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PhysPack

User Guide

PhysPack User Guide

ii

NOTICE

The information in this document is subject to change without notice and should not be construed

as a commitment by ABB. ABB assumes no responsibility for any errors that may appear in this

document.

In no event shall ABB be liable for direct, indirect, special, incidental or consequential damages of

any nature or kind arising from the use of this document, nor shall ABB be liable for incidental or

consequential damages arising from use of any software or hardware described in this document.

This document and parts thereof must not be reproduced or copied without written permission from

ABB, and the contents thereof must not be imparted to a third party nor used for any unauthorized

purpose.

The software described in this document is furnished under a license and may be used, copied, or

disclosed only in accordance with the terms of such license.

TRADEMARKS

Microsoft, Windows and Excel are either registered trademarks or trademarks of Microsoft

Corporation in the United States and/or other countries. All other trademarks are the property of

their respective owners.

COPYRIGHT

Copyright © 2001-2012 ABB Limited. All Rights Reserved.

Document: PhysPack User Guide

Revision: 1.1

Published: October 2012

Software: PhysPack

Version: 4.2.0

SUPPORT INFORMATION

This program is developed, maintained and supported by PEL Support Services, ABB. We run a

Hotline telephone and email service to answer any queries about PhysPack.

Please let us have any suggestions on how you feel we could improve PhysPack. You can contact

us by any of the following routes:

By Telephone: +44 (0)1925 74 1126 By Post: PEL Support Services

ABB Limited.

Daresbury Park

Daresbury

Warrington

Cheshire WA4 4BT

United Kingdom.

By Fax: +44 (0)1925 74 1265

By email: [email protected]

iii

Contents

Preface ........................................................................................................................ 1

About this guide ...................................................................................................... 1 Who should read this guide ............................................................................. 1 What is in this guide ........................................................................................ 1 How this guide is structured ............................................................................ 1 Conventions .................................................................................................... 2

Chapter 1 – Introduction ...................................................................................... 3

What’s new .............................................................................................................. 3 Overview of PEL ..................................................................................................... 4

Chapter 2 – Getting started ................................................................................ 5

Starting PhysPack ................................................................................................... 5 Quitting PhysPack ................................................................................................... 5 User interface .......................................................................................................... 6 User assistance....................................................................................................... 6

Online help ...................................................................................................... 6 Online documentation ..................................................................................... 7 PEL Support Services ..................................................................................... 7

Chapter 3 – PhysPack Quick Tour .................................................................. 9

Part 1 – Components and aqueous solutions ......................................................... 9 The first 30 seconds … ................................................................................... 9 The next 30 seconds … ................................................................................ 10

Part 2 – Mixtures ................................................................................................... 11

Chapter 4 – Simple calculations..................................................................... 15

Calculating a pure component .............................................................................. 15 Selecting a pure component ......................................................................... 15 Viewing constant properties .......................................................................... 16 Viewing the calculated results ....................................................................... 17

Calculating an aqueous solution ........................................................................... 18 Selecting an aqueous solution ...................................................................... 18 Viewing constant properties .......................................................................... 19 Viewing the calculated results ....................................................................... 19

Changing the properties in the calculation ............................................................ 20 Specifying conditions for the calculation ............................................................... 20

Specifying conditions for a pure component ................................................. 21 Specifying conditions for an aqueous solution .............................................. 23

Changing the units for the calculation ................................................................... 24 Selecting molar or mass units ....................................................................... 25 Creating your own set of units ....................................................................... 25

Chapter 5 – Handling simple results ............................................................ 27

Viewing results as a graph .................................................................................... 27 Viewing a graph of the results ....................................................................... 28 Viewing the current graph ............................................................................. 28

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Adding selected results to the current graph ................................................ 29 Removing selected results from the current graph ....................................... 29

Printing your results .............................................................................................. 30 Printing all the results .................................................................................... 30 Printing selected results ................................................................................ 31

Saving your results ............................................................................................... 32 Saving the results as an Excel worksheet..................................................... 32 Copying the results to the clipboard .............................................................. 32 Copying selected results to the clipboard ..................................................... 32

Saving constants data ........................................................................................... 32

Chapter 6 – Advanced calculations .............................................................. 35

Calculating a mixture ............................................................................................ 35 Specifying the VLE method ........................................................................... 37 Specifying the LLE method ........................................................................... 39 Specifying the SLE method ........................................................................... 39 Describing the model ..................................................................................... 39 Saving the current stream ............................................................................. 39

Changing the properties in the calculation ............................................................ 40 Changing the units for the calculation ................................................................... 40 Specifying type and conditions for the calculation ................................................ 41

Specifying the type of calculation .................................................................. 41 Specifying a VL Equilibrium calculation ........................................................ 42 Specifying a Nonequilibrium calculation ........................................................ 46 Specifying a VL Phase Envelope calculation ................................................ 47 Specifying a Binary (non-equilibrium) calculation ......................................... 48 Specifying a Binary (VL Equilibrium) calculation ........................................... 49 Specifying a VLL Equilibrium calculation ...................................................... 51 Specifying an LL Equilibrium calculation ....................................................... 52 Specifying an SL Equilibrium calculation ...................................................... 53 Specifying a VL Mass Flux calculation .......................................................... 54

Viewing results for a mixture ................................................................................. 55 Showing phase data for a mixture ........................................................................ 56

Saving a phase as the feed stream ............................................................... 57 Selecting the key component for relative volatility ........................................ 57

Copying phase data .............................................................................................. 57 Copying the phase data to the clipboard ....................................................... 57 Copy selected phase data to the clipboard ................................................... 57

Saving all constants data ...................................................................................... 58 Calculation failures ................................................................................................ 58

Chapter 7 – Saving PhysPack data ............................................................... 59

Managing calculations files ................................................................................... 59 Saving a calculation file ................................................................................. 59 Opening a calculation file .............................................................................. 59

Managing physical properties files ........................................................................ 59 Saving a physical properties file .................................................................... 60 Opening a physical properties file ................................................................. 60

Quick reference ..................................................................................................... 61

Revision history .................................................................................................... 63

Glossary ................................................................................................................... 65

Index ........................................................................................................................... 67

1

Preface

Welcome to PhysPack, the tool for calculating and analysing the physical properties of

mixtures, pure components and aqueous solutions.

About this guide This guide is designed to assist you in becoming quickly familiar with the capabilities

of PhysPack, its interface and how the program is used.

Who should read this guide

This guide is written for users of PhysPack to help you take full advantage of its

calculation tools. If you are new to this product, we recommend that you first read The

60 Second Guide to PhysPack (Parts 1 and 2).

The guide assumes you are familiar with the Windows operating system. If you are

new to Windows, you can find help, tutorials and support information by clicking

Start > Help and Support.

What is in this guide

The guide contains descriptions and step-by-step instructions for all the tasks involved

in using PhysPack.

How this guide is structured

The chapters are organised as follows:

1. Introduction Introduces the product, outlining the main

features.

2. Getting started Shows how to start PhysPack, introducing the

user interface for the application.

3. PhysPack Quick Tour Tutorial for a typical session using PhysPack,

emphasising the commonly used features.

4. Simple calculations Shows how to run simple calculations for

pure components and aqueous solutions.

5. Handling simple results Shows how to handle results for simple

calculations.

6. Advanced calculations Shows how to set up calculations for

mixtures.

7. Saving PhysPack data Shows how to save calculation and physical

properties data so that it can be used in other

PEL applications.

PhysPack User Guide

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The guide also includes a quick reference section and a glossary.

Conventions

The following typographical conventions are used in this guide:

Convention Description

Bold To help with procedures, items that you click, select, or view may appear with the bold format (buttons, options, and window titles, for example).

Italic Proper names (software products, for example) and titles appear in the italic format.

Monospace Represents any text that appears on the computer screen or text that you should type. It is also used for filenames, functions, and examples.

Monospace

oblique Represents variable text where you would type in a specific value.

> The chevron indicates a menu option in a procedure. For example, click File > Open, means “on the File menu, click Open.”

3

Chapter 1 – Introduction

PhysPack is an easy-to-use database of physical properties, combined with a powerful

calculation engine suitable for both expert and less experienced users. It simplifies

chemical process design by enabling you to generate physical property data,

investigate them, and then transfer them to other PEL applications

You can quickly and easily obtain a diverse range of information both numerically and

graphically for pure components, aqueous solutions, or mixtures, for both single phase

or multiphase equilibrium and across a full range of temperatures and pressures.

