# What To Do With Glycerine



## YuccaFlatsRanch (May 3, 2004)

The major by product of making Biodiesel is Contaminated Glycerine. What do you do with this stuff??


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## Steve L. (Feb 23, 2004)

Nitrate it? :shrug:


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## Tater'sPa (Jun 27, 2002)

I think it can be composted after letting any excess methanol evaporate or boil off
Maybe it could be added to detergents and used as a degreaser.....maybe even by itself.
Possibly for dust control on dirt roads or driveways..not sure about uncle EPA on that one...


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## Explorer (Dec 2, 2003)

Make contaminated soap?


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## WisJim (Jan 14, 2004)

I have seen some biodiesel makers market a line of soaps as a sideline, but I think that the glycerine is one reason to use straight veggie oil instead of biodiesel for many people.


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## jefferson (Nov 11, 2004)

suppositories????


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## greg273 (Aug 5, 2003)

You can recover most of the residual methanol from the glycerine, by distillation. In a 5 gallon batch of 'waste' glycerine, there is approx. 1 gallon of residual methanol that can be recovered. We've done the math, and using about 50cents worth of electricity, you can recover $3 worth of methanol. We've been using discarded electric water heaters, fitted with a condenser, to do the process. You simply heat the glycerine to 175degrees F, and the methanol will begin to boil out. (okay, methanol has a 145 degree evaporation point, but you must get the temp up to 175 to push it out of the glycerine mixture) You will be dealing with explosive and dangerous chemicals and temperatures here, so do your homework and be very careful. But it is doable, and the process is simple and low-tech. We have been using this process safely and effectively for about 2 years now, with no incidents. There are better, less energy-intensive ways to accomplish this, using an applied vacuum to the distillation, but I havent looked into that very much.

The remaining de-methanolized glycerine can be composted or burned. I've heard of people using glycerine in place of heating oil in oil burning furnaces.

The glycerine from potassium hydroxide (KOH) stays liquid over a broader range of temps, whereas the glycerine from sodium hydroxide (NaOH) becomes solid much easier. I've found the KOH glycerine is much easier to deal with for that reason.

Good luck, and please be very careful. Methanol is nothing to fool around with. I would like to start experimenting with ethanol for making biodiesel, it is much less toxic.


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## MELOC (Sep 26, 2005)

just wish to add a word about safety. methanol can poison you simply through absorption through the skin and probably by prolonged exposure to the vapors. always wear gloves when handling the stuff and be sure to ventilate the work area. my cousin was simply using the stuff to work on shipping/coding printer jets and became ill from absorption.

i thought glycerine was a product that could be sold... to cosmetic companies for example.


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## greg273 (Aug 5, 2003)

Yes, definitely stay out of the methanol fumes. There are no readily-available respirators on the market that protect against methanol fumes for more than a few minutes. And yes, absorbing it through your skin is just as bad.
If handled carefully, you can deal with methanol and all its inherent dangers, just be extremely careful. There are ways to make biodiesel and distill methanol from waste glycerine that minimize, if not eliminate, exposure to methanol. The fumeless closed systems in common use today are one example of safe ways to make biodiesel. Of course, lots of people, myself included, went through the learning curve and made lots of mistakes along the way. Most of us are still around and healthy, having upgraded our processes and learned from one another. ( I started out making biodiesel in a 5 gallon bucket with a paint mixer, and trying not to inhale fumes. Not smart, and thankfully that stage didnt last very long). 
Learn from someone with some experience, or do your homework and proceed VERY SLOWLY. Start small, making 1 litre (or smaller!) batches, and learn the process. Once you have the basic process down, you can make larger and larger batches, improving your efficiency, and making it worth your time and energy.

I would like to add that yes, some manufacturers will buy glycerine, but they want 100% pure glycerine, the stuff left over from waste veggie oil is about as unclean and impure as it gets. It would take massive amounts of energy (and specialized distillation equipment) to make a product any company would be interested in buying. And then they'd probably only want to buy it by the railroad tanker load.


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## michiganfarmer (Oct 15, 2005)

greg273 said:


> The remaining de-methanolized glycerine can be composted or burned. I've heard of people using glycerine in place of heating oil in oil burning furnaces.
> 
> .


I fit burns, why not leave it in the bio diesel?


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## greg273 (Aug 5, 2003)

michiganfarmer said:


> I fit burns, why not leave it in the bio diesel?


