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Volume 65, Issue 2
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[in Japanese]1986 Volume 65 Issue 2 Pages 85
Published: February 20, 1986
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (1961K) -
Shozaburo SAITO1986 Volume 65 Issue 2 Pages 86-99
Published: February 20, 1986
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSThe applications of supercritical gas extraction are reviewed for refining, deashing and deasphalting of coal and coal derived liquids. After the prin-ciples and characteristics of supercritical gas extraction are stated, it is shown how the extraction yield and the features of extracts and/or raffinates are affected by the extraction conditions (extraction temperature and pressure, coal type and solvent type).
The extraction yield of coal becomes larger as the H/C value of coal, hydrogen donor ability of the solvent, extraction temperature and pressure increase. Temperature is considered to be the most effective factor for increasing extraction yield from flow type experimental studies.The efficiency of deashing and deasphalting of coal derived liquids is affected mainly by the extraction temperature and changes drastically near the critical temperature of solvent.
Supercritical gas extraction offers considerable potential as an alternative to con-version processing of coal and coal derived liquids.View full abstractDownload PDF (1711K) -
Chikatoshi KURATA, Ken-ichi FUJII1986 Volume 65 Issue 2 Pages 100-108
Published: February 20, 1986
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSThe development of CWM preparation process is now at the stage of practical use, and combustion tests and demonstration tests using commercial boilers are began to get the experience for commercial application.
Judging from the CWM composition, the combustion process of CWM is considered basically similar to that of pulverized coal (PC). Then we performed a comparative combustion test with CWM and PC prepared from the same parent coal. As a result, it is become clear that CWM shows the following characteristics compared with PC.
(a) The flame temperature in the furnace is lower by about 100°C.
(b) Emissions of NO and CO are somewhat low.
(c) Unburned carbon content in fly ash is slightly higher than pulverized coal, but it is very lower than predicted value due to the some combustion promotive effect.
(d) Atomizing performance is very important to prevent the formation of large scale droplet which is apt to make a agglomerate particles.
In foreign countries such as USA, Canada, Sweden and so on, many demonstration programs using commercial boilers have been carried out to confirm the availability of CWM as a alternative fuel to a oil fired boiler.
Details of these experiences are reported at the International Symposium on Coal Slurry Fuels Preparation and Utilization held in USA annually.
Summary of them are introduced in this paper.View full abstractDownload PDF (1284K) -
Coloration and Compatibility of Raw Coal-Derived Liquid and Hydrotreated OilsKoji UKEGAWA, Akimitsu MATSUMURA, Etsuro NAKAMURA, Yoshio KAMIYA, Etsu ...1986 Volume 65 Issue 2 Pages 109-115
Published: February 20, 1986
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSColoration and compatibility with commercial gas oil have been studied on raw coal-derived liquid and three kinds of hydrotreated oils. Following results have been obtained:
(1) Irradiation of coal-derived liquid accelerated coloration significantly.
(2) Oxidation of coal-derived liquid caused coloration. High boiling range fraction showed stronger coloration than low boiling range fraction.
(3) The extent of coloration correlated well with the content of nitrogen in oils.
(4) Hydrotreating of coal-derived liquid improved color stability.
(5) The coal-derived liquid suppressed the oxidation of a-methylstyrene and reac-ted with galvinoxyl, the extent being more significant for liquid with higher nitrogen content.
(6) Compatibility of raw coal-derived liquid with commercial gas oil was deterio-rated by oxidation.View full abstractDownload PDF (1023K) -
Kunihiro KITANO, Jun-ichi KAWABATA, Shohei TAKEDA, Midori YUMIYAMA, Yo ...1986 Volume 65 Issue 2 Pages 117-122
Published: February 20, 1986
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSTar yielded in a fluidized bed coal gasifier was analyzed. Taiheiyo coal of size 0.64 and 1.00mm was fed continuously to a 0.083 m diameter fluidized bed and gasified using mixtures of steam and air.
Tar Quantity in produced gas decreased rapidly as the bed temperature became higher. Molecular weight of tar became smaller and ratio of methane and ethane in produced gas increased at higher temperature. Tar yield decreased as the tempera-ture of freeboard region just above the bed became higher. But the gas residence time in freeboard region had no effects upon tar yield.View full abstractDownload PDF (577K) -
Toshimitsu SUZUKI, Masaru MISHIMA, Iwao ANZAI, Akihiro YAMAUCHI, Yoshi ...1986 Volume 65 Issue 2 Pages 123-130
Published: February 20, 1986
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSThe catalytic steam gasification of eleven different rank coals was carried out using sodium hydridotetracarbonylferrate (Na [HFe (CO) 4]) (Na: 0.68-2.05 wt%, Fe: 1.67-5.0wt%) as a catalyst in order to investigate characteristics of the catalyst. Reactions were conducted in a semi flow type fixed bed reactor or in a thermobalance under a steam argon atmosphere at 700-850°C.