Calculations for pure components

For pure components, simply select any one of the 18,000 components on the PEL

physical properties databank and PhysPack will instantly display the constant

properties (critical temperature, dipole moment, etc.), together with the liquid, vapour,

and solid properties over a range of temperatures and pressures. You can tailor the

output to your own requirements by specifying different ranges and different units of

dimension.

Calculations for aqueous solutions

The same applies for aqueous solutions. Simply select the solution, enter the

concentration, and PhysPack will display the results in the same format as for pure

compounds above. Specify a range of concentrations and see the effect this has on

different properties over a range of temperatures.

Calculations for mixtures

Mixtures are where the power of PhysPack really comes to the fore. Select the

compounds and specify their composition in either mass or molar units - you can

choose whichever you prefer and PhysPack will automatically generate the others.

Next, you can either choose from over 50 state-of-the-art methods to model the vapour

liquid equilibrium or you can let PhysPack choose the most appropriate one for you

using the built-in wizard. Then it's on to the type of calculation you wish to perform.

There are dozens to choose from - phase envelopes, binary plots, isothermal,

isenthalpic, isentropic, isochoric flashes to name just a few. The results are displayed

in an easy-to-read spreadsheet complete with quality assurance data for each point

calculated and phase composition data for each of the components.

What’s new This latest version of PhysPack (version 4.2.0) adds a new calculation type for

mixtures. The VL Mass Flux calculation lets you calculate the mass flux for an

isentropic nozzle flow based upon the calculation methods described in API Standard

520 Part 1. See “Specifying the type of calculation” on page 41.

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Overview of PEL PEL is a collection of tools to enable process engineers to carry out their day-to-day

tasks more quickly and reliably. The software includes purpose built programs to

generate datasheets, perform engineering calculations of liquid and / or gas flow,

investigate physical properties and create fault tree diagrams. Designed by engineers

for engineers, the tools are intuitive and easy to use. They can be used to work out

every day calculations, for troubleshooting issues such as bottlenecks, or when making

plant modifications. This low cost solution will enable engineers to design processes

more quickly and reliably with up-to-date and permanently available design data.

Benefits

Allows engineers to be more efficient and productive. With fewer manual

calculations to do, tasks are carried out quicker;

Improves QA and standardises procedures, through everyone using same set of

data and calculations;

Human errors in calculations are reduced;

Improves production as bottlenecks can be identified quickly so a solution can be

sought;

Allows operators to get the best out of their existing assets by carrying out

modifications rather than designing new ones.

5

Chapter 2 – Getting started

This chapter shows you how to start PhysPack and introduces the user interface for the

application.

Starting PhysPack The most common way of starting PhysPack is from the Windows Start menu, but you

can also run it from a desktop shortcut.

To start PhysPack from the Start menu:

Click Start > All Programs > PEL > PhysPack.

If using the classic Start menu or earlier versions of Windows, click Start >

Programs...

The PhysPack application opens.

Quitting PhysPack

To quit PhysPack:

Do one of:

On the File menu, click Exit.

Click the Close (X) button.

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User interface Once you have started PhysPack, you see the following, or similar, user interface.

The following main features are apparent:

Menu bar. Shows the command menus for accessing various features of the

application.

Components tab. Specifies the components to be examined. If you are modelling a

mixture, you specify its composition here.

Properties tab. Specifies the properties to be calculated and displayed.

Units tab. Specifies the units of measurement for the calculations.

Specification tab. Specifies the type and conditions for the calculation.

User assistance PhysPack has the following forms of user assistance:

Online help

Online documentation

PEL Support Services

Online help

PhysPack has an integrated online help system, which provides clear reference

information and step-by-step instructions for tasks.

To open the help system:

On the Help menu, click User Guide.

The help opens in a separate window.

Chapter 2 – Getting started

7

Online documentation

Documentation is provided for PEL products on the website. The documents are

provided as PDF files for you to download and print. These include:

60 second guides

Online user guides

PEL Support Services

This program is developed, maintained and supported by PEL Support Services, ABB.

We run a Hotline telephone and email service to answer any queries about PhysPack.

Please let us have any suggestions on how you feel we could improve PhysPack. You

can contact us by any of the following routes:

By Telephone: +44 (0)1925 74 1126

By Fax: +44 (0)1925 74 1265

By email: [email protected]

By Post: PEL Support Services

ABB Limited.

Daresbury Park

Daresbury

Warrington

Cheshire WA4 4BT

United Kingdom.

9

Chapter 3 – PhysPack Quick Tour

This chapter provides tutorials to get you started with the application. The tutorial,

which is divided into two parts, is available separately in print form (or as a PDF file)

entitled 60 Second Guide.

Part 1 – Components and aqueous solutions

This short self-paced tutorial will show you how easy it is to use PhysPack and how

quickly you can calculate accurate physical properties.

The first 30 seconds …

Within 30 seconds from now you will have learned how to use PhysPack to access

physical property data for pure components – both the constant properties like critical

temperature, critical pressure and boiling point, and the liquid and vapour properties

over a range of pressures and temperatures. You will also have learnt how to display

the results graphically.

Okay, the clock starts now…

Starting PhysPack

1) Click Start > All Programs > PEL > PhysPack.

The main PhysPack window appears. There are 4 tabs across the top of the

window; the Components tab is selected by default. On this tab there are 3

options – Pure Component, Aqueous Solution, and Mixture; Pure Component is

the default.

The first thing we need to do is to select a component.

2) In the Search for Name box, type MET for methanol. All the components on the

databank beginning with MET are then listed below. Click Methanol and

PhysPack automatically switches to the Constants tab to display all the constant

properties for Methanol.

Next, let‟s view the liquid and vapour properties.

3) Click the Liquid tab.

All the liquid properties for Methanol over the temperature range 0 – 60°C at

1bara are automatically displayed. Notice at the bottom of the screen the Quality

Assurance panel displaying the validity of each calculated point value. Move the

cursor into the different cells to see their associated QA values.

4) Click the Vapour tab to view the vapour properties.

All the vapour properties for Methanol over the temperature range 70 – 100°C at

1 bara are automatically displayed again with their associated QA codes.

Notice that the liquid properties stopped at 60°C and the vapour ones started at

70°C.

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5) Click the Constants tab to check the boiling point.

Finally, let‟s plot a graph of saturated liquid vapour pressure v temperature

6) Click the Liquid tab. Scroll

across to the Liquid

Saturated Vapour Pressure

and then click the column

header to select that

column. Next right-click

and click Graph Selected

Results from the context

menu.

You should now see the

graph opposite…

7) Click the close (X) button to close the graph window.

The next 30 seconds …

Okay this time we‟re going to look at aqueous solutions and plot a graph of liquid

density v temperature at different concentrations – again all within 30 seconds!

8) Click the Components tab and select Aqueous Solution.

First, let‟s look at the properties of a 15% W/W solution of nitric acid?

9) Enter 15 in the %W/W box and then click Nitric Acid from the list of available

solutions.

Again PhysPack automatically switches to the Constants tab to display the

constant properties. Notice PhysPack reports the 2 concentrations it has used for

the interpolation of the results determined by combination of Nitric Acid – 10%

and 20%.

10) Click the Liquid tab to view the liquid properties.

And that‟s it – well not quite. Remember we wanted to plot the liquid density at

different concentrations. So we need to go to the Specification tab and set the

concentration ranges for the calculation.

11) Click the Specification tab and then select Range under the concentration panel.

Set the Start to 10%W/W, the Finish to 20%W/W, and the Step to 5%W/W.

Now all we need to do is

recalculate the results and

plot the graph

12) Click the Liquid tab to

display the new results over

the concentration range and

then click the column

header for Density to select

that column. Next right-

click and click Graph


11

Selected Results on the context menu.

You should now see the graph opposite…

13) Click the close (X) button to close the graph window.

That‟s it – and all within 60 seconds! Time now to try out Part 2 of the 60 Second

Guide to PhysPack and see how easy is it to do more complicated calculations

involving mixtures of components.

After you‟ve learned the basics it‟s time to read the rest of the PhysPack User Guide.

This will tell you more about all of the really useful features and options in the

program.

