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[yog123]

I have to size the PSV on discharge of centrifugal-compressor for blocked outlet case.

 

I have vendor curves (discharge pressure vs Flow, shaft power va flow) available with me.

 

can anyone tell me how to calculate the relief rate for the PSV? I read the other articles on this. i got following steps:

 

 Relief rate should be calculated at maximum suction pressure, but also RELIEVING pressure of PSV on compressor discharge. To exactly calculate relief rate for such a case, follow steps below:

- Get compressor head versus capacity curve for maximum speed
- Calculate maximum compressor suction pressure
- Calculate maximum compressor discharge pressure going backward from PSV (at relieving pressure) to compressor discharge flange
- Calculate compressor differential head from suction and discharge pressures
- from compressor head - capacity curve, read capacity corresponding to above calculated which is relief rate for your PSV.

 

However, i could not understand, how to proceed with the calculation?

 

if anyone has any reference calculation available with them then kindly share.

 

thanks in advance