循环流化床锅炉返料阀门盖腐蚀失效分析

Failure analysis on corrosion of refeed valve manhole door in circulating fluidized bed boiler

采用光谱仪(OS)、热失重分析仪(TGA)、X射线衍射(XRD)、扫描电镜(SEM)、能谱仪(EDS)等对以石油焦/煤粉为混料燃料的FW型循环流化床(CFB)锅炉返料阀人孔门盖上的表面腐蚀物和穿孔孔洞断口处的宏微观形貌、化学成分、显微组织等进行分析,判定以硬铸铝为基材的人孔门盖发生穿孔是由于烟气中的灰颗粒冲蚀及硫露点腐蚀交互作用共同造成的。根据实际情况,提出相应的预防措施,并建议采用铬镍合金不锈钢取代现用硬铸铝作为门盖基材。

By means of optical spectrometer （ OS ）, thermogravimetric analysis （ TGA ）, X-ray diffraction （ XRD ）, scanning electron microscope （SEM）and energy dispersive spectroscope （EDS） , the corrosives and fracture face of the perforation of refeed valve manhole door in the petrol coke/coal fired FW circulating fluidized bed （CFB）boiler were studied. Finally, based on the analyses results it is shown that, the corrosion perforation was caused by the co-effect of corrosion and abrasion brought by the high S content corrosive particles, prevention methods and the suggestion that, the material of manhole door should be substituted from hard cast aluminum to Cr-Ni stainless steel, were put forward.