STATE OF THE ART AND RESEARCH PRIORITIES IN HYDROGEN SAFETY

Wide spread deployment and use of hydrogen and fuel cell technologies can occur only if hydrogen safety issues have been addressed in order to ensure that hydrogen fuel presents the same or lower level of hazards and associated risk compared to conventional fuel technologies. To achieve this goal, hydrogen safety research should be directed to address the remaining knowledge gaps using risk-informed approaches to develop engineering solutions and Regulation Codes and Standards (RCS) requirements that meet individual and societal risk acceptance criteria, yet are cost-effective and market-competitive. IA HySafe and JRC IET partnered to organize a Research Priorities Workshop in Berlin on October 16-17, 2012 hosted by BAM (on behalf of IA HySafe) to address knowledge gaps in CFD modelling of hydrogen safety issues. The findings of the workshop are described in the report. The document aims to become a reference document for researchers/scientists and technical (including industry) experts working in the area worldwide. It is also a welcomed contribution for the Fuel Cell and Hydrogen Joint Undertaking (FCH JU) and for other funding bodies/organizations that must make decisions on research programmes and during the selection/choice of projects to be financially supported pursuing the safe use of hydrogen within Horizon 2020 framework.JRC.F.2-Energy Conversion and Storage Technologie

Fire performance of residential shipping containers designed with a shaft wall system

seven story building made of shipping containers is planned to be built in Barcelona, Spain. This study mainly aimed to evaluate the fire performance of one of these residential shipping containers whose walls and ceiling will have a shaft wall system installed. The default assembly consisted of three fire resistant gypsum boards for vertical panels and a mineral wool layer within the framing system. This work aimed to assess if system variants (e.g. less gypsum boards, no mineral wool layer) could still be adequate considering fire resistance purposes. To determine if steel temperatures would attain a predetermined temperature of 300-350ºC (a temperature value above which mechanical properties of steel start to change significantly) the temperature evolution within the shaft wall system and the corrugated steel profile of the container was analysed under different fire conditions. Diamonds simulator (v. 2020; Buildsoft) was used to perform the heat transfer analysis from the inside surface of the container (where the fire source was present) and within the shaft wall and the corrugated profile. To do so gas temperatures near the walls and the ceiling were required, so these temperatures were obtained from two sources: (1) The standard fire curve ISO834; (2) CFD simulations performed using the Fire Dynamics Simulator (FDS). Post-flashover fire scenarios were modelled in FDS taking into account the type of fuel present in residential buildings according to international standards. The results obtained indicate that temperatures lower than 350ºC were attained on the ribbed steel sheet under all the tested heat exposure conditions. When changing the assembly by removing the mineral wool layer, fire resistance was found to still be adequate. Therefore, under the tested conditions, the structural response of the containers would comply with fire protection standards, even in the case where insulation was reduced.Postprint (published version

