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Automotive Some ideas for a CO2 emission reduction device to be attached to cars

  1. Aug 23, 2012 #1

    I and my team-mate have proposed an idea to develop a CO2 emission reduction device to be installed in automobiles.

    We have mentioned that it will operate on the principle of 'active adsorption of CO2 on charcoal'.

    However, although the basic scientific principle is pretty simple, we haveno idea of how to develop on this idea and come out with an idea to actually implement this idea: including how it will look (design), where it will be attached, how economic it will be etc.

    Please give me some idea of what to do about it or give me some papers/links that are relevant.

  2. jcsd
  3. Aug 23, 2012 #2
    Some questions:
    1. where's the energy to compress the CO2 come from? As not much of anything will be adsorbed by simply passing the exhaust through (activated) carbon.
    2. how much charcoal will you need to store a useful amount of CO2? And how much will room does it need/how much does it weigh?
    3. once you have all this adsorbed CO2, what do you suggest doing with it? - You could bury the charcoal, Terra-preta style; but you would probably offset more atmospheric-CO2 by running the vehicle as efficiently as possible and 'digging-in' a little extra char.

    If this is along the lines of a coal-fired power station, fitted with Carbon Capture & Storage then be aware that the economies of scale on a car are far too small to still have an energy 'overhead' to power such a process. IMO, it's a fairly dire idea on a huge power-plant, but it's really, unimaginably bad on a small automobile.

    My apologies, though, if I've completely got the wrong end of the stick with this.
  4. Sep 6, 2012 #3
    Hi rethunk,

    THanks a lot for your critical review, it made us look into the matter a lot deeper :-)

    We looked into the details you mentioned and it seems that we'll not need an awful lot of activated charcoal for the purpose. We've also looked up on some possible uses of the adsorbant after the whole thing is over.

    Finally, we made a design, the picture of which I'm attaching here.
    One question is that we want to increase the pressure of the exhaust gases so that the adsorption rates can be increased. Since decreasing the velocity will lead to an increase in pressure, we were planning to add an air/water bladder which will expand as the air flows in thereby compressing the in-flowing gases.

    Also, in case its easier for you to understand, I'll just mention that basically the exhaust gas is made to fall on the activated charcoal (adsorbant) and it loses its momentum upon colliding with the adsorbant (which is put vertically to increase momentum loss). We've put a nozzle to restrict the flow of the gases.

    Thanks a lot!


    Attached Files:

  5. Sep 6, 2012 #4
    Two things spring to mind.

    1. An exhaust is designed to get rid of the gases (obvious, I know but bear with me ;)). This is adding what sounds like a very large restriction on that, and in general everything i the exhause is designed to reduce the flow restriction to prevent back pressure.

    2. The average fleet car puts out 120g CO2/ km. Even if this becomes a service item, 10k km. The amount of CO2 thoughput is 1200kg.

    Realisitically what proportion do you expect to capture?

    Just some food for thought.
  6. Sep 6, 2012 #5


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    I once had a catalytic converter fail and block the exhaust system with the debris.

    That was a VERY effective way to reduce CO2 emissions. The engine would not run at all, except at idle speed with no load. That wasn't very useful for transportation, but it didn't generate much pollution!
  7. Sep 19, 2012 #6
    The best way to reduce CO2 emissions from a car is to walk...

    Seriously though, it sounds ike you got the idea from a pressure vessel filter and thought it'd be funny on a car. Your idea wouldn't work, but it'd be a good project to explain why and calculate the conditions that it creates and why combusiton won't occur inside the engine.
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