Fusor Forums

Don't know if I'd ever seen one of these on a highway, before last week. Please excuse me for taking a picture while driving. A thing I do maybe once every year or two, knowing that it's not very safe behavior.

Someone's got a big welding project afoot.

I see these transports of liquid gases a number of times passing me on the highways. I have seen liquid ammonia, Carbon dioxide, oxygen, nitrogen and Argon. Of all such transports, Argon is not seen often.

Argon is an extremely inexpensive as a gas. 1% of the atmosphere and every breath we take is Argon. As such, it is a waste product of air liquification.
Liquid nitrogen is about the price of beer. An argon Refill in a cylinder is quite cheap. I have 3 different cylinders here. the largest is, of course for my TIG welder. The other two are for experimentation.

Only helium like used in party balloons, 4He, is a gas that is non-extant in usable amounts in air. Like the 3He it is a gas of "rot". To obtain 3He we must make Tritium in reactors and let it rot in a container going through its half-life to make 3He. 3He is easily separated from rotting tritium without the need for liquification. Helium 4 is a rot product, ultimately, of Uranium and its many daughters over millions of years. The only place we can obtain it on Earth is from salt and oil domes where it is trapped and collects under the earth. In theory, once this source is mined out, there can be no more helium for commerce or party balloons on this planet. Party balloon helium is rather expensive and will become more expensive over time.

Argon has blessedly replaced, for the most part, helium 4 in welding. The old heli-arc process is not as common as it once was as MIG and TIG with their far more common shield gases have stepped in for much of what was a heli-arc domain. At one time, the U.S. was the largest source of helium 4 on earth. Bill Clinton in his faulted wisdom sold off the bulk of our national helium reserves during his administration for cash. It was at this time that you started to see the small helium tanks appear in toy stores for party balloons as the market price for helium crashed with the U.S. glut onto the world market. Naturally, the price has risen considerably since then.

Depending on your source, helium prices have doubled to quadrupled since the Clinton era. I have included a chart on production which tells the story. Once the Heliarc process became widely used and during the "cold war" all production went through the roof. Once reserves were established, the production fell to near WWII levels. check the dip during Clinton's time in office. Another dip as the glut forced production and prices way down. Today, it is rare to see Heliarc used as TIG has replaced it for many applications.

Richard Hull

And lets not forget - any Helium released into the atmosphere, rises and reaches the upper regions where UV radiation ionizes and accelerates the atoms into space, forever lost from the planet. Argon, simply re-mixes and remains in the lowest regions due to its density. That greater mass of Ar also makes it possible to 'fill' an open container and displace all the air. A nice trick to use when one wants to store reactive metals and the like from oxygen.

Radium and its daughters are the sole rapid producers of 4He. All Uranium is an abysmally slow source of 4He until it reaches radium. As all helium on earth comes ultimately from uranium, virtually all of which is currently in equilibrium, it is Radium that is the fast producer. It takes a few tons of Uranium rich rock to produce 1 gram of radium, we might ask, how much 4He can a gram of radium produce in a year?

Through experiment it is determined that about 0.1cc of 4He is produced from all the radium contained in several tons of Uranium rich rock in a year. In 10,000 years that rock will struggle to produce 1 liter at STP of 4He! We note that these figures are for the fast and rapid production of 4He from radium. Science and industry uses helium at the rate of millions of cubic feet per annum.

It is interesting to note that for any given quantity of radium it takes about 6,000 years for it to rather completely decay into stable elements and helium gas. Geologically, this is like a bolt of lightning.

Thus millions of years are needed to fill a salt, oil or gas dome with enough pressurized helium to cause a helium "gusher". Helium......When it is gone, it is gone forever as an industrial use item.

Richard Hull

Similar to the truck in OP, but colder inside.

Filling densities table inspires a look at vapor pressure curve.
I think that unlike nitrogen and argon, LH2 tanks can't run at constant pressure/temperature and simply vent whatever boils off.
Anybody here ever work with the stuff?
What is the reference for 100% filling density ? Can't be water density !

On its way to the cape or space X???

Richard Hull

All I know is that it's incredibly fluffy. A litre of water has more hydrogen than a litre of LH2.

That liquid hydrogen is so "fluffy" is exactly why it was not used to fuel the first stage of the Saturn V rocket; that used kerosene (and, of course, LOX.) This enabled the Sat V to climb out of the earth's gravity well somewhat faster (due to greater Impulse due to kerosene's far greater density) than a hydrogen fueled rocket allowing a greater payload to reach orbit for equal volume rocket stages. If someone simply looked at ejection velocity they'd favor hydrogen (as did NASA for the Saturn's second stage (being out of the Earth's gravity well, density and stage volume isn't such an issue.)) This extremely elementary fact was totally forgotten by NASA when it designed the shuttle with its hydrogen based propellant with terribly tragic consequences; further, this fundamental error resulted in the shuttle losing out on getting almost 5% more payload into orbit for each launch had they used kerosene.