KEIO RESEARCHERS INFORMATION SYSTEM

Career 【 Display / hide 】

Career 【 Display / hide 】

• 1999.04

  -

  2000.03

  JSPS Research Fellow (DC1)

• 2000.04

  -

  2002.03

  JSPS Research Fellow (PD)

• 2002.04

  -

  2006.03

  Research Scientist, AIST

• 2006.04

  -

  Present

  Assistant Professor

• 2009.04

  -

  Present

  慶應義塾大学准教授

Academic Background 【 Display / hide 】

Academic Background 【 Display / hide 】

• 1996.03

  Keio University, Faculty of Science and Technology, Dapartment of Mechanical Engineering

  University, Graduated

• 2000.03

  Keio University, －, 機械工学専攻

  Graduate School, Completed, Doctoral course

Academic Degrees 【 Display / hide 】

Academic Degrees 【 Display / hide 】

• Ph. D., Keio University, Coursework, 2000.03

Research Areas 【 Display / hide 】

Research Areas 【 Display / hide 】

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

• Nanotechnology/Materials / Fundamental physical chemistry (Physical Chemistry)

Research Keywords 【 Display / hide 】

Research Keywords 【 Display / hide 】

• Energy

• Clathrate Hydrates

• Physical Chemistry

• Environment

• Crystal Growth

Research Themes 【 Display / hide 】

Research Themes 【 Display / hide 】

• Physical Chemistry in Clathrate Hydrate Forming Systems, 

  1996

  -

  Present

Papers 【 Display / hide 】

Papers 【 Display / hide 】

• Hydrate-based continuous hydrogen gas separation from mixing gas containing carbon dioxide with cyclopentanone

  Kamiya L., Kasai R., Takeya S., Ohmura R.

  International Journal of Hydrogen Energy 121   111 - 117 2025.04

  ISSN  03603199

  　View Summary

  Clathrate-hydrate-based H2 separation is superior to conventional separation methods in terms of energy consumption, but the criteria for selecting promoters that facilitate stable hydrate formation and gas separation are unclear. We conducted continuous and batch separation experiments in a CO2 + H2 + cyclopentanone (CP-one) system and powder X-ray diffraction (PXRD) measurements of the hydrate formed in this system. While the mole fraction of H2 in the gas phase increased from 0.60 to 0.90 in continuous separation, CO2 in the hydrate phase remained at 0.90. PXRD measurements revealed that CO2 + H2 + cyclopentanone hydrate possesses the structure II hydrate, suggesting CO2 and CP-one encapsulation in small and large cages of hydrate. Compared to previous studies using tetrahydropyran and cyclopentane as guest compounds, CP-one with high water solubility facilitated kinetics of the hydrate, encapsulation of CO2 in the hydrate and more stable separation. This study would provide a comprehensive understanding of selecting guest compounds for hydrate-based separation.

  • Access to Document (DOI)

• Interfacial tension between water and pentane saturated with methane

  Yamashita T., Iwai T., Alavi S., Ohmura R.

  Colloids and Surfaces A: Physicochemical and Engineering Aspects 710 2025.04

  ISSN  09277757

  　View Summary

  The plugging of natural gas pipelines caused by hydrate formation has been recognized as a problem in the oil and gas industry for approximately 90 years. Interfacial tension is an important physical property to understand the dynamics of multiphase flow, namely, natural gas, condensate, and water, inside the pipelines. This paper describes our measurements of the interfacial tension between water and pentane saturated with methane as a model for the fluids in the pipelines transporting gas and condensate. The measurements were conducted by the pendant drop method in the temperature range between 278.2 K and 293.2 K, and the methane pressure range between 1.1 MPa and 13.7 MPa. The uncertainty of the measurements is typically below 1.5 mN∙m−1. The interfacial tension decreased with increasing temperature at 2 MPa. As for the pressure dependence at 288.2 K, with increasing pressure, the interfacial tension decreased from 49.12 mN∙m−1 at 1.1 MPa to 47.64 mN∙m−1 at 4.0 MPa. The interfacial tension remained roughly constant until 8.7 MPa with the value being 48.02 mN∙m−1 and then increased to 59.81 mN∙m−1 at 12.9 MPa. The decrease of the interfacial tension between 1.1 MPa and 4.0 MPa could be attributed to the increase of the methane molecule adsorption at the interface. In the pressure range between 4.0 MPa and 8.7 MPa, it is likely that the methane adsorption at the water – pentane interface became saturated. The increase of the interfacial tension above 8.7 MPa is a novel phenomenon which requires further investigation.

  • Access to Document (DOI)

• Demonstration of a Practical Cooling Storage System for Lithium-Ion Batteries with Trimethylolethane (TME) Hydrate for EV

  Kamiya L., Koyama R., Arai Y., Ohmura R.

