Each cylinder discharge line should have a relief valve located upstream of the cooler. Like all reciprocating devices, the piston will continue to increase pressure if flow is blocked. The relief valve assures that nothing is overpressured. It must be located upstream of the coolers as ice can form in the coolers, blocking flow.
Pulsation Bottles
Each cylinder should have suction and discharge pulsation bottles to dampen the acoustical vibrations caused by the reciprocating flow.
Discharge Coolers
These cool the interstage gas. They may also be required to cool the discharge gas prior to gas treating or dehydration or to meet pipeline specifications. Typically, aerial coolers are used in these situations.
Suction Scrubbers
Suction scrubbers are required on the unit suction to catch any liquid carry-overs from the upstream equipment and any condensation caused by cooling in the lines leading to the compressor. They are also required on all the other stages to remove any condensation after cooling. On each suction scrubber a high level shut-down is required so that if any liquids do accumulate in the suction scrubber, the compressor will automatically shut down before liquids carry-over to the compressor cylinders.
