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ChemSheet User’s Guide

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ChemSheet User’s Guide

TABLE OF CONTENTS

WHAT IS CHEMSHEET.............................................................................................................1

DEFINITION OF TERMS............................................................................................................1

NOMENCLATURE USED IN CHEMSHEET..............................................................................1

SYSTEM REQUIREMENTS.......................................................................................................2

INSTALLATION..........................................................................................................................2

UNINSTALLATION....................................................................................................................2

GETTING HELP..........................................................................................................................2

USING CHEMSHEET.................................................................................................................3

USING GLOBAL CONDITIONS.................................................................................................4

EQUILIBRIUM COMPOSITION OF MIXTURE PHASES..........................................................4

ADDING CHARTS......................................................................................................................9

USING STREAMS....................................................................................................................10

COMBUSTION EXAMPLE.......................................................................................................10

ADDING MORE CALCULATION STEPS................................................................................17

CHANGING STATUS...............................................................................................................19

USING TARGETS....................................................................................................................20

USING ONE-DIMENSIONAL PHASE-MAPPING....................................................................22

PROGRAMMING WITH CHEMSHEET....................................................................................24

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ChemSheet User’s Guide

What is ChemSheet
ChemSheet combines the flexibility and practicality of spreadsheet applications with the thermodynamic and simulation
capabilities of Gibbs Energy minimisation. Its applications are appropriate for metallurgical, chemical and process
industries as well as for geochemists and environmentalists. Also there is a special appeal to those in universities and
chemical education.
ChemSheet allows rigorous chemical and thermodynamic calculations to be computed within the familiar environment of
Microsoft Excel spreadsheet. Even though ChemSheet uses complex numerical procedures with extensive thermodynamic
data linked with appropriate reaction kinetics, it produces the results on a simple Excel spreadsheet and thus makes the
simulation accessible to the general user.
ChemSheet applies the ChemApp thermodynamic programming library, which handles repetitive complex equilibrium
calculations for a diverse range of chemical and thermodynamic applications. ChemApp can be used to calculate both the
composition and the thermodynamic properties of a multi-phase, multi-component system at given conditions. With
ChemApp, versatile one-dimensional phase-mapping and target calculations can also be done.
The applications range from analysis of laboratory and environmental data to practical process simulation and design. In
ChemSheet each process chemistry model can be formatted to practical worksheet from which calculations are made.

Definition of Terms
A thermodynamic system consists of a number of phases, where some may have a composition expressed as amounts of a
number of phase constituents, and others can have an invariant composition. Phases are divided into three groups
1. The gaseous phase.
2. Condensed mixtures.
3. Condensed stoichiometric phases (invariant phases).
Phases and phase constituents always have thermochemical properties (activities, chemical potentials, enthalpies, volumes,
etc.). Phase constituents have compositions expressed as amounts (i.e. stoichiometric coefficients) of a number of
components. A component is a system-wide entity, which is stressed by calling it a system component. Usually components
are elements, but it is also possible for them to be stoichiometric combinations of elements. For example, in an oxide system
based on calcia and silica, CaO and SiO2 may be used, as well as Ca, Si, and O.
Note In the more general case, it is necessary to ensure that the stoichiometric formulae are linearly
independent.
Note In a thermodynamic data-file, the total number of components of a given system includes phase-
internal electrons; for example, when an aqueous phase is present. However, they are not counted when
the maximum number of possible phases in the system is determined according to Gibbs' phase rule.
At chemical equilibrium, the absolute activities (chemical potentials) of the components are the same in the entire system.
Internally in ChemApp thermodynamic programming library, the actual number of system components is calculated as the
rank of the stoichiometry matrix. This number may vary during the course of the Gibbs Energy minimization when only
constituents with amounts greater than zero are considered. Should a complete reaction have taken place between two or
more of the entered system components at equilibrium, it might not always be possible to calculate their absolute activities.
For example, if in the system Mg-Si 2 mol of Mg and 1 mol Si are entered, the stoichiometric condensed phase Mg2Si
forms at low temperatures, and the activity of Mg2Si will be calculated, but not the activities of Mg and Si.
In order to calculate the thermochemical properties for the components, their respective reference state has to be selected.
As this cannot be done in a general way, calculation of these properties is not included in ChemApp and ChemSheet.

