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Frequently Asked Questions
What Prode thermoPhysical Properties generator does ?
This tool provides a thermodynamic framework for calculating thermophysical properties (equilibrium, transport etc.) of pure components and multicomponent's streams. Entirely written in C++ language (and part of a set of classes for thermodynamic calc's) it is available in form of DLL for direct access from electronic sheets, user-defined programs etc.
What a library is ?
A dynamic-link library (DLL) is a binary file that acts as a shared library of functions that can be used simultaneously by multiple applications. A DLL integrates with spreadsheets (Microsoft EXCEL, LOTUS 1-2-3 etc.) , user defined programs (Visual-Basic, C, C++ etc.) providing additional methods (functions) , extending features etc. Being a compiled code it runs very fast so providing an effective mean to extend application's features.
How do I include this tool in software I am distributing ?
There is a developer licence for this, ask Prode for details.
What data and structures does this framework include ?
Prode Physical Properties generator (base version) includes a compilation with physical properties data on 970+ components and a set of procedures for calculating properties of pure and multicomponent streams.
How many components does a stream include ?
A stream entity may include from 1 (pure) up to 500 comp's , the user can define the max number, a stream with a large number of components requires a somewhat large time to solve.
How do I define the thermodynamic models ?
Each stream has its own thermodynamic model for equilibrium, enthalpy, entropy calc's, this allows a great flexibility being the model directly associated to the stream composition.
How do I define 20 or more streams (to simulate a complex plant) ?
Prode allows to define 100 or more different streams. A large number of streams is frequently required for simulating complex plants, Prode thermoPhysical Property generator has built-in functions to manage all requirements (computer memory allocation , stream's definition and access etc.)
How do I reference a stream ?
Stream are referenced by a numeric code (a integer) in calling functions, a typical call is : setop(stream, double t, double p), where the value of stream (integer 1-100) references the stream.
How do I define a stream (and access data) ?
Prode distribution includes a few graphical objects, under windows there is a editor from where to access all stream's data (gas & liquid flow, component's percentages, thermodynamic models etc.). This is useful for defining stream's compositions and have a immediate view of stream's data. In addition several methods permit to read and set all stream's properties.
How do I enter Binary Interaction Parameters (BIP's) ?
In stream's definition form a table permits to enter Binary Interaction Parametres. All non-ideal thermodynamic methods (EOS and Activity Coefficents) may require the definition of these parameters to work as intended. BIP's are available in literature (DECHEMA etc. sources), another way is to regress equilibrium data supplied by the user.
How do I define stream's operating conditions ?
There is a specific method for defining a new operating condition : setop(stream, double t, double p), which requires a stream, operating pressure and temperature, this method performs an isothermal flash and sets operating conditions.
How do I perform isothermal, isoenthalpic, isentropic, liquid-fraction flash operations ?
Several different flash operations are supported : T-P, T-V, T-H, T-PF, H-P, S-P, V-P....
Agreement made between Prode "Prode" and "User".
Excel application example : calculate properties of pure fluids and mixtures
With Prode Properties it is easy to calculate the properties of a pure fluid or a mixture,this Excel application example shows how to calculate a value in a cell and print table of values for different properties in a specified range of temperature and pressure
First step: define the stream (components, compositions etc.)
Properties includes a Stream editor which permits to access all informations (as compositions, operating conditions, models, options) for all streams which you need to define, to access the Stream editor from Excel Properties menu select Edit Properties
The Stream editor includes several pages, from the first page you can select a stream (Properties can store all the streams required to define a medium size plant) solve a series of flash operations and see the resulting compositions in the different phases, in this page select the stream you wish to define, for example the first.
In the second page you can define a new composition or modify an existing composition, in this example we define C1 0.7 CO2 0.15 H2S 0.15 as molar fractions
In the third page you can define the package (thermodynamic models and related options) , here we define API Soave Redlick Kwong.
The fourth page provides access to BIP (Binary Interaction Parameters) for the different models, you can enter specific values or click on "Load BIPs" button to get the predefined BIPs from databank.
Finally we must save the new data, in the first page click on "Save" button, note that you can redefine the name of the stream as you wish (editing the cell near the button "Save"), you can define / modify many streams following the procedure described.
Once defined the stream you may wish to define the units which we wish to utilize in our problem, in stream editor go then to the "Units" dialog
here you can select the units which you need for a specific problem, in this example for the pressure (first row) select Bar.a , notice that unit for temperature is K (but you can set the units which you prefer) then click on Ok button to accept new values and leave the Properties editor.
Now you are ready to use Properties for calculating all the properties which you need, however there is still a last thing to do if you do not wish to lose all data when leaving a Excel page, precisely to save data to a file, to save data to a file from Excel Properties menu select "Save a Archive"
then select the file "def.ppp" if you wish that Properties utilizes this data as default (this is the normal , recommended option), differently set a different name (you can for example define different names for different projects) but you will need to load that specific Archive before to make calcs for that project and since Excel reloads Properties with any new page this may result tedious...
Properties saves on the file also the units of measurement so you can define different streams and different units in different projects.
Now you can calculate all the properties which you need with the units which you prefer for all the streams defined in that project.
Second step: calculate properties in Excel cells.
Suppose we wish to calculate the densities for the mixture defined in stream 1 directly in the cells, in B3 we enter the macro =EStrLD(1,B1,B2) , for calculating liquid density of stream 1 at temperature specified in B1 and pressure specified in B2 ,in B4 we enter the macro =EStrGD(1,B1,B2) for calculating the gas density and in B5 the macro =EStrLf(1,B1,B2) for calculating the liquid fraction
In B1 we enter 200 as temperature (remember we have K as unit) and in B2 we enter 5 as pressure (remember we have set Bar.a as unit), densities are in Kg/m3 , notice that when you change B1 or B2 Prode Properties recalculates these values. Now you can modify the stream 1 (changing the list of components, the compositions or models) or the units of measurement and Prode Properties will calculate the value of densities and liquid fraction accordingly, in this way is very easy with Excel to solve many different problems leaving to Prode Properties the task to calculate all properties for pure fluids and mixtures.
Calculate properties in Matlab.
From Matlab command line you can call the methods in Prode Properties by typing the names, for example to calculate cp/cv at specified conditions
>> ans = 1.3211
or, to calculate the speed of sound for vapor phase at same conditions
>> ans = 374.1625
in Matlab (as In Excel) you can access the Properties editor from menu associated with the figure.
Herebelow a short list of the properties available, read the operating manual for additional information.
Third step: calculate tables of values and print graphs.
Finally we will see how to calculate and graph tables of values in a range of temperatures for many different properties (liquid fraction, cp, cv, density, viscosity, thermal conductivity, speed of sound) for both gas and liquid phases, for doing this we will use a predefined Excel page, from Excel menu File->open , in Excel folder (in Prode Properties installation) select the file props.xls
If you wish you can modify the stream composition or the units of measurement , in that case, as before from Properties menu access the Properties editor and modify the previous data. Then enter (in the proper units) the desired range of temperatures (cells B2-B3) and the operating pressure (cell B4) and click on compute button to calculate the data, Prode Properties will print the values with the desired units of measuremebt.
In the same page there are a series of graphs which show the different properties at different operating conditions.
As you see Properties is a useful tool in everyday work, you can calculate rigorously, easily and quickly many different properties, you can set preferred units, you can define and save many different streams.
Technical features overview (Windows version)