3 replies to this topic

[kasri]

Dears,
I am in need of Critical pressure for a stream in hysys, for that I have to use the critical pressure value obtained from envelope property or Critical property utility.Because for a stream the value obtained from envelope utility & critical property utility is different.Please suggest the correct one to take.
Thanks & regards,
kasri

[joerd]

...Because for a stream the value obtained from envelope utility & critical property utility is different....

That should not be the case. Can you post the hysys case, or the composition of your stream, or as a minimum a screenshot of the Envelope utility and the Critical Property utility results?

[DarrenO]

The envelope utililty calculations in HYSYS and all of its sister programs are done on a water-free basis, so that could be the cause of the difference you are seeing.

[Abdu]

Dear Sir,
I am also have the same doubt as indicated by kasri.
Please suggest from which utility we have to use the value for critical pressure to size the control valve .
thanks,
Abdu