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Chemical Reactions

Model a chemical process of two species, FLB and ZHU, which are continuously mixed with carbon dioxide.

    
The inflow of carbon dioxide per unit volume is denoted by:
Wolfram Language code: Fin = klA (pCO2 / H - CO2[t]);
Specify the rate equations for each of the reactions:
Wolfram Language code: r1 = k1 FLB[t]^2CO2[t]^0.5; r2 = k2 FLBT[t] ZHU[t]; r3 = (k2 / KK)FLB[t] ZLA[t]; r4 = k3 FLB[t]ZHU[t]^2 CO2[t]; r5 = k4 FLBZHU[t]CO2[t]^0.5;
The governing equations for the rate of change of concentrations of each chemical species depend on the rate equations and the reactions:
Wolfram Language code: eqns = {FLB'[t] == -2 r1 + r2 - r3 - r4, CO2'[t] == -0.5 r1 - r4 - 0.5r5 + Fin, FLBT'[t] == r1 - r2 + r3, ZHU'[t] == -r2 + r3 - 2 r4, ZLA'[t] == r2 - r3 + r5};
The last reaction represents an equilibrium reaction:
Wolfram Language code: eqEqn = Ks FLB[t] ZHU[t] == FLBZHU[t];
Define the reaction parameters for each of the reactions:
Wolfram Language code: params = {k1 -> 18.7, k2 -> 0.58, k3 -> 0.09, k4 -> 0.42, KK -> 34.4, klA -> 3.3, Ks -> 115.83, pCO2 -> 0.9, H -> 737};
Specify the initial concentrations of each species:
Wolfram Language code: ics = {FLB[0] == 0.444, CO2[0] == 0.00123, FLBT[0] == 0, ZHU[0] == 0.007, ZLA[0] == 0};
Solve and visualize the change in concentration of the species over time:
Wolfram Language code: sol = NDSolve[{eqns, eqEqn, ics} /. params, {FLB, ZHU, CO2, ZLA}, {t, 0, 200}];
Wolfram Language code: plots = Plot[Evaluate[#[t] /. sol], {t, 0, 200}, PlotRange -> All, PlotLabel -> #[t]]& /@ {FLB, ZHU, CO2, ZLA};
Wolfram Language code: GraphicsGrid[Partition[plots, 2]]