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(WFAA Fort Worth)   Truck carrying liquid nitrogen overturns and crashes in Dallas. Driver gets out, resumes looking for Sarah Connor   (wfaa.com) divider line 94
    More: Scary, chemical tanker, fire trucks  
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6180 clicks; posted to Main » on 15 Jul 2013 at 8:25 PM (1 year ago)   |  Favorite    |   share:  Share on Twitter share via Email Share on Facebook   more»



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2013-07-15 09:52:59 PM
Liquid nitrogen can be compressed, or uncompressed. It is manufactured under pressure. If the pressure is reduced to one atmosphere, the boiling off of nitrogen will cool the remaining liquid nitrogen. Even in its unpressurized, cold state at 1 atmosphere, it can still be called compressed nitrogen, after its method of manufacture, particularly if you note the past tense of the word compressed, and of course, it is still under 1 atmosphere of pressure.
 
2013-07-15 09:55:45 PM

Greek: Compressed liquid nitrogen. Interesting, since liquids aren't compressible. it was liquid nitrogen, which is stored under pressure. But the liquid itself is not compressed.


It's probably bad terminology.  There's plenty of that in science.  The idea here is that nitrogen is stored and transported in its liquid form by being put under enough pressure that it becomes a liquid.  Therefore you don't need refrigerants or any of that crap, so liquid N2 is pretty easily available and cheap.  Heck, when I was in grad school we had giant doers of it sitting at room temperature all over the science and engineering departments.

And yes, you can compress liquids.  You simply have to put enough external force on its molecules that they overcome their repulsion to one another.
 
2013-07-15 10:00:41 PM
A black hole will compress just about anything you need compressed.
 
2013-07-15 10:04:18 PM

yet_another_wumpus: Kyosuke: Mentioned this to my chemist better-half, and all she said was "That's expensive."

Huh?  The only price I've ever heard said it was roughly (or cheaper) than milk.  HAZMAT is also a non issue since ,as buzzcut73 noted, N2 already makes up most of our atmosphere and will quickly boil away anyway.  Just keep everybody away from the low-O2 zone and wait.


That particular stretch is on a ridge, so there's no confinement issues.

I love that particular interchange because it is a ridge and the western view is impressive.
 
2013-07-15 10:12:49 PM

pion: Greek: Compressed liquid nitrogen. Interesting, since liquids aren't compressible. it was liquid nitrogen, which is stored under pressure. But the liquid itself is not compressed.

It's probably bad terminology.  There's plenty of that in science.  The idea here is that nitrogen is stored and transported in its liquid form by being put under enough pressure that it becomes a liquid.  Therefore you don't need refrigerants or any of that crap, so liquid N2 is pretty easily available and cheap.  Heck, when I was in grad school we had giant doers of it sitting at room temperature all over the science and engineering departments.

And yes, you can compress liquids.  You simply have to put enough external force on its molecules that they overcome their repulsion to one another.


The critical temp of Nitrogen is -232°F or -147°C.  While you may not need a refrigerant like ammonia, you still need to provide refrigeration to the plant to condense nitrogen.  Most times this is accomplished via a JT valve, expander, or another liquid (oxygen, etc) in a re-condenser.
 
2013-07-15 10:27:12 PM
You shouldn't use the term "compressed liquid nitrogen". That draws a parallel to propane or other room temperature liquid gasses. Liquid nitrogen is not held in it's liquid state by compression, it's held there by the temperature. It's endothermic evaporation helps keep the liquid that's still there cold. A relief valve has to be used to let the vapor pressure out, because you can't engineer a transportable container that could handle the pressure that would be generated if you warmed it to room temperature.
 
2013-07-15 11:02:31 PM

evaned: Sound travels through water. What carries it? Pressure waves.


Crap. We were both wrong, you're right.
 
2013-07-15 11:04:05 PM
Would have been cool if it collided with a truck carrying a huge toroid of yttrium barium copper oxide, and then a power line came down on it all.
 
2013-07-15 11:06:10 PM

JacksonBryan:
The critical temp of Nitrogen is -232°F or -147°C.  While you may not need a refrigerant like ammonia, you still need to provide refrigeration to the plant to condense nitrogen.  Most times this is accomplished via a JT valve, expander, or another liquid (oxygen, etc) in a re-condenser.

I will concede that I do not know how liquid nitrogen is manufactured, so I will defer to your knowledge.

I should have said:

pion: The idea here is that nitrogen is stored and transported in its liquid form by being put under enough pressure that it stays a liquid.


I shouldn't have said transported in a blanket statement, because I don't know how those tanker trucks operate.  And that, at least is accurate.
 
