fundamentals of hydrogen safety engineering 1

Vladimir Molkov Fundamentals of Hydrogen Safety Engineering I Download free eBooks at bookboon.com Fundamentals of Hydrogen Safety Engineering I © 2012 Vladimir Molkov & bookboon.com (Ventus Publishing ApS) ISBN 978-87-403-0226-4 Download free eBooks at bookboon.com Fundamentals of Hydrogen Safety Engineering I Contents Contents Introduction 1.1 Why hydrogen? 1.2 Public perception of hydrogen technologies 1.3 he importance of hydrogen safety 10 1.4 Hazards, risk, safety 13 1.5 Hydrogen safety communication 15 1.6 he subject and scope of hydrogen safety engineering 16 1.7 he emerging profession of hydrogen safety engineering 17 1.8 Knowledge gaps and future progress 20 Hydrogen properties and hazards 22 2.1 Physical and chemical properties 23 2.2 Combustion properties 35 2.3 Comparison with other fuels 47 2.4 Health hazards 53 2.5 Concluding remark 55 e Graduate Programme for Engineers and Geoscientists I joined MITAS because I wanted real responsibili Maersk.com/Mitas Real work International Internationa al opportunities work ree wo or placements Month 16 I was a construction supervisor in the North Sea advising and helping foremen he ssolve problems Download free eBooks at bookboon.com Click on the ad to read more Fundamentals of Hydrogen Safety Engineering I Contents Regulations, codes and standards and hydrogen safety engineering 56 Hydrogen safety engineering: framework and technical subsystems 63 4.1 Framework 63 4.2 Technical sub-systems 66 Unignited releases 67 5.1 Expanded and under-expanded jets 67 5.2 Under-expanded jet theories 70 5.3 he similarity law for concentration decay in momentum-dominated jets 76 5.4 Concentration decay in transitional and buoyancy-controlled jets 92 Dispersion of hydrogen in conined space 96 6.1 Dispersion of permeated hydrogen in a garage 97 6.2 he pressure peaking phenomenon 114 Ignition of hydrogen mixtures 125 7.1 Overview of hydrogen ignition mechanisms 125 7.2 Spontaneous ignition of sudden releases 131 Microlames 163 8.1 Quenching and blow-of limits 164 www.job.oticon.dk Download free eBooks at bookboon.com Click on the ad to read more Fundamentals of Hydrogen Safety Engineering I Contents Jet ires 171 9.1 Introduction to hydrogen jet ires and safety issues 171 9.2 Chronological overview of hydrogen jet lame studies 174 9.3 he drawback of Froude-based correlations 187 9.4 he similitude analysis and a dimensional correlation 188 9.5 he jet lame blow-of phenomenon 193 9.6 he novel dimensionless lame length correlation 195 9.7 Flame tip location and equivalent unignited jet concentration 200 9.8 Separation distances from a hydrogen leak 202 9.9 Efect of nozzle shape on lame length 206 9.10 Efect of jet attachment of lame length 207 9.11 Pressure efects of hydrogen jet ires 208 9.12 Summary 214 10 Delagrations Part II 10.1 General features of delagrations and detonations Part II 10.2 Some observations of DDT in hydrogen-air mixtures Part II 10.3 Vented delagrations Part II 10.4 Large eddy simulation (LES) of large-scale delagrations Part II Download free eBooks at bookboon.com Click on the ad to read more Fundamentals of Hydrogen Safety Engineering I Contents 11 Detonations Part II 11.1 Direct initiation of detonation Part II 11.2 LES of hydrogen-air detonations Part II 12 Safety strategies and mitigation techniques Part II 12.1 Inherently safer design of fuel cell systems Part II 12.2 Mitigation of release consequences Part II 12.3 Reduction of separation distances for high debit pipes Part II 12.4 Mitigation by barriers Part II 12.5 Mitigation of delagration-to-detonation transition (DDT) Part II 12.6 Prevention of DDT within a fuel cell Part II 12.7 Detection and hydrogen sensors Part II Concluding remarks Part II Acknowledgements Part II Appendix Glossary Part II References Part II Join the Vestas Graduate Programme Experience the Forces of Wind and kick-start your career As one of the world leaders in wind power solutions with wind turbine installations in over 65 countries and more than 20,000 employees globally, Vestas looks to accelerate innovation through the development of our employees’ skills and talents Our goal is to reduce CO2 emissions dramatically and ensure a sustainable world for future generations Read more about the Vestas Graduate Programme on vestas.com/jobs Application period will open March 2012 Download free eBooks at bookboon.com Click on the ad to read more Fundamentals of Hydrogen Safety Engineering I Disclaimer Author does not make any warranty or assumes any legal liability or responsibility for the accuracy, completeness, or any third party’s use of any information, product, procedure, or process disclosed, or represents that its use would not infringe privately owned rights Any electronic website link in this book