This document discusses stresses in pressure vessels. It describes how cylindrical pressure vessels experience circumferential, axial, and radial stresses. Thick cylinders have non-uniform stress distributions while thin cylinders have uniform stresses. Materials like carbon steel, stainless steel, and alloys are used in pressure vessels depending on factors like strength, corrosion resistance, cost and fabrication ease. Welded joints must meet ASME BPV Code standards. Failure analysis theories include maximum principal stress, maximum shear stress, and maximum strain energy.

1. (06-12-2k17)

2. MNS UTE MULTAN
Presented By ; Abdul Hannan
Muhhamad Asif
Presented To; Eng : Muhammad Aon Ali
Topic ; pressure vessels &
stresses produces in it
(06-12-2k17)
(2016-2020)
(semester 3rd)
Department of Mechanical Engineering
Technology

3. Cylinder
• Cylinder is a mechanical device used for
storing ,receiving processing the fluid.
Cylinder may be:
1. Pressure vessel
2. Storage vessel
3. Pipe
4. Engine cylinder

4. Pressure vessel
• Pressure vessel are
container or pipe line for
storing , receiving or
carrying the fluids under a
pressure.
1 Unfired pressure vessel
are: storage vessel
,reaction vessel , heat
exchanger , evaporator
2 Other: Steam boiler,
nuclear pressure vessel

5. Manufacturing Process
• Forming
• Pressing
• Spinning
• Bending
• Welding
• Post weld heat treatment (PWHT)
• Assembling
• Painting

6. Shape of Pressure vessel
Main components
• Shell
• Head
• Nozzle
• Support

8. Vessel Orientation
• Usually vertical
– Easier to distribute fluids
across a smaller cross section
– Smaller plot space
• Reasons for using horizontal
vessels
– To promote phase separation
• Increased cross section =
lower vertical velocity =
less entrainment
• Decanters, settling tanks,
separators, flash vessels
– To allow internals to be pulled
for cleaning
• Heat exchangers

9. Common types of P.V
1 Process pressure vessels:
In which specific process being done.
2 Heat exchanger pressure vessels:
Those where heat energy exchanges with
energy optimization.

10. Types of
Process pressure vessels
1 Column pressure vessel
2 Reactor pressure vessel
3 Gravity separator pressure vessel
4 Drums

11. Column pressure vessel

12. Reactor pressure vessel

13. Gravity separator pressure vessel

14. Drums

15. Drums

16. Geometric based types
1 Spherical pressure vessel
2 Cylindrical pressure vessel

17. Spherical pressure vessel

18. Spherical pressure vessel
layout

19. Spherical separator schematic

21. Cylindrical pressure vessel

22. Cylindrical pressure vessel

23. Applications
• Industrial compressed air receiver.
• Domestic hot water tank.
• Diving cylinder.
• Recompression camber.
• Distillation tower.
• Oil refineries and petrochemical plant.
• Nuclear reactor .
• Rail road industry.
• Storage for gasses and liquids .

24. Stresses in cylinder
• a stress distribution
with rotational
symmetry that is,
which remains
unchanged if the
stressed object is
rotated about some
fixed axis.

25. Cylinder stress patterns include
1 Circumferential stress or hoop stress:
a normal stress in the tangential direction.
2 Axial stress:
a normal stress parallel to the axis of
cylindrical symmetry.
3 Radial stress:
a stress in directions coplanar with but
perpendicular to the symmetry axis.

26. Stress in Thin Cylinder

27. Stress in Thin Cylinder

29. Stress in Thick cylinder

31. Some Maximum Allowable Stresses
Under ASME BPV Code Sec. VIII D.1, Taken
From Sec. II Part D
Material Grade Min Tensile Min Yield Maximum Maximum allowable stress at temperature F
strength strength temperature (ksi = 1000 psi)
(ksi) (ksi) (ºF) 100 300 500 700 900
Carbon steel A285 45 24 900 12.9 12.9 12.9 11.5 5.9
Gr A
Killed carbon A515 60 32 1000 17.1 17.1 17.1 14.3 5.9
Steel Gr 60
Low alloy steel A387 60 30 1200 17.1 16.6 16.6 16.6 13.6
1 ¼ Cr, ½ Mo, Si Gr 22
Stainless steel 410 65 30 1200 18.6 17.8 17.2 16.2 12.3
13 Cr
Stainless steel 304 75 30 1500 20.0 15.0 12.9 11.7 10.8
18 Cr, 8 Ni
Stainless steel 347 75 30 1500 20.0 17.1 15.0 13.8 13.4
18 Cr, 10 Ni, Cb
Stainless steel 321 75 30 1500 20.0 16.5 14.3 13.0 12.3
18 Cr, 10 Ni, Ti
Stainless steel 316 75 30 1500 20.0 15.6 13.3 12.1 11.5
16 Cr, 12 Ni, 2 Mo

32. Materials Selection Criteria
Safety
Material must have sufficient strength at design
conditions
Material must be able to withstand variation (or
cycling) in process conditions
Material must have sufficient corrosion resistance to
survive in service between inspection intervals
Ease of fabrication
Availability in standard sizes (plates, sections, tubes)
Cost
Includes initial cost and cost of periodic replacement

33. Commonly Used Materials
• Steels
– Carbon steel, Killed carbon steel – cheap, widely available
– Low chrome alloys (<9% Cr) – better corrosion resistance
than CS, KCS
– Stainless steels:
• 304 – cheapest austenitic stainless steel
• 316 – better corrosion resistance than 304, more
expensive
• 410
• Nickel Alloys
– high temperature oxidizing environments
– expensive, but high corrosion resistance, used for strong
acids
• Other metals such as aluminum and titanium are used for
special applications. Fiber reinforced plastics are used for some
low temperature & pressure applications. See Ch 7 for more
details

34. Type of Welded Joints in
pressure vessel
• Some weld types are not
permitted by ASME BPV Code
• Many other possible variations,
including use of backing strips
and joint reinforcement
• Sec. VIII Div. 1 Part UW has
details of permissible joints,
corners, etc.
• Welds are usually ground smooth
and inspected
– Type of inspection depends on
Code Division

35. Failure of Materials
Failure of materials under combined tensile and shear
stresses is not simple to predict. Several theories have
been proposed:
• Maximum Principal Stress Theory
– Component fails when one of the principal stresses
exceeds the value that causes failure in simple
tension
• Maximum Shear Stress Theory
– Component fails when maximum shear stress
exceeds the shear stress that causes failure in simple
tension
• Maximum Strain Energy Theory
– Component fails when strain energy per unit volume
exceeds the value that causes failure in simple
tension

36. END