2013-07-15 11:06:46 PM
excellent headline
 
2013-07-15 11:16:52 PM

mamoru: chitownmike: Dimensio: skinink: I still like Terminator 2, but not so much since people kept asking, "Why didn't Skynet just send the Terminators to kill Sarah Connor when she was a kid, or kill her parents?

Skynet did not know which Sarah Connor was the mother of John Connor. It therefore could not have known where Ms. Connor lived during her childhood, nor would it be aware of the identity of her parents.

Yeah, there were no publicly available records in the 80's

Yup. This was all explained by Reese in the first movie.


This, and it was clear that the Terminator was just looking for Sarah Connors that lived in the area. Apparently your vaunted "permanent record" from school really was just kept in a paper file in the basement of the Department of Education, never to be scanned into .pdf file. Mostly because of the great Pedophile War of 1997.
 
2013-07-15 11:17:13 PM
Sources say several local musicians were inexplicably drawn to the scene, guitars in hand and REEEAAADDYYY TOOO ROCCCCKKKK! <insert screeching sound here>

//also lasers.
 
2013-07-15 11:18:50 PM

pion: JacksonBryan:
The critical temp of Nitrogen is -232°F or -147°C.  While you may not need a refrigerant like ammonia, you still need to provide refrigeration to the plant to condense nitrogen.  Most times this is accomplished via a JT valve, expander, or another liquid (oxygen, etc) in a re-condenser.

I will concede that I do not know how liquid nitrogen is manufactured, so I will defer to your knowledge.

I should have said:

pion: The idea here is that nitrogen is stored and transported in its liquid form by being put under enough pressure that it stays a liquid.

I shouldn't have said transported in a blanket statement, because I don't know how those tanker trucks operate.  And that, at least is accurate.


As JacksonBryan pointed out, the critical temperature is -147 Celsius. Above that temperature, there can be no state change between liquid and vapor. What you have above that temp is a highly compressed gas that looks like a liquid when under enough pressure, about 500 psi.
 
2013-07-15 11:29:47 PM

Bashar and Asma's Infinite Playlist: A black hole will compress just about anything you need compressed.


Sort of.  Actually from our point of view, time doesn't exist inside the black hole.  So things that fall into it are suspended in time at the event horizon.  One might ask, what happens after that.  But according to the math, there is no "after" that (from our perspective outside the hole), for anything that touches the event horizon.

Also, if you could look out while getting near the event horizon you would watch the surrounding stars and galaxies age, go dark and evaporate in heat death, as 10^100 years flashed by for you.  That always struck me as almost infinitely sad and lonely.
 
2013-07-15 11:35:24 PM

MarkEC: pion: JacksonBryan:
The critical temp of Nitrogen is -232°F or -147°C.  While you may not need a refrigerant like ammonia, you still need to provide refrigeration to the plant to condense nitrogen.  Most times this is accomplished via a JT valve, expander, or another liquid (oxygen, etc) in a re-condenser.

I will concede that I do not know how liquid nitrogen is manufactured, so I will defer to your knowledge.

I should have said:

pion: The idea here is that nitrogen is stored and transported in its liquid form by being put under enough pressure that it stays a liquid.

I shouldn't have said transported in a blanket statement, because I don't know how those tanker trucks operate.  And that, at least is accurate.

As JacksonBryan pointed out, the critical temperature is -147 Celsius. Above that temperature, there can be no state change between liquid and vapor. What you have above that temp is a highly compressed gas that looks like a liquid when under enough pressure, about 500 psi.


Pressure affects the temperature at which the phase changes.  The phase diagram has 2 axes: pressure and temperature.  That is why water boils at lower temperatures in Denver than it does in Jacksonville.   The boiling point of LN2 is not -147 C; it is 77K, which corresponds to -196K.
 
2013-07-15 11:36:09 PM

pion: The boiling point of LN2 is not -147 C; it is 77K, which corresponds to -196 C.


FTFM
 
2013-07-15 11:38:19 PM

pion: JacksonBryan:
The critical temp of Nitrogen is -232°F or -147°C.  While you may not need a refrigerant like ammonia, you still need to provide refrigeration to the plant to condense nitrogen.  Most times this is accomplished via a JT valve, expander, or another liquid (oxygen, etc) in a re-condenser.

I will concede that I do not know how liquid nitrogen is manufactured, so I will defer to your knowledge.

I should have said:

pion: The idea here is that nitrogen is stored and transported in its liquid form by being put under enough pressure that it stays a liquid.

I shouldn't have said transported in a blanket statement, because I don't know how those tanker trucks operate.  And that, at least is accurate.


