X60管线钢在湿气和溶液介质中的H_2S/CO_2腐蚀行为

H_2S/CO_2 CORROSION BEHAVIOR OF X60 PIPELINE STEEL IN WET GAS AND SOLUTION

利用高温高压反应釜模拟高含硫气田H_2S/CO_2共存环境,分别在流动湿气和溶液介质中进行API-X60腐蚀实验,探讨了高H_2S分压对腐蚀行为的影响.X60管线钢的腐蚀速率在湿气介质中随H_2S分压升高而增加,在溶液介质中则先升高后降低,腐蚀形态均由全面腐蚀趋于局部腐蚀,腐蚀产物以硫铁化合物(Fe_xS_y)为主.H_2S分压为2.0 MPa条件下,溶液介质中形成的腐蚀产物中富S相比例明显增加,HS^-和Cl^-穿过膜层缺陷引发点蚀,多孔且不连续的富S膜层进一步促进点蚀发展.

Wet gas and solution immersion environments containing H2S/CO2 were simulated in a high temperature and high pressure autoclave,respectively.Effects of high H2S partial pressure on corrosion behavior of API-X60 pipeline steel were discussed.The results show that corrosion rate increased with increasing H2S partial pressure in wet gas,while the corrosion rate increased first and then dropped down in solution immersion environment.Corrosion products in both conditions consist dominantly of Fe_xS_y,and general corrosion turned into localized corrosion obviously with H2S partial pressure increasing.The proportion of the sulfur-rich phase in the corrosion products increased prominently in solution immersion condition when the H2S partial pressure up to 2.0 MPa.Pitting of the steel located under the scale＇s defects which act as channels of HS^- and Cl^- ions migrating.The development of pitting could be accelerated by the discrete and porous sulfur-rich corrosion products.