Carbon DIoxide, CO2, or Super-Gas?

Greco Gas is a trusted supplier of carbon dioxide to Pittsburgh and surrounding areas.

Most people not involved the industrial gas industry are familiar with carbon dioxide, CO2, as the bubbles in soda and as the chemical in fire extinguishers. However, so many different forms of CO2 are employed in the industrial gas industry that it is one of the most versatile gases on the market

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 a chemist in England, Joseph Priestly, found that mixing water and CO2 being expended from a fermentation process created sparkling water which changed the taste of water and initiated the start of the soft drink industry.

One of the characteristics of the gas that was found was it’s simple liquefaction process. This led to CO2 being the first commercial industrial gas to be offered as a packaged gas. Eventually, after learning more about the gas, CO2 became the only gas offered and applied in all three of its phases – gas, liquid and solid.


Most of us in the industry associate CO2 with welding as a shielding gas and as a refrigerant in the food industry. There are also additional unique properties of CO2 that contribute to its versatility .

The prime example is when CO2 comes in contact with water and it forms carbonic acid. Although it is not a very powerful acid, it is an acid nonetheless and is employed to regulate the pH in some cases where the pH is an imperative system parameter. This is evident in specific industries such as paper production, textiles, and water treatment processes. One more plus is that carbonic acid is not stored as an acid (such as sulfuric or hydrochloric acids). As mentioned, the CO2 needs water to generate 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 atmospheric temperature. This means that any process using liquid CO2 has be under pressure. Workers in the oil industry are aware can compensate for water in enhanced oil recovery (EOR) where the liquid is combined with sand or sand like substance (proppant) and pumped down an oil well to recover oil that is trapped inside the rock layers. 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. This leads to the fracture of the rock and the subsequent release of the oil inside of it. When used in place of water, CO2’s natural expansion of volume from liquid to gas helps enlarge the fissure and recover an additional amount of oil.

It’s not common knowledge that liquid CO2 is also used to dry clean clothing. In a special 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 taken out 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 qualities and is attained adjusting the pressure and temperature; this is referred to as 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 moved through a high pressure line and passed through special nozzles, it instantly becomes CO2 snow and utilized to refrigerate and freeze food. Dry ice pellets can be used in plae of regular ice in bins that hold perishables for long road transportation.

Extremely small pieces of dry ice are (about the size of a grain of rice) applied as an abrasive to remove coatings from surfaces without causing damage the surface itself by shooting the rice size pellets through a blasting lance. This is prominent in the aircraft industry in which the body of an airplane must remain intact and not suffer from the harm that sand blasting would cause. Another advantage is that the removed coating does not require separating from the abrasive as the pellets sublimate to CO2 gas resulting in a simple cleanup.

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

To find out more about how you can be supplied with carbon dioxide in Pittsburgh for any of your specialty gas operations, call Greco Gas at (724) 226-3800 or at

John Segura, PE

About the Author

John Segura is a licensed Professional Engineer and a well-rounded executive in the industrial gas industry. He has over 30 years of experience covering sales, marketing and operations both domestic and international. 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.