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Prode Properties
Properties of pure fluids and mixtures,
multiphase equilibria, process simulation.

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Properties Documentation

Excel application example : dew point, bubble point, cricondentherm, cricondenbar, critical point

Prode Properties has specific methods which permit to calculate dew points, bubble points, equilibrium points at specified phase fraction (vapor, liquid, solid **) and pressure (or temperature), typical applications include hydrocarbons dew point (HDP, HCDP), cricondentherm, cricondenbar of natural gas mixtures from gas analysis.
Prode Properties can calculate up to 5 equilibrium points along a line with specified phase fraction, in addition there are specific methods for calculating directly Cricondentherm, CricondenBar and Critical points. With Prode Properties you can do this in Excel, Matlab or any compatible application including custom software, this example shows how to use these methods in Excel.

Before to use Properties from Excel you must load the add-in (file properties.xla) which instructs Excel about Prode Properties library, you need to go through this procedure only once, to load the add-in open Excel and choose the Tools/Add-ins menu item, you’ll see a list of add-ins, some checked, some not checked. If Prode Properties isn’t listed (and it won’t be unless you went through this procedure earlier) browse for the properties.xla file in \PROPERTIES\Excel folder then back your way out. Now Prode Properties should be listed in the list of add-ins, its box should be checked, and you should see a Prode Properties menu in Excel. If you close Excel and then reopen it Prode Properties menu must still be there. Once you installed the add-in you'll be able to access Prode Properties from within Excel.

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 calc's 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.

Prode Properties includes methods for calculating critical points and equilibrium points at specified conditions, see the paragraph “Methods for thermodynamic calc’s” in operating manual for the details.

  • methods LfPF() and LfTF() are based on a liquid fraction specification, they returns the first point (along the specified liquid fraction line) at the specified pressure (or temperature)
  • methods PfPF() and PfTF() can accept a gas, liquid, solid ** fraction as specification, they can calculate up to 5 points (at specified pressure or temperature) along the line with specified phase fraction
  • methods StrPc() and StrTc() returns the critical pressure (or temperature) of the nth (from 1 to 5) critical point found.
  • methods StrCBp() and StrCBt() returns the pressure (or temperature) of the CricondenBar (the equilibrium point with maximum pressure).
  • methods StrCTp() and StrCTt() returns the pressure (or temperature) of the CricondenTherm (the equilibrium point with maximum temperature).

Suppose we wish to calculate a equilibrium point near the critical point for the mixture defined in stream 1, to get the first critical point pressure we enter the macro =StrPc(1,1) where (1,1) refers to the stream 1 and first critical point detected, we enter this macro in B1, in B2 we enter the macro =StrTc(1,1) to calculate the critical temperature in the same way, in cells B3 and B4 we enter the macros = StrCBp(1) for CricodenBar pressure and = StrCTt(1) for CricodenTherm temperature, with this data we have a plot of the whole phase envelope.

Note that Prode Properties includes methods to plot the phase envelope directly in Excel, go to the page Phase envelope to investigate this option.

Now we wish to calculate two equilibrium points on the dew line (the red line in phase envelope) at pressure of 89 Bar.a (remember that maximum value is the CricondenBar pressure which is 89.09 Bar.a), we use the method

double t = PfPF(integer stream, double p, double pf, int state, int n)

In cell B1 we define a value for the equilibrium pressure (89 Bar.a) , then in cells B2, B3 we enter the macros

=PfPF(1,B1,0,1,1)

=PfPF(1,B1,0,1,2)

where the first value (1) is the stream , the second (cell B1) represents the pressure, the third (0) is the phase fraction (with 0 we specify 0% liquid or a point on dew line, the same would be by setting the state as gas and phase fraction as 1.0) the fourth (1) is the state (in Properties 0 = gas, 1 = liquid, 2 = solid) and the last is the required position (we require the points 1-2 along the dew line)

If we change the value of equilibrium pressure the procedure calculates the new equilibrium temperatures

Now a more elaborate example, we define a stream with the mixture Methane 0.999 n-Butane 0.001

  • from Properties menu select Edit Properties
  • in Stream->Operating dialog we select the stream number 2 and define the name “Mixture 2”
  • then we select Stream->Components dialog and define a composition of two components with following molar fractions Methane 0.999 n-Butane 0.001
  • in Stream->Models dialog we define the Peng Robinson (PR-VDW) for all properties
  • then we can edit BIPs, we can input data or load from database
  • in Stream->Operating dialog we click on Save button to save the stream data
  • Now the stream 2 has been defined

The phase envelope for this mixture shows up to four saturation point pressures at the same temperature

Observe the dew line, the red line below the critical point, there are up to three different equilibrium points at the same temperature (the area around 190 K), if you add the saturation point on the bubble line (black line) we have a total of four saturation point pressures at a given temperature, to calculate the points on the dew line we use the method:

double p = PfTF(integer stream, double t, double pf, int state, int n)

In cell B1 we define a value for the equilibrium temeperature (190.208 K) , then in cells B2, B3, B4 we enter the macros

=PfTF(2,B1,0,1,1)

=PfTF(2,B1,0,1,2)

=PfTF(2,B1,0,1,3)

where the first value (2) is the stream which we defined, the second (cell B1) represents the temperature, the third (0) is the phase fraction (with 0 we specify 0% liquid or a point on dew line, the same would be by setting the state as gas and phase fraction as 1.0) the fourth (1) is the state (in Properties 0 = gas, 1 = liquid, 2 = solid) and the last is the required position (we require the points 1-3 along the dew line)

If we change the temperature the procedure recalculates equilibrium pressures

you may wish to test the method LfTF(), enter the macro

=LfTF(2,B1,0)

where 2 is the stream, B1 represents the temperature and 0 is the (liquid) phase fraction, notice that you’ll get the same values as for the first equilibrium point in PfTF(), by changing the specification we can use the method LfTF() to calculate the point on bubble line

=LfTF(2,B1,1)

where 1 is the specification (100% liquid) for a point on the bubble line , but of course you get the same result with the method:

=PfTF(2,B1,1,1,1)

where the third value (1) is the phase fraction (with 1 we specify a 100% fraction) the fourth (1) is the state (in Properties 0 = gas, 1 = liquid, 2 = solid) and the last is the required position for the point.