Part 2 – Mixtures

This short self-paced tutorial will show you how easy it is to use the new PhysPack

and how quickly you can calculate accurate physical properties.

Within 60 seconds from now you will have learned how to use PhysPack and

produced a graph of the phase envelope for a mixture of methane, ethane and propane.

Okay, the clock starts now…

Starting PhysPack

1) Click Start > All Programs > PEL > PhysPack.

The main PhysPack window appears. There are 4 tabs across the top of the

window; the Components tab is selected by default. On this tab there are 3

options – Pure Component, Aqueous Solution, and Mixture; Pure Component is

the default.

The first thing we need to do is add the components.

2) Select the Mixture option.

A new panel is displayed with several tabs – the default one being Feeds. This tab

is where we select the components we are interested in and specify their

compositions.

3) Click Add Component to display the Select Components from Databank

window.

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4) In the Search for Name box, type ME for methane. All the components on the

databank beginning with ME are then listed below. Scroll down the list, Click

METHANE and then click Add to Stream at the bottom of the window to add

methane to our stream. (Tip: you can also double-Click the name to add it to the

list) Next, delete ME from the Search box and type ET for ethane; double-Click

ethane in the list to add ethane to the stream. Repeat this for propane. Finally,

click Close to return to the Mixture panel.

Next we need to set the feed for each component – 50% methane, 40% ethane,

10% propane by mass fraction

5) Click the mass fraction column in the spreadsheet. Type 0.5 for methane, 0.4 for

ethane, and 0.1 for propane.

Notice that PhysPack automatically calculates the Mole, Mole Fraction, and

Mass.

Next, we need to check which method PhysPack has chosen to model the Vapour

Liquid Equilibrium.

6) Click the VLE tab.

You can see that the Peng Robinson (PR/PR) method has been automatically

selected for both the vapour and the liquid phases. This method is an Equation-of-

State and is very suitable for modelling hydrocarbons at high temperatures and

pressures. To find out more about VLE methods Click PhysProps Help on the

Help menu at the top of the screen. Then select Thermodynamic Models from the

Reference Guide.

Now on to specify the calculation type - we want a phase envelope calculation

7) Click the Specification tab at the top of the screen. Click the down-arrow on the

box for selecting the calculation type and select VL Phase Envelope.

That‟s all we need to specify. We‟re now ready to do the calculation and see the

results so …

8) Click the Stream tab at the top of the screen. After a few seconds PhysPack

presents the results in a spreadsheet. Move up and down using the scroll bar to

see the results and notice the Comments column which identifies the Maximum

Temperature, Maximum Pressure, and the Critical Point.

Fine, but we wanted a graph not a table so …

9) Click the column header for Stream Pressure; the column goes black to show it

has been selected. Now right-click the column and click Graph Selected

Results in the context menu. Hey Presto! - there‟s your graph just like the one on

the previous page. If you right-click the graph you can modify its appearance to

your heart‟s content as well as print it or copy it to another program. Finally, click

the X at the top right hand corner of the Graph window to return to the

spreadsheet.

Now let‟s go back and see what happens if we use a different VLE method?

10) Click the Components tab at the top of the screen. Clear the Allow automatic

selection of VLE Method check box then select the Redlich Kwong Soave

method called RKS(API)/RKS(API) in the list.

11) Switch back the Stream tab. Select the Stream Pressure column, right-mouse

click, and select Add Selected Results to the Current Graph on the context

menu. Both sets of results appear on the same graph so you can easily compare

the differences between the two methods.


13

And that‟s it. How‟s the time doing? Did you beat the clock? If you have, try

clicking on the Units tab and converting the Temperature from K to C and see

how easily different units can be used.

Now you‟ve learned the basics it‟s time to read the PhysPack User Guide. This will

tell you more about all of the really useful features and options in the program.

15

Chapter 4 – Simple calculations

PhysPack lets you run physical properties calculations for pure components, aqueous

solutions or mixtures.

This chapter shows you how to run simple calculations for pure components and

aqueous solutions, how to change the properties included in the results, how to specify

the conditions, such as temperature and pressure ranges, and how to change the units

for the results.

Calculating a pure component The process for running a PhysPack calculation for a pure component is very easy to

follow. The starting point is the Components tab with the Pure Component option

selected. This is the default view of the application when you start PhysPack.

Selecting a pure component

The first step in running a calculation is to select the component. The default (Pure

Component) option lets you select a single component (chemical compound) for using

in your calculation. Components can be selected from any of the physical properties

databanks. The PPDS databank is the most comprehensive: the other options are for

specific applications, such as petroleum distillation.

To select a pure component:

1) On the Components tab, click Pure Component. This is selected by default.

2) In the Search for Name text box enter part of the component name as a search

string. You can include a wildcard (*) to

3) In the Select Databank list, select which databank to search. The PPDS system is

selected by default.

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Components matching the search string appear in the Search Results list.

4) Scroll down the list as necessary and click the component you want.

PhysPack automatically switches to the Constants tab to display all the constant

properties for the component. See “Viewing constant properties” on page 16.

Viewing constant properties

As soon as you select a component the Constants tab appears. This shows constant

property values for the component. These include values such as the component‟s

various names, its boiling and melting points and its standard state.

The drop-down list at the top of the dialog lets you switch between components in a

mixture. For a single pure component only one item is in the list.

Notice that further tabs have appeared – typically Liquid and Vapour. These contain

the calculated results for each of the phases.


17

Viewing the calculated results

Physical properties for the single component are calculated for both liquid and vapour

phases over a range of temperatures and pressures. The calculated results appear in a

separate tab for each phase. In each phase the results show the physical properties

calculated at various temperatures and pressures. The first two columns define the

temperature and pressure ranges: the remaining column show the property values at

each temperature and pressure.

By default, the properties are calculated for temperatures between 0 and 100°C in

steps of 10° at a pressure of 1 bar. This can be changed on the Specification tab. For

more information, see “Changing the properties in the calculation” on page 20.

Also by default, only the Liquid and Vapour phases are modelled. You can extend this

by clearing a check box on the Specification tab. For information on this, see “Using

VLE modelling” on page 22.

To view the results:

Click the Liquid (or Vapour) tab.

Viewing quality assurance indicators

The bottom area of the tab shows various quality assurance indicators.

If you click any individual field, the four indicators show:

Validity. The validity of the calculation with respect to temperature.

Accuracy. The accuracy of the value, such as “< 1%”.

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Evaluation. The calculation method used, .such as “PPDS databank” or “Lee-Kesler

correction”.

Source. How the value was derived, such as. “Experimental” or “Calculated”.

Calculating an aqueous solution The process for running a PhysPack calculation for an aqueous solution is similar to

the default pure component calculation.

Selecting an aqueous solution

This option lets you select an aqueous solution for your calculation.

To select an aqueous solution:

1) On the Components tab, click Aqueous Solution.

2) In the %W/W field, enter the concentration of the solution.

3) Scroll down the Aqueous Components list as necessary and click the

component you want.

4) The Constants tab.

PhysPack opens the Constants tab to show the constant properties for the

aqueous component. See “Viewing constant properties” on page 19.


19

Viewing constant properties

As soon as you select an aqueous component the Constants tab appears. This shows

constant property values for the aqueous component. This much smaller list includes

values such as minimum and maximum concentrations and boiling and melting points.

Notice that a single further tab has appeared – for Liquid phase results.

Viewing the calculated results

The calculated results for an aqueous solution appear in a single liquid phase tab. The

vapour and solid phases are not modelled. The results show the physical properties at

various concentrations and temperatures. The first two columns define the

concentrations and temperature ranges: the remaining column show the property

values.

By default, the properties are calculated for temperatures between 0 and 100°C in

steps of 10° at the concentration entered on the Components tab.

To view the results:

Click the Liquid tab.

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Changing the properties in the calculation PhysPack contains a large number of properties that can be included in a calculation.

By default, all the properties are calculated. The Properties tab lets you limit which

physical properties are included.

For pure components this covers the three phases – liquid, vapour and solid. For

Aqueous solutions, only a single set of properties appears.

By default all the properties in each phase are selected. You can also compile your

own set of properties by selecting and/or clearing items from the selection as follows:

Click All to select all the properties for the phase

Click None to clear the selection

Drag though the list to select a group of properties

Ctrl+click to select or clear individual properties

Shift+click to select all the properties between the current and last selected items.

