Hydrogen Safety for Energy Applications: Engineering Design, Risk Assessment, and Codes and Standards

Front Cover
Hydrogen Safety for Energy Applications
Copyright Page
Contents
List of contributors
Preface
1 Hydrogen fundamentals
	1.1 Physical properties of hydrogen
	1.2 Chemical properties of hydrogen
	1.3 Physiological hazards associated with hydrogen
	1.4 Influence of hydrogen on materials
	1.5 Environmental impact of hydrogen in the atmosphere
	1.6 Hydrogen properties
	References
2 Hydrogen technologies
	2.1 History and potential future of hydrogen technologies
	2.2 Hydrogen production processes
		2.2.1 Introduction
		2.2.2 Hydrocarbon splitting processes
			2.2.2.1 Steam reforming
			2.2.2.2 Partial oxidation
			2.2.2.3 Autothermal reformation
			2.2.2.4 Pyrolysis
			2.2.2.5 Safety challenges with hydrocarbon-based hydrogen production
		2.2.3 Water splitting processes
			2.2.3.1 Electrolysis
			2.2.3.2 Alkaline electrolysis
			2.2.3.3 Polymer membrane electrolysis
			2.2.3.4 High-temperature electrolysis
			2.2.3.5 Safety challenges with electrolysis
			2.2.3.6 Thermochemical (hybrid) cycles
			2.2.3.7 Safety challenges with chemical cyles
		2.2.4 Hydrogen cleaning processes
			2.2.4.1 Pressure swing absorption
			2.2.4.2 Membrane separation
			2.2.4.3 Cryogenic separation
		2.2.5 Hydrogen liquefaction
			2.2.5.1 Linde−Hampson process
			2.2.5.2 Claude process
			2.2.5.3 Magnetic refrigeration process
			2.2.5.4 Real world implementation
			2.2.5.5 Safety issues
		2.2.6 Large scale versus small scale and centralized versus decentralized production
	2.3 Hydrogen storage and transport
		2.3.1 Introduction
		2.3.2 Compressed gaseous storage
			2.3.2.1 Compression work
		2.3.3 Solid state storage
			2.3.3.1 Absorption process
			2.3.3.2 Desorption process
		2.3.4 Batch transport of hydrogen
		2.3.5 Transport using pipelines
		2.3.6 Future pathways and safety challenges
	2.4 Hydrogen energy conversion
		2.4.1 Introduction
		2.4.2 Combustion
			2.4.2.1 Internal combustion engines
			2.4.2.2 Gas turbines
		2.4.3 Fuel cells
			2.4.3.1 Thermodynamics and efficiencies of a fuel cell
			2.4.3.2 Fuel cell stack
			2.4.3.3 Fuel cell types
				2.4.3.3.1 Low temperature fuel cells
					Alkaline fuel cell
					Proton exchange membrane fuel cell (also polymer electrolyte fuel cell)
