Liquid oxygen is a cryogenic form of oxygen that exists in a liquid state at extremely low temperatures (down to –183 °C) and under high pressure (101.325 kPa). It is pale or light blue and exhibits pronounced cryogenic properties. Industrially, it is produced using air separation equipment and is widely used to enhance combustion and support oxidation processes across a range of industries.
Physical Properties and Characteristics
- Boiling point: –182.98 °C. At this temperature, liquid oxygen transitions to gas.
- Thermal conductivity: High. It efficiently transfers heat to surrounding materials.
- Density: Approximately 1.14 g/cm³. Heavier than air and prone to accumulating in low-lying areas.
- Expansion on freezing: Like water, liquid oxygen expands when it freezes, which may lead to container rupture if not properly managed.
- Viscosity: Low. Flows easily through pipelines and containers.
- Colour: Distinct light blue hue.
Production Process
Liquid oxygen is produced by compressing and purifying ambient air, then cooling it to cryogenic temperatures near –183 °C. At this point, oxygen condenses into liquid form. It is stored and transported in insulated cryogenic tanks to maintain its low temperature.
Applications of Liquid Oxygen
Liquid oxygen is used in a broad range of fields, including:
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Medicine
It is convenient for storage and transport and is vaporised into gaseous form before being delivered to medical gas systems. Pure or mixed with other gases, it is used in respiratory therapies for conditions such as COPD, asthma, and pneumonia. It also finds application in surgery, intensive care, and treatment of cerebral oedema. Oxygen-enriched drinks, or “oxygen cocktails,” have gained popularity in wellness settings.
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Aerospace
Used as an oxidiser in rocket engines and as a breathable atmosphere component aboard spacecraft and space stations.
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Industry
Applied in metal cutting and welding, glass production, manufacturing of chemicals and explosives, and in cooling and cryogenic material treatment.
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Energy sector
Enhances fuel combustion in power generation systems, including gas turbines and thermal power plants.
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Scientific research
Employed in physics, chemistry, biology, and astronomy experiments. Enables the cooling of samples to extremely low temperatures, making it possible to study various physical and chemical properties under cryogenic conditions.
These represent only a portion of liquid oxygen’s potential uses. Its versatility makes it an indispensable resource across numerous fields.
Safety Considerations
While liquid oxygen is not toxic, it poses several safety hazards that require careful handling:
- Direct contact can cause severe frostbite. Appropriate cryogenic protective clothing is essential.
- Hot work such as welding or repairs should be delayed for 2–3 hours after handling liquid oxygen.
- Avoid any contact with flammable substances (e. g., oils, greases, fuels) for at least 20–30 minutes after oxygen exposure.
- Before transfer operations, a small purge of the system is necessary to pre-cool the transfer lines.
ONH Systems designs, manufactures, and supplies oxygen generators and oxygen supply stations. We customise equipment to meet specific client requirements and ensure timely delivery to your facility.
For details, call: +7 (495) 150-44-22.