Valve fv- opens via trip signal from the plant

As always there is a time limit as the HAZOP is a project deliverable. If you should miss certain hazards or operability issues these will cost you money later in the project as modifications may need to be made to the plant.

Use the HAZOP matrix below provided to help you. Your HAZOP notes will be collected after the exercise, so please record your team number on the HAZOP worksheet.

Description of Tank System

If the ASU trips, valve FV-1 opens via a trip signal from the plant. The valve controls the flow from the vessel to the customer based on a signal from the customer demand.

If a large amount of liquid is rapidly withdrawn from the tank then the pressure can drop. If the pressure is too low in the tank then the liquid will fail to overcome the pressure drop in the downstream systems and we will fail to supply. If the pressure drops, PIC-3 sends a signal to PV-3A which bleeds LOX from the tank to the PBU (Pressure build-up unit). The PBU simply vaporises LOX from the bottom of the storage tank and feeds it back into the vapour space at the top to increase the head pressure in the tank.