High-purity and high-reliability large-scale air separation unit adopts backflushing self-cleaning filter, Man turbine compressor, air nitrogen water precooling, horizontal radial flow molecular sieve purifier to purify air, liquid oxygen pump compression and expansion Mechanism cold process to obtain low-cost products such as oxygen, nitrogen, and instrument air. The technology of the air separation device is the internationally advanced cryogenic air separation technology: after the air is removed by the molecular sieve, the impurities are cooled, the liquid nitrogen sprayed in the cold box is cooled, the air is liquefied, and the high purity oxygen is obtained by vaporization rectification. Nitrogen and other products. The main production process of air separation plant consists of air compression system, air purification system, air separation system, liquefaction system, high pressure rectification, argon efficiency, liquid storage and transportation system. Raw material air passes through an air filtration system to remove dust and mechanical impurities. The filtered air is compressed by a multi-stage compressor to the pressure required by the process. The compressed air is cooled in sections by direct contact with a post-cooling tower (DCAC), also referred to as an air cooling tower, in convective form by circulating cooling water and cryogenically chilled water. At the bottom of the air cooling tower, the air is pre-cooled by circulating cooling water, and the top air is further cooled by the chilled water.