Passive thermal management of CO2 Methanation using phase change material with high thermal conductivity
Hiroaki Koide, Akira Gunji, Masatoshi Sugimasa, Takahiro Kawaguchi, Cholila Tamzysi, Takahiro Nomura
Applied Energy, 380, 124942, 124942, Elsevier BV, Feb. 2025
Scientific journal

Microencapsulation of Zn-10 mass% Al alloy phase change material via dry synthesis method
Takahiro Kawaguchi, Tomokazu Nakamura, Minako Kondo, Joshua Chidiebere Mba, Kaixin Dong, Yuto Shimizu, Melbert Jeem, Takahiro Nomura
Chemical Engineering Journal, 154782, 154782, Elsevier BV, Aug. 2024
Scientific journal

Large supercooling of Al Si alloy in microcapsule composed of Al2O3 shell
Hiroki Sakai, Takahiro Kawaguchi, Yuto Shimizu, Takahiro Nomura
Journal of Energy Storage, 87, 111261, 111261, Elsevier BV, May 2024
Scientific journal

Shell-Driven Localized Oxide Nanoparticles Determine the Thermal Stability of Microencapsulated Phase Change Material
Melbert Jeem, Ryosuke Ishida, Minako Kondo, Yuto Shimizu, Takahiro Kawaguchi, Kaixin Dong, Ade Kurniawan, Yuji Kunisada, Norihito Sakaguchi, Takahiro Nomura
ACS Applied Materials & Interfaces, 16, 3, 3509, 3519, American Chemical Society (ACS), 16 Jan. 2024
Scientific journal

High-temperature ternary Cu–Si–Al alloy as a core–shell microencapsulated phase change material: fabrication via dry synthesis method and its thermal stability mechanism
Masahiro Aoki, Melbert Jeem, Yuto Shimizu, Takahiro Kawaguchi, Minako Kondo, Tomokazu Nakamura, Chihiro Fushimi, Takahiro Nomura
Materials Advances, Royal Society of Chemistry (RSC), 2024
Scientific journal, Development of Cu–12.8Si–20Al/Al₂O₃ core–shell micro-encapsulated phase change materials (MEPCMs) via a dry synthesis mechanical impact technique.

Novel microencapsulated ternary eutectic alloy-based phase change material
Yuto Shimizu, Shunsuke Cho, Takahiro Kawaguchi, Keita Tanahashi, Kaixin Dong, Tomokazu Nakamura, Ade Kurniawan, Melbert Jeem, Takahiro Nomura
Journal of Energy Storage, 75, 109535, 109535, Elsevier BV, Jan. 2024
Scientific journal

Composite phase change material based on Al alloy with durability of over 10,000 cycles for high-temperature heat utilization
Takahiro Kawaguchi, Melbert Jeem, Ade Kurniawan, Kaixin Dong, Minako Kondo, Yusuke Sato, Tomokazu Nakamura, Takahiro Nomura
Journal of Energy Storage, 75, 109635, 109635, Elsevier BV, Jan. 2024
Scientific journal

Latent heat storage composites composed of Al-Si microencapsulated phase change material and alumina matrix
Takahiro Kawaguchi, Yuto Shimizu, Kaixin Dong, Ade Kurniawan, Takahiro Nomura
ENERGY STORAGE, WILEY, Jun. 2023
English, Scientific journal, Latent heat storage (LHS) using phase change materials (PCMs) is expected for application to heat utilization at high-temperature because it can provide a heat source of high density and constant temperature. Even among PCMs, metals/alloys are promising for high-temperature operation. However, metals and alloys PCM are concerned about corrosion reactions with structural materials. As a result, micro-encapsulated PCMs (MEPCMs) have been created in which the surface of alloy PCM is encased in a stable oxide coating. Since the surface of MEPCM is an oxide, the creation of structures with the function of LHS in a variety of shapes by combining MEPCM with sintering aids is also possible. In this study, composite PCMs were prepared by combining Al-25 mass% Si MEPCM with fine alpha-Al2O3 particles as a sintering aid. Consequently, PCM composites containing 70-90 vol.% of the MEPCM and heat-treated at 1200 degrees C or 1300 degrees C were successfully fabricated. In particular, a high heat storage density of 0.47 GJ m(-3) was obtained under conditions containing 90 vol.% of the MEPCM and a heat treatment temperature of 1200 degrees C, which is 1.6-fold higher than that of existing sensible heat storage materials. Additionally, the composite PCM retained its shape and the latent heat capacity even after 300 cycles of cyclic testing. Thus, the high heat storage density and high durability of the composite PCM are expected to further promote the expansion of high-temperature heat utilization in future studies.

Ironmaking Using Municipal Solid Waste (MSW) as Reducing Agent: A Preliminary Investigation on MSW Decomposition and Ore Reduction Behavior
Hiroki Hasegawa, Ade Kurniawan, Itsuki Iwamoto, Rochim Bakti Cahyono, Arief Budiman, Yoshiaki Kashiwaya, Takahiro Nomura
ISIJ International, 62, 12, 2491, 2499, Iron and Steel Institute of Japan, 15 Dec. 2022
Scientific journal

Oxygen Separation Performance of Ca₂AlMnO_5+<i>δ</i> as an Oxygen Storage Material for High-Temperature Pressure Swing Adsorption
Keita Tanahashi, Yusei Omura, Hidekazu Naya, Yuji Kunisada, Norihito Sakaguchi, Ade Kurniawan, Takahiro Nomura
ISIJ International, 62, 12, 2578, 2586, Iron and Steel Institute of Japan, 15 Dec. 2022
Scientific journal

Development of core-shell type microencapsulated phase change material with Zn-30 mass% Al alloy and its shell formation mechanism
Takahiro Kawaguchi, Hiroki Sakai, Ryosuke Ishida, Yuto Shimizu, Ade Kurniawan, Takahiro Nomura
JOURNAL OF ENERGY STORAGE, 55, ELSEVIER, Nov. 2022
English, Scientific journal, Latent heat storage (LHS) technology is promising because it can store and release heat at a constant temperature utilizing phase change material (PCM) and is a superior alternative for sensible heat storage (SHS) technology. In this study, we report an improved preparation method for microencapsulated PCM (MEPCM) with Zn-30 mass% Al (melting temperature: 440-512 degrees C) as the PCM. Conventional MEPCM preparation involves boehmite treatment for 3 h in boiling water to form AlOOH shells on Zn-30 mass% Al alloy particles (average diameter: 35.7 mu m) and heat-oxidation treatment to form an oxide shell in oxygen atmosphere at 800. C. In this study, Al(OH)(3) is added to the treatment solution before boehmite treatment; furthermore, precipitation treatment at 75 degrees C for 16 h is investigated. After heat-oxidation treatment, different Al and Zn oxide shells are formed on the surface of the alloy particles depending on the Al(OH)(3) quantity added before boehmite treatment and precipitation treatment. The prepared MEPCM has a heat storage density of 0.48 GJ m (3) and excellent cyclic durability of >100 melting and solidification cycles. In addition to this, investigations related to the fabrication of composite PCM by mixing it with a glass frit was carried out for improving the durability of the MEPCM. Therefore, this material can be utilized in future medium-to-high temperature heat applications such as transportation, chemical processes, and renewable energy.

Al-Ni alloy-based core-shell type microencapsulated phase change material for high temperature thermal energy utilization
Yuto Shimizu, Takahiro Kawaguchi, Hiroki Sakai, Kaixin Dong, Ade Kurniawan, Takahiro Nomura
SOLAR ENERGY MATERIALS AND SOLAR CELLS, 246, ELSEVIER, Oct. 2022
English, Scientific journal, Latent heat thermal energy storage (LHTES) using alloy-based phase-change materials (PCMs) is a promising technique for stabilizing the power supply of grid-connected renewable energies. In particular, recently devel-oped alloy-based microencapsulated PCMs (MEPCMs) are attracting considerable attention owing to their ease of handling and ability to overcome the problems of corrosion and melting leakage experienced by alloy PCMs. To expand high-temperature LHTES, more MEPCMs need to be developed. In this study, an MEPCM was developed using Al-5 wt.%Ni alloy (melting point 640C). Microencapsulation was performed in two steps: 1) Al hydroxide layer formation on the surface of PCM particles by boehmite treatment in boiling water for 1 h or 3 h and 2) Al2O3 shell formation by heat oxidation treatment in an O2 atmosphere. The prepared MEPCM consisted of an alpha-Al2O3 shell and an Al-Ni alloy core. The sample after 1 h of boehmite treatment and heat oxidation treatment had melting and solidification latent heat capacities of 241 J g(-1) and 251 J g(-1), respectively. The developed MEPCM maintained its original shape and high latent heat capacity, even after 100 cycles of melting and solidification. The developed Al-Ni alloy-based MEPCM is expected to be applied to next-generation LHTES, in which a large-scale and ultrafast heat exchange system is employed in a small space by cascade configuration with other MEPCMs with different melting points. In addition, the formation of the Al-Ni alloy core/alpha-Al2O3 shell structure was investigated thermodynamically, providing insights that will promote the development of Al -X alloy-based MEPCMs in the future.

Functional surface modification of Al-Si@Al2O3 microencapsulated phase change material
Daisuke Ajito, Ade Kurniawan, Yuto Shimizu, Ryosuke Ishida, Takahiro Kawaguchi, Kaixin Dong, Hiroki Sakai, Takahiro Nomura
JOURNAL OF ENERGY STORAGE, 52, ELSEVIER, Aug. 2022
English, Scientific journal, Core-shell structured Al-Si@Al2O3 microencapsulated phase change material (MEPCM) has shown promise for high-temperature latent heat thermal energy storage applications, and has recently been proposed as a thermoregulating catalyst support. However, the reported performances of MEPCMs are lower than those of conventional catalyst supports, owing to low specific surface areas of the former. MEPCMs were originally prepared in two steps: boehmite treatment and thermal oxidation treatment. This study was aimed at modifying the MEPCM shell surface morphology to increase its specific surface area by introducing additives and adjusting the pH of solutions during boehmite treatment. Al-25 wt% Si alloy powder as raw material was hot-stirred in distilled water at 100 degrees C, for 3 h to form AlOOH layers, the Al2O3 shell-precursors, on the surface of Al-Si particles. Different metal-nitrate solutions (metal: La, Ni, Zn, Fe, Ca, Mg) were added during boehmite treatment to control the particle surface precipitate. The boehmite-treated samples were filtered, dried, and heat-oxidized in air at 1000 degrees C for 3 h to form the Al2O3-shell-MEPCMs. Interestingly, upon addition of metal-nitrate solutions during boehmite treatment, a significant amount of AlOOH or Al(OH)(3) crystal-grains were formed. The MEPCM sample prepared using La nitrate solution exhibited remarkably high specific surface area of 40.9 m(2) g(-1), in contrast to the sample formed without any additive (2.4 m(2) g(-1)), indicating higher suitability as a catalyst support. Thus, the MEPCM shell surface morphology could be easily controlled to increase surface area and facilitate catalyst-support activity.

Barium Indate-Zirconate Perovskite Oxyhydride with Enhanced Hydride Ion/Electron Mixed Conductivity
Hajime Toriumi, Genki Kobayashi, Takashi Saito, Takashi Kamiyama, Takaaki Sakai, Takahiro Nomura, Sho Kitano, Hiroki Habazaki, Yoshitaka Aoki
CHEMISTRY OF MATERIALS, 34, 16, 7389, 7401, AMER CHEMICAL SOC, Aug. 2022
English, Scientific journal, Oxyhydrides have excellent potential as electrochemical and catalytic materials owing to the synergistic effects of the conductivity and redox activity of the hydride (H-) ion. However, harsh preparation conditions and their pyrolytic nature limit their applications. Herein, we discover highly durable oxyhydride perovskite BaZr0.5In(II)(0.5)O2.25H0.5 with enhanced H- ion-electron mixed conductivity. BaZr0.5In-(III)O-2.75, as the parent phase, was reductively hydrogenated to BaZr(0.5I)n(II)(0.5)O2.25H0.5 as via simple H-2 gas annealing at 800 degrees C under an ambient pressure with the incorporation of H- ions with simultaneous oxygen vacancy formation. Membrane devices comprising dense BaZr0.5In0.5O2.25H0.5 films on porous Ni-cermet supports were fabricated by conventional sintering and postreduction because low lattice contraction (-0.07%) following hydrogenation allowed for the bulk hydrogenation of BaZr0.5In0.5O2.75 sinters without structural collapse. The resulting devices exhibited higher hydrogen permeability than protonic ceramic ones at 500 degrees C because BaZr0.5In(II)(0.5)O2.25H0.5, allows H- ion hopping between the nearest-neighbor anion sites due to the significantly high oxygen deficiency (25% of O sites are vacant), giving rise to a H- ion conductivity of 10(-3) S cm(-1). Given their superior H- ion conductivity and ease of manufacturing, the synthesized materials have great potential for applications in mixed conducting electrodes and hydrogen-permeable membrane supports of ceramic electrochemical cells.

Modified preparation of Al2O3@Al microencapsulated phase change material with high durability for high-temperature thermal energy storage over 650 degrees C
Takahiro Kawaguchi, Julalak Yoolerd, Hiroki Sakai, Yuto Shimizu, Ade Kurniawan, Takahiro Nomura
SOLAR ENERGY MATERIALS AND SOLAR CELLS, 237, ELSEVIER, Apr. 2022
English, Scientific journal, Latent heat storage using phase change materials (PCMs) with high melting points above 600 degrees C can mitigate the fluctuation in renewable energy supply and recover energy from industrial waste heat. Microencapsulated PCMs (MEPCMs) expand the possibilities of heat utilization owing to the presence of a thermally and chemically stable coating on the PCMs. This study improves the durability of an Al-based MEPCM (melting point: 660 degrees C) with an Al2O3 coating. The conventional process for preparing Al-based MEPCMs, which involves a boehmite treatment in boiling water and a heat-oxidation treatment at high temperature, was modified by adding Al(OH)(3) before the boehmite treatment to precipitate Al(OH)(3) on the surfaces of the Al particles after the boehmite treatment. The precipitation treatment increased the thickness of the oxide coating, thereby enabling the proposed Al-based MEPCM to withstand 300 melting and solidification cycles. In addition, the Al-based MEPCM reported an excellent heat storage capacity of 186 J g(-1). This Al-based MEPCM with excellent durability and high heat storage capacity may be further developed for use in future thermal energy storage and management systems.

Developing Composite Phase Change Material with Al-Si Base Microencapsulated Phase Change Material and Glass Frit for High Temperature Applications
Takahiro Kawaguchi, Hiroki Sakai, Yuto Shimizu, Kaixin Dong, Ade Kurniawan, Takahiro Nomura
ISIJ INTERNATIONAL, 62, 12, 2567, 2572, IRON STEEL INST JAPAN KEIDANREN KAIKAN, 2022
English, Scientific journal, To achieve high energy efficiency and CO2 reduction during iron- and steelmaking, thermal management is vital. Use of phase change material (PCMs) to store excess energy in the form of latent heat has the potential to realize excellent thermal management. Microencapsulated PCMs (MEPCMs) consisting of an alloy PCM core and an oxide coating have improved corrosion resistance and are easy to mix with other materials. Conventionally, composite PCM pellets are fabricated by mixing glass frit (to aid sintering) with Al-25 mass% Si MEPCM. However, this process has not yet been optimized. In this study, the optimal stoichiometry of composite PCMs prepared using Al-25 mass% Si MEPCM and glass frit was investigated. The pellets were prepared by mixing with glass frit at 60, 80 and 90 mass% of MEPCM, followed by molding and heat treatment. As a result, pellets were successfully fabricated with condition including 60 and 80 mass% of MEPCM. The latent heat capacity of the composite PCM was 146 J g(-1), which was at least 1.59 times higher than that of existing sensible heat storage (SHS) materials. Moreover, the composite PCMs withstood 300 melting and solidification cycles. In summary, composite PCMs with excellent latent heat capacity and durability were successfully prepared.

Performance analysis of packed bed latent heat storage system for high-temperature thermal energy storage using pellets composed of micro-encapsulated phase change material
Hiroaki Koide, Ade Kurniawan, Tatsuya Takahashi, Takahiro Kawaguchi, Hiroki Sakai, Yusuke Sato, Justin NW. Chiu, Takahiro Nomura
ENERGY, 238, PERGAMON-ELSEVIER SCIENCE LTD, Jan. 2022
English, Scientific journal, High temperature latent heat storage has gained increasing attention owing to its potential in the integration of renewable energy sources. This study is a novel experimental investigation on the heat storage performance of a horizontal packed bed containing composites comprising Al-Si-based microencapsulated phase change material in a high-temperature air heating system. The pellet type composites with 3 mm is tested here in a 1L scale packed bed heat exchanger at airflow rates between 75 and 150 L min(-1). The composite exhibited a narrow phase change temperature range and high heat storage/ release characteristics. As the airflow increased, the phase change time of the composite decreased, and the heat exchanging rate increased. The heat exchange efficiency during charging and discharging ranged from 71.0 % to 98.3 % and 69.0 %-90.2 %, respectively. In the discharging mode, although supercooling which comes from the microencapsulated phase change material, was observed, this did not noticeable effect on the heat transfer. (C) 2021 Published by Elsevier Ltd.

Sr-Doped Ca2AlMnO5 + δ for Energy-Saving Oxygen Separation Process
Keita Tanahashi, Yusei Omura, Hidekazu Naya, Kaho Miyazaki, Genki Saito, Yuji Kunisada, Norihito Sakaguchi, Takahiro Nomura
ACS Sustainable Chemistry & Engineering, 9, 28, 9317, 9326, American Chemical Society (ACS), 19 Jul. 2021
Scientific journal

Catalyst-loaded micro-encapsulated phase change material for thermal control of exothermic reaction
Tatsuya Takahashi, Hiroaki Koide, Hiroki Sakai, Daisuke Ajito, Ade Kurniawan, Yuji Kunisada, Takahiro Nomura
Scientific Reports, 11, 1, 7539, Springer Science and Business Media LLC, Apr. 2021, [Peer-reviewed], [Last author, Corresponding author], [International Magazine]
English, Scientific journal, CO₂ methanation is a promising technology to enable the use of CO₂ as a resource. Thermal control of CO₂ methanation, which is a highly active exothermic reaction, is important to avoid thermal runaway and subsequent degradation of the catalyst. Using the heat storage capacity of a phase change material (PCM) for thermal control of the reaction is a novel passive approach. In this study a novel structure was developed, wherein catalysts were directly loaded onto a micro-encapsulated PCM (MEPCM). The MEPCM was prepared in three steps consisting of a boehmite treatment, precipitation treatment, and heat oxidation treatment, and an impregnation process was adopted to prepare a Ni catalyst. The catalyst-loaded MEPCM did not show any breakage or deformation of the capsule or a decrease in the heat storage capacity after the impregnation treatment. MEPCM demonstrated a higher potential as an alternative catalyst support in CO₂ methanation than the commercially available α-Al₂O₃ particle. In addition, the heat storage capacity of the catalyst-loaded MEPCM suppressed the temperature rise of the catalyst bed at a high heat absorption rate (2.5 MW m⁻³). In conclusion, the catalyst-loaded MEPCM is a high-speed, high-precision thermal control device because of its high-density energy storage and resolution of a spatial gap between the catalyst and cooling devices. This novel concept has the potential to overcome the technical challenges faced by efficiency enhancement of industrial chemical reactions.

