超超临界参数锅炉贴壁风改造方案设计及工程应用

Design and Practical Application of Near-Wall Air Retrofit for an Ultra-Supercritical Boiler

针对1台存在严重高温腐蚀问题的660 MW超超临界参数锅炉进行了贴壁风方案设计及工程应用研究。首先,对改造前水冷壁区域的贴壁气氛进行了测试,发现主燃区侧墙处于很强的还原性气氛,是发生严重高温腐蚀的主因。随后,提出了高速直流贴壁风改造方案,在前后墙各布置4层喷嘴,采用一次风为风源,以10°夹角斜向送入高温腐蚀严重的区域,并采用数值模拟对该方案的实施效果进行预测分析。最后,在该锅炉上实施了改造方案,进行了现场实际测试,发现改造后主燃区贴壁O_(2)体积分数度由1.0%大幅提高至2.7%左右,同时CO和H_(2)S浓度分别降低了约70%和85%,效果显著。测试结果还表明,贴壁风系统的投运未对锅炉性能和尾部污染物排放特性产生影响。

Design and practical application study of near-wall air retrofit for a 660 MW ultra-supercritical boiler, which had serious high-temperature corrosion problem, was carried out. First, the near-wall atmosphere at main combustion zone was measured to be strong reductive, which was considered to be the main reason for high-temperature corrosion. Then, a near-wall air retrofit technology solution using high-speed direct jet from primary air system was proposed, including 4 layers of nozzles on the front and rear walls. The near-wall air was connected to the primary air system, and sent to the high-temperature corrosion zone by an angle of 10°. Numerical simulation was performed to verify the effect of the retrofit solution. At last, near-wall air retrofit was implemented in the boiler. The in-situ measurement showed that near-wall O_(2)volume fraction was greatly increased from 1.0% to 2.7%. Correspondingly, CO and H_(2)S concentration was reduced by 70% and 85%. In addition, the experimental results indicated that the application of near-wall air retrofit had no impact on the boiler performance and pollutant emission characteristics.