The realtime quantitative analysis of the calorific value of pulverized coal particle flow is important for the efficient and clean combustion of coal. Herein, a piezoelectric vibratory feeder produced a continuous flow of pulverized coal particles, which were detected by laserinduced breakdown spectroscop
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The basis low calorific value received by raw coal, MJ/kg. 1. Introduction. ... Hightemperature DTF can quantitatively obtain the change in conversion proportion of in the combustion process of pulverized coal. However, the simulated atmosphere in a DTF is not representative of the complex gas environment in the furnace caused by the rotating ...
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The pulverized coal was dried at three selected temperatures of 25 °C, 75 °C and 110 °C, and the moisture and porosity of the pulverized coal particles were measured. Based on the porosity range obtained from the measurement, 3D steady numerical simulation of combustion in tangentially coalfired furnace was conducted by use of Fluent Software.
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The new equation is at least as effective in predicting calorific values for a set of 1004 coals as equiv. equations derived for 6 subsets of the coals. On the whole, the distributions of differences between obsd. and calcd. calorific values are skewed to only a small extent. About 86% of the differences lie between 300 and +300 Btulb.1.
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Heating value and vitrinite reflectance are both rank parameters (section ); although, as noted in section, calorific value is related to the maceral content as well as the coal rank. Grindability and particle size are also related ( section ), with particle size being a function of the grindability of the coal and the energy ...
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The biomass and coal samples were dried (according to ASTM D3302) and pulverized to obtain a size of less than 250 μm for characteristics tests such as proximate, ultimate, calorific value, and total chlorine. For the DTF combustion experiment and thermogravimetric analysis, the coal was pulverized to a particle diameter smaller than 75 μm.
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Two coals, bituminous (American Baily Pittsburgh No. 6) used in Israeli utilities and lignite (brown coal Hambach) used in German power plants, have been investigated in this study. The results show that the combined TG/DSC method can provide a much better understanding of the chemical reactivity of coals in the combustion process.
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Pulverized coal absorbs part of the heat to increase its own internal energy, enhancing the char performance and accelerating the achievement of the volatile matter combustion temperature; furthermore, the calorific value needed to reach the ignition temperature is guaranteed. 51 In the pyrolysis stage, WOS has a dominant effect on pulverized ...
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When there was no condition to test the coal calorific value in the industry, the net calorific value of coal could be calculated according to the empirical formula [30]. By contrasting the net calorific values of coal obtained by experience formula and experiment, LIU and JU [31] found that the deviation was less than 5%. It was shown
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Introduction. In 2014, the share of electricity produced in the world from coal combustion was % [1]. While this share will need to be drastically reduced in the coming decades to reach the current CO 2 emission targets, it is nonetheless important to keep on increasing the efficiency of the existing assets worldwide in order to limit their global environmental impact.
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In this paper, a calorific value detection method based on NIRSXRF fusion spectroscopy is proposed, which utilizes NIRS to detect organic functional groups and XRF to detect inorganic ashforming elements in coal.
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To reduce the cost of electricity production, lowquality coal with low calorific value is used and mixed with various types of coal in Korea. Coal is roughly composed of 69% carbon, 15% oxygen, % coal ash, 5% hydrogen, % nitrogen, % sulfur, and % other components.
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Though several factors affect the calorific value, including the type of coal, particle size, and environmental conditions [2530]. The scope of this work is limited to explore the effect of environmental factors (temperature, humidity, and air flow) on low grade coal pulverized to obtain average particle size of 213 μm, according to ...
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To explore methods of reducing NOx emission from pulverized coal boilers, the effects of injecting ammonia solution and pyrolysis gas into the furnace on NOx emission were experimentally investigated on a 75 t/h pulverized coal boiler. Results show that the deep air staging with 30% separated over fire air (SOFA) creates a high temperature and strong reducing atmosphere in the reducing zone ...
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The interaction between the optical thickness and the radiation pulsation of pulverized coal particles during the combustion process is studied to learn the influences of turbulent particle combustion on radiative heat transfer.
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However, in traditional oxyfuel combustion systems, the ASU and CO 2 compression and purification unit (CPU) are carried out at high pressure, but the fuel combustion unit (pulverized coal boiler or fluidized bed boiler) is operated at atmospheric pressure, the unbalanced distribution of system pressure results in a large amount of energy loss ...
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error (ARE), and the standard deviation (SD) of this method for predicting the calori c value of coal are fi MJ kg−1, % and MJ kg−1 respectively. The measurement repeatability...
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Other articles where pulverizedcoal combustion is discussed: coal utilization: Pulverized coal: Pulverizedcoal combustion is widely used in large power stations because it offers flexible control. In this method, coal is finely ground so that 70 to 80 percent by weight passes through a 200mesh screen. The powder is burned in a combustion chamber by.
