催化装置高温烟道膨胀节开裂分析及改进

Analysis of cracking of expansion joint of high-temperature flue gas stack of FCCU and improvement measures

中国石油化工股份有限公司金陵分公司1.30 Mt/a重油催化裂化装置的高温烟道膨胀节在2010年8月至2013年3月期间,相继发生了13次开裂。从开裂处材料和断口形式等进行分析,判定该合金断裂属高温晶界开裂。采取的改进措施有:将原材料升级为Inconel625,提高材料强度和性能;结构改造,避免雨雪天气对膨胀节运行的不利影响;设计优化管系布置,将膨胀节所在高温管系的立体"Z"型布置分解成两个"L"平面型管系,提升高温烟道中膨胀节的可靠性。改造后的高温烟道及膨胀节节约了包套的维修费用,提高了烟机机组连续做功效益,减少了非计划停工费用,合计约数百万元,取得了预期的效果。

From August 2010 to March 2013,the expansion joints of high-temperature flue gas stack cracked 13 times in heavy oil fluid catalytic cracking unit with an annual production capacity of 1.3 MM TPY in Sinopec Jinling Company.The material analysis of the cracking part and fracture analysis,etc concluded that the cracking of the alloy was the high temperature grain boundary cracking.The following improvement measures were adopted such as：the material was upgraded to Inconel 625 to improve the strength and performance of the material,the structure was revamped to avoid the negative impact of rainy and snowy climate on the expansion joint,the piping system arrangement was optimized in the design and ＂Z＂ type arrangement of high-temperature pipeline connecting with expansion joints was divided into two ＂L＂ layouts to improve the reliability of expansion joints in high-temperature stack.The revamped high-temperature flue gas stack and expansion joints have saved millions of Yuan RMB by saving the costs of maintenance and costs of unscheduled shutdown of the unit and generating the benefit by the continuous operation of the flue gas expander.