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theloneranger100@aol.com wrote:
But it's dangerous to carry hydrogen in your car.
nope, only if the tank gets ruptured and there is a suitable ignition point nearby, aka in the vent stream, with adequate oxygen mixing in.
You forgot what happen to the space Shuttle?
Is this the one that blew up just above the launch pad? Weren't both travelling at extremely high speeds?
Terryc wrote:
theloneranger100@aol.com wrote:
But it's dangerous to carry hydrogen in your car.
nope, only if the tank gets ruptured and there is a suitable ignition point nearby, aka in the vent stream, with adequate oxygen mixing in.
Plenty of oxygen in the ATMOSPHERE you know ! Duh !
Graham
"Terryc" wrote in message
theloneranger100@aol.com wrote:
But it's dangerous to carry hydrogen in your car.
nope, only if the tank gets ruptured and there is a suitable ignition point nearby, aka in the vent stream, with adequate oxygen mixing in.
You forgot what happen to the space Shuttle?
Is this the one that blew up just above the launch pad? Weren't both travelling at extremely high speeds?
Correct me if I am wrong.
Was it not one of the 'O' rings on one of the solid fuel engines that failed during a under temperature launch (Challenger)? Of course having a nice big hydrogen tank near by didn't help. But my point is, the Challenger craft might still be in use today if it was not pushed to lauch below freezing. Also many other problems turned up not having a thing to do with the fuel itself, just how it was delivered between tank and craft, tank mounts and inspections with ignored results. No matter what though, space travel isn't perfectly safe or childs play. Take care Randy
Randy wrote:
"Terryc" wrote in message theloneranger100@aol.com wrote:
But it's dangerous to carry hydrogen in your car. nope, only if the tank gets ruptured and there is a suitable ignition point nearby, aka in the vent stream, with adequate oxygen mixing in.
You forgot what happen to the space Shuttle? Is this the one that blew up just above the launch pad? Weren't both travelling at extremely high speeds?
Correct me if I am wrong. Was it not one of the 'O' rings on one of the solid fuel engines that failed during a under temperature launch (Challenger)? Of course having a nice big hydrogen tank near by didn't help. But my point is, the Challenger craft might still be in use today if it was not pushed to lauch below freezing. Also many other problems turned up not having a thing to do with the fuel itself, just how it was delivered between tank and craft, tank mounts and inspections with ignored results. No matter what though, space travel isn't perfectly safe or childs play. Take care Randy
Not wrong, but incomplete. The result of the o-ring failure was a jet of
flame out of a test port which played on a liquid fuel tank, which eventually ruptured, terminating the mission. (cf Richard Feinman's account in his autobiography). Despite the spectacular nature of that event as seen from the ground, it occurred over a lot of volume, and the forces involved weren't all that great, I understand it was impact with the ocean that killed the crew.
But the problem with liquefied fuel is not so much its inflammability as the stored energy of compression. It's rather hard to make a fuel explosion with pure hydrogen, the stuff's so damn thin and light you can't get the energy into it to make it mix properly before it wanders off. Think of it more like carrying a few dive cylinders around. They can make quite a bang too.
Tim Jackson One of two, the www.tim-jackson.co.uk one.
On Sat, 29 Mar 2008 10:17:37 +0000, Tim Jackson wrote:
Randy wrote: "Terryc" wrote in message theloneranger100@aol.com wrote:
But it's dangerous to carry hydrogen in your car. nope, only if the tank gets ruptured and there is a suitable ignition point nearby, aka in the vent stream, with adequate oxygen mixing in.
You forgot what happen to the space Shuttle? Is this the one that blew up just above the launch pad? Weren't both travelling at extremely high speeds?
Correct me if I am wrong. Was it not one of the 'O' rings on one of the solid fuel engines that failed during a under temperature launch (Challenger)? Of course having a nice big hydrogen tank near by didn't help. But my point is, the Challenger craft might still be in use today if it was not pushed to lauch below freezing. Also many other problems turned up not having a thing to do with the fuel itself, just how it was delivered between tank and craft, tank mounts and inspections with ignored results. No matter what though, space travel isn't perfectly safe or childs play. Take care Randy
Not wrong, but incomplete. The result of the o-ring failure was a jet of flame out of a test port which played on a liquid fuel tank, which eventually ruptured, terminating the mission. (cf Richard Feinman's account in his autobiography). Despite the spectacular nature of that event as seen from the ground, it occurred over a lot of volume, and the forces involved weren't all that great, I understand it was impact with the ocean that killed the crew.
But the problem with liquefied fuel is not so much its inflammability as the stored energy of compression. It's rather hard to make a fuel explosion with pure hydrogen, the stuff's so damn thin and light you can't get the energy into it to make it mix properly before it wanders off. Think of it more like carrying a few dive cylinders around. They can make quite a bang too.
