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Quince
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Is it possible to build a DIY supercritical CO2 extractor?
I've seen a guy make a DIY electron microscope, so I figure anything can be done at home. Anyone heard of DIY for a supercritical CO2 extractor, or
have any pointers to design information?
\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
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DrP
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You could do it if you had an autoclave. Get the mixture right and crank up the pressure until you get the super critical fluid??
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Quince
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That just reaches the conditions. How do you actually circulate it for extraction?
\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
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roamingnome
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This is a machine i would like to build too, but its a bit on the horizion.
Working with butane, which i still havent done well, is simmilar. That is to say, would the fluid flow simply to exspand on the other end. A heat
gradient flow. Putting CO2 gas pressure on one end of the apparatus will certianly cuase a flow. The dry solid would turn liquid after 5 atm about,
and shoot out of a tube into what you want to extract.
See if i can pull up some actual graphs and phase diagrams.
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roamingnome
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http://www.leisurepro.com/ProductImage/MXA35.html?PopUp=1
add to the wish list a scuba tank air compressor, gas or electric your choice....
essential for lab needs
the pressure needed is 73 ATM or 1073 PSI ..this is high but not impossibly high to obtain...
super critcal fluids have no surface tension or very little ..so it should flow around
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a_bab
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Quince, where did you find about the electronic microscope building? If it's a website could you post it please?
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Quince
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Well, it still cost him $10000 in parts, but I'm sure the wise guys around here could do it for less.
http://www.microscopy-uk.org.uk/mag/indexmag.html?http://www...
Note that he only achieved 20000 magnification and resolution of 20 nm.
[Edited on 7-12-2006 by Quince]
\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
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Organikum
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If I am not mistaken then a raster-tunnel microscope would be easier and cheaper to build. I believe it has been done already.
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Organikum
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A CO2 SC extractor is easy and cheap as CO2 bottles are common articles for pubs.
If recycling the CO2 is intended it gets more complicated and expensive though, but there is no need to do so as long this is not a real big scale
operation.
There are two types of CO2 bottles on the market: One has only one outlet on top - this kind of bottle must be turned on top for use and the other
kind has two outlets, one connected to a tube leading to the bottom of the bottle to withdraw liquid CO2. The second kind is preferred for the easier
handling.
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Quince
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A scanning one has been built for about $500 I believe using piezo elements hooked up to the probe, and some simple electronics.
\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
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Quince
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| Quote: | Originally posted by Organikum
A CO2 SC extractor is easy and cheap as CO2 bottles are common articles for pubs. |
Organikum, you've just pointed out a source of compressed CO2. That doesn't tell me how to make an extractor.
\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
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Organikum
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Perhaps you try the patent office?
If it is about plant material you can also just Google for butane or CO2 estraction of cannabis/marihuana.
Hint: You need a tube with a nozzle on one end. Thats so easy even stoner get it going.
[Edited on 9-12-2006 by Organikum]
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Quince
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The hell is your problem? Now you're implying I'm trying to extract drugs.
Go fuck yourself.
\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
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Organikum
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Well I fucked myself often enough.....
I pointed you to a working simplified supercritical extraction method for plant material, the fact that it was developed for marihuana doesnt make it
less valid. I did not in any way say that you want to extract drugs, but there wouldnt be anything bad with this in my eyes anyways.
The problem is solely at your side, you are a bit irritable it seems, havent you taken your medication?
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Quince
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The only CO2 I've been able to find in consumer outlets is the soda maker cartridges, which are simply too small at $1 a piece to be practical.
\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
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Magpie
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My son brought home a 20 oz CO2 cartridge for use in paintball. With his permission I put it to a higher use in my lab. The paintball dealer even
sold me a nifty stainless steel valve for a few bucks. This plus a couple brass fittings and I now have CO2 on demand. See photo below.
Building the piping system for a supercritical CO2 recirculation system doesn't seem like a real challenge, as you are only talking around 70 bar,
correct? Buying a pump/compressor for this may be expensive, however.
