Thermal arc air plasma application for biomass (wood pellets) gasification

Plasma technologies have drawn attention as a possible way for biomass/waste conversion into valuable intermediate products, which could partially satisfy the growing energy demands. Thus, this experimental research aimed to determine the ability to gasify wood pellets to synthesis gas in the thermal air plasma environment. The influence of the plasma torch power, plasma-forming gas flow rate, and the equivalence ratio on biomass gasification was analyzed. The synthesis gas generation varied between 59.95 and 62.51%, while the H-2/CO ratio ranged from 0.68 to 0.8. The producer gas's highest H-2 and CO concentrations were 26.6 and 33.35%, respectively, giving the H-2/CO ratio of 0.8. The lower heating value of the produced synthesis gas ranged from 7.62 to 8.82 MJ/Nm(3). The carbon conversion efficiency and the energy conversion efficiency were equal to 85.3-97.2% and 29.23-30.57%, respectively. The specific energy requirements varied between 165.47 and 195.61 kJ/mol of synthesis gas. Moreover, the energy and mass balance evaluation showed that generated producer gas could produce 15-18 kWh and 111-114 kWh of electrical and thermal energy, respectively, when 20.73 kg/h of wood pellets is gasified. Also, 28 and 33% of the electricity required for the air plasma formation can be received using producer gas in an internal combustion engine and microturbine.