Simulation-based design of a bipolar membranes electrodialysis unit for chemicals production from brines

Abstract

Nowadays environmental concerns are modifying the production and consumption patterns used so far. An important objective to improve our society is the use of sustainable processes that can reduce industrial waste streams. Bipolar membranes electrodialysis (EDBM) is an emerging environmentally friendly process that could be easily integrated into a circular economy approach to valorize waste brines. It is an electro-membrane process that allows the production of chemicals using only water, electrical energy and a salty solution. When electric current is applied to the electrodes of the EDBM stack, water dissociation takes place in the bipolar membranes. Therefore, the ions from water are combined with those coming from the salt generating acid and base. The increasing interest in the EDBM process requires appropriate design procedures. This study proposed a simulation-based design of a EDBM unit for the production of hydrochloric acid and sodium hydroxide from sodium chloride solution. The design was performed in terms of configuration and operational conditions. A model, realized by Culcasi et al. [1], was used to describe the EDBM process’s behaviour. This model was validated with experimental data so that a high quality design could be achieved. This procedure was used to design a EDBM unit that will be part of the demo-plant of the Horizon 2020 Water-Mining project.