Steam gasification of all the coal used were significantly enhanced by impreg-nating the ferrate to coal.
The profile of the gasification rate against carbon burn-off for catalyzed runs differs considerably by the coal used, when small amount of the catalyst was loaded. With increasing the amount of the ferrate, the initial rate of gasification was elevated and the profile of the rate against burn-off drastically changes from the pattern that the rate of gasification decreased with an increase in burn-off to the opposite pattern that gasification rate increases with an increase in burn-off. Similar tendency was observed when reaction temperature was elevated at the lower catalyst level.
The coal with the ferrate was treated under argon at 800t for 60 min and then gasified by steam. The gasification rate decreased in comparison with the non-treated coal wtih the same catalyst.
When a selected coal was deashed and loaded with the ferrate, gasification profile changed into the pattern that show great increase in the gasification rate with an increase in burn-off.
These results showed that the gasification rate was lowered by deactivation of the catalyst with ash in coal, deactivation of coal char at higher temperature, and the evaporation of alkali metal from coal char surface, during steam char reaction.View full abstractDownload PDF (984K) -
Senji HONMA, Yoneshiro TAZAKI, Midori YUMIYAMA, Jun-ichi KAWABATA, Shi ...1986 Volume 65 Issue 2 Pages 131-135
Published: February 20, 1986
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSAs an effective utilization of coal ash generated from coal power station, production of citrate-soluble potassium silicate fertilizer were studied experi-mentally using fluidized bed.
The fly ash discharged from electric dust-collector was the main raw material for the fertilizer, and it was mixed with caustic potash and potassium carbonate and others. Pulverized coal of approximately 10wt% was added to the raw materials, mixed up sufficiently and granulated -2mm in diameter with a pelletizer. The granular raw material were fed into a fluidized bed reactor and baked up to the fertilizer at 850°C to 1100°C. In this process, the heat of combustion of added coal was supplied as a heat required to baking process. Mean residence time of particles in the reac-tor, which effects to the quality of the fertilizer, was controlled by coal content in the raw materials.
Based on the present baking process, a commercial plant of production of the fertilizer was constructed and has been operated in Japan.View full abstractDownload PDF (615K) -
Masayuki HORIO, Mayumi HOSHIBA, Fujio FUNAZAKI, Nobuetsu YUTANI, Naosh ...1986 Volume 65 Issue 2 Pages 136-142
Published: February 20, 1986
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSIn order to improve the properties of highly loaded Coal-Water-Slurry (CWS), experiment was conducted concerning the properties of gas containing CWS, which is named CGWS (Coal-Gas-Water-Slurry) in this paper. Ground Miike coal, water and additives were mixed to make coal water slurry of 62-68wt% coal con-centration. To prepare CGWS CO2 was dissolved into CWS by pressure elevation (303kPa) and then the pressure was decreased to foam the slurry. Unstable bubbles were killed by mixing in a ball mill. The properties of CGWS, i.e., apparent viscos-ity, expansion characteristics and storage stability, were compared with those of CWS of corresponding coal and additive concentrations.
It was found that the bubble killed CGWS has almost the same apparent viscosity as that of the corresponding CWS. Since the interstitial water of CGWS was saturated with CO2, the volume of CGWS remarkably increased with increased temperature or decreased pressure due to the degassing and foaming. Foamed (non-killed) CGWS showed good stability during storage. The bubbles of foamed CGWS were easily killed in the shear field.View full abstractDownload PDF (962K) -
Toshinori KOJIMA, Takehiko FURUSAWA1986 Volume 65 Issue 2 Pages 143-149
Published: February 20, 1986
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSCoal with high ash content of 37.8% produced in Hokkaido was pulverized, sieved to smaller than 297 pm, and separated into a number of fractions with different ash content by the sink-float separation. The contents of 28 elements in the sink-float separates and the original coal were analyzed by use of a X-ray microanalyzer and a ICP emission spectral analyzer. The organic affinity index was defined and determined from the analytical results for each element.
The main elements, Si, Al, Fe, Ca, K, Na and Mg were almost uniformly dis-tributed in the ash, however, Ti showed strong organic affinity. In the minor and trace elements, only Mn showed weak affinity for inorganic matter. The elements, Pb, Mo, La and Cd showed weak organic affinities and the other elements, Ba, Sn, Cr, Ni, Sc, Y, Be, Co, Cu, Zn, Zr, As showed moderate or strong and V, Sr, B showed quite strong affinities. These results well agreed with the previously reported results for coals with low ash contents.
These results indicate that most trace or minor elements, some of which are suggested to be harmful to plants, domestic animals and/or human beeings, could hardly be removed from organic matter by the deashing processes of coal.View full abstractDownload PDF (1012K)
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