There have been a lot of people trying different things to improve mixing in the Appleseed. Some have gone with larger pumps, and split either the input, the output or both. Some have gone with two pumps. Some have strived to get a vortex in the tank others have put an eductor in the tank. And I almost forgot the static mixer and simply going with larger plumbing. If I left someone out, please speak up.

After long conversations with several Chemical Engineers I found another method, The High Velocity Nozzle. You can see how it works by adjusting the garden hose sprayer so it sprays a long straight stream and then stick it in a bucket of water. If it’s below the surface it will roll the water in the tank. The high velocity stream grabs the surrounding water and drags it along just like it does in an eductor. If the hose is off center you can really get it rolling.

This week I’ve been conducting some experiments on mixing, including the high velocity nozzle. The nozzle I’m currently using is a 3/8” steel hose barb with ½” male pipe threads. I’ve extended the return pipe to below the surface of the oil and added the nozzle. I’ve tried it with two different pumps in a number of different configurations. I’ve seen a couple of trends. One is obvious, the warmer the oil the lower the viscosity and the higher the flow rate. The other is that warmer oil needs a smaller nozzle.

The nozzle I’m using has a ¼” hole through it. At 80F it has a 10% reduction in flow. At 94F it no longer has any noticeable reduction in flow.

The nozzle seems to be the least expensive way to improve mixing in an Appleseed. And it’s not to difficult to install without special skills. I’ll keep you posted as I continue the experiments.

Rick
I'm about to replace my 50gal (upside down) Appleseed with a 80gal. 4 ¾" ports in the top (now the bottom). Tank is 58" tall. Cut 54" of threads on a 66" length of ¾" pipe inserted in tank and attached to output of pump. Input to pump is from another port drawing from the bottom. This pump and plumbing is in addition to the other pump used in the system.

"The 80 gal. Double Pumper Turnover"

This is how we rigged our 80 Gal. apple turnover.
Note the center pipe for the drain, right and left pipes for pump inlets, then 1" out to the old heating element port, using a baffle in the 1" Tee to merge the flow, then into the top via the nozzle shown below to create a swirl in the tank.

1" outlets manifold together into 1" element port.

Note: 220V into the box, each 110 leg feeds one pump.
Only when both pumps are on will the 220 supply the heating element.

Left pump takes in WVO, right pump takes in methoxide.


The nozzle is a 3/4" "L" cut down and attached to the 1" pipe where it enters the tank.


The 1" "Special-T" has a baffle added to merge the flow.

BobAbbey
Both pumps are pumping into that ¾" nozzle..?

Blackie,

Have you already got that pipe threaded? How much did it cost? Where did you get it?

Rick
I threaded it myself. Just looks like a piece of all-thread only it's pipe.

Blackie,

Yes, the one inch tee, to the one inch pipe with the 3/4" nozzle.

The size reduction will increase the exit velocity. Like Rick explained using a smaller nozzle.

I like what Rick is saying about entering the mix below the surface to "roll" the whole mixture. The important thing is to get the methanol off the top and back into the blend.

Bob

One thing I noticed on my test rig. Restrictions on the input side of the pump have a much more dramatic effect on flow rates than restrictions on the output side. I think pumpbuilder has pointed this out before, now I know it's for real.

My next modification will be one inch plumbing on the inlet of my pumps. Still stuck with the 3/4" tank threads, unless I weld in some 1" bushings.

Bob

I have an abbeynormal question...

Which way should we spin the vortex in the tank?

Clockwise would be natural in the northern hemisphere, but would it mix better if we contradicted the natural??

Bob

Bob,

Have you done tests which show improved reaction? Faster pass of 3/27, or lower methanol use and still complete/good conversion?

Andrew

Tilly's World Famous Patented Vortex Generator



Gee, it has taken you fellows a long time to realize this is the best way to mix biodiesel!

Rick,

Of course you have good ideas about how to set up tests...

quote:

The nozzle seems to be the least expensive way to improve mixing in an Appleseed. And it’s not to difficult to install without special skills. I’ll keep you posted as I continue the experiments.

I have suggestion though-

Can you run head to head tests with the improved mixer compared to the identically set up processor with out it? Take samples every 15 or 30 min. to be able to see if the mixing is aiding process time. Then run a batch with a marginal level of methanol, like 18 or 19% and see if the improved mixing one gets it more fully reacted after 4 hours or something like that.

What do you think?

quote:

If I left someone out, please speak up.

As you know, my processor combines several of the features you mention - static mixers, larger inputs & ouputs, plus one feature you did not mention directly - an input to the pump from the upper layer of the tank. I currently think this is good feature, but it might not be necessary with your high velolcity nozzle. More tests...

Andrew

I may try this instead of my failed effort to get the tank contents to swirl.. It shoots out too close to the wall of the barrel and runs down the side. I still get fuel that passes up to 15/27 tho.. (I stop testing at 15, it could probably go higher). How about shooting it down from the top, and letting it make a hard impact with the surface of the liquid inside?

I suggested quite a while ago that a sideways ejecting nozzle would be an aid to mixing in an Appleseed. And it was as simple as plugging a piece of pipe and drilling holes in the side. Number and size of the holes would determine velocity of the stream (as well as backpressure capability of the pump). I have never used an Appleseed, so I suggested this as something some one should try.

This is something I built to accomplish that type of swirling in a drum. Notice the holes drilled in the side of the shorter discharge pipe. The end of that pipe is plugged BTW. HTH

Hello Joe
I think your adaptor is a great idea. It reminds me of the periscope binoculars used by german army officers that you see in old WWII films.

Andrew,

I'm running these tests in drums in the front yard. The bioshed still does not have electricity. I pushed up the initial phase (in drums) of the mixing tests because of a new pump I found and am testing at the same time. It will probably be another few weeks before I can fire up the appleseeds.

300SD81,

It's better to be below the surface. When above the surface, the nozzle will aireate the biodiesel. It's not hard to get below the surface. If you replace the nipple that screws into the top of the appleseed with a schedule 80 nipple, you can tap full 1/2" threads inside the nipple. Two or three feet of half inch pipe does not and measurable resistance. I'm going to take some pictures tonight and show how to peice one together with copper tubing.

Joe_M,

I spoke with the engineers about your suggestion as I thought it was the best option, but they insisted the nozzle needs to point straight down. They said that if the velocity was high enough, it would create the vortex without needing to point it off center. The 1/4" nozzle is barely taxing the pump, so I'm going to try a smaller nozzle tonight or tommorow.

Hello Rick
Engineers?

Tilly,

Yes, Chemical Engineers with a combined 60 years experience. They provide a starting place for testing. Comprehensive, full scale testing takes a lot of time and some money, So I'd rather get an experts opinion in addition to the execllent forum experience before I start testing.

Let's not take this thread off topic please. It's about experiments in mixing and how to improve mixing in the Appleseed.

Hello Rick

Good to hear. It should have been done long ago.
I think A very easy way to test the vortex generating capacity of a stream of biodiesel shooting straight down into the reactor is to fill a drum with water and shoot a stream of water from the hose into the water in the drum.
If the information you have been given is true you should generate a vortex.
I think I will try it myself.