Dust Explosion Research Research Articles

Analysis on research trends with dust explosions by bibliometric approach

Highly destructive combustible dust explosions, which is prone to cause secondary explosion, has been a concern in industrial processes. To understand the current development and status of research on dust explosions, 1276 publications related to dust explosions from 1998 to 2021 were indexed through the Web of Science Core Collection database. CiteSpace and VOSviewer were used to visualize and analyze the collected literature information. The number of articles related to dust explosions has increased from 12 in 1998 to 191 in 2021. China, the United States, and Canada are the major contributors in this field. Dalhousie University, Beijing Institute of Technology, and Dalian University of Technology are at the core of dust explosion research. Wei Gao, Paul Amyotte, and Chi-Min Shu are the most prolific researchers. Journal of Loss Prevention in the Process Industries, Powder Technology, and Process Safety and Environmental Protection are the major sources of publications related to dust explosions. The research topic of dust explosions mainly evolves into four aspects: explosion characteristics and influencing factors, research media, explosion suppression, and numerical simulation. New research hotspots have appeared related to gas–dust hybrid mixtures, nanomaterials, and powder suppressants. The results can help researchers in the dust explosion field to quickly determine the research frontier and the overall situation.

Classification of dispersibility for combustible dust based on Hausner ratio

Mixing of combustible dust and oxidant is one of five essential prerequisites in the dust explosion pentagon, requiring that particles originally in mutual contact within the deposits be separated and suspended in the air. However, dust dispersion never proceeds with 100% efficiency, with inevitable particle agglomeration, and an inherent trend toward settling out of suspension. Dispersibility is defined to describe the ease of dispersion of a dust and the tendency of the particulate matter to remain airborne once a dust cloud has been formed. Pioneers made contributions to classify dust dispersibility by introducing dustiness group (DG), dustability index (DI), NIOSH dispersion chamber and in-situ particle size analysis. Issues remained including the difficulty in comparing results from different methods, as well as the availability of some high-tech testing apparatus.This study aims to provide a quick and universal testing method to estimate the dispersion property of combustible dust. A new dispersibility classification was developed based on dimensionless numbers Hausner ratio and Archimedes number. Four dispersibility classes (DCs) were proposed from one to four, with a larger number meaning better dispersibility. Results for more than a dozen dust samples and mixtures thereof showed the new method is useful in dust explosion research. The consistency in classifying dust dispersion properties between the DC method and previous methods was good. Changes in DC well explained our earlier findings on suppressant enhanced explosion parameter (SEEP) phenomenon attributed to the improvement in dust dispersibility. Hausner ratio and Archimedes number, as easily measured parameters, can be quite advantageous to assess dust dispersibility, permitting a proper risk assessment for the formation of explosible dust clouds.

High-speed digital in-line holography for in-situ dust cloud characterization in a minimum ignition energy device

Precise measurement of the minimum ignition energy (MIE) of combustible dust is crucial to safety in the process industries. The development of comprehensive methods for MIE dust cloud characterization is therefore highly desirable. The objective of this study is to investigate the application of high-speed digital in-line holography (DIH) for volumetric and in-situ characterization of dust clouds near the ignition zone of a Kühner MIKE3 MIE device. The dispersion behavior of borosilicate glass and soda-lime glass dust clouds are studied at 20 kHz. Size measurements, with successful detection down to 13 μm, are compared with Beckman Coulter particle size analyzer results. The 5-ms hologram videos also yield new transient particle volume, concentration, and velocity measurements. Sample sizes of 15–150 mg of dust powder are sufficient for each high-speed run. This work showcases new diagnostic capabilities that are accessible to dust explosion research and identifies areas for future research.

Dust Explosions in the Process Industries: Research in the Twenty-first Century

Accidental dust explosions pose a threat to personnel and property in industries that produce, process, handle or transport combustible dusts. Over the last decade, the international research community has made significant progress towards improved understanding of the dust explosion phenomenon. This has resulted in improved standards and best practice guidelines for safe operation, as well as increased awareness of the inherent limitations in test procedures and methods for extrapolating results from laboratory experiments to industrial scales. Of particular importance is the development in the field of numerical modelling of dust explosions, and the accompanying need for reliable validation data from large-scale experiments. The purpose of the paper is to review the development and trends in dust explosion research in the twenty-first century, with particular emphasis on numerical modelling of flame propagation in dust clouds and the application of advanced models for risk assessment and risk management in the process industries.

A constant pressure dust explosion experiment

A new apparatus has been designed for investigating flame propagation in turbulent dust clouds at near constant pressure conditions. The experimental approach is inspired by the classical soap bubble method for measuring burning velocities in gaseous mixtures. Combustible dust is dispersed with pressurised air to form an explosive mixture inside a transparent latex balloon. After a certain delay time, the turbulent dust cloud is ignited by a 40 J chemical igniter. A digital high-speed video camera records the propagating flame and the expansion of the balloon. Experiments were performed with two types of dust, Lycopódium spores and maize starch, as well as with propane–air mixtures under initially quiescent or turbulent conditions. Although the results are primarily qualitative in nature, they nevertheless demonstrate fundamental differences between premixed combustion of gaseous mixtures, and ‘premixed combustion with non-premixed substructures' in mechanical suspensions of solid particles dispersed in air. The discussion highlights some fundamental challenges for future dust explosion research.

