5 replies to this topic

[flarewolf]

Hello

I need to size a PSV for a HE tube rupture case; tube side supercritical CO2 @2038 psig OP, shell side CW @80 psig OP.

I'm using the method outlined in API 520 Annex B to define the tube rupture flowrate, so I need to perform an isentropic flash from tube side P to shell side P, and table all P, T and density values for each P (20 psi steps for each calculation).

How can I perform this operation in hysys?

Thanks

 

[breizh]

Hi,

Consider these resources to support your work.

Breizh

Attached Files

•  Designing_for_Pressure_Safety_Valves_in_Supercritical_Service.pdf   170.76KB   18 downloads
•  Aspentech equations-and-example -benchmark-calculations-for-emergency-scenario-required-relief-loads_compress.pdf   10MB   14 downloads

[flarewolf]

thank you breizh

my issue now is how to extract properties from hysys for the expansion from tube side P to shell side P

[latexman]

thank you breizh

my issue now is how to extract properties from hysys for the expansion from tube side P to shell side P

You cannot use HYSYS to do the isentropic flashes, thus not needing to extract physical properties?  The boundary condition and intermediate condition physical properties should be available once you do the isentropic flashes.

[Said Salim]

You can use NIST Web book to get CO2 properties at different conditions

[astro]

thank you breizh

my issue now is how to extract properties from hysys for the expansion from tube side P to shell side P

Old thread but I've been dealing with this recently.

 

Not sure precisely what flarewolf is after exactly but the approach that the crew I work with uses Hysys or Unisim to generate a property table that the user designs by selecting streams and parameters to generate a bespoke data table. Once the simulation runs, it populates the table.

 

Then it's just a simple copy/paste across to a spreadsheet to populate the various properties required to generate an input data set. One approach is to determine theoretical mass flux, G and other parameters to work through the isentropic nozzle mass flux method. Refer API STD 520 Part I, Annex B. B.1 Development of Flow Equations provides a full run down of the method along with a worked example.

 

The standard has all that you should need. Apologies in advance, I can't share the spreadsheets that I've got that applies the method. They carry corporate IP. No problem for clever people though. API have set it all out for you - just apply standard methodology and good old engineering judgement and you should be fine.

 

The tricky bit is to select your property package and validate the equation of state (EoS) you're using. CO2 can behave somewhat strangely above the critical point, so as long as you've done your research there, you should be good to go.

Edited by astro, Yesterday, 10:35 PM.