Tip If you want to include most of the properties in your calculations, click All and

then use Ctrl+click to clear the individual properties you don‟t want.

Specifying conditions for the calculation When you select a pure component or aqueous solution on the Component tab, results

are calculated automatically using the default conditions. The Specification tab lets

you specify new conditions, with results recalculated when you click a results tab.

The conditions for a calculation consist of two independent variables. These equate to

the first two columns in the results tables. Each variable can be specifed as either a list

(of one or more values) or a range of values. A range is delimited by start and finish

values, with the intermediate values set either by step size or by the number of points.

Each variable can have one or more values. If each variable has a single value the

physical properties are calculated for a single point (that is, the results tabs contains


21

just one row). If each variable has mutiple values, the number of points is the product

of the numbers of each variable.

Specifying conditions for a pure component

For a pure component calculation the independent variables are temperature and

pressure: either can be first. By default both variables are defined as a range.

To change the order of the variables:

In one of the variable list boxes, click the other option in the list.

The variables swap sides with all their underlying conditions.

To change the range of a variable:

1) Enter new start and finish values as required.

If the start value is greater than the finish value the results appear in descending

order.

2) Do one of:

Enter a new step value

Click No of Points and enter a new value. Then click Step to see the value

as a step difference.

To specify a variable as a list:

1) Click the List option.

The section changes to a single list pane.

2) Type the remaining values as required.

Using the condition variables in pairs

Usually if you specify multiple values for the two condition variables, the number of

points (and hence the number of rows in the results tabs) is a product of the two. If the

two variables have an equal number of (mutiple) values, PhysPack lets you consider

them as pairs. So, for example, if you have 11 values for pressure and 11 for

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22

temperature, your results can either have 121 rows (if the values are not paired) or 11

if they are.

To use condition values in pairs:

1) For each variable, arrange the values (in either Range or List format) so that the

number of points is equal.

2) A check box appears at the bottom of the tab.

3) Select the Use Condition values in pairs check box.

The results are calculated for the condition values as pairs.

To use all condition value combinations:

Clear the Use Condition values in pairs check box.

The results are recalculated with every combination of the condition values.

Using VLE modelling

By default, calculations for a pure component use VLE modelling. This assumes the

component can only exist in its liquid or vapour phase and so results are only

calculated for those two phases.

To model the component in all three phases:

Clear the Use VLE check box.

An extra Solid phase tab appears.

To use VLE modelling for the component:

Select the Use VLE check box.

The Solid phase tab disappears.


23

Specifying conditions for an aqueous solution

For an aqueous solution calculation the independent variables are concentration and

temperature: either can be first. By default, the concentration is defined as a list and

temperature as a range.

You can change the order of the variables, and you can change the range and specify

the number of points in each variable. If both variables have the same number of

points, an extra option lets you consider them in pairs. See “Using the condition

variables in pairs” on page 21.

To specify the calculation:

1) Specify the order and range/list of the variables as required. See “Specifying

conditions for a pure component” on page 21.

2) Click the Liquid tab to see the recalculated results.

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Changing the units for the calculation The Units tab lets you select the units for values that appear on the Constants, the

Specification and the results tabs. Three predefined set of units are provided:

Engineering units – the units most commonly used in the chemical process

industries. They are mostly SI units, but with a few variants, such as

Parameter SI unit Engineering unit

Temperature K (Kelvin) C (Celcius)

Pressure N/m2 bar

Dynamic viscosity N.s/m2 cP (centipoise)

Other units differ just by degree, such as mm for short length (instead of m).

SI units – the international system of units, the standard metric system

British units – standard UK (Imperial) or US units

Engineering units are the default set when you install PhysPack.You can set one of the

other predefined sets as the default or compile your own set.

To change the units to a predefined set:

1) Click the Units tab.

2) Click the button for the set you want to use, such as SI.

A prompt asks you if you want to select these units as the default so that the set is

loaded next time you start PhysPack.

3) Click Yes.

The selected set appears in the dialog.


25

Selecting molar or mass units

The Units tab lets you determine how properties such as specific heat, density and

entropy and enthalpy appear on both the constants tab and on the results tabs. They

can be shown as either a mass or molar quantity. For example, in engineering units

density is either in kg/m3 (mass units) or kmol/m

3 (molar units).

To show values in molar units:

On the Units tab, click Select Molar Units.

The affected values change on the Constants tab and on the results tabs.

To show values in mass units:

On the Units tab, click Select Mass Units.

The affected values change on the Constants tab and on the results tabs.

Creating your own set of units

The Units tab lets you compile your own set of units. You can save these changes to a

file and reload as you need. The units file is saved by default to the PEL/Apps folder

where PhysPack is installed. You can save the file elsewhere.

To create a new set of units:

1) On the Units tab, click the unit you want to change to select the cell in the table.

2) Right-click the cell and click one of the alternative units in the context menu.

3) Repeat for other units as required to complete your set.

4) Click Save units to file, enter a name for file (the default is UserUnits.uns),

browse to where you want to save the file (optional) and click Save.

To load an existing set of units:

1) On the Units tab, click Get units from file.

2) Browse to where the file is saved (if not the PEL/Apps folder) and click Open.

A prompt asks you if you want to select these units as the default so that the set is

loaded next time you start PhysPack.

3) Click Yes.

The selected set appears in the dialog.

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Chapter 5 – Handling simple results

The previous chapter, simple calculations” on page 15, showed you how to create

results for pure components or aqueous solutions, and then modify the results by

changing the properties, conditions and/or units. This chapter shows you the various

ways to handle these results – viewing selected results as a graph, printing the results

tables and saving the data as an Excel spreadsheet.

Viewing results as a graph Once you have created the results for a pure component or an aqueous solution and

modified the results as necessary by changing the properties, conditions and/or units,

you can view a plot of one or more columns of the results as a graph.

The appearance of a graph will depend on the how many properties you select to

appear on the graph and the range of the condition variables. For example, using the

default settings for a pure component and selecting one component would open a

graph with a single plotted line.

You can select the columns for your graph in any of the following ways:

Click the column header to select a single column

Ctrl+click to select further columns

Drag though the headers to select a group of columns

Click then Shift+click to select a group of adjacent columns.

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Multiple value graphs

If you select more than one column of property values, the graph will show multiple

lines in different colours with a key shown below. You will also see multiple lines if

you change the conditions to show more than one point for the pressure variable.

Notice that multiple columns of values appear as separate lines: multiple pressures can

sometimes appear as a continuation of the same line.

Various commands on the context (right-click) menu let you print the graph or copy

the image to the clipboard, so that you can paste the image into a report. You can also

change the formatting of the axes, title and legends or even the chart type, if you wish.

Viewing a graph of the results

To view results as a graph:

1) Select one or more columns.

2) Do one of:

On the Results menu click Graph Select Results.

Right-click the table and click Graph.

The graph opens in a pop-up window.

Viewing the current graph

After you close a graph you can open it again (as long as you haven‟t created another

one)

To view the current graph:

Do one of:

On the Results menu click Display Current Graph.

Right-click the table and click Display Current Graph.

The graph reopens in a pop-up window.


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Adding selected results to the current graph

This feature lets you add extra column of property values to the graph. The extra

values will appear on the graph as one or more lines.

Tip For pure components, you can use this feature to show a single property across

each of the phases.

To add selected results to the current graph:

1) Switch to the required results tab, if applicable.

2) Select the columns you want to add to the graph.

3) Do one of:

On the Results menu click Add Selected Results to Current Graph.

Right-click the table and click Add Selected Results to Current Graph.

The redrawn graph opens in a pop-up window.

Removing selected results from the current graph

To remove selected results from the current graph:

1) Switch to the required results tab, if applicable.

2) Select the columns you want to remove from the graph.

3) Do one of:

On the Results menu click Remove Selected Results from Current

Graph.

Right-click the table and click Remove Selected Results from Current

Graph.

The graph reopens in a pop-up window.

To print the graph:

1) Right-click the graph background and click Print.

The Print dialog opens.

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2) The Print Setup tab lets you select a printer. Your default is already selected.

Click the tab to select a different printer.

3) The Page Setup tab lets you fit the graph to the page and set margins. Click the

tab if you need to change the settings.

4) On the Print tab, change the layout option, if required, and click Print.

Printing your results This feature lets you print the table of results on the current results tab, or a selection

of rows from the table, to your local or network printer.

