I just cooked 50 gal. of glycerol for 2 1/2 days @ 180-190* and only recovered about 15gal of methanol. The 25 gal. or so I cooked on my first batch I recovered 13gal. around 50%. Why the drop in yield, I set everything up the same.
Any ideas???

 

Sounds just right. 15 gallons/ 50 gallons is 30 percent, the best I've ever done was 36 percent. I think the 13 gal/ 25 gal was a fluke, did you test that batch for the amount of Methanol? You might have carred over some water with it.........

 

I thought people were getting 50% recovery. The first batch might have been a little more than 25 gal it was the first time with my tank and I didn't mesure the amount going in. The glycerol was in a bunch of cubes, some filled more than others.
Another question?? When the glycerol is cooking my sight tube has mostly a clear liquid in it with the brown glycerol at the bottom, but when I drain it it all comes out brown-no seperation. What's the clear liquid??

 

Most likely a small amount of methanol, which recombines with the glycerol when you drain the tank.

 

So are you cooking the glycerol in your processor? The reference to the sight tube sounds like an appleseed....

 

Yes I'm using my apple seed type cooker with a condenser unit attached to the hotwater out side of the tank.

 

Interesting. I presume you are applying vacuum to the tank as well? If so, how much will it stand? I've read that H2O tanks can't handle much vacuum without collapsing...