Lee-Kesler-Plöcker

Corresponding-states equation of state of Lee, Kesler and Plöcker: two Benedict-Webb-Rubin reference fluids interpolated with the acentric factor, for the phase equilibrium and the enthalpy of hydrocarbon mixtures and light gases.

DWSIM.Thermodynamics.PropertyPackages.LKPPropertyPackage
Assembly DWSIM.Thermodynamics.dll · Object ← PropertyPackage ← LKPPropertyPackage
Name in the flowsheet Lee-Kesler-Plöcker · FluentAPI PropertyPackages.LeeKeslerPlocker

Scope

Lee-Kesler-Plöcker (LKP) is a corresponding-states model for hydrocarbon mixtures and light gases: natural gas, gas processing, refinery light ends, and the compression, expansion and refrigeration of these streams, where the enthalpy has to be right. The DWSIM property package selection guide lists it, with Chao-Seader and Grayson-Streed, for systems with a high hydrogen content.

The mixture is represented by two reference fluids, a simple fluid (acentric factor 0) and a heavy reference fluid (n-octane, acentric factor 0.3978), each described by a Benedict-Webb-Rubin equation in reduced temperature and volume. The compressibility factor and the fugacity coefficient of the mixture are interpolated between the two fluids with the mixture acentric factor. The pseudo-critical constants of the mixture come from the mixing rules of Plöcker, Knapp and Prausnitz:

• a pair critical volume v_c,jk = (V_c,j^1/3 + V_c,k^1/3)³/8 and a pair critical temperature t_c,jk = (T_c,j T_c,k)^1/2 k_jk;
• V_cm and T_cm as double sums over the pairs, the acentric factor as the mole-fraction average, and P_cm = (0.2905 - 0.085 ω_m) R T_cm / V_cm.

The binary parameter k_jk multiplies the pair critical temperature, so 1 means no correction. The package ships the k_ij of Plöcker, Knapp and Prausnitz (1978) for the common pairs of hydrocarbons with each other and with N₂, CO₂, H₂S, H₂ and CO. A pair missing from the table takes an estimate when one compound is a hydrocarbon (or a petroleum fraction) and the other a lighter hydrocarbon, N₂, CO, CO₂ or H₂S: k_jk = 1 + 0.2802 ln(T_c2/T_c1) ln(V_c2/V_c1) - 0.0561 ln(T_c2/T_c1) for hydrocarbons, N₂ and CO when T_c2/T_c1 is at least 1.3, a correlation of its own for CO₂, and the CO₂ value less 0.027 for H₂S. They were fitted to the table (rms 0.011) and to k_jk regressed from about 800 solubility points; over 180 of those points the gas solubility deviates 23.8 % on average (Peng-Robinson 27.5 %). Every other pair takes 1. The parameter editor shows the estimates, and every value can be edited or fitted with the data regression tool (default bounds 0.5 to 4); table values and values set by the user are kept.

Hydrogen. The hydrogen k_ij of the table go with quantum-corrected critical constants, so hydrogen enters the mixing rules with the effective constants of Gunn, Chueh and Prausnitz (1966): T_c = 43.6/(1 + 21.8/(M T)) K, P_c = 20.5/(1 + 44.2/(M T)) atm, V_c = 51.5/(1 - 9.91/(M T)) cm³/mol and ω = 0. A hydrogen pair missing from the table takes k_ij = 0.2036 + 0.002246 T_c + 0.8364 ω + 1.2111 V_c^1/3 from the partner's constants (K, m³/kmol), fitted to the table pairs and to solubility data in n-dodecane, benzene, toluene, cyclohexane and methylcyclohexane. Values in the table or set by the user are kept. Hydrogen solubility against data:

System	Data	LKP
n-hexane, 344 K, 3.36 MPa	0.0286	0.0253
n-hexane, 378 K, 15.1 MPa	0.143	0.140
n-dodecane, 344 K, 5.8 MPa	0.0505	0.0499
benzene, 303 K, 4.6 MPa	0.0127	0.0134
toluene, 303 K, 4.4 MPa	0.0146	0.0128

The phase equilibrium uses the LKP fugacity coefficients of both phases. Enthalpy, entropy and heat capacities of vapor and liquid are Lee-Kesler departure functions added to the ideal-gas values, and the vapor density follows from the LKP compressibility factor. The liquid density comes from the experimental data of each compound or the Rackett and COSTALD correlations; viscosity, thermal conductivity and surface tension use the same correlations as the cubic equations of state.

