Journal of the Japan Institute of Energy
Online ISSN : 1882-6121
Print ISSN : 0916-8753
ISSN-L : 0916-8753
Volume 93 , Issue 8
Showing 1-4 articles out of 4 articles from the selected issue
Review
  • Michael J. ANTAL, Jr., Lieve M. HELSEN, Masato KOUZU, Jacques LÉDÉ, Yu ...
    2014 Volume 93 Issue 8 Pages 684-702
    Published: August 20, 2014
    Released: August 29, 2014
    JOURNALS FREE ACCESS
    The rules of thumb for developing thermochemical conversion technology are introduced together with the fundamental rules of thumb for thermochemical conversion, which is the basic idea for these technologies. The target technologies are, (a) metal-impregnated wood treatment by carbonization, (b) fast pyrolysis, (c) supercritical water gasification and, (d) advanced biodiesel production. They are presented in tables in terms of the rule of thumb and its benefit. We hope those who are considering introduction of these technologies will find this paper useful for their plant design and system development. It also should be noted that the scientific background supports the rules of thumb for each technology, and, thus, knowing the rules of thumb will provide insight into the fundamental science of the technology.
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Original Paper
  • Tetsuo UMEGAKI, Yasuhiro WATANUKI, Qiang XU, Yoshiyuki KOJIMA
    2014 Volume 93 Issue 8 Pages 703-709
    Published: August 20, 2014
    Released: August 29, 2014
    JOURNALS FREE ACCESS
    We study the effect of solvents on morphological and/or structural properties and catalytic activity of hollow nickel-silica composite spheres for hydrolytic dehydrogenation of ammonia borane. Nickel-silica composite shells were coated on polystyrene (PS) templates via sol-gel reaction with L(+)-arginine as the promoter of the sol-gel reaction followed or in parallel with the dissolution of the PS templates in the same medium to form hollow spheres. From the transmission electron microscopy (TEM) images, nickel-silica composite shells were formed for 1.5 h, and the surface roughness of the shells increases with the increase of aging time in methyl alcohol, while the shells were formed via the formation of aggregates of irregular shape in ethyl alcohol and 2-propyl alcohol. From the angle attenuated total reflectance infrared (ATR-IR) spectra, the order of dissolution rate of PS templates is 2-propyl alcohol > ethyl alcohol > methyl alcohol. These results indicate that the shells are formed before the dissolution of PS templates in methyl alcohol, while in ethyl alcohol and 2-propyl alcohol, nickel-silica composite shells was formed in parallel with dissolution of PS templates via the formation of aggregates of irregular shape. From the results of N2 adsorption/desorption isotherm analysis, the order of BET surface area is samples prepared in ethyl alcohol > methyl alcohol ≈ 2-propyl alcohol. The catalytic activity for hydrolytic dehydrogenation from aqueous NaBH4/NH3BH3 solution in the presence of the hollow spheres prepared in ethyl alcohol was much higher than those in the presence of the hollow spheres prepared in methyl alcohol and 2-propyl alcohol. Consequently, the solvents were mainly influenced in morphological homogeneity and BET surface area of hollow nickel-silica composite spheres, and these structural properties affected the catalytic activity.
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  • Masahide YASUDA, Ryo KUROGI, Takayuki TOMO, Tsutomu SHIRAGAMI
    2014 Volume 93 Issue 8 Pages 710-715
    Published: August 20, 2014
    Released: August 29, 2014
    JOURNALS FREE ACCESS
    Biodiesel (BDF) has gained much attention as new sustainable energy alternative to petroleum-based fuels. In particular, BDF market has significantly increased in Europe to adhere energy and climate policies. Therefore, the increased BDF production requires new utilization of glycerol which is by product of BDF synthesis. We have focused on photocatalytic reforming using titanium oxide (TiO2) photocatalyst using glycerol as sacrificial agent (SaH). Recently we have found that SaH with all of the carbon attached oxygen atoms such as glycerol and methanol continued to serve as an electron source until their sacrificial ability was exhausted in photocatalyzed hydrogen evolution using a Pt-loaded TiO2 (Pt/TiO2) catalyst. Here we investigated the utilization of residual glycerol in BDF synthesis by photocatalytic reforming. BDF (methyl alkanoate) preparation by transesterification of commercially-available vegetable oil (136.5 g) was performed by heating with MeOH (23.8 g) in the presence of NaOH (0.485 g) at 61 ℃ for 2 h. After cooling, standard follow-up operation was performed as follows. The products were separated into a lower layer (Solution A) and an upper layer. The upper layer was washed with water and separated into a BDF layer and an aqueous washing solution (Solution B). Glycerol (10.4 g) was obtained from Solution A in 73.3% yield along with methanol (6.85 g). BDF (114.5 g) was isolated in 83.7% yield. Solution B contained methanol in 4.38 g. The residual glycerol and unreacted methanol were turned to hydrogen by TiO2-photocatalytic reforming of Solutions A and B using Pt/TiO2 (100 mg) in aqueous solution (150 mL) under irradiation by high-pressure mercury lamp. Hydrogen was evolved in 2.82 g and 0.28 g from Solutions A and B, respectively. The combustion energy (ΔH) of the evolved H2 corresponded to 100.8% based on the total ΔH of glycerol and methanol involved in Solutions A and B. Similar experiment was performed using pre-used vegetable oil. Hydrogen was recovered from Solutions A and B as 69.6% of ΔH. Presence of sodium alkanoate disturbed the hydrogen evolution.
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Technical Paper
  • Tsuguhiko NAKAGAWA, Yuta MITSUMOTO
    2014 Volume 93 Issue 8 Pages 716-724
    Published: August 20, 2014
    Released: August 29, 2014
    JOURNALS FREE ACCESS
    After the Great East Japan Earthquake disaster, it was necessary to build a new energy system that would enable us to be less dependent on nuclear power, as well as reduce carbon dioxide emissions. To accomplish this, it is necessary to consider a new method of energy supply and consumption combined with the promotion of energy conservation and increased the use of natural energy. One example, the energy system through the use of photovoltaic power generation (PV) and electric vehicles (EV) is proposed. However, the conventional system has an issue with increasing DC ⇔AC conversion losses. In this study, the new type of PV and EV combined system which is called “Smart PV and EV system” is proposed. PV generated power is transported by EV in the new system. Therefore, it can be said the two-way energy system. In the new system, Construction location and space PV and battery capacity for EV is optimized for energy consumption of the energy system. Also, a way to cut off the DC ⇔AC conversion loss is proposed. As a result, it is shown that the total utilization efficiency of PV power is improved to above 87%. In addition, the new system economy is improved with improving of total utilization efficiency of PV power.
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