For the offshore environment, the closed loop run is not intended to be a performance or load test, but as a mechanism to identify any potential failures. It is also intended to vastly reduce the “clean up” time that is often needed and to eliminate compressor component damage and PCHE (printed circuit heat exchanger) blockage due to corrosion products and foreign debris. It is imperative that the necessary commissioning strainers are in place. Anti-surge valves may be replaced by straight line spools to prevent damage.
Ideally such recycle runs should be carried out at anchorage to ensure a clean supply of seawater cooling is available although it is achievable whilst in the yard with advanced planning (i.e. the use of chiller units). It must be acknowledged that cooling supplies may be limited, and hence temperatures should be closely monitored. This will limit the recycle run duration; however strainer differential pressures may exceed limits first. The run should be planned and engineered in advance, in collaboration with the compressor vendor approval. This should include the test gas composition, suction and discharge pressure and temperature limits.