Grindability index of coal is an important technological parameter to understand the behaviour and assess the relative hardness of coals of varying ranks and grades during comminution. This is usually determined by Hardgrove Grindability Index (HGI), which involves requirement of a costly grinding equipment and accessories not …
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Subtract the tare mass to obtain the mass of the + 75- µm ( + No. 200) material. Weigh the catch pan and its contents. Subtract the tare mass to obtain the mass of the − 75-µm (−No. 200) material. If the sum of these weights differs by more than 0.50 g from the initial weight of 50 6 0.01 g, reject the test and repeat.
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The spatial arrangement and abundance of the elements: C, H, N, O, S often correlate or directly influence a plethora of coal properties. For > 90 years, attempts have utilized the ultimate (elemental) analysis of coal to predict a wide variety of properties such as: calorific value (higher heating value), volatile matter, vitrinite reflectance (mean maximum), …
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Repeat the sieving for two more periods of shaking, each of 5 minutes, cleaning the. underside of the 75-micron sieve after each repetition. 8. IS : 4433 - 1979. 7.5 Weigh separately to the nearest 0.01 g of the coal retained on the. 75-micron sieve and the coal passing the 75-micron sieve. If the sum of.
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This paper presents results of investigations of torrefied biomass grindability using a modified Hardgrove test, with the volumetric sample approach and with the test sample wider particle size range of 0.2-1.18 mm. The HGI sample standard particle size range of 0.6-1.18 mm can be insufficient for biomass samples due to the inhomogeneous ...
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The Hardgrove method of specification of grindability is used mostly for determination of grindability of coal, but also in determining grindability of other raw materials. Bond's method is especially used for determining rock grindability. On the basis of the results of Bond's results of determination we can to advantage empirically ...
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Steel balls within the unit crush the coal sample; The coal fines are sorted and the quantity of coal less than a specified size is recorded and converted into a Hardgrove Grindability Index (HGI) value; Typical resulting HGI values lie between 30 (increased resistance to pulverization) and 100 (more easily pulverized).
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7. Preparation of Test Samples. 7.1 Prepare a 1.18-mm 3 600-μm (No. 16 3 No. 30) test sample for establishing the HGI of SRSs, for calibration, or for routine determination of HGI. 7.2 When necessary, divide the quantity of 4.75-mm (No. 4) sieve size coal to not less than 1000-g lots using an enclosed.
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Coal rank, plotted as vitrinite maximum reflectance, vs. Hardgrove grindability index for 820 coals with ≤20% ash (dry basis) from the Penn State University coal database. From Hower et al ...
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Hardgrove grindability index (HGI) is a common procedure in coal analysis. The test fraction does not correspond to the whole coal, leading to a petrographic and …
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The Hardgrove grindability index is used empirically to estimate the capacity and power consumption of a pulverizer, given a specified product fineness. 1 Scope This …
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behavior of coal for size reduction, it is necessary to use the tests based on size reduction. One of usual methods for determining the grindability of coal is Hardgrove index method. Soft or hard coals were evaluated for the grindability - toward 100. Coal HGI depends on the coalification, moisture, volatile
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ISO 5074:2015 specifies the method for determining the grindability index of hard coal using the Hardgrove machine. It also specifies the procedure for calibrating the test machine and for preparing the standard reference coal samples. NOTE In this International Standard, the term "hard coal" is used as an indication of maturity or rank in the ...
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Dec 31, 1996· A general prediction model for the Hardgrove grindability index was constructed from 735 coal samples using the proximate analysis, heating value, and sulfur content. The coals used to develop the general model ranged in volatile matter from 12.8 to 49.2 percent, dry basis, and had grindability indexes ranging from 35 …
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Correspondingly, the Hardgrove grindability decreases with increase in the volatile matter and decrease in the vitrinite reflection coefficient due to increase in the …
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determining hardgrove grindability index of coal samples. Each sample was crushed and screened to obtain a fraction of sample having size less than 4.75 mm which was subsequently ground and screened
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1. Introduction. While the Hardgrove grindability index (HGI) is a long-established test for the evaluation of coals for combustion and, compared to many of the chemical tests of coal, the equipment is cheap and relatively easy to maintain, the test is inherently inaccurate owing to the simple fact that the test fraction is generally not …
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the tested coal sample with the change in the surface of the standard coal. In the Hardgrove method, the reference material is coal from the Kittanning deposit of the St. Jerome mine (Somerset, PA, USA), for which the Hardgrove grindability index is equal to 100. Figure1shows a diagram of the Hardgrove index measuring device built in 1932 by
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Physics. Coal. Article PDF Available. Hardgrove Grindability of Coal. Part 1. Correlations with Composition, Structure, and Properties. January 2019. Coke and …
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The Hardgrove grindability index (HGI)13,14 and Bond work index (BWI)15,16 are two well-known methods used to evaluate the grindability of coal. Reportedly, HGI and BWI are closely correlated in some biomass samples.17 HGI, the most common index for grindability, is widely used as the accepted Received: June 3, 2020 Accepted: August …
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Division Name: Petroleum, Coal, and Related Products Section Name: Solid Mineral Fuels (PCD 7) Designator of Legally Binding Document: IS 4433 Title of Legally Binding Document: Method for Determination of Hardgrove Grindability Index of Coal Number of Amendments: Equivalence: Superceding: Superceded by: LEGALLY …
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The Hardgrove grindability index HGI is closely related to the power consumed in crushing coal and may be used to optimize crushing in the coal-preparation shops at coke plants, as shown in [1–7].The factors affecting HGI for Ukrainian and imported coal were studied in [].The results showed that HGI depends on the carbon content and …
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This work evaluates, analyzes, and predicts the grindability and abrasive behavior of coal blends. Three binary coal blends with common low-grade coal were first prepared at various ratios. Blends ...
