03_GROSS.js

//Version 2.0 of routines for the calculation of thermodynamic
// properties from the AGA 8 Part 1 GROSS equation of state.
// April, 2017

//Written by Eric W. Lemmon
//Applied Chemicals and Materials Division
//National Institute of Standards and Technology (NIST)
//Boulder, Colorado, USA
//Eric.Lemmon@nist.gov
//303-497-7939

//Other contributors:
//Volker Heinemann, RMG Messtechnik GmbH
//Jason Lu, Thermo Fisher Scientific
//Ian Bell, NIST

//The publication for the AGA 8 equation of state is available from AGA
//  and the Transmission Measurement Committee.

//Subroutines contained here for property calculations:
//***** Subroutine SetupGross must be called once before calling other routines. ******
//MolarMassGross(x, Mm)
//Sub PressureGross(T, D, xGrs, HCH, P, Z, ierr, herr)
//Sub DensityGross(T, P, xGrs, HCH, D, ierr, herr)
//Sub GrossHv(x, xGrs, HN, HCH)
//Sub GrossInputs(T, P, x, xGrs, Gr, HN, HCH, ierr, herr)
//Sub Bmix(T, xGrs, HCH, B, C, ierr, herr)
//Sub GrossMethod1(Th, Td, Pd, xGrs, Gr, Hv, Mm, HCH, HN, ierr, herr)
//Sub GrossMethod2(Th, Td, Pd, xGrs, Gr, Hv, Mm, HCH, HN, ierr, herr)
//Sub SetupGross()

//The compositions in the x() array use the following order and must be sent as mole fractions:
//    1 - Methane
//    2 - Nitrogen
//    3 - Carbon dioxide
//    4 - Ethane
//    5 - Propane
//    6 - Isobutane
//    7 - n-Butane
//    8 - Isopentane
//    9 - n-Pentane
//   10 - n-Hexane
//   11 - n-Heptane
//   12 - n-Octane
//   13 - n-Nonane
//   14 - n-Decane
//   15 - Hydrogen
//   16 - Oxygen
//   17 - Carbon monoxide
//   18 - Water
//   19 - Hydrogen sulfide
//   20 - Helium
//   21 - Argon
//
//For example, a mixture of 94% methane, 5% CO2, and 1% helium would be (in mole fractions):
//x(1)=0.94, x(3)=0.05, x(20)=0.01

//Variables containing the common parameters in the GROSS equations
//let MaxFlds = 21;
//let Epsilon = 0.000000000000001;  //1d-15
//let dPdDsave=0;
let GROSS={
    Pressure:400, //KPa
    Temperature:273.15, //Kelvin
    MolarMass:0, //g/mol
    Density:0.04464, //mol/l
    CompressibilityFactor:0,
    dPdD:0,
    xGrs:Array(4).fill(0),
    HN:0,   //kJ/mol
    HCH:0,   //kJ/mol
    Th:298.15,   //K
    Td:298.15,   //K
    Pd:0,   //kPa
    Gr:0,
    Hv:0,   //MJ/m^3
    ierr:0,
    herr:'',
    CalculateMolarMass(x){
        //Sub MolarMassGross(x, Mm)

        //Calculate molar mass of the mixture with the compositions contained in the x() input array
        //
        //Inputs:
        //   x() - Composition (mole fraction)
        //         Do not send mole percents or mass fractions in the x() array, otherwise the output will be incorrect.
        //         The sum of the compositions in the x() array must be equal to one.
        //         The order of the fluids in this array is given at the top of this code.
        //
        //Outputs:
        //    Mm - Molar mass (g/mol)
        Mm = 0;
        for (let i = 1; i <= NcGross;i++){
            Mm = Mm + x[i] * MMiGross[i];
        }
        GROSS.MolarMass = Mm;
    },
    CalculatePressure(T, D, xGrs,HCH){
        //Sub PressureGross(T, D, xGrs, HCH, P, Z, ierr, herr)
        //Calculate pressure as a function of temperature and density.  The derivative d(P)/d(D) is also calculated
        //for use in the iterative DensityGross subroutine (and is only returned as a common variable).
