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研究者情報

マスター

アカウント（マスター）

  • 氏名

    望月　友貴(モチヅキ　ユウキ), モチヅキ　ユウキ

所属（マスター）

  • 工学研究院　附属エネルギー・マテリアル融合領域研究センター　エネルギー変換システム設計分野

所属（マスター）

  • 工学研究院　附属エネルギー・マテリアル融合領域研究センター　エネルギー変換システム設計分野

researchmap

プロフィール情報

学位

  • 博士(工学)（秋田大学）

プロフィール情報

  • 姓

    望月, モチヅキ

  • 名

    友貴, ユウキ

  • ID各種

    201301034517204857

業績リスト

研究キーワード

  • 環境化学   触媒変換化学   有機資源化学   

研究分野

  • ものづくり技術（機械・電気電子・化学工学） / 反応工学、プロセスシステム工学
  • ものづくり技術（機械・電気電子・化学工学） / 触媒プロセス、資源化学プロセス
  • 環境・農学 / 環境材料、リサイクル技術
  • 環境・農学 / 環境負荷低減技術、保全修復技術
  • エネルギー / 地球資源工学、エネルギー学

論文

  • Javzandolgor Bud, Yuuki Mochizuki, Naoto Tsubouchi
    Environmental Science and Pollution Research 28 46 66496 - 66500 2021年12月01日 
    The behavior of Hg release from iron ores during temperature-programmed heat treatment (TPHT) in air is studied, primarily using an online monitoring method. The Hg release behavior during TPHT depends significantly on the type of ore being processed, involving the evolved forms, Hg0 and Hg2+, and those that remain thermally stable up to 950 °C. Furthermore, TPHT experiments for model Hg compounds suggest the presence of several types of Hg forms (HgCl2, Hg2Cl2, HgS, HgO, HgSO4, and associated mineral Hg) in the considered iron ores. The findings of this study provide insights for designing an efficient method for the removal of Hg from iron ore and gaseous Hg.
  • Yuuki Mochizuki, Javzandolgor Bud, Jiaqian Liu, Miki Takahashi, Naoto Tsubouchi
    JOURNAL OF CLEANER PRODUCTION 305 2021年07月 [査読有り]
     
    The objective of this study was to elucidate in detail the Hg adsorption performance of Cl-loaded carbons obtained after chlorination of rice husk char (RC). Firstly, chlorine content/morphology/porosity of Cl-loaded carbons prepared were investigated. Subsequently, Hg adsorption performance of Cl-loaded carbon was tested. The effect of Cl on Hg adsorption was then investigated by comparing the adsorption performance of Cl-loaded carbons prepared from RC and demineralized RC (DRC). Cl content of RC and DRC reached a maximum value at 600 degrees C, and then decreased by 1000 degrees C. The pore properties of RC chlorinated residue increased with increasing chlorination temperature. The Hg adsorption performance of the RC chlorinated residues increased with increasing chlorination temperature. The maximum Hg adsorption capacity of RC chlorinated residue obtained at 1000 degrees C, 10min reached 620 mg/g; the capacity of chlorinated residue treated with DRC at 1000 degrees C, 10min was larger than that of DRC chlorinated at 600 IIC, which is largest Cl content. The adsorption kinetics and isotherm could be expressed by pseudo-first-order and Langmuir equations, respectively. The comparison of the porosity and Hg adsorption of DRC and RC chlorinated residue obtained at 1000 degrees C, 10min indicated that Cl-adsorbed on the carbon in RC during chlorination may also be involved in Hg adsorption. (C) 2021 Elsevier Ltd. All rights reserved.
  • Yuuki Mochizuki, Javzandolgor Bud, Jiaqian Liu, Miki Takahashi, Naoto Tsubouchi
    JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING 9 1 2021年02月 [査読有り]
     
    In this study, various iron hydroxides were prepared by different methods and their physical properties and P adsorption performance were investigated. The iron hydroxides prepared by five different methods (open-heating hydrolysis (Fe(H-A)), closed-heating hydrolysis (Fe(H-S)), urea (Fe(U)) addition, NaOH (Fe(S)) addition and NH3/NH4Cl buffer (Fe(A)) addition) were either akageneite or amorphous in nature. The specific surface area was larger for the amorphous precipitates, Fe(S) and Fe(A). Fe(A) showed the highest P adsorption performance among the adsorbents. Furthermore, there was a positive correlation between the specific surface area of the adsorbents and the maximum amount of adsorption. Fourier transform infrared spectroscopy (FT-IR) and N-2 adsorption analyses revealed that in iron hydroxides after P adsorption, the proportion of OH-OH hydrogen bonds and specific surface area decreased. Therefore, it was suggested that the specific surface area and OH species were important for analyzing the adsorption performance of the prepared iron hydroxide. On the other hand, the adsorption performance of Fe(A) decreased with increasing treatment temperature and pH. Fe(A) with 1 M NaOH solution after adsorption allowed almost complete desorption of the adsorbed P, which was confirmed by FT-IR, and the high specific surface area of the adsorbent was maintained. Therefore, it was concluded that Fe (A) can be a recyclable, high P uptaking adsorbent.
  • Yuuki Mochizuki, Miki Takahashi, Javzandolgor Bud, Yuting Wang, Naoto Tsubouchi
    ISIJ INTERNATIONAL 61 8 2200 - 2210 2021年 [査読有り]
     
    In this study, a calcium/carbon composite (Ca/C) was prepared from porous Ca0 by the water vapor swelling method; its pores were filled with tar-derived carbonaceous material to produce high-strength and highly reactive coke. The properties of coke prepared by blending the Ca/C composite and caking-coal were then investigated. The mesopores in the swelling Ca disappeared and the crushing strength was developed by filling tar-derived carbonaceous material into the porous Ca. Thus, a Ca/C composite could be produced by the abovementioned method, wherein the tar-derived carbonaceous material and Ca species were in close proximity. When the Ca/C composite was blended into the caking-coal, the strength of the coke obtained increased by up to 50% of Ca/C blending, which made it possible to produce high-strength coke. On examining the C structure of the prepared coke by X-ray diffraction, that of the original coke was found to be almost unchanged by adding the Ca/C composite. Conversely, the Ca/C blended-coke showed higher CO2 gasification reactivity than the original coke prepared from caking-coal. Based on the CO2 gasification reactivity test of the demineralized coke, it was clear that an increase in the gasification reactivity of the Ca/C blended-coke depended upon the catalytic effect of Ca. Thus, this method helped produce high-strength and highly reactive coke.
  • Naoto Tsubouchi, Ryo Naganuma, Yuuki Mochizuki, Hideyuki Hayashizaki, Takahiro Shishido, Atul Sharma
    TETSU TO HAGANE-JOURNAL OF THE IRON AND STEEL INSTITUTE OF JAPAN 107 1 15 - 23 2021年01月 [査読有り]
     
    In order to produce high-strength coke from low-quality coals, noncovalent bonds between O-functional groups in coal were cleaved by pyridine containing HPC pyridine soluble and HPC-derived thermoplastic components were introduced into the pores formed by swelling; thus, the synergistic effect during carbonization of the suppression of cross-linking reactions and the fluidity amplification due to close placement of coal and thermoplastic components was investigated. When HPC was extracted with pyridine, a decrease in O-functional groups was observed in the pyridine-soluble and pyridine-insoluble components. When HPC was extracted with MeOH, on the other hand, O-functional groups in HPC selectively moved into the soluble components. When non- or slightly-caking coal was chemically-modified with the prepared HPC pyridine-soluble components by utilizing the solvent-swelling effect of pyridine, the fluidity improved compared with the coals physically mixed with the soluble components or HPC. On the other hand, the fluidity of the chemically-modified sample with the MeOH-soluble components hardly changed from that of the original sample, and no effect of the modification with the thermoplastic component was observed. Furthermore, it was clarified that higher-strength coke can be produced from the chemically-modified sample with the HPC pyridine -soluble components than from the original coal or the physically mixed coal with the soluble components. The contraction behavior during carbonization of the chemically-modified sample with the soluble components and that of the original coal was investigated; as a result, a large difference was not observed between these two. Thus, it was found that high-strength coke can be produced from low-quality coals by the present method.
  • Naoto Tsubouchi, Ryo Naganuma, Yuuki Mochizuki, Hideyuki Hayashizaki, Takahiro Shishido
    TETSU TO HAGANE-JOURNAL OF THE IRON AND STEEL INSTITUTE OF JAPAN 107 1 35 - 43 2021年01月 [査読有り]
     
    In the present study, we prepare several types of specimens from non-caking coal including specimens in which noncovalent bonds between O-functional groups in coal are cleaved by pyridine and HPC-derived thermoplastic components are introduced into the pores produced by swelling, as well as specimens consisting of physical blends with HPC and examine the influence of heating conditions and types of caking agents on the production of high-strength coke using a SUS tube. We also investigate the influence of heating conditions and types of caking agents on the strength of coke from pelleted specimens and determine the optimal conditions for producing high-strength coke from non-caking coal. HPC with a wide range of thermoplastic properties is more effective as caking agents than additives containing only low-molecular-weight or high-molecular-weight components. In addition, the strength of the produced coke depends on the amount of the additive, and optimal values of the additive amount are present. It was found that the following heating schedule is effective for producing high-strength coke KP from non-caking coal with added caking agents: First, high-speed heating (20 degrees C/min) to an intermediate temperature in the range 400-600 degrees C, recognized as the thermoplastic temperature range for typical caking coal; then, low-speed heating (3 degrees C/min) to the temperature range of 900-1000 degrees C. Moreover, we demonstrate that, by increasing the rate of heating in the thermoplastic temperature range, it is possible to reduce the amount of caking agent added.
  • Naoto Tsubouchi, Ryo Naganuma, Yuuki Mochizuki, Hideyuki Hayashizaki, Takahiro Shishido
    TETSU TO HAGANE-JOURNAL OF THE IRON AND STEEL INSTITUTE OF JAPAN 107 1 24 - 34 2021年01月 [査読有り]
     
    In this work, we studies the production of higher-strength coke from chemically-loaded coal in which noncovalent-bonds between O-functional groups in coal are cleaved by pyridine and HPC-derived thermoplastic components are introduced into the pores produced by swelling. The effect of heating rate up to thermoplasticity temperatures of coal on coke strength is first investigated. To examine synergistic effects due to further fluidity enhancements caused by the increased proximity of coal to thermoplastic components during carbonization, the influence of heating rate on coke-strength prepared from pelleted-coal also examined, as described above, to clarify the optimal heating conditions for yielding high-strength coke from slightly-caking coal. An investigation of the use of a SUS-tube to produce high-strength coke from slightly-caking coal with chemically-loaded HPC pyridine-soluble components reveals that high-strength coke may be obtained by 20 degrees C/min to 400 degrees C and then continuing to heat at 3 degrees C/min to 1000 degrees C. On the other hand, when producing coke from formed specimens consisting of slightly-caking coal with chemically-loaded HPC pyridine-soluble components, we exhibit that, by heating first at 20 degrees C/min to 500-600 degrees C and then heating at 3 degrees C/ min to 900 degrees C, it is possible to produce coke whose strength rivals that of coke produced by carbonization at 3 degrees C/min of strongly-caking coal. In addition, in producing high-strength coke from formed slightly-caking coal, an optimal amount of additive is present for all types of additive considered HPC physical blend, chemically-loaded pyridine-soluble HPC and physical blend of pyridine-insoluble HPC components and, with chemically-loaded pyridine-soluble HPC, it is possible to prepare particularly high-strength coke.
  • Yuuki Mochizuki, Javzandolgor Bud, Jiaqian Liu, Naoto Tsubouchi
    ACS OMEGA 5 45 29110 - 29120 2020年11月 [査読有り]
     
    The production of silicone tetrachloride (SiCl4) from rice husk char by chlorination was investigated, and the effect of the char preparation temperature on SiCl4 volatilization and the coexisting element species in the char was examined. The behavior of chlorine (Cl) and the change in pore properties during char chlorination were analyzed, and the reaction mechanism was discussed. The performance of Hg ion removal of the chlorination residue was also investigated. At 1000 degrees C chlorination, the optimum rice husk pyrolysis temperature for attaining high ashrelease extent was 800 degrees C. Ash volatilization during char chlorination with heat treatment mainly occurred at >300 degrees C and reached a release extent of similar to 75% by 1000 degrees C. Si and P volatilization started at >300 degrees C and reached 70-75% by 1000 degrees C. In contrast, Na and K the volatilization occurred at >700 degrees C, with a 50% volatilization extent by 1000 degrees C. Mg and Ca had a volatilization rate of <20% by 1000 degrees C. When the char was held at 1000 degrees C, the release extent of Si and P reached 75-80% by 10 min. Na and K volatilized almost completely by 10 min, and the release extent of Mg and Ca increased with increasing holding time and became 10-50% by 60 min. The Cl content in the residue obtained at each chlorination temperature increased from 300 to 700 degrees C and then decreased with increasing temperature. The majority of CI taken up in the residue was an H2O insoluble form. The surface area and pore volume of the chlorinated residue tended to increase with increasing chlorination temperature, with the former increasing to 335 m(2)/g at 1000 degrees C and 10 min holding. The maximum mercury adsorption amount of the chlorinated residue obtained at 1000 degrees C, 10 min holding was 620 mg/g, indicating the mercury ion adsorption performance of the chlorinated residue.
  • Yuuki Mochizuki, Naoto Tsubouchi, Katsuyasu Sugawara
    RESOURCES CONSERVATION AND RECYCLING 158 2020年07月 [査読有り]
     
    Herein, we investigated the volatilization behavior of slag elements during chlorination of converter slag and Kambara reactor slag to develop a method for recycling steelmaking slag. Then, the effects of holding time and carbon addition (carbon reduction) (denoted as a combination of carbon reduction/chlorination) on volatilization were examined in detail. Most of the Fe in the slag was volatilized by chlorination up to 1000 degrees C, independently from the type of slag. Moreover, it was possible to volatilize most of the Ti and approximately 40% of the Mg by chlorination at 1000 degrees C for 60 min. That is, Fe and Ti were completely separated from the slag by chlorination. Fe was volatilized below 1000 degrees C during carbon reduction/chlorination, and remarkable volatilization (40-90%) of Ti and P was also observed until 1000 degrees C. Therefore, the separation of each element using the volatilization kinetics of Fe, Ti, and P was difficult during the carbon reduction/chlorination. In contrast, when carbon was added to the chlorination residue obtained at 1000 degrees C for 60 min and then subjected to a carbon reduction/chlorination treatment, most of the Mg, Si, Al, and Ca remained in the solid phase up to 1000 degrees C, and P was the only element volatilized. The volatilization temperature (> 1000 degrees C) and the proportion of P were lower than those of the conventional carbon reduction method of slag. Therefore, it was found that the combination of chlorination and carbon reduction/chlorination methods is effective for the separation of Fe, Ti, and P from slag.
  • Kosuke Sakusabe, Yuuki Mochizuki, Takahiro Kato, Hirokazu Okawa, Katsuyasu Sugawara
    JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 53 7 351 - 358 2020年07月 [査読有り]
     
