When I pretreat my WVO (filtered to 100micron) with the last batch of KOH glyc, I heat to 130F, add 6 gallons to 35gal wvo, then circulate for a couple of hours before shutting down.

Due to scheduling conflicts it was 4 days before I could get to it to drain, so it has cooled down to 70F +/-. When I drained it today, the glyc came out thick and looked grainy, however, i cannot feel anything when I put some between my fingers.

Also, I'm getting about 8 gallons of glyc back out.

So, why is this so thick and grainy (even with KOH), why do I get out more glyc than I put in, and for those that do the pretreatment, how does yours look?

thanks,

What is the titration number for the oil before and after the pretreatment?

Did you check for water content before and after the pretreatment?

Titration? I didn't tritrate this time, but it usually titrates between 4&6, and No I don't know the water content. I use a hand rotory pump to pump from drum to processor through a 1" clear hose. The WVO was good and clear amber.

OK, relatively dry, low titration oil.

The consensus seems to be that the thickening is caused by soap. The granular appearance would most likely be the pigments and trash that was in the oil to start with.

The volume of oil in the processor tends (not always) to increase with this treatment.

I kind of want to know the answer to this one. When you pretreat with glycerin that has koh and meth still in it aren't you possibly reacting the new oil too during pretreat and the 2 gallons of glycerin is actually just reaction from the new oil?

Unless you add extra to the glycerin, the KOH in the glycerin is consumed converting FFA to soap before it has a chance to make any methyl esters.

hey bio girl i tend to differ with rickdatech as there is left over koh in the glycerine its not enough to start a reaction at that concentration but it will help to deacidify the oil while the meth is absorbing the moisture out of the oil. i thought you only used new oil?

Actually turbowolf, we do not disagree on this. You said it much more eloquently than I did.

Biogirlz,

I doubt you would gain much from pretreating virgin oil. Maybe a little, but it is time consuming.

I do it every batch, but if I had virgin oil, I wouldn't consider it. Your time is worth something.

More than anything I just like to learn as much as I can but my thought was if it starts the reaction in a pretreat then it would take less meth. Since it des not then I wont do it. I am going to try the reduced meth recipe on Ricks site.
Thanks Guys

Well as far as the methanol goes, the school is still in session. Nobody on this forum really knows how much methanol is transferred to the oil or if there is a partial conversion.

All we have as arguments against that happening is that without a catalyst present the methanol prefers the glycerol. The problem in that statement is that we all know there is a catalyst present.

Many of us who have done the pretreatment witness pretreated oil boiling at 150 degrees Fahrenheit. That indicates that something other than water or oil is boiling. So through the process of elimination, it is most likely methanol. But nobody knows how much.

From what I have read catalyst is used to speed up the conversion. Given time, heat & pressure, BD can be produces without catalyst.

If you are recovering methanol from your BD & byproduct, it would make no sense at all to do this extra work especially when you are using virgin oil. I should be so lucky.

I dont recover my meth. Maybe that will be my next project but as of now I dont..
Ill stick to what I'm doing because it seems to work.
As far as the oil. If you were in the DFW area I could hook you up but Chambodia is a little far!

I actually asked this as a stand alone thread but found this string after. My previous question (posted in a bad spot I think):

I've searched the threads and {generally} have found support for using un-demethed glycerin as an additive to WVO to a) get rid of methanol in glycerin and b) to draw water and FFAs down into glycerin layer from WVO.

I did this by accident in my collection tank (previous post) and ironically my titration level did drop.

So, my question is this...

I have a 275 gallon & 330 gallon IBC tote over at my storage area (2,000 sf warehouse in an industrial park). Now that winter is approaching I will not be able to process as much as usual (collection tanks will fill quicker).

What are the benefits/dangers/drawbacks of pouring undemethed glycerin (KOH) in the bottom of each collection tank, say 30-40 gallons in each tank, while the collected WVO sits over the winter. Warehouse is around 45F during the winter (so the pipes don't freeze). Fire hazard? (I use 20% methanol and am not distilling at present). If I don't heat this mixture up to 140F like other posters do, will my doing this actually accompilsh anything (using the benefit of time?)

Wondering specifically is there any benefit of using the un-demethed glycerin as a layer sitting on the bottom of the totes to "draw down" water and deacidify WVO? No pump or heat activity going on here. Just resting comfortably.

Thanks in advance.

check link out, i did not have good luck with pre-treating \
http://biodiesel.infopop.cc/ev...19605551/m/867100262

Ben,
If it were me I would do just as you suggested. Pour in the glycerin and let it sit to soak up any water. I have glycerin in the bottom of all my settling barrels for the same reason.
There are hazards but not much greater then having 300 gallons of oil laying around, now it will just have some methanol in it. In a fire the small amount of methanol wouldn't even be noticed once the tote gives way...
Jon

Hi,
I, too have about 4-5 gallons of raw glycerin in my collection drums at the kitchens.

I dont know if it 'draws water down', but I'm sure it helps.
I've watched the cooks pour very hot oil into my drums and it gives a good circulation for a minute.

Brian