Carbon DIoxide, CO2, or Super-Gas?

Cee Kay Supply, Inc. is a trusted supplier of carbon dioxide to St. Louis and surrounding areas.

Many people not involved the industrial gas industry are familiar with carbon dioxide, CO2, as the carbonation in soft drinks 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

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 an English chemist named Joseph Priestly, discovered sparkling water through the process of combining water and CO2 dissipated from a fermentation process 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 unconvered was its ability to be easily liquefied. The result was that CO2 became the first commercial industrial gas to be offered as a packaged gas. As more was understood, CO2 became the only gas sold and used in all three of its phases – gas, liquid and solid.

Gas

CO2 is most often associated by those in the gas industry 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 most fitting 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 has the ability to adjust the pH in certain applications where the pH is an imperative system parameter. This is evident in specific 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 unlike many other acids, is not considered harmful.

Liquid

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 outcome of this is that any process using liquid CO2 has be under pressure. Workers in the oil industry are aware of CO2 replacing water in enhanced oil recovery (EOR) where the liquid is combined with sand or sand like substance (proppant) and propelled through an oil well to recover oil that is trapped inside the rock layers. EOR is a blanket term to describe different applications but the most common is fracking. Here the proppant is forced into the oil rich rock through man made fissures. 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 helps enlarge the fissure and recover an additional amount of oil.

It is not commonly known that liquid CO2 is also applied in dry cleaning. In a special high pressure washer, liquid CO2 is combined with a stain remover. The laundry is treated as in a regular washing machine applying 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 taken out to be used again 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 called the supercritical state. The supercritical state of CO2 can be generated in a uniquely 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

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 passed through special nozzles, it immediately becomes CO2 snow and is applied in food refrigeration and freezing. Dry ice pellets can be used in plae of regular ice in bins that hold perishables for long over-the-road transport.

Very small cuts of dry ice are (about the size of a grain of rice) used as an abrasive to eliminate coating on surfaces without damaging the surface itself by launching 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. 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 controversial, but it is easily the most versatile product available in the industrial gas market.

To find out more about how you can get carbon dioxide in St. Louis for any of your specialty gas operations, call Cee Kay Supply, Inc. at 314.644.3500 or at benv@ceekay.com.

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 been in the industry for over 30 years and is experienced in marketing, sales, and operations at both domestic and international levels. Segura has well-rounded experience leading teams of engineers and technicians from his years as an R&D manager for large gas companies. His work directed him to lead the marketing efforts of technology worldwide industrial gas suppliers. He still remains in the industry but now as a consultant on the business specializing in operations, applications and marketing.