Simulation of Electrodialysis with Bipolar Membranes: Estimation of Process Performance and Energy Consumption

A mathematical model of a typical three-compartment electrodialysis with bipolar membranes (EDBM) process has been developed to calculate the energy consumption and total cost of the process. In particular, gluconic acid was chosen as a model product, the energy consumption was calculated on the basis of the Nernst-Planck equation, Donnan equilibrium, and electroneutrality assumption. The concentration profiles and resistance distributions across the respective layers were also displayed. Results indicated that the resistances of the solutions, diffusion layers, and Donnan interfaces were highly dependent on the applied current. The resistances in the diffusion layers were the dominant resistances, while the resistances due to Donnan interfaces and resistances of the membranes could be neglected. The energy consumption of an EDBM process was increased with an increase in current. The energy consumption in the validation experiment was in good agreement with the prediction, suggesting the reliability of the model.