缝隙式喷口600MW超临界W火焰锅炉改造前后燃烧特性的试验与数值计算研究

Experimental and Numerical Studies on Combustion Characteristics of a 600 MW Supercritical Arch-fired Boiler Equipped With Slot Burners Before and After Retrofit

对一台缝隙式喷口600MW超临界W火焰锅炉进行改造,并对改造前后的燃烧性能进行了现场测试和数值模拟研究。试验结果表明:改进煤粉浓淡分离方式、优化风率分配和喷口结构可以提高浓相侧煤粉浓度,显著缩短浓相侧煤粉气流着火距离,减小火焰下冲深度,降低冷灰斗区域温度。数值计算进一步发现结构和运行参数优化后锅炉整体流场分布更为对称,颗粒大部分集中于浓相侧。燃烧器分开布置后沿炉膛宽度方向输入热量更加均衡,有利增强锅炉运行的安全性。

Experimental and numerical studies were conducted on the combustion characteristics of a 600 MW supercritical arch-fired boiler equipped with slot burners before and after retrofit. The experimental measurements reveal that pulverized coal concentration of fuel-rich flows increased by improving the primary air separation devices, air distribution and nozzle structure design. The ignition distance of the fuel-rich flows and the depth of flame traveling path became remarkably shorter, and flame temperature in the hopper region decreased. Numerical simulation further found that the aerodynamic field in the furnace was more symmetric and most of the pulverized coal particles were concentrated in the dense phase. Heat release along the furnace width was more uniform when distance between two burners increased, and thereby the operational safety of the boiler was enhanced.