Electrostatic separation of glycerol from biodiesel
Glycerol separation @ 1000V AC, 0.004mA

9 September 2006 - Graham Laming
Reprinted with permission from www.graham-laming.com

Warning:  High Voltage devices can generate lethal electrical shocks and can generate sparks capable of igniting methanol vapors. DO NOT use High Voltage devices if you are not experienced in their safe construction and use. Use high voltage devices at your own risk.

Doesn't seem to work for dewatering or cleaning WVO, unfortunately.

The glycerol is quite a light colour with biodiesel made from new sunflower oil.

Notice how the bottle shows no sign of separation at all, yet.

This technique works well on biodiesel made from high FFA oil too, and works with hot or cold biodiesel.

Here's another video using biodiesel made from waste cooking oil...

Guidelines on making high voltage source

Firstly, don't try any of this unless you are a trained electrical technician, familiar with the necessary safety precautions and procedures needed for working with high voltage. You need to protect yourself and those around you. I can't teach you what is necessary, so if you don't have a good understanding of this subject, don't try any of this.

A suitable supply can be made according to the general scheme below...

Instead of having both lines current limited, you could have one earthed, and the other current limited with twice the number of resistors shown for one line.

How can we apply this to a biodiesel process?

There are a number of possible ways to do this. Again, I am offering ideas only, it is up to you to develop a scheme to suit your process.

Allow around 25mm per 1000V plate spacing
Do not allow the electrodes to enter the glycerol layer.

Do not allow the electrodes to be exposed to an air/methanol vapour mix. You can achieve this if you ensure the electrodes are always submerged. This is to prevent the possibility of an arc occuring in the explosive atmosphere.

For those more experienced in building high voltage equipment, these links may be of interest...

http://www.techlib.com/electronics/highvolts.html
http://home.earthlink.net/~jimlux/hv/cw1.htm
http://www.kronjaeger.com/hv/hv/src/mul/
http://www.blazelabs.com/e-exp19.asp
http://www.rmcybernetics.com/science/high_voltage/voltage_mult.htm

For more information on electrostatic separation of glycerin from biodiesel  see here

Related Links

Using High Voltage Current for Continuous Separation of glycerin and biodiesel - pdf From Piedmont Bioofuels Coop