| Hayashi Jun-ichiro | Last modified date：2023.10.10 |
Professor /
Science and Engineering of Materials and Devices, Interdisciplinary Graduate School of Engineering Sciences /
Department of Advanced Device Materials /
Institute for Materials Chemistry and Engineering
Papers
| 1. | Sidra Jabeen,Xiangpeng Gao,Jun-ichiro Hayashi,Mohammednoor Altarawneh,Bogdan Z. Dlugogorski, Effects of product recovery methods on the yields and properties of hydrochars from hydrothermal carbonization of algal biomass, Fuel, 10.1016/j.fuel.2022.126029, 332, 126029, 2023.10, This contribution reports the effects of product recovery methods on the yields and properties of hydrochars produced from hydrothermal carbonization (HTC) of algal biomass. A slurry of Chlorella vulgaris with 10 wt% of solid loading was hydrothermally carbonized at 180 – 220 °C with holding time of 15 and 60 min. The resulting hydrochars were recovered by two prevailing methods, namely direct filtration and dichloromethane (DCM)-aided filtration. The results indicate that, under identical HTC conditions, compared with DCM-aided filtration, direct filtration always results in higher hydrochar yield because of the biocrude retained on its surface. The presence of residue biocrude in the hydrochars from direct filtration further leads to considerable differences in their properties, as compared with their counterparts from DCM-aided filtration. Specifically, under identical HTC temperature and holding time, DCM-aided filtration yields hydrochars of lower volatile matter contents but higher fixed carbon and ash contents, as compared with the hydrochars from direct filtration. Direct filtration generally recovers hydrochars of greater higher heating values and energy-based yields as compared to DCM-aided filtration. The product recovery methods show considerable impacts on the concentrations of Na, K, Mg, and Ca and their retentions in the hydrochars at 220 °C for 60 min, with higher concentrations and retentions of these elements being observed in the hydrochars from DCM-aided filtration. The hydrochars at 220 °C for 15 and 60 min from DCM-aided filtration show higher specific reactivity of 0.040 – 0.058 min−1 and 0.066 – 0.096 min−1 at hydrochar conversions of ≤ 82 % and ≤ 78 %, respectively, as compared with their direct-filtration counterparts, due to their higher concentrations of catalytic alkali and alkaline earth metals. These findings highlight the importance of considering product recovery methods when comparing the yields and properties of hydrochars from HTC of algae reported in the literature.. |
| 2. | Fu WEI,Shinji KUDO,Xinyu WANG,Shusaku ASANO,Jun-ichiro Hayashi, Low Temperature Pyrolysis of Woody Biomass under Steam for Selective Production of Coniferyl Aldehyde, Engineering Sciences Reports, Kyushu University, https://www.tj.kyushu-u.ac.jp/g_public/img/report_img/44-22-29.pdf, 44, 1, 22-29, 2022.10. |
| 3. | Shusaku Asano,Taisuke Maki,Shogo Inoue,Sumito Sogo,Masashi Furuta,Satoshi Watanabe,Yosuke Muranaka,Shinji Kudo,Jun-ichiro Hayashi,Kazuhiro Mae, Incorporative mixing in microreactors: Influence on reactions and importance of inlet designation, Chemical Engineering Journal, doi.org/10.1016/j.cej.2022.138942, 451, 3, 138942, 2023.01. |
| 4. | Jun-ichiro Hayashi Aditya Wibawa, U.P.M. Ashik, Shinji Kudo, Shusaku Asano, Yusuke Dohi, Tetsuya Yamamoto, Yuki Kimura, Xiangpeng Gao, Preparation of Formed Coke from Biomass by Sequence of Torrefaction, Binderless Hot Briquetting and Carbonization, ISIJ International, https://doi.org/10.2355/isijinternational.ISIJINT-2022-013, 62, 8, 1629-1638, 2022.08. |
| 5. | Fu Wei,Shinji Kudo,Shusaku Asano,Jun-ichiro Hayashi, Torrefaction of woody biomass and in-situ pyrolytic reforming of volatile matter: Analyses of products and process heat demand, Journal of Analytical and Applied Pyrolysis, https://doi.org/10.1016/j.jaap.2022.105658, 167, 10568, 2022.08, Torrefaction of Japanese cedar (TR) and in-situ vapor-phase pyrolytic reforming of volatile matter from TR (PYR) were investigated with three main objectives; quantification of the heats required for TR and PYR (QTR and QPYR, respectively), demonstration of high conversion of bio-oil into syngas by PYR without either catalyst or oxidizing agent, and clarification of effects of water washing of the cedar prior to TR on QTR and QPYR as well as the product distribution. The cedar was subjected to TR and PYR at temperatures of TTR = 250–350 °C and TPYR = 500–800 °C, respectively. QTR was defined as the difference in enthalpy between the TR products at TTR and dry cedar at 25 °C, and determined from compound or elemental composition of char, bio-oil, water, and non-condensable gases. QTR increased with TTR in a range of 1.0–4.0% of the cedar HHV, which could be covered by burning the gas and a small portion (0.5–13.0%) of bio-oil from TR at TTR ≥ 280 °C. The water washing removed substantial portions of the inherent alkali and alkaline earth metallic species. This resulted in slight increase in QTR, 0.2–0.8%-HHV and decrease in the gas yield, in particular, those of CO and CO2. PYR converted substantial portions of the bio-oil from TR at TTR = 300 °C. The bio-oil conversion into CO/H2–rich gas was 85–90% at TPYR = 800 °C. QPYR, which was defined as the enthalpy difference between the volatile matter from TR at 300 °C and that from PYR at TPYR, increased with TPYR but as small as 1.4–5.8% of the cedar HHV. The water washing slightly decreased QPYR, and this was quantitatively explained by slightly smaller bio-oil yield from TR of the water-washed cedar at TTR = 300 °C than that of the cedar. QPYR was a function of decrease in the bio-oil yield by PYR, which was not influenced by the water washing.. |
| 6. | Aditya Wibawa,UPM Ashik,Shinji Kudo,Shusaku Asano,Xiangpeng Gao,Jun-ichiro Hayashi, High-Strength Formed Coke from Torrefied Biomass and Its Blend with Noncaking Coal, Energy & Fuels, 10.1021/acs.energyfuels.2c01722, 36, 16, 9121-9132, 2022.08, In continuation of our previous study on production of high-strength metallurgical coke from torrefied softwood (cedar), we studied coke production from a mixture of torrefied cedar (TC) and noncaking coal by pulverization to sizes |
| 7. | Yasuhiro Saito,Aska Mori,Shinji Kudo,Jun-ichiro Hayashi, Hot strength of coke prepared by briquetting and carbonization of lignite, ISIJ International, 10.2355/isijinternational.ISIJINT-202, 2022.08, [URL]. |
| 8. | Yasuhiro Saito,Takumu Higo,Chiho Tsukamoto,Shinji Kudo,Jun-ichiro Hayashi, Estimation of Material Constants of Hot Coke under Inert Atmosphere, ISIJ International, doi.org/10.2355/isijinternational.ISIJINT-2022-190, 2022.08, The strength, pore structure, and material constants of coke prepared from caking coal (Coke A) and non- or slightly caking coal (Coke C) were experimentally and numerically investigated with a particular focus on those values at high temperatures. Coke A showed higher strength and lower porosity than Coke C. The pore structure imaged by X-ray computed tomography was translated to the finite element mesh with the image-based modeling, and the stress analysis based on the finite element method was performed to calculate the mode value of maximum principal stress at different Young's modulus and Poisson's ratio. Young's modulus of Coke A and Coke C at a constant Poisson's ratio decreased and increased, respectively by heating. When the temperature increased, the compression stress of Coke A increased. The result indicated that the coke strength could be increased by heating because of the decrease in apparent Young's modulus, accompanied by the occurrence of creep.. |
| 9. | Takuya Kiyozumi,Shinji Kudo,Aska Mori,Riku Mizoguchi,Atsushi Tahara,Shusaku Asano,Jun-ichiro Hayashi, Synthesis of Oxalate from CO2 and Cesium Carbonate Supported Over Porous Carbon, ISIJ International, 10.2355/isijinternational.ISIJINT-2022-159, 2022.08, [URL], Oxalic acid is an attractive chemical platform potentially available from CO2 due to its established applications and chemical characteristics enabling it to serve as a mediator in hydrometallurgy including iron-making. However, a method for synthesizing oxalic acid from CO2 has yet to be established. In the present work, the formation of oxalate scaffold during heating of cesium carbonate (Cs2CO3) in the presence of CO2 and H2 as reactants was experimentally investigated with a particular focus on the influence of supporting Cs2CO3 over porous materials. Among the support materials examined, activated carbon (AC) had a notable effect in improving the reaction rate and yield of total carboxylates (formate and oxalate) during experiments with an autoclave. An important problem was the dominant presence of formate, the intermediate between carbonate and oxalate, accounting for over 90% of the carboxylates. Changing the reaction conditions, including temperature, reaction time, partial pressure of gas components, and amount of loaded Cs2CO3, did not alter the situation. Alternatively, re-heating of the formate-rich salts over AC under CO and CO2 enhanced the oxalate fraction while maintaining the total carboxylates yield. Benefiting from the employment of support material, the two-step conversion was carried out using a gas-flow type reactor with a packed bed of Cs2CO3 supported over AC. In this reaction system, because water, acting as a promoter, was absent, the total carboxylates yield was lower than that in the autoclave, while the oxalate fraction was higher, being 71.8% with a yield of 43.2% on a Cs2CO3-carbon basis.. |
| 10. | Qianli Wang,Jun-ichiro Hayashi,Shinji Kudo,Shusaku Asano, Fabrication of Densified Rice Husk by Sequential Hot-Compressed Water Treatment, Blending with Polyvinyl Alcohol, and Hot Pressing, ACS Omega, 10.1021/acsomega.2c03286, 7, 31, 27638-27648, 2022.07, Processing agricultural wastes into densified materials to partially substitute wooden product production is significant for reducing the consumption of forest resources. This work proposes the fabrication of high-strength rice husk (RH)-based composite materials with poly(vinyl alcohol) (PVA) via densification by hot pressing. RH was pretreated in hot-compressed water (HCW) prior to pulverization and blending with PVA or PVA/glycerol (GL). The incorporation of PVA greatly improved the strength, toughness, and waterproofness of the composite plate, which was discussed with the help of a variety of composite characterizations. The tensile strength, flexural strength, and toughness of a composite of HCW-treated RH, PVA, and GL with a mass ratio of 80:20:2 were 42, 81 MPa, and 5.9 MJ/m3, respectively. The HCW treatment and blending with PVA and GL improved those properties of the hot-pressed original RH plate by factors of 2.5, 2.3, and 6.7, respectively, and reduced the water uptake and swelling ratio in water by 57 and 53%, respectively, despite the hydrophilic nature of PVA and GL. Altogether, this work outlines a valuable and sustainable approach to the efficient utilization of agricultural wastes.. |
| 11. | Alireza Z Mofrad, Xiangpeng Gao, Ibukun Oluwoye, Jun-ichiro Hayashi, Mohammednoor Altarawneh, Hongwei Wu, Treatment of wastewater from biomass pyrolysis and recovery of its organic compounds with char-assisted drying, Fuel, 10.1016/j.fuel.2021.122825, 312, 122825, 2022.06, [URL], This study proposes a new process that treats pyrolytic wastewater (PWW) from biomass pyrolysis with char-assisted drying. It can be operated at two modes: (I) one-stage drying for PWW treatment; and (II) two-stage drying and condensation for both treating PWW and recovering valuable chemicals (e.g., acetic acid). The process is proved via drying the mixture of a char and a synthetic PWW solution containing acetic acid, acetol, furfural, and phenol at different temperatures (60, 80, and 105 °C) and char-to-PWW mass ratios (1.0, 1.5, and 2.0). The results, supported by density functional theory (DFT) calculations, demonstrate that under Mode I, the char captures over 97.1% of the organic compounds in the PWW at 60 °C and a char-to-PWW ratio of 2.0, while evaporating almost all the water. The evaporated stream can be potentially discharged into the atmosphere without condensation or condensed into wastewater with a significantly reduced content of total organic carbon. Under Mode II, the char-PWW mixture is sequentially dried at 60 and 105 °C, with the exhaust gases being separately condensed. This yields a stream of purified acetic acid solution (concentration: ∼76 wt%) concentrated by a factor of ∼6.3 (compared with the PWW), with a recovery rate of ∼29%.. |
| 12. | Bogdan Z. Dlugogorski Sidra Jabeen, Xiangpeng Gao, Jun-ichiro Hayashi, Mohammednoor Altarawneh, Systematic characterization of biocrude and aqueous phase from hydrothermal carbonization of algal biomass, Journal of Environmental Chemical Engineering, 10.1016/j.jece.2022.107953, 10, 3, 107953, 2022.06, [URL]. |
| 13. | UPM Ashik,Nurulhuda Halim,Shusaku Asano,Shinji Kudo,Jun‐ichiro Hayashi, Kinetics and Mechanisms of Selected Reactions over Hydroxyapatite‐Based Catalysts, Design and Applications of Hydroxyapatite-Based Catalysts, doi.org/10.1002/9783527830190.ch5, 2022.06, Hydroxyapatite (HA) has been extensively investigated and used in the field of biomaterials, while its application is more recently extended to the catalysis. Large number of catalytic processes are currently exploring the unique structural and chemical features of HA. The existence of diverse pair set of Ca 2+ ions results in exclusive catalytic features and provides scope for metal replacement and enables characteristic tuning according to the targeted catalytic application. This chapter explains the kinetics and mechanisms of selected reactions on HA‐based catalysts. Oxidative coupling of methane, partial oxidation of methane, acetone to methyl isobutyl ketone, and ethanol coupling reaction are the major reactions considered for this chapter.. |
| 14. | , [URL]. |
