I ran a 26.5 gal batch: 20 gallons of incompletely reacted bio/oil with 6.5 gallon of fresh waste oil. Titrated at 0.2g (KOH). The fresh waste oil typically titrates at 1.0g. After rection, I let it sit for 35.5 hours for the glycerin to settle. After I drained the glycerin, which by the way did not look nearly as thick as usual, I pumped to reaction into the wash tank (120F), I got immediate emulsion. It has failed to budge one bit in four days. I've had separation happen in a matter of minutes, hours, or even days before. But this is mostly reprocessed bio, and it is baffling me.

The plan is to remove it from the tank. Let it sit for however long it takes. But any ideas on what could have caused this? Too much methanol? Too much KOH? Mixing semiprocessed oil with fresh waste oil? Something else?

veg
- Wow! the by product would be thinner because some has already been removed.
-what is your wash method? ,how much water , hot or cold? anyway all these questions won't fix the problem right now.
-for now calculate 7ml of vinigar for every ltr of water you used for the wash , and mix that in go easy! things should start to seperate right away, if not repeat the step. no need to worry about the vinigar in the bio, it will wash out.(some people use salt, but I'm not a fan of that because there is no way to check if it is all washed out.)
-on your next batch do a 5% pre wash prior to removing the byproduct, or if you remove the byproduct cut the pre wash to 2% water. do the following washes with not more than 5% water and you will never have this problem again! use warm soft water if you can, cold water will require more washes. the wash water will seperate in 1 hr and you will be ready to start the next wash.
-I think what happened here is some of the byproduct stayed suspended in the biodiesel, it is difficut to see the separation between byproduct and biodiesel in reprocessed batches. Tom