DWSIM supplies analytical temperature derivatives of the fugacity coefficients for this package, which the flash and the column solvers use; the composition derivative is part analytical, part finite difference.

Limitations

• Every compound needs T_c, P_c, V_c and ω. For polar compounds the selection guide recommends PRSV2 or an activity coefficient model such as NRTL.
• The model is slower than a cubic equation of state, and the guide notes that it is very sensitive to the values of the interaction parameters.
• The liquid density is a correlation, independent of the equation of state.
• The estimates are poor for bicyclic naphthenes (methane or CO₂ in decalin, solubility 50 % to more than 100 % high), for N₂ and CO with aromatics (30 to 40 % low) and for H₂S with C10 and heavier, where no data were available; the hydrogen estimate is not verified beyond n-dodecane.
• The k_jk do not depend on temperature.
• A flowsheet saved after its parameter editor was opened in an earlier version stored 1 for the pairs missing from the table and keeps that value.

Example

This code runs on every build of this site, and the output below is what it printed.

Python

def case(package):
    fs = (Flowsheet.Create("LKPExample")
          .WithCompounds("Methane", "Ethane", "Propane", "N-butane", "N-pentane")
          .WithPropertyPackage(package))
    # a rich natural gas that condenses partly at 5 C and 30 bar
    gas = (fs.AddMaterialStream("Gas")
           .At(Q.Celsius(5.0), Q.Bar(30.0))
           .SetCompoundMolarFlow("Methane", 70.0)       # mol/s
           .SetCompoundMolarFlow("Ethane", 12.0)
           .SetCompoundMolarFlow("Propane", 10.0)
           .SetCompoundMolarFlow("N-butane", 5.0)
           .SetCompoundMolarFlow("N-pentane", 3.0))
    # methane compressed isothermally from 1 to 100 bar at 25 C: the enthalpy change is
    # the residual enthalpy at 100 bar
    low = (fs.AddMaterialStream("Methane 1 bar").At(Q.Celsius(25.0), Q.Bar(1.0))
           .SetCompoundMolarFlow("Methane", 1.0))
    high = (fs.AddMaterialStream("Methane 100 bar").At(Q.Celsius(25.0), Q.Bar(100.0))
            .SetCompoundMolarFlow("Methane", 1.0))
    fs.Solve()
    g, lo, hi = gas.Object, low.Object.Phases[0].Properties, high.Object.Phases[0].Properties
    return fs, [g.Phases[2].Properties.molarfraction, g.Phases[2].Properties.density,
                g.Phases[0].Properties.enthalpy, hi.enthalpy - lo.enthalpy, hi.density]

fs, lkp = case(PropertyPackages.LeeKeslerPlocker)
_, pr = case(PropertyPackages.PengRobinson)
_, gerg = case(PropertyPackages.GERG2008)

rows = ["Vapor fraction", "Vapor density, kg/m3", "Enthalpy of the gas, kJ/kg",
        "Methane 1 to 100 bar, dh, kJ/kg", "Methane at 100 bar, kg/m3"]
print(f"{'':32}{'LKP':>9}{'PR':>9}{'GERG-2008':>11}")
for name, a, b, c in zip(rows, lkp, pr, gerg):
    print(f"{name:32}{a:9.4g}{b:9.4g}{c:11.4g}")

Output

                                      LKP       PR  GERG-2008
Vapor fraction                       0.87   0.8794     0.8739
Vapor density, kg/m3                30.79    32.03      31.37
Enthalpy of the gas, kJ/kg         -165.5   -163.8     -165.6
Methane 1 to 100 bar, dh, kJ/kg    -99.15   -109.9     -100.5
Methane at 100 bar, kg/m3           75.77    76.41      75.99

DWSIM 10.2.11.0, generated 2026-10-08.

Property methods

How the package calculates each property, as it reports it in PropertyMethodsInfo (the property package editor shows the same list).

