尿素水解制氨装置法兰失效原因分析  

Failure analysis of flange used for urea hydrolysis equipment

作　　者：黄锦阳[1] 杨征[1] 鲁金涛[1] 张波[1] 杨珍[1] 徐宏杰[1] 

机构地区：[1]西安热工研究院有限公司,陕西西安710032

出　　处：《热力发电》2016年第6期111-115,共5页Thermal Power Generation

基　　金：国家自然科学基金项目(51301130;51401163);华能国际电力股份有限公司科技项目(ZA-14-HKR01)

摘　　要：针对现役烟气脱硝用尿素水解装置中氨气出口密封法兰失效问题,采用宏观检验、金相分析、扫描电镜和X-射线衍射等方法,对TP304不锈钢材料密封法兰失效原因进行了分析。结果表明:法兰腐蚀失效主要是由尿素水解后高温高压中间产物引起的持续性点蚀和溶解腐蚀导致;腐蚀产物以Fe和Cr的氧化物为主,其结构疏松,存在大量孔洞和裂纹;TP304不锈钢不适宜用作烟气脱硝用尿素水解装置氨气出口密封法兰材料。By such tests as macroscopic inspection,metallographic analysis,scanning electron microscope（SEM）and X-ray diffraction（XRD）,the failure behavior of a seal flange made by TP304 stainless steel used at outlet of the urea hydrolysis equipment for flue gas denitrification was analyzed.The results show that,the failure of the flange plate was mainly caused by the continuous pitting corrosion and dissolved corrosion in high temperature and pressure urea corrosive medium.The interface between the corrosive medium and flange plate was serrated and the corrosion products were mainly Fe and Cr oxides.Loose structure and a large number of holes and cracks appeared in the corrosion products.The TP304 austenitic stainless steel is unsuitable for the seal flange material for urea hydrolysis equipment in flue gas denitrificaiton.

关 键 词：烟气脱硝 尿素水解 法兰 腐蚀 失效 点蚀 TP304不锈钢 

分 类 号：TG172.82[金属学及工艺—金属表面处理]