I am going to experiment with Supercritical methanol, I have searched but have only found references to people talking about doing it. This shall be an actual experiment.
Posting about my work is against by better judgment as I detest the lectures of "you'll shoot your eye out"... but I figured I'd give it a shot. If this thread becomes polluted with the anticipated safety warnings, I will not continue my work publicly.

But before I continue I will address the issue of safety.
To ensure my longevity I have incorporated the following precautions into my experiment...
1: The chamber in which the supercritical reaction will occur shall be inside of metal tubing rated for high pressure.
2: The tubing shall not contain enough fluid to create a fire larger than hand held gear can control.
3: The tubing will be submerged in heat exchange oil which will be housed in a container suitable to contain the fragments should it rupture.
4: The entire reaction vessel assembly will be at a safe distance.
5: I will monitor all gauges via CCT cameras.
6: Heat and pressure will be controlled from my location, away from all processing equipment.


Overview:
This is a strictly educational experiment, I do not intend to produce any significant quantity of fuel using this method. I simply hope to learn something new.
While the reported numbers I've found in my preliminary research vary wildly, I have decided that 500*F and 3,000psi with 5 minute residency time is a fair baseline to start with.

Equipment & Construction:
I have a standard air powered hydraulic pump with a 1/100 ratio... IE. 1psi air pressure = 100 psi hydraulic pressure. It is rated for 10,000psi. Using a 2hp air compressor with a 30 gallon tank, I plan to regulate the air pressure to the pump to control the fluid pressure. I have a 0-5,000 psi gauge to monitor the fluid pressure. A mixture of virgin vegetable oil and methanol will be fed into the reservoir which feeds the hydraulic system. An agitator may need to be installed into the reservoir to prevent separation. The exact oil/methanol ratio required is still an unknown but I will start with as much as stays in solution in test samples.

After the oil/methanol solution is pressurized in the pump, it will be sent down a steel hydraulic tube with a "small" inside diameter, to keep the volume of mixture low for safety reasons. This steel tube will be bent into a coil and submerged in heat exchange oil. The coil and heat exchange oil will be stored inside a metal container such as a small air compressor tank. A 110V hot water heater element will be used to provide the required heat. A 150-750*F thermometer will be installed in the tank. Temperature will be controlled via an on/off switch attached to the heating elements power cord.

After air is purged from the lines, the steel tubing will be capped and the coil submerged in heat exchange oil. The top of the vessel will then be attached with the thermometer installed in the top. After 500*f is reached, the pump will be turned on and regulated to 3,000psi with the pressure gauge reading between the pump and the metal tubing. After 5 minutes residency is achieved, heat and pressure will be turned off. After the pressure gauge reads zero, the coil will be removed and submerged in water until cool to the touch. Then the cap can be removed and contents analyzed for separation.

Assuming that all equipment lives up to its expectations, the experiment will be repeated with varying temperature and pressure. The ultimate temps and pressures will depend solely on equipment limitations.

I already have most of the equipment. Construction will begin tomorrow.

quote:

Originally posted by Donniej:
. . . . I simply hope to learn something new. . . .

I am sure you will!

Please keep us posted on your progress.

Ive read articles about researchers using this method in japan, but never any homebrew use. Kudos to you Donniej, excited to hear the results!

Do-it-yourself science at this level is cool. Since you are obviously aware of the risks and have taken appropriate measures, the nanny-state safety lecture is happily omitted.

Please carry on.

Please keep us posted.

Finest regards,

troy

Good luck.

I would suggest bumping your pressures up in 500 psi incremements from 500 psi until you reach 3000. I work with fluids under pressure up to 4000 psi, and failure rates go up exponentially as the pressure increases. If you step it up in stages, you are likely to find your weak points before they become critical. Good luck and let us know how it works out.

Hooknline,
Excellent suggestion. I'll be sure to do so.

Interesting thread. Good luck and please post some pictures!

UPDATE:
While talking to my Dad (an industrial machinery guru), we decided that exposing my pump directly to methanol was a bad idea. The seals are not rated for it and while it would probably work from the purpose of my experiment, I'd rather not throw away the pump afterwards.

Instead I bought an air powered hydraulic bottle jack rated for 20 tons and a standard automotive bottle jack rated for 12 tons. The 12 ton jack will be gutted and used only to pressurize the oil/methanol mixture.

Here's how the new contraption will work....

The 20 ton jack will act as the master cylinder. From my remote location, I will feed it compressed air to compress the "slave cylinder" (the 12 ton jack). The slave cylinder will not be heated, we'll get into heat in the next paragraph. The master/slave cylinder configuration will go as follows. A structure will be built to house both jacks. The jacks will stand vertically with the slave upside-down. The pistons will meet face-to-face with some sort of small metal pad between them. The slave will be upside-down to help bleed out air through its only fitting, which will be on the top in this orientation. A pressure gauge will be installed in this same fitting via a "T". The structure assembly holding the jacks together will have to be sturdy to withstand the minimum 1 ton pressure trying to push it apart. It will be constructed out of 2 layers of 1/4" mild steel plate top and bottom (ie 1/2" tick top and bottom). They will be joined via 8 pieces of steel water pipe, 2 per side. 3 sides of which will be welded, one side will not be welded so the pipes can be removed to install the jacks. All 8 pipes will be also attached to the upper and lower ends with threaded rod, nuts and washers extending through the entire assembly.

This will provide a reliable high pressure mixture of oil and methanol. Simply mix them up and pour them into the slave cylinder and bleed out the air. After which it can be fed into the tubing submerged in a heated oil bath I originally described.

The other advantage of this design is the slave jack is cheap. If I destroy one or two, it's no big deal. The master jack is more pricey so I'd like to keep it in good shape for reuse in future experiments, or working on my truck.