Property	Method
Vapor fugacity	Lee-Kesler-Plöcker EOS
Liquid fugacity	Lee-Kesler-Plöcker EOS
Vapor enthalpy, entropy, Cp/Cv	Lee-Kesler-Plöcker EOS
Liquid enthalpy, entropy, Cp/Cv	Lee-Kesler-Plöcker EOS
Vapor density	Lee-Kesler-Plöcker EOS
Liquid density	Experimental / Rackett / COSTALD
Vapor viscosity	Experimental / Lucas / Jossi-Stiel-Thodos
Liquid viscosity	Experimental / Letsou-Stiel
Vapor thermal conductivity	Experimental / Ely-Hanley
Liquid thermal conductivity	Experimental / Latini
Surface tension	Experimental / Brock-Bird
Solid density	Experimental Data / User-Defined
Solid enthalpy, entropy, Cp/Cv	Experimental Solid Cp / From Liquid Phase Enthalpy + Enthalpy of Fusion

Default flash algorithm: Universal.

Configuration saved with the flowsheet

The package writes its settings to the simulation file (SaveData) and reads them back on load (LoadData). The elements below are the ones this package adds to those of every property package, as written for the example.

Element	Content in the example	What it holds
InteractionParameters	10 InteractionParameter entries (Compound1, Compound2, Value)	kij of the pairs of the flowsheet compounds (Value), the factor on the pair pseudo-critical temperature; from the package table (lkp_ip.dat) or entered in the editor, 1 for a pair without a value

First InteractionParameter of InteractionParameters in the example

<InteractionParameter Compound1="Methane" Compound2="Ethane" Value="1.052" />

Settings common to every property package, as saved for the example

Element	Value
Type	DWSIM.Thermodynamics.PropertyPackages.LKPPropertyPackage
ComponentName	Lee-Kesler-Plöcker
ComponentDescription
Tag	Lee-Kesler-Plöcker
UseHenryConstants	true
AutoEstimateMissingNRTLUNIQUACParameters	true
UseImmiscibleListForLiquid2InitialEstimates	true
SingleCompoundCheckThreshold	0.99999
OverrideKvalFugCoeff	false
OverrideEnthalpyCalculation	false
OverrideEntropyCalculation	false
LiquidDensityCalculationMode_Subcritical	Rackett_and_ExpData
LiquidDensityCalculationMode_Supercritical	Rackett_and_ExpData
LiquidDensity_CorrectExpDataForPressure	true
LiquidDensity_UsePenelouxVolumeTranslation	true
LiquidViscosityCalculationMode_Subcritical	ExpData
LiquidViscosityCalculationMode_Supercritical	Letsou_Stiel
LiquidViscosity_CorrectExpDataForPressure	true
LiquidViscosity_MixingRule	MoleAverage
VaporPhaseFugacityCalculationMode	Ideal
SolidPhaseFugacityCalculationMethod	FromLiquidFugacity
SolidPhaseFugacity_UseIdealLiquidPhaseFugacity	false
SolidPhaseEnthalpy_UsesCp	false
EnthalpyEntropyCpCvCalculationMode	LeeKesler
LiquidEnthalpyEntropyCpCvCalculationMode_EOS	EOS
LiquidFugacity_UsePoyntingCorrectionFactor	true
ActivityCoefficientModels_IgnoreMissingInteractionParameters	false
IgnoreVaporFractionLimit	false
IgnoreSalinityLimit	false
CalculateAdditionalMaterialStreamProperties	true
FlashCalculationApproach	NestedLoops
DisplayMissingCompoundPropertiesWarning	false
ForcedSolids	[]
PropertyOverrides	{}
FlashSettings	36 Setting entries

Learn more

• User guide

  ---

  • Lee-Kesler
  • Mixture pseudo-critical rules
  • Compressibility and fugacity coefficient
  • Property Package Selection Guide

• Used with

  ---

  • Compressor
  • Expander
  • Valve
  • Separator Vessel
  • Heat Exchanger

API members

Public members declared by this class. Inherited members are documented on the base classes.