Nomenclature Used in ChemSheet

Names of components, constituents of a phase, phases and streams are case sensitive and can consist of a string of letters up
to 24 characters in length. For example, 'CO' and 'Co' are two different phase constituents. Some names are reserved
because they have some special meaning in ChemSheet:

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ChemSheet User’s Guide

 The name EQUILIBRIUM cannot be used as a stream name. If you have selected Add Previous Equilibrium as a
Stream in the Options dialog box you can use the name EQUILIBRIUM to refer to the previous equilibrium. This
feature can be used in Constituent and Result dialog boxes.
 The name ALL cannot be used as a phase, a constituent, or component name. You can use the name ALL to refer all
phases in the system, all constituents in a phase and so on. This feature can be used in Constituent, Condition and
Result dialog boxes.

System Requirements
 Intel 486DX processor or better
 Microsoft Windows 95/98 or NT 4.0 operating system or later
 Microsoft Excel 97/8.0 or later

Installation
To install ChemSheet run the Setup.exe program in installation CD or diskette 1 and follow the instructions. To complete
your ChemSheet installation you should add ChemSheet Add-In module to Excel.

 To add ChemSheet Add-In

1 Click Add-Ins in the Tools menu.
2 Click Browse.
3 Select C:\ChemSheet\ChemSheet.xla.
4 Click Ok.
5 Enter registering information. Enter any text for name and company.
6 Click Ok.

Uninstallation
You can uninstall ChemSheet software using Windows Add/Remove programs dialog box that can be found in the
Control Panel. From there you can also reinstall ChemSheet to restore missing files and settings. For that you will need
the original installation diskette(s) (if you installed from a diskette).
Before uninstalling you should remove ChemSheet Add-In module from Excel.

 To remove ChemSheet Add-In

1 Click Add-Ins in Tools menu.
2 Uncheck ChemSheet Add-In in Add-Ins available list box.

Getting Help
Besides this document you can browse the ChemSheet Help file.

 To view ChemSheet Help file

1 Click the New ChemSheet Model button in ChemSheet toolbar or click New in Tools/ChemSheet menu to open
ChemSheet dialog box.
2 Click Help.
3 Click Contents on Help toolbar to go to the Contents page.

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Using ChemSheet
Here is a picture of a ChemSheet model using Streams with some added comments. It contains many Excel features that
can be used with ChemSheet.

Temperature condition. It uses StepIndex variable to Chart for the total precipitation as a function of
vary temperature from 200 to 1000 Celsius degrees. temperature. The chart is linked to range G18:H22
and is automatically updated when the model is
calculated.

Input streams temperatures, pressures and Temperature result. Values are stored ChemSheet toolbar
compositions. These values are entered to range G16:G22. The first two cells
directly to the worksheet cells. They may are reserved for the headers, which are
also contain formulas as in the temperature automatically added.
condition

In this model all the necessary input values are entered to worksheet cells, so they can be quickly changed without opening
the ChemSheet dialog box. The cells are linked to the ChemSheet model using cell references and the values of cells are
evaluated for each calculation step. After changing one or more values in the linked cells the model needs only to be
calculated again by clicking the Calculate ChemSheet Model in ChemSheet toolbar and the result values and charts linked
with them are automatically updated.

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Using Global Conditions

Using this method, you merely need to set single values for pressure and temperature, and enter incoming species to define
the initial composition of the system. For example, if you wish to calculate the thermodynamic equilibrium for the system
SiO2-CaO, using a thermodynamic data-file that among others contains the elements Ca, Si, and O, you would only need to
define the temperature and pressure of the system, and the total amounts of SiO2 and CaO present. You can also enter
incoming amounts as components, i.e. total number of elements Ca, Si, O present. As a result of the calculation you will be
given the amounts of the stable phases in the system, and if a phase is a mixture phase, also the equilibrium composition of
the phase.

