musings on music and life

March 19, 2012

He shortage

Filed under: Chemistry — sankirnam @ 9:57 am

I came across this article (http://www.guardian.co.uk/science/2012/mar/18/helium-party-balloons-squandered) earlier while browsing reddit. This is a topic I’ve discussed for several years at length with dozens of people, and I am glad to see it finally getting attention.

Helium, as most people know, is the 2nd element in the periodic table. For more information, see the wikipedia page: http://en.wikipedia.org/wiki/Helium

Helium is the second most abundant element in the universe, but not on Earth, interestingly enough. It’s rarity on our planet is a direct result of its low molecular mass. With a mass of only 4 amu per atom (4g/mol), the average molecular velocity of helium atoms at STP is greater than the escape velocity of Earth (this can be calculated by using the ideal gas law, for those interested), meaning that any time helium is released into the atmosphere, it shoots off into space. Helium is also only produced on earth by alpha decay of heavy elements, and gets trapped underground with natural gas. Natural gas is often also found alongside crude petroleum deposits. Few places bother to separate natural gas from more valuable petroleum when discovered, often choosing to “flare off” the natural gas. Fewer places still separate the small amounts of helium from natural gas.

The article does a good job of bringing awareness of the looming helium shortage. This shortage is significant because there are certain applications of helium for which we have no adequate substitutes. For example, nuclear magnetic resonance (NMR or MRI) depends on the use of superconducting magnets . These magnets are kept superconducting by being continuously cooled with liquid helium. Liquid helium is one of the coldest substances commercially available, with a temperature of 4 K. Although there is a lot of research being conducted on making higher-temperature superconductors, at present, all practical superconductors need to be cooled with liquid He.

Synthetic chemistry blossomed in the 20th century due to the application of physical methods such as microwave spectroscopy, IR, NMR, X-ray, and others. These (especially NMR) have become indispensable to the practicing chemist since they are non-destructive characterization methods. The loss of easily available helium would be an enormous blow to the synthetic enterprise; I can’t even begin to fathom what the consequences would be. Almost all chemists in the past 30 years or so have routinely used NMR methods for characterization and even kinetic studies; losing access to NMR would be akin to losing a key vision, i.e. sight.

The only problem with the article is that it (in my opinion) incorrectly blames the shortage of helium on frivolous uses, like party balloons. This is actually a very minor part of overall helium consumption. The cause is simply that global helium consumption has exploded in the last decade or so. With more NMR spectrometers operating worldwide, and more and more labs being operated for particle physics experiments (like the LHC), it is more likely that we have increased our use of helium without being aware of it.

Suddenly, as I have being saying for years, mining the moon doesn’t seem like such a bad idea, eh?

Advertisements

Leave a Comment »

No comments yet.

RSS feed for comments on this post. TrackBack URI

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Create a free website or blog at WordPress.com.

%d bloggers like this: