Special Issue
Structural Analyses of Coal and New Conversion Technologies
Reviews
Recent studies on coal structure
Osamu YAMADA(Gasification Div., Energy Resources Dept., NIRE)
Abstract
Coal is a complex mixture of organic and inorganic materials and traditionally known to consist of solvent soluble "immobile component" and solvent soluble "mobile component" . This concept is called two phase model and based on the idea that coal is a three dimensionally cross-linked macromolecular network. Molecular structure of coal and various coal conversion reactions have been discussed using this model. Recent studies on coal structure indicate the importance of non-covalent interactions in coal. Associated model for coal structure has been proposed. Surface reactivity of coal is conventionally accounted for a rigid interconnected micropore network system. According to the results of recent studies, pore structure of coal is claimed to consist of separate closed pores. Small angle neutron scattering studies indicate no micropore structure in coal. Novel approaches to the problems exist in the traditionally approved concepts of coal structure were reviewed.
Key Words : Coal, Chemical structure, Polymeric structure, Pore structure
(Language:Japanese)
Recent Trends of Development of Coal Gasification
Mamoru KAIHO(Energy Resources Dept., NIRE)
Abstract
To put a gasification process on a commercial basis, the capacity of gasifire has been increased remarkably in recent years and average size of one under developing goes up to over 2000t/d. Most people participating in the development have only been concerned about whether such a large plant will be operated stably or not. However, it seems reasonable that the technology will refine to improve the efficiency and running costs from the chemical viewpoint after mechanical problems to scale up the plant have been solved. Here, the recent tendency of the development of gasifire was reviewed, focussing on the chemical issue of the coal gasifing process.
Key Words : Coal, Gasification, Efficiency
(Language:Japanese)
Progress of Coal Liquefaction Technology
Ikuo SAITO(Heteroatoms Div., Energy Resources Dept., NIRE)
Abstract
Recent progress of coal liquefaction technology as well as the history of its development has been reviewed. Pilot plant scale operations were carried out in Germany, England, USA and Japan in the 1940's (first generation technology). The situation of these pilot plant operations are briefly referred to. From the mid 1960's, coal liquefaction came under attention again due to the tight situation of petroleum production. New coal liquefaction technologies such as EDS, H-coal, SRC, New IG processes and so on(second generation technology) and advanced coal liquefaction technologies such as Close-Coupled Integrated Two Stage Liquefaction(CC-ITSL), Brown Coal Liquefaction(BCL) and NEDOL processes(third generation technology) are overviewed and the future direction of research and development of coal liquefaction is studied.
Key Words : Coal liquefaction, Research and development, History and progress
(Language:Japanese)
For Effective Use of the Newest NMR
Keiji Miki(Hydrocarbon Research Div., Energy Resources Dept., NIRE)
Abstract
A new NMR spectrometer (JEOL CMX300) has been introduced into our Institute. Its superior ability should work as a powerful tool for analyzing non-crystallized materials. The article is described about the information obtained from the equipment and methods of measurements available in order to use this apparatus effectively.
Key Word : NMR
(Language:Japanese)
A PLIF -Planar Laser Induced Fluorescence- System for a Visualization of Temperature and Concentration Fields in Gas Phase
Masao TAKEUCHI(Advanced Combustion Systems Div., Thermal Energy and Combustion Engineering Dept., NIRE)
Abstract
This paper describes a brief introduction of a PLIF measurement system set up in NIRE recently. PLIF is the short form for a planar laser induced fluorescence method, which is the measurement technique for the acquisition of instantaneous distribution of temperature and radicals in high temperature reacting flow fields such as combustion, using a high power ultraviolet laser beam. NIRE's system with a high power narrow band excimer laser and two intensified CCD cameras, is able to conduct many other measurements such as temperature distribution by Rayleigh scattering, majority species concentration and temperature by Raman scattering and flow velocity by Mie scattering. Simultaneous measurements of the quantitative OH radical concentration and temperature or the two different radicals are also possible. The visualization of OH field in homogeneous reaction near the combustion catalyst wall and the analysis of NOx formation reactions near the char wall are in progress.
