Waste Vegetable Oil Fuels

Batch 3 is finally coming to a close. I’m giving it one last bubble wash as I type. Tomorrow I transfer it to the holding/drying barrel and then it’s to the gas biodiesel tank!

Last batch was a bit suspect. After testing it for unreacted mono and bi-glycerides, the result was no good. A layer of red brown glycerin dropped out. Bummer! That meant we did something wrong. Not enough methanol, too much water in the oil, not enough catalyst due to a bad titration… who knows. This time, however, with the help of master chemist Kevin. We were spot on. No glycerin out of this quality test.

There is one odd thing to my QC test result. That is the layer of gel-y stuff at the top. I can decide if it looks like a floating gel, or if it looks like an immiscible light layer. The second would make sense to me, and I’m hoping that it is just leftover methanol, since there was nothing to react with, it just hung around.

To do the test I took 5 g of KOH and blended it with 250 ml of methanol. To that I added 1 L of my biodiesel. I took half of the biodiesel right off of the top of the wash tank (I did let it settle after bubbling) and half off of the stand pipe that was in the lower 1/3 due to a small volume of wash water. I blended it up good and let it sit. After settling for some time, it cleared up and I could see no glycerin layer at the bottom. I wasn’t sure because the screw on bottom of my blender was obscuring my view so I transfered it to this growler bottle. That mixed it up again, but after settling here is what I ended up with.

So… the question is: “What is the top layer?” If it is methanol, sweet! If it is something else what is it and what will it do to my car?