Carbon DIoxide, CO2, or Super-Gas?

Spec Air Specialty Gases is a trusted supplier of carbon dioxide to Auburn and surrounding areas.

Many people not affiliated with the industrial gas industry are familiar with carbon dioxide, CO2, as the carbonation 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

At the start of the 1600’s, CO2 was discovered as the product of wood burning by a Finnish scientist named Jan Baptista von Helmont. In the mid 1700’s Joseph Priestly, an English chemist, discovered sparkling water through the process of combining water and CO2 dissipated from a fermentation process which changed the taste of water and initiated the start of the soft drink industry.

One of the attributes of the gas that was found was its ability to be easily liquefied. This resulted in it becoming the first commercial industrial gas to be supplied as a packaged gas. As more was understood, CO2 became the only gas offered and utlizied in all three of its phases – gas, liquid and solid.


For those involved in the gas industry, CO2 is most commonly associated with welding as a shielding gas and as a refrigerant in the food industry. CO2 also has other attributes that contribute to its uniqueness .

The prime 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 adjust the pH in certain applications where the pH is an important system parameter. This is prominent in some 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 requires water to form the acid so it remains CO2 until needed and is not considered hazardous like other acids.


CO2 is stored as a liquid regardless of the container. The pressure in an uninsulated CO2 cylinder is usually around 800 psig depending on the ambient temperature. The result is that any application using liquid CO2 has be under pressure. Employees in the oil industry are aware of CO2 replacing water in enhanced oil recovery (EOR) where the liquid is mixed with sand or sand like substance (proppant) and pumped down an oil well to recover oil that has been trapped between layers of rock. EOR is a wide-ranging term that can refer to several different processes but the most prominent is fracking. In this case man made fissures are used to pump the propant into rocks that are rich in oil. As a result, the rock fractures and the trapped oil is released. When used in place of water, CO2’s natural expansion of volume from liquid to gas increases the size of the fissure and leads to the recovery of more oil.

It’s not common knowledge that liquid CO2 is also applied in dry cleaning. In a special high pressure washer, liquid CO2 is used 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 extracted to be recycled and when the clothing is taken out and is clean and not wet since there was no water applied.

Every chemical (element or compound) has a state in which the three phases (gas, liquid and solid) have the same qualities and is reached through modification of temperature and pressure; this is known as the supercritical state. The supercritical state of CO2 can be produced in a specially designed processor. Because it is an excellent solvent, CO2 in its fluid phase is used to extract fragrances and color from flowers and plants. The process is, of course, performed under high pressure and requires highly specialized equipment.


Solid CO2 or dry ice is utilized applied in many different ways as a coolant. When liquid CO2 is moved through a high pressure line and passed through special nozzles, it instantly turns to CO2 snow and is used in the refrigeration or freezing of food. Dry ice pellets can be used in plae of regular ice in cases that hold perishables for long road transportation.

Dry ice in very small form is (about the size of a grain of rice) applied as an abrasive to rid surfaces of coatings without hurting the surface itself by blasting the rice size pellets through a blasting lance. This is prominent in the aircraft industry where the airplane’s bodies need to remain unharmed and not be damaged from sand blasting. An additional benefit is that there is no need to separate the removed coating from the abrasive as the pellets sublimate to CO2 gas leading to a cleanup that is quite easy.

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

To learn more about how you can be supplied with carbon dioxide in Auburn for any of your specialty gas operations, call Spec Air Specialty Gases at or at

John Segura, PE

About the Author

John Segura is a licensed Professional Engineer and a well-rounded executive in the industrial gas trade. He has worked for over 30 years with both domestic and international experience handling operations, marketing, and sales. Segura has been a leader to several teams of technicians and engineers through his work as an R&D manager for dominant gas companies. His work lead him to running the marketing efforts of technology worldwide industrial gas suppliers. He now consults to the industry on the business specializing in operations, applications and marketing.