It's 31 degrees centigrade in my dining room where I keep my planted
aquarium. It's rather hot today! So at what temperature will my CO2
canister likely to "unload" its contents? According to the pressure
gauge, it's over 70 bar. I have just read that the critical temperature
is 31.6 degrees or 88.88 degrees F. Should I be worried?

Nikki

In rec.aquaria.tech Nikki Casali wrote:
It's 31 degrees centigrade in my dining room where I keep my planted
aquarium. It's rather hot today! So at what temperature will my CO2
canister likely to "unload" its contents? According to the pressure
gauge, it's over 70 bar. I have just read that the critical temperature
is 31.6 degrees or 88.88 degrees F. Should I be worried?

It's essentially a gas.
It's not going to 'boil off' at one specific temperature.
I suspect that a blow-out plug will activate somewhere around 150C.

Nikki Casali wrote:
It's 31 degrees centigrade in my dining room where I keep my planted
aquarium. It's rather hot today! So at what temperature will my CO2
canister likely to "unload" its contents? According to the pressure
gauge, it's over 70 bar. I have just read that the critical temperature
is 31.6 degrees or 88.88 degrees F. Should I be worried?

I probably wouldn't worry about it much. CO2 cylinders are used for
fountain soda dispensers, and if we had them exploding whenever the
temperature got above 90F, we'd hear about it more often. (Soda machine
at a fair, outdoors on a summers day ...)

Also when a scientist talks about a "critical temperature" for a
substance, what that means is just that above the 32C temperature the
distinction between a liquid and a gas disappears. (At 70 atm and 25C,
CO2 is in it's liquid form. If you were able to see inside the tank,
you'd have liquid CO2 on the bottom, and gasseous CO2 on top. As you
heat the tank past 31C, the interface between the liquid and the gas
would start to shimmer & get diffuse. At 32C, the interface disappears
entirely. The fluid in the tank at that point is neither a liquid or a
gas, but exhibits properties of both.) It's an interesting property of
gasses/liquids, but it doesn't mean that your tank will explode.

Look at the pressure rating of your tank, and when the gauge reads close
to that, then start to worry.

P.S. Supercritical CO2 is used in a bunch of industrial processes,
including drycleaning and coffee decaffination.

Rocco Moretti wrote:
Nikki Casali wrote:

It's 31 degrees centigrade in my dining room where I keep my planted
aquarium. It's rather hot today! So at what temperature will my CO2
canister likely to "unload" its contents? According to the pressure
gauge, it's over 70 bar. I have just read that the critical
temperature is 31.6 degrees or 88.88 degrees F. Should I be worried?


I probably wouldn't worry about it much. CO2 cylinders are used for
fountain soda dispensers, and if we had them exploding whenever the
temperature got above 90F, we'd hear about it more often. (Soda machine
at a fair, outdoors on a summers day ...)

Also when a scientist talks about a "critical temperature" for a
substance, what that means is just that above the 32C temperature the
distinction between a liquid and a gas disappears. (At 70 atm and 25C,
CO2 is in it's liquid form. If you were able to see inside the tank,
you'd have liquid CO2 on the bottom, and gasseous CO2 on top. As you
heat the tank past 31C, the interface between the liquid and the gas
would start to shimmer & get diffuse. At 32C, the interface disappears
entirely. The fluid in the tank at that point is neither a liquid or a
gas, but exhibits properties of both.) It's an interesting property of
gasses/liquids, but it doesn't mean that your tank will explode.

Look at the pressure rating of your tank, and when the gauge reads close
to that, then start to worry.

P.S. Supercritical CO2 is used in a bunch of industrial processes,
including drycleaning and coffee decaffination.

What about this safety valve I keep hearing about that sometimes blows
out in a hot car or room? I'm worried about that one. It sounds like a
jet taking off when it happens, apparently.

Nikki

What about this safety valve I keep hearing about that sometimes blows
out in a hot car or room? I'm worried about that one. It sounds like a
jet taking off when it happens, apparently.

Nikki

It's a burst disk, rather than a valve. Opens once, then needs to be
replaced. The minimum blowout pressure for a CO2 cylinder is usually
something above 150 bar.

