Safety Valve Sizing Calculations as Per IBR 1950

IBR CALCULATIONS

1. Safety Valve Capacity Calculations 1.1. Boiler Safety Valve

Pressure Part Membrane Panel Shell Nose wall Front Wall Total

Sr. No. 1 2 3 4

Heat Transfer Area 8 8 .9 3 7 1 .5 3 9 .5 1 7 .1 5 1 7 .0

m2 m2 m2 m2 m2

Required Safety Valve Capacity: Safety valve relief capacity= Heating Surface area X 30

:IBR regulation 293

Boiler Capacity (C) = Minimum Required Safety valve relief capacity on Shell as per heat transfer area (C1) =

18000 180 00 kg/hr kg/hr 15511 155 11 kg/hr kg/hr

Minimum Required Safety valve relief capacity on SH (25% of Total capacity) (C2) =

4500 4500 kg/h kg/hrr

Minimum Required Safety valve relief capacity on Shell (Maximum of (C C2) & C1))=

15511 155 11 kg/hr kg/hr

Actual Safety valve relief capacity: E=C X A X P - - - - - - Reg. 293

Safety Valve-1 Safety Valve-2 Total

Size 40 NB 40 NB

Orifice area, (A) cm2 6 .6 0 2 6 .6 0 2

Valve constant (C) 38 38

Margin over required capacity on Shell =

5

Set Pressure (P) in Bar ab. 32.39 32.39

Safety Valve Capacity (E) 8126 812 6 kg/hr kg/hr 8126 812 6 kg/hr kg/hr 16252 kg/hr

%

As the provided capacity of safety valves is greater than the required hence the provided safety valve capacity is adequate. D1= t1= d1= A1=

S Sttand Pipe outer Diameter in mm Thickness of Stand pipe in mm In I nternal Diameter of Stand pipe in mm 2 Cross sectional Area of stand pipe in mm 2 Cross sectional Area of stand pipe in cm

69 . 9 15. 9 38. 1 1139.51 11.40

As the provided stand pipe of safety valves is greater than the c/s area of orifice hence design is safe,

IBR CALCULATIONS

1. 2. Superheater Safety Valve E=C E=C X A X P / 1 + 2 2.7 .7 X De ree of Su erhea erheatt / 1000 1000

Safety Valve-3 Total

Size 40 NB

0.5

i n K /h r

Safety Valve Capacity Safety (E) at Valve Degree of Orifice area, Set Pressure Capacity at Superheat Superheat A cm2 Valve constant C P in Bar ab. saturated in deg. C ed Temp. 6 .6 0 2 38 30.910 7 75 5 80 7 03 2

Margin over required capacity on SH =

56

Total capacity of safety valves

=

2 3 28 4

kg/hr

=

2 9 .3 6

%

Margin Over the Maximum capacity required

%

As the total capacity of safety valves provided is greater than required capacity, hence safet valve selection is safe D1= t1= d1= A1=

Stand Pipe outer Diameter Diameter in mm Th T hickness of Stand pipe in mm Internal Diameter of Stand pipe in mm 2 Cross sectional Aerea of stand pipe in mm 2 Cross sectional Aerea of stand pipe in cm

48.3 Refer Drg No 0.508 Re R efer Drg No 4 7 .2 8 1755.08 17.55

As the provided stand pipe of safety valves is greater than the c/s area of orifice hence design is safe,