High Anisotropic Thermal Conductivity, Long Durability Form-Stable Phase Change Composite Enhanced by a Carbon Fiber Network Structure
Kaixin Dong, Nan Sheng, Deqiu Zou, Cheng Wang, Xuemei Yi, Takahiro Nomura
Crystals, 11, 3, 230, 230, MDPI AG, 25 Feb. 2021, [Peer-reviewed], [Last author, Corresponding author], ［Internationally co-authored］, [International Magazine]
English, Scientific journal, To address the drawback of low thermal conductivity of conventional organic phase change materials (PCMs), a paraffin-wax-based phase change composite (PCC) was assembled via a vacuum impregnation method, using a new type of carbon fiber network material as the supporting matrix. The carbon fiber sheet (CFS) material exhibited a network structure comprising high-thermal-conductivity carbon fibers, beneficial for enhancing the heat transfer properties of the PCC. The sheet-shaped carbon fiber material was stacked and compressed, and then impregnated with the liquid paraffin wax PCM to form the composite. The thermal conductivity, durability, shape stability, chemical stability, and heat storage characteristics of the PCC specimen were carefully analyzed. The maximum thermal conductivity of the PCC was 11.68 W·m−1·K−1 (4670% compared to that of pure paraffin) in the radial direction, and 0.93 W·m−1·K−1 in the axial direction of the sample, with 17.44 vol % of added CFS. The thermal conductivity retention rate after 200 thermal cycles was 78.6%. The PCC also displayed good stability in terms of chemical structure, shape, and heat storage ability. This study offers insights and a possible strategy for the development of anisotropic high-thermal-conductivity PCCs for potential applications in latent heat storage systems.

Faster Generation of Nanoporous Hematite Ore through Dehydration of Goethite under Vacuum Conditions
Ade Kurniawan, Genki Saito, Takahiro Nomura, Tomohiro Akiyama
ISIJ International, 61, 1, 493, 497, Iron and Steel Institute of Japan, 15 Jan. 2021, [Peer-reviewed], [Domestic magazines]
English, Scientific journal

Rapid oxygen storage and release with Brownmillerite-structured Ca2AlMnO5
Ayumu Sato, Genki Saito, Keisuke Abe, Yuji Kunisada, Norihito Sakaguchi, Tomohiro Akiyama, Takahiro Nomura
Journal of Alloys and Compounds, 851, 156817, 156817, Elsevier BV, Jan. 2021, [Peer-reviewed], [Last author, Corresponding author], [International Magazine]
English, Scientific journal

Kinetic Analysis Considering Particle Size Distribution on Ca Elution from Slags in CaO–SiO₂–MgO–Al₂O₃–Fe₂O₃ System
Yoshiaki Kashiwaya, Seitarou Tauchi, Takanori Nomura, Tomohiro Akiyama
ISIJ International, 60, 12, 2859, 2869, Iron and Steel Institute of Japan, 15 Dec. 2020, [Peer-reviewed], [Domestic magazines]
English, Scientific journal

Fabrication of Heat Storage Pellets Consisting of a Metallic Latent Heat Storage Microcapsule and an Al₂O₃ Matrix
Hiroki Sakai, Ade Kurniawan, Tomohiro Akiyama, Takahiro Nomura
ISIJ International, 60, 10, 2152, 2156, Iron and Steel Institute of Japan, 15 Oct. 2020, [Peer-reviewed], [Last author, Corresponding author], [Domestic magazines]
English, Scientific journal

Microencapsulation of Zn-Al alloy as a new phase change material for middle-high-temperature thermal energy storage applications
Takahiro Kawaguchi, Hiroki Sakai, Nan Sheng, Ade Kurniawan, Takahiro Nomura
Applied Energy, 276, 115487, Elsevier BV, Oct. 2020, [Peer-reviewed], [Last author, Corresponding author], [International Magazine]
English, Scientific journal, Thermal energy storage (TES) that utilizes renewable energy and industrial waste heat has recently attracted attention. For the development of TES technology, latent heat storage (LHS) technology using phase change materials (PCMs) is necessary. Covering a PCM with a thermally and chemically stable shell to form a microencapsulated PCM (MEPCM) expands applicability. In this study, for the first time, the authors report the microencapsulation of Zn-30 wt%Al alloy, a new PCM for middle-high temperature (400-500 degrees C) applications. The microencapsulation process was conducted in two main steps, viz. formation of an AlOOH-based shell on the PCM particles by boehmite treatment and heat-oxidation treatment in an O-2 atmosphere to form an oxide shell. Furthermore, composites were synthesized by sintering the MEPCMs with glass frit (GF) as the sintering agent. The prepared MEPCM had multilayers with 500 nm thickness of ZnO and 300 nm thickness of Al-oxide. It exhibited a phase-change temperature of 437-512 degrees C and latent heat of 117 J g(-1). About 75% of the MEPCM-particles retained their spherical shape after 100 melting and solidification cycles, in addition, the MEPCM-GF composite completely retained their shape and thermal energy storage performances after 100 melting and solidification cycles. Therefore, the authors believe that the MEPCMs and their composites described in this study have the potential to develop new applications involving thermal energy storage, transportation, and management.

Development of Novel Microencapsulated Hybrid Latent/Chemical Heat Storage Material
Hiroaki Koide, Tatsuya Takahashi, Hiroki Sakai, Ade Kurniawan, Justin Ning-Wei Chiu, Takahiro Nomura
ACS Sustainable Chemistry & Engineering, 8, 39, 14700, 14710, American Chemical Society (ACS), 07 Aug. 2020, [Peer-reviewed], [Last author, Corresponding author], ［Internationally co-authored］, [International Magazine]
English, Scientific journal, Phase change materials (PCM) and thermochemical materials (TCM) attract increasing attention as next-generation heat storage technologies. A novel CaO-supported microencapsulated phase change material (CaO/MEPCM) has been developed by combining a latent heat storage material with a chemical heat storage material. With this novel concept, higher storage performance and improved structural benefits are obtained. Microencapsulated Al-25 wt % Si alloy as the PCM and CaO/Ca(OH)(2) as the TCM are investigated in this paper. Sample preparation processes include (1) boehmite (AlOOH) treatment, (2) thermal oxidation treatment, (3) impregnation with CaO precursor, and (4) calcination. From SEM and XRD, the presence of CaO was confirmed on the microcapsules. According to the thermal analysis of CaO 30 wt %/MEPCM under a controlled H2O/N-2 atmosphere, two endothermic peaks are present at around 500 and 577 degrees C, and the total heat storage capacity amounts to 412 kJ kg(-1). Besides this, the stability in five cycles is also shown. It is also demonstrated through this work that the expansion of CaO can be successfully suppressed with the impregnation coating treatment. These results indicate that the combination of latent heat storage material and chemical heat storage material attains a synergistic effect and that the result is a novel heat storage material hybrid with high application potentials.

Reaction Heat Control for Steam Reforming of Ethanol with Ni-supported Latent Heat Storage Grain
Hiroki Sakai, Yuta Hasegawa, Ade Kurniawan, Takahiro Nomura, Tomohiro Akiyama
Tetsu-to-Hagane, 106, 8, 534, 541, Iron and Steel Institute of Japan, 31 Jul. 2020, [Peer-reviewed], [Corresponding author], [Domestic magazines]
Japanese, Scientific journal

Low-Temperature Synthesis of TiC from Carbon-Infiltrated, Nano-porous TiO2
Masafumi Sanada, Keisuke Abe, Ade Kurniawan, Takahiro Nomura, Tomohiro Akiyama
Metallurgical and Materials Transactions B, 51, 5, 1958, 1964, Springer Science and Business Media LLC, 06 Jul. 2020, [Peer-reviewed], [International Magazine]
English, Scientific journal

Ga‐based microencapsulated phase change material for low‐temperature thermal management applications
Kohei Kashiyama, Takahiro Kawaguchi, Kaixin Dong, Hiroki Sakai, Nan Sheng, Ade Kurniawan, Takahiro Nomura
Energy Storage, 2, 5, e177, Wiley, 19 May 2020, [Peer-reviewed], [Last author, Corresponding author], [International Magazine]
English, Scientific journal, Gallium is expected to use as a high-performance phase change material (PCM) for a low-temperature thermal management. However, high corrosivity of liquid gallium is a serious technical barrier to handle gallium as a PCM. To this end, we report on the development of a Ga-based microencapsulated PCM (MEPCM) by using a three-step process. First, Ga is particularized by high-speed mixing. Second, a GaOOH shell is precipitated on the surface of the Ga particles by chemical treatment. Finally, the GaOOH shell is subjected to an oxidation treatment, after which the shell transforms into a Ga2O3 shell. As the results, MEPCM obtained at the oxidation temperature of 600 degrees C was the only one completely covered with a shell without agglomeration. The MEPCM was composed of a beta -Ga2O3 shell and Ga core with internal voids, whose presence can relieve the pressure on the shell owing to the volume expansion of the core during solidification. The latent heat of the MEPCM was nearly 56% that of the Ga particles. This study demonstrates the first successful microencapsulation of Ga and exhibits the potential of Ga as a new thermal management material.

Fabrication of heat storage pellets composed of microencapsulated phase change material for high-temperature applications
Hiroki Sakai, Nan Sheng, Ade Kurniawan, Tomohiro Akiyama, Takahiro Nomura
Applied Energy, 265, 114673, Elsevier BV, May 2020, [Peer-reviewed], [Last author, Corresponding author], [International Magazine]
English, Scientific journal, Latent heat storage using a metallic phase change material (PCM) is an attractive option for high-temperature thermal energy storage. However, there are serious technical barriers to applying a metallic PCM to practical applications, mainly caused by its high corrosivity. This study reports the fabrication of a pellet-type PCM composite, mainly composed of a microencapsulated metallic PCM, as a potentially viable solution to this issue. This microencapsulated PCM (MEPCM) has a core composed of Al-25 mass% Si, which acts as a PCM. Its shell is composed of Al2O3 (or a precursor of Al2O3), and grass frit was used as a sinter agent. The composites were fabricated by mixing the MEPCM with a sintering agent, pelletizing, and sintering. The PCM composites exhibited a melting point of similar to 577 degrees C and a latent heat of 108-122 J g(-1). The thermal conductivities of the PCM composites were in the range of 2.16-3.20 W m(-1) K-1. The cycling performance demonstrated the good durability of the composites. There were no significant changes in the shape and chemical composition of the pellets, even after 300 cycles of melting and freezing tests. These results indicate that the concept of pellet-type composites using MEPCM developed in this study will overcome the technical barriers to utilizing metallic PCMs. Thermal energy storage structures in various shapes could be fabricated via the method for fabricating PCM composites proposed in this study. This concept therefore shows substantial promise for application in high-temperature thermal energy storage systems.

Kinetic Study of Simultaneous Ethanol Decomposition and Reduction of Low-grade Iron ore at Transient Temperature
A. Kurniawan, K. Abe, M. Sanada, T. Nomura, T. Akiyama
IOP Conference Series: Materials Science and Engineering, 778, 1, Institute of Physics Publishing, 30 Apr. 2020
English, International conference proceedings, An ethanol-assisted ironmaking method had previously been proposed, resulting in a significantly lower temperature of iron reduction. However, the kinetic mechanism remains unknown. A kinetic model for transient temperature condition was introduced, then numerically solved and curve-fitted to the experimental data using MATLAB software. There were 8 main reactions involved: (1) decomposition of ethanol, (2) decomposition of methane, (3) steam reforming of methane, (4) water-gas shift, (5) Boudoard reaction, (6) direct reduction by C, (7) indirect reduction of iron oxide by CO, and (8) iron reduction by H2. Curve fitting methods were successfully conducted with satisfying results (R2 >
0.90) calculating three parameters consisting of reaction rate constants, activation energies, and diffusion factors of each reaction. The interpretation of the calculated diffusion factors reveals that the reaction of gases inside pore might be inhibited by carbon deposition on the pore surface of iron ore. It revealed that the direct reduction by C predominates the overall reduction process.

A high-thermal-conductivity, high-durability phase-change composite using a carbon fibre sheet as a supporting matrix
Kaixin Dong, Nan Sheng, Deqiu Zou, Cheng Wang, Kenji Shimono, Tomohiro Akiyama, Takahiro Nomura
Applied Energy, 264, 114685, 114685, Elsevier BV, Apr. 2020, [Peer-reviewed], [Last author, Corresponding author], ［Internationally co-authored］, [International Magazine]
English, Scientific journal

Anisotropically enhanced heat transfer properties of phase change material reinforced by graphene-wrapped carbon fibers
Nan Sheng, Ruijie Zhu, Takahiro Nomura, Zhonghao Rao, Chunyu Zhu, Yoshitaka Aoki, Hiroki Habazaki, Tomohiro Akiyama
Solar Energy Materials and Solar Cells, 206, 110280, 110280, Elsevier BV, Mar. 2020, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
English, Scientific journal

Co-appearance of superconductivity and ferromagnetism in a Ca2RuO4 nanofilm crystal
Hiroyoshi Nobukane, Kosei Yanagihara, Yuji Kunisada, Yunito Ogasawara, Kakeru Isono, Kazushige Nomura, Keita Tanahashi, Takahiro Nomura, Tomohiro Akiyama, Satoshi Tanda
Scientific Reports, 10, 1, 3462, Springer Science and Business Media LLC, Feb. 2020, [Peer-reviewed], [International Magazine]
English, Scientific journal, By tuning the physical and chemical pressures of layered perovskite materials we can realize the quantum states of both superconductors and insulators. By reducing the thickness of a layered crystal to a nanometer level, a nanofilm crystal can provide novel quantum states that have not previously been found in bulk crystals. Here we report the realization of high-temperature superconductivity in Ca₂RuO₄ nanofilm single crystals. Ca₂RuO₄ thin film with the highest transition temperature T_c (midpoint) of 64 K exhibits zero resistance in electric transport measurements. The superconducting critical current exhibited a logarithmic dependence on temperature and was enhanced by an external magnetic field. Magnetic measurements revealed a ferromagnetic transition at 180 K and diamagnetic magnetization due to superconductivity. Our results suggest the co-appearance of superconductivity and ferromagnetism in Ca₂RuO₄ nanofilm crystals. We also found that the induced bias current and the tuned film thickness caused a superconductor-insulator transition. The fabrication of micro-nanocrystals made of layered material enables us to discuss rich superconducting phenomena in ruthenates.

Synthesis of AlN particles via direct nitridation in a drop tube furnace
Genki SAITO, Tatsuya SENDA, Keisuke ABE, Takahiro NOMURA, Tomohiro AKIYAMA
Journal of the Ceramic Society of Japan, 127, 11, 810, 817, Ceramic Society of Japan, 01 Nov. 2019, [Peer-reviewed], [Domestic magazines]
English, Scientific journal

蓄熱技術の最前線と社会実装への挑戦 高温用相変化マイクロカプセルの開発と応用展開
能村貴宏, 秋山友宏
化学工学, 83, 9, 513‐516, 05 Sep. 2019
Japanese

Modified preparation of Al2O3@Al-Si microencapsulated phase change material for high-temperature thermal storage with high durability over 3000 cycles
Nan Sheng, Chunyu Zhu, Hiroki Sakai, Yuta Hasegawa, Tomohiro Akiyama, Takahiro Nomura
Solar Energy Materials and Solar Cells, 200, 15, 109925, 109925, Elsevier BV, Sep. 2019, [Peer-reviewed], [Last author, Corresponding author], [International Magazine]
English, Scientific journal

Combustion synthesis of α-Si3N4 assisted by molten salt additives
Xuemei Yi, Qingda Li, Shota Suzuki, Senjing Zhang, Takahiro Nomura, Tomohiro Akiyama
Ceramics International, 45, 8, 10021, 10027, Elsevier BV, Jun. 2019, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
English, Scientific journal

Combustion Synthesis Ironmaking: Investigation on Required Carbon Amount in Raw Material from the Viewpoint of Adiabatic Flame Temperature Calculation
Keisuke Abe, Ade Kurniawan, Masafumi Sanada, Takahiro Nomura, Tomohiro Akiyama
Indonesian Journal of Chemistry, 19, 3, 696, 702, Universitas Gadjah Mada, 29 May 2019, [Peer-reviewed], [International Magazine]
English, Scientific journal, Combustion synthesis (CS) is a simple and very fast method to synthesize a target material. New ironmaking method via the CS using carbon-infiltrated iron ore was proposed, and the possible conditions for the method were investigated. Adiabatic flame temperatures (Tad) of the CS reaction, maximum reachable temperatures in an adiabatic system, were calculated to estimate the sample temperature during the CS. To reach the adiabatic temperature of 1811 K, 23.9, 27.9, and 29.3 wt.%-C were required for Fe2O3, Fe3O4, and FeO, respectively. When the carbon amount is higher than the calculated one, molten iron which is separated from slag components should be obtained via the CS.

Al/Al2O3 core/shell microencapsulated phase change material for high-temperature applications
Takahiro Nomura, Julalak Yoolerd, Nan Sheng, Hiroki Sakai, Yuta Hasegawa, Miki Haga, Tomohiro Akiyama
Solar Energy Materials and Solar Cells, 193, 281, 286, Elsevier BV, May 2019, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
English, Scientific journal

Thermal conductivity enhancement of erythritol phase change material with percolated aluminum filler
Nan Sheng, Kaixin Dong, Chunyu Zhu, Tomohiro Akiyama, Takahiro Nomura
Materials Chemistry and Physics, 229, 87, 91, Elsevier BV, May 2019, [Peer-reviewed], [Last author, Corresponding author], [International Magazine]
English, Scientific journal, This paper describes a high thermal conductive phase change composite (PCC) of erythritol and Al filler with percolating network. The PCCs with various Al amounts were prepared by both melt-dispersion method and hot-press (HP) method. The effective thermal conductivity of PCCs was measured, and the distribution status of the erythritol and Al filler was observed. The percolated filler network in the PCCs can be easily formed by HP method, which is important for enhancing the thermal conductivity of PCCs. The PCM particles with nonuniform particle size and high packing ratio is essential for the formation of filler percolating network. A high thermal conductivity of 30 W m(-1) K-1 can be obtained at a filler fraction of 42.2 vol%.

Cotton-derived carbon sponge as support for form-stabilized composite phase change materials with enhanced thermal conductivity
Nan Sheng, Takahiro Nomura, Chunyu Zhu, Hiroki Habazaki, Tomohiro Akiyama
Solar Energy Materials and Solar Cells, 192, 8, 15, Elsevier BV, Apr. 2019, [Peer-reviewed], [International Magazine]
English, Scientific journal, The practical use of organic phase change materials (PCMs) for solar thermal energy storage is limited by the leakage problem and the low thermal conductivity. As a good supporting and thermal conductive framework for organic PCM with shape-stability, three-dimensional carbon sponges are produced by the direct carbonization of low-cost and sustainable biomass cotton. The carbon sponges are consisted of aerogels of the cotton-derived hollow carbon fibers, which have both interconnecting network and high porosity. The vacuum impregnated paraffin@carbon sponge composites not only present leakage-proof shape stability and enhanced thermal conductivity, but also show high thermal storage energy density (> 200 J g(-1), slightly lower than the pure paraffin) and good cyclability. The results indicate that the shape-stable PCMs as supported by cotton-derived carbon sponges are potentially to be widely used for thermal energy conversion and storage, especially for solar energy utilization.

