CO2 today: A versatile chemical with growing industrial applications

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

The average person on the street often would see CO2 today as an agent for beverage carbonation, a gaseous agent in the atmosphere which is a normal part of many biological processes; plus today it is now viewed strongly as a major greenhouse gas.

In reality, this is just starting to scratch the surface of what this product represents, whether this be something viewed some years ago; today and tomorrow. CO2 is a versatile gas and chemical agent used in many phases of manufacturing, well beyond beverage carbonation. This includes carbonic acid formation for PH reduction, cryogenic freezing, cooling; and packaged food atmosphere modification. Also, there would be uses for pest control, environmentally friendly cleaning alternatives, solvent applications in many forms of industry, agricultural applications, and the enhanced production of oil and gas; all of which to name a few of the growing list of uses for this versatile product.

The successful and long term application in industry is driven by strategic availability, as driven by raw feedstock availability; as well as time tested and well liked applications v. alternate forms of achieving a similar end. Such alternate means can often be environmentally unfriendly, hazardous, or more expensive than CO2 applications in industry.

REGION SENSITIVE TO PRODUCT AVAILABILITY AND COST EFFECTIVE APPLICATIONS IN THE MERCHANT SECTOR

In terms of strategic supply of CO2, and the nature of today’s CO2 markets, in most developed world regions, such as North America, Japan, and Western Europe, the variety of applications for merchant CO2 is roughly summarized in the table below. Also as shown, in the developing world markets, at least for the moment, quite a different story is shown.

With respect to the distribution – sensitive nature of CO2, as with most other gases, when selling as a truck delivered bulk product, this would usually be sold within an approximate 150 – 250 (maximum) mile radius of the production plant, or the point of origin. As to rail shipments, this distance can sometimes be an extraordinarily long journey, however, generally substantially longer than via trucking. With diesel fuel and gasoline on the rise today, selling prices for CO2 are of course higher, often via fuel surcharges being added to the invoices. As for the rail system in the United States, many major railroads are either overwhelmed with current freight commitments, some of which are either a feedstock for, or a finished product from the growing ethanol industry. The railroads are also sometimes highly inefficient, thus producing unreliable availability of CO2.

If the expansion of ethanol continues to grow, either as an oxygenate alternative, or simply as a ‘biomass’ related form of energy v. fossil fuel based energy products; it will become ever more important to construct ethanol and of course more strategically viable CO2 plants within or closer to markets which are currently being served from long distance sources.

As to long distance sources, this has historically been achieved via railroad deliveries to depot locations, or in a few cases, direct to the customer’s consuming location. On the other hand, with the cost of fuel rising, and the railroads turning away business, more strategically located CO2 sourcing will become more and more essential, if at all possible. Some of this is being planned with new ethanol plants, however, progress is slow, and the majority of ethanol plants which are discussed initially never achieve financing; therefore, are never constructed.

DEVELOPING WORLD MARKETS – FACTS AND CHALLENGES AHEAD FOR CO2 SUPPLY AND SOURCING

As is shown in table 1 above, the lion’s share of CO2 is being consumed in the beverage industry; soft drinks, beer, and fountain beverage gas service. The balance can sometimes be small food related applications; and or a small presence of industrial usage. Industrial, as noted above, is often in the form of packaged cylinder gas.

With respect to the value or selling price for CO2 in many developing countries, this selling price, when delivered in bulk, can often start at and range well beyond USD $200/ton. The tonnage is often relatively small when comparing with CO2 consumption by much larger plants found in the developed world.