Constructors

LKPPropertyPackage()

C#VB.NET

public LKPPropertyPackage()

Public Sub New()

LKPPropertyPackage(bool)

Parameter	Type	Description
comode	Boolean

C#VB.NET

public LKPPropertyPackage(bool comode)

Public Sub New(comode As Boolean)

Properties

DisplayDescription

C#VB.NET

public override string DisplayDescription { get; }

Public Overrides ReadOnly Property DisplayDescription As String

DisplayName

C#VB.NET

public override string DisplayName { get; }

Public Overrides ReadOnly Property DisplayName As String

ImplementsAnalyticalDerivatives

C#VB.NET

public override bool ImplementsAnalyticalDerivatives { get; }

Public Overrides ReadOnly Property ImplementsAnalyticalDerivatives As Boolean

MobileCompatible

C#VB.NET

public override bool MobileCompatible { get; }

Public Overrides ReadOnly Property MobileCompatible As Boolean

Methods

AcidGasKijEstimate(bool, double, double): kij of carbon dioxide, or of hydrogen sulfide when H2S is true, with a hydrocarbon of critical temperature Tc (K)...

kij of carbon dioxide, or of hydrogen sulfide when H2S is true, with a hydrocarbon of critical temperature Tc (K) and critical volume Vc (m3/kmol), or zero when Tc is below that of carbon dioxide. With X = ln(Tc/304.21) ln(Vc/0.094): kij = 0.9276 + 0.10719 X + 0.04505 X^2 for carbon dioxide, 0.027 less for hydrogen sulfide. Carbon dioxide: fitted to the twelve hydrocarbon pairs of the table (rms 0.013) and to kij regressed from solubility data in n-C10, n-C12, n-C14, n-C16, n-C20, n-C28, toluene, m-xylene, cis-decalin and 1-methylnaphthalene (rms 0.028). Hydrogen sulfide: the offset is the mean difference to the isobutane pair of the table and to kij regressed from solubility data in propane, n-butane, n-pentane and n-heptane.

Parameter	Type	Description
H2S	Boolean
Tc	Double
Vc	Double

C#VB.NET

public static double AcidGasKijEstimate(bool H2S, double Tc, double Vc)

Public Shared Function AcidGasKijEstimate(H2S As Boolean, Tc As Double, Vc As Double) As Double

AUX_VAPDENS(double, double)

Parameter	Type	Description
T	Double
P	Double

C#VB.NET

public override double AUX_VAPDENS(double T, double P)

Public Overrides Function AUX_VAPDENS(T As Double, P As Double) As Double

AUX_Z(double[], double, double, PhaseName)

Parameter	Type	Description
Vx	Double[]
T	Double
P	Double
state	PhaseName

C#VB.NET

public override double AUX_Z(double[] Vx, double T, double P, PhaseName state)

Public Overrides Function AUX_Z(Vx As Double(), T As Double, P As Double, state As PhaseName) As Double

ConfigParameters()

C#VB.NET

public override void ConfigParameters()

Public Overrides Sub ConfigParameters()

DisplayEditingForm()

C#VB.NET

public override void DisplayEditingForm()

Public Overrides Sub DisplayEditingForm()

DW_CalcCompPartialVolume(Phase, double, double)

Parameter	Type	Description
phase	Phase
T	Double
P	Double

C#VB.NET

public override void DW_CalcCompPartialVolume(Phase phase, double T, double P)

Public Overrides Sub DW_CalcCompPartialVolume(phase As Phase, T As Double, P As Double)

DW_CalcCp_ISOL(Phase, double, double)

Parameter	Type	Description
Phase1	Phase
T	Double
P	Double

C#VB.NET

public override double DW_CalcCp_ISOL(Phase Phase1, double T, double P)

Public Overrides Function DW_CalcCp_ISOL(Phase1 As Phase, T As Double, P As Double) As Double

DW_CalcCv_ISOL(Phase, double, double)

Parameter	Type	Description
Phase1	Phase
T	Double
P	Double

C#VB.NET

public override double DW_CalcCv_ISOL(Phase Phase1, double T, double P)

Public Overrides Function DW_CalcCv_ISOL(Phase1 As Phase, T As Double, P As Double) As Double

DW_CalcdKdComposition(double[], double[], double, double, State, string): Composition (mole-number) derivative of the equilibrium K-values, d(K_i)/dn_j, with respect to the mole numbers of...

Composition (mole-number) derivative of the equilibrium K-values, d(K_i)/dn_j, with respect to the mole numbers of the phase indicated by withRespectTo (State.Liquid perturbs Vx, State.Vapor perturbs Vy), on a total-moles = 1 basis. Returns an (nc x nc) matrix. Base implementation is a finite difference; EOS/activity packages override it using the analytical d(ln phi)/dn (or d(ln gamma)/dx) building blocks.