        //
        //Inputs:
        //     T - Temperature (K)
        //     D - Density (mol/l)
        //xGrs() - Compositions of the equivalent hydrocarbon, nitrogen, and CO2 (mole fractions)
        //   HCH - Molar ideal gross heating value of the equivalent hydrocarbon (kJ/mol) at 298.15 K
        //         ***Call subroutine GrossHv or GrossInputs first to obtain HCH.***
        //
        //Outputs:
        //     P - Pressure (kPa)
        let P=0;
        //     Z - Compressibility factor
        let Z=0;
        //  dPdDsave - d(P)/d(D) [kPa/(mol/l)] (at constant temperature)
        //           - This variable is cached in the common variables for use in the iterative density solver, but not returned as an argument.
        //  ierr - Error number (0 indicates no error)
        let ierr;
        //  herr - Error message if ierr is not equal to zero
        let herr;
        let B=0;
        let C=0;
        Z = 1;
        P = D * RGross * T;
        [B, C, ierr, herr]=GROSS.CalculateBmix(T, xGrs, HCH);
        if (ierr > 0){return};
        Z = 1 + B * D + C * Math.pow(D, 2);
        P = D * RGross * T * Z;
        dPdDsave = RGross * T * (1 + 2 * B * D + 3 * C * Math.pow(D, 2));
        if(P < 0){
            ierr = -1;
            herr = "Pressure is negative in the GROSS method.";
        }
        GROSS.Pressure = P;
        GROSS.CompressibilityFactor = Z;
        GROSS.ierr = ierr;
        GROSS.herr = herr;
    },
    CalculateDensity(T,P,xGrs,HCH){
        //Sub DensityGross(T, P, xGrs, HCH, D, ierr, herr)
        //Calculate density as a function of temperature and pressure.  This is an iterative routine that calls PressureGross
        //to find the correct state point.  Generally only 6 iterations at most are required.
        //If the iteration fails to converge, the ideal gas density and an error message are returned.
        //Inputs:
        //     T - Temperature (K)
        //     P - Pressure (kPa)
        //xGrs() - Compositions of the equivalent hydrocarbon, nitrogen, and CO2 (mole fractions)
        //   HCH - Molar ideal gross heating value of the equivalent hydrocarbon (kJ/mol) at 298.15 K
        //         ***Call subroutine GrossHv or GrossInputs first to obtain HCH.***
        //Outputs:
        //     D - Density (mol/l)
        let D;
        //  ierr - Error number (0 indicates no error)
        let ierr;
        //  herr - Error message if ierr is not equal to zero
        let herr;
        let it;
        let plog;
        let vlog;
        let P2;
        let Z;
        let dpdlv;
        let vdiff;
        let tolr;
        ierr = 0;
        herr = '';
        if(P < Epsilon){D = 0; return}
        tolr = 0.0000001;
        D = P / RGross / T;       //Ideal gas estimate
        plog = Math.log(P);
        vlog = -Math.log(D);
        for (it = 1; it <= 20; it++){
            if(vlog < -7 || vlog > 100){GoToDError()}
            D = Math.exp(-vlog);
            GROSS.CalculatePressure(T, D, xGrs, HCH);
            P2 = GROSS.Pressure;
            Z = GROSS.CompressibilityFactor;
            ierr = GROSS.ierr;
            herr = GROSS.herr;
            if (ierr > 0){GROSS.Density = D;GROSS.ierr = ierr;GROSS.herr = herr;return}
            if (dPdDsave < Epsilon || P2 < Epsilon){
                vlog = vlog + 0.1;
            }else{
            //Find the next density with a first order Newton's type iterative scheme, with
            //log(P) as the known variable and log(v) as the unknown property.
            //See AGA 8 publication for further information.
                dpdlv = -D * dPdDsave;     //d(p)/d[log(v)]
                vdiff = (Math.log(P2) - plog) * P2 / dpdlv;
                vlog = vlog - vdiff;
                if(Math.abs(vdiff) < tolr){
                    if(P2 < 0){GoToDError()};
                    D = Math.exp(-vlog);
                    GROSS.dPdD = dPdDsave;
                    GROSS.Density = D;
                    GROSS.ierr = ierr;
                    GROSS.herr = herr;
                    return;         //Iteration converged
                }
            }
        }
        function GoToDError(){
            ierr = 10;
            herr = 'Calculation failed to converge in the GROSS method, ideal gas density returned.';
            D = P / RGross / T;
        }
    },
    CalculateHv(x){
        //Sub GrossHv(x, xGrs, HN, HCH)
        //Calculate ideal heating values based on composition.  The mole fractions in the mixture are required in this routine, not
        //  just xCH, xN2, and xCO2.