| 15. | Atsushi Tahara, Aska Mori, Jun-ichiro Hayashi, Shinji Kudo, Base-Catalyzed Dehydrogenative Coupling of Formate Anions to Oxalates: Effect of Alkali Metal Cations, ChemRxiv , 10.26434/chemrxiv-2022-6r93n D O I: 10.26434/chemrxiv-2022-6r93n, 2022.05, Herein, the influence of group 1 and 2 metal cations on base-catalyzed dehydrogenative coupling of formate to form oxalate is reported. Treatment of sodium formate with a various types of bases (group 1 and 2 metal carbonates or metal hydroxides) revealed that, compared with carbonate salts, group 1 metal hydroxides behaved as efficient bases for the formation of oxalate, in which cesium hydroxide (CsOH) showed the best catalytic activity. DFT calculation for the reaction mechanism suggested that its kinetic advantage was generated from not only an increase of basicity but also destabilization of the intermediate species due to Na/Cs mixed cation system. The effect of cations in formate salts were also discussed both experimentally and theoretically, in which the yield of oxalic acid depended on thermodynamic stability of both products (oxalate salts) and intermediates.. |
| 16. | Saragai, Shouya; Kudo, Shinji; Sperry, Jonathan; Ashik, UPM; Asano, Shusaku; Hayashi, Jun-ichir, Catalytic deep eutectic solvent for levoglucosenone production by pyrolysis of cellulose, Bioresource Technology, 10.1016/j.biortech.2021.126323, 344, 126323, 2022.01, [URL]. |
| 17. | Qianli Wang, Shinji Kudo, Shusaku Asano, and Jun-ichiro Hayashi, Hot-Compressed Water Treatment and Subsequent Binderless Hot Pressing for High-Strength Plate Preparation from Rice Husk, ACS Sustainable Chem. Eng., 10.1021/acssuschemeng.1c07877, 10, 5, 1932-1942, 2022.01, [URL]. |
| 18. | Xuan-Huynh Pham, UPM Ashik, Jun-Ichiro Hayashi, Alejandro Pérez Alonso, Daniel Pla, Montserrat Gómez, Doan Pham Minh, Review on the catalytic tri-reforming of methane-Part II: Catalyst development, Applied Catalysis A: General, 10.1016/j.apcata.2021.118286, 623, 5, 118286, 2021.08, [URL]. |
| 19. | Tianlong Liu, Xiangpeng Gao, Alireza Zehi Mofrad, Shinji Kudo, Shusaku Asano, Jun-ichiro Hayashi, Leaching Char with Acidic Aqueous Phase from Biomass Pyrolysis: Removal of Alkali and Alkaline-Earth Metallic Species and Uptakes of Water-Soluble Organics, Energy & Fuels, 10.1021/acs.energyfuels.1c01889, 35, 15, 12237-12251, 2021.07, The removal of alkali and alkaline-earth metallic (AAEM) species from biomass and/or its pyrolysis-derived char is often required to mitigate ash-related issues during their combustion. Leaching of biomass with an acidic aqueous phase (AP) produced from its pyrolysis is a promising strategy but encounters several issues, including high moisture content in wet biomass after dewatering and loss of organic carbon from biomass. Here, we propose a new process that leaches char with pyrolytic AP for the removal of AAEM species from and the uptakes of water-soluble organics by char. The char and pyrolytic AP produced from the pyrolysis of wheat straw at 450 °C in an auger reactor were subjected to time-dependent leaching at a liquid-to-solid mass ratio of 20. The results demonstrate that the majority of K, Mg, and Ca are leached within the first hour. Nonacidic compounds in the pyrolytic AP slightly hinder the leaching of K but have no impacts on that of Mg and Ca. Except for acetol, the uptakes of other organic compounds (e.g., furfural and phenolic compounds) by char are rapid in the first hour, become slower in 1–2 h, and then reach equilibrium. The results from density functional theory (DFT) calculations suggest the presence of chemisorption for the interactions between these organic compounds and char. Repeated leaching runs at the optimized leaching time (1 h) suggest that the pyrolytic AP is sufficient for leaching the char from the same run, achieving removal rates of ∼63.7 wt % for K, ∼43.7 wt % for Mg, and ∼60.7 wt % for Ca. After repeated leaching, there are only four organic compounds, including 2,3-butanedione, acetol, 2(5H)-furanone, and the remaining acetic acid, left in the leachate, simplifying the compositions of the pyrolytic AP. Leaching the char, instead of wheat straw, with the pyrolytic AP offers significant advantages, including the reduced moisture content in the wet solid after dewatering, negligible loss of organic carbon, and enhanced capture of phenolic compounds.. |
| 20. | Xin Huang, Daiki Mitsuyama, Shinji Kudo, Jun-ichiro Hayashi, Fast Synthesis of Hydroxymethylfurfural from Levoglucosenone by Mixing with Sulphuric Acid and Heating in a Microtube Reactor, MATEC Web of Conferences, 10.1051/matecconf/202133305005, 333, 2021.06. |
| 21. | Cheolyong Choi, Nozomi Adachi, Wei Zhang, Hiroshi Machida, Jun-ichiro Hayashi, Hiroaki Watanabe, Koyo Norinaga, An approach to simulate vapor phase reactions of coal volatiles in a reducing section of the two stage entrained flow gasifier with a detailed chemical kinetic model, Journal of Chemical Engineering of Japan, 10.1252/jcej.20we171, 54, 6, 334-343, 2021.06, [URL]. |
| 22. | Shinji Kudo, Xin Huang, Shusaku Asano, Jun-ichiro Hayashi, Catalytic strategies for levoglucosenone production by pyrolysis of cellulose and lignocellulosic biomass, Energy & Fuels, 10.1021/acs.energyfuels.1c01062, 35, 12, 9809-9824, 2021.05, [URL], Levoglucosenone (LGO) is a biobased compound that is generated during the pyrolysis of cellulose under catalysis. After several decades of foundational research into production methods, the relatively large-scale industrial production of LGO recently commenced. As a result, research on the application of LGO has increased and extended to the production of commodity chemicals, such as solvents, polymers, resins, and fuels, with LGO as the feedstock, while seeking to minimize production costs. An analysis and summary of previous achievements can help to inform the development of better production methods. We found that existing production methods can be organized into three categories depending on the strategies for exploiting catalysis. This minireview summarizes advances in the technologies used to produce LGO based on each catalytic strategy and recommends possible directions for future research by drawing on knowledge synthesized from the database.. |
| 23. | Chao Li, Jun-ichiro Hayashi, Yifan Sun, Lijun Zhang, Shu Zhang, Shuang Wang, Xun Hu, Impact of heating rates on the evolution of function groups of the biochar from lignin pyrolysis, Journal of Analytical and Applied Pyrolysis, 10.1016/j.jaap.2021.105031, 155, 105031, 2021.05, [URL], Understanding evolution of the functionalities of biochar versus temperature is a prerequisite for exploring application of biochar as functional carbon materials. In this study, pyrolysis of lignin with different heating rates was conducted. The results indicated that the higher heating rate promoted formation of more gases via the accelerated cracking of both the organic components of biochar and the volatile products. In addition, the deoxygenation reactions were suppressed at higher heating rate with short residence time, leading to the biochar with lower heating value and energy yield. The in situ Diffuse Reflection Infrared Fourier Transform Spectra (DRIFTS) characterization of the lignin pyrolysis indicated monotonous increase of the abundance of =C−H, C=C and C−O−C functionalities versus increasing pyrolysis temperature. However, the −OH, −CH3 and C−H2 in alkanes and the C=O were not thermally stable. Abundance of −OH maintained a plateau in 200−450 °C, while that for −CH3 and C−H2 in alkanes also reached maximum at ca. 450 °C and the further increasing heating temperature led to significant decomposition. The decomposition of C=O started at the lower temperatures of 200–325 °C, and the lactones, unconjugated alkyl aldehydes, alkyl esters, conjugated aldehydes/ketones experienced distinct temperature-abundance histories.. |
| 24. | Phatchada Santawaja, Shinji Kudo, Atsushi Tahara, Shusaku Asano, Jun-ichiro Hayashi, Dissolution of Iron Oxides Highly Loaded in Oxalic Acid Aqueous Solution for a Potential Application in Iron-Making, ISIJ International, 10.2355/isijinternational.ISIJINT-2020-726, 2021.04, [URL], Oxalic acid has been identified as a sustainable chemical enabling an efficient recovery of target metals from industrial minerals by dissolution. The dissolution process recently has attracted attention as a key reaction in a potential clean iron-making. In this application to efficiently produce a high-purity iron, the dissolution is required to occur in the absence of light, with no addition of other chemical reagents, and to produce high concentration iron oxalate aqueous solution as fast as possible. To reveal the chemistry of iron oxide dissolution for this application, in the present study, the dissolution experiments are carried out under various conditions with a particular focus on the iron oxide highly loaded in the oxalic acid aqueous solution. Highly acidic oxalic acid solution for dissolving the highly loaded iron oxide enabled the production of iron oxalates aqueous solution with the concentration of up to 0.56 mol-Fe/L. Different from conventional studies under diluted conditions with pH control, the dissolution followed a non-reductive mechanism, producing [Fe3+HC2O4] 2+ as a dominant iron species, and highly correlated with a concentration of proton in the solution. The experimental results and proposed stoichiometries identified a minimum amount of oxalic acid required for the complete dissolution of iron oxide independently from the concentration and type of loaded iron oxide. Among iron oxides tested (α-Fe2O3, FeOOH and Fe3O4) as the feedstock, Fe3O4 had an advantage in the dissolution rate, but showed a relatively low iron recovery in the solution (80–90%) because of an unavoidable formation of FeC2O4· 2H2O precipitates.. |
| 25. | J. X. Wang, J. -i. Hayashi, S. Asano, S. Kudo, Analysis of Primary Reactions in Biomass Oxidation with O2 in Hot-Compressed Alkaline Water, ACS Omega, 10.1021/acsomega.0c05154, 6, 6, 4236-4246, 2021.02. |
| 26. | Xin Huang, Shinji Kudo, Shusaku Asano, Jun-ichiro Hayashi, Improvement of levoglucosenone selectivity in liquid phase conversion of cellulose-derived anhydrosugar over solid acid catalysts, Fuel Processing Technology, 10.1016/j.fuproc.2020.106625, 212, 106625, 2021.02, The pyrolysis of cellulose produces anhydrosugars, levoglucosan (LGA) in particular, as a primary product. In this work, the liquid phase conversion of anhydrosugars over solid acid catalysts was investigated, mainly using LGA, as a method for producing levoglucosenone (LGO), which is a bio-renewable platform for fine and commodity chemicals. The screening of typical organic solvents revealed they had a significant influence on the type of reaction selectivity and identified dimethyl sulfoxide (DMSO) as a suitable solvent. Among the solid acid catalysts examined, Amberlyst 70 in combination with DMSO was found to work the best, producing LGO with a yield of up to 32.3%-C. The yield of LGO was further improved to 40.4%-C by in-situ removal of water, which promoted undesired reactions, such as hydrolysis of LGA and isomerization of LGO to hydroxymethylfurfural. Moreover, an experiment using bio-oil, derived from cellulose pyrolysis, as the feedstock showed that a portion of heavier saccharides contributed as a source of LGO without inhibiting the conversion of LGA.. |
| 27. | Jing-Xian Wang, Shusaku Asano, Shinji Kudo, Jun-ichiro Hayashi, Deep Delignification of Woody Biomass by Repeated Mild Alkaline Treatments with Pressurized O2, 10.1021/acsomega.0c03953, 5, 45, 29168-29176, 2020.11, [URL], Delignification is essential in effective utilization of carbohydrates of lignocellulosic biomass. Characteristics of the delignification are important for the yield and property of the resulting carbohydrates. Oxidation with O2 of biomass in alkaline water can potentially produce high-purity cellulose at high yield. The present authors chose a Japanese cedar and investigated its oxidative delignification at 90 °C. The delignification selectivity was determined mainly by the chemical structures of lignin and cellulose. Treatment conditions, except for temperature, hardly changed the relationship between delignification rate and cellulose retention. During the treatment, dissolved lignin underwent chemical condensation in the aqueous phase. This “unfavorable” condensation consumed O2-derived active species, slowing down further delignification. Repeated short-time oxidation with renewal of alkaline water suppressed the condensation, enhancing the delignification. Repetition of 2-h treatments four times achieved 96% delignification, which was 8% higher than a single 8-h treatment at 130 °C.. |
| 28. | Tianlong Liu, Shusaku Asano, Shinji Kudo, Jun-ichiro Hayashi, Sequential conversion of lignite in alkaline water by oxidative degradation, dissolution and catalytic gasification, Fuel, 10.1016/j.fuel.2020.118329, 278, 118329, 2020.10, We have demonstrated a sequence of degradation, dissolution and catalytic hydrothermal gasification (CHTG) oflignite in alkaline water. A Victorian lignite was subjected to hydrothermal treatment (HT) in an aqueous so-lution of NaOH at 250 °C, and then oxidation with pressurized O2at 100 °C. The sequential HT and oxidationsolubilized a 95% portion of the lignite on mass/carbon bases. The resulting solution was further converted byCHTG in a flow reactor at 350 °C for 10 h, employing a ruthenium/activated-charcoal catalyst (rutheniumloading; 16 wt%). The initial carbon conversion to gas was as high as 98% while CH4, CO2and H2were pro-duced. The conversion gradually decreased due to coke deposition over the catalyst but was near steady around83% at 8–10 h. The solubilized lignite consisted of compounds with molecular mass up to 5,000. The heavierportion (molecular mass > 1,000) was responsible for the coke formation and accumulation that caused thecatalyst deactivation.. |
| 29. | Phatchada Santawaja, Shinji Kudo, Aska Mori, Atsushi Tahara, Shusaku Asano, Jun-ichiro Hayashi, Sustainable Iron-Making Using Oxalic Acid: The Concept, A Brief Review of Key Reactions, and An Experimental Demonstration of the Iron-Making Process, ACS Sustainable Chemistry & Engineering, 10.1021/acssuschemeng.0c03593, 8, 35, 13292-13301, 2020.08. |
| 30. | Huang, Xin; Kudo, Shinji; Ashik, UPM; Einaga, Hisahiro; Hayashi, Jun-ichiro; , Selective Hydrodeoxygenation of γ-Valerolactone over Silica-supported Rh-based Bimetallic Catalysts, Energy & Fuels, 2020, 34, 6, 7190–7197, 2020.05. |
