Effect of gasifying agents on sawdust gasification in a novel pilot scale bubbling fluidized bed system

Effect of gasifying agents, such as air, oxygen-enriched air, air-steam, and oxygen-steam, on sawdust gasification was investigated in a novel pilot scale bubbling fluidized bed gasification system. The results showed that gasifying agents had a significant effect on gasification performance and producer gas properties. H-2 content in the producer gas increased as equivalence ratio (ER) increased from 0.20 to 0.30 for all gasifying agents used. CO, CH4, and C(n)H(m )decreased and CO2 presented two different trends as ER increased from 0.20 to 0.30, resulting in lower heating value decreasing, gas yield increasing, carbon conversion efficiency and cold gas efficiency change. Compared to sawdust gasification using air only, oxygen-enriched air increased lower heating value due to reducing N-2 dilution, air-steam favored H-2 production because of enhancing water gas shift reaction, and oxygen-steam took both advantages of N(2 )free and steam addition. The maximum value of the H-2/CO ratio was 1.44 by using air-steam and oxygen-steam as the gasifying agents at the ER of 0.30.