Both liquid oxygen and oxygen are widely used in industrial and research fields. Understanding the differences between the two is essential for selecting the appropriate form of oxygen for specific needs. Liquid oxygen is the liquid form of oxygen, suitable for specific industries such as aerospace. Oxygen, on the other hand, is a gaseous form at normal temperature and pressure, and is crucial for sustaining life and various chemical reactions. A detailed comparison helps users make more informed choices.
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Liquid oxygen is the form of oxygen that has been liquefied at extremely low temperatures, making it suitable for aerospace, industrial, and certain medical fields. Its low temperature characteristics provide a high expansion ratio and strong oxidizing power, but it requires special storage and transport conditions and is more expensive. Oxygen, in its gaseous state at normal temperature and pressure, is more commonly used and widely applied in medical, chemical, and metalworking industries. It is easier to store and transport and is more cost-effective.
Oxygen is the second most abundant element in Earth’s atmosphere, making up about 21% of the air by volume. It plays a key role in biological respiration, combustion, and many other processes, with a broad range of applications in various fields. Understanding the basic properties of oxygen is fundamental to grasping the differences between liquid oxygen and gaseous oxygen.
Oxygen is a chemical element with an atomic number of 8, symbolized by O.
Liquid oxygen is the liquid form of oxygen, created by cooling gaseous oxygen below its boiling point. It has unique physical and chemical properties that make it important for certain applications.
Liquid oxygen is the liquefied form of oxygen that results from cooling oxygen to below its boiling point.
Typically produced through air separation methods, where air is compressed and cooled to liquefy it. Oxygen is then separated using distillation and further cooled to the liquid state based on differences in boiling points between oxygen and nitrogen.
Liquid oxygen is a pale blue transparent liquid with a boiling point of -183°C and a density of 1.14g/cm³. It has a high expansion ratio, where 1L of liquid oxygen can vaporize to approximately 800L of gaseous oxygen.
Oxygen is the most common gaseous form of the oxygen element in nature, widely present and irreplaceable in various industrial and scientific research applications.
Oxygen is a diatomic molecule, consisting of two oxygen atoms bound by a covalent bond, with the molecular formula O₂.
Primarily produced on a large scale through air separation techniques, though it can also be generated through water electrolysis.
Oxygen is a colorless, odorless gas at normal temperature and pressure, chemically reactive, and can undergo oxidation reactions with many substances, especially under high-temperature conditions.
Liquid oxygen and oxygen gas differ significantly in several aspects, which determine their respective applications, advantages, and disadvantages.
Liquid oxygen is in a liquid state at extremely low temperatures, whereas oxygen is in a gaseous state. The low-temperature characteristic of liquid oxygen makes it suitable for situations requiring ultra-low temperatures or as a strong oxidizing agent, such as in aerospace propulsion. Liquid oxygen can react violently with fuel to produce a large amount of energy, thus powering spacecraft. Oxygen, on the other hand, is more convenient for participating in various chemical reactions and biological processes at normal temperature and pressure.
Liquid oxygen must be stored in special low-temperature insulated containers, such as Dewar flasks or large liquid oxygen tanks, to prevent rapid vaporization. During transportation, strict insulation measures must be taken, and specialized equipment is used. Oxygen can be stored and transported more conveniently in high-pressure gas cylinders, making it more flexible and easier to handle.
The production and storage of liquid oxygen require a significant amount of energy to maintain the low-temperature environment, and the investment and maintenance costs for the required equipment are relatively high. Therefore, the cost of liquid oxygen is higher. Oxygen, however, has relatively lower production and storage costs, especially for low-purity and small-scale oxygen use, where its cost advantages are more pronounced.
Liquid oxygen’s low temperature can cause severe frostbite, and when it vaporizes, it rapidly produces a large volume of gas, which may lead to dangerously high local oxygen concentrations, posing a risk of fire or explosion. Although oxygen itself is non-combustible, it is an oxidizer, and in high-concentration environments, it can contribute to fires or explosions. Therefore, safety precautions must be taken when using and storing oxygen, keeping it away from ignition sources and flammable materials.
This method utilizes the differences in the adsorption abilities of solid adsorbents for gases. At a certain pressure, impurity gases are adsorbed, allowing oxygen to pass through the adsorption bed. Impurities are desorbed through pressure reduction, enriching the oxygen. This can be done in a dual-bed or multi-bed system that alternates and cycles for continuous production.
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Air is compressed and cooled to liquefy it. By utilizing the different boiling points of liquid nitrogen and liquid oxygen, the separation is achieved in a distillation column where nitrogen vaporizes first, leaving liquid oxygen at the bottom.
This method separates gases based on the different permeation rates of gases through a polymer membrane. Smaller molecules (like oxygen) permeate faster than larger molecules under a pressure differential. This process uses hollow fiber membrane modules to enrich oxygen.
Similar to the cryogenic oxygen production process, air is first deeply cooled and liquefied. In the distillation process, liquid oxygen is separated. Further cooling and compression of oxygen occurs, and below the critical temperature, it is pressurized to liquefy, storing it in a low-temperature insulated container.
In this method, oxygen gas is first obtained using PSA or membrane separation methods, then compressed and cooled to a liquid state using specialized equipment. This process requires an efficient refrigeration system and pressurized liquefaction devices.
Has strong oxidative properties and can serve as an efficient oxidizer, providing powerful thrust for rockets and other applications. Its low-temperature characteristics make it suitable for special processes such as superconducting research and low-temperature treatment of certain materials.
Essential for sustaining life, it plays an irreplaceable role in medical emergencies and is widely used in industries such as chemical manufacturing and metalworking. As a common oxidizer, it promotes chemical reactions and enhances processing efficiency.
Storage and transportation conditions are demanding, making it costly, with risks of cryogenic burns and safety hazards.
It cannot replace liquid oxygen in applications requiring extremely low temperatures or high energy density, and improper handling or storage can lead to fire hazards and other safety accidents.
Liquid oxygen and oxygen gas each have their distinct characteristics and advantages, playing vital roles in various fields. Choosing between liquid oxygen and oxygen gas based on specific needs and application scenarios is crucial to ensuring smooth operations in production, research, and daily life.
At MINNUO, with over 30 years of experience, we have become a leader in the gas solution field, committed to providing high-quality oxygen generation equipment and professional services. We look forward to your inquiries!
Simply place liquid oxygen in a normal temperature and pressure environment, and it will naturally absorb heat and vaporize into gaseous oxygen. In industrial and laboratory settings, the vaporization process can be accelerated by controlling the heating to meet different oxygen demands.
The oxygen in a typical oxygen cylinder is in a gaseous state. It is pressurized and filled into the cylinder through a compressor for storage and transportation. When used, the oxygen flow rate and pressure can be adjusted as needed. (Liquid oxygen requires special oxygen cylinders.)
Oxygen is a chemical element represented by the symbol O, while oxygen gas refers to a molecule composed of two oxygen atoms, with the molecular formula O₂, which is one of the most common forms of oxygen.
Discussion on the Safe Use of Medical Liquid Oxygen Dewar
HONG Hou-yun
China Medical Devices ›› , Vol. 29 ›› Issue (10) : 69-71.
PDF( KB) PDF( KB)Discussion on the Safe Use of Medical Liquid Oxygen Dewar