Journal of the Japan Institute of Energy
Online ISSN : 1882-6121
Print ISSN : 0916-8753
ISSN-L : 0916-8753
Volume 93 , Issue 10
Showing 1-12 articles out of 12 articles from the selected issue
Special Articles: Biomass (Original Paper)
  • Megumu INABA, Kazuhisa MURATA, Isao TAKAHARA, Yanyong LIU
    2014 Volume 93 Issue 10 Pages 944-952
    Published: October 20, 2014
    Released: October 31, 2014
    JOURNALS FREE ACCESS
    In fast catalytic pyrolysis of eucalyptus as woody biomass, zeolites enhanced the formation of aromatic hydrocarbons with and without O-atoms, mainly. H-ZSM-5 and H-Beta zeolites were efficient for the formation of non-oxygenated aromatic compounds. High Si/Al2 ratio in H-ZSM-5 depressed the formation of non-oxygenated aromatics, while high Si/Al2 ratio in H-Beta kept high yield of non-oxygenated aromatics. H-mordenite and USY showed a moderate catalytic activity for the formation of phenolic compounds as well as non-oxygenated aromatics, due to moderate catalytic properties. Aromatic compounds may be derived from cellulose, hemicellulose and lignin. In the case of cellulose or hemicellulose as source of aromatics, oxygenated intermediates were formed by thermal decomposition of cellulose or hemicellulose, followed by reaction to form aromatic compounds. In the case of lignin source, oxygenated aromatics were formed by thermal decomposition of lignin, followed by deoxygenation to form non-oxygenated aromatics. Strong solid acidity favors deoxygenation reaction. Moderate solid acidity leads to the formation of phenolic compounds. Large micropore diameter and 3-dimensional microstructure have advantage, since intermediates can contact active sites inside the micropore. Except for SAPO-34, 4A, 13X and Ti-silicate, exhibiting significantly low yield of both of non-oxygenated aromatics and phenols, there seems to be an inversed correlation between yield of non-oxygenated aromatic compounds and that of phenolic compounds.
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  • Aki UMEMURA, Ryohei ENOMOTO, Taku KOUNOSU, Ken ORIHASHI, Yoshiaki KATO ...
    2014 Volume 93 Issue 10 Pages 953-957
    Published: October 20, 2014
    Released: October 31, 2014
    JOURNALS FREE ACCESS
    Along with Japanese cedar bark, fir bark and Japanese larch bark were pyrolyzed to estimate the possibility of utilizing these softwood barks as resources for fine chemicals by comparing the pyrolysis product compositions. The three softwood barks contained higher ash content and yielded lower amount of volatiles when compared with cedar heartwood. The major pyrolysis products from their barks were similar to those previously reported from softwood trunks. Levoglucosan was a major pyrolysis product formed from the three softwood barks, despite being a minor product from wood trunk pyrolysis. Therefore, softwood barks can be expected as a feedstock for production of levoglucosan. An increase in the moisture content in the cedar bark generated more pyrolysis products. This result indicates that softwood barks do not require drying prior to pyrolysis, which simplifies the pyrolysis system.
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  • Jun'ichi HAYASHI, Osamu OKUMA, Syoko FUKUDA, KAGEURA Naoki
    2014 Volume 93 Issue 10 Pages 958-963
    Published: October 20, 2014
    Released: October 31, 2014
    JOURNALS FREE ACCESS
    The cow manure compost was carbonized in temperature range of 400-1000 ℃. The water vapor adsorption property of the prepared char was investigated. A large increase of amount adsorbed of water vapor was found around relative pressure of 0.80. However, in the char prepared at carbonization temperature of 1000 ℃, a large increase of amount adsorbed was disappeared. It was clarified that the increase of the amount adsorbed was attributed to KCl contained in the char. The humidity control property of the cow manure compost char was also investigated. The compost char showed the stable behavior of the adsorption-desorption of water vapor during the cyclic humidity change. It was found that the humidity control property of the cow manure char was superior to that of the commercial wood char for the humidity conditioning.