The single most important condition for a successful synthesis is good mixing - Nicodem
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unionised
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You don't really need a compressor. Connect the vessel directly to a cylinder of liquid CO2, cool it to "distill" the CO2 into the vesssel. Seal it
and let it warm up. One of 3 things will happen. If you haven't got enough CO2 then you just get the vessel full of CO2 vapour. If you have too much
CO2 the vessel will, quite possibly burst. Somewher in between you will get supercritical CO2.
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Quince
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unionized, that's not particularly helpful.
Finding a safety release valve appropriate for the pressure, and making joints that can withstand it on all the equipment, seem to me non-trivial
tasks.
By the way, say you have your cylinder filled with supercritical CO2. Then what? How do you actually do an extraction? Also, how much CO2 is needed
in general to extract say a gram of essential oils completely? Perhaps without some sort of recirculating extraction, this would be a very expensive
method needing huge amounts of gas. In that case a compressor seems to be unavoidable...
[Edited on 11-12-2006 by Quince]
\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
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unionised
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How helpful it is depends on whether or not you accept that I was just pointing out that, even without a compressor, you can quite easilly burst
things while playing this game.
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Quince
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Well, so could the jar of yellowing NG that was sitting for a few months by my bedside.
\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
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unionised
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Top ten of things not to post on a public website.
#1 I make explosives carelessly
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Quince
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I don't play around with energetic substances anymore. There're no suitable testing grounds around here. That's why I had it as long.
\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
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roamingnome
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paintball is a versitle sport, the game itself is fun and the equipment is handy. I use 4500 psi compressed air though. The reason for a compressor
is that i want to process tons of straw. the compressor needed would be large and powered by solar energy.
The fractionation of valuable wax products from wheat straw using CO2
http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArtic...
[Edited on 13-12-2006 by roamingnome]
[Edited on 13-12-2006 by roamingnome]
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chemrox
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building a supercritical extractor- first thoughts
I want to build a supercritical extractor too. It's a future project but have given it a little thought. I got some pictures of one that a
glassblower aquaintence built for an engineer who was working for a coffee company. It was a bench scale setup. It appeared to be a heavy walled
stainless cylinder .. ie a pressure vessel.
As I see it there are three key components or aspects to it:
1) one has to be able to load solids into it .. a pressure tight screw seal of some kind I think
2) it needs a fluid inlet that will accomodate standard gas fittings.
3) it needs an outlet that will release the fluid quickly enough that the fluid is outside the vessel when it flashes off
I realize these parameters may be obvious to most of us and in that sense trivial. However, this is as far as I've gotten with design. I have a
machinist who will make the device if we can give him exact specs.
I want to be able to handle both butane and CO2. I have no immediate plans for the CO2 side but it would be a shame not to design for it when we have
free labor available to us.
The biggest problem I'm having is coming up with the outlet specs. I'd like to get an off the shelf valve or stopcock for this. Not atn all clear on
where to look except the big industrial supply catalogs like Mcmann, etc.
My glassblower friend has not offered more information since we passed on buying the old prototype and since its business to him we can't ask .. or
shouldn't anyway.
I'm hoping this thread will continue and brainstorming here may lead to a good solution or set of them.
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Magpie
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| Quote: |
1) one has to be able to load solids into it .. a pressure tight screw seal of some kind I think
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This statement confused me a little. At first I thought you were planning a continuous process. But it will be batch, right? You are just saying
that you need a hatch or port that is resealable. This is not a big problem. The usual solution is a flanged head or port that is resealed using a
gasket and bolts.
| Quote: |
2) it needs a fluid inlet that will accomodate standard gas fittings
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This is no problem at all. Use ball valves to seal off connections.
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3) it needs an outlet that will release the fluid quickly enough that the fluid is outside the vessel when it flashes off
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I don't understand this requirement. The fluid will not change phase until the pressure is low enough. This won't happen until it is on the
downstream side of your outlet valve. For rough control a simple ball valve would be fine. For fine control a globe (or needle) valve would be
used.
I still think your biggest problem will be recirculation. There are pumps that can do this but...how big is your budget? 
The single most important condition for a successful synthesis is good mixing - Nicodem
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