11293 Effect of H2S/CO2 Corrosion Scale on Hydrogen Permeation

Tuesday, March 15, 2011: 2:15 PM
Room 351 C (George R. Brown Convention Center)
Wenhui Hao1, Lei Zhang*1, Han Li1, Minxu Lu2, and Lining Xu1
(1)University of Science and Technology Beijing; (2)Corrosion and Protection Center, Institute for Advanced Materials and Technology, University of Sciences and Technology Beijing
Hydrogen induced cracking (HIC) of pipeline steel caused by H2S in sour gas field is one of the most important failure forms. Although NACE TM0284 can be used to assess HIC, there is a lack of sufficient knowledge of HIC risk under especially sour conditions such as H2S partial pressure higher than 1MPa. At these conditions, since the electrochemical corrosion under H2S/CO2 coexistence conditions is very serious, the formation of corrosion product scale on the steel surface might significantly affect on the hydrogen permeation and the occurrence of HIC. In order to reveal the mechanisms of this kind of phenomena under high H2S partial pressure, high temperature and pressure corrosion simulation experiments and D-S cell tests are used to analyze the effects of different corrosion product scales on hydrogen permeation under various H2S containing environment condition. The results show that, the scale dominated by Mackinawite promoted the hydrogen permeation behavior, otherwise the scale dominated by Pyrrhotite strongly inhibit hydrogen permeation behavior.