Journal of the Fuel Society of Japan
Online ISSN : 2185-226X
Print ISSN : 0369-3775
ISSN-L : 0369-3775
Volume 45, Issue 12
Displaying 1-14 of 14 articles from this issue
  • [in Japanese]
    1966 Volume 45 Issue 12 Pages 823
    Published: December 20, 1966
    Released on J-STAGE: June 28, 2010
    JOURNAL FREE ACCESS
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  • Yasuo Sasa
    1966 Volume 45 Issue 12 Pages 824-832
    Published: December 20, 1966
    Released on J-STAGE: October 21, 2011
    JOURNAL FREE ACCESS
    The Ishikari Coalfield in the central part of Hokkaido is the most important, productive coalfield in Japan with about 2500 squarekilometers of total area. It is built of early Eocene-middle Oligocene deposits, known as the Ishikari Group, including several formations, with thickness up to almost 3000 meters. These formations are mostly of non-marine origin with numerous workable, high quality coal seams and a few are of marine facies. (Fig. 1)
    The Ishikari Groop is underlain by the 6, 000 meters thick Cretaleous marine sediments named Ezo-and Hakobuchi group and is overlain by the upper Oligocene marine Poronai Groop, 1, 600 meters in thickness, being bounded both ends by slight ungular unconformity. The Ishikari coal basin is observed to lie in between of the Cretaceoos Yezo-geosynclinal basin on the east and the Oligocene Poronai embayment on the west. This migration of basins since Mesozoic time down to later Tertiary date shows the westward propagation of crustal movement which is a part of the Alpine orogenic chain (Fig. 2). These coalbearing formations are the product of very calm period in the middle Paleogene Tertiary, just after the extensive Cretaceous transgression and before the marine invasion of late Paleogene period. This tendency, namely, coal basins are usually provided between or, just after crustal movements, is universally acceptable at various parts of the world throuogh ages.
    The coal basin was formed, paleogeographicaly, by gentle, broad downwarping of wide, very flat area like peneplain which developed between Cretaceous and Tertiary interval. Local depressions, embayments and barriers were existed at places. (Fig. 3) Sinking of basins at various stages of the Ishikari epoch were took place very gently, mostly not so deep, and intermittently, changing center of subsidence, so as to yield cyclothems and also suitable to accumulate plant materials which formed coalseam in later stage.
    From paleogeological point of view, during the period of Ishikari basin, exposed rocks on the eastern backland were of Cretaceous and Pre-Cretaceous sediments, part of which metamor phosed into schist and migmatitic gneiss, being accompanied by granitic rocks and basic to ultrabasic Intrusive rocks such as serpentinite. This kind of rocks are evidenced by examining heavy minerals in sandstones aud also pebbles in conglomerates in the Ishikari group. It also suggests us the rising up and exposition of Hidaka and Yubari mountains at that time. On the contrary, exposures of Pre-Cretaceous beds with granitic intrusive mass, with effusive rocks such as rhyolite, andesite and basalt are proved to exist on the western land area. (Table 1)
    Vegetations prevailed at the Ishikari period, as recognised by fossils of plant leaf and pollen, were mainly of mixture of Arcto-Tertiary Geoflora and Paleo-Tropical Geoflora with genus of temperate zone with occasional intermixing of warm-temperate ones. This reminds us the climate of that time as that of north Formosa or Okinawa Islands. Only a slight changes of flora were observed throughout the Ishikari period, being a little warmer in the middle and got a little cooler climate at the close of that age. Almost all plant species were of lowland habit and it is also noticeable that a very few species were of waterflooding area.
    Coal seams were formed by accumulation of plant materials when the watered area were shallow enough to grow vegetation, repeating growingup, falling down and also by partial transportation. Plant seams were laid down not so high and not so low from water level, during pause of subsidence long enogh to fill up basin by sedimens, after a gentle sinking. (Fig. 4) Intermittency of subsidence and deposition and its repetition were shown by existence of cyclothems in coalbearing foromations of the Ishikari group.
    Three facies of plant deposition as seams are able to classify from mode of occur rence of coal seams and from coal petrographical point of view.
