Thermodynamic modeling of the water-gas shift reaction in supercritical water for hydrogen production

In this study, a computational model is developed for the estimation of the equilibrium composition of WGSR (water gas shift reaction) based on the stoichiometric and nonstoichiometric thermodynamic approaches. The model employs the Peng–Robinson equation of state (PR-EoS) formulation and the Gibbs free energy minimization. A Matlab computer program is developed for the numerical solution of a highly nonlinear equation of systems satisfying thermodynamic constraints. Molar fractions of each species are determined for different physical conditions using the proposed computational model and the computer code. Comparisons of model predictions with previous results show that molar fractions can be computed accurately using the present computational algorithm. On the basis of the numerical tests, a novel empirical expression is proposed to determine the hydrogen yield for energy considerations.