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The atmospheric noble gas concentrations, in ppmv: Helium 5.24 Neon 18.18 Krypton 1.14 Argon 9340 Xenon 0.087 http://www.gly.uga.edu/railsback/Fundamental
by philipkglass 8y ago
The atmospheric noble gas concentrations, in ppmv:
Helium 5.24
Neon 18.18
Krypton 1.14
Argon 9340
Xenon 0.087
http://www.gly.uga.edu/railsback/Fundamentals/AtmosphereCompIII.pdf http://www.gly.uga.edu/railsback/Fundamentals/AtmosphereComp...
Krypton is rarer in the atmosphere than helium (by molar/volume concentration), though more abundant by mass. Krypton is commercially produced by atmospheric separation. I would therefore expect helium sourced by air separation to cost roughly 1/4-1/5 the cost of krypton production, per liter, or 4-5 times as much per gram. A quick search on Google shows krypton at 65 cents per liter in the early 2000s (according to an article about windowpane gas filling). An Alibaba search indicates that 10-15 cents per liter may be more typical now.
If those krypton prices are accurate, and I haven't made any major mistakes with my helium ballparking, I would expect that applications like helium filled hard drives would see only a tiny cost increase should they be forced to use helium separated from the atmosphere. I think that most cryogenic cooling applications would have to move to closed-cycle reuse of helium. I don't know about welding and leak testing.
EDIT: "The Energy-Related Applications of Helium", 1980 report from Los Alamos National Laboratory, specifically considers helium production from atmospheric separation and from lean natural gas streams in section X.
https://www.osti.gov/servlets/purl/5141581 https://www.osti.gov/servlets/purl/5141581
A.W. Francis has discussed the recovery of helium from the atmosphere by conventional methods. He predicts that, for helium produced from the atmosphere as a by-product from air separation plants, the cost would lie in the range of $200 to $300 per Mcf in 1973 dollars (over ten times present
cost).
...
To go further and separate helium by similar techniques but with helium as the primary product would raise the cost by more than another order of magnitude to about $7000 Mcf in 1980 dollars.
Apparently one Mcf is 28,317 liters in SI units. That's 24.7 cents per liter of helium from the atmosphere in 1980 dollars, or 80 cents per liter in CPI-adjusted 2018 dollars.
- criddell 8y agoHelium is so light, won't it rise to the top of the atmosphere? Wouldn't that make it more difficult to extract from the atmosphere?
- saagarjha 8y agoHelium is constantly produced by radioactive decay in the Earth’s crust. I’d assume that this is the helium that’s found in the atmosphere; the rest probably escapes.
- philipkglass 8y agoEarth's atmosphere does not exhibit notable stratification by molecular weight until about 100 km up. The lower well-mixed portion is called the homosphere, and it is where these standard atmospheric composition values are measured. This near-uniform composition is also why, for instance, chlorofluorocarbons emitted at the surface reach the ozone layer and decompose it catalytically, even though their molecular weight is much greater than that of air.
- garmaine 8y agoIt's not rising to the top of the atmosphere per se, but rather that atomic helium is so light that at atmospheric temperature a significant percentage of individual atoms are moving at Earth's escape velocity. Usually they bounce into something else, but there's always some lucky few that make their way through the upper atmosphere... and keep going. That's why, for example, Saturn's atmosphere is 25% helium and 75% hydrogen, but Saturn's moon Titan is basically all nitrogen-methane. Which is also the real answer about helium. Hydrogen we have in near-infinite supply by breaking chemical bonds (e.g. in water). Helium doesn't react with anything, so so the small amount trapped in oil and natural gas deposits from Earth's radioactivity over billions of years is all we have. After that... we'd better start investing in outer solar system mining operations, skimming the atmospheres of gas giants. I, for one, look forward to a future working the gas mines.
