4 ms·
Naively, 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
by Boxxed 8y ago
Naively, 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?
- thaumasiotes 8y agoFurther? That's the same idea.
- ant6n 8y agoThe difference is liquifying "to the boiling point of the element with the 2nd lowest boiling temperature" (likely Neon @ 27K) and "liquifying down to Nitrogen" (77K).
- thaumasiotes 8y agoAccording to https://en.wikipedia.org/wiki/Natural-gas_processing https://en.wikipedia.org/wiki/Natural-gas_processing , the helium is recovered from natural gas during the phase in which nitrogen is removed. Natural gas has very different content compared to the atmosphere. Let's also note that even ignoring the specific details of the process, what you're proposing is to use a pipeline which produces helium as a side effect of its intended use of producing methane, and which is usually run on a mixture of gases that is 1% or more helium, and apply it to a mixture of gases which will produce no methane and is 0.0005% helium. The helium is nearly worthless and there's barely any to harvest in the first place; there is no possible way for this to be economical.
- ant6n 8y agoWell, the idea is to produce Helium as a by-product of producing liquid nitrogen. But indeed, the numbers may not work out: About 8 million tons of liquid nitrogen is produced per year, growing 5% every year [1], largely from Cryogenic distillation. By mass, the ratio of Nitrogen and Helium in air is about 1e6 [2]. So that means, about 8 tons would be produced, which is 3.5 orders of magnitude away from the current size of the market (like 30 thousand tons). But it may be possible to use non-cryogenic processes [3] to increase the ratio of Helium in the air before separating out the nitrogen. So between the increase of the nitrogen market, the decrease in demand if Helium gets more expensive when traditional sources run out, and better processes, this means that Helium will likely continue to be available for very valuable use cases almost indefinitely. [1] https://www.grandviewresearch.com/industry-analysis/liquid-nitrogen-market https://www.grandviewresearch.com/industry-analysis/liquid-n... [2] http://www.uigi.com/air.html http://www.uigi.com/air.html [3] https://en.wikipedia.org/wiki/Air_separation https://en.wikipedia.org/wiki/Air_separation
- mehrdadn 8y agoI'd guess you'd still have problem separating helium from hydrogen?
- amluto 8y agoThat seems relatively straightforward to solve chemically. Hydrogen can be adsorbed by many different materials. Or you could add just the right amount of oxygen to burn the hydrogen and then condense the water out.
- zrm 8y agoCouldn't this also be done for the other reactive components (especially nitrogen and oxygen) before cooling the gas? Removing ~99% of the mass ahead of time would require that much less energy for cooling.
- londons_explore 8y agoLiquid oxygen and nitrogen both have some commercial value. The tricky but is the liquidation process only liquifies some small fraction of the gas. The rest remains as a gas, so you now have "helium enriched" air, but it is still a very small percentage helium.
- InclinedPlane 8y agoYes, that's how you could do it by modifying liquefaction plants that can produce Neon. In theory, you could take the leftovers after separating out Neon and you'd have a small amount of Helium. As I mentioned, at 5 ppm that doesn't give you much Helium, and you still need to purify it.