Google Groups no longer supports new Usenet posts or subscriptions. Historical content remains viewable.
Dismiss

"Low-carbon hydrogen"

211 views
Skip to first unread message

occam

unread,
Nov 22, 2022, 2:27:45 AM11/22/22
to
"Industrial gases company Air Liquide (AIRP.PA) and TotalEnergies
(TTEF.PA) plans to produce low-carbon hydrogen at the Grandpuits site in
France, it said on Tuesday."

The above sentence made me scramble to my periodic table, to see if the
French had made a breakthrough in chemistry.

I never liked the wet sciences, and I was relieved to find that the
little chemistry I knew was still valid.

Source:
https://www.reuters.com/business/sustainable-business/air-liquide-totalenergies-produce-low-carbon-hydrogen-france-2022-11-22/

Hibou

unread,
Nov 22, 2022, 3:37:34 AM11/22/22
to
This article - more than a year older - on TotalEnergies' and Air
Liquide's web sites contains the same wording:

<https://totalenergies.com/fr/medias/actualite/communiques-presse/totalenergies-air-liquide-sassocient-developper-production>

Reuters seem to be a bit behind.

'Low-carbon hydrogen' does seem strange - as does 'decarbonise', since
it evokes top-overhauling a car.

occam

unread,
Nov 22, 2022, 5:18:11 AM11/22/22
to
On 22/11/2022 09:37, Hibou wrote:
> Le 22/11/2022 à 07:27, occam a écrit :
>>
>> "Industrial gases company Air Liquide (AIRP.PA) and TotalEnergies
>> (TTEF.PA) plans to produce low-carbon hydrogen at the Grandpuits site in
>> France, it said on Tuesday."
>>
>> The above sentence made me scramble to my periodic table, to see if the
>> French had made a breakthrough in chemistry.
>>
>> I never liked the wet sciences, and I was relieved to find that the
>> little chemistry I knew was still valid.
>>
>> Source:
>> https://www.reuters.com/business/sustainable-business/air-liquide-totalenergies-produce-low-carbon-hydrogen-france-2022-11-22/
>
> This article - more than a year older - on TotalEnergies' and Air
> Liquide's web sites contains the same wording:
>
> <https://totalenergies.com/fr/medias/actualite/communiques-presse/totalenergies-air-liquide-sassocient-developper-production>
>
> Reuters seem to be a bit behind.

Either that, or Air Liquide has re-released its initial announcement (on
22 Nov, from Paris), as it is a lot behind its planned production.

Peter Moylan

unread,
Nov 22, 2022, 5:35:07 AM11/22/22
to
The
>
>
business world has its own terminology, which does not necessarily
agree with that of people with a scientific education. I can almost
guarantee that the chemists and engineers in those two companies speak a
different language (among themselves) from that used by the management
people.

The same stuff is known in Australia as "green hydrogen". It was
colourless the last time I took a chemistry course, but the world has
moved on. Perhaps the removal of carbon from a hydrogen atom changes the
colour.

Side comment: the extraction of hydrogen from water is hideously
expensive in terms of electrical energy, and it also involves throwing
away the biggest part (oxygen) of the water molecules [1]. But perhaps
that does not matter if the electrical energy comes from sunlight that
would otherwise be wasted.

I have a feeling that some researchers are looking at a different
approach that is less wasteful. Something to do with catalysts? But I
have not been following that news, so I might have it wrong.

[1] A water molecule is basically an oxygen atom with a couple of
protons tacked onto the edge. Sort of like a neon atom with two of the
protons expelled to the outer suburbs to compensate for a neutron deficit.

--
Peter Moylan Newcastle, NSW http://www.pmoylan.org

J. J. Lodder

unread,
Nov 22, 2022, 7:01:56 AM11/22/22
to
occam <oc...@nowhere.nix> wrote:

> "Industrial gases company Air Liquide (AIRP.PA) and TotalEnergies
> (TTEF.PA) plans to produce low-carbon hydrogen at the Grandpuits site in
> France, it said on Tuesday."
>
> The above sentence made me scramble to my periodic table, to see if the
> French had made a breakthrough in chemistry.

Yes, and why not? Hydrogen is still made from methane,
which releases vast quantities of CO2 into the atmosphere.
It is the dominant method, at present.

Any hydrogen that is produced by a process that liberates less carbon
can be called 'low-carbon hydrogen' wih good reason.

Jan

J. J. Lodder

unread,
Nov 22, 2022, 7:01:57 AM11/22/22
to
Peter Moylan <pe...@pmoylan.org.invalid> wrote:

> On 22/11/22 18:27, occam wrote:
>
> > "Industrial gases company Air Liquide (AIRP.PA) and TotalEnergies
> > (TTEF.PA) plans to produce low-carbon hydrogen at the Grandpuits
> > site in France, it said on Tuesday."
> >
> > The above sentence made me scramble to my periodic table, to see if
> > the French had made a breakthrough in chemistry.
> >
> > I never liked the wet sciences, and I was relieved to find that the
> > little chemistry I knew was still valid.
> >
> > Source:
> > https://www.reuters.com/business/sustainable-business/air-liquide-totalenerg
ies-produce-low-carbon-hydrogen-france-2022-11-22/
>
> The
> >
> >
> business world has its own terminology, which does not necessarily
> agree with that of people with a scientific education. I can almost
> guarantee that the chemists and engineers in those two companies speak a
> different language (among themselves) from that used by the management
> people.
>
> The same stuff is known in Australia as "green hydrogen". It was
> colourless the last time I took a chemistry course, but the world has
> moved on. Perhaps the removal of carbon from a hydrogen atom changes the
> colour.
>
> Side comment: the extraction of hydrogen from water is hideously
> expensive in terms of electrical energy, and it also involves throwing
> away the biggest part (oxygen) of the water molecules.

Huh? What do you think that Air Liquide sells, apart from LN2 ?
It has all kinds of practical uses,
from medical applications to steel production.
It is easily transported with truck-trailer combinations.

> But perhaps that does not matter if the electrical energy comes from
> sunlight that would otherwise be wasted.

For what it is worth:
most 'green hydrogen' in the EU will be produced with electricity
from huge windmill parks being built in the North Sea,

Jan

Quinn C

unread,
Nov 22, 2022, 8:24:44 AM11/22/22
to
* Peter Moylan:

> On 22/11/22 18:27, occam wrote:
>
>> "Industrial gases company Air Liquide (AIRP.PA) and TotalEnergies
>> (TTEF.PA) plans to produce low-carbon hydrogen at the Grandpuits
>> site in France, it said on Tuesday."
>>
>> The above sentence made me scramble to my periodic table, to see if
>> the French had made a breakthrough in chemistry.
>>
>> I never liked the wet sciences, and I was relieved to find that the
>> little chemistry I knew was still valid.
>>
>> Source:
>> https://www.reuters.com/business/sustainable-business/air-liquide-totalenergies-produce-low-carbon-hydrogen-france-2022-11-22/
>
> The
>>
>>
> business world has its own terminology, which does not necessarily
> agree with that of people with a scientific education. I can almost
> guarantee that the chemists and engineers in those two companies speak a
> different language (among themselves) from that used by the management
> people.
>
> The same stuff is known in Australia as "green hydrogen". It was
> colourless the last time I took a chemistry course, but the world has
> moved on. Perhaps the removal of carbon from a hydrogen atom changes the
> colour.

There are far more colors available. This site lists green, blue, grey,
black, brown, pink, turquoise, yellow and white hydrogen

<https://www.nationalgrid.com/stories/energy-explained/hydrogen-colour-spectrum>

--
Hope and the odds make poor bedfellows.
-- Captain Picard, Picard S01E08

occam

unread,
Nov 27, 2022, 11:38:36 AM11/27/22
to
Like Oxygen bars in New York?

> from medical applications to steel production.
> It is easily transported with truck-trailer combinations.
>
>> But perhaps that does not matter if the electrical energy comes from
>> sunlight that would otherwise be wasted.
>
> For what it is worth:
> most 'green hydrogen' in the EU will be produced with electricity
> from huge windmill parks being built in the North Sea,

Are you saying green hydrogen will be used as a substitute for batteries
- for storing energy? What a waste! Hydrogen, apart from being a very
dangerous substance to handle, is also a very expensive ('inefficient')
storage device.


>
> Jan
>

Bertel Lund Hansen

unread,
Nov 27, 2022, 12:00:59 PM11/27/22
to
Den 27.11.2022 kl. 17.38 skrev occam:

> Are you saying green hydrogen will be used as a substitute for batteries
> - for storing energy? What a waste! Hydrogen, apart from being a very
> dangerous substance to handle, is also a very expensive ('inefficient')
> storage device.

The containers in cars have a pressure of 700 bars.

I don't either see much of a future in hydrogen, but I can see it being
useful in planes where batteries would make it impossible to lift off.