Synthesis of Al-25 wt% Si@Al2O3@Cu microcapsules as phase change materials for high temperature thermal energy storage
Sheng Nan, Zhu Chunyu, Sakai Hiroki, Akiyama Tomohiro, Nomura Takahiro
SOLAR ENERGY MATERIALS AND SOLAR CELLS, 191, 141, 147, Mar. 2019, [Peer-reviewed], [Last author, Corresponding author], [International Magazine]
English, Scientific journal

Vertically aligned carbon fibers as supporting scaffolds for phase change composites with anisotropic thermal conductivity and good shape stability
Sheng Nan, Zhu Ruijie, Dong Kaixin, Nomura Takahiro, Zhu Chunyu, Aoki Yoshitaka, Habazaki Hiroki, Akiyama Tomohiro
JOURNAL OF MATERIALS CHEMISTRY A, 7, 9, 4934, 4940, ROYAL SOC CHEMISTRY, 29 Jan. 2019, [Peer-reviewed], [International Magazine]
English, Scientific journal, The wide application of organic phase change materials for thermal energy storage and management is limited by their low thermal conductivity and poor shape stability. In this work, anisotropic thermally conductive and shape-stabilized phase change composites (PCCs) were successfully prepared with vertically aligned carbon fibers as supporting scaffolds. The aligned and hollow carbon fiber scaffolds with different densities were facilely fabricated by the direct carbonization of rolled cotton sheets with aligned and hollow cellulose fibers. PCCs were obtained by vacuum impregnation of paraffin wax. Because of the interconnected hollow carbon fiber frameworks with vertically aligned fibers and high porosity, PCCs present enhanced anisotropic thermal conductivity and good shape stability against leakage. The thermal conductivity in the axial direction along the fibers is higher than that in the lateral direction, since the aligned fiber scaffolds act as the thermal conduction pathway. The thermal conductivity of a PCC with a carbon ratio of 8.8 wt% is 0.77 W K-1 m(-1) (>3 times that of pure paraffin) in the axial direction, while the value in the lateral direction is 0.58 W K-1 m(-1). This work provides a novel strategy for designing anisotropic thermally conductive and shape-stabilized PCCs with potential applications in advanced thermal management and storage.

Steam Reforming of Tar Using Low-Grade Iron Ore for Hydrogen Production
Cahyono Rochim B, Bin Mansor Marwan, Nomura Takahiro, Hidayat Muslikhin, Budiman Arief, Akiyama Tomohiro
ENERGY & FUELS, 33, 2, 1296, 1301, 22 Jan. 2019, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
English, Scientific journal

Sr substitution effects on atomic and local electronic structure of Ca2AlMnO5+delta
Kunisada Yuji, Saito Genki, Hayami Kazuki, Nomura Takahiro, Sakaguchi Norihito
SURFACE AND INTERFACE ANALYSIS, 51, 1, 65, 69, Jan. 2019, [Peer-reviewed], [International Magazine]
English, Scientific journal

Combustion synthesis of AlN doped with carbon and oxygen
Saito Genki, Kunisada Yuji, Watanabe Takumi, Yi Xuemei, Nomura Takahiro, Sakaguchi Norihito, Akiyama Tomohiro
JOURNAL OF THE AMERICAN CERAMIC SOCIETY, 102, 1, 524, 532, Jan. 2019, [Peer-reviewed], [International Magazine]
English, Scientific journal

Microencapsulation of eutectic and hyper-eutectic Al-Si alloy as phase change materials for high-temperature thermal energy storage
Nomura Takahiro, Yoolerd Julalak, Sheng Nan, Sakai Hiroki, Hasegawa Yuta, Haga Miki, Saito Genki, Akiyama Tomohiro
SOLAR ENERGY MATERIALS AND SOLAR CELLS, 187, 255, 262, Dec. 2018, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
English, Scientific journal

Development of a microencapsulated Al-Si phase change material with high-temperature thermal stability and durability over 3000 cycles
Sheng Nan, Zhu Chunyu, Saito Genki, Hiraki Takehito, Haka Miki, Hasegawa Yuta, Sakai Hiroki, Akiyama Tomohiro, Nomura Takahiro
JOURNAL OF MATERIALS CHEMISTRY A, 6, 37, 18143, 18153, 12 Sep. 2018, [Peer-reviewed], [Last author, Corresponding author], [International Magazine]
English, Scientific journal

Reduction of mild-dehydrated, low-grade iron ore by ethanol
Ade Kurniawan, Keisuke Abe, Kouichi Ohashi, Takahiro Nomura, Tomohiro Akiyama
Fuel Processing Technology, 178, 156, 165, Elsevier B.V., Sep. 2018, [Peer-reviewed], [International Magazine]
English, Scientific journal, Low-grade iron ore with high combined water (CW) content (e.g., goethite) has been first dehydrated at low temperatures mildly to be slit-shaped nano-order pore, then has been reduced by ethanol (C2H5OH) charging under the heating conditions. Bioethanol as derived from biomass, regarded as a renewable and carbon-neutral resource, is a promising candidate as a reducing agent for ironmaking. In the experiments, ethanol was dropwise added to the mild-dehydrated, porous iron ore beds at heating conditions using the temperature-program. As a result, the ethanol was soon decomposed to CO and H2, which then reduced the iron oxides. Porous iron ore acts as a good catalyst for ethanol decomposition as it simultaneously reduces to metallic iron. Interestingly, iron oxides were reduced at a lower temperature, compared to conventional coal-based ironmaking in the blast furnace. Metallic Fe was obtained at only 750 °C, showing a reduction degree of 81%, due to the contribution of hydrogen reduction. The longer charging time of ethanol promotes the higher reduction degree as well as sufficient compositions of reducing gas (H2-CO) for the reduction process. The results of experiments using different iron ores revealed the general rule that the higher CW content in ore makes the larger surface area of the iron ore by mild-dehydration, causing higher reactivity in the reduction process. The results appealed that mild-dehydrated iron ore is good raw materials of bioethanol ironmaking, due to its nanopores.

Effects of reduction on the catalytic performance of limonite ore
Abe Keisuke, Kurniawan Ade, Nomura Takahiro, Akiyama Tomohiro
JOURNAL OF ENERGY CHEMISTRY, 27, 5, 1489, 1495, ELSEVIER SCIENCE BV, Sep. 2018, [Peer-reviewed], [International Magazine]
English, Scientific journal, The catalytic performance of Ni-containing limonite ore in the dry reforming reaction of methane (CH4 + CO2 -> 2H(2) + 2CO) was determined before and after hydrogen reduction, and under a flow of hydrogen. After hydrogen reduction, the limonite ore exhibited higher catalytic performance, because of the formation of Fe-Ni. However, the Fe in Fe-Ni was readily oxidized by the input CO2 gas, resulting in a rapid decrease in the catalytic performance of limonite ore. The performance decrease was due to a decrease in the Ni surface area; Ni could not dissolve in iron oxides and this caused segregation in the iron oxides. When the reaction was conducted under a hydrogen flow, the Fe-Ni was formed and maintained. Ni was highly dispersed in the Fe-Ni phase, resulting in greater surface area of Ni and higher conversion rate of CH4 and CO2. The catalytic performance of the limonite ore was inferior to the Ni/Al2O3 catalyst because the effect of catalyst support was small, however, the limonite ore was more stable during catalytic use and much cheaper than the Ni/Al2O3. (c) 2017 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.

Ultrafast Iron-Making Method: Carbon Combustion Synthesis from Carbon-Infiltrated Goethite Ore
Keisuke Abe, Ade Kurniawan, Kouichi Ohashi, Takahiro Nomura, Tomohiro Akiyama
ACS Omega, 3, 6, 6151, 6157, American Chemical Society, 07 Jun. 2018, [Peer-reviewed], [International Magazine]
English, Scientific journal, Carbon-infiltrated iron ores were prepared from a coal-tar solution and selected calcined iron sources (i.e., goethite (FeOOH) ore, high-grade hematite ore, and Fe2O3 reagent grain). A several hundred micrometer thick carbon layer was deposited on the surface of all iron sources. Because the tar solution successfully penetrated into its nanopores, only goethite ore possessed a significant amount of carbon in its interior nanopores. The carbon-infiltrated ores were heated rapidly in an oxygen atmosphere in the combustion synthesis experiments. Carbon combustion occurred at the ore surface, with the ore temperature increasing suddenly during the experiments. Fast reduction to metallic iron was observed only in the carbon-infiltrated goethite ore, regardless of the oxygen atmosphere. Close contact between the goethite ore and the carbon in its nanoporous interior facilitated the fast reduction. The apparent reduction reaction of goethite ore is akin to a direct reduction reaction (i.e., FeOx + C → FeOx-1 + CO).

Tar Decomposition over a Porous Iron Ore Catalyst: Experiment and Kinetic Analysis
Rochim B. Cahyono, Muslikhin Hidayat, Naoto Yasuda, Takahiro Nomura, Tomohiro Akiyama
Energy and Fuels, 32, 6, 7046, 7053, American Chemical Society, 17 May 2018, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
English, Scientific journal, In the pyrolysis process, tar material may cause operational problems, such as pipe plugging, condensation, and tar aerosol formation. An unusual approach should be introduced to solve carbon deposition over a catalyst, which was a serious problem in the tar decomposition process. The kinetic analysis was evaluated in detail by the proposed system, tar decomposition over a porous catalyst of iron ore. Decomposition of lignite tar exhibited similar profiles of H2 and CO generation, which was rising shortly at the beginning of the reaction because the ore catalyst still owned high activity and there was no carbon poisoning. However, the excessive carbon deposition also occurred simultaneously. Both the kinetic constant and deactivation factor were evaluated successfully using a simple proposed model with ranges of 0.1275-0.5523 and 1.7206-2.5310 s-1, respectively, at 500-700 °C. The activation energy was also calculated on the basis of the Arrhenius equation, which was 44.86 kJ/mol. The deactivation factor exhibited a similar tendency with the amount of carbon deposition within pores of iron ore. It means that the carbon deposition within pores of ore was highly affected by catalyt activity. However, the high carbon content within an inactive ore catalyst offered an extra benefit in the steel production as raw material. Therefore, the tar decomposition over a porous iron ore was a promising catalyst, which was a cheap and abundant natural resource. In addition, this proposed system also offered a solution for problems related to the raw material, energy, and environment in the ironmaking industry.

Formation of Nano-porous Structure in a Cathode at the Interface between Pt Electrode and YSZ during CO2 Electrolysis at 1,000°C
Yoshiaki Kashiwaya, Takahiro Nomura, Yohei Shiomi
High Temperature Materials and Processes, 37, 4, Walter de Gruyter GmbH and Co. KG, 26 Mar. 2018, [Peer-reviewed]
English, Scientific journal, The electrolysis of CO2 was investigated using a simple Pt/YSZ/Pt cell (yttria-stabilized zirconia (YSZ)). The cell performance increased drastically after applying the overvoltage of 4.0 V for ~5 min. The current density increased 30 times at 1.4 V and 11 times at 2.0 V. Using a laser microscope and field emission scanning electron microscopy (FE-SEM), the structural changes of the surface of the Pt electrode and the interface between the YSZ and Pt electrode were investigated to understand the reaction mechanism at the cathode for increasing the cell performance. The results showed that the Pt electrode surface became smooth after the experiment. Moreover, the interface between YSZ and the Pt cathode greatly changed after the electrolysis experiment, while that of the anode showed only a minor change. The structure of the cathode interface consisted of a 1-μm-thick nano-porous Pt layer and a micro-porous structure comprising YSZ and Pt. These structures are involved in CO2 electrolysis. Possible elementary reactions are also presented in this paper.

Formation of Different Si3N4 Nanostructures by Salt-Assisted Nitridation
Xiongzhang Liu, Ran Guo, Sengjing Zhang, Qingda Li, Genki Saito, Xuemei Yi, Takahiro Nomura
ACS Applied Materials and Interfaces, 10, 14, 11852, 11861, American Chemical Society, 14 Mar. 2018, [Peer-reviewed], [Last author], ［Internationally co-authored］, [International Magazine]
English, Scientific journal, Silicon nitride (Si3N4) products with different nanostructure morphologies and different phases for Si3N4 ceramic with high thermal conductivity were synthesized by a direct nitriding method. NaCl and NH4Cl were added to raw Si powders, and the reaction was carried out under a nitrogen gas flow of 100 mL/min. The phase composition and morphologies of the products were systemically characterized by X-ray diffraction, field emission scanning electron microscopy, and high-resolution transmission electron microscopy. At 1450 °C, the NaCl content was 30 wt %, the NH4Cl content was 3 wt %, and the maximum α-Si3N4 content was 96 wt %. The process of Si nitridation can be divided into three stages by analyzing the reaction schemes: in the first stage (25-900 °C), NH4Cl decomposition and the generation of stacked amorphous Si3N4 occurs
in the second stage (900-1450 °C), NaCl melts and Si3N4 generates
and in the third stage (>
1450 °C), α-Si3N4 → β-Si3N4 phase change and the evaporation of NaCl occurs. The products are made of two layers: a thin upper layer of nanowires containing different nanostructures and a lower layer mainly comprising fluffy, blocky, and short needlelike products. The introduction of NaCl and NH4Cl facilitated the evaporation of Si powders and the decomposition of Al2O3 from porcelain boat and furnace tube, which resulted in the mixing of N2, O2, Al2O, and Si vapors and generated AlxSiyOz nanowires with rough surfaces and lead to thin Si3N4 nanowires, nanobranches by the vapor-solid (VS), vapor-liquid-solid (VLS), and the double-stage VLS base and VS tip growth mechanisms.

Combustion synthesis of YAG:Ce phosphors via the thermite reaction of aluminum
Junpei Ohyama, Chunyu Zhu, Genki Saito, Miki Haga, Takahiro Nomura, Norihito Sakaguchi, Tomohiro Akiyama
Journal of Rare Earths, 36, 3, 248, 256, Chinese Society of Rare Earths, Mar. 2018, [Peer-reviewed], [International Magazine]
English, Scientific journal, Cerium-doped yttrium aluminum garnet (YAG:Ce) as a yellow phosphor for white light-emitting diodes (LEDs) was synthesized via a facile combustion method using Y2O3, CeO2, Al2O3, Al, and NaClO4 as raw materials. The combustion synthesis approach utilizes the strong exothermic oxidation of aluminum to realize a self-sustaining reaction. In this study, we investigated the effects of the ratios of Al2O3 to Al, fluxes, and coprecipitated materials as raw materials on the luminescence properties of the synthesized YAG:Ce phosphors. When the amount of Al2O3 x is varied, the combustion reaction proceeds at x ≤ 1.8, with x = 1.725 being the optimum condition for producing a high-performance product. When 5 wt% BaF2 is added, the luminescence intensity is significantly improved owing to a decrease of YAP (YAlO3) formation with improved uniformity. However, the addition of CaF2 and NaF does not improve the luminescence properties. To suppress the segregation of CeO2, we used the coprecipitated material Y2O3–CeO2 as a raw material. Unlike with separate addition of Y2O3 and CeO2, Ce ions are uniformly distributed in the coprecipitated material, resulting in improved luminescence properties. The combination of BaF2 and coprecipitated material significantly improves the internal quantum efficiency to 83.0%, which is close to that of commercial phosphors.

Integrated Pyrolysis-Tar Decomposition over Low-Grade Iron Ore for Ironmaking Applications: Effects of Coal-Biomass Fuel Blending
Ade Kurniawan, Keisuke Abe, Takahiro Nomura, Tomohiro Akiyama
Energy and Fuels, 32, 1, 396, 405, American Chemical Society, 18 Jan. 2018, [Peer-reviewed], [International Magazine]
English, Scientific journal, One problem associated with ironmaking is the depletion of carbonaceous material (e.g., coal) for iron reduction. A combination of coal and biomass (coal-biomass co-pyrolysis) provides an advantageous synergetic effect to overcome the disadvantage of using renewable raw materials, such as biomass. In this study, we investigated the effect of coal-biomass co-pyrolysis in integrated pyrolysis-tar decomposition over low-grade iron ore. Combined coal-biomass with biomass blending ratios (BBRs) of 0, 25, 50, 75, and 100% were studied by thermogravimetric analysis. A kinetic study on the co-pyrolysis using a double-distributed activation energy model has been conducted. Coal-biomass co-pyrolysis was also performed in integrated pyrolysis-tar decomposition over porous iron ore. The reference line method was used to identify the synergetic effect for each pyrolysis product. A synergetic effect of coal-biomass co-pyrolysis has also been found for decreasing char and heavy tar products as well as for increasing light tar, gas, and deposited carbon through chemical vapor infiltration (CVI) over porous iron ore. The highest carbon content of CVI ore (4.70%) was obtained when using BBR-25%.

High-temperature latent heat storage technology to utilize exergy of solar heat and industrial exhaust heat
Takahiro Nomura, Tomohiro Akiyama
Green Energy and Technology, 1207, 1224, Springer Verlag, 2018
English, In book, To utilize the exergy of solar and industrial exhaust heat, latent heat storage (LHS) using phase change materials (PCM) is quite attractive for its high heat storage capacity, constant-temperature of the heat supply, and repeatable utilization without degradation. In this article, general LHS technology is outlined first
then recent advances in the uses of LHS for high-temperature applications (over 100, °C) are discussed, with respect to each type of PCM (e.g., sugar alcohol, molten salt, and alloy). The prospects of future LHS technology are discussed regarding exergy.

Formation mechanisms of Si3N4 microstructures during silicon powder nitridation
Xiongzhang Liu, Xuemei Yi, Ran Guo, Qingda Li, Takahiro Nomura
CERAMICS INTERNATIONAL, 43, 18, 16773, 16779, ELSEVIER SCI LTD, Dec. 2017, [Peer-reviewed], [Last author], ［Internationally co-authored］, [International Magazine]
English, Scientific journal, Silicon nitride (Si3N4) was synthesized under a nitrogen gas flow (100 mL/min) using a molten salt nitriding method to investigate the effects of the temperature and NaCl content on the alpha-Si3N4 content in products and their micro-morphologies. Adding NaCl and beta-Si3N4 in silicon powders resulted in Si nitridation products divided into two layers. Analysis of the lower product using X-ray diffraction revealed a change in the alpha-Si3N4 content with changes in the temperature and NaCl content. Analysis of the lower and upper layers using scanning electron microscopy revealed that the upper layer contained Si3N4 nanowires, Si3N4 nanobelts, and clastic oxide impurities; the lower one contained short needle-like and blocky Si3N4. From the microstructures of the products, the product morphology related to that the dry mixing procedure did not correspond to homogenization of the starting Si-Si3N4-NaCl mixtures and the different concentrations of raw materials resulted in different morphologies.

Combustion synthesis of Ca-alpha-SiAlON:Eu2+ phosphors with different Ca concentrations and diluent ratios
Genki Saito, Yuji Kunisada, Norihito Sakaguchi, Takahiro Nomura, Tomohiro Akiyama
CERAMICS INTERNATIONAL, 43, 15, 12396, 12401, ELSEVIER SCI LTD, Oct. 2017, [Peer-reviewed], [International Magazine]
English, Scientific journal, Yellow Ca-alpha-SiAlON:Eu2+ phosphors for white light-emitting diodes (LEDs) were synthesized by a facile combustion synthesis method using CaO, Eu2O3, alpha-Si3N4, Si, and Al as raw materials. Ca concentrations and diluent ratios were optimized to improve their luminescence properties. The lattice constant and luminescence properties improved as x increased from 0.4 to 1.2 in Ca(x)Si(12-(m+n))Al(m+n)OnN(16-n):En(0.06). The optimum value was x = 1.2. Scanning transmission electron microscopy combined with energy dispersive X-ray analysis detected segregation of Ca and Eu at grain boundaries, which decreased luminescence behavior in the x = 1.4 sample. The influence of Si and Si3N4 diluents was investigated by varying the diluent ratio phi = (CaO + Eu2O3 + alpha-Si3N4)/(CaO + Eu2O3 + a-Si3N4 + Al + Si). Changes in temperature and flame propagation speed were measured during combustion synthesis using two thermocouples. When phi, was less than 0.5, the combustion temperature exceeded 1600 degrees C and the synthesized material contained an amount of the high-temperature beta-SiAlON phase. At phi > 0.7, the reaction temperature fell below 1200 degrees C, and unreacted raw materials remained. The optimum value of phi was 0.6. The internal quantum efficiency of the product synthesized at x = 1.2 and (I, = 0.6 was approximately 35% under 450-nm excitation. According to electron probe X-ray microanalysis, composition varied within individual synthesized particles, which may explain the decrease in emission behavior relative to a commercial product.

