摘要
为解决某乙烷外输管道阴极保护投产试运行(以下简称投运)过程中管道中段3#阀室两侧约20 km保护电位不达标的异常问题,对设备调试参数有误、阴极保护站及阳极地床设置不合理、杂散电流干扰、防腐层质量差、保护电流异常漏电等主要影响因素进行了分析研究。研究初步判定保护电位不达标是由保护电流异常漏电所致;分析绝缘接头漏电、穿越套管搭接、阀室漏电等保护电流异常漏电的主要原因,判定管道保护电流异常漏电原因为阀室异常漏电;计算阀室主工艺区和放空区接地极表面积和电流漏泄量等参数,推断异常漏电部位为放空区;对放空区管道和接地极异常漏电部位排查,查明地面管道保温外护层的自攻螺栓穿透防腐层与管道本体异常接触导致漏电;最后按相关标准规范进行整改,管道保护电位达标。研究成果对阴极保护投运异常处置提出了系统全面分析和排查问题的思路与方法,为今后类似异常问题的处置提供了参考和建议。
During cathodic protection commissioning and trial operation,the protection potential of about 20 km on both sides of the 3#valve chamber in the middle section of an ethane export transmission pipeline did not meet performance standard.In order to solve the abnormal phenomenon,the main influencing factors such as incorrect equipment debugging parameters,non-optimal setting of cathodic protection station and anode ground bed,stray current interference,poor quality of corrosion protection layer and abnormal leakage of protection current were analyzed and studied.It is preliminarily determined that the substandard protection potential is caused by abnormal leakage of current.The main causes of abnormal leakage of protection current,such as insulation joint failure or leakage,crossing casing lap,valve chamber leakage,etc.,were analyzed.The abnormal leakage of valve chamber is identified.The surface area and current leakage of the ground electrode of the valve chamber in the main process area and the flare area are calculated,and the abnormal leakage is inferred to be the flare area.Checking the abnormal leakage parts of the pipeline and the grounding pole in the vent area,it is found that the self-tapping bolt of the insulation outer protection layer of the ground pipeline penetrates the corrosion protection layer and make contacts with the pipeline body,resulting in current leakage.Finally,rectification was carried out according to relevant standards and specifications,and the pipeline protection potential reached the standard requirement.The research results put forward systematic and comprehensive analysis and troubleshooting ideas and methods for the resolution of abnormal cathodic protection problems,and provide reference and suggestions for similar abnormal cathodic protection commissioning and trial operation in the future.
作者
马含悦
张平
黄春蓉
屠海波
牟华
李天雷
关越
施岱艳
李浩
邹绍维
刘海禄
上官昌淮
MA Hanyue;ZHANG Ping;HUANG Chunrong;TU Haibo;MU Hua;LI Tianlei;GUAN Yue;SHI Daiyan;LI Hao;ZOU Shaowei;LIU Hailu;SHANGGUAN Changhuai(CPECC Southwest Company,Chengdu,Sichuan,610041,China;PipeChina South China Branch,Maoming,Guangdong,525000,China)
出处
《天然气与石油》
2023年第6期122-128,共7页
Natural Gas and Oil
基金
中国石油工程建设有限公司重点工程“塔里木油田天然气乙烷回收工程”(S2017112E)。
关键词
乙烷外输管道
阴极保护
阀室
漏电
保护电位
Ethane external pipeline
Cathodic protection
Valve chamber
Current leakage
Protection potential
