温度梯度对生物质气流床气化产物的影响OA北大核心CSTPCD

Gasification temperature is a crucial parameter influencing the gasification per-formance of biomass.However,the achievement of efficient biomass gasification is hindered by the uneven temperature distribution in industrial gasifiers.To prevent or mitigate the adverse effects of uneven temperature distribution and enhance biomass gasification performance,the influence of axial temperature gradient(ATG)on the three-phase products of biomass gasifica-tion was investigated experimentally in this study.The axial temperature gradient in the flame zone of an industrial gasifier was simulated by setting the temperature difference between two sections of the drop tube reactor,where the upper section remained at 1 300℃and the lower sec-tion ranged from 900℃to 1 300℃.The gasification characteristics of pine sawdust were ana-lyzed experimentally with carbon conversion and cold gas efficiency as the evaluation indexes.The results show that the effective gas(CO+H2)yield,carbon conversion and cold gas efficien-cy of syngas gradually decrease with the increase of ATG in the range of 100℃-300℃.The char yield is consistently lower than 0.2%,indicating almost complete gasification of char in the high-temperature zone(1 300℃)of the upper section of the gasifier(450 mm).Soot is the primary solid carbon-containing product of biomass high-temperature fluidized bed gasification.The soot yield is about 3-6 times higher than that of char,which is difficult to be completely removed.When the ATG of the upper and lower sections exceeds 300℃,the gas-phase homogeneous re-forming and gas-solid heterogeneous reaction almost ceases in the low-temperature region of the lower section,with the product yield,carbon conversion and cold gas efficiency remaining nearly unchanged.At the same time,a small amount of tar production,comprising around 0.01%,is detected.