The Working Principle Of Air Separation Units

Air separation equipment-fully known as air separation units (ASUs)-is an industrial facility designed to separate the various gaseous components present in air in order to obtain high-purity gases such as oxygen, nitrogen, and argon. Its operating principle is predicated upon the differences in the physical properties of the constituent gases within the air, achieving gas separation and purification through a series of complex process flows.

 

Core Operating Principle: Cryogenic Distillation
The most widely utilized separation method in air separation equipment is cryogenic distillation. The core of this method lies in exploiting the differences in the boiling points of the various gaseous components found in air to effect separation. At standard atmospheric pressure, the boiling point of oxygen is -183°C, that of nitrogen is -196°C, and that of argon is -186°C. By compressing and cooling air to extremely low temperatures (typically below -180°C) to induce liquefaction, and subsequently subjecting it to multiple cycles of partial evaporation and partial condensation within a distillation column, the equipment leverages these differences in boiling points to achieve the separation of gases such as oxygen, nitrogen, and argon.