Naked Science Forum
Non Life Sciences => Chemistry => Topic started by: dave beagle on 02/11/2011 12:01:02
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dave beagle asked the Naked Scientists:
Hello Dr Chris could you and the team tell me how helium is made as this is a finite resource?
What are we going to do when this runs out as it is used in many important machines??
Thanks big fella.
What do you think?
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Helium is in some senses a finite resource. It is constantly, but very slowly, being produced by radioactive decay of all of the uranium and thorium on/in the Earth. But it is also constantly, but equally slowly, being lost from the Earth's atmosphere because it is so light that gravity cannot hold helium when it is energized by solar interactions with the outer atmosphere.
For a long time it was thought that there was almost no helium on the Earth, but then it was found in fairly decent concentration in some natural gas wells in the southern states of the USA. Helium can be trapped and contained below a layer of particularly impervious rock in a dome-shaped formation (exactly the same as for oil/flammable gas wells). So millions of years' worth of helium got trapped in these places.
Nearly all of the world's commercially exploitable helium comes from these wells, and nearly all of the helium containing wells are in the USA, though there are some in Russia and Eastern Europe. This helium is a very scarce and precious resource, and is jealously guarded and controlled by the US government. It may well be exhausted in the next few decades.
However, there is enough helium in the atmosphere to maintain a steady state (escape rate from atmosphere = escape rate from rocks to atmosphere) of about 5.2 molecules per million. So when we run out of the concentrated helium, there will be a much larger-- huge even -- reservoir of helium remaining. But it will be very much more expensive to isolate and concentrate.
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If the universe if finite, the helium from this universe has to be finite as well.
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"and is jealously guarded and controlled by the US government. It may well be exhausted in the next few decades."
No, it isn't. They used to, but they though it was a bit communist so they flooded the market with it instead. Lot's of people had balloons at kids' parties.
Now it's gone and the price has risen again.
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Keep in mind that there are two types of helium.
3He and 4He.
The 3He is created by fusion in the sun and other stars. Much of our 4He available is from radioactive decay as mentioned above.
Many of the fusion energy experiments are being done with the very rare (on Earth) 3He.
Helium is still cheap in the USA and is used for birthday parties and balloons. In a sense, it would be difficult to store all the helium that is recovered from the natural gas wells. But, at some point, at least the easily accessible helium will be exhausted. Do other countries have it, but just haven't invested in the recovery?
There are many uses of helium without a good substitute, such as deep water diving, and some refrigeration. Personally I think it would be a mistake to not try to preserve more for the future.
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"In a sense, it would be difficult to store all the helium that is recovered from the natural gas wells. "
It was perfectly possible, and they did, but they decided to stop doing so.
This seems very shortsighted to me.
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CliffordK:
Do other countries have it, but just haven't invested in the recovery?
On the one hand I think it is fairly clear that other countries must have some helium in their natural gas wells, and that by and large they have not invested in recovery infrastructure. On the other hand I have also read somewhere -- cannot find source -- that American gas wells, especially Alabama/Oklahoma area, have had natural gas compositions unusually rich in helium. I know that they are talking at present about helium recovery from our Australian gas fields -- do not know how rich they would be, whether it would be economically viable, and whether they have got beyond talk.
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(Added later:)
Found this website
http://www.metts.com.au/lng-carbon-footprints-cdm.html (http://www.metts.com.au/lng-carbon-footprints-cdm.html)
which includes the following passage (to save you reading thru a bunch of stuff irrelevant to this topic):
Helium separation and recovery
Helium is recovered from natural gas resources. Natural gas can contain helium concentrations ranging from zero to over six percent (v/v). Helium has become an important strategic gaseous mineral and recent shortages have seen the price of helium double [1].
Helium production has been dominated by the United States (US). The US has (had) a series of gas wells in the south-west of the country that had exceptionally high helium concentrations. The helium was associated with carbon dioxide, nitrogen and hydrocarbons. In some instances helium was the only recovered product from the wells. In the last twenty years, the dominance of the US in helium production and supply has diminished. Now such countries as Russia, Australia, Algeria and Qatar have viable helium production units. In 2008 the US still produced around 80% of the World’s helium (and has substantial stored reserves) but this percentage is expected to fall with new plants coming on-line in Algeria, Australia and Qatar [1 & 2].
The change from recovering helium from wells with high helium concentrations to wells with low helium (and now very low concentrations) has come about from the availability of LNG Off-gas with readily recoverable helium contents and the development of new technologies that can be applied to helium separation such as pressure swing adsorption (PSA).
Gas wells with helium concentrations of greater than 0·3% can be commercialised essentially for their helium content [3]. Other natural gas reserves with helium concentrations as low as 0·04% can have viable helium by-product streams. (In India, the processing of one such natural gas resource promises to make India self-sufficient with the strategic mineral helium [4].) With very low concentrations of helium in raw natural gas, the economic driver in making the LNG Off-gas a viable helium resource, is the very high concentration factor that can come through stripping out virtually all other gasses in the LNG process combined with large total throughputs of total gas through the LNG system.
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no we are using it too quickly it was on q.i i believer exscuse my dodgy memory but i think it cools something very important like nuclear reactors so when we run out we could be in trouble.
soemthing along those lines
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Thanks for the description damocles.
I knew that they did extra purification for LNG production, and I can imagine that anything that boils at below −161 °C could be moderately concentrated with Helium.
And, of course, LNG is important for bulk shipping of Natural Gas, especially where there are no pipelines available.
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I cannot recall where I read this but last year there was an article about the true value of Helium and how underpriced it was, considering its usefulness and the earth's dwindling resources they should be selling kids balloons at about $60 each.