Electrochemical Studies of Hydrogen Permeation in Petroleum Production and Process Environments
Authors: Pawloski John N. , Leary Michael J. , Deegan Dennis C. 
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.
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Abstract
A procedure for the quantitative measurement of hydrogen flux through metal membranes is described Environments similar to those found in petroleum production and process operations were used for hydrogen process operations were used for hydrogen generation. Application of this technique is directed to both the performance evaluation of various inhibitor formulations and elucidation of the mechanism of inhibition.

Introduction
The problem of hydrogen penetration into materials utilized in petroleum production antiprocess operations has plagued production antiprocess operations has plagued this industry for a significant number of years. Damage is normally characterized by blistering or embrittlement depending on the strength level of the particular steel in question. Hydrogen activity in systems susceptible to such attack is normally monitored in plant by pressure sensing probes described by Bonner et al. Protection is generally attained by Protection is generally attained by metallurgical design consideration, control of system chemical parameters or addition of inhibitor formulations. This study is concerned primarily with the last method mentioned and is directed to the design of laboratory test procedures for evaluating permeation inhibitors under various permeation inhibitors under various simulated operational environments.

Background
Metallurgy susceptible to damage by hydrogen penetration can be found in both modern day crude oil production and refining operations. Chemical environments necessary for promotion of this phenomenon are common in such processes as hydrodesulfurization and petroleum production from hydrogen sulfide bearing formations. Material failure is normally evidenced by blistering or embrittlement, in steel above Rockwell C-22 hardness. Chemical parameters monitored in addition to sulfide are parameters monitored in addition to sulfide are ammonia and cyanide. Together these three species can comprise the most hostile of permeation environments. permeation environments. If one considers the corrosion of iron by hydrogen sulfide alone, a protective film of iron sulfide, FeS, is usually formed causing the corrosion reaction to abate after a short period. The presence of cyanide, however, at levels of several hundred parts per million facilitate removal of this per million facilitate removal of this protective film by formation of a soluble protective film by formation of a soluble ferrocyanide complex, Fe(CN)6-4.