关键词: 生物质气化, 膜反应器, 碳基催化剂, 清洁合成气

Abstract:

Under the "Dual Carbon" initiative, biomass stands out as a zero-carbon or even negative carbon resource with significant development potential. Through pyrolysis and gasification technologies, biomass can be transformed into syngas, which serves as a feedstock for fuel cells or can be further converted into high-value products such as methanol, dimethyl ether, and aviation fuel. However, the presence of tar and particulate matter (PM) in syngas represents a major challenge in its downstream processing. In traditional biomass gasification systems, the gasification, tar cracking/reforming, and gas-solid separation units operate independently. As a consequence, the raw syngas has to be cooled down to a temperature below 300℃ to match the operating temperature conditions of the dust removal equipment. This cooling process gives rise to issues including tar condensation and blockage, equipment corrosion, and heat loss. To tackle these challenges, this study introduces a novel approach that employs a membrane reactor integrated with a catalyst for the in-situ purification of syngas during poplar wood gasification. Silicon carbide (SiC) membranes were employed to capture PM, and Fe/Ni-loaded carbon-based catalysts were used to catalyze the cracking/reforming of the tar volatiles. The research revealed that at an optimal temperature of 800℃ and a steam-to-biomass mass ratio (S/B) of 1.5, employing a SiC membrane reactor in conjunction with activated carbon-based catalysts loaded with Fe-Ni, the yield of syngas was 56mmol/g, and the molar ratio of hydrogen to carbon monoxide in the syngas was approximately 1.9; the tar yield from the gasification of poplar wood was reduced to 8.4g/m³ of syngas, with a tar conversion of 91.6%; the production of PM was minimized to 0.08g/m³ of syngas, and the PM removal efficiency was 89.0%, aligning with the technical specifications for syngas used in solid oxide fuel cells.

Key words: biomass gasification, membrane reactor, carbon-based catalyst, clean syngas