Equilibrium Composition of Mixture Phases

This example will demonstrate what information can be obtained from ChemSheet regarding the equilibrium composition
of mixture phases.
The aim is to show how ChemSheet is used to retrieve information about the equilibrium state of a mixture phase. The gas
phase of the system C-O-Si (ChemSheet\Data\COSi.dat) being used as an example.
The information to be retrieved includes:

The equilibrium amount of the phase

The mole fraction of the phase

The equilibrium amounts of the phase constituents.

The mole fractions of the phase constituents.

 To start a new ChemSheet model

1 Open Excel if it is not already open.
2 If necessary open a new workbook by clicking New in File menu.
3 Enter the values to the cells in worksheet Sheet1 as shown in the next picture.

As you can see the actual condition values in column B are left blank. We will enter them later after we have defined the
ChemSheet model but we could have entered them now as well.

 To define the model

1 Click the New ChemSheet Model in ChemSheet toolbar or click New in Tools/ChemSheet menu to open
ChemSheet dialog box.
2 Click Browse.
3 Locate \ChemSheet\Data folder in the Find In box, and then select COSi.dat file from the list of data-files by double
clicking it.
4 In Number of Calculation Steps box, type 5.

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Next we define the initial conditions.

 To define the Conditions

1 Click Add to open Conditions dialog box.
2 Select Temperature from the Option list
3 Click the Value box to activate it, and then click cell B2 to copy its address to the box.
4 Click Add to add the Condition and to keep the dialog box open.
5 Select Pressure from option list.
6 Click the Value box to activate it, and then click cell B3 to copy its address to the box.
7 Click Add.

8 Select Incoming Amount from the Option list.

9 Select GAS from the Phase list.

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10 Select CO from the Constituent list.

11 Click the Value box to activate it, and then click cell B4 to copy its address to the box.
12 Click Add.
13 Select SiO2(quartz) from the Phase list
14 Click the Value box to activate it, and then click cell B5 to copy its address to the box.
15 Click Ok to add the Condition and to close the dialog box. Or you can first click Add, and then click Cancel.

Now the Conditions page should look like this.

Tip You can adjust the widths of the columns in the list by dragging the vertical bars between the
column headers (or double click the bar which will automatically adjust the width).
Next we define the results.

 To define the Results

1 Click the Results tab.
2 Click Add to open the Results dialog box.
3 Select Temperature from the Option list.
4 Click the Output Range box to activate it, and then select range E2:E8 to copy its address to the box.
Important As we do five successive calculations and use automatically generated headers we need
seven cells to store all the result values.
Tip You can always select more cells than is needed. This is useful if you need to change the
number of calculation steps.

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5 Select the Comments check box.

6 Click Add.
Note You can see that the headers are inserted at this point to the first two cells in the Output
Range. The comments will be added when you calculate the model.
7 Select Amount from the Option list.
8 Click the Output Range box to activate it, and then select range F2:F8 to copy its address to the box.
9 Click Add.
10 Select GAS from the Phase list.
11 Click the Output Range box to activate it, and then select range G2:G8 to copy its address to the box.
12 Click Ok.

Now the Results page should look like this.

Next you may save the model.

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 To save the model

1 Click Save.
2 If you have not saved the workbook yet then Save As dialog box opens and you can name the workbook.

Note Pressing the Save button in ChemSheet dialog is the same as first closing the ChemSheet
dialog box and then clicking Save command in File menu. That is because the ChemSheet model is
saved within the Excel workbook. If you close a saved Excel workbook that contains a ChemSheet
model then the model is readily usable when you open the workbook next time.
Now we have defined all the initial conditions and results in Chemheet dialog box that we need in order to calculate the
model for the first time. As you remember we have not entered the actual condition values to column B yet. So next we
should close the ChemSheet dialog box and enter the missing values.

 To close the ChemSheet dialog box

1 Click Close.

Enter the condition values to column B as shown in the next picture.