Those tanks are actually tanks within a tank.  They are separated by an annular space that has a vacuum pulled on it to keep the tank insulated and cold.  The pressure does not keep the liquid, the fact that there is very little heat leak keeps the liquid a liquid.  As mentioned above, there is a road-relief valve that maintains the pressure below the DOT regulated limit for that product which if memory serves is 27 psig (might not be 100% correct)

The better the vacuum on the trailer, the lower the losses. 

It is true that a higher pressure means a warmer temperature to turn the gas to a liquid but the trailer pressure fluctuates depending on the trailer.
 
2013-07-15 11:41:17 PM

pion: pion: The boiling point of LN2 is not -147 C; it is 77K, which corresponds to -196 C.

FTFM


Correct, but the critical temperature of LIN is -147°C.  That means, no matter what the pressure is raised too, unless it is colder than -147° it will not boil.  This is why the early attempts at creating a liquid at extremely high pressures failed.
 
2013-07-15 11:48:22 PM

JacksonBryan: pion: pion: The boiling point of LN2 is not -147 C; it is 77K, which corresponds to -196 C.

FTFM

Correct, but the critical temperature of LIN is -147°C.  That means, no matter what the pressure is raised too, unless it is colder than -147° it will not boil.  This is why the early attempts at creating a liquid at extremely high pressures failed.


Here, I found a site that has a pretty good explanation of critical temperature.
 
2013-07-15 11:51:48 PM

ThrobblefootSpectre: Also, if you could look out while getting near the event horizon you would watch the surrounding stars and galaxies age, go dark and evaporate in heat death, as 10^100 years flashed by for you. That always struck me as almost infinitely sad and lonely.


Yes, except that 10^100 years worth of starlight compressed into such a brief interval would be blue-shifted to the extreme end of the gamma spectrum and would incinerate you before you had a chance to experience any emotions.
 
2013-07-16 12:02:57 AM

ThrobblefootSpectre: Would have been cool if it collided with a truck carrying a huge toroid of yttrium barium copper oxide, and then a power line came down on it all.


Lol... An HVDC line hopefully (which are relatively uncommon at least in the US)
 
2013-07-16 12:04:18 AM

MarkEC: Here, I found a site that has a pretty good explanation of critical temperature.


Xenon also makes a nice demo. Its critical temperature is about 16C so you can liquify it in the refrigerator and then watch it go supercritical as it warms up to room temperature.
 
2013-07-16 12:22:20 AM

Ivo Shandor: Yes, except that 10^100 years worth of starlight compressed into such a brief interval would be blue-shifted to the extreme end of the gamma spectrum and would incinerate you before you had a chance to experience any emotions.


I didn't fall into the black hole.  I experienced the emotion while thinking about it from the outside.

But yes, even ignoring that "you" would already be converted to quarks and gluon radiation anyway, (which is why I said if), you wouldn't get meaningful information from the rest of the radiation near the event horizon with you.
 
2013-07-16 12:49:56 AM

ThrobblefootSpectre: Actually from our point of view, time doesn't exist inside the black hole.


Unless you consider the current universe to be already inside a black hole.
 
2013-07-16 01:11:51 AM
If only it could have collided with a tanker truck full of creme anglaise. Free super-premium vanilla ice cream for everyone!
 
2013-07-16 01:14:17 AM

ThrobblefootSpectre: Ivo Shandor: Yes, except that 10^100 years worth of starlight compressed into such a brief interval would be blue-shifted to the extreme end of the gamma spectrum and would incinerate you before you had a chance to experience any emotions.

I didn't fall into the black hole.  I experienced the emotion while thinking about it from the outside.

But yes, even ignoring that "you" would already be converted to quarks and gluon radiation anyway, (which is why I said if), you wouldn't get meaningful information from the rest of the radiation near the event horizon with you.


Not to mention the tidal forces that would shred your fleshy meat body before that - and that's assuming there's no other matter such as gas clouds being pulled in at the same time. The massive forces around a black hole make that stuff incredibly hot too.
 
2013-07-16 04:52:38 AM

Greek: Compressed liquid nitrogen. Interesting, since liquids aren't compressible. it was liquid nitrogen, which is stored under pressure. But the liquid itself is not compressed.


The gas is compressed into a liquid. And by the way, liquids are compressible, just not very much.
 
2013-07-16 05:03:04 AM

MarkEC: You shouldn't use the term "compressed liquid nitrogen". That draws a parallel to propane or other room temperature liquid gasses. Liquid nitrogen is not held in it's liquid state by compression, it's held there by the temperature. It's endothermic evaporation helps keep the liquid that's still there cold. A relief valve has to be used to let the vapor pressure out, because you can't engineer a transportable container that could handle the pressure that would be generated if you warmed it to room temperature.


It's considered "compressed" for that reason - it's a safety thing, and that terminology is required by law, OSHA, and probably the EPA as well.
 
