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1.
The demand for metallurgical coke for blast furnaces is forcing the coking industry to look for new sources of coking coals. The physical and chemical parameters of coals used in coking blends determine the quality (reactivity and strength) of the finished cokes. This study examines the technical properties of the cokes produced from various blends of three Polish coals with different coking. These coals were collected from three mines: Zofiówka, Szczygłowice, and Krupiński (Upper Silesian Coal Basin, Poland). The coal charges were coked in the laboratory scale, at temperatures of up to 1000 °C, in an inert atmosphere. The coke reactivity (index CRI) and the coke strength after reaction (CSR) were measured and correlated to the properties of parent coals using statistical analysis. The result of this study shows strong relationships between the concentration of the best coking coal (Zofiówka) in the blend and the CRI and CSR of the resulting coke. The CRI and CSR parameters for cokes obtained from single coals and from their blends show the additive character. This study also confirms the linear relationship between CRI and CSR parameters of the cokes.  相似文献   

2.
Pilot-scale and plant cokes with initially different properties were subjected to weight loss by reaction with carbon dioxide, and the resulting products were characterized both microscopically and by ASTM Tumbler tests. The cokes were found to lose strength progressively as weight loss occured, and the examination of carbon forms and microstructures showed the strength changes to be related to the initial properties of the cokes and ultimately to particular compositional characteristics of the coals used to make the cokes. The results have been providing coal-selection guidelines to assist in the manufacture of higher-quality coke. Our coke reactivity test is also being used to signal changes in the coal supply and to monitor certain other coking parameters.  相似文献   

3.
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4.
The Liddell Seam occurs in the lower part of the Permian Foybrook Formation of the Sydney Basin, eastern Australia. The seam profile is dominated by banded lithotypes (clarain). Maceral and microlithotype analyses of lithotypes indicate a limited degree of uniformity in their composition. A comparison of whole-seam petrographic analyses with compositions calculated on the basis of the seam lithotype profile and lithotype petrography suggests that the latter method may provide for a rapid assessment of petrographic variation in operating mines.Petrographic analyses form the basis of an interpretation of Liddell peat-swamp facies. The seam contains few clastic layers which are associated with relatively dull coals whose petrography reflects elevated water levels during deposition in the limno-telmatic, reed-moor and open-moor facies. Between these zones the seam profile is dominated by relatively bright coals deposited between periods of inundation, in the telmatic forest-moor and reed-moor zones. The lithotype profile and the high vitrite and clarite content indicate the significant influence of arborescent vegetation, a feature typical of seams deposited in tectonically unstable areas.  相似文献   

5.
Curragh Queensland Mining Limited, Australia, produces a high quality medium volatile bituminous coking coal from the Orion, Pollux and Castor seams from the upper Permian Rangal Coal Measures. It is one of the lowest ash, prime hard coking coal blends produced in Australia. It is also low in sulfur and produces very strong coke when carbonized alone and in blends. Early attempts to predict coking properties of the coals from petrographic data produced predicted coke stabilities that were significantly lower than those determined from coke tests. There is some question as to how much of the ‘inertinite’ in these and other southern hemisphere coals is truly inert during carbonization and how much is reactive. The current study characterized the Curragh coals in terms of physical, chemical and petrographic characteristics and also involved the production of test oven cokes for characterization and strength testing. As part of the work effort a series of suggested techniques for improving predictions of coke strength from petrographic data were examined and a new and improved technique was developed for the Curragh coals. How broadly the technique can be applied to other coals needs to be determined.  相似文献   

