Article

Experimental determination of dust cloud deflagration parameters of selected hydrogen storage materials: Complex metal hydrides, chemical hydrides, and adsorbents

January 2013
Journal of Loss Prevention in the Process Industries 26(1):96–103

DOI:10.1016/j.jlp.2012.09.010

Authors:

Yale University

Experimental Determination of Dust Cloud Combustion Parameters of Alpha-AlH3 Powder in its Charged and Fully Discharged States for H2 Storage Applications

Article

Oct 2016
J LOSS PREVENT PROC

Yehia F. Khalil

Risk quantification framework of hydride-based hydrogen storage systems for light-duty vehicles (Y.F. Khalil, JLP, 2015)

Data

Full-text available

Nov 2015

Yehia F. Khalil

Risk quantification framework of hydride-based hydrogen storage systems for light-duty vehicles

Article

Sep 2015
J LOSS PREVENT PROC

Yehia F. Khalil

ABSTRACT This study aims to develop a quantitative risk assessment (QRA) framework for on-board hydrogen storage systems in light-duty fuel cell vehicles, with focus on hazards from potential vehicular collision affecting hydride-based hydrogen storage vessels. Sodium aluminum hydride (NaAlH4) has been selected as a representative reversible hydride for hydrogen storage. Functionality of QRA framework is demonstrated by presenting a case study of a postulated vehicle collision (VC) involving the onboard hydrogen storage system. An event tree (ET) model is developed for VC as the accident initiating event. For illustrative purposes, a detailed FT model is developed for hydride dust cloud explosion as part of the accident progress. Phenomenologically-driven ET branch probabilities are estimated based on an experimental program performed for this purpose. Safety-critical basic events (BE) in the FT model are determined using conventional risk importance measures. The Latin Hypercube sampling (LHS) technique has been employed to propagate the aleatory (i.e., stochastic) and epistemic (i.e., phenomenological) uncertainties associated with the probabilistic ET and FT models. Extrapolation of the proposed QRA framework and its core risk-informed insights to other candidate on-board reversible and off-board regenerable hydrogen storage systems could provide better understanding of risk consequences and mitigation options associated with employing this hydrogen-based technology in the transportation sector. Keywords: Event tree; fault tree; on-board reversible; off-board regenerable; dust cloud explosion; importance measures

Experimental investigation of the complex deflagration phenomena of hybrid mixtures of activated carbon dust/hydrogen/air

Article

Nov 2013
J LOSS PREVENT PROC

Yehia F. Khalil

This paper aims to develop quantitative insights based on measured deflagration parameters of hybrid mixtures of activated carbon (AC) dust and hydrogen (H-2) gas in air. The generated experimental evidence is used to reject the claim of the null hypothesis (H-0) that severity of deflagrations of H-2/air mixtures always bound the severity of deflagrations of heterogenous combustible mixtures of AC dust/H-2/air containing the same H-2 concentrations as in the H-2/air binaries. The core insights of this investigation show that the maximum deflagration pressure rise (Delta P-MAX) and maximum rate of pressure rise ((dP/dt)(MAX)) of this hybrid mixture are greater than those corresponding to deflagrations of H-2/air mixtures for all the dust and H-2 concentrations being examined. The deflagration severity indices (K-st and ES) of the hybrid mixture containing 29 M01% H-2 are found to be greater than those of the H-2/air mixture containing 29 mol% H-2. Also, the minimum explosible concentration (MEC) of the hybrid mixture is lower than that of the AC dust in air only. The insights gained should lead to better realization of the severity of a postulated safety-significant accident scenario associated with on-board cryadsorption H-2 storage systems for fuel-cell (FC) powered light-duty vehicles. The identified insights could also be relevant to other industrial processes where combustible dusts are generated in the vicinity of solvent vapors. Moreover, these insights should be useful for supporting quantitative risk assessment (QRA) of on-board H-2 storage systems, designing improved safety measures for cryoadsorption H-2 storage tanks, and guiding H-2 safety standards and transportation regulations.

