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DONT put your methanol carboy above your Appleseed!

This topic can be found at:
http://biodiesel.infopop.cc/eve/forums/a/tpc/f/919605551/m/4021020801

September 27, 2005, 04:54 PM
girl mark
DONT put your methanol carboy above your Appleseed!
There's a discussion going on at the biodieselbasics list, about the fact that many people tend to mount their methoxide shelf up high, above their Appleseed processor. I think they're learning it from other pictures on the Web- it's not in the original designs.

This practice usually puts the can of methanol at 6' height or so- eye level or above.

This is a safety concern for several reasons-

a. you're lifting something heavy above your waist- ladders + methanol = dumb

b. the 'something heavy' is methoxide which could leak into your face or eyes (out of the vent if you jostle it with the vent open while lifting, for instance)

c. it's completely unnecessary - you dont get any more assistance from the extra height than you do if you place the carboy at waist level or even on the floor.

At http://www.biodieselcommunity.org/appleseedprocessor you'll see that my carboy is just above the pump, but apparently some people have just placed it on it's side on the floor and gotten good results (I haven't tried this myself).

At http://www.biodieselcommunity.org/appleorchard you can see how prevalent this 'carboy above the processor' practice is. We're discussing what to do about the Apple Orchard photos- a disclaimer, or asking the original photo authors to re-take a photo without the high carboy placement. Earlier this spring I had already corrected the Biodiesel Homebrew Guide design to make this lower placement more clear.

DON"T DO IT THIS WAY....

Mark

This message has been edited. Last edited by: Shaun,
September 27, 2005, 05:04 PM
DonTSA
.... crap i designed my stand around that.... looks like ill have to modify it...

ill redesign it in CAD and run it by the forum... see how that design runs or ill just chop it and move the shelf ill take pics of course
September 27, 2005, 06:20 PM
girl mark
the first time you run it, see if it still works with the carboy on the ground or on a chair or somethign (mine usually ends up on the closest barrel, much less elegant than a built-in stand...)

Mark
September 27, 2005, 06:33 PM
ReM
quote:
Originally posted by girl mark:
the first time you run it, see if it still works with the carboy on the ground or on a chair or somethign (mine usually ends up on the closest barrel, much less elegant than a built-in stand...)

Mark


I have made about 2000 gal in the last 18 months with the carboy located lower than the Harbor Freight pump by about two feet.

Works just fine using using the low pressure on the inlet side of the pump to suck the mixture in. Flow rate is adjusted by the two relevant valves--- actually the valve from the carboy side is left wide open and the mixture flow rate is controlled by the valve between the bottom of the water heater and the pump.

ReM


B100--
2004 Motorhome CatC7
1987 Mercedes 190D 2.5 Turbo(possibly for sale)
1983 VW Pick-up (Caddy) 1.6 Turbo
Southern Oregon
September 27, 2005, 10:21 PM
OB1 CANOLA
Thanks Girl Mark
good find .
I put my shelf high also .Just thought it was supposed to be like that because of all the pics iv'e seen here..This is what we call in the
mfg industry as "Continuous Improvement"
I thought that it was gravity fed more or less. Never considered it was sucked in by the pump. I will shorten my hose and lower the shelf.
I guess I still want it higher than the check valve .. My processor was built high enough off the floor so i can get a 5 gallon bucket under it
October 02, 2005, 04:26 AM
Graydon Blair
I did some experiments today with water using the carboy at different heights.

This is the unit I tested it on today
http://www.utahbiodieselsupply.com/photos/processors/50gallon02/


(Yes, that is a shelf wayyyyy up there in the stratosphere---it's the last one I'll make like that, I promise).

Anyway, back to the experiments.
If you look closely at the pics, you can see I've got a 1/2" Check Valve just below where the methoxide comes into my plumbing.



I stuck the carboy below the pump, opened the valve wide open w/ the pump on & nothing. It just sat there.

I raised the carboy up to about belly-button level & still nothing. So then I restricted the flow of the pipe coming from the drain on the tank, whoala! the flow on methoxide started.

