— •. Reduction of volatile matters in coal dust intensified explosion severity while inhibited flame propagation of the mixtures. •. Qualitative analysis and quantitative …
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Coal Dust. In subject area: Materials Science. Coal dust explosion is a process of rapid oxidation reaction between oxygen in air and coal dust under the action of high …
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— Main Difference – Coal vs Charcoal. Coal and charcoal are carbon-containing compounds. Coal is a sedimentary rock.It is primarily composed of carbon along with trace amounts of some other elements such as hydrogen, sulfur, and nitrogen.Charcoal, on the other hand, is an impure form of carbon that is obtained by partial burning of …
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— The experimental system is shown in Fig. 1, which consists of a cylindrical chamber, a dust unit, an ignition unit, a laser schlieren unit, a high-speed camera, a data acquisition unit, and a synchronous control unit.The 60-L chamber is a horizontal cylinder with an internal diameter of 0.4 m and a length of 0.5 m with 0.14 m-diameter quartz …
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— Regarding the heterogeneous reactions of raw coal dust particles, the decreasing combustion reaction rate, and heat generation rate had a negative impact on the devolatilization and combustion of coal dust. Therefore, the combustion reactions and consumption of coal char, fixed carbon, and active structures were insufficient and …
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— The reaction front of CH 4 /coal dust mixture is captured by a high-speed camera equipped with an image intensifier and a bandwidth filter. The turbulence parameters of flow fields are recorded by Particle Image Velocimetry. ... Effect of fuel ratio of coal on the turbulent flame speed of ammonia/coal particle cloud co-combustion at …
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— Coal is the basic energy and important industrial raw material in China, and the energy system dominated by coal has supported the rapid development of the national economy (Chen et al., 2008; Wang et al., 2021).In the process of coal mining, because coal dust and gas often coexist in coal mines, when the gas is ignited and under the action of …
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In 2001, the ACGIH recommended 0.9 mg·m −3 as a respirable fraction in lignite coal dust and 0.4 mg·m −3 for anthracite coal dust. The UK in 2011 set the OELs for coal dust respirable fraction to 1.6 mg·m −3 with 0.4 mg·m −3 for anthracite and 0.9 mg·m −3 for bituminous dust over a time-weighted average of 8 h .
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— The concept of 'just transition' goes back to the 1990s. It was coined by trade unions to support social assistance programs for workers who lost their jobs as a result of environmental ...
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Geologists also classify coal types according to the organic debris, called macerals, from which the coal is formed. Macerals (microscopic organic constituents found in coal) are identified (microscopically) by reflected light - the reflective or translucent properties of the coal indicating the individual component macerals
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— The surface tension of the molasses solution reached 41.37 mN/m and the viscosity increased to 6.79 mPa·s; (4) molasses can significantly suppress the wind erosion of deposited coal dust, with its wind erosion mass decreasing 99.1%; finally, (5) the effectiveness of molasses at suppressing coal dust was discussed at a molecular level.
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— Catalytic coal gasification is a promising technology in the field of clean coal utilization. A comprehensive understanding of mechanisms, reaction kinetic, and reactor model is crucial. This article summarizes and analyzes the catalytic mechanisms of key reactions, such as C–O2, C–CO2, C–H2O, and CO–H2. It also compares various kinetic …
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— To mitigate environmental pollution caused by the escape of dust during coal storage and transportation, humic acid (HA) and grafted acrylamide (AM) were used as raw materials to prepare a composite dust suppressant suitable for coal storage and transportation. Single-factor experiments were used to explore the optimal synthesis …
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— At present, fossil fuel is used to meet 80% of the world's energy demands [1,2,3].Coal combustion accounts for over 27% of the energy output [2,4], resulting in the emissions of the oxides of sulfur (up to 55% of all the world's SO 2) and nitrogen (up to 25%), carbon dioxide (up to 45%) and fine ash particles (PM x) (up to 20%) [5,6].A high …
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— To this end, a review of coal dust combustion as reported in the literature is presented, and a mathematical model of flame propagation through coal dust-air mixtures is developed in detail. The model is basically used to predict burning velocities and to study the structure of coal dust-air flames.
