3 replies to this topic

[ayan_dg]

Hi,

MAWP of the vessel is 100 barg.

One PSV is set at 100 barg and the other at 105 barg.

Case is blocked discharge the whole relief flow goes out through this two PSVs.

Accumulation is 16% (multiple PSV).

Both the PSVs are required for blocked discharge case.

 

The two PSVs lie on a common header.

 

For this particular situation the 3% frictional pressure drop criteria for inlet line should be calculated based on

 

i) Rated capacity of each PSV for individual inlet lines and required capacity for the common header ,

 

Or

 

ii) Rated capacity of each PSV inlet line and sum of rated capacities for the common header.

[fallah]

ayan,

 

Please specify the relieving fluid status and PSV type...

[ayan_dg]

Fallah,

 

Balance bellow PSV, discharge to flare , vapor discharge only.

[fallah]

ayan,

 

In general, considering the cross sectional area of common header not to be less than summation of those of individual inlet lines, it should be calculated based on case ii, i.e. rated capacity of each PSV for individual lines and summation of rated capacities for common header...