On the other hand I don't really see it as realistic to replace all fuel
cars with electric cars. There's not enough resources (rare metals) on
our whole planet to make it possible.

So maybe oldfashioned fuel cars with green fuel produced with
electricity is the future? Though the process is expensive energywise.

--
Bertel

Kerr-Mudd, John

unread,
Nov 28, 2022, 7:58:52 AM11/28/22
to
On Sun, 27 Nov 2022 17:38:31 +0100
occam <oc...@nowhere.nix> wrote:

> On 22/11/2022 13:01, J. J. Lodder wrote:
[]
> >
> > For what it is worth:
> > most 'green hydrogen' in the EU will be produced with electricity
> > from huge windmill parks being built in the North Sea,
>
> Are you saying green hydrogen will be used as a substitute for batteries
> - for storing energy? What a waste! Hydrogen, apart from being a very
> dangerous substance to handle, is also a very expensive ('inefficient')
> storage device.
>

Quite. Hydrogen is being pushed by the Vested Interests;, possibly as
greenwashing.


--
Bah, and indeed Humbug.

Richard Heathfield

unread,
Nov 28, 2022, 8:06:48 AM11/28/22
to
Has anyone told them it has a tendency to go bang?

--
Richard Heathfield
Email: rjh at cpax dot org dot uk
"Usenet is a strange place" - dmr 29 July 1999
Sig line 4 vacant - apply within

Peter Moylan

unread,
Nov 28, 2022, 8:11:00 AM11/28/22
to
On 29/11/22 00:06, Richard Heathfield wrote:
> On 28/11/2022 12:45 pm, Kerr-Mudd, John wrote:
>> On Sun, 27 Nov 2022 17:38:31 +0100
>> occam <oc...@nowhere.nix> wrote:
>>
>>> On 22/11/2022 13:01, J. J. Lodder wrote:
>> []
>>>> For what it is worth:
>>>> most 'green hydrogen' in the EU will be produced with electricity
>>>> from huge windmill parks being built in the North Sea,
>>>
>>> Are you saying green hydrogen will be used as a substitute for batteries
>>> - for storing energy? What a waste! Hydrogen, apart from being a very
>>> dangerous substance to handle, is also a very expensive ('inefficient')
>>> storage device.
>>
>> Quite. Hydrogen is being pushed by the Vested Interests;, possibly as
>> greenwashing.
>
> Has anyone told them it has a tendency to go bang?

Only if exposed to an oxygen atmosphere. It's perfectly safe on Jupiter.

Athel Cornish-Bowden

unread,
Nov 28, 2022, 8:21:34 AM11/28/22
to
On 2022-11-28 13:06:43 +0000, Richard Heathfield said:

> On 28/11/2022 12:45 pm, Kerr-Mudd, John wrote:
>> On Sun, 27 Nov 2022 17:38:31 +0100
>> occam <oc...@nowhere.nix> wrote:
>>
>>> On 22/11/2022 13:01, J. J. Lodder wrote:
>> []
>>>>
>>>> For what it is worth:
>>>> most 'green hydrogen' in the EU will be produced with electricity
>>>> from huge windmill parks being built in the North Sea,
>>>
>>> Are you saying green hydrogen will be used as a substitute for batteries
>>> - for storing energy? What a waste! Hydrogen, apart from being a very
>>> dangerous substance to handle, is also a very expensive ('inefficient')
>>> storage device.
>>>
>>
>> Quite. Hydrogen is being pushed by the Vested Interests;, possibly as
>> greenwashing.
>
> Has anyone told them it has a tendency to go bang?

Yes, but so has petrol.


--
Athel -- French and British, living in Marseilles for 36+ years; mainly
in England until 1987.

Ken Blake

unread,
Nov 28, 2022, 10:44:00 AM11/28/22
to
By Jove, I think you're right!

Paul Wolff

unread,
Nov 28, 2022, 7:31:17 PM11/28/22
to
On Mon, 28 Nov 2022, at 13:06:43, Richard Heathfield posted:
>On 28/11/2022 12:45 pm, Kerr-Mudd, John wrote:
>> On Sun, 27 Nov 2022 17:38:31 +0100
>> occam <oc...@nowhere.nix> wrote:
>>
>>> On 22/11/2022 13:01, J. J. Lodder wrote:
>> []
>>>>
>>>> For what it is worth:
>>>> most 'green hydrogen' in the EU will be produced with electricity
>>>> from huge windmill parks being built in the North Sea,
>>>
>>> Are you saying green hydrogen will be used as a substitute for batteries
>>> - for storing energy? What a waste! Hydrogen, apart from being a very
>>> dangerous substance to handle, is also a very expensive ('inefficient')
>>> storage device.
>>>
>> Quite. Hydrogen is being pushed by the Vested Interests;, possibly
>>as
>> greenwashing.
>
>Has anyone told them it has a tendency to go bang?
>
Drat! Do you mean our hydrogen bomb isn't a secret any more?
--
Paul W

Mack A. Damia

unread,
Nov 28, 2022, 7:47:57 PM11/28/22
to
Check out the 2018 film, "The Command" with Colin Firth and Max von
Sydow (not the principals). About a state-of-the-art Russian nuclear
submarine. Based on the true story of the 2000 Kursk submarine
disaster. One of the torpedoes has a hydrogen peroxide leak and
explodes, and then the others explode forcing the surving crew to the
aft-most compartment that is rapidly taking on water.

Russians will not let other countries help because of the secret
technology on the sub. Firth plays a Royal Navy commodore, von Sydow a
Russian admiral.

Good suspense.


Richard Heathfield

unread,
Nov 29, 2022, 12:49:05 AM11/29/22
to
Ours, possibly not. But don't worry; mine still is.

Bertel Lund Hansen

unread,
Nov 29, 2022, 2:46:02 AM11/29/22
to
Den 28.11.2022 kl. 14.06 skrev Richard Heathfield:

>> Quite. Hydrogen is being pushed by the Vested Interests;, possibly as
>> greenwashing.
>
> Has anyone told them it has a tendency to go bang?

If you fill a baloon with hydrogen, puncture it and light the gas, it
burns. It doesn't explode.

If you fill a 1 liter pee bag with 1/3 hydrogen and 2/3 oxygen and then
just pop it with a burning match (a glow is enough), you get a bang that
will wake up any sleeping pupil in the class room.

--
Bertel

Bertel Lund Hansen

unread,
Nov 29, 2022, 2:49:01 AM11/29/22
to
Den 29.11.2022 kl. 01.47 skrev Mack A. Damia:

> Check out the 2018 film, "The Command" with Colin Firth and Max von
> Sydow (not the principals). About a state-of-the-art Russian nuclear
> submarine. Based on the true story of the 2000 Kursk submarine
> disaster. One of the torpedoes has a hydrogen peroxide leak and
> explodes,

Yes, because the hydrogen gets mixed with oxygene first. The first
explosion triggers the following ones.

Tanks with gasoline that leaked, would have behaved in the same manner.
A hydrogen explosion may be stronger than a gasoline one, but I don't
think that the crew would have cared.

--
Bertel

J. J. Lodder

unread,
Nov 29, 2022, 4:57:38 AM11/29/22
to
Part of it can be used directly in industrial processes,
such as making steel and fertiliser.
(which use coal and natural gas at present)
More generally hydrogen can be used to supply high temperature
industrial proces heat.

Apart from that, you should consider that the kWh price
regularly goes negative when there is a lot of wind.
This will only get more so in the near future.
When you get paid for absorbing surplus power
your hydrogen cannot be too expensive,

Jan


J. J. Lodder

unread,
Nov 29, 2022, 4:57:39 AM11/29/22
to
Sure, highest of technology, straight from the U-Boot.
Make that Russian state of the art.

> Russians will not let other countries help because of the secret
> technology on the sub. Firth plays a Royal Navy commodore, von Sydow a
> Russian admiral.
>
> Good suspense.

And then (and not for Hollywood) the Russians call in the Dutch
to salvage the wreck and get the bodies out,

Jan

J. J. Lodder

unread,
Nov 29, 2022, 4:57:39 AM11/29/22
to
Richard Heathfield <r...@cpax.org.uk> wrote:

> On 28/11/2022 12:45 pm, Kerr-Mudd, John wrote:
> > On Sun, 27 Nov 2022 17:38:31 +0100
> > occam <oc...@nowhere.nix> wrote:
> >
> >> On 22/11/2022 13:01, J. J. Lodder wrote:
> > []
> >>>
> >>> For what it is worth:
> >>> most 'green hydrogen' in the EU will be produced with electricity
> >>> from huge windmill parks being built in the North Sea,
> >>
> >> Are you saying green hydrogen will be used as a substitute for batteries
> >> - for storing energy? What a waste! Hydrogen, apart from being a very
> >> dangerous substance to handle, is also a very expensive ('inefficient')
> >> storage device.
> >>
> >
> > Quite. Hydrogen is being pushed by the Vested Interests;, possibly as
> > greenwashing.
>
> Has anyone told them it has a tendency to go bang?

