Flowsheet fails to solve with COFE 2.6.0.31 update

[HenkF]

Hi all,
recently a change has been made to fix the solution loading for energy feed stream. (COFE (2.6.0.31): fixed problem with loading solution on energy feed streams)
unfortunately this may have introduced an error in solving the attached flowsheet. It perfectly solves with the 2.6.0.30 version, but fails with the recent 2.6.0.31.
Could you please have a look? Thanks!

regards,
Henk

[jasper]

It solves. On my side, with the 2.6.

Can you elaborate on what the error is?

[HenkF]

Hi Jasper,
Right! Than I have to check the implementation at my side...
Thanks for your reaction.

regards,
Henk

[HenkF]

Hi Jasper,
Right! Than I have to check the implementation at my side...
Thanks for your reaction.

regards,
Henk

[HenkF]

Hi Jasper,
Right! Than I have to check the implementation at my side...
Thanks for your reaction.

regards,
Henk

[jasper]

ok - let me know if the problem persists.

[HenkF]

I've posted quite some replies. Bit too impatient I guess...

Anyway: another question regarding a unit-op in this flowsheet :
You may recall I was looking for a way to adiabatically operate a flash to simulate a drum. Indeed this has been made possible!

Regarding this : I seem to have gained some 20 MW somewhere in the flowsheet: input/output stream differences at the steam side are some 20 MW higher than those at the fluegas side.
I tried to figure out what the root of the difference could be, and I'm not confident about the drum (flash) result. (see COCOFlash.jpg)

COCOFlash.jpg (127.37 KiB) Viewed 26676 times

The flash has been set to operate adiabatically, but it seems to have gained ~20 MW? What am I missing? Used version 2.6.0.30

COCOFlash2.jpg (99.18 KiB) Viewed 26675 times

COCOFlash1.jpg (21.66 KiB) Viewed 26675 times

regards,
Henk

[jasper]

That does not look right.

Can you send me an fsd with the flash, feed and product streams, so that I can check it out? Everything else can be deleted.

Thanks.

[HenkF]

hi Jasper,
the stripped result.

regards, Henk

[jasper]

The flash is set to TP flash the products. For one of the (pure) products this happens to result the wrong phase. The TP flash should only be used in case the PVF flash (which is the default) returns a result at the wrong temperature. Which cannot happen for a pure compound stream.

So set the "use TP flash" parameter to false, and the problem is fixed as the products will obtain the proper state of aggregation.