Possible eco-safe parts degreaser

http://science.nasa.gov/headlines/y2003/20aug_supercriticalco2.htm?aol786992
tells of supercritical CO2 used as a solvent to harvest various chemicals from
Martian rock. It might be a good degreaser, and when cooled from 30 C + to ambient, and the pressure released, the dissolved matter drops out. When vented, it is much more benign than, say, varsol, or benzene.
But it requires a pressure chamber. However, a vapor degreaser requires a vapor chamber. One can leak, the other can blow up. Take your pick. I think a pressure chamber can be made safe and the energy input to it controlled.
Yours,
Doug Goncz, Replikon Research, Seven Corners, VA The hormones work at different speeds. In a fight-or-flight scenario, glucocorticoids are the ones drawing up blueprints for new aircraft carriers; epinephrine is the one handing out guns.
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Please tell me if you plan to move to the UK, I want to stay far away from you... For tiny parts, maybe. A 50cm cube at 70 atmospheres, the force on one of the sides will be around 10 tons/square meter (at 1 atm), that's 175 tons.
And you need a high pressure storage tank, and a big compressor to pump away the cleaner.
With the added fun that even a slow (non-explosive) leak will provide enough CO2 to kill you stone dead, even in a very large room.
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Doug Goncz wrote:

No, I don't think you need a chamber at all. I've heard of this being done with standard CO2 fire extinguishers. (Of course, after use, you have to get them refilled.) Note that keeping CO2 liquid at room temperature requires pressure of about 870 PSI!
Jon
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That is how they make cheetoes.
They fry the potato starch in vegetable oil, and then use liquid CO2 to remove and recover the oil.
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I wonder.. does anyone know if there exists a chemical that's supercritical at STP?
Tim
-- In the immortal words of Ned Flanders: "No foot longs!" Website @ http://webpages.charter.net/dawill/tmoranwms

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I'm pretty sure xenon and some of the other noble gases. Problem is that at stp they are so far above the critical temps that the density is back down to like a gas. Don't know of anything whose critical temp and pressure are really close to stp.
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I believe ethane would be a near match to ST, at about 660 psi vapor pressure and Tc = 305.3 K. To get critical at both ST and SP, maybe something like a Freon could be designed. Remember, to keep it supercritical it has to be contained, even if there is no net pressure difference. There is a concentration gradient, and when hydrocarbons boil, they call it "flashing" so there is energy at supercritical to make a fast transition, with what is left in the pot necessarily ending up colder than it started, but at the same pressure.
Add a little ultrasound to that and you've really got a cleaner! Forget CO2. We need a nonpolar Freon type thingie, or a hydrocarbon. Go the other way, you got propane, butane, and decane. Let me check: Nope, too hot.
I was unable to access chemistry.uttyler.edu/~pchem/fall/lectures/num11.ppt
Oh, oh. Edit box malf. AOL sux, I know.
Yours,
Doug Goncz, Replikon Research, Seven Corners, VA
The hormones work at different speeds: In a fight-or-flight scenario, glucocorticoids are the ones drawing up blueprints for new aircraft carriers; epinephrine is the one handing out guns.
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um, make that
... it started, but at ambient pressure.
ok?
Yours,
Doug Goncz Replikon Research (via aol.com)
Nuclear weapons are just Pu's way of ensuring that plenty of Pu will be available for The Next Big Experiment, outlined in a post to sci.physics.research at Google Groups under "supercritical"
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Wow! The top of my head just blew off an my brains are now coming out of my ears. This is an EXCELLENT question, Ted. I will refine it in a reply to my own post.
Yours,
Doug Goncz Replikon Research (via aol.com)
Nuclear weapons are just Pu's way of ensuring that plenty of Pu will be available for The Next Big Experiment, outlined in a post to sci.physics.research at Google Groups under "supercritical"
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http://www.chipsbooks.com/superflu.htm
Supercritical Fluid Technology in Materials Science and Engineering
This reference analyzes the chemical reactions, structures, and fundamental properties of supercritical fluid systems for the production of new compounds, nanomaterials, fibers, and films including tables displaying the physical parameters of commonly used supercritical solvents      I'll ask my librarian for a loan.
Yours,
Doug Goncz, Replikon Research, Seven Corners, VA
The hormones work at different speeds: In a fight-or-flight scenario, glucocorticoids are the ones drawing up blueprints for new aircraft carriers; epinephrine is the one handing out guns.
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