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Volume 69, Issue 8
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[in Japanese]1990 Volume 69 Issue 8 Pages 683
Published: August 20, 1990
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (1295K) -
Development of HydropyrolysisTohru KAMO, Mistunori MAKINO1990 Volume 69 Issue 8 Pages 684-691
Published: August 20, 1990
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSHydropyrolysis is considered as the third way for coal conversion, because products can be controlled by reaction condition easily. In this paper we describe the recent studies on hydropyrolysis.
A few company have built pilot plants to establish this technology . Product gas is mainly methane. Oil yield and its composition depend on the temperature of pyrolysis. The benzene content of the oil increase with temperature.
It is considered that hydropyrolysis reaction consists of two step mechanism . High hydrogen pressure inhibit devolatilization and increases hydrogenation of the products formed in the first stage of the reaction. At high hydrogen pressure slow heating rate can even give higher total volatile yield than rapid heating . High oil yield is obtained when coal is prehydrogenated or inpregnated with catalyst.
In hydropyrolysis mass transfer, heat transfer and chemical reaction occur simultaneously in very short time. The reaction mechanism is, therefore, so complicated that further investigation from various aspect are required.View full abstractDownload PDF (849K) -
Fuyuki NOGUCHI, Philip Arthur BORRILL1990 Volume 69 Issue 8 Pages 692-696
Published: August 20, 1990
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSCoal Hydrogenation is an advanced, clean technology for the direct conversion of coal into methane and, if required, high value hydrocarbon liquid co-products. Under a Joint Development Agreement, British Gas plc and Osaka Gas Co., Ltd. have developed a novel and highly efficient coal hydrogenator in which the reaction gas is internally recirculated and no oxgen is used. The study of a commercial-scale plant incorporating the novel hydrogenator showed a higher thermal efficiency than competing technologies and good overall economics.View full abstractDownload PDF (548K) -
Iruru TAKAHASHI1990 Volume 69 Issue 8 Pages 697-700
Published: August 20, 1990
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSA flash hydrogasification is of particular interest because it produces methane in a single stage reaction with high efficiency and simultaneously produces aromatic liquids as by-products. This paper describes the flash hydrogasification process proposed by Rockwell International Corporation. The flash hydrogasifier was developed by the application of Rockwell's rocket engine technologies. Using the hydrogasifier, a pulverized coal can be readily gasified with high temperature hydrogen jets to produce methane and benzene. A number of gasification tests were carried out to investigate the hydrogasifier performance in the Advancement of Flash Hydrogasification Program by Rockwell International and the industrial consortium. On the basis of the results, the thermal efficiency of the flash hydrogasification process was estimated at 74%.
The flash hydrogasification will be the key technology and take an important rolein the utilization of coal in the future.View full abstractDownload PDF (475K) -
Tadashi KAI1990 Volume 69 Issue 8 Pages 701-704
Published: August 20, 1990
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSCatalytic flash hydropyrolysis on Australian brown coal had been developed to get product yield with BTX rich product and ethane rich gas product.
Catalyst research were done using 0.1 grams batch reactor and 3 kg/h bench unit.
By using coal impregnated with catalyst selected from the group consisting of halides, sulfates, nitrates, hydroxides or oxides of the metal elements selected from the group consisting of Fe, Co and Ni, product yield with BTX yield of 23% (carbon conversion) were obtained under the reaction condition of 650-800°C (zone controlled) and 70kg/cm2G.
70 hours continuous operation were successfully done using 0.5t/day process development unit.
Lock hopper system for coal charge and char discharge were smoothly in action and no plugging trouble were met in entrained reactor tube of 2 inches and 7 meter height.
R & D were stopped in 1984.View full abstractDownload PDF (451K) -
Mamoru KAIHO1990 Volume 69 Issue 8 Pages 705-710
Published: August 20, 1990
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSIn order to appreciate the hydrogasification process, its cold gas efficiency was compaired with that of methanation process. It was concluded that the efficiency of hydrogasification was better than that of methanation because the oxygen ratio employed in former process was lower than that of latter one.