Like the Hindenburg at New York?
(for the biggest example, so far)

It burned fiercely, but did not explode.
Fatalities were about 30% of those on board.
An explosion would certainy have killed all.

Jan

occam

unread,
Nov 29, 2022, 6:18:18 AM11/29/22
to
Putting a match to a 'pee bag'(?)! What kind of schools did you teach
in, Bertel? And what are pee bags used for?

Bertel Lund Hansen

unread,
Nov 29, 2022, 11:01:26 AM11/29/22
to
Den 29.11.2022 kl. 12.18 skrev occam:

>> If you fill a 1 liter pee bag with 1/3 hydrogen and 2/3 oxygen and then
>> just pop it with a burning match (a glow is enough), you get a bang that
>> will wake up any sleeping pupil in the class room.
>>
>
> Putting a match to a 'pee bag'(?)! What kind of schools did you teach
> in, Bertel?

An ordinary school. Grades from 0 (Kindergarten-class) to 10.

> And what are pee bags used for?

Pee. We got them for physics and chemistry because they are well suited
for being blown up with gas or filled with liquid. There are several
experiments where they are useful.

Here's a picture:
https://seniorshop.dk/media/catalog/product/cache/4d8daa82b8e52698d2aba7879be1ccec/3/5/350305-1.jpg

--
Bertel

Mack A. Damia

unread,
Nov 29, 2022, 11:03:43 AM11/29/22
to
An "oxygen canister" is dropped into the water accidently and results
in a flash fire/explosion. It depletes the oxygen in the compartment;
thus, sealing their fate.

Same chemical reaction?


Bertel Lund Hansen

unread,
Nov 29, 2022, 11:18:20 AM11/29/22
to
Den 29.11.2022 kl. 08.48 skrev Bertel Lund Hansen:

> Yes, because the hydrogen gets mixed with oxygene first. The first
> explosion triggers the following ones.

Sorry. I got misled by the name "hydrogen peroxid". It's oxygen that is
released, and free oxygen will connect with any substance that can burn.
The slightest spark wil trigger a violent fire or an explosion. It's
more reactive because it is single oxygen atoms that are released, not
the usual O2.

--
Bertel

Mack A. Damia

unread,
Nov 29, 2022, 11:53:30 AM11/29/22
to
On Tue, 29 Nov 2022 17:18:16 +0100, Bertel Lund Hansen
<gade...@lundhansen.dk> wrote:

>Den 29.11.2022 kl. 08.48 skrev Bertel Lund Hansen:
>
>> Yes, because the hydrogen gets mixed with oxygene first. The first
>> explosion triggers the following ones.
>
>Sorry. I got misled by the name "hydrogen peroxide". It's oxygen that is
>released, and free oxygen will connect with any substance that can burn.
>The slightest spark wil trigger a violent fire or an explosion. It's
>more reactive because it is single oxygen atoms that are released, not
>the usual O2.

Much of the film must have been fictionalized. I am unaware that the
sub was in touch with the outside world after the explosion, so how
did anybody know what was happening?

Peter T. Daniels

unread,
Nov 29, 2022, 1:07:49 PM11/29/22
to
On Tuesday, November 29, 2022 at 4:57:39 AM UTC-5, J. J. Lodder wrote:
> Richard Heathfield <r...@cpax.org.uk> wrote:
> > On 28/11/2022 12:45 pm, Kerr-Mudd, John wrote:

> > > Quite. Hydrogen is being pushed by the Vested Interests;, possibly as
> > > greenwashing.
> > Has anyone told them it has a tendency to go bang?
>
> Like the Hindenburg at New York?

Lakehurst, New Jersey.

> (for the biggest example, so far)

It had made several successful crossings.

> It burned fiercely, but did not explode.
> Fatalities were about 30% of those on board.

Said to be because they were urged to jump. The
survivors were the ones who didn't leave the cabin.

> An explosion would certainy have killed all.

Recently two documentaries attempting to discover the cause
of the fire have been shown on PBS. There's no definitive answer.

Sam Plusnet

unread,
Nov 29, 2022, 2:12:50 PM11/29/22
to
Won't grease and oil spontaneously combust in a rich O2 atmosphere?
Torpedoes are usually well greased, to unsure they exit their tube
without any hang-ups.

--
Sam Plusnet

Sam Plusnet

unread,
Nov 29, 2022, 2:17:34 PM11/29/22
to
Use the surplus energy to produce hydrogen, and then use the hydrogen to
power your ferry.

https://www.heraldscotland.com/business_hq/18789377.scotland-trial-worlds-first-hydrogen-powered-ferry-orkney/

(I think the url supplies the basic information, without having to click
on the link.)

--
Sam Plusnet

Tony Cooper

unread,
Nov 29, 2022, 2:47:47 PM11/29/22
to
If greasing the chamber makes the exit ability unsure, it would seem
to make the practice self-defeating for the launcher.

OK...I know you meant "ensure" or "insure", but taking a swing at
low-hanging fruit is allowed here.


--

Tony Cooper - Orlando Florida

I read and post to this group as a form of entertainment.

Bertel Lund Hansen

unread,
Nov 29, 2022, 3:31:17 PM11/29/22
to
Den 29.11.2022 kl. 17.53 skrev Mack A. Damia:

> Much of the film must have been fictionalized. I am unaware that the
> sub was in touch with the outside world after the explosion, so how
> did anybody know what was happening?

It must be educated guesses. If I remember correctly it was known that
there was an explosion, and I remember for certain that some ships heard
knocking sounds from the sub after the explosion.

--
Bertel

Bertel Lund Hansen

unread,
Nov 29, 2022, 3:34:31 PM11/29/22
to
Den 29.11.2022 kl. 20.12 skrev Sam Plusnet:

> Won't grease and oil spontaneously combust in a rich O2 atmosphere?

Yes. It is prohibited (or just known to be too risky?) to grease the
"screw path" (?) of an oxygen container precisely for that reason
however much it squeeks.

--
Bertel

J. J. Lodder

unread,
Nov 29, 2022, 4:51:48 PM11/29/22
to
Bertel Lund Hansen <gade...@lundhansen.dk> wrote:

There is nothing to mislead. Hydrogen peroxide at high concentration
can be used as torpedo (or rocket) propellant.
It decomposes into steam and oxygen when passed over a catalyst.
Nothing new or high tech here: German U-Boote already used it in WWII.

Kursk was destroyed by a torpedo propellant leak,
caused by shoddy workmanship,

Jan

J. J. Lodder

unread,
Nov 29, 2022, 4:51:48 PM11/29/22
to
Thanks.
I passed it on to someone with a professional interest in things like
that.
Scotland is no doubt one of those places
where negative electricity prices should be common.

Jan

Peter Moylan

unread,
Nov 29, 2022, 7:21:58 PM11/29/22
to
Isaac Asimov once wrote a murder mystery where that was an important
point that had to be explained.

Peter Moylan

unread,
Nov 29, 2022, 7:27:25 PM11/29/22
to
My school didn't rise to that level of sophistication. We did have
fart-lighting in the boys' toilet.

In a much later year, I once had to dive through a classroom window when
the hydrogen sulphide went from "intense stink" to odourless. I never
discovered why others in the room were unaffected.

Sam Plusnet

unread,
Nov 29, 2022, 8:12:34 PM11/29/22
to
I'm going to blame this 'ere keyboard. It seems to argue with almost
every worm I posit.


--
Sam Plusnet

Richard Heathfield

unread,
Nov 29, 2022, 8:51:24 PM11/29/22
to
s/keyboard/leopard

https://xkcd.com/1031/

Rich Ulrich

unread,
Nov 30, 2022, 12:56:36 PM11/30/22
to
On Tue, 29 Nov 2022 19:12:44 +0000, Sam Plusnet <n...@home.com> wrote:

I've read a story or two where the rupture of a tank of
oxygen caused an explosion. Or was expected to.

Since there was no exposition about anything /plainly/
explosive in the environment, I wondered, each time, if
the writer was ignorant. Oxygen itself does not explode.

Now, "spontaneously combust" is not the same as "explode",
but I didn't know about the spontaneous combustion.

How often is a ruptured O2 tank likely to cause an explosion?