    A process for selectively recovering titanium, vanadium, and tungsten from spent denitrification catalysts generated in coal-fired power plants was developed in this study. Carbon was added as a reducing agent and the chloride volatilization behavior of rare metals under a chlorine gas flow was subsequently tracked. This demonstrated that the chloride volatilization reaction is promoted by the addition of carbon. In addition, if the spent catalyst is heat-treated in methanol vapor to deposit solid carbon on the catalyst surface, the chloride volatilization promotion is particularly high. After carbon was added by this method, heating to 400 degrees C under a chlorine gas flow selectively released rare metals without releasing coexisting elements such as iron and aluminum. In addition, the released rare metals were converted into chlorides upon cooling and were completely recovered in solid or liquid form.
  • Yuuki Mochizuki, Jun Ma, Yukihiro Kubota, Kazuya Uebo, Naoto Tsubouchi
    FUEL PROCESSING TECHNOLOGY 203 2020年06月 [査読有り]
     
    Carbon/carbon composites were prepared from pyrolyzed-chars of lignite or low-strength coke (drum index of DI6150 = 52) and a coke-oven-gas tar through a gaseous-tar vapor deposition method to investigate the possibility of producing high-strength coke from low-grade coal or coke. The optimum vapor deposition temperature was examined under tar pyrolysis temperature of 700 degrees C and holding time of 30 min. The highest strength of prepared composite was observed at a vapor deposition temperature of 300 degrees C. The pore volume of the composite prepared at the vapor deposition temperature of 300 degrees C was the smallest among other samples prepared at that of 400-700 degrees C. The strength was improved by filling the carbonaceous materials derived from tar into the pores. The tar utilization coefficient was extremely low at 1.0 wt% or less. When same treatment was carried out for coke with different DI and pyrolyzed-cahr of lignite under the optimum conditions, it became clear that the composite prepared from any coke or pyrolyzed-char of lignite is comparable in strength to high-strength coke (DI6150 = 87). It was thus found that the present method can prepare high-strength coke from low-grade carbonaceous materials. The gasification rate of the composite prepared from low-strength coke was 0.5 times smaller than that of the original sample.
  • Naoto Tsubouchi, Natsumi Matsuoka, Ken Fukuyama, Yuuki Mochizuki
    CHEMICAL ENGINEERING RESEARCH & DESIGN 156 138 - 145 2020年04月 [査読有り]
     
    In this study, the HCl absorption performance of cheap natural soda ash loaded on a honeycomb support as a hot gas cleanup method was investigated by using flow-type fixed-bed reactor. The honeycomb-supported soda ash improved the HCl absorption extent significantly at the 1-ppm breakthrough time compared to the result without the support; thus, the use of the support was justified. The HCl removal performance of the honeycomb-supported soda ash depended significantly on temperature (300-600 degrees C). Under the present conditions, the absorption extent at 1-ppm breakthrough time was maximized at 500 degrees C. This absorption extent increased as the HCl concentration in the supplied gas decreased, and it was assumed that this absorbent was suited to actual coal gasification processes. No change in the HCl absorption extent (60-65 %) was observed for Na2CO3 loading between 33 and 65 mass%. The natural soda ash (Na2CO3) loaded on a honeycomb support changed to NaCl after HCl absorption examination. Regenerated HCl absorbent from spent honeycomb showed similar HCl absorption performance with fresh absorbent at 300-500 degrees C. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
  • Yuuki Mochizuki, Naoto Tsubouchi
    HYDROMETALLURGY 190 2019年12月 [査読有り]
     
    In the present the study, the hydrothermal removal of gangue components (Si, Al, and P) from iron ore as a means of producing high-grade iron ore from low-grade iron ore (limonite) is investigated. Ores of different types and countries of origin are treated with several kinds of solvents, and the effects of temperature and type of solvent on the extent of gangue removal are rationalized in terms of the chemical and physical compositions of the iron ores used. Relatively good correlation is observed between the Al and P contents of the iron ore specimens used in this study, while the gangue content correlates with the iron content. When the iron ores are treated with distilled water at 16.5 MPa and temperatures up to 350 degrees C, the removal rate is low, irrespective of the type of iron ore. Furthermore, gangue removal by hydrothermal treatment with 1 M NaOH is higher than those when 1 M NaHCO3 and 1 M Na2CO3 solutions are used. The effects of NaOH concentration and temperature on gangue removal by hydrothermal treatment are investigated using 5 M NaOH, and removal rates of 10-91% for Si, 39-70-% for Al, and 38-76% for P are achieved by treatment at 300 degrees C for most of the specimens. In addition, there is good correlation between the removal rates of Al and P by hydrothermal treatment with 5 M NaOH. Although the development of pores by calcination of iron ore positively affects gangue removal at room temperature by NaOH leaching, no such effect is observed for hydrothermal treatment with NaOH up to 350 degrees C. The specific surface areas and pore volumes of the in iron ore specimens decrease after hydrothermal treatment with NaOH. In addition, the alpha-FeOOH observed in the iron ores before hydrothermal treatment with NaOH is transformed to Fe2O3 in the treated samples. These results demonstrate that this method is effective for converting low-grade iron ores into high-grade iron ores with low porosity, low gangue content, and high Fe content (Fe2O3).
  • Yuuki Mochizuki, Naoto Tsubouchi
    ACS OMEGA 4 22 19723 - 19734 2019年11月 [査読有り]
     
    In this study, a combination of alkali roasting and hydrothermal treatment is used as a method of gangue (Si, Al, and P) removal from iron ores as a means to upgrade low-grade iron ore (limonite) into a high-grade iron ore with low gangue content, low porosity, and high Fe and Fe2O3 content to enhance the sustainable development of iron and steel industries. The effects of the combined treatments (NaOH hydrothermal treatment and H2O/NaOH hydrothermal treatment of the alkali roasted sample), the iron ore type, their physical properties, and their calcination/roasting temperatures on the removal extent of gangue are investigated. The extent of Si, Al, and P removal by subjecting iron ores to a 5 M NaOH hydrothermal treatment at 300 degrees C reached 10-91%, 39-70%, and 38-76%, respectively. When the iron ores are roasted with NaOH at 350 degrees C, alpha-FeOOH in limonite transfers to NaFeO2. On the other hand, for alkali roasted iron ores that inherently contain Fe2O3, Fe2O3 and Na2CO3 are also observed after the roasting treatment. Higher Al and P removal extents are observed for H2O leaching at room temperature in the prepared roasted samples (Roasting/H2O_RT) as compared to NaOH hydrothermal treatment, whereas that of Si is low for all samples, except the iron ore with the highest Fe content. After the H2O leaching process, the Fe form is found to be in the amorphous form for all samples, except for the iron ore sample of the highest Fe content. The reason for this is thought to be due to the large amount of unreacted Fe2O3 with NaOH during the roasting process. The specific surface area significantly increases after the Roasting/ H2O_RT treatment in all samples due to the dehydration of goethite (alpha-FeOOH Fe2O3 + H2O) during the roasting treatment and gangue removal during H2O leaching. When the roasted samples are supplied for hydrothermal treatment by H2O at 300 degrees C (Roasting/H2O_SC), the removal rate of Si and P increases as compared with the Roasting/H2O_RT treatment. The influence of temperatures of calcination and the roasting treatment on the extent of gangue removal in 5 M NaOH hydrothermal, Roasting/H2O_RT, and Roasting/H2O_SC treatments is small. When NaOH hydrothermal treatment is carried out on the samples that have undergone the Roasting/H2O_RT treatment, a gangue removal extent of above 70-97% was achieved, except for the iron ore with the lowest P content, which had the largest loss of ignition and the lowest Fe content. In addition, it is revealed that low-grade iron ore with a high pore properties, alpha-FeOOH content, and gangue content can be upgraded to a high-grade iron ore with a low pore property (low specific surface area and pore volume), high Fe2O3 content, and low gangue content using the above method. Therefore, this method is promising as a method for upgrading low-grade iron ore.
  • Yuuki Mochizuki, Naoto Tsubouchi
    FUEL PROCESSING TECHNOLOGY 193 328 - 337 2019年10月 [査読有り]
     
    To further the utilization of biomass for cokemaking at ironmaking facilities and to reduce CO2 emissions, carbon/carbon composite (CC) from tar and char is produced from the pyrolysis of a woody biomass with quartz-made fixed-bed reactor at 10 C/min to 200-500 C. Then, the optimum conditions for preparing high strength coke by blending caking coal and CC is investigated. The specific surface areas of char and tar yields via sawdust pyrolysis are maximized at 550 C. When the mixture of pyrolyzed char and tar produced in large quantities during the same process is co-pyrolyzed, the pore observed in prepared char completely disappears due to filling of carbonaceous materials derived from tar-pyrolysis into char pores, and char yield is improved. When the strength of the coke prepared from the mixture and pelletization of caking coal and prepared CC is investigated, the indirect tensile strength of the prepared coke tends to decrease with an increase in temperature of CC preparation. And, it was found that the optimum CC preparation temperature is 250 C (CC250) for high-strength coke preparation. Although increasing the blending ratio of CC250 to caking-coal decreases the strength of the coke, the extent of decreasing strength is smaller than that of slightly-caking coal or pyrolyzed char blended to caking coal. The filling of carbonaceous materials derived from tar-pyrolysis into pores of sawdust char during CC preparation influences the coke strength, such that the value is greater than that of physical mixture of sawdust char and carbonaceous materials from tar prepared with individually (carbonaceous materials derived from tar not loaded into pore in char).
  • Yuuki Mochizuki, Naoto Tsubouchi
    METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE 50 5 2259 - 2272 2019年10月 [査読有り]
     
    The optimal conditions for preparing composites, in which tar-derived carbonaceous materials completely fill the pores in Indonesian limonite(IL), were investigated using the vapor deposition (VD) method of tar. Characterization of the composites and their reactivity (reduction/combustion/gasification) during heat treatment was examined. The specific surface area and pore volume of the as-received-IL and dehydrated-IL decreased after the VD treatment for different combinations of tar pyrolysis temperature (TPT) and VD temperature (VDT). It was also noted that the carbon content and crushing strength of the samples increased after the VD treatment, and the optimal values for the TPT-VDT are 700 degrees C and 350 degrees C. The C content and the crushing strengths of the composites prepared at TPT-VDT = 700 degrees C to 350 degrees C increased with an increase of the VD time to 50 pct carbon content and 10 daN at 240 minutes, respectively. The strength was similar to that of commercial metallurgical coke used in blast furnaces. The reduction of the composite prepared at TPT-VDT = 700 degrees C to 350 degrees C for 240 minutes started above 400 degrees C and was almost completed at 1000 degrees C. This reduction rate was higher than that of commercial cold-bonded pellets or a coke/IL mixture. The combustion and gasification rates of the composites prepared under different conditions depended on the preparation condition of composites, and the rates were higher than those of commercial metallurgical coke used in blast furnaces.
  • Yuuki Mochizuki, Yukihiro Kubota, Kazuya Uebo, Naoto Tsubouchi
    POWDER TECHNOLOGY 355 782 - 792 2019年10月 [査読有り]
     
    Carbon/carbon composites were prepared by pyrolysis of mixtures of coke oven gas tar and low-grade cokes or pyrolyzed chars from lignite and sub-bituminous coals. The indirect tensile strength of each composite prepared reached approximately 7.5 MPa, which is comparable to those of high-grade cokes used in commercial blast furnaces. Although the CO2 gasification rates of the composites prepared from low-grade cokes decreased compared to those of the original samples, those of the composites prepared from pyrolyzed chars were almost the same. From the results of mercury intrusion porosimetry analysis and O-2 adsorption temperature-programmed-desorption tests of samples before and after compositing, it was suggested that the decrease in gasification rates of composites prepared from cokes occurred owing to a decrease in the pores and number of active sites on the original cokes. (C) 2019 Elsevier B.V. All rights reserved.
  • Naoto Tsubouchi, Javzandolgor Bud, Yuuki Mochizuki
    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 258 2019年08月 [査読有り]
  • Takahiro Kato, Kosuke Sakusabe, Yuuki Mochizuki, Hirokazu Okawa, Katsuyasu Sugawara
    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 258 2019年08月 [査読有り]
  • Naoto Tsubouchi, Yuuki Mochizuki, Yuji Shinohara, Akiyuki Kawashima, Yasuo Ohtsuka
    FUEL 246 51 - 59 2019年06月 [査読有り]
     
    A model carbon prepared from phenolic resin was O-2-activated and then impregnated with Ca, Cu or Zn to clarify chlorine behavior in coal utilization. Ease of interaction between HCl and the carbon material was enhanced at 100-300 degrees C. The concentration at which HCl reacted with Ca, Cu and Zn was high. The surface chloric species that were generated by reaction of the carbon substrate with HCl were studied using X-ray photoelectron spectroscopy (XPS) and temperature programmed desorption (TPD). XPS measurements suggested the presence of inorganic chloride and organic chlorine species after reaction with HCl. When the carbon samples were washed after the HCl reaction, most of the HCl was eluted. Chemically adsorbed HCl species were also detected by TPD measurement; the presence of inorganic chloride, organic chlorine and chemically adsorbed HCl species were indicated. No correlation was determined between the amount of organic chlorine species generated and the number of activated carbon sites at 100 degrees C. However, the amount of organic chlorine at 300 degrees C indicated a tendency to increase with the number of carbon sites, and the surface functional oxygen groups acted as sites for the generation of C-Cl bonds. As a result, possible scheme for the generation of organic chlorine species at low temperature by reaction between HCl and the metal-doped (Ca, Cu or Zn) carbon is discussed.
  • Naoto Tsubouchi, Javzandolgor Bud, Yuuki Mochizuki
    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 257 2019年03月 [査読有り]
  • Yuuki Mochizuki, Yohei Ono, Naoto Tsubouchi
    FUEL 237 735 - 744 2019年02月 [査読有り]
     
    The evolution of inorganic-gases (H-2, CO, CO2 or H2O) and hydrocarbon gases CH4, C-2(C2H4, C2H6), or C-3(C3H6 + C3H8) during the carbonization of caking coals is examined to clear the influence of the evolution amount of these gases on the Gieseler maximum fluidity (MF) and coke strength (DI15150). The samples are carbonized at 3 degrees C/min up to 1000 degrees C in high-purity He. The MF and the evolution profile of gases depend on the coal type. A negative relation exists between evolution amounts of gases, except for H-2, until initial softening temperature (IST) and MF values. Additionally, the evolution amounts of inorganic gases, except for H-2, until the IST increase with the increase of the carboxyl (COOH) group contents in raw coal. Moreover, the MF values trends to decrease with the increase in the COOH in raw samples. Thereby, it is found that the inherently-present coal-O adverse affect coal fluidity. Drum index (DI15150) of coke increases with the increase of C%-dry ash free (daf), fixed carbon (FC) %-dry, and reflectance (R-0) vol% in raw coal, while the values decrease with the increase O%-daf and volatile matter (VM) %-dry. The DI15150 values exhibit an increasing trend with regard to the amount of the evolved H-2 or CH4 during the carbonization. However, the values decrease as the amount of O-containing gases increased. A similar trend is observed in semi-coke and coke, where the values decrease as the remaining O% increased. Although the proportion of turbostatic-C (T-carbon) in coke depends on the coal type, DI15150 increases as the proportion of T-carbon increased. Therefore, it is found that the coal-O also has an adverse influence on coke strength.
  • Takahiro Kato, Kosuke Sakusabe, Yuki Mochizuki, Hirokazu Okawa, Katsuyasu Sugawara
    Reaction Chemistry & Engineering 4 7 1208 - 1215 2019年 [査読有り]
     

    Reduction–volatilization of arsenic from a denitration catalyst obtained from a coal-fired power plant using a gaseous reducing agent was investigated to develop a dry arsenic removal process.

