The vapor from the process skid sometimes carries liquid particles which can harm the compressor need to be separated from entering into the compressor. The common Suction Accumulator known as “Knock-Off Drum” installed before the ammonia compressor helps to ensure liquid refrigerant is separated before the vapor enters the compressor. The heavier liquid particles are accumulated in the Suction Accumulator and evaporated by the automation controls provided for the circulation of hot gas from the discharge of the Ammonia Compressor to the condenser through the Suction Accumulator.

The Suction Accumulator shall be a vertical vessel sized for the designed refrigeration capacity of the compressor package with a stand pipe on which level switches shall be mounted at different heights as required by the process. Coils shall be provided inside the vessel for the circulation of hot ammonia gas to evaporate the liquid accumulated. The suction accumulator shall also be complete with Demister pad just before the top dish installed to stop liquid molecules if any and allow only ammonia vapor only to pass through and sight glasses for periodic inspection.