Microencapsulated phase change materials with high heat capacity and high cyclic durability for high-temperature thermal energy storage and transportation
Takahiro Nomura, Nan Sheng, Chunyu Zhu, Genki Saito, Daiki Hanzaki, Takehito Hiraki, Tomohiro Akiyama
APPLIED ENERGY, 188, 15, 9, 18, ELSEVIER SCI LTD, Feb. 2017, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
English, Scientific journal, Latent heat storage (LHS) technology employing phase change materials (PCMs) has received great attention as an alternative to conventional solid sensible heat storage (SHS) for future high-temperature energy utilisation systems. In this study, we report the synthesis of a core-shell type microencapsulated PCM (MEPCM) consisting of AI-25 wt% Si microspheres (mean diameter of 363 pm and melting temperature of 577 degrees C) as the core (PCM) and Al2O3 as the shell. The MEPCM was prepared in two steps involving (1) the formation of an AlOOH precursor shell on the PCM microspheres by a hydroxide precipitation process in hot water and (2) heat-oxidation treatment in an O-2 atmosphere to form a stable Al2O3 shell. In particular, the effects of heat oxidation temperature on the shell morphology, shell crystal structure, mechanical strength, heat capacity, and cyclic durability of the prepared MEPCMs were examined. The resultant MEPCM is composed of a stable alpha-Al2O3 shell and Al-25 wt% Si core with an effective void inside the core to allow for volume expansion of the PCMs during solid-liquid phase transitions. The heat capacity measured for this material is five times higher than that of conventional solid SHS materials. Additionally, the MEPCM exhibits excellent durability up to 300 heating and cooling cycles under oxygen atmosphere. Consequently, it can potentially be used in the next-generation LHS-based high-temperature thermal energy storage and transportation systems. (C) 2016 Elsevier Ltd. All rights reserved.

High-temperature latent heat storage technology to utilize exergy of solar heat and industrial exhaust heat
Takahiro Nomura, Tomohiro Akiyama
INTERNATIONAL JOURNAL OF ENERGY RESEARCH, 41, 2, 240, 251, WILEY, Feb. 2017, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
English, Scientific journal, Latent heat storage (LHS) using phase change materials is quite attractive for utilization of the exergy of solar energy and industrial exhaust heat because of its high-heat storage capacity, heat storage and supply at constant temperature, and repeatable utilization without degradation. In this article, general LHS technology is outlined, and then recent advances in the uses of LHS for high-temperature applications (over 100 degrees C) are discussed, with respect to each type of phase change material (e. g., sugar alcohol, molten salt, and alloy). The prospects of future LHS systems are discussed from a principle of exergy recuperation. In addition, the technologies to minimize exergy loss in the future LHS system are discussed on the basis of the thermodynamic analysis by 'thermodynamic compass'. Copyright (C) 2016 John Wiley & Sons, Ltd.

Atomic and Local Electronic Structures of Ca(2)AIMnO(5+delta) as an Oxygen Storage Material
Genki Saito, Yuji Kunisada, Kazuki Hayami, Takahiro Nomura, Norihito Sakaguchi
CHEMISTRY OF MATERIALS, 29, 2, 648, 655, AMER CHEMICAL SOC, Jan. 2017, [Peer-reviewed], [International Magazine]
English, Scientific journal, We investigated the atomic and local electronic structures of Ca(2)AIMnO(5+delta) to assess its potential as an oxygen storage material. High-angle annular dark-field scanning transmission electron microscopy was used to investigate structural changes in the material during oxygen storage. We found that the AlO4 tetrahedra convert to AlO6 octahedra during such a process. According to the Mn L-edge electron energy-loss near-edge structure (ELNES) measurements, the Mn oxidation state increased from +3 to +4 on oxygen storage. The observed site-resolved oxygen K-ELNES and first-principles electronic structure calculations showed that each nonequivalent oxygen site has different characteristics, corresponding to local chemical bonding and oxygen intake and release. For Ca(2)AIMnO(5), the prepeak intensity was higher at MnO6 octahedral sites, indicating covalent bonding between the oxygen and Mn atoms. After oxygen storage, the ELNES spectra revealed that the Jahn Teller distortion of the Mn sites was suppressed by the increase in the Mn oxidation state; furthermore, the spectra indicate that Mn octahedron shrank in the z-direction, accompanied by an increase in Mn O covalent bonding, thus providing sufficient space to form octahedral AlO6. Consequently, we found that the reversible oxygen storage ability is related to the canceling of the volume changes of the Mn and Al octahedra. The electrons in Mn 3d orbitals play an important role in this structural change.

Enhanced cycling performance of surface-doped LiMn2O4 modified by a Li2CuO2-Li2NiO2 solid solution for rechargeable lithium-ion batteries
Cheng-Gong Han, Chunyu Zhu, Genki Saito, Nan Sheng, Takahiro Nomura, Tomohiro Akiyama
ELECTROCHIMICA ACTA, 224, 10, 71, 79, PERGAMON-ELSEVIER SCIENCE LTD, Jan. 2017, [Peer-reviewed], [International Magazine]
English, Scientific journal, A series of surface-doped LiMn2O4 samples modified by a Li2CuO2-Li2NiO2 solid solution were synthesized using a simple and facile sol-gel method to achieve the enhanced cycling performance, especially at elevated temperatures. The corresponding phase structure and morphology were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The modified layer on the surface of LiMn2O4 particles, featuring a LiNi delta Mn2-delta O4-like phase, together with a Li2CuO2-Li2NiO2 solid solution, as confirmed by XRD and transmission electron microscopy (TEM), plays a key role in alleviating the dissolution of manganese, thus enhancing the cycling performance and rate capability relative to bare LiMn2O4. The 0.5 wt.%-modified LiMn2O4 sample delivers a discharge capacity of 113 mAh g(-1), and a capacity retention of 93.2% following 300 cycles at 1C and 25 degrees C, which is higher than the values of 96 mAh g(-1) and 81.2% for bare LiMn2O4. In addition, at 55 degrees C, a capacity retention of 81.2% at 1C is obtained for the 0.5 wt.%-modified LiMn2O4 sample after 200 cycles, compared to 70.0% for bare LiMn2O4. Modifying the surface of the latter by a LiNi delta Mn2-delta O4-like phase mixed with a Li2CuO2Li2NiO2 solid solution, is an effective strategy for improving electrochemical properties. (C) 2016 Published by Elsevier Ltd.

High thermal conductivity phase change composite with a metal-stabilized carbon-fiber network
Takahiro Nomura, Chunyu Zhu, Sheng Nan, Kazuki Tabuchi, Shuangfeng Wang, Tomohiro Akiyama
APPLIED ENERGY, 179, 1, 1, 6, ELSEVIER SCI LTD, Oct. 2016, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］, [International Magazine]
English, Scientific journal, To enhance the thermal conductivity of phase change materials (PCM) such as sugar alcohol and molten salts, the preparation of a phase change composite (PCC) with a PCM and a filler with high thermal conductivity has been widely investigated. Although many reported PCCs have high thermal conductivity, the stability during thermal cycling endurance is often too low for practical use. This paper describes the development of a PCC with both high thermal conductivity and high cyclic durability. The PCCs were prepared by a hot -pressing method. Erythritol (melting point: 118 degrees C, thermal conductivity: 0.73 W m(-1) K-1) was used as a PCM, and carbon fiber (thermal conductivity: 900 W m(-1) K-1 in the fiber direction) and indium particles (thermal conductivity: 82.8 W m(-1) K-1) were used as the high thermal conductivity fillers. The effective thermal conductivity of the PCC was measured using the laser flash method and the network structures were analyzed using energy dispersive spectroscopy and scanning electron microscopy. Thermal cycling tests through the melting and solidification phases of the erythritol were performed to investigate the cyclic durability of the PCCs. We found that the indium particles melted during hot pressing, welding together the carbon fiber to produce a stable percolating network, which significantly enhanced the thermal conductivity and cyclic endurance of the PCCs. (C) 2016 Elsevier Ltd. All rights reserved.

Optimization of the Dehydration Temperature of Goethite to Control Pore Morphology
Genki Saito, Takahiro Nomura, Norihito Sakaguchi, Tomohiro Akiyama
ISIJ INTERNATIONAL, 56, 9, 1598, 1605, IRON STEEL INST JAPAN KEIDANREN KAIKAN, 15 Sep. 2016, [Peer-reviewed], [Domestic magazines]
English, Scientific journal, This study optimizes the dehydration temperature of goethite to control pore morphology. The pore morphology was characterized by using transmission electron microscopy and the nitrogen adsorption method. When the goethite was dehydrated at 200-250 degrees C, slit-like pores with a width lesser than 2 nm were formed along the [010] direction. These slit-like pores changed to spherical micropores (300-500 degrees C), and eventually disappeared (600-800 degrees C). Compared to the synthetic goethite, natural goethite has a lower crystallinity and smaller primary particle size of under 100 nm. The natural goethite before dehydration contained 4 nm pores as cracks that remained even after heating to 800 degrees C. In the case of natural goethite, the optimum dehydration temperature for higher surface area and pore volume was 350 degrees C, which was higher than that of 250 degrees C for the synthetic goethite.

Limonitic Laterite Ore as a Catalyst for the Dry Reforming of Methane
Keisuke Abe, Genki Saito, Takahiro Nomura, Tomohiro Akiyama
ENERGY & FUELS, 30, 10, 8457, 8462, AMER CHEMICAL SOC, 09 Aug. 2016, [Peer-reviewed], [International Magazine]
English, Scientific journal, We investigated four catalysts for the dry reforming of methane: three Ni-containing natural iron ores (LN, SN, and NN ores) and one Ni-supported ore (Ni-supported NN ore) to solve the problems about unused high-temperature waste heat and CO2 emission in the steel industry. The CO2 conversion ratio was highest for the LN ore (1.18 wt '% Ni), followed by Ni-supported NN (1.0 wt % Ni), SN (0.30 wt % Ni), and NN (0 wt % Ni) ores. The CO2 conversion ratio of the LN ore was much higher than that of the Ni-supported NN ore, despite the fact that they contained almost the same amount of Ni. This is because the LN ore had a higher surface area and a higher nickel dispersion. Transmission electron microscopy with energy dispersive X-ray spectroscopy revealed that Ni existed quite finely in the LN ore but existed as a larger particle (20 nm) in the Nisupported NN ore. Smaller Ni particles have a higher surface area, resulting in the higher catalytic performance of the LN ore. More CO2 and CH4 reacted and higher amounts of H-2 and CO were produced with the LN ore catalyst compared to the uncatalyzed reaction. The LN ore showed more reduction at higher temperatures, and metallic iron and nickel were produced above 1073 K; reduction did not progress past Fe3O4 at lower temperatures.

Twin formation in hematite during dehydration of goethite
Genki Saito, Yuji Kunisada, Takahiro Nomura, Norihito Sakaguchi, Tomohiro Akiyama
PHYSICS AND CHEMISTRY OF MINERALS, 43, 10, 749, 757, SPRINGER, 29 Jul. 2016, [Peer-reviewed], [International Magazine]
English, Scientific journal, Twin formation in hematite during dehydration was investigated using X-ray diffraction, electron diffraction, and high-resolution transmission electron microscopy (TEM). When synthetic goethite was heated at different temperatures between 100 and 800 degrees C, a phase transformation occurred at temperatures above 250 degrees C. The electron diffraction patterns showed that the single-crystalline goethite with a growth direction of [001](G) was transformed into hematite with a growth direction of [100](H). Two non-equivalent structures emerged in hematite after dehydration, with twin boundaries at the interface between the two variants. As the temperature was increased, crystal growth occurred. At 800 degrees C, the majority of the twin boundaries disappeared; however, some hematite particles remained in the twinned variant. The electron diffraction patterns and high-resolution TEM observations indicated that the twin boundaries consisted of crystallographically equivalent prismatic (100) (010), and (10) planes. According to the total energy calculations based on spin-polarized density functional theory, the twin boundary of prismatic (100) screw had small interfacial energy (0.24 J/m(2)). Owing to this low interfacial energy, the prismatic (100) screw interface remained after higher-temperature treatment at 800 degrees C.

Macro-encapsulation of metallic phase change material using cylindrical-type ceramic containers for high-temperature thermal energy storage
Ryo Fukahori, Takahiro Nomura, Chunyu Zhu, Nan Sheng, Noriyuki Okinaka, Tomohiro Akiyama
APPLIED ENERGY, 170, 15, 324, 328, ELSEVIER SCI LTD, May 2016, [Peer-reviewed], [Corresponding author], [International Magazine]
English, Scientific journal, High-temperature heat storage is of growing importance for advanced solar energy utilization and waste heat recovery systems. Latent heat storage technology using alloys as phase change materials (PCM) is a promising option since it can achieve a thermal energy storage system with high heat storage density and high heat exchange rate because of the large latent heat and high thermal conductivity of metallic PCMs. Encapsulation of PCM is essential for its successful use, however, the encapsulation is very difficult owing to the high corrosivity of the metallic PCM and its volume expansion during the solid-liquid phase change. So far, the technology for encapsulating metallic PCMs has not been achieved. This study proposes the use of ceramic containers comprising a cap and a cup for macro-encapsulation of metallic PCMs, and a sealing method of the containers to endure the thermal stress from volume expansion during the phase change. The resulting PCM capsule has excellent corrosive resistance and cycling performance. (C) 2016 Elsevier Ltd. All rights reserved.

Thermal analysis of Al-Si alloys as high-temperature phase-change material and their corrosion properties with ceramic materials
Ryo Fukahori, Takahiro Nomura, Chunyu Zhu, Nan Sheng, Noriyuki Okinaka, Tomohiro Akiyama
APPLIED ENERGY, 163, 1, 1, 8, ELSEVIER SCI LTD, Feb. 2016, [Peer-reviewed], [Corresponding author], [International Magazine]
English, Scientific journal, This study reports the thermal analysis of Al-Si alloys as candidate high-temperature phase-change materials (PCM) for temperatures above 500 degrees C and the corrosion behavior of the alloys with ceramic materials. Four Al-Si alloys with different Si contents (0-25 wt%) were selected as PCMs. Engineering ceramics such as Al2O3, AIN, Si3N4, SiC, and SiO2 were used for corrosion tests. Thermal analysis showed that the Al-Si alloys were better than conventional molten salts as PCM candidates because of the high heat storage capacity and high thermal conductivity of the alloys. The corrosion tests revealed that Al2O3, AIN, and Si3N4 showed high corrosion resistance to molten Al-Si alloys; therefore, these ceramics were suitable as structural materials for a latent heat storage (LHS) system using Al-Si alloys. These results demonstrate the feasibility of high-temperature LHS systems using Al-Si alloys as the PCMs and ceramics as structural materials. (C) 2015 Elsevier Ltd. All rights reserved.

Enhancement of oil palm empty fruit bunch char by impregnation of pyrolytic carbon from tar vapor decomposition
Alya Naili Rozhan, Rochim Bakti Cahyono, Takahiro Nomura, Mohd Hanafi Ani, Hamzah Mohd Salleh, Tomohiro Akiyama, Hadi Purwanto
JOURNAL OF RENEWABLE AND SUSTAINABLE ENERGY, 8, 1, 013110, AMER INST PHYSICS, Feb. 2016, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
English, Scientific journal, This paper describes a technology for condensable vapor from pyrolysis (often referred to as "tar") of oil palm empty fruit bunch, EFB, to be collected-by EFB char substrate-in the form of pyrolytic carbon to produce a value-added EFB char and to make EFB able to be utilized as a supplementary solid fuel. Chemical vapor infiltration method was employed at atmospheric pressure for tar vapor to undergo secondary decomposition to produce pyrolytic carbon to be deposited within porous char. Porous char in a packed bed was used as the substrate, and impregnated with pyrolytic carbon using tar vapor as a reactant. Char substrate was prepared by slowly heating coarse EFB particles in the packed bed to 400 degrees C in nitrogen atmosphere. Tar vapor was obtained from fast pyrolysis of fine EFB particles at 400-700 degrees C, and the weight ratio of fine EFB particles-the tar source-to char substrate was increased from 0.5 to 4.0. The amount of carbon contents of the resultant products by this process was compared to those without carbon deposition. After carbon deposition, EFB char has substantially increased in carbon contents which promise higher heating values than those of EFB char with no carbon deposition. The resultant products can be used as a partial substitute to the now depleting fossil fuels. (C) 2016 AIP Publishing LLC.

Shape-stabilized phase change composite by impregnation of octadecane into mesoporous SiO2
Takahiro Nomura, Chunyu Zhu, Nan Sheng, Kazuki Tabuchi, Akihito Sagara, Tomohiro Akiyama
SOLAR ENERGY MATERIALS AND SOLAR CELLS, 143, 424, 429, ELSEVIER SCIENCE BV, Dec. 2015, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
English, Scientific journal, We developed shape-stabilized phase change composites (PCCs) for building materials with high heat-storage density by vacuum impregnation of the phase change material (PCM) octadecane into mesoporous SiO2. We examined the effects of the average pore size of mesoporous SiO2 on the melting point and latent heat of the PCCs. Cyclic tests of melting and freezing were performed to evaluate leakage and degradation of the PCCs. The thermophysical properties of the PCCs were measured by differential scanning calorimetry, and the following results were obtained: (1) The impregnation ratio of the composites was above 0.95; therefore, almost all pores were completely filled with PCM. (2) The melting point of the PCMs decreased with decreasing average pore diameter, and the melting point was established as a function of average pore diameter from the Gibbs-Thomson equation, taking into account the existence of a nonfreezing layer on the surface of the pore wall. (3) The octadecane/mesoporous SiO2 composites retained the full amount of impregnated PCM, even after cyclic heating and cooling. (C) 2015 Elsevier B.V. All rights reserved.

Fabrication of paraffin@SiO2 shape-stabilized composite phase change material via chemical precipitation method for building energy conservation
Ruilian Luo, Shuangfeng Wang, Tingyu Wang, Chunyu Zhu, Takahiro Nomura, Tomohiro Akiyama
ENERGY AND BUILDINGS, 108, 373, 380, ELSEVIER SCIENCE SA, Dec. 2015, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
English, Scientific journal, A novel paraffin@SiO2 shape-stabilized composite phase change material (ss-CPCM) was fabricated by chemical precipitation process using sodium silicate precursor. Various techniques were used to characterize the as-prepared paraffin@SiO2 ss-CPCM so as to investigate its structure and thermal properties, including Fourier transforms infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and thermal conductivity measurement. The SEM results show that the microstructures of the prepared ss-CPCM are some uniform submicron particles. The FUR and XRD results showed that there was no chemical interaction between paraffin and SiO2 matrix. The DSC analysis results indicated that the paraffin@SiO2 ss-CPCM achieved high encapsulation efficiency and desirable latent heat storage capability. The thermal conductivity of the composite was also significantly improved compared with pure paraffin. According to the TGA results and the thermal cycling tests, the prepared ss-CPCMs had a good thermal stability. The prepared paraffin@SiO2 ss-CPCM with enhanced heat transfer and phase change properties holds great promise for building energy conservation owing to the low cost of raw materials and the simple synthetic technique. (C) 2015 Elsevier B.V. All rights reserved.

