木屑在鼓泡流化床和循环流化床中气化特性的对比研究

Comparison of sawdust gasification in bubbling fluidized bed gasifier and circulating fluidized bed gasifier

对木屑在内径分别为0.3 m×0.3 m的鼓泡流化床气化炉(BFBG)和内径0.4 m的循环流化床气化炉(CFBG)中的气化特征进行了对比,重点考察了当量比对生物质气化特性的影响。实验结果表明,在相同当量比下,由于CFBG操作气速明显高于BFBG,床内强烈的气固传热传质,使得CFBG可以获得较高的热解速率,同时可以使CFBG在较高温度下运行。较高的运行温度不仅有利于二次裂解气化反应,使可燃气体质量明显好于BFBG,同时也减少了燃气中焦油的量。在较低气化当量比下(ER≤0.28),CFBG比BFBG可以获得更高的气体产率、碳转化率和气体效率;在较高当量比下,(ER>0.28),CFBG和BFBG的气体产率、碳转化率和气体效率则相差不大。

The performance of sawdust gasification in a 0.3 m × 0.3 m bubbling fluidized bed gasifier （BFBG） is compared to that in the φ 0.4 m circulating fluidized bed gasifier （CFBG）. The effects of fluidization velocity on the biomass gasification in two fluidized beds were analyzed. Due to the higher fluidization velocity and intensive mass and momentum transfer between gas and solids, CFBG has a faster pyrolysis rate than BFBG and can be operated at higher temperature with the same ER, which facilitates the second gasification and cracking of tar to improve the gas quality and reduce the tar content in gas. At low ER （ ER ≤0. 28 ）, the gas yield, carbon conversion and gasification efficiency of CFBG is higher than BFBG＇ s ; however at higher ER （ ER 〉 0.28 ）, there is little difference between CFBG and BFBG.