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Determining the laminar flame speed of dusts is far from straightforward. A strong dependency on the experimental setup and the data treatment's high complexity makes it a true challenge. This work compares three complementary experimental setups to measure the laminar flame speed of organic dust (here, cellulose): a modified Hartmann tube, a 20 L sphere, and a micro‐fluidized bed (MFB) burner. The first two consider the flame propagation phenomenon in its globality, which means that numerous steps are involved simultaneously (particle heating, pyrolysis, oxidation, radiative transfer, flame stretching), while the third one decouples pyrolysis and combustion, to focus mainly on the oxidation rate. An MFB was conceived to generate pyrolysis products and burn them in a laminar flame. Unstretched flame velocities determined with the first two setups were consistent and equal to 22.0 and 26.6 cm ∙ s−1, respectively. Using Silvestrini's equation, values ranging between 14.0 and 33.4 cm ∙ s−1 were obtained according to the dust concentration. With the MFB burner, the flame speed was much higher (135–155 cm ∙ s−1), due to the higher temperature of the fresh mixture and the fact that only the oxidation of the pyrolysis gases is considered. A numerical simulation (Chemkin) confirmed these results since the range 135 to 231 cm ∙ s−1 was obtained for equivalence ratios of 0.6 and 1.2, respectively. The discrepancy between the laminar flame speed determined in the sphere or in the tube and that obtained in the MFB highlights the significant influence of particle heating and pyrolysis during a dust explosion. [ABSTRACT FROM AUTHOR]

In this article, dust explosion phenomena and the status of research conducted on silos are reviewed. Dust explosions cause loss of life and property in many industrial facilities. There are many recorded dust explosion cases in our country as well as in the world. For example, in our country, in 2023, a dust explosion occurred in the TMO Kocaeli General Directorate (Derince Port Silo), in which 2 people died and great material damage occurred, as reflected in the national press. When we look at the various dust explosion cases that have occurred in the world, it is understood that they mostly occur in silos used for storage in the agricultural and food sectors. Licensed warehouses have been established in many regions of our country in order to store basic and processed agricultural products that can be standardized with the Agricultural Products Licensed Warehousing Law No. 5300, which came into force after being published in the Official Gazette on 17/02/2005, in safe and healthy conditions in warehouses belonging to licensed warehouse enterprise and continues to be established. It is important to understand the many factors affecting dust explosion, such as dust dispersion, properties, discharge, etc., and to design silos according to these factors. These effects are tried to be determined and understood through experimental or CFD simulations. [ABSTRACT FROM AUTHOR]

In the study, the secondary explosion characteristics of TiH 2 dust with different particle sizes induced by hydrogen-oxygen detonations were studied, using a shock tube with semi-open and seal conditions. The processes of dispersal and deflagration were analyzed by a high-speed camera, and the explosion temperature and pressure were measured with the two-color pyrometer technique and pressure sensors, respectively. The experiment results showed that the dust clouds of TiH 2 with smaller particle sizes were larger in volumes and more liable to combust. With the decrease of particle size, the deflagration processes of TiH 2 dust became more intense, while their average temperatures had reverse trends, that is, lager particle sizes had higher average deflagration temperatures. Compared with the semi-open condition of shock tube, the duration of combustion under the confined condition was prolonged and the shock waves were enhanced for the wall reflection, which made the ignition of TiH 2 dust more possible and the subsequent deflagration more violent. Furthermore, the effects of semi-open and seal conditions of shock tube on the peak pressures of secondary explosion were different, compared with no TiH 2 dust addition, the peak pressures of secondary explosion with TiH 2 powders decreased in semi-open condition but increased in seal condition. [Display omitted] • Secondary explosion of TiH 2 dust induced by hydrogen detonation were simulated. • Dust lifting characteristics of TiH 2 under the high-speed airflow were studied. • Dynamic flame temperature distributions of TiH 2 dust explosion were mapped. • Gas-solid two-phase interaction effects during TiH 2 dust explosion were analyzed. [ABSTRACT FROM AUTHOR]

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This research was aimed at comparing the fire characteristics of different types of pepper in the context of explosion prevention. The following characteristics were studied: explosion pressure Pmax and Kst at selected concentrations, ignition temperature of the deposited dust layer from the hot surface, and minimum ignition energy. The comparison of the chemical properties of the used types of pepper was performed using TG/DSC. The results of the measurements suggest that different types of peppers exhibit different explosion characteristics. Each sample reached the maximum value of the explosion pressure and rate of pressure rise at different concentrations. The volume of the explosion chamber used also influenced the explosion characteristics. It is a consequence of the fact that the explosion characteristics strongly depend on the mechanism of action of a particular igniter. The minimum effect on the safety characteristics was observed when measuring the minimum ignition energy and the minimum ignition temperature of the dust layer from the hot surface. The results of the measurements suggest that different types of peppers exhibit different explosion characteristics. This information should then be considered in explosion prevention. [ABSTRACT FROM AUTHOR]

Given the prevalence of Al/RDX energetic dust in industrial production, this study investigates their ignition safety and explosion hazards using Hartmann tubes and 20 L spherical explosion containers. The minimum ignition energy (MIE) increases from 20 mJ to 55 mJ as RDX content increases, indicating that adding RDX enlarges the effective particle size of the dust, thereby reducing its ignition sensitivity. A logistic regression model was used to develop a fitting equation for ignition probability, correlating dust concentration and ignition energy. The flame propagation velocity and explosion pressure of the energetic dust initially increase and then decrease with increasing RDX content. Optimal combustion characteristics were observed at 20 % RDX, with the maximum flame propagation velocity of 101 m s−1. However, the peak flame temperature decreases with increasing RDX content. The maximum explosion pressure and maximum explosion index at 1.77 MPa and 186.99 MPa m s−1 respectively, at 40 % RDX content. These findings highlight that 20 % RDX content yields the best combustion characteristics, while 40 % RDX content offers the maximum explosive potential, providing valuable insights for enhancing safety measures in industrial applications involving energetic dusts.

