5 ms·

The wrong circumstances required to catastrophically release all of that energy in an ICE car is pretty extreme, requiring the fuel to atomize and thoroughly mi

The wrong circumstances required to catastrophically release all of that energy in an ICE car is pretty extreme, requiring the fuel to atomize and thoroughly mix with air. Otherwise you have a fire, not a bomb. Hydrogen by contrast just needs a spark and then it comes to strongly resemble a bomb. If your hydrogen is under pressure, then simple containment failure can be the “spark” required. Plus, gasoline is easy to store, while hydrogen tends to embrittle materials storing it. We shouldn’t short sell just how tricky hydrogen can be.

kbenson 8y ago
Gasoline evaporates under most normal conditions when exposed to air. Fiel soaked rags have been known to spontaneously ignite in garages. I think what you're describing is the decades of safety advances we've had in ICE engine design that allow for safe fuel storage. I'm not trying to say that storing hydrogen is easy, I'm just saying that there's probably a significant amount of things we can do to bring the hazard level down, and there would be a real push for more work on those things if we were routinely using these units at our houses. That is, we would also view the proximity and operation of early model ICE engines to be too hazardous. We've come a long way since then.
- NegativeLatency 8y ago
  I was only aware of oil (not gas) soaked rags spontaneously combusting
  - weaksauce 8y ago
    Yeah, I think that gasoline will just evaporate on a rag. the spontaneous combustion requires something like linseed oil that generates a lot of heat when drying(exothermic) and left alone on a rag.
- pdkl95 8y ago
  > spontaneously ignite Yes, gasoline will burn easily can auto-ignite in common household conditions. I've had the "fun" of running for the garden hose after a roommate made a similar mistake with paper towels soaked with some type of cleaning solution and wiped up engine oil. Fortunately we were able to put out the fire with only minor damage (mostly smoke) to the garage. However, that's only a fire that will burn[1] at a rate roughly proportional to hows quickly it can mix with oxygen (that can be very fast* in some situations). Getting gasoline to act like a bomb and release it's energy at once[2] requires fairly specific conditions. [1] https://en.wikipedia.org/wiki/Deflagration https://en.wikipedia.org/wiki/Deflagration [2] https://en.wikipedia.org/wiki/Detonation https://en.wikipedia.org/wiki/Detonation
pdkl95 8y ago
> If your hydrogen is under pressure, then simple containment failure can be the “spark” required. If the pressure is high enough[1], you don't even need to ignite the hydrogen; pressurized gas storage experiencing catastrophic failure is a bomb. An explosion is rapidly expanding gas. Normally a chemical chain reaction[2] is used to generate that gas, but rupturing high pressure gas storage has very similar effects. Storing a lot of energy in a small space (high energy density) always includes the risk of that energy being released. > We shouldn’t short sell just how tricky hydrogen can be. Working with hydrogen directly is really problematic. However, an easy way to solves most of those problems is stabilizing the hydrogen by attaching it to a chain of carbon atoms. [1] The storage pressure probably is high enough or the design would have used much cheaper low pressure parts. [2] e.g. the common high explosives that store lots of single-bonded nitrogen as a solid and rapidly chain react into triple-bonded N2 gas and a lot of energy
deleted 8y ago
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kbenson 8y ago

Gasoline evaporates under most normal conditions when exposed to air. Fiel soaked rags have been known to spontaneously ignite in garages. I think what you're describing is the decades of safety advances we've had in ICE engine design that allow for safe fuel storage. I'm not trying to say that storing hydrogen is easy, I'm just saying that there's probably a significant amount of things we can do to bring the hazard level down, and there would be a real push for more work on those things if we were routinely using these units at our houses. That is, we would also view the proximity and operation of early model ICE engines to be too hazardous. We've come a long way since then.

NegativeLatency 8y ago
I was only aware of oil (not gas) soaked rags spontaneously combusting
- weaksauce 8y ago
  Yeah, I think that gasoline will just evaporate on a rag. the spontaneous combustion requires something like linseed oil that generates a lot of heat when drying(exothermic) and left alone on a rag.
pdkl95 8y ago
> spontaneously ignite Yes, gasoline will burn easily can auto-ignite in common household conditions. I've had the "fun" of running for the garden hose after a roommate made a similar mistake with paper towels soaked with some type of cleaning solution and wiped up engine oil. Fortunately we were able to put out the fire with only minor damage (mostly smoke) to the garage. However, that's only a fire that will burn[1] at a rate roughly proportional to hows quickly it can mix with oxygen (that can be very fast* in some situations). Getting gasoline to act like a bomb and release it's energy at once[2] requires fairly specific conditions. [1] https://en.wikipedia.org/wiki/Deflagration https://en.wikipedia.org/wiki/Deflagration [2] https://en.wikipedia.org/wiki/Detonation https://en.wikipedia.org/wiki/Detonation

pdkl95 8y ago

> If your hydrogen is under pressure, then simple containment failure can be the “spark” required. If the pressure is high enough[1], you don't even need to ignite the hydrogen; pressurized gas storage experiencing catastrophic failure is a bomb. An explosion is rapidly expanding gas. Normally a chemical chain reaction[2] is used to generate that gas, but rupturing high pressure gas storage has very similar effects. Storing a lot of energy in a small space (high energy density) always includes the risk of that energy being released. > We shouldn’t short sell just how tricky hydrogen can be. Working with hydrogen directly is really problematic. However, an easy way to solves most of those problems is stabilizing the hydrogen by attaching it to a chain of carbon atoms. [1] The storage pressure probably is high enough or the design would have used much cheaper low pressure parts. [2] e.g. the common high explosives that store lots of single-bonded nitrogen as a solid and rapidly chain react into triple-bonded N2 gas and a lot of energy

deleted 8y ago

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