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James C. Hower - One of the best experts on this subject based on the ideXlab platform.
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Fundamental evaluation of petrographic effects on coal grindability by seasonal autoregressive integrated moving average (SARIMA)
International Journal of Mineral Processing, 2016Co-Authors: Saeid R. Dindarloo, James C. Hower, Amirhossein Bagherieh, Alan S. TrimbleAbstract:Abstract A series of coal Hardgrove grindability index (HGI) tests were performed to determine each iteration's content of the monomacerite Microlithotypes vitrite (Vt) and inertite (In), the bimacerite Microlithotypes clarite (Cl) and durite (Du), and the trimacerite Microlithotypes duroclarite (Dc) and clarodurite (Cd). In HGI tests, larger particles are broken in grinding, the resulting daughter particles can be composed of different Microlithotypes than the parent particle. Therefore, predicting the overall composition of the later iterations is complicated. A time series of the compositions values was constructed by sequencing the contents of all iteration (in different mesh sizes) by the order of iterations. Seasonal autoregressive integrated moving average (SARIMA), a widely used method of time series analysis, was employed for forecasting the final iteration's content of Vt, In, Cl, Du, Dc, and Cd. The proposed methodology was able to forecast the last iteration's composition, comparable to the actual observation.
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Notes on the relationship between microlithotype composition and Hardgrove grindability index for rank suites of Eastern Kentucky (Central Appalachian) coals
International Journal of Coal Geology, 2014Co-Authors: Antonia E. Hansen, James C. HowerAbstract:Abstract Hardgrove grindability index (HGI) has been a standard test in the coal and coal-fired power generation industries since the 1930s. Previous studies have demonstrated the relationship between HGI and coal rank and the maceral and mineral composition. In particular, within the high volatile bituminous rank range, HGI increases with an increase in coal rank and, for any specific rank, decreases with an increase in the liptinite content. Fundamentally, the HGI test is approximately at the scale of coal Microlithotypes, the microscopic assemblages of macerals. In this study, for two relatively narrow rank ranges, each spanning 0.05% Rmax, we examined the relationship between HGI and several maceral and microlithotype ratios for Pennsylvanian eastern Kentucky coals. While some relationships do show statistically significant trends, not all were as well defined as might have been expected.
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Notes on the methods of the combined maceral/microlithotype determination in coal
International Journal of Coal Geology, 2012Co-Authors: James C. Hower, Nicola J. WagnerAbstract:Abstract Both macerals and Microlithotypes, the microscopic assemblages of macerals, reveal basic information on coal depositional environments and coal utilization. The combined analysis of the full ICCP suite of macerals and Microlithotypes on oriented block samples provides a powerful synergistic technique in petrographic analysis. An example applying a combined maceral/microlithotype analysis of a Nova Scotia coal demonstrates the value of the technique in providing detailed information on the nature of the megascopically identifiable coal lithotypes.
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Maceral/ microlithotype partitioning with particle size of pulverized coal: Examples from power plants burning Central Appalachian and Illinois basin coals
International Journal of Coal Geology, 2007Co-Authors: James C. HowerAbstract:Pulverized coals from eleven power plants burning Central Appalachian coal blends and eight power plants burning Illinois Basin coal blends were studied in order to assess the petrographic nature of industrial-scale coal grinding. All coals were high volatile bituminous. Coals were wet screened at 100 (150 μ), 200 (75 μ), 325 (about 40 μ), and 500 (about 25 μ) mesh. Petrographic analysis of the whole coals and size fractions consisted of a combined maceral and microlithotype analysis. Microlithotype analysis, in particular, provides a reasonable approximation of the whole-particle composition at the scale of utility coal pulverization. In the size fractions, duroclarite, the most abundant trimaceral microlithotype, is most abundant in the coarsest fraction and least abundant in the finest fraction. Vitrite, the most abundant monomaceral microlithotype, exhibits the opposite trend. Duroclarite becomes more enriched in vitrinite towards the finer sizes. The partitioning of Microlithotypes and the partitioning of macerals within the Microlithotypes is indicative of the relative brittle nature of vitrite compared to the hard-to-grind trimaceral Microlithotypes. Increased vitrinite in duroclarite is an indication that the microlithotype within the particular size fraction is more brittle than relatively vitrinite-depleted duroclarite in coarser fractions. The relative grindability of Microlithotypes will, in turn, impact combustion efficiency.
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Studies of the relationship between coal petrology and grinding properties
International Journal of Coal Geology, 2003Co-Authors: Alan S. Trimble, James C. HowerAbstract:Abstract The maceral and microlithotype composition of selected coals has been investigated with respect to the grinding properties, specifically Hardgrove grindability index (HGI), of the coals. The study expands upon previous investigations of HGI and coal petrology by adding the dimension of the amount and composition of the Microlithotypes. Coal samples, both lithotypes and whole channels, were selected from restricted rank ranges based on vitrinite maximum reflectance: 0.75–0.80% R max , 0.85–0.90% R max and 0.95–1.00% R max . In this manner, the influence of petrographic composition can be isolated from the influence of rank. Previous investigations of high volatile bituminous coals demonstrated that, while rank is an important factor in coal grindability, the amount of liptinite and liptinite-rich Microlithotypes is a more influential factor. In this study, we provide further quantitative evidence for the influence of Microlithotypes on HGI and, ultimately, on pulverizer performance.
Grzegorz J. Nowak - One of the best experts on this subject based on the ideXlab platform.
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Facies studies of bituminous coals in Poland
International Journal of Coal Geology, 2004Co-Authors: Grzegorz J. NowakAbstract:Abstract Polish bituminous coal basins are associated exclusively with Carboniferous deposits, differing in origin and geological structure. This paper presents only short review of papers of Polish authors on coal facies studies of Carboniferous coals occurring in the Lower Silesian Coal Basin (LSCB), Upper Silesian Coal Basin (USCB) and Lublin Coal Basin (LCB) of Poland. Facies investigations of Carboniferous coals of Poland have been in progress over 20 years. The results of these studies have provided new information on such subjects as: (i) recognition of main depositional conditions in paleomires, (ii) determine prevailing paleoplant communities, (iii) appraisal of peat-forming environment reconstruction-types and characteristics of paleomires. These facies analyses are connected to results of such studies as: pure coal petrology, using maceral and microlithotype composition as parameters of the environment of coal deposition, combined results of petrological, palynological and sedimentological studies.
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Lithotype variation and petrography of coal seams from the żacler Formation (Westphalian) in the Intrasudetic Basin, southwestern Poland
Organic Geochemistry, 1993Co-Authors: Grzegorz J. NowakAbstract:Abstract Lithotype variations in the coal seams of the Westphalian zacler Formation were studied with reference to their maceral and microlithotype composition. District variability of lithotypes and petrography in particular seam sections have been observed. Generally, semibright coals predominate in the coal seams of the NW part of the Intrasudetic Basin (the Walbrzych area), whereas in the Nowa Ruda area (E part) the seams studied consist mostly of bright lithotypes. The variation in lithotypes is directly related to petrographic variation on the microscopic scale. The seams studied predominantly contain vitrite, vitrinertite- vitrite, and trimacerites in particular parts of the Intrasudetic Basin. Megascopic lithology and petrography of coals are the result of the different coal deposition environments.
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Lithotype variation and petrography of coal seams from the Zacler Formation (Westphalian) in the Intrasudetic Basin, southwestern Poland
Organic Geochemistry, 1993Co-Authors: Grzegorz J. NowakAbstract:Abstract Lithotype variations in the coal seams of the Westphalian zacler Formation were studied with reference to their maceral and microlithotype composition. District variability of lithotypes and petrography in particular seam sections have been observed. Generally, semibright coals predominate in the coal seams of the NW part of the Intrasudetic Basin (the Walbrzych area), whereas in the Nowa Ruda area (E part) the seams studied consist mostly of bright lithotypes. The variation in lithotypes is directly related to petrographic variation on the microscopic scale. The seams studied predominantly contain vitrite, vitrinertite- vitrite, and trimacerites in particular parts of the Intrasudetic Basin. Megascopic lithology and petrography of coals are the result of the different coal deposition environments.
William M. Andrews - One of the best experts on this subject based on the ideXlab platform.
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Maceral and microlithotype response to oil agglomeration for selected eastern Kentucky high volatile A bituminous coals
Fuel Processing Technology, 1997Co-Authors: James C. Hower, Kenneth W Kuehn, B K Parekh, William M. AndrewsAbstract:Abstract The petrographic response of three high volatile A bituminous, petrographically complex eastern Kentucky coals to oil agglomeration was tested using several agglomerating oils. Four oils, hexane, fuel oil, kerosene, and pentane, were tested on the Leatherwood coal, the intermediate coal in the rank series. The testing scheme for the other two coals consisted of using only the hexane and fuel oil with a lesser number of tests than on the initial coal tested. Coal rank emerges as a significant parameter in the behavior of the coals. Particularly for the hexane agglomeration, the coals had quite different behaviors, with the highest-rank coal having greater clean-coal yield at lower oil concentrations than the other two coals. The two high-rank coals exhibit similar yield curves for fuel oil, with the lower-rank coal achieving the yield of the latter coals at higher oil concentrations. The role of the organic petrography and the mineral matter, both closely associated with the macerals in carbominerite Microlithotypes and organic-dominant Microlithotypes, is an obvious complicating factor. A tendency for duroclarite, the vitrinite-rich trimaceral microlithotype, to partition between vitrinite-rich varieties in the concentrate and vitrinite-poor varieties in the tails was noted at higher oil concentrations for all three coals.