Parameter	Type	Description
Vx	Double[]
Vy	Double[]
T	Double
P	Double
withRespectTo	State
type	String

C#VB.NET

public override double[,] DW_CalcdKdComposition(double[] Vx, double[] Vy, double T, double P, State withRespectTo, string type = "LV")

Public Overrides Function DW_CalcdKdComposition(Vx As Double(), Vy As Double(), T As Double, P As Double, withRespectTo As State, type As String = "LV") As Double(,)

DW_CalcdKdT(double[], double[], double, double, string)

Parameter	Type	Description
Vx	Double[]
Vy	Double[]
T	Double
P	Double
type	String

C#VB.NET

public override double[] DW_CalcdKdT(double[] Vx, double[] Vy, double T, double P, string type = "LV")

Public Overrides Function DW_CalcdKdT(Vx As Double(), Vy As Double(), T As Double, P As Double, type As String = "LV") As Double()

DW_CalcdLnFugCoeffdn(double[], double, double, State): Composition (mole-number) derivative of the natural logarithm of the fugacity coefficients, d(ln phi_i)/dn_j, for...

Composition (mole-number) derivative of the natural logarithm of the fugacity coefficients, d(ln phi_i)/dn_j, for the given phase, evaluated on a total-moles = 1 basis. Returns an (nc x nc) matrix. Base implementation is a finite difference in mole numbers; EOS/activity packages override this with the closed-form partial-molar expression.

Parameter	Type	Description
Vx	Double[]
T	Double
P	Double
st	State

C#VB.NET

public override double[,] DW_CalcdLnFugCoeffdn(double[] Vx, double T, double P, State st)

Public Overrides Function DW_CalcdLnFugCoeffdn(Vx As Double(), T As Double, P As Double, st As State) As Double(,)

DW_CalcdLnFugCoeffdT(double[], double, double, State): Temperature derivative of the natural logarithm of the fugacity coefficients, d(ln phi_i)/dT, for the given phase.

Temperature derivative of the natural logarithm of the fugacity coefficients, d(ln phi_i)/dT, for the given phase. Base implementation is a forward finite difference; EOS/activity packages override this with a closed-form expression. Distinct from DW_CalcdFugCoeffdT, which returns d(phi)/dT (not the logarithm).

Parameter	Type	Description
Vx	Double[]
T	Double
P	Double
st	State

C#VB.NET

public override double[] DW_CalcdLnFugCoeffdT(double[] Vx, double T, double P, State st)

Public Overrides Function DW_CalcdLnFugCoeffdT(Vx As Double(), T As Double, P As Double, st As State) As Double()

DW_CalcEnergyFlowMistura_ISOL(double, double)

Parameter	Type	Description
T	Double
P	Double

C#VB.NET

public override double DW_CalcEnergyFlowMistura_ISOL(double T, double P)

Public Overrides Function DW_CalcEnergyFlowMistura_ISOL(T As Double, P As Double) As Double

DW_CalcEnthalpy(Array, double, double, State): Calculates the enthalpy of a mixture.

Calculates the enthalpy of a mixture.

Parameter	Type	Description
Vx	Array	Vector of doubles containing the molar composition of the mixture.
T	Double	Temperature (K)
P	Double	Pressure (Pa)
st	State	State enum indicating the state of the mixture (liquid or vapor).

C#VB.NET

public override double DW_CalcEnthalpy(Array Vx, double T, double P, State st)

Public Overrides Function DW_CalcEnthalpy(Vx As Array, T As Double, P As Double, st As State) As Double

DW_CalcEnthalpyDeparture(Array, double, double, State): Calculates the enthalpy departure of a mixture.

Calculates the enthalpy departure of a mixture.

Parameter	Type	Description
Vx	Array	Vector of doubles containing the molar composition of the mixture.
T	Double	Temperature (K)
P	Double	Pressure (Pa)
st	State	State enum indicating the state of the mixture (liquid or vapor).

C#VB.NET

public override double DW_CalcEnthalpyDeparture(Array Vx, double T, double P, State st)

Public Overrides Function DW_CalcEnthalpyDeparture(Vx As Array, T As Double, P As Double, st As State) As Double

DW_CalcEntropy(Array, double, double, State): Calculates the entropy of a mixture.

Calculates the entropy of a mixture.

