Determination of Tank Vapors Using ProMax

[Berenger]

I need help from anyone who's familiar with ProMax. I have a tank that gives off 2.169 mscfd of vapors (according to ProMax). Naturally, I thought this will be the volume we need to size for the flare (small flare solely for this tank vapor). However, I was told that that is not the volume because I have to adjust for water vapor in the gas. Does anyone know how to correct the vapor volume for water vapor? I was told that the corrected volume should be close to 5.4 mscfd?

I have attached the sample composition. I don't need anyone to solve this for me. However, can you please point me in the right direction?

Thanks.

The stream properties are:
Std flowrate = 2.169 mscfd
T = 120.9F
P = 0.25 psig
Vapor fraction = 100%
Mol Wt = 23.2168
Mass flow = 5.53 lb/hr
H2S total mass flow = 0.00028144 lb/h
H2S total mole fraction = 34.67 ppm
Methane total mass fraction = 42.61%
Ethane total mass fraction = 8.821%
Water total mass fraction = 9.0523%