Journal of the Japan Institute of Energy
Online ISSN : 1882-6121
Print ISSN : 0916-8753
ISSN-L : 0916-8753
Volume 100 , Issue 9
Showing 1-5 articles out of 5 articles from the selected issue
Table of Contents
Original Paper
  • Akinori MIYAZAWA, Takayuki SEKIGUCHI, Juan C. GONZÁLEZ PALENCIA, Mikiy ...
    Type: Original Paper
    2021 Volume 100 Issue 9 Pages 162-168
    Published: September 20, 2021
    Released: September 30, 2021
    JOURNAL FREE ACCESS

    Performance of a spark ignition engine fueled with NH3/H2 and NH3/CH4 is investigated experimentally. A diesel based four-stroke single-cylinder spark-ignition engine with a stroke volume of 412 cm3 and a compression ratio of 13.7 is used. NH3, H2 and CH4 are supplied from high pressure cylinders and are injected using automobile gaseous fuel injectors. The fuels are mixed in the intake manifold and are delivered to the cylinder. For NH3/CH4, stable combustion is achieved within the equivalence ratio from 0 to 0.50. For NH3/H2, stable combustion is achieved within the equivalence ratio from 0.70 to 0.90. For both NH3/CH4 and NH3/H2, the brake mean effective pressure and the brake thermal efficiency takes a gradual peak with the increase in the NH3 mole fraction in fuel. The NOx concentration jumps up from 3800 ppm for pure CH4 operation to 5500 ppm for the operation with 10 % of NH3. The amount of NOx emission decreases monotonously with the increase in the NH3 mole fraction in fuel due to the reduction effect of NH3. On the contrary, the amount of unburned NH3 increases with the increase in the NH3 mole fraction in fuel, which shown to have close correlation with the quenching layer thickness.

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  • Hui ZHANG, Ryo YOSHIIE, Ichiro NARUSE, Yasuaki UEKI
    Type: Original Paper
    2021 Volume 100 Issue 9 Pages 169-176
    Published: September 20, 2021
    Released: September 30, 2021
    JOURNAL FREE ACCESS

    The effects of hydrocarbon-contained in fuel gas on SOFC with Ni-YSZ as anode are evaluated in this study. Low concentration of toluene was mixed with 96.9% hydrogen and 3.1% steam to simulate bio-syngas, corresponding to current developments of biomass gasification technology. Power generation performance was investigated under Galvano-static-mode with toluene concentrations from 0 mg/Nm3 to 1900 mg/Nm3 at 850 °C for 30 hours. Impedance spectroscopy under OCV conditions was also conducted to assess SOFC’s internal resistance. As the result, SOFC shows a good stability and generation performance without toluene exposure. However, the voltage decreases even under a low concentration of 380 mg/Nm3 while keeping current density constant at 200 mA/cm2. Furthermore, this degradation tends to be serious as concentration of toluene increases. Dramatic voltage drop and visible carbon deposition should not be insignificant when toluene’s concentration was 1900 mg/Nm3. This performance loss seems to be recovered to a certain extent without serious structure destruction on anode.

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  • Katsuhiko YOKOHAMA, Hiroaki WATANABE
    Type: Original Paper
    2021 Volume 100 Issue 9 Pages 177-185
    Published: September 20, 2021
    Released: September 30, 2021
    JOURNAL FREE ACCESS

    Understanding the relationship between volatile matter evolution behavior and chemical structure of coal is important to clarify the reactions in the coal gasification furnace. However, the relationship between 13C-NMR data of coal, the structural parameters of coal based on the chemical percolation degradation (CPD) theory, and the decomposition behavior of coal observed in the high-pressure flow-tube reactor (high pressure DTF) is not fully clarified. In this study, coals with fuel ratios of 0.94 and 1.64 were analyzed by 13C-NMR, then the volatile evolution data was obtained using a high pressure DTF at a temperature range from 800 °C to 1200 °C with residence time from 0.4 s to 0.8 s. By setting the chemical shift peak of bridgehead carbon at 133 ppm and 131 ppm respectively, the calculation results based on the CPD theory agreed with the volatile evolution behavior obtained by the high-pressure DTF experiments. The difference in the chemical shift peak between two coals was attributed to difference in the number of carbon rings constituting the aromatic cluster.

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