Check out This site for some sweet chemical injection quills and also some turbine pumps Here that make my mouth water and my bank account shudder!!
Jon

here's an idea for the condensor.....i use fan in front of condensor instead of water circulating..and it works great...so i only needed to grimp my lenght of copper and stick fan in front...
water comes out ot meth at a nice rate

OK


Had my first go at the full GL Push Pull ... not totally successful.

I managed to get the acid to slowly drip in to the mix ... measured amount and expecting something to happen around the 100ml mark (110 ltrs in the reactor) waiting waiting by the time 120 ml's had gone in I thought I had missed the colour change and stoped the process. A tad early I suspect

Anyway ended up with a batch of slightly red bio ... my question is

If the mix goes too far ie too much acid what happens and how is it fixed ??


Will be giving another batch a go next weekend so keen to get some feedback.

Also how hard and fast is the 100 ltrs 100 ml ratio ... what are others experience of this??


Stuart

Hey guys. Thanks for such a great forum to share and teach about biodiesel.

I am building my 1st reactor, and have a stupid question.

In the Push-Pull you need to be able to reverse the flow to aid in the methanol recovery and keep the pure glycerin out of the pump.

Could you(and what disadvantages are there) always have the pump pumping into the bottom of the reactor upwards and keep the suction below the surface even during the reaction phase.

It seems the upflow sure would aid in the mixing during the reaction phase of the process.

Has anyone ever tried this?

Any ideas, suggestions, flames?

Tripp

Hello All,

I have been silently researching in preparation for building a GL Push-Pull Processor. Now I have to come to the knowledgeable masses with my first (of many) questions. I am buying a stainless steel tank for the processor and have narrowed my options to two tanks. The first is a 260 gallon tank with a dished top and bottom. The size and the price seem about right. It, however, is only rated for atmospheric pressure. The picture is attached. To make matters more complicated, there isn't anywhere on the tank to get a gauge measurement. Is there anyway to tell if it will stand up to the vacuum of the process? The second option is 200 gallons, almost three times as expensive, but rated for 100 psi at 350F. That, clearly, is overkill for my needs. So, can I safely take the gamble with tank 1? I have attached pictures of both tanks.

I have talked to handcuff about this already. He has been a huge help. We thought it might be a question worth asking everyone.

Thanks for the help.

atmospheric.jpg (34 Kb, 71 downloads)

quote:

Could you(and what disadvantages are there) always have the pump pumping into the bottom of the reactor upwards and keep the suction below the surface even during the reaction phase.

In my opinion, that probably wouldn't work. If you make a Dr Pepper, you'll notice the methoxide stays on top of the oil until you shake it. Methanol has a lower density than oil, and lye doesn't seem to change that, so if you mixed in reverse, you'd take the risk of ending up with partially (or totally, depending on the case) unreacted methoxide on top.

quote:

Is there anyway to tell if it will stand up to the vacuum of the process? The second option is 200 gallons, almost three times as expensive, but rated for 100 psi at 350F. That, clearly, is overkill for my needs.

There are ways to determine the thickness of the walls without needing access, but they're normally expensive, and kinda out of reach for the regular Joe, unless you happen to know somebody who has access to that kind of equipment. Either way, if it's not rated I wouldn't touch it.
about the 100 psi tank, I wouldn't be so sure it's overkill. If you read the first few pages of this thread, I made a similar comment about a compressor tank (IIRC, rated for 200 psi), and it was brought to my attention that pressure outwards is not always the same as pressure inwards. Of course, it all depends on how much vacuum you expect to draw on the tank, how full the tank is going to be, etc, but in any case, I'd be careful if drawing a hard vacuum to a 100 psi tank, especially one that big.

Hi kkelley30,
Its the negative pressure that is of concern as there will be no positive pressure in GL's design. It looks quite substantial but it's hard to say with a pic. What gauge is the tanks steel?
The only way to know, (as far as I know) would be to put it under vacuum...
For what it's worth my cheap hot water tank can take all the vacuum I can put it under and the tube is very thin maybe 18 or 20 gauge while the domed top and bottom are about 3/16" mild steel...

Best of luck!

Jon

Hi kkelley,
Looking at the tank in the picture my guess would be it is 12 guage or thicker. For the vacuum we pull in this process, my first attempt was with a 16 guage tank and it barely stood the vacuum, so I went to 12 guage and it worked great. I now use 240 gallon air tanks and they are rated 200 lbs.

If you can get a measure on the thickness, and it is 12 ga or thicker, I would not be concerned about using it.

Hello, I am testing out my system with water, and have discovered a few issues that I need some help on. The one for now is adding methanol.

The backstory:
This will start off sounding dumb but bare with me, I am film editor from a big city with power tools, not an experienced engineer (although perhaps a little more experienced now.) The original design called for the pump to inject the methanol into the oil. My first 'dumb' assumption was that if carboys were on the floor (below the pump) the pump would somehow magically suck the methanol out of the top of the carboys. Just so you know, before I actually tried this, it did dawn on me that pumps do not really 'suck' but actually do what their name says: pump, and so I altered my design. Looking at the appleseed system, I built a little table that is a bit higher than the top of my pump and put the carboys on top of that and ran a methanol transfer hose from the carboys down to a ball valve below the pump – V2 in my pictures. Problem solved right? Yes actually, but now I have another issue, something I think is called "Vapor Lock"

The issue appears to be that air trapped in the methanol transfer hose is getting into the pump and thus the pump stops circulating liquid. This issue occurs at the beginning of my process when I first open the ball valve and again at the end as carboys are nearly empty and the methanol (water) becomes a trickle. I can get the system back to circulating if, with the pump running, I open the valve to the outlet for the whole system (V1 Out) and bleed a little liquid. I am not crazy about this workaround as now I have to deal with concentrated methanol or oil being pumped out of the system.