But, because I had restricted the flow of oil (it was water for the test today), the methoxide was now gushing in at a rate faster than it should.

So, I've gotta figure out a way to be able to stick the carboy low (just above the pump), still get that check valve to open (it's not a spring check valve, just a swing one) and also not dump the methoxide into the tank too fast, which could cause a poor reaction.

I think w/ my present plumbing the carboy's gonna have to be higher than the pump by about a foot or two at least to get the flow moving because the Harbor Freight pumps will only pull so much suction.

Any recommendations? What am I missing?
-Graydon
One of the designers of carboy's above eye level (Bad Graydon, Bad, Bad Graydon)
Willing to make improvements....

This message has been edited. Last edited by: Graydon Blair,




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October 02, 2005, 04:43 AM
Ant
Without disagreeing with the basic principle of doing things safely. I have to dissagree that you get no assistance from the extra hight. I believe you do and I believe that Graydons experiments bear that out. More hight more head/potential eneregy equals more assistance to the venturi effect of the pump sucking it in.

Imagine a U shaped tube with your processor on one end and your methoxide on the other. Ignore the pump for now. if both ends are at the same hight the liquid will be at the same level in both of them and not want to move. If one end is raised then the liquid will want to remain at the same absolute level and so leave the raised tank. So there is something to be said for having your methoxid above the top of your processers fill line.

I use a stainless methoxide tank above my processor. I pump my methoxide into it from the ground using an air powered pump. It is quick easy and safe.

Even then, when experimenting with unusually high reaction temps I had a problem with the meth not all coming out. I added the ability to put a little air pressure in the meth tank and this displaces every last drop quite handily.

Of course this pressure can replace the height entirely.

I think it is how you do things rather than a blanket "dont do this"


mathematical elegance -- desired result achieved with minimal complication
October 02, 2005, 10:03 AM
Legal Eagle
Actually this is a reminder, thanks. I am redesigning my reactor set up in a new "home" and was thinking of lowering the methoxide feed, for it is not necessasry for it to be "up high" as stated.
I always test the security of the caps before doing any lifting though, as should be the practice when dealing with anything potentially harmful.
The new set up will have it on a short stand just above the pump so that minimal gravity is acheived. This, with the aid of the air pressure from the aquarium air pump through the vent cap should be plenty to get it introduced into the oil flow and past the check valve.

I am also playing with the idea of a second reactor in-line so I could place the methoxide feed between them, nice and snug.The new reactor paqe will also be changed as soon as it is available, but still at the same URL.
Mark, you are welcomed to add my name to any disclaimer dealing with this, along with any comments you may feel usable.



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October 02, 2005, 10:58 AM
girl mark
Graydon,

I always have to close off the oil control valve slightly to get the methanol to start flowing and height didn't help change that. The majority of users I know seem to need to close off the oil control valve to get flow going...

Because that's different than what you're seeing, I'm guessing that the amount of 'back pressure' from the processor tank probably varies by size and shape and by how quickly the excess 'pressure' (the make-up air that's being displaced by the added liquid, and any methanol vapor that's evaporating off) can exit the tank (so if you have a tiny vent tube it'll exit slower than a large one, perhaps??). My tank on my processor is twice as large as people normally use so that may be the difference between your experience and mine.

Ant, if you're experimenting with extra high temperatures, you're dealing with something quite different than we are (you're boiling off methanol which will DEFINITELY cause extra high pressures in the reaction tank which will inhibit a centrifugal pump from sucking in methanol from a tank at lower pressures. Instead of adding compressed air to your methanol tank, you could just connect the two tanks so that the pressures equalize. That's difficult to do with a carboy safely (ie what if the tube comes off the barb and you're now venting methanol into your workspace?) but easy to do with any other kind of tank where you can securely attach fittings. My friend Lu was calling that a 'eustacian tube' after the things in your ears. It gets us past the 'close off the oil control valve slightly' problem but doesnt' work with carboys safely in my opinion.

Mark
October 02, 2005, 11:24 AM
ReM
"Any recommendations? What am I missing?"

