Pressure Safety Valve Sizing Calculation Rev.01.xls

STD CALCULATION FOR PSV SIZING

PRESSURE SAFETY VALVE SIZING CALCULATIONS VAPOUR OR GAS RELIEF 12-Jun-13

Client: Job No: Project: Tag No: Location: PROCESS DATA Vapour or Gas Relief Fluid Relieving Scenario Vessel Design Code Mass Flow , W kg/h Gas Molecular Weight, M kg/kmol Relief Temperature of Inlet Gas or Vapor, T °C Compressibility, Z Cp/Cv , k RV Set pressure bar(g) Back Pressure bar(g) Back Pressure Correction Factor Kb (Default value = 1) Coefficient determined from an expression of the ratio of the specific heats (k = CP/Cv) , C Accumulation / Overpressure . CALCULATIONS / RESULTS Absolute Upstream Relieving Pressure. P1

5400 28.00 50.00 1.00 1.40 13.00 10.00 1.00 356.06

%

242.79

psia

128.26 Subcritical Flow Balanced Bellow 0.975

Calculated Orifice Area, A

inch2

0.644

Selected Orifice Selected Orifice Area Relieving Capacity of Selected PSV

inch2 kg/h

H 0.785 6583

Preliminary PSV Size (Inlet x Outlet) Orifice Designation

Self Chk:________ Date:________

582

R

User Input for Kb (Optional).

.

21

psia

Critical backpressure , Pcr Critical flow / Subcritical flow Type of SV Effective coefficient of Discharge, Kd

11905 lb/hr.

Note, do not exceed defaults.

Default Value as per API-520. Refer Table 1 of API Std. 526

2"x 3" H

Chkd:________ Date:_______

Apprvd:________ Date:_______

STD CALCULATION FOR PSV SIZING

PRESSURE SAFETY VALVE SIZING CALCULATIONS VAPOUR OR GAS RELIEF 3

B ASED ON VOLUMETRIC FLOW RATE (Nm /m in)

12-Jun-13

PROCESS DATA Vapour or Gas Relief Fluid Relieving Scenario Vessel Design Code Required Flow through the device , V Nm3/min Gas Molecular Weight, M kg/kmol Relief Temperature of Inlet Gas or Vapor, T °C Compressibility, Z Cp/Cv , k RV Set pressure kPag Back Pressure, P2 kPag Back Pressure Correction Factor Kb (Default value = 1) Coefficient determined from an expression of the ratio of the specific heats (k = CP/Cv) , C Accumulation / Overpressure . CALCULATIONS / RESULTS Absolute Upstream Relieving Pressure. P1

1.908333333 29.00 75.00 1.00 1.400 1100.00 0.00 1.00

%

1432.33

kPaa

756.67 Critical Flow Conventional 0.975

Calculated Orifice Area, A

inch2

0.02538171064686

Self Chk:________ Date:________

inch2 Nm3/min

lb/hr. R

User Input for Kb (Optional).

.

21

kPaa

Preliminary PSV Size (Inlet x Outlet) Orifice Designation

627

356.06

Critical backpressure , Pcr Critical flow / Subcritical flow Type of SV Effective coefficient of Discharge, Kd Selected Orifice Selected Orifice Area Relieving Capacity of Selected PSV

4.207154833

D 0.110 8

Note, do not exceed defaults.

Default Value as per API-520. 0.000039342 mm2 Refer Table 1 of API Std. 526 Nm3/hr.

496.223

1"x 2" D

Chkd:________ Date:_______

Apprvd:________ Date:_______