Science-based framework for ensuring safe use of hydrogen as an energy carrier and an emission-free transportation fuel

Article

May 2018
PROCESS SAF ENVIRON

Yehia F. Khalil

The objective of this research is to examine the safety-related characteristics of candidate hydrogen storage materials being considered for use in light-duty fuel-cell vehicles (LD-FCV) under the U.S. Department of Energy (DOE) Hydrogen Program. This research aims to provide useful meaning to the general DOE safety target by establishing a link between the safety-related characteristics of candidate storage materials and satisfaction of DOE safety target. Accordingly, a science-based framework has been developed and consists of standardized materials tests (based on internationally accepted ASTM and United Nations testing protocols), novel risk mitigation strategies, and subscale system demonstration. The examined storage materials include NaAlH4, AlH3, 2LiBH4 + MgH2, 3Mg(NH2)2.8LiH, NH3BH3, and activated carbon (Maxsorb AX-21). The scope of safety tests covers conditions that the storage material may encounter during postulated accident scenarios such as dust cloud explosion, materials reactivity in air and other fluids, hot-surface contact, mechanical impact, and fast depressurization. The generated results uncovered potential fire and explosion risks under accidental conditions. The generated insights can be useful for assigning realistic probability values needed for quantifying risk scenarios, characterizing material’s hazard class, and supporting current and new hydrogen safety codes and standards. For risk mitigation, this study showed that powder compaction could be effective in suppressing pyrophoricity of hydride powders such as NaAlH4. Also, the study has experimentally demonstrated that adding (NH4)H2PO4 as a flame retardant to the hydride powder before compaction could suppress sensitivity of hydrides like NaAlH4 to ignite due to mechanical impact. The results also revealed that Maxsorb AX-21 to be a safer hydrogen storage medium compared to the examined hydrides which exhibited potential safety concerns under certain accident conditions.

Hydrogen Energy and Sustainable Development

Chapter

Full-text available

Jan 2023

Aisha H. Al-Moubaraki

Dust cloud explosion characteristics and mechanisms in MgH2‐based hydrogen storage materials

Article

Full-text available

May 2021
AICHE J

The mechanisms involved in premixed magnesium and hydrogen hybrid and synthetic MgH2 dust cloud explosions were investigated. The results revealed that trace amounts of H2 in Mg explosions can markedly increase explosion severity. Furthermore, H2 addition can weaken the influence of oxygen deficiency on Mg explosion. Moreover, the explosion intensity of synthetic MgH2 was far stronger than that of premixed Mg/H2 mixture or Mg alone because the vacancy defects in Mg and H atoms can form after dehydrogenation of MgH2, which caused that Mg and H2 are prone to oxidation and nitrification in air atmosphere at a low temperature, thereby promoting the explosion. This demonstrates that the explosion risk of MgH2 (even other H2 storage materials) is related to its H2 storage capacity and dehydrogenation temperature. Therefore, for H2 storage materials, the better H2 storage performances can exhibit higher explosion risks.

Catalytic Effect of Facile Synthesized TiH1.971 Nanoparticles on the Hydrogen Storage Properties of MgH2

Article

Full-text available

Sep 2019

Catalytic doping plays an important role in enhancing the hydrogen storage performance of MgH2, while finding an efficient and reversible catalyst remains to be a great challenge in enhancing the de/rehydrogenation properties of MgH2. Herein, a bidirectional nano-TiH1.971 catalyst was prepared by a wet chemical ball milling method and its effect on hydrogen storage properties of MgH2 was studied. The results showed that all the TiH1.971 nanoparticles were effective in improving the de/rehydrogenation kinetics of MgH2. The MgH2 composites doped with TiH1.971 could desorb 6.5 wt % H2 in 8 min at 300 °C, while the pure MgH2 only released 0.3 wt % H2 in 8 min and 1.5 wt % H2 even in 50 min. It was found that the smaller the size of the TiH1.971 particles, the better was the catalytic effect in promoting the performance of MgH2. Besides, the catalyst concentration also played an important role and the 5 wt %-c-TiH1.971 modified system was found to have the best hydrogen storage performance. Interestingly, a significant hydrogen absorption amount of 4.60 wt % H2 was evidenced for the 5 wt %-c-TiH1.971 doped MgH2 within 10 min at 125 °C, while MgH2 absorbed only 4.11 wt% hydrogen within the same time at 250 °C. The XRD results demonstrated that the TiH1.971 remained stable in cycling and could serve as an active site for hydrogen transportation, which contributed to the significant improvement of the hydrogen storage properties of MgH2.

