4 replies to this topic

[seeker_of_knowledge]

Hi All,

 

Trying to solve the following problem from Himmelblau's chemical engineering book Chap 17 Sec 17.2 (Condensation):

 

Two hundred lb of water out of 1000 lb is electrolytically decomposed into hydrogen and oxygen at 25 C and 740 mmHg absolute. The hydrogen and oxygen are separated at 740 mmHg and stored in two different cylinders each at 25 C and 5 atm absolute. How much water condenses from the gas in each cylinder?

 

Answer given in the book is: 2.69 lb in the oxygen cylinder and 5.67 lb in the hydrogen cylinder.

 

I am trying to apply concepts of condensation of saturated gas as per the book but so far no success. 

 

Can anyone help with this please?

 

Thank you,

 

Fez

 

 

[Art Montemayor]

Please submit your detailed, step-by-step, calculations on an Excel spreadsheet so that our Forum members can see the logic and justification of your work done to solve this problem.

 

If you want and need expert help, then you must at least help those who would help you to understand what you are doing or thinking wrong.  Doing your work for you is no way to help you become an engineer.

[seeker_of_knowledge]

Dear Art,

Thanks for reply. By no means I wanted someone to do my work. I was expecting general idea on the steps to take. Today only I was able to solve this problem after thinking about this over and over again for the past couple of days. This is how I solved it:

Started off with an equation of water decomposition and determined amount of H2 and O2 gas produced. Calculated amount of water in the vapor liquid mixture using vapor pressure at given temperature and system pressure. Then determined total amount of condensed water by calculating mole fraction of water in vapor phase in each cylinder. Using ratio of vapor-liquid mixture distributed in each cylinder and total water condensed, I was able to calculate how much water is condensed in each cylinder.

Please let me know if this makes sense. I can defintely upload excel spreadsheet with the solution.
Regards

[Art Montemayor]

You don't seem to read all of my comment: if you have done the calculations and want confirmation on their correctness, then SUBMIT YOUR DETAILED, STEP-BY-STEP CALCULATIONS.  That is how engineers work.

[seeker_of_knowledge]

Please see attached file for steps I took to solve this problem and confirm if you agree. 

 

Thanks again,

 

Attached Files

•  Condensed water from compressed water.pdf   339.84KB   12 downloads