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Title: Electrochemical hydrogen permeation studies of several mono- and diamines

Journal Article · · Journal of the Electrochemical Society
DOI:https://doi.org/10.1149/1.2048657· OSTI ID:122707
;  [1];  [2]
  1. Saudi Aramco, Dhahran (Saudi Arabia). Lab. Research and Development Center
  2. King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia). Dept. of Chemistry

The combined presence of moisture and hydrogen sulfide, known in the oil industry as a sour environment, enhances corrosion reactions at a metal surface as well as promotes the entry of hydrogen atoms, resulting from these reactions, into the metal. Increased entry of hydrogen atoms increases the probability of occurrence of hydrogen-induced cracking. The objective of this study is to evaluate the ability of several organic amines to inhibit the overall process of hydrogen entry and to relate their inhibition abilities to their molecular structures. The diffusion coefficients for the permeation of hydrogen atoms through steel estimated in this study using the time-lag and Laplace methods are of the same order of magnitude as those in the published literature. In several hydrogen permeation curves, a characteristic hump was observed. The authors propose that this hump is due to the trapping of hydrogen at sites other than voids and microvoids. The electrochemical system was also sued to study the effectiveness of diethanolamine (DEA), morpholine (MOR), triethanolamine (TEA), ethylenediamine (EDA), and hexamethylene diamine (HMDA) in inhibiting the entry of hydrogen atoms into steel. The diamines were found to be more effective than the monoamines. A nonlinear relationship was observed between the inhibition effectiveness and the concentration of the amines studied. The inhibiting abilities of the monoamines were similar at the high concentration limit (0.01 M) but followed the trend TEA > MOR > DEA at the low concentration limit (5 {times} 10{sup {minus}5} M). For the diamines the inhibiting abilities were also similar at the high concentration limit (5 {times} 10{sup {minus}3} M) and followed the trend HMDA > EDA at the low concentration limit (5 {times} 10{sup {minus}5} M).

Sponsoring Organization:
USDOE
OSTI ID:
122707
Journal Information:
Journal of the Electrochemical Society, Vol. 142, Issue 9; Other Information: PBD: Sep 1995
Country of Publication:
United States
Language:
English