Power production from coal-mine brine utilizing reversed electrodialysis

Abstract

The present work was aimed at electric energy obtaining by mixing coal-mine brine with low-salinity water utilizing reversed electrodialysis (RED). The electrodialytic unit equipped with alternatively arranged cation and anion exchange membranes, was mounted in-between two Pt-coated electrodes. The number of the anion and cation-exchange membranes was set to achieve 4 brine and 4 low-salinity water compartments. The relatively thin, of 0.19 mm thickness, ED stack spacer enabled low membrane to membrane distance and resulted in relatively low ohmic voltage loss. The electrodialytic system was fed with brine, containing 111 g NaCl/L, simulating coal-mine brine and low-salinity water of 0.56 g/L NaCl content, as a fresh water. In order to estimate the possible electric charge and electric power produced in the proposed system, the current–voltage curves were analyzed at different linear flow velocities. Also the cost estimation based on the electric resistances was done. Thus the feasibility of electric energy obtaining in the considered way was discussed.