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  • Shunji Watari
    1966 Volume 45 Issue 12 Pages 833-838
    Published: December 20, 1966
    Released on J-STAGE: February 23, 2011
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    The frequent occurrence of silicified erect stumps or lying trunks (commonly called “Matsuiwa”) in the coal seams makes a particular feature of the coal fields (Palaeogene) which are developed in a wide-spread area of the northern part of Kyushu Island. In observing through a considerable number of specimens obtained from several important coal-fields, I found that all of them belong to one and the same species which should be considered as a new taxon of Taxodioxylon in a wide sense (Taxodioxylon matsuiwa Watari in Bot . Mag. Tokyo, 79. 165-173, 1966). On the other hand, the clastic sedimentary strata of the Palaeogene of this area also contain the fossil woods abundantly and result of observations on these woods makes us possible to suppose the existence of laxuariant flora rich in dicot trees under warm-temperate or subtropical climate. It may highly be possile to assume, under the mutual supports presented by these palaeobotanical evidences and many geological investigations, that Taxodioxylon matsuiwa ever consisted the pure and swampy forests resembling those of the moderen Taxodium or Glyptostrobus in the growing habit.
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  • Shigemoto Tokunaga
    1966 Volume 45 Issue 12 Pages 839-842
    Published: December 20, 1966
    Released on J-STAGE: June 28, 2010
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    The uraniferous carbonaceous matters are found in some places in Japan where tertiary starata distribute on granite mass.
    The Ouchi area, Miyagi Prefecture is one of the remarkable place for presence of uraniferous coal. The pajynological survey on the Ouchi coal has done systematically. According to the result, many miocene-type pollen and spores are found from the coal. Other paleobotanical data are obtainted by fossil leaf impressions, found from the strata overlied the coal seam. The paleoclimate during the deposition of the coal seam is supposed a warm-temperate.
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  • Effect of Crystalline Mineral Matter in coal on the Grindability
    Toshihiko Maruyama
    1966 Volume 45 Issue 12 Pages 843-850
    Published: December 20, 1966
    Released on J-STAGE: June 28, 2010
    JOURNAL FREE ACCESS
    The grindability of high ash coal seems to be influenced by the mineral matter in coal as well as coal petrographic constitution etc. It is discussed in this paper on the gridability of the high ash coals, especially how crystalline minerals in coal have influence on the grindability. Each coal after sieving into 16×30 U. S. mesh was ground by the Hard grove mill so that more than 70% of original weight would pass through a 200 U. S. mesh sieve, removing the fines which was passed through a 200 mesh sieve at each 60 revolutions. The fines and the residue were appropriated to quantitative estimation of crystalline minerals by means of X-ray analysis and measurement of ash content. Petrographic analysis and microscopic observation were done for the original coals and their residual ones.
    From these experimental results the influence of each mineral on the grindability is summarized as follows:
    Quartz: The influence of quartz on the grindability varies with the mode of occurence in coal. In the case of the sample in which quartz occurs as fine grains (less than about 50 microns across), the grindability seems to be unaffected directly by quartz, while it occurs as comparative coarse grains (more than 100 microns across), the grindability seems to be subject to a bad influence.
    Carbonates: Calcite, aragonite and dolomite appears to have similar influence on the grindability. In the case that the thin films composed of very fine crystals of carbonates occur reticulately in coal, their existence seems to have a favorable effect on the grinda bility, however the grindability seems to be rather subject to a bad effect in the case that carbonate menerals occur as comparative coarse grains.
    Feldspars: Plagioclase was only found as feldspar mineral in a few coals. The influence of plagioclase on the grindability appears to be similar to the case of quartz.
    Clay minerals: Kaolin minerals, illite and montmorillonite were detected mainly within coaly shale and shale. However the effect of these minerals on the grindability is not distinct.
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  • Torajiro Honma, Mitsuru Yamamoto, Hiroyuki Iwata, Kaoru Masuda
    1966 Volume 45 Issue 12 Pages 851-858
    Published: December 20, 1966
    Released on J-STAGE: June 28, 2010
    JOURNAL FREE ACCESS
    The internal friction of ultraifine coal was measured, and then the flow curve, the apparent viscosity and the yield value were measured too for both the fixed bed of ultra-fine coal and the fluidized bed.
    The coefficient of internal friction and the cohesive force were from 0.6 to 0.7 and from 70 to 80 g/cm2 respectively for the ultra-fine coal. These values were smaller than that of the wheat sold in the markets and larger than that of the standard sand. In case the ultra-fine coal becomes small in its size range, the internal friction of it decreases and the cohesive force of it increases.
    The flow curve is obtained from the shearing stress and the shearing rate, and it was considered that the fixed bed of urtra-fine coal shows the dilatant flow curve and would be the rheological pseudoplastic.
    The apparent viscosity for the ultra-fine coal increases in the case of increasing of the external force, and this becomes constant value in case of the external forcebe comes over the constant value. The fluidized bed shows the Newtonian flow because the viscosity of it is similar to that of water under the condition of the gas velocity of from 1 to 2 cm/sec.
