The operator of a large offshore LNG re-gasification terminal was searching for an alternative to a major plant shutdown, this to enable replacement of a pipe section and associated equipment on its facility.
As there were no suitable isolation points as per the facility design, it was decided to utilise the AOGV mechanical isolation tool to minimise the isolation impact. Two 3” class 150 cryogenic rated AOGVs were installed upstream on a knockout drum nozzle, as well as downstream on the drain line. The AOGV isolated on both sides of the pipe section by installing an isolation spade as a blind flange on each side of the spool, enabling a complete replacement of the pipe section without any downtime.
In addition to avoiding to shut down and restart the process plant, savings were realised in decreased HSSE exposure, less planning time and time spent in plant by minimising the area impacted by the isolation.
The AOGV is CE-marked, and was tested with liquid nitrogen as test medium to simulate site conditions. The AOGV was sealing at test temperatures as low as – 170 degrees Celsius.