With our magazine this month focusing on the non-ferrous metals sector and once again adopting an African theme, we examine the African CO2 links and merchant market. In addition, we also explore in greater depth the CO2 supply in the US from ethanol projects.

CO2 in non-ferrous metals & the merchant market
The carbon dioxide (CO2) industry is a minor supplier to the metals industry at large; which is not specific to the non ferrous metals.

With respect to the metals industry at large today, perhaps the most abundant and greatest amount of industry growth is via blast cleaning with (rice) dry ice. Otherwise, over the years CO2 has been a rather common gas in welding applications, via gas mix products.

The CO2 industry, over the years, has been a minor supplier to foundries, typically in applications such as cooling silicon-based moulds, for example. Plus in some large steel mills, CO2 has played a key role as a stirring agent in large quantities.

These metals-related sectors of the CO2 industry have been a part of the so-called industrial sector, often via cylinder gas packaged product; which in the grand scheme of things is quite small in terms of merchant market usage.

Of an estimated 20-30% of a mature CO2 market, in the developed economies, metals related applications may account for perhaps one third of this industrial sector in many of these markets.

On the other hand, in the developing world where CO2 is often derived from expensive combustion sources compared to cheaper by-product chemical, natural, and energy projects, cylinder gas in the welding trade can be a fairly significant factor.

However, in the greater scheme of things, such developing markets are primarily beverage carbonation, and cylinder gas (fountain beverage and welding applications). Hence in this world, it is more significant by volume compared with the developed world.

As for Africa, short of the more developed regions such as South Africa, where a myriad of applications exist from traditional concentrated CO2 sources, a greater balance of the region is highly beverage carbonation and cylinder gas.

Some exceptions, such as South Africa, may contain a number of traditional sources.

Traditional sources are shown as a percentage of supply in the typical developed world.
I want to direct this article to the subject of ethanol, and the evolution of the ethanol industry at large. This evolving ethanol industry has received strong criticism when using a food-based product such as corn for fermentation rather than ‘supplying food to hungry nations’.

Today, with the new administration and even without this change in US politics, there must be a drive for energy independence, in part from agriculturally borne feedstocks; which can include algae, a wide range of the so-called cellulostic agents, including corn stover (left over leaves and stocks of corn).

The future is ultimately bright for ethanol and biofuels, which generally yield a CO2 off-gas suitable for merchant use, when readily refined; and is excellent for captive use in CBM and EOR projects, for example.

The greatest hurdle today, as we all know too well, is the capital crunch, and banking disaster.

When this turns around, much of the ethanol industry will be more readily focused to proceed ahead with more energy efficient, non food-based feedstock projects, and the traditional corn and food-based grains used in fermentation; with processes and energy efficient improvements in great numbers. We must look ahead, however.

CO2 from ethanol sourcing
CO2 has unique properties, one being sublimation from a solid as dry ice at atmospheric pressure; thus creating the ‘fog effect’. However, under a variance of pressures, carbon dioxide is a liquid.

Liquid CO2 is the product which is stored at the production plant site, as well as at the customer’s site and CO2 is hauled via tanker trucks, rail cars, or barges under pressure, as a liquid material.

Raw CO2 from fermentation processes is a saturated gas, at low to atmospheric pressure when leaving the ethanol plant. From this point forward, CO2 is either vented to the atmosphere, sequestered in some state, or liquefied and purified for the merchant markets.

The lion’s share of ethanol which is recovered is generally directed to the merchant markets; in North America, perhaps some tonnage will go to the service of enhanced oil recovery in the term ahead.

Ethanol is a high-octane fuel which is used primarily as a gasoline additive and extender.

CO2 is a by-product of fermentation processes; hence the growth in this industry at large is of major interest for all carbon dioxide markets and environmental projects.

This demand is strong in the US, Latin America, Europe, and regions of Asia, to name major consuming markets. In terms of the 2007 global production of ethanol, this was about 35 billion gallons per year.