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  • Miyuki KUROSAWA, Miki KOKUBO, Kiyohiko IGARASHI, Masahiro SAMEJIMA
    2014 Volume 93 Issue 10 Pages 964-972
    Published: October 20, 2014
    Released: October 31, 2014
    JOURNALS FREE ACCESS
    To reduce the enzyme cost for commercial production of ethanol from cellulosic biomass, synergistic improvement of the following three technologies are quite important: (1) Low-cost production of enzymes, (2) Optimization of enzyme cocktail for saccharification to obtain more than 500 g of the sugar yield from 1 kg of biomass in 24 hours incubation, and (3) Recovery and reuse of enzymes. In this work, based on the above concept, a method for standardization of evaluation on the efficiency of enzymatic saccharification process has been established. Using this method, performance of a commercial enzyme cocktail for saccharification of ammonia-treated Erianthus ravennae derived cellulosic biomass has been evaluated and the actual strategy towards reduction of the enzyme cost in our process has been focused. In conclusion, to attain less than 10 JPY of the enzyme cost for 1 L of ethanol production from the ammonia treated cellulosic biomass, most feasible combination of the three technologies are elaborated as follows: the enzyme production cost, 1,000 JPY/kg of enzyme as protein base; the enzyme dose by biomass for saccharification, 1/100; the recovery of enzyme as protein base, more than 75 %.
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  • Efri MARDAWATI, Anett WERNER, Thomas BLEY, KRESNOWATI MTAP, Tjandra SE ...
    2014 Volume 93 Issue 10 Pages 973-978
    Published: October 20, 2014
    Released: October 31, 2014
    JOURNALS FREE ACCESS
    Empty fruit bunches (EFB) of oil palm are the lignocellulosic waste from crude palm oil production. The current practice to deal with the waste is either to burn EFB for energy production or to spread them back on the field as a fertilizer. Both options offer a limited additional value to the industry compared to the use of EFB as a renewable resource for chemicals production. To be used as the raw materials for chemicals production, EFB needs to be hydrolysed first to its sugar-monomer content. This manuscript presents the study of enzymatic hydrolysis of EFB by xylanolytic enzyme. The study covers the evaluation of commercial xylanolytic enzyme in hydrolysing EFB, the effect of temperature, pH, substrate concentration and potential inhibitors in the EFB hydrolysis process, and the influences of thermal pretreatment for enhancing the yield of hydrolysis. The results of this study lead to an increase in the enzymatic hydrolysis process of EFB. The maximum hydrolysis yield was obtained at temperature of 60 ℃ and pH of 5. Both inhibitors, xylose and glucose, affected the hydrolysis process. The results showed that the thermal pretreatment of EFB enhanced the enzymatic hydrolysis yield. Enzymatic hydrolysis was shown to follow Michaelis Menten kinetic model, and the kinetic parameters were obtained to be Km = 22.16 g/L and Vm = 0.17 g/L/min.
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  • Nobuhide TAKAHASHI, Hiromichi NISHIZAWA, Iori SHIMADA, Hiroshi FUKUNAG ...
    2014 Volume 93 Issue 10 Pages 979-985
    Published: October 20, 2014
    Released: October 31, 2014
    JOURNALS FREE ACCESS
    To efficiently utilize inexpensive waste biomass, it has been proposed that municipal solid waste consisting of various raw materials is hydrothermally pretreated to uniformalize their properties and then pyrolytically gasified into syngas. The waste sample consisting of food waste, wood and paper wastes, rice straw and plastic was hydrothermally treated at 175 ℃ and 1.0 MPa. The treated samples with a water content of 0, 30, 59 % (wet basis) were gasified using nitrogen gas containing water vapor and γ-Al2O3 particles as catalyst at 850 ℃. The treated waste was successfully gasified. The results indicated that the gas yield increased with increasing the water content and reached 63% (carbon basis) with the water content of 59 %. Also, this study investigated the influences of hydrothermal treatment on subsequent gasification for Sugi sawdust as a representative of wood waste, and two plastic samples of polyethylene and polystyrene as a representative of plastic waste contained in municipal waste. The results indicated that Sugi sample became more difficult to be gasified after the hydrothermal treatment while the plastic samples were not chemically affected by the hydrothermal treatment.
