I am trying to find something to make a heater to recover the methanol from my glycerin out of, and came across an old air compressor pressure tank. It is in good shape, and looks like it will hold 10-15 gallons. I was wondering if anyone has made a unit out of one.

What I planned was to stand it on it's end and weld on some fittings for a water heater element, and plumbing, then insulate it.

I am just getting started making bio, and have not de-methed glycerin yet, so am not sure if this will work, or if I need to look for something with a removable top (the plans I have seen usually call for a metal 5 gallon pail or something similar). I really want something that will do 7-8 gallons at a time, so I don't have to do the recovery twice with each batch.

Will the warm glycerin flow out of a standard 3/4" valve after being de-methed, or will it get too thick, and need to be removed from an open top?

Any ideas or pictures of de-mething heaters would be appreciated.

This message has been edited. Last edited by: JunkMan,

Heres pictures of ours http://www.biodieselpictures.com/viewtopic.php?t=614

We use a 550watt element with 110v. I think the reflux column is key, we get 99% methanol. You have to empty the glcyerin while its hot or it will go solid

Here's one made by tgomes (hope I'm not stealin' yer thunder)

http://www.biodieselpictures.com/viewtopic.php?t=444

Just a comment on de-mething glycerin sorry if this is off topic.

After you have recovered your methanol would it be ok to just add some amount of water to keep it liquid or in addition to that would it be good to acidify also?

quote:

Originally posted by paulb3:
Just a comment on de-mething glycerin sorry if this is off topic.

After you have recovered your methanol would it be ok to just add some amount of water to keep it liquid or in addition to that would it be good to acidify also?

Sure! and if you're processing with KOH then add 50g KOH per liter of glycerin into your water and voila you've got a great liquid soap! Water should be 50/50 to the glycerin.

quote:

Originally posted by Paulus:
Here's one made by tgomes (hope I'm not stealin' yer thunder)

http://www.biodieselpictures.com/viewtopic.php?t=444

Thanks, that's similar to what I was thinking of.

Actually it is just a GL system that gets filled with glycerin about every 4 to 5 batches. Use a Thermocouple at the condensor head and it's all good. Keep the glycerin hot till it is drained though or else there is no way to get it out

Tony

Make sure you turn off the heater before you drain the gyc. "Bang" been there done that.

Hi Tony

When you're recovering methanol, is foaming ever a problem? I reprocessed a bad batch the other day. During methanol recovery stage too much heat or venturi flow produced so much foam it started running through the condenser and into my methanol recovery bottle.

when the methinol starts to biol off, the glyc/methanol gets foamy, and yes some of it can end up in your meth recovery tank. to solve , put less glyc. into the still . or simply let the meth/ glc mixture you have collected settle out and decant the methinol from the top

So far I have had no issues with foaming in my GL push/pull style water heater reactor.
I vacuum distill and have about a 36" piece of 1/2" black iron pipe with a heat trace on it on a 45 degree angle up to the top of my condenser. I also put a piece of 0000 steel wool in the union at the tank where the pipe attaches, I thought it may help to break up the foam. I also have a small valve at the vacuum pump to regulate the vacuum, when it looks like the methanol is overloading the condenser I can throttle it down with the regulator. So far so good.
I did not have very good success until I added the heat trace to the pipe now it works great!
You can see the pipe and heat trace in this picture after removing the insulation.

Jon

With 40 to 50 gallons in the 60 gallon tank there seems to be plenty of head space. Foaming has not been an issue.

Tony

Yeah this was a very soapy batch due to THREE reprocessings...water got it in at the start somehow...also had a lot of fat. Think it was due to the pump flow rate, but as methanol recovery progressed even small amounts of venturi air and/or heat caused the foam overflow.