Yasuda Keita

写真a

Title

Associate Professor

Researcher Number(JSPS Kakenhi)

60760163

Date of Birth

1984

Laboratory Address

1 Senbaru,Nishihara,Okinawa

Mail Address

E-mail address

Laboratory Phone number

+81-98-895-8613
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Current Affiliation Organization 【 display / non-display 】

  • Duty   University of the Ryukyus   Faculty of Engineering   School of Engineering_Energy and Environment Program   Associate Professor  

  • Charge of Lecture   University of the Ryukyus   Graduate School of Engineering and Science   Thermal and Fluid Engineering   Associate Professor  

  • Charge of Lecture   University of the Ryukyus   Graduate School of Engineering and Science   Material,Structural and Energy Engineering   Associate Professor  

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University 【 display / non-display 】

  • 2003.04
    -
    2007.03

    Keio University   Faculty of Science and Engineering   Department of Mechanical Engineering   Graduated

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Graduate School 【 display / non-display 】

  • 2007.04
    -
    2009.03

    Keio University  Graduate School, Division of Science and Engineering  School of Science for Open and Environmental Systems  Master's Course  Completed

  • 2009.04
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    2015.03

    Keio University  Graduate School, Division of Science and Engineering  School of Science for Open and Environmental Systems  Doctor's Course  Completed

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Academic degree 【 display / non-display 】

  • Keio University -  Ph.D. in Engineering

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External Career 【 display / non-display 】

  • 2009.04
    -
    2010.03

     

  • 2010.04
    -
    2012.03

     

  • 2010.05
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    2010.10

    Visiting Scholar in Colorado School of Mines  

  • 2015.04
    -
    2017.03

    University of the Ryukyus, Faculty of Engineering, Department of Mechanical Systems Engineering, Instructor  

  • 2017.04
    -
    2022.05

    University of the Ryukyus, Faculty of Engineering, School of Engineering, Energy and Environment Program, Instructor  

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Research Interests 【 display / non-display 】

  • Physical Chemistry and Engineering of Clathrate Hydrates

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Research Areas 【 display / non-display 】

  • Manufacturing Technology (Mechanical Engineering, Electrical and Electronic Engineering, Chemical Engineering) / Thermal engineering

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Thesis 【 display / non-display 】

  • 氷点下温度域におけるクラスレートハイドレートの相平衡条件と結晶構造

    2015.03

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Published Papers 【 display / non-display 】

  • Eutectic crystallization of cyclopentane clathrate hydrate and calcium sulfate: Implications for seawater desalination

    Yuta Agatsuma, Mion Orita, Yukari Sukegawa, Kouki Mekaru, Rinnosuke Tamaki, Ryo Ohmura, Keita Yasuda

    Journal of Environmental Chemical Engineering ( Elsevier )  13 ( 5 ) 118029   2025.10 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

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    The eutectic crystallization of cyclopentane clathrate hydrate and solid calcium sulfate was performed to reduce the amount of calcium sulfate in concentrated seawater for the development of seawater desalination and salt production technology. The experiments were performed in terms of eutectic conditions and dynamics of eutectic crystallization. From the eutectic condition measurements, it was found that the eutectic temperature is 280.1 K, and the eutectic concentration corresponds to a mass fraction of 0.002 of calcium sulfate. In the eutectic crystallization experiments, the remaining unreacted solution was analyzed. An increase in the water-to-hydrate conversion ratio led to an increase in the reduction ratio of calcium sulfate; it was found that an average water-to-hydrate conversion ratio of 14 % yielded an average reduction ratio of calcium sulfate of 18 %. Based on these results, a conceptual design for a methodology was presented combining reverse osmosis, multi-stage clathrate hydrate-based seawater desalination, multi-stage clathrate hydrate-based seawater desalination with calcium sulfate reduction, and clathrate hydrate-based seawater desalination and salt production.