    The yield value of fixed bed is very large in comparison with the other fluid, and this value increases in case of the large size range. The yield value decreases remarkably for the fluidized bed, and this value becomes about zero under the condition of the gas velocity of some 0.3cm/sec.
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  • Nuclear Magnetic Resonance Spectroscopy
    Hiroshi Kauai, Akira Suzuki, Mitsuomi Ito, Gen Takeya
    1966 Volume 45 Issue 12 Pages 859-867
    Published: December 20, 1966
    Released on J-STAGE: June 28, 2010
    JOURNAL FREE ACCESS
    As part of a series of studies of coal constitution based upon the hydrogen distribution of coal extracts from their NMR spectra, in the present paper the constitution of quinoline extracts of Yubari coal were studied. The coal sample was prepared as follows:
    Lump Yubari coal obtained directly from Yubari No.2 Mine was crushed and processed with a ZnCl2 solution of a specific gravity of 1. 24. A very low ash coal sample was obtained and its yield was 69 percent of the parent lump coal. This was used for the present study of coal constitution.
    The coal sample was extracted with quinoline at 300-400°C for 4 hrs. under a pressurized atmosphere of nitrogen. The yield of quinoline extracts, after being separated from the solvent and died, was 90-98 percent of the coal sample. In order to prepare the samples for the measurement of NMR spectra of the quinoline extracts in deutero-py ridine solvent, the quinoline extracts were again extracted with pyridine at room tempe rature. The yield of pyridine extracts thus obtained was 32-75 wt.percent based upon the dry Yubari coal sample (Tables 1 and 2). The pyridine extracts above described and a pyridine extract obtained directly from the Yubari coal sample itself were redissolved into deutero-pyridine, C5D5N. The C5D5N solutions (approx. 10 wt. %) of these coal extracts thus prepared (NMR Samples No.1-5) were examined b NMR spectroscopy at 60Mc. From the contents of the different types of hydrogen atoms estimated from NMR spectra and the result of elementary analysis, various structural parameters were given for the coal extracts, i. e. NMR samples No.1-5 (Table 6). In the mean structure as revealed from these structural parameters, there seems to be only a slight difference between the quinoline extracts (NMR samples No.1-4) and the direct pyridine extract (NMR sample No.5). However a detailed consideration shows that the carbon aromaticity and the average number of condensed aromatic rings in the mean structure of these coal extracts tend to increase with the temperature level of the quinoline extraction of coal.
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  • Helium Density of Heat Treated Coal
    Shuya Fujii, Toshiharu Shinbata
    1966 Volume 45 Issue 12 Pages 868-875
    Published: December 20, 1966
    Released on J-STAGE: June 28, 2010
    JOURNAL FREE ACCESS
    The true densities of Japanese heat treated coals are measured with helium and these results are compared with those obtained from foreign heat treated coals, Japanese original coals and foreign original coals. The density is measured with the same apparatus used for original coal, as reported previously. For this experiment, five sample coals of different rank are used, which have been heat treated at various temperatures from 200°C to 500°C.
    In Japanese coals, the change in density with heat treatment temperature is sum marized as follows. For the four coals except Tempoku coal, below 350°C there is no appreciable chang in density, which however begins to increase at 350°C and shows rapid increase from 400°C to 450°C. Between 450°C and 500°C, the increase in density becomes milder. For Tempoku coal, no appreciable change is observed below 400°C and density begins to increase at 450°C.
    The change in density of heat treated coal with C% is very different from that of original coal with coalification. When the reciprocal of density is plotted against the hydrogen content, Japanese heat treated coals and foreign heat treated coals are found to lie on the same curve, and the end of the curve (H%=O) coincides with the point of graphite. Moreover, the curve nearly agrees with that of original coals.
    In addition, according to van Krevelen's graphical densimetric method, the aromatic carbon fraction (fa) is calculated from the measured density and the relation between fa and heat treatment temperature is obtained. For Tempoku coal which is the lowest in coal rank among the samples, fa increases gradually with the elevation of heat treatment temperature from 200°C. Yubari coal and Hashima coal which are situated at higher coal rank, do not indicate any appreciable change in fa below 400°C, but begin to show increase at 400°C. Taiheiyo coal and Bibai coal located in the middle of coal rank, exhibit an intermediate property.
    The value of fa is plotted against H/C atomic ratio and it is found that the points of Japanese heat treated coals and foreign heat treated coals lie on the same curve. Besides, the curve nearly agrees with that of the original coal.