The flame propagation processes of MgH2 dust clouds with four different particle sizes were recorded by a high-speed camera. The dynamic flame temperature distributions of MgH2 dust clouds were reconstructed by the two-color pyrometer technique, and the chemical composition of solid combustion residues were analyzed. The experimental results showed that the average flame propagation velocities of 23 μm, 40 μm, 60 μm and 103 μm MgH2 dust clouds in the stable propagation stage were 3.7 m/s, 2.8 m/s, 2.1 m/s and 0.9 m/s, respectively. The dust clouds with smaller particle sizes had faster flame propagation velocity and stronger oscillation intensity, and their flame temperature distributions were more even and the temperature gradients were smaller. The flame structures of MgH2 dust clouds were significantly affected by the particle sinking velocity, and the combustion processes were accompanied by micro-explosion of particles. The falling velocities of 23 μm and 40 μm MgH2 particles were 2.24 cm/s and 6.71 cm/s, respectively. While the falling velocities of 60 μm and 103 μm MgH2 particles were as high as 15.07 cm/s and 44.42 cm/s, respectively, leading to a more rapid downward development and irregular shape of the flame. Furthermore, the dehydrogenation reaction had a significant effect on the combustion performance of MgH2 dust. The combustion of H2 enhanced the ignition and combustion characteristics of MgH2 dust, resulting in a much higher explosion power than the pure Mg dust. The micro-structure characteristics and combustion residues composition analysis of MgH2 dust indicated that the combustion control mechanism of MgH2 dust flame was mainly the heterogeneous reaction, which was affected by the dehydrogenation reaction.

A numerical model for the calculation of the minimum ignition energy (MIE) of dust clouds is developed based on heat transfer and particle reaction kinetics. The model is an update of previous models relying on the experimental minimum ignition temperature (MIT) of dust clouds. Gas and particle temperature profiles during the spark ignition processes are studied in detail to generate dust cloud MIE prediction. For the 20 dusts studied, with the updated model, the average calculated MIE over experimental MIE ratio is 81.6%, a significant improvement compared with the ratio of 48.1% using a previous model with the MIT. A strong correlation is found between the dust cloud MIE and the MIE of the nearest particle to the spark center in the dust cloud: for all the studied dusts, the latter accounts for over 85% of the dust cloud MIE. Moreover, the minimum spark ignition temperature of a dust particle (SITP) can be defined, which also strongly correlates with the dust particle MIT (MITP) calculated using the Semenov theory. Based on these correlations, simple MIE predictive equations are derived and validated by comparing their MIE predictions with the experimental MIE data. [ABSTRACT FROM AUTHOR]

Aluminum hydride (AlH 3) dust is a high-capacity hydrogen storage material but is prone to explosion. In this paper, explosion characteristics and flame propagation behavior of AlH 3 dust are investigated. The results indicate that the exposure of bare aluminum and the increase of specific surface area lead to the maximum explosion pressure of AlH 3 dust being 4 times higher than that of Al dust. The enhancement of heat transfer by hydrogen combustion causes a higher combustion rate, leading to a higher maximum explosion pressure rise rate and flame propagation velocity of AlH 3 dust. The thermo-diffusive instabilities and the evolution of hydrogen result in a pulsation flame propagation velocity of AlH 3 dust. Combining the explosion temperature calculated by NASA CEA with the explosion residues analysis, the explosion mechanism of AlH 3 dust is further revealed. The break of the oxide film and the combustion of hydrogen result in a different explosion mechanism. • The explosion characteristics and flame propagation behavior of AlH 3 dust are investigated. • The hydrogen evolution characteristic is studied by the comparison of Al dust. • The explosion mechanism of AlH 3 dust is revealed. [ABSTRACT FROM AUTHOR]

The relevant standards at home and abroad offer the calculation method for explosion venting area（EVA） of individual equipment, but there is a notable absence of guidelines for interconnected equipment. By means of FLACS numerical simulation, taking corn starch as the explosion medium, the reduced explosion pressure（REP） and rate of pressure rise in the connected equipment are simulated and explored. The results show that when the length of the pipe is fixed, the maximum REP in the booster vessel decreases with the increasement of the EVA. When the same EVA is set, the maximum REP in the booster vessel increases with the increase of the pipe length, and the time to reach the maximum REP value also delays. The minimum safe EVA required for the booster vessel is larger than that of the single equipment with same size, indicating that the calculation formula of the EVA of the single equipment is unreliable for the connected equipment. Through numerical fitting, the EVA calculation formula for single equipment in the standard was modified to meet the requirement of connected equipment. The research results provide reference for explosion-proof design for connected system. [ABSTRACT FROM AUTHOR]

This paper discusses the effects of gravity on the combustion-wave propagation through a dust cloud. Two models, continuum and point-source models, are developed by extending the models of Goroshin et al. to consider gravity effects. The continuum model treats a particle cloud as a continuum phase, while the point-source model considers heat generation from individual particles; hence, the latter model better represents the actual phenomenon. Both the models have three dimensionless parameters: dimensionless reaction time, τc, dimensionless ignition temperature, θign, and dimensionless terminal velocity of particles, Ug. It is first confirmed that the continuum model is a good approximation of the point-source model when τc ≳ 1, whereas their differences are apparent when τc ≲ 1. Evaluating the values of τc for the propagation through a cloud of aluminum particles shows that τc is less than unity in conditions of interest. The point-source model is therefore applied to assessing the gravity effect, revealing that the extinction condition (minimum explosive concentration, MEC) is significantly influenced by gravity even for particles as small as 10 μm. [ABSTRACT FROM AUTHOR]

This research was aimed at comparing the fire characteristics of different types of pepper in the context of explosion prevention. The following characteristics were studied: explosion pressure Pmax and Kst at selected concentrations, ignition temperature of the deposited dust layer from the hot surface, and minimum ignition energy. The comparison of the chemical properties of the used types of pepper was performed using TG/DSC. The results of the measurements suggest that different types of peppers exhibit different explosion characteristics. Each sample reached the maximum value of the explosion pressure and rate of pressure rise at different concentrations. The volume of the explosion chamber used also influenced the explosion characteristics. It is a consequence of the fact that the explosion characteristics strongly depend on the mechanism of action of a particular igniter. The minimum effect on the safety characteristics was observed when measuring the minimum ignition energy and the minimum ignition temperature of the dust layer from the hot surface. The results of the measurements suggest that different types of peppers exhibit different explosion characteristics. This information should then be considered in explosion prevention.

Polymers and their processing by engineering production technologies (injection, molding or additive manufacturing) are increasingly being used. Polymers used in engineering production technologies are constantly being developed and their properties are being improved. Granulometry, X-ray, FTIR and TGA were used to characterize polymer samples. Determination of the fire parameters of powder samples of polyamide (PA) 12, polypropylene, and ultra-high molecular weight (UHMW) polyethylene is the subject of the current article. An explosive atmosphere can be created by the powder form of these polymer materials, and introduction of preventive safeguards to ensure safety is required for their use. Although the fire parameters of these basic types of polymers are available in databases (e.g., GESTIS-DustEx), our results showed that one of the samples used (polypropylene) was not flammable and thus is safe for use in terms of explosiveness. Two samples were flammable and explosive. The lower explosive limit was 30 g·m−3 (PA12) and 60 g·m−3 (UHMW polyethylene). The maximum explosion pressure of the samples was 6.47 (UHMW polyethylene) and 6.76 bar (PA12). The explosion constant, Kst, of the samples was 116.6 bar·m·s−1 (PA12) and 97.1 bar·m·s−1 (UHMW polyethylene). Therefore, when using polymers in production technologies, it is necessary to know their fire parameters, and to design effective explosion prevention (e.g., ventilation, explosive-proof material, etc.) measures for flammable and explosive polymers. [ABSTRACT FROM AUTHOR]

大豆压榨厂的粉尘主要是有机粉尘,又分为大豆粉尘、含溶剂粉尘、豆粕粉尘，在生产中产生粉尘层和粉尘云，可能引发爆炸。在阐述粉尘及粉尘爆炸相关概念基础上，指出大豆压榨厂积尘区域及潜在火源，并提出相关处理措施，包括划分可燃性粉尘爆炸风控区，设置关键安全装置和运行监控装置，制订火源预防措施和设备粉尘控制措施，防止粉尘层阴燃和粉尘云爆炸，按相关标准设计防火防爆厂房结构，大豆预处理车间设计并使用安全风网等。通过相关处理措施以最大限度地降低大豆压榨厂粉尘爆炸隐患，做到安全生产，保护员工和公司的财产。 The dusts in the soybean crushing plant are mainly organic dust, and the dusts are also divided into the soybean dust and containing hexane dust and the soybean meal dust. The dust layer and the dust cloud are produced in the production, which may cause explosion. Based on the elaboration of dust and dust explosion related concepts, the dust accumulation areas and potential sources of fire in soybean crushing plants were pointed out, and relevant treatment measures were proposed, including the dividing combustible dust explosion control areas, setting up critical safety devices and running monitoring devices, developing fire prevention measures and equipment dust control measures, preventing dust layer from smoldering and dust cloud explosion, designing fire and explosion-proof plant structures according to relevant standards, and designing and using safety ventilation network in soybean pretreatment workshop, etc. Through relevant measures to minimize the hidden danger of dust explosion in soybean crushing plant, to achieve safe production and protect the property of employees and the company.

The suppression effects of melamine polyphosphate, titanium dioxide and melamine cyanurate powders on titanium hydride dust explosions were studied using a 1.2 L standard Hartmann tube system, a 20-L spherical vessel testing system, a simultaneous thermal analyzer and a field emission scanning electron microscope. The experimental results showed that the three solid suppressants could effectively decrease the explosion parameters such as flame luminescence intensity, flame propagation velocity and maximum explosion pressure, et al. Because of the different suppression characteristics of the suppressants, their suppression effects on the particles combustion temperatures were significantly different. To completely suppress the dust explosion of titanium hydride, the inerting ratio of the melamine polyphosphate powders was the smallest when compared with those of the titanium dioxide and melamine cyanurate powders. In addition, the field emission scanning electron microscope was used to analyze the residues of a dust explosion. The testing results showed that the thermal decomposition residues of melamine polyphosphate powders were coating on the surface of the unburned titanium hydride particles to make them lose reactivity, that was why the suppression effect of melamine polyphosphate powders was the most effective when compared with titanium dioxide and melamine cyanurate powders. [Display omitted] [ABSTRACT FROM AUTHOR]

The floating dust at different heights in the warehouse where the fermented waste mash is stacked is selected, and the three kinds of dust in the upper, middle, and lower layers are named floating dust U (Upper), floating dust M (Middle) and floating dust L(Lower) respectively. The physical characteristics of three kinds of floating dust were studied to analyze the change in dust explosion characteristics. It was found that the maximum explosion pressure Pmax increased with the increase of volatile content and the decrease of ash content. In addition, the change rules of explosion overpressure, minimum ignition energy, lower explosion limit, and flame propagation velocity of floating dust M in 1%, 2%, and 3% alcoholic atmosphere were investigated. It was found that alcohol acted as a volatile component in this mixed explosion system, which not only enhanced the explosion intensity but also enhanced the explosion sensitivity. Finally, with the change of explosion constant, it is pointed out that the dust explosion hazard level changes from St1 to St2 due to the presence of the alcoholic atmosphere. [ABSTRACT FROM AUTHOR]

A simulation investigation on the flow domain and particle movement pattern in the dispersion stage of dust explosion experiment were conducted using CFD simulation based on Euler–Lagrange approach. A new solver that couples two phases was developed based on the default solver rhoPimpleFoam from the OpenFOAM tool kit. Three sizes of particles 25 μm, 125 μm and 250 μm were simulated and studied. The simulation results of dust front propagation were evaluated by the experiment data. Particles with smaller diameters tended to move slower. Due to the high turbulence, flow vortices in the lower part of the dispersion domain were identified. These vortices gradually became larger with time and the decrease of inflow velocity. Uneven distribution of particles along with the equipment and high concentration of particles between the discharge electrodes were found in the simulation. Furthermore, particles with higher velocity favored the middle position in the tube. These facts suggested that the ignition delay time for particles larger than 125 μm should be higher than 60 ms.

Dust explosions are a major concern in many industrial facilities and particularly in storage areas of biomass materials. Although venting standards (EN 14491 and NFPA 68) provide satisfactory safety levels for most industrial applications, they present some limitations and there exist situations that they do not contemplate. Vented dust explosions in a 4500 m3 silo for the storage of wood pellets were simulated by computational fluid dynamics. Maximum overpressures were registered and compared. The influence of several parameters including initial turbulence level, dust concentration, ignition location, and vent area was studied. A factorial analysis was carried out to determine the importance of each of the four parameters, along with possible interactions between them. The results showed great variations in the overpressures between the different scenarios simulated. Vent area, ignition location, and dust concentration showed similar effects on the overpressure (around 25%), while initial turbulence had half this effect (13%). One interaction effect out of the eleven possible interactions was identified as relevant for this specific industrial scenario: the combination of the ignition location and the initial turbulence, with an additional effect of 5% on the overpressure. The factorial analysis applied in this study could be of interest to the risk assessment of industrial facilities. [ABSTRACT FROM AUTHOR]

The explosion process and chemical activity of pyrite dust were investigated by explosion test, thermo-gravimetric analysis and FactSage numerical simulation. Based on the results of tests and simulation of pyrite dust explosion, a numerical model was developed to reveal the explosion process. The results indicate that the explosion process is controlled by heterogeneous combustion and the volatilization of sulfur oxides leads to weight loss of pyrite dust. In addition, the explosion severity is dominated by the sulfur content, and the apparent activity energy of pyrite dust decreases with the sulfur content increasing, resulting in enhancing chemical activity and weight loss. Compared to pyrrhotite dust explosion, pyrite is less susceptible to oxidation, but pyrite dust is more explosive. [ABSTRACT FROM AUTHOR]

Theoretical predictions of dust-explosion characteristics, such as the minimum explosive concentration (MEC), can help improve the accuracy of quantitative risk assessment. This paper presents a continuum model to simulate one-dimensional dust-cloud combustion. It is found that the dilution of dust by thermal expansion reduces the propagation speed of a combustion wave through a dust cloud. At the same time, the delay in the increase of particle velocity due to relaxation time counteracts the dilution effect. Therefore, neglecting the relaxation time results in the underestimation of propagation speed. In the absence of heat loss, extinction occurs when the adiabatic combustion temperature decreases to the ignition temperature; MEC is independent of particle size in such cases. With the presence of heat loss, on the other hand, extinction occurs at a higher dust concentration; MEC increases with particle size. Accurate evaluation of ignition temperature is key to the quantitative prediction of MEC. A particular focus is given to gravity effects, reflecting recent experimental efforts to obtain fundamental insights into propagation mechanisms without being affected by gravity. In upward propagation, particles fall toward the reaction front, enhancing combustion and increasing the propagation speed. The situation in downward propagation is the opposite, and extinction occurs when the gravity level is beyond a critical value. In upward propagation, MEC can decrease with an increase in particle size, owing to the influence of gravity. [ABSTRACT FROM AUTHOR]

Investigations into the deactivation of explosion sensitivity and reduction of flame propagation for aluminium alloy polishing wastes were carried out by the addition of ultrafine Al(OH)3 inerting agent. Meanwhile, high-purity aluminium powders with similar mean diameters were also used as a comparative study. The explosion propagation characteristics of high-purity aluminium dust and aluminium alloy polishing waste dust under different inerting ratios (ε) were tested and investigated using a standardised Hartmann tester and a developed experimental platform. The results show that the minimum ignition energy of high-purity aluminium powder is between 40 and 45 mJ, and the minimum ignition energy of aluminium alloy polishing waste is between 500 and 550 mJ, which is one order of magnitude higher than that of high-purity aluminium powder. The lower explosion limit concentration of aluminium alloy polishing waste dust is 150 g/m3, which is 53.33% of that of high-purity aluminium powder. According to the analysis of the SEM image, the main reason is that the spherical particles of high-purity aluminium dust have a folded surface and good dispersion. Compared with the smooth fibre surface of aluminium alloy polishing waste dust, the former is easier to contact with air and the contact area is larger. Therefore, in engineering practice, it is not appropriate to use high-purity aluminium dust-related explosion parameters as the basis for the risk assessment of combustion and explosion at aluminium alloy polishing work sites. In addition, as the dust concentration decreases, the combustion intensity of high-purity aluminium dust and aluminium alloy polishing waste dust also decreases, and the flame propagation appears to be a discontinuous phenomenon. The peak flame propagation velocity of aluminium alloy polishing waste is 7.368 m/s at a concentration of 300 g/m3, which is 56.85% of that of high-purity aluminium powder. As the inerting ratio increases, the propagation velocity of the explosion flame slows down. When the inerting ratio reaches 30%, the minimum ignition energy of aluminium alloy polishing waste is inerted to 1 J, and self-sustained flame propagation cannot be formed. The results show that the ultra-fine Al(OH)3 powder has a significant inerting effect and is a realistic possibility in the production of aluminium alloy polishing.

Minimum ignition energy (MIE) of dust cloud is the core parameter to evaluate the explosion risk of combustible dust, and its test accuracy is important for dust explosion control. However, there are various methods to measure the minimum ignition energy, and the test results have many influencing factors, which is not conducive to control dust explosion. The principles and properties of different methods in the stages of dust dispersion, electrostatic spark generation, spark energy calculation and MIE determination were introduced. The influence of dust characteristics, dust dispersion states, spark generation parameters and test environment on the MIE test of dust cloud were discussed. The research hotspots of recent five years in this field were summarized and suggestions for future research were proposed. [ABSTRACT FROM AUTHOR]

Environmental perception is an important research direction of coal mine sustainable development. There is much dust in the underground working environment of coal mine. This study is to identify the marker (ball) in the coal mine, which provides a basic to convert the coordinate of large-scale fully mechanized mining face point cloud to the geodetic coordinate. Firstly, in the face of the phenomenon that the uneven distribution of underground point cloud is more serious, this study further has studied on the basis of complete and incomplete geometry point cloud and generated multi-density geometry point cloud for the first time. Secondly, aiming at the problem that the geometric features of underground point cloud are not obvious enough, this study has increased the weight of point cloud normal vector in the training process of network model, so that the network model is more sensitive to different geometric features. Finally, this study has used a variety of advanced deep neural networks to directly analyze point clouds to verify the proposed method. The results show that the method proposed in this study has been combined with the dynamic graph convolution neural network (DGCNN) established earlier, which can more accurately identify the ball in tens of millions of the point clouds of coal mining process. Most importantly, this work is not only of great significance to improve the production efficiency and safety in fully mechanized mining face but also lays a foundation for realizing intelligence in the mining field and avoiding the harm of dust explosion and other accidents to workers. [ABSTRACT FROM AUTHOR]

An organic dust explosion is a heterogeneous system on a space and time scale. Predicting the parameters characteristic of its severity needs experimental and theoretical approaches to find the optimal compromise between consistency with reality and modelling time. A hybrid method is proposed to study flash pyrolysis and combustion of several organic powders (cellulose, wheat starch, oak wood, Douglas fir and olive pomace). A Godbert-Greenwald furnace was employed to perform the experiments to mimic the fundamental characteristics of a dust explosion: high particle heating rate, high reaction temperature and short residence times. At 973 K, the residence time is a critical parameter: the large particles of cellulosic compounds (wood, cellulose) do not reach their pyrolysis temperature and only fibres smaller than 20 or 30 µm are fully converted. As the particle size distribution of starch is smaller, heat transfer is not directly the limiting phenomenon but rather the strong tendency for powders to agglomerate during pyrolysis. At higher temperatures, secondary reactions of primary tars are evidenced, stressing the influence of the pyrolysis stage and leading to heterogeneous combustion. The composition of the pyrolysis gases as a function of the nature of the powder and the temperature was also determined. A lumped-kinetic model adapted to dust explosion was developed and validated for cellulose. The kinetics constants corresponding to levoglucosan to permanent gases and cellulose to char and water reactions are significantly different from those proposed by the literature, demonstrating that dust explosion kinetic parameters must be obtained under conditions consistent with such phenomenon. [Display omitted] [ABSTRACT FROM AUTHOR]

Dust explosions can occur when the dust exceeds its minimum explosible concentration (45–150 g m−3) in the presence of confinement, oxidiser, dispersing agent, and an ignition source. These components have long been documented in the literature but studies on dust properties that affect suspension in confined spaces, such as flowability and floodability, are lacking. To address this, dust samples from five grain types (wheat, maize, soybean, rice, and milo) with particle size <450 μm were obtained and tested using five replicates for mean particle size, particle size distribution, and various shape characteristics (high sensitivity circularity, convexity, elongation, solidity, and aspect ratio) using Morphologi G3. Flowability and floodability indices were determined using Carr indices chart based on aerated and packed bulk density measurements; angles of repose, spatula, fall, and difference; compressibility; cohesion; and dispersibility in the Hosokawa Powder Tester PT-R. Results showed significant differences in packed bulk density, cohesion, elongation, and aspect ratio among the five grain dust types. Soybean dust exhibited the highest flowability (34.70) and floodability (64.25) indices suggesting the need for rotary seals to prevent dust from escaping which may further lead to dispersion into confined spaces, while milo dust exhibited the lowest (flowability index, 11.60; floodability index, 9.70). A very strong positive correlation was observed between dispersibility and floodability index and a very strong negative correlation between cohesion and flowability index. The results of the study contributed to the understanding of grain dust properties and their release into the atmosphere. Quantifying these properties is important for creating better grain handling procedures for improved health and safety. [Display omitted] • Wheat, maize, soybean, rice, and milo dust were tested and characterised. • Soybean dust exhibited the highest flowability and floodability indices. • Milo dust exhibited the lowest flowability and floodability indices. • Compressibility, cohesion, and dispersibility affected the floodability index. • Cohesion and angle of difference affected the flowability index. [ABSTRACT FROM AUTHOR]

In order to investigate the explosion mechanism of sucrose in the air atmosphere, the explosion intensity under different ignition delay times (IDT), powder input pressures (PIP), and concentrations were studied using a 20L-sphere. The sucrose particles were analyzed in a synchronized thermal analyzer (STA) and scanning electron microscope (SEM). The results are as follows: 1. The DSC curve has two endothermic peaks and one exothermic peak, respectively at T = 180.5 ℃, 510.2 ℃ and 582.6 ℃. 2. The explosion intensity varies with the experiment conditions. The maximum explosion pressure (Pmax) appears when IDT = 90 ms, PIP = 1.5 MPa and concentration = 625 g/m3. 3. The explosive mechanism is a homogeneous combustion mechanism based on particle surface pyrolysis and volatilization. Because of the decomposition, H2, CO, furfural, and other flammable gas-phase products are released, then surface burn appears, which leads to the crystal rupture on account of thermal imbalance, resulting in multiple flame points and a chain explosion. As the temperature of the 20L-sphere rises, more explosive products are released, which causes a rapidly expanding explosion and eventually forms the explosion. This paper can be used as a reference for the prevention of explosion accidents in sucrose production processing. [ABSTRACT FROM AUTHOR]

To address the concern of fire and dust explosions in wood processing facilities, the charging behavior on wood dust particles and air hoses during the air-blow cleaning operation were investigated. The effective work function, unit weight and surface roughness were key parameters influencing the charge accumulation on air hoses. The use of compressed air with lower velocity and higher moisture content could reduce the charge generation on airborne wood particles. Particle size, shape and wood species affect the charging behavior of wood dust. Conductive surface and moisture could help charges to be dissipated fast from wood dust particles. • Charge generation on wood dust depends on air velocity, humidity, and contact material. • Some species of wood dust tend to generate more charge than the others. • Charge on dry wood dust decays very slowly on all tested surfaces. • Moisture and grounding could speed up the charge decay. • The effective work function, unit weight and surface roughness affect charge accumulation on air hoses. [ABSTRACT FROM AUTHOR]

Epoxy (EP) powder is widely used in the industrial field of electrostatic coating due to its excellent physicochemical properties. However, the dust explosion risk caused by its flammability cannot be ignored. Calcium carbonate (CaCO 3) is often added into EP as an inorganic fillers because of its low cost and wide availability. This study explores the effects of different proportions of CaCO 3 on the explosion characteristics and pyrolysis behavior of EP powder. The results show that the maximum explosion pressure (P max), the minimum ignition energy (MIE), and the minimum ignition temperature (MIT) of EP are 6.82 bar, 6 mJ, and 460 °C, respectively. The addition of CaCO 3 reduces the explosion sensitivity and severity of EP dust to a certain extent. The thermal decomposition of CaCO 3 absorbs heat and produces CaO and CO 2. This process hinders the oxygen transfer, and dilutes the flammable volatiles, thereby reducing the explosion hazard of EP dust. [Display omitted] • The explosibility of Epoxy (EP) powder is measured as St-2 level. • The addition of 50 % CaCO 3 to EP dust effectively mitigates the explosion hazards of EP dust. • This study investigates the dust explosion mechanisms of EP and EP-CaCO 3. [ABSTRACT FROM AUTHOR]

[Display omitted] • Changes in turbulence caused by obstacles can lead to abnormal acceleration of FSV. • Established PSO-XGBoost model for predicting FSV of combustible dust. • The GBoost model shows high-precision (R2 = 0.98) predictions. • Ranking the importance of FSV using a random forest model. Corn starch powder is highly flammable and explosive, presenting significant safety hazards of dust explosions when encountering obstacles during its production and processing. This study indicate that with an increase in the number of obstacles, obstacle blockage ratio, and dust concentration, both the average flame spread velocity (AFSV) and the maximum flame spread velocity (MFSV) initially rise and then decline. However, the presence of obstacles significantly enhances both MFSV and AFSV compared to the absence of obstacles. Additionally, Using the Extreme Gradient Boosting (XGBoost) algorithm, predictive models for the MFSV and AFSV of corn starch dust were developed. By employing the Particle Swarm Optimization (PSO) algorithm for hyperparameter tuning, the model achieved an coefficient of determination (R2) of 0.9821 for MFSV and 0.9687 for AFSV, enabling highly accurate flame spread velocity (FSV) predictions. Random Forest importance analysis revealed that obstacle characteristics exert a more pronounced impact on FSV. [ABSTRACT FROM AUTHOR]

In order to investigate the flame propagation and pressure characteristics of dust particles during airflow transportation, a dust explosion experimental apparatus simulating dust handling processes was designed. The system is supplied with a stable airflow by a high-pressure fan, capable of continuously transferring dust from the vessel to the pipeline at a controllable speed. Dust explosion experiments were meticulously executed by applying 1 kJ of ignition energy to the transported dust particles at airflow velocities of 5, 10, and 15 m/s. This study examines the effects of airflow velocity, pipe diameter, and ignition position on explosion characteristics and delves into the mechanisms of these effects through a detailed analysis of experimental results. For the maximum explosion pressure, an increase in airflow velocity causes the maximum explosion pressure to rise. As the pipe diameter increases, the maximum explosion pressure first rises and then falls. The maximum explosion pressure occurs in the case of bottom ignition. The range of maximum explosion pressure values is expected to provide a reference for explosion detection and explosion venting. For flame propagation, the flame undergoes five processes within the vessel, including ignition of dust particles, spherical flame development, flame stretching towards the mouth of the pipe, complete combustion of particles, and near exhaustion of particle combustion. The higher the airflow velocity and the larger the pipe diameter, the more pronounced the flame stretching and development towards the pipe opening become. Within the pipe, two distinct flame propagation behaviors were observed under conditions of high and low airflow velocities. Compared with the experimental results of high-pressure pneumatic powder spraying forming a dust cloud within a vessel-pipeline, this study measures the maximum explosion pressure at specific turbulence levels and establishes a quantitative relationship between airflow velocity and explosion characteristics. Utilizing this correlation can provide a reference for predicting industrial-grade dust explosion characteristics at different airflow velocity levels, thereby offering a more optimized design basis for the design and safety protection of industrial equipment. [Display omitted] • Studied the impact of airflow velocity on dust explosions during pneumatic transport. • The coupling relationship of flame in vessel and pipe is studied during pneumatic conveying. • Airflow augments flame propagation speed and explosion pressure in dust deflagration. [ABSTRACT FROM AUTHOR]

A simulation investigation on the flow domain and particle movement pattern in the dispersion stage of dust explosion experiment were conducted using CFD simulation based on Euler–Lagrange approach. A new solver that couples two phases was developed based on the default solver rhoPimpleFoam from the OpenFOAM tool kit. Three sizes of particles 25 μ m , 125 μ m and 250 μ m were simulated and studied. The simulation results of dust front propagation were evaluated by the experiment data. Particles with smaller diameters tended to move slower. Due to the high turbulence, flow vortices in the lower part of the dispersion domain were identified. These vortices gradually became larger with time and the decrease of inflow velocity. Uneven distribution of particles along with the equipment and high concentration of particles between the discharge electrodes were found in the simulation. Furthermore, particles with higher velocity favored the middle position in the tube. These facts suggested that the ignition delay time for particles larger than 125 μ m should be higher than 60 ms. [ABSTRACT FROM AUTHOR]

Dry dust collectors are a typical dust and gas coexistence space. Dust explosion risk assessments should be performed for effective prevention and control of dust explosion accidents. In this paper, a dust explosion risk assessment index system for dust removal systems was constructed following the dust characteristics and the actual operation of a dry dust collector. The proposed system consisted of three first-level indexes (dust explosion characteristic parameters, environmental parameters in the dust collector box, use state of explosion prevention and control device) and seven second-level indexes (dust explosion sensitivity, dust explosion severity, temperature in the dust collector box, pressure difference between inlet and outlet, operating state of spark detection, operating the explosion venting disc, and operating state of the lock gas ash discharge valve). The analytic hierarchy process was adapted to calculate the weight of each index. Additionally, a dust explosion risk assessment model for the dust removal system was constructed using the fuzzy comprehensive evaluation method to form a set of dust explosion risk assessment methods suitable for dry dust collectors. The risk of explosion was assessed at level II through the use of paper powder with a particle size of 75 μ m, which means this method is reliable. [ABSTRACT FROM AUTHOR]

Explosion isolation flap valves are one of the most used explosion protection systems in process industries; research is essential to improve them and to minimise both human and material losses when dust explosions take place. In this regard, there is little knowledge on the effect of bends in the functionality of these protective systems; hence, the main aim of this work is to bridge this gap. Large-scale dust explosions were performed, using three different types of dust: metal dust and two types of organic dust. In order to analyse the effect of bends in the functionality of these protective systems, results using a straight duct and one with bends were compared for each dust tested. In addition, the influence of the bend radius on aluminium dust explosions was also evaluated. The results indicated that the effect of bends depended on the explosive characteristics of the dust. However, for aluminium and maize starch dusts, bends led to higher pressures and flame velocities. Relevant information is provided to help decision-making when designing these valves. Moreover, such data can be used for consideration in the discussions held by the task force entrusted with developing the standard used to assess their functionality. [ABSTRACT FROM AUTHOR]

In metallurgical processes, coke is used, among other materials, in order to implement the process of removing zinc from waste by reduction and evaporation. Due to the implemented de-carbonization policy, we are dealing with an increase in costs and decreasing availability of coke, which leads to an intensive search for other possibilities for conducting the process, which may generate a fire and explosion hazard in the technological process. This article analyzes the possibility of using soot in the process of reducing the zinc content in deposited metallurgical waste, taking into account the issue of fire and explosion safety. The results of the research proved the possibility of the safe use of the reductor, which is soot and anthracite, as a material replacing coke in pyrometallurgical processes. [ABSTRACT FROM AUTHOR]

It studied the explosion propagation of the hybrid mixture of LDPE dust and a small amount of ethylene (below its LEL) in a closed duct, to examine the impacts of dust concentration, dust particle size, and ethylene concentration on flame propagation behavior and overpressure characteristics. The dust concentration affected the explosion behavior of the LDPE dust/ethylene hybrid mixture in two ways. The flame gradually became discrete and unstable as the dust concentration increased, while the maximum and average flame propagation velocity, Pmax, and (dp/dt)max increased first and then decreased. The dust particle size and ethylene concentration had a significant effect on the hybrid mixture explosion. As the particle size decreased or the ethylene concentration increased, the discrete flames quickly merged into a bright continuous flame. Further, the maximum and average flame propagation velocity, Pmax, and (dp/dt)max increased, whereas the fluctuation degree of the flame propagation velocity with time showed a decreasing trend. There was no obvious agglomeration phenomenon among small LDPE particles. The explosion overpressure and flame propagation showed a strong synergistic effect. Compared with the semi-open duct, the closed duct with a more uniform dust/gas hybrid mixture showed a more continuous flame structure, a shorter flame propagation distance, and a lower flame propagation velocity. These conclusions can provide a scientific basis for explosion risk analyses and process safety designs involving the production of LDPE powder. [ABSTRACT FROM AUTHOR]

Experimental investigations of dust explosions in standard industrial testing equipment such as the MIKE3 minimum ignition energy (MIE) testing device are promising ways of producing fundamental insights into dust cloud ignitability. However, advanced experimental methods must be developed to characterize the dust cloud ignition and combustion behavior of various types of dust. In this work, high-speed broadband and species-specific chemiluminescence imaging diagnostics are implemented to explore similarities and differences between organic and metal powder ignition kernel development. A selected set of 600-mg niacin (ϕ = 2.9) and aluminum (ϕ = 1.6) powder samples were dispersed in the air and ignited using a high-voltage spark inside a standard MIKE3 device. The resulting broadband flame emission was recorded at 4 kHz using a high-speed camera for the first 10 ms after the spark. For the niacin sample, species-specific chemiluminescence emissions from excited-state hydroxyl (OH*) and methylidyne (CH*) radicals were also recorded at 4 kHz and 1 kHz, respectively. The flame kernel in each image frame was detected using an intensity thresholding algorithm and tracked throughout the video sequence, yielding quantitative size, position, and velocity measurements of the evolving flame kernel during the first 10 ms after the ignition spark. For the niacin sample, a continuous and non-uniform reaction zone composed of burning particle clusters and excited-state radicals was observed. The niacin flame kernels grew from 5 mm to 17 mm with an initial velocity of 5 m/s. Conversely, an intensely bright reaction zone and discrete burning particles near the flame kernel boundary were observed in the aluminum sample. The aluminum flame kernels grew from 7 mm to 10 mm with an initial velocity of 3 m/s. The niacin and aluminum flame kernels traveled 7–11 mm away from the central spark gap and slowed down to 1 m/s by the end of the 10-ms period. This time-resolved imaging study, when coupled with previously reported three-dimensional particle and flow field data prior to the arrival of the ignition spark, sets the foundation for an improved multi-physics understanding of the initiation of dust cloud ignition and explosion processes. [ABSTRACT FROM AUTHOR]

Monitoring the dust cloud dispersion process inside testing equipment like the MIKE3 minimum ignition energy device is useful for assessing the ignitability characteristics of different dust materials. However, it is difficult to comprehensively capture the relevant micro-scale particle properties and macro-scale flow behavior of a dust cloud dispersion using a single measurement method. Thus, the objective of this work is to combine two complementary laser diagnostic techniques to obtain quantitative particle and flow properties from dust clouds in the MIKE3 glass tube. For this experiment, thirty repeated runs for each method were conducted using small (15-mg) aluminum powder samples. No ignition electrodes are included in the test geometry to establish a baseline flow configuration for the glass tube, although measurements are still made at the characteristic time delay and location of ignition tests. The first technique, digital in-line holography (DIH) is used for three-dimensional micro-scale particle diagnostics, yielding particle number (n = 78 ± 20), size (D ̅ = 18.9 ± 0.6 µm), and three-component velocity ( v ̅ x = 0.05 ± 0.05 m/s, v ̅ y = 0.60 ± 0.09 m/s, v ̅ z = − 0.07 ± 0.16 m/s) measurements. The second laser diagnostic technique, particle image velocimetry (PIV), is used for macro-scale flow diagnostics, yielding two-dimensional flow velocity and vorticity vector field measurements. Particle sizes are observed to follow a lognormal distribution (μ = 2.89, σ = 0.31), and a discrepancy between in-situ and ex-situ sizing results is identified for particle sizes larger than ~55 µm. Two-dimensional particle velocities follow a Weibull distribution (θ = 0.86, β = 2.12), and reasonable agreement is found between the DIH and PIV velocity measurements. [ABSTRACT FROM AUTHOR]

A large amount of waste dust will be produced in the process of metal grinding, resulting in a waste of resources and environmental pollution. Therefore, we present a new method of inerting waste aluminum (Al) alloy dust for recycling purposes. Three natural high polymers—starch, pectin, and hydroxypropyl cellulose—were selected to inert waste metal dust in order to prevent the alloy from hydrolyzing and keep the dust pure enough for reuse. The particles of the Al base alloy before and after dust reaction were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infra-red (FTIR), and the relevant reaction mechanism was clarified. The hydrogen evolution test indicated that, across the temperature interval of 313–333 K, 0.75 wt% pectin inerted hydrogen evolution most efficiently (90.125%). XRD analysis indicated that the inerted product is composed of Al monomer and Al3Mg2, with no detectable content of Al hydroxide. The purity of the Al alloy dust was preserved. SEM and FTIR analyses indicated that the -OH, -COOH, and -COOCH3 functional groups in the high polymer participated in the coordination reaction by adsorbing on the surface of the waste Al alloy particles to produce a protective film, which conforms to Langmuir's adsorption model. Verification of the inerted Al alloy dust in industrial production confirmed the possibility of reusing waste Al alloy dust. This study provides a simple and effective method for recycling waste Al alloy dust. [ABSTRACT FROM AUTHOR]

This paper examines dust explosion characteristics and mechanisms for aluminum powder (Alp) in four different low-concentration hydrogen environments (0%, 1%, 2%, and 4 vol%). The aluminum powder's combustion characteristics were determined and the minimum ignition temperature and minimum ignition energy were found to be 690 °C and 45 mJ, respectively. A 20-L apparatus was used to evaluate how the explosive characteristics varied under different hydrogen concentrations. The explosion pressure generated by 4 vol% H 2 was ca. 8.3% stronger than an explosion in the air, and the explosion pressure rise rate showed an increase of 48%. In addition, the time to maximum rate of pressure rise was shortened in the mixed Alp/hydrogen experiment. The experimental residues were observed, and from this it was inferred that the explosion mechanism changed when a low concentration of H 2 was present. [Display omitted] • Defined the characteristic combustion and explosion parameters of Al powder. • Acquired Al powder explosion data for four different H 2 concentrations. • Inferred the explosion mechanism for Al powder mixed in the presence of low-level H 2. • Analyzed residual Al powder samples after an explosion involving low-level H 2 concentrations. [ABSTRACT FROM AUTHOR]

Dust explosions are a major concern in many industrial facilities and particularly in storage areas of biomass materials. Although venting standards (EN 14491 and NFPA 68) provide satisfactory safety levels for most industrial applications, they present some limitations and there exist situations that they do not contemplate. Vented dust explosions in a 4500 m3 silo for the storage of wood pellets were simulated by computational fluid dynamics. Maximum overpressures were registered and compared. The influence of several parameters including initial turbulence level, dust concentration, ignition location, and vent area was studied. A factorial analysis was carried out to determine the importance of each of the four parameters, along with possible interactions between them. The results showed great variations in the overpressures between the different scenarios simulated. Vent area, ignition location, and dust concentration showed similar effects on the overpressure (around 25%), while initial turbulence had half this effect (13%). One interaction effect out of the eleven possible interactions was identified as relevant for this specific industrial scenario: the combination of the ignition location and the initial turbulence, with an additional effect of 5% on the overpressure. The factorial analysis applied in this study could be of interest to the risk assessment of industrial facilities.

[Display omitted] • Micro–dust poses a higher explosion risk than nano-sized under specific conditions. • The flame propagation behavior in interconnected vessels is investigated. • Explosion mechanism of PMMA dust cloud in interconnected vessels is analyzed. The overpressure characteristics and explosion mechanism of micron and nano polymethyl methacrylate (PMMA) dust in interconnected vessels were studied with different pipe diameters, pipe lengths and volume ratios. The results show that 150 nm PMMA dust exhibits more intense explosion intensity. Relative to 30 μm PMMA particles, the explosion overpressure is more significantly affected by the pipe diameter due to the faster combustion rate for 150 nm PMMA particles. The increase in volume ratio positively affects the increase of explosion overpressure, and the highest increase is 463 % for 30 μm PMMA. Due to the change in the relative relationship between energy loss and combustion heat release in the pipe, the explosion intensity of 150 nm PMMA with different pipe diameters increases to a certain extent with the increase of pipe length, while the explosion intensity of 30 μm PMMA decreases. Under identical circumstances, the 150 nm PMMA dust cloud inside the second vessel failed to ignite, while the 30 μm explosion successfully diffused into the second vessel. The explosion in the second vessel is mainly due to the different flame energy entering the second vessel. The heat transfer rate between the single 30 μm PMMA particle and the external environment is significantly higher than 150 nm, resulting in an instantaneous quenching of the 30 μm PMMA flame front at the initial entry stage into the pipe. [ABSTRACT FROM AUTHOR]

As modern industry evolves, powder technology has become widely used across numerous sectors. However, such extensive utilization has augmented the risk of dust explosions due to electrostatic charges during the production processes. The tiny size of dust particles, along with their tendency to gather static electricity during transportation in pipelines, poses a significant challenge for both observation and analysis. Furthermore, the electrostatic charging mechanisms of dust particles are still not well understood, highlighting the urgent need to clarify how electrification occurs to effectively mitigate electrostatic issues with dust. In this paper, a continuous gas-solid two-phase flow triboelectric nanogenerator (GS-TENG) has been developed to explore the generation mechanism of triboelectrification when flour-air two-phase flow collides with pipeline wall. Furthermore, to comprehensively analyze the relationship between flour movement in the pipeline under the influence of airflow and frictional electric signals, high-speed cameras were employed to record flour motion throughout the process. The findings indicate that flour-air two-phase flow exhibits unidirectional frictional electric signals after friction within PTFE pipelines. The findings reveal that the flow of flour driven by airflow through PTFE pipes produces frictional charges, leading to the formation of charged clusters. Upon contact with a grounded copper mesh, electric current peaks of up to 150 μA can be observed. Since the frictional charges carried by flour primarily originate from wall friction, coating the inner walls of pipelines with silicon-modified acrylic resin significantly reduces the frictional charges carried by flour, effectively suppressing static electricity accumulation and discharge phenomena, thus enhancing the safety of dust transportation. This study offers novel strategies for harnessing frictional electricity in gas-solid two-phase flows and mitigating electrostatics. [Display omitted] • An adjustable gas-solid two-phase flow TENG system was constructed. • GS-TENG can test the charging status of flour particles in situ. • A method to suppress the charging behavior of flour particles is proposed. [ABSTRACT FROM AUTHOR]

Incense is an indispensable material with religion and life in Asia. It is also a bridge of cultural expression and inheritance. Because the operating environment concentration of dust generated during the production process is considerable, most of the research pertaining to the hazard of incense factories has investigated air pollution, such as PM2.5, PM10, and VOCs. However, the production of incense causes dust dispersion, high temperature from ovens, and static electricity generated by friction. It can all possibly lead a dust explosion. To prevent and alleviate hazard from re-occurring, we used sandalwood dust at an incense factory in Taiwan, measured the effect of moisture content on the explosion parameters under normal conditions by 20-L apparatus, and used the oven to diminish its moisture content to 0%, 10.0%, and 15.0% as a control group to analyze the explosion characteristics at the different moisture contents, such as maximum explosion pressure and explosion limit. The results showed that the minimum ignition energy of dry dust was 30 mJ. Beyond doubt, incense factories face potential explosion hazards. The above results could be evaluated by the most dangerous range to avoid incense dust in this range at the workplace, lessening hazards caused by a dust explosion. The effect of moisture content on the suppression of the dust explosion was explored. [ABSTRACT FROM AUTHOR]