When will the Argon shortage end?

[WobblyHand]

James Prescott Joule would spit out his single malt hearing that business about PV=NRT not applying to hydrogen. It exhibits some weird effects when forcing it through thin films or filters, but the change in temperature still follows the ideal gas law.

At room temperature, all gases except hydrogen, helium, and neon cool upon expansion by the Joule–Thomson process when being throttled through an orifice; these three gases experience the same effect but only at lower temperatures.[5][6] https://en.wikipedia.org/wiki/Joule–Thomson_effect

Fires from leaks of high pressure hydrogen is a real thing. Sorry to burst your bubble tonight. Have a single malt.

 

[pontiac428]

That is the weird effect I was talking about, forcing through an orifice, film, filter, or diffuse matrix. But if you take a liter of hydrogen and expand it (without letting it escape through microscopic fissures), it will get cooler just like the gas law says.

 

[WobblyHand]

That is the weird effect I was talking about, forcing through an orifice, film, filter, or diffuse matrix. But if you take a liter of hydrogen and expand it (without letting it escape through microscopic fissures), it will get cooler just like the gas law says.

Perhaps there was some misunderstanding or the context was weird. Can't use the Linde expansion process to directly make liquid hydrogen from room temperature, because of this heating effect (in hydrogen, and a few other gases). Mostly the gas law works, except when it doesn't. Probably because the gas in question doesn't behave as an ideal gas when the expansion results in the gas doing work. This chart shows the JT coefficient for a couple of gases.

Nitrogen will liquefy from expansion through an orifice at all temperatures below about 600K. So the Linde process for air liquifaction can start from room temperature. However, hydrogen needs the gas to be chilled to below 200K before the coefficient changes sign. Above 200K, hydrogen heats when escaping through and orifice. This heating can self ignite hydrogen, which burns with a predominantly UV light, ie, not visible. Compressed hydrogen is quite difficult to deal with, because of this. Every leak can be though of expansion through an orifice. You can see from the chart that helium has an even lower temperature before the JT coefficient becomes positive.

At all temps where the coefficient is negative, expansion through an orifice results in heating! Even nitrogen has such a temperature. If nitrogen gas temperature is above 600K and it is allowed to escape through an orifice, nitrogen will heat, not cool.

Physics is fascinating, and can be weird too.

 

[Winegrower]

Really interesting, Wobbly. This is surprising and remarkable, and not covered in any physics class I ever had.
This is important to me as I use Deuterium as a main gas in energy experiments.

This heating can self ignite hydrogen, which burns with a predominantly UV light, ie, not visible.

it’s really UV? Not IR?

 

[WobblyHand]

Really interesting, Wobbly. This is surprising and remarkable, and not covered in any physics class I ever had.


it’s really UV? Not IR?

Puts out a lot of UV. There's IR as well. But UV is commonly used for detection of low level hydrogen leaks. (Which typically auto-ignite.) The UV is the signature of a hydrogen-oxygen fire. IR just tells you something is burning. If you see a lot of UV, its likely a hydrogen fire. Looking for a reference... Found plenty showing propane and hydrogen fires under visible and IR. Need to find something on UV.

 

[thewacokid]

Yeah the only gas we're currently running out of is Helium so good to hear you found other avenues to get it.

 

[WobblyHand]

@Winegrower Found a link on https://zenodo.org/record/1258847/files/article.pdf Title is Visible Emission of Hydrogen Flames
Shows a strong UV signature of hydrogen burning. IR sensors are common place, UV ones not as much.


So there is plenty of IR. But strong UV is also found with burning hydrogen.

 

[great white]

@Winegrower Found a link on https://zenodo.org/record/1258847/files/article.pdf Title is Visible Emission of Hydrogen Flames
Shows a strong UV signature of hydrogen burning. IR sensors are common place, UV ones not as much.
View attachment 421000
View attachment 421001
So there is plenty of IR. But strong UV is also found with burning hydrogen.

Not my feild and certainly not an “expert” on chemistry/physics, but does that chart demonstrate ir/uv emissions from the state change or the chemical reaction from H to oh/h2o?

If creation of molecules is the case, seems any heat energy is more attributable to the creation of the compounds than the expansion of a liquid to gas.

Like I said, I’m no expert on it, just making an uninformed observation….

 

[WobblyHand]

Not my feild and certainly not an “expert” on chemistry/physics, but does that chart demonstrate ir/uv emissions from expansion or the chemical reaction from H to oh/h2o?

If that is the case, seems any heat energy is more attributable to the creation of compound than the expansion of a liquid to gas.

Like I said, I’m no expert on it, just making an uninformed observation….

The article, written at the Combustion Research Facility at Sandia National Labs, states the figure is combustion. The paper is 8 pages, and contains some interesting pictures. It is worth a quick read, in my opinion. The article states the test conditions.

The Joule Thompson effect is entirely different. Leaking compressed room temperature hydrogen heats, depending on the pressure ratio. Very low relative pressures, like found in a laboratory burner, will only slightly heat. Like in a bunsen burner. A 0.5 psi leak is entirely different hazard than say a 1000 psi leak. The low pressure leak will result in flammability or explosion hazard issues as a result of the leak. High pressure leaks tend to self ignite, perhaps after filling the area with hydrogen. The flame is practically invisible in daylight. The open flame could cause other issues in an industrial environment.

Can't profess to be an expert, but my father did work with hydrogen, at the Radiation Laboratory at MIT during and after WWII. I learned a bit about hydrogen safety from him. As a technician in the lab, he fabricated some of the early magnetrons and similar microwave devices. H also worked on the linear accelerator there. He did all sorts of fabrication using all sorts of materials, trying to aid the war effort. Built and used his own hydrogen brazing furnaces at MIT. Later on, after attaining his degrees, he continued to work at MIT.

 

[great white]

The article, written at the Combustion Research Facility at Sandia National Labs, states the figure is combustion. The paper is 8 pages, and contains some interesting pictures. It is worth a quick read, in my opinion. The article states the test conditions.

The Joule Thompson effect is entirely different. Leaking compressed room temperature hydrogen heats, depending on the pressure ratio. Very low relative pressures, like found in a laboratory burner, will only slightly heat. Like in a bunsen burner. A 0.5 psi leak is entirely different hazard than say a 1000 psi leak. The low pressure leak will result in flammability or explosion hazard issues as a result of the leak. High pressure leaks tend to self ignite, perhaps after filling the area with hydrogen. The flame is practically invisible in daylight. The open flame could cause other issues in an industrial environment.

Can't profess to be an expert, but my father did work with hydrogen, at the Radiation Laboratory at MIT during and after WWII. I learned a bit about hydrogen safety from him. As a technician in the lab, he fabricated some of the early magnetrons and similar microwave devices. H also worked on the linear accelerator there. He did all sorts of fabrication using all sorts of materials, trying to aid the war effort. Built and used his own hydrogen brazing furnaces at MIT. Later on, after attaining his degrees, he continued to work at MIT.

Again, just an uniformed observation, but if the test state is combustion (ie: producing oh and h20), it would seem to imply that any thermal and ir/uv emission are a result of the combustion (ie: chemical reaction), not the expansion of the hydrogen.