Solution combustion synthesis of Brownmillerite-type Ca2AlMnO5 as an oxygen storage material
Takahiro Nomura, Chunyu Zhu, Nan Sheng, Ryota Murai, Tomohiro Akiyama
JOURNAL OF ALLOYS AND COMPOUNDS, 646, 15, 900, 905, ELSEVIER SCIENCE SA, Oct. 2015, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
English, Scientific journal, Brownmillerite-type Ca2AlMnO5 exhibits remarkable oxygen uptake/release capability, and therefore is a promising material for achieving energy efficient air separation. This study investigates optimized conditions for the glycine-nitrate-based solution combustion synthesis (SCS) of Ca2AlMnO5. The effects of glycine content and duration of heat treatment on the morphology, crystallinity, and oxygen uptake/release performance of the products were investigated. Single phase Ca2AlMnO5, whose maximum reversible oxygen uptake/release capacity is about 3.0 wt%, was successfully synthesized by combination of SCS with various quantities of glycine and heat treatment at 1250 degrees C for various lengths of time. Greater crystallinity and larger capacities for reversible oxygen uptake/release were obtained from products prepared with longer periods of heat treatment. Single phase Ca2AlMnO5 can be synthesized by a combination of SCS and just 1 min of heat treatment at 1250 degrees C. (C) 2015 Elsevier B.V. All rights reserved.

High thermal conductivity phase change composite with percolating carbon fiber network
Takahiro Nomura, Kazuki Tabuchi, Chunyu Zhu, Nan Sheng, Shuangfeng Wang, Tomohiro Akiyama
APPLIED ENERGY, 154, 15, 678, 685, ELSEVIER SCI LTD, Sep. 2015, [Peer-reviewed], [Lead author, Corresponding author], ［Internationally co-authored］, [International Magazine]
English, Scientific journal, Latent heat storage (LHS) using phase change materials (PCM) is a promising technology for the effective use of solar and industrial exhaust heat. However, the heat transfer rate of an LHS system is severely limited by the low thermal conductivity of the PCM. Therefore, this paper describes the development of a high thermal conductivity phase change composite (PCC) with a percolating network of a high thermal conductivity filler. The relationship between the effective thermal conductivity of the FCC and the network structure of the filler was investigated. The FCC were prepared by the conventional melt-dispersion (MD) method and a novel hot-press (HP) method. Erythritol (melting point: 118 degrees C, thermal conductivity: 0.73 W m(-1) K-1) was used as the PCM, and carbon fiber (thermal conductivity: 900W m(-1) K-1 in the fiber direction) was used as the high thermal conductivity filler. The effective thermal conductivity of the PCC was measured by the laser flash method and the network structures were observed by energy dispersive spectroscopy using a scanning electron microscope. As a result, we observed that the percolating filler network in the PCC could be easily formed by the HP method, presenting a higher thermal conductivity with less filler additive than the FCC fabricated by the MD method. Additionally, we found that PCM raw materials with a high packing ratio accelerated the formation of the percolating filler network. (C) 2015 Elsevier Ltd. All rights reserved.

Microencapsulation of Metal-based Phase Change Material for High-temperature Thermal Energy Storage
Takahiro Nomura, Chunyu Zhu, Nan Sheng, Genki Saito, Tomohiro Akiyama
SCIENTIFIC REPORTS, 5, 9117, NATURE PUBLISHING GROUP, 13 Mar. 2015, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
English, Scientific journal, Latent heat storage using alloys as phase change materials (PCMs) is an attractive option for high-temperature thermal energy storage. Encapsulation of these PCMs is essential for their successful use. However, so far, technology for producing microencapsulated PCMs (MEPCMs) that can be used above 500 degrees C has not been established. Therefore, in this study, we developed Al-Si alloy microsphere MEPCMs covered by alpha-Al2O3 shells. The MEPCM was prepared in two steps: (1) the formation of an AlOOH shell on the PCM particles using a boehmite treatment, and (2) heat-oxidation treatment in an O-2 atmosphere to form a stable alpha-Al2O3 shell. The MEPCM presented a melting point of 573 degrees C and latent heat of 247 J g(-1). The cycling performance showed good durability. These results indicated the possibility of using MEPCM at high temperatures. The MEPCM developed in this study has great promise in future energy and chemical processes, such as exergy recuperation and process intensification.

Utilization of Low Grade Iron Ore (FeOOH) and Biomass Through Integrated Pyrolysis-tar Decomposition (CVI process) in Ironmaking Industry: Exergy Analysis and its Application
Rochim Bakti Cahyono, Naoto Yasuda, Takahiro Nomura, Tomohiro Akiyama
ISIJ INTERNATIONAL, 55, 2, 428, 435, IRON STEEL INST JAPAN KEIDANREN KAIKAN, 15 Feb. 2015, [Peer-reviewed], [Domestic magazines]
English, Scientific journal, Effective utilization of low grade iron ore (FeOOH) and biomass represents a promising method to reduce the dependency on fossil fuels and decrease raw material costs in the ironmaking industry. A process system diagram was made and a comparison of exergy losses in conventional methods was conducted to evaluate the proposed system, integrated pyrolysis-tar decomposition over a porous ore through Chemical Vapor Infiltration (CVO process. As the main product, the CVI ore was employed for energy storage based on carbon deposition and pre-reduced ore, Fe3O4 as a product of proposed system that consisted of three units: pyrolysis, CVI, and dehydration-separation. The exergy of CVI ore increased significantly owing to exergy recovery through tar decomposition. In the basis of 3.86% wt carbon deposition (experimental value) and producing of 1 000 kg metallic Fe, the exergy loss of the proposed system was found to decrease by about 17.6% compared to that in conventional systems by the recovery of both chemical and thermal tar exergy. The exergy loss decreased drastically to 37.0% when the expected carbon deposition was attained (10%wt). The CVI ore offered great chance to replace the coke breeze as a heat source in sinter plant. With regard to experimental value, the sinter plant could be operated without using additional coke breeze when the CVI ore content was 70% to total input ore. The total enthalpy of CVI ore consisted of the oxidation of deposited carbon and Fe3O4 in the ratio of 60.2% and 39.8%, respectively. Based on these results, the proposed system proffered effective biomass and low grade ore utilization as well as led to decrease in CO2 emissions by the ironmaking industry.

Improvement on Heat Release Performance of Direct-contact Heat Exchanger Using Phase Change Material for Recovery of Low Temperature Exhaust Heat
Takahiro Nomura, Masakatsu Tsubota, Noriyuki Okinaka, Tomohiro Akiyama
ISIJ INTERNATIONAL, 55, 2, 441, 447, IRON STEEL INST JAPAN KEIDANREN KAIKAN, 15 Feb. 2015, [Peer-reviewed], [Lead author], [Domestic magazines]
English, Scientific journal, Latent heat storage using a phase change material (PCM) is a promising method for utilizing the exhaust heat from steelworks. The purpose of this study was to improve the heat release performance of a direct-contact heat exchanger using a PCM and heat transfer oil (HTO). Erythritol (with a melting point of 391 K), which is a kind of sugar alcohol, was selected as a PCM. A vertical stainless steel cylinder with an inner diameter of 200 mm and height of 1 400 mm was used as the heat storage unit (HSU). A ring-shaped injector with 18 holes positioned vertically downward was placed at the bottom of the HSU. Each hole in this injector had a diameter of 2.5 mm. We investigated the effects of the height of the PCM in the HSU, the HTO flow rate, and an increase in the number of injection-nozzle holes on the temperature effectiveness and heat exchange rate as indices of the heat release performances. As results, we found that an increase in the number of nozzle holes accelerated the uniform distribution of the HTO in the liquid PCM, prevented the HTO drift flow and adverse solidification of the PCM, and improved the heat release performance under the condition of a high HTO flow rate.

Effect of Applied Voltage on the Current Density of CO₂ Electrolysis in High Temperature
Yoshiaki Kashiwaya, Yohei Shiomi, Takahiro Nomura, Masakatsu Hasegawa
ISIJ International, 55, 2, 392, 398, Iron and Steel Institute of Japan, 15 Feb. 2015, [Peer-reviewed], [Domestic magazines]
English, Scientific journal, Reductions in CO2 emission can be achieved directly through CO2 capture and storage (CCS), a method that is particularly effective when used with large CO2 emitters such as electrical power plants and iron and steel mills. Solid-oxide electrolysis presents an alternative means of reducing CO2 that can use some of the CO2 captured by CCS as a source of electrolysis. In addition, unused heat generated by steel-making and through renewable sources (e.g., solar and wind) can be utilized for high-temperature electrolysis. This study investigated the effect of applying a high voltage of between 2.5 and 4.0 V to common electrolytic materials (YSZ and Pt), and found that although the initial current density of a new cell is very low, it increases drastically upon application of a high voltage. The results of FE-SEM observation revealed that the interface between the YSZ and Pt electrode moves into the YSZ by about 70 mu m, and consists of a nano- and micro-porous structure that reduces the resistivity and gas diffusivity.

Ironmaking system including coproduction of carbon-loaded iron oxide and reformed coke oven gas by chemical vapor infiltration process
Takahiro Nomura, Rochim B. Cahyono, Tomohiro Akiyama
Journal of Sustainable Metallurgy, 1, 2, 115, 125, 14 Feb. 2015, [Peer-reviewed], [Lead author], ［Internationally co-authored］, [International Magazine]
English, Scientific journal

Ironmaking process using carbon deposition by chemical vapor infiltration
R. B. Cahyono, T. Nomura, T. Akiyama
Proceedings. Asia Steel International Conference, 2015, 290, 291, 2015
English, International conference proceedings

Estimation of thermal endurance of multicomponent sugar alcohols as phase change materials
Takahiro Nomura, Chunyu Zhu, Akihito Sagara, Noriyuki Okinaka, Tomohiro Akiyama
APPLIED THERMAL ENGINEERING, 75, 481, 486, PERGAMON-ELSEVIER SCIENCE LTD, Jan. 2015, [Peer-reviewed], [Lead author], [International Magazine]
English, Scientific journal, This study investigates the thermal endurance of sugar alcohols and their eutectic mixtures as phase-change materials (PCMs). Three sugar alcohols (mannitol, dulcitol, and inositol) and their eutectic mixtures were selected as the PCM candidates. First, the thermophysical properties of the single- and multicomponent sugar alcohols were characterized using differential scanning calorimetry. Second, the thermal endurance of the PCM candidates was estimated by constant-temperature kinetics based on the degradation of the latent heat of the PCM candidates. The results showed that mannitol, dulcitol, inositol, and their eutectic mixtures had melting points and latent heats of over 423 K and 200 kJ/kg, respectively. The kinetic analysis of the PCM candidates showed that the first-order reaction rate equation was suitable for analyzing the degradation of the latent heat of the sugar alcohols. The degradation periods increased with decrease of melting temperatures of each sugar alcohol. In particular, the dulcitol/mannitol eutectic mixture showed the longest degradation periods of 9817 ks, which is 5.68 and 6.85 times greater than those of pure mannitol and dulcitol, respectively. These observations indicated that eutectic mixtures of sugar alcohols were promising and alternative PCM candidates in the 373-473 K temperature range. (C) 2014 Elsevier Ltd. All rights reserved.

Improvement in thermal endurance of D-mannitol as phase-change material by impregnation into nanosized pores
Akihito Sagara, Takahiro Nomura, Masakatsu Tsubota, Noriyuki Okinaka, Tomohiro Akiyama
MATERIALS CHEMISTRY AND PHYSICS, 146, 3, 253, 260, ELSEVIER SCIENCE SA, Aug. 2014, [Peer-reviewed], [International Magazine]
English, Scientific journal, This paper describes the control of the melting point and improvement of the thermal endurance of D-mannitol (melting point T-m = 440 K) as a phase-change material (PCM) by vacuum impregnation of the PCM into nanosized pores of porous SiO2 grains. First, we examined the effects of the average pore size (D-P) of porous SiO2 on T-m and latent heat (L) of PCM/SiO2 composites. Second, we investigated the thermal endurance of the composites using constant temperature kinetics based on L of the PCM and composites. Third, we performed cyclic tests of melting and freezing on the composite to evaluate leakage of the PCM. Thermophysical properties of the samples were measured by differential scanning calorimetry, and the following results were obtained: (1) The impregnation ratio of the composites was 0.91-0.99; therefore, almost all pores were completely filled with the PCM. (2) T-m shifted to lower temperature with smaller D-P, reaching 413 K in case of the PCM/SiO2 composite with a D-P of 11.6 nm (3) T-m was derived as a function of D-P from the Gibbs Thomson equation taking into account the existence of a nonfreezing layer on the surface of the pore wall. (4) The duration of thermal degradation of the PCM/SiO2 composite with D-P = 11.6 nm was three times longer than that of the pure PCM at a temperature that is 10 K more than each melting point. (5) The PCM/SiO2 composite with D-P = 11.6 nm can use as a shape-stable PCM composite without leakage of PCM. (C) 2014 Published by Elsevier B.V.

Porous Ore Structure and Deposited Carbon Type during Integrated Pyrolysis-Tar Decomposition
Rochim B. Cahyono, Genki Saito, Naoto Yasuda, Takahiro Nomura, Tomohiro Akiyama
ENERGY & FUELS, 28, 3, 2129, 2134, AMER CHEMICAL SOC, Mar. 2014, [Peer-reviewed], [International Magazine]
English, Scientific journal, Carbon deposited by tar decomposition within pores of iron ore exhibited a high reactivity during the reduction reaction. The structure of porous low-grade ore was investigated in detail using transmission electron microscopy (TEM); a layered structure with 3 nm diameter pores was observed after dehydration, because of the removal of the hydroxide (OH) group from FeOOH. This pore size was deemed to be appropriate for tar decomposition and resultant carbon deposition. However, it was found that not all pores were filled with carbon. The TEM image showed that some of the deposited carbon partially blocks the pores, which negatively affects the carbon deposition process. In addition to the ore structure, the type of carbon deposited was also successfully evaluated using Raman spectroscopy and found to consist of two main peaks, G and D. The position of the G peak was found to shift slightly, indicating that the sp(3) content was reduced at elevated temperatures because of a greater degree of graphitization. The carbon deposited by integrated pyrolysis-tar decomposition over low-grade ore was categorized as amorphous carbon (a-C), with a sp(3) content of 19-21%. These results can also be explained by high reactivity of the deposited carbon, which was improved by not only nanoscale contact between iron and carbon but also specific molecule bonding and arrangement of amorphous carbon.

Optimum temperatures for carbon deposition during integrated coal pyrolysis-tar decomposition over low-grade iron ore for ironmaking applications
Rochim B. Cahyono, Naoto Yasuda, Takahiro Nomura, Tomohiro Akiyama
FUEL PROCESSING TECHNOLOGY, 119, 272, 277, ELSEVIER SCIENCE BV, Mar. 2014, [Peer-reviewed], [International Magazine]
English, Scientific journal, Deposited carbon within low-grade iron ore which was produced using integrated coal pyrolysis and tar decomposition showed high reactivity as a reducing agent. However, pyrolysis and tar decomposition were both highly sensitive to temperature and exhibited contrasting behaviors during carbon deposition. In these experiments, the optimum temperatures for pyrolysis and tar decomposition were determined to obtain maximum carbon deposition. High-temperature pyrolysis generated large amounts of volatile matter (tar and gases), which caused high tar decomposition and produced larger deposited carbon and gases. The deposited carbon was major product of tar decomposition at lower temperatures (400-600 degrees C), whereas mainly gases were produced at higher temperatures (700-800 degrees C), because of carbon gasification. The highest amount of deposited carbon was obtained at a pyrolysis temperature of 800 degrees C and a tar decomposition of 600 degrees C. Hamersley ore gave higher amounts of deposited carbon than Robe-river ore because of its large pore size of less than 4 nm, which was suitable for carbon deposition. The pore size distribution was a more important factor than the surface area. Based on these results, the proposed system could achieve maximum carbon deposition and solve problems related to reducing agents, tar materials, and the use of expensive materials in the ironmaking industry. (C) 2013 Elsevier B.V. All rights reserved.

Heat release performance of direct-contact heat exchanger with erythritol as phase change material
Takahiro Nomura, Masakatsu Tsubota, Teppei Oya, Noriyuki Okinaka, Tomohiro Akiyama
Applied Thermal Engineering, 61, 2, 28, 35, Nov. 2013, [Peer-reviewed], [Lead author], [International Magazine]
English, Scientific journal, This paper describes heat-release performance of a direct-contact heat exchanger using erythritol as a phase change material (PCM) along with a heat-transfer oil (HTO). A vertical cylinder with an inner diameter of 200 mm and a height of 1000 mm was used as a heat-storage unit (HSU). A nozzle with nine holes in diameter of 3.0 mm facing vertically downward was placed at the bottom of HSU. We examined the effects of flow rate of HTO and the height of PCM layer in the HSU, on three characteristic parameters of heat release - temperature effectiveness, heat release rate, and volumetric heat transfer coefficient. Consequently, we determined optimum conditions under which the HTO uniformly flowed in the PCM. When the HTO uniformly flow and the height of PCM was constant, the temperature effectiveness was high and the heat release rate was proportional to the flow rate of HTO. In addition, a high temperature effectiveness over 0.83 was observed even when the height of PCM was 0.2 m. Further, the average volumetric heat transfer coefficient increased with increasing the flow rate of HTO and decreasing the height of PCM. These results revealed that the direct-contact heat exchanger can rapidly, efficiently, and compactly release the latent heat of PCM provided that HTO uniformly flows. © 2013 Published by Elsevier Ltd.

Thermal conductivity enhancement of erythritol as PCM by using graphite and nickel particles
Teppei Oya, Takahiro Nomura, Masakatsu Tsubota, Noriyuki Okinaka, Tomohiro Akiyama
APPLIED THERMAL ENGINEERING, 61, 2, 825, 828, PERGAMON-ELSEVIER SCIENCE LTD, Nov. 2013, [Peer-reviewed], [International Magazine]
English, Scientific journal, We developed new phase change composites (PCC) using erythritol as a phase change material (PCM) and graphite and nickel particles as highly thermal conductive fillers. Their effective thermal conductivities became two orders of magnitude larger than that of the original PCM. The PCC was prepared by using a conventional dispersion technique and its effective thermal conductivity was measured by the laser flash method at room temperature. We interpreted the results based on percolation theory, for which the effects of the graphite structure and the volumetric ratio on the effective thermal conductivity were examined. The results showed that the effective thermal conductivity increased gradually with increasing filler content and aspect ratio of filler. Of significance, they increased remarkably when we used 20 vol% spherical graphite. Moreover, among the three samples that we prepared, the greatest thermal conductivity, 4.72 W(m K)(-1), was recorded for the PCC with 15 vol% expanded graphite content. This was 6.4 times higher than the thermal conductivity of pure erythritol. (C) 2012 Elsevier Ltd. All rights reserved.

Performance analysis of heat storage of direct-contact heat exchanger with phase-change material
Takahiro Nomura, Masakatsu Tsubota, Akihito Sagara, Noriyuki Okinaka, Tomohiro Akiyama
APPLIED THERMAL ENGINEERING, 58, 1-2, 108, 113, PERGAMON-ELSEVIER SCIENCE LTD, Sep. 2013, [Peer-reviewed], [International Magazine]
English, Scientific journal, This paper describes the improvement of the heat-storage performance of a direct-contact heat exchanger using the phase-change material (PCM) erythritol (melting point: 391 K) and a heat transfer oil (HTO). A vertical cylinder with 200-mm inner diameter and 1400-mm height was used as the heat-storage unit (HSU). A nozzle pointing vertically downwards was placed on the bottom of the HSU. We examined the effect of the height of the PCM in HSU on heat storage, using two characteristic parameters: temperature effectiveness and the rate of heat storage. According to the results, both of these parameters increase during the increase in latent heat storage with the height of PCM, due to the increase in the residence time with the height of PCM. (C) 2013 Elsevier Ltd. All rights reserved.

