The level of hydrogen sulphide in gas supplies to four plants operated by Abu Dhabi Gas Industries (GASCO) was increasing. In most parts of the plants, the hydrogen sulphide levels had exceeded the limit for which the equipment had been designed. Intetech evaluated each equipment item, including static and rotating equipment, piping, valves and instrumentation, to define the extent to which the equipment could continue operation without risk of failure.

We recommended that GASCO should perform specific environmental monitoring of the gas composition and condensed water chloride content. This would give the company warning of potentially dangerous conditions, so that action could be taken to prevent catastrophic failure and safe operation could be guaranteed. We defined the limits within which GASCO could confidently continue to operate all four gas plants without expensive reconditioning.

Abu Dhabi Marine Operating company asked us to review a pipeline that would be carrying hydrogen-sulphide-containing gas but that had not been built for sour-service conditions. We examined the original steel supply documents and welding procedures so that the risks of sulphide-stress and hydrogen-steel cracking could be assessed. Operating experience and inspection data were also taken into account.

We identified the risks and estimated the types and extent of damage that might arise. This enabled the company to continue operation of the pipeline beyond its original design life and outside the original design conditions, but within a guiding set of limiting conditions. The company realised a substantial saving, as a replacement line was not required.