 Once you make 'biodiesel', you have split the oil molecules into ESTERS and GLYCEROL, and the ESTERS are the molecule that has the proper burning and viscosity characteristics to be used in an unmodified diesel engine. The glycerol is too heavy and too viscous to be used that way. 'Leaving the glycerine in' would be essentially using straight vegetable oil, which can be done, but the oil must be heated to bring its viscosity to the proper level.


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## MELOC (Sep 26, 2005)

not arguing, just curious as to why so many folks have luck burning straight veggie oil without processing it? i know some folks mix it with diesel too.


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## greg273 (Aug 5, 2003)

MELOC said:


> not arguing, just curious as to why so many folks have luck burning straight veggie oil without processing it? i know some folks mix it with diesel too.


 Yes, straight veggie oil (SVO) will burn in a diesel engine, it mostly depends on the temperature of the oil. You can mix it with petrol diesel also, which in effect 'cuts' the oil to the proper viscosity.
Those who burn SVO on a regular basis in their diesels are most likely using the 'two tank' system, like those popularized by the folks at 'Greasel' and a few other companies. In this setup, the engine is started on either petrol or biodiesel, or a combination, then coolant is routed into the second tank of SVO, thereby warming it up enough to be used. When the SVO gets to the proper temperature (160F?, i believe...), a switch is flipped that draws fuel from the SVO tank. About 5 minutes prior to shutting down the engine, you switch back to the first tank, petrol or biodiesel, and let the injector pump and fuel lines be purged of SVO. Its an nifty little system, one I hope to use someday...
So with SVO, you modify the vehicle ONCE. With biodiesel, you leave the vehicle alone and modify the FUEL. In the long run, its probably easier to modify the vehicle ONCE and be done with it, but, I have heard varying reports of SVO leaving behind deposits on the injectors, so before I switch I will do some more investigating on that.


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## Jim-mi (May 15, 2002)

I was told by the instructor, at a very recent class on biodiesel, that the burning glycerine componet of the veggie oil leaves a "glaze".
I haven't (yet) read that as a problem--running SVO.

Or do the guys just have to do the diesel "purge" more often ?
Any way, my newly aqqired 300D (and me) need some answers . . .lol


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## michiganfarmer (Oct 15, 2005)

good information. Thanks Greg


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## rambler (Jan 20, 2004)

greg273 said:


> The remaining de-methanolized glycerine can be composted or burned. I've heard of people using glycerine in place of heating oil in oil burning furnaces.



Is it simple to burn the glycerine in a fuel oil furnace, or do you need to remove the methanol first, & then a lot of other stuff?

My understanding is the glycerine is more the fatty solids of the oil?

Interesting thread.

--->Paul


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## greg273 (Aug 5, 2003)

rambler said:


> Is it simple to burn the glycerine in a fuel oil furnace, or do you need to remove the methanol first, & then a lot of other stuff?
> 
> My understanding is the glycerine is more the fatty solids of the oil?
> 
> ...



Paul, I believe you can burn the glycerine with the methanol in it, I've heard nothing to the contrary. As I stated earlier, the KOH glycerine stays liquid over a much broader range of temperatures, I wouldnt want to put NaOH glycerine in a storage tank, because it would solidify in a few days! Not very good in a gravity-fed tank situation. Hopefully someone with some direct experience will weigh in on this...

A good way to visualize the chemistry of biodiesel is to imagine the oil molecule as a sort of '3 legged octopus', with the heavy, glycerol molecule as the head, and 3 long chains of hydrocarbons as the legs. The catalyst provides a 'workbench' for the alcohol to cut the head off the octopus, at which point the alcohol attaches itself to the 3 hydrocarbon chains, leaving the heavy glycerine with nowhere to go but out of solution. What you are left with are long chains of easily flowing, low viscosity hydrocarbons, now called 'methyl esters', each containing its own built-in alcohol molecule. Very good for internal combustion engines...


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## Ross (May 9, 2002)

I know oil furnaces but not gycerine (Ok we had some residule left from soap making and it didn't look promising for use anywhere.) I doubt you get gycerine to pump through the nozzle. You'd certainly want a two line system with no bypass plug in the pump! There's a sintered bronze filter on most nozzles that would plug very quickly, and I'd think you would go through a lot of prefilter elements too. Some have screens instead they might be better. Maybe with a little heater on the drawer assembly too? Now maybe a used oil furnace with the added compressed air.......... It's not going to be a simple process.


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