Industrial Explosions Modelling; Special Case An Lpg Explosion

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2007Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2007Bu çalışmada endüstride en sık karşılaşılan iki patlama türü yer almaktadır. Bunlar gaz ve toz patlamalarıdır. Toz patlamaları ile ilgili, tarihte meydana gelen toz patlamaları, toz patlama beşgeni, toz patlamalarını tetikleyen etkenler, birincil ve ikincil toz patlamaları, toz patlama mekanizması ve toz patlama şiddetini etkileyen faktörler özetlenmiştir. Sonraki bölümde gaz patlamaları yer almaktadır. Sınırlı gaz patlamaları, kısmi sınırlı gaz patlamaları, kuşatılmamış gaz patlamaları, BLEVE olayı ve buhar bulutu yayılım modelleri açıklandı. Ayrıca mevcut gaz patlama modelleri incelenerek, bunların zayıf ve güçlü noktaları özetlendi. İncelenen gaz patlama modelleri sırası ile amprik modeller, fenomen modeller, CFD modelleri ve gelişmiş CFD modelleridir. Yine aynı bölümde mevcut gaz modelleme yazılımları özetlenmiştir. Uygulama bölümünde bir LPG dolum tesisinde meydana gelebilecek çeşitli kaza ve patlama senaryoları modellendi, ayrıca İTÜ Maslak kampüsünde bulunan LPG tankın kaza ve patlama senaryosu için modelleme yapıldı. Modelleme için ALOHA programı kullanılmıştır. Son bölümde endüstride patlama modellemelerinin kullanılmasının sağladığı faydalar ve bundan sonraki çalışmalar için bilgiler verildi.In this study the two main hazards in industry are discussed; gas explosions and dust explosions. In the first part dust explosion case history, the dust explosion pentagon, what triggers dust explosions, primary and secondary dust explosions, dust explosion mechanism, and the dust explosability factors are summarized. In the next part the gas explosions are presented. Confined gas explosions, partially confined gas explosions, unconfined gas explosions, BLEVE and vapour cloud dispersion models are presented. The current gas explosion models which are empirical models, phenomenological models, CFD models and advanced CFD models are summarised with their strong and weak points. Modelling software is presented. An experimental study was done at the LPG filling station and LPG storage tank at the İTÜ Maslak campus. The experimental chapter contains different simulation scenarios for failure and explosion of LPG tanks. Modelling was done by ALOHA program. Last chapter contains advantages of using explosion modelling in industry and recommendation for future work.Yüksek LisansM.Sc

Methodology Options for Hydrogen Safety Analysis

Master's thesis in Risk ManagementThe development of applications using hydrogen as a clean energy carrier has increased in recent years. Hydrogen is versatile and can be used in a wide range of applications. Hydrogen is already being widely used as a chemical feedstock for producing fertilizers and petrochemicals. Hydrogen can be used to power vehicles and generate heat and electricity. A prerequisite for commercial applications of hydrogen is to ensure that the risk associated with its production, storage, transport and use is at least not significantly higher than that of existing fuels. Hydrogen is not inherently more dangerous than other conventional fuels, but it has quite different properties, namely very low ignition energy, wide flammability range, high laminar burning velocity and high buoyancy. Consequence analysis is a critical part of any Quantitative Risk Assessment (QRA), which is used to predict the physical effects of the accidental release of flammable materials. A wide range of consequence analysis tools exist, ranging from simple integral tools based on empirical correlations to sophisticated three-dimensional Computational Fluid Dynamics (CFD) tools. Integral tools are easy to use and require less computational time; however, they take limited account of the influence of obstacles on the flow. Whereas CFD tools are more complex and require longer computational time (typically hours or day) and more skills, but they can predict the effect of complex geometries on the flow. Despite the intrinsic differences, CFD tools and integral tools are considered to perform the same task in consequences analysis. Uncertainties are always part of any consequence analysis, especially for emerging applications. Thus, it is important to understand the underlying assumptions and inherent limitations of the available tools, as well as the expected level of accuracy in the results for different types of hazardous scenarios. This study examines and compares the results predicted by the CFD tool (FLACS) and integral tools (FRED, PHAST and EFFECTS) which are used in hydrogen safety studies. The focus is to show where the tools predict similar results and where their results deviate strongly. It includes a description of the physical models used in FLACS, FRED, PHAST and EFFECTS for release modelling of hydrogen gas leak through an orifice from a pressurized storage tank. Release and dispersion simulations are carried out in each of FRED, EFFECTS, PHAST and FLACS for 81 hypothetical hydrogen gas release scenarios in open flat terrain. Then, sensitivity analysis is performed with variations in input parameters such as orifice size, wind speed, release direction, atmospheric stability class and surface roughness length to study their effect on the dispersion of the gas cloud. Finally, dispersion simulations are carried out in FLACS for hydrogen gas release from a dispenser in a refuelling gas station and its corresponding release scenario in open flat terrain to study the effect of obstacles on the dispersion of the gas cloud. A comparison tool was developed using the results produced by the four tools for 72 hydrogen gas release scenarios. The comparison includes the mass flow rate, the downwind distances to lower flammability limit (LFL) and half of lower flammability limit (½ LFL), and the amount of flammable mass between upper and lower flammability limits. The results showed that FLACS, FRED, EFFECTS and PHAST predicted almost the same mass flow rates for hydrogen gas released at 5 bar and 25 bar; however, FLACS predicted higher mass flow rates compared to the other tools for hydrogen gas released at 350 bar. The results of the dispersion simulations conclude that EFFECTS is not recommended for hydrogen safety studies due to the large discrepancies in the results when compared to FLACS, FRED and PHAST. FLACS predicted longer downwind distances to LFL and ½ LFL, and larger amount of flammable mass for most of the considered release scenarios; however, the results need to be compared against experimental results as it is not possible to recommend the use of one tool over the other based only on the results of this study. Hydrogen buoyancy does not prevent the formation of a large flammable cloud. The common argument is that a release of hydrogen gas in an unconfined area will rise and disperse relatively quickly upon release; however, this is not always the case. Hydrogen buoyancy is only valid outside the part of dispersion which is controlled by the jet momentum. From the results, a higher initial pressure produces a jet with higher momentum and the buoyancy force takes longer to dominate the flow. Also, hydrogen gas releases near the ground, tend to deflect towards the ground and cling to it because of an effect known as the Coandă effect. The results showed that this effect increases with the increase in wind speed. Obstacles in the path of the gas cloud help in decreasing the jet momentum and allow the buoyancy to have more effect; however, a large flammable cloud can still be formed

