2 replies to this topic

Hi everybody

Do you have an idea or website that can help me to convert mol fraction of water in gas to lb water/MMscf and then to mg/m3.

Thanks in advance

[djack77494]

Hi everybody

Do you have an idea or website that can help me to convert mol fraction of water in gas to lb water/MMscf and then to mg/m3.

Thanks in advance

No website, but do it in a very direct fashion.

Start with 100 moles of wet gas. Moles of water = mol fraction * 100
So now you have moles of water
Multiply by 18, and you get lbs. of water.
Moles of gas = 100 - moles of water.
At what I call STP = 60F & 14.696 psia, 1 mole = 359 scf
(Always take the small extra effort to specifically define what YOU mean by STP.)
Moles of gas * 359 = scf of gas
Divide by 1,000,000 to get MMscf of gas
Now you have lbs. of water & MMscf of gas.
Divide former by latter to get your answer.
I'll let you try part 2 on your own now that you got the approach.
Doug

Dear djack77494

Thanks a lot for the explanation and I appreciate your help.

I have found a straight way to do it.

y (mole fraction of water vapor)

multiply y by 792000 to obtain kg/Mstd m3
multiply y by 47484 to obtain lb/MMscf (@ 14.7psia & 60F).

I prefer understanding the conversion as you stated rather than remembering the number.

Petrol