流化床中生物质气化的数值模拟

摘要

基于欧拉多相流模型,自编化学反应子模型,通过建立生物质流化床气化动力学模型,对某实验室规模的流化床生物质气化炉进行了数值模拟,研究了蒸汽与生物质的质量比（mS/mB）、生物质粒径对产气组分、蒸汽分解率等的影响.结果表明：mS/mB增大,H2体积分数先上升后保持不变,而CO和CH4的体积分数先下降后几乎不变,蒸汽分解率下降;生物质粒径减小有利于气化过程,使CO和H2的体积分数明显上升;计算结果和试验结果基本吻合,表明基于欧拉多相流的动力学模型能对流化床中生物质的气化进行比较准确的模拟.%Based on Euler multiphase flow models and self-developed chemical reaction models,the dynamical model of biomass gasification in a fluidized bed was set up,with which numerical simulation was carried out to biomass gasification in a lab-scale biomass fluidized bed,so as to study the effect of mass ratio of steam and biomass（mS/mB） and biomass particle size on the gas composition and steam decomposition rate.Results show that with the rise of mS/mB,the volume fraction of H2 rises firstly and then remains unchanged,and that of CO and CH4 decreases firstly and then gets stable,while the steam decomposition rate drops gradually.The reduction of biomass particle size is in favor of the gasification process,which makes the volume fraction of CO and H2 rise.Simulation results basically agree with that of experiments,indicating that the dynamical model based on Euler multiphase flow can be used to simulate the biomass gasification in fluidized bed.