Equilibrium Composition of Products Formed by Non-catalytic Conversion of Hydrocarbons

Abstract

The kinetic patterns of the attainment of the equilibrium product composition in non-catalytic processes of partial oxidation and of steam and carbon dioxide reforming of hydrocarbons in the temperature range 1400–1800 K, characteristic of these processes, were analyzed. The need for such analysis is caused by the rapidly increasing consumption of natural gas as a chemical feedstock and by growing attention to environmental problems, in particular, to a decrease in СО2 emissions or to partial CO2 utilization. The forward and reverse water gas shift reactions (WGSRs) play an important role in approach to the equilibrium product composition in these processes. Analysis has shown that the elementary reactions characteristic of forward and reverse WGSRs start to play a significant role long before the equilibrium in the system is attained. Already in the intermediate steps of the process, the distribution of the major reaction products, Н2, СО, Н2О, and СО2, almost corresponds to the equilibrium value of Kt = ([H2][CO2])/([CO][H2O]), close to the WGSR equilibrium constant Keq, and further conversion of the products occurs at Kt values close to Keq.