著者

比嘉 充

出版者

日本海水学会

雑誌

日本海水学会誌 (ISSN:03694550)

巻号頁・発行日

vol.73, no.1, pp.3-8, 2019 (Released:2020-10-01)

参考文献数

12

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One of the renewable energies is salinity gradient power which converts salinity gradient energy existing between salt water such as sea water and fresh water such as river water into electricity. Mixing 1 m3 of seawater with 1 m3 of fresh water theoretically generates 1.7 MJ of energy, which is equivalent to about 500 Wh. Salinity gradient power is expected as a base load power source derived from renewable energy with low environmental impact, high equipment utilization rate, and small footprint. There are two types of salinity gradient power using separation membranes: Pressure Retarded Osmosis (PRO) using semipermeable membranes, turbine and generators, and Reverse ElectroDialysis (RED) using ion exchange membranes. There were reports that in the case of using seawater, RED will be superior to PRO, and in the case of high concentration salt solution such as concentrated sea water etc. PRO will be better than RED. World's first RED power generation pilot plant was installed in Afsluitdiik, Netherlands. Recently, SWRO-PRO hybrid plant was built in Busan, Korea. In the future, the improvement in the performance of the forward osmosis membrane and ion exchange membrane will give practical applications of the two technologies.

著者

比嘉 充

出版者

日本海水学会

雑誌

日本海水学会誌 (ISSN:03694550)

巻号頁・発行日

vol.68, no.5, pp.293-297, 2014 (Released:2015-09-14)

参考文献数

6

著者

比嘉 充 遠藤 宣隆 垣花 百合子

出版者

山口大学

雑誌

基盤研究(B)

巻号頁・発行日

2013-04-01

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REDシステムを構成するモノリシック発電セル用の新規イオン交換膜はポリビニルアルコール(PVA)系ブロック共重合体から作製し、これらの膜は膜抵抗、イオン選択性において市販膜より優れた基礎性能を示した。また市販イオン交換膜を使用した大型RED発電装置は模擬海水として0.5MNaCl、模擬河川水として0.02MNaClを使用した場合、最大出力17.8W、出力密度0.45 W/m2を示した。この時の海水および淡水の供給圧と溶液流量から算出したポンプ電力は2.76 Wとなり、これより、15.1 Wの実効出力が得られた。この結果よりRED発電システムとしては将来のエネルギー源として期待できる。

著者

比嘉 充 藤井 将矢 岡川 直紀

出版者

日本海水学会

雑誌

日本海水学会誌 (ISSN:03694550)

巻号頁・発行日

vol.66, no.5, pp.242-247, 2012 (Released:2013-11-01)

参考文献数

17

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Salinity gradient power (SGP) is one of a renewable energy that is available when two solutions of different salinity mix. The global potential for SGP is calculated to be 2.6 TW when the flow of all rivers is taken into account. There are two membrane-based technologies that can change SGP into useful electricity ; reverse electrodialysis (RED) and pressure retarded osmosis (PRO). It has been shown that, in the case of river water with seawater, RED is a promising technology. The key components in a RED system are ion-exchange membranes (IEMs). Membrane requirements for RED are high perm-selectivity, low electrical resistance, safficent mechanical stability, high chemical stability, high anti-fouling properties and low cost. Here, the principle and technological trend of the system and IEMs for RED is presented.