I built a small extraction chamber for processing materials with supercritical CO2.
Please refer to my previous videos for more information about supercritical co2:
http://www.youtube.com/watch?v=-gCTKteN5Y4
http://www.youtube.com/watch?v=TvmM6qa2a90
PDF discussing vanilla extraction with SC CO2:
http://www.redalyc.org/pdf/482/48221175004.pdf
A possible solution to the Glass tubing is to press fit the glass tubing in the acrylic. The Acrylic will re-enforce the glass. You probably need to cool down the glass tubing and warm up the acrylic to get really snug fit. Although, I think using Stainless would work much better since you can use a much larger chamber to store the raw material in. I would suggest using cotton instead of fiberglass since there is a risk of micro-particles from the glass being deposited in the extracted product, which make be a concern if you use it in food.
ReplyDeleteI am curious in your previous videos extracting caffeine from coffee beans, what was the experiment you where going to do with the extracted caffeine?
TechGuy, I haven't used the caffeine for anything. I was mostly interested in the extraction process itself.
ReplyDeleteHi. Speaking of your acquired extraction skills: I would love to see your take on algae oil production.
ReplyDeleteFrom what I've read, growing the algae should be fairly trivial. Once you have a crop, you can dry them and obtain the algae oil using super-critical fluid extraction. This oil can later be distilled into fuel.
If I had your equipment, I'd give it a try. Might take a while, but wow - what a feat.
Hi Ben,
ReplyDeleteI have been digging s bit for the acrylic problem and then my friend Madison came up with the material Alon.
Alon is a very though kinda glass that can stop bullits, and it doesn't let gas in.
I don't know the exact stats and if ya can even get it. But I heart it is good for usage in though chamber situations.
http://en.wikipedia.org/wiki/Aluminium_oxynitride
Re: Flange warping issue in Stainless CO2 chamber
ReplyDeleteTo minimize warpage:
Pre-heat the parts to reduce expansion during welding. Preheating also helps reduce the strength loss issues caused by welding.
Machine the parts to near press fit. When The Weld pool cools it shrinks pulling in on any gap space. if you can fit your parts with no gaps there it harder for the parts to warp.
Stitch weld the pieces by only putting a small bead in an area and the weld the opposite side.
Post heat the welded pieces after welding is completed. This will reduce internal stress and can reduce some warpage as internal stresses are reduced. Welded pieces will slowly reduce internal stress but this can take a decade for mild steel at room temperature. The hotter you can post-heat the shorter the time it will take for the metal will relax. When cooling its important to slowly reduce the temperature, about 100 Degress F per hour so that the part cools evenly. Post-heating will also restore most of the strength loss caused by welding. If you don't have a heat treat oven, You can post heat your part in a kitchen oven or a gas fired barbecue grill. Its not as fast but it will speed up the reduction of internal stresses.
If you did excessive welding on the flange, where there is a significant amount of weld bead (ie you added 1/4 inch of weld bead buildup) then preheating and post-heating is probably not going to help much. because the weld pool will naturally curve the flange. The only option would be to clamp the flange on a solid flat piece of steel, preferably with a thick steel ring on the welded side so that the clamping force is even. That said its probably just easier to chuck it in a lathe and resurface the flange flat as you mention in the video.
TechGuy, thanks! That's great advice.
ReplyDelete