B K Parekh - One of the best experts on this subject based on the ideXlab platform.
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maceral and microlithotype beneficiation in column flotation at the powell mountain coal mayflower preparation plant lee county virginia
Fuel Processing Technology, 2000Co-Authors: James C. Hower, Kenneth W Kuehn, B K Parekh, William J PetersAbstract:Maceral and microlithotype partitioning among several coals processed through a column flotation system installed at Powell Mountain Coal Mayflower Plant in Virginia was examined. Column flotation produces a product enriched in vitrinite and the vitrinite-rich varieties of individual Microlithotypes were compared to the feed coal. Similar trends were observed for several Eastern Kentucky froth flotation installations. Rank variation among the coals, while subtle, was sufficient to preclude holding rank as a constant in comparisons between the coals.
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Maceral and microlithotype response to oil agglomeration for selected eastern Kentucky high volatile A bituminous coals
Fuel Processing Technology, 1997Co-Authors: James C. Hower, Kenneth W Kuehn, B K Parekh, William M. AndrewsAbstract:Abstract The petrographic response of three high volatile A bituminous, petrographically complex eastern Kentucky coals to oil agglomeration was tested using several agglomerating oils. Four oils, hexane, fuel oil, kerosene, and pentane, were tested on the Leatherwood coal, the intermediate coal in the rank series. The testing scheme for the other two coals consisted of using only the hexane and fuel oil with a lesser number of tests than on the initial coal tested. Coal rank emerges as a significant parameter in the behavior of the coals. Particularly for the hexane agglomeration, the coals had quite different behaviors, with the highest-rank coal having greater clean-coal yield at lower oil concentrations than the other two coals. The two high-rank coals exhibit similar yield curves for fuel oil, with the lower-rank coal achieving the yield of the latter coals at higher oil concentrations. The role of the organic petrography and the mineral matter, both closely associated with the macerals in carbominerite Microlithotypes and organic-dominant Microlithotypes, is an obvious complicating factor. A tendency for duroclarite, the vitrinite-rich trimaceral microlithotype, to partition between vitrinite-rich varieties in the concentrate and vitrinite-poor varieties in the tails was noted at higher oil concentrations for all three coals.
Kenneth W Kuehn - One of the best experts on this subject based on the ideXlab platform.
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maceral and microlithotype beneficiation in column flotation at the powell mountain coal mayflower preparation plant lee county virginia
Fuel Processing Technology, 2000Co-Authors: James C. Hower, Kenneth W Kuehn, B K Parekh, William J PetersAbstract:Maceral and microlithotype partitioning among several coals processed through a column flotation system installed at Powell Mountain Coal Mayflower Plant in Virginia was examined. Column flotation produces a product enriched in vitrinite and the vitrinite-rich varieties of individual Microlithotypes were compared to the feed coal. Similar trends were observed for several Eastern Kentucky froth flotation installations. Rank variation among the coals, while subtle, was sufficient to preclude holding rank as a constant in comparisons between the coals.
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Maceral and microlithotype response to oil agglomeration for selected eastern Kentucky high volatile A bituminous coals
Fuel Processing Technology, 1997Co-Authors: James C. Hower, Kenneth W Kuehn, B K Parekh, William M. AndrewsAbstract:Abstract The petrographic response of three high volatile A bituminous, petrographically complex eastern Kentucky coals to oil agglomeration was tested using several agglomerating oils. Four oils, hexane, fuel oil, kerosene, and pentane, were tested on the Leatherwood coal, the intermediate coal in the rank series. The testing scheme for the other two coals consisted of using only the hexane and fuel oil with a lesser number of tests than on the initial coal tested. Coal rank emerges as a significant parameter in the behavior of the coals. Particularly for the hexane agglomeration, the coals had quite different behaviors, with the highest-rank coal having greater clean-coal yield at lower oil concentrations than the other two coals. The two high-rank coals exhibit similar yield curves for fuel oil, with the lower-rank coal achieving the yield of the latter coals at higher oil concentrations. The role of the organic petrography and the mineral matter, both closely associated with the macerals in carbominerite Microlithotypes and organic-dominant Microlithotypes, is an obvious complicating factor. A tendency for duroclarite, the vitrinite-rich trimaceral microlithotype, to partition between vitrinite-rich varieties in the concentrate and vitrinite-poor varieties in the tails was noted at higher oil concentrations for all three coals.