Inspection Practices for Pressure Vessels

Downstream Segment

RECOMMENDED PRACTICE 572 THIRD EDITION, NOVEMBER 2009

Special Notes

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Copyright © 2009 American Petroleum Institute

Foreword

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Contents

Page

1. Scope 1

2. Normative References 1

3. Terms and Definitions 2

   1. Definitions 2

   2. Acronyms and Abbreviations 5

4. Introduction to Pressure Vessels 5

   1. General 5

   2. Methods of Construction 6

   3. Materials of Construction 6

   4. Internal Components and Equipment 7

   5. Uses of Pressure Vessels 8

   6. Design and Construction Standards 9

5. Reasons for Inspection 12

   1. General 12

   2. Safety 15

   3. Reliability and Efficient Operation 15

   4. Regulatory Requirements 15

6. Inspection Plans 15

   1. General 15

   2. Inspection for Specific Types of Damage 16

   3. Developing Inspection Plans 16

   4. RBI 17

7. Frequency and Extent of Inspection 17

   1. General 17

   2. Opportunities for Inspection 18

8. Safety Precautions and Preparatory Work 18

   1. Safety Precautions 18

   2. Preparatory Work 19

9. Inspection Methods and Limitations 21

   1. General 21

   2. Thickness Measurements 22

   3. External Inspection 24

   4. Internal Inspection 33

   5. Special Methods of Detecting Mechanical Damage 46

   6. Metallurgical Changes and In-situ Analysis of Metals 46

   7. Testing 47

10. Condition Assessment and Repair 50

    1. General 50

    2. Visual Inspection 50

    3. Thickness Measurements 51

    4. Remaining Life 51

    5. Methods of Repair 51

    6. Repair of Supporting Vessel Equipment 53

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11. Records and Reports 53

    1. Records 53

    2. Reports 53

Annex A (informative) Exchangers 54

Annex B (informative) Towers 71

Annex C (informative) Sample Record Forms 124

Figures

1. Type 316 Stainless-clad Vessel 7

2. Weld Metal Surfacing 8

3. Strip-lined Vessel 8

4. Principal Strip-lining Methods 9

5. Hex Mesh Installation for Refractory Lining 9

6. Reinforced Refractory 10

7. Vertical Heat Exchanger 11

8. Horizontal Vessel 12

9. Spheres 13

10. Horton Spheroid (Noded) 13

11. Process Tower 14

12. Exchangers 14

13. Exchanger Installation and Foundation 25

14. Severe Deterioration of Anchor Bolts 27

15. Method of Obtaining Vessel Profile Measurements 32

16. Corrosion in Channel 35

17. Crack in Weld Seen by PT 37

18. Hydrogen Blistering 38

19. Self-vented Hydrogen Blisters 39

20. Radiograph of Self-vented Hydrogen Blisters in Carbon Steel 39

21. Catalytic-reactor Internals—Cyclones 41

22. Corrosion Tab Method of Determining Metal Loss on Vessel Linings 43

23. Strip-liner Deterioration 44

24. Deteriorated Refractory-tile Lining 45

25. Steps in Using Special Equipment to Test Individual Tubes 49

1. Properly Rolled Tube 55

2. Tube-bundle Type of Tank Heater 57

3. Air-cooled Exchangers 58

4. Clean-service Double-pipe Coils 59

5. Tank Suction Heater with Everything but Forward End Enclosed; Shell Suction Nozzle

   Enclosed in Far End 60

6. Fin-type Tubes in Double-pipe Coil 60

7. Plate-type Exchanger 61

8. Tubes Thinned at Baffles 61

9. Tubes Fretting at Baffles 62

10. Erosion-corrosion Attack at Tube Ends 63

11. Heat Exchanger Parts 66

12. Heat Exchanger Types 70

1. Typical Trays in a Tower 71

2. Random Packing in a Tower 71

3. Trays with Downcomers 72

4. Bubble Cap Flow Path. 72

5. Tower Stripping and Rectification Section 73

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6. Disk/Donut Tray 74

7. Baffle Tray Arrangement 76

8. Sieve Tray 77

9. Sieve Tray Distortion 78

10. Typical Trayed Tower. 79

11. Float Valves with Two Weights 80

12. Fixed Valves 80

13. Bubble Cap Valves 81

14. Extruded Valves 81

15. New Floating Valve Tray 82

16. Caged Valves 82

17. Typical Packed Tower Drawing 83

18. Random Packing, Pall Rings 84

19. Structured Packing 84

20. Grid-style Packing 85

21. Diagram of Required Scaffolding 87

22. Hexagonal Manways 88

23. Standing Oil and Water 88

24. Trays Collapsed 89

25. Corroded Anchor Bolting 89

26. Corroded Anchor Bolting 90

27. Cracked and Bulged Fireproofing 90

28. Debris in Skirt 91

29. Preliminary Inspection 91

30. Bed Damage at Preliminary Inspection 92

31. Manway Corrosion 92

32. Manway Liner Damage 92

33. Corrosion on Gasket Seating Surface 93

34. Corrosion on Gasket Seating Surface 93

35. Surface Corrosion of Shell 94

36. Inspection From the Bottom Head 95

37. Inspection of Packing via Riser 95

38. Demister Bypass Deposits 95

39. Fouled Demister Pads 96