Prode Properties calculates thermophysical properties of pure fluids and mixtures, herebelow a short list of the properties available, read the operating manual of Prode Properties for additional information.

  • Phase fraction (vapor, liquid, solid)
  • (True) critical point pressure of mixtures
  • (True) critical point temperature of mixtures
  • Cricondentherm temperature of mixtures
  • Cricondentherm pressure of mixtures
  • CricondenBar temperature of mixtures
  • CricondenBar pressure of mixtures
  • Enthalpy of gas / vapor phase
  • Enthalpy of liquid phase
  • Enthalpy of solid phase
  • Entropy of gas / vapor phase
  • Entropy of liquid phase
  • Entropy of solid phase
  • Density of gas / vapor phase
  • Density of liquid phase
  • Density of solid phase
  • Isobaric specific heat (Cp) of gas / vapor phase
  • Isobaric specific heat (Cp) of liquid phase
  • Isochoric specific heat (Cv) of gas / vapor phase
  • Isochoric specific heat (Cv) of liquid phase
  • Gas heating value
  • Gas Wobbe index
  • Gas Specific gravity
  • Joule Thomson coefficients of gas / vapor phase
  • Joule Thomson coefficients of liquid phase
  • Isothermal compressibility of gas / vapor phase
  • Isothermal compressibility of liquid phase
  • Speed of sound in gas / vapor phase
  • Speed of sound in liquid phase
  • Viscosity of gas / vapor phase
  • Viscosity of liquid phase
  • Thermal conductivity of gas / vapor phase
  • Thermal conductivity of liquid phase
  • liquid Surface tension

Technical features overview (Windows version)

  • Entirely written in C++, Microsoft MFC provides Microsoft Windows functionalities.
  • Up to 100 different streams with up to 50 components per stream (user can redefine)
  • Several compilations of chemical data and BIPs are available, the user can add new components and BIPs
    • free proprietary compilation with data on 1000+ chemicals
    • flexible database format works with all majour standards including DIPPR.
  • Comprehensive set of thermodynamic models, base version includes Regular, Wilson, NRTL, UNIQUAC, UNIFAC, Soave-Redlich-Kwong, Peng-Robinson, Benedict Webb Rubin (Starling) BWRS, Steam Tables IAPWS 95, Lee-Kesler (Plocker) LKP , AGA 8 (1992), models as PC-SAFT etc. are available on request.
  • Selectable units of measurement
  • Procedure for fitting BIP to measured VLE / LLE data points (data regression)
  • Procedure for fitting BIP to VLE values calculated with UNIFAC
  • Functions for simulating operating blocks (mixer, gas separator, liquid separator) **
  • Functions for accessing component data in database (the user can define mixing rules)
  • gas / vapor-liquid-solid fugacity plus derivatives vs. temperature pressure composition
  • gas / vapor-liquid-solid enthalpy plus derivatives vs. temperature pressure composition
  • gas / vapor-liquid-solid entropy plus derivatives vs. temperature pressure composition
  • gas / vapor-liquid-solid molar volume plus derivatives vs. temperature pressure composition
  • Flash at Bubble and Dew point specifications and P (or T)
  • Flash at given temperature (T) and pressure (P) multiphase vapor-liquid-solid
  • Flash at given liquid fraction (vaporization ratio) and P (or T)
  • Flash at given enthalpy (H) and P multiphase vapor-liquid-solid **
  • Flash at given entropy (S) and P multiphase vapor-liquid-solid **
  • Rigorous (True) critical point plus Cricondentherm and Cricondenbar
  • gas / vapor-liquid-solid density
  • gas / vapor-liquid Isobaric specific heat (Cp) and Isochoric specific heat (Cv) plus cp/cv
  • Gas heating value
  • Gas Wobbe index
  • Gas Specific gravity
  • gas / vapor-liquid Joule Thomson coefficients
  • gas / vapor-liquid Isothermal compressibility
  • gas / vapor-liquid Speed of sound
  • gas / vapor-liquid Viscosity
  • gas / vapor-liquid Thermal conductivity
  • gas / vapor compressibility factor
  • liquid Surface tension
  • ** some methods are available in extended / custom versions

Typical applications

  • Fluid properties in Excel, Matlab and other Windows and UNIX (**) applications
  • Thermodynamics, physical, thermophysical properties
  • Process simulation
  • Heat / Material Balance
  • Process Control
  • Process Optimization
  • Equipment's Design
  • Separations
  • Instrument's Design
  • Realtime applications
  • petroleum, refining, natural gas, hydrocarbon, chemical, petrochemical, pharmaceutical, air conditioning, energy, mechanical industry
Prode Engineering Perspective users are invited to contact Prode for discussing the applications of Prode Properties