Catalytic coal-tar decomposition to enhance reactivity of low-grade iron ore
Rochim B. Cahyono, Alya N. Rozhan, Naoto Yasuda, Takahiro Nomura, Sou Hosokai, Yoshiaki Kashiwaya, Tomohiro Akiyama
FUEL PROCESSING TECHNOLOGY, 113, 84, 89, ELSEVIER SCIENCE BV, Sep. 2013, [Peer-reviewed], [International Magazine]
English, Scientific journal, Effective utilization of low-grade iron ore and coal can be one of the solutions for avoiding the high cost of raw materials and solving the problem of resource shortages in the steelmaking industry. This paper describes the behavior of reduction reaction during tar decomposition over low-grade iron ore. Pisolite ore, containing 5.9 mass% of combined water, was dehydrated at 450 degrees C to obtain porous ore. Tar vapor and pyrolysis gas of low-grade coal were introduced to porous ore for tar decomposition and carbon deposition. The iron ore effectively decomposed 22.1 mass% of tar component into gas product and deposited carbon at 600 degrees C. Besides tar decomposition, the ore was also reduced to magnetite and wustite by gas product which was produced from coal pyrolysis and tar decomposition. The reactivity of deposited carbon within ore was evaluated by reduction reaction using thermogravimetry method. The reduction of the carbon-deposited ore began at 750 degrees C, while that of the reference mixture. of Fe3O4 and coke began at 1100 degrees C. The carbon-deposited iron ore was more reactive because nanoscale contact between iron ore and carbon enhanced, reaction rate. These results revealed attractive utilization and reduction process of low-grade iron ore with coal tar decomposition. (C) 2013 Elsevier B.V. All rights reserved.

Integrated coal-pyrolysis tar reforming using steelmaking slag for carbon composite and hydrogen production
Rochim Bakti Cahyono, Alya Naili Rozhan, Naoto Yasuda, Takahiro Nomura, Sou Hosokai, Yoshiaki Kashiwaya, Tomohiro Akiyama
Fuel, 109, 439, 444, Elsevier Ltd, Jul. 2013, [Peer-reviewed], [International Magazine]
English, Scientific journal, Steelmaking slag contains high amounts of CaO, Fe2O3, SiO2, and Al2O3, and has great potential as a catalyst for the tar-reforming reaction to produce a carbon composite and hydrogen. This paper describes chemical waste-heat recovery of tar and the effects of slag on the tar-reforming reaction. The results indicate that slag has a good activity for decomposing tar into the gas phase and for producing high carbon content within the slag. The introduction of coal-pyrolysis products to slag at a temperature of 500°C caused an 18%vol increasing in the gas amount and a 6%mass enhancing in the carbon content within the slag compared to coal pyrolysis without slag. At higher temperatures, coal pyrolysis gave rise to lower carbon deposition within the slag but a higher amount of gas product. Moreover, the gas reforming reaction occurred simultaneously with tar decomposition at higher temperatures. This proposed system offers energy-saving benefits of 103 MJ/ton steel and a 6%mass reduction in coke-breeze usage in the steelmaking industry. © 2013 Elsevier Ltd. All rights reserved.

Carbon Deposition Using Various Solid Fuels for Ironmaking Applications
Rochim B. Cahyono, Alya N. Rozhan, Naoto Yasuda, Takahiro Nomura, Hadi Purwanto, Tomohiro Akiyama
ENERGY & FUELS, 27, 5, 2687, 2692, AMER CHEMICAL SOC, May 2013, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
English, Scientific journal, In this paper, we describe an innovative process involving iron reduction through chemical vapor deposition for applications in the ironmaking industry. In our experiment, we produced tar vapors from pyrolysis of various solid fuels, including high-grade bituminous coal (HGC), low-grade lignite coal (LGC), and biomass palm kernel shell (PKS), and decomposed these vapors into gases, carbon, and light hydrocarbon. Carbon was deposited within the pores of pisolite ore (low-grade ore), which became porous during the dehydration process at 450 degrees C. We determined that the amount of tar produced during pyrolysis strongly affected carbon deposition, and HGC produced the highest carbon deposition because of its large tar product. In addition to tar amount, surface area and pore volume also played important roles in this process. PKS had the highest ratio of deposited carbon because it produced the smallest quantities of reacted tar and, consequently, the largest numbers of vacant pores. The amount of carbon deposition decreased at higher temperatures because tar was easily converted to a gaseous phase. The deposited carbon within iron ore showed potential as a reducing agent because it was highly reactive and reduced at lower temperatures. Carbon deposited within iron pores dramatically reduced the contact distance between the iron ore and carbon. Thus, these results show that our proposed methodology could have important applications as an alternative low-energy approach for producing metallic iron using low-grade materials.

Heat storage in direct-contact heat exchanger with phase change material
Takahiro Nomura, Masakatsu Tsubota, Teppei Oya, Noriyuki Okinaka, Tomohiro Akiyama
Applied Thermal Engineering, 50, 1, 26, 34, Jan. 2013, [Peer-reviewed], [Lead author], [International Magazine]
English, International conference proceedings, This paper describes the development and performance of a direct-contact heat exchanger using erythritol (melting point: 391 K) as a phase change material (PCM) and a heat transfer oil (HTO) for accelerating heat storage. A vertical cylinder with 200-mm inner diameter and 1000-mm height was used as the heat storage unit (HSU). A nozzle facing vertically downward was placed at the bottom of the HSU. We examined the effects of flowrate and inlet temperature of the HTO using three characteristic parameters of heat storage - difference between inlet and outlet HTO temperatures, temperature effectiveness, and heat storage rate. The temperature history of latent heat storage (LHS) showed three stages: sensible heat of solid PCM, latent heat of PCM, and sensible heat of liquid PCM. Further, the operating mechanism of the DCHEX was proposed to explain the results. The average heat storage rate during LHS was proportional to the increase in flowrate and inlet temperature of HTO. Thus, latent heat can be rapidly stored under large HTO flowrate and high inlet temperature in the DCHEX. © 2012 Elsevier Ltd. All rights reserved.

Carbon Deposition from Biotar by Fast Pyrolysis Using the Chemical Vapor Infiltration Process within Porous Low-Grade Iron Ore for Iron-Making
Alya N. Rozhan, Rochim B. Cahyono, Naoto Yasuda, Takahiro Nomura, Sou Hosokai, Hadi Purwanto, Tomohiro Akiyama
ENERGY & FUELS, 26, 12, 7340, 7346, AMER CHEMICAL SOC, 07 Nov. 2012, [Peer-reviewed], ［Internationally co-authored］, [International Magazine]
English, Scientific journal, This paper presents a technology for iron-making using biomass and a low grade iron ore by implementing chemical vapor infiltration (CVI) for the tar carbonization process. In this process, tar vapor from pyrolysis of biomass was infiltrated within a porous ore and carbon deposition occurred on the pore surface. For preparation, ore sample was heated in an electric furnace to decompose combined water in the sample, creating nanosized pores. In the experiments, the traditional slow pyrolysis was compared with fast pyrolysis to determine which condition is better for maximizing carbon deposition. Tar vapor from the pyrolysis process was introduced into the porous ore and trapped inside it, where tar decomposed and carbonized within the pores. The product of this process which is a carbon-magnetite composite with close arrangement of iron ore and carbon is useful for reduction of iron by carbon and is able to lower the temperature needed for reduction of iron to occur, as compared to that in steelworks. The purpose of this research is to compare the effects of slow pyrolysis and fast pyrolysis processes on the amount of carbon deposited within iron ore by the tar carbonization process and to observe the reduction reactivity of the carbon-deposited iron ore.

Phase change composite based on porous nickel and erythritol
Teppei Oya, Takahiro Nomura, Noriyuki Okinaka, Tomohiro Akiyama
APPLIED THERMAL ENGINEERING, 40, 373, 377, PERGAMON-ELSEVIER SCIENCE LTD, Jul. 2012, [Peer-reviewed], [International Magazine]
English, Scientific journal, We developed a phase change composite (PCC) using a porous metal with a thermal conductivity that is two orders larger than that of the original phase change material (PCM). A PCC of erythritol/porous nickel was prepared by vacuum impregnation, and its thermophysical properties such as effective thermal conductivity, latent heat, and melting temperature were measured by the laser flash method and differential scanning calorimetry (DSC). The effect of the porous structure was also examined. Results showed that the latent heat of the PCC could be simply explained by the impregnation ratio of the PCM, not by the pore size. The largest effective thermal conductivity, 11.6W m(-1) K-1, was recorded for FCC with 15 vol% of porous nickel having a pore size of 500 pm and 85 vol% of PCM; this value is 16 times higher than that of pure erythritol, i.e., 0.733. The developed PCC offers many benefits, including a high heat transfer rate and enhanced cost-effectiveness, and it will also contribute to the efficient utilization of solar heat and industrial waste heat. (C) 2012 Elsevier Ltd. All rights reserved.

Carbon Deposition of Biotar from Pine Sawdust by Chemical Vapor Infiltration on Steelmaking Slag as a Supplementary Fuel in Steelworks
Alya N. Rozhan, Rochim B. Cahyono, Naoto Yasuda, Takahiro Nomura, Sou Hosokai, Tomohiro Akiyama
ENERGY & FUELS, 26, 6, 3196, 3200, AMER CHEMICAL SOC, 24 May 2012, [Peer-reviewed], [International Magazine]
English, Scientific journal, Steelmaking slag is an attractive material because it generally contains iron oxide and free lime, which makes it able to be regarded as flux-containing low-grade iron ore for steel production. In this study, tar vapor from the pyrolysis of pine sawdust was infiltrated within porous slag and carbon deposition occurred on the pore surface by chemical vapor infiltration. For preparation, the slag sample was dehydrated in an electric furnace to decompose hydrates in the sample, creating pores. Pine sawdust was charged from bowl feeder with flowing nitrogen gas into the reactor, where it was pyrolyzed at 500 degrees C, rapidly producing fuel gases, tar vapor, and char. Tar vapor was introduced into the dehydrated slag and trapped inside it, where tar decomposed and carbonized within the pores. The product distribution was analyzed after the experiment. Experiments were repeated by changing the temperature and time to obtain an optimum condition for this process. The purpose of this research is to examine the amount of carbon deposited within the steelmaking slag by this tar-carbonization process. The product of this process, which is carbon-containing slag, is useful for energy reduction in steelworks.

Technology of Latent Heat Storage for High Temperature Application: A Review
Takahiro Nomura, Noriyuki Okinaka, Tomohiro Akiyama
ISIJ INTERNATIONAL, 50, 9, 1229, 1239, IRON STEEL INST JAPAN KEIDANREN KAIKAN, 15 Sep. 2010, [Peer-reviewed], [Lead author, Corresponding author], [Domestic magazines]
English, Scientific journal, To save energy and reduce CO2 emissions, the utilization of solar energy and waste heat using latent heat storage (LHS) has emerged as an attractive solution because of advantages such as large density of heat storage, constant-temperature heat supply, and repeatable utilization without degradation. This review describes research trends in LHS technologies using phase-change materials (PCMs) based on papers published from 2001-2009, and state-of-the-art LHS technologies for high-temperature applications over 100 degrees C, such as solid solid PCM, encapsulation of PCMs, PCM composites, solar power generation with LHS, and waste heat recovery systems.

Feasibility of an Advanced Waste Heat Transportation System Using High-temperature Phase Change Material (PCM)
Takahiro Nomura, Teppei Oya, Noriyuki Okinaka, Tomohiro Akiyama
ISIJ INTERNATIONAL, 50, 9, 1326, 1332, IRON STEEL INST JAPAN KEIDANREN KAIKAN, 15 Sep. 2010, [Peer-reviewed], [Lead author, Corresponding author], [Domestic magazines]
English, Scientific journal, A waste-heat transportation (HT) system whose operation depends on the latent heat (LH) of high-temperature phase change material (PCM) is effective in reducing carbon dioxide (CO(2)) emission from industries. This paper describes 1) the use of the binary eutectic mixture NaOH/Na(2)CO(3) as a PCM to realize the HT system, 2) the feasibility of HT system using this PCM from viewpoints of energy requirements, exergy loss, and CO(2) emissions. In this study, we examined the thermophysical properties of the PCM and its chemical stability with reference to the heat transfer medium of the HT system by differential scanning calorimetry and thermogravimetry-differential thermal analysis. We observed that NaOH/Na(2)CO(3) had a LH of fusion of 252 kJ/kg and a melting point (MP) and a freezing point (FP) of 285+/-1 degrees C that was suitable for the HT system. There were no significant changes in the chemical and physical properties after aging for 500 h during phase change when dibenzyltoluene was used as the heat transfer medium. On the contrary, in the system analysis, the operating data in the proposed system-as well as in a conventional heat supply system-were calculated based on heat and material balances. The results show it has only 9.5% of the energy requirements, 39.7% of the exergy loss, and 19.6% of the CO(2) emissions of conventional systems that lack heat-recovery capabilities.

Waste heat transportation system, using phase change material (PCM) from steelworks to chemical plant
Takahiro Nomura, Noriyuki Okinaka, Tomohiro Akiyama
RESOURCES CONSERVATION AND RECYCLING, 54, 11, 1000, 1006, ELSEVIER SCIENCE BV, Sep. 2010, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
English, Scientific journal, This paper describes the feasibility of a latent heat transportation (LHT) system that uses phase change material (PCM) to recover waste heat at temperatures over 300 degrees C in steelworks and supplies it to a distillation tower of benzene, toluene, and xylene (BTX). The operating data in the proposed system as well as in a conventional heat supply system and a sensible heat transportation (SHT) system - were calculated based on heat and material balances in order to evaluate energy requirements, exergy loss, and CO(2) emissions. The results showed that an LHT system using NaOH with a solid-solid transformation temperature of 293 degrees C and a melting point of 320 degrees C as PCM has 2.76 times the amount of heat-storage density of an SHT system; additionally, it has only 8.6% of the energy requirements, 37.9% of the exergy loss, and 17.5% of the CO(2) emissions of a conventional system that lack heat-recovery capabilities. The results suggest the possibility of transporting heat via high-temperature PCM from steelworks to chemical plants. Such infrastructure would offer many benefits such as energy savings, reductions in exergy loss and CO(2) emissions, and the benefits associated with coproduction. (C) 2010 Elsevier B.V. All rights reserved.

Heat Transportation System From Steelworks to Chemical Plants
Takahiro Nomura, Noriyuki Okinaka, Tomohiro Akiyama
JOURNAL OF IRON AND STEEL RESEARCH INTERNATIONAL, 16, 1207, 1211, JOURNAL IRON STEEL RESEARCH EDITORIAL BOARD, Oct. 2009, [Peer-reviewed], [Lead author, Corresponding author]
English, International conference proceedings, This paper describes the feasibility of the latent heat transportation system using Phase Change Material (PCM) to recover waste heat at high temperature in the steelworks and to supply the recovered heat to chemical plants such as BTX plants. Candidates of PCM for the system were determined experimentally. Moreover, the proposed system was theoretically analyzed from three viewpoints-energy requirement, exergy loss and CO(2) emissions and compared to the conventional heat supply system and the sensible heat transportation system under reasonable assumptions. As a result, NaOH or its based materials were the best PCM candidates for the system from phase change point, latent heat and cost. The system analysis shows the latent heat transportation system using 17.1wt%Na(2)CO(3)-82.9wt%NaOH as PCM has 2.16 times larger in heat storage density than that in the sensible heat transportation system and compared to the conventional system without heat recovery, this system has only 7.6% in energy requirement, 31.4% in exergy loss and 16.3% in CO(2) emission. The results appealed a new possibility of heat transportation between different industries using PCM for high temperature application.

Impregnation of porous material with phase change material for thermal energy storage
Takahiro Nomura, Noriyuki Okinaka, Tomohiro Akiyama
MATERIALS CHEMISTRY AND PHYSICS, 115, 2-3, 846, 850, ELSEVIER SCIENCE SA, Jun. 2009, [Peer-reviewed], [Lead author, Corresponding author], [International Magazine]
English, Scientific journal, In order to efficiently recover waste heat in the form of latent heat, we studied the impregnation of a porous material with a phase change material (PCM); erythritol was selected as the PCM and expanded perlite (EP), diatom earth (DE), and gamma-alumina (CA) were selected as porous materials. Effects of vacuum in impregnation, pore size of porous materials, holding time and cyclic test on thermal properties of composites; latent heat, melting temperature, were mainly examined by using DSC. The following results were obtained. (1) The pores of EP were completely filled with liquid erythritol by the vacuum impregnation treatment, and the latent heat of the EP/erythritol composite reached 83% of the theoretical latent heat of pure erythritol (294.4 J g(-1)). (2) Porous materials with small pore sizes showed a low melting temperature for phase change composites. (3) The pores of EP were completely filled with erythritol at 1.8 ks immersion in the vacuum impregnation treatment. (4) EP/erythritol composite retained 75% of the impregnated PCM, even in a cyclic process of heating and cooling. In conclusion, the impregnation of porous material with erythritol is a promising method for conserving latent heat with high thermal storage density. (C) 2009 Elsevier B.V. All rights reserved.