        //
        //Inputs:
        //   x() - Molar compositions of all components in the mixture.  The order in this array is given at the top of this code.
        //
        //Outputs:
        //xGrs() - Compositions of the equivalent hydrocarbon, nitrogen, and CO2 (mole fractions)
        let xGrs=[];
        //    HN - Molar ideal gross heating value of the mixture (kJ/mol) at 298.15 K
        let HN;
        //   HCH - Molar ideal gross heating value of the equivalent hydrocarbon (kJ/mol) at 298.15 K
        let HCH;
        xGrs[1] = 1 - x[2] - x[3];
        xGrs[2] = x[2];
        xGrs[3] = x[3];
        HN = 0;
        for(let i = 1; i <= NcGross; i++){
            HN = HN + x[i] * xHN[i];
        }
        HCH = 0;
        if (xGrs[1] > 0){HCH = HN / xGrs[1]}
        GROSS.xGrs = xGrs;
        GROSS.HN = HN;
        GROSS.HCH = HCH;
    },
    CalculateInputs(T,P,x){
        //Sub GrossInputs(T, P, x, xGrs, Gr, HN, HCH, ierr, herr)

        //Calculate relative density and heating values based on composition.  This routine should only be used to get these
        //  two values for use as inputs to Method 1 or Method 2, and not for the relative density for any T and P.
        //  All of the mole fractions in the mixture are required in this routine, not just xCH, xN2, and xCO2.
        //
        //Inputs:
        //     T - Temperature (K), generally a reference temperature for relative density
        //     P - Pressure (kPa), generally a reference pressure for relative density
        //   x() - Molar compositions of all components in the mixture.  The order in this array is given at the top of this code.
        //
        //Outputs:
        //xGrs() - Compositions of the equivalent hydrocarbon, nitrogen, and CO2 (mole fractions)
        let xGrs=[];
        //    Gr - Relative density at T and P
        let Gr;
        //    HN - Molar ideal gross heating value of the mixture (kJ/mol) at 298.15 K
        let HN;
        //   HCH - Molar ideal gross heating value of the equivalent hydrocarbon (kJ/mol) at 298.15 K
        let HCH;
        //  ierr - Error number (0 indicates no error)
        let ierr;
        //  herr - Error message if ierr is not equal to zero
        let herr;
        let Bref;
        let Zref;
        let Mref;
        let Z;
        let D;
        let Mm;
        ierr = 0;
        herr = '';
        GROSS.CalculateHv(x);
        xGrs=GROSS.xGrs;
        HN=GROSS.HN;
        HCH=GROSS.HCH;
        if(HCH==0){return};
        Bref = -0.12527 + 0.000591 * T - 0.000000662 * Math.pow(T , 2);    //2nd virial coefficient of the reference fluid at T
        Zref = 1 + Bref * P / RGross / T;                                  //Z of the reference fluid at T and P
        Mref = 28.9625;
        GROSS.CalculateMolarMass(x);
        Mm = GROSS.MolarMass;
        GROSS.CalculateDensity(T, P, xGrs, HCH);           //Density of the input fluid at T and D
        D = GROSS.Density;
        ierr = GROSS.ierr;
        herr = GROSS.herr;
        Z = P / T / D / RGross;                                            //Z of the input fluid at T and D
        Gr = Mm * Zref / Mref / Z;
        GROSS.xGrs = xGrs;
        GROSS.Gr = Gr;
        GROSS.HN = HN;
        GROSS.HCH = HCH;
        GROSS.ierr = ierr;
        GROSS.herr = herr;
    },
    CalculateBmix(T,xGrs,HCH){
        //Sub Bmix(T, xGrs, HCH, B, C, ierr, herr)
        //Calculate 2nd and 3rd virial coefficients for the mixture at T.
