Compressing C02

[h.g.Whiz]

How much space would a theoretical bubble containing 100 miles of car exhaust take up at 1 atmosphere ?

[KingMerv00]

How much space would a theoretical bubble containing 100 miles of car exhaust take up at 1 atmosphere ?

How many cars over how much time?

[h.g.Whiz]

1 car for 1 hour

[Giggywig]

How much space would a theoretical bubble containing 100 miles of car exhaust take up at 1 atmosphere ?

What car?

[noreligion]

1 car for 1 hour

Wouldn't it also depend on what pressure you wanted? Also which state do you want the exhaust in and just to nitpick, are you asking about CO or CO2.

[John Jones]

Wouldn't it also depend on what pressure you wanted? Also which state do you want the exhaust in and just to nitpick, are you asking about CO or CO2.


He said 1 atm.

ETA: The subject line says CO2.

[KingMerv00]

1 car for 1 hour

One gallon of gas produces 20lbs of CO2: Link (http://www.cartalk.com/content/features/carbon/interview.html)

If the car runs at 25mpg, the car produces 80 lbs. of CO2 or 36,400 grams of carbon dioxide after driving 100 miles. The density (http://en.wikipedia.org/wiki/Carbon_dioxide) of CO2 is about 2 grams/liter at one atm at zero degrees C.

18,200 liters.

Picture 9,100 two liter Coke bottles. :D

[noreligion]

He said 1 atm.
Yes but is the 1 atm the full partial pressure of the gas he is looking for?
ETA: The subject line says CO2.
Yes it does. Do you have a problem with me wanting to be clear about it?

[jsfisher]

One gallon of gas produces 20lbs of CO2: Link (http://www.cartalk.com/content/features/carbon/interview.html)


I was getting ready to challenge this. It seemed a little high. After all, a gallon of gasoline weighs only about 6 lbs. Then I found this (http://www.fueleconomy.gov/feg/co2.shtml). I'll be quiet now.

[casebro]

Or, it makes a 20 pound block of dry ice.

[h.g.Whiz]

One gallon of gas produces 20lbs of CO2: Link (http://www.cartalk.com/content/features/carbon/interview.html)

If the car runs at 25mpg, the car produces 80 lbs. of CO2 or 36,400 grams of carbon dioxide after driving 100 miles. The density (http://en.wikipedia.org/wiki/Carbon_dioxide) of CO2 is about 2 grams/liter at one atm at zero degrees C.

18,200 liters.

Picture 9,100 two liter Coke bottles. :D

If I take these bottles down seven miles deep in the ocean , how much would they shrink ?

[KingMerv00]

Or, it makes a 20 pound block of dry ice.

The density (http://en.wikipedia.org/wiki/Carbon_dioxide) of CO2 is about 2 grams/liter at one atm at zero degrees C.

:D

[John Jones]

Yes but is the 1 atm the full partial pressure of the gas he is looking for?
Yes it does. Do you have a problem with me wanting to be clear about it?

Not at all, but the pressure and the gas in question seem perfectly clear.

[marplots]

One gallon of gas produces 20lbs of CO2: Link (http://www.cartalk.com/content/features/carbon/interview.html)

If the car runs at 25mpg, the car produces 80 lbs. of CO2 or 36,400 grams of carbon dioxide after driving 100 miles. The density (http://en.wikipedia.org/wiki/Carbon_dioxide) of CO2 is about 2 grams/liter at one atm at zero degrees C.

18,200 liters.

Picture 9,100 two liter Coke bottles. :D

Which brings up a more important question. How much CO2 is in 9,100 liter bottles of Coke? Full, unopened bottles, of course.

I will use this information to push my new, "second-hand carbon dioxide" agenda which seeks to protect young children from the hazards of CO2.

[John Jones]

STP

[noreligion]

Not at all, but the pressure and the gas in question seem perfectly clear.

Is CO2 the only gas in car exhaust that contains the chemicals C and O? If not, my question was nothing wrong and considering the subject asked about COMPRESSING a gas and 1 atm isn't exactly considered compression on Earth, nothing whatsoever was wrong with asking about pressure either.