You can select the rows for printing in any of the following ways:

Click a cell in the first two columns to select a single row

Ctrl+click to select further rows

Drag though the first two columns to select a group of rows

Click then Shift+click to select a group of adjacent rows.

Printing all the results

This will print the table of results on the current tab.

To print all the results:

1) Do one of:

On the Results menu click Print Results as a Table > Print All Results.

Right-click the table and click Print Results as a Table > Print All Resuts.

The Page Setup dialog opens.


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2) The dialog lets you fit the table onto one or more pages, set the margins and the

various print options. Change as required and then click OK.

3) Choose your printer and click OK.

The results are sent to the printer.

Printing selected results

To print selected results:

1) Select the rows you want to print.

2) Do one of:

On the Results menu click Print Results as a Table > Print Selected

Results.

Right-click the table and click Print Results as a Table > Print Selected

Resuts.

The Page Setup dialog opens.

3) Change the various options as required and then click OK.

4) Choose your printer and click OK.

The results are sent to the printer.

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Saving your results These features let you save the table of results on the current tab to a Microsoft Excel

file. You can also copy the results table, or a selection from the table, to the clipboard.

Saving the results as an Excel worksheet

To save the results as an Excel worksheet:

1) Do one of:

On the Results menu click Save Results as an Excel Worksheet.

Right-click the table and click Save Results as an Excel Worksheet.

2) Browse to where you want to save the file, rename the file if required and then

click Save.

Copying the results to the clipboard

To copy the results to the clipboard:

Do one of:

On the Results menu click Copy Results to Clipboard.

Right-click the table and click Copy Results to Clipboard.

The whole table, including the column headers is copied to the clipboard as a tab

separated list. You can then paste the list into a Windows application.

Copying selected results to the clipboard

To copy the results to the clipboard:

1) Select the required rows, columns or cells you want to copy.

2) Do one of:

On the Results menu click Copy.

Right-click the table and click Copy.

Press Ctrl+C.

The selected values (without column headers) are copied to the clipboard as a tab


Saving constants data This feature lets you save the data on the Constants tab as a report file. The file is in

plain text format.

To save the constants data to a report:

1) Click the Constants tab

2) On the Results menu click Save report for current component.


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click Save.

The data on the constants tab is saved as a plain text report file (.rep).

You can open the saved report file in any Windows application that handles text files,

such as Notepad.

Tip If you want to print the file set the page orientation to “Landscape”.

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Chapter 6 – Advanced calculations

The chapter on simple calculations covers the basic features of PhysPack in creating

calculations for pure components and aqueous solutions. This chapter shows you how

to set up physical properties calculations for mixtures.

Calculating a mixture This option opens a multiple tab that lets you define a mixture for using in your

calculation. The Feeds tab lets you define the composition of the mixture. Further

tabs let you define the thermodynamic models used for defining vapour-liquid

equilibrium (for a liquid/gas two phase fluid), liquid-liquid equilibrium (for a two-

liquid mixture) and solid-liquid equilibrium.

The Feeds tab provides a stream composition worksheet, which lets you define a

name and the constituent parts of the process stream. Whenever you open the dialog

the table always contains the last values used. This lets you run multiple calculations

on the same fluid without having to specify or load the stream each time.

You can add components to the stream and then specify the molar and/or mass

quantities in the stream.

To define a mixture:

1) On the Components tab, click Mixture.

2) In the Stream name field, enter a name for the stream.

3) Add the various components, as described in “Adding Components” on page 36.

As soon as you add the first component, the Constants tab, a Streams tab and

the phase results tabs open in the background.

The molecular weight of each component and the average molecular weight for

the stream appear in the Mol Wt column on the worksheet.

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If you want to remove a component from the worksheet, click the component

name to select the whole row, right-click the row and click Remove Selected

Components.

4) Specify the quantities or relative amounts of each component in one of the other

four columns:

Molar – the molar quantity of each component.

Mol Fraction –the mole fraction of each component.

Mass – the mass of each component

Mass Fraction – the mass fraction of each component

The worksheet calculates the values in the other three columns and the totals. If

you enter fraction values, you must ensure that they total to 1.

If you need to restart the calculation, right-click the worksheet and click Zero All

Cells.

5) Click OK.

To clear all components:

On the Feeds tab, click Clear Worksheet.

All of the components are removed from the table.

Adding Components

To add a component:

1) On the Feeds tab, click Add Component.

The Select Components dialog opens.

2) Click the Databank in the list and start typing a search string.

Matching entries appear in the Search Results pane as you type.

3) Select the component you want and click Add to Stream.

4) Add all the components you want and then click Close.


37

Specifying the VLE method

The VLE tab lets you specify the thermodynamic model used to calculate the vapour-

liquid equilibrium and the physical properties of the stream.

VLE Method. You can either select the method in the list, or let the program choose

based on the components in the stream. The chosen method is used to evaluate the

phase equilibrium, i.e. the number of phases, the phase split and the equilibrium

compositions of the individual components.

Calculation Mode. Select „Accurate‟ or „Consistent‟ as the method for calculating

each of these groups of properties.

In Consistent mode, the thermodynamic model is used to evaluate the properties.

This gives a consistent approach, but the results for some properties may be

significantly in error, e.g. 20-30% in liquid density values. Note that only certain

properties can be evaluated from the model. Fugacity, density, compressibility,

enthalpy, entropy and Gibbs free energy are evaluated in this manner. Other

properties such as heat capacity, viscosity and thermal conductivity are evaluated from

the databank methods irrespective of the accurate/consistent setting.

In Accurate mode, the properties are evaluated where possible from the stored

coefficients in the pure component databank. For the vapour phase, the Lee-Kesler

method is used for pressure corrections.

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Binary Interaction Parameters (BIPs)

Some thermodynamic VLE models can account for interactions between components

in the mixture which cause deviations from ideal behaviour. If such a model is used,

you can view and change the BIPs.

The spreadsheet shows which pair of components is being considered. In some cases

the Component 1 – Component 2 interaction parameter is the same as the Component

2 – Component 1 interaction parameter (symmetric) so only one cell for the pairing is

active. In the example above, the parameters are different (asymmetric).

Row / Col. Identifies the first and second components being considered.

Vapour / Liquid. Identifies which phase and thermodynamic model is being

considered.

A / Alpha. Shows and lets you edit the temperature dependent coefficients for the

BIP A or Alpha value.

P/T. Shows and lets you edit the Lower, Reference and Upper pressure and

temperature values for the BIPs.

Source. Shows and lets you edit a string identifying the source for the BIP data.

Equation Code. Shows and lets you edit a numeric value (0, 1, 2) which specifies

the order of the temperature dependence of the BIP parameter, e.g.

0: A = a0

1: A = a0 + a1T

2: A = a0 + a1T + a2T2

Reference. Shows and lets you edit a numeric code identifying a reference code for

the BIP data.


39

Specifying the LLE method

The LLE tab lets you specify the thermodynamic model used to calculate the liquid-

liquid equilibrium of the stream.

LLE Method. You can select the method in the list.

For information on choosing an equilibrium method, click Help > PhysProps Help to

browse the PPDS Reference Guide.

Specifying the SLE method

The SLE tab lets you specify the thermodynamic model used to calculate the solid-

liquid equilibrium of the stream.

SLE Method. You can select the method in the list.

For information on choosing an equilibrium method, click Help > PhysProps Help to

browse the PPDS Reference Guide.

Describing the model

The Remarks tab lets you enter a description of the stream being modelled.

The information is entered as plain text.

Saving the current stream

The Files tab lets you save the current stream on the Feeds tab as a file or recall a

previously saved stream file. The saved file (.psm) contains the components and the

calculated molar/mass quantities, fractions and totals.

To save the current stream:

1) Click the Files tab.

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2) Click Save.

3) Change the file name and location, if required, and click Save.

To open a saved stream:

1) Click the Files tab.

2) Click Open.

3) Browse to select the stream file and click Open.

The recalled stream now appears on the Feeds tab.

Changing the properties in the calculation As with simple calculations, the Properties tab lets you limit which physical

properties are included in the calculation. For a mixture this covers the three phases –

liquid, vapour and solid – the same as for pure components.

By default all the properties in each phase are selected. You can also compile your

own set of properties by selecting and/or clearing items from the selection as follows:

Click All to select all the properties for the phase

Click None to clear the selection

Drag though the list to select a group of properties

Ctrl+click to select or clear individual properties

Shift+click to select all the properties between the current and last selected items.

