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[maitreyee ghosh]

I'm trying to simulate main heat exchanger box of an air separation unit in Aspen plus. There are four cold streams to be heated up by the incoming air which is available in different temperatures and flowrates from the following sources.
1. from main air compressor at around 6 barg pressure and 31 0C
2. from expander outlet at 6 barg pressure and -168 0C
3. from dense fluid turbine outlet at 6 barg pressure and -178 0C

my question is, is it correct approach to put all the cold streams and the hot streams together in a plate type exchanger or should I take one exchanger each for each pair of streams. I didn't take the later approach as there are 3 hot streams and 4 cold streams and I'm also able to get desired output but not sure about the accuracy and the practicality of the simulation.
Please help.

Maitreyee

[jcazenave]

Did you try to use the MHEATX block? I think that this should be the right block for this exchanger.

If not, what you are describing is call a composite stream and it is used as a first approximation to calculate multi-streams heat exchanger.