Overpressure Protection in the Process Industry: A Critical View

Front cover
Half title
Full title
Copyright
Contents
About the Author
Acknowledgments
Introduction
CHAPTER 1 - Studies on overpressure relief systems
1.1 Introduction
1.2 Factors of noncompliance
1.3 Leaking safety relief valves
1.4 Comments on a case study
1.4.1 Operational inspection
1.4.2 Inspection of valves
CHAPTER 2 - Background to pressure relief design
2.1 Introduction
2.2 Principles of pressure relief
2.2.1 General design philosophy
2.2.2 Key principles and design sequence
2.2.3 Safety and pressure relief alternatives
2.2.4 Recommended pressure relief stream design and documentation
CHAPTER 3 - Critical view on designing pressure safety devices according to PED, ASME, and ISO/EN or API
3.1 Introduction
3.2 Structure comparison of the codes
3.2.1 Harmonized European standards
3.2.1.1 Product standards
3.2.1.2 Application standards
3.2.2 The ASME code
3.3 Comparison of performance characteristics for pressure relief valves
3.3.1 Functional characteristics
3.3.2 Flow capacity comparisons
3.3.2.1 Determining discharge coefficient according to ASME
3.3.2.2 Discharge coefficient according to VdTüV 100 and TRD
3.3.2.3 Determining discharge coefficient according to EN/ISO 4126-1
3.4 Testing
3.4.1 According to European normalization
3.4.2 Tests to determine operating characteristics according to ASME
3.4.3 Valves used in the test programs
3.4.4 Sizing and spring setting according to EN/ISO 764-7
3.5 International harmonization
CHAPTER 4 - Keeping overpressure protection up to date
4.1 Influencing factors for overpressure protection change
4.2 Lifecycle management
4.2.1 Protecting safety relief valves with rupture discs
4.2.2 Cost of ownership and asset management
CHAPTER 5 - Management of change and pressure relief analysis
CHAPTER 6 - Codes, recommendations, and sizing methods
6.1 Introduction
6.2 US directives
6.3 European directives
6.4 Other worldwide directives
6.5 Other specific directives
6.6 Former directives and codes
CHAPTER 7 - Emergency depressurization valves versus pressure relief devices
7.1 Introduction
7.2 Pressure system safety regulations
7.3 Types of safety systems
7.3.1 The pressure control valves
7.3.2 The emergency shutdown and emergency depressurizing systems
7.3.3 The pressure relief devices
7.4 Safety instrumented systems and safety integrity levels
7.5 Design perspectives
7.6 Operational perspective
7.7 The bowtie analysis
7.8 Overall decision making
7.9 Taking overpressure scenarios to a layer of protection analysis
CHAPTER 8 - Process pressures
8.1 Introduction
8.2 Definitions, design, and sizing terms
8.3 The relief design procedure
CHAPTER 9 - Effects of backpressures on relief ­devices
9.1 Introduction
9.2 Types of backpressure
9.3 Safety relief valve selection
9.4 Sizing with backpressures
9.5 The issues with backpressure
CHAPTER 10 - Chatter in relief valves and the 3% rule
10.1 Introduction
10.2 Design effects on chatter
10.3 Types of chatter
10.4 The 3% rule: fiction or reality
CHAPTER 11 - Installation of pressure relief devices
11.1 Introduction
11.2 General installation recommendations
11.3 Types of discharge
11.3.1 Open discharge
11.3.2 Closed discharge
11.3.3 Exit conditions affecting hazard zones
11.4 Special code requirements
Chapter 12 - Overpressure scenarios
12.1 Introduction
12.2 Understanding overpressure scenarios
12.2.1 Role of the systems or process engineer in the PHA/LOPA
12.2.2 Using PRDs or independent protection levels in PHA/LOPA
12.2.3 Taking overpressure scenarios to a layer of protection analysis
12.2.4 PRDs used as an independent protection level
12.2.5 Risk reduction credits for overpressure scenarios
12.2.6 Overpressure IPL solutions other than PRDs
12.2.7 Double jeopardy in relief scenarios
12.3 Scenario calculations
12.3.1 Blocked discharge
12.3.1.1 Centrifugal pumps
12.3.1.2 Positive displacement pumps
12.3.1.3 Compressors and positive displacement blowers
12.3.2 Gas blowby
12.3.3 Fire case
12.3.3.1 Vaporizing liquids (wetted vessels)
12.3.3.2 Alternative method to determine pool fires
12.3.3.3 Vessels containing only vapor or gasses (unwetted vessels)
12.3.3.4 Differences in codes
12.3.4 Thermal effects—cooling or reflux failure
12.3.5 Thermal expansion
12.3.6 Chemical runaway reactions
12.3.7 Heat exchangers
12.3.7.1 Thermal expansion in heat exchangers
12.3.7.2 Tube rupture in heat exchangers
12.3.8 Equipment, instrument, or automatic control failure
12.3.9 Blocked filters and strainers
12.3.10 Utility or power failure
12.3.11 Entrance of volatile media or abnormal fluid input
12.4 Scenario examples
CHAPTER 13 - Recommended and generally accepted good engineering practices
CHAPTER 14 - Relief system sizing and design
14.1 Introduction
14.2 Use of shutdown devices
14.3 What do codes say?
14.4 Pros and cons of taking credit for emergency shutdown devices
14.5 Types of emergency shutdown devices
14.5.1 Safety instrumented systems
14.5.2 Auto lockout devices
14.5.3 Auto start devices
14.5.4 Shutdown systems for fired heaters
14.6 Various methods of credit taking
14.7 High integrity emergency shutdown devices versus reliability of pressure relief valves
CHAPTER 15 - Overpressure protection on low-pressure storage tanks
15.1 Introduction
15.2 Recommended guidelines and practices
15.3 Selecting conservation vents
15.4 Technology and principle of operation of conservation vents
15.5 Sizing for normal operation
15.6 Sizing for emergency relief
15.7 Setting conservation vents
15.7.1 Set pressure tolerances
15.7.2 Leakage tolerances
CHAPTER 16 - Tank blanketing
16.1 Introduction
16.2 Why and where to use tank blanketing
16.3 General description of the blanketing process
16.4 Types of blanketing systems
16.5 Sizing blanketing systems
16.5.1 Inbreathing requirements
16.5.2 Outbreathing requirements
16.6 Blanketing methods and requirements
16.7 Setting and use of blanketing systems
16.8 International guidelines and recommendations
CHAPTER 17 - Learning from accidents/incidents and study cases
17.1 Introduction
17.2 Accident 1: Texas city refinery explosion
17.3 Accident 2: hydrocracking unit UK
17.4 Accident 3: storage tank explosion
17.5 Accident 4: tank explosion
17.6 Accident 5: the Seveso disaster
17.7 Accident 6: LNG plant Russia
17.8 Accident 7: chemical runaway accident the United States
17.9 Accident 8: The Piper Bravo offshore rig
17.10 Miscellaneous accidents
17.11 Pressure relief case studies
17.11.1 New installations
17.11.2 Existing installations
17.12 Incidents due to small modifications
Abbreviations and acronyms
Further reading
Index
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