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


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Application example : vaporliquidliquid phase envelope
Prode Properties can calculate different types of phase diagrams
 vaporliquid phase envelope / phase diagram.
 vaporliquidliquid phase envelope / phase diagram.
 vaporliquidsolid phase envelope / phase diagram.
Prode Properties allows to create the diagrams directly in Excel, Matlab, Mathcad, Prime or any compatible application including custom software.
Definitions
 Dew Point, given a equilibrium pressure the Dew Point Temperature is the maximum temperature in VLE area
 Bubble Point, given a equilibrium pressure the Bubble Point Temperature is the minimum temperature in VLE area
 CrcondenBar, CricondenBar Pressure is the maximum pressure in VLE area
 Crcondentherm, Cricondentherm temperature is the maximum temperature in VLE area
Step by Step instruction to create a phase diagram with Excel / Matlab / Mathcad
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: generate a vaporliquidliquid phase envelope in Excel.
For generating the phase envelope we’ll use a predefined Excel page distributed with Prode Properties, from Excel menu File>open , in Excel folder (Prode Properties installation) select the file phasenv.xls
This page contains a little VBA code to tranfer the calculated equilibrium values (for the different vaporliquid, liquidliquidvapor, vaporliquidliquid lines) from Prode Properties to Excel, if required you can easily modify the code for printing a series of lines with specified liquid or vapor fraction. To print a phase envelope you must define the stream (we select the first stream, which we defined with composition C1 0.7 CO2 0.15 H2S 0.15 , SRK as model and multiphase vapor+liquid option, the multiphase option instructs the procedure to generate a vaporliquidliquid phase envelope) we specify 0.3 value for liquid fraction, finally click on the button "calculate phase diagram". Properties does all the work and the calculated equilibrium points including critical points, cricondentherm and cricondenbar are printed in Excel page for your analysis.
The phase envelope for this mixture shows a three phase area (notice the second line near the liquidliquidvapor bubble line and the third liquidvaporliquid line
The calculated values for Critical Points, CricondenBar and CricondenTherm are available in Excel. Note that Prode Properties calculates the TRUE critical points (not the estimated values), Prode Properties includes a proprietary procedure based on Gibbs minimization method. the procedure allows to specify any value (from 0 dew line to 1 bubble line) for phase fractions, herebelow the example of a line with 0.05 liquid fraction.
The VaporLiquidLiquid phase envelope constitutes the ideal tool to investigate the phase equilibria for mixtures of hydrocarbons + water The example shows the phase envelope for a 12 components (hydrocarbons + water) mixture, notice the large three phase area where liquid water is present.
Note that even simple compositions can show a complex behaviour, herebelow is the example of the mixture with composition Methane 0.9 H2S 0.1 model API Soave Redlick Kwong. The bubble line is a three phase (liquidliquidvapor) line, a vaporliquid line connects the end of the liquidliquidvapor line with critical point, the dew line doesn't stop at critical point but continues, the blue line shows a liquid fraction of 0.05
Note that Prode Properties includes methods for calculating critical points, CricondenBar and CricondenTherm in Excel cells, see the paragraph "Methods for thermodynamic calc’s" in operating manual for the details.
 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).
To get the value of critical pressure 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.
The phase envelope for this mixture (Methane 0.999 nButane 0.001) 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 temperature (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 13 along the dew line)
For additional infrmation about how to calculate equilibrium points go to the page Dew Points Natural Gas Hydrocarbons
Print a phase envelope in Matlab.
For calculating and printing the phase envelope we’ll use a predefined script distributed with Prode Properties, in Matlab command line type >>phaseenvelope(1) where (1) is the number of stream.
Prode Properties will calculate the phase envelope and print the result on Matlab, if you wish to obtain additional properties as cricondentherm, cricondenbar or critical points just enter the name of Properties method in Matlab, for example >>StrPc(1) will return the true critical pressure of stream 1.
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
 Regular
 Wilson
 NRTL
 UNIQUAC
 UNIFAC
 SoaveRedlichKwong (standard and extended version with parameters calculated for best fitting of vapor pressure, density and enthalpy)
 PengRobinson (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)
 LeeKesler (Plocker) LKP
 Cubic Plus Association (SRK and PR variants)
 Hydrates (Cubic Plus Association, Van Der WaalsPlatteeuw)
 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 WaalsPlatteeuw 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
 HNEDS, Homogeneous Nonequilibrium
 NHNE, Nonhomogeneous Nonequilibrium
 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 / vaporliquidsolid fugacity plus derivatives vs. temperature pressure composition
 gas / vaporliquidsolid enthalpy plus derivatives vs. temperature pressure composition
 gas / vaporliquidsolid entropy plus derivatives vs. temperature pressure composition
 gas / vaporliquidsolid 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 vaporliquidsolid, 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 vaporliquidsolid, includes adiabatic flash
 Flash at given enthalpy (H) and T multiphase vaporliquidsolid, includes adiabatic flash
 Flash at given entropy (S) and P multiphase vaporliquidsolid, includes isentropic flash
 Flash at given entropy (S) and T multiphase vaporliquidsolid, includes isentropic flash
 Flash at given volume (V) and P multiphase vaporliquidsolid, includes isochoric flash
 Flash at given volume (V) and T multiphase vaporliquidsolid, includes isochoric flash
 Flash at given volume (V) and H multiphase vaporliquidsolid
 Flash at given volume (V) and S multiphase vaporliquidsolid
 Flash at given volume (H) and S multiphase vaporliquidsolid
 Rigorous (True) critical point plus Cricondentherm and Cricondenbar
 Complete set of properties for different states
 gas density
 vapor density
 liquid density
 solid density
 gas Isobaric specific heat (Cp)
 vapor Isobaric specific heat (Cp)
 liquid Isobaric specific heat (Cp)
 gas Isochoric specific heat (Cv)
 vapor Isochoric specific heat (Cv)
 liquid Isochoric specific heat (Cv)
 gas cp/cv
 liquid cp/cv
 Gas heating value
 Gas Wobbe index
 Gas Specific gravity
 gas Joule Thomson coefficients
 vapor Joule Thomson coefficients
 liquid Joule Thomson coefficients
 gas Isothermal compressibility
 vapor Isothermal compressibility
 liquid Isothermal compressibility
 gas Volumetric expansivity
 vapor Volumetric expansivity
 liquid Volumetric expansivity
 gas Speed of sound
 vapor Speed of sound
 liquid Speed of sound
 vapor + liquid (HEM) Speed of sound
 gas Viscosity
 vapor Viscosity
 liquid Viscosity
 gas Thermal conductivity
 vapor Thermal conductivity
 liquid Thermal conductivity
 gas compressibility factor
 vapor compressibility factor
 liquid Surface tension
Typical applications
 Fluid properties in Excel, Matlab and other Windows and UNIX (**) applications
 Thermodynamics, physical, thermophysical properties
 Phase envelope for hydrocarbons, natural gas mixtures
 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


Perspective users are invited to contact Prode for discussing the applications of Prode Properties