  • Naoto Tsubouchi, Ryo Naganuma, Yuuki Mochizuki, Hideyuki Hayashizaki, Takahiro Shishido
    ISIJ INTERNATIONAL 59 8 1427 - 1436 2019年 [査読有り]
     
    In this work, we studies the production of higher-strength coke from chemically-loaded coal in which noncovalent-bonds between O-functional groups in coal are cleaved by pyridine and HPC-derived thermoplastic components are introduced into the pores produced by swelling. The effect of heating rate up to thermoplasticity temperatures of coal on coke strength is first investigated. To examine synergistic effects due to further fluidity enhancements caused by the increased proximity of coal to thermoplastic components during carbonization, the influence of heating rate on coke-strength prepared from pelleted-coal also examined, as described above, to clarify the optimal heating conditions for yielding high-strength coke from slightly-caking coal. An investigation of the use of a SUS-tube to produce high-strength coke from slightly-caking coal with chemically-loaded HPC pyridine-soluble components reveals that high-strength coke may be obtained by 20 degrees C/min to 400 degrees C and then continuing to heat at 3 degrees C/min to 1 000 degrees C. On the other hand, when producing coke from formed specimens consisting of slightly-caking coal with chemically-loaded HPC pyridine- soluble components, we exhibit that, by heating first at 20 degrees C/min to 500-600 degrees C and then heating at 3 degrees C/min to 900 degrees C, it is possible to produce coke whose strength rivals that of coke produced by carbonization at 3 degrees C/min of strongly-caking coal. In addition, in producing high-strength coke from formed slightly-caking coal, an optimal amount of additive is present for all types of additive considered - HPC physical blend, chemically-loaded pyridine-soluble HPC and physical blend of pyridine-insoluble HPC components - and, with chemically-loaded pyridine-soluble HPC, it is possible to prepare particularly high-strength coke.
  • Naoto Tsubouchi, Ryo Naganuma, Yuuki Mochizuki, Hideyuki Hayashizaki, Takahiro Shishido
    ISIJ INTERNATIONAL 59 8 1419 - 1426 2019年 [査読有り]
     
    In the present study, we prepare several types of specimens from non-caking coal - including specimens in which noncovalent bonds between O-functional groups in coal are cleaved by pyridine and HPC-derived thermoplastic components are introduced into the pores produced by swelling, as well as specimens consisting of physical blends with HPC - and examine the influence of heating conditions and types of caking agents on the production of high-strength coke using a SUS tube. We also investigate the influence of heating conditions and types of caking agents on the strength of coke from pelleted specimens and determine the optimal conditions for producing high-strength coke from non-caking coal. HPC with a wide range of thermoplastic properties is more effective as caking agents than additives containing only low- molecular-weight or high-molecular-weight components. In addition, the strength of the produced coke depends on the amount of the additive, and optimal values of the additive amount are present. It was found that the following heating schedule is effective for producing high-strength coke from non caking coal with added caking agents: First, high-speed heating (20 degrees C/min) to an intermediate temperature in the range 400-600 degrees C, recognized as the thermoplastic temperature range for typical caking coal; then, low-speed heating (3 degrees C/min) to the temperature range of 900-1 000 degrees C. Moreover, we demonstrate that, by increasing the rate of heating in the thermoplastic temperature range, it is possible to reduce the amount of caking agent added.
  • Naoto Tsubouchi, Ryo Naganuma, Yuuki Mochizuki, Hideyuki Hayashizaki, Takahiro Shishido, Atul Sharma
    ISIJ INTERNATIONAL 59 8 1396 - 1403 2019年 [査読有り]
     
    In order to produce high-strength coke from low-quality coals, noncovalent bonds between O-functional groups in coal were cleaved by pyridine containing HPC pyridine soluble and HPC-derived thermoplastic components were introduced into the pores formed by swelling; thus, the synergistic effect during carbonization of the suppression of cross-linking reactions and the fluidity amplification due to close placement of coal and thermoplastic components was investigated. When HPC was extracted with pyridine, a decrease in O-functional groups was observed in the pyridine-soluble and pyridine-insoluble components. When HPC was extracted with MeOH, on the other hand, O-functional groups in HPC selectively moved into the soluble components. When non- or slightly-caking coal was chemically-modified with the prepared HPC pyridine-soluble components by utilizing the solvent-swelling effect of pyridine, the fluidity improved compared with the coals physically mixed with the soluble components or HPC. On the other hand, the fluidity of the chemically-modified sample with the MeOH-soluble components hardly changed from that of the original sample, and no effect of the modification with the thermoplastic component was observed. Furthermore, it was clarified that higher-strength coke can be produced from the chemically-modified sample with the HPC pyridine-soluble components than from the original coal or the physically mixed coal with the soluble components. The contraction behavior during carbonization of the chemically-modified sample with the soluble components and that of the original coal was investigated; as a result, a large difference was not observed between these two. Thus, it was found that high-strength coke can be produced from low-quality coals by the present method.
  • Yuuki Mochizuki, Junpei Watanabe, Naoto Tsubouchi
    ENERGY & FUELS 32 12 12328 - 12336 2018年12月 [査読有り]
     
    The removal of dibenzothiophene (DBT) in a hydrocarbon liquid model fuel (MF) by Ni-loaded carbon (Ni/C) prepared from lignite has been studied with a flow-type fixed-bed reactor. The performance of Ni/C in the removal of 500 ppmw S in MF depends on the amount of Ni loaded. The highest ability is observed at 11 wt % dry Ni under the conditions of a reduction time of 0.5 h and a desulfurization temperature of 200 degrees C. In addition, the reduction time influences the breakthrough curves, and it is found that the optimum condition for DBT removal from MF by Ni/C is 1.0 h. When the desulfurization temperature for evaluating the DBT removal ability of Ni/C is increased, the breakthrough and saturation points also increase, and the greatest performance is observed at 200 degrees C. From the identification of MF treated by Ni/C, it was found that a part of DBT in the MF feed is removed by chemical adsorption via cleavage of the C-S bond in the DBT molecule to form biphenyl which can adsorb onto a carbonaceous material surface.
  • Naoto Tsubouchi, Yuuki Mochizuki, Yuji Shinohara, Yuu Hanaoka, Yasuo Ohtsuka, Koji Kuramoto, Koichi Matsuoka
    FUEL 234 406 - 413 2018年12月 [査読有り]
     
    Calcium ion exchange was performed in Indonesian low-rank coal using saturated aqueous solutions of Ca(OH)(2) at 30.0 +/- 0.1 degrees C without pH adjustment. The Ca2+ concentration and pH were monitored during ion exchange. A coal product was obtained with 3.2 mass% Ca2+. Gasification of the ion-exchanged samples was conducted in a circulating dual bubbling fluidized bed (CDBFB) reactor at 700 degrees C, 800 degrees C, and 900 degrees C. Coal carbon conversion into carbonaceous gases (CO, CO2, CH4, and C-2 hydrocarbons) using the Ca2+-exchanged coal achieved 78% at 900 degrees C in the CDBFB. The Ca catalyst led to the greatest rate enhancement at 800 degrees C, resulting in a twofold increase in the gas product yield compared to that without Ca.A comparison of carbon conversion between the CDBFB and fixed-bed reactors revealed that the conversion value using the CDBFB at 700 degrees C was very small. Regarding an examination of this influence in detail, it seems that the existing H-2 adhered primarily to the active sites of the char, and the use of Ca2+-exchanged coal led to a reverse shift reaction.
  • Yuuki Mochizuki, Yukihiro Kubota, Kazuya Uebo, Naoto Tsubouchi
    FUEL 232 780 - 790 2018年11月 [査読有り]
     
    In this fundamental laboratory scale investigation, carbon/carbon (C/C) composites were prepared from a mixture of pyrolyzed-chars of low-rank coals (lignite and sub-bituminous coals) or low-strength cokes (drum index: DI6150 = 52 and 73) and coke-oven gas (COG) tar to investigate the possibility of producing high-strength coke for blast furnace use from low-grade coals or cokes. In addition, the optimum conditions for composite preparation and the influence of the tarry material on the strength of the prepared C/C composite was examined. The C/C composites were prepared as follows: the tar was first added over particles of coke or char at room temperature, subsequently, the mixture was pyrolyzed at a predetermined temperature (500-900 degrees C) in an inert atmosphere. The indirect tensile strength of the C/C composite prepared at a pyrolysis temperature of 500 degrees C increased with increasing weight ratio of tar to cokes (3.5-4.5 MPa) or chars (2.0-3.0 MPa) up to a ratio of 2.0; at this point, the indirect tensile strength reached approximately 6.0 MPa. The indirect tensile strength of the C/C composites prepared with the weight ratio of tar to cokes/chars of 2.0 also increased with increasing pyrolysis temperature, reaching approximately 7.0-7.5 MPa at 800-900 degrees C, which was comparable to the ca. 7.0 MPa strength of the high-grade cokes (DI6150 = 87) used in commercial blast furnaces. Based on pore size distribution measurements using the mercury intrusion porosimetry, N-2 adsorption, and polarized optical microscope methods, it was likely that the increase in the indirect tensile strength of the prepared C/C composite occurred because of the vapor infiltration of tar-derived carbonaceous materials into the micro-, meso-and macro-pores in the low-grade cokes and pyrolyzed chars during the pyrolysis of the mixtures.
  • Yuuki Mochizuki, Naoto Tsubouchi, Tomohiro Akiyama
    FUEL PROCESSING TECHNOLOGY 176 21 - 32 2018年07月 [査読有り]
     
    Optimum conditions for preparing carbon-containing pellets with a high crushing strength and high reactivity using three kinds of cold-bonded pellets (CPs) prepared by different methods are investigated in this study. The carbon-containing pellets, which have a size fraction suitable for blast furnace are prepared by completely filling the pores in CPs with carbonaceous materials derived from coke oven gas (COG) tar by the vapor deposition (VD) method. A flow-type quartz fixed-bed reactor is used for this method, using a combination of tar pyrolysis at 700 degrees C and VD at 350 degrees C. The changing pore size distribution, distribution of the carbonaceous material, and crushing strength of the VD samples are then measured for the prepared composites. The carbonaceous materials derived from COG tar completely fills into the mesopores and macropores of the CPs, which is prepared by using Portland cement (PCB) or Carboxymethyl cellulose (CMC), as the binder, and the aging method in stainless-steel container, with increasing VD treatment time. When PCB is treated by the VD method, the C content and crushing strength tends to increase with increasing VD treatment time, and reached 16 wt%-dry and 45 daN, respectively, until 60 min; these values are comparable to the strength of metallurgical-coke with DI6150 = 87.1. Additionally, carbonaceous materials are uniformly deposited in the particles inside. The changes in the reduction behavior and crushing strength of the prepared VD sample under various heat conditions (simulation values in experimental-blast furnaces in COURSE50 project). The reduction extent of the VD samples prepared from PCB reaches up to 30-40% at 850 degrees C. These rates increase above 850 degrees C and attain a value > 95% until 950 degrees C irrespective of the heating and atmospheric conditions. Fe2O3 and Fe3O4 in the VD samples are reduced to FeO and/or alpha-Fe until 850 degrees C under any condition used, while FeO is completely reduced to alpha-Fe by 950 degrees C. The cold crushing strength of VD samples is maintained up to 850 degrees C. Although this value drastically decreases at 900 degrees C, which is the temperature at which alpha-Fe formation occurred, there is no decrease in strength for the reduction of Fe2O3 to Fe3O4, which has been observed reduction disintegration occurs in a conventional blast furnace.
  • Naoto Tsubouchi, Megumi Nishio, Yuji Shinohara, Javzandolgor Bud, Yuuki Mochizuki
    FUEL PROCESSING TECHNOLOGY 176 76 - 84 2018年07月 [査読有り]
     
    The optimum conditions for the production of high-surface-area activated carbon from peat were examined in a fixed-bed quartz reactor by using natural soda ash (> 99 mass% Na2CO3) as the activation agent and urea (CH4N2O) as the nitrogen source. In the heating of the peat/urea/Na2CO3 mixture, the surface area of activated carbon significantly increased when the temperature was higher than 700 degrees C, and it reached 940 and 1100 m(2)/g at 800 and 900 degrees C, respectively. When the mixture was also held at 700 and 800 degrees C for 1 h, the surface area drastically increased from 100 m(2)/g without holding treatment to 730 m(2)/g at 700 degrees C, and it became 1050 m(2)/g at 800 degrees C. The effect of the peat/urea/Na2CO3 mixing ratio on the increase in surface area was investigated. The ratio of urea to Na2CO3 was fixed at 1/2 and the proportion of peat was varied in the range of 0.5-2; the surface area was maximum when peat = 1. In another case, the ratio of peat to urea was fixed at 1/1 and the proportion of Na2CO3 was varied in the range of 1-4. In this case, the surface area was maximum (940 m(2)/g) when Na2CO3 = 2 but decreased when Na2CO3 = 4. On the other hand, when the ratio of peat to Na2CO3 was fixed at 1/2 and the proportion of urea was varied in the range of 0.5-3, the surface area markedly increased up to urea = 1; however, a significant increase did not take place thereafter, even when the proportion of urea was increased. According to these results, the optimum mixing ratio of peat/urea/Na2CO3 and heat treatment conditions to produce high-surface-area activated carbon from peat may be 1/1-3/2 and holding at 800-900 degrees C for 0-1 h, respectively.
  • Naoto Tsubouchi, Yuuki Mochizuki, Yuji Shinohara, Akiyuki Kawashima, Yasuo Ohtsuka
    ENERGY & FUELS 32 6 6970 - 6977 2018年06月 [査読有り]
     
    A model carbon prepared from phenolic resin was activated with 02 and then impregnated with Ca, Cu, or Zn to examine the relationship between the amount of HCl desorbed from carbon samples containing various metals in this lower temperature range (100 and 300 degrees C) and clarified the effect of active sites on HCl adsorption. The results showed that interactions between HCl and carbon were enhanced at temperatures in the range of 100-300 degrees C and that the amount of HCl reacted was increased by doping with these metals. The different HCl concentration profiles at 100 and 300 degrees C were obtained with a greater overall decrease in HCl at the lower temperature (100 degrees C). Those are attributed to increased physical adsorption of HCl at 100 degrees C. The mass of HCl reacted increased in the order of Cu < Ca < Zn at 300 degrees C and Ca < Cu < Zn at 100 degrees C, and HCl reacted at 300 degrees C was evidently more stable than that reacted at 100 degrees C. Organochlorine compounds, chemisorbed HCl, and inorganic chlorides were all identified on the carbon surfaces following exposure to a flow of HCl. The organochlorine species and chemisorbed HCl were desorbed, along with the generation of H2O, upon heating the samples to 700 degrees C, while inorganic chlorides and additional H2O were desorbed above this temperature. Both the mass of organochlorines generated and the amount of HCl absorbed were found to increase with the number of active sites at 300 degrees C; however, that was exceeded remarkably at 100 degrees C.
  • Yuuki Mochizuki, Ryo Naganuma, Naoto Tsubouchi
    ENERGY & FUELS 32 2 1657 - 1664 2018年02月 [査読有り]
     
