mixture of 2 fluids in tube side of shell and tube condenser

[KDBT]

Hello every one
I am new to shell and tube heat exchanger design. I have water at shell side and methanol and methyl ester vapor at tube side , my question is
1. can we provide 2 different thermo-physical type of fluid at tube side in a single heat exchanger
2. If yes can some one provide me basic design calculation eg. of such type of case .I already done process design for shell and tube heat exchanger for water and one fluid at tube side.

 

[Latexman]

A drawing/sketch is worth a thousand words.

Are the methanol and methyl ester vapors kept separate or are they a mixture?

Good luck,
Latexman

To a ChE, the glass is always full - 1/2 air and 1/2 water.

 

[EdStainless]

Are you trying to condense the meth...?
Are these large diameter tubes (>1.5")?
Are the tubes vertical?
Condensing inside of small diameter tubes is very inefficient and can present some interesting flow issues.

Using mixtures is common enough that most chem process texts have examples.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[georgeverghese]

Use the lower of the 2 condensing coeffs you'd get, assuming the physical props for pure methanol or pure methy ester vapor on the tubeside. Calculations for mixture physical props could result in large errors.

 

[KDBT]

hello Edstainless
yes i have mixture of both fluid which will condense .
tubes are of 1 " only
can be vertical or horiz. I am using HTRI for thermal design and it does not provide 2 input for tube side in STHE.it keep asking me prove vapour weight fraction and at this point i do not have that .

 

[davefitz]

As I recall, there are publically available computer programs developed by NASA , sold through COSMIC ( at the Univ of Georgia), that deal with the thermnodynamic properties of mixtures. Other recent 2 fluid processes include the ammonia water mixtures ( eg, kalina) , and binary hydrocarbon mixtures used in the LNG liquifaction business.

"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick

 

[georgeverghese]

Would suspect that methanol and this unidentified methyl ester are probably a non ideal mix, so you'd get low accuracy with many of the run of the mill predictions for mixture physical properties.

 

[Latexman]

Methanol and methyl acetate form a minimum boiling azeotrope.

Process Heat Transfer by Kern has a chapter titled, "Condensation of Mixed Vapors". Most books on process heat transfer will.

Good luck,
Latexman

To a ChE, the glass is always full - 1/2 air and 1/2 water.