I plan to break out the MIG welder and ban saw this weekend. Hopefully I can find some 1/4" plate...

Will this produce enough pressure for your experiment?

A quick google search for "8 ton bottle jack" yielded a picture that shows a typical jack. The inside diameter of the base will dictate your available working pressure.

The diameter of the jack was not listed but it looked to be somewhere between 3" to 5" inside diameter.

The fluid pressure produced at the outlet fitting (assuming the small activating cylinder is removed) is between 800 psig and 2200 psig if the inside cylinder diameter is 5" or 3" diameter, respectively.

Theses values are based on an 8 ton force on the piston. You may be able to go up to 20 tons, but I would worry about the seals on the 8 ton unit if pressured beyond 8 tons.

Good luck.

I wonder how many people discovered Nitroglycerin
before Ascanio Sobrero discovered it??
HA HA! I love Shade Tree Science!

Producer,
I have no idea what the internal pressure will be. The slave is a 12 ton jack. It was cheap so if I blow it, I'm not going to stress too much.

Even if it can't handle the pressure, it should be able to handle it a few times...

Donniej,

Whew...

I read quickly through your posts and it sounds like you are using standard hydraulic cylinders/jacks.

I would suggest a double-piloted check valve for the cylinders. Here is a link for its use on a 3 pt hitch on a tractor. http://www.ccmachinery.com/public_html/images/FAQ_toplink.pdf

This one is only good up to 600psi.

Essentially, it locks a cylinder if one side fails.

With the temps (500F?) you are talking, you could very easily have explosive decompression. That will happen if your temp is enough to ignite, but it is being held in liquid form due to the pressure. When the pressure release (or fails), the temp is left and the fuel ignites.

The second possibility that comes to mind is at what pressure/temp does the chemical ignite? You are probably familiar with the term "dieseling" referring to diesel engines.

Many of the heavy equipment diesels I've run (and lighter, too) have a fuel shutoff, else it's nearly impossible to shutdown a diesel that has started dieseling due to temp, pressure, or some other failure.

Of course, I'd never recommend you try any experiments, but if it were me, I'd rig a way to remotely control the cylinders and try compressing it to my target pressure *without* heat. You may find a point where it ignites or becomes unstable.

Just be aware of blast area and shrapnel. A hot water heater that explodes can be shot through a roof. That's why they have relief valves now (google some info about early hot water heaters without relief valves if you want something interesting).

I don't recall the psi ratings back then, but today's are usually rated around 150psi.

FYI. Backhoe cylinders I use are often around 2500-3000 psi. 6k is nothing to sneeze at!

Good luck and be careful.

- JC

Hello JCBiodiesel

Remember, there is a "No talking about safety" caveat to this thread.
I hope you were not talking about safety concerns!

Just sit back and enjoy.

this 20 ton jack. If it has a 2" dia ram the the ram has a surface area of 3.142 sqr".

As 20 ton is 2240 * 20 = 44800 pound then this would give (I think) 44,800/3.142 = 14,258.4 Lb/sqr inch available at the ram.
If I am right with this calculation, surely this is more than enough pressure ?

regards
dva

quote:

Originally posted by Tilly:
Hello JCBiodiesel

Remember, there is a "No talking about safety" caveat to this thread.
I hope you were not talking about safety concerns!

I wouldn't dream of it!

Yeah, I read that part. I thought my post was more to suggest a helpful piece of equipment and an optional procedure to get up to the pressure he wants to use.

I mentioned the safety part because it justifies the reason for the suggestion, and...well...just couldn't help myself!

I really appreciate experimenters and fellow tinkerers. I spent a number of years in R&D. Even though one may be "safe" from an injury point, it still really stinks to lose your gear because you didn't foresee a particular outcome

I hope he is successful and look forward to this and his future experiments.

Oh, yeah, and just because I had a good reason doesn't mean I'd ever try to rationalize my otherwise innocent actions! (<-- yeah, that's an attempt at humor)

- JC

Well...Ok, this one time we will overlook it
Just try to control yourself in the future.

Just a suggestion, you could fill a suitable pressure vessel and apply pressure from another gas bottle, nitrogen would be good.
Then heat the bottle up to 240C needed.

sinbad,
Much safer to use a hydraulic system. Pressurised gas is very dangerous in experimental/lash-up situations.

regards
dva

I would happily live the rest of my life without hearing "ooohhhhh.... isn't that dangerous?"..... or "ooooohhhhh.... that doesn't sound safe"........
Life isn't safe and you don't get anywhere without taking chances.
Besides, you don't get any more safe than conducting an experiment from the other side of a hill while monitoring it via CCT cameras.

Over the weekend I took the slave cylinder (the 12 ton jack) apart and began to modify it for my use. I disassembled it and decided the best place to install the pressure out port would be where the hand pump used to be. I removed the check valves and threaded the pump housing for 1/4" NPT. I will attach a "T" where one side will be for my pressure gauge and the other will be out to the reaction vessel.
The I.D. of the hydraulic cylinder is ~1.25".

If I can find the parts locally, I'll install my gauge and fill the jack with some hydraulic fluid... then bleed the air out and put it between my floor jack and the bottom of my truck. It probably takes about a ton of force to lift the front of my truck, so I'll be interested in seeing how much pressure this creates.

Next stage will be building a contraption to hold the jack together under 2 to 4 tons of pressure. I'm starting to think looking for a used oxygen cylinder might be a good idea. Then I just have to weld a strong top onto it. The walls of a gas cylinder should also be able to contain any shrapnel should it toss its cookies.

PS. The term 'shrapnel' comes from Lieutenant Harry Shrapnel who figured out that an improvised cannon shot made of a tin can full of lead balls was especially effective on the battle field :-)