CO_(2)环境中管内外温差对X65湿气管线顶部腐蚀的影响  

Effect of temperature difference inside and outside the pipe on top corrosion of X65 wet gas pipeline in CO_(2) environment

作　　者：封子艳 崔铭伟 高志亮 FENG Zi-yan;CUI Ming-wei;GAO Zhi-liang(Chemical and Safety College,Binzhou College,Binzhou 256600,Shandong,China;Research Institute of Shaanxi Yanchang Petroleum Co.,Ltd.,Xi’an 710065,Shaanxi,China)

机构地区：[1]滨州学院化工与安全学院,山东滨州256600 [2]陕西延长石油(集团)有限责任公司研究院,陕西西安710065

出　　处：《天然气化工—C1化学与化工》2021年第5期74-80,共7页Natural Gas Chemical Industry

基　　金：国家自然基金(51801013)。

摘　　要：为理清延长气田CO_(2)含量(体积分数)、管内介质与管壁温差对X65湿气管线顶部腐蚀的影响,提高延长气田顶部腐蚀防护能力,应用自制管式冷凝和顶部腐蚀模拟实验装置,采用挂片失重法、扫描电镜以及EDS能谱等分析手段,分析了不同CO_(2)含量、腐蚀温度条件下,管线顶部冷凝速率、顶部冷凝液pH值、挂片均匀腐蚀速率、挂片表面形貌、挂片截面形貌变化情况及腐蚀产物能谱特点。结果表明:管内介质与管壁温差增加,管段顶部冷凝速率呈指数升高,顶部冷凝液pH值略微升高,挂片表面腐蚀由局部腐蚀向均匀腐蚀转变,管线顶部冷凝速率严重影响挂片腐蚀形貌;CO_(2)含量增加,冷凝液pH值降低,挂片表面均匀腐蚀、局部腐蚀速率均增加,但对均匀腐蚀与局部腐蚀之间的转化影响不大;顶部外层腐蚀产物膜质地疏松,内部存在明显裂痕,易在挂片表面形成局部腐蚀,内层腐蚀产物膜腐蚀初期未能形成有效防护,导致局部腐蚀严重;CO_(2)含量不同时,腐蚀产物主要成分Fe、O元素变化不大,腐蚀产物为FeCO_(3)。In order to clarify the influence of CO_(2) content(volume fraction)and temperature difference between tube wall and medium in tube on the top corrosion of X65 in wet gas pipeline,and to improve the corrosion protection ability of the top corrosion of Yanchang gas field,a self-made tube condensation and top corrosion simulation experimental device was set up.By means of hanging weight loss method,scanning electron microscope and EDS energy spectrum,condensation rate at the top of pipeline,pH value of top condensate,corrosion rate of hanging pieces,surface morphology of hanging pieces,cross-section morphology of hanging pieces and corrosion product energy spectrum characteristics under different CO_(2) contents and corrosion temperatures were analyzed.The results show that,with the temperature difference between the medium and the wall of the pipe increasing,the condensation rate at the top of the pipeline increases exponentially,pH value of top condensate slightly increases,and corrosion on the surface of the hanging pieces changes from local corrosion to uniform corrosion,condensation rate at the top of the pipeline seriously affects the corrosion morphology of the hanging pieces.With the increase of CO_(2) content,pH value of the condensate decreases,and the rates of uniform corrosion and local corrosion on the surface of hanging pieces increase,but it has little effect on the transformation between uniform corrosion and local corrosion.The outer corrosion product film of the top corrosion has loose texture and obvious cracks inside,which is easy to form local corrosion on surface.The inner corrosion product film fails to form effective protection at the initial stage of corrosion,resulting in serious local corrosion.When the CO_(2) content is different,the main components Fe and O of the corrosion product change slightly,and the corrosion product is FeCO_(3).

关 键 词：X65管线钢 顶部腐蚀 CO2含量 腐蚀温度 腐蚀产物膜 局部腐蚀 

分 类 号：TE832[石油与天然气工程—油气储运工程]