Any suggestions?

Here is a picture of the pump set-up and a link to a whole bunch of pictures (although slightly old now). Doug's Push Pull Pics One other question about my setup and this issue of vapor lock. See V2 on the lower right? This is where the methanol is being injected. If I moved this port to the left of the pump or put a 4-way-T just under the pump, would this solve my issue? Or should I just bite the bullet and add a venturi to the system and inject methanol that way surely making dealing with methanol a whole lot safer.

Thanks
Doug

pump1.jpg (33 Kb, 42 downloads) Doug's Pump set up.

Doug: you might be able to try the technique I use: if my processor is running, and I open the valve that connects the methoxide tank to the pump intake (your V2) while the processor tank intake valve (your V8) is also open, then the oil will flow backwards through the methoxide line into the methoxide tank. I let it do that, to push the air bubbles out. After a few seconds of this reverse flow I can close the processor tank valve (your V8) and suck in all the methoxide in one go, without vaporlock. Note that most people prefer to suck it in slowly, but I've found no advantage, with my processor.
Cheers,
JohnO

Hi Doug,
On my push/pull I use the vacuum at about 5Hg to suck in the methoxide through the same port I add the oil in(pump running). It works excellent! I also draw a vacuum to pull the WVO in, much faster than pumping...
I finally got some phenolphthalein this week so I will also use the vacuum to draw in the acid through the same port. The vacuum is the best way to draw anything into the processor IMO.
Jon

Thanks John and johno.

John, I am little unclear about your set up. Do you use a venturi to create a vacuum? You also add oil through this but if there is no oil in the venturi, then there is no vacuum... I am clearly missing something important in your answer. Could clarify it for me? Have a picture perhaps?

quote:

it is 12 ga or thicker, I would not be concerned about using it.

Be aware that the larger the tank the thicker the walls generally need to be to withstand atmospheric pressure from holding a vacuum. I know this is a comparison of like with like size wise but any readers considering larger tanks should bear this in mind. Also the shape of the tank makes some difference. square tank not so good. Any unbraced flat sides not so good. cylinders with domed ends better. Balls and eggs the best.

Doug,
I use a conventional rotary vane vacuum pump instead of the venturi vacuum tank setup GL designed. If you have a push/pull setup based on GL's design then you should have the separate tank with venturi to create the vacuum?
Just apply vacuum and feed the meth or oil in through your V2-in with your mixing pump running.
I highly recommend a needle valve on the suction line of the vacuum to regulate the vacuum by letting air in, keep the needle valve close to the venturi or pump.
I need to get some pictures of my setup but just haven't found the time lately... maybe this weekend.
Here is a pic of my vacuum regulator from awhile ago HERE
Jon

Thanks Jon,

Pictures would really help because I think you have made some interesting modifications that I can not envision. I know in the GL Push/Pull where the Vacuum pump is located, but where is your vacuum pump located? How do I

quote:

Just apply vacuum and feed the meth or oil in through your V2-in with your mixing pump running.

I must admit, liquid/gas dynamics is not my strong suit. Since you have successfully altered the GL Push/Pull system, I would love to hear how did it and explain the the flow step by step, especially if you can't take pics.

Thanks
Doug

Doug,
I should point out that GL is not in favor of using a conventional vac pump as I have.
My setup is much like GL's except for I am using an apple turnover with piping into the mixing pump from 2 locations the bottom and the side element port (above the glycerin layer ) and the pump output has 2 inlets to the tank one at the top via the old tank drain and one through the old lower element hole with a home made eductor, all controlled via valves. My vac is not between the condenser and reactor but rather after the condenser. I used a large glass wine carboy for my collection vessel and the vac is after that.
All that said for your setup just run your venturi/rapeseed pump to put the reactor under a slight vacuum (5 to 10Hg) when your ready to add the meth. Then slowly open V2 and the vacuum will steadily suck in the meth at whatever rate you want, controllable by V2. After the meth is in turn off your vacuum and that will relieve the vacuum pressure for processing.
Does that make more sense?
Jon

Thank you all for the advice. There really wasn't anyway to get a measure of the gauge on that tank, so I don't think I'm going to risk it. I'm now looking into lpg tanks and the 240 gallon air tanks that alken mentioned. Not using stainless makes me nervous, but maybe the saving is worth it?

Thanks Jon.

Ok here is a another silly niave question about something I am experiencing but can not figure out why or what to do with it.

My sight tube is only useful when there is pump is NOT in use. Otherwise my pump sucks everything out of the sight tube, and then also introduces air into the system. I even have the sight tube hooked back into the system at its top Is this correct or did I do something off?

Doug

A second question:

Graham,

In the Push/Pull version, what temps are people heating the oil to for dewatering and the later for demethying in the push pull version? In the GL1, Graham indicates going to 90c at both those stages, but here he mentions doing it at lower temps, but I can't find a recommend temperature.
I see to wait to the oil is 55c to add the methanol but what temp is the oil before?

Thanks
Doug

Doug,
As I understand it. 55c/130f is the reaction temp. The temp that you will demeth/dewater depends on how much vacuum you are able to create, the higher the vac, the lower the boiling temp. I believe Graham recommends a start point at around 70c. never to exceed 90c. The lower the vac the more you will be able to drop below 90c.
Dave