturally decrease. It is now the decision of the analyst to decide if this solid truly existed in the solution during the experiments. It is reasonable for this solid to not form, i.e., remain metastable, If that is the case, then we may remove the solids from the calculation, and allow the carbonate to remain in solution. We can review the species list and see how much carbonate mass was removed from solution.


Scroll down the report to the Species Output (True Species) section

Click on the Customize button in the upper right corner.

Click on the Species Output entry within the Category field

Next, select the Options tab

There is a Row Display field with an option: Only rows where any value is greater than..

Click on that radio button and enter the value 5.

Click OK to exit the window

From the menu, click on Chemistry>Model Options, and then click on the Phases tab.

Remove the check from the Solids entry within the Include Phases field

Make sure that the Calculate Scale Tendencies box is checked


Re-Calculate by pressing the F9 key

The Species output list is extensive, there are over 100 entries. We can reduce the list size by adding a filter located in the Customize window. Lets cut off the list a 1ppb. The new window contains formatting features that add or remove specific report sections and to also add/remove specific components within each section.

We will focus on the Species Output section of the Report

The 5 value correlates with the units chosen. For the ppm Aqueous, it is 5ppm, so any value greater than this will appear. The list length is reduced by 75%.

Solids mass is in the far right row. SrSO4 solids are 338 mg, followed by 127 mg CaCO3 and 8.4 mg BaSO4. The 127 mg (or 1.27 mmol/l) CaCO3 is equivalent of 2.54 mmol/l carbonate alkalinity. This is much more than the 0.34 mmol/l HCl added to increase pH. Thus, the CaCO3 precipitation had a greater impact on final pH then the HCl. If we re-reconcile this fluid with these solids still dissolved, we can see what the pH initially was just prior to precipitation.

(You will notice that BaSO4 is on the list, but only has a value of 3e-3 ppm, lower than this filter. This is because the solid phase is 8 mg, which exceeds the filter value for the solid phase. Therefore it also appears.)


Scroll down to the Scaling Tendencies section.

Review the top four entries

Return to the Reconciliation Tab and review the Summary section. How much NaOH was added?

Turn off the pH reconciliation

Recalculate

From the menu, click on Chemistry>Model Options, Phases.

Turn the solids back on


Calculate

Review the pH

Two sulfate and two carbonate solids are supersaturated, with BaSO4 having the greatest supersaturation. When we ran the calculation, only three solids precipitated. No SrCO3 solid formed, despite its supersaturation. This is because of competing ion effect among the four potential phases.

Instead of adding 12 mg/l HCl, 58 mg/l HCl is needed. This difference represents the impact of CaCO3 precipitation on overall pH.

Lastly, lets see what the pH is without reconciling.

The calculated pH is 8.9, much higher than the 7.8 recorded. This is a big difference and adds to the uncertainty.

There is one final calculation option; the pH when solids are turned on. Lets look at that calculation before we make a conclusion

The pH is 7.94, close to the measured value. This value is close enough to the measured pH to keep. Thus, we can probably use the system as-is, and not add any HCl. The pH will be off slightly, but with this approach, we are not changing any chemistry

Chapter 4 Analyzer Mechanics, Mixers and Water Analyses 5-1

Chapter 5 Analyzer Mechanics, Water and Oil Analyses


5.1 Entering data into Laboratory Analyzer StreamAnalyzer is developed to accommodate two input types, molecular and ionic. We have already seen how molecular inflows are handled. When we are working off a water analysis, we use the LabAnalyzer screens, either as a plug-in to StreamAnalyzer or in its Stand-alone version.

The LabAnalyzer databank recognizes several entries for a cation or anion. The database is populated with up to a dozen synonyms for each ion. This gives you flexibility on how to type in the name. Two examples, Na+ and CH3COO

- are shown below.

If you misspell or use an unrecognized name, the name will be moved to the neutral list and a red X appears to the left of the name you entered. You will need to delete this cell to proceed.

There are approximately 2,000 cations and anions and 15,000 synonym entries in the database. You can access the database by clicking on the down arrow within the input cell. To exit the list you need to select a species. The escape key does not work within the list.

Sodium Acetate

Na+ C2H3O2-

Na+1 C2H3O2(-)

Na(+) C2H3O2(-1)

Na(+1) C2H3O2(1-)

Na(1+) C2H3O2-1

Sodium ion(+1) Acetate ion(-1)

NAION Acetate ion (-1)

Sodium ion ACETATEION

Natrium ion

Natrium ion(+1)


to do it

Create a new Lab Analysis Entry by clicking on the Global Icon and selecting Add Water Analysis

Enter the following Brine Analysis into the screen that opens Cations Na+ 10,000 mg/l Ca+2 500 Mg+2 1,200 Sr+2 200 Ba+2 5 Fe+2 5 Anions Cl- 19,000 mg/l SO4

-2 2,700 B(OH)4

- 180 HCO3

- 145 AsO4

-3- 12 Formate- 20 Acetate- 50 Propanate- 25 Thiocyanate- 2 H4DTPA

- 56 pH 7.8 Density 1.013 TDS 36,500 mg/l

Select Add Reconcile on the right-side of the screen. A new window appears.

Click on the Specs button and review the Electroneutrality options

A new screen appears that looks like the following

If you cannot create the correct species, you can find it using the list. Type in the first two or three characters. Then click on the down arrow to the right of that input cell. When the list appears below the cell, it should be near or even on the species you need. If you see more than one name for the same component, select it. They are synonyms.