| 31. | Liu, Tianlong; Mori, Asuka; Arai, Ryohei; Asano, Shusaku; Kudo, Shinji; Hayashi, Jun-ichiro; , Selective production of phenolic monomers and biochar by pyrolysis of lignin with internal recycling of heavy oil, Energy & Fuels, 2020, 34, 6, 7183–7189, 2020.05. |
| 32. | Ashik, UPM; Abbas, Hazzim F; Abnisa, Faisal; Kudo, Shinji; Hayashi, Jun-ichiro; Daud, WMA Wan; , Methane decomposition with a minimal catalyst: An optimization study with response surface methodology over Ni/SiO2 nanocatalyst, International Journal of Hydrogen Energy, Volume 45, Issue 28, 21 May 2020, Pages 14383-14395, 2020.05. |
| 33. | Huang, X., Yamasaki, K., Kudo, S., Sperry, J., Hayashi, J.-i., Influence of ionic liquid type on porous carbon formation during the ionothermal pyrolysis of cellulose, Journal of Analytical and Applied Pyrolysis, 10.1016/j.jaap.2019.104728, 145, 104728, 2020.01. |
| 34. | Tsuboi, Y., Kumagai, Y., Suda, T., Hayashi, J.-i., Segregation of char and silica sand particles in a hot-fluidized-bed steam gasifier, Advanced Powder Technology, 10.1016/j.apt.2019.12.005, 2020.01. |
| 35. | Kudo, S., Okada, J., Ikeda, S., Yoshida, T., Asano, S., Hayashi, J.-i., Improvement of Pelletability of Woody Biomass by Torrefaction under Pressurized Steam, Energy & Fuels, 10.1021/acs.energyfuels.9b02939, 2020.01. |
| 36. | Asano, S., Choi, C., Ishiyama, K., Kudo, S., Gao, X., Hayashi, J.-i., Re-examination of Thermogravimetric Kinetic Analysis of Lignite Char Gasification, 10.1021/acs.energyfuels.9b02946, 2020.01. |
| 37. | Jabeen, S., Gao, X., Altarawneh, M., Hayashi, J.-i., Zhang, M., Dlugogorski, B.Z., Analytical Procedure for Proximate Analysis of Algal Biomass: Case Study for Spirulina platensis and Chlorella vulgaris, Energy & Fuels, doi.org/10.1021/acs.energyfuels.9b03156, 2020.01. |
| 38. | Ashik, UPM; Asano, Shusaku; Kudo, Shinji; Pham Minh, Doan; Appari, Srinivas; Hisahiro, Einaga; Hayashi, Jun-ichiro; , The Distinctive Effects of Glucose-Derived Carbon on the Performance of Ni-Based Catalysts in Methane Dry Reforming, Catalysts, 2020.01. |
| 39. | Chen, L., Nakamoto, R., Kudo, S., Asano, S., Hayashi, J.-i., Biochar-Assisted Water Electrolysis, Energy & Fuels, 10.1021/acs.energyfuels.9b02925, 33, 11, 11246-11252, 2019.12. |
| 40. | Halim, Nurulhuda; Tajima, Akira; Asano, Shusaku; Kudo, Shinji; Hayashi, Jun-ichiro; , Change in Catalytic Activity of Potassium during CO2 Gasification of Char, Energy & Fuels, 10.1021/acs.energyfuels.9b02925, 34,1,225-234, 2019.12. |
| 41. | Halim, N., Ashik, U.P.M., Gao, X., Kudo, S., Sanwani, E., Norinaga, K., Hayashi, J.-i., Quantitative Description of Catalysis of Inherent Metallic Species in Lignite Char during CO2 Gasification, Energy & Fuels, 10.1021/acs.energyfuels.9b00465, 33, 7, 5996-6007, 2019.11. |
| 42. | Tsuji, M., Miyano, M., Kamo, N., Kawahara, T., Uto, K., Hayashi, J.-i., Tsuji, T., Photochemical degradation of acrolein using VUV excimer lamp in air at atmospheric pressure, International Journal of Environmental Science and Technology, 10.1007/s13762-019-02404-5, 16, 11, 7229-7240, 2019.10. |
| 43. | Masahiro Matoba, Shinji Kudo, Aska Mori, Koyo Norinaga, Yusuke Dohi, Kazuya Uebo, Jun-ichiro Hayashi, Production of High-strength Cokes from Non-/Slightly Caking Coals. Part I: Effects of Coal Pretreatment and Variables for Briquetting and Carbonization on Coke Properties, ISIJ International, 10.2355/isijinternational.ISIJINT-2018-819, 59, 8, 1440-1448, 2019.08, In continuation of the present authors’ studies on production of high strength coke from lignite by sequential binderless hot briquetting and carbonization, this study has been carried out aiming at proposing methods to produce high strength coke from non-/slightly caking coals of subbituminous to bituminous rank. This paper firstly demonstrates preparation of cokes with cold tensile strengths above 10 MPa from two single non-caking coals (particle size; |
| 44. | Kenya Uchida, Shinji Kudo, Aska Mori, U.P.M. Ashik, Koyo Norinaga, Yusuke Dohi, Kazuya Uebo, Jun-ichiro Hayashi, Production of High-strength Cokes from Non- and Slightly Caking Coals. Part II: Application of Sequence of Fine Pulverization of Coal, Briquetting and Carbonization to Single Coals and Binary Blends, ISIJ International, 10.2355/isijinternational.ISIJINT-2018-847, 59, 8, 1449-1456, 2019.08, Sequential coal briquetting and carbonization was applied to preparation of cokes from 9 non- or slightly caking coals with carbon contents (fC) of 67–85 wt%-daf. Coal pulverization to sizes of |
| 45. | Tetsuya Fukuoka, Norihiro Takeda, Lu Zhang, Hirochi Machida, Wei Zhang, Masahiko Watanabe, Yuko Nishibata, Jun-ichiro Hayashi, Koyo Norinaga, Quantitative Analyses of Chemical Structural Change and Gas Generation Profile of Coal upon Heating Toward Gaining New Insights for Coal Pyrolysis Chemistry, ISIJ International, 10.2355/isijinternational.ISIJINT-2018-816, 59, 8, 1376-1381, 2019.08. |
| 46. | Fukuoka, Tetsuya; Takeda, Norihiro; Zhang, Lu; Machida, Hiroshi; Zhang, Wei; Watanabe, Masahiko; Nishibata, Yuko; Hayashi, Jun-ichiro; Norinaga, Koyo; , Quantitative Analyses of Chemical Structural Change and Gas Generation Profile of Coal upon Heating toward Gaining New Insights for Coal Pyrolysis Chemistry, isij international, 10.2355/isijinternational.ISIJINT-2018-816, 59,8,1376-1381, 2019.07. |
| 47. | Xin Huang, Shinji Kudo, Jun-ichiro Hayashi, Two-step conversion of cellulose to levoglucosenone using updraft fixed bed pyrolyzer and catalytic reformer, Fuel Processing Technology, 10.1016/j.fuproc.2019.03.014, 191, 29-35, 2019.06. |
| 48. | Tsuji M., Miyano M., Kamo N., Kawahara T., Uto K., Hayashi J.-I., Tsuji T., Photochemical removal of acetaldehyde using 172 nm vacuum ultraviolet excimer lamp in N2 or air at atmospheric pressure, Environmental Science and Pollution Research, 10.1007/s11356-019-04475-w, 26, 11, 11314-11325, 2019.06. |
| 49. | Hiromi Ishii, Tomoya Hayashi, Hiroaki Tada, Katsuhiko Yokohama, Ryuhei Takashima, Jun-Ichiro Hayashi, Critical assessment of oxy-fuel integrated coal gasification combined cycles, Applied Energy, 10.1016/j.apenergy.2018.10.021, 233-234, 156-169, 2019.01, Critical assessment was performed for a type of oxy-fuel integrated coal gasification combined cycles (IGCC) that was comprised of proven components. A type of two-stage entrained-flow gasifier consisting of combustor and reductor sections was simulated by a one-dimensional model that has been proven through application to gasifiers of industrial scales. It was successfully reproduced on Aspen Plus® and integrated together with the other components into a commercial-scale IGCC system. The oxidizing agents were not only O2 and CO2 (carrier gas for conveying the coal) but also additional CO2 or CO2 /H2 O, that was required to suppress hydrocarbons formation and maintain the combustor temperature allowing molten ash to have sufficiently low viscosity. The net thermal efficiency was predicted as a function of steam/coal mass ratio (S/C) within a range of 0–0.4. Increasing S/C up to 0.2 increased the cold gas efficiency slightly but resulted in decrease in the net thermal efficiency of the system. This was mainly due to the extraction of steam from the high pressure steam turbine exhaust, causing loss of power output. Resulting in lower cold gas efficiency due to higher oxygen ratio, higher moisture content of the pulverized coal gave higher net thermal efficiency due to less steam consumption for coal drying. The net efficiency was optimized at approximately 39% on a higher-heating-value basis without steam feeding, which was higher by 6–7 points than that for conventional IGCC with oxygen-blown gasification combined with CO2 recovery.. |
| 50. | Cheolyong Choi, U.P.M. Ashik, Shinji Kudo, Kazuya Uebo, Koyo Norinaga, Jun-ichiro Hayashi, Effect of SiO2 on loss of catalysis of inherent metallic species in CO2 gasification of coke from lignite, Carbon Resources Conversion, 10.1016/j.crcon.2018.09.002, 2, 13-22, 2019.01, Inherent metallic species retained by coal char or coke, such as Na and Ca, behave as catalysts in gasification. The char/coke normally contains inherent SiO2, which can react with the inherent catalysts to form silicates, resulting in catalyst deactivation over the range of pyrolysis, carbonization and gasification, and thereby re- ducing the char/coke reactivity. The present authors simulated the inherent catalyst deactivation experimentally by blending a Victorian lignite with SiO2, briquetting the SiO2/lignite blend, carbonizing the briquette, and then gasifying the coke with CO2. The kinetic analysis of the gasification employed a comprehensive model, which assumed progress in parallel of non-catalytic and catalytic gasification. The model quantitatively described the measured kinetics of the coke gasification with different SiO2 contents over a range of coke conversion up to 99.9%. The kinetic analysis revealed that the SiO2 deactivated substantial and entire portions of the most active catalyst and its precursor, respectively, before the gasification (i.e., during the carbonization). The catalyst deactivation also occurred during the gasification, but mainly following a self-deactivation mechanism that involved no silicates formation.. |
| 51. | Cheolyong Choi, Kentaro Shima, Shinji Kudo, Koyo Norinaga, Xiangpeng Gao, Jun-ichiro Hayashi, Continuous monitoring of char surface activity toward benzene, Carbon Resources Conversion, 10.1016/j.crcon.2018.12.001, 2, 43-50, 2019.01, Kinetics of thermal decomposition of benzene on lignite-derived char was investigated at 900 °C by applying a new method to continuously monitor the char surface activity. Benzene vapor was continuously forced to pass through a micro fixed bed of char with residence time as short as 7.6 ms, and then detected continuously by a flame-ionization detector. Results showed the presence of two different types of char surfaces; consumptive Type I surface and non-consumptive (sustainable) Type II surface. Type I surface of a partially CO2-gasified char had an capacity of carbon deposit from benzene over 20 wt%-char and an initial activity (represented by a first-order rate constant) as high as 160 s−1. Both of them decreased with increasing carbon deposit due to consumption of micropores accessible to benzene, and finally became zero leaving Type II surface that had a very stable activity with rate constant of 4 s−1. The chars without gasification had capacities of Type I surfaces smaller by two orders of magnitude than the partially gasified char, while the Type II surfaces had activities similar to that of the partially gasified char. It was found that Type II surface converted benzene into not only carbon deposit but also diaromatics and even greater aromatics. Composition of the greater aromatics was unknown because they were deposited onto the reactor wall immediately after passing through the char bed.. |
| 52. | Zhang, L., Qi, S.-C.., Takeda,N., Kudo, S., Hayashi, J.-i., Norinaga, K., Characteristics of gas evolution profiles during coal pyrolysis and its relation with the variation of functional groups, International Journal of Coal Science and Technology, 10.1007/s40789-017-0175-0, 5, 4, 452-463, 2018.12. |
| 53. | Masaharu Tsuji, Takashi Kawahara, Keiko Uto, Naohiro Kamo, Masato Miyano, Hayashi Jun-Ichiro, Takeshi Tsuji, Efficient removal of benzene in air at atmospheric pressure using a side-on type 172 nm Xe2 excimer lamp, Environmental Science and Pollution Research, 10.1007/s11356-018-2103-2, 25, 19, 18980-18989, 2018.07. |
| 54. | Ashik, UPM; Viswan, Anchu; Kudo, Shinji; Hayashi, Jun-ichiro; , Nanomaterials as Catalysts, Applications of Nanomaterials, 45-82, 2018.06, [URL]. |
| 55. | Ashik, UPM; Kudo, Shinji; Hayashi, Jun-ichiro; , An overview of metal oxide nanostructures, Synthesis of Inorganic Nanomaterials, 10.1016/B978-0-08-101975-7.00002-6, 19-57, 2018.06. |
| 56. | Zayda Faizah Zahara, Shinji Kudo, Daniyanto, U. P.M. Ashik, Koyo Norinaga, Arief Budiman, Hayashi Jun-Ichiro, CO2 Gasification of Sugar Cane Bagasse Quantitative Understanding of Kinetics and Catalytic Roles of Inherent Metallic Species, Energy & Fuels, 10.1021/acs.energyfuels.7b03147, 32, 4, 4255-4268, 2018.04, A total of 18 chars from the pyrolysis of six trios of sugar cane bagasses (SCBs; original, water-washed, and acid-washed) were gasified with CO2 at 900 °C, aiming at a quantitative description of the rate of gasification catalyzed by inherent metallic species and a correlation of the catalytic activity and its change during the gasification with the metallic species composition. The measured kinetics was described quantitatively over a range of char conversion, 0-0.999, by a model that assumed progress in parallel of the catalytic gasification and non-catalytic gasification, together with the presence of a catalytic precursor and three to four types of catalysts having different activities and deactivation characteristics. A series of regression analyses was scrutinized and reached expression of initial catalytic activity as a linear function of Na, K, Ca, Fe, and Si concentrations in the char with a correlation factor (r2) of >0.98. The catalyst precursor contributed fully by water-soluble Na, K, and Ca. Si was responsible for the catalyst deactivation during the pyrolysis but not during the gasification. The chars produced from original SCBs followed a linear relationship between the initial catalytic deactivation rate and initial activity (r2 > 0.99), while such a linear relationship was not valid for those formed from the water-washed SCBs. This was explained mainly by more rapid deactivation of the Fe catalyst in the chars from water-washed SCBs than that in the chars formed from the original SCBs. Na and K in char from the original SCBs, originating from the water-soluble SCBs, chemically interacted with the Fe catalyst, slowing its deactivation.. |
