Carbon dioxide (CO2) applied in the food and beverage industries is among the major consuming sectors of the merchant industry. In the developed markets, such as the US, Europe, and Japan, the application in food processing and preservation often holds a prominent place among merchant usage in many regions and markets.
In the US for example, food and beverage applications, on average account for around 70% of the total demand in the merchant markets. Such processors purchase product as a liquid, for applications in cryogenic freezers, atmospheric modification in packaging operations, snow generation, and dry ice extrusion on site.
In many developing world markets, beverage carbonation is the predominant demand for the product. In some cases in developing markets, CO2 is generated from a combustion plant, which uses fuels such as diesel or natural gas for generation of the product, recovered via a small MEA (momoethanolamine) plant, and purified downstream for use in carbonation of the beverages in a captive operation.
Over the years, usage of CO2 for food processing applications has grown significantly, while the machines needed for such applications have often been the basic requirement for usage. The hardware can be very simple, from snow horns, and valves, to more complicated cryogenic freezers. Various configurations of freezers and apparatus have been developed, and some discarded, with a quest for greater flexibility, convenience, and efficiency, coupled with more sophisticated operating capabilities.
The need for purity
Soft drink applications for CO2 date back to some of the earliest usage, when the appeal of carbonated patent beverages were developed, such as Coca Cola.
In the case of beverage carbonation, for the most part CO2 is delivered as a liquid product to the manufacturing plant. The product is vaporized, and applied within the beverage making process.
Since a number of contamination cases have occurred over the years, the soft drink companies, in particular, have become very keen on absolute assurance of quality, and testing of product. This is in addition to modern CO2 plants working to assure ongoing quality. Soft drink specifications are strongly applied to most producers, largely driven by the major soft drink producers such as Coca Cola, and Pepsi.
CO2 quality standards are defined by the ISBT (International society of Beverage Technologists), the CGA (Compressed Gas Association), the EIGA (European Industrial Gases Association), and the FDA (Food and Drug Administration). The minimal CO2 content stated by the ISBT and the CGA, call for 99.9%. Further the presence of water, volatile/non -volatile residues, oxygen, nitrogen, carbonyl sulfide, NOX, SOX, and numerous additional constituents are strictly limited, in order to meet such standards.
As to the food industry, there are standards which are sometimes written by large customers, such as Tyson Foods; however, official standards for quality are defined by the CGA, and FCC (Food Chemicals Codex), for example. With these two associations, minimal CO2 content is generally defined between 99 – 99.5%. Other constituents are limited, however not as strictly written as the beverage sector.
“Soft drink applications for CO2 date back to some of the earliest usage, when the appeal of carbonated patent beverages were developed, such as Coca-Cola”
Quality standards and testing are very ridged for the beverage industry, while food processors which consume CO2 have less of a quality and testing demand, however, both sectors need to be vigilant of a quality product which will be consumed.
Applications in the food sector
Relatively speaking, the food sector probably dominates usage in the merchant markets for developed regions of the world. In the US for example, about 70% of liquid is sold to the food and beverage sector; of which about 40- 50% of is the food processing sector. Some markets, such as the US Midwest may have higher food processing usage, due to a large number of big meat related processors, such as Tyson, Cargill, JBS, and Smithfield Foods. Most of the CO2 product delivered to the processors is in bulk liquid delivered over the road (some rail is used to deliver to depot operations to supplement this demand).
Dry ice is significant in these food processing markets, which is often sought for grinding, blending, and shipping purposes. As to the shipment of food products which use dry ice, this often represents whole or portioned poultry, and portioned meat products as well. Dry ice snow is a significant factor in such processing and maintaining cold shipments, which is generated from stored liquid on site. The snow can be used in places such as blending, chopping, and shipping, as would dry ice rice pellets. Such installations include snow applicators mounted for use in conveyors for boxed/container-based meat and poultry products, and installations in blending machines, often mounted on the top or sides of these devices.
A significant amount of CO2 is applied in cryogenic freezers, which exist in a number of configurations. Such configurations include single and multiple pass tunnel freezers, spiral and batch freezers. The product is delivered to these machines via insulated copper or stainless piping, where these machines use settings for residence time/belt speed, and temperature. There are also applications in various packaged food products for a gaseous product, in atmospheric modification – sometimes blended with other gases. Another food-related application is the development of CO2-based supermarket refrigeration, which is rather common in Europe, and which has potential in select US markets as well. The use of various cryogenic freezers probably has dominated the application for CO2 in food processing, however snow and dry ice pellets tend to be used more over time, as I have found in recent years.
