I have been pretreating wvo using my stored up 5% prewash glycerin and it seams to work just fine. Has anyone else done this? My last batch of 54 gallons wvo 4 titration heated to 130 and added 15 gallons 5%prewash glycerine mixed for 1 hour and settled 24. The next day i had 60 gallons of 2.5 titration WVO that was VERY clean. It has worked so far.

I've been so anxious to do a bunch of 1L test batches to test aspects of this...but have gotten busy on my last couple weekends and haven't gotten to it.

This makes good sense to me given glycerine's polar ability to grab water: so long as you don't saturate the glycerin it will pull water from WVO even with the 5% prewash water in it.

The downside I can see, though, is that the idea of using glycerin as a transfer fluid for methanol likely won't work with 5% prewash glycerin. As water and methanol are so miscible, I just don't see the methanol moving to the WVO from the glycerin if there is water present in the glycerin.

But glycerin, even 5% prewash glycerin, as a water-stripping, FFA-reducing agent for WVO, that is starting to have good supporting evidence.

I just reread your post closer...you gained 6 gallons of WVO after treatment? Trapped BD, you think? Have you made fuel from this WVO yet? Did it react normally and then come out as a clean 3/27 pass?

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you gained 6 gallons of WVO after treatment?

If so, did the glycerine go down to 9 gallons? What consistency?

I am sorry, I went from 56 to 60, not 54 to 60. I only gained 4 gallons. Had my numbers backwards in my head. I put three jugs of glycerine in (5%prewash) and the next morning only drained 2 off. Glycerine was very very dark and thick like pancake syrup. When I took the lid off my proccessor to look at the pretreated WVO the methanol smell was like I just added methoxide and the top appeared to be a bit of biodiesel. The recovered glycerine now thicker and blacker did not have any methanol smell anymore, so the WVO took it. I know from distilling it that I recover 20-21% and lowered meth accordingly. Reaction was perfect. fuel is beautiful.
Now I can't decide on water washing or recovering methanol and settling. I am concerned that the fuel will not be as clean with no water.

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Glycerine was very very dark and thick like pancake syrup. When I took the lid off my proccessor to look at the pretreated WVO the methanol smell was like I just added methoxide and the top appeared to be a bit of biodiesel.

Wow...this would almost imply that the WVO is somehow preferentially picking up the methanol and not the water...or the inverse, that the glycerin is preferentially giving up the methanol, but not the water.

Goodness...now that I GOTTA try this weekend!

Heres a Thread about this.
http://biodiesel.infopop.cc/eve/forums/a/tpc/f/4441089311/m/6771041932/p/1

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Heres a Thread about this.

I know that...but in that instance he is advocating using glycerin with no water, as it was felt the water would transfer to the WVO too. Here, the methanol seems to be transferring without the water transferring.

I've been meaning to run a series of experiments off of that thread anyway...but now I have one more to add.

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Originally posted by Ryan P.:

quote:

Heres a Thread about this.

I know that...but in that instance he is advocating using glycerin with no water, as it was felt the water would transfer to the WVO too.

I'm actually more worried about the water interfering with the reaction between the methanol/lye and the oil you are pretreating. I'm concerned that water + lye + oil = soap.

Maybe I don't need to worry about it and just accept the fact that it will happen. I will loose some yield, but in return I will get to use some of my methanol to pretreat. I wonder if there is some preferential sapifocation of the hamburger fat instead of the canola oil. Maybe that is why doing this seems to help with cloud point so much.

-Jim

I am on my 3rd batch of pretreating with watered gly as we speak. I will let you know tomorrow how this one goes. What is really neat, is the fact that the glycerin from the reacted bio is very clean because the pretreating removes the remaining crud from the WVO. then you chuck the pretreating post drained glyc so you don't get them mixed up. I would think that cleaner WVO would make cleaner Bio. sorry - thinking out loud again. I also don't mean to take away from the original post about this, I am just going a diff route by using prewash to get more meth in the glyc.

Here's my experimental plan for the weekend. If you see something important I am missing or info that could also be generated from my procedure, let me know and I'll try to add it.

-add know vol water and methanol to demethed and dried glycerin.
-50ml water, 50ml methanol in 150ml glycerin

-add this controlled 5% prewash glycerin to 750ml WVO that is titrated and boiled dry first

-warm mix to 130F and mix for 1hr

-separate and measure 2 volume fractions

-boil methanol and then water out of post-treated WVO to determine weigh %’s of each that transferred


Then I've got my spiffy little excel graph I'll be filing in and we'll see what turns up.

Wish me luck!

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Originally posted by Ryan P.:
Wish me luck!

Luck.

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Then I've got my spiffy little excel graph I'll be filing in and we'll see what turns up.

Wish me luck!

I look forward to your graph.

I wonder about one part of what you have described:

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-boil methanol and then water out of post-treated WVO to determine weigh %’s of each that transferred

I know that water and ME have different BP's, but won't some water start to come off as you begin to heat?