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  • Huamei YANG, Srinivas APPARI, Shinji KUDO, Jun-ichiro HAYASHI, Satoshi ...
    2014 Volume 93 Issue 10 Pages 986-994
    Published: October 20, 2014
    Released: October 31, 2014
    JOURNALS FREE ACCESS
    This work aims at investigating correlations between primary pyrolysis characteristics of lignin and chemical structure of lignin feedstock. Three different types of lignin samples were prepared through enzymatic hydrolysis, organosolv extraction, and Klason procedure. Analysis by FT-IR and solid state 13C-NMR revealed that the lignin samples exhibited different contents of aromatic carbons, connection carbons, methoxyl carbons, and aliphatic side chains. The three lignin samples were pyrolyzed in a two-stage-tubular reactor at 650 ℃, and pyrolysis products were analyzed with gas chromatographs on-line. More than fifty compounds including inorganic gases, light hydrocarbons (LHs), aromatic hydrocarbons (AHs), phenol derivatives and light non-phenolic oxy-compounds (NPOCs) were gaschromatographically separable and quantified. The influence of the lignin structures on the pyrolysis characteristics was studied, and the correlation of product distribution and lignin chemical structures was examined. The total carbon selectivity into char and tar was increased with increasing lignin aromaticity. Methoxyl group and aliphatic substituents likely contributed for enhancing char formation, while hydrogen in lignin enhanced tar formation. Yields of LHs and NPOCs were increased with increasing aliphatic carbons of the lignin samples. AHs were formed from gas-phase recombination of LHs such as olefins, diolefines and alkynes, rather than directly from aromatic structures in the original lignin likely because of high energy required to cleavage carbon-oxygen bond existed in major structural units such as syringols or guaiacols.
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  • Y. H. TAUFIQ-YAP, S. H. TEO
    2014 Volume 93 Issue 10 Pages 995-999
    Published: October 20, 2014
    Released: October 31, 2014
    JOURNALS FREE ACCESS
    The main challenges facing the commercialization of biodiesel are: profitability, feedstock availability and low cost efficient production process. Although worldwide production of vegetable oil feedstocks is sufficient enough, big area of land needed for cultivating such feedstocks is the major drawback. Algae-biomass (including macro- and microalgae) is gaining interest from many current researchers as they have potential to provide sufficient fuel for global consumption. Algae can be produced fast with high lipid content. Moreover, it can provide food avoiding future starving and allow replacing fossil fuels through carbon-neutral biofuels for combustion machines in the transport, industrial and agricultural sectors. In this study, high grade biodiesel was produced from microalgae derived lipids (Nannochloropsis oculata) via transesterification reaction with methanol using calcium methoxide catalyst. The results showed excellent performances with high yield (92 %) of biodiesel at 60 ℃ compared to the highest yield reported at 22 % with using MgZr catalyst. Interestingly, calcium methoxide catalyst could be also successively reused for five times with the maintained biodiesel yield. Biodiesel produced from microalgae oil had high content of polyunsaturated fatty acids, which made it highly suitable as winter grade biodiesel.