        //
        //Inputs:
        //     T - Temperature (K)
        //xGrs() - Compositions of the equivalent hydrocarbon, nitrogen, and CO2 (mole fractions)
        //   HCH - Molar ideal gross heating value of the equivalent hydrocarbon (kJ/mol) at 298.15 K
        //
        //Outputs:
        //     B - Second virial coefficient (dm^3/mol)
        let B=0;
        //     C - Third virial coefficient (dm^6/mol^2)
        let C=0;
        //  ierr - Error number (0 indicates no error)
        let ierr=0;
        //  herr - Error message if ierr is not equal to zero
        let herr='';
        let i;let j;let k;
        let bCH=Array(3+1).fill(0);
        let cCH=Array(3+1).fill(0);
        BB=zeros([3, 3]);
        CC=zeros([3, 3, 3]);
        let onethrd;
    //Temperature dependent Bi and Ci values for obtaining B(CH-CH) and C(CH-CH-CH)
        for (i = 0; i <= 2; i++){
            bCH[i] = bCHx[0][i] + bCHx[1][i] * T + bCHx[2][i] * Math.pow(T , 2);
            cCH[i] = cCHx[0][i] + cCHx[1][i] * T + cCHx[2][i] * Math.pow(T , 2);
        }
    //Bij and Cijk values for nitrogen and CO2
        for (i = 2; i <= 3; i++){
            for (j = i ; j<= 3; j++){
                BB[i][j] = b0[i][j] + b1[i][j] * T + b2[i][j] * Math.pow(T , 2);
                for(k = j; k <= 3; k++){
                    CC[i][j][k] = c0[i][j][k] + c1[i][j][k] * T + c2[i][j][k] * Math.pow(T , 2);
                }
            }
        }
    //Bij values for use in calculating Bmix
        BB[1][1] = bCH[0] + bCH[1] * HCH + bCH[2] * Math.pow(HCH , 2);                                               //B(CH-CH) for the equivalent hydrocarbon
        BB[1][2] = (0.72 + 0.00001875 * Math.pow((320 - T) , 2)) * (BB[1][1] + BB[2][2]) / 2;                        //B(CH-N2)
        if(BB[1][1] * BB[3][3] < 0){ierr = 4; herr = "Invalid input in Bmix routine"; return[B, C, ierr, herr]};
        BB[1][3] = -0.865 * Math.sqrt(BB[1][1] * BB[3][3]);                                                          //B(CH-CO2)
    //Cijk values for use in calculating Cmix
        onethrd = 1 / 3;
        CC[1][1][1] = cCH[0] + cCH[1] * HCH + cCH[2] * Math.pow(HCH , 2);                                            //C(CH-CH-CH) for the equivalent hydrocarbon
        if(CC[1][1][1] < 0 || CC[3][3][3] < 0) {ierr = 5; herr = "Invalid input in Bmix routine"; return[B, C, ierr, herr]}
        CC[1][1][2] = (0.92 + 0.0013 * (T - 270)) * Math.pow((Math.pow(CC[1][1][1] , 2) * CC[2][2][2]), onethrd);    //C(CH-CH-N2)
        CC[1][2][2] = (0.92 + 0.0013 * (T - 270)) * Math.pow((Math.pow(CC[2][2][2] , 2) * CC[1][1][1]), onethrd);    //C(CH-N2-N2)
        CC[1][1][3] = 0.92 * (Math.pow(CC[1][1][1] , 2) * Math.pow(CC[3][3][3]) , onethrd);                          //C(CH-CH-CO2)
        CC[1][3][3] = 0.92 * (Math.pow(CC[3][3][3] , 2) * Math.pow(CC[1][1][1]) , onethrd);                          //C(CH-CO2-CO2)
        CC[1][2][3] = 1.1 * (CC[1][1][1] * CC[2][2][2] * Math.pow(CC[3][3][3]) , onethrd);                           //C(CH-N2-CO2)
    //Calculate Bmix and Cmix
        for (i = 1 ; i<= 3;i++){
            for (j = i ; j <= 3; j++){
                if (i == j){
                    B = B + BB[i][i] * Math.pow(xGrs[i], 2);
                }else{
                    B = B + 2 * BB[i][j] * xGrs[i] * xGrs[j];
                }
                for (k = j ; k <= 3; k ++){
                    if (i == j && j == k){
                        C = C + CC[i][i][i] * Math.pow(xGrs[i], 3);
                    }else if(i != j && j != k && i != k){
                        C = C + 6 * CC[i][j][k] * xGrs[i] * xGrs[j] * xGrs[k];
                    }else{
                        C = C + 3 * CC[i][j][k] * xGrs[i] * xGrs[j] * xGrs[k];
                    }
                }
            }
        }
        return [B, C, ierr, herr];
    },
    Method1(Th,Td,Pd,xGrs,Gr,Hv){
        //Sub GrossMethod1(Th, Td, Pd, xGrs, Gr, Hv, Mm, HCH, HN, ierr, herr)

        //Initialize variables required in the GROSS equation with Method 1 of the AGA 8 Part 1 publication.