  Energies 18 ( 6 )  2025.03

  　View Summary

  Lithium-ion batteries are required to equip the cooling system for high power performance, quick charge, and safety. Trimethylolethane (TME) hydrate is known as phase change material (PCM), a cooling medium that offers large dissociation heat and 30 °C form/dissociation temperature under atmospheric pressure. This study demonstrates the design of a practical cooling system with TME hydrate. This cooling method involves cooling outdoor air through water contact, exchanging heat between the cooled outdoor air and the aqueous solution of TME hydrate, exchanging heat from the resulting TME hydrate with a refrigerant, and finally supplying the processed refrigerant to the cooling LIB. Koyama et al. conducted a study on the physical properties of TME hydrate. They measured equilibrium temperatures and dissociation heats of TME mass fractions from 0.20 to 0.80. Their findings revealed that at a mass fraction of 0.60, the system reached its highest equilibrium temperature of 29.6 °C, and the dissociation heat peaked at 190.1 kJ/kg. This cooling system employed TME hydrate. These results underscore the potential of TME hydrates in energy-efficient cooling systems and demonstrate that they are suitable for lithium-ion battery cooling systems.

  • Access to Document (DOI)

• Phase Equilibrium of CO<inf>2</inf> Hydrate with Rubidium Chloride Aqueous Solution

  Kasai R., Kamiya L., Ohmura R.

  Separations 12 ( 1 )  2025.01

  　View Summary

  Salt lakes are a rich source of metals used in various fields. Rubidium is found in small amounts in salt lakes, but extraction technology on an industrial scale has not been developed completely. Clathrate hydrates are crystalline compounds formed by the encapsulation of guest molecules in cage-like structures made of water molecules. One of the most important properties for engineering practices of hydrate-based technologies is the comprehension of the phase equilibrium conditions. Phase equilibrium conditions of CO2 hydrate in rubidium chloride aqueous solution with mass fractions of 0.05, 0.10, 0.15 and 0.20 were experimentally investigated in the pressure range from 1.27 MPa to 3.53 MPa, and the temperature was from 268.7 K to 280.6 K. The measured equilibrium temperature in this study decreased roughly in proportion to the concentration of the RbCl solution from the pure water system. This depression is due to the lowering of the chemical potential of water in the liquid phase by the dissolution of RbCl. Experimental results compared with other salt solution + CO2 hydrate systems showed that the equilibrium temperatures decreased to a similar degree for similar mole fractions.

  • Access to Document (DOI)

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

  Gibo A., Nakao S., Ohmura R., Yasuda K.

  Journal of Industrial and Engineering Chemistry  2025

  ISSN  1226086X

  　View Summary

  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.

  • Access to Document (DOI)

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Papers, etc., Registered in KOARA 【 Display / hide 】

Papers, etc., Registered in KOARA 【 Display / hide 】

• Development of efficient, environment-friendly CO2 capture technology using clathrate hydrate

  Omura, Ryo

  科学研究費補助金研究成果報告書 2015

• Possibility of carbon dioxide hydrate as a extinguishing agent agait large scale fire

  Omura, Ryo

  科学研究費補助金研究成果報告書 2013

• Crystal growth of clathrate hydrates in systems with seawater : towards advancement of novel energy technologies

  Omura, Ryo

  科学研究費補助金研究成果報告書 2012

• Thermal engineering studies of double-hydrate formation : attempts toward establishing new energy-utilization technologies

  Omura, Ryo

  科学研究費補助金研究成果報告書 2010

• Investigation into variations in hydrate crystal morphology

  Omura, Ryo

  科学研究費補助金研究成果報告書 2009

Presentations 【 Display / hide 】

Presentations 【 Display / hide 】

• 二酸化炭素分離に適したクラスレートハイドレートの探索と物性測定

  Ohmura Ryo

  化学工学会第46回秋季大会, 

  2014.09

  , 

  Oral presentation (invited, special), 公益社団法人 化学工学会

• Crystallographic structure and thermodynamic stability of clathrate hydrates formed with halogen-containing guests

  Ryo Ohmura

  2012 "Natural Gas Hydrate Systems" Gordon Research Conference (Ventura, CA) , 

  2012.03

  , 

  Oral presentation (invited, special)

• Crystal growth of clathrate hydrates in hydrophobic-guest fluid + liquid-water systems

  Ohmura Ryo

  ACS 241st National Meeting (Anaheim, CA, USA) , 

  2011.03

  , 

  Oral presentation (invited, special), American Chemical Society

• Understanding thermodynamics of clathrate hydrates toward energy/environment technology innovations

  Ohmura Ryo

  21st IUPAC International Conference on Chemical Thermodynamics Conference (ICCT-2010) (Tsukuba) , 

  2010.08

  , 

  Oral presentation (invited, special), IUPAC

• Combustion Characteristics of Methane Hydrate in a Laminar Boundary Layer

  Yuki Nakmura, Ryoji Katsuki, Takeshi Yokomori, Ryo Ohmura, Toshihisa Ueda, Masahiro Takahashi, Toru Iwasaki and Kazuo Uchida

