Valves In Hysys V8.0

[FuriousGeorge]

I'm currently working with simulations on Hysys V8.0 and i keep getting this error: "flow rate, pressure drop and opening should be non zero. Unable to size valve..."
This valve connects the steam output for a CSTR reactor, problem is due the simulation is in dynamic state i can't modify the values for the steam line because hysys won't let me.

Is there any steps i'm missing to be able to modify any value?

Thanks in advance.

 

[chengg29]

FuriousGeorge,

It would be better if you could mention more details on the nature of the problem. However, prima facie, I can say from what I have encountered earlier is that although the intial default opening of any HYSYS valve unit operation is 50%, once you take an intial dynamic run (after switching over to dynamic mode from the converged steady state mode) some of the valves do change their openeings at different intervals of time depending upon the disturbances / perturbations that you may have built into the simulation (in the Event Scheduler for instance). Hence this % opening for this valve would have become zero during one particular time instance. However I am sure you may have noticed this anyways in case this was a problem

Cheers