--
Rich Ulrich

Athel Cornish-Bowden

unread,
Nov 30, 2022, 1:18:56 PM11/30/22
to
On 2022-11-30 17:56:24 +0000, Rich Ulrich said:

> On Tue, 29 Nov 2022 19:12:44 +0000, Sam Plusnet <n...@home.com> wrote:
>
>> On 29-Nov-22 16:18, Bertel Lund Hansen wrote:
>>> Den 29.11.2022 kl. 08.48 skrev Bertel Lund Hansen:
>>>
>>>> Yes, because the hydrogen gets mixed with oxygene first. The first
>>>> explosion triggers the following ones.
>>>
>>> Sorry. I got misled by the name "hydrogen peroxid". It's oxygen that is
>>> released, and free oxygen will connect with any substance that can burn.
>>> The slightest spark wil trigger a violent fire or an explosion. It's
>>> more reactive because it is single oxygen atoms that are released, not
>>> the usual O2.
>>
>> Won't grease and oil spontaneously combust in a rich O2 atmosphere?
>> Torpedoes are usually well greased, to unsure they exit their tube
>> without any hang-ups.
>
> I've read a story or two where the rupture of a tank of
> oxygen caused an explosion. Or was expected to.
>
> Since there was no exposition about anything /plainly/
> explosive in the environment, I wondered, each time, if
> the writer was ignorant. Oxygen itself does not explode.

No, but things that are reasonably safe in air are much less so in
oxygen. A lighted cigarette will just smoulder in air, but it will
burst into flame in oxygen. Dust left after milling grain won't do
anything in air, but can explode in oxygen. Curiously, as one might
expect the opposite, pure hydrogen gas is indefinitely inert in oxygen
if not ignited.
>
> Now, "spontaneously combust" is not the same as "explode",
> but I didn't know about the spontaneous combustion.
>
> How often is a ruptured O2 tank likely to cause an explosion?


--
Athel -- French and British, living in Marseilles for 36+ years; mainly
in England until 1987.

Sam Plusnet

unread,
Nov 30, 2022, 2:17:16 PM11/30/22
to
On 30-Nov-22 17:56, Rich Ulrich wrote:
> On Tue, 29 Nov 2022 19:12:44 +0000, Sam Plusnet <n...@home.com> wrote:
>
>> On 29-Nov-22 16:18, Bertel Lund Hansen wrote:
>>> Den 29.11.2022 kl. 08.48 skrev Bertel Lund Hansen:
>>>
>>>> Yes, because the hydrogen gets mixed with oxygene first. The first
>>>> explosion triggers the following ones.
>>>
>>> Sorry. I got misled by the name "hydrogen peroxid". It's oxygen that is
>>> released, and free oxygen will connect with any substance that can burn.
>>> The slightest spark wil trigger a violent fire or an explosion. It's
>>> more reactive because it is single oxygen atoms that are released, not
>>> the usual O2.
>>
>> Won't grease and oil spontaneously combust in a rich O2 atmosphere?
>> Torpedoes are usually well greased, to unsure they exit their tube
>> without any hang-ups.
>
> I've read a story or two where the rupture of a tank of
> oxygen caused an explosion. Or was expected to.

I once watched an oxygen tank fall down two flights of metal emergency
exit-type stairs - and not rupture.
If it had done so, I would be unable to report on the situation.
>
> Since there was no exposition about anything /plainly/
> explosive in the environment, I wondered, each time, if
> the writer was ignorant. Oxygen itself does not explode.
>
> Now, "spontaneously combust" is not the same as "explode",
> but I didn't know about the spontaneous combustion.
>
> How often is a ruptured O2 tank likely to cause an explosion?
>
The O2 is under high pressure.
If the tank is damaged, then steel shrapnel may fly fast and far. The
rapid release of large amounts of O2 may cause nearby things to combust,
& cause secondary and unpredictable things to happen.

--
Sam Plusnet

Tony Cooper

unread,
Nov 30, 2022, 2:36:37 PM11/30/22
to
On the subject of explosions...yesterday a man rear-ended another
driver and his car then veered into a store that sells fireworks. The
building caught fire and exploded and was completely destroyed by the
fire. The driver died, but no one in the building was injured.

https://www.fox35orlando.com/video/1148409

There are better videos, but most are from sources that are behind
paywalls.

Bertel Lund Hansen

unread,
Nov 30, 2022, 2:55:05 PM11/30/22
to
Den 30.11.2022 kl. 20.17 skrev Sam Plusnet:

> The O2 is under high pressure.

200 bar.

> If the tank is damaged, then steel shrapnel may fly fast and far.  The
> rapid release of large amounts of O2 may cause nearby things to combust,
> & cause secondary and unpredictable things to happen.

If the valve part is knocked off, The container will fly like a rocket.

--
Bertel

J. J. Lodder

unread,
Nov 30, 2022, 3:00:43 PM11/30/22
to
An explosion is nothing but a large amount of energy
being liberated in a short time in a small volume.
It doesn't need to be a detonation.

An oxygen tank rupturing will not be an explosion, by itself,
but dust burning in the released oxygen may have an explosive effect,

Jan

lar3ryca

unread,
Nov 30, 2022, 3:09:08 PM11/30/22
to
Does an oxygen and hydrogen mixture 'spontaneously combust'?
I think it requires an ignition source... flame, spark, whatever.

> How often is a ruptured O2 tank likely to cause an explosion?

It's more likely to cause damage or injury from the thrust of the
escaping O₂, especially if the valve is detached.

There are quite a few examples shown on Youtube.

A few years ago I read of a fellow named George Goble (not George Gobel,
the comedian) whose hobby was lighting charcoal barbecues in the fastet
possible manner. He did this by placing a lit cigaratte into the
barbecue, piling about 30 or so lbs. of charcoal. He then filled the
bowl of a 10 (or more) ft. ladle with LOX. He would then pour the LOX
into the barbecue.

About 4 or 5 seconds later, after a spectacular 'explosion'[1] of
flame, the barbecue was ready to accept meat.

There are several examples of LOX-assisted burning.

Have a look at <https://youtu.be/8Ab3hyDKsj0?t=607>

This will take you to about 10:07, just before you will see a rapidly
expanding fire when a piece of LOX-soaked carpet is ignited.

[1] 'explosion', in my English is often used figuratively to describe a
very fast expansion of something, fire included.

--
Whenever you find yourself on the side of the majority, it is time to
pause and reflect.
—Mark Twain

Bertel Lund Hansen

unread,
Nov 30, 2022, 3:35:58 PM11/30/22
to
Den 30.11.2022 kl. 20.36 skrev Tony Cooper:

> On the subject of explosions...yesterday a man rear-ended another
> driver and his car then veered into a store that sells fireworks. The
> building caught fire and exploded and was completely destroyed by the
> fire. The driver died, but no one in the building was injured.

> https://www.fox35orlando.com/video/1148409

In 2004 there was a fire in a fireworks store in Seest near Kolding,
Denmark. You may have heard about it. Here is a video:

https://www.youtube.com/watch?v=FGpZn96MYi4

The store contained 800 ton of fireworks, much more than it was allowed
to store in one place. 366 houses were more or less destroyed. The
biggest explosion scored 2,2 on the Richter scale.

--
Bertel

J. J. Lodder

unread,
Nov 30, 2022, 4:13:31 PM11/30/22
to
Bertel Lund Hansen <gade...@lundhansen.dk> wrote:

And not just for oxygen cylinders.
Safety regulations say that all gas cylinders
should always be strapped to a solid support
to make falling over impossible.
In more civilised parts of the world
such regulations may actually be enforced,

Jan

--
For example:
<https://p.globalsources.com/IMAGES/PDT/B1124251134/1-CYLINDER-WALL-MOUNT-GAS-CYLINDER-BRACKET-Al.jpg>
For the physics-challenged: gas at 200 bar contains 20 MJ/m^3 in
potential energy, which is about 5 kg of TNT equivalent.
Or in Olyppic swimming pool units, about a hundred hand grenades.
Gas cylinders should really be handled with great care.

J. J. Lodder

unread,
Nov 30, 2022, 4:40:22 PM11/30/22
to
> escaping O?, especially if the valve is detached.
>
> There are quite a few examples shown on Youtube.
>
> A few years ago I read of a fellow named George Goble (not George Gobel,
> the comedian) whose hobby was lighting charcoal barbecues in the fastet
> possible manner. He did this by placing a lit cigaratte into the
> barbecue, piling about 30 or so lbs. of charcoal. He then filled the
> bowl of a 10 (or more) ft. ladle with LOX. He would then pour the LOX
> into the barbecue.
>
> About 4 or 5 seconds later, after a spectacular 'explosion'[1] of
> flame, the barbecue was ready to accept meat.

Yes, and it earned him an Ig-Nobel prize.
Note that the Ig-Nobels are (among other criteria)
for experiments that can not, or should not be replicated.

Really, don't try this at home.
There are already far too many barbeque accidents as it is,

Jan

Bertel Lund Hansen

unread,
Nov 30, 2022, 5:55:57 PM11/30/22
to
Den 30.11.2022 kl. 22.40 skrev J. J. Lodder:

> Yes, and it earned him an Ig-Nobel prize.