Specific applications in some markets have consumed large tonnage, such as dry ice snow packed into bunkers within rail cars, for maintaining the frozen state of French fries and other vegetable products. This has been a niche market in the US Northwest and in more recent years has moved to Canada.
Beyond the above applications for CO2 in food industry, would be agricultural applications for CO2, more specifically crop growth enhancement for crops including beefsteak tomatoes. As to CO2 for crop growth enhancement, over the years, this has been fulfilled via flue gas v. merchant product. In some markets, another food-related application is usage in grain fumigation, which has benefits over other substances, including proprietary chemical agents. In this case, there is no residue left behind as with many of the alternate fumigation agents.
In summary, the lion’s share of CO2 in the food sector is applied via various freezers, snow applications, and dry ice.
An ongoing challenge in the food processing plant is proper ventilation, representing sufficient exhaust capabilities of spent vapors generated by the application of CO2. One of the most important subjects to be keenly aware of is proper ventilation, and for current and future installations, particularly in a closed environment, be sure there is adequate removal of CO2 vapor. Lives and good working conditions depend upon this.
Another challenge which has always been present, is the pushback against an alternate cryogen, that being nitrogen. Further, mechanical refrigeration has become more efficient in some places; however on the positive side for CO2 use, is the expansion into more applications, such as CO2 supermarket refrigeration in some climates. Since much of the laid in cost of CO2 is driven by distribution expenses, nitrogen can be a viable competitor, or too expensive v. CO2, at least in some food applications, particularly cryogenic freezing. Some years ago, it was a standard for large food companies such as McDonald’s to have contract manufacturers freeze with nitrogen. CO2 in such a case had a place in blenders/mixers, as CO2 snow. Sometimes, the customer seems to be married to one gas or the other, or maybe to cryogenic freezing.
Despite alternate refrigeration methods, simply put, given the physical characteristics of CO2, other refrigerants or agents cannot be used in some applications, such as in CO2 snow and dry ice production. Further, as an excellent component of food processing, CO2 sublimates from a solid to a vapor, and exists in solid form, as a snow product, which is excellent in blending, mixing, and shipping use. Nitrogen cannot replace these uses. There will always be a pushback against CO2 in the food processing sector, with other refrigerants. Therefore, this is a significant ongoing challenge.
“…the lion’s share of CO2 in the food sector is applied via various freezers, snow applications, and dry ice.”
As to future opportunities and developments, we can expect more efficiencies and developments to be applied to the hardware used in the food industry for CO2, including digital and remote controls; making for more convenience, and likely more automation into the future – when considering the possibilities of AI, and more online integration.
As to some of the current concerns, the trade war and tariffs on US crops and ethanol exports is only damaging the agricultural economy and associated industries. Further, all of the factors are weighing down on the ethanol industry, including tariffs, high inventories, and the flooding in the Midwest, with reduced planting of corn, may precipitate tight inventories and limited source opportunities for fermentation-based CO2 supplies. Given the domestic CO2 industry is supplied heavily by the ethanol sector, around 40% of the total supply, the wellbeing of the ethanol producers is very important.
It is felt that many of the CO2 sources from other by-product streams and natural sources are already well committed. Therefore, the development of more source types could be the long-term strategy and answer for further diversification among supply types. Large emitters of CO2 are flue gas and biogas. Both have significant problems, the first, as flue gas is too expensive to compete with other source types, where the lean CO2 content requires recovery upstream of liquefaction/purification, usually by a solvent, such as MEA. Then, on the biogas front, the sources from waste product often incorporate fecal matter – which physically and chemically can be removed to meet purity standards.
However, it is the perception that makes it impossible to imagine such waste matter from cattle, for example, is going into our processed food and beverage products. This latter possible source type may never be commercialized due to the perception issue, which, at present cannot be reconciled.
As for the gas companies, I recommend they take another look at all food related applications for CO2 in the markets served; this leads to expanding the use of the product, and often solving problems and challenges which the processor has – all of which leading to greater sales and customer satisfaction.
The CO2 industry in service of food processing is an interesting and challenging part of the industry, which is a major consumer of product among market types for most regions served in the US and elsewhere.
About the author
Sam A. Rushing is President of Advanced Cryogenics, Ltd, and a chemist, with extensive merchant and consulting experience. Advanced Cryogenics provides work covering all subjects, from technical thru markets. The company also supplies new and used CO2 equipment to any project type.
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