[alancalverd]

I would say the bigger reason was that North Sea gas was there in abundance,

It didn't come on stream until 1967. The changeover on safety grounds began in 1964.

[Bored chemist]

Yes the risk with natural gas is still the same for explosion, though it is higher as the gas tends to accumulate at low points, and is very explosive then,

Really?

[alancalverd]

https://hydrogen.wsu.edu/2017/03/17/so-just-how-dangerous-is-hydrogen-fuel/ is very entertaining and instructive. And the answer is "less than gasoline".

Methane is actually lighter than air but mains gas contains butane and ethane which will pool at the bottom of a vessel. I had the misfortune to watch a small sailing boat disintegrate in about 30 seconds thanks to a faulty butane cooker.

If you think back to your schooldays, or at least anyone old enough to remember proper science lessons with flames and acids, you will recall that hydrogen "burns with a whistling pop", i.e. the flame rate is not supersonic, so although H + O is "highly" explosive, it is not a "high explosive" and doesn't shatter an open container.

An old boss who was posted as a gas company fire watcher during WWII said that when a gasholder was penetrated by an incendiary round (even the Luftwaffe was entitled to some entertainment)  it just produced a quiet  blue flame from the hole. A heavy rubber patch (like a big bicycle puncture repair) extinguished the flame and sealed the orifice.

[Bored chemist]

Methane is actually lighter than air but mains gas contains butane and ethane which will pool at the bottom of a vessel.

In the same way that the denser oxygen settle out into the downstairs bit of your house and you suffocate when you go upstairs.

Why do you keep posting that tosh (and variants on it)?

[paul cotter]

On the matter of explosive gas mixtures a roughly stoichiometric of acetylene and oxygen in a balloon will produce a stunning brisant explosion. IDO NOT RECOMMEND DOING THIS! I have seen it done and it is spectacular. If static from one's hand triggered it you would lose your arms at a minimum and possibly your life.

[Petrochemicals]

https://hydrogen.wsu.edu/2017/03/17/so-just-how-dangerous-is-hydrogen-fuel/ is very entertaining and instructive. And the answer is "less than gasoline".

Methane is actually lighter than air but mains gas contains butane and ethane which will pool at the bottom of a vessel. I had the misfortune to watch a small sailing boat disintegrate in about 30 seconds thanks to a faulty butane cooker.

I cannot believe that any condensed state combust able is less safe than an ariated one in combustive terms, cotton dust, corn dust all utterly lethal. Modern airships use helium for a reason.

[Bored chemist]

I cannot believe that any condensed state combust able is less safe than an ariated one in combustive terms,

Please yourself.
But when I say "Alan is right about this", you should probably pay attention.

[alancalverd]

In the same way that the denser oxygen settle out into the downstairs bit of your house and you suffocate when you go upstairs.

The oxygen content of air does indeed decrease with altitude, but less rapidly than the carbon dioxide content, and not a lot anyway because the atmosphere is in continual turbulence. But safety warnings about dense combustible gases and suffocants in enclosed spaces should not be ignored. Radon tends to pool in basements from which it can be extracted, and for arcane reasons apparently known only to the contractors though obvious to most people, the suction heads are at low level.

[Bored chemist]

not a lot anyway

How much?
Show us some numbers.
For example, say you have a gas cylinder1 metre high
 containing equal numbers of molecules of butane and methane gas near room temperature.
What are the relative concentrations of the 2 molecules at the top and the bottom of the cylinder?

For extra credit, tell us what practical difference that "enrichment" makes.

[Bored chemist]

Radon tends to pool in basements from which it can be extracted,

No, it doesn't.

, and for arcane reasons apparently known only to the contractors though obvious to most people, the suction heads are at low level.

The reason is, indeed obvious.
Radon is formed by rocks, so it comes in through the ground.
That's why radon levels are typically highest in cellars and basements.
IT IS NOT BECAUSE  THE GAS FALLS INTO THE CELLAR AND GETS STUCK.

[Bored chemist]

But safety warnings about dense combustible gases and suffocants in enclosed spaces should not be ignored.

There is a world of difference between the fact that, if you get a butane leak in the cellar, it will tend to stay in the cellar for a while and the idea that gases "unmix".

[alancalverd]

So all that money spent on gas centrifuges was wasted, and you can't separate the hexafluorides of uranium isotopes after all.

[Bored chemist]

So all that money spent on gas centrifuges was wasted, and you can't separate the hexafluorides of uranium isotopes after all.

In the very real sense that a million g is the same as 1 g.
And you still need a stack of them to get a useful separation.
https://en.wikipedia.org/wiki/Gas_centrifuge#/media/File:Gas_centrifuge_cascade.jpg

So, let's see your answer to this

For example, say you have a gas cylinder1 metre high
 containing equal numbers of molecules of butane and methane gas near room temperature.
What are the relative concentrations of the 2 molecules at the top and the bottom of the cylinder?

[alancalverd]

Not very different, but different.

You will note that although hydrogen is produced, used and discharged in enormous quantities in various industries, there is very little at ground level in the atmosphere. And the world is running out of helium even though it doesn't form stable compounds. Obviously, the fairies take it away to make their gossamer wings, like they stole the water from Mars and left the CO2 behind.

[Bored chemist]

So, let's see your answer to this




Quote from: Bored chemist on Yesterday at 18:01:38
For example, say you have a gas cylinder1 metre high
 containing equal numbers of molecules of butane and methane gas near room temperature.
What are the relative concentrations of the 2 molecules at the top and the bottom of the cylin

[Bored chemist]

The really odd bit is that you even know why you are plainly wrong.

not a lot anyway because the atmosphere is in continual turbulence.

Yes, the weather shuffles the air around.
But it's pretty rare for windspeeds to exceed 30 m/s anywhere near ground level.
But the speeds of the molecules in the air I'm breathing are about 300m/s.
So you know why they get mixed.
Yet you pretend that they settle out.
So, go on- tell us how well gravity separates them.

[alancalverd]

Not very well at all.

[Bored chemist]

So, have you got to grips with teh fact that this

Methane is actually lighter than air but mains gas contains butane and ethane which will pool at the bottom

is nonsense?

[Petrochemicals]

Oxygen and hydrogen nitrogen are reasonably close in density, where as argon is considerabley heavier, at 1 percent of the atmosphere the surface of the earth should have a layer 250m deep on the surface.

[alancalverd]

Oxygen and hydrogen are reasonably close in density,

Which is why hydrogen balloons don't fly.