What does "Ig" stand for?

--
Bertel

Tony Cooper

unread,
Nov 30, 2022, 6:00:47 PM11/30/22
to
Nothing. It's a play on words. Ignoble is the opposite of noble, or,
in this case, the opposite of "Nobel".

Paul Wolff

unread,
Nov 30, 2022, 7:05:12 PM11/30/22
to
On Wed, 30 Nov 2022, at 21:00:38, J. J. Lodder posted:
English is fluid enough that there's no certain definition of what
qualifies as an explosion, but rapid expansion of a gas is essential,
and I'd say that if the expanding gas is preceded by a shock wave, it is
exploding. With no shock wave, it's just rapid expansion. I'm no expert,
but I associate a shock wave with expansion faster than the local speed
of sound.

A bullet driven out of a rifle barrel by the expanding gases of the
propellant could be considered driven by an explosion, but the
propellant doesn't explode within the barrel - it merely burns very
rapidly. The compressed hot gases explode on release at the muzzle.

The ruptured O2 tank is unlikely to cause an explosion unless the
chemistry of its surroundings conduces to it. By chemistry I mean
composition, temperature and pressure.
--
Paul W

Sam Plusnet

unread,
Nov 30, 2022, 8:05:12 PM11/30/22
to
On 30-Nov-22 21:13, J. J. Lodder wrote:
> Bertel Lund Hansen <gade...@lundhansen.dk> wrote:
>
>> Den 30.11.2022 kl. 20.17 skrev Sam Plusnet:
>>
>>> The O2 is under high pressure.
>>
>> 200 bar.
>>
>>> If the tank is damaged, then steel shrapnel may fly fast and far. The
>>> rapid release of large amounts of O2 may cause nearby things to combust,
>>> & cause secondary and unpredictable things to happen.
>>
>> If the valve part is knocked off, The container will fly like a rocket.
>
> And not just for oxygen cylinders.
> Safety regulations say that all gas cylinders
> should always be strapped to a solid support
> to make falling over impossible.
> In more civilised parts of the world
> such regulations may actually be enforced,

Now, yes.
But the (distant) past is a foreign country.

--
Sam Plusnet

J. J. Lodder

unread,
Dec 1, 2022, 3:56:00 AM12/1/22
to
Bertel Lund Hansen <gade...@lundhansen.dk> wrote:

They are the initials of Ignatius Nobel,
Alfred Nobel's lesser known brother,

Jan

J. J. Lodder

unread,
Dec 1, 2022, 5:55:51 AM12/1/22
to
Yes, of course, by the definition of 'shock wave'.

> A bullet driven out of a rifle barrel by the expanding gases of the
> propellant could be considered driven by an explosion, but the
> propellant doesn't explode within the barrel - it merely burns very
> rapidly. The compressed hot gases explode on release at the muzzle.

Yes, that came up in another thread a short while ago.
An explosive cannot serve a a propellant, since it will destroy the gun.
OTOH, large amounts of propellant can certainly explode,
if confined somehow. Even black powder will do.
(as Mr. Guy Fawkwes intended)

> The ruptured O2 tank is unlikely to cause an explosion unless the
> chemistry of its surroundings conduces to it. By chemistry I mean
> composition, temperature and pressure.

An large industrial steel bottle of 50 liter at 200 bar
contains about a megajoule in potential energy.
(as mentioned, that's about 5 hand grenades, in football field units)
If such a bottle falls over and ruptures
that energy is released in a very short time,
throwing perhaps some steel shards around too.
I think that those who will have to come in afterwards
to pick up what remains of the lab assistant who stood next to it
will call it an explosion. (even though it is 'merely' physics)

Jan


occam

unread,
Dec 1, 2022, 6:17:58 AM12/1/22
to
Yet, it is explosions (burning mixture of oxygen and petrol) in an
engine that propel the pistons that eventually propel a car. These
(albeit tiny) explosions are what combustion engines are about.


> OTOH, large amounts of propellant can certainly explode,

...as can small, controlled amounts.

Bertel Lund Hansen

unread,
Dec 1, 2022, 6:57:21 AM12/1/22
to
Den 01.12.2022 kl. 12.17 skrev occam:

> Yet, it is explosions (burning mixture of oxygen and petrol) in an
> engine that propel the pistons that eventually propel a car. These
> (albeit tiny) explosions are what combustion engines are about.

I don't think that that is correct. Like with the gun, exoplosions would
destroy the motor. It is a fast burning.

For many years the car engine has in Denmark been called "en
eksplosionsmotor", so many people do believe that the gas explodes, but
it doesn't.

--
Bertel

lar3ryca

unread,
Dec 1, 2022, 8:27:41 AM12/1/22
to
My favourite names of the cycles of a 4-cycle engine...

Suck, Squeeze, Bang, and Blow.

--
After obsessively Googling symptoms for four hours, I discovered
“obsessively Googling symptoms” is a symptom of hypochondria.”
- Stephen Colbert

J. J. Lodder

unread,
Dec 1, 2022, 9:39:32 AM12/1/22
to
That is an ineradicable misunderstanding.
It probably came about because the inventor of the thing,
Christiaan Huygens, proposed using gunpowder as the fuel.
(lacking anything else) It wasn't practical.
As a result the thing is still called some equivalent of
'explosion engine', in many languages.
A much better, and correct name is 'interal combustion engine'.

> > OTOH, large amounts of propellant can certainly explode,
>
> ...as can small, controlled amounts.

Certainy, see fireworks displays.
However, for the sharp explosion sound
one uses fine aluminium power mixed with an oxidiser.

Jan

Tak To

unread,
Dec 1, 2022, 12:45:25 PM12/1/22
to
On 11/29/2022 11:18 AM, Bertel Lund Hansen wrote:
> Den 29.11.2022 kl. 08.48 skrev Bertel Lund Hansen:
>
>> Yes, because the hydrogen gets mixed with oxygene first. The first
>> explosion triggers the following ones.
>
> Sorry. I got misled by the name "hydrogen peroxid". It's oxygen that is
> released, and free oxygen will connect with any substance that can burn.
> The slightest spark wil trigger a violent fire or an explosion. It's
> more reactive because it is single oxygen atoms that are released, not
> the usual O2.

Nascent oxygen.

<ObAUE>

That was how I learned the word "nascent". And in my work as
a software designer, I find "nascent" quite handy as a name
of an abstract state.

</>

--
Tak
----------------------------------------------------------------+-----
Tak To ta...@alum.mit.eduxx
--------------------------------------------------------------------^^
[taode takto ~{LU5B~}] NB: trim the xx to get my real email addr

Paul Wolff

unread,
Dec 1, 2022, 12:51:53 PM12/1/22
to
On Thu, 1 Dec 2022, at 15:39:27, J. J. Lodder posted:
Correct, there are no small explosions in a properly regulated internal
combustion engine. When they occur, the audible detonations are called
'pinking' (or 'knocking') in BrE. As I recall, relevant factors are
incorrect ignition timing, too great a compression ratio, and perhaps an
incorrect fuel/air ratio too.

I'm pretty confident as regards petrol engines, but I don't properly
understand how diesel engines differ. Adiabatic heating by compression I
think, but where's the controlled ignition initiated?
--
Paul W

Tak To

unread,
Dec 1, 2022, 1:16:27 PM12/1/22
to
On 11/29/2022 11:53 AM, Mack A. Damia wrote:
> [...]
> Much of the film must have been fictionalized. I am unaware that the
> sub was in touch with the outside world after the explosion, so how
> did anybody know what was happening?

Previous I thought /The Command/ (/Kursk/ in UK) was a remake of
/K-19: The Widowmaker/ (Harrison Ford, Liam Neeson). Alas I was
wrong. They were based on two different incidents -- in 2000
and 1961 respectively.

The incident in 1985 (nuclear accident in a K-431 submarine)
has no film version so far.

Tak To

unread,
Dec 1, 2022, 1:35:42 PM12/1/22
to
On 11/30/2022 1:18 PM, Athel Cornish-Bowden wrote:
> [...]
>
> A lighted cigarette will just smoulder in air, but it will
> burst into flame in oxygen.

Common demonstration in high school chemistry classes.

> Dust left after milling grain won't do
> anything in air, but can explode in oxygen.

My understanding is that a large amount of fine grain powder
(or that of of any kind of combustible material) suspended in
the air can easily cause an explosion should a spark appear.
I don't think grain powder can combust spontaneously even
in pure O2.

> Curiously, as one might
> expect the opposite, pure hydrogen gas is indefinitely inert in oxygen
> if not ignited.

I doubt that carbon is more reactive than hydrogen.

