Ultra-low carbon dioxide emissions for biomass gasification using air with nearly 100% CO₂ capture and conversion

Addressing the high CO₂ emissions from biomass gasification is crucial for enhancing the sustainability and environmental profile of this technology. This work proposes a novel approach by integrating the biomass gasification process with carbon capture and utilisation (IGCCU), to tackle the substantial challenge of traditional biomass gasification, which leads to high CO₂ emissions. Specifically, during the biomass gasification stage, this novel approach successfully captured 14.39 mmol g⁻¹_lignin of CO₂, based on benchmark conditions. The captured CO₂ is subsequently converted into CO during the hydrogenation stage, achieving a peak CO concentration of 1.58 %. The results reveal that maintaining a marble feeding mass of 6 g and setting the reaction temperatures for gasification, carbon capture, and hydrogenation at 500 °C, 400 °C, and 550 °C, respectively, consistently ensures ultra-low CO₂ emissions throughout the entire process. “Ultra-low CO₂ emissions” specifically refers to the absence of CO₂ signals throughout the entirety of the IGCCU process, encompassing stages such as biomass gasification, CO₂ capture, and CO₂ conversion. Notably, CO₂ conversion and CO selectivity remain at a stable 100 % level over 8 cycles as only CO was generated during the hydrogenation stage, underscoring the excellent stability of this novel technology. Furthermore, the utilisation of low-cost sorbent material (waste marble powder) and the readily available biomass gasification agent (air) enhance the economic feasibility of this new technology while demonstrating robust resistance to carbon deposition.