安田 啓太 (ヤスダ ケイタ)

Yasuda Keita

写真a

職名

准教授

科研費研究者番号

60760163

生年

1984年

研究室住所

〒903-0213 沖縄県中頭郡西原町字千原1番地

メールアドレス

メールアドレス

研究室電話

098-895-8613

ホームページ

https://w3.u-ryukyu.ac.jp/kyasuda/

現在の所属組織 【 表示 / 非表示

  • 専任   琉球大学   工学部   工学科エネルギー環境工学コース   准教授  

出身大学 【 表示 / 非表示

  • 2003年04月
    -
    2007年03月

    慶應義塾大学   理工学部   機械工学科   卒業

出身大学院 【 表示 / 非表示

  • 2007年04月
    -
    2009年03月

    慶應義塾大学  理工学研究科  開放環境科学専攻  修士課程  修了

  • 2009年04月
    -
    2015年03月

    慶應義塾大学  理工学研究科  開放環境科学専攻  博士課程  修了

取得学位 【 表示 / 非表示

  • 慶應義塾大学 -  博士(工学)  熱工学

職歴 【 表示 / 非表示

  • 2009年04月
    -
    2010年03月

      慶應義塾大学研究員(有期・文部科学省グローバルCOEプログラム「環境共生・安全システムデザインの先導拠点」)  

  • 2010年04月
    -
    2012年03月

      日本学術振興会 特別研究員(DC2)  

  • 2010年05月
    -
    2010年10月

      米国コロラド鉱業大学客員研究員  

  • 2015年04月
    -
    2017年03月

      琉球大学 工学部 機械システム工学科 助教  

  • 2017年04月
    -
    2022年05月

      琉球大学 工学部 工学科 エネルギー環境工学コース 助教  

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所属学会・委員会 【 表示 / 非表示

  • 2021年09月
    -
    継続中
     

    一般社団法人 日本機械学会

研究キーワード 【 表示 / 非表示

  • 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

研究分野 【 表示 / 非表示

  • ものづくり技術(機械・電気電子・化学工学) / 熱工学

学位論文 【 表示 / 非表示

  • 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年03月 

論文 【 表示 / 非表示

  • Phase Equilibrium Conditions in Cyclopentane Hydrate Forming Systems Coexisting with Sodium Chloride Aqueous Solution under Atmospheric Pressure and Vacuum Condition

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

    The Journal of Chemical Thermodynamics ( Elsevier )  175   106886   2022年12月 [ 査読有り ]

    掲載種別: 研究論文(学術雑誌)

    関連する研究費コード: 19K14911, 22K03948

     概要を見る

    The equilibrium condition measurements were performed in the cyclopentane clathrate hydrate forming systems coexisting with sodium chloride as a technological basis for the development of seawater desalination technology using clathrate hydrates. The experiments were performed in the system under vacuum condition in addition to the system under atmospheric pressure. The equilibrium conditions in the system under the vacuum condition are essential to accurately construct the phase diagram in the cyclopentane clathrate hydrate forming system without the effects of the surrounding air. The equilibrated phases were sodium chloride aqueous solution + cyclopentane clathrate hydrate + liquid cyclopentane + vapor cyclopentane in the system under the vacuum condition. The concentration of sodium chloride investigated in this study, wNaCl, was 0 ≤ wNaCl ≤ 0.210 in mass fraction. The equilibrium temperature in both systems decreased with increasing wNaCl. The equilibrium temperature at a fixed concentration of sodium chloride under the vacuum condition was lower than that under the atmospheric pressure. It was attributed to the compression by the atmospheric pressure in addition to the incorporation of molecules constituting the atmospheric air.

  • Development of Dual Functional Methodology for Seawater Desalination and Salt Manufacture by Carbon Dioxide Hydrate Formation

    Akari Gibo, Seiya Nakao, Sayaka Shiraishi, Satoshi Takeya, Shigeo Tomura, Ryo Ohmura, Keita Yasuda

    Desalination ( Elsevier )  539   115937   2022年10月 [ 査読有り ]

    掲載種別: 研究論文(学術雑誌)

    関連する研究費コード: 19K14911, 22K03948

     概要を見る

    Clathrate-hydrate-based seawater desalination is a novel technology that is performed by reaction between seawater and guest compounds to obtain fresh water. This study proposed a dual functional methodology for seawater desalination and salt manufacture by using carbon dioxide clathrate hydrate. In this methodology, the clathrate hydrate formation continues until the concentration of electrolytes in unreacted brine reaches the saturated solubility for the salt precipitation. The visual observation of the clathrate hydrate formation and the salt precipitation coupled with the analysis utilizing the powder X-ray diffraction (PXRD) technique was implemented to demonstrate the methodology. The carbon dioxide clathrate hydrate formation was first performed with sodium chloride aqueous solution. The carbon dioxide clathrate hydrate crystals floated on high salinity water. This experiment was followed by the occurrence of the sodium chloride dihydrate precipitation upon the carbon dioxide clathrate hydrate formation. The formed compounds, carbon dioxide clathrate hydrate and sodium chloride dihydrate, were identified by PXRD analysis. The mass fraction of the compounds was also determined by PXRD.