				2.4.3.3.2 Middle temperature fuel cells
					Phosphoric acid fuel cell
				2.4.3.3.3 High temperature fuel cells
					Molten carbonate fuel cell
					Solid oxide fuel cell
			2.4.3.4 Fuel cell systems
			2.4.3.5 Specific safety issues with fuel cells
	2.5 Hydrogen applications and their supply infrastructure
		2.5.1 Introduction
		2.5.2 Industrial applications
			2.5.2.1 Green ammonia production
			2.5.2.2 Green refinery
			2.5.2.3 Green steel
		2.5.3 Material handling
		2.5.4 Light duty and cars
			2.5.4.1 Light-duty vehicle refueling
			2.5.4.2 Safety issues with light duty and cars including the respective infrastructure
		2.5.5 Buses, heavy duty, and railways
			2.5.5.1 Buses
			2.5.5.2 Heavy-duty trucks
			2.5.5.3 Railway transport
			2.5.5.4 Safety issues with buses, heavy duty, and railways
		2.5.6 Maritime
			2.5.6.1 Bunkering
			2.5.6.2 Safety issues related to maritime applications
		2.5.7 Aircraft and space
		2.5.8 Portables
		2.5.9 Heat applications
			2.5.9.1 Safety issues related to heat applications
	2.6 Hydrogen systems major components
		2.6.1 Compressors
			2.6.1.1 Future pathways and safety issues of compressors
		2.6.2 Pressure vessels
			2.6.2.1 Specific safety aspects of automotive storage
		2.6.3 Large scale stationary storage containments
			2.6.3.1 Specific safety aspects
		2.6.4 Cryostats
			2.6.4.1 Safety challenges with cryostats
		2.6.5 Solid state storage systems
			2.6.5.1 Safety challenges with solid state storage systems
		2.6.6 Pipes and fittings
			2.6.6.1 Special pipes
		2.6.7 Valves
			2.6.7.1 Safety issues with valves
		2.6.8 Seals
	References
3 Phenomena relevant to accidents
	3.1 Hydrogen release
		3.1.1 Gaseous releases
			3.1.1.1 Permeation leaks
			3.1.1.2 Jets and plumes
			3.1.1.3 Subsonic and sonic jets
		3.1.2 Multiphase releases
			3.1.2.1 Two-phase jets
			3.1.2.2 Liquid H2 pool spreading and vaporization
	3.2 Hydrogen dispersion
		3.2.1 Hydrogen transport and mixing with air
			3.2.1.1 Molecular and turbulent mixing
		3.2.2 Dispersion in open environment
			3.2.2.1 Atmospheric turbulence
			3.2.2.2 Small releases
			3.2.2.3 Jet releases
			3.2.2.4 Liquid pool
			3.2.2.5 Catastrophic releases
		3.2.3 Dispersion in confined environment
			3.2.3.1 Natural and forced ventilation
			3.2.3.2 Nonuniformities in mixed distribution
	3.3 Hydrogen ignition
		3.3.1 Static electricity and electric spark
		3.3.2 Hot surface
		3.3.3 Mechanical friction and impact
		3.3.4 Miscellaneous
	3.4 Combustion of hydrogen
		3.4.1 Laminar premixed flames
			3.4.1.1 Structure of the reaction zone and flame temperature
			3.4.1.2 Dependence of laminar burning velocity on mixture composition, pressure, and temperature
		3.4.2 Turbulent premixed flames
			3.4.2.1 Turbulence scales
			3.4.2.2 Interaction between turbulence and flames: turbulent burning velocity
			3.4.2.3 Borghi diagram and interpretation of combustion regimes
		3.4.3 Laminar diffusion flames
		3.4.4 Turbulent diffusion flames
	3.5 Deflagration
		3.5.1 Deflagration basics
			3.5.1.1 Turbulence and deflagration speed
			3.5.1.2 Accelerated and fast deflagrations
		3.5.2 Deflagration in open atmosphere
		3.5.3 Confined deflagrations
			3.5.3.1 Deflagrations in tubes and in a system of connected vessels
			3.5.3.2 Amplification of pressure effect due to precompression (Mache effect)
		3.5.4 Vented deflagrations
			3.5.4.1 Multipeaks structure of pressure transients and underlying physical phenomena
	3.6 Transition from deflagration to detonation
		3.6.1 Phenomenology of flame acceleration and deflagration to detonation transition
		3.6.2 Effect of mixture and environmental properties
		3.6.3 Criteria for spontaneous flame acceleration to supersonic flame speed
		3.6.4 Criteria for establishment of stable detonation
	3.7 Detonation
		3.7.1 Detonation basics
			3.7.1.1 Detonation direct initiation