I have foound it very easy to modulate the "methoxide" flow by varying the setting of the valve in the tank bottom--

As stated in my previous post my carboy is about a half meter below the pump and check valve.


I know we are all "tinkerers" but it sure seems like many of us tend to make things much more complicated than they need to be. Smile

ReM


B100--
2004 Motorhome CatC7
1987 Mercedes 190D 2.5 Turbo(possibly for sale)
1983 VW Pick-up (Caddy) 1.6 Turbo
Southern Oregon
October 02, 2005, 11:53 AM
DonTSA
tell me about it Big Grin
October 02, 2005, 06:12 PM
Legal Eagle
Graydon and Mark;

PLug an aquarium air pump to the vent cap opening, the presurizing of the carboy will flip the check valve open. It HAS to, laws of physics and all, or is that thermodynamics? Anyway, the high pressure area flows into the lower pressure area.
My plan is to set the methoxide feed on a short pedestal between two reactors for my next trick...



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October 02, 2005, 10:43 PM
Graydon Blair
Ahh.....cool.
That answer's a few questions.
1- Restricting the flow of oil (the drain valve) is common
2- Once the flow get's going, opening the oil valve wide open again & restricting the methanol flow ensures that the methanol will be introduced at the right feed rate (not too fast).
3- I'll have to try the "pressurizing the carboy w/ an aquarium pump" idea.

Any pictures any of you have of your setups w/ the carboy's lower than "above the fill line" would be great.

Thanks again for the great feedback (I LOVE this forum for that reason--I keep stuff like this here & off of the basic's forum on purpose).

If you have pics & can't host them, email them to me & I'll host them for you.
-Graydon
graydon@utahbiodieselsupply.com

Thanks again!
October 02, 2005, 11:44 PM
ReM
[QUOTE]Originally posted by Graydon Blair:
Ahh.....cool.
That answer's a few questions.
1- Restricting the flow of oil (the drain valve) is common


2- Once the flow get's going, opening the oil valve wide open again & restricting the methanol flow ensures that the methanol will be introduced at the right feed rate (not too fast)."

There is no need to do this-- just leave the methanol valve open and modulate the flow with the oil valve.

"3- I'll have to try the "pressurizing the carboy w/ an aquarium pump" idea."

This will work but why make a simple process more complicated ?

ReM


B100--
2004 Motorhome CatC7
1987 Mercedes 190D 2.5 Turbo(possibly for sale)
1983 VW Pick-up (Caddy) 1.6 Turbo
Southern Oregon
October 03, 2005, 12:15 AM
girl mark
quote:
Originally posted by ReM:


"3- I'll have to try the "pressurizing the carboy w/ an aquarium pump" idea."

This will work but why make a simple process more complicated ?

ReM



Thats also my response to this practice- I think a couple of other people agree with me that it's a bit unsafe sounding. I dont' like the idea of pressurising a plastic can of methanol, no matter how little pressure you're using.

Mark
October 03, 2005, 01:02 AM
Graydon Blair
There's a problem with the following:

2- Once the flow get's going, opening the oil valve wide open again & restricting the methanol flow ensures that the methanol will be introduced at the right feed rate (not too fast)."

There is no need to do this-- just leave the methanol valve open and modulate the flow with the oil valve.
=========
If you leave the methanol valve wide open you'll be inducing way too much methoxide way too fast, even if you're restricting the oil flow. It's the methoxide you need to restrict, not the oil.

If you put the methoxide in too quickly I've had problems with it not completely reacting right. Slow the flow of the methoxide down against a steady stream of oil & it works out all right.

Sounds good on not pressurizing the carboy.
Soooo......if you don't pressurize and you're sticking it only a few feet above the pump, how do you adequately:

[A]- Get the flow flowing past the check valve w/o gravity's help and
[B]- Not add too much methoxide at a time to the oil thereby possibly causing an incomplete reaction?

-Graydon




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October 03, 2005, 11:53 AM
ReM
quote:
Originally posted by Graydon Blair:
There's a problem with the following:

2- Once the flow get's going, opening the oil valve wide open again & restricting the methanol flow ensures that the methanol will be introduced at the right feed rate (not too fast)."

