| Reduces pressure of air leaving the air storage tank and supplies compressed air at set pressure to PSA generator. |
Photo: Nadia Todres
PSA Basics
Pressure Swing Adsorption (PSA) plants contain the following components
Air compressor
| Intakes and compresses air |
Air dryer
| Removes moisture from compressed air. Two types of air dryers are common:
1) Refrigerant dryer, which extracts moisture by cooling the air, and; 2) Desiccant dryer, which uses desiccant to absorb moisture out of the air. |
Coalescing filters
| Removes oil, water and dust particles from the compressed, dried air before it gets to the oxygen generator. |
Air storage tank
| Stores dry, clean compressed air to send to PSA oxygen generator. |
Feed air regulator
PSA oxygen generator system
| Sieve beds: PSA oxygen generators have sieve beds that are cyclically pressurized and depressurized. Sieve beds contain a porous material called zeolite that adsorbs nitrogen at high pressures and allows oxygen to pass.
Valves: Direct the flow of gases(compressed air, nitrogen and oxygen) in the PSA generator Programmable Logic Controller (PLC): Controls the overall PSA process by controlling how long the valves open and close to direct the flow of compressed air, nitrogen and oxygen. Backpressure regulator: Maintains pressure in PSA generator and regulates volume and purity of oxygen. Not all models of PSA oxygen generators have this component. Exhaust Muffler: Vents nitrogen from the PSA oxygen generator and muffles sounds. Oxygen Storage Tank: Receives concentrated oxygen from the PSA oxygen generator and stores oxygen for distribution (between 4-7 bar [58-100 psi]). Booster Compressor: Compresses oxygen to fill cylinders at high pressure (3-6 bar → 150 bar) |
Filling manifold
| Interface between the booster compressor and the cylinders. |
Backup manifold
| Emergency cylinder reserve that can supply oxygen to the pipeline when the primary source of oxygen is unavailable (such as during power outages or scheduled maintenance). |
Automatic changeover system
| Maintains a constant oxygen supply via a duplex set of regulators by switching between the primary and secondary oxygen supply |
Oxygen regulator
| Maintains constant pressure in the oxygen pipeline. |
Outlets
| Terminal units installed at patient beds to access piped oxygen with flowmeters. Outlets are gas- and standard-specific. |
Containerized Plants
| Plant arrives onsite pre-installed in a shipping container which rests outdoors on a concrete slab. These plants usually are simpler to install but cost more |
Individual Component Plant
| Plant equipment arrives onsite and must be individually installed on a skid or directly to the floor of a plant house or a plant room in the existing hospital infrastructure. |
Skid Mounted Plants
| Plant equipment arrives onsite and must be individually installed on a skid or directly to the floor of a plant house or a plant room in the existing hospital infrastructure. |
All-in-One Plants
All-in-one plants (these types of plants can be housed in containers or in dedicated oxygen plant rooms within buildings)
Cylinder-Filling Oxygen Plants
| Oxygen is concentrated and then compressed into medical oxygen cylinders, which can be easily moved around and used at the bedside or to a supply manifold system. Cylinder filling systems can be shipped almost completely assembled but the high-pressure oxygen compressors then require frequent specialized maintenance. Empty cylinders need to be replaced multiple times per day. |
Pipeline Plants
| Oxygen is concentrated, passed through a regulator, and piped directly to bedside wall outlets throughout the facility. Pipelines require specialized construction techniques and materials and must be assembled on-site but require little ongoing maintenance after installation. Modifying pipelines after installation is difficult and costly. No additional staff are required to fill or regularly maintain pipelines, so while the upfront costs of the plant may be higher than cylinder plants, the recurring costs are lower. |
Combination Cylinder-Filling and Piping Plants
Single
Duplex
Triplex