6.
Palaeobotanical studies of the brown coal deposits of the Latrobe Valley have contributed significantly towards an understanding of the age of the deposits, existing climatic conditions and detailed depositional environments. This paper re-assesses some past reconstructions for the Early to Mid Miocene coals using recent information on plant distributions and their bioclimatic significance and on a marine incursion model for coal lithotype formation.The brown coal flora is composed overwhelmingly of rainforest taxa that presently cover a range of different environments within the Australasian region. The application of a bioclimatic prediction model to these taxa allows the construction of consistent and quantitative estimates of climates during coal-forming phases. It is considered that rainfall in the area was more than twice the 850 mm received today, with significant seasonal variation. The mean annual temperature estimate of about 19°C, indicating a mesothermal or subtropical environment, is some 2–5C higher than present and higher than previous estimates. It does, however, correspond with sea-surface temperature estimates for the Southern Ocean at this time.The original model of lithotype formation, which suggests that lithotypes conform to a successional sequence from open water in the lightest coloured lithotypes to raised bog in the darkest lithotypes, is considered to be inconsistent with the evidence for lightening upwards sequences within the coals, a central feature of the proposed marine incursion model of coal formation. The two models are reconciled to some degree by a reinterpretation of the palaeobotanical data and by the postulation of climatic rather than autogenic successional control over lithotype formation.  相似文献   

7.
The chemical properties of two high-volatile bituminous coals, the Danville Coal Member of the Dugger Formation and the Lower Block Coal Member of the Brazil Formation from southern Indiana, were compared to understand the differences in their coking behavior. It was determined that of the two, the Lower Block has better characteristics for coking. Observed factors that contribute to the differences in the coking behavior of the coals include carbon content, organic sulfur content, and oxygen/carbon (O/C) ratios. The Lower Block coal has greater carbon content than the Danville coal, leading to a lower O/C ratio, which is more favorable for coking. Organic sulfur content is higher in the Lower Block coal, and a strong correlation was found between organic sulfur and plasticity. The majority of the data for both seams plot in the Type III zone on a van Krevelen diagram, and several samples from the Lower Block coal plot into the Type II zone, suggesting a perhydrous character for those samples. This divergence in properties between the Lower Block and Danville coals may account for the superior coking behavior of the Lower Block coal.  相似文献   

8.
Degradation of coke in the blast furnace is influenced by its inherent mineral matter, the formation of which is itself dependent upon the nature of the coal mineral matter. To date few studies have been made of coke mineralogy and its relationship to the mineralogy of the parent coal. In this study the effect of carbonisation on coal mineral matter has been investigated by a detailed quantitative mineralogical examination of nine cokes and their parent coals. The quantitative analysis was performed on X-ray diffraction patterns of the mineral matter of cokes and coals, using SIROQUANT™. Coke mineralogy and its composition varied strongly between cokes, more strongly than variations in elemental composition of the ash. The mineral matter in the studied cokes consisted of crystalline mineral phases and also significant levels of amorphous phase (ranging between 44 and 75%). Decomposition of clays such as kaolinite, montmorillonite, illite and chamosite produced the amorphous phase and some of the crystalline mineral phases such as mullite, γ-alumina, spinel, cristobalite and leucite. The type of association of mineral matter in coals had an important role in how the clays decomposed. For example, association of kaolinite with silica-bearing minerals in intimate intermixture favoured formation of mullite over γ-alumina. Akermanite and diopside result from reaction of kaolinite with associated calcium bearing minerals (calcite, dolomite or ankerite). Quartz, fluorapatite and the three polymorphs of TiO2 (anatase, brookite and rutile) were the coal minerals that were least affected during carbonisation, as they were also found in the cokes, yet even they were affected in some cases.  相似文献   

9.
Although petrographic analysis of the lithotypes present in coal samples has been successfully used in the correlation of coal seams, the study of the environments of coal seam deposition, and the evaluation of the mining and cleaning properties of numerous coal seams, coal lithotype analysis is not routinely performed in North America at this time because it is very time consuming and requires the services of a highly skilled petrographer. The objective of this study was to evaluate the capability of one of the newly improved image analysis microscope systems to characterize coal lithotypes and perform automated lithotype analyses on polished block samples of coal.The results of this study show that each of the lithotypes examined, vitrain, clarain, fusain, and durain, yield a characteristic reflectance histogram and that analysis of reflectance histograms taken from a transverse, perpendicular to bedding, down a polished block sample yield results on the kinds and thicknesses of the lithotypes present that are in good agreement with the results obtained by manual methods.  相似文献   

