气化温度是影响生物质气化性能的重要参数,而工业气化炉内温度分布不均匀,阻碍了生物质高效气化的发展进程。为了预防或减少温度分布不均所造成的不良影响,提高生物质气化性能,通过实验方法研究了炉内温度梯度(axialtemperaturegradient,ATG)对生物质气化三相产物的影响。实验设定落下床的上段炉温为1300℃不变,下段炉温范围为900℃~1300℃以模拟工业气化炉火焰区存在的轴向温度梯度,以碳转化率和冷煤气效率为评价指标,对松木屑的气化特性进行了实验分析。结果表明:在ATG为100℃~300℃范围内,合成气中有效气体(CO+H2)产率、碳转化率和冷煤气效率随着ATG的增大而逐渐减小。半焦产率均低于0.2%,表明松木屑在上段炉(450mm)1300℃高温区域内几乎实现了半焦的完全气化。碳烟为生物质高温气流床气化的主要含碳固体产物,其产率为半焦产率的3~6倍,且难以被完全清除。当上下两段的ATG高于300℃时,气相均相重整和气-固非均相反应在下段低温区几乎停滞,产物产率、碳转化率和冷煤气效率几乎保持不变,同时有少量焦油生成,占比约0.01%。

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 ℃ and the lower sec-tion ranged from ℃ to ℃. 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 ℃. The char yield is consistently lower than 0.2%, indicating almost complete gasification of char in the high-temperature zone (1 ℃) 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 times higher than that of char, which is difficult to be completely removed. When the ATG of the upper and lower sections exceeds ℃, 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.