I started making biodiesel 2 months ago using an Evolution BioDiesel processor. So far the final biodiesel product has been great, but I have had one major problem with every batch I make: after agitation and the 14 hour wait, I find that when the glycerin settles at the bottom, it is completely solid, so I can't drain it out. It has nothing to do with temperature, Im in South Texas where the temperature is still getting into the 90's. What I've had to do is pump out the unwashed biodiesel into a container, and scoop out the solidified glycerin by hand, wash the tank, then replace the biodiesel. I thought at first I was putting too much lye or methanol, but in the next batches after my first one, I checked my calculations over and over again. This is still happening, its frustrating and extremely time consuming!!! Any suggestions?!

Use Potassium Hydroxide rather the the Sodium Hydroxide you're currently using. KOH will produce a liquid byproduct that will flow more freely.

Note, the base amount you'll need will increase the base catalyst quantity with KOH, as the two catalysts have different molar masses and purity varies as well. KOH is typically 90% pure - NaOH 99% pure.

ugh, if you're stuck cleaning out the tank by hand, you're probably inhaling all kinds of methanol vapors. Really bad design. if the tank was heatable and this happened you could at least melt some of the goo and get hot water to do the rest of the job.

What's happening is that glycerine (or rather, the soap that's in the glycerine) made from NaOH can solidify if the particular oil you're using is prone to solidifying. Or it can happen if your titration is over a certain number (we usually start running into this problem with 5 NaOH titration or higher).

 KOH will not do this, so it's a lot easier to use, and it dissolves into methanol more easily as well.

 If you've got NaOH to work with, you can use the 5% prewash method to decrease soap in your biodiesel as well as help prevent the problem:

http://www.biodieselcommunity.org/waterprewash/

Mark 

Will the liquid form of KOH work? And how do I calculate how much I will need?

Use the dry flake KOH. It's usually 90% pure.

Make your titration solution with 1g. KOH/1 Liter of distilled water. Titrate as usual. Use a base of 7g/L. To compensate for 90% pure use 7.8g/L - I use 8g/l. KOH is very forgiving if you over shoot.

I think KOH makes the process easier all the way.

Make some liquid soap with the Glycerin, and use it for everything from shampoo to floor cleaner!

Get legal Eagle's Soap Making Guide on my site.

Bob