Methane formation and water-gas shift reactions over potassium carbonate loaded on coal char at elevated pressure in H2-CO-H2O system.

Abstract

The rate of methane formation over potassium carbonate catalyst loaded on coal char was measured at elevated pressure in the range 1.5-2.0 MPa in the H2-CO-H2O system. The rate of simultaneous progress of the water-gas shift reaction was also measured. The effect of gaseous components on these reactions was investigated to obtain the respective rate equations. The existence of H2O in the reactant gas decreased the rate of methane formation through CO hydrogenation and enhanced that through carbon hydrogenation. In the H2-CO-H2O system, the rate of carbon hydrogenation is comparable to that of the CO hydrogenation as reaction temperature becomes high and suitable for steam gasification. The fixed-bed gasification was carried out at 2 MPa and 1023 K, and the exit gas compositions were simulated on the basis of these kinetic data. The calculated results agreed fairly well with the experimental ones.