        //Method 1 requires inputs of volumetric gross heating value, relative density, and mole fraction of CO2.
        //
        //Inputs:
        //    Th - Reference temperature for heating value (K)
        //    Td - Reference temperature for density (K)
        //    Pd - Reference pressure for density (kPa)
        //xGrs() - Array of size 3 with the molar composition of CO2 in the 3rd position.  xCH and xN2 are returned in this array.
        //    Gr - Relative density at Td and Pd
        //    Hv - Volumetric ideal gross heating value (MJ/m^3) at Th
        //
        //Outputs:
        //xGrs() - Compositions of the equivalent hydrocarbon, nitrogen, and CO2 (mole fractions)
        //    Mm - Molar mass (g/mol)
        //   HCH - Molar ideal gross heating value of the equivalent hydrocarbon (kJ/mol) at 298.15 K
        //    HN - Molar ideal gross heating value of the mixture (kJ/mol) at 298.15 K
        //  ierr - Error number (0 indicates no error)
        //  herr - Error message if ierr is not equal to zero
        let xCH;let xN2;let xCO2;let Zd;let Zold;
        let G1; let G2; let Bref; let Zref; let B; let C;
        let HCH;let HN;
        ierr = 0;
        herr = '';
        if (Gr < Epsilon) {ierr = 1; herr = "Invalid input for relative density"; return}
        if (Hv < Epsilon) {ierr = 2; herr = "Invalid input for heating value"; return}
        xCO2 = xGrs[3];
        Zd = 1;
        G1 = -2.709328;
        G2 = 0.021062199;
        Bref = -0.12527 + 0.000591 * Td - 0.000000662 * Math.pow(Td , 2);           //dm^3/mol
        Zref = (1 + Pd / RGross / Td * Bref);
        for (let i = 1; i <= 20; i++){
            Zold = Zd;
            HN = Zd * RGross * Td / Pd * Hv * (1 + 0.0001027 * (Th - 298.15));      //kJ/mol at 25 C
            Mm = Gr * Zd * 28.9625 / Zref;                                          //g/mol
            xCH = (Mm + (xCO2 - 1) * mN2 - xCO2 * mCO2 - G2 * HN) / (G1 - mN2);
            xN2 = 1 - xCH - xCO2;
            if(xN2 < 0){ierr = 3; herr = 'Negative nitrogen value in GROSS method 1 setup';GROSS.ierr = ierr;GROSS.herr = herr;return};
            HCH = HN / xCH;
            xGrs[1] = xCH;
            xGrs[2] = xN2;
            [B, C, ierr, herr]=GROSS.CalculateBmix(Td, xGrs, HCH);
            if(ierr > 0) {GROSS.xGrs = xGrs;GROSS.MolarMass = Mm;GROSS.HN = HN;GROSS.ierr = ierr;GROSS.herr = herr;return}
            Zd = 1 + B * Pd / RGross / Td;
            if(Math.abs(Zold - Zd) < 0.0000001){break}
        }
        GROSS.xGrs = xGrs;
        GROSS.MolarMass = Mm;
        GROSS.HN = HN;
        GROSS.ierr = ierr;
        GROSS.herr = herr;
    },
    Method2(Th,Td,Pd,xGrs,Gr){
        //Sub GrossMethod2(Th, Td, Pd, xGrs, Gr, Hv, Mm, HCH, HN, ierr, herr)
        //Initialize variables required in the GROSS equation with Method 2 of the AGA 8 Part 1 publication.
