Dear experts:
There is a storage tank with N2 blanketing system which consists of a PCV and a vacuum breaker PSV.
During the unloading, tank pressure reaches to vacuum breaker set pressure and that is why instead of N2, air goes to the tank.
My question is that. What is the role of PCV during unloading?
Is it ok to allow air interring the tank?
Regards
Rohollah