Development of Al-Cu-Si alloy-based latent heat storage particles for utilization high temperature waste heat from steel making industry
清水友斗, 月足嶺, KURNIAWAN Ade, JEEM Melbert, 能村貴宏, 材料とプロセス(CD-ROM), 35, 2, 2022

Size effect on the crystalline and magnetic phases of Ca₂RuO₄
棚橋慧太, 延兼啓純, 坂口紀史, 迫田將仁, 丹田聡, 能村貴宏, 応用物理学会北海道支部/日本光学会北海道支部合同学術講演会講演予稿集, 56th-17th (CD-ROM), 2021

Modulation of lattice and magnetism by nanocrystallization of Ca₂RuO₄
棚橋慧太, 延兼啓純, 迫田將仁, 丹田聡, 能村貴宏, 応用物理学会秋季学術講演会講演予稿集(CD-ROM), 81st, 2020

Ferromagnetic phase emerged by controlling oxygen content in Ca₂RuO₄ nanocrystals
棚橋慧太, 能村貴宏, 延兼啓純, 迫田將仁, 丹田聡, 応用物理学会春季学術講演会講演予稿集(CD-ROM), 67th, 2020

Ca₂RuO₄の粒径と構造転移の関係性
棚橋慧太, 能村貴宏, 延兼啓純, 迫田將仁, 丹田聡, 秋山友宏, 応用物理学会秋季学術講演会講演予稿集(CD-ROM), 80th, 2019

層状ルテニウム酸化物ナノスケール結晶の輸送現象
礒野翔, 延兼啓純, 柳原興世, 小笠原優仁, 國貞雄治, 棚橋慧太, 能村貴宏, 秋山友宏, 秋山友宏, 野村一成, 丹田聡, 日本物理学会講演概要集(CD-ROM), 74, 2, 2019

ナノスケールCa₂RuO₄単結晶におけるBKT転移の観測
小笠原優仁, 柳原興世, 延兼啓純, 國貞雄治, 野村一成, 能村貴宏, 秋山友寛, 秋山友寛, 浅野泰寛, 丹田聡, 日本物理学会講演概要集(CD-ROM), 73, 1, ROMBUNNO.22aK503‐11, 23 Mar. 2018
Japanese

ルテニウム酸化物における超伝導-絶縁体転移と臨界指数
延兼啓純, 柳原興世, 國貞雄治, 小笠原優仁, 礒野翔, 野村一成, 能村貴宏, 秋山友宏, 秋山友宏, 浅野泰寛, 丹田聡, 日本物理学会講演概要集(CD-ROM), 73, 2, 2018

2次元Ca₂RuO₄における高温超伝導
延兼啓純, 柳原興世, 國貞雄治, 小笠原優仁, 野村一成, 能村貴宏, 秋山友宏, 秋山友宏, 浅野泰寛, 丹田聡, 日本物理学会講演概要集(CD-ROM), 72, 2, ROMBUNNO.24aF11‐2, 25 Sep. 2017
Japanese

Cooling Technology for Lithium-Ion Battery by Utilizing Phase Change Material and Heat Pipes
小野 直樹, 山田 崇, 秋山 友宏, 能村 貴宏, Material stage, 17, 6, 48, 51, Sep. 2017
技術情報協会, Japanese

Ca₂RuO₄ナノスケール単結晶における輸送現象
柳原興世, 延兼啓純, 野村一成, 能村貴宏, 秋山友宏, 丹田聡, 日本物理学会講演概要集(CD-ROM), 72, 1, ROMBUNNO.20aD32‐9, 21 Mar. 2017
Japanese

Development of micro-encapsulated phase change materialsusing al-based alloy for high temperature applications
Daiki Hanzaki, Takahiro Nomura, Nan Sheng, Tomohiro Akiyama, Journal of the Society of Powder Technology, Japan, 54, 1, 37, 40, 2017
This manuscript described the development of core-shell type micro-encapsulated phase change materials (MEPCM) using Al-based alloy as a phase change material (PCM) for high temperature applications. Al-25 mass% Si microspheres (diameter: 75~90 μm, melting temperature: 577°C) was used as core material (=PCM). The MEPCM was prepared in two steps. First step is the formation of AlOOH precursor shell on the PCM microspheres in boiling distilled water. Second step is heat-oxidation treatment in an O2 atmosphere to form a stable Al2O3 shell. The effects of heat-oxidation temperature (1150–1350°C) on the shell morphology and heat storage performance, were mainly investigated. As results, MEPCMs were successfully prepared and the shell compositions were single α-Al2O3 phase regardless of different heat oxidation temperature. The heat capacities of the as prepared MEPCMs were over 4 times higher than that of conventional heat storage materials. The MEPCM developed in this study has great promise in future energy utilization processes., Society of Powder Technology, Japanese

Exergy Analysis of Large-Scale Hydrogen Transportation using Several Types of Hydrogen Carriers
Koji Nakui, Takahiro Nomura, Tomohiro Akiyama, KAGAKU KOGAKU RONBUNSHU, 43, 1, 63, 73, 2017
A method to evaluate the efficiency of hydrogen transportation systems is proposed. Three major types of long-distance hydrogen carrier, organic chemical hydride, ammonia, and liquid hydrogen, are evaluated with the exergy efficiency as a criterion. In addition, exergy loss resulting from gas compression for road haulage is examined. Efficiency is expressed in terms of the ratio of net reserved exergy in the carrier to chemical exergy of hydrogen. The examined carriers would be normally expected to lose around 40 to 50% of exergy during modification processes (hydrogenation, dehydrogenation, and liquefaction) and to lose 2.5 to 10% during long-distance transportation. With the exergy consumption accruing from compression for local delivery and filling included, which comprise another 17% of losses, depending on the type of carrier, around half or more of the chemical exergy is found to be lost in the whole transportation system, based on the current technologies. In order for hydrogen to be an efficient medium as an energy carrier, it is necessary to recover unused exergy generated in the system, which would improve efficiency by 10% to more than 30%., SOC CHEMICAL ENG JAPAN, Japanese

Exergy Analysis of Large-Scale Hydrogen Transportation using Several Types of Hydrogen Carriers
Koji Nakui, Takahiro Nomura, Tomohiro Akiyama, KAGAKU KOGAKU RONBUNSHU, 43, 1, 63, 73, 2017
A method to evaluate the efficiency of hydrogen transportation systems is proposed. Three major types of long-distance hydrogen carrier, organic chemical hydride, ammonia, and liquid hydrogen, are evaluated with the exergy efficiency as a criterion. In addition, exergy loss resulting from gas compression for road haulage is examined. Efficiency is expressed in terms of the ratio of net reserved exergy in the carrier to chemical exergy of hydrogen. The examined carriers would be normally expected to lose around 40 to 50% of exergy during modification processes (hydrogenation, dehydrogenation, and liquefaction) and to lose 2.5 to 10% during long-distance transportation. With the exergy consumption accruing from compression for local delivery and filling included, which comprise another 17% of losses, depending on the type of carrier, around half or more of the chemical exergy is found to be lost in the whole transportation system, based on the current technologies. In order for hydrogen to be an efficient medium as an energy carrier, it is necessary to recover unused exergy generated in the system, which would improve efficiency by 10% to more than 30%., SOC CHEMICAL ENG JAPAN, Japanese

Development of micro-encapsulated phase change materialsusing al-based alloy for high temperature applications
Daiki Hanzaki, Takahiro Nomura, Nan Sheng, Tomohiro Akiyama, Journal of the Society of Powder Technology, Japan, 54, 1, 37, 40, 2017
This manuscript described the development of core-shell type micro-encapsulated phase change materials (MEPCM) using Al-based alloy as a phase change material (PCM) for high temperature applications. Al-25 mass% Si microspheres (diameter: 75~90 μm, melting temperature: 577°C) was used as core material (=PCM). The MEPCM was prepared in two steps. First step is the formation of AlOOH precursor shell on the PCM microspheres in boiling distilled water. Second step is heat-oxidation treatment in an O2 atmosphere to form a stable Al2O3 shell. The effects of heat-oxidation temperature (1150–1350°C) on the shell morphology and heat storage performance, were mainly investigated. As results, MEPCMs were successfully prepared and the shell compositions were single α-Al2O3 phase regardless of different heat oxidation temperature. The heat capacities of the as prepared MEPCMs were over 4 times higher than that of conventional heat storage materials. The MEPCM developed in this study has great promise in future energy utilization processes., Society of Powder Technology, Japanese

水素還元したラテライト鉱石の触媒性能
阿部圭佑, KURNIAWAN Ade, 能村貴宏, 秋山友宏, 材料とプロセス(CD-ROM), 29, 2, ROMBUNNO.31, 01 Sep. 2016
Japanese

放熱から蓄熱材料分野へも拡がるサーマルマネージメント材料 高熱伝導性潜熱蓄熱材料の開発状況
能村貴宏, 秋山友宏, 機能材料, 36, 8, 5‐15, 05 Aug. 2016
Japanese

高温用Al合金系潜熱蓄熱マイクロカプセルの開発
能村貴宏, 盛楠, 半崎大揮, 秋山友宏, 粉体工学会研究発表会講演論文集, 2016, 148‐149, 17 May 2016
Japanese

500°C級高温鉄鋼排熱回収のための潜熱蓄熱マイクロカプセル
能村貴宏, 盛楠, 半崎大揮, 秋山友宏, 材料とプロセス(CD-ROM), 29, 1, ROMBUNNO.104, 01 Mar. 2016
Japanese

Ni含有低品位鉄鉱石の触媒利用
阿部圭佑, 齊藤元貴, 能村貴宏, 秋山友宏, 材料とプロセス(CD-ROM), 29, 1, ROMBUNNO.PS‐32, 01 Mar. 2016
Japanese

高温用PCMマイクロカプセルの蓄熱性能
能村貴宏, 半崎大揮, NAN Sheng, 秋山友宏, 日本伝熱シンポジウム講演論文集(CD-ROM), 53rd, ROMBUNNO.H111, 2016
Japanese

潜熱蓄熱熱交換器における熱交換速度改善
能村貴宏, 阿部圭祐, 半崎大揮, 丸岡伸洋, 埜上洋, 秋山友宏, 東北大学多元物質科学研究所研究発表会講演予稿集, 16th, 80, 2016
Japanese

メタンの二酸化炭素改質反応におけるNi含有多孔質鉄鉱石の触媒特性
阿部圭佑, 能村貴宏, 秋山友宏, 日本鉄鋼協会日本金属学会両支部合同冬季講演大会概要集, 2015, 15, 17 Dec. 2015
Japanese

Ni含有多孔質鉄鉱石の触媒特性
阿部圭佑, 能村貴宏, 秋山友宏, 化学工学会秋季大会研究発表講演要旨集(CD-ROM), 47th, ROMBUNNO.V206, 09 Sep. 2015
Japanese

Al基合金系PCMマイクロカプセル生成条件の検討
能村貴宏, 朱春宇, 盛楠, 深堀諒, 秋山友宏, 化学工学会秋季大会研究発表講演要旨集(CD-ROM), 47th, ROMBUNNO.M308, 09 Sep. 2015
Japanese

高温蓄熱システムのための合金PCMカプセルの開発
深堀諒, 能村貴宏, 朱春宇, 沖中憲之, 秋山友宏, 化学工学会秋季大会研究発表講演要旨集(CD-ROM), 47th, ROMBUNNO.ZA2P32, 09 Sep. 2015
Japanese

高温用潜熱蓄熱・熱輸送粒子の開発
能村貴宏, ZHU Chunyu, SHENG Nan, 半崎大揮, 秋山友宏, 日本エネルギー学会大会講演要旨集, 24th, 196, 197, 27 Jul. 2015
Japanese

次世代太陽熱発電のための合金PCMカプセル化技術
深堀諒, 能村貴宏, ZHU Chunyu, SHENG Nan, 沖中憲之, 秋山友宏, 日本エネルギー学会大会講演要旨集, 24th, 168, 169, 27 Jul. 2015
Japanese

低温未利用熱回収のための共晶系糖アルコール潜熱蓄熱材の開発
半崎大揮, 能村貴宏, ZHU Chunyu, 秋山友宏, 日本エネルギー学会大会講演要旨集, 24th, 170, 171, 27 Jul. 2015
Japanese

4-1-3 Encapsulation of metallic phase change material (PCM) for advanced concentrating solar power
FUKAHORI Ryo, NOMURA Takahiro, ZHU Chunyu, SHENG Nan, OKINAKA Noriyuki, AKIYAMA Tomohiro, 日本エネルギー学会大会講演要旨集, 24, 24, 168, 169, 27 Jul. 2015
This study reports 1) their corrosion effects to ceramic materials, 2) thermal analysis of Al-Si alloys as candidates of high-temperature (over 500℃) phase change material (PCM), and 3) new encapsulation technique for the PCM. Four Al-Si alloys were selected as the PCM. Engineering ceramics such as Al_2O_3, AlN, Si_3N_4, SiC, and SiO_2 were used for corrosion tests. The corrosion tests revealed that Al_2O_3, AlN, and Si_3N_4 shows high corrosion resistance to molten Al-Si alloys, therefore, they were suitable as structural materials for latent heat storage systems (LHS) using Al-Si alloys. Results of thermal analysis shows the ADC12 and Al-25wt%Si were promising PCM due to their large latent heat. Mushroom-like Al_2O_3 capsules were applied to the new encapsulation technique. In addition, the prepared PCM capsule showed good durability. These results indicated the feasibility of a high temperature LHS using Al-Si alloys and ceramics., 一般社団法人日本エネルギー学会, Japanese

4-1-4 Development of Eutectic Sugar Alcohol as Phase Change Material for Recovery of Low-Temperature Unused Heat
HANZAKI Daiki, NOMURA Takahiro, ZHU Chunyu, AKIYAMA Tomohiro, 日本エネルギー学会大会講演要旨集, 24, 24, 170, 171, 27 Jul. 2015
This paper reports 1) thermal analysis of sugar alcohol as candidates of low-temperature (80〜200 ℃) phase change material (PCM), and 2) investigation of phase diagrams of new eutectic sugar alcohol PCMs by calculation and measurement. From the thermal analysis, Threitol, Erythritol, Mannitol and Dulcitol were classified as good PCM candidates. As results of the investigation of phase diagrams, we found eutectic sugar alcohols such as Threitol-Erythritol, Erythritol-Mannitol and Mannitol-Dulcitol. The three eutectic mixtures had new operation temperature compared to single component sugar alcohol PCMs. The calculation values corresponded to those of measurement. The developed PCMs are promising for recovery of low-temperature unused heat such as solar heat., 一般社団法人日本エネルギー学会, Japanese

6-1-1 Development of High-temperature Latent Heat Storage/Transportation Particle
NOMURA Takahiro, ZHU Chunyu, Nan Sheng, HANZAKI Daiki, AKIYAMA Tomohiro, 日本エネルギー学会大会講演要旨集, 24, 24, 196, 197, 27 Jul. 2015
We developed a core-shell type microencapsulated phase change material (MEPCM) which has high storage density for high temperature (> 500 ℃) applications. Al-Si alloy with melting temperature of 577 ℃ was selected as a PCM. The MEPCM was prepared in two steps: (1) the formation of an AlOOH shell on the PCM particles using a boehmite treatment, and (2) heat-oxidation treatment in an O_2 atmosphere to form a stable α-Al_2O_3 shell. As results, the MEPCM covered with dense α-Al_2O_3 shells were successfully prepared and it presented a melting point of 573 ℃, latent heat of 247 J g^<-1>, and good cyclic performance. These results indicated the possibility of using MEPCM at high temperatures. The MEPCM developed in this study has great promise in future energy and chemical processes, such as exergy recuperation and process intensification., 一般社団法人日本エネルギー学会, Japanese

高温用PCMマイクロカプセルの開発
NOMURA TAKAHIRO, SHU SHUNU, MORI YUZURU, AKIYAMA TOMOHIRO, 化学工学会年会研究発表講演要旨集(CD-ROM), 80th, ROMBUNNO.L318, 19 Mar. 2015
Japanese

鉄鋼排熱有効利用のための高温潜熱蓄熱材料の開発
深堀諒, 能村貴宏, 秋山友宏, 材料とプロセス(CD-ROM), 28, 1, ROMBUNNO.DAI169KAI,PS-21, 01 Mar. 2015
Japanese

ホットプレス法による高熱伝導性相変化複合材料の開発
田渕一希, 能村貴宏, ZHU Chunyu, 秋山友宏, 日本伝熱シンポジウム講演論文集(CD-ROM), 52nd, ROMBUNNO.SP109, 2015
Japanese

糖アルコール系相変化物質のガラス転移現象を応用した潜熱蓄熱法
能村貴宏, 田渕一希, ZHU Chunyu, 沖中憲之, 秋山友宏, 日本伝熱シンポジウム講演論文集(CD-ROM), 52nd, ROMBUNNO.C131, 2015
Japanese

YSZ固体電解質を用いたCO₂電解における電極構造の変化と交流インピーダンス法による解析
SHIOMI YOHEI, KASHIWAYA YOSHIAKI, HASEGAWA MASAKATSU, NOMURA TAKAHIRO, AKIYAMA TOMOHIRO, 材料とプロセス(CD-ROM), 27, 2, ROMBUNNO.145, 01 Sep. 2014
Japanese

Al基合金系相変化物質の蓄熱性能
NOMURA TAKAHIRO, SAGARA AKIHITO, ZHU CHUNYU, OKINAKA NORIYUKI, AKIYAMA TOMOHIRO, 日本伝熱シンポジウム講演論文集(CD-ROM), 51st, ROMBUNNO.G124, 2014
Japanese

合金系PCMマイクロカプセルの開発
NOMURA TAKAHIRO, SHU SHUNU, SEI NAN, OKINAKA NORIYUKI, AKIYAMA TOMOHIRO, 化学工学会秋季大会研究発表講演要旨集(CD-ROM), 46th, ROMBUNNO.N306, 2014
Japanese

アンモニア分解に対するゲーサイト鉱石の触媒特性
YASUDA NAOTO, CAHYONO ROCHIM BAKTI, NOMURA TAKAHIRO, AKIYAMA TOMOHIRO, 材料とプロセス(CD-ROM), 26, 2, ROMBUNNO.123, 01 Sep. 2013
Japanese

液体燃焼合成製酸素吸蔵物質Ca₂AlMnO₅の酸素吸脱蔵特性
NOMURA TAKAHIRO, SHU SHUNU, AKIYAMA TOMOHIRO, 材料とプロセス(CD-ROM), 26, 2, ROMBUNNO.126, 01 Sep. 2013
Japanese

融点降下による糖アルコール系潜熱蓄熱材の長寿命化
SAGARA AKIHITO, NOMURA TAKAHIRO, OKINAKA NORIYUKI, AKIYAMA TOMOHIRO, 化学工学会秋季大会研究発表講演要旨集(CD-ROM), 45th, ROMBUNNO.V215, 16 Aug. 2013
Japanese

Technology of Latent Heat Storage for Utilization of Unused Heat
能村 貴宏, 秋山 友宏, 化學工業, 64, 5, 358, 367, May 2013
小峰工業出版, Japanese

先端素材の新たなステージ 未利用熱有効利用のための潜熱蓄熱技術
NOMURA TAKAHIRO, AKIYAMA TOMOHIRO, 化学工業, 64, 5, 358, 367, 01 May 2013
Japanese

低温廃熱回収用潜熱蓄熱複合体
SAGARA AKIHITO, NOMURA TAKAHIRO, TSUBOTA MASATOSHI, OKINAKA NORIYUKI, AKIYAMA TOMOHIRO, 材料とプロセス(CD-ROM), 26, 1, ROMBUNNO.PS-28, 01 Mar. 2013
Japanese

アンモニアによるヘマタイトの還元および窒化挙動
YASUDA NAOTO, NOMURA TAKAHIRO, CAHYONO ROCHIM B, MOCHIZUKI YUKI, TSUBOUCHI NAOTO, AKIYAMA TOMOHIRO, 化学工学会年会研究発表講演要旨集(CD-ROM), 78th, ROMBUNNO.P124, 17 Feb. 2013
Japanese

メソ多孔質体への含浸処理による潜熱蓄熱材の熱安定性改善
SAGARA AKIHITO, NOMURA TAKAHIRO, OKINAKA NORIYUKI, AKIYAMA TOMOHIRO, 日本伝熱シンポジウム講演論文集(CD-ROM), 50th, ROMBUNNO.SP38, 2013
Japanese

低温鉄鋼廃熱回収用直接接触式潜熱蓄熱装置の設計
NOMURA TAKAHIRO, TSUBOTA MASATOSHI, OKINAKA NORIYUKI, AKIYAMA TOMOHIRO, 材料とプロセス(CD-ROM), 25, 2, ROMBUNNO.167, 01 Sep. 2012
Japanese

廃熱と低品位鉱石を利用するCVI製鉄の可能性
NOMURA TAKAHIRO, YASUDA NAOTO, CAHYONO ROCHIM BAKTI, PURWANTO HADI, KASHIWAYA YOSHIAKI, AKIYAMA TOMOHIRO, 材料とプロセス(CD-ROM), 25, 2, ROMBUNNO.TO29, 01 Sep. 2012
Japanese

アンモニア濃度がヘマタイト還元に及ぼす影響
YASUDA NAOTO, NOMURA TAKAHIRO, CAHYNO ROCHIM BAKTI, ROZHAN ALYA NAILI, AKIYAMA TOMOHIRO, HOSOKAI SO, 材料とプロセス(CD-ROM), 25, 2, ROMBUNNO.162, 01 Sep. 2012
Japanese

直接接触式熱交換法を用いた潜熱蓄熱装置の性能特性
NOMURA TAKAHIRO, TSUBOTA MASANORI, OKINAKA NORIYUKI, AKIYAMA TOMOHIRO, 化学工学会秋季大会研究発表講演要旨集(CD-ROM), 44th, ROMBUNNO.M123, 19 Aug. 2012
Japanese

