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[M_Menessy]

Dear All,

 

Thanks for your great help. As usual I have a question regarding the procedure of how to use flarenet in flare system design. Correct me if I am wrong:

 

1-      Hysys is used to determine the RO area/diameter required to depressurize the system to its half of design pressure or below 690 kPa within certain time ( 15 minutes in many cases)

2-      I am using valve flow equation of “relief”

3-      After determination of the peak flow through the valve from Hysys, Flarenet is used to check the backpressure on the system (backpressure was assumed in Hysys to be atmospheric to be more conservative)

4-      In cases where the flow is subsonic, changing the assumed backpressure in Hysys should be replaced with the calculated value from Flarenet till both backpressures are the same.

 

Here come my questions;

1-      In Flarenet as all you know, I have to kind of sources either control valve or PSV. Control valve is used to simulate the BDV in cases of emergency depressurization.  How can I define the control valve parameters based on Hysys calculation of RO. I mean Hysys gave peak flow and RO area. I can define the flowrate for the control valve in Flarenet but what about the RO area.

 

What I did is having a control valve followed by small length pipe (600 mm minimum), the RO with the calculated area from Hysys and finally a long pipe to simulate the connecting pipe between the BDV and flare.(please find the attached image)

 

2-      Also, as we are in preliminary phase of the project, is it possible to use layout to have rough estimate for pipe length after multiplying that length with length multiplier of 1.5 for example

 

3- What about the inlet temperature to the RO. Shall I take it from Hysys as "Vessel fluid initial temperature- Vapor phase".

 

Sorry for these basic questions as I have just started to work in relief and flare systems.

 

Thanks in advance

M Menessy

Attached Files

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Edited by M_Menessy, 23 September 2014 - 02:35 AM.