[KingMerv00]

If I take these bottles down seven miles deep in the ocean , how much would they shrink ?

I am not familiar with the strength of Coke bottles but I will tell you they are very buoyant. How do you plan on sinking them?

[paiute]

Is CO2 the only gas in car exhaust that contains the chemicals C and O?

C and O are elements.

CO2 means carbon dioxide. CO is carbon monoxide.

We leave out 1s in formulas, as they are assumed. CO2 is the same as C1O2.

Carbon dioxide is O=C=O. There is no isomer of CO2 which has the structure O=O=C (outside of a laboratory vacuum manifold, maybe, certainly not in a car exhaust in any measurable amount).

So when the OP asked about CO2, there was no doubt about the compound in question.

[Loss Leader]

[quote=marplots;6074066]Which brings up a more important question. How much CO2 is in 9,100 liter bottles of Coke? Full, unopened bottles, of course.[quote]


IIRC, Coke presurizes its bottles to 3 gas volunes. So, there's 3 liters of CO2 in every liter of coke. (6 liters of CO2 in every 2 liter bottle.)

[KingMerv00]

Which brings up a more important question. How much CO2 is in 9,100 liter bottles of Coke? Full, unopened bottles, of course.

9,100 TWO liter bottles.

If Loss Leader is right, 9,100 two liter bottles hold 54,600 liters of CO2 at 1 atm at 0C.

Yes I know you are joking but I can't help myself.

[marplots]

2L? Oh my god. That's nearly twice as much.

[LTC8K6]

I was getting ready to challenge this. It seemed a little high. After all, a gallon of gasoline weighs only about 6 lbs. Then I found this (http://www.fueleconomy.gov/feg/co2.shtml). I'll be quiet now.

Burning a pound of jet fuel gets you 1.26 pounds of water vapor. :D

[casebro]

If I take these bottles down seven miles deep in the ocean , how much would they shrink ?


Lesee, the ocean at much depth is about 55F degrees. CO2 goes into solution at that temp at about 50 psi. Water pressure is about 1/2 psi/ft of depth, so pumping CO2 down only a hundred feet or so will push the gas into solution , carbonating the ocean. No need to bottle it, haul it to the Marianas trench, and dump it, just pump it off shore.

Then deal with the acidification of the seven seas, since in solution CO2 becomes Carbonic acid.

[Loss Leader]

carbonating the ocean.



That is literally the greatest plan I have ever heard.

[KingMerv00]

That is literally the greatest plan I have ever heard.

Humans stumbled onto that plan (http://earthobservatory.nasa.gov/Features/OceanCarbon/) by accident long ago.

[h.g.Whiz]

Lesee, the ocean at much depth is about 55F degrees. CO2 goes into solution at that temp at about 50 psi. Water pressure is about 1/2 psi/ft of depth, so pumping CO2 down only a hundred feet or so will push the gas into solution , carbonating the ocean. No need to bottle it, haul it to the Marianas trench, and dump it, just pump it off shore.

Then deal with the acidification of the seven seas, since in solution CO2 becomes Carbonic acid.


I don't want to dump it. I want to turn into dry ice.

[KingMerv00]

I don't want to dump it. I want to turn into dry ice.

Look at the phase diagram of CO2 (http://en.wikipedia.org/wiki/File:Carbon_dioxide_pressure-temperature_phase_diagram.svg). At one mile, the ocean pressure is about 160 atm (http://www.calctool.org/CALC/other/games/depth_press). At that pressure, the temperature must be less than -50 degrees C. The ocean gets nowhere near that cold (http://www.windows2universe.org/earth/Water/temp.html).

[Michael Redman]

I think you'll want to check this out: http://www.netl.doe.gov/publications/factsheets/project/Proj237.pdf

[noreligion]

C and O are elements.
You mean Carbon and Oxygen are not chemicals? Quick, send your proof to the international Nobel committee.

