纯烧准东煤CFB锅炉的受热面腐蚀原因分析

Analysis on Corrosion Causes of Heating Surface of CFB Boiler Burning Zhundong Coal

基于220 MW纯烧准东煤循环流化床锅炉,研究关于纯烧准东煤引起管道积灰和腐蚀的原因。通过改善入炉煤煤质以优化锅炉机组的运行状态,对锅炉机组腐蚀管道取样进行了力学性能测试,明确了造成失效的原因。管道壁面沉积灰取样分析,明确了沉积灰的主要成分和主要元素;通过分析得到煤中钠、钾、钙等元素与硫元素反应生成的硫酸盐是造成管壁积灰的主要原因;同时在燃烧中形成的硫酸盐和氯盐是也引起管道腐蚀泄露的重要原因,并且氯腐蚀在氯盐和氧分压充足的条件下,可形成一个循环,会加剧管道的腐蚀;在全烧准东煤时应注意控制掺配黄沙比例,可有效地降低锅炉受热面发生氯腐蚀。研究结果可为循环流化床锅炉纯烧准东煤的腐蚀控制问题的解决提供参考。

Taking 220 MW pure fired Zhundong coal circulating fluidized bed boiler as the research objective,the causes of pipeline ash deposition and corrosion caused by pure combustion of Zhundong coal are then analyzed.The operation state of the boiler unit is optimized by improving coal quality.Test the mechanical properties of corroded pipes of the boiler unit to determine the cause of failure;Sample and analyze the ash on the pipe wall to determine the main components and composition of the ash.It is found that the main cause of ash accumulationon the pipe wall is the reaction of sodium,potassium, calcium and sulfur in coal which forms sulfate;At the same time, sulfate and chlorine salt formed during combustion are also important reasons for pipeline corrosion leakage. When the partial pressure of chlorine salt and oxygen is sufficient, chlorine corrosion will form a cycle and aggravate pipeline corrosion. When fully burning Zhundong coal, attention should be paid to the proportion of sand in order to reduce chlorine corrosion on the boiler heating surface. The research results can provide refer⁃ ence for the corrosion control of Zhundong coal in circulating fluidized bed boiler.