含CO_(2)湿天然气长输管道内腐蚀原因及其防控措施  

Internal Corrosion Causes of a CO_(2)-Containing Wet Natural Gas Long-Transmission Pipeline and Its Prevention Measures

作　　者：薛吉明 戴联双 张安妮 王修云 XUE Jiming;DAI Lianshuang;ZHANG Anni;WANG Xiuyun(National Oil and Gas Pipeline Network Group Co.,Ltd.,Beijing 100013,China;Natural Gas Treatment Plant of Zhongyuan Oilfield Branch of Sinopec,Puyang 457162,China;Safetech Research Institude(Beijing)Co.,Ltd.,Beijing 102209,China)

机构地区：[1]国家石油天然气管网集团有限公司,北京100013 [2]中国石油化工股份有限公司中原油田分公司天然气处理厂,濮阳457162 [3]安科工程技术研究院(北京)有限公司,北京102209

出　　处：《腐蚀与防护》2023年第9期113-117,共5页Corrosion & Protection

摘　　要：针对某含CO_(2)湿天然气长输管道的内腐蚀问题,通过管道运行工况调研、腐蚀形貌观察及腐蚀产物成分分析,明确了该管道的内腐蚀原因,并提出了该类天然气管道的内腐蚀防控措施。结果表明:由于管道的天然气露点控制不严格,在环境气温较低而输送气体温度相对较高时,管道内壁可能出现冷凝水液膜或液滴,冷凝水沉降造成某些低洼位置的管段出现积水,CO_(2)溶于液态水形成较强腐蚀性的碳酸,从而发生CO_(2)腐蚀;同时,在管道水压试验过程中,未对试压水进行除氧和杀菌处理,在水压试验结束后,又未及时清理和干燥管道,会导致管道在投产前就存在积水,从而造成溶解氧腐蚀和细菌腐蚀。Aiming at the internal corrosion problem of a CO_(2)-containing wet natural gas long-transmission pipeline,the internal corrosion causes of the pipeline were clarified by investigating the pipeline operation conditions,observing the corrosion morphology and analyzing the composition of corrosion products,and the internal corrosion prevention and control measures of this type of natural gas pipeline were proposed.The results showed that due to the lack of strict control of the natural gas dew point of the pipeline,when the ambient temperature was low and the temperature of the transported gas was relatively high,the condensate liquid film or droplets might appear on the inner wall of the pipeline.The settlement of the condensate water caused water accumulation in some low-lying sections of the pipeline,and CO_(2) dissolved in the liquid water to form a strong corrosive carbonic acid,resulting in CO_(2) corrosion.At the same time,in the process of pipeline hydraulic test,the test water was not deoxygenated and sterilized.After the end of the hydraulic test,the pipeline was not cleaned and dried in time,which would lead to water accumulation before the pipeline was put into operation,resulting in dissolved oxygen corrosion and bacterial corrosion.

关 键 词：湿天然气 长输管道 CO_(2)腐蚀 防控措施 

分 类 号：TG174[金属学及工艺—金属表面处理]