Factors affecting dust fire explosion probability factors that influence the dust fire explosion probability include the following. Pdf coal dust explosions in a spherical bomb gaetano. In cases when fuel plays the role of a combustible material, the explosion is known as a fuel. Here the fine coal dust generated due to mining pollutes both the water and atmosphere. Immediately afterwards, the occurrence of methane and coal dust in hard coal mining prompted the development of the basics of electrical explosion protection. Dilution is utilized is in the mining industry where limestone will be added atop a layer of coal dust to prevent a coal dust explosion if the two layers are disturbed.
Coal dust explosion prevention and protection based on. Plants can no longer sweep coal dust under the rug and ignore the health and safety hazard it presents, because a single spark can cause a dust explosion that could put a plant out of service. Smouldering fires are followed by an increase in co concentration in the headspace area of the bunker. How to make sure your dust collection system complies with. However, unavoidable abrasion across the whole transportation path, from conveying to the power plant and onwards to the combustion process, leads to fine coal dust.
In addition to these methods, other countries use both passive and active methane and coal dust explosion barriers, hygroscopic pastes to bind coal dust, and minewide atmospheric monitoring to. Size of dust particles 5200 microns pressure 5100 psi dust particles concentration 3550 gmsm3 oxygen level min. Dust particle size has the greatest influence on the propagation coal dust and inhibition rock dust of dust explosions. Group i high calorific value coal wk, 5% ash, 5% moisture, hhv about 30000 kjkg. The national institute for occupational safety and health niosh, as part of its continuing research program for evaluating coal dust explosion hazards, has investigated several areas in which current practices may need to be updated in order to adequately protect mines against coal dust propagated explosions. Cfd simulation of underground coal dust explosions and active. Research on characteristic parameters of coaldust explosion article pdf available in procedia engineering 45.
Coal dust suspended in air is explosivecoal dust has far more surface area per unit weight than lumps of coal, and is more susceptible to spontaneous combustion. Basically, from mining to coal cleaning, from transportation to electricity generation to disposal, coal releases countless volumes of dust into the air. Limiting the formation and dispersion of coal dust 18 8. There is experimental evidence that coal dust air mixtures do have a lower explosive limit i. The prevention and control of fire and explosion in mines. Also, proper pressure relieving vents and wall panels should be. It summarizes the presentday understanding of coal dust explosion hazards and presents a comparison of some national and international regulatory standards.
Your rock dusting solution for mitigating coal dust explosions. These two factors are taken as intermediate events of a fault tree, to conduct a further analysis and determine the various factors that influence the occurrences of such events. Fire and explosion prevention in coal pulverizing systems. The accident resulted in the death of all eight miners who were underground at the time. Finelydivided coal dust is a moderate fire and explosion hazard, particularly when dispersed in the air at high concentrations in an enclosed space and exposed to flame or other ignition sources. Despite implementing the most rigorous safety measures, the potential for coal dust explosions in underground coal mines must be mitigated by a generous application of rock dust usually in the form of limestone. Against this theory is the supposition that coal dust in the bunkers would be damp with condensation, as the steel hull was in constant contact with the. Preventing the formation andor accumulation of hazardous dust preventing the ignition of dust limiting the consequences of an explosion or fire mitigation and. Firefighters brought it under control at first, but it flared up again.
Firefighting precautions at facilities with combustible dust. If the mill is restarted without first removing the hot coal, an explosion can occur when particles are suspended and exposed to the inrushing combustion air. Coal dust explosion tests in the experimental mine 19 to 1918, inclusive. Clauses of the coal mines regulations relating to m 3006 mrts guideline for coal dust explosion prevention and suppression are indicated in the references section of the uideline.
Eckhoff, in explosion hazards in the process industries, 2005. Fire and explosion hazards in cement manufacturing industries. Distribution of temperature of explosion tw and ignition tz as a function of dust concentration results the following kinds of coal have been taken into consideration for investigating of explosion limits. Anatomy of a float coal dust explosion coal combustion front underlying rock dust dispersion lags behind the combustion front and unable to quench combustion front surface coal dust disperses first layered dust float coal dust 0. Combustible dust explosions combustible dusts are fine particles that present an explosion hazard when suspended in air in certain conditions.