Changing the units for the calculation The Units tab lets you select the units for values that appear on the Constants, the

Specification and the results tabs. This is the same as for simple calculations. See

“Changing the units for the calculation” on page 24.


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Specifying type and conditions for the calculation For simple calculations the variables on the the Specification tab were restricted to

particular options – temperature and pressure (for pure components) or concentration

and temperature (aqueous solutions). For pure components, you could also change the

type of calculation by switching VLE modelling on or off.

For a mixture, you can select from a number of different calculation types. A wider

selection of conditions is provided which is dependent on the calculation type.

Specifying the type of calculation

Nonequilibrium. Calculates mixture properties but with no phase equilibrium.

The same composition is used for both phases, and no stream properties are

calculated.

VL Equilibrium. Calculates the vapour-liquid phase equilibrium first, i.e. the

quantity and composition of both phases, and then calculates properties for each phase

and the stream as a whole.

This is the most common type of calculation.

VL Phase Envelope. Calculates the boundaries (temperature and pressure) of the

two phase region.

Binary (Nonequilibrium). Calculates binary mixture properties for a range of

compositions.

Binary (VL Equilibrium). Calculates the binary x-y diagram for two components

with phase equilibrium.

VLL Equilibrium. Calculates the vapour-liquid-liquid phase equilibrium first, i.e. the

quantity and composition of three phases, and then calculates properties for each

phase and the stream as a whole.

LL Equilibrium. Calculates the liquid-liquid phase equilibrium first, i.e. the



SL Equilibrium. Calculates the solid-liquid phase equilibrium first, i.e. the quantity

and composition of both phases, and then calculates properties for each phase and the

stream as a whole.

VL Mass Flux. Calculates the mass flux (as per API 520) for isentropic nozzle flow,

i.e. for a specified inlet temperature and pressure, calculates the properties for

isentropic change to a series of lower pressures.

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Specifying a VL Equilibrium calculation

This type of calculation calculates the vapour-liquid phase equilibrium first, i.e. the


and the stream as a whole. This is the most common type of calculation.

For this calculation type, you can select each of the independent variables from a list

of options. Some options, such as temperature and pressure, appear in each list: others,

such as bubble point are only available in one list. The options are:

First variable Second variable

Pressure / Temperature Temperature /, Pressure

Enthalpy

Entropy

Molar Vapour Fraction

Mass Vapour Fraction

Specific Volume

Bubble Point (i.e. Vapour Fraction = 0)

Dew Point (i.e. Vapour Fraction = 1)

Enthalpy / Entropy Temperature

Pressure

Entropy / Enthalpy

Internal Energy Specific Volume

Specific Volume Temperature

Pressure

Internal Energy

The program does not let you select the same variable in both lists.


1) In the list of calculation types, click VL Equilibrium. This is set by default.

2) Select each of the two variables in turn.

The options in the second list depend on your choice for the first variable.

3) Specify a range for the variables or a list as required. See “Specifying conditions

for a pure component” on page 21.


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4) Click any of the results tabs to start calculating results for the stream as a whole,

or for the liquid or vapour phases.

Enthalpy / Entropy / Specific Volume calculations

In PPDS, Isenthalpic, Isentropic, and Isochoric calculations are always carried out in

„consistent‟ mode; that is, an isothermal (fixed pressure and temperature) calculation

is carried out iteratively until the specified enthalpy / entropy / volume is achieved,

using the thermodynamic model for the flash calculation to evaluate the appropriate

physical property.

If you have selected „accurate‟ calculation mode on the VLE tab of the stream builder,

then the final results are evaluated from the stored coefficients in the pure component

databank and this can mean that the calculated values are not at your specified points.

To overcome this, an Iterate check box appears until the variable list box. If you have

selected „consistent‟ mode, the check box does not appear.

If you select the check box, PhysPack will carry out the calculation iteratively until the

final calculated values are at the specified conditions.

Total amount

By default Enthalpy, Entropy and Volume values are in terms of the quantity of

material on either a mass or molar basis; for example enthalpy in kJ/kmol.

Alternatively, if you select the Use “Total” amount check box these values become

total quantities for the stream, with the units changing to kJ.

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Bubble point / dew point calculations

Within VL equilibrium calculation, you can calculate the bubble point or dew point at

varying pressures or temperatures.


1) In the list of calculation types, click VL Equilibrium.

2) Select the first variable as Pressure or Temperature.

3) Specify the range or list as required. See “Specifying conditions for a pure

component” on page 21.

4) Select the second variable as Bubble Point (or Dew Point).

There are no parameters for the second variable.

5) Click one of the results tabs. Bubble point (or dew point) appears as the first

result column.


45

Isenthalpic / Isentropic / Isochoric calculations

Modelling some processes is a two-stage calculation; for example, calculating the

temperature after an isenthalpic change from an initial temperature and pressure to a

new pressure requires you to calculate the enthalpy at the initial state, then calculate

the temperature at the new pressure at the same enthalpy. This feature lets you do this

as a single step.


1) In the list of calculation types, click VL Equilibrium.

2) Select the two variables as Pressure and Temperature. This can be either way

around.

3) Select the Isenthalpic / Isentropic / Isochoric check box.

The dialog changes to show 3 sections for upstream pressure, then upstream and

downstream temperature.

If the temperature variable is first, the sections are upstream temperature, then

upstream and downstream pressure.

4) Select the type of calculation:

Isenthalpic (constant enthalpy),

Isentropic (constant entropy),

Isochoric (constant specific volume).

5) Specify range of the variables or list as required. See “Specifying conditions for a

pure component” on page 21.



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Specifying a Nonequilibrium calculation

This type of calculation calculates mixture properties but with no phase equilibrium.

The same composition is used for both phases, and no stream properties are

calculated.

As with a pure calculation, the independent variables are temperature and pressure:

either can be first. By default both variables are defined as a range.






1) In the list of calculation types, click Nonequilibrium.


3) Specify the range or list for each variable as required. See “Specifying conditions


4) Click either of the results tabs to start calculating results for the liquid and vapour

phases.


47

Specifying a VL Phase Envelope calculation

This type of calculation calculates the boundaries (temperature and pressure) of the

two phase region. It calculates the temperature and pressures at a specified vapour

fraction and temperature/pressure. It continues along the phase envelope at the same

vapour fraction to the critical point and then moves away from the critical point,

calculating for a vapour fraction equal to 1 minus the specified value.

Note The stream must contain at least two components before a phase envelope

calculation can be carried out.


1) In the list of calculation types, click VL Phase Envelope.

2) Do one of:

Enter the start temperature.

Click Start Pressure and enter the pressure.

3) Enter the vapour fraction.

This is a value in the range 0.0 to 1.0 which specifies the mole fraction of the

stream in the vapour phase for the first part of the envelope. If this is zero then

the calculation follows the bubble line up to the critical point and then the dew

line moving away from the critical point. If the value is 1.0 then the calculation

is performed the other way round.

4) Enter the number of points to calculate along the envelope.

This is the maximum number of points – the actual number may be smaller, and

in any case will not exceed 500.



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Specifying a Binary (non-equilibrium) calculation

This type of calculation calculates binary mixture properties for a range of

compositions.

The independent variables are temperature and pressure: either can be first. The first

variable can be either a range or a list of values: the second is a single fixed value.

An additional Binary Calculation section and the centre section let you specify the

starting and finishing fractions for the first binary component in the stream.


1) In the list of calculation types, click Binary (Nonequilibrium).


3) Specify the range or list of the first variable as required. See “Specifying

conditions for a pure component” on page 21.

4) Enter a single fixed value for the second variable.

5) In the Binary Calculation section, click the appropriate option to specify whether

the composition is based upon a Mole Fraction or a Mass Fraction.

6) Also under Binary Calculation, specify which components in the mixture are to

be treated as the first and second components in a binary mixture. Any other

components in the original mixture are ignored.

7) In the centre section, specify the starting and finishing fractions for the first

component. The defaults are from 0 to 1.

8) Click either of the results tabs to start calculating results for the liquid and vapour

phases.


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Specifying a Binary (VL Equilibrium) calculation

This type of calculation calculates the binary x-y diagram for two components with

phase equilibrium.

