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We have crude distillation unit and normally operated at 0.3 kg/cm2 top pressure.
Since the change of feed composition which tend to the lighter crude then the operating pressure reach
0.9 kg/cm2.
do you have any experience to limit the operating pressure of CDU in order to make sure valve tray inside the column not released from the tray itself?

More info:
Maximum allowable Working pressure of CDU Column is 3.5 kg/cm2
Desain operating pressure is 0.6 kg/cm2 (top pressure).
 
Answers
11/10/2016 A: GAURAV BURDE, Bharat Petroleum corporation limited , burdegaurav88@gmail.com
There is no problem to valve trays in operating column at higher pressure.
However, you can optimize pressure by increasing pump around or circulating reflux of the Column.
20/06/2016 A: Rajkumar Chate, Sulzer, rajkumar.chate@sulzer.com
Valve tray has nothing to do with the operating pressure of the column. Rather than operating pressure, pressure drop across each tray is important for any mechanical damage in tray (valve flown off or tray panel disalignment / fall).
17/06/2016 A: Ralph Ragsdale, Ragsdale Refining Courses, ralph.ragsdale@att.net
Operate at as low a pressure as possible to minimize utilities usage. The trays will be O.K. at higher pressures.
15/06/2016 A: Eric Vetters, ProCorr Consulting Services, ewvetters@yahoo.com
The absolute pressure is not a factor in causing valve trays to lift out of place. Instead it is the delta P across the tray that makes a difference. Unless specified otherwise, the standard design is typically for 1 psi of uplift resistance. More robust designs will use 2 or 3 psi uplift. The DP that blows trays out normally comes when liquid water accidentally enters a hot part of the tower or if you get a high level in the bottom of the tower that causes massive upward entrainment of liquid.