Boiler Drum Thickness Calculation

DRUM THICKNESS CALCULATION - SA 516 GR. 70 (AS PER IBR) STEAM DRUM (SINGLE) Description Design pressure, Wp Maximum Working Temperature, T1 Metal Temperature, T2 = (T1) Drum I/D

Units Kg/cm^2 (g) °C °C °F mm

PREMISSIBLE WORKING STRESS (f) = Et / 1.5 Et = Yield Stress at Metal temperature (From ASME Section - II, Part D) Et = Yield Stress at Metal temperature (From ASME Section - II, Part D) f = Et / 1.5 Thickess of Drum Shell Provided, T1

psi Kg/cm^2 Kg/cm^2 mm

124 327 327 620.6 1372

page:16 page:507 Allo.Sress 28729 19153 2020.34 1346.89 1346.89 105

LIGAMENT EFFICIENCY (E) Longitudinal Ligament of main bank tubes = (p - d) / p

0.7504

MINIMUM THICKNESS Tmin, ((Wp x I/D) / (2 x f x E - Wp)) + 0.762

mm

90.43

thickness of shell (if >60mm) stress value reduction (>60mm)

mm %

45.00 9.00

Kg/cm^2 mm

1225.67 99.93

actual stress value Actual thickness,T2

2 % reducion in stress for every 10 mm increase in shell thickness

(Outside gas path) no need to add 28.4deg.c

Material : SA516 Gr.70 Carbon plate Metal temperature (deg.F) 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900 950 1000

Design Metal temperature (deg.F)

Allowable stress (psi) 20000 20000 20000 20000 20000 20000 20000 20000 20000 20000 19400 18800 18100 14800 12000 9300 6700 4000 2500

620.6 600 650

Allowable stress (psi)

19400 18800 19153

12 20.6

Metal temperature (deg.F) 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900 950 1000

Design Metal temperature (deg.F)

Yield stress (ksi) 38.00 35.70 34.80 34.20 33.60 33.05 32.50 31.75 31.00 30.05 29.10 28.20 27.20 26.30 25.50 24.70 24.00 23.30 22.60

620.6 600 650

Yield stress (psi)

29.1 28.2 28729

0.018 20.6