More than 70% of run-of-mine coal is enriched. At the same time, typical coal processing waste (slime, flotation waste, mid-coal and tailings) make up at least 10–15% of the raw coal mass. Approximately 220–300 million tons of coal processing waste is generated annually at coal-preparation plants in Russia and China.
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This article describes an experimental study on NOx emissions in pulverized coal combustion after preheating and air staging. The process takes place in two stages: the pulverized coal is first preheated in a circulating fluidized bed, and then the resulting fuel gas and char particles are burned in a down-fired combustor under air …
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The effluent from this CFB flows to a pulverized coal combustor downstream for deep combustion. This technology has been recently commissioned in a 75 t/h CFB boiler. ... Despite the tremendous industrial success, the combustion of wet coal slime is a complex process and inevitably reduces the boiler's thermal efficiency [12], …
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1. Introduction. The data of the 2021 Statistical Review of World Energy indicated that coal consumption accounts for about 27.2% of the world's total primary energy consumption and more than 40% of electricity is generated by coal [1].Coal slime as the by-product is produced during the coal washing process, which accounts for …
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Previous studies on the co-combustion of sludge and coal have not effectively utilized the characteristics of the combustion process to predict thermal behavior. Therefore, focusing on these combustion process characteristics is essential to understanding and predicting thermal behavior during the co-combustion of sludge and …
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This study reports an experimental investigation on the nitrogen oxide (NOx) emissions in pulverized fuel (coal and char) combustion through preheating with a circulating fluidized bed. The high-temperature preheated fuel particles obtained from the circulating fluidized bed would be burned in the down-fired combustor. The focus of this …
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Coal has been important energy to support China's economy for a long time. However, the process of coal washing produces a massive of coal slime, with strong water holding capacity, high ash content, low calorific value, and strong adhesion [].According to official statistics, the production of coal slime has reached 195 million …
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ABSTRACT Coal slime, coal slime/CaO, and coal slime/CaO/pine sawdust were formed to make briquettes respectively. The effects of pine sawdust on the SO2 retention by CaO during coal slime briquette combustion were studied using a tube furnace. The obtained results demonstrated that porous structures were created in the …
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In the process of raw coal washing, a large number of coal slime is generated. Coal slime is a very complex heterogeneous material composed of a large number of pulverized coal, colloid, organic debris, inorganic particles, bacteria, etc., with the characteristics of high moisture, high ash content, high viscosity and low calorific …
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Coal slime is a common byproduct during coal processing, and the output of coal slime increased sharply with the increase in coal demand, the continuous improvement of coal mining mechanization ...
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Circulating fluidized bed (CFB) boilers has realized the clean and efficient utilization of inferior coal like gangue and coal slime, high sulfur coal, anthracite, petroleum coke, oil shale and other resources. As a country with the largest amount of CFB boilers and the largest installed capacity in the world, China has 440 100–600 MWe CFB boilers …
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X-ray photoelectron spectroscopy (XPS, ESCALAB 250Xi, Thermo Fisher, Waltham, MA, USA) and X-ray diffraction (XRD, PANalytical Empyrean, PANalytical, …
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With the increasing amount of coal slime in the process of coal washing, it is of great significance to realize the clean utilization of coal slime for sustainability and environmental ... Characteristics of pulverized-coal combustion in the system of oxygen/recycled flue gas combustion. T. Kiga S. Takano +4 authors M. Kato. …
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coal substance, and only small quantities are held by the associated mineral matter. In contrast, inherent moisture depends on its humidity and thermal history, as well as on coal type. 2.2 Process of drying The process of drying includes the evaporation of surface moisture and, subsequently, the loss of inherent moisture.
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This numerical indicator combines the statistical characteristics of four flame parameters which are derived from the flame images. To evaluate the effectiveness of the proposed method, the numerical indicator of a pulverized coal flame during a routine unit "turning off" process was determined on a 600 MWth coal-fired supercritical unit.
