Journal of the Japan Institute of Energy
Online ISSN : 1882-6121
Print ISSN : 0916-8753
ISSN-L : 0916-8753
Volume 86 , Issue 7
Showing 1-4 articles out of 4 articles from the selected issue
Original Paper
  • Takashi KUWABARA, Shinji KAMBARA, Hiroshi MORITOMI
    2007 Volume 86 Issue 7 Pages 455-461
    Published: July 20, 2007
    Released: June 27, 2008
    JOURNALS FREE ACCESS
    The aim of this paper is to investigate boron species in coals in order to research partitioning of boron in pulverized coal-fired process. Some extracted coal samples using specific gravity separation and these LTA (Low Temperature Ash) samples were treated with leaching of pure water. Solid-state MAS 11B-NMR spectra of these coals and LTA samples were obtained. Chemical shift of boron species in coal was observed both trigonal and tetrahedral coordinated boron and existent ratio was different with kinds of coal. It was estimated that a part of boron in coal was existed as water-soluble compounds and its chemical form was boric acid and its anhydride, borate of alkaline and alkaline earth metals, and then these compounds minutely dispersed in organic matter of coal.
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Technical Paper
  • Koichi YAMADA, Hiroshi IWASAKI, Yukihiko MATSUMURA, Hiromi YAMAMOTO, K ...
    2007 Volume 86 Issue 7 Pages 462-469
    Published: July 20, 2007
    Released: June 27, 2008
    JOURNALS FREE ACCESS
    Biomass is a carbon neutral material and the development of processes for the use of the bioethanol is being accelerated worldwidely, as its demand for an alternate transportation fuel is increasing. The bioethanol has advantages such as low environmental impacts and high octane number. However, its heat of combustion per unit volume is about 70% of that of gasoline. Even an expected cost by a future NREL process is ¥30/kg-ethanol, it is much higher than an assumed production cost of gasoline of ¥25/l (crude oil, $30/bbl). In order to make the production cost of bioethanol competitive to that of gasoline, the bioethanol process should be rationalized. We reported on the rationalization of the refinement process of the bioethanol in the former report and also the rationalization of the fermentation process using corn stover as biomass resource. Herein, we report on the rationalization of the pretreatment process which uses hot water without sulfuric acid. The cost reduction by the rationalization of the pretreatment process is ¥1.5/kg-ethanol. The production cost of bioethanol is decreased by ¥3.5/kg-ethanol by whole process improvements and calculated to be ¥26.3/kg-ethanol.
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  • Hiroshi IWASAKI, Toshinori KOJIMA, Yukihiko MATSUMURA, Hiromi YAMAMOTO ...
    2007 Volume 86 Issue 7 Pages 470-474
    Published: July 20, 2007
    Released: June 27, 2008
    JOURNALS FREE ACCESS
    Biomass is a carbon neutral material and the development of processes for the use of the bioethanol is being accelerated worldwidely, as its demand for an alternate transportation fuel is increasing. In order to make the production cost of bioethanol competitive to that of gasoline, the bioethanol process should be rationalized. We reported on rationalized process using corn stover as biomass resources. The production cost of bioethanol was decreased by 3.5¥/kg-ethanol by whole process improvements and calculated to be ¥26.3/kg-ethanol. Here, the results of rationalized process design and cost estimation of ethanol using cassava pulp instead of corn stover as biomass resource are reported. Cassava pulp is cheaper than corn stover based on unit ethanol production, however its composition is characterized as low cellulose and hemicellulose, and high starch and water contents compared to those of corn stover. The rationalized process was proposed under the consideration of those complex characteristics of cassava pulp. The production cost of bioethanol could be decreased to ¥22.2/kg-ethanol due to the rationalization in the pretreatment process and the saccharification process. The cost reduction of about ¥8/kg-ethanol or 26% compared to by the future NREL process was obtained.
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Short Paper
  • Masahiro NOGUCHI, Seiichi INOUE
    2007 Volume 86 Issue 7 Pages 475-479
    Published: July 20, 2007
    Released: June 27, 2008
    JOURNALS FREE ACCESS
    Carbonization of model garbage under hydrothermal condition was examined, and then compared with dry condition. The char yields obtained from the model garbage using hydrothermal condition were equal to those using dry condition. The yield and its carbon content at 573K, 0h under hydrothermal condition are 43wt% and 68wt% respectively. The heating value of the char was 30MJ/kg at 573K under hydrothermal condition. As it is higher than the obtained char (25MJ/kg) under dry condition, it is suitable for use as a fuel.
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