Carbon DIoxide, CO2, or Super-Gas?

Coastal Welding Supply is a trusted supplier of carbon dioxide to Beaumont and surrounding areas.

Most people not involved the industrial gas industry recognize carbon dioxide, CO2, as the bubbles in soft drinks and as the chemical in fire extinguishers. But CO2 is utilized in so many different forms that it is actually one of the most versatile gases available

Brief History

CO2 was discovered in the early 1600’s as the off gas of burning wood by Jan Baptista von Helmont, a scientist in Finland. In the mid 1700’s an English chemist named Joseph Priestly, found that mixing water and CO2 being expended from a fermentation process created sparkling water which altered the water’s taste and was the driving force behind the start of the soft drink industry.

One of the characteristics of the gas that was found was how easily it could be liquefied. The result was that CO2 became the first commercial industrial gas to be supplied as a packaged gas. As more was understood, CO2 became the only gas supplied and used in all three of its phases – gas, liquid and solid.


CO2 is most often associated by those in the gas industry as a refrigerant in the food and beverage industry and as a shielding gas in welding. Other characteristics make it unique as well .

The most fitting example is when CO2 creates carbonic acid after coming into contact with water. Although it is a weak acid, it is an acid nonetheless and has the ability to modify the pH in some cases where the pH is an important system parameter. This is the case in different industries such as paper production, textiles, and water treatment processes. Another advantage is that carbonic acid is not stored as an acid (such as sulfuric or hydrochloric acids). As mentioned, the CO2 needs water to create the acid so it remains CO2 until needed and is not considered dangerous like several acids.


CO2 is stored as a liquid regardless of the container. The pressure in an uninsulated CO2 cylinder is approximately around 800 psig depending on the ambient temperature. The outcome of this is that any process using liquid CO2 must be under pressure. Workers in the oil industry are aware that CO2 takes the place of water in enhanced oil recovery (EOR) where the liquid is put in a blend with sand or sand like substance (proppant) and propelled through an oil well to recover oil that has been trapped between layers of rock. EOR is a blanket term to describe different applications but the most prominent is fracking. In this case a propant is pushed into rocks rich with oil with the use of man-made devices. This forces the rock to fracture and release trapped oil. When used in place of water, CO2’s natural expansion of volume from liquid to gas makes the fissure larger and helps recover additional oil.

It is not commonly known that liquid CO2 is also applied in dry cleaning. In a special high pressure washer, liquid CO2 is introduced with a stain remover. The laundry is then cleaned in a normal fashion using turbulence to clean the wash. When the cycle is completed, the dirt, grime and stain remover are separated from the liquid CO2. The liquid CO2 is then removed for reuse and the laundry is removed clean and dry since no water was used.

Every chemical (element or compound) has a state in which the three phases (gas, liquid and solid) have the same attributes and is attained adjusting the pressure and temperature; this is called the supercritical state. The supercritical state of CO2 can be created in a specifically designed processor. The fluid phase of supercritical CO2 is an exceptional solvent and is used to extract fragrances and color from flowers and plants. This process requires specific equipment and is carried out under high pressure.


Solid CO2 or dry ice is utilized applied in many different ways as a coolant. When liquid CO2 is sent through a high pressure line and released using special nozzles, it instantly becomes CO2 snow and utilized to refrigerate and freeze food. Dry ice pellets act as a replacement for regular ice in tubs that hold perishables for long over-the-road transport.

Very small cuts of dry ice are (about the size of a grain of rice) utilized as an abrasive to eliminate coating on surfaces without damaging the surface itself by blasting the rice size pellets through a blasting lance. This is prevalent in the aircraft industry where the airplane’s bodies need to remain unharmed and not be damaged from sand blasting. This is also advantageous because is that the removed coating does not have to be separated from the abrasive as the pellets sublimate to CO2 gas leading to a cleanup that is quite easy.

Referring to CO2 as a super-gas may be debatable, but it is certainly the most versatile element available in the industrial gas market.

To learn more about how you can obtain carbon dioxide in Beaumont for any of your specialty gas operations, call Coastal Welding Supply at 800-852-4177 or at

John Segura, PE

About the Author

John Segura is a licensed Professional Engineer and an experienced executive in the industrial gas industry. He has worked for over 30 years with both domestic and international experience handling operations, marketing, and sales. Segura has led teams of engineers and technicians as an R & D manager for major gas companies. His work directed him to lead the marketing efforts of technology worldwide industrial gas suppliers. Now, he acts as an industry consultant on the business specializing in operations, applications and marketing.