Key words : PLIF, Excimer laser, Visualization, Concentration measurement, Temperature measurement
(Language:Japanese)
Original Papers
Sorption of Methanol on Coal
Hajime YASUDA, Mamoru KAIHO, Osamu YAMADA,
Yasushi SONEDA, Mitsuo KOBAYASHI and Mitsunori MAKINO
(Gasification Div., Energy Resources Dept., NIRE)
Abstract
The sorption of methanol vapor on air oxidized Taiheiyo coal was investigated by repeated sorption and desorption at 25.0° C The sets of sorption and desorption were repeated under the same conditions 3 or 4 times, then methanol was supplied raising the amount for the next run. The experiments were repeated under the same conditions 3 or 4 times again. The amount of methanol supplied was raised for the sets of next sorption experiments. Sorption data were analyzed using the BET adsorption isotherm to get the index parameter (Wm) corresponding to the amount of methanol sorbed as filling monomolecular layer. It was found that Wm for the nth run was increased with an increase in the amount of the methanol sorbed for the (n-1)the run. The sorption isotherms changed in the direction of the increase in Wm only after the amount of methanol sorbed was increased.
Key Words : methanol, sorption, BET
(Language:Japanese)
Solid State 13C CP/MAS NMR Study of Changes in Coal Structure after Rapid Heating
Hiroyuki KAWASHIMA(Fundamental Research Div., Energy Resources Dept., NIRE)
Yasumasa YAMASHITA(Energy Resources Dept., NIRE)
Atsushi INABA(Fundamental Research Div., Energy Resources Dept., NIRE)
Abstract
In the present study, Akabira coal was heat-treated at 3K/min or 100K/min at 723K under nitrogen flow and then changes in coal structure were examined by solid state 13C NMR. At 100K/min, the char contained more CH2 and CH group carbon with low fa compared to the heating rate of 3K/min. Char produced at 100K/min showed lower fa not only since more THFS was present but because the THFI structure itself was more aliphatic than at 3K/min. At 100K/min, thermal plasticity and greater coke strength were noted, owing to increased THFS in the char. For the char produced at 100K/min, the molecular mobility of the aliphatic carbon moiety was greater than at 3K/min. Increase in this molecular mobility and THFS with heating rate may possibly have been due to enhanced thermal plasticity.
Key Words : Coal structure, Solid state 13C-NMR, Heating rate, Thermal plasticity
(Language:Japanese)
Catalytic solubilization of coal and behavior of oxygen containing functional group in the presence of trifluoromethanesulphonic acid
Kiyoyuki Shimizu (Heteroatoms Div., Energy Resources Dept., NIRE.)
Yoshihiro Iwami (Faculty of Material Science, Japan Advanced Institute of Science and Technology, Hokkuriku)
Ikuo Saito (Heteroatoms Div., Energy Resources Dept., NIRE.)
Hironori Karamatsu (Faculty of Science and Technology, Science University of Tokyo.)
Akira Suganuma (Faculty of Science and Technology, Science University of Tokyo.)
Abstract
Trifluoromethanesulfonic acid (TFMS) was found to solubilize lignite (Yallourn coal) and subbitumi-nous coal (Taiheiyo coal) in the presense of isopentane at 150° C for three hours at autogeneous pressure of 6.1-6.9 MPa without hydrogen. Yallourn coal gave 63wt% pyridine soluble fraction in this reaction, and additional TFMS was required to attain maximum solubility. However, the treated Taiheiyo coal could be solubilized in pyridine by 90% by the same reaction withTFMS. This solubilization would not be adequate since the lignite has many oxygen containing functional groups. The lower solubility of the treated lignite, Yallourn coal, may be ascribed to the greater number of phenolic groups. TFMS is essential for the depolymerization of coal molecules in Yallourn coal solubilization, and accelerates alkylation and hydrogenation in Taiheiyo coal solubilization. The activity of TFMS as an acid catalyst may possibly lessen by interaction with oxygen functional groups and water was
produced by cleavage of aliphatic ether groups and dehydration of phenolic OH groups.
