Fractionation column blocked discharge psv sizing case

[ChemEngSquirrel]

I have a demethanizer column and im sizing the psv for the blocked vapor outlet case.

Ive simulated the scenario in hysys with max reboiler duty allowed for in the model.

Is steady state simulation the correct approach for this scenario?

Thanks.

 

[CMA010]

Difficult to say without more details

 

[georgeverghese]

Does the PSV on the expander exit (which would be upstream of this DeC1 column) also have the same set press as this column PSV?

 

[ChemEngSquirrel]

No psv on expander exit. Column psv protects the hp/lp interface.

 

[georgeverghese]

Additional boilup of C1 from reboiler would be small in relation to the vapor leaving the DeC1, hence the steady state simulation with design case flow (with all flow margins included) would be ok.

However, the other controlling case for this PSV would be the exit flow from the expander when running at max normal speed, with max normal feed pressure and min normal feed temp to the expander.