I don't see why you couldn't use a Venturitype vacuum eductor for this.
just pump your oil through the supply port (big fitting) and connect the vacuum side (small fitting)to your Meth line. Put a small needle valve in the Meth supply line and you're set.
Vauum eductors are available in many different sizes and materials
Has anyone tried this?
An eductor would also be a good way to increase the mixing action of a small pump in a bigger tank.
mathematical elegance -- desired result achieved with minimal complication
i have my switches located halfway up the shelf for the stand that i was going to use for methanol holding would the sparks generated by fliping a switch set the methanol off even though its 2 feet away 3 feet above under a vent hood?.. im not putting it up there but on a chair next to the processor
probably work just fine but, again, why make a simple system more complex ? Up to a reactor size of 40 - 50 gallons the cheap harbor freight pump works fine and will pull your "methoxide" from below the pump level
at a perfectly adequate and adjustable rate.
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I am still sticking with my itty bitty aquarium air pum connected via a Delrin Sleeve into the vent cap of the carboy. This does NOT use clamps as the air line fits snuggly enough without it. Should pressure build up inside the carboy then the weakest point would let go and this is the connection at the Delrin Sleeve where the aqir line connects. It pops off, the air pressure is relieved and the "problem" goes away.That is worst case, and still safer than leaving the vent cap open all the time to compensate for the liquid leaving the carboy so a vaccum isn't created inside the carboy as the methoxide is being sucked out by the pump. With a check valve installed and no vent cap open or "some" way of compensation you would be sucking the carboy into collapse while methoxide is still in there,a gain a whole whack more dangerous than anything I am doing with a pop-free connection hooked up to an aquarium air pump. All I know is that it works, and works well for me, and I don't forsee any explosions due to this set up at any time soon. I would be more cautious of an open-to-the-air vent cap hole than what I am doing.
** Biodiesel Glycerine Soap - The Guide
- on 5 continents helping people make & sell soap from the Biodiesel Glycerine.
I believe some are connecting the carboy vent to the HWH vent, so that pressure is equalized. Seems like this was mentioned in different thread, where Girl Mark did some tests on what pressure was achieved in an unvented processor.
Once the methoxide is fully mixed in, would the vent to the carboy need to be closed to prevent processor tank pressure in the carboy?
Hmm, another thought, could a condensor be incorporated in between, such that vented methanol gases would condense and drain back into the original methanol container? Suddenly my mind is overwhelmed with visions of a tangled mass of plumbing.
So does this count?
Do I win any points for creativity?
has anyone tried to determine the ratio of oil to meoh for a mixing rate?
for example, I use 230l of oil, 26l of methonal + KOH as needed. How long should it take to empty my carboy of meoh? 20minutes, 40 minutes, an hour or more. I using an 1.5" Northern tools clear water pump for mixing. I can adjust the oil and meoh rates?
I have made several batches( 12 and counting )
the reason I ask...The next to last batch I mixed at a slower rate the previous batches. the washing seemed to go easier (ie fewer). Also the cloudy point was the lowest I have seen. somewhere less than 35F.
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everything run B100 when its warm enough
Um yeah now I know why Harbor Freight had that clear water pump on backorder :-)
I am reading this thread as I am redoing my carboy setup. My original design was only about a foot above the pump and would have worked great, except somebody welded the platform on the legs wrong! Anyway, dkenny, you may be on to something as the last batch I ran turned out about the same as yours. I gave up at 37f in the freeze and still looked great. Looking back through the records for that batch I see there was a little tussle getting the methoxcide to go in. I think my check valve was being lazy. Anyway, it took a lot longer to introduce the methoxicde than on previous btaches. So like I suggested, you may on to something.
And as for my carboy rack redesign, it will be above the pump but still only about 12" off the ground. I am going to do a double stack with plumbing and valving tying them together.
Oh and Graydon, you need to call New Orleans, they were looking for some pumps! Jeez!
Have them get a hold of me...I'll make em a whale of a deal...