  • Visual Observation of Tetra-n-butylammonium Bromide Ionic Semiclathrate Hydrate Formation: A Laboratory Experiment

    Keita Yasuda

    Journal of Chemical Education ( American Chemical Society )  98   3587 - 3592   2021年11月 [ 査読有り ]

    掲載種別: 研究論文(学術雑誌)

     概要を見る

    A laboratory experiment was performed using tetra-n-butylammonium bromide (TBAB) ionic semiclathrate hydrate, a crystalline compound. Ionic semiclathrate hydrates have unique properties, and hence, novel technologies utilizing the ionic semiclathrate hydrates have been proposed to date. Thus, students could learn fundamentals of functional materials through ionic semiclathrate hydrates from chemical and engineering points of view. In the experiment, formation of the TBAB hydrate was observed at fixed temperature and under atmospheric pressure by using TBAB aqueous solutions having TBAB mass fractions of wTBAB = 0.10, 0.20, 0.30, 0.40, and 0.50. There are no serious safety hazards. In addition, the experiment can be performed using inexpensive equipment and materials. The amount of the formed TBAB hydrate and its crystal morphology depended on the concentration of the aqueous solution. The students needed to submit a laboratory report describing fundamentals of the ionic semiclathrate hydrates, a relationship between equilibrium conditions and the amount of the formed TBAB hydrate, and an adequate crystal morphology of the TBAB hydrate crystals as a thermal storage material. Most students understood the experiment well, and the average score of the reports was approximately 80%.

  • Simultaneous Crystallization of Cyclopentane Hydrate and Sodium Chloride for Desalination and Salt Manufacture

    Mikihiro Tanaka, Keita Tsugane, Daiki Suga, Shigeo Tomura, Ryo Ohmura, Keita Yasuda

    ACS Sustainable Chemistry & Engineering ( American Chemical Society )  9   9078 - 9084   2021年07月 [ 査読有り ]

    掲載種別: 研究論文(学術雑誌)

    関連する研究費コード: 19K14911

     概要を見る

    Simultaneous crystallization of cyclopentane hydrate and sodium chloride dihydrate was implemented to demonstrate a dual-functional system for hydrate-based seawater desalination and salt manufacture that could be performed with zero emission. A sodium chloride aqueous solution having an initial mass fraction of sodium chloride of 0.235 or 0.264 was used for the experiments as an alternative to seawater. When using the aqueous solution having a sodium chloride concentration of 0.264 in mass fraction, the precipitation of polyhedral sodium chloride dihydrate crystals was first observed, followed by the formation of particulate cyclopentane hydrate crystals. In contrast, when using the aqueous solution having a sodium chloride concentration of 0.235 in mass fraction, the formation of particulate cyclopentane hydrate was first observed and then the particulate sodium chloride dihydrate precipitated. The formed cyclopentane hydrate and the precipitated sodium chloride dihydrate were separated by the remaining sodium chloride aqueous solution due to the density difference even after the agitation of the system. The eutectic temperature and concentration were determined to be 259.75 K and 0.238 in mass fraction of sodium chloride, respectively.

  • Phase Equilibrium Condition Measurements in Carbon Dioxide Hydrate Forming System Coexisting with Seawater

    Rihito Nakane, Yusuke Shimosato, Eito Gima, Ryo Ohmura, Izuru Senaha, Keita Yasuda

    The Journal of Chemical Thermodynamics ( Elsevier )  152   106276   2021年01月 [ 査読有り ]

    掲載種別: 研究論文(学術雑誌)

    関連する研究費コード: 17K14604

     概要を見る

    Three phase equilibrium conditions of synthetic standard (seawater + carbon dioxide hydrate + carbon dioxide gas) were experimentally determined based on the batch, isochoric procedure. The total mass fraction of the electrolytes in the synthetic standard seawater, wss, was 0.0351, 0.0700, or 0.1036 that was composed of pure water and seven salts. The equilibrium pressure–temperature conditions were as follows: 271.95 K < T < 279.05 K and 1.298 MPa < p < 3.144 MPa in the system having wss = 0.0351, 272.25 K < T < 278.15 K and 1.530 MPa < p < 3.361 MPa in the wss = 0.0700 system and 271.15 K < T < 275.65 K and 1.643 MPa < p < 2.909 MPa in the wss = 0.1036 system. The quantitative evaluation of the changes in the equilibrium temperature at a fixed pressure was performed by applying the equilibrium conditions to the Clausius–Clapeyron equation. The results are essential to design the thermodynamic conditions for the clathrate hydrate-based seawater desalination technology.

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  • 微小微量ミストを付加した衝突噴流熱伝達の流速依存性

    伊敷 和樹,安田 啓太

    沖縄化学装置懇話会 令和3年度沖縄学生発表会     2022年02月  [査読有り]

     

  • シクロペンタンハイドレート生成にともなう硫酸カルシウム二水和物の析出

    助川 祐香利,安田 啓太

    沖縄化学装置懇話会 令和3年度沖縄学生発表会     2022年02月  [査読有り]

     

  • 二酸化炭素ハイドレート生成系の相平衡条件と浮沈条件

    白石 清花,安田 啓太

    沖縄化学装置懇話会 令和3年度沖縄学生発表会     2022年02月  [査読有り]

     

  • シクロペンタンと二酸化炭素のダブルハイドレート生成系の高濃度塩化ナトリウム共存下での相平衡条件測定

    三嶋 彩佳,安田 啓太

    沖縄化学装置懇話会 令和3年度沖縄学生発表会     2022年02月  [査読有り]

     

  • 学生実験としてのTBABハイドレートの成長観察

    安田 啓太

    日本機械学会 技術と社会部門 講演会     2021年11月  [査読有り]

     

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  • 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