Activated carbons from oil palm shell for hydrogen storage

Article

Full-text available

Jun 2018

Activated carbons (ACs) with controlled microporosity have been developed from oil palm shell and their H2 storage performances been have tested at 77 K. Such adsorbents are the natural agricultural by-products of chemically activated with KOH. N2 adsorption-desorption at 77 K was used to investigate the pore structure of the ACs produced with different weight ratio of KOH/oil palm shell charcoal. The results showed that the developed oil palm shell ACs achieved surface areas (SBET) as high as 3508 m²/g and micropores volumes (VDR) as high as 1.10 cm³/g. Outstanding storage capacities of hydrogen, as high as 6.8 wt.% have been obtained at 4 MPa and 2.86 wt.% have been obtained at 1 bar for some of these adsorbents at 77 K. These values of hydrogen adsorption are among the best that ever published so far, which well above those of some reference commercial materials, e.g. Maxsorb-3, and also the ACs from the open literature.

Experimental investigation into the vented hybrid mixture explosions of lycopodium dust and methane

Article

Dec 2017
J LOSS PREVENT PROC

Vented hybrid mixture explosions were conducted in a 20-L chamber with different venting diameters and static activation pressures. Simultaneously, the maximum explosion pressure and the maximum rate of pressure rise of hybrid mixtures were also determined. It was found that the addition of methane to lycopodium dust led to an increase in both the maximum explosion pressure and the maximum rate of pressure rise and a decrease in the optimum dust concentration. Both the maximum explosion pressure and the maximum rate of pressure rise of hybrid mixtures were higher than those of lycopodium dust, but lower than those of methane. Similarly, the addition of methane to lycopodium dust led to an increase in the maximum reduced pressure, and the maximum reduced pressure increased with increase of the methane concentration. This effect was more pronounced for small vents and high static activation pressures. The maximum reduced pressure of the hybrid mixture was higher than that of lycopodium dust, but lower than that of methane. This was consistent with the relationship of the maximum explosion pressure between the three different systems. However, the increase in the maximum reduced pressure of lycopodium dust taken by the additional methane was obviously higher than that in the maximum explosion pressure, indicating that the influence of methane on the maximum reduced pressure of lycopodium dust was more significant. Adding methane to lycopodium dust increased the longest vented flame length and decreased the duration time of the external flame. Similar to the maximum reduced pressure, the longest flame length of the hybrid mixture was longer than that of lycopodium dust, but shorter than that of methane. However, it is the converse for the duration time of the external flame.

Synthesis of Bamboo-Based Activated Carbons with Super-High Specific Surface Area for Hydrogen Storage

Article

Full-text available

Jan 2017
BIORESOURCES

Activated carbons (ACs) were developed from the agricultural by-products of moso bamboo by pyrolysis carbonization and the KOH activation process. N2 adsorption-desorption at 77 K, thermogravimetric analysis (TG), X-ray photoelectron spectrometry (XPS), element analysis (EA), X-ray diffraction (XRD), scanning electron microscopy (SEM), high- resolution transmission electron microscopy (HRTEM), and Fourier transform infrared spectroscopy (FTIR) were used to investigate the synthesis process, the impact of the weight ratio of KOH/bamboo charcoal (BC), and the characteristics of the bamboo charcoal and ACs produced. The results showed that the developed bamboo ACs achieved surface areas (SBET) as high as 3208 m2/g and micropores volumes (VDR) as high as 1.01 cm3/g. The carbonation and activation of the bamboo resulted in the enhancement of the microstructure of the bamboo ACs, and hence improvements in the sorption behavior and storage capacity. The highest hydrogen storage capacities achieved were 6.6 wt.% at 4 MPa and 2.74 wt.% at 1 bar, both at 77 K, which were much higher than those of a well-known commercial activated carbon.