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Fig. 4 shows the volume fractions of these gases mentioned above and the net calorific value (CV, MJ/Nm 3) of the preheated coal gas. The calorific value of CO is higher than those of CH 4 and H 2, and more CO is generated in O 2 /CO 2. Therefore, the net calorific value of the preheated coal gas in O 2 /CO 2 is higher than that in air. In air ...
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The Chinese national standard GB/T [7] exhibits the experimental specification for coal calorific measurement using the bomb X. Zhang et al. Laserinduced breakdown spectroscopy (LIBS ...
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The Chinese national standard GB/T [7] exhibits the experimental specification for coal calorific measurement using the bomb calorimeter. However, the bomb calorimeter has a complex structure, cumbersome operation, and has a large measurement hysteresis, which makes it impossible to obtain the realtime calorific value of coal.
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A pulverized coalfired boiler is an industrial or utility boiler that generates thermal energy by burning pulverized coal (also known as powdered coal or coal dust since it is as fine as face powder in cosmetic makeup) that is blown into the firebox.. The basic idea of a firing system using pulverised fuel is to use the whole volume of the furnace for the combustion of solid fuels.
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It uses coke and auxiliary injectants like pulverized coal (PC) to generate the reductants and energy needed. However, coke production causes considerable energy consumption and greenhouse emissions and accounts for a big portion of pig iron production costs [1]. Also, coking coal resource is gradually depleted on the earth.
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The given values are for fuels with the given density. The variation in quality may give heating values within a range 5 10% higher and lower than the given value. Also the solid fuels will have a similar quality variation for the different classes of fuel. 1 Btu (IT)/lb = MJ/t = J/kg = kcal/kg = kWh/kg.
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A hyphenated model was proposed to improve the accuracy of calorific value. ANN and GA were employed for identifying the calorific value in 86 coal samples, and the AAE was MJ/kg [95]. The SVR method based on KCV was proposed for quantitative analysis of 44 coal samples, and the MSE of calorific value was (MJ/kg) 2 [78].
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The tests performed show that the values of min. ignition temps. and the ignition delay times for the analyzed coals depend to a large extent on the coal rank. The ignition temp. and ignition time decreased when the volatile matter content in the coal increased and the calorific value of the fuel decreased, when the rank of coal decreased.
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Densephase pneumatic conveying of pulverized coal experiments with superficial gas velocity ranged from m s −1 to m s −1 were carried out on the selfestablished 50 mm industrial pipe facility. The fluctuations of pressure, solid velocity, solid concentration and the average crosssection concentration were analyzed in terms of relative standard deviation (RSD), powder ...
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34 Gudimella Tirumala Srinivas et al.: Efficiency of a Coal Fired Boiler in a Typical Thermal Power Plant s [( ) ( )]2 1 4 3 100 f f w h h h h w GCV × − + − = × × (3) Here GCV f is the gross calorific value of the coal (kJ/kg), whose measurement is based on mass of coal for which hoppers are mounted over the boilers on calibrated load cells [15].
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The coal consumption in our country mainly lies in coalfired power stations and industrial boilers. 1 Since the temperature change in the furnace influences combustion, slagging, corrosion, and so on, 2 the accurate analysis of the temperature level and its distribution in the furnace will predict the slagging in the furnace and improve the saf...
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Considering an injection rate of 100 kg/t of pig iron, when a coal with a calorific value of 7500 kcal/kg is replaced by another one with 7700 kcal/kg, the fuel rate change is 4 kg/t of pig iron ...
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There has been little research on volatile releasing characteristics of pulverized coals under moderate or intense lowoxygen dilution (MILD) oxycombustion (MO) conditions. For the first time, volatile releasing characteristics of bituminous coal and semianthracite under both MILD aircombustion (MA) and MO conditions were investigated using a flatflame assisted entrained flow reactor. Both ...
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Lowrank coal (calorific value below 5,100 kcal/kg) and mediumrank coal (5,1006,100 kcal/kg) dominate current Indonesian coal production. Coal reserves are estimated to be about % for lowrank coal and around % for mediumrank coal. The country's power plants use both types of coal as fuel. Basically, coal calorific value is one ...
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The adiabatic bomb calorimeter and the isothermal bomb calorimeter are two standard methodologies defined by GB/T [3], ISO 1928 2009 (E) [4] and ASTM D586513 [5]. In bomb calorimetry, coal burns in a bomb, and the heat of combustion is transferred to water outside the bomb wall.
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recovered fuel (SRF). RDF had only two classes depending only on the calorific value, moisture and ash content, in contrast to 125 SRF classes. These SRF classes are based on three properties where each of the properties has five classes for the net calorific value, the chlorine content, and the mercury content [8].
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The detailed procedure used to conform both the calorific value and elemental component balance of a coal particle in the numerical simulation to the calorific value obtained by both proximate analysis and ultimate analysis is available in the relevant literatures: Hashimoto N. et al. (2012a, 2012b), and Hashimoto N. and Shirai H. (2014).
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A material supplier from Belgium would like to produce limestone powder for his custome...
India is rich in various mineral resources and it is an important mineral processing market
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