汽车破碎残余物流化床气化特性数值模拟

Numerical simulation of automotive shredder residue gasification characteristics in a fluidized bed

基于CPFD(计算颗粒流体力学)方法,考虑热解、燃烧、气化等反应,构建ASR(汽车破碎残余物)流化床空气气化的三维数值模型,通过气体产物体积分数的模拟结果验证模型的准确性。在此基础上,对ASR气化过程中反应器内的组分分布和流体温度分布进行分析,并探究操作温度、当量比、初始床层高度对ASR气化特性的影响。结果表明:随着操作温度升高,CO和H_(2)的摩尔分数明显增大,气化效率和碳转化率上升,焦油含量下降,950℃时气化效率和碳转化率分别达到67.09%和78.75%;当量比增大可提高气体产率和碳转化率,同时导致气体低热值和气化效率下降;初始床层高度增大促进H_(2)产生,但总体上对ASR气化影响较小。

The three-dimensional numerical model for ASR(automotive shredder residue)air gasification in a fluidized bed was developed based on the CPFD(computational particle fluid dynamics)method,considering pyrolysis,combustion,gasification,and other reactions.The model accuracy was verified by the simulation results of the gas products volume fraction.On this basis,the components distribution and fluid temperature distribution in the reactor during ASR gasification were analyzed,meanwhile,the effects of operating temperature,equivalence ratio and initial bed height on ASR gasification characteristics were investigated.The results show that with the increase of the operating temperature,the mole fraction of CO and H_(2)are obviously enhanced,the gasification efficiency as well as the carbon conversion efficiency are improved,and the tar content is reduced.At 950℃,the gasification efficiency and the carbon conversion efficiency reach 67.09%and 78.75%.Increasing the equivalence ratio leads to greater gas yield and higher carbon conversion efficiency,and results in lower gas low heating value and gasification efficiency.The rise of the initial bed height favors H_(2)production,but has little effect on ASR gasification in general.