Applications in the metallurgical industries
Since the background of this month’s magazine is non-ferrous metals, I want to start this piece with a review of CO2 usage in the metals industries at large. Globally, CO2 is over 20 million tpy in usage. If we look at the US specifically, of the approximate 8 million short tpy in usage, no more than 30% of this value would be found in all industrial applications for the product, including metallurgical in full. Industrial is intended to represent CO2 usage as an acid, agricultural usage, dry ice applications, usage in the chemical industries, to include usage in the metals industries. CO2 usage surrounding applications in metallurgical settings would include welding applications, that being CO2 in a gas mixture, CO2 usage has been found in large steel mills, as CO2 stirring application of metals in a molten state. This has also been the same application via the use of other gases. Some of the selection is a function of metallurgical composition and technical approaches; and of course CO2 pricing compared to LIN (liquid nitrogen) for example, as an alternate agent. One application for CO2 many years ago, now down considerably in foundry applications, was the use for hardening silicate based molds.
Therefore today, the lion’s share of CO2 (when dedicated to metals at large) this would be found in welding gas mixes in a wide range of metal fabrication industries, again, use in large steel mills as a ‘stirring agent’; and the application of dry ice in shrink fitting, during certain assembly processes. Next, a growing and ever ‘environmentally-friendly’ application and some of which was reviewed in the March edition of gasworld, is the application of very fine dry ice pellets (usually referred to as dry ice ‘rice’) for blast cleaning. Under high pressure, and via utilisation of the 1/8” dry ice product, metal surfaces are cleaned and/or prepared for finishing. The metal fab industries will always have some use of CO2, but of all the metal related industries, CO2 in blast cleaning is probably the most rapidly growing sector of the business. Availability and price drive certain applications in all that is mentioned above, with respect to the metals industries and carbon dioxide use.
CO2 from ethanol sourcing – Growing as a merchant and captive sourcing alternative
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. The reduction of MTBE due to its environmental problems and the surging prices for petroleum-based fuels are dramatically increasing the demand for ethanol. 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 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. Four feedstocks, including sugarcane which should be the feedstock for the growing ethanol mandated usage and production on mainly four islands in the Philippines.
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.
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