As you can see cell B2 contains a formula “=700+(StepIndex-1)*200”. The values in other cells are just constants. This
way we can vary the value of the temperature as the calculation proceeds. For every calculation step the given temperature
formula changes as StepIndex variable changes. StepIndex is a variable that is defined in Excel. When the calculation
starts its value is one. It is increased by one for every successive calculation step until it reaches the number of calculation
steps which was set to five in our example. After the calculation the value of the StepIndex variable is reset to one again.
Now you are ready to calculate your first ChemSheet model.

 To calculate the ChemSheet model

1 Click Calculate ChemSheet Model in ChemSheet toolbar or click Calculate in Tools/ChemSheet menu.

As you can see, the value of temperature in cell B2 changes from 700 to 1500, as the value of the StepIndex variable
changes from one to five. When the calculation is over, the value of the StepIndex variable is reset to one again.
Next we calculate mole fraction of the gas phase in the system. This can be done quite easily with a simple Excel formula.

 To calculate the mole fraction of the gas phase

1 Select cell G10, and type formula “=G2”.
2 Select cell G11, and then type formula “=G4/F4”.
3 Copy the formula to range G11:G15 by dragging the fill handle in the cell border over the range.

Next we edit the model and add the equilibrium amounts of all constituents in the gas phase as a result.

 To edit the ChemSheet model

1 Click the Edit ChemSheet Model in ChemSheet toolbar or click Edit in Tools/ChemSheet.

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2 Click Results tab.

3 Click Add.
4 Select Amount from the Options list.
5 Select GAS from the Phase list
6 Select ALL from the Constituent list.
7 Click the Output Range box to activate it, and then select range H2:V8 to copy its address to the box.
Important The selected range must contain enough columns for all the constituents in the phase.
The number of constituents (required number of columns) is shown in the information box at the
lower part of the Result dialog box.
8 Click Ok.

Now calculate the model again.

Lastly we calculate the mole fractions of all the constituents in the gas phase. This can be done in a similar way than we did
with the mole fraction of gas phase.

 To calculate the mole fractions of all the constituents in gas phase

1 Select cell H10, and type formula “=H2”.
2 Copy the formula to range H10:V10.
3 Select cell H11, and then type formula “=H4/G$4”.
Important Remember to add the dollar sign to the formula.
4 Copy the formula to range H11:V15.

Adding Charts
You may finish your models by adding charts to the workbook. You may for example add the mole fractions as a chart.
It is easier to create the chart, if all the data columns start at the same row. As we want the temperature to be the X axis, we
should first copy the temperature values to start at the same row than the mole fraction values.

 To copy the temperature values

1 Select range F10, and then type formula =E2.
2 Select range F11, and then type formula =E4.
3 Copy the formula to range F11:V15.

 To add the mole fractions as a chart

1 Select range F10:V15.
2 Click Chart in Insert menu
3 Select XY (Scatter) from Chart type list.
4 Select Scatter with data points connected with lines from Chart sub-type list.
5 Click Next.
6 Select Columns in Series in option
7 Click Next.
8 Enter remaining settings.

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Using Streams
ChemSheet can be used as a very powerful tool at the heart of a process simulation program to determine the chemical
equilibria and heat balances involved. The concept of streams in ChemSheet is especially helpful in this respect. A stream
is a mixture of non-reacted matter of constant temperature and pressure which is transferred to a reaction zone. Several such
streams can be defined to constitute the material input for an equilibrium calculation.
The Streams method must be used for calculation of the changes of extensive properties of reactions; for example, those
involving the heat balance of a combustion process. It is also convenient to use it for reactor calculations, where you know
what is entering the system and you wish to calculate results at various stages during and at the end of the process.
It is easy to see how, using the concept of streams, ChemSheet can be used to model highly complex multicomponent,
multiphase equilibria very quickly and reliably.
NOTE When setting the incoming amounts for a stream, only phases and phase constituents can be
used for this purpose. If one wants to enter the incoming amounts for a stream in terms of the system
components (i.e. usually the elements), but the phase constituents of that phase are not elements, one
has to perform an intermediate calculation using another ChemSheet model that uses global conditions.

