non condensables

[eaw11]

I am attempting to size a condenser 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. 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 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

 

[dcasto]

The noncondensibles will only have sensible heat removed. The steam will have a combination of both heat of condensing and sensible.

 

[wfn217]

The non condensibles will reduce the condensing side heat transfer coefficient.

 

[srfish]

First you will need to develope a condensing curve since this mixture will not condense the steam in a linear manner.
The calculated heat transfer surface will need to be zoned because the heat transfer coefficient will vary considerable throughout the temperature range. I haven't looked at Kern in a long time but I believe he discusses this in his book.

 

[djack77494]

If you are not an experienced heat exchanger engineer then I suggest you do not attempt doing this. To properly size an S&T exchanger, you will need the appropriate software, such as HTRI's software. If you don't have a product like this, and the appropriate level of experience, don't even think about doing the mechanical design of an exchanger. Also, what is the source of your cooling media at only 10 degrees C?

 

[eaw11]

A chiller will be pumping the 10 degrees C water to the condenser.

I should specify that 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 need a close approximation of the desired dimensions, but I am unsure what type of correlations to use to account for the non condensables. Thank you.

 

[srfish]

Following up on my earlier post, You can find a recent publication concerning the heat transfer coefficient in the Heat Exchanger Design Handbook in section 2.6.