Carbon Dioxide & Dry Ice Fact Sheet
What Is Carbon Dioxide & How Is It Used?
Carbon dioxide (CO2) is a compound of carbon and oxygen in proportions by weight of about 27.3% carbon to 72.7% oxygen. A gas at normal atmospheric temperatures and pressures, carbon dioxide is colorless, odorless, and about 1.5 times as heavy as air.
Carbon dioxide can exist as a gas, solid, or liquid.
Gaseous carbon dioxide is used primarily for the carbonation of soft drinks and beer. It is also used as a chemical in water treatment.
Liquid carbon dioxide is used for freezing and chilling of food products; carbonation of beverages; water treatment; low temperature testing of aviation and electronic components; oil and gas well stimulations; and controlling chemical reactions. It is also used as a fire extinguishing agent in portable and built-in fire extinguishing systems.
Solid carbon dioxide – also known as dry ice – is extremely cold (−109 °F / −78 °C) and is used extensively in vaccine cooling, food chilling and freezing, blood and tissue sample preservation, heat treating of metals, and even to create special effects such as fog for events or stage productions.
Where Does Carbon Dioxide Come From?
Carbon Dioxide in the Atmosphere
According to NASA, Earth’s atmosphere is made up of roughly 78.09% nitrogen, 20.95% oxygen, and 0.93% argon. Carbon dioxide is one of several trace gases (along with methane, nitrous oxide, and ozone) that account for the remaining 0.03% of Earth’s atmosphere.
Sources of Carbon Dioxide for Commercial Use
Large quantities of carbon dioxide for commercial use are primarily obtained from geological reserves or from by-product gas streams from one of the following processes:
- Ammonia production
- Ethyl alcohol production
- Hydrogen production
- Ethylene oxide production
- Synthetic natural gas production
- Acid neutralization
- Power plant combustion
Carbon dioxide is contained, shipped, and stored in liquid, gas, or solid form.
Carbon dioxide is generally liquefied by compression and refrigeration for storage or shipment.
Dry Ice – How Is It Produced?
Solid carbon dioxide is manufactured by decreasing the pressure of liquid CO2 until the point at which dry ice and cold vapor are formed.
Solid carbon dioxide is then compressed into blocks of dry ice, cut or formed into slabs or slices, or extruded into pellets. Dry ice for vaccine cooling is primarily supplied in pelletized form, in a variety of sizes.
For information about the safe handling, transport, and use of dry ice, as well as more detailed carbon dioxide product information, visit CGA’s Dry Ice Safety Resource Center.
This fact sheet is provided by the Compressed Gas Association (CGA). Founded in 1913, CGA is dedicated to the development and promotion of safety standards and safe practices in the industrial, medical, and food gases industry. CGA represents more than 130 member companies including manufacturers, distributors, suppliers, and transporters of gases, cryogenic liquids, and related products and services.