    The effect of various oxygen-containing compounds added and/or inherent O-species on coal fluidity and coke strength has been investigated in detail. When several O-containing compounds, which have different O-containing groups, are added independently to caking coal, the MF value almost decreases, and the extent of the decrease being ether < ketone < lactone < hydroxyl < acid anhydride < ether/hydroxyl/lactone < carboxyl group. The COOH content in four coals used increases with decreasing C%, and the MF values decrease with increasing the content. The evolution of gaseous O-containing species (CO, CO, and H2O) during carbonization at 3 degrees C/min of four coals up to 400 degrees C has been studied mainly with a flow type quartz-made fixed-bed reactor to clarify the effect of the amount of O-containing gases evolved with the Gieseler fluidity of coal particles. A positive correlation is found between the amount of CO, CO, or H2O evolved up to 400 degrees C and the COOH content in coal. However, a negative correlation between MF and O-containing gases evolved up to 400 degrees C is observed. It is suggested that the COOH amount and/or O-containing gases evolved have adverse effects on the thermoplasticity of coal. When the indirect tensile strength of coke prepared from pelletized samples is plotted against MF values, a positive correlation is found, whereas an inverse correlation is observed between the indirect tensile strength and COOH in coals used or the O-containing gases evolved up to 400 degrees C during carbonization. These observations indicate that some of the oxygen-functional groups naturally present in coal have a negative effect on coal fluidity and that this effect is particularly strong in carboxyl, which can readily be decomposed into gaseous oxygen-containing species during heating up to the initial softening temperature.
  • Yuuki Mochizuki, Naoto Tsubouchi, Tomohiro Akiyama
    ISIJ INTERNATIONAL 58 3 460 - 468 2018年 [査読有り]
     
    Influences of the vapor deposition (VD) atmosphere on the nitrogen/sulfur contents in carbon-containing pellet and the crushing strength during preparation by VD method of coke oven gas (COG) tar against cold-bonded pellet (CP) are first investigated using a flow-type quartz made fixed-bed reactor and a tensile and compression crushing machine. Although N in NH3 that is fed with simulated-COG components is not transferred into the prepared VD sample, some part of the S in H2S moves the VD sample; the carbonaceous materials derived from COG tar fill the pores of the CP. However, these elements do not affect the crushing strengths of the prepared VD samples. The N and S forms in the VD sample are then investigated using XRD and XPS, and the results show that these elements mainly exist as organic-N and-S in the VD samples. The fates of N and S in the VD sample during the reduction process are examined using a flow type fixed-bed reactor under inert (He) and reduction (55%H-2/He) atmospheres. The N species in the samples mainly evolve as NH3 and N-2 at 400-1 000 degrees C, and the cumulative amount of N-2 that evolves is greater than that of NH3. The H2S evolution begins at 400 degrees C, and the profile provides the main peak at approximately 800 degrees C. The amount of evolved H2S in 55%H-2/He is greater than that in He. Although the reduction of the VD sample starts at approximately 400 degrees C and stops at 1 000 degrees C, N and S species in the sample do not affect the reduction rate. In addition, the N and S in the VD samples do not influence the crushing strengths during heat treatment.
  • Naoto Tsubouchi, Yuuki Mochizuki, Yuji Shinohara, Yuu Hanaoka, Takemitsu Kikuchi, Yasuo Ohtsuka
    ENERGY & FUELS 32 1 226 - 232 2018年01月 [査読有り]
     
    Ca2+ and Na+ cations were separately or consecutively ion-exchanged with an Indonesian low-rank coal using saturated aqueous solutions of Ca(OH)(2) and/or soda ash at 20-40 degrees C without pH adjustment. This was done by adding aqueous solutions of the soda ash and/or calcium hydroxide to a dispersion of coal particles in deionized water, while monitoring the Na+ and Ca2+ concentrations and pH of the resulting mixture. A 3.5 mass % Ca2+-exchanged coal, a 1.6 mass % Na+-exchanged coal and a 3.8 mass % Ca2+- and 1.0 mass % Natexchanged coal were obtained. The catalytic pyrolysis and subsequent gasification of these ion-exchanged specimens were performed in a fixed bed quartz reactor at 650, 700, or 750 degrees C. Xray diffraction analyses of the samples pyrolyzed at 700 degrees C found no evidence of Na or Ca species, indicating that these were present as nanoscale particles. The Ca2+/Na+-exchanged coal underwent steam gasification more readily than the other samples, with complete char conversion of this material following 1 h of processing at 700 degrees C. The use of a binary metal catalyst was also found to lower the required reaction temperature by more than 100 degrees C.
  • Naoto Tsubouchi, Yuuki Mochizuki, Yanhui Wang, Yasuo Ohtsuka
    ISIJ INTERNATIONAL 58 2 227 - 235 2018年 [査読有り]
     
    Pyrolysis of 29 coals with carbon contents of 71-92 mass% on a dry, ash-free basis (daf) has been performed mainly in a temperature-programmed mode at 10 degrees C/min up to 800 degrees C with a flow-type fixed bed quartz reactor, and some factors controlling HO formation have been examined. The rate profiles of HCI formation exhibit at least three distinct peaks at around 260-360, 470-510 and 580-630 degrees C, and the lowest temperature peak is present for 8 coals alone, whereas the middle and highest temperature peaks are common with almost all of the coals. The HCI profile is also affected by the size of coal particles and the height of coal particles in the fixed bed. Yields of HCI and char-CI at 800 C for 28 coals except an American bituminous coal are 44-95 and 4-54%, respectively, and tar-CI is as low as 7% in all cases. The chlorine distribution is almost independent of the heating rate in the range of 2.5-400 degrees C/min and has no distinct relationship with carbon or chlorine content in coal, but HCI tends to increase with increasing amount of (Na + 2Ca) in coal with a corresponding decrease in char-Cl. When an Indonesian sub bituminous coal is injected into an 02-blown entrained bed gasifier under pressure, there is an almost 1:1 relationship between carbon and nitrogen conversions, whereas the sulfur and chlorine are enriched in the remaining char, and the degree of the enrichment is higher with chlorine. The method of evaluating coal CI forms quantitatively using model chlorine compounds is proposed.
  • Yuuki Mochizuki, Megumi Nishio, Naoto Tsubouchi, Tomohiro Akiyama
    ENERGY & FUELS 31 9 8877 - 8885 2017年09月 [査読有り]
     
    The optimum conditions for the preparation of carbon-containing pellets (composites) in which the carbonaceous materials derived from coke oven gas (COG) tar are completely filled into the pores of cold-bonded pellets (CPs) by vapor deposition are first investigated using a flow-type quartz fixed-bed reactor. The distribution of carbonaceous material and the crushing strength of the composites are then investigated against prepared composites by means of N-2 adsorption measurements, scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy, and a tensile and compression testing machine. The maximum crushing strength of 10 daN is observed in the case of the composite prepared by a combination of tar pyrolysis at 700 degrees C and vapor deposition at 350 degrees C; this value matches the maximum crushing strength of commercial metallurgical coke with the same size fraction. Moreover, the 2 nm pores observed in the original CP are absent in the prepared composite. Carbonaceous material derived from tar is detected inside the particles and on the particle surface, and the C form is almost amorphous C. Furthermore, the reduction behavior and crushing strength of the composites are examined in a He or 55% H-2/He atmosphere. The reduction rate of the prepared composite is greater than that of a mixture of dehydrated CP and coke in He. In addition, the extent of reduction in 55% H-2/He is larger than that in He. The crushing strengths of the lump ore decrease drastically up to 50% reduction, whereas that of the composites is maintained up to a reduction rate of 50%.
  • Yuuki Mochizuki, Naoto Tsubouchi
    ENERGY & FUELS 31 8 8087 - 8094 2017年08月 [査読有り]
     
    The hydrogen sulfide (H2S) removal performance.of limonite in the presence.of coke oven gas (COG) components (H-2, CH4, CO, CO2, and H2O) has been studied in.a cylindrical flow-type quartz-made fixed-bed reactor at 300-800 degrees C under a high space velocity of 51,000 h(-1) to develop a novel hOt gas cleanup method. The H2S removal behavior by reduced limonite in He does not change at the temperatures examined. On the other hand, the breakthrough curves in 50%H-2/He depend on the temperature; and high performance is found at lower temperatures. An investigation of the breakthrough curves of H2S in the presence of COG,components at 300-600 degrees C reveals that the addition of 30%CH4-14 to 50%H-2/He does not influence the performance below 500 degrees C, whereas the coexistence of 5%CO with 50%H-2/He drastically clecreaseS the H2S removal ability of reduCed,limonite. In addition, the breakthrough curves in 5%CO2 coexisting with 50%H-2/30%CH4/5% CO/He are similar to those of 50%H-2/30%CH4/5%CO/He. However, the addition of 5%H2O to 5Q%H-2/30%CH4/5%CO/He dramatically improves the H2S removal performance of reduced limonite. Similar tendencies are observed in simulated COG (50%H-2/30%CH4/5%CO2/5%H2O/He). Furthermore, the H2S breakthrough curve strongly depends 'on the space velocity.
  • Yuuki Mochizuki, Ryo Naganuma, Kazuya Uebo, Naoto Tsubouchi
    FUEL PROCESSING TECHNOLOGY 159 67 - 75 2017年05月 [査読有り]
     
    The fluidity performance of blended coals prepared from caking coal and non- or slightly-caking coal of different particle sizes, and the evolution of gaseous oxygen containing compounds (CO, CO2 and H2O) during carbonization are examined using the Gieseler plastometer method, and a flow-type fixed-bed quartz made reactor, respectively. The heating rate and temperature are 3 C/min and 1000 degrees C, respectively. The Gieseler fluidity decreases with increasing blend ratio of non- or slightly-caking coal to caking coal. In addition, the fluidity tends to decrease with the decreasing particle size of non- or slightly-caking coal in blended coals. The evolution of CO, CO2 and H2O during the carbonization of single Coals begins at 200-400 degrees C, and the main peak of the formation rate appears at 450-700 degrees C. The amount of gaseous O-containing compounds evolved until 1000 degrees C from the non- or slightly-caking coals is greater than that of evolved from the caking coal. Additionally, a negative correlation is observed between the amounts of CO, CO2, and H2O that evolve up to the initial softening temperature and the maximum fluidity value. The profiles of formation rates of the three gaseous O-containing compounds from the blended coal during carbonization are different with additive average based on the results of single coals. Furthermore, for the blended coal, the starting temperature H2O evolution measured shifts to higher temperature in comparison with that of calculated based on the results of single coals. Therefore, it is possible that the H2O produced from non- or slightly-caking coal in blended coal or that the H2O formation reactions in blended coal during carbonization affects the fluidity performance of the blended coal. (C) 2017 Elsevier B.V. All rights reserved.
  • Tsubouchi Naoto, Mikawa Yusuke, Mochizuki Yuuki, Kikuchi Takemitsu, Ohtsuka Yasuo
    Energy & Fuels 31 4 3885 - 3891 2017年04月20日 [査読有り]
  • Naoto Tsubouchi, Yuuki Mochizuki, Enkhsaruul Byambajav, Satoko Takahash, Yuu Hanaoka, Yasuo Ohtsuka
    ENERGY & FUELS 31 4 3898 - 3904 2017年04月 [査読有り]
     
    Catalytic decomposition of toluene (C6H5CH3) or benzene (C6H6) with inexpensive limonite ores, composed mainly of goethite (alpha-FeOOH), was examined using a vertical, cylindrical flow fixed-bed quartz reactor to develop a novel method of removing biomass-derived tar components. The unsupported limonite catalyst was active for the decomposition of 480 ppm of C6H5CH3 and 1700 ppm of C6H6 in 15 vol % H2O/45 vol % H-2/He, leading to C6H5CH3 and C6H6 conversions at 500 degrees C of nearly 100 and 97%, respectively. When the C6H5CH3 decomposition temperature was increased from 500 to 800 degrees C, the overall reaction path changed from demethylation to hydrocracking and then to steam reforming. A honeycomb-supported limonite catalyst also was effective and achieved nearly complete C6H5CH3 conversion at 600 degrees C. In addition, the honeycomb supported catalyst promoted C6H6 conversion of nearly 100% without carbon deposits at 700 degrees C in 15 vol % H2O/20 vol % H-2/26 vol % CO/20 vol % CO2/5 vol % CH4 that was designed to simulate raw fuel gas derived from biomass gasification. Powder X-ray diffraction (XRD) measurements after reaction at 700-800 degrees C revealed the presence of finely dispersed metallic iron (alpha-Fe), which is likely responsible for the high catalytic performance.
  • Naoto Tsubouchi, Yuuki Mochizuki, Enkhsaruul Byambajav, Yuu Hanaoka, Takemitsu Kikuch, Yasuo Ohtsuka
    ENERGY & FUELS 31 3 2565 - 2571 2017年03月 [査読有り]
     
    Ion-exchange reactions of brown and sub-bituminous coals with natural soda ash, composed of >99% Na2CO3, have been studied at 20-40 degrees C without any pH-adjusting reagents, and the pyrolysis and subsequent steam gasification of the resulting Na+-exchanged coals have been conducted using a fixed-bed quartz reactor at 700 degrees C. When the Na+ concentration and pH of an aqueous mixture of coal and soda ash are monitored during the ion-exchange process, both values decrease at a greater rate with brown coal with a higher content of COOH groups, indicating that ion exchange of Na+ with H+ of the COOH group is the predominant process. About 65% of COOH can be exchanged with Na+ ions under optimal conditions, irrespective of the coal type. The reactivity of these raw coals in steam at 700 C-degrees is similar, with char conversions of less than 20 mass %, even after 2 h of reaction. Exchanged Na promoted the gasification of both coals at this temperature, but the rate profiles were different: conversion of brown coal increased linearly with time and reached nearly 100% at 1 h, whereas sub-bituminous coal needed approximately 2 h to be gasified completely. The temperature dependence of the conversion with this coal revealed that the use of a Na catalyst can lower the reaction temperature by about 120 degrees C, and the apparent activation energies were estimated to be 190 and 120 kJ/mol without and with the catalyst, respectively, from Arrhenius plots of the initial specific rate. The scanning electron microscopy-electron probe microanalysis and X-ray diffraction analysis of Na-containing chars recovered after pyrolysis and gasification suggested that the Na catalysts were finely dispersed at the initial stage of the reaction but that they may be deactivated by the formation of sodium silicates at high char conversions at temperatures higher than 90%, even at the low temperature of 700 degrees C.
  • Javzandolgor Bud, 西尾 恵, 望月 友貴, 坪内 直人
    日本エネルギー学会大会講演要旨集 26 254 - 255 一般社団法人 日本エネルギー学会 2017年 

    The optimum preparation conditions of high-surface-area activated carbon (AC) from peat, urea and natural soda ash have been investigated with a flow-type quartz-made fixed bed reactor. Heating rate and pyrolysis temperature are 10 °C/min and 500-900 °C, respectively. The BET surface area of AC prepared from the mixture of peat/urea/Na2CO3 with mass ratio of 1.0/1.0/2.0 increases with increasing temperature and reaches about 1000 m2/g at 800 °C. When peat/urea/Na2CO3 mixing ratio is changed to 0.5-2.0/0.5-3.0/1.0-4.0, the surface area of AC prepared increases with increasing amount of urea. The N content of AC precursor strongly affects the surface area of AC. In addition, the XRD analyses of AC prepared show that the peak intensity attributable to C(002) increases with increasing temperature. It is thus likely that the optimum heat treatment temperature and mixing ratio are 800 °C and peat/urea/Na2CO3 = 1.0/1.0-3.0/2.0, respectively.