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  • Eutectic conditions of carbon dioxide clathrate hydrate and sodium Chloride: Implications for zero liquid discharge seawater desalination

    Akari Gibo, Seiya Nakao, Ryo Ohmura, Keita Yasuda

    Journal of Industrial and Engineering Chemistry ( Elsevier )  147   512 - 521   2025.07 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

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    The eutectic temperature, pressure, and concentration conditions of carbon dioxide clathrate hydrate and sodium chloride dihydrate were measured to advance clathrate hydrate-based seawater desalination and salt production technology that enables seawater desalination through zero liquid discharge. The measured eutectic conditions were within the temperature range of 256.2 K ≤ Teu ≤ 263.5 K, the pressure range of 0.91 MPa ≤ peu ≤ 2.70 MPa, and the concentration range, expressed as the mass fraction of sodium chloride, of 0.235 ≤ wm,eu ≤ 0.242. These eutectic conditions correspond to the four-phase equilibrium of a saturated sodium chloride aqueous solution, carbon dioxide clathrate hydrate, carbon dioxide gas, and sodium chloride dihydrate, as well as the five-phase equilibrium of a saturated sodium chloride aqueous solution, carbon dioxide clathrate hydrate, carbon dioxide gas, liquid carbon dioxide, and sodium chloride dihydrate. Based on the measured eutectic conditions, implications for implementing clathrate hydrate-based seawater desalination and salt production were presented, including a conceptual design for a methodology involving reverse osmosis, multi-stage clathrate hydrate-based seawater desalination, and clathrate hydrate-based seawater desalination and salt production.

  • Thermophysical Properties of Clathrate Hydrates with Various Guests for Novel Technologies: A Review

    Keita Yasuda, Ryo Ohmura

    International Journal of Thermophysics ( Springer Nature )  45   139   2024.10 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

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    Thermophysical properties relevant to clathrate hydrate-based technologies were reviewed. Clathrate hydrates are solids composed of water and guests. The clathrate hydrate-based technologies considered in this study were as follows: carbon capture, utilization, and sequestration; natural gas storage and transportation; ozone storage and transportation; carbon dioxide clathrate hydrate as food; desalination and salt production; separation of tritiated water; cold thermal energy storage; and heat pumps and heat engines. The review was based on the experimentally measured data. The reviewed thermophysical properties were phase equilibrium conditions, formation/decomposition enthalpy, heat capacity, thermal conductivity, interfacial tension, and density. The phase equilibrium conditions determine the operating conditions for the clathrate hydrate-based technologies. The formation/decomposition enthalpy, heat capacity, and thermal conductivity relate to the thermal energy exchange during hydrate formation/decomposition. The interfacial tension is a key parameter when considering the multiphase flow composed of water and guests. The density influences the behavior of clathrate hydrates within the reactor. The relevance between these properties and the clathrate hydrate-based technologies was discussed. The methods correlating the phase equilibrium conditions were also compared in terms of applicability and usefulness. It was revealed that the suitability of the model, which is based on the Clausius–Clapeyron equation or statistical thermodynamic modeling, depends on the purpose of the correlation. Future perspectives of the thermophysical properties of clathrate hydrates were also discussed.

  • Carbon Dioxide Clathrate Hydrate Formation and Mass Balance Calculation: A Laboratory Experiment

    Keita Yasuda, Izuru Senaha

    Journal of Chemical Education ( ACS Publications )  101   3969 - 3974   2024.09 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

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    Clathrate hydrates are attractive materials for education because they form from water and familiar compounds, such as carbon dioxide, and are relevant to novel technologies. In this study, an attempt to propose a laboratory experiment was summarized, which used carbon dioxide clathrate hydrate as an educational material with carbon capture technologies as the background of the experiment. The experiment was provided from October 2020 to August 2022 in the “Laboratory Experiments in Energy and Environment Engineering” class for second- and third-year undergraduate students. A total of 90 students, divided into 14 groups and 28 subgroups, performed the experiment. The carbon dioxide clathrate hydrate was formed under low-temperature and high-pressure conditions. Based on the measured temperature and pressure conditions, the amount of formed carbon dioxide clathrate hydrate was calculated as exercise problems. In addition to the exercise problems, the students submitted a report describing the experiments and related discussions. 92% of the students passed the required score to earn the credit for the class. The average score for those who passed the class was 84%. The educational effect was discussed based on the content of the exercise problems and reports. A stirring device to enhance the clathrate hydrate formation was designed and constructed by two students enrolled in “Project Management Practice” for fourth-year undergraduate students. They obtained a 100% score because they successfully constructed the device based on a project management method. The device was used in a laboratory experiment.

