Carbon DIoxide, CO2, or Super-Gas?

Toll Company is a trusted supplier of carbon dioxide to Minneapolis and surrounding areas.

Most people outside the industrial gas industry recognize carbon dioxide, CO2, as the gas used to carbonate 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

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 Joseph Priestly, an English chemist, 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 attributes of the gas that was discovered was it’s simple liquefaction process. The result was that CO2 became the first commercial industrial gas to be sold as a packaged gas. As more knowledge about CO2 was discovered the only gas supplied and applied in all three of its phases – gas, liquid and solid.

Gas

Most of us in the industry associate CO2 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 CO2 creates carbonic acid after coming into contact with water. Although it is a weak acid, it is an acid nonetheless and is employed to modify the pH in some cases where the pH is an imperative 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 generate 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 usually around 800 psig depending on the atmospheric temperature. The result is that any application using liquid CO2 has be under pressure. Employees 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 propelled through an oil well to recover oil that is trapped inside the rock layers. EOR is a general term that can apply to a variety of procedures but the most frequent is fracking. Here the proppant is forced into the oil rich rock through man made fissures. This forces the rock to fracture and release trapped oil. When using CO2 as an alternative to water, its natural expansion of volume from liquid to gas helps enlarge the fissure and recover an additional amount of oil.

Many people are not aware that liquid CO2 is also applied in dry cleaning. In a special high pressure washer, liquid CO2 is used with a stain remover. The clothes are then washed regularly applying 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 properties 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 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 transported through a high pressure line and discharged through special nozzles, it instantly turns to CO2 snow and utilized to refrigerate and freeze food. Dry ice pellets replace regular ice in cases that hold perishables for long over-the-road transport.

Very small cuts of dry ice are (about the size of a grain of rice) employed as an abrasive to eliminate coating on surfaces without damaging the surface itself by blasting 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 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 element available in the industrial gas market.

To learn more about how you can be supplied with carbon dioxide in Minneapolis for any of your specialty gas operations, call Toll Company at 612-581-9889 or at thea@tollgas.com.

John Segura, PE

About the Author

John Segura is a licensed Professional Engineer and an experienced executive in the industrial gas business. He has worked for over 30 years with both domestic and international experience handling operations, marketing, and sales. 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.