For this calculation type, you can select each of the independent variables from a list

of options. Some options, such as temperature and pressure, appear in each list: others,

such as bubble point are only available in one list. The options are:

First variable Second variable

Pressure / Temperature Temperature / Pressure

Enthalpy

Entropy

Molar Vapour Fraction

Mass Vapour Fraction

Specific Volume

Bubble Point

Dew Point

Enthalpy / Entropy Temperature

Pressure

Entropy / Enthalpy

Internal Energy Specific Volume

Specific Volume Temperature

Pressure

Internal Energy

The program does not let you select the same variable in both lists. The first variable

can be either a range or a list of values: the second is a single fixed value.

An additional Binary Calculation section and the centre section let you specify the

starting and finishing fractions for the first binary component in the stream.


1) In the list of calculation types, click Binary (VL Equilibrium).

2) Select the first variable and specify a range or list of values as required. See

“Specifying conditions for a pure component” on page 21.

3) Enter a single fixed value for the second variable.

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You don‟t need to do this for Bubble Point or Dew Point.

4) In the Binary Calculation section, click the appropriate option to specify whether

the composition is based upon a Mole Fraction or a Mass Fraction.

5) Also under Binary Calculation, specify which components in the mixture are to

be treated as the first and second components in a binary mixture. Any other

components in the original mixture are ignored.

6) Click any of the results tabs to start calculating results for the liquid and vapour

phases, and for the stream as a whole.


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Specifying a VLL Equilibrium calculation

This type of calculation calculates the vapour-liquid-liquid phase equilibrium first –

that is, the quantity and composition of three phases – and then calculates properties

for each phase and the stream as a whole.








1) In the list of calculation types, click VLL Equilibrium.




4) Click any of the results tabs to start calculating results for the vapour phase, the

two liquid phases, and the stream as a whole.

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Specifying an LL Equilibrium calculation

This type of calculation calculates the liquid-liquid phase equilibrium first, i.e. the










1) In the list of calculation types, click LL Equilibrium.




4) Click any of the results tabs to start calculating results for the two liquid phases

and for the stream as a whole.


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Specifying an SL Equilibrium calculation

Calculates the solid-liquid phase equilibrium first, i.e. the quantity and composition of

both phases, and then calculates properties for each phase and the stream as a whole.








1) In the list of calculation types, click SL Equilibrium.




4) Click any of the results tabs to start calculating results for the liquid and solid

phases, and for the stream as a whole.

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Specifying a VL Mass Flux calculation

Calculates the mass flux (as per API 520) for isentropic nozzle flow, i.e. for a

specified inlet temperature and pressure, calculates the properties for isentropic change

to a series of lower pressures.

The independent variables are the initial temperature and a series of pressures, the first

of which is considered the initial pressure. An isentropic flash calculation is carried

out from the inlet conditions to each of the specified pressures. By default, the

pressures are specified as a range. For each point, as well as the usual physical

properties, the maximum mass flux is calculated for isentropic flow (adiabatic and

reversible) through a nozzle from the inlet pressure to the specified downstream

pressure.

The method upon which this calculation is based is described in API Standard 520

Part 1, 8th edition (Dec 2008) (Annex C "Sizing for Two-phase Liquid/Vapor Relief",

Section C.2.1 "Sizing by Direct Integration of the Isentropic Nozzle Flow"). The

purpose is to identify the pressure at which the mass flux is a maximum: if greater

than the specified outlet pressure then this indicates choked flow in the nozzle.


1) In the list of calculation types, click VL Mass Flux.

2) Specify the inlet temperature as the first variable

3) Specify a range of values for the pressure as required. See “Specifying conditions


Typically the pressures will be in descending order, from the inlet pressure to the

outlet pressure.

4) Click any of the results tabs to start calculating results for the stream as a whole

and the vapour and liquid phases.

On the stream results, the conditions at which the Stream Mass Flux is a maximum

can be determined. Selecting the Stream Mass Flux column allows the results to be

plotted as a graph. The results in the columns for Stream Pressure and Stream Density

can be copied and pasted into an external pressure relief calculation, e.g. the “2 Phase

Direct Integration” calculation in PEL CAPRE.


55

Viewing results for a mixture For a mixture you can see a larger number of results tabs than for a simple calculation.

The number of tabs will depend on the nature of the mixture, the type of calculation

and the properties selected.

The following tabs may appear for mixtures:

Stream tab This shows the results for the stream as a whole: averaged over the

phases present. The tab is only available with one of the equilibrium calculations. The

properties shown are set by PhysPack and not determined by the Properties tab.

Liquid tab This shows the results for the liquid phase.

Liquid2 tab This shows the results for the second liquid phase. The tab is only

available with a VLL Equilibrium or LL Equilibrium calculation.

Vapour tab This shows the results for the vapour phase. The tab is not available for

LL Equilibrium or SL Equilibrium calculations.

Solid phase tab This shows the results for the solid phase. The tab is only available

with an SL Equilibrium calculation.

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Showing phase data for a mixture In addition to the various results tabs that show the calculated properties for the stream

and the different phases, you can view information about each of the phases that are

present in the stream. This feature is only available for mixtures.

In the stream results tab, the phase data has a tab for each of the phases present. In the

individual phase results tab, only the phase data for that tab appears. The information

about the phases in the stream includes a table (similar to the spreadsheet on the

stream builder) which shows:

Molar and mass amounts (by component) for the phase

Molar and mass fractions (by component) for the phase

For a liquid phase, if the vapour phase is also present, two extra column show the

K Value and Relative Volatility for each component.

Fraction of phase in stream – molar and mass

The bottom line of the window shows the total molar/mass fraction for the phase and

the molecular weight of the phase.

To view the phase data:

Do one of:

On the Results menu click Show Phase Data.

Right-click the table and click Show Phase Data.

The Phase Data table appears in the lower half of the main window.


57

Saving a phase as the feed stream

From the phase data table you can use the composition of the phase as the feed stream.

To save phase as feed stream

In the Phase Data table, right click and click Save Phase as Feed Stream.

The stream composition on the feeds tab of the Stream builder now matches the

chosen phase data.

Selecting the key component for relative volatility

The Relative Volatility values that can appear for a liquid phase are calculated relative

to the component in the mixture designated as the key component. By default this is

the first component added to the mixture, but you can change it.

The key component is shown on the context menu by a check mark.

To select a different key component:

In the Phase Data table, right click and click the component you want..

Copying phase data Just as you can copy results data to the clipboard, you can do the same for phase data.

Copying the phase data to the clipboard

To copy the phase data to the clipboard:

Right-click the table and click Copy Phase Data to Clipboard.

The whole table, including the column headers is copied to the clipboard as a tab


Copy selected phase data to the clipboard

Select the rows or selected cells and click Copy

To copy the phase data to the clipboard:

1) Select the required rows, columns or cells you want to copy.

2) Right-click the table and click Copy.

The selected values (without column headers) are copied to the clipboard as a tab


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Saving all constants data For a mixture you have a second command that is not available for single components.

This lets you save the constants data for all components in the mixture as a report file.

The file is in plain text format.

To save the constants data to a report:

1) Click the Constants tab

2) On the Results menu click Save report for all components.


click Save.

The data on the constants tab is saved as a plain text report file (.rep).

Calculation failures The advanced calculations for a mixture and the various setting you can use can

sometimes result in a calculation error. This can often be caused by selecting the

wrongs equilibrium method for your selected components.

Any error messages appear in the Messages tab.

59

Chapter 7 – Saving PhysPack data

When you have started to utilise the full power of PhysPack to model complex

calculations for a mixture, you will want to save some details from the calculation to

avoid having to repeat the process.

This chapter shows you how to save (and reopen) the complete calculation and how to

save the physical properties data so that it can be used in other PEL applications.

Managing calculations files A PhysPack calculation file (.physpack) stores all the information required to perform

a particular calculation: that is (1) the properties, specification and units settings and

(2) the physical properties information that defines the stream. The stream data can

either be embedded in the calculation file or saved as a separate file.

Saving a calculation file

To save a calculation file with embedded physical properties data:

1) On the File menu, click Save Calculation File > Embed physprops data.


To save a calculation file with a linked physical properties file:

1) On the File menu, click Save Calculation File > Link to physprops file.

You are first prompted to save the physical properties data.


You are then prompted to save the calculation data.