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particle size distribution of the pulverized fuel among other factors. For coal, the Hardgrove Grindability Index (HGI) test was developed to characterize the relative grindability of a particular quality of coal relative to a pre-determined standard quality of coal (ASTM D409). The HGI test is an empirical batch
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ISO 5074:2015 specifies the method for determining the grindability index of hard coal using the Hardgrove machine. It also specifies the procedure for calibrating the test …
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HGI of coal and its hardness characteristics. In order to determine the comminution behaviour of coal, it is necessary to use tests based on size reduction. One of common methods for determining the grindability of coal is the HGI method. Soft or hard coals were evaluated for the grindability - toward 100. A coal's HGI depends on the ...
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Introduction. While the Hardgrove grindability index (HGI) is a long-established test for the evaluation of coals for combustion and, compared to many of the chemical tests of coal, the equipment is cheap and relatively easy to maintain, the test is inherently inaccurate owing to the simple fact that the test fraction is generally not …
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Coal grindability can be evaluated using a grinding machine, in accordance with certain procedures described in technical standards, in order to obtain the designated Hardgrove Grindability Index ...
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Predictions of the Hardgrove grindability index, a predictor of the crushing and pulverization propensity of coal, have been made using both regression and neural network techniques. All techniques suffer from shortcomings. In general, input parameters must be selected based on a sound knowledge of coal chemistry and petrology, with avoidance ...
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The relationship between Hardgrove grindability and coal microlithotype composition was studied for three coals from two eastern Kentucky mines. The purpose of the study was to further investigate the use of petrographic data as a predictor of mechanical properties important in mining and utilization. Samples were collected according to ...
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The grindability index is determined by comparing the results of a sieve analysis of the ground sample with a calibration graph plotted using standard reference material. 4 Apparatus. The following equipment shall be used. a)Balance, capable of weighing up to 100 g to an accuracy of 0,01 g. b)Balance, capable of weighing up to 1500 g to an ...
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The correlations of the composition, structure, and properties of coal from Ukraine, Russia, Canada, Australia, the Czech Republic, Poland, and Indonesia with its Hardgrove grindability index are investigated. It is found that the Hardgrove grindability increases with increase in total carbon content Cdaf and aromatic carbon content Car, as …
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This paper presents the results of a study on the influence of selected parameters of coal on the Hardgrove Grindability Index (HGI). The samples used in the investigation came from the same Polish coking-coal mine. The samples varied in terms of their quality parameters, i.e., volatile matter, ash content, chemical composition, maceral ...
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Combustion behavior of rice straw torrefied at 300 °C for different residence time and their blends with sub-bituminous coal was investigated. The torrefied product and its blends were characterized for fuel properties and Hardgrove Grindability Index (HGI). Also, the torrefied product is characterized fordensity, proximate and ultimate analysis, …
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D409 Test Method for Grindability of Coal by the Hardgrove-Machine Method D4930 Test Method for Dust Control Material on Calcined Petroleum Coke 3. Terminology 3.1 Definitions: 3.1.1 calcined petroleum coke, n - petroleum coke that has been thermally treated to drive off the volatile matter and to develop crystalline structure.
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Coal B, used in Test 1, has a relative grind ability of 100, coal P, in Test 5, has a relative grindability of 45, and coal M, in Test 6, has a relative grindability of 120. With the same charge of pebbles in the mill in each case, coal B was ground for 5 min and coals M and P for 20 min each.
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Abstract. Grindability index of coal is an important technological parameter to understand the behaviour and assess the relative hardness of coals of varying ranks …
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An improved predictor of coal pulverization behavior and coal feed rate is under development at the CAER based upon the interaction between Hardgrove Grindability Index (HGI) and coal petrology. With educated attention, this interaction may be a useful tool to enhance coal feed rates if cautiously extended to the mining environment where …
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