Peter T. Daniels

unread,
Dec 1, 2022, 1:37:11 PM12/1/22
to
On Thursday, December 1, 2022 at 12:51:53 PM UTC-5, Paul Wolff wrote:
> On Thu, 1 Dec 2022, at 15:39:27, J. J. Lodder posted:

> >The thing is still called some equivalent of 'explosion engine', in
> >many languages.
> >A much better, and correct name is 'interal combustion engine'.

The ordinary term (almost) in AmE.

> Correct, there are no small explosions in a properly regulated internal
> combustion engine. When they occur, the audible detonations are called
> 'pinking' (or 'knocking') in BrE. As I recall, relevant factors are
> incorrect ignition timing, too great a compression ratio, and perhaps an
> incorrect fuel/air ratio too.

Aha -- now I know what to tell the mechanic. (I had no idea what
either "pinging" or "knocking" was.) It does it, primarily before
being properly warmed up, occasionally when shifting from 1st
to 2nd or from 2nd to 3rd (but not, yet anyway, to 4th or 5th). I
think my gas mileage has gone down significantly, but the odometer
died years ago (the speedometer remains accurate), and the tach
seems to be at a higher level than usual for ordinary speeds.

> I'm pretty confident as regards petrol engines, but I don't properly
> understand how diesel engines differ. Adiabatic heating by compression I
> think, but where's the controlled ignition initiated?

Seen this morning: gas is down to $3.37/gal.! (~84c/liter).

Jerry Friedman

unread,
Dec 1, 2022, 1:46:58 PM12/1/22
to
On Thursday, December 1, 2022 at 10:51:53 AM UTC-7, Paul Wolff wrote:
> On Thu, 1 Dec 2022, at 15:39:27, J. J. Lodder posted:
> >occam <oc...@nowhere.nix> wrote:
> >
> >> On 01/12/2022 11:55, J. J. Lodder wrote:
...

> >> > An explosive cannot serve a a propellant, since it will destroy the gun.
> >>
> >> Yet, it is explosions (burning mixture of oxygen and petrol) in an
> >> engine that propel the pistons that eventually propel a car. These
> >> (albeit tiny) explosions are what combustion engines are about.
> >
> >That is an ineradicable misunderstanding.
> >It probably came about because the inventor of the thing,
> >Christiaan Huygens, proposed using gunpowder as the fuel.
> >(lacking anything else) It wasn't practical.
> >As a result the thing is still called some equivalent of
> >'explosion engine', in many languages.
> >A much better, and correct name is 'interal combustion engine'.
> >
> Correct, there are no small explosions in a properly regulated internal
> combustion engine. When they occur, the audible detonations are called
> 'pinking' (or 'knocking') in BrE. As I recall, relevant factors are
> incorrect ignition timing, too great a compression ratio, and perhaps an
> incorrect fuel/air ratio too.

And fuel that's too easily ignited, that is, too low-octane.

> I'm pretty confident as regards petrol engines, but I don't properly
> understand how diesel engines differ. Adiabatic heating by compression I
> think, but where's the controlled ignition initiated?

My impression from Wikipedia is that air without fuel is compressed in
the cylinder so its temperature rises above the ignition point, and then
fuel is injected.

--
Jerry Friedman

lar3ryca

unread,
Dec 1, 2022, 1:57:48 PM12/1/22
to
"pinging" in my English.

> in BrE. As I recall, relevant factors are
> incorrect ignition timing, too great a compression ratio, and perhaps an
> incorrect fuel/air ratio too.

> I'm pretty confident as regards petrol engines, but I don't properly
> understand how diesel engines differ. Adiabatic heating by compression I
> think, but where's the controlled ignition initiated?

--
For sale. CD of Snoozy McGregor's Bagpipe Lullabies.

Tak To

unread,
Dec 1, 2022, 2:06:01 PM12/1/22
to
Shock wave is just faster than sound propagation.

> A bullet driven out of a rifle barrel by the expanding gases of the
> propellant could be considered driven by an explosion, but the
> propellant doesn't explode within the barrel - it merely burns very
> rapidly. The compressed hot gases explode on release at the muzzle.
>
> The ruptured O2 tank is unlikely to cause an explosion unless the
> chemistry of its surroundings conduces to it. By chemistry I mean
> composition, temperature and pressure.

Chemistry *and* physics?

J. J. Lodder

unread,
Dec 1, 2022, 2:12:08 PM12/1/22
to
Bertel Lund Hansen <gade...@lundhansen.dk> wrote:

> Den 01.12.2022 kl. 12.17 skrev occam:
>
> > Yet, it is explosions (burning mixture of oxygen and petrol) in an
> > engine that propel the pistons that eventually propel a car. These
> > (albeit tiny) explosions are what combustion engines are about.
>
> I don't think that that is correct. Like with the gun, exoplosions would
> destroy the motor. It is a fast burning.

Yes, that is called 'knocking' in English.
It will indeed destroy the engine if allowed to go on
Mixture and ignition must be set in ways that avoid it.
Modern computerised engine management systems rely on a knock sensor,

Jan

Bertel Lund Hansen

unread,
Dec 1, 2022, 2:24:17 PM12/1/22
to
Den 01.12.2022 kl. 19.35 skrev Tak To:

> My understanding is that a large amount of fine grain powder
> (or that of of any kind of combustible material) suspended in
> the air can easily cause an explosion should a spark appear.

That is true. Old ventilation systems sometimes explode because the dust
has collected through the years, and static electricity can easily occur.

https://www.grupa-wolff.com/a-tragic-flour-explosion/

--
Bertel

Bertel Lund Hansen

unread,
Dec 1, 2022, 2:31:04 PM12/1/22
to
Den 01.12.2022 kl. 18.41 skrev Paul Wolff:

> Correct, there are no small explosions in a properly regulated internal
> combustion engine. When they occur, the audible detonations are called
> 'pinking' (or 'knocking') in BrE.

Can that be true? The fuel is the same in both cases.

As I understand it knocking may occur if the motor is fed fuel with too
low octane value. Then the compression will ignite the fuel before the
spark is turned on. The burning process must be the same as with normal
operation, but it occurs while the piston is moving upwards, so it
reacts against the pistons movement thereby producing the knocking sound
and a destructive force on the mechanic system.

--
Bertel

Paul Wolff

unread,
Dec 1, 2022, 2:31:56 PM12/1/22
to
On Thu, 1 Dec 2022, at 10:46:55, Jerry Friedman posted:
>On Thursday, December 1, 2022 at 10:51:53 AM UTC-7, Paul Wolff wrote:
>> On Thu, 1 Dec 2022, at 15:39:27, J. J. Lodder posted:
>> >occam <oc...@nowhere.nix> wrote:
>> >> On 01/12/2022 11:55, J. J. Lodder wrote:
>...
>> >> > An explosive cannot serve a a propellant, since it will destroy
>> >> >the gun.
>> >>
>> >> Yet, it is explosions (burning mixture of oxygen and petrol) in an
>> >> engine that propel the pistons that eventually propel a car. These
>> >> (albeit tiny) explosions are what combustion engines are about.
>> >
>> >That is an ineradicable misunderstanding.
>> >It probably came about because the inventor of the thing,
>> >Christiaan Huygens, proposed using gunpowder as the fuel.
>> >(lacking anything else) It wasn't practical.
>> >As a result the thing is still called some equivalent of
>> >'explosion engine', in many languages.
>> >A much better, and correct name is 'interal combustion engine'.
>> >
>> Correct, there are no small explosions in a properly regulated internal
>> combustion engine. When they occur, the audible detonations are called
>> 'pinking' (or 'knocking') in BrE. As I recall, relevant factors are
>> incorrect ignition timing, too great a compression ratio, and perhaps an
>> incorrect fuel/air ratio too.
>
>And fuel that's too easily ignited, that is, too low-octane.

That would be the converse of (inverse of? the opposite way of looking
at, anyway) too great a compression ratio.
>
>> I'm pretty confident as regards petrol engines, but I don't properly
>> understand how diesel engines differ. Adiabatic heating by compression I
>> think, but where's the controlled ignition initiated?
>
>My impression from Wikipedia is that air without fuel is compressed in
>the cylinder so its temperature rises above the ignition point, and then
>fuel is injected.
>
So it's a flame injection variety of fuel injection, I suppose. Why not?
--
Paul W

Paul Wolff

unread,
Dec 1, 2022, 2:31:56 PM12/1/22
to
On Thu, 1 Dec 2022, at 14:05:56, Tak To posted:
If you like. I don't know of any chemistry without physics, from
molecular wave functions to thermodynamics and plenty more besides. As a
chemist I see all chemistry against a physics background.
--
Paul W

Bertel Lund Hansen

unread,
Dec 1, 2022, 2:32:54 PM12/1/22
to
Den 01.12.2022 kl. 19.46 skrev Jerry Friedman:

> My impression from Wikipedia is that air without fuel is compressed in
> the cylinder so its temperature rises above the ignition point, and then
> fuel is injected.