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— In recent decades, the increasing demand and tremendous depletion of coal resources have resulted in numerous notorious thermodynamic disasters [1], [2], among which methane/coal dust explosion disasters are the most disastrous due to immeasurable property loss and countless casualties [3], [4], [5].Miserably, as presented in Fig. 1, the …
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— The sulfur, in coal, oxidizes upon combustion and pollutes the air, water, and land by releasing SOx (SO 2, SO 3, SO 3 2− and H 2 SO 4).The formation of the poisonous SO 2 gas, a major pollutant in air, may accelerate the rate of diseases and decrease life expectancy around power plants (Bascom et al., 1996, Kelsall et al., 1997, Health …
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— Autoignition and smoldering of coal dust have gained great safety concern in both industry and mining due to their high susceptibility to heating. To better understand their controlling mechanism, autoignition and smoldering of bituminous coal particles (1-mm diameter) and coal powders (0.1-mm diameter) in the form of bulk layer heated by 4–45 …
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— Thermodynamic analysis using the C-R method shows that the activation energy of the reaction between ASA and coal dust mixture is 91.371 % higher than the activation energy of the coal dust reaction during the rapid reaction phase, and the ASA makes the coal dust pyrolysis reaction require more energy and increase the difficulty of …
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— There are explosions in coal mines for other reasons, but coal dust explosions have contributed to the death of many miners. In modern coal mines, lawn sprinklers are used to spray water through the air in the mine and this reduces the coal dust in the air, and eliminates coal dust explosions.
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The production of coal dust is a common side effect of almost all mining activities (Shahan et al. 2019) Considering the global extent of coal mining and its potential for a large burden of ...
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— Instead, it might be a fraction for a fractal medium reaction. This is because coal combustion is so complex that it cannot be described as a basic reaction or a mixture of several basic reactions. Coal combustion is therefore influenced by many factors. 7.2.4.2.3 Restriction Effects of Surface Structure and Ash Layer
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The ignition temperature is generally lower for higher volatile matter content fuel. Because biomass particles have a higher volatile matter content than coal, they have a significantly lower ignition temperature, as Table 3.9 gives. Ignition temperature, however, is not necessarily a unique property of a fuel because it depends on several other factors like …
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— In order to achieve reliable application of coal in pulse detonation combustion chambers, this study explored the influence mechanism of equivalence ratio and coal type (lignite, anthracite) on the...
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— Despite international efforts to limit worker exposure to coal dust, it continues to impact the health of thousands of miners across Europe. Airborne coal dust has been studied to improve risk models and its control to protect workers. Particle size distribution analyses shows that using spraying systems to suppress airborne dusts can …
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— Among the reactions that have positive effects on NO generation, when ammonia-coupled coal char combustion occurred, only the R(14) reaction, i.e., oxidation …
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— Coal, a nonrenewable source of energy, has been an important component of the world's energy structure for a very long time. It can be seen from Fig. 1 (a) and (b) that since 1971, total worldwide coal production and coal consumption has grown by more than 150%. According to the International Energy Agency, the proportion of coal in primary …
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— A two–step parallel coal dust oxidation reaction mechanism is used to study the self–ignition and combustion characteristics of coal dust under inclination conditions. The consumption and transfer of multiple substances are considered. ... [13] was conducted in a static environment with an average wind speed of less than 0.01 m/s (measured ...
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However, different coal dust concentrations will lead to contrasting influence degrees on the result. Liu et al. [8] found that coal dust can accelerate the flame propagation speed of methane ...
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— A two–step parallel coal dust oxidation reaction mechanism is used to study the self–ignition and combustion characteristics of coal dust under inclination conditions. The consumption and ...
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— Notably, as C coal increases, the reaction that most affects methane consumption has evolved from R156 to R119 and finally to R38. Since the concentration and composition of the flammable gases (i.e., C c o a l) vary during spontaneous smoldering combustion of coal, the dominant elementary reaction in methane explosion …
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To investigate the flame propagation through hybrid mixture of coal dust and methane in a combustion chamber, a high-speed video camera with a microscopic lens and a Schlieren optical system...
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— Reactions of volatized methane are of secondary importance to the dynamics of the SFC. The SFC propagates at much faster speeds than can be explained by the local laminar flame speed of lifted coal dust. The high flame velocity was found to be caused by an autoignition wave of burning coal dust.
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