There is no need to do this-- just leave the methanol valve open and modulate the flow with the oil valve.
=========
If you leave the methanol valve wide open you'll be inducing way too much methoxide way too fast, even if you're restricting the oil flow. It's the methoxide you need to restrict, not the oil.

If you put the methoxide in too quickly I've had problems with it not completely reacting right. Slow the flow of the methoxide down against a steady stream of oil & it works out all right.

Sounds good on not pressurizing the carboy.
Soooo......if you don't pressurize and you're sticking it only a few feet above the pump, how do you adequately:

[A]- Get the flow flowing past the check valve w/o gravity's help and
[B]- Not add too much methoxide at a time to the oil thereby possibly causing an incomplete reaction?

-Graydon




Graydon--

This is really very simple-- by varying the setting of the valve that is feeding the oil you are also varying the pressure (actually you will produce a partial vacuum) at the input junction of the "methoxide" feed. If you restrict the oil feed the pump will draw from the "methoxide" side. By adjusting amount of partial vacuum you have nearly infinite control over the velocity at which the "methoxide" is drawn into the pump where it is mixed by the impeller with the oil.

In practice you open the "methoxide" valve fully and then close the oil feed valve until the "methoxide" check valve opens and the mixture begins to flow. You will then need to gradually open the oil feed valve until you have established the "methoxide" flow rate that you desire. You may need to further reduce the oil feed a bit as your "methoxide" container nears empty in order to maintain the desired rate.

It is desirable for your "methoxide" plumbing to be of substantially smaller diameter than you oil plumbing-- makes thing easier to control.

Most use 3/4" plumbing for oil-- 1/2" or smaller check valve and tubing for "methoxide".


It is simple
It works
it WILL draw from the container even from substantially below the pump level.

(upon reflection-- if your "methoxide" container is higher than the pump you may possibly have a bit less controll due to siphoning-- since I have never tried this with the container up high I am not sure what the effect would be)

ReM


B100--
2004 Motorhome CatC7
1987 Mercedes 190D 2.5 Turbo(possibly for sale)
1983 VW Pick-up (Caddy) 1.6 Turbo
Southern Oregon
October 07, 2005, 06:26 AM
Ant
Well I don't experiment with high temps anymore. I agree pressurising plastic is a possible danger, I use stainless, a beer keg would work well.

The main point I was illustrating is that there is an assistance to be gained from hight. I was simply trying to keep a clear understanding of physics on the board.

Whether this assistance is needed is another debate.

Air pressure is a very simple method with no moving parts that does not need the same custom tinkering with oil flow to balance for individualy sized and shaped processors, piping and pumps.

I always circulate my oil at full speed to turn over the contents as fast as possible and get the best mixing. I can use the valves on the methoxide to adjust the mix and will always get positive flow into the mixing tank thanks to a little air pressure.

This may seem overly complex to some but I find it easy and relaiable in practice. It was the Diff who first suggested it to me and at first I thought it would be difficult to implement. But in describing the problem I found I had described the answer and it was fairly easy to do and once done very easy to use.

The pressures involved are only a pound or two above one bar. Not terribly dangerous really. If you do things right. Which was my original comment. It depends how you do things. Different methods can be safe if done well.


mathematical elegance -- desired result achieved with minimal complication
October 08, 2005, 12:11 AM
Legal Eagle
You get a whole whack more "pressure" from the reaction just mixing up the methoxide than you do with an aquarium air pump that can be controled with an on/off switch. I'll let you know if I blow anything up K?



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- on 5 continents helping people make & sell soap from the Biodiesel Glycerine.


October 08, 2005, 05:22 AM
Ant
That is a good point. I have had barrels blow up like balloons from meth mixing; bulging outwards on all sides without any ill effect or bursting. It is obviously very silly of me to allow that to happen but it has been safe so far. HDPE is pretty resiliant stuff. I think joints and seams are your weaks spots.

Let us know how it goes.


mathematical elegance -- desired result achieved with minimal complication