日本エネルギー学会誌
Online ISSN : 1882-6121
Print ISSN : 0916-8753
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94 巻 , 9 号
選択された号の論文の5件中1~5を表示しています
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論文
  • Yuichi YOSHIDA, Akiko TAKAHASHI, Jun IMAI, Shigeyuki FUNABIKI
    94 巻 (2015) 9 号 p. 1051-1056
    公開日: 2015/09/30
    ジャーナル フリー
    Photovoltaic (PV) generation has attracted much attention as a new electric-power generation system. However, the output power of PV generation systems experiences significant fluctuations, which negatively affect the electric-power reliability of the grid. It is therefore necessary to smoothen it using power-smoothing control methods. This paper evaluates different power-smoothing control methods using a moving average filter and finite impulse response filters for distributed generation systems with energy storage devices. We analyze the gain and phase characteristics of these filters, and we perform computer simulations to evaluate the effectiveness of the smoothed electric power generated by PV generation systems.
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  • Yoichiro FUKUDA, Masahiko FUJII
    94 巻 (2015) 9 号 p. 1057-1065
    公開日: 2015/09/30
    ジャーナル フリー
    To promote the utilization of biomass energy, it is important to evaluate the potential resource and its distribution and accessibility appropriately. In this study, the available amount of various kinds of biomass resources was estimated based on several statistical data. These data are aggregated into the geodatabase with a uniformed and fine spatial resolution of 1km mesh by estimating its spatial distribution using geographic information system (GIS). Furthermore, the accessibility analysis was performed by the GIS-based network analysis based on the real road network in each region. As a result, the relationship between the accessible time and the resource potential was figured out in each region by this method. Moreover, the transportation costs of each resource were estimated by applying a cost condition. For instance, in Furano City, thinning woods have the highest potential in the entire region. However, crop residues have higher potential in the region accessible from the municipal office as a demand site within 20 minutes. Also, crop residues are considered more reasonable than the others throughout the region in terms of transportation costs.
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  • Gian Powell B. MARQUEZ, Hisae TAKEUCHI, Tatsuya HASEGAWA
    94 巻 (2015) 9 号 p. 1066-1073
    公開日: 2015/09/30
    ジャーナル フリー
    The biogas production of seaweed is commonly patterned to conventional digester wherein the anaerobic condition is optimized for terrestrial biomass. The high salt content of seaweed and its different structural component than terrestrial plants may contribute to low conversion efficiency. Hence, freshwater (FW) and thalassic (TH) anaerobic digestion of Ulva species were compared to determine the more suitable condition. Biological hydrolysis pretreatment (BHP) was done to improve methane yield, while NaOH pretreatment (CNP) was employed to minimize the limitation of biological hydrolysis. Higher biogasification efficiencies based on the theoretical methane yield (285.23 mL CH4/g Volatile Solids [VS]) were obtained using biological hydrolysis pretreatment (FW: 27.23%, TH: 63.42%). However, the biogasification time of BHP was twice as long as that of NaOH. Nonetheless, the methane yield of all pretreatments under thalassic (BHP: 180.9 mL CH4/g VS, CNP: 158.19 mL CH4/g VS) was higher than freshwater’s (BHP: 77.66 mL CH4/g VS, CNP: 61.67 mL CH4/g VS), suggesting a superior methane fermentation under thalassic condition.
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ノート
  • 村上 弥生, 谷 春樹, 朝見 賢二, 藤元 薫
    94 巻 (2015) 9 号 p. 1074-1078
    公開日: 2015/09/30
    ジャーナル フリー
    固定床による高品質なバイオディーゼル(HiBD) の製造技術の開発を行ってきた。従来のダウンフロー方式の固定床を用いて,MgO/SiO2 触媒上で450℃における廃食油の接触分解を行うと,炭素数4から18 の炭化水素の生成油収率は約55%,炭素数19 以上の含酸素化合物の収率は約30%となる。一方,アップフロー方式の固定床を用いて,430℃における廃食油の接触分解を行うと,ダウンフロー方式よりも生成油の収率は60%以上と高くなり,含酸素化合物の収率は減少する。また,原料油に水を加え,エマルジョン状態で反応させると,トリグリセリドから脂肪酸への加水分解反応が促進することにより,ダウンフロー方式とアップフロー方式の両方において生成油の収率が改善されることを見出した。アップフロー方式において,水が存在する場合,水が存在しない場合より生成油の含酸素化合物の収率はわずかに増加したものの,酸価は増加しなかった。以上のことから,アップフロー方式の固定床反応を用いることはHiBD の製造に適していることがわかった。
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