Hi Jim

Seems to be. If it's dry and has no glycerol or soap, is seems to be a good insulator.

My electrostatic WVO water removal experiment did not work at room temperature.

My WVO is probably too viscous / thick at 22C. It is hydrogenated vegetable oil, cloudy throughout the test.

I will heat to 50C next, to clarify the oil, and see how the electrostatic filed compares to simple gravity settling.

More later...

Graham,

This is a great experiment. Any ideas how this would work in a appleseed type processor. It would be great if we could design something that would allow for an all-in-one unit. Use the water heater to react, boil off meth and then remove soap via electrostatic.

I don't know if I missed this or not. Did you do the glycerin settling on a batch that did NOT have the 5% prewash?

(Have you found a way to settle quickly and then remove most/all of the soap without any water at all?)

-Jim

Jim D i think the answer is yes
and yes no water
i dont do 5% wash i remove glycerin then distil the methanol off then i added the probes it seems like 3 hrs or so to settle but dont hold me to it has ive been unable to do more tests the main thing is the removal of methanol if there is a small trace it wont settle.
ive rechecked bio i had filtered to 1 micron and had a little soap from it.
will post more info when i get time to make more bio.

plugly

Hi Madmarvin

The glycerol settling looks promising for appleseed tanks, but I haven't tried it on that scale yet. Baked bean cans and coffee jars so far.

I have an 80 litre batch to make on Saturday, so will test it then.

I'll put a steel rod into the venthole, which on my tank is right in the middle of the top - ideal -

I'll insulate it where it enters with some pvc pipe.

From my 'kitchen table' tests, I am optimistic I can get good glycerol separation within 10 minutes.

WARNING:
If you plan to boil off methanol in your appleseed, make 100% sure your element is always well submerged, after draining off the glyceol volume.

You don't want any hot element surface in the methanol vapour.

Make sure you have some sort of interlock, so you can't drain off liquid while the heater is running after the boiloff.

An indirect heater would probably be a wise route to take.

--------------------------

Hi JimD

I've just replied to your PM.

I've tried with and without prewash - seems good both ways.

I am tempted to suggest no prewash is necessary with the electrostatic glycerol settling. It drops well and it drops quickly, so side-reactions and reverse reactions should be less likely. I'm hoping we can get better conversion as a result of clearing the suspended glycerol out nice and quickly.

This should also help with methanol recovery, not introducing water.

I have found that if I get the soap production low, by careful titration and with dry oil, I can leave all soap residues in the reaction tank AND wash out the filters in the next biodiesel batch, which leaves all the residue in the next batch's glycerol drainoff.

But, I did have one test batch with a lot of soap, due to wet oil, and this made my NEXT batch gel. I cleared the gel by adding a little extra methanol.

Needs many more tests before I can figure out how to do this repeatably.

Good luck!

Graham i love your thinking
ok
heres what i think
1) remove glycerin / hit with electro field?
2) distill methanol off
3) start electrostatic purification
4) drain biodiesel top down like home brew beer
5) drain soap out of bottom into filter (if left to long it ends up like jelly fish hehe.)then the bio can filter into the holding tank for the biodiesel.

or

once glycerin has been removed and the bio distilled move to another barrel for soap moving makes it easier to use reactor again.

im not sure how long the reaction takes to make the bio im thinking the time we wait is just for settling of glycerin so maybe hitting with the electro field may drop this time to minutes.

plugly

I've worked with very high voltages before (50kV up to 2MV), and high voltage does some strange things...picking paths that you might not suspect would arc. A little glycerine film on the surface or something might be enough to let just a few thousand volts arc across quite a gap.

I would be VERY hesitant to introduce any high voltage fields into an environment that is liable to have a goodly amount of methanol vapor and air, for fear of igniting it. I'd think it would be much better to distill methanol out first, *then* tinker with the HVDC. Better safe than singed...

I concur with George. Connecting a spark generator to your flammable vapor source is risky. Consider adding a very large resistor into the circuit (500K to 1Meg or so) to reduce arcing potential.

Could you use a metal plate outside and underneath the bottom of a plastic tank to draw the soap to the bottom of the tank?

or perhaps a metal bucket type arrangement that fits in the bottom of your platic barrel and can be easily removed for cleaning?

I belive air ionisiers are usually a voltage multiplier so should work on a small scale.

I have seen a lot of cheap fly electrocuters shaped like tennis raquets around the cheap stores recently. typically less than a fiver.

For larger scales I suppose some kind of custom built rig. Neon transformers do put out several kilovolts if you can limit the current. So do tv tube transformers Loptis I think they get called. There are old violet ray machines that medical quacks once used kicking around. They use an induction coil/capacitor and transformer similar to an ignition transformer. maybe transformers from kitchen microwaves? There are people out there who love to build tesla coils and spend as much effort as we do recording the results of thier hobby. Would the big green (selinium?) rectifiers from welders work to give DC from these sources?