  6th International Conference on Gas Hydrates (ICGH 2008) (Vancouver) , 

  2008.07

  , 

  Poster presentation

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Research Projects of Competitive Funds, etc. 【 Display / hide 】

Research Projects of Competitive Funds, etc. 【 Display / hide 】

• 海水と炭酸ガスの炭酸塩晶析反応に関する基礎研究

  2007.07

  -

  2008.03

  受託研究費, Commissioned ｒesearch, No Setting

• クラスレート水和物の結晶モルフォロジー多様性の解明

  2007.04

  -

  2008.03

  Grant-in-Aid for Scientific Research, Research grant, No Setting

• シクロペンタンハイドレートの生成特性の解明

  2006.10

  -

  2007.03

  東京電力株式会社, 共同研究費, Joint research, No Setting

• クラスレート水和物の結晶構造多様性を利用した省エネルギー天然ガス貯蔵・輸送技術に関する研究

  2005.10

  -

  2006.09

  NEDO, -, Research grant, No Setting

Intellectual Property Rights, etc. 【 Display / hide 】

Intellectual Property Rights, etc. 【 Display / hide 】

• 構造Hクラスレート水和物の生成方法

  Date announced： 特開2003-3181   

  Patent, Single

• 気体の分離剤及び気体を分離濃縮するための方法と装置

  Date announced： 特開2003-138281   

  Patent, Single

• 不凍タンパク質を用いた包接化合物の生成制御法

  Date announced： 特開2005-89353   

  Patent, Single

• トレハロースを用いた包接化合物の生成制御法

  Date announced： 特開2005-89331   

  Patent, Single

• 新規構造H水和物

  Date announced： 特願2004-355852   

  Patent, Joint

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Awards 【 Display / hide 】

Awards 【 Display / hide 】

• 日本機械学会奨励賞（研究）

  大村　亮, 2004.04, 日本機械学会, クラスレートハイドレートに関する熱工学的研究

• 日本機械学会奨励賞（研究）

  Ohmura Ryo, 2004.04, クラスレートハイドレートに関する熱工学的研究

  Type of Award： Award from Japanese society, conference, symposium, etc.

Courses Taught 【 Display / hide 】

Courses Taught 【 Display / hide 】

• THERMAL ENGINEERING

  2025

• PHYSICAL CHEMISTRY OF MOLECULAR CRYSTALS

  2025

• INTRODUCTION TO THERMODYNAMICS

  2025

• INTRODUCTION TO INTERDISCIPLINARY SCIENCE AND TECHNOLOGY

  2025

• INDEPENDENT STUDY ON SCIENCE FOR OPEN AND ENVIRONMENTAL SYSTEMS

  2025

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Social Activities 【 Display / hide 】

Social Activities 【 Display / hide 】

• ガスハイドレート産業創出イノベーション

  2006.09

  -

  Present

  　View Summary

  産業技術総合研究所が主催する研究会の会員．産総研，民間企業，大学から会員を集め，ハイドレート利用技術の事業化へ向けた取り組みを進める．

• 天然ガスハイドレート製造利用システム実証特別委員会

  2006.08

  -

  2008.03

  　View Summary

  上記委員会はNEDOから三井造船（株）と中国電力（株）への委託事業におけるプロジェクトリーダーの諮問機関という位置づけ

• NEDO平成17年度「天然ガスハイドレート技術の国内市場への適用可能性調査」検討委員会

  2005.04

  -

  2005.07

  　View Summary

  NEDOから（財）エネルギー総合工学研究所への委託研究の検討委員会委員

Memberships in Academic Societies 【 Display / hide 】

Memberships in Academic Societies 【 Display / hide 】

• 日本機械学会, 

  2011.04

  -

  Present

• 日本機械学会　メカライフ編集委員会, 

  2007.04

  -

  2008.03

• 日本機械学会熱工学部門 広報委員, 

  2005.04

  -

  2006.03

Committee Experiences 【 Display / hide 】

Committee Experiences 【 Display / hide 】

• 2011.04

  -

  Present

  Committee Member, 日本機械学会

• 2007.04

  -

  2008.03

  Committee Member, 日本機械学会　メカライフ編集委員会

• 2006.09

  -

  Present

  Member, ガスハイドレート産業創出イノベーション

  　View Remarks

  産業技術総合研究所が主催する研究会の会員．産総研，民間企業，大学から会員を集め，ハイドレート利用技術の事業化へ向けた取り組みを進める．

• 2006.08

  -

  2008.03

  Committee Member, 天然ガスハイドレート製造利用システム実証特別委員会

  　View Remarks

  上記委員会はNEDOから三井造船（株）と中国電力（株）への委託事業におけるプロジェクトリーダーの諮問機関という位置づけ

• 2005.04

  -

  2006.03

  Committee Member, 日本機械学会熱工学部門 広報委員

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