Compression:

In this stage, atmospheric air is drawn into the ASU and passed through a series of compressors to increase its pressure. The purpose is to make the subsequent cooling and separation processes more efficient, and typical pressures range between 5 and 10 barg.

Purification:

Before further processing, the compressed air is usually purified to remove impurities (including moisture, carbon dioxide or trace contaminants). This step ensures that the separated gas is of high purity and avoids problems such as freezing or clogging of cryogenic equipment.

Cooling:

The now purified compressed air is cooled to cryogenic temperatures using a series of heat exchangers and refrigeration cycles. This causes the air to liquefy, as cryogenic distillation relies on differences in the boiling points of the various components.

Separation:

The now cold liquefied air is fed into a distillation column (or series of distillation columns) so that the air is separated into its main components based on differences in boiling points.

Collection, storage and delivery:

The separated gas is collected and sent to storage tanks, which can be pressurized tanks or cryogenic tanks. The gas can then be distributed and supplied to a variety of industries and applications, depending on the purity requirements.