Historically, many developing world markets without available substantial raw traditional forms of feedstock, such as from sizable reformer, ammonia, or fermentation plants, would use CO2 combustion plans on site, or via certain gas companies. This, simply put, is combustion of coal, coke, fuel oil, natural gas, etc, recovering (concentrating) CO2 via usually an MEA solvent process; and then liquefying and purifying to meet beverage standards. The cost of doing so is often from $150 to $300/ton; which would fit the economic standards for pricing CO2, as mentioned above, often $200 per ton and more. These plants are sometimes disappearing in favor of new larger modern plants with enriched by-product CO2, which commonly serve developed markets. Such an example would be in the Middle East, where small combustion plants have commonly served individual beverage facilities for their CO2 needs; or certain resellers have operated these combustion plants as well for high priced CO2 markets. Today, with interest in enhanced oil recovery, gas well stimulation; and more of the traditional non-beverage applications, these developing regions are evaluating and sometimes building CO2 plants sourced from a concentrated and traditional form of feedstock. The end result, assuming the plant is sufficiently sized, and well loaded, can mean much lower costs for production of an industrial or beverage grade product.

If such concentrated viable feedstock is available in the developing world markets, the challenge is to place this product into industry which has often never used CO2 to achieve various tasks, such as refrigeration, insect control, or PH reduction; for example. Often the markets are there, but require development from ground zero, over and above the beverage and cylinder gas interests already in place; this takes time and is sufficiently challenging.

CO2 APPLICATIONS FOUND IN THE DEVELOPED WORLD – DELIVERED VIA TRUCK AND RAIL

REFRIGERATION AND FOOD PROCESSING

I have offered an approximate percentage of CO2 found in average developed world markets being consumed by various sectors of the food industry. More specifically, a significant percentage of this application would be found in cryogenic freezing applications. Cryogenic freezing machines are often offered by specific gas companies to complement or sell their CO2. Such machines are also available from a variety of surplus suppliers, or from new suppliers, who are not owned or affiliated with the gas concerns. With respect to this application of CO2, in some regions, this would account for perhaps most of this approximate 40% volume for the merchant markets. In terms of cryogenic freezing, simply put, CO2 liquid is stored, and then piped to the freezers, often multiple pass, single pass, or a spiral –configuration. The freezer often operates at -60 degrees F, and sometimes the cryogenic freezer is used alone to lower temperatures of food products, or used to partially refrigerate a product pre or post mechanical refrigeration. Attempts to boost the refrigeration capabilities for CO2 in cryogenic freezing has included mechanical refrigeration of the liquid CO2 prior to entering the cryogenic freezer, hoping for greater BTU removal capabilities than without such treatment; and so-called ‘cryo mechanical’ freezers have also been attempted; however, the end result, as to the benefits and costs when analyzed are difficult to interpret. I think these mechanical hybrid operations can tend to sometimes cost more in capital and operating overhead than strictly running an efficient CO2 cryogenic operation. Frozen entrees, individually quick frozen (IQF) food items for subsequent packaging, and ground, mixed beef are common in this application of CO2.

Other applications in the food industry would include producing a CO2 snow for grinding and blending of meat and other food products; plus often a mixture of gases including CO2, or pure CO2 is used in packaging applications; meaning modifying the atmosphere which surrounds the food product inside the package. The packaged cheese business is an example of this.

BEVERAGE APPLICATIONS

The application for CO2 in carbonation of soft drinks and use of fountain beverage CO2 are commonplace, and perhaps 30% of the total market in the developed world; and in the developing world, up to 80-90%. Carbonation of beverages is common in all world markets. In the developing world case, there is simply no substitute for CO2 use as a carbonation agent, so the expensive combustion plants are often the only form of sourcing, since little or no other markets presently exist.

The beverage industry has continuously created greater stringency for purity, handling, and production of CO2; somewhat due to claims of CO2 contamination by the major soft drink beverage firms in Europe and The United States. These claims include various source types for CO2; which has resulted in a careful watch of the make up for the raw gas, as well as continuous and often testing every load of delivered product to the soft drink beverage plant site. When meeting this level (ISBT standard) of CO2 purity, this will usually meet or exceed all other specifications for CO2 purity, short of USP standards sought for a very small medical market. The beverage industry growth is often consistent with population fluctuations; but is often offset by bottled water sales. In the end, this market may be experiencing a flat to modest (1-3%/year) growth rate up until the last few years, but will always be essential as long as certain beverages are being produced. In certain beer producing plants, CO2 can be used for supplemental carbonation, as would be champagne; or in some large U.S. breweries, the merchant CO2 is simply used as a back – pressure agent in the brewing process, sometimes never touching the actual beer being produced. The specific point of application can vary somewhat in this overall beverage market; however, the general use of CO2 for beverages will always be required.

