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Separating Gases from a mixture

  1. Sep 4, 2014 #1
    Well i need to separate NO2 from cars exhaust to then produce nitric acid and the use it in other reaction. The problem is that i have other byproducts such as SO3 and many more, so i cant make nitric acid without producing other acids. What i was thinking is. Since NO2 have a very high boling point ( 21°C/69.8 °F) i wass plaing to cool that mixture to a lower temp than that. would NO2 fall into liquid state completely separating it from the other mixture ? and if dont any other idea? Its for my scienc proyect.(sorry for my english)
  2. jcsd
  3. Sep 4, 2014 #2


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    SO3 is even solid at room temperature, so I fear this won't work. What other reaction do you have in mind for the second step?
  4. Sep 4, 2014 #3


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    I don't if it is practical, but a centrifuge may work using the gas.
  5. Sep 5, 2014 #4

    sorry. I was ment to say, SO2 which have a vaporization point at -10ºC.the reactions that i want to make are: convert the NO2 that i extract into nitric acid by adding water and then reacting it with amonia to produce amonium nitrate. The idea of the proyect is to reduce the amount of acid thrown by cars into the enviroment, and using it into something ( amonim nitrate is a fertilizer.)
  6. Sep 5, 2014 #5


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    It is perhaps impractical to apply a process at the source, which is where it would be most effective. The process requires a container (and processing equipment), which adds mass to the car, a piece of equipment that needs replenishment and/or repair, and cost.

    One can look at fossil-fired plants to see what 'scrubbers' are used. For NO2, catalytic converters are used, but SO3 can 'poison' them, which is why low sulfur gasolines have been developed.

    One may wish to research 'scrubbers' or gas scrubbing technology to remove SO2/SO3 from the exhaust.
  7. Sep 5, 2014 #6
    Maybe adsorption/elution??? You could have two tubular beds in parallel, and could be eluting one bed while adsorbing on the other. Just a thought. Sounds like it might be a little too complicated for attaching to a car. Alternately, you could just have adsorption, and periodically switch the bed, like one does with a water softener.

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