Coal Classification Research Articles

An approach to classification of coal with electron spin resonance parameters.

電子スピン共鳴(ESR)法により石炭の分析を行い,ESRスペクトルの解析から求めた種々のパラメーターを一括して用いることにより,石炭の特徴を把握できるかどうか検討した.ESRパラメーターは,フリーラジカルのg値,線幅,飽和曲線マイクロ波出力値,スピン濃度,及び,マンガン(II)のシグナル強度の計5種類である.このパラメーターを総合的に取り扱うために,パターン認識法を用いたが,その一つの方法である非線形変換プロット法の結果は,ESRパラメーターによる石炭の特徴把握と分類の可能性を支持した.又,K-nearest neighbor法及び学習機械法により,石炭の分類と性質予測を検討した.

ソ連炭の統一分類法

National Standards (GOST 25543-82) for unified classification of coals were established in USSR on December 20, 1982 as outlined in this report.First, brown coal, bituminous coal and anthracite are classified by appearance using three kinds of parameters.Next, classification into four stages-class, category, type and subtype-is made using parameters based on the genetic and industrial properties of coals followed by further division of each stage into several levels, all with systematic numbering. As a result, individual coal is represented by a seven-digit code number.Then, coals are classified into three groups-mark, group and subgroup-with their general industrial properties as criteria and individual coals are shown by their code numbers in the “industrial classification chart of coal”.Lastly, a guidance is provided for rational application of each coal and the testing methods are specified for determining the classification parameters.

Fluidized bed gasifier or similar device for simultaneous classification of ash and unreacted coal

Fluidized bed gasifier or similar device for simultaneous classification of ash and unreacted coal

Analysis of coal fly ash properties of importance to sulfur dioxide reactivity potential

Twenty-two fly ashes selected to provide a representative cross-section of coal classification and combustion techniques were analysed for physical and chemical characteristics that might indicate a potential for reaction with SO/sub 2/ in a flue gas desulphurisation process. Each ash was tested for its SO/sub 2/ removal potential as a slurry injected into a 1000 ft/sup 3//min spray dryer/fabric filter pilot plant. The reactivity of the fly ashes correlated with a combined effect of total slurry alkalinity in conjunction with the available surface area which suggested a surface-controlled reaction. The results further suggested that the utilisation of slower reacting alkaline species such as carbonate could be enhanced by a longer contact time with the flue gas such as is provided in a baghouse filter operation.

Classification of fine coal with a hydrocyclone

The classification performance of a 225-mm hydrocyclone has been investigated. Coal slimes of a nominal 0.5 mm size consist were classified in the separation-range of 0.070 mm to 0.250 mm at solids contents from 6 to 35% by mass, and flow rates of 200 to 700 1 min −1. The partition curves obtained were analysed in terms of the water split to the oversize flowstream, the corrected separation size and the reduced partition curve. The results can be summarised as follows: 1. (1) The water split to the oversize flowstream was found to be dependent upon the vortex finder and spigot diameters of the hydrocyclone and the flow rate and pulp density of the feed slurry. 2. (2) The corrected separation size was dependent on the solids content of the feed, and the vortex finder and spigot diameters. The hydraulic pressure (or flowrate) of the feed slurry did not have a significant effect. This phenomenon could be explained using the crowding theory of Fahlstrom. 3. (3) The reduced partition curve obtained for this coal sample was independent of the hydraulic pressure and solids content of the feed slurry, the diameters of the vortex finder and spigot, and the proportion of near-size material. This reduced partition curve was similar to that found by Lynch and Rao for silica and limestone. The solids content of the slurry was the major factor in determining the partition curve of the hydrocyclone.

Fundamentals of the Metallurgical Coke Making (I)

The fundamentals of metallurgical coke making are reviewed in four instalments. This paper, Part I, describes (1) petrographic components and properties of coal as organic sediments, (2) chemical and physical structures of coal as high molecular weight organic compounds consisting of C, H, and O, and behavior during heating, and (3) classification and characterization of coal.

Clustering on a microcomputer with an application to the classification of coals

The widespread introduction of microcmputers in laboratories where large data sets are more and more frequently gathered, makes it necessary to be able to use adapted statistical software. This paper describes a BASIC program for the Macnaughton-Smith clustering method adapted to the Apple II microcomputer. Experience is reported of an application of the program to the classification of a set of coals.

The combination of multi-element neutron activation analysis and multivariate statistics for characterisation in geochemistry

Instrumental neutron activation analysis provides an accurate method for the determination of some 20 to 40 elements in geological samples. This method has been combined with pattern recognition techniques to provide a powerful method for the study of geochemical differences and for the classification of unknown samples. Discriminant analysis, a statistical method of pattern recognition, was applied to the study of mineralisation in granites, to the classification of diamonds, to the identification of sedimentary units from the Witwatersrand and to the classification of coals from the Witbank Coalfield in South Africa. The results show that the methods can be used to identify and map the mineralised phase of the granite. In the case of the diamonds trace element signatures were found which were characteristics of the sources and these were used to classify very pure unknown samples with a high rate of sucess. In both the coal and particularly in the case of the Witwatersrand sediments these methods showed themselves to be a powerful tool for the identification of sedimentary units.

