Full liquid air separation process

The purified air enters the fractionator and exchanges heat with the returned polluted nitrogen, oxygen and nitrogen through the main heat exchanger. After cooling, a small part of it is liquefied, and the gas-liquid mixed air is throttled to the pressure of 0.55 MPa. After distillation, 99.999% pure nitrogen is obtained at the top of the lower column, and then it enters the main cooling column, and is condensed into liquid nitrogen by evaporation of liquid oxygen in the upper column. A part of liquid nitrogen is returned to the lower column as reflux liquid, and the remaining liquid nitrogen is throttled after cooling. Enter the sprayer at the top of the upper column. The bottom residue is liquid air containing 38% oxygen. After passing through the liquid air subcooler, it enters the middle of the upper column to participate in distillation. At the same time, the polluted liquid nitrogen flow is drawn out from the middle of the lower column and then enters the upper column as reflux l

In the air separation unit, the function of air cooling column is to reduce the temperature of air compressed by air compressor. Air cooling column is a kind of hybrid heat exchange equipment. In order to increase the heat transfer area, make the cooling water fully contact with the air and mix completely to enhance the heat transfer effect, the air cooling column usually adopts several structural forms such as packed column, sieve plate column or hollow spray column.