Mechanism study on quantification of sulfurization effect on methane decomposition with CuO oxygen carrier

Abstract

The sulfur-containing impurity in natural gas, coal, and organic solid wastes generally exerts significant impacts on the dynamic evolution of sulfur oxides emission in atmosphere, and results in the degraded reaction performance of chemical looping process. Methane is the main component of natural gas and a typical pyrolysis and gasification product of solid waste, so it is of great significance to quantify the toxicological effects on the conversion of methane. this work realizes the accurate prediction of methane heterogeneous conversion in a multiscale kinetic model, and innovatively establishes a framework for quantifying the toxicological effect on the oxygen carrier particles. The kinetic parameters of methane oxidation over fresh and sulfurized oxygen carriers are calculated using density functional theory, and the sensitivity analysis of rate constant is conducted to forecast the priority of different reactions. Results indicate that the effect of residual sulfur in oxygen carrier is complex and not monotonically inhibited, and the sulfurization significantly limits the methane oxidation reactivity by reducing the reaction rate of the rate-limited dissociation step under the high-temperature condition. The multi-scale kinetic simulations reveal that the maximum instantaneous rate of sulfurized oxygen carrier is decreased by 7.45 %, which is deemed as the attenuation factor of 0.9255 derived from the toxicological effects of sulfurization.