Effect of thermal treatment on the interaction of brown coal and water: a nuclear magnetic resonance study

Proton nuclear magnetic resonance ( 1H n.m.r.) has been used to measure changes in the water-binding capacity of bed-moist brown coal lithotypes subjected to heat treatment. A rapid reduction in the coal-water interaction was found to occur at treatment temperatures /s> 420K. A Pale lithotype was found to lose more water-binding capacity than a Dark lithotype of the same coal for a given heat treatment. It is suggested from the present work that n.m.r. testing could be useful for the classification of brown coals.

Status of Geologic and Resource Mapping, Northwest Quadrant, Circum-Pacific Map Project: ABSTRACT

A draft of the Geologic Map was completed in 1978 with the End_Page 978------------------------------ cooperation of the national geological services of the Northwest Pacific Region. While awaiting publication, new geologic maps for various areas have been published and the draft has been revised accordingly. However, the basic geologic subdivisions of the map are becoming somewhat obsolete and the Panel is exploring ways to cope with the problem. Drafts of the Tectonic Map have been provided by the countries of the Northwest Region. The Panel is in the process of preparing a unified standard for the region. A sample of the Mineral Resources Map with a tectonic background was prepared for the southwestern part of the Northwest Region Acquisition of published data on China and the USSR has been completed and the information is ready for plotting. The plotting of coal occurrences for the Energy Resources Map from data provided from countries of the Northwest Region and from published information is nearing completion. There are some inconsistencies in coal classification among data received from different countries, but it is not practical to aim for complete unity throughout the region. Data on oil and gas have been acquired and can be plotted in accordance with the publication schedule. Regarding geothermal energy, published heat flow data have been plotted on a different projection. A gravity anomaly map on a different projection has been prepared for areas with published gravity data for inclusion on the Geodynamics Map. End_of_Article - Last_Page 979------------

Classification of bituminous coals: Application of the technique of optimal sections in coal classification

Optimal sections have been applied to the classification of bituminous coals according to the magnitudes of the parameters V r and ( G) R. I. , which reflect metamorphism and caking properties of coal, respectively. The points at which the sections are divided and the number of groups are determined on the basis of the diameter of the group and the minimum error function. Coincidentally, all of these section points correspond to changes in the petrographic characteristics during the genesis of bituminous coal. The section points corresponding to V r are 20, 28, and 36%. These points divide the coal into four groups, namely low, medium-low, medium-high, and high-volatile bituminous coals. Considering coking properties, the section points on the basis of the value of ( G) R. I. are 5(20), 40(60), and 75(90). These points also divide the coal into four groups, namely, non-caking, weakly-caking, medium-caking, and strongly-caking coals. When subdivisions are made, the coals may be put into seven groups, viz. non-caking, slightly-caking, weakly-caking, medium-caking, medium-strongly-caking, strongly-caking, and extra-strongly-caking coals. Thus, a natural classification is formed and a numerical system can be used for classification.

Coal Blending Theory-Retrospect and Prospect

This paper summarizes a series of experimental studies conducted by the author et al., on coal blending theory which is a basic condition for the production of coke. A brief history is given of the condition of coking coal supply and past studies undertaken in Japan ranging from the establishment of basic concepts of coal blending in the period immediately after World War II to recent trends in the search for blending standards aiming at the improvement of hot properties of coke. The essential point in coal blending is to obtain uniform, strong-textured coke as a composite material by an optimum combination of various grades of coal having different heating properties, i.e., thermal transformation temperatures. With the above-mentioned in mind, the paper describes the classification of single coal on the basis of the blending theory, the estimation of coke strength, and the theory for size control of coal charge. Finally, the relation among coal blending, coke texture, reactivity with CO2, and strength after the reaction with CO2 is described, indicating the importance of future efforts for the improvement of hot properties of coke by the addition of caking additive.

Dependence of coal liquefaction behaviour on coal characteristics. 5. Data from a continuous flow reactor

A classification of coals in which conversion in batch reactors at 400 °C with tetralin (but no H 2 gas) is one classifying parameter, is shown to be highly significant when the coals are hydrogenated in a 1 kg h −1 continuous flow reactor at 440 and 455 °C with 20.7 MPa of hydrogen. Regressions of the two sets of data against each other show variances explained of 86.5 and 88%, respectively. The yield of material distillable under standard conditions in a vacuum varies over the range 12–60% of dmmf coal.