Parameter	Type	Description
Vx	Array	Vector of doubles containing the molar composition of the mixture.
T	Double	Temperature (K)
P	Double	Pressure (Pa)
st	State	State enum indicating the state of the mixture (liquid or vapor).

C#VB.NET

public override double DW_CalcEntropy(Array Vx, double T, double P, State st)

Public Overrides Function DW_CalcEntropy(Vx As Array, T As Double, P As Double, st As State) As Double

DW_CalcEntropyDeparture(Array, double, double, State): Calculates the entropy departure of a mixture.

Calculates the entropy departure of a mixture.

Parameter	Type	Description
Vx	Array	Vector of doubles containing the molar composition of the mixture.
T	Double	Temperature (K)
P	Double	Pressure (Pa)
st	State	State enum indicating the state of the mixture (liquid or vapor).

C#VB.NET

public override double DW_CalcEntropyDeparture(Array Vx, double T, double P, State st)

Public Overrides Function DW_CalcEntropyDeparture(Vx As Array, T As Double, P As Double, st As State) As Double

DW_CalcFugCoeff(Array, double, double, State): Calculates fugacity coefficients for the specified composition at the specified conditions.

Calculates fugacity coefficients for the specified composition at the specified conditions.

Parameter	Type	Description
Vx	Array	Vector of doubles containing the molar composition of the mixture.
T	Double	Temperature in K
P	Double	Pressure in Pa
st	State	Mixture state (Liquid or Vapor)

C#VB.NET

public override double[] DW_CalcFugCoeff(Array Vx, double T, double P, State st)

Public Overrides Function DW_CalcFugCoeff(Vx As Array, T As Double, P As Double, st As State) As Double()

DW_CalcFugCoeff(double[], double, double): Calculates fugacity coefficients for the specified composition at the specified conditions.

Calculates fugacity coefficients for the specified composition at the specified conditions.

Parameter	Type	Description
Vz	Double[]	Vector of doubles containing the molar composition of the mixture.
T	Double	Temperature in K
V	Double	Volume in m3/mol

C#VB.NET

public override double[] DW_CalcFugCoeff(double[] Vz, double T, double V)

Public Overrides Function DW_CalcFugCoeff(Vz As Double(), T As Double, V As Double) As Double()

DW_CalcK_ISOL(Phase, double, double)

Parameter	Type	Description
Phase1	Phase
T	Double
P	Double

C#VB.NET

public override double DW_CalcK_ISOL(Phase Phase1, double T, double P)

Public Overrides Function DW_CalcK_ISOL(Phase1 As Phase, T As Double, P As Double) As Double

DW_CalcMassaEspecifica_ISOL(Phase, double, double, double)

Parameter	Type	Description
Phase1	Phase
T	Double
P	Double
Pvp	Double

C#VB.NET

public override double DW_CalcMassaEspecifica_ISOL(Phase Phase1, double T, double P, double Pvp = 0)

Public Overrides Function DW_CalcMassaEspecifica_ISOL(Phase1 As Phase, T As Double, P As Double, Pvp As Double = 0) As Double

DW_CalcMM_ISOL(Phase, double, double)

Parameter	Type	Description
Phase1	Phase
T	Double
P	Double

C#VB.NET

public override double DW_CalcMM_ISOL(Phase Phase1, double T, double P)

Public Overrides Function DW_CalcMM_ISOL(Phase1 As Phase, T As Double, P As Double) As Double

DW_CalcOverallProps()

C#VB.NET

public override void DW_CalcOverallProps()

Public Overrides Sub DW_CalcOverallProps()

DW_CalcP(double[], double, double): Calculates system pressure for the specified temperature, volume and composition.

Calculates system pressure for the specified temperature, volume and composition.

Parameter	Type	Description
Vz	Double[]	Vector of doubles containing the molar composition of the mixture.
T	Double	Temperature in K
V	Double	Volume in m3/mol

C#VB.NET

public override double DW_CalcP(double[] Vz, double T, double V)

Public Overrides Function DW_CalcP(Vz As Double(), T As Double, V As Double) As Double

DW_CalcPhaseProps(Phase)

Parameter	Type	Description
Phase	Phase

C#VB.NET

public override void DW_CalcPhaseProps(Phase Phase)

Public Overrides Sub DW_CalcPhaseProps(Phase As Phase)

DW_CalcProp(string, Phase): Provides a wrapper function for CAPE-OPEN CalcProp/CalcSingleProp functions.

