Blowdown calculations using HYSYS 3

[enguest]

Dear all,

Could you please help me with the following query:

Now I am doing the blowdown calculations for the gas injection manifold. It is 16" Manifold with 10 meters line with enlarger at the end (increasing line size to 6") and blowdown orifice on the 6" line. Is it possible to use the depressuring utility in HYSYS to calculate the blowdown time and final temperature, taking into account that flow upstream of orifice can be already choked?

Thanks in advance.

 

[PaoloPemi]

I am not familiar with your simulator and I can't confirm, however for the sake of discussion I would add that in most cases you can solve these problems with Excel and a library (see

http://www.prode.com/en/properties.htm

for example), the depressuring (blowdown) calculations are not difficult, there are several examples available and you can customize parameters (in your case the piping) as requested.

 

[MortenA]

If you have the full dynamic license for HYSYS then i think the answer is: Yes, if not then: No

Best regards

Morten

 

[tickle]

not used Hysys for a while to calculate depressurisation, but I have used the vessel depressurisation utility - in steady state mode. I think that there is a tutorial on it.

 

[MortenA]

Thats not the question tickle - the question is: Can you add model choking in the upstream piping for the depress module?

My answer is: No, not for SS HYSYS anyway.

For dynamic hysys i would be inclined to say yes (but im not sure)

Best regards

Morten

 

[tickle]

Yep sorry I missed the question. I assumed an orifice going to atmosphere. Morten is correct that you cannot model both choking at one point and blowdown at another in steady state.

The size of the line upstream of the orifice is not given, but it is reasonable to assume that it will be larger than the orifice bore, and choke flow will occur only at the orifice. If choked flow is occuring at the end of the line to the orifice then this would be the controlling point and can be put into the depressurisation utility.

As I said, I have not used the depressurisation utility for a while and cannot remember the details, but I would still recommend having a look at the Hysys tutorial.

 

[enguest]

Thank you very much for all your comments they seem very useful.

 

[SNORGY]

I have not used it myself (Mechanical) but my colleagues (Process) advise me that dynamic HYSYS indeed does model this.

Regards,

SNORGY.