Operating air system

The working air system supplies pressed air (0.7 MPa in the example case) for general use throughout the ship.
Also (after reducing the pressure to 0.4 MPa in the example), pressed air is used to destroy the domestic freshwater (FW) hydrophor system and seaweed in Kingston.

Example of a working air system

The working (general service) compressed air system is supplied with air from a working air receiver, which is supplemented with compressed air by a working air compressor. Also, if this compressor could not meet the demand for compressed operating air, then it is possible to supply it from the main compressed air receivers via two 3 / 0.7 MPa reduction valves and a connecting valve from the control air system.
The mixture of compressed air and grease mist from the compressor unit (usually using screw air compressors) is directed to a grease separator where the grease is separated from the compressed air. The separation process has two stages. In the separator, most of the grease is separated by a centrifugal cyclone, and the rest of the grease is separated by grease separation cartridges. The grease separated by the cartridges is returned for circulation to the compressor through a grease return pipe which has an opening through the plate and thus restricts the excess air circulation to the compressor.
Air-free air is supplied from the receiver to the auxiliary cooler. Most of the water is then removed from the cooled air by a water separator. Water is removed from the water separator at regular intervals by opening its solenoid drain valve.
After filling the working air receiver and cooling the compressed air in it, opening the special drainage valves of the receiver removes condensed water vapor and grease residues.
The air supplied from the working air receiver enters the dryer, where it is usually dried by passing it through an activated alumina gel. It is pressed into the lower section of one of the two dryer towers via a three-way shuttle valve. And when the air rises through the activated alumina, moisture and other debris are removed from it. At the same time, a small amount of dried air leaving the first tower expands adiabatically and thus further reduces the relative humidity. This very dry air, moving down the second tower, removes moisture and automatically regenerates the dryer in the reserve tower.