Production of syngas from oil palm shell biomass using microwave gasification

The research work on microwave gasification (MWG) is limited in the literature compared to pyrolysis, and little attention has been paid to its efficiency. The present study aims to investigate the effect of MW power (20–40 %) and absorber loading (0–15 wt%) on the temperature, gas composition, syngas yield, quality, and efficiencies during gasification of oil palm shell biomass in a 1.25 kW and 2.45 GHz lab-scale microwave (MW) system. Overall, the yield and quality of syngas increased with MW power, but it decreased after reaching optimum absorber loading. The highest product gas (63.3 wt%) with a heating value of 11.66 MJ/m³ was obtained at an optimum process condition (absorber loading of 10 wt% and MW power of 40 %). Under these conditions, the heating rate of 17 °C/s and maximum syngas (CO + H₂) (76.5 vol%) were recorded. The specific energy consumption increased with MW power but dropped with increasing absorber loading, demonstrating MWG to be more energy efficient at higher biomass loading. MW process efficiency (19.7 %) and biomass conversion efficiency (55.6 %) were achieved at optimum process conditions while considering syngas only. The MWG system can become more energy and process-efficient if all byproducts are utilized and scaled up.