为确定燃烧解耦双流化床气化的气化反应条件和气化反应器的设计.在直径60 mm 和高700 mm的小型流化床反应器中,采用粒径8 mm 以下的锅炉烟煤以间歇气化方式在1133 K 的条件下,研究了进料方式、气化剂中水蒸汽和 O_2含量、以及煤料粒径等因素对煤气化生成燃气反应过程的影响.重点考察了各因素对煤转化速率的作用规律。综合各因素对 C 转化为燃气的速度、最大 C 转化率及生成气热值的影响趋势,确定了适宜的煤气化操作条件为:从流化颗粒表面附近加料.气化剂中 O_2体积分率5%、水蒸汽体积分率35%,煤粒径小于5 mm。在该条件下。实现60%的 C 转化为燃气所需要的停留时间大致为600 s。
Various process residues represent a kind of biomass resource already concentrated but containing water as much as 60 wt.%.These materials are generally treated as waste or simply combusted directly to generate heat.Recently,we attempted to convert them into middle caloric gas to substitute for natural gas,as a chemical or a high-rank gaseous fuel for advanced combustion utilities.Such conversion is implemented through dual fluidized bed gasification(DFBG).Concerning the high water content of the fuels,DFBG was suggested to accomplish either with high-efficiency fuel drying in advance or direct decoupling of fuel drying/pyrolysis from char gasification and tar/hydrocarbon reforming.Along with fuel drying, calcium-based catalyst can be impregnated into the fuel,without much additional cost,to increase the fuel’s gasification reactivity and to reduce tar formation.This article reports the Ca impregnation method and its resulting effects on gasification reactivity and tar suppression ability.Meanwhile, the principle of directly gasifying wet fuel with decoupled dual fluidized bed gasification(D-DFBG)is also highlighted.
