Dry Ice Box?
 

I have routinely taken a half gallon of ice cream on our Kayak
excursions. It is inside a smaller lunchbox size cooler with about 5
lbs of dryice on top, and that cooler placed inside another cooler.
Works great. The only problem has been that the ice cream was sometimes
still frozen (after 3 days) too rock hard to dispense. It hat to sit
out for thirty minutes to get a scoop in it.

I doubt it's advantageous to use dry ice for a longer cooler duration.
Three days seems to be the maximum. But if you want to keep things
frozen, it's perfect. It's available around here in any local grocery
store, from a special "Dry Ice" freezer by the entrance.

Dry Ice Box?
 

On Mon, 03 Jul 2006 16:55:28 -0700, Keith Hughes
wrote:

Brian Whatcott wrote:


Nitrogen displaces oxygen, so you pass out without warning.

Nitrogen does not *displace* oxygen (O2 weighs more than N2).
//

Keith Hughes

This sort of technical thread too easily turns into a ****ing contest,
I realise.
So when I say nitrogen displaces oxygen, do tell me what happens when
I introduce a nitrogen generator of 300 cu ft /min into a closed room
of 1000 cu ft.
The nitrogen displaces the room atmosphere does it not?
(Whether the prior atmosphere in question is all oxygen, all hydrogen,
all helium, all whatever...)


OK?

Brian Whatcott Altus OK

Dry Ice Box?
 

On Mon, 03 Jul 2006 20:20:36 -0400, Sailaway
wrote:

Brian Whatcott wrote:
Nitrogen displaces oxygen, so you pass out without warning.


Material Safety Data Sheet
Gaseous Nitrogen:

SIMPLE ASPHYXIANT
Section 3 : HAZARD IDENTIFICATION
Emergency Overview:

Inhalation:
May cause dizziness.
Asphyxiant.
Can cause vomiting.
May result in unconsciousness.
May cause excitation, excess salivation, rapid breathing.
May cause headaches and drowsiness.
May cause stinging of the nose and throat.


So maybe lots of warning before passing out. But like others have said,
it only happens at extreme concentrations.


Though your MSDS cites supported a point of mine previously, I try to
recall that MSDS are heavily contaminated with lawyer inputs.
I have seen the baro chamber tests that I find more convincing.

Brian Whatcott Altus OK

Dry Ice Box?
 

Brian Whatcott wrote:
On Mon, 03 Jul 2006 16:55:28 -0700, Keith Hughes
wrote:


Brian Whatcott wrote:



Nitrogen displaces oxygen, so you pass out without warning.

Nitrogen does not *displace* oxygen (O2 weighs more than N2).

//

Keith Hughes


This sort of technical thread too easily turns into a ****ing contest,
I realise.
So when I say nitrogen displaces oxygen, do tell me what happens when
I introduce a nitrogen generator of 300 cu ft /min into a closed room
of 1000 cu ft.
The nitrogen displaces the room atmosphere does it not?
(Whether the prior atmosphere in question is all oxygen, all hydrogen,
all helium, all whatever...)

No, it does not. In a "closed room", you would merely be pressurizing
the room, and reducing the partial pressures of whatever gases were
there to begin with. If the room is vented, then it would depend on the
relative densities of the N2 and the original gases, and the
configuration of the inlet and the exhaust vents. I do these types of
studies all the time in cleanrooms, autoclaves, EtO chambers, and
purging and overlaying containers with N2, and they are not simple
processes.

And let's put your scenario in the context of the discussion, 300
ft3/min of CO2 would require sublimation of 5400 lbs/minute.



OK?

My point was that, unlike say, propane, adding Nitrogen to air gradually
dilutes the O2 content. It doesn't displace it like a heavier gas would,
where, rather suddenly, you'd be submerged in a blanket layer. The
result is a gradual diminution of O2 that the body will detect, and
respond to. The response is increased respiration, which will work
until the O2 gets below about 10%.

And unlike your generator scenario, where you simply pressurize a
vessel, or flush a vessel designed for purging, the "generator" in real
life is very, very small, and boats are not sealed.

I'm not trying to win a ****ing contest, but let's remember that the
response to the OP was, to paraphrase 'do it and you'll die', which was
singularly unhelpful, and inaccurate relative to the question of using
reasonable quantities of dry ice in a cooler, in a typically vented
boat. I'm trying to point out that it can be done, and done safely, as
long as reasonable care is taken.

Keith Hughes

Dry Ice Box?
 

Brian Whatcott wrote:

snip

Though your MSDS cites supported a point of mine previously, I try to
recall that MSDS are heavily contaminated with lawyer inputs.
I have seen the baro chamber tests that I find more convincing.

Brian Whatcott Altus OK

I've been personally involved in some MSDS generation processes (needed
for cleaning validation of pharmaceutical processes), and I can tell you
from experience that lawyer inputs are probably one of the lesser
contaminants in the process. OSHA doesn't generate these things, the
folks making the chemicals do. Not suggesting anything nefarious, just
noting that some of these folks, IME, don't have all their dogs barking.