LNG annotated bibliography

This document updates the bibliography published in Liquefied Gaseous Fuels Safety and Environmental Control Assessment Program: third status report (PNL-4172) and is a complete listing of literature reviewed and reported under the LNG Technical Surveillance Task. The bibliography is organized alphabetically by author

Spacecraft Fire Safety 1956 to 1999: An Annotated Bibliography

Knowledge of fire safety in spacecraft has resulted from over 50 years of investigation and experience in space flight. Current practices and procedures for the operation of the Space Transportation System (STS) shuttle and the International Space Station (ISS) have been developed from this expertise, much of which has been documented in various reports. Extending manned space exploration from low Earth orbit to lunar or Martian habitats and beyond will require continued research in microgravity combustion and fire protection in low gravity. This descriptive bibliography has been produced to document and summarize significant work in the area of spacecraft fire safety that was published between 1956 and July 1999. Although some important work published in the late 1990s may be missing, these citations as well as work since 2000 can generally be found in Web-based resources that are easily accessed and searched. In addition to the citation, each reference includes a short description of the contents and conclusions of the article. The bibliography contains over 800 citations that are cross-referenced both by topic and the authors and editors. There is a DVD that accompanies this bibliography (available by request from the Center for Aerospace Information) containing the full-text articles of selected citations as well as an electronic version of this report that has these citations as active links to their corresponding full-text article

Bibliography of Lewis Research Center technical publications announced in 1986

This compilation of abstracts describes and indexes the technical reporting that resulted from the scientific and engineering work performed and managed by the Lewis Research Center in 1986. All the publications were announced in the 1986 issues of Scientific and Technical Aerospace Reports (STAR) and/or International Aerospace Abstracts (IAA). Included are research reports, journal articles, conference presentations, patents and patent applications, and theses

Aeronautical Engineering: A continuing bibliography with indexes (supplement 175)

This bibliography lists 467 reports, articles and other documents introduced into the NASA scientific and technical information system in May 1984. Topics cover varied aspects of aeronautical engineering, geoscience, physics, astronomy, computer science, and support facilities

Alternative Fuels for Transportation

Exploring how to counteract the world's energy insecurity and environmental pollution, this volume covers the production methods, properties, storage, engine tests, system modification, transportation and distribution, economics, safety aspects, applications, and material compatibility of alternative fuels. The esteemed editor highlights the importance of moving toward alternative fuels and the problems and environmental impact of depending on petroleum products. Each self-contained chapter focuses on a particular fuel source, including vegetable oils, biodiesel, methanol, ethanol, dimethyl ether, liquefied petroleum gas, natural gas, hydrogen, electric, fuel cells, and fuel from nonfood crops

Aeronautical Engineering: A continuing bibliography with indexes, supplement 107

Reports, articles, and other documents introduced into the NASA scientific and technical information system in February 1979 are listed in this bibliography