Dust cloud combustion characterization of a mixture of LiBH4 destabilized with MgH2 for reversible H2 storage in mobile applications

Article

Oct 2014
INT J HYDROGEN ENERG

Yehia F. Khalil

This study discusses results of an experimental program to determine dust cloud combustion characteristics of 2LiBH4 + MgH2 binary system in air. The determined parameters of hydrided and partially-dehydrided states of this system include: maximum deflagration pressure rise (PMAX), maximum rate of pressure rise (dP/dt)MAX, minimum ignition temperature (TC), minimum explosible concentration (MEC), minimum ignition energy (MIE), and explosion severity index (KSt). Impact of dust particle size on the measured parameters is evaluated for the partially-dehydrided state. For dust of same mean particle size, results show the hydrided state to be more explosible in air compared to its partially-dehydrided state. Moreover, MIE of the partially-dehydrided mixture is identified in the test with lowest ignition delay time (IDT) and highest dust cloud concentration (DC). Taguchi's mixed-levels design of experiments (DoE) methodology is employed to calculate dust's MIE response surface as a function of DC and IDT. The one-at-a-time effect and interaction effect between DC and IDT on dust MIE are determined. The core insights of this contribution are useful for quantifying risks in mobile and stationary H2 storage applications, informing H2 safety standards, and augmenting property databases of H2 storage materials.

Exploring hydrogen storage safety research by bibliometric analysis

Article

Sep 2024
INT J HYDROGEN ENERG

Catalytic effects of magnesium-transition metal (Fe and Ni) hydrides on oxygen and nitrogen reduction: A case study of explosive characteristics and their environmental contaminants

Article

Oct 2023
ENERGY

The decomposition mechanism of ethylene and modeling simulation during LDPE production: A comprehensive review and perspectives

Article

Sep 2023
J ANAL APPL PYROL

Hydrogen Storage Challenge in the Hydrogen-Based Civilization

Chapter

Jun 2023

Industrial revolution and sustainable development have intensified the need for clean resources of energy. Among all the possible alternative sources of green energy, hydrogen energy is the most promising one because of its abundancy, maximum energy density per unit mass, and clean combustion. The energy content per unit mass of hydrogen is estimated to be the highest among all known chemical fuels. Therefore, it has enough potential to meet the rising energy demand if some major barriers in its production, storage, and effective commercial or vehicular use are resolved efficiently. One of the most significant challenges in the development of a global hydrogen-based economy is the hydrogen storage problem, which essentially means minimizing the enormous volume of hydrogen gas to achieve optimum gravimetric and volumetric density synergistically. This chapter briefly discusses the significant challenges, especially the hydrogen storage problem in the path of the development of a hydrogen-based economy and the possible approaches to meet the challenges.

Hydrogen Safety TASK 37- FINAL REPORT

Technical Report

Full-text available

Mar 2022

Yehia F. Khalil

This technical report on hydrogen safety (Task 37) of the Technical Collaboration Program (TCP), Internal Energy Agency (IEA) is comprised of five chapters as follows: Chapter 1: Task goal and objectives Chapter 2: Task member countries and organizational structure Chapter 3: Task main achievements, deliverables, and safety knowledge dissemination Chapter 4: Hydrogen safety and the path forward Chapter 5: Task 37 key messages and recommendations This technical report also has 3 appendices as follows: Appendix A: Task 37 website Appendix B: Hydrogen Safety Journal Appendix C: Examples of Task 37 annual meetings Task 37 provided the following key messages and recommendations for future hydrogen R&D activities: 1) Over its six-years duration, Task 37 provided key quantitative risk insights (both physics-based and probabilistic) to support the development of both new and revised hydrogen safety C&S (e.g., NFPA-2 and ISO standards). 2) Dr. Khalil emphasizes the importance of expanding the current scope of hydrogen safety beyond the hydrogen-powered light-duty electric vehicles (LDEV) application and H2 refueling stations. To this end, Dr. Khalil recommends expanding the scope of H2 safety to other applications such as maritime, commercial aviation (hybrid-electric & all-electric aircraft), power-to-gas (P2G), heavy-duty vehicles, trains, and H2 transport in long road tunnels and other confined-spaces such as garages. Accordingly, additional R&D efforts are needed to ensure the safety of emerging hydrogen-based technologies and associated infrastructures. 3) Bulk storage of hydrogen (whether as compressed gas or liquified) would require investigation of novel tanks design, materials selection, more robust risk mitigation and control methods, and H2 leakage detection devices. 4) Comprehensive safety-related research efforts are needed to address materials-compatibility issues associated with hydrogen. 5) Improved understanding of safety issues is needed with respect to separation distances (aka, setback distances or safety distances), underground and above-ground hydrogen storage, leakage of hydrogen from transport pipelines, injecting hydrogen gas in existing natural gas networks, risks associated with blending hydrogen with natural gas for domestic heating, etc. 6) Hydrogen production, transport & distribution, supply chains safety risks, infrastructure physical security and vulnerability assessment, as well as safety codes & standards continue to be central issues for achieving the desired economies of scale and reliable adoption of hydrogen-based technologies. 7) There is a need for harmonizing hydrogen safety codes & standards to remove (or at least lower) unnecessary regulatory barriers and to establish common standards that ensure safety in each stage of the hydrogen value chain. Achieving this goal will accelerate the deployment of at-scale hydrogen-based technologies. As a concluding remark on what Task 37 of the Hydrogen Technical Collaboration Program (H2 TCP) has accomplished over the past six years, Dr. Khalil emphasizes that: We must continue to seize all emerging opportunities to demonstrate, via science-based methods, the safety of hydrogen-based technologies. The author of this technical report is Dr. Y. F. Khalil, the Operating Agent (OA) and Manager of the Hydrogen Safety Task 37 (which started in January 2015 and ended in December 2021) of the International Energy Agency (IEA) headquartered in Paris, France.