- InclinedPlane 8y agoThis is a hugely flawed analysis. Noble gases are extracted from air through liquefaction, which requires dropping the temperature of air to the point where certain component gases are liquid, allowing them to be separated off. Krypton has a boiling point of 120 Kelvin, far higher than even Oxygen (90 K) or Nitrogen (77 K), making it trivial to extract Krypton at low cost from the atmosphere in any air liquefaction facility also set up to separate Oxygen and Nitrogen (which is basically all of them). Helium, however, boils at 4 Kelvin. It is not merely cryogenic, it is super cryogenic, and it can only be separated from air via liquefaction at extremely low temperatures. Instead, the method that is actually used to produce almost all Helium is to use natural gas (which contains as much as 7% Helium) and then separate out all of the stuff that isn't Helium (starting with the hydrocarbons, of course). This makes it possible to produce 99.995% pure "grade-A" Helium fairly cost effectively. Every cubic meter of natural gas processed could yield up to 70 liters of grade-A Helium. Compare that to processing air, where every cubic meter of air processed would yield just 5 milliliters of low grade Helium. And Helium isn't valuable enough to simply run those plants and throw away the other gases produced. By some estimates, if all of the Neon production facilities were modified to produce Helium as well then we might be able to meet 1/1000th of the world's Helium demand, so this is not a near-term solution to the problem, even if it might be able to produce the gas inexpensively.
- Boxxed 8y agoNaively, couldn't you extract helium by liquifying everything else and taking the leftover gas? So instead of cooling to 4 kelvin, cool to the boiling point of the element with the 2nd lowest boiling temperature. Or is that not helpful because that happens to be very low too?
- ant6n 8y agoEven further, shouldn't it only be necessary to liquefy down to Nitrogen, which should leave some gas that has a very high percentage of helium, and then use the same method that's used in separation of natural gas and Helium?
- 8y ago
- HarryHirsch 8y agoYou wonder about krypton and xenon, these are gases with only speciality applications and are probably minor byproducts from an air liquefaction plant. The market for helium is much much larger. To ramp up production you'd have to build a new plant, and pay for it only through the sale of minor noble gases, the cross-subsidy from nitrogen and oxygen suddenly disappeared. Markets involving joint products are funny things.
- restallus 8y agoKrypton is relatively cheap because, while it is produced by atmospheric distillation, it is a by-product of oxygen/nitrogen production. The boiling point of oxygen is -183 °C, and the boiling point of krypton is -153 °C. This means that when you distill air and obtain liquid oxygen, krypton will necessarily also be obtained as a liquid. Helium, however, has the very low boiling point of -267 °C. Commercial, high-scale production of oxygen doesn't even approach this temperature, so helium will never be distilled and instead be vented as a gas along with a residual air stream. The point is that the price of krypton is actually the marginal cost of producing it from an existing process, while the price of helium will approach the cost of energy required to extract it, which can be calculated and is quite high.
- dopamean 8y agoI've got a really dumb question that maybe you can answer. Keep in mind the last time I was in a chemistry class was 10th grade (half my life ago)... How is the boiling point of any of these elements determined? I cant imagine that we got some helium in its gaseous form and cooled it down below -267 degrees and then heated it up slowly to find out. Is there something about it's atomic makeup that allows that number to just be calculated? Thanks.
- garmaine 8y ago> How is the boiling point of any of these elements determined? I cant imagine that we got some helium in its gaseous form and cooled it down below -267 degrees and then heated it up slowly to find out. Why not? That's relatively easy to do in any moderately equipped physics lab.
- thaumasiotes 8y ago> Is there something about it's atomic makeup that allows that number to just be calculated? Yes, of course, but sadly we don't know how to do that.
- dnautics 8y agoHelium is extra special because some quantum weirdness happens, e.g. superfluid things
- ridgeguy 8y agoOT, but kind of interesting - Xe, one of the 'inert' gases you've listed, is a remarkably effective and safe general anesthetic as well as a cardio- and neuroprotective agent for some kinds of ischemic events [1]. Still a little weird to those of us who studied chemistry when the 'noble gases' were famously reluctant to mingle. [1] https://en.wikipedia.org/wiki/Xenon#Anesthesia https://en.wikipedia.org/wiki/Xenon#Anesthesia