2013-07-16 06:25:32 AM

JacksonBryan: Those tanks are actually tanks within a tank.


defsounds.com
 
2013-07-16 06:37:38 AM
That movie was 12 farking years ago.. Time to retire that stupid meme.
 
2013-07-16 09:34:09 AM

iron de havilland: JacksonBryan: Those tanks are actually tanks within a tank.

[defsounds.com image 741x487]


Did it confuse you?  The wording is unique, I guess I could have said you have an inner vessel and outer vessel.
 
2013-07-16 10:04:56 AM

buzzcut73: That was always a favorite trick question of mine when I was teaching HAZMAT response to volunteer firefighters and other people that may come into contact with transportation accidents. How to handle the liquid Nitrogen spill with a broken valve that could not be operated to shut off the leak.

/Stay away from it and let it go. Nitrogen is 78% of our atmosphere and will just freeze the ground is the correct answer. Nothing complex required.


How far do you have to stay back for the asphyxiation threat, though?
 
2013-07-16 10:36:19 AM

abhorrent1: That movie was 12 farking years ago.. Time to retire that stupid meme.


Cool, I'm just out of college again.  Math: not even once.
 
2013-07-16 11:15:48 AM

calbert: [www.gonemovies.com image 800x340]

/obscure?


What movie is that from?


/of course I know what movie that's from
/Jurassic Park
 
2013-07-16 11:43:30 AM

Loren: buzzcut73: That was always a favorite trick question of mine when I was teaching HAZMAT response to volunteer firefighters and other people that may come into contact with transportation accidents. How to handle the liquid Nitrogen spill with a broken valve that could not be operated to shut off the leak.

/Stay away from it and let it go. Nitrogen is 78% of our atmosphere and will just freeze the ground is the correct answer. Nothing complex required.

How far do you have to stay back for the asphyxiation threat, though?


A LIN trailer holds roughly 650,000 scf of LIN.  1 SCF LIN expands to 800 scf of gas if I remember my calculation correctly.  So I would recommend staying out of the vapor cloud and upwind of the spill.  The problem is low lying areas, not so much out in the open.
 
2013-07-16 11:44:40 AM

calbert: [www.gonemovies.com image 800x340]

/obscure?


Do have the original of that?
 
2013-07-16 12:18:54 PM
An overhead shot of the two air separation units I manage. 

i39.tinypic.com
 
jrl
2013-07-16 03:26:58 PM

JacksonBryan: An overhead shot of the two air separation units I manage.

[i39.tinypic.com image 819x639]


Pretty cool. Are the two gray cylinders in the middle the cryo stills?
 
2013-07-16 03:37:33 PM

jrl: JacksonBryan: An overhead shot of the two air separation units I manage.

[i39.tinypic.com image 819x639]

Pretty cool. Are the two gray cylinders in the middle the cryo stills?


It's hard to see the cold boxes from that view but the picture below shows the distillation columns "Cold Box".

i39.tinypic.com
 
2013-07-16 06:50:17 PM

Zafler: abhorrent1: That movie was 12 farking years ago.. Time to retire that stupid meme.

Cool, I'm just out of college again.  Math: not even once.


Yes. 22 years. Typo
 
2013-07-16 08:05:00 PM

abhorrent1: That movie was 12 farking years ago.. Time to retire that stupid meme.


Surely you can't be serious.
 
2013-07-16 11:08:32 PM

skinink: I still like Terminator 2, but not so much since people kept asking, "Why didn't Skynet just send the Terminators to kill Sarah Connor when she was a kid, or kill her parents?


They may have been working on that, but the humans captured the time transmitter after the second unit was dispatched.
 
2013-07-17 12:23:19 AM

JacksonBryan: iron de havilland: JacksonBryan: Those tanks are actually tanks within a tank.

[defsounds.com image 741x487]

Did it confuse you?  The wording is unique, I guess I could have said you have an inner vessel and outer vessel.


Based on the meme, I think he was making a joke. I usually describe a Dewar as a glorified thermos.
 
2013-07-17 03:08:11 AM

chitownmike: Dimensio: skinink: I still like Terminator 2, but not so much since people kept asking, "Why didn't Skynet just send the Terminators to kill Sarah Connor when she was a kid, or kill her parents?

Skynet did not know which Sarah Connor was the mother of John Connor. It therefore could not have known where Ms. Connor lived during her childhood, nor would it be aware of the identity of her parents.

Yeah, there were no publicly available records in the 80's



 SILBERMAN
     (recorded)
Why were the other two women killed?
          REESE
     (recorded)
Most official records were lost in the war.  The computer knew almost nothing about Connor's mother.  Her name.  Where she lived, just the city.  No scanner pictures.  The Terminator was just being systematic.
 
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