UK Research and Innovation Hydrogen Experts Meeting

Presentation

Full-text available

May 2018

Yehia F. Khalil

Dr. Yehia F. Khalil delivered an invited lecture at the UK Research and Innovation - Hydrogen Experts Meeting, Department of Engineering Science, University of Oxford, UK. The meeting was held during the period May 22 – 23, 2018. In this lecture, Dr. Khalil presented his portfolio of R&D related to sustainable hydrogen production, life cycle assessment (LCA), and life cycle impact assessment (LCIA). He also provided an overview of the Task 37 (Hydrogen Safety) which he manages for the International Energy Agency (IEA), Hydrogen Technical Collaboration Program (H2 TCP). In this program, Dr. Khalil manages a portfolio of hydrogen R&D conducted by a group of H2 safety experts from several countries around the world including UK, France, Norway, Denmark, U.S., Canada, Japan, and China.

Safe use of hydrogen for on-board light-duty fuel cell vehicles (LD-FCV)

Presentation

Full-text available

Oct 2015

Yehia F. Khalil

Dr. Khalil, Operating Agent for the Hydrogen Safety Task of the International Energy Agency (IEA), discussed a framework comprised of standardized safety tests to assess the safe use of metal hydrides, chemical hydrides, and adsorbents as solid-state hydrogen storage media for on-board light-duty fuel cell vehicles. He also presented two baselines design for on-board hydrogen storage systems. The first design is for on-board reversible hydrogen storage and the second design is for off-board regenerable hydrogen storage.

Task 37: Hydrogen Safety, International Energy Agency (IEA)

Presentation

Full-text available

Jun 2016

Task 37 Hydrogen Safety

Presentation

Full-text available

Jun 2016

The effects of coal dust concentrations and particle sizes on the minimum auto‐ignition temperature of a coal dust cloud

Article

May 2017
FIRE MATER

Flash fires and explosions in areas containing an enriched combustible dust atmosphere are a major safety concern in industrial processing. An experimental study was conducted to analyse the effects of atmospheric coal dust particle sizes and concentrations on the minimum auto‐ignition temperature (MAIT) of a dust cloud. Two different coal samples from Australian coal mines were used. The coal dust particles were prepared and sized in 3 ranges, of below 74 μm, 74 to 125 μm and 125 to 212 μm, by using a series of sieves and a sieve shaker. A humidifier was used to increase the moisture content of the particles to the required level. All the experiments were conducted in accordance with the ASTM E1491‐06 method in a calibrated Goldbert‐Greenwald furnace. The results from this study indicate that coal dust properties, such as the chemical nature (H/C), concentration, particle size (D 50 ), and moisture content, impact on the MAIT. For coal dust concentrations less than 1000 g.m ⁻³ , the MAIT decreases with increasing coal dust concentrations. On the other hand, for low concentrations of 100 to 15 g.m ⁻³ , the MAIT becomes more reliable for particle size D 50 rather than for volatile matters.

