From analyzing the literature on this subject and based on our own experience, we differentiate all hydrogen damage failures into two main groups based on two mechanisms: electrochemical processes (mainly at low temperature, up to ~100oC) arising from acid corrosion or cathodic protection, and high temperature (between 200 and 500oC) arising from the presence of hydrogen gas at high pressures.
Examples of hydrogen damage are given for the various units of oil refineries. Different monitoring methods were developed for detection of possible hydrogen damage. Hydrogen can be detected either in intrusive or non-intrusive devices called hydrogen probes. Hydrogen that penetrates through a metallic wall can be detected with manometric (hydrogen pressure) or vacuum method, electrolytically (hydrogen ionization from H atoms into H+ ions), heat conduction (gas chromatography), vacuum extraction at 400oC, or hydrogen effusion. Monitoring methods are critically reviewed.
Preventive measures of hydrogen failures are differentiated into two groups according to low and high temperature mechanisms. The first group includes protective measures from hydrogen blistering and sulfide stress cracking: metallurgical measures, change of environmental conditions (removing aggressive species such as sulfides, cyanides, and arsenic compounds, neutralization, injection of inhibitors of hydrogen penetration), use of organic, inorganic and metallic coatings, heat treatment and proper welding. The second group includes metallurgical measures (use of steels containing chromium and molybdenum and decrease of carbon content in the steel), heat treatment and proper welding. Analysis of preventive measures of hydrogen failures was carried out and recommendations were given.
Keywords: hydrogen damage, oil refining industry, monitoring, prevention.