5 replies to this topic

[Europio]

Hello,

 

I have a gas with dry basis composition. I also know that is saturated in water and the inlet and outlet pressure and temperature of the gas. I need to calculate the amount of water that condensates during cooling as you can see in the Excel attached, but something is wrong because the mass balance don't match...

 

What is wrong? How can I do it correctly?

 

Thank you very much.

 

PD: Inflow pressure and temperature, outflow pressure and temperature and specific gas constants are my original data (green filled cells).

Attached Files

•  CondensationRev1.xlsx   22.44KB   37 downloads
•  Condensation.xlsx   19.17KB   22 downloads

Edited by guillermocp89, 19 December 2018 - 07:05 PM.

[Art Montemayor]

Willie Noneofyourbusiness:

 

You state you have a gas saturated with water and “need to calculate the water condensation during cooling” - but you fail to state WHAT it is that you are calculating (or trying to).  Is it the amount of water condensed as a liquid by the cooling?  Or is it the thermo properties of the gas or the condensate?  Your explanation isn’t clear.

 

You failed to attach the Excel workbook you mention has the calculations.  To attach the workbook, do the following:

1. In the section of "More Reply Options", click on “Choose File” under "Attach Files";
2. Select the file you want to attach from your computer’s hard drive or other connected drive and click "Open";
3. Click "Attach File";
4. Finally, click "Add to Post" and the selected file will be attached to your post.

Our members may be able to find what is wrong with your calculations if we can see your spreadsheet calculations and they are detailed and step-wise.

 

Yes, you can make the condensation calculation in a simulator - like HySys.  But you must be able to operate the simulator correctly.

[Europio]

Sorry, I am trying to calculate the amount of water that condensates. The Excel is now attached.

 

I have just do it in few minutes with HYSYS (much easier as I thought), but I need to do it in Excel or by hand.

[Art Montemayor]

Willie Noneofyourbusiness:

 

Your spreadsheet is very well presented and organized.  (This is the kind of calculations I'm used to seeing from Spanish engineering students)  The condensed water content values calculated can now be checked.

 

However, you didn't list your NOMENCLATURA.  Without a listing of the nomenclature, it is difficult and tedious for our members to follow the algorithm(s) you used to make the calculation.  Can you please furnish a nomenclature listing and explain the steps used in your algorithm?  The checking would go a lot faster ........

Name the revised workbook as CondensationRev1.  That's the way we engineers work.

 

Saludos

[Europio]

CondensationRev1 attached. I hope now it is clear enough. Thank you.

[PaoloPemi]

I would start calculating the mole fraction (and amount) of water at initial conditions (in vapor pahse) from -> Ptot = P1*x1 + P2^x2 +...
then, at specified condition, calculate (mass balance) the max amount in vapor phase and the condensate fraction...

by the way, you can do that with a simulator as Hysis or a thermodynamic librariy as Prode, these calculate the fugacities of the different components in the mixture with a equation of state or similar models, it could be interesting to compare these values with those calculated with the ideal model...