PSA/VPSA (vacuum Pressure Swing Adsorption) methods are the most common method for gas oxygen generation for medium- and small-scale applications. PSA generators separate oxygen from ambient air inside a pressurized tank filled with zeolite, the molecular sieve.
Membrane oxygen generators normally use a semi-permeable hollow-fiber membrane to separate oxygen and nitrogen. The system requires low start-up cost, is considered reliable due to containing no moving parts that can fail, but can only produce low purity oxygen of 30-50% and can cost a lot in case of repair, therefore not commonly used in general.
Chemical oxygen generators produce oxygen via chemical reacitons of inorganic superoxide e.g. sodium chlorate, perchlorate, ozonides, potassium superoxide. Chemical oxygen generators are often used in emergency situations for firefighting, mine rescue, submarines and space station.
PSA generators have obvious advantages in industrial and commercial applications over other methods in the following aspects.
Doer's PSA/VPSA oxygen generators produce oxygen with a purity of 93%, have a flexible capacity up to 200 Nm3/h and 6,000 Nm3/h per set respectively; In contrast, membrane oxygen generators have lower purity, normally 30-50% (nitrogen purity can reach 95%), less production capacity with higher purity demands.
PSA and VPSA can be used in different applications mainly depending on the scale of operations, they can be generally used in metal cutting, mining, aquaculture/fish farming, waste water treatment, oxygen-enriched conbustion, oxygen-enriched air conditioning, catalyticoxidation, etc.