Optimization of Ethanol Autothermal Reforming Process with Chemical Equilibrium Calculations

The dependence of carbon formation, hydrogen yield and efficiency of the ethanol autothermal reforming process on critical process factors is studied in the work by using chemical equilibrium calculations with a process simulation model made in the ChemCAD environment. The studied process factors are carbon-to-steam ratio S/C, air-to-fuel ratio λ and temperature in the reactor T_ATR. Since the goal of the reforming process is to achieve possibly higher values of H₂ concentration in the reforming gas, by operating reformer at the maximum efficiency at the same time, the optimization of the reforming process was done by using objective functions which include hydrogen yield and the amount of heat supplied to the process. As a result it was found that the maximum process efficiency, which is defined as the ratio of obtained hydrogen energy to the energy supplied to the process in the studied range of process factors is 0,61, and this value can be achieved at λ value of 0,1, S/C values of 2,5-3 and temperatures in the reactor T_ATR 680 - 695°C. Hydrogen yield under these conditions is 4,41-4,55 mol/molC₂H₅OH.