The heat of reactions between carbon and hydrogen to form methane and BTX were examined theoretically. It was considered that the heat would be insufficient to keep the temperature of practical reactor in adequate level when coal was gasified with excess hydrogen. Some methods to supply heat to gasifier were proposed and their technical problems were discussed.View full abstractDownload PDF (706K) -
Jun-ichiro HAYASHI, Katsuki KUSAKABE, Shigeharu MOROOKA1990 Volume 69 Issue 8 Pages 711-714
Published: August 20, 1990
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSRecently statistical models of flash pyrolysis based on the macromolecular coal structure have been proposed. While traditional models based on lumping kinetics have little flexibility for the variety of coal ranks and reaction conditions, statistical models can predict the variation of tar yield and molecular weight with pressure and heating rate. However, the relation among the coal structure and chemical reactions (degradation and crosslinking reaction) is not fully understood. Advanced pyrolysis models which provide enough information to control pyrolysis reaction of coal should be created in near future.View full abstractDownload PDF (471K) -
Mitsuhiro SAKAWA, Kouichi IKEDA, Takafumi KAWAMURA, Hiroyuki KOZURU, K ...1990 Volume 69 Issue 8 Pages 715-720
Published: August 20, 1990
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSCoal flash pyrolysis is one of the most interesting future coal utilization technology, because the flash pyrolysis has tendency to volatilize more coal substance than that from conventional slow heating.
Coal pyrolysis has been studied under various conditions by high pressure thermogravimetry and estimation model of products from coal pyrolysis.
Authers proposed the conditions of coal pyrolysis from controlling products and economic points.
Small scale reacters with these conditions have been constructed for getting basic and engineering data of the pilot plant.View full abstractDownload PDF (1778K) -
Kouichi MIURA, Kazuhiro MAE, Kenji HASHIMOTO1990 Volume 69 Issue 8 Pages 721-725
Published: August 20, 1990
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSA new flash pyrolysis method which drastically increases both total volatile matter and tar yield was introduced. This method intends to effectively transfer radicals from/via solvents to reactive coal fragments. To accomplish such effective radical transfer, the rate of radical formation from the solvent and the formation rate of the coal fragment must be matched. Furthermore, the radical and the coal fragment must be in close contact during the pyrolysis. When the coal is treated with the solvent at 100 to 250°C, the solvent penetrates into the micropores and swells the coal by enlarging the micropores of its molecular dimension, and it is retained intimately within the micropores. Pyrolyzing thus prepared swollen coal, we could increase both the total volatile matter and the tar yield significantly. When an Australian lignite swollen by tetralin was pyrolyzed, the total volatile matter reached 67% and the tar yield surprisingly reached 42%. These great increases were found to be due to a physical effect and the effective radical transfer brought about by the swelling.View full abstractDownload PDF (651K) -
Takuo SUGAWARA1990 Volume 69 Issue 8 Pages 726-730
Published: August 20, 1990
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSThe behavior of a variety of sulfur forms in coal is complicated in the hydropyrolysis prior to hydrogasification. The desulfurization characteristics which relate closely to the development of hydrogasification technology have been sur-veyed by giving attention to the process of change in the sulfur forms in the rapid hyd-ropyrolysis of coal.
The variety of sulfur forms in coal is firstly described by referring to their origin. Experimental results are secondly shown concerning to the behavior of sulfur when steam coals are pyrolyzed under a slow heating condition in a hydrogen stream at nor-mal pressure. A desulfurization model proposed by the author and coworkers has been introduced with some simulated results. Pyritic and organic sulfur forms in solid are interrelated together through hydrogen sulfide in gas phase.
Observed values are thirdly explained kinetically by the model for change in the sulfur-form distribution when coals are hydropyrolyzed rapidly with a heating rate 6×103°C/sec and a terminal temperature 960°C by using a free fall pyrolyzer. Good performance is noted that maximum extent of desulfurization 92% was achieved through the efficient reduction of organic sulfur which is hard to decrease with physic-al desulfurization methods. The desulfurization rate of organic sulfur strongly de-pends on the increase rate of internal surface area accompanied with hydropyrolysis. The difficulty of decomposition of refractory organic sulfur is another factor which de-termines the final extent of desulfurization.View full abstractDownload PDF (604K) -
[in Japanese]1990 Volume 69 Issue 8 Pages 731
Published: August 20, 1990
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (134K) -
Kiyoshi OHARA, Yoichi JINJA1990 Volume 69 Issue 8 Pages 732-740
Published: August 20, 1990
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSMean-diameters (SMD) of CWM-spray which made under various testing conditions were measured. These values are plotted on the diagram of In (SMD-30) vs V (Vis velocity of atomizing air), then SMD are arranged nearly on each straight line of CWM-type. In order to explain this behavier, SMD values are arranged on the diagram of in (SMD-30) vs V for each condition (viscosity, coal size, QW etc.), and are recurred by V, viscosity, coal size, QW etc.