Combustion Example
In this example, a combustion process is simulated using the system C-N-O. While the system itself is very simple, it
provides a good basis for demonstration. Particular attention will be paid to the conditions leading to the formation of
condensed phases (i.e. precipitates formed during the combustion). With the simple data-file used, this possible precipitate
is solid carbon.
In real-life applications similar to the one below, ChemSheet may be used with data-files describing systems of up to 30
system components containing many hundreds of species, investigating the cooling of exhaust gases from incineration
processes.
Using multiple connected reaction “chambers”, each at a different temperature, the formation of condensed phases in each
stage can be analysed. The result is a simulation program, which permits the understanding and optimisation of the process
described.
In this example we assume that a mixture of CO 2 and CO at 200 C and 1 bar, which can be thought of as an exhaust gas
from a previous incomplete combustion process, is entering the reactor. To further combust this gas, air at room temperature
is supplied. The air in this example is supposed to consist of O 2 and N2 at a ratio of 1:4. The amount of air supplied will be
kept constant at first, but varied later on to investigate its influence on the formation of condensed phases. The temperature
of the reaction chamber is varied to look at its influence on the process. As you can see cell C8 contains formula
“=StepIndex*200”. The actual value of the formula is not defined yet as the StepIndex variable is not defined yet. You
don’t need to worry about that. StepIndex variable will be defined later after you have defined the ChemSheet model itself
in ChemSheet dialog box.
As the temperature of reactor is varied, the material formed at equilibrium would then be separated into a gas phase and the
condensed phases, which leave the reactor in different streams. If the model would be extended to reflect a more complex
process, consisting of several different stages, these two outputs could in turn make up input streams for subsequent reactor
stages.

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NOTE The above picture is taken from \ChemSheet\Samples\Stream_Combustion1a.xls file. It can be

used as a starting template to build this model by following the steps that are given next.

 To define the ChemSheet model

5 Click the New ChemSheet Model in ChemSheet toolbar or click New in Tools/ChemSheet menu to open
ChemSheet dialog box.
6 Click Browse.
7 Locate \ChemSheet\Data folder in the Find In box, and then select CNO.dat file from the list of data-files by double
clicking it.
8 Click Options.
9 Click the Streams option in the Initial Conditions, and then click Ok.
10 Click Yes in the Warning dialog box. It means that all the previously defined Conditions and Results will be
removed. As we have not defined any yet, we don’t need to worry about the warning.
11 In Number of Calculation Steps box, type 5.

As you can see the Streams and Constituents pages that were previously grayed are now enabled and the Streams page is
selected by default.

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 To define the Streams

1 Click Add to open the Stream dialog box.
2 Type CO2/CO in the Name box.
3 Click the Temperature box to activate it, and then click cell A11 to copy its address to the box.
4 Select C from the Unit list.
5 Click the Pressure box to activate it, and then click cell A12 to copy its address to the box.

6 Click Add to add the CO2/CO Stream and to keep the dialog box open in order to define the Air Stream.
7 Type Air in the Name box.
8 Click the Temperature box to activate it, and then click cell E11 to copy its address to the box.
9 Select C from the Unit list.
10 Click the Pressure box to activate it, and then click cell E12 to copy its address to the box.

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11 Click Ok to add the Air Stream and to close the dialog box.

Now the Streams page should look like this.

 To define the Constituents

1 Click the Constituents tab.
2 Click Add to open the Constituents dialog box.
3 Select CO2/CO from the Stream list.
4 Select GAS from the Phase list.
5 Select CO2 from the Constituent list.
6 Click the Amount box to activate it, and then click cell A17 to copy its address to the box.
7 Select mol/s from the Unit list.

8 Click Add.

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9 Add the other constituents by repeating the previous steps.

Important Remember to select Air from Stream list for O2 and N2 constituents.

Now the Constituents page should look like this.