10.
The River Gem coal bed (upper Westphalian A) was sampled at five sites in a single mine in Whitley County, Kentucky. Previous petrographic and sulfur analyses of the collected interval samples showed that the coal bed could be divided into a basal low-sulfur lithotype, a middle high-sulfur bone lithotype and an upper high-sulfur lithotype. At one location a high-sulfur rider unit is present. In this study we have conducted detailed palynological analyses on all of the interval samples and ash geochemistry on the upper high-sulfur lithotype intervals and two of the basal high-sulfur basal lithotype intervals.Geochemical analyses show that As and Pb are generally high in the high-sulfur upper lithotypes from all five sites. Carbonates, having associated high levels of Ba and Sr, are important in the ash geochemistry of the lower, low-sulfur lithotypes. Ga, Ge and W are enriched in the higher vitrinite lithotypes among the low-sulfur samples. The basal lithotype at each of two sites, which was analyzed in detail, is enriched in yttrium plus the lighter rare earth elements.The basal low-sulfur lithotypes are dominated by arboreous lycopod spores. The middle, low-sulfur portion of the bed is dominated by herbaceous lycopsids (Densosporites) at the base of the unit and becomes increasingly enriched in Lycospora towards the top of the unit indicating that the peat-forming environment became wetter. The greatest arboreous lycopod spore abundances in the upper, high-sulfur portion the bed, along with an overlying marine roof, indicates that peat deposition was terminated by a marine inundation.  相似文献   

11.
《Applied Geochemistry》1997,12(3):281-289
The Middle Pennsylvanian Breathitt Formation (Westphalian B) Pond Creek and Fire Clay coal beds are the 2 largest producing coal beds in eastern Kentucky. Single channel samples from 22 localities in the Pond Creek coal bed were obtained from active coal mines in Pike and Martin Countries, Kentucky, and a total of 18 Fire Clay coal bed channel samples were collected from localities in the central portion of the coal field. The overall objective of this study was to investigate the concentration and distribution of potentially hazardous elements in the Fire Clay and Pond Creek coal beds, with particular emphasis on As and Pb, 2 elements that are included in the 1990 Clean Air Act Amendments as potential air toxics. The 2 coals are discussed individually as the depositional histories are distinct, the Fire Clay coal bed having more sites where relatively high-S lithologies are encountered. In an effort to characterize these coals, 40 whole channel samples, excluding 1-cm partings, were analyzed for major, minor and trace elements by X-ray fluorescence and proton-induced X-ray emission spectroscopy. Previously analyzed samples were added to provide additional geographic coverage and lithotype samples from one site were analyzed in order to provide detail of vertical elemental trends.The As and Pb levels in the Fire Clay coal bed tend to be higher than in the Pond Creek coal bed. One whole channel sample of the Fire Clay coal bed contains 1156 ppm As (ash basis), with a single lithotype containing 4000 ppm As (ash basis). Most of the As and Pb appears to be associated with pyrite, which potentially can be removed in beneficiation (particularly coarser pyrite). Disseminated finer pyrite may not be completely removable by cleaning. In the examination of pyrite conducted in this study, it does not appear that significant concentration of As or Pb occurs in the finer pyrite forms. The biggest potential problem of As- or Pb-enriched pyrite is, therefore, one of refuse disposal.  相似文献   

