Liquid oxygen (LOX) is manufactured by liquefaction and separation of air from nitrogen, argon & other gases. It is pale blue in color & has a freezing point of (−182.96 °C) and boiling point of (−182.96 °C at 101.325 kPa. Due to its expansion ratio of 1:861 under 1 standard atmosphere (100 kPa) and 20 °C, it is economical to transport and store. It is used in numerous industrial, military and space applications. However, it must be noted that oxygen is primarily used in its gaseous state so why LOX is produced on such a scale. This is because of the reason that transporting LOX is easy. And, storage of Liquid oxygen is preferred because of it is economical.
Now, you might wonder how liquid oxygen storage is cost-effective as compared to gaseous storage. Well, it is simple there are significantly lower leakage of oxygen from cryogenic oxygen storage. If there is low leakage it is saving you money and so is obviously economical. Liquid oxygen is produced via a cryogenic oxygen plant which is manufactured using cryogenic distillation technology. Only high quality materials are used in the fabricating of cryogenic storage tanks. It is ensured that that materials used are able to withstand extreme temperature and pressure.
Liquid oxygen is generated by taking air from atmosphere into the air separation unit. After being let into the oxygen plant, the air is compressed. Then, it is directed into the cleanup system where impurities such as hydrocarbons, carbon dioxide and moisture are removed. After the process air is cleaned, it is passed through heat exchangers where it is cooled to extreme cryogenic temperatures. Then, the air is moved into high pressure distillation column where oxygen is physically separated from nitrogen and other gases. Want to know that How Liquid Oxygen is Made? Liquid oxygen is formed at the top of the column and is now moved into low pressure distillation column where oxygen is further distilled for getting desired level of purity.