For getting pure gases from the atmospheric air we use cryogenic distillation technology in the plant machinery. In order to obtain pure oxygen, we use cryogenic oxygen plant which taps the oxygen from atmosphere that is then cooled until it gets liquefied. Afterwards, oxygen is distilled at its boiling point, that is, -183 degree Celsius. Using this process high purity gases such as oxygen, nitrogen and argon can be generated. The process was discovered in 1930s by Carl Von Linde and is still being widely used across the globe for producing high purity gases.
For smooth functioning of cryogenic oxygen plant there should be close integration of heat exchangers and air separation columns for ensuring efficiency. And, the energy for refrigeration is delivered by compression of the air. For achieving low distillation temperatures it needs a refrigeration cycle and coldmust be placed within an insulated enclosure which is commonly called as cold box. For cooling gases to cryogenic temperatures a lot of energy is required which is provided by air compressor. Modern cryogenic air separation plants use expansion turbines for getting energy for running refrigeration cycle.
After the air is compressed, it is passed through a molecular sieve where vapor, carbon dioxide and hydrocarbons are removed. Next the air is passed through heat exchangers where it gets cooled to extreme low temperatures. Then, the process air is passed into high pressure distillation column where vaporous oxygen is formed at the top of the column and nitrogen is formed at the bottom of the column.
Applications of cryogenic oxygen plant
- Chemical and petrochemical industries
- Fish farming
- Glass industry
- Metal gas welding, cutting and brazing
- Metal industry
- Oil and gas industry