1 reply to this topic

[arvind]

Hi dears,

I have stuck to define the flow rate to be relieve from concern PSV for the blocked outlet condition for desuperheater. ( please find the attachement for more clarification)

Data:

Superheated steam: Pressure 3.5 barg
Temp. 150°C
mass rate 9000 kg/hr

Boiler feed water pressure 45 barg
Temp. 145°C.

I have calculated the boiler feed water requirement 28.54 kg/hr.
kindly suggest me to decide the maximum relieving rate through this PSV. and its phase?


Thanks in advance

Attached Files

•  PSV_007.doc   96KB   53 downloads

[JoeWong]

You have not mentioned the superheated steam design pressure, i presumed it is same as desuperheated design pressure. So superheated steam will not result overpressure of desuperheated section.

Then the possible overpressure will come from Boiler Feed water (BFW) side in the event of blocked outlet (and BFW control valve failed to full open position). You may ask control valve vendor to estimate the maximum flow through control valve when :
i) maximum pressure occur upstream of BFW control valve
ii) PSV is 110% of set pressure
iii) control valve is full open
The flow will probably the PSV relief flow...