Carbon DIoxide, CO2, or Super-Gas?

Butler Gas Products is a trusted supplier of carbon dioxide to Pittsburgh and surrounding areas.

The majority of people not affiliated with the industrial gas industry are familiar with 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

In the early 1600’s, Jan Baptista von Helmont, a Finnish scientist, discovered CO2 as the gas that resulted from burning wood. In the mid 1700’s Joseph Priestly, an English chemist, discovered that the combination of water and CO2 being dispensed from a fermentation process generated sparkling water which changed the taste of water and initiated the start of the soft drink industry.

One of the characteristics of the gas that was discovered was its ability to be easily 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 offered and employed in all three of its phases – gas, liquid and solid.

Gas

For those involved in the gas industry, CO2 is most commonly associated as a refrigerant in the food and beverage industry and as a shielding gas in welding. 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 a very powerful acid, it is an acid nonetheless and has the ability to regulate the pH in certain applications where the pH is an important system parameter. This is prominent 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 requires 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 surrounding temperature. The result is that any application using liquid CO2 must be under pressure. Those involved 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 sent 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 prominent is fracking. In this case a propant is pushed into rocks rich with oil with the use of man-made devices. 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 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 special high pressure washer, liquid CO2 is used with a stain remover. The clothes are then washed regularly employing 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 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 properties and is reached through modification of temperature and pressure; this is referred to as the supercritical state. The supercritical state of CO2 can be created in a specifically designed processor. Because it is an excellent solvent, CO2 in its fluid phase 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 applied in a wide variety of methods as a coolant. When liquid CO2 is transported through a high pressure line and released using special nozzles, it right away transforms into CO2 snow and is applied in food refrigeration and freezing. Dry ice pellets replace regular ice in tubs that hold perishables for long over-the-road transport.

Extremely small pieces of dry ice are (about the size of a grain of rice) used as an abrasive to remove coatings from surfaces without damaging the surface itself by launching the rice size pellets through a blasting lance. This is prevalent 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. This is also advantageous because is that there is no need to separate the removed coating from the abrasive as the pellets sublimate to CO2 gas leaving the residue particles for easy cleanup.

Labeling CO2 as a super-gas may be controversial, but it is without a doubt the most versatile gas available in the industrial gas market.

For more information on how you can be supplied with carbon dioxide in Pittsburgh for any of your specialty gas operations, call Butler Gas Products at (412) 771-7660 or at customersatisfaction@butlergas.com.

John Segura, PE

About the Author

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