Derivation os Mass Flows for Air Components From Air Flow-rates

Multiply by density and multiply by mole fraction of each constituent gas.

Thanks PWSlack,

But my question is what values for density and molar fraction must I take? I mean, what are the values for humidity and what for the molar fraction of each consituent at Normal conditions? Does the density of air at normal conditions depends on the humidity value? If so, what is the humidity of air at Normal conditions?

Measure them.

Why do you not look in a source as Google about air composition ? Make an effort and try first to find data by yourself and then if you do not come further ask for help.

CR4 is NOT here to make your job but ONLY to help you if you are in need!

Nickname, thanks for your polite reply and great help. Anyway, obviusly the aim of my question was to get feedback from experts in the matter not from people who have no idea.

BTW, I posed my question after visiting a lot of websites with no satisfactory answers.

Then what is your problem exactly and I shall be glad to answer it in a satisfactory way. The fact that I did not answer does not mean that I do not have any idea about only that I am not willing to make the work the OP should have done before.

1. First of all, you need to know the composition of air. You can use the well established composition (volume or mole)and adjusted for humidity.

2. Divide flowrate in NM3/h by 22.4 to get k-mol/h.

3. From the composition, you then can calculate each component composition to get the individual flowrate in k-mol/h. (for ideal gas, vol% = mol%)

4. Multiply by molecular weight for each component to get the mass flow rate in kg/h for each component.

Hope the above gives you the idea

The percentage composition of dry air is the same at whatever temperature and pressure (above the boiling points of the respective gases), but to answer the question you must have a value for the humidity. This would normally be as a percentage of the saturated content at a particular temperature, so when you have that percentage value, you need to find the saturation partial pressure at that temperature, and from that calculate the actual water vapour pressure. Subtract that from the atmospheric pressure and you have the sum of the other partial pressures. You can then express each partial pressure as a percentage of the total atmospheric pressure, and the flows are then in proportion to those percentages.

Understood!!! That is what I needed to know.

I appreciate your help.