| 57. | Shinji Kudo, Aska Mori, Gentaro Hayashi, Takuya Yoshida, Noriyuki Okuyama, Koyo Norinaga, Hayashi Jun-Ichiro, Characteristic Properties of Lignite to Be Converted to High-Strength Coke by Hot Briquetting and Carbonization, Energy & Fuels, 10.1021/acs.energyfuels.7b03155, 32, 4, 4364-4371, 2018.04, A sequence of hot briquetting and carbonization (HBC) is a promising technology for the production of coke with a high mechanical strength from lignite, but factors affecting the coke strength have not yet been fully understood. The HBC cokes prepared from 12 lignites in this study showed diverse tensile strength (e.g., from 0.2 to 31.2 MPa in the preparation at 200 °C and 112 MPa for hot briquetting and 1000 °C for carbonization), and the coke strengths could not be explained by differences in commonly used structural properties of the parent lignites, such as elemental composition and contents of volatile matter/fixed carbon and ash. In this study, two methods were proposed for correlating the coke strength with the lignite properties, which employed the chemical structure analyzed by solid-state 13C nuclear magnetic resonance or the volumetric shrinkage during carbonization. A stronger coke was obtained from lignite that contained more aliphatic carbons (less aromatic carbons) or shrank more considerably. These characteristics contributed to intensified compaction of lignite in the briquetting and suppression of the formation of large pores, which are a cause of coke fracture. Two empirical equations, predicting the coke strength from the parameters of lignite properties, were established to be criteria for selection of lignite as HBC coke feedstock, although further investigation with more experimental data would be necessary for the validation.. |
| 58. | Yuki Furutani, Yuki Dohara, Shinji Kudo, Jun-ichiro Hayashi, Koyo Norinaga, Computational Study on the Thermal Decomposition of Phenol-Type Monolignols, International Journal of Chemical Kinetics, 10.1002/kin.21164, 50, 4, 304-316, 2018.04, A detailed chemical kinetic model has been developed to theoretically predict the pyrolysis behavior of phenol-type monolignol compounds (1-(4-hydroxyphenyl)prop-2-en-1-one, HPP; p-coumaryl alcohol, 3-hydroxy-1-(4-hydroxyphenyl)propan-1-one, HHPP; 1-(4-hydroxyphenyl)propane-1,3-diol, HPPD) released from the primary heterogeneous pyrolysis of lignin. The possible thermal decomposition pathways involving unimolecular decomposition, H-addition, and H-abstraction by H and CH3 radicals were investigated by comparing the activation energies calculated at the M06–2X/6–311++G(d,p) level of theory. The results indicated that all phenol-type monolignol compounds convert to phenol by side-chain cleavage. p-Coumaryl alcohol decomposes into phenol via the formation of 4-vinylphenol, whereas HPP, HHPP, and HPPD decompose into phenol via the formation of 4-hydroxybenzaldehyde. The pyrolytic pathways focusing on the reactivity of the hydroxyl group in HPP and producing cyclopentadiene (cyc-C5H6) were also investigated. The transition state theory (TST) rate constants for all the proposed elementary reaction channels were calculated at the high-pressure limit in the temperature range of 300–1500 K. The kinetic analysis predicted the two favorable unimolecular decomposition pathways in HPP: the one is the dominant channel below 1000 K to produce cyc-C5H6, and the other is above 1000 K to yield phenol (C6H5OH).. |
| 59. | Xiongchao Lin, Yuanping Yang, Xujun Chen, Caihong Wang, Jun-ichiro Hayashi, Yonggang Wang, Investigation on the Occurrences and Interactions of Corrosive Species during Pyrolysis of Zhundong Coal Using SSNMR and HT-XRD, Energy and Fuels, 10.1021/acs.energyfuels.8b00661, 32, 4, 5062-5071, 2018.04, The utilization of a typical Chinese low-rank coal (Zhundong coal) usually gives rise to severe fouling and slagging in equipment due to its excessively high content of sodium-bearing corrosive substances. This study systematically clarifies the occurrences and transformation mechanism of corrosive materials during pyrolysis of Zhongdong coal by combining solid-state nuclear magnetic resonance (SSNMR), in situ high-temperature X-ray diffraction (HT-XRD), and Factsage simulation. For the first time, the experimental evidence in this study shows that the corrosive elements demonstrated distinct forms in coal and could be significantly varied by thermal treatment. Specifically, homogeneously distributed Na ions could mutually transform between inorganic and organic-bounded form under the influence of ionic force, resulting in its elutable feature. During pyrolysis, Na was successively transformed to be inorganic form and completely volatilized above 800 °C, thus diversifying Na-related fouling propensity in various pyrolysis stages. The Cl was unlikely to entirely exist as inorganic form; nevertheless it was strongly restrained by functional groups of coal matrix. The organic Cl-containing functional groups was gradually decomposed to volatile Cl at pyrolysis temperature higher than 500 °C, whereas the inorganic Cl was more stable and possibly exposed on the surface of char particle. In situ analysis further revealed that the formation of aerosol by the diffused corrosive elements was the key step leading to the deposition. More importantly, Factsage thermodynamic calculation demonstrates that the sequential release of Cl as well as S, and their interactions with Na are the prerequisite and essential factor governing the generation of low-temperature-eutectic and subsequently initial corrosion.. |
| 60. | Masaharu Tsuji, Kanako Matsuda, Mayu Tanaka, Satsuki Kuboyama, Keiko Uto, Nozomi Wada, Hirofumi Kawazumi, Takeshi Tsuji, Hiroki Ago, Hayashi Jun-Ichiro, Enhanced Photocatalytic Degradation of Methyl Orange by Au/TiO2 Nanoparticles under Neutral and Acidic Solutions, ChemistrySelect, 10.1002/slct.201702664, 3, 5, 1432-1438, 2018.02, A comparative study was carried out on the degradation of methyl orange (MO) by TiO2 and Au/TiO2 photocatalysts in neutral and acidic solutions. Au/TiO2 photocatalysts with an Au : Ti atomic ratio of 1.5±0.1% : 98.5±0.1% were prepared by using a microwave-polyol method in the presence of P25 TiO2. Initial degradation rates of MO by TiO2 and Au/TiO2 were 0.13 and 0.22 min−1 at pH 7, whereas they increased to 0.96 and 3.06 min−1 at pH 2, respectively. These results indicate that the MO degradation rates are enhanced by loading Au nanoparticles on TiO2 in neutral and acidic solutions by factors of 1.7 and 3.2, respectively. Mass spectroscopic studies lead us to conclude that major reaction products are formed by demethylation and OH addition of benzenoid form of MO in neutral solutions, whereas they are produced through ring opening and carboxylation of quinonoid form of MO after scission of a center N-NH bond in acidic solutions. The relative importance of electron trapping and surface plasmon resonance (SPR) effects of Au nanoparticles is discussed for the enhancement of photocatalytic activity of Au/TiO2.. |
| 61. | Zhepeng Tang, Aijun Li, Tomo Hatakeyama, Hiroki Shuto, Jun-ichiro Hayashi, Koyo Norinaga, Transient three-dimensional simulation of densification process of carbon fibre preforms via chemical vapour infiltration of carbon matrix from methane, Chemical Engineering Science, 10.1016/j.ces.2017.10.029, 176, 107-115, 2018.02, Chemical vapour infiltration (CVI) is widely used for fabricating carbon fibre-reinforced carbon materials for aircraft brake disks. This study aims at developing a numerical simulation method for predicting densification of the material during the CVI. Based on the multi-step reaction and deposition models, including the hydrogen inhibition model of pyrocarbon growth, transient 3D simulations of the CVI using methane as a precursor of the pyrocarbon were carried out via the finite element method coupling the mass transfer (by convection and diffusion) and the evolutive porous structure model with gas-phase and surface chemical reactions. The CVI of two different types of preforms was studied. The pore structure evolution models were derived not analytically but numerically with the aid of a computational tool for visualizing the fibre structures. An acceptable agreement was found between the predicted densification profiles and the experimental data obtained using a laboratory CVI reactor at a temperature of 1343 K, a methane pressure of 30 kPa and a total deposition time of 120 h.. |
| 62. | Yuki Furutani, Shinji Kudo, Jun-ichiro Hayashi, Koyo Norinaga, Predicting molecular composition of primary product derived from fast pyrolysis of lignin with semi-detailed kinetic model, Fuel, 10.1016/j.fuel.2017.10.079, 212, 515-522, 2018.01, A numerical approach is presented for predicting the yields of char and volatile components obtained from fast pyrolysis of three types of lignin (enzymatic hydrolysis lignin, EHL; organic extracted lignin, OEL; and Klason lignin, KL) in a two-stage tubular reactor (TS-TR) at 773–1223 K. The heating rate of lignin particle in the TS-TR was estimated at 102–104 K/s by solving the heat transfer equation. The pyrolytic behavior of lignin and the formation of products in the temperature rising process were predicted using a semi-detailed kinetic model consisting of 93 species and 406 reactions, and the predicted yields of 8 primary products (i.e., char, tar, CO, CO2, H2O, CH3OH, C2H6, and C3H6) were compared with experimental data for the critical evaluation. For EHL, the predicted yields of char and H2O were in good agreement with the experimental results at all temperatures. However, the numerical simulation overestimated tar yield and underestimated CO yield at high temperature probably due to a lack of the kinetic model of the tar cracking reaction. The predicted yields of CH3OH, C2H6, and C3H6 were close to the experimental values at high temperature by adding the detailed chemical kinetic model of the secondary vapor-phase reaction. Moreover, the model reproduced the experimental observation that among the three types of lignin the char yield increased in the order of EHL |
| 63. | Masaharu Tsuji, Keiko Uto, Hayashi Jun-Ichiro, Akihiko Yoshiwara, Synthesis of Flower-Like AuPd@SiO2 Nanoparticles with a Broad Light Extinction for Application to Efficient Dye-Sensitized Solar Cells, Particle and Particle Systems Characterization, 10.1002/ppsc.201700396, 2018.01, Flower-like AuPd alloy nanoparticles (NPs) are prepared by reducing a mixture of HAuCl4/H2PdCl4 in an aqueous solution. Transmittance electron microscope (TEM), TEM-energy dispersed X-ray spectroscopy, and X-ray diffraction data indicate that AuPd alloy NPs are composed of Pd rich core and Au rich shell. Crystal growth mechanism of ununiform AuPd alloy NPs is discussed in terms of oxidative etching by Cl-/O2. Even when AuPd alloy NPs are covered by SiO2 shells for the use of dye-sensitized solar cells (DSSCs), ununiform alloy structure of AuPd NPs is reserved after sintering at 450 °C. When 0.36-4.8 wt% of AuPd@SiO2 NPs are added to TiO2-N719-DSSCs, the photoconversion efficiency (PCE) is enhanced by 7-38% in comparison with that obtained without addition of metallic NPs. The enhancement of PCE by the addition of AuPd@SiO2 NPs is discussed in terms of near-field surface plasmon resonance (SPR) effect of metallic NPs and far-field light-scattering effect of large TiO2 aggregates formed by the addition of a small amount of distilled water into TiO2 pastes. On the basis of the short-circuit current density (Jsc) and the open-circuit voltage (Voc) changes upon the addition of AuPd@SiO2, the enhancement of PCE is attributed to synergy effects of far-field scattering of large TiO2 aggregates and near-field SPR of AuPd@SiO2 NPs.. |
| 64. | Yuki Furutani, Yuki Dohara, Shinji Kudo, Hayashi Jun-Ichiro, Koyo Norinaga, Theoretical Study on Elementary Reaction Steps in Thermal Decomposition Processes of Syringol-Type Monolignol Compounds, Journal of Physical Chemistry A, 10.1021/acs.jpca.7b09450, 122, 3, 822-831, 2018.01, This paper theoretically investigated a large number of reaction pathways and kinetics to describe the vapor-phase pyrolytic behavior of several syringol-type monolignol compounds that are derived from the primary pyrolysis of lignin: 1-(4-hydroxy-3,5-dimethoxyphenyl)prop-2-en-1-one (HDPP), sinapyl alcohol, 3-hydroxy-1-(4-hydroxy-3,5-dimethoxyphenyl)propan-1-one (HHDPP), 1-(4-hydroxy-3,5-dimethoxyphenyl)propane-1,3-diol (HDPPD), and syringol. The possible pyrolytic pathways involving unimolecular decomposition, addition, and abstraction reactions were investigated by comparing the energy barriers calculated at the B3LYP/6-311++G(d,p) level. In the proposed pathways, all syringol-type monolignols containing a side chain undergo its cleavage to form syringol through the formation of syringaldehyde or 4-vinylsyringol. Syringol is then converted into two products: (a) pyrogallol via the homolysis of the O-CH3 bond and hydrogenation or (b) guaiacol via addition of an H atom with a carbon bearing methoxyl group in syrignol and the subsequent demethoxylation. The pyrolytic pathways of pyrogallol are classified into two processes: (a) the concerted dehydrogenation of the two hydroxyl H atoms and the unimolecular decomposition to produce acetylene (C2H2), ethynol (C2HOH), and CO or (b) the displacement of an OH with H to produce catechol and resorcinol. Additionally, HDPP undergoes O-CH3 bond cleavage to form but-1-en-3-yne. The high-pressure limit rate constants for all the proposed elementary reaction steps were evaluated on the basis of transition state theory.. |
| 65. | M. Tsuji, T. Kawahara, K. Uto, J.-i. Hayashi, T. Tsuji, Photochemical removal of NO2 in air at atmospheric pressure using side-on type 172-nm Xe2 excimer lamp, International Journal of Environmental Science and Technology, 10.1007/s13762-018-2131-y, 2018.01. |
| 66. | Yuki Furutani, Koyo Norinaga, Shinji Kudo, Hayashi Jun-Ichiro, Tomoaki Watanabe, Current situation and future scope of biomass gasification in Japan, Evergreen, 4, 4, 24-29, 2017.12, In this study, we investigated current situation of biomass gasification plants in 5 cities (c.a. Murayama City, Chichibu City, Ueno Village, Oshu City and Yamaguchi City) in Japan, and make R&D policy proposals to expand the biomass gasification plants. Four cities have commonly promoted the efficient heat utilization such as snow melting, drying the wood and supplying hot water into mushroom bed and hot spring. However, heat utilization is limited in a small area because heat loss is generated during the long-distance transportation. In order to obtain energy forms suitable for the long-distance transportation, such as hydrogen gas and electricity, the R&D of biomass gasification with hydrogen production or combined with Solid Oxide Fuel Cell (SOFC) should be promoted in the future.. |
