Journal of the Japan Institute of Energy
Online ISSN : 1882-6121
Print ISSN : 0916-8753
ISSN-L : 0916-8753
Volume 82 , Issue 8
Showing 1-3 articles out of 3 articles from the selected issue
  • Hiroshi TAKEZAKI, Yoshinori OTANI, Yoshitaka TAKAHASHI
    2003 Volume 82 Issue 8 Pages 588-593
    Published: August 20, 2003
    Released: June 28, 2010
    JOURNAL FREE ACCESS
    A speady, simple and accurate method of characterizing Coal Water Paste (CWP) fluidity has been developed. Pressurized fluidized bed combustion (PFBC) technology has developed for utility applications to generate power. One of the problems concerned with the PFBC is stable feeding of coal to the pressur-ized fluidized bed. There are two types of feeding method, wet and dry.
    The wet feeding method makes coal dryer system eliminated, promotes the reliability of feeding and attains a uniform temperature profile through the bed height because of the wide-spreaded dispersion of CWP in the fluidized bed.
    The water content of CWP has to be as low as possible to have appreciable economics over dry feed-ing. A lower water content without addition of surfactant causes CWP to exhibit higher viscosity than CWM. Given this, main subjects of the wet feeding process are preparation of CWP with lower water content, pumping CWP without seperation of water from CWP.
    In this study, torque in stirring CWP is measured using pin-type rotor. Accuracy of the proposed method has been obviously improved than the cylinder-type viscometer. Measurement error is within 5%. And this method gives simple way to evaluate the minimum water content and suitable size distribu-tion modulus of coal particles in CWP.
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  • Kenji MORI
    2003 Volume 82 Issue 8 Pages 594-602
    Published: August 20, 2003
    Released: July 01, 2011
    JOURNAL FREE ACCESS
    The auther has developed the procedure to forecast world energy demand for about 100 years. The procedure depended on long-range prospect of world population such as published by World Bank and personal energy consumption published by United Nations.
    One of the week point of this procedure is that the accracy of this procedure has not been certified yet, because there is no comparable such long-range prospection of world energy demand.
    Recently long-range prospects of world energy demand till 2000 have been published by WEC and Institute of Energy and Economics Japan. At this time these prospects are compared and it is found that there is no significant discrepancy among these three prospects.
    And also the accuracy of this forcasting procedure is examined by comparison with actual energy consumptions from 1970 till 1997 and the prospect derived from this procedure. And it is found that actual consumptions have followed close after data of the prospect.
    Moreover it is found the discrepancy between data of prospect and actual consumption has appeared by the price change of crude oil.
    Example of applications of this forecasting procedure on present economic situation of Japan and on Kyoto protocol for environment protection are described.
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  • The Effect of Coal Types and Reaction Conditions
    Tsutomu TAKAGI, Shinichi SHIMIZU
    2003 Volume 82 Issue 8 Pages 603-609
    Published: August 20, 2003
    Released: June 28, 2010
    JOURNAL FREE ACCESS
    By using Linear Programming (LP) technique, the production costs of hydrogen and power were minimized in the combination of these production processes, in which the steam reforming of natural gas and off-gas, and the gasification of raw coal and residue produced from the coal liquefaction plant were selected as the hydrogen production process.
    The capital cost and production cost were reduced by introducing the steam reforming of natural gas and off-gas along with the gasification of raw coal and residue. The production of hydrogen by the steam reforming of natural gas reduced the production cost, in which the residue is used for the power generation. On the other hand, the low consumption and the low capital cost were expected in the case of Combined Cycle Generator (CCG), but the production costs of steam-power and hydrogen depended on the price of natural gas.
    In this study, the effects of coal type and liquefaction condition on the production cost and capital cost were discussed at which the boiler turbine generator (BTG) was selected for power generation. The optimal system is closely related to the yield of residue, the hydrogen consumption and the hydrogen production process. The production cost of hydrogen was reduced by increasing oil yield and by decreas-ing the residue. The selection of coal type and reaction condition, which gives more oil and less residue, is essential for the optimal design of hydrogen and power units in coal liquefaction plant.
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