Current status and expected future trends in dust explosion research

In spite of extensive research and development for more than 100 years to prevent and mitigate dust explosions in the process industries, this hazard continues to threaten industries that manufacture, use and/or handle powders and dusts of combustible materials. Lack of methods for predicting real dust cloud structures and flame propagation processes has been a major obstacle to prediction of course and consequences of dust explosions in practice. However, work at developing comprehensive numerical simulation models for solving these problems is now on its way. This requires detailed experimental and theoretical studies of the physics and chemistry of dust cloud generation and combustion. The present paper discusses how this kind of work will promote the development of means for prevention and mitigation of dust explosions in practice. However, progress in other areas will also be discussed, e.g. ignition prevention. The importance of using inherently safe process design, building on knowledge in powder science and technology, and of systematic education/training of personnel, is also emphasized.

Experimental mine and laboratory dust explosion research at NIOSH

This paper describes dust explosion research conducted in an experimental mine and in a 20-L laboratory chamber at the Pittsburgh Research Laboratory (PRL) of the National Institute for Occupational Safety and Health (NIOSH). The primary purpose of this research is to improve safety in mining, but the data are also useful to other industries that manufacture, process, or use combustible dusts. Explosion characteristics such as the minimum explosible concentration and the rock dust inerting requirements were measured for various combustible dusts from the mining industries. These dusts included bituminous coals, gilsonite, oil shales, and sulfide ores. The full-scale tests were conducted in the Lake Lynn experimental mine of NIOSH. The mine tests were initiated by a methane–air explosion at the face (closed end) that both entrained and ignited the dust. The laboratory-scale tests were conducted in the 20-L chamber using ignitors of various energies. One purpose of the laboratory and mine comparison is to determine the conditions under which the laboratory tests best simulate the full-scale tests. The results of this research showed relatively good agreement between the laboratory and the large-scale tests in determining explosion limits. Full-scale experiments in the experimental mine were also conducted to evaluate the explosion resistance characteristics of seals that are used to separate non-ventilated, inactive workings from active workings of a mine. Results of these explosion tests show significant increases in explosion overpressure due to added coal dust and indications of pressure piling.

Large scale grain dust explosions-research in Poland

For the last five years grain dust explosion research was carried out in surface and underground facilities of Experimental Mine “Barbara” Research was focused on problems of evaluation critical dust parameters influencing explosion course, explosion development and suppression by both passive and active means. The main conclusions are as follows: nominal dust concentration needed to obtain flame propagation must be higher than 50 g/m3, for nominal concentrations higher than 100 g/m3 flame acceleration is observed and detonation is possible; strong grain dust explosions can be effectively suppressed with passive water barriers whereas for weak ones active barries must be used.

Dust explosion research. State-of-the-art and outstanding problems

Increased knowledge creates a justified request for a steadily more differentiated approach to design of preventive and mitigative measures against dust explosions in industry. In this process, cross-fertilisation between fundamental research and applied research and development is beneficial. Central research topics include formation of, ignition of and flame propagation in dust clouds, blast waves from exploding dust clouds, and test methods. Due to the complexity of the various problem areas, comprehensive theories are scarce. However, computer simulation models, carefully calibrated against experiments, may become useful tools in the future. Expert systems should be welcomed,but adequate Quality Assurance is essential.

Laboratory and large‐scale dust explosion research

AbstractThis paper describes dust explosibility research in full‐scale experimental mines and a 20‐L laboratory chamber at the U.S. Bureau of Mines and in a 1‐m3 laboratory chamber at Fike Corporation. The purpose of this research is to improve safety in mining and other industries that manufacture, process, or use combustible dusts. As part of this work, carbonaceous dusts with a wide range of volatilities and various particle size distributions were studied. Laboratory data on the minimum explosible concentrations of predispersed dusts were comparable to mine data for nominal dust loadings that were dispersed by the aerodynamic disturbance from a gas ignition zone. Recommendations are given on the limitations of small‐scale testing such as “overdriving” by too strong of an ignitor. The effect of dust particle size on explosibility data is illustrated for coal and aluminum dusts. For both dusts, the finest sizes were the most hazardous. The inerting requirements for preventing explosions were also measured in both laboratory and large‐scale systems. All the data show relatively good agreement between the laboratory and the large‐scale tests.

Dust explosion research in Poland

The review of basic and applied research in dust explosions in Poland is given. The importance of proper evaluation of explosive dust properties is discussed and a general overview of results obtained in the area of ignition, flame propagation and detonation is presented. A brief description of explosive hazard evaluation under industrial conditions is also given, with a short discussion of dust suppression research.

Research on dust explosions at the University of Michigan

Dust explosion research carried out at the University of Michigan during the last two decades has been summarized. Significant results are presented on the smoldering combustion of dust heaps, turbulent combustion of premixed dust clouds, entrainment and combustion of layered dust, and on shock wave ignition of particles and shock wave initiated detonative combustion. Also, information on the detonation of hybrid mixtures and gaseous mixtures containing nonreactive particles is given.

Contribution of low‐level flammable vapor concentrations to dust explosion output

AbstractAs a result of extensive dust explosion research, additional areas of hazards have arisen. The potential of combining small percentages of flammable vapors (below the lower explosion limit) introduces additional dust explosion hazards.