Properties of pure fluids and mixtures,
multiphase equilibria, process simulation
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Excel / Matlab application example : multiphase vapor liquid equilibria
With the base version of Prode Properties you can calculate multiphase vapor liquid equilibria plus a limited number of vapor liquid solid equilibria cases, this Excel application example shows how to use Properties to calculate the multiphase flash operation and get the results directly in Excel pages.
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 multiphase equilibria.
Multiphase analysis permits to discover instabilities and formation of new phases where the standard procedure fails, we start by examining the results of the standard two-phases flash procedure, from the Stream editor in Stream->Operating select the first stream (which we defined with composition C1 0.7 CO2 0.15 H2S 0.15 and API SRK as model) then in Stream->Models you see that as default Multiphase equilibria was set to "No multiphase, only two-phases" (this is the default because multiphase is much slower)
In Stream->Operating you can solve a series of predefined operations, select the first stream as Feed and Operation and TP-VL as flash operation, then enter 150 K and 10 Bar.a as specifications, then click on the button "Compute", as result the procedure detects one liquid phase, notice that you see the results of flash operations directly in the stream's editor, you can set different specifications and get immediately the results.
To perform a multiphase vapor-liquid flash select the TP-VLL operation, set as before the specifications as 150 K and 10 Bar.a and click on Compute, now the procedure detects three liquid phases.
You can obtain the same results directly in Excel by loading the file "multiphase.xls" (distributed with Properties) and following the same procedure, to instruct Prode Properties to perform a multiphase flash (the default is the two phases flash) go in Stream->Models and change the option for multiphase to Multiphase vapor-liquid and the Multiphase initialization to Extended tests, then in Stream->Operating Save the stream (remember to click on "Save" button when you change something in the stream).
Calculate properties in Matlab.
From Matlab command line you can call the methods in Prode Properties by typing the names, for example to obtain the different phase fractions calculated by procedure
>> = StrPf(1,1)
>> ans = 0.8036
>> = StrPf(1,2)
>> ans = 0.1258
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.
- 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
- Cloud point temperature of mixtures
- Cloud point 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
- Volumetric expansivity of gas / vapor phase
- Volumetric expansivity of liquid phase
- Speed of sound in gas / vapor phase
- Speed of sound in liquid phase>
- Speed of sound in gas+liquid (mixed) 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
- Proprietary compilation with data on more than 1500 chemicals and 25000 BIPs
- flexible database format (support for up to 30 different correlations) works with all majour standards including DIPPR.
- Comprehensive set of thermodynamic models, base version includes
- Soave-Redlich-Kwong (standard and extended version with parameters calculated for best fitting of vapor pressure, density and enthalpy)
- Peng-Robinson (standard and extended version with parameters calculated for best fitting of vapor pressure, density and enthalpy)
- Benedict Webb Rubin (Starling) BWRS
- Steam Tables IAPWS 95
- ISO 18453 (GERG 2004)
- ISO 20765 (AGA model)
- Lee-Kesler (Plocker) LKP
- Cubic Plus Association (SRK and PR variants)
- Hydrates (Cubic Plus Association, Van Der Waals-Platteeuw)
- additional models as Pitzer, NRTL for electrolyte solutions, PC SAFT (with association contribute), GERG (2008) etc. available in extended versions.
- van der Waals and complex mixing rules (Huron Vidal, Wong Sandler etc.)
- Base and Extended (to fit experimental data) EOS parameters.
- Selectable units of measurement
- Procedure for solving single phase, two phase, multiphase fluid flow
- Procedure for solving staged columns
- Rigorous solution of distillation columns, fractionations, absorbers, strippers...
- Procedure for calculating temperature / pressure formation of gas hydrates
- hydrate phase equilibria based on Cubic Plus Association and Van Der Waals-Platteeuw models
- Procedure for solving polytropic compression with phase equilibria
- Huntington method for gas phase
- Proprietary method for solving a polytropic process with phase equilibria
- Procedure for solving isentropic nozzle (safety, relief valve with single and two phase flow)
- HEM, Homogeneous Equilibrium
- HNE-DS, Homogeneous Non-equilibrium
- NHNE, Non-homogeneous Non-equilibrium
- Procedure for simulating fluid flow in piping (pipelines) with heat transfer
- Beggs and Brill and proprietary methods for single phase and multiphase fluid flow with heat transfer
- Procedure for fitting BIP to measured VLE / LLE / SLE 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, isothermal flash
- Flash at given phase fraction and P (or T), solves up to 5 different points
- Flash at given enthalpy (H) and P multiphase vapor-liquid-solid, includes adiabatic flash
- Flash at given enthalpy (H) and T multiphase vapor-liquid-solid, includes adiabatic flash
- Flash at given entropy (S) and P multiphase vapor-liquid-solid, includes isentropic flash
- Flash at given entropy (S) and T multiphase vapor-liquid-solid, includes isentropic flash
- Flash at given volume (V) and P multiphase vapor-liquid-solid, includes isochoric flash
- Flash at given volume (V) and T multiphase vapor-liquid-solid, includes isochoric flash
- Rigorous (True) critical point plus Cricondentherm and Cricondenbar
- Complete set of properties for different states
- 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 Volumetric expansivity
- gas / vapor-liquid Speed of sound
- gas / vapor-liquid Viscosity
- gas / vapor-liquid-solid Thermal conductivity
- gas / vapor compressibility factor
- liquid Surface tension
- 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
- Instrument's Design
- Realtime applications
- petroleum, natural gas, hydrocarbon, chemical, petrochemical, pharmaceutical, air conditioning, energy, mechanical industry
Perspective users are invited to contact Prode for discussing the applications of Prode Properties