建立了基于CFD的三维非稳态喷动流化床煤气化动力学模型.此模型包含气固流动模型,煤的挥发分析出模型,焦炭气化反应模型和气相间的均相反应模型等子模型.焦炭的非均相反应速率由气体扩散和化学反应动力学共同控制.气体均相反应可以作为二级反应来处理.将试验结果和模拟的计算结果进行了对比,结果表明,入口中心喷动区的温度最高,温度场沿床高方向逐渐降低.煤气质量在加压后有了明显提高.验证的结果表明此CFD模型可以用来预测煤气化的反应过程.
A 3 D unsteady mathematical model has been developed to simulate the coal gasification process in a pressurized spout-fluid bed. This CFD model is composed of gas-solid hydrodynamics, coal pyrolysis, char gasification and gas phase reaction sub-models. The rates of heterogeneous reactions are determined by Arrhenius rate and diffusion rate combined. The homogeneous reactions of gas phase can be treated as secondary reactions. A comparison of the calculation and experimental data shows that most gasification performance parameters can be predicted accurately. The highest temperature occurs at the central jet near the outlet of nozzle, and temperature decreases along the gasifier. High pressure increases coal gasification performance. The good agreement of the calculation and experimental data indicates that CFD modeling can be used to predict the coal gasification process in a complex fluided bed.