Why CO2?

[Septic343]

I was thinking about this the other day and i was wondering...

why do the pneumatic flippers use CO2 gas? Is it because you can get more force out of it than other gases or something? I'm not really an expert on these sorts of things.

[typhoon_driver]

At 1000psi it is a liquid and so is easier to store in a compressed form. Nitrogen needs a higher pressure I believe

[Liftoff]

Thats right, liquid nitrogen is more in the range of 10000psi .... imagine the weight of a tank able to contain that!

[Flag Captured]

I'd assume that, derivative of that, it's the safety too in case one of them gets a puncture - I'm no expert but if Liquid CO2 is 1000 psi and Liquid Nitrogen is 10,000 psi, the latter's going to go with a significantly larger bang...

[typhoon_driver]

http://blogs.howstuffworks.com/2009/...quid-nitrogen/

Nitrogen won't liquefy at any pressure at room temperature

[psychostorm]

Best energy density changing from liquid to gas, easier to engineer, cheap to replace, not flammable & not a greenhouse gas.

[maddox10]

Main reason why CO2 is used is the FRA rules. We are not allowed to go over 1000psi/70 bar for pneumatics.
CO2 or air, all the rest of the inert gasses like Nitrogen ain't allowed since a few years. This to avoid event organisers having to set up a tankpark with any kind of inert gas available. Even with people bringing their own refill bottle.

A tad of further explanation.

Stored CO2 is expressed in mass (kg), as most other gasses are expressed in volume (liters).

1 Kg of CO2 is 512 liters of gas at room temperature and pressure. A 2 kg CO2 bottle has a volume of 3 liters. Therefore, there is 1024 liters of gas in that bottle.

With nitrogen/air/helium that same bottle can hold 210 liters of gas @70 bar. And even @200 bar it's "only" 600 liters.

I believe CO2 wins in storage capacity...

[maddox10]

Best energy density changing from liquid to gas, easier to engineer, cheap to replace, not flammable & not a greenhouse gas.

Oh, CO2 not a greenhouse gas?

[leorcc]

not a greenhouse gas.

Lolwhut?

[Septic343]

Thanks Guys

[psychostorm]

Oh, CO2 not a greenhouse gas?

I'm thinking of Ozone Depleting Substances. CO2 doesn't deplete Ozone.

It's been a few years since since I studied the greenhouse effect. Apparently, we're all screwed anyway so I try not to think about it.

[Garfie489]

It doesnt contribute to the greenhouse effect, because stored CO2 generally was originally CO2 in the atmosphere to begin with.

The greenhouse effect is caused by turning compounds into CO2 (partially). Turning Liquid CO2 into Gas CO2 has no net greenhouse effect, although if we was to leave it in the tanks it would help the atmosphere by having a net reduction in CO2

[maddox10]

It doesnt contribute to the greenhouse effect, because stored CO2 generally was originally CO2 in the atmosphere to begin with.

The greenhouse effect is caused by turning compounds into CO2 (partially). Turning Liquid CO2 into Gas CO2 has no net greenhouse effect, although if we was to leave it in the tanks it would help the atmosphere by having a net reduction in CO2

So, if CO2 isn't contributing to the greenhouse effect of the atmosphere, why are all the greenies so riled up about it ?

[Garfie489]

Because we are turning things which are not CO2, into CO2.

For example, Hydrocarbons. The smallest Hydrocarbon is the Alkane called Methane. Its formula is CH4. When we add oxygen to it, and burn we get this equation.

CH4 + 2O2 = CO2 + 2H20 (ie 1 mole of methane, added to 2 moles of Oxygen produces a mole of Carbon dioxide, and two moles of Dihydrogen Monoxide)

Carbon dioxide does not exist before, however it exists after. Causing a net increase in CO2 in the atmosphere.

When we use Carbon Dioxide, there is no creation or destruction of CO2, because there is no reaction. Its simply a change of state.

[Anttazz]

The CO2 that we use isn't extracted from the air, it's created and pressurise so it is adding to the greenhouse effect. I think it's done using Calcium Carbonate and acid/water or similar then pressurised to ensure purity, something like that anyway.

But still, it's a small drop in the ocean compared to other things that are spewing out nasty gases.