^^^ More fallacies. Bullets don't ignite things like in the movies.

Hydrogen blimps were failures because of the flammability!!!

I can't believe you are serious now

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Macroscien said..
What is interesting that hydrogen is not that flammable/ explosive as most think.During last wars, the army has been testing blimp filled with hydrogen. How easy is blow up such a thing?
Its appear that ordinary bullets could easily puncture blimp, pass through and nothing happens.Even that hole remains so small that doesn't effect blimp performance much.

Hydrogen takes very little energy to ignite. So much so that it is used as a reference standard for equipment used in hazardous areas. I can't be arsed googling the numbers for you but will go with the experience of spending 10+ years working in a refinery classed as a MHF (major hazardous facility).
Hydrogen can go bang very easily.

I suppose it wouldn't be seabreeze without a pasted link or two...
en.m.wikipedia.org/wiki/Hydrogen_safety
Btw, the plant I worked at had huge amounts of ammonia there and exactly no ammonium nitrate...

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Skid said..

Hydrogen takes very little energy to ignite. So much so that it is used as a reference standard for equipment used in hazardous areas. I can't be arsed googling the numbers for you but will go with the experience of spending 10+ years working in a refinery classed as a MHF (major hazardous facility).
Hydrogen can go bang very easily.

We could go circle all the time.Hydrogen here is proposed as the fuel of future: to power passenger cars, buses, trucks, all by the general public.Millions or billions of people drive cars today.In most cases, hydrogen cars are filled with pure, compressed hydrogen, not ammonia.So we need to decide if hydrogen is too risky to fill airships but can be used by the general public at massive scale. (?)

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Mark _australia said..
^^^ More fallacies. Bullets don't ignite things like in the movies.

Hydrogen blimps were failures because of the flammability!!!

I can't believe you are serious now

Hinderberg, failure due to the flammable skin.Now we know that even when filled with Helium, this aluminum powdered skin will burn easily. You could also claim that Space Shuttle also failed because have been filled with Hydrogen, but it will not be the complete truth.

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Macroscien said..

Hinderberg, failure due to the flammable skin.Now we know that even when filled with Helium, this aluminum powdered skin will burn easily. You could also claim that Space Shuttle also failed because have been filled with Hydrogen, but it will not be the complete truth.

I think there is some merit in what you say, but you need to consider whether the use in airships is different to the use as a fuel in vehicles.

As you say, the Hindenberg disaster was not really the hydrogen that was a problem, but the way it was used. I seem to recall that they would have preferred to use Helium but I think there was a problem because the supplies of this came from the USA.

As with most fuels, it needs an oxidiser. I guess in the case of Hindenberg the gas was able to get exposed to air very quickly when the skin burnt. In a car, is the hydrogen going to vent in some situations and be a controlled release or is it going to be an explosion?

What happens with LPG in a car accident? Does it get vented or does it explode?

Tanks are built to resist the collision, so gas powered cars rarely ignite.
This topic, even 'though it is about a reannouncement from CSIRO of what got announced maybe a year or so ago has piqued my interest.
How do you make a tank for H2? It turns out that it is polyamide on the inside of a carbon fibre container.
And my own question about the whether torque advantage of an electric motor would be affected by using a fuel cell was answered by Professor Google in the affirmative. So you would have a battery to provide large currents for acceleration which would be recharged by the fuel cell.
Then my next thought is that these cars are going to be driverless fairly soon, so why is anybody worried about collisions? They can be lightened up a lot by stripping out airbags and the passenger cage that will not be needed. The problem that I can see is that they will be much more affected by storm winds than steel cars are. Maybe Macroscien can design a flying car to take advantage of their potential lightness.
And if the H2 tank blows up, it is made of plastic, so the shrapnel won't be much of a worry.

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FormulaNova said..

In a car, is the hydrogen going to vent in some situations and be a controlled release or is it going to be an explosion?

Indeed I don't have the slightest idea how hydrogen tanks are built.But let's assume that tank somehow ruptured and whole content at 200-300 bars have been released instantly, mixed obviously with air and ignite.
As you know all air/ fuel mixture may:
a) burn
b) detonate
We know the last when your petrol engine is not properly setup and detonation ( caused by low fuel quality ) will cause our engine to fail quickly.
Every explosive could slowly burn or detonate. Most high explosive (C4?) needs a special procedure/ignition device to detonate.But not Hydrogen/oxygen mix.So which one of the scenario you foresee for exploding from pressure hydrogen tank burning or detonation? I guess we need Myth Busters to take one of those hydrogen tanks and crash in next episode.I remember clearly my firsts experiments 50+ years ago. Igniting 10cm3 hydrogen in a test tube.

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Macroscien said..

FormulaNova said..

In a car, is the hydrogen going to vent in some situations and be a controlled release or is it going to be an explosion?

Indeed I don't have the slightest idea how hydrogen tanks are built.But let's assume that tank somehow ruptured and whole content at 200-300 bars have been released instantly, mixed obviously with air and ignite.
As you know all air/ fuel mixture may:
a) burn
b) detonate
We know the last when your petrol engine is not properly setup and detonation ( caused by low fuel quality ) will cause our engine to fail quickly.
Every explosive could slowly burn or detonate. Most high explosive (C4?) needs a special procedure/ignition device to detonate.But not Hydrogen/oxygen mix.So which one of the scenario you foresee for exploding from pressure hydrogen tank burning or detonation? I guess we need Myth Busters to take one of those hydrogen tanks and crash in next episode.I remember clearly my firsts experiments 50+ years ago. Igniting 10cm3 hydrogen in a test tube.

If it is anything like LPG, the amount of energy required to rupture an LPG tank is enormous and in that case, everything around it is going to be crumpled... so its a fatal crash anyway.

In the more likely scenario, the tank is under physical pressure, so it vents, and potentially the stream of gas is burned. I wouldn't worry too much about these things as our rules here in Australia are going to make sure that these sorts of tanks are relatively safe as we already have standards set.

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Macroscien said.. We have already an almost unlimited supply of cheap natural gas. Cheap and ready to go by tankers.

are you sure??

Last I heard, Queenslanders are crying out for gas to be piped from W.A. as they haven't got enough for themselves.

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sn said..

Macroscien said.. We have already an almost unlimited supply of cheap natural gas. Cheap and ready to go by tankers.

are you sure??

Last I heard, Queenslanders are crying out for gas to be piped from W.A. as they haven't got enough for themselves.

They have got enough, but the crooks in charge have committed the bulk of it to off shore sales. So much that they ran additional pipe lines to tap into Southern States in attempt to resolve the issue. All this did was divert even more to off shore sales.
Now the flogs want to ship it from WA via a pipeline across the middle.
TIFI
.

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FormulaNova said.. >>>>>>>>>>>>>>>>
What happens with LPG in a car accident? Does it get vented or does it explode?

I think I read somewhere a while ago, they'd developed a special tank for hydrogen. It's not hollow, but filled with a sponge like material, that only allows a slow release of the gas. So it's much safer, it can't go up all at once.