Key Words : Coal solubilization, Superacid, Lignite, Oxygen Containing Functional Groups
(Language:Japanese)
Reaction of Hydrogen Atom with Coal Model Compounds
Tohru Kamo (Hydrocarbon Research Div., Energy Resources Dept., NIRE)
Abstract
Reactions of hydrogen atom with diphenylmethane, diphenylether, and diphenylsulfide were carried out by using fast flow discharge reactor at 25° C-580° C under 530 Pa of helium as a balance gas. Hydrogenated diphenylmethane was produced mainly from diphenylmethane at 25° C. Benzene, cyclohexene, cyclohexane, toluene, and cyclohexane were observed as products from hydrogenolysis of diphenylmethane. The yields of products from hydrogenolysis increased with reaction temperature. Hydrogenated diphenylether, phenol, cyclohexanol, and hydrogenated diphenylsulfide, benzenethiol, cyclohexanethiol were produced from diphenylether and diphenylsulfide respectively. The total yield of products for hydrogenolysis of diphenylsulfide was higher than that for diphenylmethane and diphenylether.
RRKM unimolecular reaction theory indicates that the chemically activated radicals produced from the addition of hydrogen atom at the ipso position of feed molecules almost decomposed. On the other hand, the radicals produced from the addition of hydrogen atom at the aromatic rings were converted to hydrogenated feed molecule. The ratios of the addition rate of hydrogen atom at the ipso position to that at the aromatic rings were 0.05, 0.41, and 1.11 for diphenylmethane, diphenylether, and diphenylsulfide respectively.
Key Words :Diphenylmethane, Diphenylether, Diphenylsulfide, Hydrogen atom, Chemical activation, Addition of hydrogen atom
(Language:Japanese)
Effects of Heating Rate on Coal Carbonization (II)
Yasumasa YAMASHITA (Energy Resources Dept., NIRE.)
Atsushi INABA (Fundamental Research Div., Energy Resources Dept., NIRE)
Hiroyuki KAWASHIMA (Fundamental Research Div., Energy Resources Dept., NIRE)
Ikuo SAITO (Heteroatoms Div., Energy Resoureces Dept., NIRE)
Abstract
The thermal degradation mechanisms of Akabira and Miike coals were studied in an atmosphere of nitrogen by thermogravimetry in which two different heating rates (3° C or 100° C/min) were employed. Properties of product chars were measured by ultimate analysis and IR. Amounts of THF solubles of produced char and their molecular distributions were also measured. When heated at 100/min the structures of THF solubles, being produced by thermal degradation and maintained in product char, were similar to raw coal .
Experimental results at heating rate of 3° C/min, however, show that THF solubles were decomposed more to gas and tar and also produced high condensed carbon materials.
Key Word : Coal Carbonization
(Language:Japanese)
Coal Crushing and Pore Formation by Steam-Explosion
Yoshio YAMADA (Carbon Materials Div., Energy Resources Dept., NIRE)
Takeshi FURUTA (Carbon Materials Div., Energy Resources Dept., NIRE)
Minoru SHIRAISHI (Chief Senior Researcher)
Seiji OHARA (Forestry and Forest Products Research Institute)
Shojiro HISHIYAMA (Forestry and Forest Products Research Institute)
Abstract
Steam-explosion was carried out for the crushing of coal and pore formation. Taiheiyo and Obed-Marsh coals were steam-exploded at 230° C for 6 min. Particle and pore size distributions were measured to determine changes in the coal. This method was found effective for coal crushing and may prove applicable to the formation of small pores in the coal. Better results were obtained by immersing coal in methanol before the explosion.
Key Words : Steam-explosion, Coal pretreatment, Pore structure
(Language: Japanese)
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