  • Yuuki Mochizuki, Ayumu Ogawa, Naoto Tsubouchi
    ISIJ INTERNATIONAL 57 3 435 - 442 2017年 [査読有り]
     
    Hydrogen sulfide (H2S) removal and catalytic ammonia (NH3) decomposition performance of limonite in the presence of coke oven gas (COG) components has been studied in a cylindrical quartz reactor at 300-850 degrees C under a high space velocity of 51 000 h(-1) to develop a novel hot gas cleanup method. The H2S removal behavior in 50% H-2/He depends on the temperature, with high performance observed at lower temperature. An investigation of the removal behavior of H2S in the presence of COG components (CH4, CO, CO2 and H2O) at 400 degrees C reveals that CH4 does not affect the removal performance. On the other hand, the coexistence of CO drastically decreases the H2S removal performance. However, the addition of 5% H2O to 50% H-2/30% CH4/5% CO/He dramatically improves the H2S removal performance, whereas the performance is low at 5% CO2 with 50% H-2/30% CH4/5% CO/He. In addition, the H2S breakthrough curve strongly depends on the space velocity.The limonite catalyst achieves almost complete decomposition of NH3 in He at 850 degrees C until 240 min. When the decomposition run is performed in the presence of COG components, the coexistence of 30% CH4 deactivates limonite with significant formation of deposited carbon. On the other hand, the addition of 5% CO2, 5% H2O or 5% CO2/5% H2O to 50% H-2/30% CH4/5% CO improves the catalytic activity without carbon deposition, and >99% conversion of NH3 to N-2 is maintained until 240 min.
  • Naoto Tsubouchi, Yuuki Mochizuki, Yanhui Wang, Yasuo Ohtsuka
    TETSU TO HAGANE-JOURNAL OF THE IRON AND STEEL INSTITUTE OF JAPAN 103 8 443 - 450 2017年 [査読有り]
     
    Pyrolysis of 29 coals with carbon contents of 71-92 mass% on a dry, ash-free basis (daf) has been performed mainly in a temperature-programmed mode at 10 degrees C/min up to 800 degrees C with a flow-type fixed bed quartz reactor, and some factors controlling HCI formation have been examined. The rate profiles of HCI formation exhibit at least three distinct peaks at around 260-360, 470-510 and 580-630 degrees C, and the lowest temperature peak is present for 8 coals alone, whereas the middle and highest temperature peaks are common with almost all of the coals. The HCI profile is also affected by the size of coal particles and the height of coal particles in the fixed bed. Yields of HCI and char-CI at 800 degrees C for 28 coals except an American bituminous coal are 44-95 and 4-54%, respectively, and tar-Cl is as low as <= 7% in all cases. The chlorine distribution is almost independent of the heating rate in the range of 2.5-400 degrees C/min and has no distinct relationship with carbon or chlorine content in coal, but HCI tends to increase with increasing amount of (Na + 2Ca) in coal with a corresponding decrease in char-Cl. When an Indonesian sub-bituminous coal is injected into an 02-blown entrained bed gasifier under pressure, there is an almost 1:1 relationship between carbon and nitrogen conversions, whereas the sulfur and chlorine are enriched in the remaining char, and the degree of the enrichment is higher with chlorine. The method of evaluating coal-CI forms quantitatively using model chlorine compounds is proposed.
  • Naoto Tsubouchi, Yuuki Mochizuki, Naoyuki Iwabuchi, Yuuki Akama, Yasuo Ohtsuka
    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 252 2016年08月 [査読有り]
  • Yuuki Mochizuki, Megumi Nishio, Jun Ma, Naoto Tsubouchi, Tomohiro Akiyama
    ENERGY & FUELS 30 8 6233 - 6239 2016年08月 [査読有り]
     
    The optimum conditions for preparing carbon-containing iron ore (composites), in which coke-oven-gas-tar derived carbonaceous materials completely filled the pores in Indonesian limonite (IL), are investigated using impregnation (IM) and vapor deposition (VD). A peak around 2 inn is observed in the pore size distribution profiles for the as-received IL and IL absolutely heated to a predetermined temperature. The intensity of the peak decreased with increasing ratio of tar to IL (tar/IL) for the IM-prepared composites; and it completely disappeared for the composites prepared with tar/IL > 1.0; the corresponding S-BET and V-BJH are < 1 m(2)/g and < 0:01 cm(3)/g, respectively. The peak at 2 nm in the pore size distribution profiles for the VD-prepared composites almost disappears for treatment times longer than 60 min for any combination of conditions for tar pyrolysis temperature (TPT) and VD temperature (VDT). The composite prepared using a combination of TPT-VDT of 700-350 degrees C for 60 min shows the highest carbon content and crushing strength. The C content and crushing strength of the IM- and VD-prepared composites increase with increasing tar/IL and VD time. The composite prepared with tar/IL = 3.0 and VD time of 240 min shows a C content and crushing strength of 48-50 wt %-dry and 10 daN, respectively. The cross-sectional analyses, of composite particles prepared using both methods show that the tar-derived carbonaceous materials has completely filled the pores.
  • Naoto Tsubouchi, Megumi Nishio, Yuuki Mochizuki
    APPLIED SURFACE SCIENCE 371 301 - 306 2016年05月 [査読有り]
     
    The present work focuses on the role of nitrogen in the development of pores in activated carbon produced from lignin by K2CO3 activation, employing a fixed bed reactor under a high-purity He stream at temperatures of 500-900 degrees C. The specific surface area and pore volume obtained by activation of lignin alone are 230 m(2)/g and 0.13 cm(3)/g at 800 degrees C, and 540 m(2)/g and 0.31 cm(3)/g at 900 degrees C, respectively. Activation of a mixture of lignin and urea provides a significant increase in the surface area and volume, respectively reaching 3300-3400 m(2)/g and 2.0-2.3 cm(3)/g after holding at 800-900 degrees C for 1 h. Heating a lignin/urea/K2CO3 mixture leads to a significant decrease in the yield of released N-containing gases compared to the results for urea alone and a lignin/urea mixture, and most of the nitrogen in the urea is retained in the solid phase. X-ray photoelectron spectroscopy and X-ray diffraction analyses clearly show that part of the remaining nitrogen is present in heterocyclic structures (for example, pyridinic and pyrrolic nitrogen), and the rest is contained as KOCN at <= 600 degrees C and as KCN at >= 700 degrees C, such that the latter two compounds can be almost completely removed by water washing. The fate of nitrogen during heating of ligniniurea/K2CO3 and role of nitrogen in pore development in activated carbon are discussed on the basis of the results mentioned above. (C) 2016 Elsevier B.V. All rights reserved.
  • Naoto Tsubouchi, Yuuki Mochizuki, Naoyuki Iwabuchi, Yuuki Akama, Yasuo Ohtsuka
    ENERGY & FUELS 30 5 4381 - 4383 2016年05月 [査読有り]
  • Naoto Tsubouchi, Yuuki Mochizuki, Ryo Naganuma, Kyohei Kamiya, Megumi Nishio, Yohei Ono, Kazuya Uebo
    Energy and Fuels 30 3 2095 - 2101 2016年03月17日 
    The evolution of gaseous oxygen-containing species (CO, CO2, and H2O) during carbonization of 10 types of caking coals has been investigated mainly using a fixed-bed quartz reactor to reveal the influence of inherent oxygen species on the Gieseler fluidity of the coal particles. The heating rate and temperature were 3 °C/min and 1000 °C, respectively. CO evolution apparently started after 350 °C, and the rate profile for CO evolved showed the main or shoulder peak at about 650 °C in many cases. On the other hand, CO2 started to evolve at low temperatures of 200-250 °C for almost all of the coals, and the profile for the rate of CO2 evolution exhibited a main peak at 400-450 °C and a shoulder or small peak at about 600 °C in all cases. H2O formation occurred significantly between 400 and 800 °C, irrespective of coal type. The Gieseler fluidity analyses also revealed that the initial softening, maximum fluidity (MF), and resolidification temperatures of the 10 coals were in the ranges of 375-435, 435-480, and 450-505 °C, respectively, and the MF values were 0.78-4.1 log(ddpm). Interestingly, the MF values tended to decrease with increasing total amount of CO, CO2, or H2O up to the initial softening temperature mentioned above. Further, the addition of oxygen-containing compounds [phthalide (C8H6O2), 2-naphthoic acid (C11H8O2), and fluorescein (C20H12O5)] to an Australian caking coal decreased the MF value considerably specifically, the value decreased from 2.2 log(ddpm) originally to 0.28-1.5 log(ddpm), and the degree of decrease was greatest with 2-naphthoic acid containing -COOH. In contrast, benzofuran (C8H6O) mixed with the coal did not affect the MF value significantly. These observations indicate that some of the oxygen-containing functional groups naturally present in coal have a negative effect on coal fluidity and suggest that this effect is particularly strong for carboxyl and/or acid anhydride groups, which can be readily converted to gaseous oxygen-containing species during heating to the initial softening temperature.
  • Yuuki Mochizuki, Megumi Nishio, Naoto Tsubouchi, Tomohiro Akiyama
    ENERGY & FUELS 30 3 2102 - 2110 2016年03月 [査読有り]
     
    The crushing strength and reduction rate of a carbon-containing pellet (composite) prepared from a cold-bonded pellet (CP) and coke oven gas (COG) tar are examined. The peak of the pore size distribution profile, at approximately 2 nm, observed in the as -prepared CP decreases with the increase in the mixture ratio of tar to CP and completely disappears for the composites prepared above a mixture ratio of 1.0, and the SBET and 'NH values are <1 m(2)/g and <0.01 cm(3)/g, respectively. The crushing strength of the composites increases with the increase in the mixture ratio of tar to CP and becomes 10 daN from 1.0 daN, above a mixture ratio of 2.0. Carbonaceous material derived from tar is detected on the surface of the composite particle, as well as inside the particle, and the C content in the composite is 22 mass%-C. When the composites are heated in He and 55% H-2/He, the evolution of CO, CO2, and H2O starts at approximately 400 and 500 degrees C, respectively, and the formation profiles indicate a large peak at approximately 800-900 degrees C. The extent of reduction of the composites at 1000 degrees C is 85-95%. The crushing strength of the dehydrated-CP decreases drastically up to a reduction extent of 50%, whereas the strength of the composites is maintained at a reduction rate up to 50% and then decreases with the increase in the reduction rate.
  • Yuuki Mochizuki, Megumi Nishio, Naoto Tsubouchi, Tomohiro Akiyama
    FUEL PROCESSING TECHNOLOGY 142 287 - 295 2016年02月 [査読有り]
     
    The crushing strength and reactivity of carbon-containing iron-ore composites prepared from cold-bonded-pellet derived from steel-making dust (DP) and coke oven gas tar, is examined with a flow-type fixed-bed quartz-made reactor and with a tensile- and compression-testing machine, respectively. When an as-received DP is heated via temperature-programmed heat treatment in He, the intensity of pore-size-distribution peak at 2 nm, specific surface area (S-BET) and pore volume (V-BJH) in the as-received DP tend to decrease with increasing temperature, and the latter two values in the sample, when heated up to 500 (DP/500) and 900 degrees C (DP/900) become 20 and 5 m(2)/g and 0.06 and 0.01 cm(3)/g, respectively. The peak of the pore size distribution profile around 2 nm completely disappears for the composites prepared from the DP, DP/500 and DP/900, and the S-BET and V-BJH values in all the composites are <1 m(2)/g and <0.01 cm(3)/g, respectively. The crushing strengths of the composites are greater than those of the original samples, measure before the preparation of the composites. The order of the crushing strengths of the composites is similar to that of their V-BJH values. When the composites are heated in He, the evolution of CO, CO2 and H2O start around 400 and 500 degrees C, respectively, and these formation profiles indicate a large peak at about 800-900 degrees C. The extent of reduction of all the composites at 1000 degrees C is 85-95%, and the reduction rate for each composite is greater than that of its original sample. (C) 2015 Elsevier B.V. All rights reserved.
  • 望月 友貴, 坪内 直人, 上坊 和弥
    日本エネルギー学会大会講演要旨集 25 8 - 9 一般社団法人 日本エネルギー学会 2016年 

    Carbon/carbon composites are prepared in the following manner : COG tar recovered from a commercial coke oven is first mixed with low grade cokes or pyrolyzed chars from lignite and sub-bituminous coals, and the resulting mixtures are then heated in He at 10 °C/min up to 500-900 °C with a flow-type fixed bed quartz reactor. The tensile strength of each composite prepared is investigated with a tensile and compression testing machine. The strength increases with increasing weight ratio of tar to coke or char up to about 2, and it becomes approximately 6.0 MPa at this ratio. The strength also increases with increasing pyrolysis temperature up to 800 °C, it reaches about 7.5 MPa, which is comparable to those (7.0 MPa) of high grade cokes used in commercial blast furnaces. On the basis of the results of pore size distribution measurements, it is likely that the increase in the strength takes place as a results of the infiltration of tar-derived carbonaceous materials into pores in low grade cokes and pyrolyzed chars.

