600 MW燃用褐煤墙式切圆锅炉运行中存在的问题分析及优化措施

Analysis of Problems and Optimization Measures in the Operation of 600 MW Lignite-fired Wall Tangential Circle Boiler

对某台采用四墙布置燃烧器切圆燃烧的600 MW超临界锅炉进行了优化调整试验和数值模拟,对锅炉存在的水冷壁严重结焦、超温爆管、炉膛出口速度及烟温偏差问题的原因进行了研究。结果表明:锅炉炉膛出口左、右侧存在速度与烟温偏差,燃尽风的投切对炉膛出口气流速度分布影响很大;提高一次风率对提高制粉系统出力有利,但过高的一次风率(40%以上)是导致锅炉发生水冷壁结焦和局部超温爆管的主要原因;一次风率控制在设计值36%左右,锅炉的运行状态明显改善。

Optimization tests and numerical simulations were conducted on a 600 MW wall-tangential-circle supercritical boiler,to investigate the causes of severe slagging on water-cooled walls,tube rupture due to overheating,and deviations in furnace outlet velocity and flue gas temperature.The results show that velocity and temperature deviations exist on the left and right sides of the furnace outlet;the cutting off and feeding of the separated over-fire air(SOFA)significantly impacts the velocity distribution of the furnace outlet airflow;increasing the primary air ratio improves the output of the pulverizing system,but excessive primary air ratio(over 40%)is the main cause of slagging,local overheating and rupture of the water-cooled wall tubes;controlling the primary air ratio around the design value of 36%significantly improves the operation condition of the boiler.