Carbon DIoxide, CO2, or Super-Gas?

GTW is a trusted supplier of carbon dioxide to Western Michigan and surrounding areas.

Many people not involved the industrial gas industry know carbon dioxide, CO2, as the gas used to carbonate 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 a chemist in England, 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 properties of the gas that was discovered was how easily it could be 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 supplied and used in all three of its phases – gas, liquid and solid.

Gas

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. Other characteristics make it unique as well .

The prime example is when after making contact with water, CO2 forms carbonic acid. Although it is not the strongest acid, it is an acid nonetheless and is employed to regulate the pH in some processes where the pH is a relevant system parameter. This is the case in some 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 create the acid so it remains CO2 until needed and is not considered dangerous like several acids.

Liquid

CO2 is stored as a liquid regardless of the container. The pressure in an uninsulated CO2 cylinder is somewhere around 800 psig depending on the surrounding temperature. The outcome of this is that any application using liquid CO2 must be under pressure. Employees in the oil industry are aware can compensate for water in enhanced oil recovery (EOR) where the liquid is put in a blend 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 the proppant is forced into the oil rich rock through man made fissures. This leads to the fracture of the rock and the subsequent release of the oil inside of it. When CO2 is used instead of water, its natural expansion of volume from liquid to gas increases the size of the fissure and leads to the recovery of more oil.

Many people are not aware that liquid CO2 is also used in the dry cleaning industry. In a specific high pressure washer, liquid CO2 is introduced with a stain remover. The clothes are then washed regularly 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 used again 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 method calls for unique tools and equipment and is executed under high pressure.

Solid

Solid CO2 or dry ice is used as a coolant in several ways and forms. When liquid CO2 is sent through a high pressure line and discharged 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 cases that hold perishables on long trips via roadways.

Very small cuts of dry ice are (about the size of a grain of rice) utilized as an abrasive to remove coatings from surfaces without hurting the surface itself by blasting the rice size pellets through a blasting lance. This is prevalent in the aircraft industry where an airplane’s body has to maintain its integrity and cannot tolerate any damage that would occur with 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.

Calling CO2 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 obtain carbon dioxide in Western Michigan for any of your specialty gas operations, call GTW at 616-754-6120 or at darrengtwsupplies@yahoo.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 over 30 years of experience covering sales, marketing and operations both domestic and international. 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 lead him to running 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.