  • Ayumu Ogawa, Yuuki Mochizuki, Naoto Tsubouchi
    ISIJ INTERNATIONAL 56 7 1132 - 1137 2016年 [査読有り]
     
    Catalytic performance of limonite in the decomposition of 100 ppmv pyridine (C5H5N) in the coexistence of fuel gas or coke oven gas (COG) components has been studied mainly with a cylindrical quartz reactor at 750-850 degrees C under a high space velocity of 51 000 11-1 to develop a novel hot gas cleanup method of removing the nitrogen in tar as N-2. The limonite catalyst achieves the almost complete decomposition of C5H5N in He at 500-850 degrees C and gives a high N-2 yield of more than 85 N% at 500 degrees C. When the decomposition run is performed in the presence of fuel gas or COG components, the coexistence of 20% CO/10% H-2 at 750 degrees C or 50% H-2/5% CH4/5% CO at 850 degrees C deactivates the limonite with remarkable formation of deposited carbon. On the other hand, the addition of a small amount of H2O or CO2 to these atmospheres can improve the catalytic activity without carbon deposition. When 3% H2O or 10% CO2 is added to 20% CO/10% H-2, C5H5N conversion and N-2 yield at 750 degrees C become 80-95% and 65-80 N%, respectively, and the extent of the improvement is larger with the CO2 than with the H2O. The addition of 5% CO2 to 50% H2/30% CH4/5% CO also restores the conversion or the yield at 850 degrees C to the high level of about 90% or 60-70 N%, respectively, and both values at 950 degrees C are comparable to those at 500 degrees C in inert gas.
  • Yuuki Mochizuki, Naoto Tsubouchi, Tomohiro Akiyama
    FUEL PROCESSING TECHNOLOGY 138 704 - 713 2015年10月 [査読有り]
     
    The reduction behavior and crushing strength of carbon-containing iron ore sinters (SI-C) prepared from coke oven gas (COG) tar have been examined with a quartz-made fixed bed reactor and with a tensile and compression testing machine, respectively. When an as-received iron ore sinter (SI) is heated at 10 degrees C/min up to 600 degrees C in 55% H-2/He, the resulting sample (SI/600) gives a very small, broad pore size distribution profile, the surface area (S-BET) and pore volume (V-BJH) being 1.5 m(2)/g and 0.005 cm(3)/g, respectively. On the other hand, SI-pretreated in 55% H-2/He at 450 degrees C for 4 h (SI-450) provides the pore distribution profile peaking around 10 nm, and S-BET and V-BJH are 4 m(2)/g and 0.02 cm(3)/g, respectively. When carbon-containing iron ore sinters (SI/600-C and SI-450-C) are prepared by pyrolysis of the mixture of the pretreated SI and COG tar, no measurable amounts of S-BET and V-BJH are detectable in any case. The crushing strength of SI-450 is improved significantly by the deposition of tarderived carbonaceous materials into the pores formed during the pre-treatment. In a temperature-programed heat treatment in He, the evolution of CO, CO2 and H2O from the SI-450-C samples start after 600 degrees C, and each rate profile observed shows a large peak around 700-850 degrees C. The extent of reduction of SI-C, SI/600-C or SI450-C is 3, 19 or 55% on SI basis, respectively, and it depends on S-BET and/or V-BJH of the feed sample. (C) 2015 Elsevier B.V. All rights reserved.
  • Naoto Tsubouchi, Yuuki Mochizuki, Naoyuki Iwabuchi, Yuuki Akama, Yasuo Ohtsuka
    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 250 2015年08月 [査読有り]
  • Naoto Tsubouchi, Ayumu Ogawa, Yuuki Mochizuki
    APPLIED CATALYSIS A-GENERAL 499 133 - 138 2015年06月 [査読有り]
     
    Catalytic decomposition of 100 ppmv pyridine (C5 H5N) with an Australian limonite ore, composed mainly of goethite (alpha-FeOOH), has been examined for hot gas cleanup with a fixed-bed quartz reactor at 300-500 degrees C under a large space velocity of 51,000h(-1). When alpha-FeOOH in the limonite is reduced with pure H-2 at 500 degrees C, the transformation into nanoscale particles of metallic iron (alpha-Fe) occurs, and the catalyst achieves almost complete C5H5N decomposition in inert He at 500 degrees C and provides an N-2 yield greater than 80% for at least 10 h. The limonite also exhibits a high catalytic activity at 500 degrees C, even without H-2 reduction. Based on the results of N Is X-ray photoelectron spectroscopy and temperatureprogrammed desorption measurements, it is probable that the limonite-catalyzed formation of Ny from pyridine proceeds through cycle mechanisms involving a-Fe and iron nitride species.(C) 2015 Published by Elsevier B.V.
  • 望月 友貴, 坪内 直人, 秋山 友宏
    石炭科学会議発表論文集 52 2 - 3 一般社団法人日本エネルギー学会 2015年 
    The crushing strength and reduction reactivity of a carbon-containing pellet prepared from a cold bonded pellet (CP) and COG tar have been examined with a tensile and compression machine and with a fixed-bed quartz reactor, respectively. The C-containing pellet is prepared by the chemical vapor infiltration (CVI) method under the conditions of tar pyrolysis temperature of 700℃ and CVI temperature of 350℃. When CP is heated up to 350℃, specific surface area (S_) and total pore volume (VEJB) increase from 20 to 60 m^2/g and from 0.06 to 0.075 cm^3/g, respectively, and the profile for pore size distribution gives a district peak around 2 nm. On the other hand, S_ and V_ values of CVI sample are as low as < 1 m^2/g and < 0.01 cm^3/g, respectively, and the peak observed around 2 nm disappears completely. The crushing strength of the sample reaches 10 daN, and the value is comparable to those of typical metallurgical cokes. The evolution of CO, CO_2 or H_2O starts at 300-400℃, and the maximal rates of these gases evolved are observed around 700-800℃ during heat treatment of the sample in He. The extent of redaction after 60 min holding at 1000℃ reaches > 85%, and metallic-Fe is formed above 800℃.
  • Yuuki Mochizuki, Naoto Tsubouchi, Katsuyasu Sugawara
    KAGAKU KOGAKU RONBUNSHU 41 5 340 - 349 2015年 [査読有り]
     
    To investigate the fate of boron and selenium in low-rank coals during coal combustion, the effects of the dust collector and wet-flue gas desulfurization (FGD) conditions on the distributions of B and Se have been studied with a lab-scale pulverized combustor equipped with an FGD unit. Although the residence time of fly ash (FA) from the furnace inlet to the dust filter does not affect B distribution, the proportion of Se condensed onto the FA increases with increase in the residence time. Further, the proportion of B transferred into the bottom ash (BA) during the combustion of high ash-containing coal is greater than that during the combustion of middle-level ash-containing coal. On the other hand, the amounts of B condensed onto the FA are equal for the two types of coals examined. This result shows that the B distribution during coal combustion strongly depends on the coal type. No such coal type dependence is observed in the case of Se, because almost all of the Se in raw coal transfers into the gas phase during coal combustion, resulting in a very low amount of Se in BA. Examination of the effect of flue gas temperature on B distribution reveals that the gaseous B produced during coal combustion does not condense onto the FA as FA-B in the temperature range of 90-400 degrees C. On the other hand, the amount of gaseous Se decreases with decrease in the flue gas temperature, and gaseous Se condenses onto the FA. We hypothesize that the ash composition in the FA and/or the sulfur content in the flue gas (Ca/S or Fe/S) may affect Se distribution, because the condensation behavior of Se onto the FA is quite different between for high-ash and high-sulfur-containing coals. In addition, it is found that over 90% of the gaseous Se can be removed at a flue gas temperature of 90 degrees C. In the FGD test, almost all of the gaseous B or Se passing through the dust filter is trapped in the FGD solution, and the residual gaseous B or Se transfers into gypsum. The pH or temperature of the FGD solution does not affect B and Se distributions in the FGD unit. It is found that the gaseous B or Se formed during the combustion of pulverized coal can be removed via the flue gas and FGD unit.
  • Naoto Yasuda, Yuuki Mochizuki, Naoto Tsubouchi, Tomohiro Akiyama
    ISIJ INTERNATIONAL 55 4 736 - 741 2015年 [査読有り]
     
    This paper describes the reduction and nitriding behavior of hematite with ammonia in the context of ironmaking. The effects of temperature and ammonia concentration on the products were investigated. In the temperature range from 793 to 863 K, hematite was directly reduced to magnetite by ammonia (1/2Fe(2)O(3) + 1/9NH(3) -> 1/3Fe(3)O(4) + 1/6H(2)O + 1/18N(2)). The ammonia started to decompose at 873 K, triggered by the generation of alpha-Fe. Magnetite was reduced mainly to iron by hydrogen generated from the decomposition of ammonia (1/3Fe(3)O(4) + 4/3H(2) -> Fe + 4/3H(2)O). According to in-situ X-ray diffraction (XRD) measurements, alpha-Fe was immediately nitrided to an epsilon-Fe3-xN (0 <= x <= 1) phase, and the N/Fe atomic ratio decreased gradually with increasing temperatures. The rate of hematite reduction increased with the ammonia concentration for 5% to 20% NH3, but plateaus for NH3 concentrations greater than 20%. This was attributed to the mechanism of ammonia decomposition; the amount of hydrogen generated also plateaus at ammonia concentrations above 20%. The reduction rate was therefore limited by the rate at which hydrogen was generated during ammonia decomposition. The N content of the product was affected not only by the temperature but also by the nitriding potential (K-N = P-NH3/P-H2(3/2)). The nitriding potential increased with increasing ammonia concentrations and decreasing temperatures. The addition of nitrogen gas to the reactive gas inhibited ammonia decomposition and increased the nitrogen potential and N content of the product.
  • Yuuki Mochizuki, Naoto Tsubouchi, Katsuyasu Sugawara
    FUEL 130 54 - 59 2014年08月 [査読有り]
     
    Behavior of boron (B) release and change in the occurrence mode of B during fixed-bed pyrolysis of seven coals with 60-82 mass%-daf C have been studied mainly to understand B chemistry in coal utilization. The sequential leaching experiments of the coals with H2O , CH3COOH (AcOH) and HCl solutions show that the proportion of H2O-soluble B species is higher with lower rank coal with a smaller carbon content (C%), whereas the B insoluble in these solvents exhibits the reverse C% dependence. The density separation of some coals with a sink-float technique also reveals that the concentration of B element tends to increase with decreasing density of coal particles. When each coal used is pyrolyzed at 10 degrees C/min up to 1200 degrees C, the extent of B release depends significantly on the kind of coal and ranges from approximately 5-70%, it at 900 degrees C being lower at a higher content of SiO2 or Al2O3 in coal. About 60-100% of the B present in the chars after pyrolysis at 900 degrees C is insoluble in the above-mentioned three solvents in many cases, and the rest exists in the forms of H2O-and/or AcOH-/HCl-soluble B. In the fixed-bed gasification of the 900 degrees C-chars with CO2 under the conditions of 900 degrees C and 0.1 MPa, char conversion increases with increasing reaction time, but no significant B release is observed in almost all cases. It is thus probable that the B in char is retained and enriched in the residual char even at the latter stage of gasification. (C) 2014 Elsevier Ltd. All rights reserved.
  • Yuuki Mochizuki, Naoto Tsubouchi, Katsuyasu Sugawara
    Journal of Asian Ceramic Societies 2 1 68 - 76 2014年03月 [査読有り]
  • 望月 友貴, 坪内 直人
    石炭科学会議発表論文集 51 60 - 61 一般社団法人日本エネルギー学会 2014年 
    Physical and chemical properties of iron oxide-carbon composites prepared from tar-impregnated limonite ores have been studied in detail. When as-received limonite is heated up to 500℃, the pore size distribution for the resulting sample shows a single peak at the pore diameter of about 2 nm, and total pore volume and specific surface area increase from the original 0.15 cm^3/g and 80 m^2/g to 0.25 cm^3/g and 110 m^2/g, respectively. With the composite produced, on the other hand, the 2 nm-peak described above disappears almost completely, and the volume and area become as low as <0.01 cm^3/g and 1 m^2/g, respectively. The evolution of CO, CO_2 or H_2O from composite samples during heat treatment starts at about 500℃, and the rate profile of each O-containing gas observed exhibits the main peak around 800℃ in every case. The rates of reduction of the composites are much larger than that for the physical mixture of the limonite preheated up to 500℃ and cake.
  • 小川 歩, 望月 友貴, 坪内 直人
    石炭科学会議発表論文集 51 2 - 3 一般社団法人日本エネルギー学会 2014年 
    Catalytic performance of α-FeOOH-rich limonite in the decomposition of 100 ppmv pyridine (C_5H_5N) in different atmospheres under a large space velocity of 51000 h^<-1> has been investigated with a fixed bed quartz reactor to develop a novel hot gas cleanup method of removing the nitrogen in tar as N_2. The limonite catalyst achieves the almost complete decomposition of C_5H_5N in He at 500-750℃ and gives high N_2 yield of more than 80% at least for 10h at 500℃. The limonite is seriously deactivated by cofeeding syngas (20% CO/10% H_2) with C_5H_5N because of carbon deposition from CO. On the other hand, the addition of 10% CO_2 to the syngas improves the catalytic activity and restores the yield at 750℃ to ≥ 80% without carbon deposition.
  • Yuuki Mochizuki, Naoto Tsubouchi, Katsuyasu Sugawara
    KAGAKU KOGAKU RONBUNSHU 40 1 56 - 64 2014年 [査読有り]
     
    Adsorption desulfurization of several organic sulfur compounds in model fuels (tetralin and n-dodecane) by metal (Co, Ni, Cu, Zn, Pb)-loaded carbons was studied with a batch-type Pyrex glass vessel or stainless autoclave at 25-350 degrees C to develop a novel method of removing the sulfur present in coal extract. The results showed that nickel-loaded carbon (Ni/C) has the highest desulfurization performance, but the adsorption depends on the type of model fuel and the kind of sulfur compound. At <200 degrees C, desulfurization was higher in n-dodecane than in tetralin and increased in the order of dibutyldisulfide= 250 degrees C and was larger in tetralin than in n-dodecane. GC-MS analysis following the experiments with DBT revealed the presence of biphenyl, meaning that cleavage of the organic C-S bond in DBT proceeds on Ni/C.
  • Naoto Tsubouchi, Yuuki Mochizuki, Yohei Ono, Kazuya Uebo, Toshimasa Takanohashi, Naoto Sakimoto
    ISIJ INTERNATIONAL 54 11 2439 - 2445 2014年 [査読有り]
     
    The present study focuses on examining the fate of coal-S and coal-N during carbonization in detail and making clear the effects of these elements on coal fluidity and coke strength. When eight kinds of caking coals with 80-88 mass%-daf C are carbonized in high-purity He at 3 degrees C/min up to 1 000 degrees C with a quartz-made fixed bed reactor, 50-75% of coal-S remains as FeS and organic-S in the coke, and the rest is released as tar-S and H2S. Most of coal-N is also retained in the coke, and the remainder is converted to tar-N, HCN, NH3 and N-2. The eight coals give Gieseler maximum fluidity values between 435 and 480 degrees C, and the value tends to be larger at a smaller sulfur content in coal or in the carbonaceous material recovered after carbonization at 450 degrees C. It also seems that the value increases with increasing nitrogen content in coal or total amount of either HCN or NH3 formed up to 450 degrees C. Furthermore, the addition of S-containing compounds to an Australian bituminous coal lowers coal fluidity and coke strength considerably, whereas indole gives the reverse effect on them. On the basis of these results, it is suggested that coal-S or some coal-N has a negative or positive effect on the two properties, respectively.
  • Yuuki Mochizuki, Yohei Ono, Kazuya Uebo, Naoto Tsubouchi
    INTERNATIONAL JOURNAL OF COAL GEOLOGY 120 50 - 56 2013年12月 [査読有り]
     
