The Experts below are selected from a list of 4539 Experts worldwide ranked by ideXlab platform
Jianliang Yu - One of the best experts on this subject based on the ideXlab platform.
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experimental investigation on micro and nano pmma Dust Explosion venting at elevated static activation overpressures
Powder Technology, 2016Co-Authors: Jianliang Yu, Jian Li, Qi Zhang, Xinyan Zhang, Dapeng HuAbstract:The coupling relationships between vented pressures and flames of micro- and nano-PMMA particles at elevated static activation overpressures were examined using the standard 20-L spherical Dust Explosion venting apparatus to reveal the differences of venting processes at different particle scales. It was found that by increasing the venting diameter or decreasing the static activation pressure, the maximum reduced overpressure of micro-PMMA particles was reduced significantly compared with that of nano-PMMA particles. By increasing the venting diameter, the competition between the pressure venting and flame venting was gradually transformed. For 100-nm PMMA particles, the vented flame would experience the advanced under-expanded jet flame, moderate under-expanded jet flame, subsonic jet flame and constant pressure combustion, with the latter two modes appearing only with a larger venting diameter. However, the venting process of 30-μm PMMA particles only underwent the moderate under-expanded jet flame, constant pressure combustion appearing only with a larger venting diameter. The flame venting accomplished later or earlier than the pressure venting depended on the venting diameter significantly. The vented flame scale and radiation intensity of the 100-nm PMMA particles were much stronger at the same concentration.
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motion behaviors of the unburned particles ahead of flame front in hexadecanol Dust Explosion
Powder Technology, 2015Co-Authors: Toshio Mogi, Jianliang Yu, Jianzhong Rong, Ritsu DobashiAbstract:Abstract To reveal clearly the motion behaviors and velocity distributions of the unburned particles ahead of flame front in hexadecanol Dust Explosion, the flame propagation process was recorded by a high speed camera combining the particle image velocimetry (PIV) techniques. Flame region was recognized from the direct-light-emission photographs by the color model; Otsu's automatic threshold segmentation model and Fast Fourier Transform were adopted to set the threshold and to measure the flow field, respectively. It was observed that the propagating flame consisted of blue-spots of flame at the leading zone and luminous flame behind them. The flame firstly propagated towards the small particles nearby, when the small particles were completely pyrolyzed, the local pre-mixing flame would continue to heat the larger particles, establishing the local diffusion flame, and then the isolated blue luminous spots. Single Dust particle velocity changed with the distance to the flame front. There existed a stagnation region, in which the particle velocities approached zero. Beyond this region, the particles settled down at a constant velocity. Vortex structures appeared in the regions where the settlement particles encountered with the outward movement particles.
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Dust Explosion venting of small vessels at the elevated static activation overpressure
Powder Technology, 2014Co-Authors: Jianliang YuAbstract:Abstract Four venting diameters were chosen to carry out the simple venting experiments of 70 μm lycopodium Dust Explosions in a 20-L chamber at the elevated static activation overpressures ranging from 1.2 bar to 6 bar to evaluate the vent sizing correlations proposed by NFPA 68:2007 and EN 14491:2006. Before conducting Dust Explosion venting experiments, the static activation overpressures of the membranes at different vent diameters and different membrane layers were firstly determined. The linear relationship was quantified versus membrane layer at four venting diameters. The experimental results in a confined 20-L chamber represent that the maximum overpressure is 6.5 bar at 750 g·m− 3 and the maximum rate of pressure rise is 283.0 bar·m·s− 1 at about 1000 g·m− 3 for 70 μm lycopodium Dust. The comparison of simple venting results and the calculated results according to NFPA 68 and EN 14491 at the elevated static activation overpressures shows that NFPA 68 results have a good predictive ability in a certain range of vent diameters. The predictive results tend to be conservative for small vent diameters and dangerous for large ones. EN 14491 results are too conservative and unreliable. The reasons of vent sizing divergence between the NFPA 68 results and EN 14491 results at the elevated static activation overpressures were analyzed according to the empirical functions.
Paul Amyotte - One of the best experts on this subject based on the ideXlab platform.
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risk analysis of Dust Explosion scenarios using bayesian networks
Risk Analysis, 2015Co-Authors: Zhi Yuan, Faisal Khan, Nima Khakzad, Paul AmyotteAbstract: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.
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Development of an organizational framework for studying Dust Explosion phenomena
Journal of Loss Prevention in The Process Industries, 2014Co-Authors: Chris T. Cloney, Paul Amyotte, Faisal Khan, Robert C. RipleyAbstract:To develop a predictive Dust Explosion model or theory many considerations of the interaction between several complex multiscale processes are required. Due to practical considerations only some of the processes may be fully resolved, while the rest must be approximated or neglected. The current study focuses on constructing an organizational framework for Dust Explosion model development. The framework is organized based on progression of the Explosion in time and geometric scale of the important features. Suggested methodologies are given to investigate the small-scale features and develop feed-forward approximations for predictive models at the larger system-scale. The concepts developed through constructing the organizational framework are applied to closed volume Dust Explosion testing and classification of several sources of experimental variance for this system is given.
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a model to assess Dust Explosion occurrence probability
Journal of Hazardous Materials, 2014Co-Authors: Junaid Hassan, Paul Amyotte, Faisal Khan, Refaul FerdousAbstract:Dust handling poses a potential Explosion hazard in many inDustrial facilities. The consequences of a Dust Explosion are often severe and similar to a gas Explosion; however, its occurrence is conditional to the presence of five elements: combustible Dust, ignition source, oxidant, mixing and confinement. Dust Explosion researchers have conducted experiments to study the characteristics of these elements and generate data on explosibility. These experiments are often costly but the generated data has a significant scope in estimating the probability of a Dust Explosion occurrence. This paper attempts to use existing information (experimental data) to develop a predictive model to assess the probability of a Dust Explosion occurrence in a given environment. The pro-posed model considers six key parameters of a Dust Explosion: Dust particle diameter (PD), minimum ignition energy (MIE), minimum explosible concentration (MEC), minimum ignition temperature (MIT), limiting oxygen concentration (LOC) and Explosion pressure (Pmax). A conditional probabilistic approach has been developed and embedded in the proposed model to generate a nomograph for assessing Dust Explosion occurrence. The generated nomograph provides a quick assessment technique to map the occurrence probability of a Dust Explosion for a given environment defined with the six parameters.
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InDustry specific Dust Explosion likelihood assessment model with case studies
Journal of Chemical Health and Safety, 2014Co-Authors: Junaid Hassan, Paul Amyotte, Faisal Khan, Refaul FerdousAbstract:Dust Explosion is a potential threat to the process facilities handling Dusts. Dust Explosion occurrences are frequently reported in these inDustries. InDustrial professionals and researchers have been trying to develop effective measures to assess and mitigate and/or prevent Dust Explosion. To develop effective prevention and mitigation strategies, it is important to understand the interaction of Dust Explosion controlling parameters and also to assess likelihood of occurrence in given conditions. Authors have proposed a conceptual framework to model Dust Explosion likelihood. In this paper, a detailed implementation of the conceptual model is presented. Three different Dust classes (i.e. food feed; plastic, resin and rubber; and metal alloys) are considered for model development. The proposed model considers six key parameters of Dust Explosion: Dust particles diameter, minimum ignition energy, minimum explosible concentration, minimum ignition temperature, limiting oxygen concentration and Explosion pressure. These parameters are conditional to the type of Dust and chemical composition. A conditional probabilistic approach is used to determine the total probability of Dust Explosion in a given process facility. Use of this model will help to assess the likelihood of Dust Explosion in given operating conditions. Moreover, it will help to develop prevention strategies focusing on the parameters that are responsible for Dust Explosion. Three case studies are presented here to demonstrate the application of the model in real life.
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risk based design of safety measures to prevent and mitigate Dust Explosion hazards
Industrial & Engineering Chemistry Research, 2013Co-Authors: Zhi Yuan, Paul Amyotte, Faisal Khan, Nima Khakzad, Genserik ReniersAbstract:Dust Explosion is one of the main threats to equipment safety and human health in inDustries. Complex factors leading to accidents, serious consequences, and relevant safety measures are the main interests of governmental agencies, researchers, and inDustrial companies. However, a generic risk analysis model for Dust Explosions is absent. The bow-tie model can be used to investigate the relationships among basic causes, safety barriers, and possible consequences of an accident scenario. In this paper, a framework is established for quantitative risk assessment of Dust Explosions based on bow-tie analysis via review and analysis of previous major Dust Explosions. A large inventory of relevant safety measures is presented, and the implementation and efficacy of such safety measures to reduce the risk of Dust Explosions is thoroughly discussed. Finally, the methodology is applied to a case study. The results show that the generic bow-tie developed in this study can be tailored to a wide variety of Dust explo...
Faisal Khan - One of the best experts on this subject based on the ideXlab platform.
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risk analysis of Dust Explosion scenarios using bayesian networks
Risk Analysis, 2015Co-Authors: Zhi Yuan, Faisal Khan, Nima Khakzad, Paul AmyotteAbstract: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.
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Development of an organizational framework for studying Dust Explosion phenomena
Journal of Loss Prevention in The Process Industries, 2014Co-Authors: Chris T. Cloney, Paul Amyotte, Faisal Khan, Robert C. RipleyAbstract:To develop a predictive Dust Explosion model or theory many considerations of the interaction between several complex multiscale processes are required. Due to practical considerations only some of the processes may be fully resolved, while the rest must be approximated or neglected. The current study focuses on constructing an organizational framework for Dust Explosion model development. The framework is organized based on progression of the Explosion in time and geometric scale of the important features. Suggested methodologies are given to investigate the small-scale features and develop feed-forward approximations for predictive models at the larger system-scale. The concepts developed through constructing the organizational framework are applied to closed volume Dust Explosion testing and classification of several sources of experimental variance for this system is given.
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a model to assess Dust Explosion occurrence probability
Journal of Hazardous Materials, 2014Co-Authors: Junaid Hassan, Paul Amyotte, Faisal Khan, Refaul FerdousAbstract:Dust handling poses a potential Explosion hazard in many inDustrial facilities. The consequences of a Dust Explosion are often severe and similar to a gas Explosion; however, its occurrence is conditional to the presence of five elements: combustible Dust, ignition source, oxidant, mixing and confinement. Dust Explosion researchers have conducted experiments to study the characteristics of these elements and generate data on explosibility. These experiments are often costly but the generated data has a significant scope in estimating the probability of a Dust Explosion occurrence. This paper attempts to use existing information (experimental data) to develop a predictive model to assess the probability of a Dust Explosion occurrence in a given environment. The pro-posed model considers six key parameters of a Dust Explosion: Dust particle diameter (PD), minimum ignition energy (MIE), minimum explosible concentration (MEC), minimum ignition temperature (MIT), limiting oxygen concentration (LOC) and Explosion pressure (Pmax). A conditional probabilistic approach has been developed and embedded in the proposed model to generate a nomograph for assessing Dust Explosion occurrence. The generated nomograph provides a quick assessment technique to map the occurrence probability of a Dust Explosion for a given environment defined with the six parameters.
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InDustry specific Dust Explosion likelihood assessment model with case studies
Journal of Chemical Health and Safety, 2014Co-Authors: Junaid Hassan, Paul Amyotte, Faisal Khan, Refaul FerdousAbstract:Dust Explosion is a potential threat to the process facilities handling Dusts. Dust Explosion occurrences are frequently reported in these inDustries. InDustrial professionals and researchers have been trying to develop effective measures to assess and mitigate and/or prevent Dust Explosion. To develop effective prevention and mitigation strategies, it is important to understand the interaction of Dust Explosion controlling parameters and also to assess likelihood of occurrence in given conditions. Authors have proposed a conceptual framework to model Dust Explosion likelihood. In this paper, a detailed implementation of the conceptual model is presented. Three different Dust classes (i.e. food feed; plastic, resin and rubber; and metal alloys) are considered for model development. The proposed model considers six key parameters of Dust Explosion: Dust particles diameter, minimum ignition energy, minimum explosible concentration, minimum ignition temperature, limiting oxygen concentration and Explosion pressure. These parameters are conditional to the type of Dust and chemical composition. A conditional probabilistic approach is used to determine the total probability of Dust Explosion in a given process facility. Use of this model will help to assess the likelihood of Dust Explosion in given operating conditions. Moreover, it will help to develop prevention strategies focusing on the parameters that are responsible for Dust Explosion. Three case studies are presented here to demonstrate the application of the model in real life.
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risk based design of safety measures to prevent and mitigate Dust Explosion hazards
Industrial & Engineering Chemistry Research, 2013Co-Authors: Zhi Yuan, Paul Amyotte, Faisal Khan, Nima Khakzad, Genserik ReniersAbstract:Dust Explosion is one of the main threats to equipment safety and human health in inDustries. Complex factors leading to accidents, serious consequences, and relevant safety measures are the main interests of governmental agencies, researchers, and inDustrial companies. However, a generic risk analysis model for Dust Explosions is absent. The bow-tie model can be used to investigate the relationships among basic causes, safety barriers, and possible consequences of an accident scenario. In this paper, a framework is established for quantitative risk assessment of Dust Explosions based on bow-tie analysis via review and analysis of previous major Dust Explosions. A large inventory of relevant safety measures is presented, and the implementation and efficacy of such safety measures to reduce the risk of Dust Explosions is thoroughly discussed. Finally, the methodology is applied to a case study. The results show that the generic bow-tie developed in this study can be tailored to a wide variety of Dust explo...
Kwanhua Hu - One of the best experts on this subject based on the ideXlab platform.
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investigation of the decomposition reaction and Dust Explosion characteristics of crystalline dicumyl peroxide
Process Safety and Environmental Protection, 2010Co-Authors: Kaitai Lu, Tingchi Chen, Kwanhua HuAbstract:The dicumyl peroxide (DCP) is widely used as a polymerization initiator, catalyst and vulcanizing agent in the chemical inDustry. A number of accidents have been caused by its thermal instability in storage or manufacturing process. Thus, its hazard characteristics have to be clearly identified. First of all, the differential scanning calorimeter (DSC) is used to measure the heat of decomposition reaction, which can contribute to understanding the reaction characteristics of DCP. The accelerating rate calorimeter (ARC) is used to measure the rates of temperature and pressure rises of decomposition reaction, and then the kinetics parameters are estimated. Furthermore, the MIKE 3 apparatus and the 20-l-Apparatus are used to measure and analyze the Dust Explosion characteristics of DCP at room temperature and atmospheric pressure. Finally, Semenov's thermal Explosion theory is applied to investigate the critical runaway condition and the stability criterion of decomposition reaction, and to build the relationship of critical temperature, convective heat transfer coefficient, heat transfer surface area and ambient temperature. These results contribute to improving the safety in the reaction, transportation and storage processes of DCP.
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investigation of the decomposition reaction and Dust Explosion characteristics of crystalline benzoyl peroxides
Journal of Hazardous Materials, 2009Co-Authors: Kaitai Lu, Tingchi Chen, Kwanhua HuAbstract:The benzoyl peroxide (BPO) is widely used in the chemical inDustry. Many catastrophes have been caused by its thermal instability or reactive incompatibility in storage or thermal decomposition reaction. Thus, its hazard characteristics have to be clearly identified. First of all, the differential scanning calorimeter (DSC) is used to measure the heat of decomposition reaction, which can contribute to understanding the reaction characteristics of benzoyl peroxide. The accelerating rate calorimeter (ARC) is used to measure the rates of temperature and pressure rises of decomposition reaction, and then the kinetics parameters are estimated. Furthermore, the MIKE 3 apparatus and the 20-l-Apparatus are used to measure and analyze the Dust Explosion characteristics of benzoyl peroxide under room temperature and atmospheric pressure. Finally, Semenov's thermal Explosion theory is applied to investigate the critical runaway condition and the stability criterion of decomposition reaction, and to build the relationship of critical temperature, convective heat transfer coefficient, heat transfer surface area and ambient temperature. These results contribute to improving the safety in the reaction, transportation and storage processes of benzoyl peroxide.
P Holbrow - One of the best experts on this subject based on the ideXlab platform.
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Dust Explosion venting of small vessels and flameless venting
Process Safety and Environmental Protection, 2013Co-Authors: P HolbrowAbstract:Abstract Dust Explosion venting is an established method of protecting against damaging Explosion over-pressures, and guidance is available for many inDustrial situations. However, there is a need to: (a) establish the venting requirements of small vessels and whether current guidance and predictions in BS EN 14491:2006 need revising, and (b) improve understanding of the potential and limitations of flameless venting. This paper describes initial results from an ongoing programme of research. Small vessel tests are carried out using cornflour and wood Dust on: a commercial sieve unit, a commercial cyclone, and a 0.5 m3 test vessel with Explosion-relief openings without vent covers. Initial 0.5 m3 vessel tests give reduced Explosion pressures that are lower than those predicted. This is because the predicted pressures are based on openings with vent covers. The reduced Explosion pressures measured in the sieve unit and the cyclone are also less than predicted: the reasons are discussed. Flameless vesting tests are carried out using cornflour and wheat flour on a commercial flame arrestor unit. Initial tests demonstrate benefits, particularly a high level of flame extinguishment, but a problem of reduced venting efficiency compared to conventional venting. These initial results indicate that further research is needed.