Or you could look out for actual electrostatic seperating rigs...

This might be useful
cheapish electostatic thingy

Here's a cheap ($11) electrostatic "negative ion" (7.5kv) generator.

Hello
I am a Rig Welder in the Oil field and have 300amp DC welder that is on my truck. I will be getting some oil Saturday (if I not have to work that day) and will try to test this little theory out.

quote:

Originally posted by Redneck Veggie:
Hello
I am a Rig Welder in the Oil field and have 300amp DC welder that is on my truck. I will be getting some oil Saturday (if I not have to work that day) and will try to test this little theory out.

Low voltage, high current...the opposite of what is being recommended.

George

Yes, current limiting is vital. In my opening post of this thread I recommended...

quote:

The current passed thru the liquid is negligible, micro-amperes at the most, so there is very little power used in this process.
Safety could be dramatically improved by using a string of high voltage resistors in series with the plates to limit the maximum available current to say 0.1mA .

20 x 470K 0.6 Watt high voltage resistors in series would seem to be a suitable current limiting combination.

This was for the 1kV soap test.

The glycerol test can be done at lower voltage, with around 1mA max current limit.

I wouldn't recommend using a welder or battery charger, etc.

so what would we need to use this on an IBC type container? Hw many volts and how much current for three or four feet? and if it is only a field effect why not use plates on the outside of the conainer? With no current flow. Does make a big capacitor though. Would need a safe method of discharging it. Could be scary or dangerous.

Hi Ant.

You need the plates in the liquid, so that charge can be transferred directly to the particles / material in the oil / biodiesel from one plate to the other.

The capacitor may be physically large, but the capacitance, and hence stored charge is very low, due to the large spacing between the plates.

If you use more plates, closely spaced, the capacitance would increase, but you could then use a lower voltage.

In fact, plates seem not to be the best form.

Rather a fine mesh seems to work better, which has even lower capacitance.

As yet, I can't give you a definitive voltage / current / size requirement for an IBC, but it looks as though it can be done quite safely, with a suitably designed high voltage, low current power supply.

I am using a 1000V current-limited supply now which I can take hold of without any harm, and which won't itself create a hot enough spark to ignite a methanol/air mixture at critical explosive ratio. It can provide a maximum power output of around 0.25 Watts.

I now need to find the maximum capacitance and voltage combinations within a critical air/methanol vapour, which will remain intrinsically safe. (I do not imply ATEX 94 compliance by this, simply finding what conditions applied to a 1000V source will give rise to the minimum energy needed to create a hot enough spark to ignite the methanol/air mixture.)

I do NOT propose using 1000V in a methanol atmosphere.

The soap separation is to be done after methanol has been removed.

Water separation is to be done before methanol is added.

The glycerol settling is done with a much lower voltage, the lowest practical value of which I still need to find.

Still a lot of work to do...

REDNECK - using a welder will produce no noticable filtering effect. I have tried low voltages up to 60 volts DC - higher than your 300 Amp welder supplies - with NO noticable effect from many hours of filtering and approx. 2 mm plate separation. Go put a volt meter across your welder terminals - it will not come near the high voltages necessary for this electrostatic effect. What you need is 1000 volts (maybe more), not 10 or 100 volts, and .1 amps, not 10 or 100.

High current, an inadvertent short, and you'd have a nice bar-b-que. Don't do this, we've had enough biodieselers burn their house down. That said, anyone with much welding experience has probably already inadvertently caught themselves on fire with sparks, so, if you cook yourself with biodiesel, please survive enough to post some cool pics

Graham,
1st of all thank you..... next, do you think this concept could be used as a basis for FFA reduction?

I have tried electrostatic glycerol separation on biodiesel made with new sunflower oil, to see whether fresh feedstock affects separation speed.

I used 1000V , current-limited to 100 uA (0.1mA)
and the separation was rapid.

The standing current during this test was around 4 microamperes. (4 milli-watts of power, or 0.004 W)

2 core solid wire, ends stripped back 2mm.
+ wire end on bottom of glass.
- wire end about 50mm up from bottom in middle of liquid.
Liquid depth around 120mm.

Here is a table-top-video of the separation.
My estimate is that I had 80% separation within 15 seconds. Full separation within 2 minutes.

This is a similar settling speed to that I saw when I did the same experiment with used-oil, titrating at 1.5g NaOH + base amount.

Recipe:
1 liter new sunflower oil
220 ml methanol
5g NaOH
no prewash

http://www.graham-laming.com/bd/nr.htm

By the way, finished sunflower biodiesel smells really nice - reminds me of something tasty I must have had as a kid, but I just can't remember what it was. A little like vanilla, but not vanilla.

This message has been edited. Last edited by: GrahamLaming,