Hello Doug, I have been asking myself the same question. I got busy this week but I wanted to go a friend of mine who is a chemical engineer. I want to show him and present the question to him. Why does this work so well?

My gut instinct on this is that it is removing methanol below .2% and then the soap just so wants to drop out and it gets stuck to the wood. (That decimal point I am unsure of because someone is using a breathalyzer to measure methanol content and I am unsure what scale they are using) Regardless, it appears through Graham Lanming's research and those using the breathalyzer, that when you get below this point, the soap does just drops out regardless of wood chip filtering. I have never experienced this myself yet even though I am using the push/pull process because of either one of two reasons: 1) I am using Koh and that is an un-researched variable or 2) I have not got lower than the 2% yet. Because of those using the breathalyzer research can get their Bio to just drop soap, I am beginning to suspect more and more that is the way to go. Which is why I make this connection to this thread. Am I right? I could be but at the same time, still just a guess until we have some real testing. I think I need to buy a breathalyzer and run this methanol test before and after wood chip filtering to see.

Doug

This message has been edited. Last edited by: Doug Weiner,

I am sure if you drive off the methanol and just let the BD sit the soap will fall out. The factor here is time. Time is the one thing I do not have the pleasure of owning. No b%tchin, that is just how it is. I have a machinist bud of mine and I intend to give him the dimension for the venturi. When he is done I should be able to take the old pipe out and use two junctions on either end of the venturi to put it on. With recovering the bulk of the methanol and running through the chips I should be able to speed up the process. I have to make 300 to 400 gallons a month to stay away from the dino pumps. I can't brew 80 gallons and wait for the soap to fall out. I need to push it out as fast as I can.

Doug,

I think Graham in the GL-1 write-up states that the soap settling process doesn't seem to work as well with KOH. I am sure the soap settles out of the BD, but it is not as obvious as in BD made with NaOH.

I look forward to the results of your testing.

Doug,

Generally you have the right data relative to methanol removal and biodiesel's immiscibility with glycerin and soap. Fortunately the glycerin is a great scavenger of other undesirable elements, as well. We found dropping glycerin through fluids was a great way to knock done total particulate count - this is why some original work with biodiesel production (Van Gerpen) said filtering to <100 microns might not be necessary because once the glycerin is produced in the reaction process it will strip out particulate matter during the settling process (note however this same particulate matter can be primarily starch and in this case not filtering can be disasterous since these kinds of particles can hold excessive amounts of water and other side reaction problems).

Anyway the wood fibers have a capillary action which tends to trap the glycerin and the glycerin in turn traps the soap. Additionally if the biodiesel does have a low methanol content then the soap naturally becomes slimy and stringy and the wood sawdust/chips act as a mechanical filter (which is why we really like the sawdust or Eco2Pure in our process because we use it as a serious contaminate KNOCK down media and don't rely on it to produce ASTM fuel).

Methanol content is still the tricky element in this though since methanol isn't really being removed - like resins it may trap some finite amount but it isn't a lot and as the methanol passes through, it will take dissolved soaps the most readily - right through the bed of sawdust; that is unless there is sufficient quantities of glycerin already adsorbed in the wood fiber capillaries.

GCG

PS did Jehu say BUTT ... HEH HEH HEH