The best way to vary the flow rate of any fluid through a centrifugal pump is to use a discharge throttle valve (i.e. globe valve (ex: a water faucet valve)). All the valves that I've been seeing in these processesors have been ball valves - which, do not make very good throttle valves.
Sorry for skipping through a bunch of this thread, someone probably has already beaten me to this.
Next: As far as carboy placement height - As long as the pump doesn't start making a bunch of noise, then the height of the carboy really doesn't matter too much. Higher placement gives the pump more NPSH (net positive suction head), but as long as the methoxide is fairly cool on the pump suction side, you should not have to worry about pump cavitation (which affects both life of the pump as well as its performance).
sorry to blob on,
Dogma: I believe that the main cause for concern for having the methoxode up high is the risk that it may be spilled into somebodies eyes/face.
It would seem to me that if you wanted true control you would design the system so that the Methoxide was injected at the proper flow rate in relation to the oil flow rate. This would require many hours of research to find the optimum flow rate for the perfect reaction. I would be game to work on this study with a few local students and a grant, I think I will approach my local school about this.
Amazing how something so simple can be so easily overlooked.
How would you modify a Half Beer Keg for pressurized methoxide injection? I am working on a drawing and I am not really familiar with the layout of a half beer keg. I will know better when I get them today (free BTW). Just called my local beer distributor and bang offered 1-2 for free. I love free. I am picking up 4 free 275 gallon oil tanks tonight also and trying to contact a local homeowner (rental unit) that had 5 40 gallon water heaters flooded and the insurance company is paying to replace them (possible freebies). Back to topic (sorry) if there are any examples of where this has already been done I would like to see them, as I would like to create a reactor that will last and provide non tinkering performance across many batches (I do realize that with WVO I will have to do some tinkering). Thanks in advance.
Amazing how something so simple can be so easily overlooked.
Graydon, love the pile of pumps, how much to ship one or a few to Australia? Slow boat will do fine.
PS You need another sticker for your great collection:
Biodiesel - This car is cleaner than a Prius!
Highly poisonous and explosive Methoxide squirting all over the place in case of a mishap?
You better think about that!
(Mark puts up her post about warning people NOT to put the carboy w/Methoxide far above pump level to avoid mishaps and you are planning to pressurize your container?)
I noticed on my last batch while doing the glycering prewash, I use the same port for water as methoxide, I did not open the vent on the processor and it seemed to suck in the water even better than when the vent was open for the methoxide injection. Next time I'm going to try leaving the vent closed for methoxide and see what happens, that way I won't loose any methanol to the atmosphere. I'll let ya'll know how it goes. My carboy is usually below waist height, sits on top of a 5 gallon bucket.
Great topic girlmark!
We use a venturi on the Wilson College processor. Yeah I guess I don't need it and will leave it out of the appleseed we are planning to build, but for the sake of the forum here is my experience...
Mazzei Injector Corp (google them) sold me a venturi based on the flow rate of my pump and the line size we are working with. It was about $50 or so new, they have a variety of sizes made from hard plastic, used for fertilizer injection, etc. The Mazzei venturis are sold with a spring loaded check valve installed. We added a small plastic inline valve from US plastics to the methoxide line.
This thing works great. We always keep the 15 gallon carboy we use for methoxide on the ground. Once the processor is full of oil (50 gal) we recirculate the oil through the venturi and as soon as we crack the little valve it starts sucking methoxide. There does seem to be some mixing in the venturi. We also use the venturi line for drawing up water when doing glycerine prewash, or sucking in random bits of biodiesel that we want to run through the outlet filter a second time.
There is a half decent picture at www.wilson.edu/fcsl click on the biodiesel link. I have to admit we pirated some of this design from a guy named Jedi who used to post here back in 03. We have had some problems with the rigid plastic tubing (not the venturi), and yes Mark you can overheat a plastic tank (!) but we try to avoid that
The pump to ship to Australia would probably run near $40-$50 bucks. You'd be better off lookin' for something local. Dang things are so heavy that they really knock the shipping cost up.
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