    The fate of sulfur during carbonization at 3 degrees C/min of seven caking coals with carbon and sulfur contents of 80-88 and 0.55-1.8 mass%-daf, respectively, has been studied using a flow-type fixed-bed quartz reactor to examine its effect on coal fluidity in caking coal. Org.S transfers to H2S or tar-S from 200 to 350 degrees C, and FeS2 decomposes to H2S and FeS above 350 degrees C. The H2S formation rate exhibits two distinct peaks at 450 and 550 degrees C. The amounts of H2S that evolved and Org.S that remained in cokes often depend on carbon contents in raw coals. The maximum fluidity (MF), determined by the Gieseler plastometer method, appears at around 450 degrees C for all of the coals examined, and the values range from 1.1 to 4.1 log(ddpm). The MF value tends to decrease with increasing amounts of FeS2 or Org.S remaining in solid products up to 450 degrees C. Sulfur-containing compounds, such as elemental sulfur, FeS2, diphenyl disulfide and dibenzothiophene, added to caking coal adversely affect coal fluidity. (C) 2013 Elsevier B.V. All rights reserved.
  • Naoto Tsubouchi, Yuuki Mochizuki, Yohei Ono, Kazuya Uebo, Naoto Sakimoto, Toshimasa Takanohashi
    ENERGY & FUELS 27 12 7330 - 7335 2013年12月 [査読有り]
     
    Seven kinds of caking coals with carbon contents of 80-88 wt % dry and ash-free basis (daf) have been carbonized in high-purity He at 3 degrees C/min up to 1000 degrees C with a fixed-bed quartz reactor, and the fate of coal-bound nitrogen (coal N) has been investigated in detail. The nitrogen mass balances fall within 97-104%. Most coal N is retained as quaternary N in the cokes, and the rest is released as volatile N (tar N, HCN, NH3, and N-2). NH3 is the main N species evolved below 650 degrees C, irrespective of the kind of coal, and the profile for the rate of NH3 formation shows the main peak at about 450 degrees C, followed by a small peak at around 670 degrees C in every case. Significant amounts of HCN are also observed below 650 degrees C, and the rate profiles for HCN as well as NH3 exhibit two peaks at around 450 and 670 degrees C, whereas most N-2 is formed at the temperature range of 650-1000 degrees C. The distribution of volatile N at 1000 degrees C is in the order of tar N < HCN < NH3 approximate to N-2 for almost all coals. Each coal used gives a Gieseler maximum fluidity (MF) of 1.1-4.0 log(ddpm) at around 450 degrees C (440-480 degrees C), and it seems that the MF value tends to increase when the total amount of either HCN or NH3 evolved up to 450 degrees C increases.
  • Yuuki Mochizuki, Naoto Tsubouchi, Katsuyasu Sugawara
    ACS SUSTAINABLE CHEMISTRY & ENGINEERING 1 6 655 - 662 2013年06月 [査読有り]
     
    To develop an effective recovery process of rare earth metals from Dy containing Nd2Fe14B magnets (NdFeB-Dy), the release behavior of rare earth metals (Nd and Dy) and coexisting elements (Fe, B, Co, Cu, Zr) from the magnets during chlorination are investigated under the conditions at rate of 30 degrees C/min and predetermined temperatures from 100 to 1000 degrees C in a Cl-2 gas stream. Although coexisting elements volatilize from NdFeB-Dy in the low temperature region, Nd and Dy condense in the chlorination residue obtained up to 1000 degrees C. NdFeB-Dy is preoxidized by heat treatment up 350, 600, and 900 degrees C in air to represent demagnetized and decarbonized samples. While Fe, Co, and Cu in oxidized sample volatilize during chlorination, Zr and B remain with rare earth metals in the oxidation samples during chlorination temperature up to 1000 degrees C. When carbon is added to the oxidation samples, all of the elements, except Nd and Dy, volatilize until 1000 degrees C, thus the rare earth chlorides can be concentrated in the residue after carbochlorination. The rare earth chlorides in the chlorination residues containing carbon can be modified by heat treatment up to 1000 degrees C under steam to recover rare earth oxides.
  • 小川 歩, 望月 友貴, 坪内 直人
    石炭科学会議発表論文集 50 60 - 61 一般社団法人日本エネルギー学会 2013年 
    Catalytic decomposition of pyridine (C_5H_5N) with an Australian α-FeOOH-rich limonite ore has been studied with a vertical, cylindrical quartz reactor to develop a novel hot gas cleanup method of removing the nitrogen present in tar as N_2. The limonite achieves the almost complete decomposition of 100 ppmv C_5H_5N in inert gas at 500℃ under a large space velocity of 51000 h^<-1> and maintains the high activity at least for 10h. The limonite can also give high N_2 yield of more than 85%, and the yield is almost constant for 10h reaction. The XRD analyses reveal that α-FeOOH in the limonite is transformed into metallic iron (α-Fe) with the average crystalline size of 25 nm upon H_2 reduction at 500℃. It is thus probable that the finely dispersed α-Fe can catalyze N_2 formnation from pyridine.
  • Naoto Tsubouchi, Yuuki Mochizuki, Yohei Ono, Kazuya Uebo
    TETSU TO HAGANE-JOURNAL OF THE IRON AND STEEL INSTITUTE OF JAPAN 98 5 11 - 19 2012年05月 [査読有り]
     
    The functionalities of the nitrogen (coal-N) and sulfur (coal-S) present in three caking coals with carbon contents of 76-81 wt%-dry and the fate of these heteroatoms during coal carbonization have mainly been studied by the X-ray photoelectron spectroscopy (XPS) and with a fixed bed quartz reactor, respectively. The XI'S measurements exhibit that about 80-90 % of the coal-N exists as pyrrolic-N and pyridinic-N, and the rest can be assigned to quaternary-N (pyridinic-N associated with the hydroxyl groups from phenols or carboxylic acids), whereas the coal-S consists of thiophenic-S, alkyl-S and FeS2, and the proportion of the former is as high as 60-70 %. When the coal sample is carbonized in He at a heating rate of 3 degrees C/min, yield of N-containing species observed at 1000 degrees C increases in the order of HCN <= tar-N < NH3 < N-2 < oil-N < coke-N, regardless of the type of coal, and the latter two are present predominantly as NH4+ and in polynuclear aromatic structures, respectively. On the other hand, yield of S-containing species at 1000 degrees C increases in the order of COS < CS2 < tar-S < oil-S < H2S < coke-S with all coals, and more than 95 % of the coke-S can be regarded as thiophenic-S. These tendencies are also observed with physical mixtures of each coal investigated. Possible mechanisms for the formation of gaseous N- or S-containing compounds in the carbonization process are discussed on the basis of the results of some thermodynamic calculations.
  • 熊谷 治夫, 望月 友貴, 坪内 直人, 奥山 憲幸, 宍戸 貴洋, 堺 康爾, 濱口 眞基, 小松 信行
    石炭科学会議発表論文集 49 132 - 133 一般社団法人日本エネルギー学会 2012年 
    Compared with the conventional techniques, high temperature proton NMR relaxation measurement enable to monitor the actual changes in progress of thermal transformation. The quantitative change of specimens can be evaluated by recording the hydrogen content of residual specimens, and qualitative variation of the specimen is able to detect as a change of the relaxation characteristics of signal. In this study, thermoplastic properties of coal, coal blend and coal blend with "High Performance Coking additive, HPC" are investigated by means of proton NMR relaxation measurement from the viewpoints of molecular mobility. The solid echo pulse sequence was employed to generate ^1H-NMR transverse relaxation signals. The echo signals obtained during heat treatment under a flow of nitrogen at a heating rate of 3K/min were deconvoluted into a set of one Gaussian and two Exponential decay components which represent the immobile, intermediate and mobile component, respectively. It is demonstrated that ^1H-NMR relaxation measurement is the appropriate dynamic measurement technique to characterize the thermoplastic properties of coal. Thermoplastic phenomenon of coal is evaluated both qualitatively and quantitatively by the variation of IHm and T2Hm. HPC is effective additive to improve the thermoplasticity of coal blend. The improvement of the thermoplasitic phenomenon of coal blend with HPC is attributed to the quantitative and qualitative change of Hm.
  • 望月 友貴, 熊谷 治夫, 坪内 直人, 小野 洋平, 上坊 和弥
    石炭科学会議発表論文集 49 56 - 57 一般社団法人日本エネルギー学会 2012年 
    The fate of the nitrogen and sulfur present in seven caking coals during pyrolysis has been studied with a flow-type fixed-bed quartz reactor to examine the effects of these heteroatoms on coal fluidity. The Gieseler maximum fluidity (MF) appears around 450℃ with all coals. The MF values range from 1.1 to 4.1 log(ddpm) and depend strongly on the type of coal. The evolution of HCN, NH_3, H_2S and tar-S starts after 350℃, whereas char-N, organic-S and FeS_2 decrease beyond 350℃. FeS_2 can readily be transformed to FeS and H_2S at 350-650℃. The evolution amounts of gaseous N- and S-containing species depend on the kind of coal. The MF value tends to increase with increasing total amount of HCN, NH_3 or H_2S evolved up to 450℃. Although the addition of 1 wt% aliphatic-N, inorganic-N or S-containing compounds to coal decreases coal fluidity, but polycyclic aromatic compounds increase the fluidity.
  • Yuuki Mochizuki, Katsuyasu Sugawara
    FUEL 90 10 2974 - 2980 2011年10月 [査読有り]
     
    The objective of this study was to develop an efficient cleaning process for hydrocarbon resources. We investigated the removal of organic sulfur from coal extract by using metal-loaded carbons. Tetralin and tetralin/phenol mixture were used for thermal extraction of Illinois No. 6 coal at 375 degrees C with a holding time of 1 h, and we examined the effects of temperature on product yield and sulfur-removal behavior using metal-loaded carbons. A decrease in the n-hexane insoluble fraction was observed at a temperature range from 200 degrees C to 250 degrees C in the extracts of tetralin and tetralin/phenol mixture. The organic sulfur content in the n-hexane insoluble fraction drastically decreased with increasing temperature. The organic sulfur in the n-hexane insoluble fraction was reduced above 200 degrees C, while the sulfur content reached 30-35% at 375 degrees C for both tetralin and tetralin/phenol mixture extracts. We investigated the effect of holding time on the extent of the coal extract desulfurization using Ni-loaded carbon. The sulfur content in the coal extract decreased as the holding time increased. The rate of coal extract desulfurization using tetralin/phenol was slower than that obtained using tetralin. The coal extract obtained using the tetralin/phenol mixture contained a heavier polar fraction, which may have impeded the adsorption. All organic sulfur in the coal extract could be successfully removed Ni-loaded carbon at a treatment temperature of 350 degrees C and a holding time of 8 h. No appreciable changes were observed in the content of carbon, hydrogen, or nitrogen at any temperature or holding time in the ultimate analysis of the n-hexane insoluble fraction treated with Ni-loaded carbon. The results demonstrated that Ni-loaded carbon was much effective in removing organic sulfurs from the coal extract. (c) 2011 Elsevier Ltd. All rights reserved.
  • Yuuki Mochizuki, Katsuyasu Sugawara
    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 242 2011年08月 [査読有り]
  • Yuuki Mochizuki, Hirosuke Mori, Katsuyasu Sugawara
    KAGAKU KOGAKU RONBUNSHU 37 1 70 - 77 2011年 [査読有り]
     
    In order to obtain fundamental data for developing an efficient recovery process of rare earth elements from Nd-Fe-B magnets, the release behavior of Nd, Pr and elements was investigated under the conditions of heating rate of 30 degrees C/min and terminal temperatures from 100 to 1000 degrees C in a Cl(2) gas stream. Fe and B volatilizedin the low temperature region, while Nd and Pr were concentratedin the solid phase by the chlorination. Nd-Fe-B samples werepre-oxidized by heating at 500 degrees C in air to prevent spontaneous combustion of the fine magnet powder. While Fe and Co in the oxidized magnet were volatilized during the chlorination, the rare earth elements and B mostly remained in the solid phase as water-insoluble forms. When carbon and SiC powders were added to the oxidized sample, Fe, Co and B were completely volatilized at 1000 degrees C by carbochlorination. Nd and Pr were concentrated in the residue of the oxidized magnet sample. It was also found that Nd and Pr could be selectively recovered by leaching with water from the residue, because these elements formed chlorides by the carbochlorination.
  • Yuuki Mochizuki, Takaaki Shoji, Takahiro Kato, Kenji Murakami, Katsuyasu Sugawara
    KAGAKU KOGAKU RONBUNSHU 37 5 454 - 459 2011年 [査読有り]
     
    To obtain fundamental data for developing an efficient recovery process of rare metals from grinding powder and cutting fragment of optical glass, the release of Nb, Ta, La, Gd and coexisting elements (Ti, Zr and Zn) was investigated under the conditions of a heating rate of 30 degrees C/min and terminal temperatures from 200 to 1000 degrees C in a Cl-2 gas stream. The release of Zn, Nb, Ti and La drastically increased above 700 degrees C and attained almost 100% at 1000 degrees C, while that of Zr attained to 10% above 800 degrees C. Carbon addition accelerated the volatilization, and the release of elements other than La and Gd reached 100% by 1000 degrees C. The release of La and Gd was only 2-3% in the temperature from 800 to 1000 degrees C. When the samples were heated at 700 degrees C for 120 min, Ta and Nb were selectively volatilized from solid phase without the release of La and Gd.Based on the experimental results, a three-step heat treatment process at 500, 700 and 1000 degrees C in a Cl-2 gas stream with carbon addition was proposed to recover the rare metals selectively from the optical glass.
  • Yuuki Mochizuki, Katsuyasu Sugawara
    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 239 2010年03月 [査読有り]
  • Yuuki Mochizuki, Katsuyasu Sugawara, Yukio Enda
    ENERGY & FUELS 23 9 4502 - 4506 2009年09月 [査読有り]
     
    Boron is one of the most texie and highly valatile elements present ill coal, As part. of it series of studios carried out oil coal cleaning to prevent environmental problems and to promote efficient coal utilization processes, the removal of boron by leaching with water and acetic acid has been investigated, The effects of the addition of ash components, that is, SiO2, Al2O3, and CaO on the control of boron release during pyrolysis and gasification were investigated. Here, 20-70% or boron in coal was removed by leaching the coal with water and acetic acid. Boron leached by water and acetic acid was related to the volatiles released from coal in pyrolysis below 1173 K. The addition of ash components such as SiO2 and Al2O3 wits found to be effective in suppressing the release of boron during pyrolysis temperatures below and above 1173K, respectively. The addition of CaO to coal was effective in suppressing the release of boron during gasification tit 1173 K.
  • Yuuki Mochizuki, Katsuyasu Sugawara
    ENERGY & FUELS 22 6 3939 - 3943 2008年11月 [査読有り]
     
    In a series of studies on precleaning technology based on sulfur forms, an advanced desulfurization process that can be carried out under mild conditions has been developed for the production of clean sulfur-free fuel. The selectivity of adsorption of various metal compounds to thiols, sulfides, and thiophenes in a model fuel (n-dodecane) at room temperature was investigated. Among the studied metal compounds, lead oxide showed the highest selectivity to both aliphatic and aromatic thiols. The rate of adsorption of thiols on lead oxide depended on the length of the alkyl chain and initial concentration of thiols. X-ray diffraction and Fourier transform infrared measurements indicated that the adsorption form varied with the initial concentration and type of thiols.
  • Yuuki Mochizuki, Katsuyasu Sugawara
    ENERGY & FUELS 22 5 3303 - 3307 2008年09月 [査読有り]
     
