Biomass gasification characteristic in an auto-thermal fixed-bed gasifier using air and O2-enriched air

A fixed-bed gasifier presented here was used to obtain fundamental data for use in industrial-scale biomass gasifiers operating with air or O-2-enriched air. This study investigated two different gasifying agents (air or O-2-enriched air) for the gasification of pine wood particles. Air gasifying agent provided the effect of varying air flow rates on gasification performance. In contrast, O-2-enriched air provided the effect of different O-2 concentrations on gasification performance at a constant gasifying agent flow rate. The effect of gasifying agent on the syngas composition, gas yield, overall equivalence ratio, oxidation layer temperature, gasification rate, and cold gasification efficiency are reported here. The focus was on how variations in gasifying agent conditions affect the biomass gasification. The results obtained provide the advantages and differences of these two gasifying agents on the gasification modes. The results revealed that gasification agent flow rate of <40 l/min are favorable for air assisted gasification. Increase in oxygen concentration from 21 % to 28 %, reduced the N-2 concentration from 54.22 % to 38.87 %, increased the LHV from 4.29 to 6.67 MJ/Nm(3), and gasification rate from 21.21 to 50.39 g/min. Increase in gasifying agent flow rate and O-2 concentration enhanced the gasification rate. The amount of O-2 consumed in O-2-enriched air gasification mode was low. In auto-thermal gasification, effective management of biomass gasification rate through adjustments of the gasifier flow rate and O-2 concentration can help provide an important role in scale-up of the technology.