differences in dynamic simulation in HYSYS V7 compared to V3 and V8 !

[Dimmethylamine]

Hello Every Body,

please I would like to ask about the differences in HYSYS V7 compared to older or newer versions, how can I make it give the same results especilally in the estimation of vessels volume, the valves cv ... ?

Thank you very much

 

[Latexman]

Try giving it the same inputs, using the same components, using the same compositions, using the same physical property and thermo models, using the same unit operation blocks, etc. I.e., duplicate everything, as much as possible.

Good luck,
Latexman

Technically, the glass is always full - 1/2 air and 1/2 water.

 

[Dimmethylamine]

thnx a lot latexman, this is basically what I did, Every thing was the same, but the results diverged "painfully" !

 

[Latexman]

Are both cases converged? And, is the convergence criteria the same? I recommend HYSYS tech support if you are sure there are no differences.

Good luck,
Latexman

Technically, the glass is always full - 1/2 air and 1/2 water.

 

[georgeverghese]

What about process controller P , I , D settings? Are they the same for both cases?
Are setpoints for controllers and trip transmitters the same ?

 

[Dimmethylamine]

the first step when doing a dynamic simulation is to estimate the cv of the valves and the vesels volumes isn't it ? and that's done either manually or automatically via dynamic assistant, And that's where lays the problem guys, I guess Aspen has introduced a different strategy in V7. I've been told it can be adjusted so that it gives the same results as older versions, but I cdn't figure out how !

deepest thanks though, gentelmen.

 

[MortenA]

Why dont you aske Aspen, they probably get these questions all the time and have some worked through examples?

BTW, you state "how can I make it give the same results especilally in the estimation of vessels volume, the valves cv ... " but in DYNAMIC these are inpus not results?

 

[Dimmethylamine]

thanx mortenA, this is my first contact with this software, I will try asking on Aspen forums.
As for the parameters, they can be estimated through the dynamic assistant. I tried introducin them manually, it helped a little bit, but there might be other parameters that need to be adjusted.

 

[MortenA]

Ah, but the estimations are "reverse engineering". So your input must (of course) be identical. But you could also just puch in the numbers that the older version gave you and disregard that the new version give a different result. This is just a fact of life- or you should not upgrade ([/irony on] what would be the point? The previous version gave perfect results that was undeniable the thruth [/irony off]). If you are simulating an existing plant then of course you must use actual numbers not estimated.