成果報告書詳細
管理番号20130000000797
タイトル *平成24年度中間年報 最先端PG(Mega-ton Water System)濃度差エネルギー回収(PRO)流体解析と発電システム No.2(H22-H25)
公開日2014/1/10
報告書年度2012 - 2012
委託先名長崎大学
プロジェクト番号P09025
部署名環境部
和文要約現行モジュール内の流動特性を基本として、様々なパラメータが浸透性能へ及ぼす影響をシミュレーションにより解析した。その結果、形状パラメータおよび、中空糸特性の各因子の影響を明らかにすることができた。また、可視化実験から、シミュレーションと同様に偏流が存在し、モジュールの性能が十分には発揮されていないことを示した。固体表面の極性基が拡散および浸透に及ぼす影響について分子動力学法を用いて検討した。その結果,膜表面の水酸基は液体の拡散を抑制すること,膜内部の水酸基は浸透量を増大させることが分かった。この結果は,浸透量が多く,濃度分極が発生しにくい膜は,膜表面は疎水性,膜内部は親水性であることが望ましいことを示している。
英文要約Pressure Retarded Osmosis (PRO) system with hollow fiber elements is examined by using the RO module for the power generation. The present hollow fiber element doesn’t work effectively if the module and the element for SWRO are used without modification. The flow diagram of pure water and brine inside the module and the element at PRO operation is different from those at RO operation. In this paper, it is analyzed the concentrated brine flow in the module of PRO operation with the numerical simulation. The influences of the water permeability coefficient and the flow rate of the concentrated brine are investigated. The flow of the concentration brine in the center pipe reaches to the end and the velocity is very large. The flow in the hollow fiber element is a little large only near the outlet of the module. But the major part of the element is fairly small compared to in the pipe. The salt concentration in the hollow fiber element is very low at the inlet side and gradually increased toward to the outlet. The salt concentration at the exit of the module is about 6%. It indicates that the pure water is not sufficiently penetrated because of the distorted flow condition. The osmotic pressure that is evaluated from the salt concentration is gradually decreases toward to the radial direction. Near the outlet of the module, the osmotic pressure is kept large up to the outlet, but the osmotic pressure at the other part of element is low. The amount of the osmosis of fresh water is fairly distorted for the variation of the osmotic pressure. The location where the velocity of the concentrated brine is small, the fluid is lost to the brine flow and the low concentrated fluid is left. This result indicates that the increment of the water permeability coefficient is not always increased the amount of osmosis and there exist the optimal condition for the each module geometry. It is seemed to be useful for future PRO or FO module design.Molecular dynamics simulations are conducted to examine the effects of the polar group in membrane molecule on the behaviors of liquid molecules in the vicinity of solid surface. The results show that the polar group on a membrane surface decreases the diffusion of liquid molecules and that in a membrane inside increase the amount of osmosis water.This indicates that the membrane that has hydrophobic character on surface and hydrophilic character on the inside is desirable for osmotic action.
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