 To define the Conditions

1 Click the Conditions tab.
2 Click Add to open the Conditions dialog box.
3 Select Temperature from the Option list.
4 Click the Value box to activate it, and then click cell C8 to copy its address to the box.
5 Select C from the Unit list.
6 Click Add.
7 Select Pressure from option list.
8 Click the Value box to activate it, and then click cell C9 to copy its address to the box.
9 Click Ok.

Now the Conditions page should look like this.

 To define the Results

1 Click the Results tab.
2 Click Add to open the Results dialog box.
3 Select Temperature from the Option list.

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4 Click the Output Range box to activate it, and then select range G16:G22 to copy its address to the box.
5 Select C from the Unit list.
6 Select the Comments check box.

7 Click Add.
8 Select Amount from the Option list.
9 Select C_DIAMOND_A4 from the Phase list.
10 Click the Output Range box to activate it, and then select range I16:I22 to copy its address to the box.
11 Select gram/s from the Unit list.
12 Click Add.
13 Select C from the Phase list.
14 Click the Output Range box to activate it, and then select range J16:J22 to copy its address to the box.
15 Click Ok.

Now the Results page should look like this (the Headers and Comments fields are not visible here but they should contain
value True).

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Now we have defined all we need in the Chemheet dialog box.

 To close the ChemSheet dialog box

1 Click Close.

As you can see, the value in cell C8 is now defined as the StepIndex variable is defined. The temperature is evaluated as
200 as the value of the StepIndex variable is one.

 To calculate the model

1 Click Calculate ChemSheet Model in ChemSheet toolbar or click Calculate in Tools/ChemSheet menu.

As you can see, the value of temperature changes from 200 to 1000 as the value of the StepIndex variable changes from
one to five. When the calculation over, the value of the StepIndex variable is reset to one again.
Next we calculate the amount of total precipitation, which is the sum of C_DIAMOND_A4 and C phases. This can be done
quite easily with an Excel formula.

 To calculate the total precipitation

1 Select cell H16, and then type Total precipitation.
2 Select cell H17, and then type formula =I17.
3 Select cell H18, and then type formula =SUM(I18:J19).
4 Copy the formula to range H19:I22 by dragging the fill handle in the cell border over the range.

Next we add the total precipitation as a chart to our model.

 To add the total precipitation as a chart

1 Select range G18:H22.
2 Click Chart in Insert menu, and then follow the steps in Chart Wizard.

Finally we may format the result table.

 To format the result table

1 Select G16:J22.
2 Click Autoformat in Format menu.

This is how the final model looks like.

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Adding More Calculation Steps

The chart doesn’t look so good as the model was calculated using only five steps. Next we are going to add more calculation
steps to the model and to decrease the temperature interval in temperature formula in order to obtain better looking results.
First we need to resize all the ranges that contain the results. That can be done editing the entries in Results page one by
one. But if we have defined a lot of results that can be very time consuming. Luckily there is other way to do it. Namely to
insert new rows to the worksheet. If the rows are inserted inside the ranges that contain the results then they are resized
automatically.

 To add more calculation steps

1 Select range G19:J38.
2 Click Cells in Insert menu.
3 Select Shift cells down option.
4 Click Ok.
5 Copy the formula in cell H18 to cells in column H that are empty.
6 Enter formula =200+(StepIndex-1)*20 to cell C8.
7 Click Edit ChemSheet Model in ChemSheet toolbar or click Edit in Tools/ChemSheet menu.
8 Clear the old value in Number of Calculation Steps box and type 25.
9 Click Close.
10 Click Calculate ChemSheet Model in ChemSheet toolbar.

Here is the new chart. It looks definitely a lot better than the old one.

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Total precipitation
10.00
9.00

Amount/gram/s
8.00
7.00
6.00
5.00
4.00
3.00
2.00
1.00
0.00
0 200 400 600 800
Temperature/C

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Changing Status
You can ignore one or more phases and phase constituents in the equilibrium calculation by changing their status. If you
ignore some constituent, it can still serve as an incoming species. The default status is that stored in the thermodynamic
data-file. The status for a phase can be changed implicitly, dependent on the explicit changes of the statuses of its
constituents. For example, if all constituents of a phase are made dormant, the phase will also be dormant. The following
table shows different options for status.