How do you inject fuel if the chamber is under high pressure?

My understanding is that the fuel and air are mixed in the normal manner
and then compressed.

--
Bertel

Bertel Lund Hansen

unread,
Dec 1, 2022, 2:36:29 PM12/1/22
to
Den 01.12.2022 kl. 20.29 skrev Paul Wolff:

> If you like. I don't know of any chemistry without physics, from
> molecular wave functions to thermodynamics and plenty more besides. As a
> chemist I see all chemistry against a physics background.

As I see it any distinction between chemistry and physics is arbitrary.
That doesn't mean that it can't be meaningful in a certain context.

--
Bertel

J. J. Lodder

unread,
Dec 1, 2022, 2:45:23 PM12/1/22
to
Depends, on how old it is.
Modern diesels do it with timed direct injection of the fuel
into the already compresed air,

Jan


J. J. Lodder

unread,
Dec 1, 2022, 2:50:37 PM12/1/22
to
Bertel Lund Hansen <gade...@lundhansen.dk> wrote:

> Den 01.12.2022 kl. 19.46 skrev Jerry Friedman:
>
> > My impression from Wikipedia is that air without fuel is compressed in
> > the cylinder so its temperature rises above the ignition point, and then
> > fuel is injected.
>
> How do you inject fuel if the chamber is under high pressure?

By applying more pressure.

> My understanding is that the fuel and air are mixed in the normal manner
> and then compressed.

You are mistaken,

Jan

Paul Wolff

unread,
Dec 1, 2022, 2:51:58 PM12/1/22
to
On Thu, 1 Dec 2022, at 20:30:59, Bertel Lund Hansen posted:
Spark ignition is /always/ before top dead centre of the piston travel.
It's half a century since I played with motorcycle engine tuning, but
distant memory says about 18 degrees (rotational) before TDC wouldn't be
far off.
--
Paul W

Jerry Friedman

unread,
Dec 1, 2022, 4:37:08 PM12/1/22
to
...

True, although if you're trying to find the source of the problem, there's a
difference between too high a compression ratio caused by gunk in the
engine and too inflammable a fuel caused by cheeseparing at the pump.

--
Jerry Friedman

J. J. Lodder

unread,
Dec 1, 2022, 4:49:54 PM12/1/22
to
Yes. But cosines of small angles being nearly one
the mixture is already close to max compression.
Ignition before TDC gives the burn the time
to build up pressure to act on the downstroke.

Some ancient engines had an adjust screw for the timing.
If you had been forced to buy poor quality fuel
you could advance the timing manually to avoid knocking,

Jan


Paul Wolff

unread,
Dec 1, 2022, 6:42:07 PM12/1/22
to
On Thu, 1 Dec 2022, at 22:49:50, J. J. Lodder posted:
You're right - I remember an old BSA with a small rotary lever on the
handlebar operating a Bowden cable to advance/retard the timing. Perhaps
it was retarded during the kick-start process to avoid painful kick-back
from a slowly turning engine - it was a big single-cylinder machine.

The other kick-starting aid was an exhaust valve lifter.
--
Paul W

Peter Moylan

unread,
Dec 1, 2022, 6:49:18 PM12/1/22
to
On 02/12/22 04:41, Paul Wolff wrote:
>
> I'm pretty confident as regards petrol engines, but I don't properly
> understand how diesel engines differ. Adiabatic heating by
> compression I think, but where's the controlled ignition initiated?

That detail was definitely covered when I did a third-year
thermodynamics subject, but now I find that most of that information has
slipped from my mind.

(That was thermodynamics taught in a mechanical engineering department,
by the way. Totally different from thermodynamics as taught by a physicist.)

It's probably because I never taught that subject. Most of what I know
about electrical engineering comes from having to teach it.

--
Peter Moylan Newcastle, NSW http://www.pmoylan.org

Peter Moylan

unread,
Dec 1, 2022, 7:11:38 PM12/1/22
to
On 02/12/22 08:49, J. J. Lodder wrote:

> Some ancient engines had an adjust screw for the timing. If you had
> been forced to buy poor quality fuel you could advance the timing
> manually to avoid knocking,

A very distant memory tells me that the advance/retard control was on
the steering wheel of our family's first car, or anyway somewhere near
the steering wheel. It had to be set in a certain way (and so did the
choke) before turning the crank handle, and then readjusted after
getting into the car.

That was a 1930s-era car, though.

lar3ryca

unread,
Dec 1, 2022, 7:50:19 PM12/1/22
to
On 2022-12-01 11:41, Paul Wolff wrote:
There is at least 1 'diesel' engine that ignites by compression of
already mixed fuel and air.

It is a common 2-stroke model aircraft engine. One needs to heat a 'glow
plug' in order to start it, as the compression is not sufficient to
start it when the engine is cold.

Once it starts, the heat of the engine and the action of the glow plug
is enough to ignite the mixture.

--
To decode this comment into a readable form, rot13 it twice.

Tak To

unread,
Dec 1, 2022, 9:54:14 PM12/1/22
to
The fuel catches fire when it comes out from the nozzle
as a mist, I think.

Mark Brader

unread,
Dec 1, 2022, 10:14:21 PM12/1/22
to
Tak To:
> > My understanding is that a large amount of fine grain powder
> > (or that of of any kind of combustible material) suspended in
> > the air can easily cause an explosion should a spark appear.

I remember an experiment to demonstrate this, involving a coffee
can with a hole made in the bottom, a rubber tube connected to
the hole, a quantity of flour blown through the tube, and a
small candle left burning inside the can as an ignition source.

It made a nice bang.

Bertel Lund Hansen:
> That is true. Old ventilation systems sometimes explode because the dust
> has collected through the years, and static electricity can easily occur.

The usual place for this type of explosion is grain elevators.

> https://www.grupa-wolff.com/a-tragic-flour-explosion/

Okay, close enough.
--
Mark Brader | I like when things catch fire and explode,
Toronto | which means I do not have your best interests in mind.
m...@vex.net | --Randall Munroe

My text in this article is in the public domain.

Mark Brader

unread,
Dec 1, 2022, 10:16:00 PM12/1/22
to
Bertel Lund Hansen:
> > ...It's oxygen that is
> > released, and free oxygen will connect with any substance that can burn.
> > The slightest spark wil trigger a violent fire or an explosion. It's
> > more reactive because it is single oxygen atoms that are released, not
> > the usual O2.

Tak To:
> Nascent oxygen.

Atomic or monatomic oxygen.

> <ObAUE>
>
> That was how I learned the word "nascent".

I've never heard it in such a context.
--
Mark Brader, Toronto | "I like work; it fascinates me. I can sit and
m...@vex.net | look at it for hours." -- Jerome K. Jerome

lar3ryca

unread,
Dec 1, 2022, 10:43:07 PM12/1/22
to
On 2022-12-01 21:14, Mark Brader wrote:
> Tak To:
>>> My understanding is that a large amount of fine grain powder
>>> (or that of of any kind of combustible material) suspended in
>>> the air can easily cause an explosion should a spark appear.
>
> I remember an experiment to demonstrate this, involving a coffee
> can with a hole made in the bottom, a rubber tube connected to
> the hole, a quantity of flour blown through the tube, and a
> small candle left burning inside the can as an ignition source.
>
> It made a nice bang.
>
> Bertel Lund Hansen:
>> That is true. Old ventilation systems sometimes explode because the dust
>> has collected through the years, and static electricity can easily occur.
>
> The usual place for this type of explosion is grain elevators.

I was asleep at a girlfriend's place in North Vancouver one morning in
1975, when I was awakened by both the sound and the vibration of an
explosion in a grain elevator. I swear the apartment building swayed. I
nearly fell out of bed.
Chris: Hey can I borrow a ten?
Kristen: Sure.
Christen: Thank you.
Kris: You're welcome.

Jerry Friedman

unread,
Dec 1, 2022, 10:59:06 PM12/1/22
to
On Thursday, December 1, 2022 at 8:16:00 PM UTC-7, Mark Brader wrote:
> Bertel Lund Hansen:
> > > ...It's oxygen that is
> > > released, and free oxygen will connect with any substance that can burn.
> > > The slightest spark wil trigger a violent fire or an explosion. It's
> > > more reactive because it is single oxygen atoms that are released, not
> > > the usual O2.
> Tak To:
> > Nascent oxygen.
>
> Atomic or monatomic oxygen.
>
> > <ObAUE>
> >
> > That was how I learned the word "nascent".
>
> I've never heard it in such a context.

That's where I learned the word from a children's science book c. 1970.
I have no information on whether it's used by adult scientists c. 2022.

