Reprinted with permission from
www.graham-laming.com
Written by: Graham Laming

This is a compact home made biodiesel processor which avoids water-washing and limits methanol release to very small amounts. You can also recover surplus methanol from your biodiesel, which would otherwise be lost in the wash water.

You can de-water your oil in the processor and you can start to recover methanol from as low as 40 degrees C.

Here's a diagram of the system. It includes a simple venturi to recirculate vapour through a condenser. The venturi also sucks methoxide (or water, if you do the 5% prewash) from the methoxide container and mixes it into the oil flow.

Allow a straight horizontal run of around 30cm after the venturi outlet to ensure the venturi will perform properly. This is because the momentum of the out-flowing liquid acts to "pull" on the inlet vapour.

You can mount the methoxide tank higher up, nearer the venturi, if your venturi's performance is marginal. Make sure it is not too high - you don't want to drop the container, spill the methoxide, or hurt your back.

Parts :- You don't need to worry if you can't get exactly the same parts as I've used. The design is quite flexible and there are users all over the world who have successfully adapted the design to suit the parts they could find locally. I've added some links [here] to help put you in touch with other constructors.

My preferred layout ...

Here's another way you can inject methoxide or water - it will be familiar if you've used the appleseed design. Some pumps cavitate and lose suction with this scheme. If in doubt, use the 1st design, with valve V4 going to the venturi inlet.

An alternative way to inject methoxide...