Why don't we burn Liquid Hydrogen in internal combustion engines similar to rockets, instead of converting to electricity like the Honda FCX?
Posted Dec 17, 2008, 6:55 PM UTC
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Hydrogen embrittlement (or hydrogen grooving) is the process by which various metals, most importantly high-strength steel, become brittle and crack following exposure to hydrogen. Hydrogen cracking can pose an engineering problem especially in the context of a hydrogen economy. However, commercially workable and safe technology exists globally in the hydrogen industry, which produces some 50 million metric tons per year.
Hydrogen embrittlement is also used to describe the formation of zircaloy hydride. This use of the term in this context is common in the nuclear industry..
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One could potentially burn hydrogen gas though. It has a lower flash point than gasoline though.
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[deleted]
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Because of the Hindenburg. Until the safety issues (which are legion) are hammered out so that an undermaintained version of this isn't going to blow up on ignition, it's not going to work.
Oh, there's also the issue that hydrogen requires enormous pressures to be liquid at room temperature. Or, temperatures well below zero (C or F) in order to be liquid at lower pressures. Unless you're planning on building your tank out of diamond and have a multi-million dollar refueling pump, it's not going to work.
Hydrogen does not exist in liquid form at room temperature, because that is well above the critical temperature. (critical temperature is the temperature above which a gas cannot become a liquid).
Instead it is contained in a very highly porous material that can hold a surprising amount of it.
As for hydrogen combustion engines, they are modified petrol or diesel engines and they work. Not as efficient as fuel cell + electric motor though so the latter is probably better.