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Volume 63, Issue 6
Displaying 1-9 of 9 articles from this issue
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[in Japanese]1984 Volume 63 Issue 6 Pages 361
Published: June 20, 1984
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (229K) -
Yasuo WADA1984 Volume 63 Issue 6 Pages 362-370
Published: June 20, 1984
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSMost of coal ash produced in the coal thermal power stations in Japan has been disposed for landfilling on the land and in the sea. However, in the near future, it is anticipated that newly built power stations will face the sevier problems of the coal ash disposal because of the deficient spaces for disposal. On the other hand, it is apparent that there will be a shortage of the natural resources for construction, for example, limestones, clays, aggregates and sonds. Therefore, if the coal ash is effectively utilized for the construction material, the problem of the coal ash disposal in the power stations will be solved.
In some countries, the technology of the coal ash utilization has been developed, and in fact, the coal ash produced from the power stations are successfully used for the cement manufacturing and also for the concrete replacing. In this paper, the author illustrated some examples of the successful utilization of the coal ash and pointed out some problems to be solved in Japan. It is necessary to establish and develop the technology for coal ash utilization, which includes the upgrading of coal ash based on the economical advantage of the final products.View full abstractDownload PDF (1396K) -
Effects of Pressure, Temperature, Catalyst Addition, Kinds of Solvents and Gas Atmosphere on Coal ConversionSatoshi OHSHIMA, Motoo YUMURA, Kazuo SHIMADA, Morio SUZUKI, Toshiichi ...1984 Volume 63 Issue 6 Pages 371-379
Published: June 20, 1984
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSEffects of pressures, temperatures, catalyst addition, and kinds of solvents and atmospheric gases on coal liquefaction of Taiheiyo coal were examined using a c. s. t. reactor and the following conclusions were obtained.
1. The experimental results were correlated by the following rate equation 1-X=X/ (kθ) +α where the value of α was affected only by temperature, and the value of k varried with reaction conditions.
2. A coal liquefaction mechanism was estimated to involve the following two steps; (1) thermal cracking of coal and intermediates, and stabilization of them by hydrogen donor components which was a noncatalytic liquid-liquid reaction, (2) reproduction of the donor components by gaseous hydrogen which was a gasliquid catalytic reaction, and it was found that the rate determining step of coal liquefaction was considerably affected by the amount of donor components.
By this reaction mechanism, effects of pressures, kinds of solvents and catalyst addition on coal liquefaction observed in the present experiment and also those found in literatures could be reasonably explained.View full abstractDownload PDF (1067K) -
Hiroshi NAGAISHI, Hiroaki KONISHI, Hiroshi MORITOMI, Yuzo SANADA, Tada ...1984 Volume 63 Issue 6 Pages 380-386
Published: June 20, 1984
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSEffects of iron compounds, sulfur and hydrogen sulfide on coal liquefaction were experimentally examined. The liquefaction was performed in a 55cm3 micro-autoclave under hydrogen and/or hydrogen sulfide atmospheres at 723K using naphthalene as solvent and red-mud, sulfur, iron (III) oxide, and iron disulfide as catalyst.
It was shown that in naphthalene/hydrogen system catalytic activity of iron (III) oxide was higher than that of sulfur and was equal to that of iron disulfide. In the presence of iron (III) oxide the yield of pyridine solubles increased about 10wt.% by an addition of sulfur or hydrogen sulfide. However, the addition did not change the yield at all when iron disulfide was employed instead of iron (III) oxide. Hence, effects of mineral matter in coal on liquefaction characteristics were concluded to depend strongly on iron content. In addition, sulfur and hydrogen sulfide were shown to have contribution to transfer of gaseous hydrogen to coal via solvent as iron (III) oxide was sulfided.View full abstractDownload PDF (765K) -
Isao MOCHIDA, Takaaki SHIMOHARA1984 Volume 63 Issue 6 Pages 387-396
Published: June 20, 1984
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSCocarbonization properties of some coals with petroleum derived pitches (A240 or HA240) were examined after their preheat treatment at 200-400°C to reveal the reactivities of coals in the precarbonization and its influences on their cocarbonization susceptibilities against the additive. When two paticular coals of Zontag Vlei and Metla of the similar rank, the susceptibility of the former coal being much higher than that of the latter without any pretreatment were compared, the latter coal lost its susceptibility at much lower temperature than the former, although both coals did completely at 410°C where the respective chars were produced.
The pretreatment such as de-mineralization and o-alkylation, which had been found effective to improve the cocarbonization susceptibility of the latter coal, increased markedly the stability of its cocarbonization susceptibility against the preheat treatment.
Some other coals exhibited their respective precarbonization, reactivity to deteriorate the susceptibility, the extent of deterioration appearing to correspond to the cocarbonization behavior approximately but not exactly according to their ranking.