Status Description
ENTERED The phase or constituent is included in the equilibrium calculation. An included phase is not
necessarily stable at equilibrium.
DORMANT The phase or constituent is excluded from the mass balances (it will appear with zero amount at
equilibrium), but its activity is calculated. If the calculated activity for a phase is greater than one, it
would be stable if entered.
ELIMINATED The phase or constituent is ignored in the equilibrium calculation.
The status for a phase can be changed implicitly, dependent on the explicit changes of the status of its constituents. For
example, if all constituents of a phase are made dormant, the phase will also be dormant. Whereas complete phases can
always be set ENTERED, DORMANT or ELIMINATED, some restrictions apply for phase constituents.
 For phases described by the models SUBS and QUAS, the status for single phase constituents cannot be changed.
 For sublattice type phases or for phases which internally are considered to contain sublattices (models SUBL, SUBO,
SUBI, SUBM, QUSL, GAYE, QSOL), the entered phase constituents must constitute a proper sublattice phase. As an
example, if the sublattice setting is (A,B)(C,D), the phase constituents AC and AD, and thus implicitly A, can be
removed, but not AC and BD.
A common reason for changing the status of a phase is for instance the desire to calculate a metastable equilibrium or to
increase the computational speed in systems containing miscibility gaps.
Let us still continue with the Combustion model. You may have wondered why the C_DIAMOND_A4 phase is included in
the model, as we are unlike to get any diamond. Now we may experiment a little. Next we are going to change the status of
C phase to DORMANT.

 To change the status of a phase

1 Click the Edit ChemSheet Model in the ChemSheet toolbar or click Calculate in Tools/ChemSheet menu.
2 Click Status tab.
3 Click Add.
4 Select C from the Phase list
5 Enter DORMANT to the Status box.
6 Click Ok.
Now calculate the model again. This time some C_DIAMOND_A4 is formed!
NOTE This example contains also a warning. The results that you get depend on the thermodynamic
data-file used. If some important constituent is not present in the system, the results may be misleading.

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Using Targets
Target calculations are those in which certain target conditions are set, for instance the value of a heat balance or the
presence of a phase at equilibrium. These conditions can only be satisfied when the value of some other variable, i.e. the
target variable, is adjusted accordingly.
ChemSheet is able to perform two types of target calculations:
 Extensive property target calculations
 Phase target calculations
An extension of the second type is the one-dimensional phase-mapping calculation.
When performing an extensive property target calculation with ChemSheet, one of the following five extensive properties
of the system can be selected as a condition:
 Enthalpy
 Entropy
 Gibbs energy
 Heat capacity
 Volume
Note – Changes in the extensive properties are calculated if the Streams method was used to define the
initial conditions. Otherwise the extensive properties for the system or a phase are calculated using the
reference state inherent in the data file used for the calculations.
A phase target calculation enables conditions to be determined for a selected phase to be present at equilibrium (formation
phase target), or the precipitation of another, unspecified phase, from a specified mixture phase (precipitation phase target).
Below is an example of the conditions of the precipitation target calculation:

Temperature is the target variable. Its value is searched between the lower and upper limits using the initial value as the
starting point of the iteration.

The value of the final temperature is found when the activity of GAS phase is one and its amount is greater than zero and
the activity of some unspecified phase in also one but its amount is zero.
For the complete example see the Target_Precipitation.xls file in ChemSheet\Samples directory.
If you have defined other conditions than temperature, pressure, or incoming amount, then you have to add a target variable.

 To add a new target variable

1 Select the New command in the ChemSheet menu or press the New ChemSheet Model button in the ChemSheet
toolbar. If you don’t have the ChemSheet toolbar visible, select it with the Toolbars command in View menu. The
ChemSheet Dialog appears.

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2 Select Targets tab in Calculation data.

