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Vapor density in kg/m3 in CO2 absorber

  1. Apr 7, 2008 #1
    hello all,

    I got a bit of a problem. I want to calculate the vapor density (kg/ m3 or lbs/ ft3) with the following facts:

    temp: 40C
    pressure : 20-31 bar
    flow rate: 1000-10000 kmole/ hr
    MW avg: 10-12 g/ mol (it is a mixture of H2, CO, CO2, CH4, H2O)> mostly H2

    I wanted to know which formula/ method I have to use to calculate the vapor density. Hope someone can help me


  2. jcsd
  3. Apr 8, 2008 #2
    maybe it makes it more realistic when I say this:

    It is about a exit gas from a Steam Methane Reformer after water gas shifts.

    The mol% of the exact compositions are:
    75.22% H2
    19.27% CO2
    4.22% CH4
    0.30% CO
    0.98% N2
    rest is water

    temp is 40C
    pressure: 26.5 bar
    4640 kmole/ hr

    Still hope someone could help with this problem
  4. Apr 10, 2008 #3


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    Gold Member

    Hi Tim,
    You should be able to calculate total density from the partial pressures. Total pressure is equal to the sum of the partial pressures of each constituent. Assume also the temperature of all the gasses in the mix are equal.

    See if this helps at all: http://www.mikeblaber.org/oldwine/chm1045/notes/Gases/Mixtures/Gases06.htm
  5. Apr 11, 2008 #4

    I will look it up in more detail. For now I used the Ideal gas law (assumed it is an ideal gas with compressibility of 1)

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