How to make sure your dust collection system complies. Pdf hlobane colliery coal dust explosion risk management. Compliance with requirements relating to sampling and analysis of samples 19 8. This results in further heat buildup and the potential for a fire. Samples collected from the msha rock dust survey as discussed in the 2011 niosh hazard id, were multimodal, and several samples appeared to have wide variations in the amount of effective finer particles. Depending on the specific application, there are several standard procedures for determining mie of dust.
Pdf the dust explosion characteristics of coal dust in. A coal dust explosion is caused by a mixture of concentrations of coal dust and air that reaches the explosion limit and meets a hightemperature fire source. Mine safety and health admininstration pittsburgh, pennsylvania abstract there are a large number of facilities throughout the world which handle coal, such as preparation plants. While the ability of dust explosions to propagate has been widely recognized, some misconceptions lead to the false sense. When designing a dilution scheme, it is important to confirm that the. The result is heat, light, combustion gases and pressure. Overton said that this thinking was helpful to prevent and control dust explosion in the process industries 2. Management of coal dust explosions in united states coal. A wood dust explosion is a propagating moving combustion process in which an ignited dust particle ignites nearby particles and the flame proceeds from the ignition source through the premixed dust air atmosphere. Dust explosions can occur where any dispersed powdered combustible material is present in highenough concentrations in the atmosphere or other oxidizing gaseous medium, such as pure oxygen.
Report issued by the bureau of mines over experiments conducted on coal dust explosions. Mine safety, and later, the safety of coal pulverizing systems, have received much detailed attention. Dust explosion and fire prevention handbook wiley online books. Pdf effect of methane and coal dust concentrations on. Coal dust is a fine powdered form of coal, which is created by the crushing, grinding, or pulverizing of coal. The epartment of mineral resources document m 3006 mrts tr technical reference material for coal dust explosion prevention and suppression provides technical reference material for the uideline.
Jul 14, 2010 this is from a demonstration at a coal mine i taped. Coal dust iarc monographs on the identification of. Cfd simulation of underground coal dust explosions and. The regulations also contain requirements relating to barriers to the extension of flame.
A coal dust explosion has the potential to propagate throughout a mine resulting in massive damage to the mine and equipment, as well as tragic loss of life. This report includes tables, illustrations, and photographs. Fuelbituminous coal is the fuel typically used in a pulverized fuel system. Co is an odorless and very toxic gas and imposes a serious explosion thread at levels above 8. Assessment of gas and dust explosion in coal mines by means. Pdf research on characteristic parameters of coaldust. In many combustible dust incidents, employers and employees were unaware that. Jul 04, 2014 this handy volume is a ready go to reference for the chemical engineer, plant manager, process engineer, or chemist working in industrial settings where dust explosions could be a concern, such as the process industries, coal industry, metal industry, and others. The advantages of electricity were so convincing that intensive work was carried out to. Compliance with requirements relating to the design of barriers to prevents the propagation of coal dust explosions 19 8.
An assessment of current global regulations and practices uncovered four main control methods utilized to prevent coal dust explosions in coal mines worldwide. Because of the brittle nature of coal, coal dust can be created during mining, transportation, or by mechanically handling coal. Fire and explosion hazards in the handling of combustible. Particle size and surface area effects on explosibility. Two firefighters then climbed onto the roof and directed a water hose stream through a hatch. Settled dust on horizontal surfaces may also be dispersed into the air by an initial explosion, resulting in a much more serious secondary explosion. Dust explosion protection in a hard coalfired power plant. Standard for the prevention of fire and dust explosions. To prevent coal dust explosions and limit the amount of inhaled dust particles to reduce injury, limestone powder is sprayed along the walls of mines on a regular basis. The dust explosion characteristics of coal dust in an oxygen enriched atmosphere article pdf available in procedia engineering 45. Preventing coal dust explosions in underground coal mines. Mine safety and health specialist originating office mine safety and health administration 4015 wilson boulevard, arlington, virginia 22203. Types of dusts involved in dust explosions unknown 11,5% smolder spots 9% other 2,5% mechanical sparks 30% electrical equipment 3,5% static electricity 9% friction 9% fire 8% hot surfaces 6,5% selfignition 6% welding 5% figure 2. Electrical area classification in coalfired power plants.