12.
Roof successions above two coal seams from the Mansfield Formation (Lower Pennsylvanian) in the Indiana portion of the Illinois Basin have been studied with regard to sedimentary structures, organic petrology and organic geochemistry. The succession above the Blue Creek Member of the Mansfield Formation is typical of the lithologies covering low-sulphur coals (< 1%) in the area studied, whereas the succession above the unnamed Mansfield coal is typical of high-sulphur coals (>2.%). The transgressive-regressive packages above both seams reflect the periodic inundation of coastal mires by tidal flats and creeks as inferred from bioturbation and sedimentary structures such as tidal rhythmites and clay-draped ripple bedforms. Geochemistry and petrology of organic facies above the Blue Creek coal suggest that tidal flats formed inland in fresh-water environments. These overlying fresh water sediments prevented saline waters from invading the peat, contributing to low-sulphur content in the coal. Above the unnamed coal, trace fossils and geochemical and petrological characteristics of organic facies suggest more unrestricted seaward depositional environment. The absence of saline or typically marine biomarkers above this coal is interpreted as evidence of very short periods of marine transgression, as there was not enough time for establishment of the precursor organisms for marine biomarkers. However, sufficient time passed to raise SO42− concentration in pore waters, resulting in the formation of authigenic pyrite and sulphur incorparation into organic matter.  相似文献   

13.
Seams from the St. Rose and Chimmey Corner coalfields, Nova Scotia, Canada, were sampled and examined for petrographic and geochemical composition. Rank determinations indicate a rank of high volatile C-B bituminous. Seams show regular alternations of dull and bright microbanded lithotypes, with dull lithotypes predominant in the central portion of the main seam (No. 5 seam). Brighter lithotypes are dominated by vitrinite (>80%), with minor inertinite (avg. 12%) and minor liptinite. Duller lithotypes contain greater amounts of inertinite (up to 40%) and liptinite (primarily sporinite). Mineral matter consists of epigenetic pyrite, with lesser amounts of clay and quartz. Cabonates are common in the Chimney Corner seams. Elemental composition of the seams is similar to other Canadian coals and fall within world coal ranges, with the exception of high concentrations of Cl, Zn, Ni, Mo, Pb, Cu and As.Depositional environment of the seams as indicated by maceral composition, lithotypes and geology suggest a predominance of wet forest to reed moor conditions, in a fluvial-lacustrine setting. Periodic episodes of flooding and drying are indicated by lithotype, maceral and mineral variations.  相似文献   

14.
The Pittsburgh coal was sampled with three columns of oriented blocks in two adjacent surface mines in Harrison Co., WV and one column of 15-cm increment samples from an outcrop 50 km to the northeast in Monongalia Co., WV. Each of the oriented blocks was described as to lithotype. Lithotype bands continuous across the blocks were sampled and analyzed for maceral and mineral matter content. Each of the 15-cm increment samples was also analyzed for maceral and mineral matter. The individual lithotypes were compared as to maceral and mineral matter content between the two benches of the Pittsburgh coal and between the three columns.The data were converted to equal 10-cm intervals by stratified random sampling. Petrographic zones were established based upon stratigraphic variations in maceral group and mineral matter content. The lateral continuity of the zones were observed over short (75 m), intermediate (575 m) and long (50 km) distances.The geochemical environment of deposition of each zone observed in the column samples was interpreted based upon the maceral and mineral matter content and the chemical coal model presented by Renton and Cecil (1979).  相似文献   

15.
用配有自行研制的程序控温仪的显微热台,观察研究了P1、T3两时代煤显微组分的加热性状和焦炭的显微特征,由此揭示了不同时代等变质煤结焦性差异的原因,提出了标准活性组分（Vt,st）的新概念;确定了测定混煤中镜质体反射率的方法;最后以重钢焦化厂大量200kg焦炉试验为基础,用计算机进行数理统计分析,优选出标准活性组分（Vt,st）、镜质体随机反射率（Rran）及其标准差（S）三个参数,建立了能准确定量预测焦炭机械强度的数学模型。经焦化厂使用证实,用该方法预测和控制焦炭强度不但准确度高、简单易行,而且可适用于我国大多数焦化企业由不同煤田的多矿点供煤且常有混煤、煤质不稳定的复杂状况。  相似文献   

