I make 35 gallon batches with 22% methanol. I was curious if there was some percentage of methanol that i should be able to recover?

I don't keep exact records. it seems that I make every batch a little bit different...
but I would suggest between 25 and 35% of the glycerine is methanol.

the last recovery run, I got about 12 gallons out of 55. but I also use around 10% water for prewash( sometimes?? )

I know not exactly what you looking for, but never cared to keep exact records.

-dkenny

Just curious..thats all. Im still building my meth recovery unit. I have stocked up about 100 gallons of methanol now, and i got to thinking about where i was gonna store the methanol when i start recovery...

dkenny,

If those #'s hold up, two stage with no methanol recovery can use less methanol, or the same, than single stage (assuming 22%) with recovery.

Which way do you think is more work, single stage plus recovery, or two stage?

I ask because I have exactly 0 experience with recovery.

Andrew

Somewhere in the GL One Day thread I think he said you can expect to get 2% back from the BD. That is about what my experience has been, but I am using vacuum distillation instead of the venturi and heat method that he uses.

I have no experience recovering methanol from glycerin, though I want to try it soon.

quote:

I would suggest between 25 and 35% of the glycerine is methanol.

Cool...and the number I had stuck in my head was 15-18%...wonder where I got that.

If 25-35% of my glycerin is methanol, the $150 I've spent to build my still-no-quite-done methanol recovery unit should be recouped in no time...I have 300 gallons of glycerin to run through it! That's 75-100 gallons of methanol!! I'm gonna need a bigger recovery catch barrel...

Hi Ryan,
keep in mind that we are overdosing the meth by more than 100%
Only abt. 8-10% methanol (from the whole batch)is used by the reaction. The rest is used to drive our reaction to the right side and to achieve higher conversion.
This means, that more than 50% of the methanol must be in the byproduct or the BD at the end of our reaction.

good luck

Dieter

I'm currently distilling around 13.5 gallons of pre-wash glycerin and I'm getting around 3 or 3.5 gallons of methanol. That works out to be about
22-25% or so of my original gly volume.

I use 22% methanol in my reaction and 5% prewash. When I run the purity numbers, by weight, it seems that I'm getting high 80's purity.

Dieter,

quote:

Only abt. 8-10% methanol (from the whole batch)is used by the reaction.

Where do you get those figures from?

Figures I get from chemists, and people who play them here, are in the range of 12-13% being used in the FAME.

Hi Andrew,
I got these figures from hielscher.com,
google for "hielscher Biodiesel" to find the link.
Very interresting page, for ultrasonic reaction.
Before u ask, I have nothing to do with them,
i`m only searching on the inet for a year now,
while planning my own process.
Hielscher claims a very short processing time
with their ultrasonic equipment.
They link to a paper, but I could not load it from the web :-)), because u have to pay for it.

On their site they have some diagrams.

Take a look there.

good luck Dieter

What heilscher also says is,
that u can achieve a higher conversion rate with
KOH, compared to NaOH with a shorter reaction time.
I will go for that.
Does anyone has any informations abt this ???


Dieter

Dieter,

I am about 99.95% sure they are wrong about 8-10%.

I'll take a look though.

Check out this: Producers' Post at the top of page 2. Sounds pretty convincing to me.

Hi Andrew,
yes, you are right, I read this page several weeks ago, but didnt bookmarked it :-( and
after all that reading abt BD my brain has a little flew called "alzheimer light" :-)

But also with a stochiometric calculation (13,3%) by weight, there is enough meth to recover and ever a bit more, because we cannot get 100% conversion.


br Dieter

Andrew,
you ask some good questions..we think a lot alike.
but in the end the difference is how much methanol is used in process and how is in the biodiesel.

so if 12% is in the BD, 12%+-1 or so, and we start with 22% then 10% is left in the gly.
no matter how many stages of base or acid/base/base are used.
but if we only use 18% or 14% the numbers change.

I haven't tried to run the ROI on the varying input amount of methanol. a gut feel would suggest that 14-16% starting...forget methanol recovery unless you have an ultra efficient( cost wise not time wise) method. using the Sun for most of heating and taking days is one idea.

of course there's the unknown amount of methanol that stays in the BD but not part the methyl ester.
all this is effect by the $$$ paided for the methanol. a friend of mine found some reclaimed methanol and other stuff in it for around $100/55 gallons..great deal the stuff makes great BD. but worth recovering the methanol??

-dkenny

Well I dont know much about all this scientific mumbo jumbo but if i put 2 cubies of glyc. in my still, I drain out 1 and 1/4 cubies of glyc. when its finished. I get about 2 gallons near 100% methanol and the rest (less than a gallon aint that pure.

Tiger,

That fits with the 25-35% idea. What percent methanol do you use in your original reaction?

I have found that using my 2 Still Design which uses air bubblers to bubble both the Glycerol and the Biodiesel while distilling, that when I have used 22% methanol I get 36% recovery and 26% recovery when using 20% methanol/wvo so the 25-35% is spot on.
However I think a vacuum could be best, because after I have moved out as much methanol as I can I move the bio to the washtank where it is bubbled for another 24hours and the total volume drops by approx a further 5 litres. This is possibly a combination of things. I suggest a large proportion to be methanol, maybe small amount water and heat expansion as it is at around 70DegC when put into the tank and cools down over the washing process.
But if that is mainly methanol there is a possible oppertunty to collect more methanol...?
What sort of numbers are people getting with vacuum recovery?
BTW. My last batch processing 150litres wvo with 20% methanol past 3/27 in a flash (didn't even have to shake the test) and recovered 8litres 100Proof Methanol using a Alcolmeter to test purity....

I've been homebrewing for about a year now and am just getting interested in distilling methanol.
I have read this thread and feel like somone else needs to reply to some of the previous questions and statements cause I feel like I'm just hang'in
here.
I want to build a still, and I think it's gonna be a two still design.
And for your information, considering the cost of methanol, what ever % I can recover - yes it is worth it.

attempted my first methanol recovery operation yesterday.

14 gal gly
heat to 155-160f
runs vapor through 3' plumbers delight.

I got 13 gallons of very dark liquid, flowing through the condensor and was left with roughly 1 gallon of very thick glopy glycerin. The methanol never ran clear...it was always dark. (if thats what i was recovering in the first place...)

So what did i do wrong?

Sounds like you didn't have enough head space in the heating vessel and the foaming glycerin got into the condenser. As the methanol starts to boil out it makes big glycerin bubbles, bigger as the glycerin gets thicker. You need to have enough room to allow these bubbles to pop before they can force glycerin into the condenser.

I have a 3' vertical region before my condenser so nothing but hot methanol makes it to the condenser...it also does a pretty good job of excluding water from the recaptured methanol.

Here it is: