Explosions of vapour/dust hybrid mixtures: A particular class
TL;DR: In this paper, the authors demonstrate the particular aspects of the explosion of hybrid mixtures with respect to either vapour or dust explosions, and demonstrate that the explosion behavior of such hybrid mixture reveals significant differences with respect both vapour and dust explosions; especially a promotion effect on combustion kinetics and on the rate of pressure rise for poor mixtures.
About: This article is published in Powder Technology.The article was published on 2009-03-05. It has received 66 citations till now. The article focuses on the topics: Dust explosion.
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TL;DR: In this article, the explosion features of nicotinic acid dust in atmosphere of methane and air at different concentrations of either dust or gaseous fuel were studied and the authors defined five different regimes of the gas/dust/air mixture explosion in the plane dust concentration vs. fuel concentration.
113 citations
Cites background from "Explosions of vapour/dust hybrid mi..."
...Concerning the explosion severity, the explosion parameters (maximum pressure and deflagration index) have been measured extensively at changing the dust and gas concentrations [11,15–18]....
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...4 214 60 500 2×5 kJ [16]...
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...[15,16] have studied the influence of pharmaceutical dusts and their associated solvent (ethanol, di-isopropyl ether, toluene) concentrations on maximum pressure and maximum rate of pressure rise....
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TL;DR: The necessary conditions for a dust explosion to occur are well-expressed by the explosion pentagon: fuel, oxidant, ignition source, mixing of the fuel and oxidant and confinement of the resulting mixture.
90 citations
TL;DR: In this study, a methodology has been proposed for risk analysis of dust explosion scenarios based on Bayesian network and benefits from a bow-tie diagram to better represent the logical relationships existing among contributing factors and consequences of dust explosions.
Abstract: In this study, a methodology has been proposed for risk analysis of dust explosion scenarios based on Bayesian network. Our methodology also benefits from a bow-tie diagram to better represent the logical relationships existing among contributing factors and consequences of dust explosions. In this study, the risks of dust explosion scenarios are evaluated, taking into account common cause failures and dependencies among root events and possible consequences. Using a diagnostic analysis, dust particle properties, oxygen concentration, and safety training of staff are identified as the most critical root events leading to dust explosions. The probability adaptation concept is also used for sequential updating and thus learning from past dust explosion accidents, which is of great importance in dynamic risk assessment and management. We also apply the proposed methodology to a case study to model dust explosion scenarios, to estimate the envisaged risks, and to identify the vulnerable parts of the system that need additional safety measures.
89 citations
TL;DR: The inhibition mechanism of aluminum dust explosion by ABC powder was summarized systematically based on results and the particles of the explosion residues of Al/NH3 mixture and Al/ABC mixture were significantly larger than those of pure aluminum explosion residues.
87 citations
TL;DR: In this article, a CFD model was developed with the aim at simulating the turbulent flow field induced by dust feeding and dispersion within the 20 L bomb, and the associated effects on the distribution of dust concentration.
Abstract: A CFD model was developed with the aim at simulating the turbulent flow field induced by dust feeding and dispersion within the 20 L bomb, and the associated effects on the distribution of dust concentration. The model was validated considering a set of data (pressure time histories and root mean square velocity) available in the literature. The time sequences of velocity vector and kinetic energy maps have shown that multiple turbulent vortex structures are established within the sphere. These vortices generate dead volumes for the dust which is pushed toward the walls of the sphere. The obtained results are relevant to the practice of dust explosion testing and the interpretation of test results and, then, they should be taken as reference to improve the conditions for standard tests. V C 2013 American Institute of Chemical Engineers AIChE J, 59: 2485–2496, 2013
82 citations
References
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01 Jun 1991
TL;DR: In this article, a comprehensive account of the existing practical and theoretical knowledge of the origin, development, prevention and mitigation of dust explosions in the process industries is presented, along with an up-to-date evaluation of prevalent activities, testing methods, design measures and safe operating techniques.
Abstract: This work is a comprehensive account of the existing practical and theoretical knowledge of the origin, development, prevention and mitigation of dust explosions in the process industries. It offers an up-to-date evaluation of prevalent activities, testing methods, design measures and safe operating techniques in a detailed and comprehensive critique of all the significant phases relating to the hazard and control of a dust explosion. This should be a useful reference work for design, production, maintenance and safety engineers in the process industries, safety consultants and students.
586 citations
TL;DR: In this article, the effects of coal volatility and particle size were evaluated, and the particle size was determined to be at least as important as volatility in determining the explosion hazard for all coals tested, the finest sizes were the most hazardous.
Abstract: This paper reports US Bureau of Mines (USBM) research on the explosibility of coal dusts. The purpose of this work is to improve safety in mining and other industries that process or use coal. Most of the tests were conducted in the USBM 20 litre laboratory explosibility chamber. The laboratory data show relatively good agreement with those from full-scale experimental mine tests. The parameters measured included minimum explosible concentrations, maximum explosion pressures, maximum rates of pressure rise, minimum oxygen concentrations, and amounts of limestone rock dust required to inert the coals. The effects of coal volatility and particle size were evaluated, and particle size was determined to be at least as important as volatility in determining the explosion hazard. For all coals tested, the finest sizes were the most hazardous. The coal dust explosibility data are compared to those of other hydrocarbons, such as polyethylene dust and methane gas, in an attempt to understand better the basics of coal combustion.
210 citations
TL;DR: A comprehensive overview of the available explosion prevention and mitigative systems applicable to gas, dust, mist and hybrid (gas-aerosol) explosions is provided in this article.
68 citations
TL;DR: In this paper, a near-spherical 22.7 L explosibility test chamber, using 2500 J pyrotechnic ignitors, was used to evaluate the explosion behavior of hybrid methane/air/cork dust mixtures.
Abstract: Explosibility studies of hybrid methane/air/cork dust mixtures were carried out in a near-spherical 22.7 L explosibility test chamber, using 2500 J pyrotechnic ignitors. The suspension dust burned as methane/air/dust clouds and the uniformity of the cork dust dispersion inside the chamber was evaluated through optical dust probes and during the explosion the pressure and the temperature evolution inside the reactor were measured. Tested dust particles had mass median diameter of 71.3 mm and the covered dust cloud concentration was up to 550 g/m 3 . Measured explosions parameters included minimum explosion concentration, maximum explosion pressures and maximum rate of pressure rise. The cork dust explosion behavior in hybrid methane/air mixtures was studied for atmospheres with 1.98 and 3.5% (v/v) of methane. The effect of methane content on the explosions characteristic parameters was evaluated. The conclusion is that the risk and explosion danger rises with the increase of methane concentration characterized by the reduction of the minimum dust explosion concentration, as methane content increases in the atmosphere. The maximum explosion pressure is not very much sensitive to the methane content and only for the system with 3.5% (v/v) of methane it was observed an increase of maximum rate of pressure rise, when compared with the value obtained for the air/dust system. q 2005 Elsevier Ltd. All rights reserved.
66 citations
TL;DR: In this paper, the explosion characteristics of coal dust/air and methane/coal dust-air mixtures have been determined experimentally at initial pressures of nominally 1.0 bar in a 26 / spherical explosion bomb.
Abstract: The explosion characteristics of coal dust/air and methane/coal dust/air mixtures have been determined experimentally. All tests were conducted at initial pressures of nominally 1.0 bar in a 26 / spherical explosion bomb. Run-of-mine coal from the Prince, Lingan and Phalen seams of the Cape Breton Development Corporation was used. Two size fractions of each coal were tested at dust concentrations ranging from the lean flammability limit to 1.0 kg m −3 . The explosion parameters measured for each test were the maximum explosion pressure, P max , and the maximum rate of pressure rise, (d P /d t ) max . Methane addition to the coal dust/air mixtures was found to increase both P max and (d P /d t ) max , the effect being most significant at low dust concentrations. A reduction in mass mean diameter of the coal or an increase in the parent coal volatile content was found to have a similar effect on P max and (d P /d t ) max . These observations are consistent with a description of coal dust flame propagation by gas-phase combustion of devolatilization products.
36 citations