Journal of the Japan Institute of Energy
Online ISSN : 1882-6121
Print ISSN : 0916-8753
ISSN-L : 0916-8753
Volume 98 , Issue 12
Showing 1-6 articles out of 6 articles from the selected issue
Table of Contents
Original Paper
  • Tetsuo UMEGAKI, Chinatsu HOSHI, Haruka OGAWA, Shinobu OHKI, Masataka T ...
    Type: Original Paper
    2019 Volume 98 Issue 12 Pages 312-317
    Published: December 20, 2019
    Released: December 27, 2019
    JOURNALS FREE ACCESS

    This work studied about the coordination structure and activity hollow silica-alumina composite spheres for acid-promoted hydrogen evolution from aqueous ammonia borane solution. The hollow spheres were fabricated by adjusting temperature and time for coating their shells on spherical polystyrene templates, following removal of the templates through calcination process. We investigated the influence on the coordination state of active aluminum species through the 27Al MAS NMR spectra and on activity for the hydrogen evolution. The NMR spectra indicated that both the ratios of active tetra-coordinated aluminum species and inactive hexa-coordinated aluminum species also increased with increase of the coating temperature, however, improvement of the activity was not observed despite the increase of the active aluminum species. The ratios of active tetra-coordinated aluminum species and inactive hexa-coordinated aluminum species were also controlled by adjusting the coating time, and the hollow spheres with both high ratio of active tetra-coordinated aluminum species and low ratio of inactive hexacoordinated aluminum species showed high activity for the hydrogen evolution. The highly active hollow spheres also included relatively high ratio of penta-coordinated aluminum atoms, suggesting that the active sites for the hydrogen evolution were also included in the penta-coordinated aluminum species.

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  • Yue MORIIZUMI, Hiroki HONDO, Satoshi NAKANO
    Type: Original Paper
    2019 Volume 98 Issue 12 Pages 318-332
    Published: December 20, 2019
    Released: December 27, 2019
    JOURNALS FREE ACCESS

    In Japan, a large share of final energy demand is used for hot water and space heating and cooling in buildings. Therefore, it is important to consider how to meet the heat demand of residential and commercial sectors. Despite the potential benefits of renewable heat technologies, little study has been done to examine the effects of the introduction of them. The objective of the present study is to develop an input-output model for assessing environmental and socio-economic impacts of renewable heat technologies from a life cycle perspective. The developed input-output model covers three renewable heat systems, namely, solar thermal, ground source heat pump and wood boiler systems. Conventional heat systems are also considered for comparison purposes. The new 37 sectors are created and added to the Japanese input-output table for the year 2011. This study employs a mixed-unit input-output model. The output of the operation sectors is expressed in physical terms instead of monetary terms. Building thermal simulation software is used to calculate heat load. We conduct employment impact assessment using the developed input-output model. The results indicate that the introduction of renewable heat technologies induce employment shifts away from the fossil fuel-related sectors towards renewable sectors.

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Technical Paper
  • Takehiko TAKAHASHI
    Type: Technical Paper
    2019 Volume 98 Issue 12 Pages 333-339
    Published: December 20, 2019
    Released: December 27, 2019
    JOURNALS FREE ACCESS

    In this study, scale-up and continuous pulverization of a vibration mill with ring media were promoted for pretreatment of lignocellulose biomass. In continuous pulverization, coarse powder that passes through the inside of the ring media without being crushed was generated. Then continuous pulverization with a ring and rod combination was examined to suppress the powder flow passing through the ring hole and to increase pulverization force. First, batch pulverization with the ring and rod combination was examined. Results demonstrate that filling the rod media inside the hole of the ring media improved the micronizing efficiency in large amounts of Japanese cedar powder and increased the saccharification efficiency during the initial stage of pulverization. Based on the results, continuous pulverization was examined. The powder flow suppression effect was fundamentally confirmed. Furthermore, powder properties by continuous pulverization were confirmed to be improved in median size and the enzymatic saccharification efficiency by the filling rate of rods from 40% to 50%. Therefore, the ring and rod combination was found to be effective for continuous pulverization using a tandem ring mill.

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  • Junichi KAKUMAZAKI, Hidetoshi KAWABATA, Kei OTA, Tamio IDA
    Type: Technical Paper
    2019 Volume 98 Issue 12 Pages 340-346
    Published: December 20, 2019
    Released: December 27, 2019
    JOURNALS FREE ACCESS

    Bio-coke is carbon-neutral fuel, and expected for CO2 reduction method in some industries using coal coke and foundry coke. Municipal waste incineration facilities in Japan often use gasification melting furnaces due to their high environmental performance and ash volume reduction. Cupola furnaces are also widespread in foundry industry manufacturing ductile iron pipes, gas pipe, etc. This study aims to achieve two objectives: (1) development of effective and economic technology to produce bio-coke from mixed feedstock generated in Yokote City, Akita Prefecture (mainly rice husks, bark and mushroom bed) and (2) demonstration of reduction of CO2 emissions from gasification melting furnace and cupola furnace by using bio-coke as a substitute for coal coke and foundry coke. In the demonstration of using bio-coke at the gasification melting furnace, the coal coke consumption is reduced up to 51%. In the cupola furnace test, the foundry coke consumption is reduced about 5% by using bio-coke. However, some challenges of using bio-coke at the cupola (change of stack gas components, storage condition and mechanical strength, etc.) are identified.

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