Shell沥青气化超高压废热锅炉本体大法兰泄漏原因分析及解决措施

CAUSE ANALYSIS AND SOLUTION OF LA RGE FLANGE LEAKAGE OF THE MAIN BODY IN SHELL ASPHALT GASIFICATION ULTRA-HIGH PRESSURE WASTE HEAT BOILER

POX装置超高压废热锅炉自开工投用以来,本体大法兰多次出现泄漏.通过对其法兰焊唇密封失效原因进行分析,确认密封失效与唇形焊环装配偏差大、焊缝存在缺陷和大法兰螺栓预紧力不足有关.螺栓预紧力不足为失效的主要因素.2015年底,在废热锅炉更换盘管时同步更换了焊唇密封,并通过改进焊唇密封组装程序和焊接工艺、定期组织预紧螺栓等技术措施,彻底解决了该问题.更换焊唇密封后,至今本体大法兰再未发生过泄漏事故.

Since the ultra-high pressure waste heat boiler of POX unit was put into operation,leakage has occurred in the large flange of the.main body many times.By analyzing the reasons for the failure of the flange welding lip seal,it was confirmed that the sealing failure was related to three factors,namely:the large.assembly deviation of the lip welding gasket,defective gasket welds and insufficient bolt pre-tightening force.The main factor for the failure was insufficient bolt pre-tightening force.At the end of 2015,the welding lip seal was replaced synchronously when the coil was replaced in the waste boiler.By improving the welding lip seal assembly process and welding process,and pre-tightening the bolts regularly,the problem was solved completely.After replacing the welding lip seal,there has been no leakage accident in the large flange of the main body so far.