| 67. | Yuki Furutani, Yuki Dohara, Shinji Kudo, Hayashi Jun-Ichiro, Koyo Norinaga, Theoretical Study on the Kinetics of Thermal Decomposition of Guaiacol and Catechol, Journal of Physical Chemistry A, 10.1021/acs.jpca.7b08112, 121, 44, 8495-8503, 2017.11, The theoretical aspects of the development of a chemical kinetic model for guaiacol and catechol pyrolysis are presented to describe the pyrolysis behaviors of the individual lignin-derived components. The possible pyrolysis pathways involving both unimolecular and bimolecular decomposition were investigated by the potential energy surfaces (PES) calculated at CBS-QB3 level. The high-pressure limiting rate constants of each elementary reaction step were evaluated based on the transition state theory (TST) to determine the dominant pyrolysis pathways. The kinetic analysis results predicted the most favorable catechol unimolecular decomposition pathways, where catechol isomerization to 2-hydroxycyclohexa-2,4-dien-1-one occurred via migration of the hydroxyl H atom, followed by decomposition into 1,3-cyclobutadiene, acetylene, and CO. In the case of the bimolecular reaction of catechol, a hydrogen radical is coupled to the carbon atom in the benzene ring, leading to the formation of phenol and a hydroxyl radical through dehydroxylation. On the other hand, guaiacol is likely to form catechol and phenol via the O-CH3 homolysis and coupling of a hydrogen radical to the carbon atom with the methoxyl group, respectively.. |
| 68. | U. P.M. Ashik, W. M.A. Wan Daud, Hayashi Jun-Ichiro, Governance of the porosity and of the methane decomposition activity sustainability of NiO/SiO2 nanocatalysts by changing the synthesis parameters in the modified Stöber method, Comptes Rendus Chimie, 10.1016/j.crci.2017.06.007, 20, 9-10, 896-909, 2017.09, Nanoscience and nanotechnology present ubiquitous possibilities in almost any scientific field because of property enhancement occurring in nanoparticles with unique size and shape. The physicochemical characteristics of nanoparticles play an imperative role in their prospective applications. This article reports an in-depth study on the variance of the physicochemical characteristics, the methane decomposition activity, and the sustainability of nano-NiO/SiO2 (n-NiO/SiO2) catalysts with different preparation parameters. The influence of nickel/silicate ratio, octadecyltrimethoxysilane (C18TMS)/tetraethylorthosilicate (TEOS) ratio, and of different solvents was investigated. The characteristic features of the prepared catalysts were inspected using N2 adsorption–desorption measurements, X-ray diffraction, hydrogen temperature-programmed reduction, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, and methane cracking catalytic activity in a fixed bed reactor. Methane decomposition activity was evaluated by measuring the instantaneous hydrogen production (vol %) and carbon yield (%) at the end of the examination. The results showed that C18TMS has extensively improved the microporosity of the material, hence resulting in the improvement of the catalytic performance. The microporosity of the n-NiO/SiO2 catalyst has increased from 10.7% to 26.8% when the quantity of C18TMS was increased from 0 to 1.2 mL in the synthesis mixture. Catalysts prepared with a maximum quantity of C18TMS and a minimum quantity of tetraethylorthosilicate exhibited a minimum activity loss of 17.46%.. |
| 69. | Shi Chao Qi, Lu Zhang, Shinji Kudo, Koyo Norinaga, Hayashi Jun-Ichiro, Theoretical Study on Hydrogenolytic Cleavage of Intermonomer Linkages in Lignin, Journal of Physical Chemistry A, 10.1021/acs.jpca.7b00602, 121, 15, 2868-2877, 2017.04, Hydrogenolysis is an important approach for depolymerization of lignin, which provides attractive new sustainable platforms of fuels, chemicals, and materials. The theory of lignin hydrogenolysis is, however, still unsound, which limits the development of this approach and causes inconsistencies among experimental studies. In this paper, density functional theory is employed to investigate the initial hydrogenolytic cleavages of recognized five different types of interaromatic unit linkages of lignin, assuming the presence of hydrogen free radicals. The relative free energies of reactant complexes, reaction free energy changes, and rate constants for candidate reactions are calculated comprehensively at 298-538 K. On the basis of the results of calculation and a rapid equilibrium hypothesis, the major reaction channel is decided for each linkage, and its kinetics is assessed. It is concluded that the hydrogenolysis occurs at β-O-4 ether, diphenyl ether 4-O-5′, and β-1′ diphenylmethane linkages instantaneously if these are accessible to hydrogen free radicals, while β-5 phenylcoumaran and β-β′ pinoresinol linkages are virtually inert to hydrogenolysis. (Graph Presented).. |
| 70. | Masaharu Tsuji, Keiko Uto, Tetsuo Nagami, Akiko Muto, Hideoki Fukushima, Hayashi Jun-Ichiro, Synthesis of Carbon-Supported Pt–YOx and PtY Nanoparticles with High Catalytic Activity for the Oxygen Reduction Reaction Using a Microwave-based Polyol Method, ChemCatChem, 10.1002/cctc.201601479, 9, 6, 962-970, 2017.03, Carbon-supported PtY alloy nanoparticles were prepared as oxygen reduction reaction (ORR) catalysts by reducing a mixture of cis-[Pt(NH3)2(NO2)2] or Pt(C5H7O2)2 and Y(CH3COO)3⋅4 H2O in ethylene glycol (EG) with microwave (MW) heating. Microstructure and composition analyses of products by using TEM, TEM–energy-dispersive X-ray spectroscopy (EDS), XRD, X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma atomic emission spectroscopy (ICP-AES) data showed that Pt–YOx/C (Y/Pt=0.11–0.75) catalysts involving amorphous yttrium oxide were formed as major products. When the YOx component in the catalysts was removed by using HNO3 treatment, Pt99.1–99.6Y0.4–0.9/C alloy catalysts with low Y contents remained. Higher ORR activity was shown by Pt–YOx/C and PtY/C catalysts than by Pt–Y(OH)3/C, Pt–YOx/C, or PtY/C catalysts prepared by using other conventional chemical reduction methods and thermal treatment methods under a H2/Ar or Ar atmosphere. The mass activity (MA) and surface specific activity (SA) of the best Pt99.5Y0.5/C catalyst, MA=245 A gPt −1 and SA=711 μA cmPt −2, were equal to or higher than those of the commercially used Pt86Co14/C catalyst, MA=245 A gPt −1 and SA=512 μA cmPt −2. The major reasons for the high ORR activity of these Pt–YOx/C and PtY catalysts are discussed. These Pt99.1–99.6Y0.4–0.9/C alloy catalysts prepared by using acid treatment are new and promising catalysts for use in proton exchange membrane fuel cells (PEMFCs).. |
| 71. | Yuki Furutani, Shinji Kudo, Hayashi Jun-Ichiro, Koyo Norinaga, Theoretical study on reaction pathways leading to CO and CO2 in the pyrolysis of resorcinol, Journal of Physical Chemistry A, 10.1021/acs.jpca.6b05168, 121, 3, 631-637, 2017.03, Possible pathways for the pyrolysis of resorcinol with the formation of CO and CO2 as final products were proposed and evaluated using ab initio calculations. Our experimental study revealed that large quantities of CO2 are generated in the pyrolysis of 1,3-dihydroxybenzene (resorcinol), while the pyrolysis of the dihydroxybenzene isomers 1,2-dihydroxybenzene (catechol) and 1,4-dihydroxybenzene (hydroquinone) produces little CO2. The fate of oxygen atoms in catechol and hydroquinone was essentially the formation of CO. In the proposed pathways, the triplet ground state m-benzoquinone was generated initially from simultaneous cleavage of the two O-H bonds in resorcinol. Subsequently, the direct cleavage of a C-C bond of the m-benzoquinone diradical yields 2-oxidanylcyclopenta-2,4-dien-1-yl-methanone, which can be converted via two channels: release of CO from the aldehyde radical group and combination of the ketone radical and carbon atom in the aldehyde radical group to form the 6-oxabicyclo[3.2.0]hepta-2,4-dien-7-one, resulting in the release of CO2. Potential energy surfaces along the proposed reaction pathways were calculated employing the CBS-QB3 method, and the rate constants at the high-pressure limit were also evaluated based on transition-state theory to assess the feasibility of the proposed reaction pathways.. |
| 72. | U. P.M. Ashik, W. M.A. Wan Daud, Hayashi Jun-Ichiro, A review on methane transformation to hydrogen and nanocarbon Relevance of catalyst characteristics and experimental parameters on yield, Renewable and Sustainable Energy Reviews, 10.1016/j.rser.2017.03.088, 76, 743-767, 2017.01, Co-synthesis of hydrogen and nanocarbon via methane cracking is a single step technique which meets ever growing need of greenhouse gas (GHG) free energy. Additionally, as produced multifunctional nano-carbon that have a variety of technological applications reduces the process cost. This review is intended to provide a critical and wide-ranging assessment of impact of metal catalyst characteristics and methane decomposing parameters on hydrogen and nanocarbon yield, as well as the alteration of characteristic properties of as-produced nanocarbon. The major factors influencing thermocatalytic decomposition of methane (TCD) includes catalyst support, porosity, surface area, particle size, metal loading, calcination temperature, feed flow rate, partial pressure, and reaction temperature. Literature survey emphasizes that higher temperature and partial pressure together with lower feed flow is the reliable experimental condition to yield high purity hydrogen. Furthermore, initial catalytic activity resembles to the chemical structure of the catalyst and long term activity corresponds to the physical characteristics of catalyst. The structural features of as-produced nanocarbon have inevitable association with catalytic characteristics, such as textural supporters, particle size and material dispersion by physical interactions or chemical interaction. The interaction of metal and support results in modification of electronic properties of metal particles and subsequently influence their catalytic characteristics. In addition to investigation of one-factor-at-a-time experiments, the latest studies with Design of Experiment are also thoroughly reviewed, which analyze the influence of each process variables and their interactions simultaneously. The manuscript, then, extended to the microscopic level understandings on TCD for synthesis of nanocarbon and hydrogen via computational study in the finishing section.. |
| 73. | Lu Zhang, Shi Chao Qi, Keita Iwanaga, Kazuhiro Uemura, Li Xin Zhang, Shinji Kudo, Hayashi Jun-Ichiro, Kenji Furuya, Koyo Norinaga, An approach for on-line analysis of multi-component volatiles from coal pyrolysis with Li+-attachment ionization mass spectrometry, Fuel Processing Technology, 10.1016/j.fuproc.2016.12.001, 158, 141-145, 2017.01, Ion-attachment mass spectrometry (IAMS) is a technique used for measuring easily ionized organic compounds in a non-fragmenting mode by softly attaching a Li+or another type of alkaline ion to the gaseous molecule. In this study, a prototype device for Li+IAMS is developed for real-time quantitative monitoring of the vapor produced from thermochemical conversion of coal. Simulated tar vapor containing a suite of aromatics and the real vapor produced from the pyrolysis of coal are monitored by IAMS with a Li+source. It is confirmed that both the simulated and real vapors are ionized without undergoing fragmentation and the sensitivities of these detected aromatic molecules are similar to one another. In addition, when the feeding rate of the coal sample is changed from 0.5 to 1.0 g/min, the peak intensities increase nearly twice as much. These results show the possibility of applying IAMS to the quantitatively monitoring of coal-derived volatiles.. |
| 74. | Shi Chao Qi, Hayashi Jun-Ichiro, Shinji Kudo, Lu Zhang, Catalytic hydrogenolysis of kraft lignin to monomers at high yield in alkaline water, Green Chemistry, 10.1039/c7gc01121k, 19, 11, 2636-2645, 2017.01, Inspired by the results of calculation on the basis of density functional theory and a semi-empirical method, we found an easy, robust, and efficient approach to solve the problem of folded lignin macromolecules, which is a key factor for impeding their breakdown into monomers by hydrogenolysis. Oxidation and hydrogenolysis, which appear to be independent and contradictory of each other in many past studies, were combined and successively performed in this study. Hydrogen peroxide was used to damage the strong intramolecular hydrogen bonds of kraft lignin efficiently, transforming the folded three-dimensional geometries of the lignin macromolecules into stretched ones in an alkaline aqueous medium. Following the pretreatment of stretching lignin molecules, catalytic hydrogenolysis was performed in the presence of a Ni catalyst supported by the ZSM-5 zeolite, reported by the authors. Because of more chemisorption sites of the stretched lignin macromolecules onto the catalyst surface and the remission of lignin re-polymerization/self-condensation, conversion of the kraft lignin into oil reached 83 wt% lignin, 91 wt% which was accounted for by nine types of monomers. This study has thus demonstrated high yield monomer production from lignin dissolved in aqueous media.. |
