1 reply to this topic

[AmmarJM]

Hello

For one of my projects, I have to develop a monitoring tool for a 2 phase heat exchanger so as to see the effects of fouling over time (i.e if duty is decreasing, we know its time to clean up the exchangers). It is a shell and tube heat exchanger, with propane/propylene mixture on tube side and cooling water on shell side. The process vapours enter as superheated vapour, and exit as subcooled liquid. I have the composition of the inlet and outlet compositions, as well as inlet/exit temp of process and water. I also have inlet pressure for process stream. Can someone tell me how to go about doing this, as I am not sure how to find heat duty (accounting for phase change), and also with variable water/process flowrates/pressures.

thanks

[pdender]

it depends from the level of accuracy which you wish to obtain,

you can define a simplified model (for example based on a series of measured values) or a rigorous model, 

for a rigorous model the thermodynamic solution (i.e. one or two flash operations at specified enthalpy and pressure to obtain outlet temperatures) should not be that difficult, for realtime operations you may write your own code including your own routines for thermodynamic calc.s or a link to a simulator or a process library (as example I suggest PRODE PROPERTIES),

for correlations for heat transfer there are books and free codes available,

in my library I have Kern, MacAdams and the Heat Exchanger Design Handbook, these have all the information which you need.

Edited by pdender, 30 May 2013 - 03:13 AM.