Graham Laming started an interesting thread on Electrostatic-field purification of unrefined biodiesel over at Infopop. He's had success dropping suspended glycerin out - check out this video. I know he's been working on soap removal as well. I think this is very interesting, and I'm wondering how to best apply the concept to the production scale whilst maintaining safety. Ideas...?

ebztz:

Graham Laming started an interesting thread on Electrostatic-field purification of unrefined biodiesel over at Infopop. He's had success dropping suspended glycerin out - check out this video. I know he's been working on soap removal as well. I think this is very interesting, and I'm wondering how to best apply the concept to the production scale whilst maintaining safety. Ideas...?

That is *very* interesting. I'll have to think about it some.

I thought the same. I wish I was back in school with a well-stocked lab and machine shop so I could experiment with this type of thing.

Hey Mike,

Any suggestions as to how to experiment with this process? My understanding of E&M isn't up to snuff, but I'd really like to study this as seems incredibly useful. 

ebztz:

Hey Mike,

Any suggestions as to how to experiment with this process? My understanding of E&M isn't up to snuff, but I'd really like to study this as seems incredibly useful. 

Essentially it works similarly to electroplating. You apply a voltage across the two immersed plates, which essentially means one plate is positively charged relative to the other plate. The result is that charged ions in the fluid are attracted to the oppositely charged plate. I'm not sure offhand though why glycerin would be attracted to either of the plates (soaps though are likely fairly readily ionized in the presence of the electric field between the two plates, and then become attracted to one of the plates, where they will clump up and settle out. The settling out of the soap may in some way facilitate the fallout of glycerin). I would make sure though to only try this on demeth'd biodiesel.

 Being kind of lazy, I thought, "what if it's just the electric field causing the polar fliud to increase it's self-attraction / exclusion of non-ploar fluid" ... ie what if the electric field increases the rate of glycerin drop size growth (not really directly related... but lazy/hopeful...)

So I put some in the microwave... wa-la I think it accelerated the separation.

Search google for "electric fields emulsions" -not in quotes in search and you'll find things like: " Electrodehydration and electrodesalting of crude oil emulsions" and " Electric-field emulsion-breaking device"

So... continuing: since the above references are about emulsions rather than what the BD/G mixture is (since it settles, it's not an emulsion) I thought what's a mu-wave gonna do to an emulsion... NOTE: being a NUBE and a RUBE, I've made some remarkably stable emulsions. They partially break with addition G-layer but the residuel emulsion is multi-day stable... unless I put IT in the microwave.

Just before boiling (so by other experiments maybe 75-85C) it fairly rapidly separates into 2 layers, top = BD looking stuff, clear... bottom layer = emulsion.

Question: Does any body have an idea what the quality of separation is at this point? For instance, though I don't have a lot of reproducibility, this BD layer produces fairly clear water and fast settling when shake-washed.

 Well, I should have looked/known:

http://www.biodieselnow.com/forums/p/5205/37729.aspx#37729

near the bottom... "to break emulsion, heat in a pan to about 100C" -BB

 

hmmm, that link doesn't work. It should have led to about the 5th result of a search here on "emulsion":

• Re: Ethanol instead of methanol

  Hello 3rd_shift Congratulations on your first batch of biodiesel. Did you use the World Famous Dr pepper Wash Technique (Pat Pend) to wash it? To break the emulsion try putting it into a small pan and heat to just below 100deg ...

  Posted to Advanced Biodiesel Production Methods (Forum) by Billy Bob on 09/21/2005