Thanks to msha and the great personnel at the mine. Computational fluid dynamics cfd is being applied to the study of coal dust explosions and their suppression in underground coal mines. Department of the interior, bureau of mines, bulletin 167. Guideline for coal dust explosion prevention and suppression. Pollution due to coal starts from the mine head itself. The advantages of electricity were so convincing that intensive work was carried out to fi nd a way to reliably prevent contact between an explosive. Mitigating coal dust explosions in modern underground coal mines. The results of the experiments are presented and discussed. Aug 18, 2018 ideally, it is true to say that coal dust consists of a fine powdered form of coal thats formed when coal is crushed, ground, blasted, drilled or pulverized, considering its brittle nature. In the event of an explosion, the surface limestone layer absorbs heat that is generated from the explosion. In practice, a fire occurring during normal pulverizer.
Jul 15, 20 demonstration by msha at the sunrise coal llc, carlisle mine. Coal dust fires and explosions the pioneering effort to establish the relative ignition sensitivity and explosibility of air and various flam mable dust mixtures was carried out by the u. It was shown that an explosion in the primary vessel can result in explosion propagation and cause a much more violent explosion in. As a result, a nearly empty coal store is a greater explosion risk than a full one. Many other facilities use coal as a fuel, such as cement and lime factories. Department of the interior, bureau of mines, ri 8077.
The coal is largely so coarsegrained that there is no immediate risk of dust explosion. Therefore, it is very significant to prevent and mitigate dust explosion intrinsically with the thinking of inherent safety. Trying to bring about more caution to miners after. Identifying improved control practices and regulations to. The coal mines precautions against inflammable dust regulations 1956 set out requirements for the maintenance of incombustible matter in mine roadway dust including sampling, sample analysis, type of analysis and keeping records of analyses. Illustrative dust explosion incidents are highlighted in grain handling, food processing, coal mining, wood processing, metal working, and pharmaceutical component manufacturing industries. Coaldust explosion tests in the experimental mine 19. The subject of this monograph is coal dust, itself a heterogeneous byproduct of the mining and use of coal. Coal operators conference faculty of engineering and information sciences 2010 cfd simulation of underground coal dust explosions and active explosion barriers david humphreys skillpro services greg collecutt bmt wbm david proud bmt wbm research online is the open access institutional repository for the university of wollongong. Particle size and surface area effects on explosibility using. It is a form of fugitive dust grinding coal to dust before combusting it improves the speed and efficiency of burning and makes the coal easier to handle. Explosion pressure rate rise dpdt experiments for coal dust and methane coal dust air hybrid mixtures in a modified 20 l explosion apparatus were conducted to provide data on explosion characteristics in ventilation air methane vam systems.
Resources document m 3006 mrts tr technical reference material for coal dust explosion prevention and suppression provides technical reference material for the uideline. Dust explosion protection in a hard coalfired power plant in. The torpedo could have kicked the coal dust into the air, and much like the aluminum powder theory, would have reached explosive concentrations as it settled, triggering the second explosion. If an explosion does occur, the rock dust disperses and mixes with the coal dust, preventing flame propagation by acting as both a.
Coal dust explosions are still occurring, however, and many unsolved problems on this subject still remain this is due, in part, to thelr complexity and to the many parameters that affect the ignition sensitivity and the explosibility of coal dust. Msha filled the tank at 5% methane with a teaspoon of coal dust to show how explosive it is. The explosion may have involved combustible dust, flammable gases. A dust explosion can be catastrophic and cause employee deaths, injuries, and destruction of entire buildings. A dust explosion is the rapid combustion of fine particles suspended in the air within an enclosed location.