PS. I know someone who is running some experiments on how much methanol they can recover from byproduct that has been used for pre-treatment compared to byproduct that has not been used. I need to wait for them to announce the results when they feel the data is solid. I think people will find it interesting.

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I think people will find it interesting.

Can you give a hint, Andrew?

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but won't some water start to come off as you begin to heat?

Yeah, they are going to be fuzzy numbers. What I'm hoping I see is a sizable weigh loss by 180F, indicating the methanol and maybe a little water boiling out, and then no significant change by 250F, indicating that water didn't transfer from the glycerin to the WVO in any significant amount.

I'm REALLY looking forward to doing this!

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how much methanol they can recover from byproduct that has been used for pre-treatment compared to byproduct that has not been used

In a perfectly designed system there should be no difference (or very slight)...but that system would be a very well controlled reflux column and probably not worth the effort for 99% of available recovery vs. 90% of available, IMHO.

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Can you give a hint, Andrew?

I'll ask him...

So I didn't quite get finished over the weekend.

quote:

-add know vol water and methanol to demethed and dried glycerin.
-50ml water, 50ml methanol in 150ml glycerin

Done

quote:

-add this controlled 5% prewash glycerin to 750ml WVO that is titrated and boiled dry first

Done

quote:

-warm mix to 130F and mix for 1hr

Actually mixed for 2hrs

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-separate and measure 2 volume fractions

I was losing methanol and/or water during mixing as my jar lid was leaking. So I need to look at this more closely tonight to pull any useful info from it.

quote:

-boil methanol and then water out of post-treated WVO to determine weigh %’s of each that transferred

Still pending. I may need to repeat entire experiment to pull this info out, due to my leaking lid.

OK, lets see if I can format this thing into something that makes sense...

*************************************************************************************************
______________________Before___After___Total Sample Volume
5% Glycerin Volume (ml)__310_____400________Loss to Heating (ml)
WVO Volume (ml)_________750_____620_________40
WVO titration____________8______NP
5% Glycerin Weight (g)__120_____376
WVO Weight (g)__________703_____583
WVO Weight/ml__________2.11_____2.36

WVO Boil Fractions (g) New Weight___Weight Loss___Fluid Density (g/ml)___Fluid Volume in WVO (ml)
@180F (methanol gone)___575______________8__________0.7913__________________6.3ml Methanol
@250F (water gone)______547_____________28____________1_____________________28ml Water
*************************************************************************************************

OK, let's see if I can now interpret it.

1) I lost 40ml total volume while heating. Lets assume this was almost entirely methanol; ~6.3ml of methanol was found in the WVO, meaning theoretically, 63% of the methanol remaining was in the WVO (6.3 of (50ml-40ml lost)). This may confirm that WVO will attract methanol more strongly than glycerin.

2) 28ml of water remained in the WVO. 110ml of water was added to the glycerin, meaning 25% of the water in the glycerin transfered to the WVO. An additional 60ml of water than was added beyond what was planned may have saturated the glycerin's ability to hold water and contributed to this observation.

3) The glycerin picked up volume at the loss of the WVO: this was likely hydrogenated fats (note the disproportionate weight increase of glycerin) and also some loss to an emulsion region between the layers that I couldn't separate well.

4) I did not perform a second titration yet. But we already know raw glycerin reduces titration, so no new information to be gained there anyway.

Bottom line: I want to repeat this test next weekend. I think some very valuable info can be gathered from it if I can eliminate my weak points.


Can anybody else tease info from my data that I didn't see?

Trial #2
----------------------Before---After----Total Sample Volume
5% Glycerin Volume (ml) 256----240------Loss to Heating (ml)
WVO Volume (ml)---------750----700---------66
WVO titration-----------6.6----4.5
5% Glycerin Weight (g)--125----not taken
WVO Weight (g)----------658----628
WVO Weight/ml----------0.877---0.897

WVO Boil Fractions (g)--New Weight-----Weight Loss-----Fluid Density (g/ml)-----Fluid Volume in WVO (ml)
@180F (methanol gone)------620-----------8-------------0.7913-------------------6.3304
@250F (water gone)---------618-----------2-------------1------------------------2

Controlled 5% Glycerin = 46ml water, 50ml methanol, 160ml dry glycerin
*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*

I thought I had sealed well, but still had a volume loss of 66ml. There was no indication of materials escaping past my lid seal. I don't really know how to credit the 66ml volume loss...perhaps a volume of methanol does not increase a volume of oil by the volume added.

Just over 6ml of methanol was found in the WVO following the pretreatment. A mere 2ml of water was found in the WVO following pretreatment. This would be 15% transfer of methanol and 4% transfer of water. I think I have loosely confirmed the idea that methanol will more readily transfer out of glycerin than water will.

It was not a pretty test, and doesn't make exact sense, and I could probably re-execute it a dozen times before I got a clean test. My little shed just isn't a controlled enough environment right now, and my equipment not well enough controlled to run the test as precisely as I had wanted.