氮气流量对稻草热解半焦性能的影响

Influence of nitrogen flow rate on the semi-char characters of straw pyrolysisstraw pyrolysis

慢速热解方法作为生物质气流床气化的前处理工艺,可以解决生物质在气流床气化过程中能量密度低、物料输送难度大及焦油含量高等问题,也可以提高气化合成气的热值。在热解过程中改变氮气流量,考察反应过程的固体产率、能量产率、半焦热值及半焦中碳、氧元素含量的变化结果。研究表明:当氮气流量为0.006m3/h时,固体产率和能量产率最高;当氮气流量为0.16 m3/h时,半焦热值和半焦中碳元素含量的增加量最大,但从整个生物质气流床气化工艺考虑,氮气流量应采用0.006 m3/h。

Slow pyrolysis is the pre-treatment technology of biomass entrained-flow gasification. The purpose of slow pyrolysis is to solve the problems of low energy density of biomass, the difficulty of conveying biomass and the high tar content during the entrained-flow biomass gasification process; meanwhile, it can increase the higher heating value of syngas. By changing the nitrogen flow rate for straw pyrolysis, we studied the changes of solid yield, energy yield, heating value of semi-char and the contents of carbon and oxygen in semi-chars. From the results, the solid and energy yields are the highest when the nitrogen flow rate is 0.006 Nm^3/h; but the heating value of semi-char and the increment of carbon in semi-char are the highest when the nitrogen flow volume is 0.16 Nm^3/h. However, the nitrogen flow rate should be 0.006 Nm^3/h considering the whole biomass entrained-flow gasification process.