Flow characteristics of dusts dispersed by high-pressure air blast in 20 L chamber

Article

May 2015
ENG COMPUTATION

Purpose – A dust cloud is formed by a high-pressure air blast in dust explosion experiments in the spherical 20 L chamber. The state of the dust cloud has a significant impact on the dust explosion. However, it is difficult to observe the dust distribution in the chamber during the dust dispersion. Numerical simulation was used to examine the dust distribution in the chamber with the rebound nozzle in this work. The paper aims to discuss these issues. Design/methodology/approach – Through a series numerical simulations, the influences of the dust particle size and the pressure for dust dispersion on the have been analyzed, and the results are discussed. Findings – Dust in the spherical 20 L chamber is in the state of very intensifying motion within 30 ms from dispersion starting. Dust in the chamber reaches a uniform state beyond 200 ms. The pressure for dust dispersion should be higher than 0.5 MPa for the aluminum dusts of larger than 50. The higher blast pressure is not always applicable to achieve a uniform dispersion. There is a best blast pressure value for a given dust to achieve a uniform dispersion in the spherical 20 L chamber. Research limitations/implications – Dust cloud generation is essential for understanding dust explosions. Dust cloud deflagration parameters depend on the uniformity and concentration of dusts dispersed by a high-pressure air blast. Numerical simulation was used to examine the multiphase flow of the dust air mixture in this work. Through a series numerical simulations, the influences of the dust particle size and the pressure for dust dispersion on the have been analyzed, and the results are discussed. The data are useful for understanding the basics of dust cloud formation. Practical implications – The data are useful for evaluating dust explosion experimental parameters. Originality/value – Dispersible uniformity has a strong impact on measured parameters of dust explosion in a chamber. However, it is difficult to observe the dust particles distribution during the dispersion. Numerical simulation was used to examine the dust particles distribution and its influencing factors during the dispersion in this work. New finding is: the approach to examine the distribution of dust particles dispersed by a high-pressure blast in a chamber; the variation of dispersible uniformity and its influencing factors when dust is injected into the spherical 20 L chamber by high-pressure air blast.

Flame behaviors and pressure characteristics of vented dust explosions at elevated static activation overpressures

Article

Nov 2014
J LOSS PREVENT PROC

Slurry-based chemical hydrogen storage systems for automotive fuel cell applications

Article

Nov 2014
J POWER SOURCES

In this paper, the system designs for hydrogen storage using chemical hydrogen materials in an 80-kWe fuel cell, light-duty vehicle are described. Ammonia borane and alane are used for these designs to represent the general classes of exothermic and endothermic materials. The designs are then compared to the USDRIVE/DOE-developed set of system-level targets for onboard storage. While most DOE targets are predicted to be achieved based on the modeling, the system gravimetric and volumetric densities were more challenging and became the focus of this work. The resulting system evaluation determined that the slurry accounts for the majority of the system mass. Only modest reductions in the system mass can be expected with improvements in the balance-of-plant components. Most of the gravimetric improvements will require developing materials with higher inherent storage capacity or by increasing the solids loading of the chemical hydrogen storage material in the slurry.

Quantifying and Addressing the DOE Material Reactivity Requirements with Analysis and Testing of Hydrogen Storage Materials and Systems

Conference Paper

Full-text available

May 2011

Yehia F. Khalil

The findings of this research both experimental and probabilistic modeling is part of this Principal Investigator (PI) project funded by the U.S. Department of Energy. Project title: Quantifying and Addressing the DOE Material Reactivity Requirements with Analysis and Testing of Hydrogen Storage Materials and Systems.

