26 replies to this topic

[paulhorth]

Chiks,
Thank you.
Yes - either that section of piping and the two valves need replacing with 300# items for the higher design pressure of 39 kg/cm2g,
or you can reduce the set point of the PSV to 16.7 kg/cm2g, and check that its capacity is OK for blocked outlet at that pressure (in the way that we have discussed earlier).
Likewise with the first stage discharge, but there it should be simple to reset the PSV from 8.0 to 7.7.kg/cm2g.

Paul

[CSNK]

From this i can conclude:-

1. 1st stage PSV - set pr to be change to 7.7 Kg/Cm2 or either line to be re-rated - relief load to be calculated using max flow ( at max suction pressure)
2. 2nd stage PSV - pipeline to be re-rated - Relief load to be calculated using max flow (at max suction pressure)
3. For interstage drum PSV - Relief load calculated in 1.- to be used considering antisurge valve failure.

Thanks.