Dears,
I would like to check the size of an installed RO downstream blowdown valve in a gas processing plant as it didn't meet the blowdown criteria during last plant ESD (final pressure of 7 bars within 15 mins)
The plant is old & the blowdown time wasn't checked before.
Given:
Operating pressure=88 bars
Operating temperature varies through the section (55 C before contactor , 60 C in the contactor, 30 C after gas gas exchanger)
Composition (varies also)
blowdown valve whose downstrean orifice to be resized installed on gas gas exchanger outlet
Volumes of piping & vessels are known.(40 m3)
Hysys depressurisation utility to be used for peak flow & low temperature check then RO sizing would be completed with another software, but I have the following queries:
1-Which temperature & composition to use
2- Which case to use (fire cases or adiabatic)
3- start from design or operating pressure
4-Concerning valve parameter tab, which vapor flow equation to use
5-Heat flux tab, which heat loss model to use.
& what if heat loss is ignored, How would the calculated area be affected
6-Isentropic efficiency, what is the proper value to use in my case
I know I am asking for a lot of things, but this is my first assignment & I want to return back with reasonable value.