Exploration of Co-Gasification Mechanism of Sewage Sludge and Bituminous Coal Based on Reaxff-Md Methods

Abstract

Co-gasification of sludge and coal represents a promising strategy for sludge management. This study employed the ReaxFF-MD simulation method to explore the underlying mechanisms of co-gasification. Specifically, monomeric β-D-glucose, glyceryl triacetate, leucine were selected as molecular models for sludge, and bituminous coal was used as a representative model for coal to investigate their behaviors during the co-gasification process. The results demonstrated that these molecules sequentially decomposed into smaller fragments. The OH radicals generated throughout the decomposition process markedly expedite the fragmentation of both ring and chain structures, yielding hydrocarbons in the C5 to C15 range. Concurrently, H radicals reacted with oxygenated functional groups to produce CO and CO2, or with non-oxygenated functional groups to yield hydrocarbon gases. This study further examined the influence of reaction temperature and gasifying agents on the co-gasification process, discovering that elevating the reaction temperature and utilizing steam as the gasifying agent could significantly increase the H2/CO ratio. These findings provide valuable guidance for the optimization of gasification reaction control and the selection of appropriate processes in practical applications.

Keywords: sewage sludge, bituminous coal, gasification, ReaxFF-MD