Provides a wrapper function for CAPE-OPEN CalcProp/CalcSingleProp functions.

Parameter	Type	Description
property	String	The property to be calculated.
phase	Phase	The phase where the property must be calculated for.

C#VB.NET

public override void DW_CalcProp(string property, Phase phase)

Public Overrides Sub DW_CalcProp([property] As String, phase As Phase)

DW_CalcPVAP_ISOL(double)

Parameter	Type	Description
T	Double

C#VB.NET

public override double DW_CalcPVAP_ISOL(double T)

Public Overrides Function DW_CalcPVAP_ISOL(T As Double) As Double

DW_CalcTensaoSuperficial_ISOL(Phase, double, double)

Parameter	Type	Description
Phase1	Phase
T	Double
P	Double

C#VB.NET

public override double DW_CalcTensaoSuperficial_ISOL(Phase Phase1, double T, double P)

Public Overrides Function DW_CalcTensaoSuperficial_ISOL(Phase1 As Phase, T As Double, P As Double) As Double

DW_CalcViscosidadeDinamica_ISOL(Phase, double, double)

Parameter	Type	Description
Phase1	Phase
T	Double
P	Double

C#VB.NET

public override double DW_CalcViscosidadeDinamica_ISOL(Phase Phase1, double T, double P)

Public Overrides Function DW_CalcViscosidadeDinamica_ISOL(Phase1 As Phase, T As Double, P As Double) As Double

EstimateMissingKij(ICompoundConstantProperties, ICompoundConstantProperties): kij for a pair that has no value in the interaction parameter table and none set by the user, or zero when the pair...

kij for a pair that has no value in the interaction parameter table and none set by the user, or zero when the pair keeps the default kij = 1. Hydrogen with any compound: HydrogenKijEstimate of the partner. Carbon dioxide or hydrogen sulfide with a hydrocarbon whose Tc is at least that of carbon dioxide: AcidGasKijEstimate. Two hydrocarbons (petroleum fractions included), or nitrogen or carbon monoxide with a hydrocarbon, whose critical temperatures differ by a factor of KijMinTcRatio or more: HydrocarbonKijEstimate. Closer pairs keep kij = 1.

Parameter	Type	Description
cp1	ICompoundConstantProperties
cp2	ICompoundConstantProperties

C#VB.NET

public static double EstimateMissingKij(ICompoundConstantProperties cp1, ICompoundConstantProperties cp2)

Public Shared Function EstimateMissingKij(cp1 As ICompoundConstantProperties, cp2 As ICompoundConstantProperties) As Double

GetEditingForm(): Returns the binary interaction parameter editor of this package.

Returns the binary interaction parameter editor of this package.

C#VB.NET

public override object GetEditingForm()

Public Overrides Function GetEditingForm() As Object

GetModel()

C#VB.NET

public override object GetModel()

Public Overrides Function GetModel() As Object

HydrocarbonKijEstimate(double, double, double, double): kij of a hydrocarbon, nitrogen or carbon monoxide (critical temperature Tc1 in K, critical volume Vc1 in m3/kmol)...

kij of a hydrocarbon, nitrogen or carbon monoxide (critical temperature Tc1 in K, critical volume Vc1 in m3/kmol) with a hydrocarbon of higher critical temperature Tc2 and critical volume Vc2: kij = 1 + 0.2802 ln(Tc2/Tc1) ln(Vc2/Vc1) - 0.0561 ln(Tc2/Tc1), or zero when Tc2/Tc1 is below KijMinTcRatio. Fitted to the 96 hydrocarbon, nitrogen and carbon monoxide pairs of the table (rms 0.011) and to kij regressed from 31 binary solubility data sets (rms 0.029): methane in n-C10 to n-C28, toluene, m-xylene, trans-decalin, naphthalene, 1-methylnaphthalene, phenanthrene and pyrene; ethane in n-C14, n-C18, n-C20 and toluene; nitrogen in n-C7 to n-C20 and benzene; carbon monoxide in n-C10 to n-C28, benzene and cyclohexane.

