1 reply to this topic

[LeoLeo]

Hi all,

 

I want to ask your opinion regarding modifying set pressure based on liquid overfilled scenarios .

Based on ASME, design pressure for pressurized vessels is identified for top of the equipment. In many cases, we consider set pressure equal to design pressure.

 

Now, imagine a vertical vessel (height of 10 m and design pressure of 10 barg) and PSV is located at top of the vessel. For liquid filled scenario (with water), we consider relief pressure of 11 barg (design pressure plus 10% over pressure). This means the pressure at bottom of equipment will be 12 barg (relief pressure plus liquid static head).

 

The set pressure has to be adjusted based on location of PSV and liquid static head. I believe we need to consider liquid static head from outlet nozzle of equipment (on top) to PSV inlet as general rule and not consider liquid static head from bottom of vessel.

 

In some cases in industry we have different design pressure for top and bottom. In these cases, we need to assure we do not exceed design pressure of bottom for overfilled scenario.

 

Do you agree?

 

ARM

[Bobby Strain]

One must sort these details during vessel design stage.

 

Bobby