Emergency Depressurization (EDP) System design
Our Hydrocraker unit has two emergency depressurization systems : 7 bar/min (100 psi/min) and 21 bar/min (300psi/min).
Unit design pressure is 160 barg and feedrate is 86 m3/h
Licensor assumes that EDP system (RO + Valve) is designed to decraease pressure unit by 7 bar or alternatively 21 bar in first minute .
Today unit is operated at higher flowrate (128 m3/h) and lower pressure (145 barg)
A depressuring test done in the new conditions showed that the depressuring rate decreased at 18 bar/min instead of 21 b/min in first minute.
Is this new depressusing rate still acceptable or should EDP valves and Restriction Orifice be resized to target 21 bar/min?
Refinery situated in the Ivory Coast