Experimental microwave-assisted air gasification of biomass for syngas production

Syngas production from biomass is a clean way to supply energy for our economy and society. In this study, a microwave-assisted air gasification system was developed and the preliminary results of syngas yields, syngas compositions, syngas lower heating values (LHVs), carbon conversion efficiencies, and cold gas efficiencies obtained from corn stover (CS) gasified at varied air flow rates (200, 400, and 600 mL/min), gasification temperatures (500, 600, and 700 °C), and retention times (10, 20, and 30 min) were reported for the first time. The results showed that the increase in air flow rate increased the syngas yield and carbon conversion efficiency, decreased the syngas LHV whereas first increased then decreased the cold gas efficiency. Higher gasification temperature favored the syngas yield, syngas LHV, carbon conversion efficiency and cold gas efficiency. Longer retention time favored the syngas yield and carbon conversion efficiency whereas lowered the syngas LHV and cold gas efficiency. Syngas yield of 38.90–76.14 wt% and LHV of 4.95–6.34 MJ/m3 were observed for the syngas at air flow rate of 200–600 mL/min, gasification temperature of 500–700 °C and retention time of 10–30 min. The most significant contribution of this study is the high syngas yield, which is even higher than that from a microwave-assisted pyrolysis process at a high temperature of 900 °C.