Journal of the Japan Institute of Energy
Online ISSN : 1882-6121
Print ISSN : 0916-8753
ISSN-L : 0916-8753
Volume 80 , Issue 12
Showing 1-4 articles out of 4 articles from the selected issue
  • Toshiharu SATO
    2001 Volume 80 Issue 12 Pages 1131-1139
    Published: December 20, 2001
    Released: June 28, 2010
    JOURNALS FREE ACCESS
    The development of Natural Gas Vehicles (NGVs) in Japan began in the early 1990 under the initiative of the gas utilities. NGVs have subsequently shown a steady expansion. At the end of October 2001, their number was somewhat in excess of 9, 000. NGVs have gradually gained ground as a practical, low emission vehicle. The rapid expansion of NGV has been driven not only by that worldwide mounting interest in a low emission vehicle in the wake of the present-day escalation of the urban air pollution problems and the looming problem of global warming. In part, it is also the cooperation of central and local governments, the gas utilities and the automobile manufacturers and their efforts that have contributed to introduce the NGV. This report summarizes the current situation of NGV proliferation and the trend of vehicle technology in Japan.
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  • Motoyuki SUGANO, Kiyoshi MASHIMO
    2001 Volume 80 Issue 12 Pages 1139-1147
    Published: December 20, 2001
    Released: February 13, 2012
    JOURNALS FREE ACCESS
    It has been widely reported that the hydrothermal pretreatment of coal promotes the subsequent conversion of coal. In this study, the effects of dry thermal (DT) or steam (ST) pretreatment of Adaro subbituminous and Huaipei bituminous coals on the chemical changes of oxygen containing functional groups in coals were discussed with the yields of the subsequent hydrogenolysis reactions of coals. As discussed below, it was considered that the effects of pretreatments varied with the treated temperature and the coal rank. During DT pretreatments of Adaro coal below 150°C and Huaipei coal below 200°C, the cleavage of hydrogen bonds did not affect the subsequent hydrogenolysis reactions. In DT pretreatments of Huaipei coal at 235°C and Adaro coal at 200°C and 250°C, the crosslinking formations among the acidic groups (carboxyl and phenolic hydroxyl groups) in coals developed, followed by the suppression of hydrogenolysis reactions of coals. The contents of the acidic groups in lower rank Adaro coal were higher than those of higher rank Huaipei coal. It was indicated that the crosslinking formations of Huaipei coal occurred at around 235°C, while those of Adaro coal started at the lower temperature, around 200°C. However, the crosslinking formations occurred less during ST pretreatments of coals below 250°C because the hydrogen bonds were freshly formed between the acidic groups and water molecules. Therefore, there was no change between the yields of hydrogenolysis reactions of ST pretreated coals and those of the respective raw coals. Accordingly, for both coals, the hydrolyses of ester and ether crosslinks in coal structures also occurred in ST pretreatment at 300°C, which resulted upgrading on the subsequent hydrogenolysis reactions. However, the crosslinking formation occurred in ST pretreatments of both coals at 350°C, followed by the suppression of the upgrading on the hydrogenolysis reactions of the pretreated coals.
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  • Motoyuki SUGANO, Kiyoshi MASHIMO
    2001 Volume 80 Issue 12 Pages 1140-1147
    Published: December 20, 2001
    Released: June 28, 2010
    JOURNALS FREE ACCESS
    It has been widely reported that the hydrothermal pretreatment of coal promotes the subsequent conversion of coal. In this study, the effects of dry thermal (DT) or steam (ST) pretreatment of Adaro subbituminous and Huaipei bituminous coals on the chemical changes of oxygen containing functional groups in coals were discussed with the yields of the subsequent hydrogenolysis reactions of coals. As discussed below, it was considered that the effects of pretreatments varied with the treated temperature and the coal rank. During DT pretreatments of Adaro coal below 150°C and Huaipei coal below 200°C, the cleavage of hydrogen bonds did not affect the subsequent hydrogenolysis reactions. In DT pretreatments of Huaipei coal at 235°C and Adaro coal at 200°C and 250°C, the crosslinking formations among the acidic groups (carboxyl and phenolic hydroxyl groups) in coals developed, followed by the suppression of hydrogenolysis reactions of coals. The contents of the acidic groups in lower rank Adaro coal were higher than those of higher rank Huaipei coal. It was indicated that the crosslinking formations of Huaipei coal occurred at around 235°C, while those of Adaro coal started at the lower temperature, around 200°C. However, the crosslinking formations occurred less during ST pretreatments of coals below 250°C because the hydrogen bonds were freshly formed between the acidic groups and water molecules. Therefore, there was no change between the yields of hydrogenolysis reactions of ST pretreated coals and those of the respective raw coals. Accordingly, for both coals, the hydrolyses of ester and ether crosslinks in coal structures also occurred in ST pretreatment at 300°C, which resulted upgrading on the subsequent hydrogenolysis reactions. However, the crosslinking formation occurred in ST pretreatments of both coals at 350°C, followed by the suppression of the upgrading on the hydrogenolysis reactions of the pretreated coals.
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  • Tetsuya IWASE, Susumu YOSHIOKA, Hiroshi TAKEZAKI, Nobuyuki HOKARI
    2001 Volume 80 Issue 12 Pages 1148-1155
    Published: December 20, 2001
    Released: June 28, 2010
    JOURNALS FREE ACCESS
    Relationship between the percent of combustion in free board and the conditions of pressurized fluidized bed combustion (PFBC), including the characteristics of coal water paste (CWP), has been studied using 2MWth and 4MWth-PFBC test plant. The 2MWth-PFBC test plant which bed height is 4m and cross sectional area of fluidized bed is 0.28m2, was operated at the bed temperature of 865°C under 0.95MPa pressure in full load condition. The 4MWth-PFBC test plant has two beds which are the same dimensions of 2MWth-PFBC's bed. Six kinds of coal were fed as a CWP. The percent of combustion in free board decreased with increase of bed height, bed temperature and air ratio, also with decrease of superficial gas velocity. The fraction of the fine coal under 0.25mm diameter in CWP affects to the free board combustion. Therefore, it is considered that the free board combustion is due to the decrease of combustion efficiency in the bed, and blowing up of the unburned char from the bed to freeboard. Furthermore, in order to demonstrate the experimental results, a simple calculation model for the free-board combustion was developed. The calculation results have been in good agreement with the experimental results.
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