Parameter	Type	Description
Tc1	Double
Vc1	Double
Tc2	Double
Vc2	Double

C#VB.NET

public static double HydrocarbonKijEstimate(double Tc1, double Vc1, double Tc2, double Vc2)

Public Shared Function HydrocarbonKijEstimate(Tc1 As Double, Vc1 As Double, Tc2 As Double, Vc2 As Double) As Double

HydrogenEffectiveConstants(double, double): Effective critical temperature, critical pressure, critical volume and acentric factor of normal hydrogen at...

Effective critical temperature, critical pressure, critical volume and acentric factor of normal hydrogen at temperature T (K), from Gunn, Chueh and Prausnitz, AIChE J. 12 (1966) 937: Tc = 43.6/(1 + 21.8/(M T)) K, Pc = 20.5/(1 + 44.2/(M T)) atm, Vc = 51.5/(1 - 9.91/(M T)) cm3/mol, omega = 0. With these constants the hydrogen + n-hexane kij of the LKP table (Plöcker, Knapp and Prausnitz, 1978) reproduces the solubility data of Gao, Gasem and Robinson (344 to 411 K, 1 to 15 MPa) within 16 %. Returns Tc (K), Pc (Pa), Vc (m3/kmol), omega.

Parameter	Type	Description
T	Double
MW	Double

C#VB.NET

public static double[] HydrogenEffectiveConstants(double T, double MW)

Public Shared Function HydrogenEffectiveConstants(T As Double, MW As Double) As Double()

HydrogenKijEstimate(double, double, double): Hydrogen-compound kij for pairs missing from the interaction parameter table, from the partner's critical...

Hydrogen-compound kij for pairs missing from the interaction parameter table, from the partner's critical temperature Tc (K), acentric factor w and critical volume Vc (m3/kmol): kij = 0.2036 + 0.002246 Tc + 0.8364 w + 1.2111 Vc^(1/3). Fitted, with the effective hydrogen constants below, to the eleven hydrogen pairs of the table (N2, CO, CO2, CH4, C2H4, C2H6, C3H8, n-C4 to n-C7; within 2.4 %) and to kij regressed from hydrogen solubility data in n-dodecane (Gao, Gasem and Robinson, J. Chem. Eng. Data, 1999), benzene, toluene, cyclohexane and methylcyclohexane (Tsuji et al., Fluid Phase Equilib. 228-229 (2005) 499; Aslam et al., J. Chem. Eng. Data 61 (2016), doi 10.1021/acs.jced.5b00789).

Parameter	Type	Description
Tc	Double
w	Double
Vc	Double

C#VB.NET

public static double HydrogenKijEstimate(double Tc, double w, double Vc)

Public Shared Function HydrogenKijEstimate(Tc As Double, w As Double, Vc As Double) As Double

RET_KIJ(string, string)

Parameter	Type	Description
id1	String
id2	String

C#VB.NET

public double RET_KIJ(string id1, string id2)

Public Function RET_KIJ(id1 As String, id2 As String) As Double

RET_VKij()

C#VB.NET

public override double[,] RET_VKij()

Public Overrides Function RET_VKij() As Double(,)

SupportsComponent(ICompoundConstantProperties)

Parameter	Type	Description
comp	ICompoundConstantProperties

C#VB.NET

public override bool SupportsComponent(ICompoundConstantProperties comp)

Public Overrides Function SupportsComponent(comp As ICompoundConstantProperties) As Boolean

Fields

ClassId

C#VB.NET

public const string ClassId = "DF7C2420-1FBB-4b35-9D87-6ECF530FED7A"

Public Const ClassId As String = "DF7C2420-1FBB-4b35-9D87-6ECF530FED7A"

ip_changed

C#VB.NET

public bool ip_changed

Public ip_changed As Boolean

KijMinTcRatio: Smallest ratio of critical temperatures for which HydrocarbonKijEstimate applies.

Smallest ratio of critical temperatures for which HydrocarbonKijEstimate applies. Below it the table pairs scatter around kij = 1 by about 0.02 and the pair keeps kij = 1.

C#VB.NET

public const double KijMinTcRatio = 1.3

Public Const KijMinTcRatio As Double = 1.3

m_lk

C#VB.NET

public LeeKeslerPlocker m_lk

Public m_lk As LeeKeslerPlocker

m_pr

C#VB.NET

public PengRobinson m_pr

Public m_pr As PengRobinson

MAT_KIJ

C#VB.NET

public object[,] MAT_KIJ

Public MAT_KIJ As Object(,)