CuO/Al2O3作为载氧剂的流化床化学链燃烧数值模拟

以欧拉-欧拉双流体模型和气固非均相化学反应动力学为基础,嵌入了气固化学反应速率方程和反应内热源项的UDF(自定义函数)程序,对化学链燃烧燃料反应器——鼓泡流化床内气固两相流动及化学反应过程进行了数值模拟,并分析了甲烷进气速度对床内气固两相流动、传热及化学反应速率的影响.结果表明:随着甲烷进气速度增加,床内气固混合更加剧烈,气泡的产生、碰撞和破碎使得气固分布不均,流化质量下降,导致反应器内化学反应速率以及温度分布不均,床内局部存在的高温区域将使颗粒温度过高而烧结,降低了甲烷燃烧效率.

Numerical Simulation of Fluidized Bed Chemical Looping Combustion Using CuO/Al2O3 as Oxygen Carrier

Based on the Eulerian-Eulerian bi-fluid model and the kinetic model of the gas-solid heterogeneous chemical reactions,by adding the UDF(user defined function) code into Fluent 6.3 flow solver to integrate the chemical reaction mechanism and heat source term,the gas-solid flow processes and chemical reactions of the chemical looping combustion in the fuel reactor—the spouted fluidized bed were modeled.The influences of methane gas inlet velocities on gas-solid flow feature,heat transfer and chemical reaction rates were analyzed. With an increasing methane inlet velocity,the gas and solids are found to be mixed more intensely and the uneven distribution of gas-solid,lower quality of fluidization,and non-uniform chemical reaction rates and temperature will take place due to the formation,collision and burst of the bubbles.It is also found that there are some spots of higher temperature in local regions,which may lead to particles agglomeration and lower efficiencies of methane combustion.