INDEX

SECTION PAGE

COVER PAGE

CERTIFICATE

ACKNOWLEDGEMENTi

ii

iii

LIST OF FIGURESvi

LIST OF TABLESvii

LIST OF SYMBOLSviii

ABSTRACTix

1. Introduction1

2. Classification of pressure vessel2

3. Pressure vessel codes and standards3

4. Main components of pressure vessel4.1. Shell

4.2. Head

4.3. Nozzle

4.4. Support4

5

6

7

8

5. Stress in shell

5.1. Stresses in thin shell

5.1.1. Cylindrical vessel under internal pressure

5.1.2. Spherical vessel under internal pressure

5.1.3. Conical shell under internal pressure

5.2. Stresses in thick cylinder9

10

10

12

12

14

6. Materials for pressure vessel

6.1. Yield strength

6.2. Ductility and toughness

6.3. Available materials

6.4. Environmental factor

6.4.1. Physical properties of metals at elevated temperatures

6.4.2. Hydrogen embrittlement of pressure vessel steels18

18

19

20

21

21

22

7. Autofrettage23

8. Economics of pressure vessel and design

8.1. Material cost

8.2. Fabrication methods2324

26

9. Pressure vessel company in India26

10. Inspection techniques26

11. Future aspects/ Recent Developments27

References29

LIST OF FIGURES

FIGUREPAGE NO.

1. Main components of pressure vessel

2. Various shapes of shell

3. Different types of head

4. Thin cylindrical pressure vessel

5. Stresses in pressure vessel shell

6. Longitudinal stress in thin cylindrical shell

7. Circumferential stress in thin cylindrical shell

8. Radial stress in thin cylindrical shell

9. Hoop stress in spherical thin walled pressure vessel

10. Stresses in a conical vessel

11. Stresses in thick cylinder

12. Variation of principal stresses

13. Effect of temperature on stress-strain relationship of mild carbon steel

14. Material comparative stress-cost index5

5

7

9

9

10

11

11

12

12

15

16

22

25

LIST OF TABLE

TABLEPAGE NO.

1. Metal temperature operating limits for carbon-molybdenum steels in contact with steels

2. Relative fabrication cost factor for several commonly used pressure vessel material23

25

LIST OF SYMBOLS

E Youngs modulus

G Shear modulus

R radius

t thickness

semi vertex angle

linear strain

shear strain

Poissons ratio

Normal stress

Shear stress

L longitudinal stressr radial stress

h hoop stress

deflection

Do outer radius

Di inner radius

P internal gauge pressure

ABSTRACT

This report includes comprehensive discussion on pressure vessel technology, an emerging field. Discussion is focussed on components of pressure vessels, its design and various stresses occurring in the pressure vessel, and pressure vessel design for various types of shell thickness and shapes. A brief review of codes and standards for the pressure given by American Society of Mechanical Engineers (ASME) is also included. Further a brief introduction of autofrettage is also given in the report.The important factors to be considered in the selection of suitable materials for pressure vessel are also described. These factors include strength, toughness and environmental factors. A brief review of the materials currently available is also included, along with the discussion of hydrogen embrittlement.This report also tries to shed some light on economical considerations in pressure vessel design including relative material cost factor as well as fabrication methods. Inspection Techniques are also discussed in brief along with recent developments in this field.1. INTRODUCTION

Vessels, tanks and pipelines that carry, store, or receive fluids are called pressure vessels. A pressure vessel is defined as a container with a pressure differential between inside and outside. The inside pressure is usually higher than the outside, except for some isolated situations. The fluid inside the vessel may undergo a change in state as in the case of steam boilers, or may combine with other reagent as in case of a chemical reactor. Pressure vessels often have a combination of high pressures together with high temperatures, and in some cases flammable fluids or highly radioactive materials. Because of such hazards it is imperative that the design be such that no leakage can occur. In addition these vessels have to be designed carefully to cope with the operating temperature and pressure. It should be borne in mind that the rupture of a pressure vessel has a potential to cause extensive physical injury and property damage. Plant safety and integrity are of fundamental concern in pressure vessel design and these of course depend on the adequacy of design codes. When discussing pressure vessels we must also consider tanks. Pressure vessels and tanks are significantly different in both design and construction: tanks, unlike pressure vessels, are limited to atmospheric pressure; and pressure vessels often have internals while most tanks do not( and those that do are limited to heating coils or mixers).Widely used in sectors as follows:

1. In power generation industry for fossil and nuclear power.2. In the petrochemical industry for storing and processing crude petroleum oil in tank farm and as storing gasoline in service station.

3. In chemical industries.

Generally speaking, pressurised equipment is required for a wide range of industrial plant for storage and manufacturing purposes.

2. CLASSIFICATION OF PRESSURE VESSELS1. Based on installation

i. Vertical

ii. Horizontal

2. Based on pressure bearing situation

i. Internal pressure vessel

ii. External pressure vessel

3. Based on wall thickness

i. Thin wall

ii. Thick wall

4. Based on manufacturing materials

i. Steel vessels

ii. Non-ferrous vessels

iii. Non-metallic vessels

5. Based on geometrical shapesi. Cylindrical vessels

ii. Spherical vessels

iii. Conical vessels

iv. Combined vessels

6. Based on operating temperature

i. Low temperature vessels(