Keith Hughes

Dry Ice Box?
 

On Wed, 05 Jul 2006 09:19:03 -0700, Keith Hughes
wrote:

I'm trying to point out that it can be done, and done safely, as
long as reasonable care is taken.

And it *has* been done for many years by myself and others with no
problems whatsoever. The only real hazzard is touching the dry ice
with bare skin but that is easily avoided.

Dry Ice Box?
 

I am going to do an engineering guess and say that the density of CO2 gas at
room temperature is 0.11 #/ft. So for 300 ft/min it works out to 33# per
minute. Now that's a lot of dry ice subliming but something less then 5400
# per minute.


"Keith Hughes" wrote in message
...

Brian Whatcott wrote:
On Mon, 03 Jul 2006 16:55:28 -0700, Keith Hughes
wrote:


Brian Whatcott wrote:



Nitrogen displaces oxygen, so you pass out without warning.

Nitrogen does not *displace* oxygen (O2 weighs more than N2).

//

Keith Hughes


This sort of technical thread too easily turns into a ****ing contest,
I realise.
So when I say nitrogen displaces oxygen, do tell me what happens when
I introduce a nitrogen generator of 300 cu ft /min into a closed room
of 1000 cu ft.
The nitrogen displaces the room atmosphere does it not?
(Whether the prior atmosphere in question is all oxygen, all hydrogen,
all helium, all whatever...)

No, it does not. In a "closed room", you would merely be pressurizing the
room, and reducing the partial pressures of whatever gases were there to
begin with. If the room is vented, then it would depend on the relative
densities of the N2 and the original gases, and the configuration of the
inlet and the exhaust vents. I do these types of studies all the time in
cleanrooms, autoclaves, EtO chambers, and purging and overlaying
containers with N2, and they are not simple processes.

And let's put your scenario in the context of the discussion, 300 ft3/min
of CO2 would require sublimation of 5400 lbs/minute.



OK?

My point was that, unlike say, propane, adding Nitrogen to air gradually
dilutes the O2 content. It doesn't displace it like a heavier gas would,
where, rather suddenly, you'd be submerged in a blanket layer. The result
is a gradual diminution of O2 that the body will detect, and respond to.
The response is increased respiration, which will work until the O2 gets
below about 10%.

And unlike your generator scenario, where you simply pressurize a vessel,
or flush a vessel designed for purging, the "generator" in real life is
very, very small, and boats are not sealed.

I'm not trying to win a ****ing contest, but let's remember that the
response to the OP was, to paraphrase 'do it and you'll die', which was
singularly unhelpful, and inaccurate relative to the question of using
reasonable quantities of dry ice in a cooler, in a typically vented boat.
I'm trying to point out that it can be done, and done safely, as long as
reasonable care is taken.

Keith Hughes

Dry Ice Box?
 

Hmmm....brainfart. 1 Lb of dry ice sublimes to 250L of CO2 gas, or
about 8.8 ft^3. So, 300 ft^3/min would requie about 34 Lbs/minute.
That's still a lot of dry ice :-)

Keith Hughes

Rick wrote:
I am going to do an engineering guess and say that the density of CO2 gas at
room temperature is 0.11 #/ft. So for 300 ft/min it works out to 33# per
minute. Now that's a lot of dry ice subliming but something less then 5400
# per minute.


"Keith Hughes" wrote in message
...

Brian Whatcott wrote:

On Mon, 03 Jul 2006 16:55:28 -0700, Keith Hughes
wrote:



Brian Whatcott wrote:




Nitrogen displaces oxygen, so you pass out without warning.

Nitrogen does not *displace* oxygen (O2 weighs more than N2).

//


Keith Hughes


This sort of technical thread too easily turns into a ****ing contest,
I realise.
So when I say nitrogen displaces oxygen, do tell me what happens when
I introduce a nitrogen generator of 300 cu ft /min into a closed room
of 1000 cu ft.
The nitrogen displaces the room atmosphere does it not?
(Whether the prior atmosphere in question is all oxygen, all hydrogen,
all helium, all whatever...)

No, it does not. In a "closed room", you would merely be pressurizing the
room, and reducing the partial pressures of whatever gases were there to
begin with. If the room is vented, then it would depend on the relative
densities of the N2 and the original gases, and the configuration of the
inlet and the exhaust vents. I do these types of studies all the time in
cleanrooms, autoclaves, EtO chambers, and purging and overlaying
containers with N2, and they are not simple processes.

And let's put your scenario in the context of the discussion, 300 ft3/min
of CO2 would require sublimation of 5400 lbs/minute.



OK?

My point was that, unlike say, propane, adding Nitrogen to air gradually
dilutes the O2 content. It doesn't displace it like a heavier gas would,
where, rather suddenly, you'd be submerged in a blanket layer. The result
is a gradual diminution of O2 that the body will detect, and respond to.
The response is increased respiration, which will work until the O2 gets
below about 10%.

And unlike your generator scenario, where you simply pressurize a vessel,
or flush a vessel designed for purging, the "generator" in real life is
very, very small, and boats are not sealed.

