A South American operator developed plans to return a sulfur recovery unit to service after an initial ten years of service and a further ten years of mothballing due to changes in field production requirements.

The corrosive nature of molten sulfur, carbon dioxide and hydrogen sulfide in the unit, coupled with the expectation of a less than optimum preservation strategy in a littoral offshore environment, generated a large set of integrity risks that needed to be evaluated to determine the feasibility of repairing and reinstating the system for a further ten years of service.