[Soapy Sam]

I take it the calculations above assume 100% conversion of fuel to exhaust gases?
How many cars achieve that?

[noreligion]

I take it the calculations above assume 100% conversion of fuel to exhaust gases?
How many cars achieve that?

The ones the oil companies are hiding :D

[casebro]

I take it the calculations above assume 100% conversion of fuel to exhaust gases?
How many cars achieve that?

According to my latest smog cert, only 1/10,000 of my exhaust is unburnt hydrocarbon.

[jasonpatterson]

OK, so it's clear that the only thing that the OP left out was the temperature at which he/she wanted this bubble's volume calculated, and it's reasonable to assume something like STP. It turns out that the question is fairly difficult to answer, since the engine will be taking in varying amounts of air, and the composition of that air is questionable (on a very humid day, for instance, air can contain a few percent of water vapor if it is very warm and humid, and that mucks up the calculations a good bit. I'll try to list any assumptions I make as I go along. Throughout, I am using sig figs. I also realize that I have an atmosphere that is about 102% composition, but the 2% error I'm introducing is well below the level of error in the values I've been able to find/that were a part of the question itself.

The car's exhaust, right at the tail pipe, is largely carbon dioxide, water, oxygen, nitrogen, argon, carbon monoxide, and nitrogen oxides.

Carbon dioxide: KingMerv gave a nice explanation of the amount of carbon dioxide that comes out of the engine, and that corresponds with the amount of oxygen that went in. I get about 18,500L when I do the calculation at STP.

Water: The 0.8 pounds of hydrogen in a gallon of gas get converted into 7.2 pounds of water. Since we're using 4 gallons, we've got about 30 pounds of water to deal with as well. At STP, the vast majority of this would have condensed, , but there would still be about 5 mmHg of water vapor present. This will contribute about 1/150th of the total exhaust volume, or about 1000L (based on later values.)

Oxygen: Some of the oxygen that went into the engine was never burned. I've had trouble finding out a precise number, but as best I can pin it down, a few percent of the volume of exhaust is oxygen in a modern car that is running properly. I'm going to make up a number and use it just to go on, if anyone has a better value, it should be fairly easy to substitute it in and tighten up the numbers. If 4% (my made up value, which is probably a bit high) of the exhaust is oxygen, then we can figure out how much that is by comparing it to the carbon dioxide and water that came out. For each mole of carbon dioxide that is produced, there was one of oxygen consumed. For each mole of water that is produced, there was one half of oxygen consumed. 18,500L of oxygen was converted into 18,500L of carbon dioxide, and 8,100L of oxygen was converted into about 16,200L of water vapor (of which the vast majority condensed.) Overall, about 26,600L of oxygen was consumed by the engine. Since the atmosphere is roughly 20% oxygen, and with my value 4/5ths of that oxygen are converted into carbon dioxide and water, the remaining oxygen in the exhaust should be 1/4th of the volume of the oxygen that was consumed, or about 7000L.

Nitrogen: The vast majority of nitrogen that goes into the engine leaves the engine unaffected. It makes up about 80% of the atmosphere, or 4 times as much as the total of oxygen consumed and exhausted, about 130,000L.

Argon: Argon is about 1% of the atmosphere, it's completely inert, and it takes up about 2000L both of intake and exhaust.

Carbon monoxide: This makes up about 0.1% of the exhaust of a car with a modern catalytic converter (at least according to what I've been able to find, wiki's and such.) That's about 200L.

Nitrogen oxides:
I can't find a reliable source for this value. All of the unreliable sources have it at less than 0.1% of the volume, another 200L or so.

Unburned hydrocarbons:
Casebro's post is my best source for this... At 0.01%, it's about 20L.

Total:
carbon dioxide + water vapor + oxygen + nitrogen + argon + carbon monoxide + nitrogen oxides + hydrocarbons = 18500 + 1000 + 7000 + 130000 + 2000 + 200 + 200 + 20 = 160,000L

Note: The vast majority of the volume of the exhaust is nitrogen, carbon dioxide, oxygen, argon, and water. With sig figs, the remaining components don't contribute anything above the level of error in the values.

