Waste-gasification efficiency of a two-stage fluidized-bed gasification system

摘要

This study employed a two-stage fluidized-bed gasifier as a gasification reactor and two additives (CaO and activated carbon) as the Stage-Ⅱ bed material to investigate the effects of the operating temperature (700 ℃, 800 ℃, and 900 ℃) on the syngas composition, total gas yield, and gas-heating value during simulated waste gasification. The results showed that when the operating temperature increased from 700 to 900 ℃, the molar percentage of H_2 in the syngas produced by the two-stage gasification process increased from 19.4 to 29.7 molSt and that the total gas yield and gas-heating value also increased. When CaO was used as the additive, the molar percentage of CO_2 in the syngas decreased, and the molar percentage of H_2 increased. When activated carbon was used, the molar percentage of CH_4 in the syngas increased, and the total gas yield and gas-heating value increased. Overall, CaO had better effects on the production of H_2, whereas activated carbon clearly enhanced the total gas yield and gas-heating value.