Biomass gasification to syngas in thermal water vapor arc discharge plasma

This study investigated biomass (wood pellets) gasification to syngas using direct current (DC) thermal arc plasma at atmospheric pressure. Water vapor was used as a main gasifying agent and a plasma-forming gas. The biomass gasification system was quantified in terms of the producer gas composition, the tar content, the H₂/CO ratio, the carbon conversion efficiency, the energy conversion efficiency and the specific energy requirements. It was found that the gasification performance efficiency was highest at the water vapor-to-biomass ratio of 0.97. The producer gas was mostly composed of H₂ (43.86 vol.%) and CO (30.93 vol.%), giving the H₂/CO ratio of 1.42 and the LHV of 10.23 MJ/Nm³. However, high content of tars of 13.81 g/Nm³ was obtained in the syngas. The yield of H₂ and CO was 48.31% and 58.13%, respectively, with the highest producer gas yield of 2.42 Nm³/kg biomass. The carbon conversion efficiency and the energy conversion efficiency were 100% and 48.83%, respectively, and the production of 1 kg of syngas required 1.78 kWh of electric energy input. Finally, the obtained results were compared with different plasma methods, including plasma-assisted application coupled with conventional gasification.