Corn-based ethanol accounts for 97% of the entire ethanol market in the US, while Latin America produces ethanol primarily from sugarcane and molasses. Ambitious plans for ethanol now exist in the Philippines, with mandated blends on the rise.

Over the last few years, literally hundreds upon hundreds, if not a thousand or more ethanol projects have been announced globally.

As for this sector, the merchant markets can be well served if strategic availability should fit the markets served.

In the US, for example, about 30% of the CO2 plants for merchant service are sourced from by-product of ethanol. If we consider the usual corn-based (sometimes wheat) in the US, for example, the new plants are based upon continuous fermentation, dry mill operations.

The scale of ethanol economics and plant size has grown to a usual 50-100 million gallons per year (GPY), which represent over 400-800 tons per day (tpd) in CO2 raw gas.

The CO2 is low pressure when vented from the ethanol plant, and the CO2 facilities now can range, with storage, civil work, building storage, and scales; turn key basis, $11m for the 400 tpd plan and $17m for the 800 tpd plant. Numerous new CO2 plants of the larger world scale size are slated for the US today; and more to come, all from ethanol.

The fastest growing sector for the merchant trade has been CO2 sourcing from ethanol by-product, while a few sources develop now and then from natural wells and reformer operations generally speaking, with ammonia as a US by-product source on the decline.

Therefore, developments relative to ethanol projects, both from the traditional corn and wheat-based (first generation) fermentation; and to be expected over the next few years, as technologies are refined and efficiencies are improved upon the cellulostic ethanol sources, such as switch grass, wood chips, and other organic matter.

When CO2 has been discussed as a source from landfill operations, there is no realistic merchant market for this product, other than oil and gas, and perhaps coal bed methane projects.

The consumer is absolutely turned-off when the term ‘waste’ is used in feedstock definitions, as well as the ISBT and the major food and beverage firms, despite chemical purity, when sampling CO2.

On the cellulose-based front, proprietary technologies include concentrated acid hydrolysis, enzyme conversion technologies, and syngas processes claimed to yield an affordable and commercially sized ethanol process and fuel grade product.

In reality, much of this is in the pilot or demo phase; but at least one such cellulostic plant has been announced for Georgia, using Department of Energy (DOE) grants to the sum of $50m for the first 20MM GPY phase of the plant and the second phase will receive a $26m grant as well.

It was said to be operational in 2008, however by scale, at least the first phase was too small in scale for a viable CO2 plant, by most standards. Numerous additional ethanol plants using feedstock from sugarcane, citrus fruit waste including the fruit peel, sweet sorghum, and cellulose-based materials are found in locations such as California, Florida, Louisiana, and other sites.

This does not include the waste organic materials used for biodiesel, a subject to be discussed in the future.

Summary - Ethanol related CO2 sourcing
On the subject of ethanol, given all of the above stated concerning growth, feedstock type, emissions issues, grain shortages for food compared with feedstock for fuels, and second generation ethanol; the subject is ever-more vitally important to the CO2 industry, and will continue to be as such.

In terms of growing, current, and planned ethanol projects, and government mandates as a fuel additive or replacement; CO2 by-product should be recognised as a source of revenue.

Despite the method of designing this form of CO2 revenues from ethanol projects, it should become more important as we strive to source (due to high transportation costs) closer to the markets; as well as recognising developments of emissions mandates.

It is essential to understand CO2 markets, production costs, competition and sourcing developments, plus strategic sourcing; in order to best define and receive the benefits for properly developing the CO2 from ethanol projects.

All by-product revenues are essential for long-term health of the ethanol industry; and can be the key to best sourcing from a strategic and economic point of view the CO2 industry’s need.

About the Author
Sam A. Rushing is president of Advanced Cryogenics, Ltd., a CO2 and cryogenic consulting firm which is celebrating the 20th anniversary of the company.

Mr Rushing is a chemist, and a consultant to all forms of CO2 projects, including all technical and business aspects of the industry.