It *seems* that the distinction needs to be made between liquid acrolein (dangerous toxic scary, etc.) and the formation of acrolein and its effects as an exhaust emission
...which is not nice stuff, but in comparison to liquid acrolein is not the same sort of risk - as a product of combustion, it is present in its "acrolein" form for only a short time before reacting with sunlight and other substances in the atmosphere to degrade into other less harmful forms. I don't mean to say it is not a concern, but acrolein is one of the problems of combustion of diesel fuel too, not just glycerol. We are all exposed to it all the time, from diesel exhaust, and I believe its formation is related to combustion temperature, correct? As stated, it's very much an irritant, it's presence is detected easily and we therefore tend to avoid it, a natural response (in fact, I believe that the nose is under-rated as our built-in sensor for detecting substances in the air that might be harmful to us...not always reliable, but not bad - it's a device that's been under development a long time, after all!) You can burn diesel, glycerine, vegetable oil, or biodiesel and get a range of emissions, and sometimes you reduce one and get an improvement, but at the expense of another, so it's very often a tradeoff. That being the case you have to look at the exposure risks on balance, of the various emissions, and decide which ones you are most concerned about. Then do what you can to minimize those; and carry on and perhaps assess the risk on the others, based on exposure/dose over time, etc. If it is still a problem area (and it may not be, on balance, when looked at all our other various other exposures to environmental contaminants, indoor air pollution, for example) then look more closely at aftertreatment of exhaust....whether in a diesel or a glycerol burner - as your last line of defense before it hits the atmosphere. On Tuesday, February 17, 2004, at 05:39 AM, bob allen wrote: > Tom I agree with your post, just the chemist in me must jump in briefly > > [EMAIL PROTECTED] wrote: > >> The quick answer is no. Glycerin is a very viscous liquid, and the >> solidification point varies with the soap in it, the residual >> alcohol, and the >> completeness of the reaction. It is sometimes solid at 65 degrees F. >> What's more, it >> is dirty until it is at least partially refined. If there is no >> methanol >> recovery, it will have a volatile component and a refractive >> component. Glycerin >> flash point is over 800 degrees, and a waste oil burner will burn the >> volatile >> part, but not the refractive part, >> > the glycerin and other organic components will burn, but the sodium or > potassium hydroxide will be converted to their solid oxide forms (ash) > which may be a problem > >> which will quickly gum up the works. >> >> If glycerin is burned without enough air it may form a poisonous >> acroline >> > > thats spelled acrolein, but your right about its formation, > but is it really a problem? I would be more concerned about carbon > monoxide, undetectable, than acrolein, which has a very acrid > irritating > odor, and hence detectable. > >> compound. If you look at the structure of a glycerin molecule you >> will see three >> carbon-oxygen double bonds, >> > actually only single bonds, but yes it is "partially burned" > >> which are hard to break and take a lot of energy >> input. Carbon-oxygen double bonds are effectively carbon monoxide, >> meaning that >> the molecule is effectively partially burned already, and has a >> relatively >> low heat value per pound. >> >> A good glycerin burner handles a semi solid well, or preheats until >> it is a >> liquid. It has a fire starter of some other fuel, hopefully biodiesel >> or WVO, >> to get it up to temperature so the glycerin will burn. Then it has >> enough >> insulation to maintain this temperature, or at least has minimal heat >> withdrawal so >> the fire is not extinguished. It also has adequate air for clean >> combustion. >> I had to build this system because no standard burner does these >> things >> well. It is a masonry heater with a babington burner for a fire >> starter, burning >> WVO, and a secondary fuel feed for the glycerin. There are no visible >> emissions, and I hope that indicates a clean burn. >> >> Tom Leue >> >> >> In a message dated 2/16/04 1:30:45 PM, [EMAIL PROTECTED] writes: >> >> >> >> >>> In a message dated 02/16/2004 11:47:33 AM Eastern Standard Time, >>> [EMAIL PROTECTED] writes: >>> Burning glycerine >>> If I understand this correctly, I can take the by product from the >>> biodiesel. >>> That nasty looking stuff from the bottom of the processor and burn >>> it in my >>> waste oil burner with no problem. I have a factory bought waste oil >>> heater >>> that I burn all the crankcase oil from the trucks that I work on. >>> Is this a >>> correct statement? >>> >>> Rick M >>> Brownstown, Mi. >>> >>> >>> >> >> >> >> >> >> >> ----------------------------- >> Homestead Inc. >> www.yellowbiodiesel.com >> >> >> >> [Non-text portions of this message have been removed] >> >> >> >> >> >> Biofuel at Journey to Forever: >> http://journeytoforever.org/biofuel.html >> >> Biofuels list archives: >> http://infoarchive.net/sgroup/biofuel/ >> >> Please do NOT send Unsubscribe messages to the list address. >> To unsubscribe, send an email to: >> [EMAIL PROTECTED] >> Yahoo! Groups Links >> >> >> >> >> >> >> >> > > > -- > ------------------------------------------------------------------ > Bob Allen,http://ozarker.org/bob > ------------------------------------------------------------------ > ----------------------------------------------------------------- > The modern conservative is engaged in one of Man's oldest exercises > in moral philosophy; that is, the search for a superior moral > justification for selfishness JKG > -------------------------------------------------------------------- > > > > [Non-text portions of this message have been removed] > > > > Biofuel at Journey to Forever: > http://journeytoforever.org/biofuel.html > > Biofuels list archives: > http://infoarchive.net/sgroup/biofuel/ > > Please do NOT send Unsubscribe messages to the list address. > To unsubscribe, send an email to: > [EMAIL PROTECTED] > Yahoo! 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