40. Faulty Demister Installation 96

41. Preferential Corrosion of the Head to Shell Weld 97

42. Head Seam Preferential Corrosion 97

43. Preferential Corrosion of the Shell 98

44. Perforation Degradation 98

45. Chimney Tray Deformation at Draw Sump 98

46. Fouled Troughs on Box and Trough Distributor 99

47. Obstructed Pipe Distributor Perforations 99

48. Box and Troughs 99

49. Hit the Washers, Not the Bolts 100

50. Random Packing on Valve Tray 100

51. Bed Limiter Above Random Packing 101

52. Dislodged Packing 101

53. Damaged Packing Support Grid 102

54. Support Grid from Below 102

55. Corrosion Inside Sightglass Nozzle 103

56. Bottom Head, Vortex Breaker, and Debris 103

57. Fouled Grid-type Packing 104

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58. Cracked Plug Weld 104

59. Stainless Steel Donut Cladding Breech 105

60. Cladding Breech at Gouges in Bottom Head 105

61. 410 Stainless Steel Clad to Carbon Steel Interface Weld 106

62. Supplemental UT Markings 106

63. Cracking at Tray Support Ring Weld 107

64. WFMPT Discovered Cracking 108

65. Supplemental NDE May be Needed 108

66. Areas of Chemical Activity 109

67. Areas of Activity 109

68. Hardware Corrosion 110

69. Stuck Valves Always Open 110

70. Clean Square-edged Perforation 111

71. Valve Fretting 111

72. Slotting from Below 111

73. Valve Leg and Perforation Inspection 112

74. Indentation of Valves 112

75. New Caged Valves with Dimples 113

76. New Caged Valve Cage Tabs 113

77. Small Fixed Valves 114

78. Fixed Valves Lateral Vapor Directional Flow 114

79. Removable Fixed Valves Reduce Fouling 115

80. Removable Fixed Valves Tray Damage 115

81. Bubble Caps on Stepped Trays 116

82. Fibrous Deposits and Fouling Under Bubble Caps 116

83. Tray Deck Should be Scraped Clean 117

84. Tray Fatigue Cracking 117

85. Light-to-moderate Weir Corrosion. 118

86. Loose and Missing Hardware Failure 118

87. Downcomer and Seal Pan Clamps Loose 119

88. Downcomer Clamp Loose 119

89. Tray Support Ring Corroded to Failure 120

90. Deposits Adjacent to Shell are on Ring 120

91. Shell Corroded to Half Wall Adjacent Top Three Rings 121

92. Support Ring Grooving 121

93. Cracking of Ring Attachment Weld 121

94. Tray Support Ring Butt Weld Cracking 122

95. Breeching of the Seal Weld 122

96. Shadowing Inside the Downcomer 123

97. Shadow the Downcomer Shell Every Tray 123

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Inspection Practices for Pressure Vessels

1. Scope

   This recommended practice (RP) covers the inspection of pressure vessels. It includes a description of the various types of pressure vessels (including pressure vessels with a design pressure below 15 psig) and the standards for their construction and maintenance. This RP also includes reasons for inspection, causes of deterioration, frequency and methods of inspection, methods of repair, and preparation of records and reports. Safe operation is emphasized within this RP.

   
   

2. Normative References

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

API 510, Pressure Vessel Inspection Code: In-service Inspection, Rating, Repair, and Alteration

API Recommended Practice 571, Damage Mechanisms Affecting Fixed Equipment in the Refining Industry

API Recommended Practice 574, Inspection Practices for Piping System Components

API Recommended Practice 575,Guidelines and Methods for Inspection of Existing Atmospheric and Low-pressure Storage Tanks

API Recommended Practice 576, Inspection of Pressure-Relieving Devices

API Recommended Practice 577, Welding Inspection and Metallurgy

API 579-1/ASME FFS-1 1, Fitness-For-Service

API Standard 660, Shell-and-Tube Heat Exchangers

API Standard 661, Air-Cooled Heat Exchangers for General Refinery Service

API Recommended Practice 945, Avoiding Environmental Cracking in Amine Units

API Publication 2214, Spark Ignition Properties of Hand Tools

API Publication 2217A, Guidelines for Safe Work in Inert Confined Spaces in the Petroleum and Petrochemical Industries

ASME Boiler and Pressure Vessel Code (BPVC), Section VIII: Pressure Vessels

ASME PCC-2, Repair of Pressure Equipment and Piping

NB-23 2, National Board Inspection Code

TEMA 3, Standards of Tubular Exchanger Manufacturers Association

1. ASME International, 3 Park Avenue, New York, New York 10016, www.asme.org.

2. National Board of Boiler and Pressure Vessel Inspectors, NBBI, 1055 Crupper Avenue, Columbus, Ohio 43229, www.nationalboard.org.

3. Tubular Exchanger Manufacturers Association, 25 North Broadway, Tarrytown, New York 10591, www.tema.org.

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