Fatigue Failure of Outlet Pipe Work of Flare System at Natural Gas Processing Plant
The natural gas produced from subsea wells is processed through different stages before being supplied through pipelines for local market or export.Processing of the produced natural gas is started with separation of gas and liquid using a slug catcher that is connected to a flare system.The flare system consists of piping made of 16 diameter branches connected to 20 diameter header using circumferential weld with a total of seven joints.The pipe work of the flare system is made of 316L stainless steel and it is operated in an interrupted mode.Design and operation pressures are 142 bar g and 88 bar g while design and operation temperatures are-40℃ and 20℃,respectively.After five years of normal service,one of the seven joints of 16 branch/20 header has experienced failure.Based on different non-destructive and destructive tests,it is concluded that this premature failure is attributed mainly to fatigue damage.It is believed that acute or sharp angle of 16 branch/20 header connection that acts as a local stress raiser played a remarkable role in initiation of fatigue damage on outer surface,just beside circumferential weld.In addition,low stress high frequency vibration of the subject pipe work,due to mainly several emergency shut down operations,has accelerated initiation of fatigue damage.In order to minimize the possibility of such failure in future,design of 16 branch to 20 header connection was modified where a compensation plate fitted was used to minimize stress concentration at this connection zone.
Natural gas processing Flare system 316L stainless steel Stress concentration Vibration Fatigue
Abdel-Monem El-Batahgy Martin Wheeler
Manufacturing Technology Department,Central Metallurgical R&D Institute,Cairo,Egypt Process and Operational Safety Department,Rashid Petroleum Company,Cairo,Egypt
国际会议
北京
英文
1-8
2013-06-16（万方平台首次上网日期，不代表论文的发表时间）