| 75. | Shi Chao Qi, Lu Zhang, Hisahiro Einaga, Shinji Kudo, Koyo Norinaga, Hayashi Jun-Ichiro, Nano-sized nickel catalyst for deep hydrogenation of lignin monomers and first-principles insight into the catalyst preparation, Journal of Materials Chemistry A, 10.1039/c6ta08538e, 5, 8, 3948-3965, 2017.01, This paper reports, for the first time, complete arene hydrogenation of phenolic compounds as lignin monomers over a non-noble metal catalyst supported by a general material. A type of nano-sized Ni catalyst was prepared in ethanol and in situ supported by ZSM-5 zeolite through general borohydride reduction of Ni2+ to Ni0, but with application of a simple ligand, pyridine. This catalyst showed an activity so high as to completely or near completely hydrogenate the aromatic rings of phenol and its twelve derivatives as potential lignin monomers at 180 °C. The activity was clearly higher than that of another type of conventional Ni catalyst prepared in the absence of pyridine. Analyses of the catalysts by TEM/EDS, XPS, XAFS and others demonstrated that pyridine had crucial roles in selective formation of nano-sized Ni and maintenance of its activity by appropriate interaction with the support. This paper also shows our theoretical approach to the mechanism of the borohydride reduction. First-principles calculations based on density functional theory (DFT) revealed the reaction pathway from Ni2+ to Ni0 and the role of pyridine, which was validated by some experimental facts. The DFT calculations also explain the variety of reactivities of the lignin monomers, which are strongly influenced by their molecular electrostatic and steric nature.. |
| 76. | Shinji Kudo, Nozomi Goto, Jonathan Sperry, Koyo Norinaga, Hayashi Jun-Ichiro, Production of Levoglucosenone and Dihydrolevoglucosenone by Catalytic Reforming of Volatiles from Cellulose Pyrolysis Using Supported Ionic Liquid Phase, ACS Sustainable Chemistry and Engineering, 10.1021/acssuschemeng.6b02463, 5, 1, 1132-1140, 2017.01, This paper presents a novel method for continuous production of a biomass-derived platform chemical, levoglucosenone (LGO), from cellulose without its pretreatment or use of solvent. First, cellulose is pyrolyzed, and then the volatiles are reformed over a catalyst consisting of a type of ionic liquid supported over porous char. The ionic liquid, having a moderate hydrogen-bond basicity, performs well in the dehydrative conversion of levoglucosan (LGA) and anhydrosugar oligomers in the volatiles to LGO at 275 °C. The catalytic reforming to LGO is highly selective, and consequently, the yield of LGO is determined mainly by the pyrolysis conditions that produce the LGO precursors. The highest LGO yield we obtained was 31.6% on a cellulose carbon basis (24.6 wt %) with fast pyrolysis that produced more precursors than the slow one. Furthermore, the reaction system is applicable to the production of dihydrolevoglucosenone (DLGO), a promising biobased alternative to dipolar aprotic solvents. Addition of hydrogen in carrier gas and a hydrogenation catalyst in the catalytic bed enables the production of DLGO, although improvement in hydrogenation selectivity is required in the present reforming system.. |
| 77. | Ayuko Kitajou, Shinji Kudo, Hayashi Jun-Ichiro, Shigeto Okada, Synthesis and electrochemical properties of Fe3C-carbon composite as an anode material for lithium-ion batteries, Electrochemistry, 10.5796/electrochemistry.85.630, 85, 10, 630-633, 2017.01, Novel Fe3C carbon composite was proposed as new low cost and low environmental impact anode for Li-ion battery. Although the delithiated capacity of Fe3C without AB were 100mAhg-1 in the first cycle at a rate of 7mAg-1, that of Fe3C with AB was improved to 230mAhg-1 at a rate of 50mAg-1. Moreover, nanoparticle-Fe3C carbon composite including a relatively high-purity Fe3C could be obtained from α-Fe2O3 and ion-exchange resin. The best initial delithiated capacity more than 320mAhg-1 at a rate of 50mAg-1 and improved anode performance were obtained in the Fe3C-carbon composite sintered at 650°C.. |
| 78. | Cheng Yi Li, Li Xin Zhang, Shinji Kudo, Hayashi Jun-Ichiro, Koyo Norinaga, Toward low-temperature coal gasification Experimental and numerical studies of thermochemical coal conversion considering the interactions between volatiles and char particles, KONA Powder and Particle Journal, 10.14356/kona.2017008, 2017, 34, 70-79, 2017.01, A novel triple-bed combined circulating fluidized-bed (TB-CFB) coal gasifier, consisting of a downer (pyrolyzer), a bubbling fluidized bed (gasifier), and a riser (combustor) was proposed for realizing low-temperature coal gasification. Several key thermochemical reactions were extracted from those expected in the downer unit: the reforming of refractory tar in both the gas phase and over the char surface, and the steam gasification of the nascent char. This review highlights our recent progress, both experimental and numerical, in studies of thermochemical coal conversion including the various reaction processes, by employing a drop-tube reactor that well approximates the reaction environment in a downer reactor. This discussion can be utilized in designing TBCFBs and optimizing their operation.. |
| 79. | Yong Huang, Yalun Hu, Hayashi Jun-Ichiro, Yunming Fang, Interactions between Volatiles and Char during Pyrolysis of Biomass Reactive Species Determining and Reaction over Functionalized Carbon Nanotubes, Energy & Fuels, 10.1021/acs.energyfuels.6b00725, 30, 7, 5758-5765, 2016.07, This paper investigated the interactions between volatiles and char during pyrolysis of biomass with an emphasis on those between the reactive compounds in volatiles and the oxygen-containing functional groups in char. On the basis of a comparative study on the products from biomass pyrolysis with and without heavy oil (HO) recycling, which represented a maximization and minimization of the volatile-char interactions, respectively, levoglucosan (LG) was selected as the typical reactive compound in the volatiles. The interactions between LG and functionalized graphitized multiwalled carbon nanotubes with hydroxyl and carboxyl groups (HGMCN and CGMCN, respectively) as char models were surveyed at 300, 350, 400, and 450 °C. The results show that temperature plays an important role in the interactions between LG and GMCNs. HGMCN interacted with LG only at 400 °C, while the LG-CGMCN interactions started at 400 °C and intensified at 450 °C with a significant increase in gas yield. The GC-MS analyses indicated that the liquid products from the LG-GMCNs interactions were predominant in furfural and 5-methyl-2-furancarboxaldehyde.. |
| 80. | Chengyi Li, Srinivas Appari, Ryota Tanaka, Kyoko Hanao, Yeonkyung Lee, Shinji Kudo, Jun-ichiro Hayashi, Vinod M Janardhanan, Hiroaki Watanabe, Koyo Norinaga, A CFD Study on the Reacting Flow of Partially Combusting Hot Coke Oven Gas in a Bench Scale Reformer, Fuel, 159, 590-598, 2015.07. |
| 81. | Appari S., Tanaka R., Li C., Kudo S., Hayashi J.-i., Janardhanan V.M., Watanabe H., Norinaga K., Predicting the temperature and reactant concentration profiles of reacting flow in the partial oxidation of hot coke oven gas using detailed chemistry and a one-dimensional flow model, 10.1016/j.cej.2014.12.041, 82-90, 2015.05. |
| 82. | Karnowo, Shinji Kudo, Aska Mori, Zayda Faizah Zahara, Koyo Norinaga, Jun-ichiro Hayashi, Modification of Reactivity and Strength of Formed Coke from Victorian Lignite by Leaching of Metallic Species, ISIJ International, 55, 765-774, 2015.04. |
| 83. | Narumon Thimthong, Srinivas Appari, Ryota Tanaka, Keita Iwanaga, Shinji Kudo, Jun-ichiro Hayashi, Tetsuya Shoji, Koyo Norinaga, Kinetic Modeling of Non-Catalytic Partial Oxidation of Nascent Volatiles Derived from Fast Pyrolysis of Woody Biomass with Detailed Chemistry, Fuel Processing Technology, 134, 159-165, 2015.02. |
| 84. | Shinji Kudo, Aska Mori, Ryosuke Soejima, Karnowo, Seiji Nomura, Yusuke Dohi, Koyo Norinaga, Jun-ichiro Hayashi, Preparation of Coke from Hydrothermally Treated Biomass in Sequence of Hot Briquetting and Carbonization, ISIJ International, 54, 2461-2469, 2014.12. |
| 85. | Srinivas Appari, Ryota Tanaka, Chengyi Li, Shinji Kudo, Jun-ichiro Hayashi, Vinod Jadardhanan, Hiroaki Watanabe, Koyo Norinaga, Predicting the Temperature and Reactant Concentration Profiles of Reacting Flow in the Partial Oxidation of Coke Oven Gas using Detailed Chemistry and a One-dimensional Flow Model, Chemical Engineering Journal, 266, 82-90, 2014.12. |
| 86. | Zayda Faizah Zahara, Karnowo, Shinji Kudo, Koyo Norinaga, Jun-ichiro Hayashi, Characteristics of Hydrothermal Treatment of Woody Biomass and Features of Upgraded Solid, Proc. 4th Asian Conf. Innovative Energy & Environmental Chem. Eng., Yeosu, 24-29, 2014.11. |
| 87. | Kazuhiro Uemura, Srinivas Appari, Shinji Kudo, Jun-ichiro Hayashi, Hisahiro Einaga, Koyo Norinaga, In-situ reforming of the volatiles from fast pyrolysis of ligno-cellulosic biomass over zeolite catalysts for aromatic compound production, Fuel Processing Technology, 136, 73-78, 2014.11. |
| 88. | Atsushi Takahara, Higaki Yuji, Kaoru Hatate, Tastuya Ishikawa, Toshimasa Takanohashi, Jun-ichiro Hayashi, Adsorption and Desorption Behavior of Asphaltene on Polymer Brush Immobilized Surfaces, ACS Applied Materials & Interfaces, 6, 20385-20389, 2014.11. |
| 89. | Narumon Thimthong, Ryota Tanaka, Srinivas Appari, Shinji Kudo, Jun-ichiro Hayashi, Koyo Norinaga, An Application of CFD for Simulating Biomass Pyrolysis in a Moving-Bed Reactor, Proc. 4th Asian Conf. Innovative Energy & Environmental Chem. Eng., Yeosu, 304-309, 2014.11. |
| 90. | Shingo Nishioka, Shinji Kudo, Yuka Takashima, Yasuyo Hachiyama, Koyo Norinaga, Jun-ichiro Hayashi, Hydrothermal Conversion of Lignin to Monomeric Phenols and Fuel Gas Using Alkaline Aqueous Solution, Proc. 4th Asian Conf. Innovative Energy & Environmental Chem. Eng., Yeosu, 56-61, 2014.11. |
| 91. | Yong Huang, Hajime Sakamoto, Shinji Kudo, Koyo Norinaga, Jun-ichiro Hayashi, Pyrolysis of Lignite with Internal Recycling and Conversion of Oil, Energy Fuels, 28, 7285-7293, 2014.10. |
| 92. | Karnowo, Zayda Faizah Zahara, Shinji Kudo, Koyo Norinaga, Jun-ichiro Hayashi, Leaching of alkali and alkaline earth metallic species from rice husk with bio-oil from its pyrolysis, Energy Fuels, 28, 6459-6466, 2014.10. |
| 93. | Lei Bai, Karnowo, Shinji Kudo, Koyo Norinaga, Yong-gang Wang, Jun-ichiro Hayashi, Kinetics and Mechanism of Steam Gasification of Char from Hydrothermally Treated Woody Biomass, Energy Fuels, 28, 7133-7139, 2014.10. |
| 94. | Huamei Yang, Srinivas Appari, Shinji Kudo, Jun-ichiro Hayashi, Satoshi Kumagai, Koyo Norinaga, Chemical structures and primary pyrolysis characteristics of lignins obtained from different preparation methods, J. Japan Inst. Energy , 93, 986-994, 2014.10. |
| 95. | Tomoyuki Oike, Shinji Kudo, Hua Yang, Junya Tahara, Hyun-Seok Kim, Ryo Koto, Koyo Norinaga, Jun-ichiro Hayashi, Sequential Pyrolysis and Potassium-Catalyzed Steam-Oxygen Gasification of Woody Biomass in a Continuous Two-Stage Reactor, Energy Fuels, 28, 6407-6418, 2014.09. |
| 96. | Hyun-Seok Kim, Shinji Kudo, Koyo Norinaga, Jun-ichiro Hayashi, Preparation and Steam Gasification of Fe-ion Exchanged Lignite Prepared with Iron Metal, Water, and Pressurized CO2, Energy Fuels, 2014.08. |
| 97. | Shinji Kudo, Yasuyo Hachiyama, Hyun-Seok Kim, Koyo Norinaga, Jun-ichiro Hayashi, Examination of kinetics of non-catalytic steam gasification of biomass/lignite chars and its relationship with the variation of pore structure, Energy Fuels, 28, 5902-5908, 2014.08. |
| 98. | Koyo Norinaga, Huamei Yang, Ryota Tanaka, Srinivas Appari, Keita Iwanaga, Yuka Takashima, Shinji Kudo, Tetsuya Shoji, Jun-ichiro Hayashi, A mechanistic study on the reaction pathways leading to benzene and naphthalene in cellulose vapor phase cracking, Biomass Bioenergy, 69, 144-154, 2014.08. |
| 99. | Dawei Liu, Yun Yu, Jun-ichiro Hayashi, Behdad Moghtaderi, Hongwei Wu, Contribution of dehydration and depolymerization reactions during the fast pyrolysis of various salt-loaded celluloses at low temperatures, Fuel, 136, 62-68, 2014.07. |
| 100. | Shi-Chao Qi, Lu Zhang, Xian-Yong Wei, Hayashi Jun-ichiro, Zhi-Min Zong, Lu-Lu Guo, Deep hydrogenation of coal tar over a Ni/ZSM-5 catalyst, RSC Advances, 10.1039/c3ra47701k, 4, 17105-17109, 2014.03, We have developed a Ni/ZSM-5 catalyst and utilised it to completely hydrogenate a series of condensed arenes, including naphthalene, anthracene and phenanthrene, under relatively mild conditions. The yields of decalin, perhydroanthracene and perhydrophenanthrene reached 100%, 98.8% and 25.8%, respectively. By analyzing the isomer distribution of the perhydroarenes, we proposed a mechanism of biatomic hydrogen transfer, which was further proven via the hydro- genation of 9,10-diphenylanthracene. Through hydrotreatment over the Ni/ZSM-5 catalyst, both high-temperature coal tar rich in condensed arenes and low-temperature coal tar mixing arenes with alkanes were greatly upgraded. The majority of arenes in the coal tars were deeply and even completely hydrogenated, which may open up a route for further processing and application of coal tar as clean fuels.. |
| 101. | Ahu-Sheng Yang, Zhi-Min Zong, Bo Chen, Yun-Peng Zhao, Xing Fan, Xian-Yong Wei, Hayashi Jun-ichiro, Thermal Dissolution of Sgengli Lignite in Ethyl Acetate, Int. J. Oil, Gas and Coal Technology, 7, 3, 308-321, 2014.01. |
| 102. | Kudo Shinji, Yasuyo Hachiyama, Yuka Takashima, Junya Tahara, Idesh Saruul, Koyo Norinaga, Hayashi Jun-ichiro, Catalytic Hydrothermal Reforming of Lignin in Aqueous Alkaline Medium, Energy & Fuels, 10.1021/ef401557w, 28, 1, 76-85, 2014.01, This paper proposes catalytic hydrothermal reforming (CHTR) for producing substitute natural gas (SNG) directly from a lignin in aqueous alkaline media, which can fully dissolve the lignin but stabilize it, lowering the reactivity toward water. Among catalysts preliminarily tested, activated-carbon-supported ruthenium (Ru/AC) catalysts showed the highest activity in terms of reduction of the total organic carbon concentration (TOC) in the aqueous solution. CHTR of a lignin was performed employing a 5000 ppm TOC solution of 0.1 M Na2CO3 in a continuous reactor. The presence of Na2CO3 in the solution enabled delivery of the lignin, which is poorly soluble in water, to the reactor as well as suppression of char formation during CHTR. A Ru/AC showed its ability to maintain 98.6% conversion of the lignin at 350 °C even under the alkaline environment for a duration of at least 10 h, with colorless effluent liquid containing 70 ppm TOC of organic carbon. A low content of Ru in the Ru/AC resulted in an insufficient yield of gas because of the deposition of a portion of the lignin as coke over the catalyst, while 20 wt % Ru was enough for the full conversion into gas composed mainly of CH4, with cold gas efficiency (CGE) of 100.4% on a higher heating value (HHV) basis. The resulting aqueous solution of Na2CO3 was ready to be reused for CHTR after removal of carbonate ions derived from the lignin by aeration.. |