Optical anisotropy of carbonized coking- and caking-coal vitrains

The purpose of this work was to characterize in detail the optical anisotropy formed during carbonization of the range of coals used in the coking industry, the ultimate objective being to attain a better understanding of the coking process. Vitrains hand-picked from a series of coking and caking coals were carbonized to various temperatures between 380 and 1000 °C. The semicokes and cokes so produced were examined by polarized-light microscopy to determine the proportions of the different types of optical anisotropy developed during carbonization. The results demonstrated that coals normally grouped within one class of the coal classification system used by the National Coal Board can lead to cokes which are significantly different in terms of their optical anisotropy. The process of the anisotropic development during carbonization can be explained generally in terms of loss of volatile matter, variations in viscosity of the plastic mass, and distortion of ordered phases by the pressure of evolving gases. Differences in carbonization behaviour as judged by the coke anisotropy can be attributed to differences in the ‘molecular-structure’ of the parent coal. In this respect the oxygen in the coal is considered to be of primary significance.

An alternative representation of coal composition data

The two best known coal composition charts are Seyler's plot of mass percent hydrogen versus mass percent carbon, which has been much used for coal classification, and van Krevelen's plot of atomic H/C ratio versus O/C ratio, which has proved useful in the study of coalification. For the more general problem of the study of conversion of coal to other materials it is suggested that a ternary carbon/ hydrogen/oxygen diagram be used. In particular it is advocated that the compositions be plotted as bond-equivalent percentages, i.e. with each element given a weighting appropriate to its power of combining with the other elements. The construction and use of the diagram are demonstrated, taking as an example the problem of the conversion of brown coal to oil.

Classification of Coking Coal in USSR

The well-known GOST systems for classification of coking coal are used by each coal mine, but there are many deficiencies regarding their application to examine the interchangeability of coals.Therefore, the unified classification system for USSR coals is presently being studied. Two methods for the unified classification are proposed, depending on discrepancies in classification parameters used; one is the system based on processing properties of coal (volatile matter, y index, etc.), the other is based on genetic properties of coal (maceral content, etc.).Moreover, proposals by Dnepropetrovsk-groups and reports on classification trials for low-volatile non- or weakly-coking coals are mentioned in this report. At the end of the report, the characteristics and technological significance of classification parameters, which are the key points of coal classification, are reviewed and summarized.

Classification of coking coals

None of the established coal classification systems was specifically designed to meet the requirements of the modern blast furnace coke producer. Meanwhile, more stringent blast furnace coke specifications have demanded sophisticated coal blending plants and close control of coal blend quality. A coking coal classification system ∗ based on reflectance and dilatation is proposed for classifying single coals or coal blends with individual macrocomponents of similar rank and dilatation. Coals are grouped into classes which can be represented by four digit numbers, the first two integers representing the reflectance and the last two integers the dilatation. The basic parameters are already widely used as quality-control tools at coking plants and the procedures for their measurement are currently being standardized in the United Kingdom. It is suggested that the proposed classification system substantially fulfills the requirements of the coke-maker in that it is sensitive to small changes in coal composition and condition and the parameters used can be correlated with coke physical quality. The time appears to be opportune therefore for the implementation of such a classification system for the more efficient control of coal preparation and blending at coking plants.

Classification of coals according to degree of coalification by reflectance of the vitrinite component: a clarification

Classification of coals according to degree of coalification by reflectance of the vitrinite component: a clarification

Pneumatic classification of slack coal

The removal of fines from small grades of sub-bituminous coal improves the performance of these coals in stoker firing. In the preparation of these industrial slack grades in New Zealand, there is no need for washing and the coals are relatively dry. Pneumatic classification has therefore been investigated on a semi-commercial scale with the objective of effecting a separation at a particle size of about 2.5 mm. The work has shown that relatively high efficiencies of size separation can be achieved. The results are applied to the design of commercial equipment.

Studies on the Determination of Carbon Dioxide in Coals (II)

The authors have studies in the first report on the pressometric and gravimetric methods for the determination of carbon dioxide in coals and concluded that the modified pressometric method (ISO/TC 27-490) was suitable for the specification in JIS.It is necessary to specify a scope and tolerances when a method is accepted in JIS. The authors, therefore, have studied for this purpose, and concluded as follows:1) The carbon dioxide evolved when low rank coals which belong to class III (Subbituminous) and IV (Lignitic) in ASTM D 388 “Classification of coals by rank” are treated with hydrochloric acid does not usually originate from carbonate minerals. These low rank coals, therefore, should be omitted from the scope of the JIS.2) Tolerances calculated from the results of interlaboratory experiment are shown in the next table with that of other standards. The precisions of this method are consi-dered as fairly good figure in comparison with that of other standards.The draft JIS M 8813-1972 has been prepared based on the above studies, and it will be published in the end of 1972.