Biomass gasification: Sub-pilot operation of >600 h with extensive tar cracking property and high purity syngas production at H2:CO ratio-2 using moving bed redox looping technology

Commercializing biomass-based technologies as an alternative to fossil fuels is necessary for a sustainable future. This study proposes a robust Biomass to Syngas (BTS) chemical looping system to gasify biomass into syngas for a range of downstream applications, with focus on liquid fuel production. The system has been demonstrated on a sub-pilot scale cumulatively for over 600 h, proving the technology's commercial viability. Pelletized corn cob, woody pellets, and unpelletized loose corn cob, were successfully tested, proving the robusticity of the process to handle untreated biomass with batch variation. Tar analysis shows that moving bed reducer can reduce the tar concentration to 0.5 g/m(3), owing to uniform residence time, high temperature, and catalytic activity of oxygen carrier, while injection of steam as an enhancer gas increases carbon conversion by char gasification. A variable syngas quality with an H-2/CO ratio of similar to 2 and a syngas purity greater >70% was achieved, making this syngas suitable for the generation of liquid fuels via Fischer-Tropsch synthesis. The biomass requirement for a chemical looping system decreases by 13.9% over the conventional biomass gasifier for generating the same amount of liquid fuels. Heat integration suggests integrating biomass drying with the combustor exhaust air for process authothermicity.

Automated summary

This study proposes a robust Biomass to Syngas (BTS) chemical looping system for gasifying biomass into syngas, suitable for liquid fuel production. The system has been demonstrated successfully on a sub-pilot scale, proving its commercial viability. The system can effectively reduce tar concentration, achieve high-quality syngas, and decrease biomass requirement compared to conventional biomass gasifiers.