The transfortmer is most likely 2kva at high amps. It will kill you in a (stopped) hearbeat. Be very very careful. use current limitation. If you dont know what that is or how to do it then dont use your transformer until after you learn it well.

Not sure how I going to achieve the current limiting.

which side of the transformer is best to setup the current limiting circuit.

is it better to do.
run an ac power supply to the transformer and then convert the high voltage DC

or

Just send high speed DC voltage pulse to the transformer

Hi Cover,

This post may help ...

http://biodiesel.infopop.cc/eve/forums/a/tpc/f/71960555...091059761#5091059761


Hope that helps.

Hi Graham

Could "regular" 220v/50Hz be used for a glycerol separation cell?

Hi Yair,

Yes it can be used, but again, you'd need some way to limit the current, as in the above post.

The plate spacing would need to be around 5mm I guess, and the plates should not be allowed to enter the settled glycerol.

Hi Graham
I decided to test it.
I mixed some ready2use biodiesl with glycerol.
poured it into a 1.5 liter soda bottle.
took an electric wire , separated the ends (about 10 mm of copper visible, with about 30mm distance between them). shoved it into the mixture.
and..... the glyc just plummeted down.
so I guess the problem now is limiting the current...

did you ever test to see if all the glyc were being settled, even the bit normally held in the meth?

No, I didn't test.
It was just a Go/NO-go for regular 220v.
My intention is to speed the process, so even if it only precipitates 80%-90% of the glycerol within the hour (instead of overnight) then it should be good enough for stage 1 of a base/base (I add a 3'rd stage i.e. Base/Base/Base to ensure full conversion)

Is it possibe to power the transformer by a current source rather than a votltage source.
Mean that current will remain fixed but voltage will change depending on load.

I would use a circut like this
http://www.aldinc.com/pdf/cs_11001.0.pdf

Graham,

I just re-discovered this thread.

A comment on current limiting. It's a waste to try limiting the current on the high-voltage side. Yes, possible, but expensive/dangerous. Do a simplier route: limit the current on the lower 120v/230v side.

A simple example. Let's say you have 120v, a 10:1 transformer, and want to limit to 10 mA for your 1200v output. OK, then then 10mA will translate into 100mA on the other side (120v) of the transformer. This is simple conservation of power (power = voltage x amperage, so 1200v x 10mA must equal 120v x 100mA, less a small inefficiency factor). So, you want to limit 120v to 100mA. R = V/I, so 120v/.1A = 1.2kOhm resistor. Just for safety, I would recommend two 600 ohm resistors, in case one failed. It's the old UL test guy in me, you want to protect the user in case a single component fails.

While I'm at it, let me make a suggestion for anyone who has a transformer & don't know what it's turn ratio is. Take four power resistors, and put one on each of the 4 wires. Decent resistor values, maybe 1k or larger (not critical). On the side that was previously attached to 120v/230v, just tie the two resistor ends together. On the side that was the output, wire to your 120v/230v supply. Obviously do everything with power off, protect yourself, etc. If you don't know anything, extend your life & don't do this. If you do, then take an AC voltmeter, and measure the voltage across the two output resistors that are tied together. If you have 120v and it reads 12v, then it's a 10:1 turn ratio transformer. It it reads 1.2v, it's a 100:1 transformer. If it reads 6v, it's a 20:1 turn ratio. Got it? So, the simple explanation is that you are going from high-turn to the low-turn side of the transformer, and it is lowering the voltage which you can easily read with a voltmeter. Most voltmeters cannot read 1000v, and you endanger yourself trying to read it.

OK, onto some thoughts. Electrostatic works great for glycerin separation (quickens the process), and also for water separation from finished biodiesel (again quickens the process). It even works for helping to remove soap from post-methanol-removed BD. Is anyone now using this process in the larger batches?

This thread seemed to die, I'd like to revive it!
-tony

thanks for that useful information

There has been some discussion about how to run the terminals.

I've got an idea, from Graham's site. Let's say you take a section of plastic tubing. Insert a couple of stainless steel mesh material, like used for dish scrubing. Actually, the same material as Graham listed for helping to blend the WVO & sodium methoxide. Put a screw through the plastic tubing to make electrical contacts to each of the mesh materials, making sure that the two meshes will not touch each other. In fact, you might want to put a section of cotton or something to make sure the two sections stay apart (but just a couple of inches). Attach the two screws to the two voltage terminals, and protect them from accidentally shocking you.

What will happen is that the blended Bio/Gly will get charged in the first mesh, and get the opposite charge as they go through the second mesh. It may require that there be more than one alternating terminal mesh materials, but the glycerin should clump & drop as it goes down.

Having a clear tub will help to see how well are things separating. I'll have to make sure the screws don't leak. It might also help to put the tube at maybe a 20 degree angle downward from horizontal, to allow the glycerin to ooze on down.

Obviously you will need to prefilter otherwise this section will get blocked up. Safety will also be an important item to check.

Thoughts? I still need to find a transformer. Anyone have a setup where they can do this experiment?

-tony

Greetings All,

I have been trying to follow this thread for using an electrostatic separator for esters/glycerin, dewatering, and soap, but there are many insightful discussions, changes, and tests underway and it is a bit hard to follow.

Although, I am still learning a lot and have only been getting involved in Biodiesel for a short time, I am extremely excited about the whole topic.

I am wondering if anyone has compiled a (current) simple and basic design of a electrostatic separator that they have working?

