What is the Air Separation Unit?

An Air Separation Unit (ASU) is a system that separates atmospheric air into its primary components, typically nitrogen and oxygen, and sometimes also argon and other rare inert gases. The most common method for air separation is fractional distillation.

Here's a brief overview of how an ASU works:

1. Air Compression: The atmospheric air is compressed, typically to pressures between 5 and 10 bar gauge.
2. Pre-filtration: The compressed air is pre-filtered of dust.
3. Moisture and CO2 Removal: The air is passed through a molecular sieve bed, which removes any remaining water vapour and carbon dioxide.
4. Cryogenic Distillation: The clean, dry air is then cooled until it liquefies, and the components are selectively distilled at their various boiling temperatures.

This process can produce high purity gases but is energy-intensive. The cryogenic separation process requires a very tight integration of heat exchangers and separation columns to obtain a good efficiency. All the energy for refrigeration is provided by the compression of the air at the inlet of the unit. Modern ASUs use expansion turbines for cooling; the output of the expander helps drive the air compressor, for improved efficiency.

CenturyVal is one of the most experienced manufacturers of air separation units in China. CenturyVal provides cryogenic valves for air separation, air compression, molecular sieve adsorption, and air distillation (cold box). We also provide corresponding transportation and technical services.

The cases show 400Y cryogenic valves, 500/600/800/1000/1300/1500 high pressure nitrogen control valve on the cold box, and anti-surge valve on the compressor.