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In this work, a novel vertical tandem-type drop-tube furnace system was set up, in which a temperature of as high as 1600 °C can be achieved. Experimental …
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DOI: 10.1016/J.JECE.2021.106249 Corpus ID: 238664876; Investigation on combustion, gaseous pollutants emission and ash characteristics during co-combustion of semicoke and coal slime
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Nitrogen oxides, being the second most toxic combustion product of pulverized coal fuel, turn to HNO 3 in the air and are the most common component of acid rains . ... (Kemerovo region, Russia) and coal slime was derived from the processing of coal of the same rank. Coal components were first ground in a rotor mill and riddled to …
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accumulation of a large amount of coal slime would cause soil pollution, and the air-dried coal slime also would cause dust in the air [3, 4]. At present, the usage of coal slime can be divided into the following three categories [5 –7]: (1) Co-combustion. Due to the high moisture content of coal slime, the co-combustion
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Co-pyrolysis of the coal blend with lignocellulosic biomass has a significant influence on final product composition of co-gasification and co-combustion. Successful evaluation of …
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The coal components were coking bituminous coal from the Berezovskoe deposit (Kemerovo region, Russia) and coal slime was derived from the processing of coal of the same rank. Coal components were first ground in a rotor mill and riddled to obtain a fine powder with a particle size of no more than 100 m. This pulverized …
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The obtained products include clean coal, gangue, pulverized coal, and coal slime, respectively. The coal slime consists of primary coal slime and secondary coal slime produced in the separation process, with the yields of 0.56% and 5.08% respectively. In the fine coal system, the total yield of coal slime is 5.64%.
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Recent developments in understanding pulverised coal combustion are reviewed. • The impact of important changes to coal-fire power generation are …
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Pulverized coal-fired units fire much or all of the lignite in suspension. Cyclone furnaces collect much of the ash as molten slag in the furnace itself. Stokers (other than spreader) retain a large fraction of the ash in the fuel bed and bottom ash. Spreader stokers fire about 15 percent of the coal in suspension and the remainder in a bed.
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Coal slime is a by-product of the process of coal preparation. Due to its special generation process, coal slime, whose particle sizes are less than 1 mm in general, is characterized by high water holding capacities, high ash and low heat values [7], [8]. Because of the above characteristics, coal slime is mostly abandoned directly or …
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1. Introduction. Flame stability in pulverized coal combustion is becoming increasingly an area of concern due to the trends of extending the use of low-quality coal and coal blends in existing power industries [1].An unstable flame can cause many combustion problems, such as furnace vibration, low combustion efficiency, high NOx …
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A combustion optimization method that incorporates neighborhood rough set machine learning that can help better account for the economy and pollutant discharge of the boiler combustion system during the variable working conditions, guide the operators to adjust the combustion more accurately, and effectively reduce the ineffective energy …
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The ever-increasing demand for steel and the subsequent depletion of high-grade ores requires the massive utilization of low-grade iron ores. In the present study, an iron ore slime sample containing 56.1% Fe was investigated using physical beneficiation, carbothermal reduction, and a microwave-assisted process; however, physical …
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Coal slime particles at different moments in the combustion process were removed to conduct N 2 adsorption, SEM and other tests and to analyze the structural …
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A new technique to preheat pulverized coal in a circulating fluidized bed was adopted. This technique consists of two stages: the pulverized coal is first self-preheated in a circulating fluidized bed, and then the preheated fuel gas and char particles are burned out in a down-fired combustor under air-staging conditions. Experiments were conducted …
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A 5% ratio is validated to be a reasonable cofiring ratio of coal slime in the actual operation without no slagging phenomenon. These results provide more insights …
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These wastes and by-products generally include weathered coal, mudstone, coal gangue and coal slime from coal mining and processing. Coal mining wastes mainly include weathered coal, which is produced from coal weathering in coal surface mining. Before mining, coal exists in a water-saturated, oxygen-free environment, any disturbance to …
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Pulverized coal ignition becomes possible when methane concentration exceeds 1.25 vol% [48]. The ignition of a mixture of methane, air, and coal dust includes two stages: methane ignition and coal dust ignition. ... Coal slime, which is a typical coal processing waste, can be a good candidate, provided that its low calorific value is ...
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