        //Method 2 requires inputs of relative density and mole fractions of nitrogen and CO2.
        //Inputs:
        //    Th - Reference temperature for heating value (K)
        //    Td - Reference temperature for density (K)
        //    Pd - Reference pressure for density (kPa)
        //xGrs() - Array of size 3 with the molar composition of N2 in the 2nd position and CO2 in the 3rd position.  xCH is returned in this array.
        //    Gr - Relative density at Td and Pd
        //
        //Outputs:
        //xGrs() - Compositions of the equivalent hydrocarbon, nitrogen, and CO2 (mole fractions)
        //    Mm - Molar mass (g/mol)
        //    Hv - Volumetric ideal gross heating value (MJ/m^3) at Th
        //   HCH - Molar ideal gross heating value of the equivalent hydrocarbon (kJ/mol) at 298.15 K
        //    HN - Molar ideal gross heating value of the mixture (kJ/mol) at 298.15 K
        //  ierr - Error number (0 indicates no error)
        //  herr - Error message if ierr is not equal to zero
        let xCH;let Z; let Zold; let Bref ; let Zref; let MrCH;
        let G1;let G2;let B;let C;let xN2;let xCO2;
        let HCH; let HN;
        let ierr = 0;
        let herr = "";
        if(Gr < Epsilon){ierr = 1; herr = "Invalid input for relative density"; return};
        xN2 = xGrs[2];
        xCO2 = xGrs[3];
        xCH = 1 - xN2 - xCO2;
        xGrs[1] = xCH;
        Z = 1;
        G1 = -2.709328;
        G2 = 0.021062199;
        Bref = -0.12527 + 0.000591 * Td - 0.000000662 * Math.pow(Td, 2);
        Zref = (1 + Pd / RGross / Td * Bref);
        for (let i = 1; i <= 20; i++){
            Zold = Z;
            Mm = Gr * Z * 28.9625 / Zref;
            MrCH = (Mm - xN2 * mN2 - xCO2 * mCO2) / xCH;
            HCH = (MrCH - G1) / G2;
            [B, C, ierr, herr] = GROSS.CalculateBmix(Td, xGrs, HCH);
            if (ierr > 0) {return}
            Z = 1 + B * Pd / RGross / Td;
            if (Math.abs(Zold - Z) < 0.0000001){break}
        }
        HN = HCH * xCH;
        Hv = HN / Z / RGross / Td * Pd / (1 + 0.0001027 * (Th - 298.15));
        GROSS.xGrs = xGrs;
        GROSS.MolarMass = Mm;
        GROSS.Hv = Hv;
        GROSS.HCH = HCH;
        GROSS.HN = HN;
        GROSS.ierr = ierr;
        GROSS.herr = herr;
    },
    //The following routine must be called once before any other routine.
    Setup(){
        //Initialize all the constants and parameters in the GROSS model.
        RGross = 8.31451;
        //Molar masses [g/mol].  These are the same as those in the DETAIL method.
