Safety Valves in Oil and Gas Plants delivers a comprehensive overview of the various aspects of safety valves in the oil and gas industries, including their design and accessories. To help reinforce learning, case studies included throughout the text and multiple-choice questions and answers are included at the end of each chapter.
Written by an industry veteran with extensive publishing and speaking experience, this book includes information on: - Design details such as sizing and reaction forces, inspection, maintenance, codes and standards, and packing and preservation- Daily industrial challenges regarding the resizing of existing pressure safety valves (PSVs) or the proper sizing of new PSVs- Process safety standards for all new operative installations or existing ones in the chemical industry- Catalysts that can increase the pressure of fluids, including human error and equipment and component failure- The role of safety valves in protecting properties, the environment, and human life
This is an excellent reference on the subject for engineers and advanced students in chemical and process engineering, mechanical engineering, piping and valve engineering, and safety and instrument engineering.
Table of Contents
Preface ix
1 Basic Safety Valves Principles 1
1.1 Introduction and History 1
1.2 Maximum Allowable Working Pressure (MAWP) 2
1.3 The Importance of Safety Valves and Safety Devices 3
1.4 Overpressure Scenarios and Examples in the Plant 5
1.4.1 Closed Outlet of a Vessel 5
1.4.2 Unintentional Valve Opening 6
1.4.3 Check Valve Leakage or Failure 6
1.4.4 Utility Failure 6
1.4.5 Heat Exchanger Tube Failure 7
1.4.6 Transient Pressure Surges 7
1.4.7 Process Change/Chemical Reaction 8
1.4.8 Summary and Case Studies 8
1.5 Variations in Safety/Relief Valves 13
1.6 Safety Valve Parts 21
1.7 Safety Valve Dismantling 22
1.8 Basic Safety Valve Operation 23
1.9 Safety Valve Essential Pressure Settings 24
Questions and Answers 25
Further Reading 32
2 Design Fundamentals 33
2.1 Introduction 33
2.2 Spring Force 34
2.3 Back Pressure Consideration 35
2.3.1 Cold Differential Test Pressure 37
2.3.2 Superimposed and Dynamic (Buildup) Back Pressures 39
2.3.3 Back Pressure Handling and Safety Valve Selection 43
2.4 Overpressure and Blowdown 45
2.4.1 Safety Valve Functioning Curves 46
2.5 The Relationship Between the Pressure Values of Safety Valves and Pressure Vessels 49
2.6 Set Pressure Determination 52
2.7 Actual Discharge Area Calculation 55
2.8 Simmer 57
2.9 Pressure Loss in Inlet Piping 58
Questions and Answers 62
Further Reading 68
3 Safety Valves Features and Accessories 71
3.1 Introduction 71
3.2 Full Nozzle vs Seminozzle 72
3.2.1 Full-Nozzle Design 72
3.2.2 Seminozzle Design 75
3.3 Open vs Closed Bonnet 76
3.3.1 Open Bonnet Design 76
3.3.2 Closed Bonnet Design 77
3.4 Metal Seat vs Soft Seat 77
3.4.1 Metal Seat 77
3.4.2 Soft Seat 78
3.5 Bellows Seal 81
3.5.1 Bellows Effects 81
3.5.2 Bellows Failure Mechanisms 83
3.5.3 Bellows Failure (Leakage) Handling 85
3.5.4 Bellows Material Selection 88
3.5.5 Bellows Testing 89
3.6 Lifting Lever 92
3.7 Single vs Dual Trim 94
3.8 Wires 95
3.9 Test Gag 95
3.10 Low-Lift, High-Lift, and Full-Lift Disk 98
3.11 Balanced Piston 99
3.12 Cooling/Heating Spacer 100
3.13 Limit Switch (Position Indicator) 100
3.14 Pneumatic Actuator 100
3.15 Stroke Sensor 101
3.16 Pulsation Damper 102
3.17 Drain Hole 102
3.18 Teflon Lining and Coating 102
3.19 Stellite Coating on Seating Surfaces 103
Questions and Answers 104
Further Reading 113
4 Safety Valves Codes and Standards 115
4.1 Introduction 115
4.2 American Society of Mechanical Engineers (ASME) 116
4.3 American Petroleum Institute (API) 120
4.3.1 API Recommended Practice 520 Part 1: Sizing and Selection 121
4.3.2 API Recommended Practice 520 Part 2: Installation 123
4.3.3 API Recommended Practice 521 Pressure-Relieving and Depressuring Systems 124
4.3.4 API Recommended Practice 526 Flanged Steel Relief Valves 124
4.3.5 API Recommended Practice 527 Seat Tightness of Pressure-Relief Valves 124
4.3.6 API 576 Inspection of Pressure-Relieving Devices 125
4.4 International Organization for Standardization (ISO) 125
4.5 British Standards 127
4.6 Australian Standard 128
4.7 Canadian Standard 129
4.8 Other Standards 129
4.9 National Association of Corrosion Engineers (NACE) 129
4.10 Pressure Equipment Directive (PED) 130
4.11 Approval Authorities 131
Questions and Answers 132
Further Reading 137
5 Safety Valves Installation 141
5.1 Introduction 141
5.2 Prior to Installation 141
5.3 Location and Position 142
5.3.1 Distance to Pressure Source 143
5.3.2 Distance to Other Equipment 144
5.3.3 Inspection and Maintenance 145
5.4 Piping Connection 145
5.4.1 Inlet Piping 146
5.4.2 Inlet Valves 154
5.4.3 Outlet Piping 160
5.4.4 Outlet Valves 163
5.4.5 Piping Pressure Loss Calculations 166
Questions and Answers 175
Further Reading 184
6 Safety Valve Reaction Forces 187
6.1 Introduction 187
6.2 Calculations 187
Questions and Answers 201
Further Reading 203
7 Safety Valve Sizing 205
7.1 Introduction 205
7.2 Sizing for Gas or Vapor Relief 211
7.2.1 Critical Flow 211
7.2.2 Subcritical Flow 223
7.3 Sizing for Steam Relief 225
7.4 Sizing for Liquid Relief 229
7.4.1 Sizing for Liquid Relief With Capacity Certification 229
7.4.2 Sizing for Liquid Relief Without Capacity Certification 234
7.5 Sizing for Two-Phase Liquid/Vapor Relief 235
7.6 Sizing for Saturated Liquid and Saturated Vapor, Liquid Flashes 238
7.7 Sizing for Subcooled at the Pressure-Relief Valve Inlet 242
7.8 Sizing for Fire Case and Hydraulic Expansion 244
7.8.1 Hydraulic Expansion (Thermal Expansion) 246
7.8.2 Sizing Safety Valve for the Fire Case 247
Questions and Answers 254
Further Reading 256
Index 259
