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Reconsider Hydrogen

Mix Hydrogen with inert element as a cheap lifting gas
  [vote for,

Helium is expensive and non-renewable. Hydrogen is cheap and plentiful, but it's flammable. The lower explosion limit of Hydrogen in air is 4%, so as a first pass on solving the problem of finding a lifting gas that's both cheap and safe, Hydrogen could be diluted in air. However, since Nitrogen is also cheap and is also non- flammable (practically speaking, since nitrous oxides require a high activation energy), a higher concentration of Hydrogen could be mixed with Nitrogen to produce an even lighter gas that is also cheap and non-flammable.
kevinthenerd, Mar 10 2017


       I'm anticipating somebody with maths to come along and poke holes in this balloon ...
normzone, Mar 10 2017

       Well, pure hydrogen won't burn by itself, so it's only a problem when it mixes with air. And if it's going to meet air, then any concentration of hydrogen that starts out at 4% or higher will burn.   

       Plus, the more you dilute the hydrogen, the more volume you need, which means more surface, which means more opportunities for the surface to be punctured.   

       It's six of one and roundabouts of the other. Hydrogen airships are, in fact, about as safe as helium ones. If a hydrogen airship springs a leak, and if it somehow finds a source of ignition, you generally get a big flame that starts some distance away from the envelope and doesn't do any immediate harm. It's only public perception that prevents widespread use of hydrogen as a lifting gas.
MaxwellBuchanan, Mar 10 2017

       Pity there isn't an emergency drone to act as a bunsen jet and direction burn in a needed direction.
wjt, Mar 10 2017

       Well, you could always mix it with Helium. Based on your research, adding 4% would be completely safe and marginally reduce the cost. Or you could add more. Assume you verify [Max]'s assertions with safety testing, you could sell a mix with 99% H and 1% He. You could say that adding the He reduces the flammability (marginally), and that the system is safe.
scad mientist, Mar 10 2017

       But helium is a plentiful and cheap, as a product of nuclear fusion. I'm sure we've invented *that* several times.
pertinax, Mar 10 2017

       Nuclear fusion is indeed Baked and WKTE.
8th of 7, Mar 11 2017

       Well, you could mix Helium with SF6, but it kinda defeats the purpose.
Ling, Mar 11 2017

       Neon is underrated as a lifting gas. It's about half the density of air.
nineteenthly, Mar 11 2017

       //Well, pure hydrogen won't burn by itself, so it's only a problem when it mixes with air. And if it's going to meet air, then any concentration of hydrogen that starts out at 4% or higher will burn.//   

       It sounds like its better to getting the burning over with and just use 'burnt hydrogen' as the lifting gas.
bigsleep, Mar 11 2017

       That would be a steam balloon, which is WKTE - water (as a gas) has a little more than half the density of air.
MaxwellBuchanan, Mar 11 2017

       //Reconsider Hydrogen Have you considered Consider Phlebas?
not_morrison_rm, Mar 11 2017

       //That would be a steam balloon//   

       Steam would melt stuff. Would probably be better to let the steam gas cool down and use that, but the half the density of air sounds good.
bigsleep, Mar 11 2017

       Helium is baked and WKTE. Hydrogen is WKTE but you can't bake it safely.
pashute, Mar 15 2017

       Actually, you can - in the absence of oxygen ...
8th of 7, Mar 15 2017

       Great idea to [Reconsider Hydrogen], kevinthenerd, as the He depletion on Earth will be a catastrophe.   

       At first, the German WWI war-zeppelins, using pure H² as the lifting gas, were near impossible to knock down during their siege of London, until later. They usually were able to limp home, be repaired, re-filled, and then return. (PBS documentary.)   

       Arthur C. Clark - (RIP) - mentioned that 80% He / 20% H² was the maximum [cheap] H² you could add to He and still be non-combustible. So a little bit of He savings there.   

       There is ~5 billion years of 1mm thick solid He on the surface of the moon [from cosmic rays] to be harvested. It is even lighter than the He on Earth, because they only have 1 neutron + 2 protons from Solar nuclear fusion, compared to the Terrestrial alpha particle He on Earth which is one nucleon heavier- (2 neutrons + 2 protons) - from nuclear fission.   

       I've been thinking about how to harvest lunar He for decades, but first we need to start extracting [more] He from natural gas here on Earth. Some wells (Texas / Oklahoma, USA) are as high as 6% He...
Speed Razor, Mar 17 2017

       If we're going to start harvesting He3 from the moon, using it for lifting gas is about the most absurdly inefficient waste of resources that I can conveniently think of. It's like mining and refining Iridium, then using it for fishing sinkers or ship's ballast. There's any number of nuclear fusion research institutes who would be happy to take it off your hands for maybe 1000 or even 1000000 times what you could sell it for as a lifting gas.   

       // But helium is a plentiful and cheap, as a product of nuclear fusion// - Not really, the quantities aren't there yet and won't be for many a year to come. A gigawatt fusion power station would be producing litres per day of helium, not belching it out as an exhaust gas.
Custardguts, Apr 04 2017

       Your primary's absolutely packed with the stuff, why not use that ?
8th of 7, Apr 05 2017


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