Keith, What I am referring to is when you stop mixing with the pump to let the BD settle out the BD in the pipe above and in the pump would also have it's Glycerine settle and with the pump horizontal there is a low point in the vane which I would think Glycerine would settle. That Glycerine would not be drained off and when the pump was switched back on it would mix back in with the BD.
By vertically mounting the pump (and above the Gly level) there would be a flow through advantage and the settling Gly would move through the pump and would easily be removed with an addition of a valve at the base (low point) of the plumbing or if designed right flow back into the reactor and removed with the rest of the Glycerine. Because I have not done this before and do not have a processor built I am not sure if the amount of Gly I am talking about is sufficient enough to worry about. However I would like to be able to remove as much GLY as possible from the BD. My pump is a Clear Water one basically the same as you have been referring to and really! if this pump will run vertically I will mount it vertically. I was thinking on getting a Hot water heater for the reactor however the drain point to pump is at the base. You wrote that that point should be further up the side of the reactor. What are you guy's thoughts on this? Does Girl Marks processor work well? What is the best reactor? I want to make one that will do me for years and make high quality BD. Basically I want to get it right from the beginning. PeterR -----Original Message----- From: Keith Addison [mailto:[EMAIL PROTECTED] Sent: Wednesday, 10 March 2004 7:09 PM To: biofuel@yahoogroups.com Subject: RE: [biofuel] biodiesel mixing Hello Peter >Keith > >Wondering if the Clear water pump should be mounted vertically Not quite sure what you mean, nor if it matters, but ours and others I've seen pictures of have them mounted horizontally, with the inlet at the front and the outlet out the top. >and above >Glycerine? > >So that no Glycerine settles in the bottom of it. I don't suppose that would hurt it. Maybe if you use NaOH and the glyc solidifies it might make it hard to start again, but I doubt it. Anyway, I get the idea that the level of the mixing tank outlet to the pump relative to the bottom of the tank is quite important. With our processor (it was previously a kerosene tank, with a convex bottom shaped for optimal drainage) the mixing outlet is set somewhat higher than the level the glycerine by-product cocktail will settle at. That level will vary somewhat according to the oil (and process) you use. Now, there's no agitation in the tank, just circulation - the oil doesn't gush back in at the top in a solid 3/4-inch-thick river to plunge into the top of the oil and splash all over the place, it's gentle, no splashing. All the agitation as such takes place inside the pump. The pump pulls the oil in from the tank outlet, but that's not very violent. As a result, a lot of the glyc cocktail settles out during the processing, which is a Good Thing. I think about half of it settles out before the processing's finished. This does also remove some of the methanol, which is dissolved in the by-product. Aleks Kac's two-stage acid-base process has an optional step of draining off some of the glycerine during the base stage. ("The process runs fine without it," he says. "It's just a twitch to get higher yield" if your processor has a bottom drain.) He said this about it: "The process is running on the smallest sensible volume of alcohol. While removing a small portion of it with the byproduct would seem to slow the reaction down, the rather large mass of removed byproduct will tip the scale toward ester production." We find that's the case - the settled out glyc by-product more than offsets any methanol removed, with very satisfactory results overall. So this could be a consideration in setting the height of the tank-to-pump outlet. To test it, I attached a right-angle elbow to the inside of the outlet (inside the tank), pointing up, so the pump could only draw from higher levels of the tank, not taking in any of the settled by-product. This didn't work as well, so I removed the elbow. I wouldn't want to set the outlet any higher in the tank, nor any lower. I said above that about half the by-product settles out during the process, but I think much more than that does, but some of it is constantly being recirculated (along with its methanol content), and this seems to be about optimal. I tried to figure all this out in advance before building the processor. Presuming about 100% production (which we get, using an acid-base process as standard), and 20% total methanol v/v WVO, the amount of by-product will be 20%, or close to it. So if the depth of WVO being processed in the tank is, say, 100 whatevers, the total depth of by-product that will eventually settle at the bottom will be 20 whatevers, or close to it. I decided to centre the tank-to-pump outlet (1" OD) at 30 whatevers from the bottom. It was kind of random - I didn't know how much the pump would pull nor quite a lot of other things, but by dumb luck it seems to be about right, I don't want to change it. This might not be very useful though - that works for the Harbor Freight 1" clear water pump with this particular size and shape of processor. FWIW it's a 90-litre tank, the diameter is 17.5 inches (44.5 cm) and we process 60-litre batches. (There's also a holding tank and two wash-tanks, which effectively doubles the capacity. We didn't want a bigger processor - this one's a useful size and the processor and one wash-tank can easily be loaded into our van so we can take them to demos and so on.) HTH - best Keith >PeterR >-----Original Message----- >From: Keith Addison [mailto:[EMAIL PROTECTED] >Sent: Tuesday, 9 March 2004 6:16 PM >To: biofuel@yahoogroups.com >Subject: Re: [biofuel] biodiesel mixing > > > > >My question to the group involves a 55 gallon drum used as a > >processing tank. If the mixing shaft were to be lowered straight > >down into the center of the tank, would adequate mixing take place? > >Or would a vortex form in the mixture and inadequate mixing take > >place? I see some tanks have the mixer angled on the side of the > >drum, I'm assuming to avoid having a vortex form. Would baffles > >along the inside of the drum help? Thanks. Jonathan. > >Yes, baffles would help to increase agitation, presuming you know how >much agitation you need. > >Why would a vortex mean inadequate mixing? Chuck Ranum has his mixer >set at an angle from the side but still talks of a vortex. If the >mixer turns fast enough you'll get a vortex whatever angle it's set >at. How far down does the vortex go, all the way down to the mixing >blades? Perhaps that would be too much, but the answer would be to >decrease the speed or the angle or size of the mixing blades. > >Anyway, Jonathan, why not use a pump instead? Aleks Kac did some >research on this and told me this: "As a rule of thumb you need 1000 >W of shaft power for pump stirring on a 1000 litre/batch reactor as >opposed to 3000 W of shaft power for turbine stirring for the same >volume." I think pumps work better than stirrers, and it's a lot >simpler to build a closed, fume-free processor with a pump. These 1" >Clear Water Pumps are cheap and reliable, and work very well. > >Harbor Freight Tools -- 1" Clear Water Pump -- Item 1479-1VGA >http://www.harborfreight.com/ <http://www.harborfreight.com/> <http://www.harborfreight.com/ <http://www.harborfreight.com/> > > >Northern Tools -- Cast Iron 1in. Clear Water Pump, Model# 109955 >(Warning -- very BAD at dealing with international orders!) >http://www.northerntool.com/ <http://www.northerntool.com/> <http://www.northerntool.com/ <http://www.northerntool.com/> > > >Northern Tool & Equipment Co. (UK) Ltd. -- 1" Clear Water Pump, Item >No. 109955E >http://www.northerntooluk.com/ <http://www.northerntooluk.com/> <http://www.northerntooluk.com/ <http://www.northerntooluk.com/> > > >Best > >Keith Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html <http://journeytoforever.org/biofuel.html> Biofuels list archives: http://infoarchive.net/sgroup/biofuel/ <http://infoarchive.net/sgroup/biofuel/> Please do NOT send Unsubscribe messages to the list address. To unsubscribe, send an email to: [EMAIL PROTECTED] _____ Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/biofuel/ <http://groups.yahoo.com/group/biofuel/> * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> * Your use of Yahoo! Groups is subject to the Yahoo! Terms of <http://docs.yahoo.com/info/terms/> Service. IMPORTANT: Notice to be read with this E-mail 1. 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