    In conclusion, the density and fa of heat treated coal are greatly affected by its hydrogen content and by making use of this relation, density and fa of heat treated coal can be determined approximately.
    The aromatic carbon fraction of heat treated coal increases with its heat treatment temperature. If the increase of fa is ascribed to the distillation of the low molecular substances containing much aliphatic structure, fa of each heat treatment temperature can be calculated. As a result, for the four samples except Tempoku coal, the calculated value agrees approximately with the experimental value.
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  • Electron Spiu Resonance of Coals
    Sadaharu Toyoda, Sachiko Sugawara, Hidemasa Honda
    1966 Volume 45 Issue 12 Pages 876-883
    Published: December 20, 1966
    Released on J-STAGE: October 21, 2011
    JOURNAL FREE ACCESS
    The twelve Japanese coals over the range from lignite to anthracite, and six foreign coking and caking coals and anthracite were elected as coal sample. It seems to he considered from the shape variation due to saturation effect that ESR signal for foreign coals in vacuum (d.a.f. C=87.6%-90.7%) consists of at least two components. One of them is a broad component and the other is a narrow component. The latter is very sensitive to oxygen gas and disappears in air. The change due to oxygen gas is reversible. The value of peak.to.peak line width (ΔHmsl) for the latter is about 1-2 gauss and the spin center concentration is about 2-5×1017 spins/g. All the ESR signals show homogeneous saturation, althou gh it is vague for the signal consisting of two comonents. The spin-lattice relaxation time (T1) shows a maximum at about 86% C, which is slightly lower value than that obtained by Smidt and D. W. van Krevelen. The line width for Japanese coal bellow about 86% C is slightly broader as compared with their results. This result seems to be due to higher hydrogen content of Japanese coal . Above about 90% C, the spin center concentration (N) rapidly increases, the line width rapidly decreases and the shape of absorption line changes from Gaussian type to Lorentzian type . The N decreases with the increase of the volatile matter content and increases with the aromatic carbon fraction. The latter fact seems to show that the spin center concentration is connected with the formation of aromatic ring system.
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  • Knoop Hardness of Originals and Heat Treated Coals
    Hidehiko Sugimura, Masahito Shiwa, Yuzo Sanada
    1966 Volume 45 Issue 12 Pages 884-891
    Published: December 20, 1966
    Released on J-STAGE: June 28, 2010
    JOURNAL FREE ACCESS
    The measurments of hardness are a very available mean in the study of rheological properties of coal. It is well known that the hardness of coal, changes with rank and that the hardness of heat-treated coals has a maximum at heat treatment temperature (HTT) of about 1, 200°C. It apPears, however, that very few detailed inves tigations of hardness of heat-treated coals in the early state of carbonization have yet been made. The present authors measured the Knoop hardness of 17 coals of every rank and that of coals heat-treated over the range from HTT 200°C to HTT 500°C.
    The relation between Knoop hardness number of original coals and rank shows in Fig. 5.The cohesive energy density of coals has a minimum at about 85-90% C. It is supposed, therefore, that the hardness of coals shows a minimum at about 90%C. Although the intermolecular forces tend to increase below about 85%C, the hardness shows a maximum at about 80%C and decreases with the decrease of rank. This phenomenon may be explained by the increase of micro-pore structure or texture in the lower rank coals. On the other hand, the unreactive oxygen has a maximum at about 80%C (Fig. 8). Assu ming that the major part of the unreactive oxygen is an ether-type, it is supposed that the other-type oxygen in coals increases with rank up to about 80%C. It may be said, therefore, that the oxygen bridge in coals increases and the hardness of coals increases with rank in the range of about 70%C to about 80%C.
    The Knoop hardness number of heat-treated non-caking coals below about 80%C is almost the same as that of original coals over the range of HTT about 200-250°C and then increases suddenly with the increase of HTT. It seems that this sudden increase of hardness depends on the chemical change of constitution in original coals caused mainly by dehydration.
    The Knoop hardness number of heat-treated caking coals in the range of about 80% C to about 90%C is almost the same as that of original coals up to HTT about 300°C, gradually decreases with the increase of HTT, reaches a minimum at HTT about 400-450°C, and then suddenly increases with HTT. It is seen that the Knoop hardness of heat-treated caking coals is closely related to the lower molecular substances in original coals and to the thermal softening and thermal fusing properties of original coals.
