Corrosion Under Insulation Examination to Prevent Failures in Equipment at a Petrochemical Plant

An examination of the corrosion under insulation phenomenon in insulated equipment at a petrochemical plant with the purpose of preventing corrosion-attributed failures was carried out. The study was performed after a risk-based inspection analysis identified the equipment with higher risks of developing corrosion under insulation. Visual inspections of several accessories located at several positions of the current process unit’s pipelines, heat exchangers, filters and pressure vessels were performed after the insulation was removed. Among the main findings, most accessories (nozzles, insulation support rings) located at the top of the equipment showed moderate corrosion. Additionally, there were differences in the results depending on the insulation material (mineral wool, foam glass or calcium silicate) covering the equipment/accessories. This work showed how adequate and timely monitoring and management of corrosion can successfully prevent costly and frequent failures associated with corrosion under insulation.