The crucial role of deoxygenation in syngas refinement and carbon dioxide utilization during chemical looping-based biomass gasification

Reducing anthropogenic CO 2 emissions has become a primary environmental concern for the present society, making the development of energy-efficient, net-negative CO 2 emitting technology paramount. Here, the Chemical looping deoxygenated gasification (CLDG) process is experimentally conducted to demonstrate the crucial role of deoxygenation on syngas refinement and CO 2 utilization via Fe 0  ↔ Fe 3+ looping. A reduction of 0.324 g CO 2 per gram pine wood biomass gasified is achieved, a 288% reduction in CO 2 emissions compared with that of biomass conversion without deoxygenation. The superiority of CLDG can be also reflected in syngas yields increased by 16.37% and a CO 2 concentration decreased by 44.16%. Results from the heat balance calculation indicate that both the gasifier and the regenerator are endothermic, which cannot achieve the auto-thermal operation of CLDG, thus requires an extra energy supply source. Density functional theory calculations elucidate that the active site of CO 2 adsorption is located at the three-phase interface of CaO(1   1   1), Fe(1   1   0), and amorphous carbon (AC). It is anticipated that CLDG has the potential to serve as an effective measure for reducing CO 2 emissions while promoting syngas yield and quality.