There are two ways to reach that pressure in a CO2 cylinder:
1) Grossly overheat the cylinder.
2) Overfill and somewhat overheat the cylinder.

Leaving a full cylinder in a closed car in the sun where temperatures
are reputed to reach 60 degrees within a few minutes will fulfill #1.
Even at 49 degrees a 100% full cylinder will only be at around 135
bar.

At 32 degrees a cylinder will reach 150 bar if it is 125% over filled.
What are the chances that simultaneously your fill station attendant
screwed up, and you have a day that warm in the U.K.? (Just teasing -
I live on the Wet Coast of Canada.)

In addition to the soda fountains and beer dispensers mentioned by the
previous poster, there are also thousands of CO2 fire extinguishers
surrounding us fitted with the same burst disk arrangement. Burst disk
rupture is a rare event that usually has to be worked towards.

It occurs to me that burst disks are only required on SCUBA cylinders
in North America, not in Europe. It might very well be that you don't
have them on CO2 cylinders either. No worries, eh?

Nikki Casali wrote:
Rocco Moretti wrote:

Nikki Casali wrote:

It's 31 degrees centigrade in my dining room where I keep my planted
aquarium. It's rather hot today! So at what temperature will my CO2
canister likely to "unload" its contents? According to the pressure
gauge, it's over 70 bar. I have just read that the critical
temperature is 31.6 degrees or 88.88 degrees F. Should I be worried?



I probably wouldn't worry about it much. CO2 cylinders are used for
fountain soda dispensers, and if we had them exploding whenever the
temperature got above 90F, we'd hear about it more often. (Soda
machine at a fair, outdoors on a summers day ...)

Also when a scientist talks about a "critical temperature" for a
substance, what that means is just that above the 32C temperature the
distinction between a liquid and a gas disappears. (At 70 atm and 25C,
CO2 is in it's liquid form. If you were able to see inside the tank,
you'd have liquid CO2 on the bottom, and gasseous CO2 on top. As you
heat the tank past 31C, the interface between the liquid and the gas
would start to shimmer & get diffuse. At 32C, the interface
disappears entirely. The fluid in the tank at that point is neither a
liquid or a gas, but exhibits properties of both.) It's an interesting
property of gasses/liquids, but it doesn't mean that your tank will
explode.

Look at the pressure rating of your tank, and when the gauge reads
close to that, then start to worry.

P.S. Supercritical CO2 is used in a bunch of industrial processes,
including drycleaning and coffee decaffination.


What about this safety valve I keep hearing about that sometimes blows
out in a hot car or room? I'm worried about that one. It sounds like a
jet taking off when it happens, apparently.

Nikki


Normally when they go off, it is in a clossed hot car or hot room, which
can be over 120 degrees F on a hot day and can even come close to 140
degrees F. If you can handle the temp the tank should be fine.

Kim

I use to transport CO2 cylinders in my car in Singapore where the temp is always in the the 30s, you will not have to worry about it.

In article ,
says...
Nikki Casali wrote:
Rocco Moretti wrote:

Nikki Casali wrote:

It's 31 degrees centigrade in my dining room where I keep my planted
aquarium. It's rather hot today! So at what temperature will my CO2
canister likely to "unload" its contents? According to the pressure
gauge, it's over 70 bar. I have just read that the critical
temperature is 31.6 degrees or 88.88 degrees F. Should I be worried?



I probably wouldn't worry about it much. CO2 cylinders are used for
fountain soda dispensers, and if we had them exploding whenever the
temperature got above 90F, we'd hear about it more often. (Soda
machine at a fair, outdoors on a summers day ...)

Also when a scientist talks about a "critical temperature" for a
substance, what that means is just that above the 32C temperature the
distinction between a liquid and a gas disappears. (At 70 atm and 25C,
CO2 is in it's liquid form. If you were able to see inside the tank,
you'd have liquid CO2 on the bottom, and gasseous CO2 on top. As you
heat the tank past 31C, the interface between the liquid and the gas
would start to shimmer & get diffuse. At 32C, the interface
disappears entirely. The fluid in the tank at that point is neither a
liquid or a gas, but exhibits properties of both.) It's an interesting
property of gasses/liquids, but it doesn't mean that your tank will
explode.