An Australian brown coal exhibited interesting behaviors to exhibit better cocarbonization susceptibility in a very limited temperature range of the preheat treatment, where the homogeneity of isotropic appearance of the coke was very much improved, indicating that the coal was dissolved or solvolyzed better in the additives after the preheat treatment.
Some analytical studies on the preheat treated coals, evolved gases and weight decrease during the preheat treatment suggest that the reactivities of oxygen functionality are related to the above behaviors. Its higher condensation reactivity tends to lead to the deterioration of cocarbonization susceptibility, however the adequate removal of oxygen functionalities in the brown coal by the preheat treatment improves its cocarbonization susceptibility probably due to the decarboxylation.View full abstractDownload PDF (2338K) -
Mitsuhiro SAKAWA, Yoshihisa SAKURAI, Yukiaki HARA, Yasuto SHIMOMURA, M ...1984 Volume 63 Issue 6 Pages 397-402
Published: June 20, 1984
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSRecently, the quality of metallurgical coke has been evaluated not only by strength at room temperature, such as the drum index, but also by high-temperature properties.
The coke strength after CO2 gasification (reaction) (CSR) is one of the evaluation methods of coke for high-temperature properties. The authors have been trying to estimate the value of CSR by studying properties of coal.
In this work, coke from coal and coal blends with different properties is prepared to get the relationship between the properties of coal and the value of CSR.
The estimation method for the value of CSR from the properties of coal such as the reflectance of vitrinite and the amounts of inertinite and ash, especially alkali content, is proposed.
This method is ascertained with the value of CSR of coke produced from a commercial oven.View full abstractDownload PDF (569K) -
Shigeaki KASAOKA, Hiroyuki NANBA1984 Volume 63 Issue 6 Pages 403-412
Published: June 20, 1984
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSThe de activation on a V2O5/TiO2 catalyst with deposited alkaline earth metal salts in the reduction of NO with NH3 and the regneration of the de activated catalyst were investigated. Alkaline earth metal salts (CaSO4, CaCl2, CaCO3, Ca (NO3) 2, MgSO4, MgCl2, MgCO3, Mg (NO3) 2) were deposited on the V2O5/TiO2 catalyst (average diameter 1.0mm) by an impregnation method. Measurements were made in a flowtype packed bed reactor under atmospheric pressure at 350°C, the inlet gas was a mixture of NO (500ppm), SO2 (0, 500ppm), NH3 (500ppm), O2 (5%), H2O (10%), and N2, and the total flow rate was 1000 Ncm3/min (sv: 6×104h-1).
The following results and informations were obtained:
1) In the reduction of NO under the absence of SOx, the degree of de activation was remarkably affected by the kind of salts deposited. The degree of de activation with deposition of chlorides, carbonates and nitrates was large, and that of sulfates was very small.
2) In the reduction of NO under the presence of SOx, the effect of the salts except MgCl2 on the degree of de activation was not almost found.
3) The de activation was mainly caused by the reaction of alkaline earth metal salts with V2O5/TiO2 catalyst, leading to the formation of an inactive oxide complex.
4) The de activated catalyst was not regenerated by a washing procedure with water.View full abstractDownload PDF (1233K) -
Hiromi TAKEUCHI, Akira DEGUCHI, Hideo HOSODA, Toshimasa HIRAMA, Masayu ...1984 Volume 63 Issue 6 Pages 413-418
Published: June 20, 1984
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSIt is necessary to reveal the influences of coal and/or coal combustor types on combustion characteristics for effective utilization of coal. Experiments were performed using different types of fluidized bed combustor, i. e., (A) single-bed without secondary air injection, (B) single-bed with secondary air, and (C) dual-bed. The combustible components in carryover ash and emission levels of carbon monoxide and nitrogen oxides were measured for four different coal types. The results show that these values are different in coal type and the combustion efficiency is relatively high using the coal of which the fuel ratio is low. The dual-bed combustor has the possibility of an increase in combustion efficiency. From combustion experiments of coal without fine size it is clear that the larger coal size, the higher combustion efficiency.View full abstractDownload PDF (672K) -
Yoshiaki MIURA1984 Volume 63 Issue 6 Pages 419-430
Published: June 20, 1984
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESS“Coke” in a narrow sense means lump of carbonaceous materials from high-temperature carbonization of slack, but this term is also applied in a wide sense to other types of carbonaceous materials differing in raw material and method of manufacture, for example petroleum coke and pitch coke. This report, Part II of four-part series, on coke from coal discusses the relations between physical and chemical structures and properties of practical importance such as mechanical strength and chemical reactivity in the light of two fundamental characteristics of coke, one as porous composite material and the other as carbon material. The properties under review are greatly influenced by four structural factors; pore structure, crack, optically anisotropic texture of cell wall, and co-existing inorganic components.View full abstractDownload PDF (2303K)
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