Operation and maintenance of air separation unit

The oxygen and nitrogen products produced by the air separation unit in the external compression process are low-pressure oxygen and nitrogen from the upper column, which are sent out of the cold box after being reheated by the heat exchanger. The product gas pressure out of the cold box is generally 0.12MPa. After being compressed to the pressure required by the user by the oxygen compressor, it is sent to the user’s pipeline. The internal compression process of oxygen is that liquid oxygen products are directly extracted from the condensing evaporator, compressed to the user's required pressure by the liquid oxygen pump in the cold box, and then sent to the user's pipeline after reheating and gasification by the heat exchanger.

In the air separation plant, the main heat exchanger is the key equipment to ensure the performance of the whole set of equipment. The function of the main heat exchanger in the molecular sieve pre purification process air separation equipment is to ensure the temperature difference at the hot end to be kept at the design value by recovering the cold quantity of the backflow gas, provide sufficient expander gas to expander, make up for the cold quantity loss of the equipment, and provide the raw gas under the design condition for the lower tower.