|More Headlines | RSS Feed|
Cryogenic liquids (also known as cryogens) are liquefied gases that are stored in their liquid states at very low temperatures. They have boiling points below -238°F (-150°C), with the exception of carbon dioxide and nitrous oxide, which are sometimes included in this group.
Cryogenic liquids have unique temperatures and pressures at which they liquefy, but they share two things in common.
- All cryogens are extremely cold.
- Small amounts of cryogenic liquid can expand into very large volumes of gas (which is also very cold).
Types of Cryogenic Liquids
Most cryogenic liquids can be categorized into one of three groups.
- Inert Gases: These gases are generally not chemically reactive and do not burn or support combustion. Examples are nitrogen, helium, neon, argon and krypton.
- Flammable Gases: These gases can burn in air. Examples are hydrogen, methane and liquefied natural gas.
- Oxygen: The presence of liquid oxygen can cause many materials normally considered non-combustible to burn. Organic materials may react explosively in its presence. Its hazards and handling precautions, therefore, are unique.
Storing Cryogenic Liquids
Cryogenic liquid containers are thermally insulated and must be able to withstand rapid changes and extreme differences in temperature. Dewar flasks are commonly used, along with other cylinders. See also: cryogenic bulk tank.