No doubt most of you have seen this by now, but in event you haven't, here it is: Glenn Ellis
Environmental Science & Engineering - <A HREF="http://www.esemag.com/index.html";>www.esemag.com</A> - May 2001 Production of a cost-competitive biodiesel fuel alternative to petroleum diesel Functional pilot unit located in Oakville, Ontario, processing one million litres per annum. Research has shown a number of important benefits of biodiesel fuel as an alternative to fossil fuels. The environmental and health benefits of this non-toxic and biodegradable fuel include its potential for reducing harmful exhaust emissions, decreasing green house gas (GHG) production and enhancing diesel engine performance as a lubricity additive. As well as contributing to a cleaner environment, the use of biodiesel, produced from recycled vegetable oils, agricultural seed oils or waste animal fats and grease, should also benefit and increase the income of the agricultural community in North America. Up to this point, however, the production and commercialization of biodiesel as an alternative fuel to petroleum diesel has seemed unlikely, due to the costs associated with its production (approximately three times as much as petroleum diesel). All companies currently producing biodiesel still employ a "high pressure, high temperature" method that is energy intensive and extremely costly. Or they use a chemical method that does not achieve ASTM standard Biodiesel in a one pass cost-effective manner. Both the seed oil (soybean, canola, etc.) and the yellow grease markets are at a historic all time low with regard to market pricing. It is anticipated that prices may remain depressed for sometime primarily due to the awareness of BSE (Mad Cow's disease) and the international effect it has on the animal proteins market. Biodiesel, however, could be produced from both seed oil and yellow grease. The Process The BIOX process, a new biodiesel process developed by the University of Toronto, has successfully demonstrated, in a laboratory setting, that biodiesel fuel (produced from recycled vegetable oils, agricultural seed oils or waste animal fats and greases) may soon become a viable, cost-competitive alternative to petroleum diesel. Professor David Boocock of the University of Toronto, and developer of the BIOX Process, has examined the process of base-catalyzed transesterification (specifically transmethylation) of vegetable oils to produce biodiesel methyl esters. The kinetic data for this reaction has been previously misinterpreted. At the University of Toronto he has shown that the methanolysis is slow because the initial reaction mixture consists of two phases, and the reaction is, therefore, mass transfer limited. The problem has been solved by the selection of inert co-solvents that generate an oil-rich one-phase system. This reaction is 95% complete in ten minutes at ambient temperatures, whereas previous processes required hours. Continuous processes are now feasible. The acid catalyzed process, which is required when the substrate contains fatty acids, is complete in minutes rather than the usual several hours. The traditional base-catalyzed method for producing fatty acid methyl esters from triglycerides and methanol has several disadvantages, including: The reaction is slow at ambient temperatures. The reaction does not go to completion, and therefore requires a second and even third pass to achieve the necessary purity. The reaction cannot handle substrates which have fatty acid contents much above one percent, simply because the acids neutralize the catalyst to form soaps.The new process addresses these problems in the following ways: Uses an inert, cheap, recyclable co-solvent to make the reaction one phase, thus improving mass transfer and thereby, the reaction rate. Uses more methanol to increase the polarity of the mixture, which maintains the ionization of the catalyst. For substrates containing fatty acids, it first uses a one-phase acid-catalyzed step to convert the fatty acids, before using base catalysis to convert the triglycerides. In the two-step process, approximately 30 minutes is required to convert the fatty acids at close to the boiling temperature of the methanol (60C). The base-catalyzed step is complete in seconds. Has a recycle stream of methanol and a co-solvent, and the latent heat of condensation is used to heat the incoming feedstock.The process is claimed to be the only biodiesel production process that will be able to compete with petroleum diesel on a production cost basis, and the only process that can successfully exploit high fatty acids to produce biodiesel. The process is able to deal with animal fats and greases. It is estimated that by using both used agricultural oils and waste grease, costs can be cut by as much as 50 percent, making biodiesel competitive with petroleum diesel. The costs of biodiesel using traditional processes vary depending on type of feedstock to be converted. If virgin soy oil were used as a feedstock, for example, production cost would be approximately $0.66/litre. The goal of the BIOX process is to produce biodiesel from any feedstock, including vegetable oils, agricultural seed oils, recycled cooking oils and grease or waste animal fats and grease, at a cost of $0.18/litre. See our home page on how to order your subscription. We regret we can only accept orders from Canada and the United States. [Non-text portions of this message have been removed] ------------------------ Yahoo! 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