You will note that some of the names will change. The H4DTPA- ion changes to H4(C14H18N3O10)-, because the Names Manager is set to formula. You can change this by selecting from the menu, Tools>Names Manager>Display Name or OLI Tag.

LabAnalyzer will reconcile the charge imbalance and calculate the fluid properties.

.


Electroneutrality

Dominant Ion

The largest species concentration of the deficient charge is added

In this case Na+ ion was added since there is an excess of negative charge.

Proration

An equal percentage of all deficient species is added.

Na+, Cl-

Sodium is added when there is an excess of negative charge, chloride is added when there is an excess of positive charge.

User Choice

The user specifies the cation or anion required to balance the sample.

Since there is an excess of negative charge, only the cations are available for selection with this option. 708.915 mg/L of Ca+2 is needed to balance the sample.

Make Up Ion

The specified ion is either added or subtracted to balance the charge.

With the make-up ion option, either a cation or anion can be used to adjust the Electroneutrality. Since in this example, there is an excess of negative charge, selecting a cation has the same result as the User Choice option. In the figure above, chloride ion has been selected. Since there is an excess of negative charge, 1254.212 mg of Cl- must be removed.

Make sure the Type of Balance button is set to Na/Cl and the click the OK button.

Exit the screen and return to the main worksheet

Click on the Auto NaOH/HCl button within the Reconcile pH area

Calculate

The Summary box is now updated with the current Electroneutrality


Review the Summary section

Click on the Report Tab and review the Scale Tendencies (about one-third the way down)

According to the calculation, 813 mg/l Na is needed to balance charge

In addition, 12.3 mg/l (0.34 mol/l) HCl is needed to fix the pH at 7.8

Lastly, some solids precipitated during the titration

In order to see what solids formed, we will review the Report

Three solids are calculated to precipitate (Their scale tendency =1.0), one of which is CaCO3. Since CaCO3 removal is removal of alkalinity, then the pH would naturally decrease. It is now the decision of the analyst to decide if this solid truly existed in the solution during the experiments. It is reasonable for this solid to not form, i.e., remain metastable, If that is the case, then we may remove the solids from the calculation, and allow the carbonate to remain in solution. We can review the species list and see how much carbonate mass was removed from solution.


Scroll down the report to the Species Output (True Species) section

Click on the Customize button in the upper right corner.

Click on the Species Output entry within the Category field

Next, select the Options tab

There is a Row Display field with an option: Only rows where any value is greater than..

Click on that radio button and enter the value 5.


From the menu, click on Chemistry>Model Options, and then click on the Phases tab.

Remove the check from the Solids entry within the Include Phases field

Make sure that the Calculate Scale Tendencies box is checked


Re-Calculate by pressing the F9 key

The Species output list is extensive, there are over 100 entries. We can reduce the list size by adding a filter located in the Customize window. Lets cut off the list a 1ppb. The new window contains formatting features that add or remove specific report sections and to also add/remove specific components within each section.

We will focus on the Species Output section of the Report

The 5 value correlates with the units chosen. For the ppm Aqueous, it is 5ppm, so any value greater than this will appear. The list length is reduced by 75%.

Solids mass is in the far right row. SrSO4 solids are 338 mg, followed by 127 mg CaCO3 and 8.4 mg BaSO4. The 127 mg (or 1.27 mmol/l) CaCO3 is equivalent of 2.54 mmol/l carbonate alkalinity. This is much more than the 0.34 mmol/l HCl added to increase pH. Thus, the CaCO3 precipitation had a greater impact on final pH then the HCl. If we re-reconcile this fluid with these solids still dissolved, we can see what the pH initially was just prior to precipitation.

(You will notice that BaSO4 is on the list, but only has a value of 3e-3 ppm, lower than this filter. This is because the solid phase is 8 mg, which exceeds the filter value for the solid phase. Therefore it also appears.)


Scroll down to the Scaling Tendencies section.

Review the top four entries

Return to the Reconciliation Tab and review the Summary section. How much NaOH was added?

Turn off the pH reconciliation

Recalculate

From the menu, click on Chemistry>Model Options, Phases.

Turn the solids back on


Calculate

Review the pH

Two sulfate and two carbonate solids are supersaturated, with BaSO4 having the greatest supersaturation. When we ran the calculation, only three solids precipitated. No SrCO3 solid formed, despite its supersaturation. This is because of competing ion effect among the four potential phases.

Instead of adding 12 mg/l HCl, 58 mg/l HCl is needed. This difference represents the impact of CaCO3 precipitation on overall pH.

Lastly, lets see what the pH is without reconciling.

The calculated pH is 8.9, much higher than the 7.8 recorded. This is a big difference and adds to the uncertainty.

There is one final calculation option; the pH when solids are turned on. Lets look at that calculation before we make a conclusion

The pH is 7.94, close to the measured value. This value is close enough to the measured pH to keep. Thus, we can probably use the system as-is, and not add any HCl. The pH will be off slightly, but with this approach, we are not changing any chemistry


Follow-up example In efforts to reinforce the above case, we will run this example again using a few different water analyses. The first one is an Arabian Gulf seawater. The other is a groundwater with unique composition. Run both cases, and perform two reconciliations, a basic equilibrium and a pH reconciliation. Note the amount of additive required to achieve the set pH and also note the solids content in each of the reconciliation calculations.

Name Arabian Gulf seawater 6,000 m well

Units Set WaterAnalysis Concentration

WaterAnalysis Concentration

Names Style Formula Formula

tricks of the trade

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