It's the BANG after the bang that you need to worry about. H2 has a very small ignition energy threshold and a very large explosive mixture range. It can run up to detonation in a corner or confined space.
If you have enough energy available to drive a car 300 mi, you have enough energy to scatter it over a large radius.
But your initial premise is wrong. If H2 is liquefied, it's at low temperature and there's no need to pressurize it. If it's ambient temperature, it's gas, no matter what the pressure. Your comments are correct only for pressurized H2.
Either way, cryogenic or pressurized, it's not convenient, as it's bulky when stored and dangerous when released.
Bill Ward wrote:
On Sat, 29 Mar 2008 10:17:37 +0000, Tim Jackson wrote:
Randy wrote: "Terryc" wrote in message theloneranger100@aol.com wrote:
But it's dangerous to carry hydrogen in your car. nope, only if the tank gets ruptured and there is a suitable ignition point nearby, aka in the vent stream, with adequate oxygen mixing in.
But the problem with liquefied fuel is not so much its inflammability as the stored energy of compression. It's rather hard to make a fuel explosion with pure hydrogen, the stuff's so damn thin and light you can't get the energy into it to make it mix properly before it wanders off. Think of it more like carrying a few dive cylinders around. They can make quite a bang too.
It's the BANG after the bang that you need to worry about. H2 has a very small ignition energy threshold and a very large explosive mixture range. It can run up to detonation in a corner or confined space.
If you have enough energy available to drive a car 300 mi, you have enough energy to scatter it over a large radius.
But your initial premise is wrong. If H2 is liquefied, it's at low temperature and there's no need to pressurize it. If it's ambient temperature, it's gas, no matter what the pressure. Your comments are correct only for pressurized H2.
Either way, cryogenic or pressurized, it's not convenient, as it's bulky when stored and dangerous when released.
Once it escapes the containment or loses refrigeration it doesn't stay liquid for long.
Whether liquefied, compressed, absorbed, compounded or whatever, when it's released it tends to push the air aside rather than mix with it, and most of the volume will be way rich of explosive, and heading skywards fast. Unlike liquid fuel it just can't carry enough momentum to get that mixed with all that thick syrupy air. I don't think you'll see many devastating hydrogen-air explosions from tank ruptures, although you could get a good hot fire from a high pressure leak. The energy's there but its very hard to make it all burn at once.
I'm not condoning the technology, I just don't think that's the problem.
One thing it does do is diffuse very readily. This is probably a bigger threat. If your hydrogen car leaks a little fuel and there is a confined space somewhere, hydrogen will slowly diffuse into it. This raises the internal pressure (you can burst an air filled balloon just by immersing it in hydrogen gas and waiting a while) and it can also make a good explosive mixture, which could result in a nasty bang. Imagine fuel leaking slowly into the boot (trunk) of your car for a day or two, diffusing into your spare tyre which then bursts, striking a spark which detonates the well mixed gases. Would give you quite a kick up the @.
The Zeppelin guys must have known all this stuff. If we'd not run away from hydrogen airships we'd have a lot better handle on the technology.
Tim Jackson One of two, the www.tim-jackson.co.uk one.
Tim Jackson wrote:
... and most of the volume will be way rich of explosive...
Bullshit.
UEL of hydrogen is 76 percent and UFL is 94 percent.
Read the DOT Orange book before you blow yourself off the map.
http://www.tinaja.com/glib/energfun.pdf
-- Many thanks,
Don Lancaster voice phone: (928)428-4073 Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552 rss: http://www.tinaja.com/whtnu.xml email: don@tinaja.com
Please visit my GURU's LAIR web site at http://www.tinaja.com
Don Lancaster wrote:
Tim Jackson wrote:
... and most of the volume will be way rich of explosive...
Bullshit.
UEL of hydrogen is 76 percent and UFL is 94 percent.
Read the DOT Orange book before you blow yourself off the map.
http://www.tinaja.com/glib/energfun.pdf
Nah, I'm older and more responsible nowadays.
I never managed to get a credible bang out of it in my misspent youth, and these days that sort of experiment gets you labelled as a terrorist.
Acetylene was better.
Tim Jackson One of two, the www.tim-jackson.co.uk one.
Eeyore wrote:
nope, only if the tank gets ruptured and there is a suitable ignition point nearby, aka in the vent stream, with adequate oxygen mixing in.
Plenty of oxygen in the ATMOSPHERE you know ! Duh !
Yep, so that hydrogen gas has to; 1; get out of the tank, 2; mix with than oxygen, and 3: be ignited by something.
and only then can it go kaboom.
