High nitrogen use was being observed on plant. Many of the storage tanks had nitrogen blanketing in the vapour space to control pollution while protecting against damage caused by pulling a vacuum. Some of the tanks had pressure relief valves that relieved to vapour recovery systems, others vented to atmosphere, depending on what type of chemical was stored within.
CVS was called to site to help plant operators determine if the pressure relief devices were causing nitrogen loss. After a Tank Walk-Around the CVS engineers observed issues with the Pressure Relief Devices and worn seals and Tank Blanketing Regulators were stuck in the open position.
Immediate action was taken to resolve the leaks from the Pressure Relief Devices, leaking seats were re-conditioned and seals replaced. The next focal point was the Tank Blanketing Devices. These were removed, cleaned and o-ring seals replaced.
The initial action that was taken resolved the issue of high nitrogen use, Pressure Relief Devices now sealed correctly, and Tank Blanketing Devices opened and closed when required. Moving forward a maintenance program was introduced, and all tank top equipment is to be inspected by CVS on a yearly basis and every two years the equipment is removed and tested.