| 103. | Hayashi Jun-ichiro, Kudo Shinji, Hyun-Seok Kim, Koyo Norinaga, Sou Hosokai, Koichi Matsuoka, Sou Hosokai, Low temperature Gasification of Biomass and Lignite: Consideration of Key Thermochemical Phenomena, Rearrangement of Reactions, and Reactor Configuration, Energy & Fuels, 10.1021/ef401617k , 28, 1, 4-21, 2014.01, This paper discusses gasification of solid fuels, such as biomass and lignite, at temperatures well below 1000 °C, which potentially realizes a loss of chemical energy (LCE) smaller than 10% but encounters difficulty in fast and/or complete solid-to-gas conversion in conventional reactor systems. First, key thermochemical and catalytic phenomena are extracted from complex reactions involved in the gasification. These are interactions between intermediates (i.e., volatiles and char), catalysis of inherent and extraneous metallic species, and very fast steam gasification of nascent char. Second, some ways to control the key phenomena are proposed conceptually together with those to rearrange homogeneous/heterogeneous reactions in series/ parallel. Third, implementation of the proposed concepts is discussed assuming different types of gasifiers consisting of a single- fluidized bed, dual-fluidized bed, triple-bed circulating fluidized bed, and/or fixed (moving) bed. The triple-fluidized bed can attain gasification with a LCE as small as 10% by introducing enhancement and/or elimination of the key phenomena and another way to recuperate heat from gas turbine and/or fuel cells (i.e., power generators in gasification combined cycles) into chemical energy of fuel gas. A particular type of fixed-bed gasifier is proposed, which is separated from a pyrolyzer to realize not only control of the key phenomena but also temporal/spatial rearrangement of exothermic and endothermic reactions. This type of gasifier can make a LCE smaller than 4%. Even a conventional single-fluidized bed provides simple and effective gasification, when tar-free/reactive char is used as the fuel instead of parent the one and contributes to a novel integrated gasification fuel cell combined cycles with a theoretical electrical efficiency over 80%.. |
| 104. | Chihiro Fushimi, Masanori Ishizuka, Guoqing Guan, Yoshizo Suzuki, Koyo Norinaga, Hayashi Jun-ichiro, Atsushi Tsutsumi, Hydrodynamic Behavior of Binary Mixture of Solids in a Triple-Bed Combined Circulating Fluidized Bed with High Mass Flux, Advanced Powder Technology, 10.1016/j.apt.2013.06.007, 25, 1, 379-388, 2014.01, Flow behaviors of binary mixture of silica sand and nylonshot (coal char substitute) were investigated in a triple-bed circulating fluidized bed (TBCFB) as a cold model of coal gasifier. The TBCFB consisted of a downer (/ 0.1 m 6.5 m), a bubbling fluidized bed (0.75 m 0.27 m 1.9 m), a riser (0.1 m 16.6 m) and a gas-sealing bed (GSB, / 0.158 m 5 m). The initial fraction of the nylonshot in the solid mixture (Xnylon,i) was 15.4 and 30% on mass and volume bases, respectively, or otherwise, 30.7 and 50%. The maximum solids mass flux (Gs) at Xnylon,i of 15.4 and 30.7 wt% were 394 and 349 kg/ m2 s, respectively, when the gas velocity in the riser (Ugr) was 10 m/s. Apparent solids holdups of silica sand and nylonshot were calculated separately from the static pressure gradient across the riser and the downer. The results showed possibility of large-mass-flux circulation of char in the gasifier, which plays a significant role in decomposition of tar from pyrolysis as the primary step of gasification. A newly developed pressure balance model successfully predicted Gs of the binary mixtures in TBCFB.. |
| 105. | Nozomu Sonoyama, Hayashi Jun-ichiro, Characterisation of coal and biomass based on kinetic parameter distributions for pyrolysis, Fuel, 10.1016/j.fuel.2012.04.023, 114, 206-215, 2013.12, We performed pyrolysis analyses of various biomasses and biomass-derived materials using a thermo- gravimetry device and a wire-mesh reactor. Kinetic parameters, which were a frequency factor and an activation energy, were derived based on a distributed activation energy model. We validated the predic- tion of thermogravimetric curves calculated using the kinetic parameters in the case of rapid pyrolysis of biomass having the least interaction between particles and volatiles. Unlike coal, the kinetic parameters of the samples changed markedly with progression of pyrolysis. We estimated that the low activation energy in the initial step was caused by hydration and the volatilisation of lighter components. Some bio- mass samples showed a decrease in both the frequency factor and activation energy during pyrolysis. Changes in the chemical structures of xylan and cellulose from cyclic aliphatic units to aromatic units, accompanying amorphism, softening, or melting of part of the solid phase in some cases, caused a decrease in kinetic parameters during pyrolysis. Both the frequency factor and activation energy of all biomass samples increased in the final stages, which was considered to be the result of char forming by carbonisation. Analysing in detail the changes in kinetic parameters provided information on the behaviour of the volatilisation, the change in solid state, and the extent of char structural development.. |
| 106. | Shi-Chao Qi, Xian-Yong Wei, Zhi-Min Zong, Hayashi Jun-ichiro, Xin-Hua Yuan, Lin-Bing Sun, A Highly Active Ni/ZSM-5 Catalyst for Complete Hydrogenation of Polymethylbenzenes, ChemCatChem, 10.1002/cctc.201300547, 5, 3543-3547, 2013.12. |
| 107. | Koichi Matsuoka, Sou Hosokai, Yoshishige Kato, Koji Kuramoto, Yoshizo Suzuki, Koyo Norinaga, Hayashi Jun-ichiro, Promoting gas production by controlling the interaction of volatiles with char during coal gasification in a circulating fluidized bed gasification reactor, Fuel Processing Technology, 10.1016/j.fuproc.2013.07.017, 116, 308-316, 2013.11, A novel circulating fluidized bed (CFB) gasifier, which consists of a downer and two bubbling fluidized beds, was developed. Coal is continuously pyrolyzed in the downer and the resultant char is sent to the bubbling bed gasifier for steam gasification while evacuation of the volatiles avoids the char–volatile interactions. Any ungasified char is transferred from the gasifier to the bubbling bed combustor, where it is either completely combusted or partially combusted and then recycled to the downer. Steam gasification was successfully performed in the absence of pyrolysis-derived volatiles, which strongly inhibit gasification. The recycling of the partially combusted char greatly increased its concentration in the downer thereby enhancing the reforming of the volatiles, in particular that of tar over that of char, and the resultant gas formation. The total yield of gases from the downer and bubbling bed gasifier was 45% higher than that obtained under direct feeding of the coal into the bubbling bed gasifier and full combustion of the char, i.e., with steam gasification of char in the presence of volatiles and subsequent reforming over char at a much lower concentration.. |
| 108. | Aska Mori, Mutia Dewi Yuniati, Anggoro Tri Mursito, Kudo Shinji, Koyo Norinaga, Moriyasu Nonaka, Tsuyoshi Hirajima, Hyun-Seok Kim, Hayashi Jun-ichiro, Preparation of Coke from Indonesian Lignites by a Sequence of Hydrothermal Treatment, Hot Briquetting and Carbonization, Energy & Fuels, dx.doi.org/10.1021/ef4016558 , 27, 11, 6607-6616, 2013.11, Production of coke from lignites was studied in continuation of a previous study that demonstrated effectiveness of a sequence of hot briquetting and carbonization on preparation of high strength coke from a lignite. Cokes were prepared from four Indonesian lignites with or without pretreatments such as hydrothermal treatment (HT) at 200−300 °C, acid washing (AW), and a combination of them (HT−AW). The hot briquetting of the raw lignites at temperature and mechanical pressure of 200 °C and 128 MPa, respectively, enabled cokes to be produced with a tensile strength (TS) of 7−22 MPa. The pretreatments, AW and HT at 200 °C (HT200), increased TSs of resulting cokes to 18−24 and 13−36 MPa, respectively. A sequence of HT200 and AW further increased TSs of cokes to 27−40 MPa. AW and HT200 modified the macromolecular structure of the lignites by different mechanisms. AW removed alkali and alkaline earth metallic species that played roles of cross-links in the macromolecular network, while HT200 rearranged macromolecules physically. Both HT and AW enhanced plasticization and then deformation/coalescence of lignite particles during the briquetting, which formed high strength briquettes. There were strong correlations between TS of coke and that of briquette and also between TS and bulk density of coke from the individual lignites.. |
| 109. | Li-xin Zhang, Toru Matsuhara, Kudo Shinji, Hayashi Jun-ichiro, Koyo Norinaga, Rapid pyrolysis of brown coal in a drop-tube reactor with co-feeding of char as a promoter of in situ tar reforming, Fuel, 10.1016/j.fuel.2011.12.030, 112, 681-686, 2013.10, A Victorian brown coal (Loy Yang, LY) was co-fed with char prepared from the same coal in an atmospheric drop-tube reactor (DTR) at 900 and 950 °C in the presence of 50% steam to study in situ reforming of tar derived from rapid pyrolysis of brown coal over a char surface. Two different chars were prepared, including devolatilised LY at 800 °C under nitrogen flow (LYC, surface area 524 m2/g) and LYC gasified with steam at 900 °C (GLYC, surface area 734 m2/g). The concentrations of chars in the blended samples varied from 50% to 85% on a carbon basis. The yield of tar derived from LY (no char was blended) was 4.2 wt.% at 900 °C and particle residence time around 3–4 s. The yield decreased with increasing char concentration, and was 0.5 wt.% at a GLYC concentration of 85% at 900 °C. Tar conversion over GLYC was more extensive than that over LYC and occurred more significantly at a higher temperature. Increasing the feeding rate of sample particles enhanced tar reforming, suggesting that solid hold-up was an important factor determining tar conversion characteristics. Liquid chromatography (LC) showed that the major components of heavy tar included typical polycyclic aromatic hydrocarbons (PAHs) ranging from three-membered rings (acenaphthylene) to seven-membered rings (coronene).. |
| 110. | Hyun-Seok Kim, Kudo Shinji, Keisuke Tahara, Yasuyo Hachiyama, Hua Yang, Koyo Norinaga, Hayashi Jun-ichiro, Detailed Kinetic Analysis and Modeling of Steam Gasification of Char from Ca-Loaded Lignite, Energy & Fuels, dx.doi.org/10.1021/ef401688h, 27, 10, 6617-6631, 2013.10, A kinetic model of steam gasification of Ca-loaded lignite char has been proposed through the analysis of 41 sets of kinetic data obtained by thermogravimetry with different combinations of Ca concentration, temperature, and partial pressures of hydrogen and steam. The model quantitatively describes the change with time of the char conversion over its entire range by assuming progress of non-catalytic gasification and two different types of Ca-catalyzed gasification (Type-1 and Type-2) in parallel, all of which obey Langmuir−Hinshelwood mechanisms. The model attributes the catalysts for Type-1 and Type-2 to nanosized Ca-based particles and Ca species dispersed in an atomic scale, respectively. The initial concentration of Type-2 catalyst is saturated at a total Ca concentration over 1.0 wt %, while that of Type-1 increased in a linear manner with the total Ca concentration. The catalysis of Type-1 catalyst is more significant but diminished more quickly than that of the Type-2 one. Consequently, there was an optimum initial Ca concentration in the char around 2.0 wt % in terms of the time required for 99% char conversion. This trend is clearly different from that predicted from previous models that simply assumed loading saturation levels (LSLs). The kinetic model predicts characteristics of the steam gasification of the Ca-loaded char in an atmospheric bubbling fluidized bed at 800 °C. The characteristic time for the char gasification, which is given by the amount of in-bed char at steady state per feeding rate of the char (mc/Fc), is reduced by virtue of Ca by a factor of 7−8.. |
| 111. | Li-xin Zhang, Kudo Shinji, Naoto Tsubouchi, Hayashi Jun-ichiro, Yasuo Ohtsuka, Koyo Norinaga, Catalytic effects of Na and Ca from inexpensive materials on in-situ steam gasification of char from rapid pyrolysis of low rank coal in a drop-tube reactor, Fuel Processing Technology, 10.1016/j.fuproc.2013.03.009, 113, 1-7, 2013.09, Cost of catalysts is a crucial factor in realizing coal catalytic gasification process. In this study, inexpensive raw materials, soda ash (Na2CO3) and slaked lime (Ca(OH)2), were selected as catalyst precursors, and Na-, Ca- and Ca/Na-loaded coals were prepared by an ion-exchange procedure using a sub-bituminous coal (Adaro coal, Indonesia). These coal samples were rapidly pyrolyzed and in-situ gasified in an atmospheric drop-tube reactor (DTR) at 850–1000 °C under a steam partial pressure of 0.05 MPa. The Na and Ca catalysts showed remarkable activity for gasification, and the Ca/Na-loaded coal exhibited the highest reactivity among the coal samples prepared. The char yield of the Ca/Na-loaded coal at 1000 °C was as low as 17.6 mol-C per 100 mol-C of coal, and more than 70% (on carbon basis) of its primary char was gasified within 3 s. At 900 °C, the coal with Ca-loading of 3.2 wt.% showed catalytic activity higher than the coal with Ca-loading of 0.52 wt.%. At 950 and 1000 °C, however, the coal with the lower Ca-loading showed higher activity. The XRD analysis suggested that the Ca catalyst with the lower loading was more resistant to coarsening along with the progress of char gasification.. |
| 112. | Kudo Shinji, Zhenwei Zhou, Kento Yamasaki, Koyo Norinaga, Hayashi Jun-ichiro, Sulfonate Ionic Liquid as Stable and Active Catalyst for Levoglucosenone Production from Saccharides via Catalytic Pyrolysis, Catalysts, 3, 4, 757-773, 2013.09. |
