Carbon DIoxide, CO2, or Super-Gas?

Wright Brothers is a trusted supplier of carbon dioxide to Cincinnati and surrounding areas.

Many people outside the industrial gas industry are familiar with carbon dioxide, CO2, as the carbonation in certain beverages 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

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, found that mixing water and CO2 being expended from a fermentation process created sparkling water 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. This resulted in it becoming the first commercial industrial gas to be supplied as a packaged gas. Eventually, after learning more about the gas, CO2 became the only gas offered and utlizied in all three of its phases – gas, liquid and solid.

Gas

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. Other characteristics make it unique as well .

The most fitting example is when after making contact with water, CO2 forms carbonic acid. Although it is not a very powerful acid, it is an acid nonetheless and has the ability to modify the pH in certain applications where the pH is an important system parameter. This is the case in different 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 approximately 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 of CO2 replacing 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 has been trapped between layers of rock. EOR is a blanket term to describe different applications but the most frequent is fracking. Here a propant is pushed into rocks rich with oil with the use of man-made devices. 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 helps enlarge the fissure and recover an additional amount of oil.

It’s not common knowledge 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 laundry is treated as in a regular washing machine applying turbulence to clean the wash. When the cycle is done, the dirt, grime and stain remover are separated from the liquid CO2. The liquid CO2 is then extracted for reuse 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 reached through modification of temperature and pressure; this is referred to as 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. The process is, of course, performed under high pressure and requires highly specialized equipment.

Solid

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

Dry ice in very small form is (about the size of a grain of rice) employed as an abrasive to eliminate coating on surfaces without hurting the surface itself by shooting the rice size pellets through a blasting lance. This is popular 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. This is also advantageous because is that the removed coating does not require separating from the abrasive as the pellets sublimate to CO2 gas leading to a cleanup that is quite easy.

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

For more information on how you can get carbon dioxide in Cincinnati for any of your specialty gas operations, call Wright Brothers at 800-637-2222 or at mike@expectthebest.com.

John Segura, PE

About the Author

John Segura is a licensed Professional Engineer and a well-rounded executive in the industrial gas world. 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 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. Now, he acts as an industry consultant on the business specializing in operations, applications and marketing.