quote:

Originally posted by RickDaTech:
Video of the eductor in action. This is unwashed biodiesel with the methanol removed. It has not had enough time to settle out the soap. It's a big 3.8Mb Widows Media file.

http://kitchen-biodiesel.com/eductor_video.htm

Any way for you to reformat that video to an open source format so those of us not running Windows can see it?

I can try. I have limited software for editing video.

http://kitchen-biodiesel.com/realeductor.htm

Try this one. It's a lot lower quality, but it's the best i can do for now.

quote:

Originally posted by RickDaTech:
What is a "roller pump"? We still have a few slots left open.

It's a pump, that has a set of rollers in a cage, in a housing that are turned by a motor, and they pull the fluid through the housing. See here: http://www.delavanagpumps.com/roundup/works.html

It is a fixed displacment pump, meaning that if there is resistance down the line, it builds more and more pressure, where as the HF pumps build pressure to a certain point, then just stop building pressure. My pump can move about 20 GMP, as I have it set up now. My 3/4 static mixer caused enough resistance that it bogged down and overloaded the 2 HP motor that I have running the pump. I am curious to see if the eductor does the same thing.

RedLance,

Do you have a pressure gauge you and use to check the head pressure before the static mixer?

Try this: Hook up the output of the pump to a braided hose so you can pump into a drum or bucket. Then on the end mount a 1/8" x 2" pipe nipple like discussed here. If that boggs down your motor, so will the eductor.

I have one that goes to 100 psi. I'll plumb that in and follow it with the static mixer, and run some hot oil through it, and see what happens. I'll also try the 1/8" x 2" pipe.

Someday, I'm going to get a borescope, and look inside my reactor to see what it's actually doing, as I have a feeling, that with my pump, I don't need any more agitation.

http://en.wikipedia.org/wiki/Borescope
http://www.fiberscope.net/

quote:

Originally posted by RickDaTech:
http://kitchen-biodiesel.com/realeductor.htm

Try this one. It's a lot lower quality, but it's the best i can do for now.

Thanks, that works for me. What are you observing with the eductor? More fluid movement from the exit point into the tank? It's an intriguing device...

What I'm observing is increased liquid motion in the tank. Dumping the oil/bio over the top of the tank through a 3/4" outlet does not cause the liquids in the tank to move significantly.

Eductors are often called "mixing eductors". They start with the flow being pumped or motive and take it to a high velocity using a nozzle. When sprayed into the liquid it will suck up to 5 times as much liquid in the tank and mix it in the diffuser so the flow out of the diffuser is 5 times greater than the the motive flow out of the nozzle. So what we get is actual mixing inside the tank as if we were using a paint stirrer on a drill. With pump mixing alone we do not see any mixing inside the tank and for maximum efficiency must use a high volume (high power draw) pump to turn the oil over faster than it can separate. With mixing inside the tank, it appears as if we slow down the rate of separation inside the tank and lets us use a smaller pump.

The goal is to have enough mixing inside the tank so that we can introduce the methoxide quickly in an appleseed and still be able to make high quality biodiesel.

more explanation of eductors here

REDLANCE

I would see about getting a bypass assembly for that pump or never run it when you are away. Non Bypass pumping systems must be operated w/o restriction for the reasons you mentioned. As long as the motor breaker will always pop you have that safety but if it ever just stopped and did not pop you could have a problem that Tilly would want to write about.

Aside from that let me know how it works, I have never done destructive testing on one of theirs.

Redlance,

Doug is right. Macmaster and Carr sells some bypass valves AKA pressure relief valves that will work for the job. The SVO guys are using them on their centrifuge system and probably have part numbers listed for them.

Another way to do it is to put a TEE in the output before the static mixer or eductor with a valve on the TEE and with the output dumping back into the tank. Mount a pressure gauge in between the valve and the TEE. Start with the valve open, as you close it the pressure will rise. If you have all steel, I would not go above the recommended max pressure for the pump. If you have any plastic, like a plastic static mixer, I wouldn't go above 50 psi. But even with this valve system, I's still have a pressure relief in case you accidentally closed the valve completely.

We got back the first test results from the beta test today. The test showed a major reduction in the mixing time required to meet 3/27. This is the first verification of my own testing. I have not done any testing on the minimum methanol required with the eductor, yet. I feel those tests will show a marked reduction in the amount of methanol needed to make high quality fuel.

Great results, glad to have been onboard at the beginning.

Couldn't have gotten this far without your help! I still marvel at those miniture eductors you made.

The concept is working out well and I do think this is a great way to keep the power draw minimal and still have good large tank mixing. The only real concern now is materials. I'm still not 100% positive that these plastic eductors are going to hold up long term.

Jamesrl,

It will likely be some time before we will be offering eductors. I do like your work.



If you don't mind, I'd like to suggest an eductor for you that I think would do very well in the American Appleseeds.

Make the mini eductor just like you did above, only with a .25" to .3" ID nozzle in it. On the attachment, size the tube so that we can solder one of our 1/2" copper pipes into the end. That way the user can cut the copper pipe to fit exactly so the eductor nozzle is just below the oil before adding methoxide. He will need to add a 1/2" male npt adapter to the end. Then he can screw that into the end of a steel schedule 80 3/4" pipe nipple and mount everything in through the 3/4" port.

How is the testing going?

Any other reports good or bad?

Rick , is the primary use of the eductors for the HF and NT pumps , as they are of moderate performance ? What of your Italian pumps ? I assume using an eductor will help with the performance of any pump .

Scott, So far it's just the one tester reporting in. I expect a few more to report in next month.

dboib,

The primary use of the eductors is to get mixing in the tank. The HF, NT and my pump are all roughly about the same flow rates. Roughly about 7gpm. Mine has better quality castings and will usually flow a little more than the others. If we mix in the tank, we can get away with these smaller pumps. Without mixing in the tank we need larger pumps to turn the oil over before the WVO/Methanol emulsion breaks down, or before the glycerin starts grabbing methanol and lye away from the reaction.

The practical aspect of mixing in the tank is less methanol needed. We can compensate for poor mixing by adding more methanol (up to a point) Appleseeds generally need 22% to get high conversion fuel. The eductor can knock this down to 18% or lower that we see when using big pumps.

Another practical application is that with the eductor, we can dump all our methanol in at one time and speed up things a bit and not worry so much about adding the methanol slowly.

Yes eductors will work on any pump to increase mixing in the tank, but the eductor needs to be sized to the pump. The eductors were using in the beta test were sized spcifically for the NT/HF/B100 pump.

I'm thinking the B100 pumps will be able to take the pressure (about 25-30psi) longer without leaking than the other two.

The eductor were testing has a diffuser on it that increases mixing. The diffuser is not absolutely needed. Most of the pumps we are using are operating at the no-load end of their capability. All flow and no pressure so to speak. The eductor increases the pressure up into it's normal operating range while decreasing flow a little. We're tuning the pump and the whole system to operate more efficiently.

I think these devices help increase the mixing rate of the reaction.

By shooting a high pressure stream through an orifice, it draws in surrounding fluid all around and substantially increases the mixing rate of the fluid.

By definition, a restriction on the pump would decrease its performane, but with increased mixing, it would decrease the runtime, wear and tear of the pump, speed up the reaction, and save on electrical runtime costs of the pump (although minimal)

If it will help the Apple Turnover GL unit I will be constructing soon....I'm in!

We were typing at the same time....I see who is slower!

I think it would improve performance on a GL1day. But... You will need to split the output of the pump and either use the venturi or the eductor, but not both at the same time. The loading by the eductor would have a negative effect on the perfomance of the venturi.