16.
The Obed-Marsh coal deposit is of Late Paleocene age, and contains over 200 million tons of subbituminous-B to high-volatile bituminous-C coal.Petrographic analysis of three sections from seams 1 and 2 reveals high amounts of huminite and relatively low amounts of liptinite and inertinite, with the exception of some intervals in both seems. The persistent high ratio of huminite to liptinite and inertinite indicates a relatively reducing environment, a feature also expressed by the relatively low inertinite content. Examination of the in-seam profiles also indicates undisturbed peat accumulation over long periods of time.The Obed coals, similar in rank and composition to the Hat Creek coals of British Columbia, formed in a freshwater environment and can be used as feedstock for combustion/gasification. Furthermore, the intervals rich in liptinite and petroleum-like substances may be utilized for liquefaction (hydrogenation).  相似文献   

17.
Rock-Eval pyrolysis was performed on lithotype and depth profiles of Tertiary brown coals and a coalification profile of Permian bituminous coals. The humic acid and kerogen fractions from the coals are also investigated by this technique along with the effect of base extraction on the kerogen fraction. Structural variations between brown coal lithotypes are primarily reflected by changes in Oxygen Index Value. This result was supported by the results from the depth profile (same lithotype). A wide range of Hydrogen Indices (independent of depth) but similar Oxygen Indices were observed. The results from the Qualification profile show that the Oxygen Indices varied with rank, whereas Hydrogen Indices show a greater dependence on coal type. A plot of HCversus Hydrogen Index produced good correlations with the brown (0.77) and bituminous (0.90) samples lying on two separate lines intersecting at high H/C. This result (and higher correlation for bituminous samples) reflects the expected dependence of hydrogen index on oxygen content (present primarily as hydroxyl groups). A high correlation (0.95) between quantitative IR data (K 2920 cm mg?1) and Hydrogen Indices supports previous conclusions regarding the dependence of Hydrogen Indices on the aliphatic structure of the samples.  相似文献   

18.
The experimental conditions allowing quantitative interpretation of liquid state 13C-NMR spectra of the humic acids, derived from the five Victorian brown coal lithotypes are described. The structure of the two classes of humic acids investigated for each lithotype vary significantly in their level of aromaticity, the level of polar functional groups and aliphatic chains attached to their polyaromatic skeletons. Variation is also observed in the degree of aromaticity and oxygen-containing functions of humic acids with lithotype. These data are interpreted in the light of paleobotanical evidence, which suggests that the lithotypes represent variations in depositional environment and input to the coal seam.  相似文献   

19.
The petrographic maceral composition and vitrinoid reflectance of bituminous coals have been correlated with their carbonization characteristics and are widely used to predict how coals will perform in the coking process and to calculate the strength of the resulting coke. As a result, there is a growing dependence on coal petrographic data in characterizing coals for cokemaking. In addition, there is a growing awareness that there are other nonmaceral microstructures in coal such as material size, shape, association, fracturing, and weathering which should permit better characterization of coals when properly interpreted. These nonmaceral microstructures also give an insight into the metamorphic history and changes due to burial and exhumanation.To expand the use of coal petrologic and petrographic data, a new analytical procedure has been developed that requires the microscopic determination of such nonmaceral microstructures as normal coal, coal fines, pseudovitrinoids, microbrecciation, oxidation, coarse mineral matter, miscellaneous materials, and contamination. The occurrence of one or more of these microstructures in coal, depending on their kind and abundance, may have a significant effect on the coal performance in various processes. This work has resulted in formulation of a technique for determining the nonmaceral microstructures in coal and, if applied as a supplement to the routine maceral analysis of coals, should help in explaining the anomalous behavior of some coals.  相似文献   

20.
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