Technique of Oxygen Generation

Technique of Oxygen Generation, article discusses how successfully oxygen may be created from natural air or raw air utilizing Pressure Swing Adsorpti

This article discusses how successfully oxygen may be created from natural air or raw air utilizing the PSA

(Pressure Swing Adsorption)

or called Technique of Oxygen Generation process . Natural air comprises 21% oxygen, 78% nitrogen, 0.9% argon (inert gas), and 0.1% various traces of gases, as we all know. Our goal is to extract the 21% Oxygen from the remaining gaseous components, primarily the Nitrogen (78%) in Air.

There is three common techniques to generate oxygen

• Cryogenic Separation
• Pressure Swing Adsorption
• Membrane Technology

Pressure swing adsorption (PSA) or Technique of Oxygen Generation is a method that uses external pressure to remove a desired gaseous component (Oxygen) from a mixture of gases or air using a highly selective adsorbent or molecular sieve. The molecular properties and affinity of various gaseous components for the adsorbent material differ. At high pressure, certain adsorbent materials such as activated carbon, zeolites, molecular sieves, and others are used as traps for adsorbing the primary gaseous species (Nitrogen-78%). The entire operation is normally carried out at room temperature. Following this phase, the entire process swings back by providing low pressure in the adsorbing bed to desorb the adsorbed material (Nitrogen) and release it into the atmosphere. As a result, the oxygen concentration produced was 93% or higher.

Pressure-swing adsorption methods function on the idea that gases are attracted to solid surfaces, or "adsorbed under high pressure." As the pressure rises, more and more gases are likely to be absorbed. The gases are desorbed or released when the operating pressure is reduced. PSA techniques are typically used to separate desired gases, such as oxygen in this example, from a mixture of other gases due to their varying degrees of attraction to different solid surfaces.

PSA-based oxygen generating plants typically consist of the following units.

• Compressor
• Air Dryer
• Air Filtration Unit
• Storage Vessel
• Vessels Packed with adsorbing Material
• Oxygen Storage Vessel.

Note: Zeolite is used as an adsorbent, or, say, for trapping Nitrogen Components.

1. In this case, ambient, or natural, air serves as the raw material for the entire process. Air is drawn into the compressor and compressed first.
2. Now Compressed air is passed through an air filter, then a dryer to eliminate any moisture content, before being stored at high pressure in an air storage vessel.
3. This high-pressure air flows through the zeolite bed, where Nitrogen is primarily absorbed in the zeolite pores. After the nitrogen has been adsorbed, the remaining oxygen molecules in the vessel have a concentration of 93% or higher.
4. As the adsorber (zeolite) became saturated with nitrogen gas, it was necessary to regenerate the adsorbing bed in order to maintain oxygen purity.
5. To regenerate the adsorbing bed, a negative pressure is applied to the bed, allowing the trapped nitrogen molecules to be desorbed and ready for adsorption.
6. Because bed regeneration is required following adsorption, two minimum-packed vessels are utilized in industry to make this process continuous. Adsorption is taking place in one vessel, while desorption is taking place in another, swinging back and forth. That is why it is known as the pressure swing technique. A pneumatic and automated vessel balance mechanism guarantees constant oxygen flow.

These plants have a significant capacity to produce oxygen. Because the purity of oxygen is so great, it can also be used for medical purposes. This technology is currently being utilized in hospitals to absorb Nitrogen from the air and generate medical Oxygen for COVID-19 patients. This medical-quality oxygen can be delivered directly to hospitals via pipes. Thus, the oxygen produced is used to fill oxygen cylinders as well as oxygen tankers.

• [accordion]
• 1. PSA Compressed Air drying - Nitrogen Generation
• 
• 2. PSA Nitogen Gas Generators Works
• 
• PSA Technical Analysis