For any volatile gas tank to explode, the oxygen has to somehow get inside the tank and the mixture then has to explode.
Terryc wrote:
Eeyore wrote:
nope, only if the tank gets ruptured and there is a suitable ignition point nearby, aka in the vent stream, with adequate oxygen mixing in.
Plenty of oxygen in the ATMOSPHERE you know ! Duh !
Yep, so that hydrogen gas has to; 1; get out of the tank, 2; mix with than oxygen, and 3: be ignited by something.
Do 1., then 2. and 3. are given.
For any volatile gas tank to explode, the oxygen has to somehow get inside the tank and the mixture then has to explode.
Then you have never been near a fuel air explosion. Do it and learn some respect. But wait until you have finished your high school chemistry class.
Dan Bloomquist wrote:
Terryc wrote: Eeyore wrote:
nope, only if the tank gets ruptured and there is a suitable ignition point nearby, aka in the vent stream, with adequate oxygen mixing in.
Plenty of oxygen in the ATMOSPHERE you know ! Duh !
Yep, so that hydrogen gas has to; 1; get out of the tank, 2; mix with than oxygen, and 3: be ignited by something.
Do 1., then 2. and 3. are given.
For any volatile gas tank to explode, the oxygen has to somehow get inside the tank and the mixture then has to explode.
Then you have never been near a fuel air explosion. Do it and learn some respect. But wait until you have finished your high school chemistry class.
As a practical matter, there NEVER is any time in the real world when hydrogen is "too rich" to explode.
The least little diffusion and the tiniest static spark will set it on fire, and the expansion will promptly move it down into the very high upper explosive range limit.
I teach hazmat awareness to firemen.
Turning gaseous or liquified hydrogen loose on the general public is fundamentally and ludicrously insane.
Thankfully, it ain't gonna happen.
The ultimate solution is a solar to carbon neutral liquid hydrocarbon conversion that does not in any manner have the staggering exergy losses involved with electrolysis.
Iso octane ain't broke. Neither is heptane.
http://www.tinaja.com/glib/morenrgf.pdf
-- Many thanks,
Don Lancaster voice phone: (928)428-4073 Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552 rss: http://www.tinaja.com/whtnu.xml email: don@tinaja.com
Please visit my GURU's LAIR web site at http://www.tinaja.com
Don Lancaster wrote:
The ultimate solution is a solar to carbon neutral liquid hydrocarbon conversion that does not in any manner have the staggering exergy losses involved with electrolysis.
What do you have in mind?
Dan Bloomquist wrote:
Don Lancaster wrote:
The ultimate solution is a solar to carbon neutral liquid hydrocarbon conversion that does not in any manner have the staggering exergy losses involved with electrolysis.
What do you have in mind?
Metalloradicals, of course.
http://www.tinaja.com/glib/morenrgf.pdf
-- Many thanks,
Don Lancaster voice phone: (928)428-4073 Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552 rss: http://www.tinaja.com/whtnu.xml email: don@tinaja.com
Please visit my GURU's LAIR web site at http://www.tinaja.com
Don Lancaster wrote:
Dan Bloomquist wrote: Don Lancaster wrote:
The ultimate solution is a solar to carbon neutral liquid hydrocarbon conversion that does not in any manner have the staggering exergy losses involved with electrolysis.
What do you have in mind?
Metalloradicals, of course.
So, there is nothing that has practical applications in the works.
On Sun, 30 Mar 2008 10:09:21 -0700, Don Lancaster wrote:
Dan Bloomquist wrote: Terryc wrote: Eeyore wrote:
nope, only if the tank gets ruptured and there is a suitable ignition point nearby, aka in the vent stream, with adequate oxygen mixing in.
Plenty of oxygen in the ATMOSPHERE you know ! Duh !
Yep, so that hydrogen gas has to; 1; get out of the tank, 2; mix with than oxygen, and 3: be ignited by something.
Do 1., then 2. and 3. are given.
For any volatile gas tank to explode, the oxygen has to somehow get inside the tank and the mixture then has to explode.
Then you have never been near a fuel air explosion. Do it and learn some respect. But wait until you have finished your high school chemistry class.
As a practical matter, there NEVER is any time in the real world when hydrogen is "too rich" to explode.
The least little diffusion and the tiniest static spark will set it on fire, and the expansion will promptly move it down into the very high upper explosive range limit.
At high pressure, an H2 leak will often ignite from the static charge generated by the escaping gas. Since the flame is not noticeable in daylight, it can lead to unpleasant surprises.
At the Santa Susanna Rocketdyne facility in the early '60s, when walking around H2 piping, people would wave a broom out in front of themselves, watching for the bristles to start burning. Exciting times.
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