The cool thing about supercritical fluid.

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06-19-2005, 10:04 AM
symatech

The cool thing about supercritical fluid.

So we know that there are 3(4) states of matter: solid, liquid, gas and (plasma). But some are unaware that there exists beyond the liquid/gas phase the realm of supercritical fluids (scf). Imagine a closed container filled with liquid which is slowly being heated. As the liquid heats it expands and the density drops. While that is happening, liquid is also vaporizing which in turn increases the vapor pressure. After a given time (which depends on the liquid, temperature, and pressure) the vapor density will equal the liquid density and the clear cut boundary between liquid and gas disappears completely. You know have what is known as supercritical fluid.

What is so cool about SCF you ask? Just this: SCF will expand and contract like a gas does, but it has the solvent properties of a liquid. These properties can further be altered by adjusting the density of the SCF. So far science has been researching supercritical CO2 and H2O the most. Here are some interesting things about them:

SC CO2 - Has the ability to extract non-polar compounds from complex mixtures. Some examples would be caffeine from coffee beans, nicotine from tobacco, and fat from potato chips but leaves the taste unaltered. Obviously this could lead to healthier snack products sometime in our future. In addition to those, SC CO2 can dissolves the fat from meat, as well as pesticide and drug residues. Once these are removed, you lower the pressure and the SCF disperses as gas.

SC H2O - The most remarkable trait of SC H2O is it's ability to dissolve non-polar substances with ease. As we all know water is polar and doesn't dissolve non-polar compounds, but SC water does. The main application of this is to remove dangerous organic toxins from industrial waste by extracting them into SC water. Then oxidizing it to form harmless molecules.

I just posted this for your reading pleasure if you weren't aware of the most amazing properties of supercritical fluids. You can find this kind of info most anywhere on the internet as well as a myriad of physics and chemistry textbooks should you get bored and decide to read one :D

Hope you enjoyed it.

Johan this is for you bud, since I haven't posted anything of the like in quite some time.
06-19-2005, 10:08 AM
IronFreakX

Y arent they using it now???
06-19-2005, 10:15 AM
symatech

Quote:

Originally Posted by IronFreakX

Y arent they using it now???

It's still being studied heavily. There are so many applications of SCF that I couldn't begin to write about all of them, and they find new things about them frequently. So it will be studied for some time. I wish I knew what was on the cutting edge of SCF application today but I'm rather in the dark I'm sorry to say.
06-19-2005, 11:29 AM
nsa

I remember SCF from those temperature/pressure charts from chemistry... Doesn't SCF have to be under crazy high temps. and pressures to exist?
06-19-2005, 11:39 AM
symatech

yes very high temp and pressure. some examples:

CO2 - 304 K (31 C) @ 75atm

H2O - 647 K (374 C) @ 224atm

NH3 - 406 K (133 C) @ 73atm
06-19-2005, 12:33 PM
Kärnfysikern

Quote:

Originally Posted by symatech

Johan this is for you bud, since I haven't posted anything of the like in quite some time.

Nice. Never even knew such a thing exists acctualy. But I wonder if stuff would taste the same with fat removed by those means since fat is a "taste transporter".

BTW would you know any article about nasas new idea on launching space flights. The magnetic ramp accelerator thing?
06-19-2005, 12:35 PM
Kärnfysikern

Quote:

Originally Posted by symatech

It's still being studied heavily. There are so many applications of SCF that I couldn't begin to write about all of them, and they find new things about them frequently. So it will be studied for some time. I wish I knew what was on the cutting edge of SCF application today but I'm rather in the dark I'm sorry to say.

What other kind of applications could it have that you know of?
06-19-2005, 01:24 PM
symatech

Quote:

Originally Posted by johan

What other kind of applications could it have that you know of?

http://www.scrub.lanl.gov/html/scf/about/apps_main_nn.htm - there are a few here related to cleaning & extraction, solvent replacement, polymeric materials modification, enhanced oil recovery, and some synthesis.

http://www.azom.com/details.asp?ArticleID=1315 this page has some info on the use of SCF for nanoscale casting, and lithography.

Quote:

BTW would you know any article about nasas new idea on launching space flights. The magnetic ramp accelerator thing?

I'm afriad I don't know much about it
06-19-2005, 01:52 PM
Kärnfysikern

I keep almost no track on science news anymore :( Can never afford science mags and to lasy to search the web lol. I realy want to keep a close eye on all the different kinds of fusion that is beeing researched.

Feels like space science realy isnt progressing nowdays that is a shame. I wonder how far they have come with the crew exploration vechicle.
06-19-2005, 05:57 PM
tonytone

Quote:

Originally Posted by symatech

So we know that there are 3(4) states of matter: solid, liquid, gas and (plasma). But some are unaware that there exists beyond the liquid/gas phase the realm of supercritical fluids (scf). Imagine a closed container filled with liquid which is slowly being heated. As the liquid heats it expands and the density drops. While that is happening, liquid is also vaporizing which in turn increases the vapor pressure. After a given time (which depends on the liquid, temperature, and pressure) the vapor density will equal the liquid density and the clear cut boundary between liquid and gas disappears completely. You know have what is known as supercritical fluid.

What is so cool about SCF you ask? Just this: SCF will expand and contract like a gas does, but it has the solvent properties of a liquid. These properties can further be altered by adjusting the density of the SCF. So far science has been researching supercritical CO2 and H2O the most. Here are some interesting things about them:

SC CO2 - Has the ability to extract non-polar compounds from complex mixtures. Some examples would be caffeine from coffee beans, nicotine from tobacco, and fat from potato chips but leaves the taste unaltered. Obviously this could lead to healthier snack products sometime in our future. In addition to those, SC CO2 can dissolves the fat from meat, as well as pesticide and drug residues. Once these are removed, you lower the pressure and the SCF disperses as gas.

SC H2O - The most remarkable trait of SC H2O is it's ability to dissolve non-polar substances with ease. As we all know water is polar and doesn't dissolve non-polar compounds, but SC water does. The main application of this is to remove dangerous organic toxins from industrial waste by extracting them into SC water. Then oxidizing it to form harmless molecules.

I just posted this for your reading pleasure if you weren't aware of the most amazing properties of supercritical fluids. You can find this kind of info most anywhere on the internet as well as a myriad of physics and chemistry textbooks should you get bored and decide to read one :D

Hope you enjoyed it.

Johan this is for you bud, since I haven't posted anything of the like in quite some time.

all those chem classes are paying off, huh? keep the interesting info coming