About:

• Oxygen is crucial for the treatment of patients with severe COVID-19, since the disease affects lung functioning.
  
  
• One of the ways in which this oxygen can be supplied is through Liquid Medical Oxygen (LMO). LMO is nothing but high purity oxygen used for medical treatment, and is developed for use in the human body.
  
  
• Why in liquid state? Due to its low melting and boiling points, oxygen is in a gaseous state at room temperature. Liquification enables storage in larger volume and easier transportation.
  
  

How Liquid Medical Oxygen is produced?

• There are several methods. The most common production method is separation of oxygen in what are known as Air Separation Units or ASUs.
  
  
• ASUs are basically plants that separate large volumes of gases. They use a method called Fractional Distillation Method to produce pure oxygen from atmospheric air, which consists mostly of nitrogen and oxygen - 78% nitrogen, 21% oxygen and remaining 1% other gases including argon, carbon dioxide, neon, helium, and hydrogen.
  
  
• In this method, gases from the air are separated into various components after cooling them into a liquid state and then liquid oxygen is extracted from it.
  
  
• Atmospheric air is first cooled to -181°C. Oxygen liquifies at this point. Since, the boiling point of Nitrogen is -196°C, it remains in a gaseous state. But Argon has a boiling point similar to that of oxygen (–186°C) and hence a significant amount of Argon liquifies along with Oxygen.
  
  
• The resultant mixture of Oxygen and Argon is drained, decompressed and passed through a second low-pressure distillation vessel for further purification.
  
  
• We then get the output as final purified liquid oxygen, which is then transported using cryogenic containers