Research Progress in Biomass Thermochemical Methanation Technology for Synthetic Natural Gas Production

Abstract

Biomass gasification for synthetic natural gas (SNG) production has emerged as a promising pathway for renewable energy utilization and the low-carbon energy transition. This review comprehensively summarizes the key technologies involved in Bio-SNG conversion, focusing on feedstock pretreatment, gasification, syngas conditioning, and methanation. The influences of typical pretreatment methods, including torrefaction and hydrothermal carbonization, on feedstock reactivity and tar formation are critically analyzed. Furthermore, the effects of different gasifier configurations and gasifying agents in regulating syngas quality are compared in detail. The article systematically elaborates the research progress in tar, sulfur, and chlorine impurity removal, water-gas shift (WGS) reaction and H₂ addition through Power-to-Gas (PtG) for H₂/CO ratio adjustment, Ni-based methanation catalysts, and heat-transfer-intensified reactors. Moreover, the inherent limitations and potential improvement strategies of current technologies are discussed, including instability in gasification performance caused by feedstock variability, catalyst deactivation from multiple impurities, coking and sintering during methanation, and thermal management challenges associated with highly exothermic reactions. Finally, Bio-SNG technology is transitioning from individual process optimization toward integrated and synergistic full-process development, which is expected to facilitate the large-scale commercial deployment of this technology.