is provided for user convenience and its publication does not constitute or imply its endorsement, recommendation, or favouring by the author Download free eBooks at bookboon.com Fundamentals of Hydrogen Safety Engineering I Introduction Introduction High priority research directions for the hydrogen economy include safety as a technological, a psychological and sociological issue (US Department of Energy, 2004) his book provides the state-ofthe-art in hydrogen safety as a technological issue and introduces a reader to the subject of hydrogen safety engineering Hydrogen safety engineering is deined as application of scientiic and engineering principles to the protection of life, property and environment from adverse efects of incidents/accidents involving hydrogen he use of hydrogen as an energy carrier presents several unusual hazards he best investment in hydrogen safety is educated and trained personnel, informed public his book is a contribution to hydrogen safety knowledge transfer and education of all stakeholders including technology developers and safety engineers, consultants and users, policy makers and investors, etc It can be used as a textbook for higher education programmes in hydrogen safety, e.g MSc in Hydrogen Safety Engineering course at the University of Ulster 1.1 Why hydrogen? he scarcity of fossil fuel reserves, geopolitical fears associated with fossil fuel depletion, and issues of environment pollution and climate change as well as the need to ensure independence of energy supply make the low-carbon economy with an essential hydrogen vector inevitable in the coming decades Today irst series of hydrogen-fuelled buses and cars are already on the road and refuelling stations are operating in diferent countries around the world How safe are hydrogen technologies and fuel cell products? his book will help to understand the state-of-the-art in hydrogen safety engineering and assist to make this fast emerging market inherently safer Global fuel cell demand will reach $8.5 billion in 2016 (PennWell Corporation, 2007) 1.2 Public perception of hydrogen technologies Public perception of hydrogen technologies is still afected by the 1937 Hindenburg disaster he catastrophe is oten associated with hydrogen as a reason even there is an opinion that the diference in electrical potential between the zeppelin “landing” rope and the ground during descending had generated electrical current that ignited the dirigible canopy made of extremely combustible material his was followed by difusive combustion of hydrogen in air without generation of a signiicant blast wave able to injure people Figure 1–1 shows a photo of burning Hindenburg dirigible ire demonstrating that there was no “explosion” (Environmental graiti alpha, 2010) Download free eBooks at bookboon.com Fundamentals of Hydrogen Safety Engineering I Introduction Figure 1–1 Photo of the Hindenburg dirigible ire demonstrating that there was no “explosion” (Environmental graiti alpha, 2010) Contrary to popular misunderstanding hydrogen helped to save 62 lives in the Hindenburg disaster he NASA research has demonstrated (Bain and Van Vorst, 1999) that the disaster would have been essentially unchanged even if the airship were lited not by hydrogen but by non-combustible helium, and that probably nobody aboard was killed by a hydrogen ire he 35% who died were killed by jumping out, or by the burning diesel oil, canopy, and debris (the cloth canopy was coated with what nowadays would be called rocket fuel) he other 65% survived, riding the laming dirigible to earth as the clear hydrogen lames swirled harmlessly above them 1.3 The importance of hydrogen safety here is a clear understanding by all stakeholders of the role of hydrogen safety for emerging hydrogen and fuel cell technologies, systems and infrastructure his is supported by investment to safety of about 5–10% of the total funding of hydrogen and fuel cell programmes both in USA and in Europe Hydrogen safety studies were initiated decades ago as a result of accidents in the process industries, and were supported by safety research for nuclear power plants and aerospace sector For example, a study of the hree Mile Island nuclear plant (USA) accident in 1979 (Henrie and Postma, 1983) demonstrated that almost homogeneous 8% by volume of hydrogen in air mixture delagrated Fortunately, the delagration pressure increases to about 190 kPa only that was considerably below the strength of the large concrete containment building Recent disasters involving hydrogen, i.e the Challenger Space Shuttle explosion (1986) and the Fukushima nuclear tragedy (2011), demonstrated that our knowledge and engineering skills to deal safely with hydrogen even within these industries require more investment, from both intellectual and inancial perspective Download free eBooks at bookboon.com 10 [...]