Abstract
Explosions, fires, plant shutdowns, injuries and destruction, the majority of these failures are corrosion related. More specifically, for refining, petrochemical, marine environments and power plants, industries with vast amounts of piping, the cause of production delay is due to corrosion damage under insulation that make it very hard to inspect and detect damages prior to failures. For corrosion under insulation, there are further complications from having to inspect the structures to ascertain the existence and extent of corrosion. Maintenance and plant inspection become labor and time intensive when large quantities of insulation have to be removed. Despite advances in materials and inspection technologies, CUI remains a serious and costly industry problem. In this investigation four API 5L X65 steel pipes were insulated with thick foam to determine the effective protection of a commercially available vapor phase corrosion inhibitor (VCI) against CUI. Electrochemical potential and corrosion rate were monitored under isothermal and cyclic wet/dry test conditions. Test results have demonstrated that VCI can successfully reduce corrosion attack under insulation even in a chronic wet environment. When VCI was used, the corrosion rate was reduced by a factor of 30. These results showed that an effective protective coating system under the insulation is critical and requires the inclusion of VCI to prolong the pipe integrity and lower inspection and maintenance cost.