As the result of this procedure, it become to light that SMD can be explained as a function of these parameters, i. e.
ln (SMD-30) = (a1μ+a2R+a3QW) V+b
here μ, R and QW are viscosity, coal size, CWM flow rate, and a1, a2, a3 and b are constant. This function is checked by statistics, then it is believed that the parameters are appropriate as factors giving influence to SMD of CWM-spray.View full abstractDownload PDF (957K) -
Toshinori KOJIMA, Koichi TANAKA1990 Volume 69 Issue 8 Pages 741-751
Published: August 20, 1990
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSThe optimum operation temperature of coal gasifier is considered to be about 1300°C from various view points. In the present study, the temperature profiles in a batch experimental fluidized bed coal gasifier were measured. Flat and cone shaped gas distributors for steam introduction with 3mm and 6mm i.d. nozzles for air introduction were employed. The effects of the grid structure on the tempera-ture profile in the grid zone and on the produced gas composition from the experimental gasifier were discussed.
An obvious jet-shape and restricted high temperature area was observed without any clinkers, when air was introduced from a nozzle with small diameter (3mm i.d.) and steam from cone type distributor, while the high temperature area spread over the cross sectional area of the bed when the air was introduced from 6mm i.d. nozzle and steam from flat plate. The consumption rate of carbon and the evolution rate of carbon monoxide were extremely high and the production of carbon dioxide was suppressed at relatively low conversion in the former case while the increases in the combustion rate of produced hydrogen and the ratio of production of carbon dioxide to that of carbon dioxide were observed in the latter case. The relatively high temperature operation with favorable produced gas composition was suggested to be possible by employment of suitable grid structure to increase the circulation rate of carbon.View full abstractDownload PDF (1226K) -
Effect of Coal Nature on Intrinsic Reaction RateShohei TAKEDA, Senji HONMA, Yonesiro TAZAKI, Midori YUMIYAMA, J.W. SHI ...1990 Volume 69 Issue 8 Pages 752-758
Published: August 20, 1990
Released on J-STAGE: October 21, 2011
JOURNAL FREE ACCESSSteam gasification of 13 kinds of coal char was carried out at temperatures of 1073-1273K and under total pressures of 0.4-1.6MPa by a high pressure tubular cell reactor. The surface area and the carbon structure of the reaction residue were determined at various char conversions up to about 0.90.
The main component in the product gas was hydrogen, which amounted to about 50-60% of the total product gas for each char employed. The sum of CO and CO2 were nearly 40-50%. The ratio of CO to CO2 varied with the coal rank. The rate of CO2 formation was larger for the lower rank coals, whereas that of CO formation was larger for the higher rank coals. For each char, contribution of CO shift reaction to carbon-steam reaction, evaluated the mole ratio of H2 formation to (CO+CO2) formation, varied with the carbon conversion.
The surface area of the reaction residue increased rapidly at the early stage of the reaction and then decreased after showing a maximum. The maximum values depended upon the kind of coal char. The surface area was found to be independent of the total pressure or of the reaction temperature at a certain conversion level.
The instantaneous rate based on the unit surface area was very small at the initial and the final stages of the reaction. The (002) peak due to graphite structure, which had been detected for gasification by CO2 and H2, was seen in the X-ray diffraction spectra for reaction residues in the present experiment. The formation of graphite structure corresponded to the decrease of instantaneous rate at the final stage of the reaction.View full abstractDownload PDF (797K) -
[in Japanese]1990 Volume 69 Issue 8 Pages 759-763
Published: August 20, 1990
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (550K) -
[in Japanese]1990 Volume 69 Issue 8 Pages 764-768
Published: August 20, 1990
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (591K) -
[in Japanese]1990 Volume 69 Issue 8 Pages 772
Published: August 20, 1990
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (127K) -
[in Japanese]1990 Volume 69 Issue 8 Pages 773
Published: August 20, 1990
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (128K)
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