There was essentially a stagnant market for beverage carbonation among the well established and store brands for some years; however a resurgence occurred with the specialty beer and alcohol spiked carbonated waters over the last few years; perhaps now a 3% – 4% growth market in the developed world.

INDUSTRIAL APPLICATIONS  

     – ACID REPLACEMENT/pH reduction

Within a range of pressure and temperature, CO2 in water can yield carbonic acid. Carbonic acid is a relatively weak acid, which is self-limiting at a moderate pH. By-products are generally benign carbonates and bicarbonates v. sulfates as found when using sulfuric acid. The CO2 industry can claim safety in the application of this product v. sulfuric acid mishandling, leaking, or splashing. Common applications for many years in the US have been in water treatment plants, often affiliated with hard water and lime treatment. CO2 applications in municipal water treatment plants once originated via submerged or underground burners, generally combustion of natural gas, and the flue gas containing CO2 was the old fashioned form of making CO2 available to these plants. Today, many of these combustion systems have been replaced by a CO2 liquid storage, vaporizer, and diffuser system; as would be the modern water treatment plants. This application has been tested, and sometimes applied in power plant environments, and in environments where lower pH levels are sought, and the advantages of CO2 is well understood, and is competitive in price.

• INSECT/PEST CONTROL

In select markets, particularly in year round warmer, humid environments CO2 has successfully replaced some of the long used halogenated hydrocarbon products, and other agents, which can have long term toxic or even carcinogenic effects upon humans and animals. This application has been used in grain storage facilities at large. Reference has been made to devices which trap mice and rats, subsequently asphyxiating these pests; this may become a growing market as well.

• GAS WELL STIMULATION AGENT

Many of the natural gas fields have successfully chosen the use of CO2 v. other agents such as nitrogen, and non – gaseous products for well stimulation, often referred to in generic terms as ‘frac’ service. In short, under sufficient pressure, fracturing occurs thus releasing greater natural gas in the production process; plus the effects of carbonic acid can have a desired effect upon select geological compositions, and can also reduce swelling of clay in the formations. In some US & Canadian regions, such as the US Rockies, southwest, west, and Saskatchewan /Alberta; this market can amount to thousands of tons per day in volume, with often strong pricing, when booster pump rental, pumping fees, and related.

• SOLVENT APPLICATIONS

This is a growing sector of the CO2 market, ranging from dry cleaning solvent applications in specific dry cleaning machines which operate under pressure, as well as closed system applications for extraction of essential oils, etc. CO2 is being tested in a range of other applications for use as a solvent replacement, which would be safer than what would be found, for example, with dry cleaning, currently perchlorethylene, or ‘perc’. As with CO2 use for replacing sulfuric acid, many of the solvent applications replace agents which are deemed carcinogenic, or are being banned from release into the atmosphere, such as VOC materials in dry cleaning operations.

    –  CARBON DIOXIDED USE IN CATTLE & BIRD STUNNING OPERATIONS

For many years, CO2 has been used to stun cattle and birds prior to slaughter. This is the humane method of preparing such animals for processing; and will probably grow as the food industry grows.

            –  FIRE ABATEMENT, WELDING APPLICATIONS, FOUNDRY &

               METALLURGICAL PLANTS

Fire abatement is a common application for CO2, as would be the application in welding gas mixtures. Some foundries have commonly used CO2, as have large steel mills for specific applications.

