1. Air separation equipment process freezing method removes moisture and CO2. In the cooling process, water and CO2 are separated and frozen in the heat exchanger channel. After a certain time, the channel can be switched, and the impurities will be taken away by the return of the polluted nitrogen gas. According to the type of heat exchanger, it is divided into the storage cooler and the plate - fin type heat exchanger. In this way, the switching action is frequent, the start-up operation is more complex, the technical requirements are high, and the operation period is about 1 year.
2. The process of air separation equipment is adsorbed and purified by molecular sieve. Before entering the main heat exchanger, the air is cleaned by the absorber. Adsorber switching cycle is long, the operation is greatly simplified, pure nitrogen product quantity is no longer restricted by reflux volume requirements, cycle can be up to two years or more than two years, more and more widely used.