Chemical Equilibrium Problem

    {  Chem.mpl  }

    {  GAMS Model Library, http://www.gams.com/modlib/libhtml/chem.htm  }

    {  Chemical Equilibrium Problem, Non Linear, Size: 4 x 11  }


TITLE
    Chem;

Option
    Modeltype=nonlinear
    Parsertype=extended

INDEX
    c := (H, H2, H2O, N, N2, NH, NO, O, O2, OH);
    i := (aH, aN,aO);

DATA

    A[i,c] := (1,2,2,0,0,1,0,0,0,1,
               0,0,0,1,2,1,1,0,0,0,
               0,0,1,0,0,0,1,1,2,1);
    Mix[i] := (2,1,1);
    Gibbs[c] := (-10.021, -21.096, -37.986, -9.846, -28.653, -18.918, -28.032, -14.640, -30.594, -26.11);
    Gplus[c] := Gibbs + log(750 * 0.07031);


VARIABLES
    X[c];
    Xb;


MODEL

    MIN Energy = SUM(c: X * (Gplus + log(X / Xb)));

SUBJECT TO

    Cdef[i]: SUM(c: A * X) = Mix;

    Xdef:    Xb = SUM(c: X);

BOUNDS
    X  >= 0.001;
    Xb >= 0.01;