• GREENHOUSE ENRICHMENT APPLICATIONS & OTHER AG USE

In lieu of burning natural gas for flue borne CO2, merchant CO2 has been used in a variety of greenhouse environments for plant growth enrichment programs. CO2 has been tested for enhanced crop growth usage in irrigation projects; with some successful results. Commercial algae plants often require CO2 as well. The sum total of these agricultural applications can be significant in some markets. Cannabis growth enhancement represents a growth market, given this is a premium priced commodity.

• ENHANCED COALBED RECOVERY OF NATURAL GAS

As the thirst for natural gas grows, and as enhanced recovery methods are used, CO2 has been studied and tested for use in coal bed methane (recovery) applications. In short, CO2 molecules would replace methane in this application. These applications have been tested and evaluated in regions such as Alberta and The US west.

• DRY ICE

Dry ice is a form of CO2 pressed into blocks, extruded into various forms and sizes, often called ‘pellets’ or ‘rice’ dry ice; and often simply flashed from liquid under pressure to atmospheric pressure, thus producing CO2 snow and vapor in the process. The applications for dry ice are wide, often of a refrigeration nature, in food processing, preservation, and shipping applications; as well as industrial applications of a wide nature. One application which has gained favor is so-called ‘blast cleaning’, using dry ice (rice configuration) product for blast cleaning, paint removal, and related, which replace the use of various hazardous solvents, steam, sand, etc. This is a growing application in the industry, and should continue this way. Dry ice, when produced in a commercial setting, should have vapor recovery (for return and compression/liquefaction) in order to yield a reasonably profitable manufacturing operation. Dry ice is a unique product, and has a wide base of applications.

• CHEMICAL FEEDSTOCK USE

Whether this is a captive application for production of methanol, urea, or sodium bicarbonate, for example; or use of this product for a wide variety of chemical feedstock or agents for chemical precipitation; the base is wide for CO2 use, as well as the volume ranging from mega sized to very small.

ENHANCED OIL RECOVERY

CO2 is a common agent for enhanced oil recovery (EOR), which is a tried and true agent in this ever growing application; again as with natural gas, sought highly as the thirst for petroleum grows. CO2 in some US markets, such as Mississippi and the US west and southwest often use natural underground wells as a feedstock for this type of service, already often under high pressure. If the source is from a low pressure by-product source, such as reformer, fermentation, and ammonia, for example, this low pressure by-product from the source plant is usually between atmospheric and 15 psi. The application for EOR requires high pressure and pipeline operations, thus a sufficient capital investment, particularly if not sourced from an already high pressure natural source. For example, the pipeline capacity for one particular plant, located in Beulah, ND, that being Dakota Gasification, is about 10,000 tons per day. EOR demands in Saskatchewan have been growing in volume to fulfill this total pipeline capacity, traveling from North Dakota into Saskatchewan for EOR projects owned by EnCana and Apache. The natural high pressure sources serving the Texas Permian Basin; plus further regional operations are much greater in volume than this Dakota operation. This speaks of the magnitude, or potential magnitude. I know that oil producing regions outside of the United States, which were never EOR candidates are now approaching or evaluating such mammoth projects. Many such projects are being considered from all source types for fulfillment of EOR options; as the ever growing thirst for oil grows.

SUMMARY

The above mentioned applications for CO2 include a food/beverage nature and industrial applications which represent the ever – growing use for CO2 in industry at large, or the so-called merchant market demands for the product. As we can see, some environmentally friendly forms of CO2 from blast cleaning, to acid replacement, to solvent replacement exist, and will continue to grow. The industry will continue to develop and expand in new and existing sectors of industry. The product is one of the most versatile gases and chemical agents found in industry today.

About the Author

Sam A. Rushing is a chemist, with well over 30 years in the industry, with both merchant and consulting expertise, who handles all phases of CO2 consulting assignments, from business, and market related to process, and applications related work.

Tel 305 852 2597

rushing@terranova.net  www.carbondioxideconsultants.com