Hi I'm new here and don't know much about BioDiesel, But I have played around with electro static stuff.
Sources for high voltage devices for those who want to experiment are old laser printers and copiers they have a + output of about 1000V a negative of about 400V and an AC output.
For those who like to live dangerously TVs and monitors have a 20,000V output attached to the tube, it's the thick wire that plugs into the side of the tube WARNING an unplugged television can still electrocute you, You have to drain the tube to ground. Neon transformers vary in voltage and current.
If you stay below 20 milliamps it shouldn't kill you but it will still hurt.
Electronic hobby shops sell kits to make jacobs ladders which are high voltage low current and are safe.
Plastic holds an electro static charge and so does glass so maybe you could wrap some alfoil around the bottom of a glass container and and have a nail(sharp objects work better for charging gases)in the center.
It would all need to be insulated from ground, even damp air can cause voltage leakage.
Sparks jump about 1mm per thousand volts in air and a spark could be dangerous if there are any methanol fumes.
I once tried to clean engine oil with electro-statics with no success, it was to viscous, I think WVO would have the same problem. Hydraulic oil is cleaned this way but is much thinner like Bio.
If you want to check if something is charged like a plastic drum use a small piece of tissue paper close to the drum, a charge will cause the paper to move either attracted or repelled.
Do not use a volt meter it will probably die and wont read the voltage anyway.
I'm itching to try this so I better make some Bio.
Really glad I found this site I have learned so much.

Does anyone know how to calculate the voltage required for a given gap?

Graham,

is your method really electrostatic or does it require an actual current going through the mix? does it work better with AC or DC?

Hi ScottSEA

Try 25mm per 1000V as a rough guide.

Hi Harry747
There is a leakage current, but it is very low, and reduces as the work being done reduces (as the biodiesel becomes more pure)

Here is a page which may be of interest. The 1st video has probes 20mm apart, 1kV AC, passing 0.004 mA

AC and DC seem to work similarly well.

Hope that helps,

regards,

GL

Graham,

This is extremely intriguing work. I have experimented with ultrasound coalescence promotion (but not on bioD yet.)

I have an embarrassing question: do you think there is any possibility that simply applying an electrostatic field without immersing the plates might work? As in simply making one large capacitor across the outside of the glass jar with similar voltage gradient? Apologies if this was previously discussed.

Hi Nick

No, unfortunately is seems necessary to have the electrodes in the liquid iteself, so it is not a purely electrostatic effect.

I used a glass jar, with half the surface covered in aluminium foil on each side, and connected each 'plate' to 4000V AC 50Hz - 400Hz..

No effect at all I could measure.

So there is some conduction required thru the fluid, albeit at very low current.

The external plate idea may work if the frequency is raised, I haven't tried above 400Hz.

Hope that helps,

Graham

Hi Graham,

I was studying my old Organic chemistry text for new ideas and trying to find reaction rate rankings when I stumbled upon the Kolbe decarboxylation reaction:


Salt of carboxylic acid(soap) + electric current ---> hydrocarbons (from radical dimerization of the non-polar tails of the FFA salts)

I think this might be what you are producing! On one electrode(-) you should be accumulating sodium or potassium. The other should generate these dimers. The dimers have molecular weights about 1.85 (rough guess) times as much as the parent salt, assuming dimerization between identical species. It appears they are poorly soluble in the esters, but I wouldn't throw the gel away. Keep it for dissolution testing in neat diesel. I bet it is quite soluble in D2. It should make a great summer fuel.

In this reaction, the carboxylate moiety is rearranged and the + electrode evolves carbon dioxide. Do you see any tiny bubbles?

http://en.wikipedia.org/wiki/Kolbe_electrolysis

This is brilliant!

Nick,

This is an interesting idea, but i would have expected the non-polar side of BD to hold on to the 30-40 carbon dimers created. I could be wrong. It would be interesting to take some glycerin layer with soap in it and try it. The glycerin would not want to share space with a 35 carbon non-polar molecule. It might help to purify the glycerin more.

Andy

quote:

Originally posted by Liamfoxtrot:
Nick,

This is an interesting idea, but i would have expected the non-polar side of BD to hold on to the 30-40 carbon dimers created. I could be wrong.

Now as to why they aren't so soluble in biodiesel? Well you know what happens when you try to put a non polar solute in a polar solvent. Sometimes they mix if the difference of polarity isn't too large, but usually they hit a miscibility limit. I think you could dissolve some of this in warm biodiesel, but I'm quite certain it would easily dissolve in petro diesel.

quote:

Originally posted by Liamfoxtrot:It would be interesting to take some glycerin layer with soap in it and try it. The glycerin would not want to share space with a 35 carbon non-polar molecule. It might help to purify the glycerin more.

Andy

It would be. It would also be a good way to increase yields, but the glycerine would have to be free of water or it would be dangerous I would think.

quote:

It would be. It would also be a good way to increase yields, but the glycerine would have to be free of water or it would be dangerous I would think.

What dangers do you expect and why?

I recently presented my experiment at the sustainable biodiesel summit in florida, and I thought I'd throw them up here. I finished them some time ago, but never put them up on infopop, so I figured it was time.

I managed to make a continuous flow system that runs about 1 gal per minute (though it could easily be scaled up to 3 - 4) based on Graham's high voltage separation that cost maybe a couple hundred bucks. It's pretty simple and works quite well. The presentation is attached (the drawing of the design of the system is in the next 2 posts).

In the end, I think it could be useful, mostly with a continuous flow production system, however my model didn't work with our continuous reactor (though it worked great with bio/glycerin out of our batch reactor) so I was a little disappointed.