3 Select Add to add a new target variable. The Target dialog box appears.
4 Select the target variable and the necessary options for it and give its value. If some controls are greyed, then their
values are not needed for the selected set of options.
5 Click Ok.

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Using One-dimensional phase-mapping

One-dimensional phase mapping is used to search for all phase transitions within a given interval of a search variable. The
search variable can be total pressure, temperature, or incoming amount(s) (initial composition).
Using one-dimensional phase mapping thus makes it very easy to find phase boundaries in a variety of phase diagrams, such
as those with temperature/composition, pressure/composition, and temperature/pressure as axes. Otherwise one-dimensional
phase mapping is same as phase target calculation. You add a new search variable for phase mapping just as you would add
a new target variable – you only have a different set of options to choose from.
For example if you want to do one-dimensional phase mapping where pressure is the search variable (see the line 1 in the
figure below).

The Fe2SiO4-Mg2SiO4 pressure/composition phase diagram at 1000 (calculated using ChemSage)

 To calculate One-dimensional phase-mapping

1 Set Calculation in Options dialog as One-dimensional phase mapping.
2 Add necessary Conditions (temperature and initial composition).

3 Add the Target (search) variable (pressure).

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If the value of StepIndex is 1 then the lower limit evaluates as 120000 and the upper limit as 123000. The added Results are
retrieved at the lower limit 120000 and at possible phase boundaries between 120000 and 123000. If the number of steps is
greater than 1 then the next lower limit is 123000 and upper limit is 126000 and again Results are retrieved at the lower
limit and at possible phase boundaries. If the total number of steps is 11 then the last set of lower and upper limits are
150000 and 153000. This example could be done just with one step -the lower limit set as 120000 and the upper limit as
150000. But then you could miss some information (if the results vary between the phase boundaries).
For the complete example see PhaseMap_Pressure.xls file in ChemSheet\Samples directory. In the example file the values
and formulas are defined as references so that they can be entered directly to worksheet cells.
Sometimes a phase boundary may be reported twice. For example if the search variable is the temperature then there may be
two phase boundaries at the same temperature (but the amounts of some phases differ). The temperatures may not have
exactly the same value but considering the numerical accuracy of the calculation they represent the same temperature.

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Programming with ChemSheet

You can run all the functions that are present in the ChemSheet toolbar with Visual Basic. In order to do that you should
add a reference to ChemSheet Add-In in your project.

 To add reference to ChemSheet

1 Click the Edit ChemSheet Model in the ChemSheet toolbar or click Calculate in Tools/ChemSheet menu.
2 Select References command in Tools menu
3 Check ChemSheet in Available References list.

Next you can add a Cmmond control to the worksheet that calculates the model.

 To add a command button

1 Click the Command in the Control toolbox.

2 Place the control on the worksheet.

3 If you need to format the control properties like its font right click it and select Properties.

4 Double click the control. Excel automatically activates Visual Basic Editor and places code for controls callback
macro. Add ChemSheet.Calc call to the macro

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Private Sub CommandButton1_Click()

ChemSheet.Calc
End Sub
The following table shows the ChemSheet macros that user can call:

Macro Description
cshNew Same as the New ChemSheet Model command in ChemSheet toolbar.
Creates a new model.
cshImport(optional rngArea as Range) Same as the Import ChemSheet Model command in ChemSheet toolbar.
Imports a model to a worksheet. The optional parameter rngArea is the cell
in the upper left corner of the imported data. If it missing then the Import
dialog box is opened so the user can enter the address of that cell.
cshExport(optional rngArea as Range) Same as the Export ChemSheet Model command in ChemSheet toolbar.
Exports a model from a worksheet. The optional parameter rngArea is the
cell in the upper left corner of the exported data. If it missing then the
Export dialog box is opened so the user can enter the address of that cell.
cshEdit Same as the Edit ChemSheet Model command in ChemSheet toolbar.
Opens the ChemSheet dialog box.
cshCalc Same as the Calculate ChemSheet Model command in ChemSheet
toolbar. Calculates the active ChemSheet model.

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