--
Jerry Friedman

Bertel Lund Hansen

unread,
Dec 1, 2022, 11:49:36 PM12/1/22
to
Den 01.12.2022 kl. 20.48 skrev Paul Wolff:

>> As I understand it knocking may occur if the motor is fed fuel with
>> too low octane value. Then the compression will ignite the fuel before
>> the spark is turned on. The burning process must be the same as with
>> normal operation, but it occurs while the piston is moving upwards, so
>> it reacts against the pistons movement thereby producing the knocking
>> sound and a destructive force on the mechanic system.
>>
> Spark ignition is /always/ before top dead centre of the piston travel.
> It's half a century since I played with motorcycle engine tuning, but
> distant memory says about 18 degrees (rotational) before TDC wouldn't be
> far off.

Yes, because it is timed so the strongest force is present just as the
piston reaches the top. Knocking occurs if the ignition starts sooner
than normal so the strongest force works against the piston (and car)
movement.

--
Bertel

Bertel Lund Hansen

unread,
Dec 1, 2022, 11:53:53 PM12/1/22
to
Den 02.12.2022 kl. 01.11 skrev Peter Moylan:

> A very distant memory tells me that the advance/retard control was on
> the steering wheel of our family's first car, or anyway somewhere near
> the steering wheel. It had to be set in a certain way (and so did the
> choke) before turning the crank handle, and then readjusted after
> getting into the car.
>
> That was a 1930s-era car, though.

My parent's first car was from 1931. It was a chevy. It didn't have this
angle control, but it of course had a choke.

--
Bertel

Bertel Lund Hansen

unread,
Dec 1, 2022, 11:58:16 PM12/1/22
to
Den 02.12.2022 kl. 01.50 skrev lar3ryca:

> There is at least 1 'diesel' engine that ignites by compression of
> already mixed fuel and air.

Didn't all old diesel motors work this way? That's what I have been told.

--
Bertel

bil...@shaw.ca

unread,
Dec 2, 2022, 1:04:58 AM12/2/22
to
On Wednesday, November 30, 2022 at 5:05:12 PM UTC-8, Sam Plusnet wrote:
> On 30-Nov-22 21:13, J. J. Lodder wrote:
> > Bertel Lund Hansen <gade...@lundhansen.dk> wrote:
> >
> >> Den 30.11.2022 kl. 20.17 skrev Sam Plusnet:
> >>
> >>> The O2 is under high pressure.
> >>
> >> 200 bar.
> >>
> >>> If the tank is damaged, then steel shrapnel may fly fast and far. The
> >>> rapid release of large amounts of O2 may cause nearby things to combust,
> >>> & cause secondary and unpredictable things to happen.
> >>
> >> If the valve part is knocked off, The container will fly like a rocket.
> >
> > And not just for oxygen cylinders.
> > Safety regulations say that all gas cylinders
> > should always be strapped to a solid support
> > to make falling over impossible.
> > In more civilised parts of the world
> > such regulations may actually be enforced,
> Now, yes.
> But the (distant) past is a foreign country.
>
How do they do things there?

bill

Peter Moylan

unread,
Dec 2, 2022, 2:09:29 AM12/2/22
to
I think that was true when I studied that subject, but that was back in
1967. We've passed a lot of water over the bridge since then.

Bertel Lund Hansen

unread,
Dec 2, 2022, 2:50:03 AM12/2/22
to
Den 02.12.2022 kl. 08.09 skrev Peter Moylan:

>>> There is at least 1 'diesel' engine that ignites by compression of
>>>  already mixed fuel and air.
>>
>> Didn't all old diesel motors work this way? That's what I have been
>> told.
>
> I think that was true when I studied that subject, but that was back in
> 1967. We've passed a lot of water over the bridge since then.

My little sister worked as a taxi driver in the beginning of the 70's.
She drove mostly Mercs. She explained to me that she had to park the
cars with the handbrake activated. The 'style' in our family was to park
the car in first gear or reverse gear. The Mercs would roll and
selfstart if parked this way on a (slight) hill.

Isn't that proof that the motor worked as I explained.

--
Bertel

Richard Heathfield

unread,
Dec 2, 2022, 3:11:23 AM12/2/22
to
On 02/12/2022 7:49 am, Bertel Lund Hansen wrote:
> Den 02.12.2022 kl. 08.09 skrev Peter Moylan:
>
>>>> There is at least 1 'diesel' engine that ignites by
>>>> compression of
>>>>  already mixed fuel and air.
>>>
>>> Didn't all old diesel motors work this way? That's what I have
>>> been
>>> told.
>>
>> I think that was true when I studied that subject, but that was
>> back in
>> 1967. We've passed a lot of water over the bridge since then.
>
> My little sister worked as a taxi driver in the beginning of the
> 70's. She drove mostly Mercs. She explained to me that she had to
> park the cars with the handbrake activated.

In the UK, this is required. Rule 239 of the Highway Code "you
MUST apply the handbrake before leaving the vehicle", or if you
prefer Section 107 of The Road Vehicles (Construction and Use)
Regulations 1986 - "(1) Save as provided in paragraph (2), no
person shall leave, or cause or permit to be left, on a road a
motor vehicle which is not attended by a person licensed to drive
it unless the engine is stopped and any parking brake with which
the vehicle is required to be equipped is effectively set."

> The 'style' in our
> family was to park the car in first gear or reverse gear. The
> Mercs would roll and selfstart if parked this way on a (slight)
> hill.
>
> Isn't that proof that the motor worked as I explained.

No. It is, at most, proof that you should apply the handbrake
before leaving the vehicle unattended.

--
Richard Heathfield
Email: rjh at cpax dot org dot uk
"Usenet is a strange place" - dmr 29 July 1999
Sig line 4 vacant - apply within

Hibou

unread,
Dec 2, 2022, 3:26:48 AM12/2/22
to
Le 02/12/2022 à 07:49, Bertel Lund Hansen a écrit :
> Den 02.12.2022 kl. 08.09 skrev Peter Moylan:
> [...]
Diesel engines are compression-ignition engines, that's right, but your
story does raise some questions. First and reverse gear are usually low
enough that gear-multiplied engine-compression stops a car from running
away on a slight hill - that is the reason for engaging them when
parked, as a back-up to the handbrake. (This for a manual gearbox; there
was nothing to stop an automatic with a torque converter from running
away if not left in 'park' or with the handbrake on.)

Also, it was usual to have to activate and wait for glow plugs to do
their stuff when starting from cold - though not from hot, it's true.

And there would be a solenoid-operated fuel-valve that would cut the
supply to the injection pump when the 'ignition' switch was off. This
was how the engine was stopped (there was usually or always a lever on
the injection pump to cut the fuel in the same way). A hot engine might
possibly cough, but could not run.

charles

unread,
Dec 2, 2022, 5:30:17 AM12/2/22
to
In article <tmbehn$2t4tn$1...@dont-email.me>,
In the 2nd year of my (Engineering) degree course a lecturer began by
saying 2Since you've all got A-Level Chemistry ...."
I thought "I have never done any Chemistry in my life."

--
from KT24 in Surrey, England - sent from my RISC OS 4té
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

J. J. Lodder

unread,
Dec 2, 2022, 6:16:32 AM12/2/22
to
That isn't a diesel. The 'glow plug' isn't just for starting.
It remains glowing red hot as long as the engine is running.
So it functions as a spark plug that is permanently on.
It is just another kind of petrol engine,
running on special racing fuel that ignites easily,

Jan

J. J. Lodder

unread,
Dec 2, 2022, 6:16:32 AM12/2/22
to
That certainly was an issue.
I remember reading about crank starting engines,
either really old cars from before electric starters
or later cars with a run down battery. (that still had a handle)

Instruction booklets said things like:
ALWAYS be sure to have your thumbs ON THE SAME SIDE
of the crank handle as your fingers, otherwise SEVERE INJURY
may result.
The kick-back from the engine could dislocate or even break thumbs. [1]

> The other kick-starting aid was an exhaust valve lifter.

Still in existence on some modern 2-stroke chain saws
and other 2-stroke portable equipment.
There is no exhaust valve of course,
but there is a valve in the cylinder head
that can be opened for easier starting.
The first ignition forces it permanently shut again.

Jan

[1] Trivia: My driving instructor, long ago, taught me the same
about holding the steering wheel. Never have your thumbs inside.
He had been taught to drive in the army, on old Land Rovers probably.
Hitting a deep hole could give a kick-back to the steering wheel.
Very out of date knowledge by know, but the folklore lives on.

J. J. Lodder

unread,
Dec 2, 2022, 6:16:32 AM12/2/22
to
Now we are getting real old. My grandfather's pre-war motorcycle
had a mixture control as well. (or so he told me)

More trivia: his driver's exam consisted of driving a figure-8
on a sloping road, while giving the prescribed hand signals
when making the turns.

Jan




It is loading more messages.
0 new messages