I'd be shocked if I didn't mess up at least once in all this, so have at it.

ETA: 2 error found, turns out I can't divide by 5 or list a few compounds...

[casebro]

My smog report lists about .3% oxygen at 25 mph. Yes, that is a point three.

In the gas condensation business, the gasses are separated during the compression. A float valve in the soda bottles would let the liquified gas off the bottom of the bottle.

Of course, the bottle will crush to 1/12,000th of it's size. One drop of liquid co2 per bottle?

[jasonpatterson]

My smog report lists about .3% oxygen at 25 mph. Yes, that is a point three.

In the gas condensation business, the gasses are separated during the compression. A float valve in the soda bottles would let the liquified gas off the bottom of the bottle.

Of course, the bottle will crush to 1/12,000th of it's size. One drop of liquid co2 per bottle?

Wow, the car sites I found had people complaining about oxygen sensors reading 5%... I figured I'd pick 4% since it gave me pretty fractions; that'll teach me. :) Many thanks.

So my oxygen exhausted is about 10x too high, which means that my nitrogen is off as well. Figure 700L of oxygen, 110,000L of nitrogen, 1000L argon, 18,500 CO2, 1000 H2O vapor, 100L CO, 100L NOz, 10L hydrocarbons, 130,000 L total.

All told, the exhaust is about 15% CO2 by volume.

[KingMerv00]

Carbon dioxide: KingMerv gave a nice explanation of the amount of carbon dioxide that comes out of the engine, and that corresponds with the amount of oxygen that went in. I get about 18,500L when I do the calculation at STP.

Our slightly different results probably come from the fact that I rounded the density of CO2.

[h.g.Whiz]

Look at the phase diagram of CO2 (http://en.wikipedia.org/wiki/File:Carbon_dioxide_pressure-temperature_phase_diagram.svg). At one mile, the ocean pressure is about 160 atm (http://www.calctool.org/CALC/other/games/depth_press). At that pressure, the temperature must be less than -50 degrees C. The ocean gets nowhere near that cold (http://www.windows2universe.org/earth/Water/temp.html).


Releasing C02 from a cyllinder with pressure of 73 atmospheres makes dry ice right ?

[blutoski]

Releasing C02 from a cyllinder with pressure of 73 atmospheres makes dry ice right ?

Possibly for an instant.
It will be like snow and sublime as it mixes with air.

[Evilgiraffe]

Releasing C02 from a cyllinder with pressure of 73 atmospheres makes dry ice right ?

Yes, this is the Joule-Thomson effect (http://en.wikipedia.org/wiki/Joule%E2%80%93Thomson_effect). Allowing a gas to expand, reducing its pressure, reduces its temperature. This allows for the formation of solid dry ice from a cylinder of CO2. Weirdly, if the gas is hot enough before you reduce the pressure, allowing it to expand will make the gas hotter. This happens when a gas is above its Joule-Thomson inversion temperature.


Possibly for an instant.
It will be like snow and sublime as it mixes with air.

It can be done with one of these (http://www.google.co.uk/url?sa=t&source=web&cd=1&ved=0CBcQFjAA&url=http%3A%2F%2Fwww.uk.airliquide.com%2Ffile%2Fot herelement%2Fpj%2F10_2690snowpack21944.pdf&rct=j&q=snow+pack+co2&ei=p6YrTKayK4GoOJvdtbEJ&usg=AFQjCNFsxW9C9VBKVILCnbgyMCTYg7U9CQ) (PDF document). They make quite nice dry ice pellets if used with a nice full cylinder. They get a bit pathetic when the pressure starts to drop, as the Joule-Thomson cooling gets a bit weak.

[KingMerv00]

Releasing C02 from a cyllinder with pressure of 73 atmospheres makes dry ice right ?

Yes but that' not consistent with conditions at the bottom of the ocean.

[h.g.Whiz]

Maybe a balloon with the strength of graphene oxide paper would be necessary.

[Evilgiraffe]

Necessary for what?