| 113. | Ahu-Sheng Yang, Zhi-Min Zong, Bo Chen, Yun-Peng Zhao, Xing Fan, Xian-Yong Wei, Hayashi Jun-ichiro, Thermal Dissolution of Sgengli Lignite in Ethyl Acetate, International Journal of Oil, Gas and Coal Technology, 2013.08, Thermal dissolution (TD) of Shengli lignite (SL) in ethyl acetate (EA) was carried out under different conditions, including temperature, solvent to SL ratio (RS/SL), and time. The yields of EA-extractable fractions (EAEFs) increased with raising temperature from 240–300°C, but then decreased when the temperature was higher than 300°C, and the effects of RS/SL and time on EAEF yields was slight when RS/SL and time exceeded 20/1 and 1 h, respectively. These results suggest the optimal conditions for the TD of SL are 300°C, 20/1 of RS/SL, and 1 h. Then a couple of scale-up experiments were carried out under the optimal conditions with SL and dehydrated SL. According to analysis with a gas chromatography/mass spectrometry, major species in the EAEF from the TD of SL are oxygen-, sulfur-, and nitrogen-containing organic compounds along with elemental sulfur. The sulfur- and nitrogen-containing organic compounds detected include thioethers, thiophenes, amines, and nitrocyclic compounds. According to the structural characteristics of organic compounds in the EAEF, the mechanism for the TD of SL with EA was presumed.. |
| 114. | Idesh Saruul, Kudo Shinji, Hayashi Jun-ichiro, Catalytic Hydrothermal Reforming of Jatropha Oil in Subcritical Water for the Production of Green Fuels: Characteristics of Reactions over Pt and Ni Catalyst, Energy & Fuels, 27, 8, 4796-4803, 2013.07. |
| 115. | Hua Yang, Kudo Shinji, Hsiu-Po Kuo, Koyo Norinaga, Aska Mori, Ondrej Masek, Hayashi Jun-ichiro, Estimation of Enthalpy of Bio-oil Vapor and Heat Required for Pyrolysis of Biomass, Energy & Fuels, 10.1021/ef400199z, 27 , 5, 2675-2686, 2013.05, A method is proposed to estimate the enthalpy of bio-oil in the vapor phase, Hbo, as a function of temperature in the range 298.15–1000 K, of which experimental determination has not been done so far. The two equations proposed in this work allow estimation of the standard enthalpy of formation, Hbo,0, and the difference in the enthalpy between 298.15 K and a given temperature, ΔHbo(T), respectively, only based on the overall C, H, and O contents of crude bio-oil of that N and S contents are lower than 0.5 and 0.1 wt %-daf, respectively. These equations were optimized using thermodynamic data of 290 and 141 organic compounds for Hbo,0, and ΔHbo(T), respectively. Given the yields of bio-oil, char, and gas, elemental compositions of the bio-oil and char, and chemical composition of the gas, proposed equations predict the heat required for biomass pyrolysis, Qpy(Tpy), which is defined as the enthalpy difference between the products at the pyrolysis temperature, Tpy, and the biomass at 298.15 K. The predicted Qpy at Tpy = 773–823 K for five different types of dry biomass was in the range of 1.1–1.6 MJ kg–1.. |
| 116. | Hua Yang, Kudo Shinji, Seira Hazeyama, Koyo Norinaga, Ondrej Masek, Hayashi Jun-ichiro, Detailed Analysis of Residual Volatiles in Chars from the Pyrolysis of Biomass and Lignite, Energy & Fuels, 10.1021/ef4001192, 27, 5, 3209-3223, 2013.05, Pyrolysis of biomass or coal, if operated at temperatures high enough to complete tar evolution, is expected to give resulting char a tar-free nature. Use of such tar-free char instead of the original fuel in gasification would reduce or even completely eliminate the need for use of complex devices/mechanisms for tar/soot removal. Increasing pyrolysis temperature may not only decrease content of residual tar in the char, but also reduce its reactivity with gasifying agents. There is thus a range of optimum pyrolysis temperatures depending on the original fuel and type/mode of gasification, which yields char of suitable quality. In this work, a variety of char samples were prepared by pyrolysis (first pyrolysis) of three different woody biomass feedstock and a Victorian lignite with heating rate and peak temperature of 10 °C/min and 450–750 °C, respectively, and were further subjected to flash pyrolysis (second pyrolysis) at 920 °C. A gas-chromatography mass-spectrometry (GC/MS) detected more than 200 compounds in the volatile products from the second pyrolysis, and quantified 56 aromatic compounds over a range from benzene to coronene, which accounted for more than 85% of the compounds detected on a TIC peak area basis. Total emission of tar, defined as the aromatics except mono-aromatic hydrocarbons, from the biomass chars was 0.03–0.08 wt%-char even at the first pyrolysis temperature of 450 °C, and further decreased to a level around 0.01 wt% by raising the temperature to 600 °C. It was also found that despite containing as much as 20-27 wt.% of residual volatile matter, chars produced by pyrolysis at 500 °C contained less than 0.1 wt.% of residual tar.. |
| 117. | Yong Huang, Koyo Norinaga, Kudo Shinji, Hayashi Jun-ichiro, Keiji Tomura, Satoshi Horiuchi, Nobuo Takasu, Process Development toward Efficient Charcoal Production from Biomass Using Moving Bed, Journal of the Society of Powder Technology, Japan, 50, 3, 173-181, 2013.03. |
| 118. | Yasuhiro Sakurai, Shuji Yamamoto, Kudo Shinji, Koyo Norinaga, Hayashi Jun-ichiro, Conversion Characteristics of Aromatic Hydrocarbons in Simulated Gaseous Atmospheres in Reducing Section of Two-Stage Entrained-Flow Coal Gasifier in Air- and O2/CO2-blown Modes, Energy & Fuels, 10.1021/ef301658d, 27, 4, 1974-1981, 2013.03, Conversion of refractory aromatic hydrocarbons was studied with an atmospheric flow reactor that simulated the reducing section of a two-stage entrained-flow coal gasifier in air-blown and O2/CO2-blown (CO2 recycling) modes at temperatures of 1100–1400 °C. Mixed vapors of benzene and naphthalene (7/3 on a carbon basis) were fed into the reactor at total concentration in a range from 3.7 to 37 g·Nm–3 together with a CO–CO2–H2–H2O mixture in the O2/CO2-blown mode or CO–CO2–H2–H2O–N2 mixture in the air-blown mode. Soot was the major fate of the aromatics at the inlet benzene/naphthalene concentration of 35–37 g·Nm–3, and its yield was not influenced significantly either by the mode of gasification or temperature at 1200–1400 °C. The contribution of gas-phase reforming to the conversion of the aromatics became more important as their inlet concentration decreased. At the inlet concentration of 3.7–7.5 g·Nm–3, the O2/CO2-blown mode was clearly more effective in reducing the soot yield than the air-blown mode and increasing the gas yield. It was explained on the basis of a detailed chemical kinetic model that the increased partial pressure of CO2 induced a higher concentration of key active species such as hydroxyl radicals that initiated the oxidative decomposition of the aromatics.. |
| 119. | Yong Huang, Kudo Shinji, Ondrej Masek, Koyo Norinaga, Hayashi Jun-ichiro, Simultaneous Maximization of the Char Yield and Volatility of Oil from Biomass Pyrolysis, Energy & Fuels, 10.1021/ef301366x, 27, 1, 247-254, 2012.11. |
| 120. | Dieni Mansur, Takuya Yoshikawa, Koyo Norinaga, Hayashi Jun-ichiro, Teruyuki Tago, Takao Masuda, Production of ketones from pyroligneous acid of woody biomass pyrolysis over an iron-oxide catalyst, Fuel, 10.1016/j.fuel.2011.04.003, 103, 130-134, 2012.04. |
| 121. | Yong Huang, Shinji Kudo, Koyo Norinaga, Masaki Amaike, Jun-ichiro Hayashi, Selective Production of Light Oil by Biomass Pyrolysis with Feedstock-mediated Recycling of Heavy Oil, Energy & Fuels, 26, 1, 256–264, 2012.01. |
| 122. | Aska Mori, Sousuke Kubo, Shinji Kudo, Koyo Norinaga, Tetsuya Kanai, Hideyuki Aoki, Jun-ichiro Hayashi, Preparation of High-strength Coke by Carbonization of Hot-briquetted Victorian Brown Coal, Energy & Fuels, 26, 1, 296–301, 2012.01. |
| 123. | Saruul Idesh, Shinji Kudo, Koyo Norinaga, Jun-ichiro Hayashi, Catalytic Hydrothermal Reforming of Water-soluble Organics from the Pyrolysis of Biomass Using Ni/carbon Catalyst Impregnated with Pt, Energy & Fuels, 26, 1, 67–74, 2012.01. |
| 124. | Tsukasa Sueyasu, Tomoyuki Oike, Aska Mori, Shinji Kudo, Koyo Norinaga, Jun-ichiro Hayashi, Simultaneous Steam Reforming of Tar and Steam Gasification of Char from the Pyrolysis of Potassium-Loaded Woody Biomass, Energy & Fuels, 26, 1, 199–208, 2012.01. |
| 125. | Li-xin Zhang, Toru Matsuhara, Kudo Shinji, Hayashi Jun-ichiro, Koyo Norinaga, Rapid pyrolysis of brown coal in a drop-tube reactor with co-feeding of char as a promoter of in-situ tar reforming, Fuel, 10.1016/j.fuel.2011.12.030, 2011.12. |
| 126. | Koyo Norinaga, Yasuhiro Sakurai, Ryota Sato, Jun-ichiro Hayashi, Numerical Simulation of Thermal Conversion of Aromatic Hydrocarbons in the Presence of Hydrogen and Steam using a Detailed Chemical Kinetic Model, Chem. Eng. J., 178, 282–290, 2011.12. |
| 127. | Shinji Kudo, Zhenwei Zhou, Koyo Norinaga, and Jun-ichiro Hayashi, Efficient levoglucosenone production by catalytic pyrolysis of cellulose mixed with ionic liquid, Green Chem., 13, 3306-3311, 2011.10. |
| 128. | Sou Hosokai, Koyo Norinaga, Tokuji Kimura, Masaki Nakano, Chun-Zhu Li, Hayashi Jun-ichiro, Reforming of volatiles from the biomass pyrolysis over charcoal in a sequence of coke deposition and steam gasification of coke, Energy & Fuels, 25, 11, 5387-5393, 2011.10. |
| 129. | Koyo Norinaga, Tetsuya Shoji, Kudo Shinji, Hayashi Jun-ichiro, Detailed chemical kinetic modelling of vapour-phase cracking of multi-component molecular mixtures derived from the fast pyrolysis of cellulose, Fuel, 10.1016/j.fuel.2011.07.045, 103, 141-150, 2011.09. |
| 130. | Kudo Shinji, Keigo Sugiyama, Koyo Norinaga, Chun-Zhu Li, Tomohiro Akiyama, Hayashi Jun-ichiro, Coproduction of clean syngas and iron from woody biomass and natural goethite ore, Fuel, 10.1016/j.fuel.2011.06.074, 103, 64-72, 2011.08. |
| 131. | Shu Zhang, Jun-ichiro Hayashi, Chun-Zhu Li, Volatilisation and catalytic effects of alkali and alkaline earth metallic species during the pyrolysis and gasification of Victorian brown coal. Part IX. Effects of volatile-char interactions on char-H2O and char-O2 reactivities, Fuel, 90, 1655-1661, 2011.03. |
| 132. | Hayashi Jun-ichiro, Biomass Method, 2, 165-176, 2011.03. |
| 133. | Kongvui Yip, Esther Ng, Chun-Zhu Li, Jun-Ichiro Hayashi, Hongwei Wu, A mechanistic study on kinetic compensation effect during low-temperature oxidation of coal chars, Proceedings of the Combustion Institute, 33, 2, 1755-1762, 2011.01. |
| 134. | Nozomu Sonoyama, Kazunari Nobuta, Tokuji Kimura, Sou Hosokai, Jun-ichiro Hayashi, Teruoki Tago, Takao Masuda, Production of chemicals by cracking pyrolytic tar from Loy Yang coal over iron oxide catalysts in a steam atmosphere, Fuel Processing Technology, 92, 771-775, 2011.01. |
| 135. | Md. Saiful Alam, Agung Tri Wijayanta, Koichi Nakaso, Jun Fukai, Koyo Norinaga, Jun-ichiro Hayashi, A reduced mechanism for primary reactions of coal volatiles in a plug flow reactor , Combust. Theory and Modelling, 14, 6, 841-853, 2010.12. |
| 136. | Koyo Norinaga, Hiroshi Yatabe, Masahiro Matsuoka, Jun-ichiro Hayashi, Application of an existing detailed chemical kinetic model to a practical system of hot coke oven gas reforming by noncatalytic partial oxidation, Ind. Eng. Chem. Res. , 49, 10565–10571, 2010.06. |
| 137. | Toru Matsuhara, Sou Hosokai, Koyo Norinaga, Koichi Matsuoka, Chun-Zhu Li and Jun-ichiro Hayashi, In-Situ Reforming of Tar from the Rapid Pyrolysis of a Brown Coal over Char, Energy and Fuels, 24, 1, 76–83, 2010.05. |
| 138. | Makiko Kajita, Tokuji Kimura, Koyo Norinaga, Chun-Zhu Li, Hayashi Jun-ichiro, Catalytic and Noncatalytic Mechanisms in Steam Gasification of Char from the Pyrolysis of Biomass, Energy & Fuels, 24, 1, 108-116, 2010.05. |
| 139. | Sou Hosokai, Kazuya Kishimoto, Koyo Norinaga, Chu-Zhu Li, Jun-ichiro Hayashi, Characteristics of Gas-Phase Partial Oxidation of Nascent Tar from the Rapid Pyrolysis of Cedar Sawdust at 700-800 °C, Energy & Fuels, DOI:10.1021/ef100161q, 24, 2010.05. |
| 140. | Kongvui Yip, Fujun Tian, Jun-ichiro Hayashi, Hongwe Wu, Effect of Alkali and Alkaline Earth Metallic Species on Biochar Reactivity and Syngas Compositions during Steam Gasification, Energy and Fuels, 24, 1, 173–181, 2010.01. |
| 141. | Koyo Norinaga, Jun-ichiro Hayashi, Numerical Simulation of the Partial Oxidation of Hot Coke Oven Gas with a Detailed Chemical Kinetic Model, Energy and Fuels, 24, 1, 65–1723, 2010.01. |
| 142. | Tokuji Kimura, Masaki Nakano, Sou Hosokai, Koyo Norinaga, Chun-Zhu Li, Hayashi Jun-ichiro, Steam Reforming of Biomass Tar over Charcoal in a Coke-deposition/Steam-gasification Sequence, Proceedings of CHEMECA 2009, CD-ROM Edition, 2009.09. |
| 143. | Sou Hosokai, Kazuya Kishimoto, Koyo Noringa, Jun-ichiro Hayashi, Combined Effects of Temperature and Air Ratio on Vapor-Phase Cracking of Nascent Tar from the Rapid Pyrolysis of Cedar Sawdust, Proceedings of CHEMECA 2009, In press, 2009.09. |
| 144. | Yasuhiro Sakurai, Koyo Norinaga, Hayashi Jun-ichiro, Catalytic Partial Oxidation of Nascent Volatiles from Rapid Pyrolysis of Woody Biomass by Using Noble Metal Supported Alumina Foam, J. Jpn. Inst. Energy, 88, 10, 894-899, 2009.09. |
| 145. | Koyo Norinaga, Olaf Deutschmann, Naomichi Saegusa, Hayashi Jun-ichiro, Analysis of pyrolysis products from light hydrocarbons and kinetic modeling for growth of polycyclic aromatic hydrocarbons with detailed chemistry, J. Anal. Appl. Pyrolysis, 86, 1, 148-160, 2009.09. |
| 146. | Ondrej Masek, Sou Hosokai, Koyo Norinaga, Chun-Zhu Li, Hayashi Jun-ichiro, Rapid Gasification of Nascent Char in Steam Atmosphere during the Pyrolysis of Na- and Ca-Ion-Exchanged Brown Coals in a Drop-Tube Reactor, American Chemical Society, 23, 4496, 4501, 2009.07. |
| 147. | Yuichi Hata, Hadi Purwanto, Sou Hosokai, Hayashi Jun-ichiro, Yoshiaki Kashiwaya, Tomohiro Akiyama, Biotar Ironmaking Using Wooden Biomass and Nanoporous Iron Ore, Energy & Fuels, 23, 2, 1128-1131, 2009.03. |
| 148. | Koji Kuramoto, Koichi Matsuoka, Takahiro Murakami, Hideyuki Takagi, Tetsuya Nanba, Yoshizo Suzuki, Sou Hosokai, Hayashi Jun-ichiro, Cracking and Coking Behaviors of Nascent Volatiles Derived from Flash Pyrolysis of Woody Biomass over Mesoporous Fluidized-Bed Material, Industrial & Engineering Chemistry Research, 48, 6, 2851-2860, 2009.01. |
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