> Does anyone know a process that can be > used to purify the glycerin produced in the > biodiesel reaction into a pure or high grade > glycerol ? High grade glycerol has a much > better market value than the crude ( 80-88% ) > glycerin you get with standard biodiesel recipes.
> David Cruse ....................... David, Here's the skinny on glycerin. To purify you will need to evaporate and distill it. The boiling point is above 500 Fahrenheit (read "boatloads of heat energy"). To reduce the heat input, you can evaporate and distill under partial vacuum. You're talking pressure rated, insulated tanks, a serious boiler, a major energy cost and uneconomical until you have a volume of "x" cubic feet of crude to distill. And that's when you're doing it safely but on the cheap. Even then you must meet food or cosmetic grade compliance for both the facility and the product in order to attain the higher value of pure glycerin. This means initial cost to meet the standard, continual and rigorous testing to insure product integrity, insurance costs for distributing food or cosmetic grade products and costs almost ad infinitum. Until you start producing several thousand gallons of biodiesel each week, the idea of refining glycerin is best left on paper or perhaps a pretty intense experiment. This truth really sucks, but no one can change the physical properties of glycerin. You could also experiment with glycerin as a furnace fuel or furnace fuel additive. Incomplete combustion generates Acrolein, however. It is extremely toxic and dangerous. One should be up on their combustion mechanics and chemistry before trying this. Or, you could toy with the conversion of glycerin to ethanol. This would be in the presence of the neutralized catalyst if you cannot determine a way to remove it before fermentation. This may or may not affect the yeastie beasties, depending upon their nature. In any event, you should be recovering the alcohol from the glycerin layer for economic and environmental purposes. That may not seem like much, but it is a start and gets you more familiar with evaporation/condensing techniques if you're not already familiar. It also reduces your VOC output if the alcohol of choice was anything but ethanol. The working theory is that biodiesel manufacture is intended to be green. This is one theory that can be practical in reality if all avenues are addressed Todd Appal Energy [EMAIL PROTECTED] Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html To unsubscribe, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
