4 ms·

The overall amount of helium in the atmosphere is still more than enough for the foreseeable future, and it could be extracted (albeit at high energy cost) by a

The overall amount of helium in the atmosphere is still more than enough for the foreseeable future, and it could be extracted (albeit at high energy cost) by augmenting existing air separation units (ASU's). Of course natural gas wells currently provide an easier to extract source, seeing as the concentration there is way higher.

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nradov 7mo ago
Helium is only 5ppm in the atmosphere. Extracting useful quantities of it that way will probably never be economically viable. In other words, if for some reason we can no longer get helium from natural gas wells then it will be cheaper to just let patients die instead of doing cryogenic distillation of helium from the atmosphere to run MRI machines.
- zozbot234 7mo ago
  We are already separating out the majority elements from air via ASU plants, so we should compare the abundance of helium in what is left from typical extraction. And that looks quite technically viable, if obviously uneconomic at present.
  - ted_dunning 7mo ago
    This is a very good point. Oxygen, nitrogen, CO2 and argon make up 99.94% of the atmosphere. The remaining 0.06% has 5ppm is nearly 1% helium. That's up 200x from the original concentration and is well above the 0.3% that is sometimes quoted as the limit for economic extraction of helium (and well below the 7% of some natural gas). Furthermore, the leftover gas is also already cold. It is absolutely true that 85K isn't very close to the boiling point of helium, it is a lot closer than starting at the temperature of gas at the well head. The gotcha is almost certainly going to be that an ASU probably doesn't liquify most of the gas it takes in. That means that the exhaust gas will only be slightly enhanced.
- XorNot 7mo ago
  In a world of extremely cheap solar electricity pushing grid prices negative, a lot of things might be a lot more economical then conventionally thought though - particularly when you factor in the desire to get a full return on industrial manufacturing of panels.
  - rootusrootus 7mo ago
    For me personally, this is one of the most promising aspects of solar that I hope to see in the future. There are many, many things we could do but currently do not because the energy cost is not worth it. Push the energy cost to zero, or even below, and it will be interesting to see what new things become abundant.
    - don_esteban 7mo ago
      CO2 capture from the atmosphere, turning it into hydrocarbons. All the solar panels/wind farms combined have quite large surface that might be useful for the capture. Just need to figure out the mechanism to do it. Easy-peasy, right? :-)
- tliltocatl 7mo ago
  MRI could switch to LH2. Yes, it's explosive and higher boiling temperature so would not support as high field and incompatible with currently used semiconductors. But it's doable. Plenty of other important uses (i. e. semiconductors and lasers) where it is much more irreplaceable.
  - miduil 7mo ago
    New MRI only use 7 Liters (25 Cups) instead of ~1500L (~330Gallons) of liquid Helium due to better sealed magnets. https://mriquestions.com/uploads/3/4/5/7/34572113/philips_blue_seal_brochure.pdf https://mriquestions.com/uploads/3/4/5/7/34572113/philips_bl...

deleted 7mo ago

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nradov 7mo ago

Helium is only 5ppm in the atmosphere. Extracting useful quantities of it that way will probably never be economically viable. In other words, if for some reason we can no longer get helium from natural gas wells then it will be cheaper to just let patients die instead of doing cryogenic distillation of helium from the atmosphere to run MRI machines.

zozbot234 7mo ago
We are already separating out the majority elements from air via ASU plants, so we should compare the abundance of helium in what is left from typical extraction. And that looks quite technically viable, if obviously uneconomic at present.
- ted_dunning 7mo ago
  This is a very good point. Oxygen, nitrogen, CO2 and argon make up 99.94% of the atmosphere. The remaining 0.06% has 5ppm is nearly 1% helium. That's up 200x from the original concentration and is well above the 0.3% that is sometimes quoted as the limit for economic extraction of helium (and well below the 7% of some natural gas). Furthermore, the leftover gas is also already cold. It is absolutely true that 85K isn't very close to the boiling point of helium, it is a lot closer than starting at the temperature of gas at the well head. The gotcha is almost certainly going to be that an ASU probably doesn't liquify most of the gas it takes in. That means that the exhaust gas will only be slightly enhanced.
XorNot 7mo ago
In a world of extremely cheap solar electricity pushing grid prices negative, a lot of things might be a lot more economical then conventionally thought though - particularly when you factor in the desire to get a full return on industrial manufacturing of panels.
- rootusrootus 7mo ago
  For me personally, this is one of the most promising aspects of solar that I hope to see in the future. There are many, many things we could do but currently do not because the energy cost is not worth it. Push the energy cost to zero, or even below, and it will be interesting to see what new things become abundant.
  - don_esteban 7mo ago
    CO2 capture from the atmosphere, turning it into hydrocarbons. All the solar panels/wind farms combined have quite large surface that might be useful for the capture. Just need to figure out the mechanism to do it. Easy-peasy, right? :-)
tliltocatl 7mo ago
MRI could switch to LH2. Yes, it's explosive and higher boiling temperature so would not support as high field and incompatible with currently used semiconductors. But it's doable. Plenty of other important uses (i. e. semiconductors and lasers) where it is much more irreplaceable.
- miduil 7mo ago
  New MRI only use 7 Liters (25 Cups) instead of ~1500L (~330Gallons) of liquid Helium due to better sealed magnets. https://mriquestions.com/uploads/3/4/5/7/34572113/philips_blue_seal_brochure.pdf https://mriquestions.com/uploads/3/4/5/7/34572113/philips_bl...