Equilibrium Analysis Ofch(4),Co,Co2,H2o,H-2,Cmixtures Inc-H-Oatom Space Using Gibbs Free Energy Global Minimization

Gibbs free energy minimization is employed to carry out thermodynamic equilibrium analysis studies of mixtures containing methane, carbon monoxide, carbon dioxide, water, and hydrogen ideal gases, and possibly solid carbon. The employed global minimization approach represents a general, unifying, conceptual framework that allows reaction and phase equilibrium analysis to be simultaneously carried out in the atom-mol fraction space(a(H), a(O)), thus capturing in a comprehensive manner the equilibrium behavior of a number of industrially important processes, such as methane reforming (steam, dry, energetically enhanced), and methanation. Two theorems are presented, establishing necessary and sufficient (necessary) feasibility and regularity (optimality) conditions for the aforementioned minimization problem. The equilibrium results obtained through application of these theorems are guaranteed to be globally optimal. They quantify in(a(H), a(O))space, the feasible region, the carbon formation region, and all species mole over total atom-mol normalized ratios, for a range of temperatures and pressures.