1. Oxygen Supply via Liquid Oxygen Tank Vaporization
This oxygen supply system consists of liquid oxygen tanks, vaporizers, pressure reducing devices and pipelines. The liquid oxygen stored in the tanks is produced by cryogenic air separation plants and delivered by liquid oxygen tankers.
It delivers oxygen with high purity up to 99.9%. The liquid oxygen tank operates at approximately -180 ℃ and 0.8 MPa. Classified as Category B production facility, it carries certain fire hazards. All equipment and pipelines fall under special equipment and pressure piping, which require regular supervision and inspection.
Compared with Pressure Swing Adsorption (PSA) oxygen generation, Vacuum Pressure Swing Adsorption (VPSA) oxygen generation and membrane separation oxygen supply, this solution requires lower initial investment but higher operating cost. Calculated at 900 RMB per ton of liquid oxygen, the oxygen cost under standard conditions is about 1.3 RMB per cubic meter.
2. Pressure Swing Adsorption (PSA) Oxygen Generation
For PSA molecular sieve oxygen supply, ambient air is compressed by an air compressor and fed into molecular sieve adsorption towers. Adsorption proceeds under high pressure (0.3~0.8 MPa), and desorption takes place at atmospheric pressure. Two sets of adsorption towers operate alternately automatically, and oxygen stored in the gas tank is delivered to oxygen supply rooms through pipelines. Since inert gases such as argon in air cannot be removed, the oxygen volume fraction of the produced gas is only around 93%.
As air needs to be compressed to 0.3~0.8 MPa by the compressor, PSA consumes more energy than VPSA. When the pipeline pressure reaches 0.3~0.8 MPa with large oxygen supply capacity, pipelines with a nominal diameter (DN) of 50 mm or above are categorized as pressure piping. In addition, oxygen storage tanks are pressure vessels. Both the oxygen storage tanks and DN≥50 pipelines are subject to regular supervision and inspection. The energy consumption of PSA is about 1.5-2.5 kWh per standard cubic meter. Based on an electricity price of 0.6 RMB/(kW·h), the production cost of oxygen is approximately 1.0 RMB per cubic meter.
3. Membrane Separation Oxygen Supply
This technology separates gas components by utilizing the difference in permeation rates of various gases across gas separation membranes. The oxygen volume fraction of conventional oxygen-enriched gas produced is generally 30%~45%. Adopting multi-cycle membrane separation technology to remove nitrogen and argon can raise the oxygen volume fraction up to 99.5%. This method is widely applied in hospitals and logistical support for troops in plateau regions.
4. Vacuum Pressure Swing Adsorption (VPSA) Oxygen Generation
In the VPSA process, air is delivered into molecular sieve adsorption towers by a low-pressure air compressor. Adsorption occurs at atmospheric pressure or slightly above (0~50 kPa), while desorption is completed under vacuum. Similar to PSA, inert gases like argon cannot be eliminated, so the oxygen volume fraction is maintained at around 93%.
Oxygen generators manufactured by Chengdu Lianbang Medical Technology Co., Ltd. adopt this advanced VPSA technology, featuring outstanding advantages of low pressure, oil-free operation and low energy consumption. The system operates at a pressure below 0.1 MPa, involving no pressure vessels or pressure pipelines, so mandatory regular inspections are not required. This greatly reduces operation & maintenance barriers and regulatory costs. Its energy consumption is as low as 0.4-1.0 kWh per standard cubic meter. With an electricity price of 0.6 RMB/(kW·h), the oxygen production cost is roughly 0.4 RMB per cubic meter, presenting prominent cost advantages over other oxygen supply solutions.
Furthermore, the oil-free design of Lianbang's VPSA oxygen generators guarantees pure and contamination-free oxygen, making them ideal for scenarios with strict requirements on oxygen quality and operating costs, such as hospitals and plateau areas. With lower initial investment and less energy consumption than traditional PSA systems, they serve as an optimal alternative to liquid oxygen supply and high-pressure PSA oxygen generation.