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  • Mist cooling lithium–ion battery thermal management system for hybrid electric vehicles

    Aoto Teranishi, Takuma Kurogi, Izuru Senaha, Shoichi Matsuda, Keita Yasuda

    Applied Energy ( Elservier )  364   123214   2024.06 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

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    Battery Thermal Management System (BTSM) is essential for maintaining optimal operation conditions for hybrid electric vehicles (HEVs) and electric vehicles (EVs). This study aimed to propose an innovative impinging jet cooling BTMS for HEVs using mist cooling. The dilute mist completely evaporated to avoid the risk of external circuit failure or corrosion that could result from surface wetting. Impinging experiments were performed under the conditions where inflow air temperature, Ta,in, was 21.2 ◦C ≤ Ta,in ≤ 31.0 ◦C and initial humidity, φ, was 50.9 %RH ≤ φ ≤ 96.0 %RH. It was found that the target plate was cooled down by up to 0.8 K without surface wetting by adding 5.5 mg/s water mist to the air. Numerical analyses were performed under conditions ranging from 21.2 ◦C ≤ Ta,in ≤ 31.0 ◦C and 0.0 %RH ≤ φ ≤ 100.0 %RH. The results and discussion highlight the importance of the critical initial humidity, φcritical: the complete evaporative threshold. Deviation between the experimental and numerical results at a fixed inflow air temperature, Δφ, was 1.9 %RH ≤ Δφ ≤ 3.0 %RH. Δφ was within the range of measurement uncertainty U(φ) = 4.0 %RH. Thus, the experimental and numerical results were consistent within the experimental measurement uncertainty. As a result, φcritical tends to be high in the case of high inflow temperature. The mist cooling is a viable way of BTMS for HEVs without surface wetting due to its large cooling capacity that results in a 7.4 K cooling effect in a hot environment.

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Other Papers 【 display / non-display 】

  • Phase Equilibrium Conditions in Carbon Dioxide + Cyclopentane Double Clathrate Hydrate Forming System for Development of Seawater Desalination Technology

    Hideya Suzuki, Kouki Mekaru, Takuto Miyagi, Ayaka Mishima, Isami Uehara, Keita Yasuda

    2024 6th International Conference on Resources and Environmental Research     XG6002-A   2024.12  [Refereed]

     

  • Phase Equilibrium Condition Measurements for Dual-Functional Technology of Clathrate Hydrate-Based Seawater Desalination and Carbon Capture

    Toshikazu Sasaki, Kouki Mekaru, Toru Kubonaka, Shosei Morizumi, Keita Yasuda

    2024 6th International Conference on Resources and Environmental Research     XG6004-A   2024.12  [Refereed]

     

  • Interfacial Tension Measurements in Carbon Dioxide and Seawater System: An Implication for Clathrate Hydrate-Based Seawater Desalination

    Shun Tsunekawa, Suzuna Yamaguchi, Kazuma Ishikawa, Ayushman Tripathi, Keita Yasuda

    2024 6th International Conference on Resources and Environmental Research     XG6003-A   2024.12  [Refereed]

     

  • Phase Equilibrium Conditions in Cyclopentane Clathrate Hydrate Forming Systems Coexisting with Sodium Chloride Aqueous Solutions

    Toshikazu Sasaki, Keitatsu Kamochi, Ayushman Tripathi, Masanao Taoka, Ryo Ohmura, Keita Yasuda

    The 12th International Conference on Separation Science and Technology     109   2023.11  [Refereed]

     

  • Relative Density of Carbon Dioxide Clathrate Hydrate and Sodium Chloride Aqueous Solution: Implications for Desalination Processes

    Shun Tsunekawa, Akari Gibo, Toshiyuki Tanaka, Sayaka Shiraishi, Ryo Ohmura, Keita Yasuda

    The 12th International Conference on Separation Science and Technology     109   2023.11  [Refereed]

     

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SDGs 【 display / non-display 】

  • クラスレートハイドレートの物理化学とエンジニアリング

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