Flowsheet in flowsheet issue

[HenkF]

Hi Jasper,
hope I don't bother you too much...
Attached you will find a flowsheet, with a COFE_Flowsheet UOP uit defined (Superheaters). This Superheater flowsheet runs OK, but passing stream data back to the container flowsheet shows some odd results.
I did make sure that the stream material stream types (composition, name) point to the are set to the same name and composion, and the streams are connected. The calculated steam side exit temperature shows ~507 C from the contained flowsheet (OVO - Superheater), which is in the right range, but the temperature passed to the container is ~228 C.

I guess I'm missing something, an erroneous setup, a units issue? Could you please help me out?

best regards!
Henk

[jasper]

This is an enthalpy issue; the pure streams are being defined by enthalpy when they are transferred to the outer flowsheets. For streams 11 & 14 in the inner flowsheet, you have selected property package "Water", with reference state (flowsheet options page) recalculated at 1 atm, 25c, in the (real) vapor phase.

In the outer flowsheet, streams 142 and 40 (the corresponding ones) use the same thermo, but with reference state being that of the property package itself. The problem will be corrected if you use consistent reference states (either tick them both off or both on). A safer option is always to use the thermo of the outer flowsheet in the embedded flowsheet, in this case it cannot go wrong. Remove the thermo from the inner flowsheet, and add thermo to the inner flowsheet that correspond to feed or product streams to obtain that.

I see however that there is a bug in turning the reference state off: this is fixed now and will be available in the next CUP update (when I am done looking into your other posts).

[HenkF]

I guessed it might have to do with something like this, forgot to check...
Thanks!

[HenkF]

And... it runs! Great!

[jasper]

Excellent. The fix for the reference state toggle will follow shortly.