Look at the pressure rating of your tank, and when the gauge reads
close to that, then start to worry.

P.S. Supercritical CO2 is used in a bunch of industrial processes,
including drycleaning and coffee decaffination.


What about this safety valve I keep hearing about that sometimes blows
out in a hot car or room? I'm worried about that one. It sounds like a
jet taking off when it happens, apparently.

Nikki


Normally when they go off, it is in a clossed hot car or hot room, which
can be over 120 degrees F on a hot day and can even come close to 140
degrees F. If you can handle the temp the tank should be fine.

Kim

The MSDS (material data safety sheet) notes 125F or 52C as the max
storage temperature.

Link:
http://www.badgerfire.com/GetFile/F1...00379D03/Carbo
n%20Dioxide.pdf

DD

Alfred wrote:

I use to transport CO2 cylinders in my car in Singapore where the temp
is always in the the 30s, you will not have to worry about it.



OK. Thanks for alleviating my fears. I kept reading about tanks
spontaneously going off in vehicles. Must have been extreme temperatures
or left in the sun to bake.

Nikki

ddss wrote:

In article ,
says...

Nikki Casali wrote:

Rocco Moretti wrote:


Nikki Casali wrote:


It's 31 degrees centigrade in my dining room where I keep my planted
aquarium. It's rather hot today! So at what temperature will my CO2
canister likely to "unload" its contents? According to the pressure
gauge, it's over 70 bar. I have just read that the critical
temperature is 31.6 degrees or 88.88 degrees F. Should I be worried?



I probably wouldn't worry about it much. CO2 cylinders are used for
fountain soda dispensers, and if we had them exploding whenever the
temperature got above 90F, we'd hear about it more often. (Soda
machine at a fair, outdoors on a summers day ...)

Also when a scientist talks about a "critical temperature" for a
substance, what that means is just that above the 32C temperature the
distinction between a liquid and a gas disappears. (At 70 atm and 25C,
CO2 is in it's liquid form. If you were able to see inside the tank,
you'd have liquid CO2 on the bottom, and gasseous CO2 on top. As you
heat the tank past 31C, the interface between the liquid and the gas
would start to shimmer & get diffuse. At 32C, the interface
disappears entirely. The fluid in the tank at that point is neither a
liquid or a gas, but exhibits properties of both.) It's an interesting
property of gasses/liquids, but it doesn't mean that your tank will
explode.

Look at the pressure rating of your tank, and when the gauge reads
close to that, then start to worry.

P.S. Supercritical CO2 is used in a bunch of industrial processes,
including drycleaning and coffee decaffination.


What about this safety valve I keep hearing about that sometimes blows
out in a hot car or room? I'm worried about that one. It sounds like a
jet taking off when it happens, apparently.

Nikki


Normally when they go off, it is in a clossed hot car or hot room, which
can be over 120 degrees F on a hot day and can even come close to 140
degrees F. If you can handle the temp the tank should be fine.

Kim


The MSDS (material data safety sheet) notes 125F or 52C as the max
storage temperature.

Link:
http://www.badgerfire.com/GetFile/F1...00379D03/Carbo
n%20Dioxide.pdf

Great. That's just the link I needed.

Nikki

Nikki Casali wrote:
Alfred wrote:

I use to transport CO2 cylinders in my car in Singapore where the temp
is always in the the 30s, you will not have to worry about it.



OK. Thanks for alleviating my fears. I kept reading about tanks
spontaneously going off in vehicles. Must have been extreme temperatures
or left in the sun to bake.

Nikki

I believe DOT requires a high pressure blow-off mechanism for all gas
tanks transported in motor vehicles. The valves are usually one-use
pressure discs that pop and release the gas at a safe rate when exposed
to over pressure. My scuba cylinder has one.

--
Elaine T __
http://eethomp.com/fish.html '__
rec.aquaria.* FAQ http://faq.thekrib.com

I am not saying that the co2 tanks dont have a safety, just that in 30+C it's not a problem.