Air Separation Unit (ASU)

Product Brief Introduction

Air separation units (ASU) use air as raw material and convert it into liquid through processes such as compression, circulation, and deep cooling. They then use distillation towers to gradually separate gases or liquids such as oxygen, nitrogen, and argon from the liquid air.

System flow

An air separation unit (ASU) primarily consists of an air filtration system, an air compression system, an air pre-cooling system, a molecular sieve purification system, a fractionating tower system, an expander, an instrumentation and control system, an electronic control system, and a liquid storage and vaporization system. The main process flow is as follows: After being filtered to remove dust and other mechanical impurities, the raw air enters the air compressor. It is then compressed to the required pressure by an intercooler for inter-stage cooling. The air is then sent to the pre-cooling system and cooled to -10°C. The air from the pre-cooling system enters the molecular sieve adsorber. The two adsorbers are used alternately, with one operating while the other is regenerated with contaminated nitrogen. The cooled, saturated air enters the purification system, where impurities such as moisture, CO₂, and C₂H₂ are removed from the molecular sieve adsorber, resulting in clean, dry air. The purified air then enters the distillation tower system, where oxygen, nitrogen, and argon are distilled out. The distilled liquid oxygen, nitrogen, and argon are then sent to the storage system.