2016 Fiscal Year Annual Research Report
Freezing-based desalination: A molecular approach to understanding and optimisation.
| Project/Area Number |
26820059
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| Research Institution | Kyushu University |
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Principal Investigator |
Cannon James 九州大学, 工学研究院, 准教授 (80648866)
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| Project Period (FY) |
2014-04-01 – 2017-03-31
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| Keywords | Freezing / Desalination / Liquids / Thermal conductivity / Viscosity / Thermophysical / Molecular simulation |
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| Outline of Annual Research Achievements |
For the successful development of a freezing-based desalination system, an understanding of the mechanisms by which the thermo-physical properties of water are modified in the presence of impurities is of paramount importance. In particular, the ability of water to transport heat away from a surface has a direct impact on the rate of freezing at supercooled temperatures. This must be considered in conjunction with viscosity, which has a direct influence on the energy required to pump water around the desalination system. For these reasons, work has focussed on the properties of water with variation in impurity molecular structure, attempting to derive a quantitative model of how thermo-physical properties vary.
Building upon the success in previous years of developing calculation methods and software capabilities, modern statistical analysis methods were utilised to derive a relation between thermal conductivity and viscosity for a model liquid system (water + impurity), based only on knowledge of the molecular atomic properties of the impurity, such as atom interaction strengths, bond-lengths and so on.
Based upon this, a quantitative relation between the structure of a model molecule (in this case, glycol-like molecule) and its thermal conductivity and viscosity was achieved. Furthermore, it was made clear how to quantitatively predict and decouple these two key thermo-physical properties based on molecular structure, marking a major milestone in the progress of the project.
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