喷嘴结构对粉煤气化过程影响的数值模拟

为研究气化喷嘴对气流床干煤粉气化炉气化过程的影响规律，并对喷嘴结构进行优化，针对具有不同煤粉通道旋转角θ和旋流叶片安装角度α值气化喷嘴的气化炉建立三维模型并进行数值模拟。通过冷态模拟发现：气化室内流体的速度场主要受α值的影响，而θ值对气化室内煤粉颗粒的质量浓度影响更加明显。当θ=60°、α=30°时，煤粉颗粒的弥散性最好，气化室内流体的速度分布、煤粉颗粒的质量浓度以及气化剂分布更加均匀，有利于气化炉气化效率的提高。取喷嘴结构参数θ=60°、α=30°的模型进行气化过程热态模拟，辐射传热采用P-1模型、湍流-化学反应过程采用EDC模型、脱挥发分采用Two-Competing Rates模型。模拟结果显示，该喷射条件下气化室内的流场分布好，气化效率高，合成气有效气组分CO+H₂总摩尔分数达到91.6%，碳转化率达到98.11%。

Numerical Simulations of Effects of the Nozzle Structure on Pulverized Coal Gasification Process

To study the effects of the gasification nozzle on the gasification process and to optimize nozzle structure, the 3D geometric models of gasification nozzle and chamber were established with different pulverized coal passage rotation angle θ and swirling vane installation angle α value. Through the cold simulations, it is found that the velocity distribution of fluid in the gasification chamber is mainly affected by αvalue, and the mass concentration of coal particles is affected more obvious by θ value. When θ=60°and α=30°, the dispersion performance of coal particles is the best, and the velocity distribution of the fluid, the mass concentration of coal particles and gasifying agent become better in the gasification chamber, which are beneficial to increase the gasification efficiency. The gasification process was simulated for the optimal model, the P-1 model, EDC model and two-competing-rates model were used as the thermal radiation model, turbulent-chemical reactions and devolatilization model. The results show that the flow field distribution is good in the gasification chamber and the gasification efficiency is better. The total mole fraction is 91.6% for CO and H₂, the carbon conversion efficiency is 98.11%.