Also, Nick, I do notice bubbling around the electrodes! I figured it was methanol vapors boiling off, but perhaps you have a better explanation. I'm interested to hear more.

Greg

SBS_presentation.txt (12 KB, 129 downloads)

Here's the first set of drawings for the experiment.

batch_descriptionsvg.svg (36 KB, 201 downloads)

Here's the second set of drawings - this is the continuous system -

Also, I used Inkscape to do the drawings (it's open source), and you may have to get that program to open it up - I'm not exactly sure, but if it doesn't work get Inkscape.

Greg

continuous_point_to_point.svg (25 KB, 104 downloads)

I clicked on your two links, caustic, but only got paged full of script.... ??

I got the same thing. Download Inkscape & install, then save the file & open using Inkscape. The inkscape program is fairly easy to use (and free!).

OK, Greg, a couple of comments about your configuration (continous flow). First, how do you connect to the liquid as it flows past the two electrodes? It it simply a metal coupler separated with PVC pipe? Is it a metal mesh? I think it is important to have good contact with all the fluid flowing by, so a metal mesh in there would be the ideal method. Even a few metal mesh plates sandwiched together would cause some fluid mixing & ensure good contact of all fluid going by.

Second, as glycerin forms between the electrodes, you may 'short' them (glycerin is conductive) & make them fairly ineffective. Add a 'T' between them facing down. Any glycerin stream generated will drop into the T & not short them. You can run this T down to the bottom of your tank, just make sure biodiesel won't flow down there.

With #2 above, you can have multiple alternating electrodes. Right now, you just have Electrode1 (E1) , 10", Electrode2 (E2). Try this series: E1, 'T', E2, 'T', E1, 'T', E2, (to tank). You can connect the same E1 & E2 twice, and you'll basically get 3 times the current capability. For an experiment, for the T's just take them down to some clear tubing & a valve, & open the drains enough to prevent glycerin from filling it up. And with this method, use the same metal mesh idea from #1 above. If it does work, just loop the T drains down to the bottom of your settling tank. Make the loop low enough that the incoming pressure won't push that much glycerin & allow biodiesel through.

Does that make sense? Overall, I think you've got a good approach. It just needs some refining, and this idea with the T's is something I've been mulling over for some time. Please let us know if you try these experiments & how they work out.

-tony

quote:

Originally posted by Liamfoxtrot:

quote:

It would be. It would also be a good way to increase yields, but the glycerine would have to be free of water or it would be dangerous I would think.

What dangers do you expect and why?

Among many concerns:

Excessive conduction leading to unwanted side reactions: acrolein production or? I really don't know and haven't looked at it specifically. It was an unqualified blanket fear I put out. I'd just rather not open up new cans of worms with high voltage because my understanding is limited.

quote:

Originally posted by Caustic:
I recently presented my experiment at the sustainable biodiesel summit in florida, and I thought I'd throw them up here. I finished them some time ago, but never put them up on infopop, so I figured it was time.

I managed to make a continuous flow system that runs about 1 gal per minute (though it could easily be scaled up to 3 - 4) based on Graham's high voltage separation that cost maybe a couple hundred bucks. It's pretty simple and works quite well. The presentation is attached (the drawing of the design of the system is in the next 2 posts).

In the end, I think it could be useful, mostly with a continuous flow production system, however my model didn't work with our continuous reactor (though it worked great with bio/glycerin out of our batch reactor) so I was a little disappointed.

Also, Nick, I do notice bubbling around the electrodes! I figured it was methanol vapors boiling off, but perhaps you have a better explanation. I'm interested to hear more.

Greg

Graham reported a buildup of a powdery substance on the other electrode. If it is potassium or sodium it will rapidly react with free water and turn to sodium hydroxide and hydrogen.

That substance could be collected and tested by dipping into pure water and looking for pH change.


I'm downloading the inkscape software now so I can view your design. I've been thinking of having a custom tubular counter current continuous reactor made of glass since I learned of Graham's idea. It would incorporate this electrochemical cell using fine platinum wire mesh grids stacked vertically.

But, I'm stuck at design considerations (for another thead I guess.)

quote:

Originally posted by Nick Lockard:
Among many concerns:

Excessive conduction leading to unwanted side reactions: acrolein production or? I really don't know and haven't looked at it specifically. It was an unqualified blanket fear I put out. I'd just rather not open up new cans of worms with high voltage because my understanding is limited.

Okay. There are likely some dangers to look into like side reactions. I haven't looked into them either, I was curious if you had looked into them and had a short list of known risks. I did look into the reactions and it does look like the dimer is just one of the potential outcomes from the current. Do you have any information on the competing reactions?

Andy

quote:

Originally posted by Liamfoxtrot:

quote:

Originally posted by Nick Lockard:
Among many concerns:

Excessive conduction leading to unwanted side reactions: acrolein production or? I really don't know and haven't looked at it specifically. It was an unqualified blanket fear I put out. I'd just rather not open up new cans of worms with high voltage because my understanding is limited.

Okay. There are likely some dangers to look into like side reactions. I haven't looked into them either, I was curious if you had looked into them and had a short list of known risks. I did look into the reactions and it does look like the dimer is just one of the potential outcomes from the current. Do you have any information on the competing reactions?

Andy

Andy, no. I am just learning of the Kolbe reaction and brought that to your attention. What are the likely side reactions? Please share!

Nick,

Here is what I was referring to:
http://www.organic-chemistry.org/namedreactions/kolbe-electrolysis.shtm

Andy