Carbon DIoxide, CO2, or Super-Gas?

WestAir Specialty Gases and Equipment is a trusted supplier of carbon dioxide to Southern California and surrounding areas.

Many people not involved the industrial gas industry recognize carbon dioxide, CO2, as the carbonation in 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 an English chemist named Joseph Priestly, found that mixing water and CO2 being expended from a fermentation process created sparkling water which gave the water a different taste and became the basis for the soft drink industry.

One of the characteristics of the gas that was unconvered was how easily it could be liquefied. The result was that CO2 became the first commercial industrial gas to be supplied as a packaged gas. As more knowledge about CO2 was discovered the only gas offered 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 welding as a shielding gas and as a refrigerant in the food industry. CO2 also has other attributes that contribute to its uniqueness .

The most fitting example is when CO2 creates carbonic acid after coming into contact with water. Although it is not the strongest acid, it is an acid nonetheless and is employed to adjust the pH in some cases where the pH is an important system parameter. This is the case in certain 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 calls for water to generate the acid so it remains CO2 until needed and is not considered hazardous like other 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 must be under pressure. Employees in the oil industry are aware can compensate for water in enhanced oil recovery (EOR) where the liquid is mixed with sand or sand like substance (proppant) and sent down an oil well to recover oil that is stuck between rock layers. EOR is a blanket term to describe different applications but the most prominent is fracking. In fracking 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 increases the size of the fissure and leads to the recovery of more oil.

It is not commonly known that liquid CO2 is also used to dry clean clothing. In a certain high pressure washer, liquid CO2 is used with a stain remover. The laundry is then cleaned in a normal fashion 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 removed 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 qualities and is achieved through proper adjustment of temperature and pressure; this is known as the supercritical state. The supercritical state of CO2 can be produced in a specially 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 moved through a high pressure line and discharged through special nozzles, it instantly transforms into CO2 snow and is applied in food refrigeration and freezing. Dry ice pellets replace regular ice in tubs that hold perishables on long trips via roadways.

Extremely small pieces of dry ice are (about the size of a grain of rice) utilized as an abrasive to eliminate coating on surfaces without causing damage the surface itself by blasting the rice size pellets through a blasting lance. This is prominent 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.

Calling CO2 a super-gas may be overstepping the bounds of the definition, but it is certainly the most versatile element available in the industrial gas market.

To find out more about how you can be supplied with carbon dioxide in Southern California for any of your specialty gas operations, call WestAir Specialty Gases and Equipment at 866-WESTAIR or at info@westairgases.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 led teams of engineers and technicians as an R & D manager for major gas companies. His work lead him to running the marketing efforts of technology worldwide industrial gas suppliers. He now consults to the industry on the business specializing in operations, applications and marketing.