Contribution of CO_2 on hydrogen evolution and hydrogen permeation in low alloy steels exposed to H2S environment

摘要

Hydrogen charging in low alloy steels is a major problem in oil and gas environments containing hydrogen sulfide (H_2S). The risk of sulfide stress cracking (SSC) is usually determined from the values of water pH and H_2S partial pressure (P_(H2S)). The goal of the present study is to check if hydrogen charging is influenced by other parameters than the sole pH and P_(H2S), and especially by carbon dioxide (CO_2). Experiments engaged the measurement of hydrogen permeation through thin mild steel membranes under potentiometric control. Charging solutions with different H_2S concentrations with or without CO_2 were used, in order to examine their individual contributions to the charging flux.