I've been using this method for quite some time in my BioPro. I really think it helps bump your fuel quality up there. Stuart

Yeah; I want to do it again this next weekend, though, as I had a couple little mistakes I'd like to fix.

Here's what I reported in this thread.

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.