I am interested in how this process compares to others like a centrifuge (since a centrifuge is very expensive) and if anyone has been able to produce some biodiesel that can pass the ASTM D 6751 standard with this new approach.

It seems to offer a great potential and I would like to get involved if I can.

Hi Lonnie,
I havge built an electrostatic coalescer, im yet to test it but Im confident, glycerin ester separation at low reynolds number is no big chalenge some plants simplyu use a plate impingment coalescer. ( please excuse crap spelling). I think that this aspect is less of a challenge than the ascociated automation control to make it truly continous and automated.

electrostatic and variuos types of impingment coalescers have been comonly used for many years in the petroleoum industry.
Regards
Tim M

o give us some pics and details of yours Tim?

Where can I post pics? last time I tried it hear it did not work, it seames at the time that external hoasting was required. GL kindly posted a pic opf my oscillator a while back. if you send me your email I will send a pic when I have one. the glass bit is done But I have not had time to turn up the clamp that connects the glass bit to seperating tank yet.

Running my day to day buisness is an unfortunate necessity.

Regards
Tim

Can somebody point me to a transformer that is safe enough for me to use for glycerin separation.

I am not capable to perform current limitting myself.

Thanks.

Ppusopa,

If you CANNOT do the current limiting safety part, then you MUST NOT work with this.

Let me try to explain the problem. IF you do not limit current, then the 'current limiter' will be your breaker box, and it will not just blow the breaker, it could cause an explosion and KILL YOU.

Am I making my point? Note that many people were talking about fairly complicated ways of limiting the current on the high-voltage side. I do not believe that this is completely necessary. If you limit current on the low voltage (120 or 220v side) side of the transformer, it is much easier.

Here's an example. Look at EBay item #180139174265. It puts out about 2100v from a 120v input. So it is about a 17:1 turn ratio transformer. Let me assume you want limit the 2100v to 10 mA (you need to determine based on your setup both the voltage and current you need). You should start with lower voltage and current, and increase to where it performs in the timely manner you need. But, back to this example. 10mA at 2100v will translate to 17 times the current at 120v, or 170mA. On the 120v side, that means you need (120v/170mA) 700 ohms. For safety reasons, I would recommend using 2 resistors in series of 350 ohms each. The reason is that if 1 resistor fails with a short (this can and does happen), you still have current limit even though it will be twice the current (ie should avoid an explosion).

Also, note that these resistors need to be of sufficient wattage. You will have 60 volts across 350 ohms. P= V^2/R = 60^2/350 = 10.2 Watts. I would recommend they each be a 20 watt resistor as you'll be running these for extended periods of time. You CANNOT use those little 1/4 watt resistors.

Also, again for safety, I would recommend at least 1 current limiting resistor on the output side of the transformer. Again, a safety factor.

Again, I can't say this enough: THIS IS A DANGEROUS CIRCUIT AND IF YOU DON'T KNOW WHAT YOU ARE DOING, THEN YOU CAN KILL YOURSELF AND OTHERS.

If all you want is a transformer rated for these higher voltage, I give one example above. But you need to understand the basics of V=IR (voltage =current x resistance) and P=IV (power = current x voltage).

How about some better advice: if you don't have any experience on this you should go to a local electronics shop & have someone there solder together a setup for you. It shouldn't be that expensive, but what value do you put on your LIFE!

-tony

TexusTony,

Thanks for the reply.

I have read the entire thread and concluded that
this stuff is dangerous. May I should have worded differently. I wanted a recommendation
as to what device is "the safest" to use for experiment with KOH, giving that I am not electrical engineer. I am sure there are a numbe of people on the same spot as me. I have time and $(?) to experiement and will be happy to report result back. Just need somebody to help me started.

I was looking at serveral devices mentioned in this thread, but I can not make decision.

1)The Fence Energiser
2) Negative Ion Generator
http://www.goldmine-elec-products.com/prodinfo.asp?number=G1783
3) DC power supply
http://jlnlabs.imars.com/lifters/labhvps/index.htm
All of these appears to be relatively safe as far as I can tell. I don't see anybody reporting back result with this kinds of device.

Thanks.

PPusaopa,

Of your 3 choices, none really jump out to me as an ideal product. On the fence chargers, I'm not sure what voltage they put out, but at least they are safe as they limit the output energy. But not knowing voltage & amperage, it is hard to know if it will be sufficient.

Option 2: I'm not excited about this. It doesn't show any current limitation protection, it only puts out 7.5kV (which is a bit high for most setups), and it doesn't show a return current path (I can only assume it returns via ground, and that's far from ideal.
Option 3: Of the 3, I like this best. But it looks to me like it's a recommended circuit. I didn't see where you can simply buy the unit, and if you can assemble/solder that board, then you don't need my help. I very much like that it lets you sweep across voltage to see what would work best for you. He also mentions that you should add current limiters in the circuit, but that basically takes you back to our simple transformer+resistor circuit. Only big advantage is that it lets you sweep voltage, otherwise it's the same.

If someone said that they had basic skills, I would recommend buying a 1-2kV transformer (step up from 120v), and wire it through a couple of high wattage resistors into a power cord (for the 120v side). Add one more power resistor to the output side, and wire that to your setup. Remember, the output side will require better voltage isolation (many wires are 600v insulation rated, so that's an issue to be careful with). It might be better to place the transformer near where it'll wire into your setup, to minimize this risk. And always have a switch on the input voltage (a power breakout adapter with an off switch would be fine), so that you can quickly power off this unit in case of trouble.

Just my opinion... by now everyone should have read that this is a dangerous activity.

-tony