    The Knoop hardness number of heat-treated anthracite above about 90%C is almost the same as that of original coal up to HTT about 450°C and then increases with HTT. It is suggested that the sudden increase of Knoop hardness in heat-treated coals above a certain HTT depending on the rank of original coals has an intimate relation with the development of cross-linking, aromaticity and ring condensation in heat-treated coals.
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  • Supplementary Experiment of Coking Procedure with Regard to the Effects of Ultrasonic Wave
    Ryohei Takahashi, Kenjiro Takeshita, Takeshi Tsunemoto
    1966 Volume 45 Issue 12 Pages 892-897
    Published: December 20, 1966
    Released on J-STAGE: June 28, 2010
    JOURNAL FREE ACCESS
    In the previous reports, the effects of ultrasonic wave in coking procedure and it's adaptability for improvement on the natures of coke were commented in detail, but several problems, with which we met in the preceding experiments, have not yet been completely resolved.
    In order to make clearer the effects of ultrasonic wave in coking process and to explain the problems remained unaccounted for, a series of experiments are supplementarily carried out, using starch-paste and canada-balsam as the test materials.
    The frequency and the introducing way of ultrasonic wave applied in the present experiment are also different from these in the last ones.
    From the results obtained, we come to the presumption that the alternative layers of thick and thin wall in coke may take place simultaneousely, also that the ultrasonic wave may promote the orientation of graphite-crystallite as melted coal consolidates.
    In this way, the effects of the ultrasonic wave in carbonization of coal become more perspicuous, but since suitable selection of it's frequency or power to be applied must be decided according to the nature of coal, further experiments using different kinds of coal are needed, untill more available results are obtained.
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  • Yuji Yoshida
    1966 Volume 45 Issue 12 Pages 898-905
    Published: December 20, 1966
    Released on J-STAGE: February 23, 2011
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    Prior to researches on semi-industrial scale at the Coal Mining Research Center, fundamental studies on the effects of preheating were carried out at the Resources Research Institute. In this paper, the author summarized the results of the studies.
    According to the experimental results, preheating makes it possible to blend indigenous non-or feebly caking coal to some extent with normal oven charge without reducing coke strength. Non caking coal can not be blended so much as feebly caking one. Permissible amount of these coals also depends on the composition of oven charge itself. Medium volatile coking coal and high volatile coal high in fluidity have the capacity to hold non caking coal to a greater extent.
    Coals are divided into three groups from the view point of preheating effects. For the first group which contains feebly caking and weakly caking coal of low fluidity, the adequate temperatures of preheating and hot charging are up to 300°C, and the lower the rank of coal is, the higher the adequate temperature becomes. Properties of coals preheated to this temperature show little change, except significant decrease in moisture holding capacity measured at 20°C, relative humidity of 76 per cent. The effects of hot charging on these coals, may therefore, be mainly due to increases in bulk density of the charge and in heating rate.
    Weakly caking coal of high fluidity shows quite different behaviours. Strength of its coke reaches a maximum at the preheating temperature of 400°C. In addition, it increoses even if preheated charge is coked after being cooled. Furthermore, effects of preheating are accelerated in the presence of oxygen. The cause of these phenomena is evidently due to chemical changes occured in preheated coal. Excess amount of caking constituents such as pyridine and chloroform extracts are reduced, thus fluidity is properly regulated. As the volatile matter content is decreased, the rate of devolatilization at a solidification point decreases. Fissure formation in coke will therefore, be reduced. DTA-and DTG curves also become similor to those of strongly coking coals.
    The third group consisting of strongly coking coals show only negative preheating effects on the strength of coke.
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  • Yuzo Tada
    1966 Volume 45 Issue 12 Pages 906-912
    Published: December 20, 1966
    Released on J-STAGE: June 28, 2010
    JOURNAL FREE ACCESS
    Surface areas of cokes including blast furnace use, foundry use and general use were measured by adsorption method using carbon dioxide (195°K), methanol (298°K) and nitrogen (77°K) as adsorbates.
    Surface areas obtained from carbon dioxide, methanol, and nitrogen were 1-57 m2/g, 0.8-6.5m2/g, and 0.3-2.1m2/g respectively.
    Surface areas from carbon dioxide were closely correlative with moisture contents of cokes and specific volumes of cokes measured by using water as replaceing agent.
    It was seen considerable agreement between the surface areas from carbon dioxide and those from the adsorption isotherms of water, which were obtained from moisture contents of cokes at various humidity of atmosphere, using Kelvin's equation.
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  • 1966 Volume 45 Issue 12 Pages 918-923
    Published: December 20, 1966
    Released on J-STAGE: June 28, 2010
    JOURNAL FREE ACCESS
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