IV.E.1 Quantifying and Addressing the DOE Material Reactivity Requirements with Analysis and Testing of Hydrogen Storage Materials and Systems

Conference Paper

Full-text available

Jun 2011

Yehia F. Khalil

The key technical target of this project is EH&S, having a focus on the safety sub-target with some consideration for toxicity. The technical target for safety is specified generally as “Meets or exceeds applicable standards.” For metal hydride, chemical hydride and adsorbent materials and systems, however, no such standards exist today. Furthermore, standards currently under development will be high-level in scope, primarily focused on systems and will not provide adequate guidance for evaluating and selecting viable candidate materials. As part of this effort, trade-offs will be evaluated between residual risks after mitigation and the two technical barriers: (A) System Weight and Volume (E) Charging/Discharging Rates

Aluminium dust explosion risk analysis in metal workings

Article

Full-text available

Nov 2004
J LOSS PREVENT PROC

The aim of this paper is to present a risk analysis method that can be applied to factories where combustible dust is handled, in the form of raw materials, products or by-products, and therefore at risk to explosion. The work was carried out on site: a consistent number of companies that deal with the surface finishing of objects in aluminium through grinding were examined. The aluminium powder produced as a by-product is generally captured by suction plants and then subjected to dry or wet type abatement. In order to provide a rational approach to the risk assessment and frequency estimation, each company was divided into the so-called fields of study; and four risk assessment topics were identified for each field. A brief review of the methods that are available for the consequence magnitude estimation, regarding both the pressure wave and the launching of missiles, is also provided.

TESTING TO ASSESS EXPLOSION CHARACTERISTICS OF DUST CLOUDS

Article

Vahid Ebadat

A dust deflagration will occur if the concentration of the combustible dust that is suspended in air is sufficient to propagate flame when ignited by a sufficiently energetic ignition source. The oxygen in air is the most common oxidant however other oxidants such as fluorine, chlorine, and bromine can also be associated with deflagration events. The ignition sources that have been found to be the cause of the majority of explosions in dust handling/processing plants include (this is not an exhaustive list) hot work, open flames, mechanical friction and sparks, hot surfaces and equipment, thermal decomposition, electrical arcs (sparks), and electrostatic discharges. A systematic approach to identifying dust cloud explosion hazards and taking measures to ensure safety generally involves: Understanding the explosion characteristics of the dust(s) Identifying areas of the facility where combustible dust cloud atmospheres could exist under normal and/or abnormal conditions Identifying potential ignition sources that could exist under normal and/or abnormal conditions Taking measures to eliminate/control ignition sources, control the spread of combustible dust clouds, control oxidant supply (application of inert gas purging and/or padding); Taking measures to protect against the consequences of potential dust cloud explosions. Explosion protection measures include explosion relief venting, explosion suppression, explosion containment, and explosion isolation; and Regular inspection and maintenance of equipment and facilities to minimize ignition sources and dust releases As indicated above testing to characterize the powder's fire and explosion properties is an essential step in identifying potential ignition sources, assessing the risk and consequences

Combustible dust national emphasis program (reissued) Source

Jan 2008

Osha Directive

OSHA Directive. (2008). Combustible dust national emphasis program (reissued). Source. http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table¼DIRECTIV ES&p_id¼3830.

Imperial Sugar Company dust explosion and fire, Port Wentworth, GA, an investigation report

Jan 2008

CSB. (2008). Imperial Sugar Company dust explosion and fire, Port Wentworth, GA, an investigation report. Washington, DC: U.S. Chemical Safety and Hazard Investigation Board, Source. http://www.csb.gov/investigations/detail.aspx?SID¼6.

West Pharmaceutical Services dust explosion and fire, Kinston, NC, an investigation report

Jan 2003

Hayes Lemmerz dust explosions and fire, Huntington, IN, an investigation report

Jan 2003

CSB. (2003a). West Pharmaceutical Services dust explosion and fire, Kinston, NC, an investigation report. Washington, DC: U.S. Chemical Safety and Hazard Investigation Board, Source. http://www.csb.gov/investigations/detail.aspx?SID¼36. CSB. (2003b). Hayes Lemmerz dust explosions and fire, Huntington, IN, an investigation report. Washington, DC: U.S. Chemical Safety and Hazard Investigation Board, Source. http://www.csb.gov/investigations/detail.aspx?SID¼33.

Experimental determination of dust cloud deflagration parameters of selected hydrogen storage materials: Complex metal hydrides, chemical hydrides, and adsorbents

No full-text available

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