    To develop an advanced desulfurization process that can be carried out under mild conditions without pressurized hydrogen or catalysis that has been evaluated for the extraction of thiophenic sulfur from a model fuel using the ionic liquids, 1-alkyl-3-alkyl imidazolium alkyl sulfate at room temperature was investigated. Six types of halogen-free ionic liquids with different alkyl chain lengths were prepared. The extraction yield of dibenzothiophene was higher than that of diphenylsulfide and diphenyldisulfide. The extraction yield of dibenzothiophene increased linearly with an increase in the length of alkyl chains and the mass ratio of the ionic liquid to the model fuel. The effect because of the change in the type of solvent was not appreciable, and dibenzothiophene was efficiently removed regardless of whether tetralin, benzene, or n-dodecane was used as the solvent.
  • Yuuki Mochizuki, Katsuyasu Sugawara
    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 233 2007年03月 [査読有り]
  • Yuuki Mochizuki, Katsuyasu Sugawara, Takuo Sugawara
    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 232 2006年09月 [査読有り]

MISC

  • Regeneration of Spent Denitration Catalyst of Coal Fired Power Plant
    Takahiro Kato, Kosuke Sakusabe, Yuuki Mochizuki, Hirokazu Okawa, Katsuyasu Sugawara Abstract of ACS Fall 2019 National Meeting & Exposition 2019年
  • Evolution of Mercury during Iron Ore Sintering
    Javzandolgor Bud, Yuuki Mochizuki, Naoto Tsubouchi Abstracts of the 18th Asian Pacific Confederation of Chemical Engineering Congress APCChE2019 Web 2019年 [査読無し][通常論文]
  • Adsorptive Removal of Organic Sulfur from Hydrocarbon Liquid Model Fuel by Ni-Loaded Carbon Prepared from Lignite
    Yuuki Mochizuki, Junpei Watanabe, Naoto Tsubouchi Abstracts of the 18th Asian Pacific Confederation of Chemical Engineering Congress APCChE2019 Web 2019年 [査読無し][通常論文]
  • Release Behavior of Mercury during Iron Ore Sintering Process (Division of Environmental Chemistry)
    Naoto Tsubouchi, Javzandolgor Bud, Yuuki Mochizuki Abstracts of Papers of the American Chemical Society 258 2019年 [査読有り][通常論文]
  • Dynamic Behavior of Mercury Release during Coal Carbonization and Iron Ore Sintering (Division of Environmental Chemistry)
    Naoto Tsubouchi, Javzandolgor Bud, Yuuki Mochizuki Abstracts of Papers of the American Chemical Society 257 2019年 [査読有り][通常論文]
  • Removal of Dibenzothiophene in a Liquid Hydrocarbon Fuel by Ni-Loaded Carbon Prepared from Lignite
    Yuuki Mochizuki, Junpei Watanabe, Naoto Tsubouchi Proceedings of the 14th Japan-China Symposium on Coal and C1 Chemistry USB 2018年 [査読無し][通常論文]
  • Preparation of Pelletized Coke by Co-Carbonization of Caking Coal and Pyrolyzed Char Modified with Tar Generated during Pyrolysis of Woody Biomass
    Yuuki Mochizuki, Naoto Tsubouchi Proceedings of the 14th Japan-China Symposium on Coal and C1 Chemistry USB 2018年 [査読無し][通常論文]
  • Production of High-Surface-Area Activated Carbon from Peat by Chemical Activation with Natural Soda Ash
    Javzandolgor Bud, Megumi Nishio, Yuji Shinohara, Yuuki Mochizuki, Naoto Tsubouchi Proceedings of the 14th Japan-China Symposium on Coal and C1 Chemistry USB 2018年 [査読無し][通常論文]
  • Production of High-Strength Cokes from Low-Quality Coals Chemically-Loaded with Thermoplastic Components
    Naoto Tsubouchi, Ryo Naganuma, Yuuki Mochizuki, Hideyuki Hayashizaki, Takahiro Shishido Proceedings of the 14th Japan-China Symposium on Coal and C1 Chemistry USB 2018年 [査読無し][通常論文]
  • Removal of Hydrogen Chloride Gas Using Natural Soda Ash
    Naoto Tsubouchi, Natsumi Matsuoka, Yuuki Mochizuki Proceedings of the 14th Japan-China Symposium on Coal and C1 Chemistry USB 2018年 [査読無し][通常論文]
  • Mercury Release during Coal Carbonization and Iron Ore Sintering
    Javzandolgor Bud, Yuuki Mochizuki, Naoto Tsubouchi Proceedings of the 2nd Australia-Japan Symposium on Carbon Resource Utilization USB 2018年 [査読無し][通常論文]
  • Fate of the Chlorine in Coal in the Temperature-Programmed Pyrolysis of Twenty Nine Coals
    Naoto Tsubouchi, Yuuki Mochizuki, Yanhui Wang, Yasuo Ohtsuka Proceedings of the 22nd International Symposium on Analytical and Applied Pyrolysis USB 2018年 [査読無し][通常論文]
  • タール由来炭素質物質による低品位コークスおよび熱分解チャーの高強度化
    望月友貴, 坪内直人, 窪田征弘, 上坊和弥 日本学術振興会石炭・炭素資源利用技術委員会研究会資料 163 61 -66 2018年 [査読無し][招待有り]
  • MA Jun, 望月友貴, 坪内直人, 秋山友宏 材料とプロセス(CD-ROM) 30 (2) ROMBUNNO.PS‐14 2017年08月21日 [査読無し][通常論文]
  • Release and Retention of the Chlorine in Coal during Pyrolysis and Gasification Processes
    Javzandolgor Bud, Yuuki Mochizuki, Naoto Tsubouchi Proceedings of the 17th Asian Pacific Confederation of Chemical Engineering Congress USB 2017年 [査読無し][通常論文]
  • Preparation of High-Strength Carbon/Carbon Composites from Tarry Materials and Low-Grade Cokes or Pyrolyzed Chars
    Jun Ma, Yuuki Mochizuki, Naoto Tsubouchi, Kazuya Uebo Proceedings of the 1st International Conference on Energy and Material Efficiency and CO2 Reduction in the Steel Industry USB 2017年 [査読無し][通常論文]
  • Fluorine Release and Retention during Fixed Bed Combustion of Pyrolyzed Coal Chars (Division of Energy & Fuels)
    Naoto Tsubouchi, Yuuki Mochizuki, Naoyuki Iwabuchi, Yuuki Akama, Yasuo Ohtsuka Abstracts of Papers of the American Chemical Society 252 2016年 [査読有り][通常論文]
  • 研究グループ紹介「北海道大学大学院工学研究院エネルギー変換システム設計研究室」
    坪内直人, 望月友貴 日本エネルギー学会誌 95 (3) 252 -254 2016年 [査読無し][招待有り]
  • Production of High-Strength Carbon-Loaded Iron Ores from Tar and Limonite to Solve Energy, Resource and Environmental Problems in Commercial Ironmaking Processes
    Jun Ma, Yuuki Mochizuki, Naoto Tsubouchi Proceedings of 2016 Annual Conference on Engineering and Applied Science USB 2016年 [査読無し][通常論文]
  • Reduction Rate and Crushing Strength of Composites Prepared from Cold-Bonded-Pellet and COG Tar
    Yusuke Mikawa, Yuuki Mochizuki, Naoto Tsubouchi Proceedings of the 4th Frontier Chemistry Center International Symposium – Future Dreams in Chemical Science and Technology: Bridges to Global Innovations 4 (4) 54 2016年 [査読無し][通常論文]
  • Effect of Inherent Oxygen Species on the Fluidity of Coal during Carbonization
    Ryo Naganuma, Yuuki Mochizuki, Naoto Tsubouchi Proceedings of the 4th Frontier Chemistry Center International Symposium – Future Dreams in Chemical Science and Technology: Bridges to Global Innovations 4 (4) 55 2016年 [査読無し][通常論文]
  • 研究活動総覧「北海道大学大学院工学研究院エネルギー変換システム設計研究室」
    坪内直人, 熊谷治夫, 望月友貴 触媒技術の動向と展望 2015年 [査読無し][招待有り]
  • Utilization of Low-Valued Iron Ores as High Performance Materials to Develop a Novel Hot Gas Cleanup Method for an Integrated Gasification Combined Cycle
    Naoto Tsubouchi, Ayumu Ogawa, Yuuki Mochizuki Proceedings of World Engineering Conference and Convention 2015 131 2015年 [査読無し][通常論文]
  • Influence of Oxygen Element on Coal Fluidity
    Ryo Naganuma, Kyohei Kamiya, Yuuki Mochizuki, Kazuya Uebo, Naoto Tsubouchi Proceedings of International Conference on Coal Science and Technology 2015 USB 2015年 [査読無し][通常論文]
  • Reduction Behavior and Crushing Strength of Carbon-Containing Composites Prepared from COG Tar and Cold Bonded Pellets
    Yuuki Mochizuki, Naoto Tsubouchi, Tomohiro Akiyama Proceedings of the 13th China-Japan Symposium on Coal and C1 Chemistry USB 2015年 [査読無し][通常論文]
  • Evolution of Hydrogen Fluoride during Coal Pyrolysis and Subsequent Char Combustion (Division of Energy & Fuels)
    Naoto Tsubouchi, Yuuki Mochizuki, Naoyuki Iwabuchi, Yuuki Akama, Yasuo Ohtsuka Abstracts of Papers of the American Chemical Society 250 2015年 [査読有り][通常論文]
  • Fluorine Release and Retention during Coal Pyrolysis and Subsequent Char Combustion
    Naoto Tsubouchi, Yuuki Mochizuki Proceedings of the 10th European Conference on Coal Research and Its Applications CD-ROM 2014年 [査読無し][通常論文]
  • Effect of Indole Addition on Coke Strength
    Naoto Sakimoto, Toshimasa Takanohashi, Yasuyuki Harada, Hidekazu Fujimoto, Yuuki Mochizuki, Naoto Tsubouchi Proceedings of the 4th International Symposium on Gasification and its Applications USB 2014年 [査読無し][通常論文]
  • Decomposition of Ammonia and Pyridine with an Inexpensive Limonite Catalyst
    Yuuki Mochizuki, Ayumu Ogawa, Naoto Tsubouchi Proceedings of the 4th International Symposium on Gasification and its Applications USB 2014年 [査読無し][通常論文]
  • 安田尚人, 能村貴宏, CAHYONO Rochim B, 望月友貴, 坪内直人, 秋山友宏 化学工学会年会研究発表講演要旨集(CD-ROM) 78th ROMBUNNO.P124 2013年02月17日 [査読無し][通常論文]
  • Ultimately-Efficient Utilization of Fossil Fuels as the Best Way to Reduce CO2 Emissions
    Naoto Tsubouchi, Haruo Kumagai, Yuuki Mochizuki Proceedings of the 1st Frontier Chemistry Center International Symposium – Next Generation of Molecular Chemistry 1 (1) 33 2013年 [査読無し][通常論文]
  • Sulfur Distribution during Coal Carbonization and Influence of Addition of S-Containing Compounds on Gieseler Fluidity
    Yuuki Mochizuki, Yohei Ono, Kazuya Uebo, Naoto Tsubouchi Proceedings of the 12th Japan-China Symposium on Coal and C1 Chemistry USB 2013年 [査読無し][通常論文]
  • Catalytic Performance of Limonite in the Decomposition of Pyridine at High Temperatures
    Ayumu Ogawa, Yuuki Mochizuki, Naoto Tsubouchi Proceedings of International Conference on Coal Science and Technology 2013 CD-ROM 2013年 [査読無し][通常論文]
  • Catalytic Decomposition of Pyridine with Iron Nanoparticles Produced from Limonite
    Yuuki Mochizuki, Ayumu Ogawa, Haruo Kumagai, Naoto Tsubouchi Proceedings of the 9th World Congress of Chemical Engineering incorporating with the 15th Asian Pacific Confederation of Chemical Engineering Congress USB 2013年 [査読無し][通常論文]

書籍等出版物

共同研究・競争的資金等の研究課題

  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2021年04月 -2024年03月 
    代表者 : 望月 友貴
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2021年07月 -2023年03月 
    代表者 : 望月 友貴
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2017年04月 -2019年03月 
    代表者 : 望月 友貴
     
    劣質炭素資源のアップグレーディング法の開発のため、木質バイオマスから調製した熱分解チャーの細孔内に同じく熱分解で生成したタールを含浸ならびに気相蒸着法による担持させた炭素/炭素複合体を調製し、そのコークス化特性を調べた。その結果、いずれの手法においてもチャー細孔内にタール由来炭素質物質を充填でき、元の熱分解チャー収率を大きく上回る複合体を調製可能であった。原料炭に複合体を配合して調製したコークスの強度を調べたところ、本複合体は微粘結炭の代替や粘結炭の使用量の低減させることができるコークス原料になり得る可能性が示された。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2014年04月 -2017年03月 
    代表者 : 坪内 直人, 望月 友貴
     
    炭素系資源の加熱時に発生するHClの二次的反応を理解するため、フェノール樹脂由来の純炭素をO2賦活後、K、Ca、CuおよびZnをドープしたモデル炭素質物質を100 ppm HCl/N2中500℃で保持した。その結果、炭素は金属の有無に依らずHClと容易に反応し、その量は金属無しでは炭素活性サイトの増加で増大し、また、Ca、Cu、Zn存在下で大きくなった。さらに、これらの金属種共存下では、炭素単独に比べ、塩素化芳香族のXPSピークの強度が増大した。以上より、高温プロセス由来の有機塩素化合物は、HCl、炭素質物質(未燃炭素等)、金属種(Ca、Cu、Zn等)が関与する反応で生成することが見出された。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2010年 -2012年 
    代表者 : 菅原 勝康, 望月 友貴
     
    本研究は、光学ガラスの製造工程で生じる研磨粉や切断片に含まれる希少元素を効率的に分離回収するためのプロセス開発を目的とした。研磨紛ならびに切断片を塩素気流中、200℃から1000℃で加熱したときの希少元素(La やGa, Nb, Ta)ならびに共存元素(Ti, Zr, Zn)の塩化揮発挙動を詳細に追跡した。この実験結果をもとに、光学ガラス試料に炭素を添加し塩素気流中で500、700、1000℃と三段階に分けて加熱することにより、La やTa, Nb, Gd を選択的に分離回収するプロセスを開発した。

産業財産権

  • US 8,920,535:Method of Separating and Recovering Metal Elements  2014年12月30日
    M.Kiyosawa, K.Nochi, N.Kobayashi, K.Iida, K.Sugawara, Y.Mochizuki
  • 特許6414903:炭素内装鉱の製造方法  
    村井亮太, 石渡夏生, 殿村重彰, 菊池直樹, 富田幸雄, 富崎真, 秋山友宏, 坪内直人, 望月友貴
  • 特許6070462:被処理ガス中の有機窒素化合物の分解方法  
    上坊和弥, 坪内直人, 望月友貴, 小川歩
  • 特開2012-41588:塩化揮発法による希土類元素の分離方法及び分離システム  
    菅原勝康，望月友貴，森広介

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