670 MW对冲旋流燃烧锅炉防高温腐蚀试验研究

Experimental Research on Treatment of High Temperature Corrosion in a 670 MW Opposed Firing Boiler

针对锅炉低氮燃烧改造后水冷壁近壁区发生高温腐蚀的问题,以某电厂670 MW超临界对冲旋流燃烧锅炉为研究对象,通过贴壁风系统改造结合燃烧优化调整试验,分析了贴壁风门开度、运行氧量、煤质变化等参数对水冷壁近壁区还原性气氛和炉内燃烧及运行参数的影响。结果表明:增加贴壁风系统后,水冷壁近壁区O2体积分数明显提高,CO体积分数平均值下降65.4%,H_(2)S体积分数平均值下降53.2%,H_(2)S平均值可控制在0.1×10^(-3)以下,缓解高温腐蚀效果显著;高温腐蚀主要发生在高负荷工况,提高运行氧量有助于缓解高温腐蚀风险;增设贴壁风系统对锅炉氮氧化物排放量影响较小。

Aiming at the problem of high temperature corrosion in the near wall area of the water wall af⁃ter low nitrogen combustion transformation of the boiler,taking a 670 MW supercritical opposed firing boiler as an research object,through the modification of the closing⁃to⁃wall air system combined with the combustion optimization adjustment test method,the influence of the closing⁃to⁃wall air damper opening,the operating oxygen content and the change of coal quality parameters on the reducing atmosphere,fur⁃nace combustion and operating parameters in the near wall area of the water wall was analyzed.Results show that after adding the closing⁃to⁃wall air system,the oxygen volume fraction increases significantly,the average CO volume fraction decreases by 65.4%and the average H_(2)S volume fraction decreases by 53.2%,and the average H_(2)S volume fraction can be controlled below 0.1×10^(-3),so the effect of reduc⁃ing high temperature corrosion is expected to be remarkable;high⁃temperature corrosion mainly occurs in the case of high unit load,increasing the amount of operating oxygen helps to alleviate the risk of high temperature corrosion;adding the closing⁃to⁃wall air system has little affect on the NOx emission of boiler.