CO2 in Industry: Organic and Inorganic Applications

By Sam A. Rushing, president, Advanced Cryogenics, Ltd
Special to The Digest

Carbon dioxide has been on the forefront of much of today’s media as a major greenhouse gas which will be an extraordinary challenge to manage in the future. The greenhouse effect, that being rise in global temperatures, sea levels, and other catastrophic effects are one of the most daunting challenges ahead – even though so many schemes for sequestration have been identified, but yet are to be proven.

This article is specifically written on the subject of CO2 industrial applications, primarily relating to organic and inorganic chemical usage in industry. This chemical industry application, which can include chemical feedstock applications for CO2 are a smaller part of the greater applications in the merchant trade. As I have written in the past, in the developed markets some 70% of the merchant CO2 is dedicated to food and beverage usage, for the most part, in such markets. The remaining 30% is then dedicated to a wide range of industrial applications, including chemical manufacturing, both organic and inorganic feedstock requirements for carbon dioxide. Of course, there can be niche, pipeline fed destinations for carbon dioxide which are ‘over the fence’, via a more distant pipeline; or which (in part) create a base load for a plant location.

CAPTIVE UTILIZATION OF CARBON DIOXIDE IN SPECIFIC COMMODITY CHEMICAL MANUFACTURING PROCESSES

I think of many applications for CO2 in industry to include both inorganic and organic in some fashion or form; beyond the large volumes and wide variety in the food processing industry (freezing, cooling, and gas packaging), and of course beverage carbonation. When taking out welding metallurgical and allied applications, plus fire abatement, supercritical extraction, oil and gas enhanced production and stimulation, carbonic acid production for Ph reduction, laser applications; and pneumatic applications, the following paragraphs describe what I generally think in terms of organic and inorganic related applications for CO2.

From a commodity chemical industry perspective, soda ash or sodium carbonate plants such as Church & Dwight and Solvay in Green River Wyoming, for example, use CO2 from a merchant Green River, WY plant in the production of sodium bicarbonate or baking soda. The Church & Dwight plant has been supplied via Linde’s pipeline from their merchant CO2  facility. Other similar plants are using CO2 for sodium bicarbonate production in Old Fort, OH; which uses truck and rail deliveries. Since much of this sodium bicarbonate must meet certain food /pharmaceutical applications, a food grade, refined CO2 is used, v. using a raw gas product without purification. CO2 has applications elsewhere in the production of various commodity products in industry.

As to commodity organic chemical products, there are a couple of examples. Methanol production can be enhanced by CO2 injection; whereby CO2 can be injected into a syngas (from reformed natural gas and via catalytic reaction) yield an increased volume of crude methanol. If delivering CO2 via pipeline to such a methanol process, this can be a captive market as well. Other possible captive markets include the production of urea; whereby the conventional urea manufacturing operation is within an anhydrous ammonia production operation. The CO2 by-product from anhydrous ammonia production is then used in a two-step process which would yield the intermediate ammonium carbamate; and then dehydrated to a commercial urea. In some cases, if the anhydrous ammonia plant is not available with the by-product CO2 as a feedstock for urea production on site; then in a number of locations anhydrous ammonia is delivered to a site where CO2 is combined for the production of urea; this is another possible captive application, if large enough, and if delivered via pipeline or other means.

APPLICATIONS IN THE ORGANIC AND INORGANIC REALM OF CHEMISTRY AND MATERIALS / SUBJECTS TREATED WITH CO2

Further with respect to organic – related applications for CO2, would include the application of raw material for sugar production including polysaccharides – i.e. starch; and a wide variety of organic compounds for plant growth and their development – of course including urea, once again, for example. In terms of a solvent in industry, the application in dry cleaning operation thus replacing perc is an interesting and environmentally friendly application, moreover, replacing and eliminating VOC emissions from an old standard in the form of organic perchloroethylene. Also, there is the application for CO2 as a solvent for many lipophilic organic compounds, and can be used for removal of caffeine from coffee. In the pharmaceutical and chemical processing industries, CO2 is being more readily accepted these days as a less toxic option to more traditional solvents such as organochlorides – which can be similar to the replacement of perchloroethylene in the dry cleaning industry. In the case of certain chemical process and all pharmaceutical industries, the USP standards may be required v. simply food grade product. In the case of USP quality, the major gas companies have a few strategic plants reserved for the purpose of fulfilling this USP demand, essentially tight record – keeping of the production process is the bottom line in USP grade. In terms of agriculture and biological applications, this could be considered organic in general terms, since the plant and animal life is organic by definition in terms of composition. Plants require CO2 for photosynthesis, and in greenhouse settings, CO2 is often used as a product of fossil fuel combustion, or via merchant product in a gaseous form injected into the greenhouse to enhance growth and quality of the bedding plant, flowers, vegetables, and cannabis production, for example. Further, when raising the concentration above 10,000 ppm for a period of time, certain insect pests would be eliminated in the greenhouse. This can further address the application of CO2 as an application in grain storage bins, ships, and elevators for insect control thus replacing toxic alternatives in this fumigation process. Some of these fumigation alternatives to CO2 are of a halogenated organic composition.

Algae has been one of the possible solutions as a raw material for biodiesel production or possibly fermentation. Today, the need to sequester CO2 from power plants is being evaluated via the application in ponds for production of algae. Algae production may benefit from the application in larger commercial settings, again in the biodiesel market; either as a carbon sink or CO2 as a feedstock for production of an organic – based algae. There is good potential in this area.

Diagram 1: CO2 microalgae cycle

In medicine, a USP grade CO2 has often been used as a respiratory stimulant – more specifically up to 5% is added to pure oxygen for breathing stimulation.

SUMMARY

As you can see with the above definitions of some CO2 applications in industry, health, and even sequestration, there is a wide range of both organic, and inorganic – related applications for this most versatile product. As the demand for sequestration and more environmentally friendly agents develop, more CO2 will be found in industry. As noted in this article, sequestration in an organic sense, could include applications as an agent for certain algae production options; potentially considered for biodiesel production – and this algae can again be a possible feedstock for fermentation as well; thus a loop system of sorts (please see diagram 1, showing a possible loop system for CO2 in the production of algae oil, biomass and oxygen, as an example).

Then, again in terms of environmentally friendly applications, this can be found  in cases such as replacement of organic halogenated solvents in dry cleaning; plus many more examples. Once again, CO2 is a remarkably effective and versatile chemical; and is again a most daunting greenhouse gas which must be addressed in the term ahead, with respect to global warming and greenhouse gas concerns worldwide.

About the author:

Sam A. Rushing is a chemist and president of Advanced Cryogenics, Ltd., an international cryogenic gas consulting firm, with emphasis on carbon dioxide challenges. The company offers a full menu of services from technical, market related; production and process evaluations, as well as applications and business development services. Please contact the author at rushing@terranova.net , telephone 305 852 2597; www.CO2consultant.us