Water mole % 1

[Pons19]

Hi All,

Please help in getting the mole % from the following,

How to calculate mole% of water from the given Dry basis crude composition.
How to calculate mole% of water from the given Dry basis natural gas composition.

Thanks in Advance.

Kind Regards
Pons

 

[Latexman]

You can't. "Dry basis" means with no water. You need a wet analysis.

Good luck,
Latexman

 

[ATMChemE]

Water will not show up when an analysis is done on a gas, for example. However, we know that gas comes saturated with water. What you want to calculate is how much water it can "hold" and still maintain a single phase. There are several charts that give the various equilibrium curves of water and hydrocarbons.
If you have a simulator handy..A quick and dirty way is mix water with the dry gas (make sure the mix is at the temp n press needed) and then feed it into a 2 phase separator. Or if you have ProMax, you can use their saturator block that automatically calculates the water content of the saturated gas.

Hope this helps.

 

[dcasto]

here is a quick simple water saturation equation

lbs H2O/ MMSCF =(10^(3.5551-0.94283*LOG(psig+15)+0.01576*(temp degrees F-31)))

 

[Latexman]

Gas may or may not be saturated with water. It depends.

Is it always 100% relative humidity outside? No.

Yes, it is convenient to ASSuME this to progresss your calculations, because it is usually the worst case, i.e. conservative. Depending on what happens to the gas downstream, you may want to make this assumption, or you may want to find an analytical method that measures the water. It depends.

Good luck,
Latexman

 

[dcasto]

In 30 years I've never seen a gaswell that produced under saturated gas.