直接接触式潜熱蓄熱装置の放熱性能改善
NOMURA TAKAHIRO, TSUBOTA MASAKATSU, OYA TEPPEI, OKINAKA NORIYUKI, AKIYAMA TOMOHIRO, 日本伝熱シンポジウム講演論文集(CD-ROM), 49th, ROMBUNNO.I311, 2012
Japanese

ニッケル多孔体,グラファイトによる潜熱蓄熱材料の高熱伝導化
OYA TEPPEI, NOMURA TAKAHIRO, OKINAKA NORIYUKI, AKIYAMA TOMOHIRO, 日本金属学会講演概要(CD-ROM), 149th, ROMBUNNO.POSUTASESSHON,380, 20 Oct. 2011
Japanese

低温鉄鋼廃熱回収用直接接触式潜熱蓄熱装置の放熱特性
NOMURA TAKAHIRO, TSUBOTA MASATOSHI, OYA TEPPEI, OKINAKA NORIYUKI, AKIYAMA TOMOHIRO, 材料とプロセス(CD-ROM), 24, 2, ROMBUNNO.188, 01 Sep. 2011
Japanese

直接接触式潜熱蓄熱装置の熱交換特性
NOMURA TAKAHIRO, TSUBOTA MASATOSHI, OYA TEPPEI, OKINAKA NORIYUKI, AKIYAMA TOMOHIRO, 材料とプロセス(CD-ROM), 24, 1, ROMBUNNO.142, 01 Mar. 2011
Japanese

Heat Storage/Release in Direct-Contact Heat Exchanger for Latent Heat Storage
Nomura Takahiro, Tsubota Masakatsu, Oya Teppei, Okinaka Noriyuki, Akiyama Tomohiro, Proceedings of National Heat Transfer Symposium, 2011, 0, 108, 108, 2011
相変化物質（PCM；Phase Change Material）を利用して廃熱を貯蔵，輸送，供給する潜熱蓄熱輸送システムは大幅な省エネが達成可能であり，実用化が進んでいる。本研究の目的はPCM（エリスリトール，融点118˚C）と熱媒油との直接接触式熱交換における各種操業条件（熱媒油流量，熱媒油温度，PCM層高）が蓄放熱特性に及ぼす影響調査である。その結果は，従来を上回る熱交換速度の達成，蓄放熱時間短縮によるシステム全体の高効率化を示唆した。本研究は，新エネルギー・産業技術総合開発機構平成20～22年度委託業務「環境調和型製鉄プロセス技術開発」による。, The Heat Transfer Society of Japan, Japanese

低温廃熱利用型氷輸送システムの可能性調査
NOMURA TAKAHIRO, OYA TEPPEI, OKINAKA NORIYUKI, AKIYAMA TOMOHIRO, 材料とプロセス(CD-ROM), 23, 2, ROMBUNNO.175, 01 Sep. 2010
Japanese

多孔質金属による高熱伝導性潜熱蓄熱コンポジットの開発
OYA TEPPEI, NOMURA TAKAHIRO, OKINAKA NORIYUKI, AKIYAMA TOMOHIRO, 日本金属学会講演概要, 146th, 324, 28 Mar. 2010
Japanese

高熱伝導性潜熱蓄熱コンポジットの開発
OYA TEPPEI, NOMURA TAKAHIRO, OKINAKA NORIYUKI, AKIYAMA TOMOHIRO, 材料とプロセス(CD-ROM), 23, 1, ROMBUNNO.PS-72, 01 Mar. 2010
Japanese

Development of Phase Change Composite with Large Thermal Conductivity by Impregnation method
Oya Teppei, Nomura Takahiro, Okinaka Noriyuki, Akiyama Tomohiro, Proceedings of National Heat Transfer Symposium, 2010, 0, 133, 133, 2010
廃熱回収法としてPCM (Phase Change Material)の固液相変態時の潜熱を利用する潜熱蓄熱法は高密度熱貯蔵の観点から魅力的である。しかし、PCMの熱伝導率が低く蓄放熱応答性が悪いのは問題である。そこで本研究では多孔質金属中へPCMを含浸することで、形状安定かつ高熱伝導性PCMコンポジットの開発を試みた。, The Heat Transfer Society of Japan, Japanese

Recent Utilization Technology of Unused Waste Heat: Recent Advance in Technology of Latent Heat Storage
NOMURA TAKAHIRO, OKINAKA NORIYUKI, AKIYAMA TOMOHIRO, J Jpn Inst Energy, 88, 11, 950, 960, 20 Nov. 2009
Japanese

Recent Advance in Technology of Latent Heat Storage(Recent Utilization Technology of Unused Waste Heat)
NOMURA Takahiro, OKINAKA Noriyuki, AKIYAMA Tomohiro, Journal of the Japan Institute of Energy, 88, 11, 950, 960, 20 Nov. 2009
Latent heat storage using phase change material (PCM) is an important technology to save energy and reduce CO_2 emissions. PCM is very effective for utilizing solar energy and waste heat from three viewpoints of large thermal storage density, energy conversion of intermittently-supplied thermal energy into constant temperature heat source and repeatable utilization. Thus, this paper introduces the recent advance on technology of latent heat storage, based on 542 papers collected from major database., 一般社団法人日本エネルギー学会, Japanese

Recent advance in technology of latent heat storage
Takahiro Nomura, Noriyuki Okinaka, Tomohiro Akiyama, Nihon Enerugi Gakkaishi/Journal of the Japan Institute of Energy, 88, 950, 960, 01 Nov. 2009
Latent heat storage using phase change material (PCM) is an important technology to save energy and reduce CO2 emissions. PCM is very effective for utilizing solar energy and waste heat from three viewpoints of large thermal storage density, energy conversion of intermittently-supplied thermal energy into constant temperature heat source and repeatable utilization. Thus, this paper introduces the recent advance on technology of latent heat storage, based on 542 papers collected from major database.

6-3-3 Coproduction System of Steel and Chemicals Using Latent-Heat Transportation
Nomura Takahiro, Okinaka Noriyuki, Akiyama Tomohiro, 日本エネルギー学会大会講演要旨集, 18, 18, 350, 351, 30 Jul. 2009
This paper describes the feasibility of the latent heat transportation system using Phase Change Material (PCM) to recover waste heat at high temperature over 300℃ in the steelworks and to supply it to distillation tower of BTX. Candidates of PCM for the system were determined experimentally. Moreover, the proposed system was theoretically analyzed from three viewpoints-energy requirement, exergy loss and CO_2 emissions and compared to the conventional heat supply system under reasonable assumptions. As a result, binary eutectic mixtures of NaOH-Na_2CO_3 was the best PCM candidate for the system from phase change point, latent heat and cost. The system analysis shows comparing the latent heat transportation system using binary eutectic mixtures of NaOH-Na_2CO_3 as PCM with the conventional system without heat recovery, the proposed system has only 8.6% in energy requirement, 37.5% in exergy loss and 19.7% in CO_2 emission. The results appealed a new possibility of heat transportation between different industries using PCM for high temperature application., 一般社団法人日本エネルギー学会, Japanese

潜熱蓄熱輸送による鉄鋼・化学コプロダクションの可能性調査
NOMURA TAKAHIRO, OKINAKA NORIYUKI, AKIYAMA TOMOHIRO, 日本エネルギー学会大会講演要旨集, 18th, 350, 351, 30 Jul. 2009
Japanese

Latent Heat Storage and Transportation System Using Erythritol
NOMURA TAKAHIRO, KAIZAWA AKIHIDE, KAMANO HIROOMI, KAWAI ATSUSHI, JOZUKA TETSUJI, SENDA TAKESHI, OKINAKA NORIYUKI, AKIYAMA TOMOHIRO, 日本伝熱シンポジウム講演論文集(CD-ROM), 46th, 0, ROMBUNNO.G-1303, 126, 2009
相変化物質（PCM；Phase Change Material）の融解、凝固を利用して工業廃熱を民生に輸送供給する潜熱蓄熱輸送システムは大幅な省エネが期待できる。本研究では、PCMとしてエリスリトールを使用した潜熱蓄熱コンテナ内部の熱流動解析および総合システム評価を行った。その結果、伝熱速度促進のための潜熱蓄熱コンテナの設計、操作条件の最適化を達成するとともに、潜熱蓄熱輸送システムは既存の化石燃料燃焼型の熱供給システムと比較して投入エネルギー量、エクセルギー損失量、CO<SUB>2</SUB>排出量を大幅に削減可能であることを定量的に明らかにした。, 社団法人 日本伝熱学会, Japanese

潜熱蓄熱材の含浸処理
NOMURA TAKAHIRO, OKINAKA NORIYUKI, AKIYAMA TOMOHIRO, 材料とプロセス(CD-ROM), 21, 2, ROMBUNNO.PS-57, 01 Sep. 2008
Japanese

潜熱蓄熱による鉄鋼・化学コプロダクションの可能性調査
NOMURA TAKAHIRO, OKINAKA NORIYUKI, AKIYAMA TOMOHIRO, NAGASAKA TETSUYA, 材料とプロセス(CD-ROM), 21, 2, ROMBUNNO.386, 01 Sep. 2008
Japanese

Ca2RuO4の粒径と構造転移の関係性　　　　　　　　　　　　　　　
棚橋 慧太, 能村 貴宏, 延兼 啓純, 迫田 將仁, 丹田 聡, 秋山 友宏
応用物理学会秋季学術講演会, 19 Sep. 2019, Poster presentation
[Domestic Conference]

未利用熱有効利用のためのZn-Al合金相変化マイクロカプセル　　　　　　　　　　　　　　　
川口貴大, 樫山康平, 長俊介, 坂井浩紀, 盛楠, 秋山友宏, 能村貴宏
日本鉄鋼協会 第178回秋季講演大会, 12 Sep. 2019, Poster presentation
[Domestic Conference]

CO2メタネーションの温度制御に向けたNi担持相変化マイクロカプセルの表面改質　　　　　　　　　　　　　　　
高橋達也, 小出浩明, 坂井浩紀, 盛楠、Ade Kurniawan, 秋山友宏, 能村貴宏
日本鉄鋼協会 第178回秋季講演大会, 12 Sep. 2019, Poster presentation
[Domestic Conference]

Pt粉末添加による酸素吸蔵材料Ca2AlMnO5の吸蔵特性改善　　　　　　　　　　　　　　　
佐藤亜由夢, 阿部圭祐, 齊藤元貴, 能村貴宏, 秋山友宏
令和元年度鉄鋼協会北海道支部サマーセッション, 05 Jul. 2019, Poster presentation
[Domestic Conference]

潜熱/化学蓄熱機能を有するハイブリッド材料の開発　　　　　　　　　　　　　　　
小出浩明, 高橋達也, 坂井浩紀, 能村貴宏, 秋山友宏
日本鉄鋼協会日本金属学会両支部合同サマーセッション, 05 Jul. 2019
[Domestic Conference]

マイクロカプセルPCMを用いた反応熱制御技術の検討　　　　　　　　　　　　　　　
能村貴宏, SHENG Nan, 坂井浩紀, 高橋達也, 秋山友宏
第56回 日本伝熱シンポジウム, 31 May 2019
[Domestic Conference]

潜熱蓄熱マイクロカプセルを主原料とした蓄熱ペレットの作製　　　　　　　　　　　　　　　
坂井浩紀, 芳賀美紀, 長谷川裕太, 盛楠, 秋山友宏, 能村貴宏
日本鉄鋼協会 第177回春季講演大会, 20 Mar. 2019
[Domestic Conference]

熱・化学・CO2ルーピングによるエネルギーレス酸素置換/CO2回収システムの開発
科学研究費助成事業
01 Apr. 2022 - 31 Mar. 2026
能村 貴宏, 國貞 雄治, 坂口 紀史
日本学術振興会, 基盤研究(A), 北海道大学, 22H00306

Development of Fluidized Bed Heat Storage Unit with PCM particles that can rapidly store and release heart and Biomass Power Generation Systems
Grants-in-Aid for Scientific Research
01 Apr. 2022 - 31 Mar. 2025
伏見 千尋, 能村 貴宏, 池上 貴志
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Tokyo University of Agriculture and Technology, 22K04815

Development of exergy recuperating type oxygen production device with a micro-scale reaction heat circulation mechanism.
Grants-in-Aid for Scientific Research
01 Apr. 2019 - 31 Mar. 2022
Nomura Takahiro
Converting from air to pure oxygen utilization technology is essential for energy conservation and CO2 emission reduction in industrial sector. However, oxygen production by cryogenic distillation method is an excessively energy-consuming process. Therefore, an advanced O2 production process is required. Therefore, this study focused on the pressure swing adsorption method as an energy-saving oxygen production process, and aimed to develop an oxygen production device with a micro-scale reaction heat circulation mechanism. As a result, we succeeded in synthesizing a new oxygen storage material without hysteresis during oxygen adsorption and desorption. We also developed a reaction heat control device consisting of an oxygen storage material and a latent heat storage material, and confirmed the reaction heat control and circulation functions during oxygen absorption and desorption.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 19H02653

Nano-microscale catalytic reaction heat control technology based on heat storage engineering
Grants-in-Aid for Scientific Research
28 Jun. 2019 - 31 Mar. 2021
Nomura Takahiro
The purpose of this study was to develop a reaction heat control device in which catalyst/carrier/micro-encapsulated phase change material are integrated and contact on a nano/micro scale. As the basis of development, we investigated a technology for supporting or coating the catalyst itself or a material in which a catalyst carrier composed of a catalyst or a complex oxide is integrated and contact on the shell surface of MEPCM. Although various reaction systems were considered, the materials were adjusted and their characteristics were evaluated by targeting the CO2 methanation reaction, which is attracting attention as an effective use technology for CO2. As a result, we succeeded in developing devices such as Ni-supported phase change microcapsules. In addition, it was observed that the developed devices can absorb the reaction heat of CO2 methanation.
Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Research (Exploratory), Hokkaido University, 19K22224

Development of next-generation latent heat stoarge and transportation technology for high temperature applications
Grants-in-Aid for Scientific Research
01 Apr. 2015 - 31 Mar. 2019
Nomura Takahiro
Purpose of this study is to develop a next-generation high-temperature heat storage and transportation technology, based on a latent heat storage using phase change material (PCM) which can store and release a large amount of thermal energy at a constant temperature. Especially, a latent heat storage medium (=microencapsulated PCM) with a high-heat storage density, high-speed heat response, and high-temperature operation was mainly developed. As the results of this project, microencapsulated PCM with various operating temperature ranges were developed by using various Al based PCMs. In addition, bulk heat storage media such as pellets and mm size particles, and microencapsulated PCM with catalyst were successfully developed.
Japan Society for the Promotion of Science, Grant-in-Aid for Young Scientists (A), Hokkaido University, 15H05567

development of third-generation latent heat storage technology utilizing the glass transition
Grants-in-Aid for Scientific Research
01 Apr. 2014 - 31 Mar. 2016
Nomura Takahiro, AKIYAMA Tomohiro
Latent heat storage technology, which utilizes latent heat during solid-liquid phase transition of a phase change material (PCM), can realize a high heat storage capacity and supply heat at a constant temperature. Therefore, this method is suitable for waste heat recovery and solar energy utilization. However a conventional latent heat storage technology cannot realize a long-term heat storage. In addition, an encapsulation technology is needed to avoid a leakage of liquid PCM during heat storage. Therefore, this study proposed third-generation latent heat storage technology utilizing the glass transition to achieve for super long term heat storage and capsule free heat transportation. As results, we investigated a noble glass-transition sugar-alcohol PCM which can be applied the proposed concept. In addition, we designed new heat transportation processes which can achieve the proposed concept.
Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, Hokkaido University, 26630491

合金系潜熱蓄熱材を用いた高温未利用熱の有効活用
科学研究費助成事業
30 Aug. 2013 - 31 Mar. 2015
能村 貴宏
本研年度は、500度超に融点を持つAl-Si系合金PCMの開発を目的とした。具体的には、①Al-Si系合金の熱物性調査、②Al-Si系合金と代表的耐熱材料との腐食性試験を実施した。
①Al-Si系合金の熱物性調査：Siは融解時の体積膨張率が負（-9.6%）のため、合金元素として添加することで、PCM候補材の融解時体積膨張率を低く制御可能であり、PCMとしての実用上極めて有利となる。そこで、本研究ではAl-12wt%Si、Al-17wt%Si、Al-20wt%Si、Al-25wt%Si、Al-30wt%SiをPCM候補として、その蓄熱性能を測定した。その結果、共晶組成近傍のAl-12wt%Siの潜熱量は0.5 MJ/kgであり、PCMとして極めて有望であった。また、過共晶組成であるAl-25wt%SiとAl-30wt%Siの蓄熱量可能量500度から800度の範囲で測定したところ、1MJ/kg以上の値を示した。過共晶領域では、温度の降下と共に連続的にSiの初晶が析出するため、この結晶化潜熱が液相、固相の比熱に上乗せされ、見掛け上大きな比熱として観察される。従来のPCMは液体比熱が小さく、融点または共晶点付近での蓄熱のみに温度範囲が限定されていた。一方、過共晶領域にまで組成範囲を広げることで、より広い温度範囲で効率的に高密度蓄熱が可能となることが明らかとなった。
②Al-Si系合金と代表的耐熱材料の腐食性試験：Al-Si系合金SiとAl2O3、SiCとの腐食性を、真空雰囲気下で、1000度の合金溶湯中に、試験片を100h浸漬することで評価した。Al-Si系合金PCM候補として、Al-25wt%Siの他にAC9A、ADC12等の規格合金も検討した。その結果、Al2O3は検討した合金PCM候補に対して腐食されず、PCM用の構造材として極めて有望であった。
日本学術振興会, 研究活動スタート支援, 北海道大学, 25889002

蓄熱体
Patent right, 秋山 友宏, 沖中 憲之, 能村 貴宏, 国立大学法人北海道大学
特願2013-540793, 24 Oct. 2012
特許第6057184号
16 Dec. 2016
201703012087824817

高炉送風方法及び高炉送風設備
Patent right, 村井 亮太, 小川 直孝, 松野 英寿, 秋山 友宏, 能村 貴宏, JFEスチール株式会社
特願2015-071451, 31 Mar. 2015
特開2016-191110, 10 Nov. 2016
201603014567666990

蓄熱材の使用・保存方法および蓄熱・熱供給システム
Patent right, 秋山 友宏, 能村 貴宏, 相良 昭人, 沖中 憲之, 朱 春宇, JSR株式会社, 国立大学法人北海道大学
特願2014-200098, 30 Sep. 2014
特開2016-069510, 09 May 2016
201603006904387222

金属含有ナノ粒子の製造方法
Patent right, 秋山 友宏, 朱 春宇, 齊藤 元貴, 能村 貴宏, 中津川 勲, 中田 成, 国立大学法人北海道大学, 株式会社燃焼合成
特願2014-087652, 21 Apr. 2014
特開2015-207469, 19 Nov. 2015
201503012461687433

潜熱蓄熱体、潜熱蓄熱体の製造方法、および、熱交換材料
Patent right, 秋山 友宏, 能村 貴宏, 相良 昭人, 沖中 憲之, 朱 春宇, 国立大学法人北海道大学
JP2015002204, 23 Apr. 2015
WO2015-162929, 29 Oct. 2015
201703015401892570

蓄熱体
Patent right, 秋山 友宏, 沖中 憲之, 能村 貴宏, 国立大学法人北海道大学
JP2012077395, 24 Oct. 2012
WO2013-061978, 02 May 2013
201503029377492790