Carbon DIoxide, CO2, or Super-Gas?

Sidney Lee Medical & Scientific Gases is a trusted supplier of carbon dioxide to Atlanta, GA and surrounding areas.

Most people outside the industrial gas industry recognize carbon dioxide, CO2, as the bubbles in soda and as the chemical in fire extinguishers. CO2 is used in more forms than any other gas in the industrial gas market making it one of the most versatile products sold

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 a chemist in England, Joseph Priestly, discovered sparkling water through the process of combining water and CO2 dissipated from a fermentation process which gave the water a different taste and became the basis for the soft drink industry.

One of the properties of the gas that was found was it’s simple liquefaction process. This resulted in it becoming the first commercial industrial gas to be offered as a packaged gas. As more was understood, CO2 became the only gas sold 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 the food and beverage industry for its use as a refrigerant or as a shielding gas in welding. There are also additional unique properties of CO2 that contribute to its versatility .

The most fitting example is when CO2 comes in contact with water and it forms carbonic acid. 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 a relevant 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 requires water to form 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 usually around 800 psig depending on the atmospheric temperature. The outcome of this is that any process using liquid CO2 has be under pressure. Employees in the oil industry are aware that CO2 takes the place of water in enhanced oil recovery (EOR) where the liquid is combined with sand or sand like substance (proppant) and sent down 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. Here a propant is pushed into rocks rich with oil with the use of man-made devices. As a result, the rock fractures and the trapped oil is released. When CO2 is used instead of water, its natural expansion of volume from liquid to gas makes the fissure larger and helps recover additional oil.

Many people are not aware that liquid CO2 is also applied in dry cleaning. In a specific high pressure washer, liquid CO2 is mixed with a stain remover. The laundry is treated as in a regular washing machine using turbulence to clean the wash. When the cycle is finished, the dirt, grime and stain remover are separated from the liquid CO2. The liquid CO2 is then extracted to be recycled and the clean clothes are removed and has remained dry since there was no water utilized in the process.

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 produced in a specially designed processor. When in its fluid phase, CO2 is a great solvent and is utilized in the extracting of fragrances and color from flowers and plants. This method calls for unique tools and equipment and is executed under high pressure.


Solid CO2 or dry ice is applied in a wide variety of methods as a coolant. When liquid CO2 is sent through a high pressure line and released using special nozzles, it immediately becomes CO2 snow and is used in the refrigeration or freezing of food. Dry ice pellets replace regular ice in cases that hold perishables for long over-the-road transport.

Extremely small pieces of dry ice are (about the size of a grain of rice) applied as an abrasive to rid surfaces of coatings without hurting the surface itself by shooting 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. This is also advantageous because is that there is no need to separate the removed coating from the abrasive as the pellets sublimate to CO2 gas resulting in a simple cleanup.

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

To learn more about how you can get carbon dioxide in Atlanta, GA for any of your specialty gas operations, call Sidney Lee Medical & Scientific Gases at 770-946-4287 or at

John Segura, PE

About the Author

John Segura is a licensed Professional Engineer and an experienced executive in the industrial gas world. 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 caused his eventual leadership of the marketing efforts of technology worldwide industrial gas suppliers. He now consults to the industry on the business specializing in operations, applications and marketing.