			3.7.1.2 Rankine−Hugoniot curve
			3.7.1.3 Chapman−Jouguet detonation
			3.7.1.4 Detonation limits
			3.7.1.5 Detonation front structure
			3.7.1.6 Detonation cell size
			3.7.1.7 Detonation stability. Steady and unsteady detonations
		3.7.2 Strategies in the detonation prevention
	References
4 Accident consequences
	4.1 Accident initiators
	4.2 Overpressure generation
		4.2.1 Physical explosions
		4.2.2 Boiling liquid expanding vapor explosion
		4.2.3 Chemical explosions
			4.2.3.1 Confined combustion
			4.2.3.2 Fast deflagration
			4.2.3.3 Detonation
			4.2.3.4 Vapor cloud explosion
			4.2.3.5 Real gas cloud behavior
			4.2.3.6 Documented release incidents
			4.2.3.7 Experimental work
			4.2.3.8 Modeling work
	4.3 Heat radiation generation
		4.3.1 Combustion characteristics of hydrogen
		4.3.2 Experimental studies of radiation
		4.3.3 Liquid hydrogen releases
	4.4 Infrastructure impact
		4.4.1 Heat radiation
			4.4.1.1 Interaction with objects
			4.4.1.2 Methods of determination of objects response
	4.5 Blast effects
		4.5.1 Debris and missiles
			4.5.1.1 The initial conditions
			4.5.1.2 The throw of debris and missiles
		4.5.2 Building structural response
			4.5.2.1 The initial diffraction loading
			4.5.2.2 The drag loading
			4.5.2.3 Confined areas
		4.5.3 Assessment of object responses
			4.5.3.1 Empirical methods—methods based on pressure peak values
			4.5.3.2 Methods based on P-I diagrams
			4.5.3.3 Analytical methods
			4.5.3.4 Dynamic load factor
			4.5.3.5 Single degree-of-freedom model
			4.5.3.6 Numerical methods
	4.6 Physiological impact
		4.6.1 Damage by low temperature releases
		4.6.2 Asphyxiation by hydrogen
		4.6.3 Human harm from blast
			4.6.3.1 Direct blast effects
			4.6.3.2 Indirect blast effects
		4.6.4 Thermal effects from fires
		4.6.5 Personal protective equipment
	4.7 Environmental impact
	References
5 Risk assessment
	5.1 Introduction
	5.2 Safety regulations and standards in different countries
	5.3 Safety management principles
	5.4 Risk-based safety management
	5.5 Assessing and profiling the risks
		5.5.1 Identifying risks
		5.5.2 What the law says on assessing risks
		5.5.3 Assessing the level of risk
			5.5.3.1 Small businesses
			5.5.3.2 Medium-sized businesses or those with greater risks
			5.5.3.3 Large and high-hazard sites
		5.5.4 The ALARP principle—As Low As Reasonable Practicable
		5.5.5 Quantitative risk assessment
		5.5.6 Risk assessment methodologies
		5.5.7 Risk assessment process
	5.6 Practical risk assessment
		5.6.1 Identifying the hazards
		5.6.2 Hazard identification methodologies
		5.6.3 Who might be harmed?
		5.6.4 Evaluate the risks
		5.6.5 Risk assessment methodologies
		5.6.6 Record your significant findings
		5.6.7 Regularly review your risk assessment
	5.7 Hydrogen hazards
		5.7.1 Thinking about the critical steps in an incident
		5.7.2 Safety principles to reduce or eliminate hazards
		5.7.3 Hazard estimation from modeling
	5.8 Learning from accident information
		5.8.1 Recent progress—hydrogen accident databases
			5.8.1.1 Hydrogen Incident and Accident Database
			5.8.1.2 H2Tools
	5.9 Modeling as a tool for QRA
		5.9.1 Key tenets of a QRA methodology
			5.9.1.1 Features of QRA
		5.9.2 Strengths and limits of QRA
		5.9.3 Examples—Application barriers, fault tree, event trees, and bow-tie diagrams
			5.9.3.1 Review of the preliminary risk analysis
			5.9.3.2 Applications involving high-pressure hydrogen storage
			5.9.3.3 List of initiating events
	5.10 Human factors
		5.10.1 Human factors and safety
		5.10.2 Human errors and organizational failures
		5.10.3 Human reliability assessment
		5.10.4 Safety culture
			5.10.4.1 Measuring safety culture/climate
	References
6 Safety measures and safety barrier functions
	6.1 Introduction to system safety
	6.2 Preventive and mitigative safety barrier functions
		6.2.1 System safety—what is safe enough?