        MMiGross[1] = 16.043;    //Methane
        MMiGross[2] = 28.0135;   //Nitrogen
        MMiGross[3] = 44.01;     //Carbon dioxide
        MMiGross[4] = 30.07;     //Ethane
        MMiGross[5] = 44.097;    //Propane
        MMiGross[6] = 58.123;    //Isobutane
        MMiGross[7] = 58.123;    //n-Butane
        MMiGross[8] = 72.15;     //Isopentane
        MMiGross[9] = 72.15;     //n-Pentane
        MMiGross[10] = 86.177;   //Hexane
        MMiGross[11] = 100.204;  //Heptane
        MMiGross[12] = 114.231;  //Octane
        MMiGross[13] = 128.258;  //Nonane
        MMiGross[14] = 142.285;  //Decane
        MMiGross[15] = 2.0159;   //Hydrogen
        MMiGross[16] = 31.9988;  //Oxygen
        MMiGross[17] = 28.01;    //Carbon monoxide
        MMiGross[18] = 18.0153;  //Water
        MMiGross[19] = 34.082;   //Hydrogen sulfide
        MMiGross[20] = 4.0026;   //Helium
        MMiGross[21] = 39.948;   //Argon
        //Initialize constants
        b0[2][2] = -0.1446;           b1[2][2] = 0.00074091;         b2[2][2] = -0.00000091195;
        b0[2][3] = -0.339693;         b1[2][3] = 0.00161176;         b2[2][3] = -0.00000204429;
        b0[3][3] = -0.86834;          b1[3][3] = 0.0040376;          b2[3][3] = -0.0000051657;
        c0[2][2][2] = 0.0078498;      c1[2][2][2] = -0.000039895;    c2[2][2][2] = 0.000000061187;
        c0[2][2][3] = 0.00552066;     c1[2][2][3] = -0.0000168609;   c2[2][2][3] = 0.0000000157169;
        c0[2][3][3] = 0.00358783;     c1[2][3][3] = 0.00000806674;   c2[2][3][3] = -0.0000000325798;
        c0[3][3][3] = 0.0020513;      c1[3][3][3] = 0.000034888;     c2[3][3][3] = -0.000000083703;
        bCHx[0][0] = -0.425468;       bCHx[1][0] = 0.002865;         bCHx[2][0] = -0.00000462073;
        bCHx[0][1] = 0.000877118;     bCHx[1][1] = -0.00000556281;   bCHx[2][1] = 0.0000000088151;
        bCHx[0][2] = -0.000000824747; bCHx[1][2] = 0.00000000431436; bCHx[2][2] = -6.08319E-12;
        cCHx[0][0] = -0.302488;       cCHx[1][0] = 0.00195861;       cCHx[2][0] = -0.00000316302;
        cCHx[0][1] = 0.000646422;     cCHx[1][1] = -0.00000422876;   cCHx[2][1] = 0.00000000688157;
        cCHx[0][2] = -0.000000332805; cCHx[1][2] = 0.0000000022316;  cCHx[2][2] = -3.67713E-12;
        //Heating values from ISO 6976 at 25 C (kJ/mol)
        //xHN(1) = 890.58    'Methane
        //xHN(2) = 0         'Nitrogen
        //xHN(3) = 0         'Carbon dioxide
        //xHN(4) = 1560.69   'Ethane
        //xHN(5) = 2219.17   'Propane
        //xHN(6) = 2868.2    'Isobutane
        //xHN(7) = 2877.4    'n-Butane
        //xHN(8) = 3528.83   'Isopentane
        //xHN(9) = 3535.77   'n-Pentane
        //xHN(10) = 4194.95  'Hexane
        //xHN(11) = 4853.43  'Heptane
        //xHN(12) = 5511.8   'Octane
        //xHN(13) = 6171.15  'Nonane
        //xHN(14) = 6829.77  'Decane
        //xHN(15) = 285.83   'Hydrogen
        //xHN(16) = 0        'Oxygen
        //xHN(17) = 282.98   'Carbon monoxide
        //xHN(18) = 44.013   'Water
        //xHN(19) = 562.01   'Hydrogen sulfide
        //xHN(20) = 0        'Helium
        //xHN(21) = 0        'Argon
        //Heating values from AGA-5, 2009 at 25 C (kJ/mol)
        xHN[1] = 890.63;     //Methane
        xHN[2] = 0;          //Nitrogen
        xHN[3] = 0;          //Carbon dioxide
        xHN[4] = 1560.69;    //Ethane
        xHN[5] = 2219.17;    //Propane
        xHN[6] = 2868.2;     //Isobutane
        xHN[7] = 2877.4;     //n-Butane
        xHN[8] = 3528.83;    //Isopentane
        xHN[9] = 3535.77;    //n-Pentane
        xHN[10] = 4194.95;   //Hexane
        xHN[11] = 4853.43;   //Heptane
        xHN[12] = 5511.8;    //Octane
        xHN[13] = 6171.15;   //Nonane
        xHN[14] = 6829.77;   //Decane
        xHN[15] = 285.83;    //Hydrogen
        xHN[16] = 0;         //Oxygen
        xHN[17] = 282.98;    //Carbon monoxide
        xHN[18] = 44.016;    //Water
        xHN[19] = 562.01;    //Hydrogen sulfide
        xHN[20] = 0;         //Helium
        xHN[21] = 0;         //Argon
        mN2 = MMiGross[2];
        mCO2 = MMiGross[3];
    }
}