Catalytic supercritical water gasification mechanism of coal

Abstract

Catalytic supercritical water gasification (SCWG) for H2 production is a hopeful way of coal conversion to replace the traditional coal utilization mode. At present, the detailed catalytic mechanism in the process remains unknown. Herein, a comprehensive catalytic SCWG mechanism of coal is proposed by establishing a novel catalytic kinetic model. It shows that catalysts (K2CO3) break up the coal matrix by a cyclic redox reaction to produce plenty of mesopores, accelerating steam reforming of fixed carbon and coal pyrolysis. Water-gas shift reaction is facilitated by K2CO3 via formation of formate, which then promotes steam reforming of CH4 at high temperature (≥700 °C) due to the decreasing CO. The proposed mechanism provides important insights in catalytic SCWG process of coal.