多孔壁风耦合空气分级条件下煤粉燃烧过程中硫演化的数值模拟

Numerical Simulation on Sulfur Evolution in Pulverized Coal Combustion Under Multi-hole Wall Air Coupling with Air Staged Technology

为研究多孔壁风对煤粉锅炉高温腐蚀的影响,并验证含硫组分气相反应机理模型的可靠性,利用Ansys Fluent软件开展了多孔壁风耦合空气分级条件下煤粉燃烧过程中硫演化的数值模拟研究。结果表明:SO2、H2S、CS2和COS等体积分数的计算值与实验值的误差在18%以内,该机理模型可用于实际工程中含硫组分演化的预测;适量的多孔壁风可以在主燃区和还原区壁面上形成一层氧化性气膜,阻止腐蚀性组分接触壁面;综合考虑NOx排放量、燃烧效率和高温腐蚀问题,燃烧器空气系数为0.80时对应的多孔壁风系数的优化值为0.05。

To investigate the impact of multi-hole wall air on high-temperature corrosion and to test the model reliability for gas phase reaction mechanism of sulfur components, numerical simulations were carried out on the sulfur evolution in pulverized coal combustion under multi-hole wall air coupling with air staged technology using Ansys Fluent software. Results show that all the errors between predicted and measured values for SO2, H2S, CS2 and COS are within 18%, indicating that the kinetic model can be adopted for the predication of sulfur component evolution in actual engineering;proper amount of multi-hole wall air can form a film of oxidizing gas over the wall in the main combustion and reductive zones, keeping the corrosion components away from the wall. By comprehensively considering the NOx emission, combustion efficiency and high-temperature corrosion of the boiler, the optimal value of the multi-hole wall air ratio is recommended to be 0.05, when the burner air ratio is 0.80.