An oxygen generator, commonly known as a PSA oxygen plant, is used for separating oxygen gas from atmospheric air under various pressure and temperature conditions.
Working Principle of PSA Oxygen Generator
The PSA Oxygen Generator operates on the principle of adsorption, a surface phenomenon where nitrogen molecules from air adhere to the surface of an adsorbent material (in this case, zeolite molecular sieves).
Here’s how it works:
- Atmospheric air is compressed and passed into the PSA bed, a pressure vessel packed with zeolite molecular sieves and activated alumina.
- The nitrogen molecules are adsorbed by the zeolite.
- The oxygen molecules pass through and are collected in an oxygen storage tank.
This cycle is fully automated and managed by a PLC (Programmable Logic Controller) and valves.
Components of a PSA Oxygen Generation System
An Oxygen generation system comprises several critical components:
- Air Compressor
- Compresses atmospheric air to a pressure of 5-7 barg.
- Screw compressors are preferred due to their high efficiency, low noise, and compact size.
- Air Dryer
- A refrigerated dryer cools compressed air to separate the moisture from compressed air coming from the air compressor
- The refrigerant gas cools this, and the moisture is separated with the help of a drain.
- Air Receiver / Tank
- Dry compressed air is stored in an air receiver. The air receiver provides the necessary buffer to accommodate fluctuating air demands, enabling the compressor to operate efficiently.
- Air Line Filters
- Removes oil, dust particulates, and any residual moisture from compressed air.
- Line filtration is extremely critical, as any traces of oil and moisture are detrimental to Zeolite molecular sieves (adsorbent)
- PSA Oxygen Generator (with PSA Bed or Adsorber)
- The dry and purified compressed air from the air receiver is passed through the PSA towers.
- A PSA tower can be described as a pressure vessel filled with zeolite molecular sieves and activated alumina, where compressed air is fed as an input and oxygen is produced via adsorption by adsorbing the Nitrogen molecules and allowing the oxygen molecules to pass through.
- This process of oxygen production is fully automated and is performed with the help of valves and a PLC.
- Oxygen Storage Tank
- Oxygen gas generated through the PSA generator is stored in a storage tank for further supply to the point of use through pipelines.
A storage tank ensures a continuous supply of oxygen and takes care of variable demands as per application requirements.
Applications of PSA Oxygen Generator
Some common applications of oxygen produced from the PSA oxygen plant are listed below :
- Medical oxygen production in hospitals, nursing homes and medical colleges.
- Brazing & Welding operations
- Wastewater treatment
- Oxygenation
- Metal cutting in Steel plants
- Glass manufacturing
- Paper production
- Ozone generation
Different Sources of Oxygen in Industry
Industries can source oxygen in three primary ways:
- High-Pressure Oxygen Cylinders
- Liquid Oxygen Tanks (LOX)
- PSA Oxygen Generators (On-site)
Comparative Analysis of Oxygen Sources
| # | Parameters | Liquid Oxygen | High-Pressure Cylinders | PSA Oxygen Generator |
| 1 | Oxygen Cost per Nm³ | High | Very High | Low |
| 2 | Safety Risk | High (Due to the high expansion ratio of liquid Oxygen to gas) | Very High (Due to High pressure of 150 Barg in the cylinders) | Low (Due to low pressure of 5.5 Bar ) |
| 3 | 3rd Party Dependence | Yes (Regular Refilling required) | Yes (Regular Refilling required) | No (On-site generation) |
| 4 | Carbon Emissions | High (Due to the logistics involved) | High (Due to the logistics involved) | Very Low (On-site generation) |
Please read the detailed description and comparison of different sources of oxygen is explained in our blog titled Selecting the Right Oxygen Delivery System for Your Hospital
Cost Comparison of Different Oxygen Sources
| Source | Cost (₹/Nm³) |
| Liquid Oxygen | ₹15 – ₹25 (Cost depends on the distance from the Liquid Oxygen production plant to the industry) |
| High-Pressure Cylinders | ₹30 – ₹60 (Cost of 1 high-pressure cylinder having 7m³ of Oxygen gas is around ₹200-500, depending on the distance of the industry from the cylinder filling station) |
| PSA Oxygen Generator | ₹8.8 (on-site production considering a power tariff of ₹7/KWH) |
Please read our blog titled Comparison of the Cost of Oxygen Gas from Different Sources to understand more about different sources and prices.
Why Choose PSA Oxygen Generators?
Beyond cost savings, PSA Oxygen Plant offer many operational advantages:
- On-site Generation: No dependency on refilling schedules or delivery delays.
- Low Operational Pressure: Ensures safety with minimal storage and handling risks.
- Fully Automatic: Includes IDLE mode during low consumption to save energy.
- Low Carbon Footprint: No logistics = fewer emissions.
- Quick Return on Investment (ROI): PSA oxygen generators typically achieve ROI within 12 to 24 months.
As industries run on ROI (return on investment), oxygen generators are a boon, as the ROI for these machines is between 12 to 24 months compared to other sources of oxygen such as oxygen cylinders or liquid oxygen tanks.
For more details on ROI, please read our blog titled How to calculate the ROI (Return on Investment) of a PSA Oxygen generator compared to Liquid Oxygen or Oxygen Cylinders, or you can directly calculate the ROI in your specific surroundings and use case, using our ROI calculator, which you can find here.
Conclusion
With industries and healthcare systems demanding reliable, efficient, and safe oxygen solutions, PSA Oxygen Generators have emerged as the most economical and sustainable choice. By generating oxygen from ambient air on-site, businesses can eliminate logistics, lower costs, and reduce their carbon footprint.
Consult Us
For personalised consultation and to understand the best PSA Oxygen Plant setup for your application:
- Email: [email protected]
- Phone: 1800 3010 3394
- Website: www.absstem.com
References
- Absstem Technologies. (2025). Selecting the Right Oxygen Delivery System for Your Hospital
- Absstem Technologies. (2025). Comparison of the Cost of Oxygen Gas from Different Sources
- Absstem Technologies. (2024). How to calculate the ROI (Return on Investment) of a PSA Oxygen generator compared to Liquid Oxygen or Oxygen Cylinders