I'm not trying to win a ****ing contest, but let's remember that the
response to the OP was, to paraphrase 'do it and you'll die', which was
singularly unhelpful, and inaccurate relative to the question of using
reasonable quantities of dry ice in a cooler, in a typically vented boat.
I'm trying to point out that it can be done, and done safely, as long as
reasonable care is taken.

Keith Hughes

Dry Ice Box?
 

There in lays the futility of this debate. A 24x18X18 cooler with a typical
R value of 7 and an internal temperature of 0F in an 80F cabin will gain
about 190 BTUs per hour which will melt about 3/4 pound of dry ice to form
about 6 cu.ft of CO2.

Unless you are sleeping on the floor right next to the cooler in a sealed up
cabin there is not a lot of danger.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Keith Hughes" wrote in message
...
Hmmm....brainfart. 1 Lb of dry ice sublimes to 250L of CO2 gas, or about
8.8 ft^3. So, 300 ft^3/min would requie about 34 Lbs/minute. That's still
a lot of dry ice :-)

Keith Hughes

Rick wrote:
I am going to do an engineering guess and say that the density of CO2 gas
at room temperature is 0.11 #/ft. So for 300 ft/min it works out to 33#
per minute. Now that's a lot of dry ice subliming but something less
then 5400 # per minute.


"Keith Hughes" wrote in message
...

Brian Whatcott wrote:

On Mon, 03 Jul 2006 16:55:28 -0700, Keith Hughes
wrote:



Brian Whatcott wrote:




Nitrogen displaces oxygen, so you pass out without warning.

Nitrogen does not *displace* oxygen (O2 weighs more than N2).

//


Keith Hughes


This sort of technical thread too easily turns into a ****ing contest,
I realise.
So when I say nitrogen displaces oxygen, do tell me what happens when
I introduce a nitrogen generator of 300 cu ft /min into a closed room
of 1000 cu ft.
The nitrogen displaces the room atmosphere does it not?
(Whether the prior atmosphere in question is all oxygen, all hydrogen,
all helium, all whatever...)

No, it does not. In a "closed room", you would merely be pressurizing
the room, and reducing the partial pressures of whatever gases were there
to begin with. If the room is vented, then it would depend on the
relative densities of the N2 and the original gases, and the
configuration of the inlet and the exhaust vents. I do these types of
studies all the time in cleanrooms, autoclaves, EtO chambers, and purging
and overlaying containers with N2, and they are not simple processes.

And let's put your scenario in the context of the discussion, 300 ft3/min
of CO2 would require sublimation of 5400 lbs/minute.



OK?

My point was that, unlike say, propane, adding Nitrogen to air gradually
dilutes the O2 content. It doesn't displace it like a heavier gas would,
where, rather suddenly, you'd be submerged in a blanket layer. The
result is a gradual diminution of O2 that the body will detect, and
respond to. The response is increased respiration, which will work until
the O2 gets below about 10%.

And unlike your generator scenario, where you simply pressurize a vessel,
or flush a vessel designed for purging, the "generator" in real life is
very, very small, and boats are not sealed.

I'm not trying to win a ****ing contest, but let's remember that the
response to the OP was, to paraphrase 'do it and you'll die', which was
singularly unhelpful, and inaccurate relative to the question of using
reasonable quantities of dry ice in a cooler, in a typically vented boat.
I'm trying to point out that it can be done, and done safely, as long as
reasonable care is taken.

Keith Hughes

Dry Ice Box?
 

Brian Whatcott wrote:

On Sat, 01 Jul 2006 04:29:08 GMT, cavelamb
wrote:


Anyone out there use dry ice for refrigeration?

I want to keep the cooler cooler longer.


A couple pounds of dry ice seems like a good idea,
but how to use it?

Mix with wet ice?

Or keep separate?

Richard


The CO2 evolved from dry ice is too cold for chilling food and drinks
directly, but it can keep the water ice from melting so quickly.
This suggests a cooler within a cooler - the inner cooler giving
off CO2 gas which bubbles through a water ice mixture, which chills
the food container.

Dry ice provides a tidy explosion if its vapor has nowhere to go, and
it is not a good breathing gas - but at least it gives plenty of
warning - we are designed to pant if the CO2 proportion rises
(unlike low O2 which induces unconsciousness with no warning at all.)

You might take a look at the electric cooler boxes. Either way,
expanded polystyrene is an excellent insulation.

Brian Whatcott Altus OK

Well, I asked, didn't I.

Thanks to all for the information.

As it worked out a couple or three pounds of dry ice in one corner of the
ice chest kept the rest of the wet ice well frozen for three days. (!)

I think the wet ice is acting as insulation to protect the food stuff from
the dry ice - depending on how close stuff is to the dry stuff.

My boat is an 18 foot Capri (Catalina) so we don't have a lot of room to
play with. But with the companionway open at all there doesn't seem to be
much danger from CO2. There is just not enough dry ice in the box to make
much CO2 very rapidly (as was pointed out several times).

BUT! It really does keep the cooler cooler longer...

Thanks folks,

Richard