Staggered Blowdown Valves

[tika5828]

I am a fresh grad of chem-eng. And I have an assignment to simulate staggered BDVs. This is because the capacity of flare is limited, so I have to staggered the openings of BDVs. I have to simulate this using HYSYS (combination of depressurizing utility & event scheduler. Have you ever simulated this before? Please advise. Thanks

 

[MortenA]

Are you using steady state or the real dynamic HYSYS?

Morten

 

[tika5828]

Morten,

I have to use HYSYS dynamics to get the Pressure vs Time graphic (stripchart). Lets say that I have 3 BDVs that shall be opened in every 5 minutes, so that in the 15 minutes the pressure remains 100psig. Do you have some materials that covers this staggered BDVs simulation?Or something that related?

Thanks,
Tika

 

[MortenA]

Just making sure that you knew the difference between the "true" HYSYS dynamics and the use of the depress routine in "normal" SS HYSYS.

Anyway: Material as such - no.

Just remember that the 900 secs from API is from start of blowdown and until all units must have a pressure lower han 7.XX barg (or what ever ) . So - if one BDV has a delay of say 60 secs - then blowdown must be completed in 840 secs.

Apart from that I would say its a bit like eating an elephat: You have to do it bite by bite.

Best regards

Morten

 

[tika5828]

Morten,

Would you please explain the difference between "true" hysys dynamics & "normal" ss hysys? I am still a newbie, and I have just learned a little bit about dynamics...

U're right, it's like eating an elephant..I am starting to do it step by step:
1. I have simulated depressuring only to get Cv of those 3 BDVs using depressuring utility
2. I learned about event scheduler works
3. I am still trying to make isolated system using block discharged scenario (since I think fire case scenario is more difficult)

Give me some advice so that I can make sure that what I do is right

Many Thanks,

Tika