Opening a calculation file

To open a calculation file:

1) On the File menu, click Open Calculation File.

2) Navigate to select the file and click Open.

Managing physical properties files The physical properties information for a stream, that is the components that define

the mixture and their relative amounts or fractions, can be saved as a separate file.

This lets you run multiple calculations using a common physical properties file.

Two file formats are supported for physical properties files:

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60

.psm – a plain text file which allows PhysPack to look up components in the

databank to obtain their data.

.pds – a binary file which contains all of the data for individual components, so

calculations will always yield the same results even if data in the databank is

updated.

Saving a physical properties file

To save a physical properties file:

1) On the File menu, click Save PhysProps File.


Opening a physical properties file

To open a physical properties file:

1) On the File menu, click Open PhysProps File.

2) The default file type is the text format (.psm). To locate a binary format file, click

PDS format in the list of formats.

3) Navigate to select the file and click Open.

The application switches to the Component tab showing the Feeds tab of the Stream

builder.

61

Quick reference

The following tables define the commands on the menu system.

File menu

Command Action See

Open Calculation File Open an existing calculation file (.physpack)

“Opening a calculation file” on page 59

Save Calculation File > Embed physprops data

Save a calculation specification: phys props data is saved within the calculation file.

“Saving a calculation file” on page 59

Save Calculation File > Link to physprops file

Save a calculation specification: phys props data is saved in a separate phys props file which is named in the calculation file.

“Saving a calculation file” on page 59

Open PhysProps File Open a physical properties file (.psm, .pds)

“Opening a physical properties file” on page 60

Save PhysProps File Save the specification of the current stream in a physical properties file (.psm, .pds)

“Saving a physical properties file” on page 60

Exit Quit PhysPack “Quitting PhysPack” on page 5

Results menu

The following options only appear when the calculation results tabs are open

Command Action See

Display Current Graph

Show the current graph “Viewing the current graph” on page 28

Add Selected Results to Current Graph

Add extra column of results to current graph

“Adding selected results to the current graph” on page 29

Remove Selected Results from Current Graph

Remove column of results from current graph

“Removing Selected Results from Current Graph” on page 29

Graph Selected Results

View results as a graph “Viewing a graph of the results” on page 28

Show Phase Data Show/hide Phase data window “Showing phase data for a mixture” on page 56

Print Results as a Table > Print All Results

Print all the results on the current tab “Printing all the results” on page 30

Print Results as a Table > Print Selected Results

Print selected results on the current tab

“Printing selected results” on page 31

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62

Save Results as an Excel Worksheet

Save the results as an Excel worksheet

“Saving the results as an Excel worksheet” on page 32

Copy Results to Clipboard

Copy the results to the clipboard “Copying the results to the clipboard” on page 32

Copy Copy selected results to the clipboard

“Copying selected results to the clipboard” on page 32

The following options only appear when the constants tab is open

Command Action See

Save report for current component

Save the constants data for current component as a report file

“Saving constants data” on page 32

Save report for all components

Save the constants data for all the components as a report file (mixture only)

“Saving all constants data” on page 58

Help menu

Command Action See

Help – User Guide Open the online help version of the PhysPack User Guide

Help – PhysProps Open the online PPDS Reference Guide

Check for updates Not enabled in this version of the software

About Open the PhysPack splash screen

63

Revision history

The following table records the revision history of this guide.

Revision Date Description of change

1.0 07 Sep 2012 Guide written for PEL release 19.5

1.1 19 Oct 2012 VL Mass Flux calculation added

.

65

Glossary

60 Second Guide

A short self-paced tutorial that takes you through the main features of a PEL

application.

API

American Petroleum Institute – U.S trade association for the oil and gas industry.

Provides over 500 operating standards for the industry, many of them adopted by ISO

as international standards.

BIP

Binary Interaction Parameters.

Bubble point

The temperature at which a liquid consisting of two or more components starts to

evaporate – the onset of the vapour phase. See also Dew point.

For a pure component the bubble point and dew point are the same and are referred to

as the boiling point.

CAPRE

(pronounced CAPR-i) stands for CAlculations for Pressure Relief in Excel. A new

addition to the PEL software range, it provides engineers with a suite of commonly-

used pressure relief calculations within Excel.

CARN

Chemical Abstracts Registry Number. A scheme for uniquely identifying chemical

compounds. The code is in the form nnnnnn-nn-n.

Dew point

The temperature at which a vapour consisting of two or more components starts to

condense – the onset of the liquid phase.

Isenthalpic

A vapour-liquid phase equilibrium calculation defining either pressure or temperature

carried out at constant enthalpy.

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66

Isentropic calculation


carried out at constant entropy.

Isochoric calculation


carried out at constant volume.

LLE

Liquid-Liquid Equilibrium.

Phase envelope

A phase envelope marks the boundaries of the temperature and pressure combinations

where a mixture can exist as vapour and liquid fractions.

The envelope consists of a dew point curve intersecting a bubble point curve at the

mixture's critical point. The Dew point curve indicates the temperature and pressure

when a vapour having its pressure increased and/or temperature decreased will first

form drops of liquid. Similarly the Bubble point curve indicates where the first bubble

of vapour appears when heating and/or de-pressurising a liquid.

PPDS

Physical Properties Data Service. A software suite used extensively in the chemical

production, oil & gas, pharmaceutical, fine chemical, power generation and process

industries. It allows users to perform calculations and simulations across a wide range

of process and engineering applications. PPDS facilities are included in PhysPack.

The software is maintained by NEL (formerly the National Engineering Laboratory),

part of the German-owned TÜV SÜD group.

SLE

Solid-Liquid Equilibrium.

SMILES

Simplified Molecular Input Line Entry System. A mechanism for representing

molecular structures as a string of alphanumeric characters.

Stream

Any distinct and separate body of fluid, containing one or more components.

VLE

Vapour-Liquid Equilibrium. A condition for a two-phase fluid, where the rate of

evaporation (liquid to vapour) is the same as the rate of condensation (vapour to

liquid).

67

Index

A

Adding Components 36

Adding selected results to the current graph 29

B

Binary Interaction Parameters (BIPs) 38

Bubble point / dew point calculations 44

C

Copy selected phase data to the clipboard 57

Copying selected results to the clipboard 32

Copying the phase data to the clipboard 57

Copying the results to the clipboard 32

Creating your own set of units 25

D

Describing the model 39

E

Enthalpy / Entropy / Specific Volume calculations 43

F

File menu 61

H

Help menu 62

I

Isenthalpic / Isentropic / Isochoric calculations 45

M

Multiple value graphs 28

O

Online documentation 7

Online help 6

Opening a calculation file 59

Opening a physical properties file 60

P

PEL Support Services 7

Printing all the results 30

Printing selected results 31

R

Removing selected results from the current graph 29

Results menu 61

S

Saving a calculation file 59

Saving a phase as the feed stream 57

Saving a physical properties file 60

Saving constants data 32

Saving the current stream 39

Saving the results as an Excel worksheet 32

Selecting a pure component 15

Selecting an aqueous solution 18

Selecting molar or mass units 25

Selecting the key component for relative volatility 57

Specifying a Binary (non-equilibrium) calculation 48

Specifying a Binary (VL Equilibrium) calculation 49

Specifying a Nonequilibrium calculation 46

Specifying a VL Equilibrium calculation 42

Specifying a VL Mass Flux calculation 54

Specifying a VL Phase Envelope calculation 47

Specifying a VLL Equilibrium calculation 51

Specifying an LL Equilibrium calculation 52

Specifying an SL Equilibrium calculation 53

Specifying conditions for a pure component 21

Specifying conditions for an aqueous solution 23

Specifying the LLE method 39

Specifying the SLE method 39

Specifying the type of calculation 41

Specifying the VLE method 37

T

The first 30 seconds … 9

The next 30 seconds … 10

U

Using the condition variables in pairs 21

Using VLE modelling 22

PhysPack User Guide

68

V

Viewing a graph of the results 28

Viewing constant properties 16, 19

Viewing quality assurance indicators 17

Viewing the calculated results 17, 19

Viewing the current graph 28

ABB Limited

PEL Support Services Daresbury Park, Daresbury, Warrington, Cheshire, WA4 4BT United Kingdom Tel: +44 (0) 1925 741126 Fax: +44 (0) 1925 741265 Email: [email protected] www.pelsoftware.com

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