脱水天然气输送管道腐蚀失效分析

川东油气田天然气集输管道多次出现管道破裂穿孔管事故，利用Ｘ衍射、扫描电镜、电子探针、热重分析等方法对现场的腐蚀挂片和集输管道中收集的腐蚀产物进行了分析检测，结果表明：集输管道虽然经过三甘醇脱水工工艺处理，仍曹受较严重的Ｈ２Ｓ腐蚀，腐蚀形态主要为局部抗蚀，集输管道中形成的腐蚀产物万分 比较复杂，主要为ＦｅＳ，ＦｅＳ２，Ｆｅ３Ｓ４和Ｆｅ９Ｓ８，同时存在一定量的铁的氧化物和其它化合物；管道中腐蚀产物的热

INVESTIGATION OF THE CORROSION OF COLLECTION PIPE OF DEHYDRATED NATURAL GAS TRANSPORT

New processes of dehydration with triglycol are applied in the transport of natural gasin Sichuan-east Datianchi oil/gas field. Accidents of cracking and perforation still occurred in thecollection pipe of natural gas transport. The spot loss-sample and corrosion product collected fromthe pipe were analyzed with X-ray diffraction, electron probe microscopy analysis (EPMA),scanning electron microscope .and thermal analysis. The analysis results show that the collectionpipe of natural gas transport suffered severe hydrogen sulfide corrosion though new processes ofdehydration had been introduced. The pattern of corrosion showed from loss-sample was pittingcorrosion. The components of corrosion product sample from the pipe were relatively complex,which mainly composed of FeS, FeS2, Fe3S4, and Fe9S8, some ferrous oxide composition andsomething else. Thermal analysis of corrosion product sample shows that a strong exothermicreaction exists between 170℃ to 350℃, the enthalpy value(△H) is about -256.8J/g.