... bookboon.com 33 Fundamentals of Hydrogen Safety Engineering I Hydrogen properties and hazards For example, it is equal to Z =1. 01 at 1. 57 MPa, Z =1. 1 at 15 .7 MPa, and Z =1. 5 at 78.6 MPa (temperature 293 .15 K) his means that at storage pressure of 78.6 MPa the amount of released hydrogen would be overestimated by 50% if the ideal gas equation of state is applied for carrying out hydrogen safety engineering. .. Liquid para -hydrogen (NBP) has a density of 70.78 kg/m3 he corresponding speciic gravity is 0.0 71 (the reference substance is water with speciic gravity of 1) hus, liquid hydrogen is approximately 14  times less dense than water Ironically, every cubic meter of water (made up of hydrogen and oxygen) contains 11 1 kg of hydrogen whereas a cubic meter of liquid hydrogen contains only 70.78 kg of hydrogen. .. that of liquid oxygen at its NBP Gas constant of hydrogen is 4 .12 43 kJ/kg/K (this is the universal gas constant divided by the molecular mass) he speciic heats ratio of hydrogen at NTP conditions (293 .15 K and 10 1.325 kPa) is g =1. 39 and STP conditions (273 .15 K and 10 1.325 kPa) is g =1. 405 hermal conductivity of hydrogen is signiicantly higher than that of other gases Gaseous hydrogen (W/m/K): 0 .18 7... Commission and the Fuel Cell and Hydrogen Joint Undertaking 1. 6 The subject and scope of hydrogen safety engineering he subject of hydrogen safety engineering (HSE) is deined as the application of scientiic and engineering principles to the protection of life, property and environment from adverse efects of incidents/accidents involving hydrogen he scope of hydrogen safety engineering is relected in the... speed of sound equation can be rewritten as C= g R ⋅T M (2 11 ) Download free eBooks at bookboon.com 34 Click on the ad to read more Fundamentals of Hydrogen Safety Engineering I Hydrogen properties and hazards Speed of sound in gaseous hydrogen is 12 94 m/s at NTP and 355 m/s at NBP (normal boiling point – boiling temperature of hydrogen 20.3 K at pressure 10 1,325 Pa) Speed of sound in liquid hydrogen. .. case of a delagration, which is in the range 0 .1- 10% and in most cases below 1% of the total energy of released hydrogen (Lind, 19 75; BRHS, 2009) his makes safety considerations of hydrogen accident with large inventory at the open quite diferent from that of other lammable gases with oten less or no harmful consequences at all Download free eBooks at bookboon.com 27 Fundamentals of Hydrogen Safety Engineering. .. of 10 1,325 kPa) of hydrogen is 20.3 K he normal melting point is 14 .1 K (10 1,325 kPa) Hydrogen has the second lowest boiling and melting points of all substances (helium has lowest value of boiling temperature of 4.2 K and melting temperature of 0.95 K) All these temperatures are extremely low and below the freezing point of air It is worth reminding that at absolute zero temperature of 0 K (–273 .15 .. .Fundamentals of Hydrogen Safety Engineering I Introduction Nowadays dealing with hydrogen is getting out of hands of highly trained professionals in industry and become everyday activity for public his implies a need in establishment of a new safety culture in society, development of innovative safety strategies and breakthrough engineering solutions It is expected that the level of safety and... course in hydrogen safety, i.e MSc in hydrogen safety engineering at the University of Ulster (http://www.ulster.ac.uk/elearning/ programmes/view/course /10 139), continuous professional development course at Warsaw University of Technology, hydrogen technology and safety course at the HECTOR School of the Karlsruhe Institute of Technology he main contributor to the establishment of the profession through... on the ad to read more Fundamentals of Hydrogen Safety Engineering I Hydrogen properties and hazards 2 .1 Physical and chemical properties 2 .1. 1 Atomic and molecular hydrogen, ortho- and para -hydrogen Atomic number of hydrogen (symbol H) in the periodic table is one, and atomic mass is 1. 008 g/mol (approximated by four digits) he hydrogen atom is formed by a nucleus with one unit of positive charge (proton) ... Hazards, risk, safety 13 1. 5 Hydrogen safety communication 15 1. 6 he subject and scope of hydrogen safety engineering 16 1. 7 he emerging profession of hydrogen safety engineering 17 1. 8 Knowledge... bookboon.com Fundamentals of Hydrogen Safety Engineering I Contents Contents Introduction 1. 1 Why hydrogen? 1. 2 Public perception of hydrogen technologies 1. 3 he importance of hydrogen safety 10 1. 4 Hazards,... 0.68 16 8.35 (G) 0 .19 6 32. 81 (STP) 1, 100 (300 K) 0.0977 15 .19 8 (STP) g/mol Hydrogen (H2) Methane (CH4) 2. 016 16 .043 70.78 (L, NBP) 13 2.0 (L, NBP) 1. 312 (G, NBP) 89.48 (G, NTP) 0.0838 (G, NTP) 11 .28