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  • Yusuke KAKUTA, Kentarou MORI, Takuya ITO, Katsumi HIRANO
    2014 Volume 93 Issue 10 Pages 1000-1004
    Published: October 20, 2014
    Released: October 31, 2014
    JOURNALS FREE ACCESS
    Wood biomass attracts attention as a fossil alternative resource. However, the collection of the wood biomass takes cost because the biomass growing region has biased widely. Therefore, it is preferable to convert the wood biomass to an alternative fuel such as diesel oil near where it is discharged. Then, the experiments which use the cellulose and lignin were conducted to clarify the pyrolysis behavior of the wood biomass using the diesel oil as a solvent. Moreover, the physical properties and the combustion characteristic of the diesel oil mixed fuel derived from wood were examined. As a result, the compounds derived from the unit structure of cellulose and lignin were generated by pyrolysis even if diesel oil was used as a solvent. The wood liquefaction concentration in diesel oil mixed fuel was increased when the solvent ratio was decreased. Moreover, this concentration was increased further when the retention time was extended. It was confirmed that the physical properties of diesel oil mixed fuel was suitable to a part of the Japanese Industrial Standards.
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Special Articles: Biomass (Short Paper)
  • Hiroshi NONAKA
    2014 Volume 93 Issue 10 Pages 1005-1009
    Published: October 20, 2014
    Released: October 31, 2014
    JOURNALS FREE ACCESS
    Wood pellet is a good medium for storage and transportation of woody biomass, and so it could be a promising raw material for biorefinery. Since wood components may suffer from heat and pressure during pelletization, it is essential to understand the change of chemical composition. Wood meals with equal size distribution for reliable compositional analysis were prepared from wood pellet (composed of cedar and Japanese cypress) and its raw sawdust before pelletization. Pelletization led to tiny changes in the amount and kinds of ethanol-benzene extractives, in which antifungal chemicals derived from Japanese cypress were mainly observed. Wood pellet has almost the same amount of polysaccharides and lignin as raw sawdust with only slightly less mannose, glucose, galactose in its compositional sugars. Namely, wood pellet has an equivalent potential to be a raw material for production of essential oils, sugars and functional lignins.
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  • Fumiaki KITAHARA, Takahiro YOSHIDA, Hiroyuki TANOUCHI, Aki TARUMI
    2014 Volume 93 Issue 10 Pages 1010-1014
    Published: October 20, 2014
    Released: October 31, 2014
    JOURNALS FREE ACCESS
    We evaluated natural seasoning rate of split logs from wet woody biomass for Japanese cedar (Cryptomeria japonica), konara oak (Quercus serrata) and sawtooth oak (Quercus acutissima) under some conditions differentiated in split length (30, 50, 90 cm) and drying circumstances (roofed or unroofed). Japanese cedar dried out more rapidly than oaks, drying under roofed circumstances was more effective than under unroofed circumstances and short length log enabled more rapid drying. In order to estimate the period of the natural seasoning of split logs, we constructed the formula for drying rate and initial mass.
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Original Paper
  • Hiroshi ABE, Masami AONO, Satoshi KAMEOKA, An-Pan TSAI, Yukihiro YOSHI ...
    2014 Volume 93 Issue 10 Pages 1015-1020
    Published: October 20, 2014
    Released: October 31, 2014
    JOURNALS FREE ACCESS
    AC impedance spectroscopic approach is applied into room temperature ionic liquid (RTIL) based mixtures. The RTIL is hydrophobic 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, [C2mim][TFSI]. For higher efficient electric double layer capacitor (EDLC) as an energy storage device, Cu3Au nanoporous electrode is assembled in the [C2mim][TFSI]-propanol mixtures. Due to high cost and high viscosity of the pure [C2mim][TFSI], an additive is required in order to achieve the low cost and quick electrochemical response for rapid charge/discharge. Propanol having relative low vapor pressure among alcohols is adequate to reduce viscosity of the hydrophobic RTILs. With nanoporous metallic electrode, the EDL capacitance in the mixtures exceed that in the pure [C2mim][TFSI]. Also, the capacitance in the mixtures was large enough up to 80 mol% propanol. In addition, isomer effect of propanol was seen in the AC impedance spectra.
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