non condensables in HE

[eaw11]

I am attempting to size a condenser (from a process standpoint, not mechanical) and am looking for any information on how to do this with non condensables in the system. I have cooling water in the shell entering at 10 degrees C from a chiller. Through the inner tube I have a mixture of steam, NOx vapors, and air entering at 100 degrees C. This will be a countercurrent flow HE. I am trying to do a process design for the small scale heat exchanger and the mechanical design/fabrication will be done by an expert

I understand all the heat balance equations and such, but I am unsure how to calculate heat transfer coefficients with the non condensables in the system.

Any help/suggestions is appreciated.
Thank you

 

[Jalink]

eaw11,

Do not know whether you want just theoretical or more practical suggestions. Herewith only two (2) theoretical suggestions:

(1) As the medium consists of non-condensables and condensables, you can assume near the pipe wall an area (distance) where condensables will deplete. In this area poor of condensables a diffusion process is present, where condensables will have to diffuse from the bulk (centre of the pipe) towards the pipe wall.

(2) Pending on the amount of non-condensables removed from the heat exchanger pipe(s), the bulk will get more pore off condensables and the system will shift more from convective transport to the condensor pipe to diffusive transport.

 

[rmw]

Why do you have your cooling water on the shell side and your condensing vapor inside the tubes?

Is this a necessity of the process or your choice. If I can convince you to put the condensible/non condensible mixture on the shell side, then I'll make comments.

rmw