	6.3 Inherently safe systems
		6.3.1 Avoiding risks/resilient systems
	6.4 Organizational and human factors
		6.4.1 Design and construction
		6.4.2 Safety procedures and training
	6.5 Relevant regulations and standards
		6.5.1 Generic measures
		6.5.2 The ATEX directives
		6.5.3 ISO/TR 15916:2015
		6.5.4 NFPA 2 “Hydrogen Technologies,” 2020 edition
		6.5.5 EIGA guidelines relevant for hydrogen safety barriers
		6.5.6 DNV hydrogen guideline documents
	6.6 Specific safety barriers in practice for hydrogen applications
		6.6.1 Detection of hydrogen releases
			6.6.1.1 Catalytic point detection
			6.6.1.2 Electrochemical detection
			6.6.1.3 Semiconduction oxide
			6.6.1.4 Thermal conductivity
			6.6.1.5 Mass spectrometer
			6.6.1.6 Acoustic detection
			6.6.1.7 Glow plugs
			6.6.1.8 Bubble testing
			6.6.1.9 Gas leakage detection by system monitoring
			6.6.1.10 Detection system guidelines
		6.6.2 Fire detection
		6.6.3 Layout considerations and explosion barriers
		6.6.4 Process control systems
		6.6.5 Emergency shutdown
		6.6.6 Natural and mechanical ventilation
			6.6.6.1 Natural ventilation
			6.6.6.2 Mechanical ventilation
			6.6.6.3 Ventilation considered in the ATEX directive 99/92/EC
		6.6.7 Draining and spill containment systems
		6.6.8 Ignition source control
		6.6.9 Inerting
		6.6.10 Blowdown and venting/flaring (safe burning)
		6.6.11 Passive fire protection
		6.6.12 Active fire protection
			6.6.12.1 Recombiner
		6.6.13 Explosion protection
			6.6.13.1 Enclosed areas
			6.6.13.2 Risk for DDT that can propagate into open areas
	6.7 Safety examples for hydrogen technologies
		6.7.1 Hydrogen fueling stations
		6.7.2 The Deep Purple project
		6.7.3 Hydrogen ferry in Norway
	6.8 Conclusion and current development
	Acknowledgements
	References
7 Legal requirements, technical regulations, codes, and standards for hydrogen safety
	7.1 Scope
		7.1.1 What does regulations, codes and standard mean?
		7.1.2 Elements of regulations, codes and standard terminology
		7.1.3 How this chapter refers to regulations, codes and standard documents
	7.2 The regulations, codes and standard international frame
		7.2.1 United Nations Regulations
		7.2.2 International standardization bodies
		7.2.3 Regulations, codes, and standards in the United States
		7.2.4 Regulations, codes, and standards in Canada
		7.2.5 Regulations, codes, and standards in Europe
			7.2.5.1 EU Regulations of relevance for hydrogen and fuel cell technology
			7.2.5.2 EU standardization frame of relevance for hydrogen
		7.2.6 Regulations, codes, and standards in Japan
		7.2.7 Regulations, codes, and standards in the People’s Republic of China
	7.3 General safety aspects
		7.3.1 Hydrogen-materials compatibility
		7.3.2 Hydrogen detection
		7.3.3 Liquid hydrogen
		7.3.4 Emergency responders
		7.3.5 Hydrogen systems in confined and semiconfined spaces
		7.3.6 Risk assessments
	7.4 Regulations, codes, and standards for specific hydrogen applications
		7.4.1 Hydrogen production
		7.4.2 Stationary applications
			7.4.2.1 Stationary fuel cell systems
			7.4.2.2 Stationary hydrogen storage
		7.4.3 Mobility and road transport
			7.4.3.1 Type approval of FCEV
			7.4.3.2 Hydrogen fueling stations
			7.4.3.3 Interoperability aspects (connection, communication, filling protocol)
			7.4.3.4 Heavy-duty transport
		7.4.4 Nonroad transport
			7.4.4.1 Industrial trucks
			7.4.4.2 Rails
			7.4.4.3 Waterborne sector
			7.4.4.4 Aviation
		7.4.5 Hydrogen–natural gas blends
			7.4.5.1 Injection of hydrogen into gas transport and distribution pipelines
			7.4.5.2 End uses of H2NG gas blends
		7.4.6 Hydrogen delivery
			7.4.6.1 Hydrogen transport by trailers
			7.4.6.2 Hydrogen transport by pipelines
			7.4.6.3 Hydrogen transport by ships
	7.5 Conclusions, gaps, bottlenecks, and future needs
	References
Index
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