Performance of Reverse Electrodialysis System for Salinity Gradient Energy Generation by Using a Commercial Ion Exchange Membrane Pair with Homogeneous Bulk Structure

Esra Altıok,Marek Bryjak,Nalan Kabay,Enver Güler,Tuğçe Zeynep Kaya

doi:10.3390/w13060814

Abstract

Salinity gradient energy is a prominent alternative and maintainable energy source, which has considerable potential. Reverse electrodialysis (RED) is one of the most widely studied methods to extract this energy. Despite the considerable progress in research, optimization of RED process is still ongoing. In this study, effects of the number of membrane pairs, ratio of salinity gradient and feed velocity on power generation via the reverse electrodialysis (RED) system were investigated by using Fujifilm cation exchange membrane (CEM Type 2) and FujiFilm anion exchange membrane (AEM Type 2) ion exchange membranes. In the literature, there is no previous study based on a RED system equipped with Fujifilm AEM Type II and CEM Type II membranes that have homogeneous bulk structure. Using 400 µm of intermembrane distance, maximum obtainable power density by 5 pairs of Fujifilm membranes at 1:45 salinity ratio and with a linear flow rate of 0.833 cm/s was 0.426 W/m2.

Highlights

There is a growing need to reduce CO2 emissions to the environment due to theKyoto Protocol and the Intergovernmental Panel on Climate Change (IPCC) Report on carbon dioxide capture and storage [1]
Operational parameters were grouped properly to see the effect of the membrane pair, feed solution, salinity ratio and linear flow rate of the feed solution on power density and open circuit voltage
Power and maximum power density values were determined after the subtraction of V ·I values obtained in blank tests

Summary

Introduction

There is a growing need to reduce CO2 emissions to the environment due to theKyoto Protocol and the Intergovernmental Panel on Climate Change (IPCC) Report on carbon dioxide capture and storage [1]. The use of alternative energy sources with reduced or no CO2 emissions can be considered in order to achieve this purpose [1]. Salinity gradient energy (SGE) known as “blue energy” is an alternative and maintainable source of energy, which has potential for growth since it was first identified in the 1950s [3]. Salinity gradient power is a new and non-polluting energy source, which can be generated from the difference in the chemical potential between two solutions with different salt concentrations [4], without emission of toxic gases [1,5]. Free energy is generated by combining fresh water with salt water, thereby converting the chemical potential of low salinity water and high salinity water into electrical energy [1,5]

Methods

Results

Conclusion