Mass transfer simulation of main species in swine biogas slurry in bipolar membrane electrodialysis

Abstract

The aim of this model is to study the mass transfer of main species in swine biogas slurry in bipolar membrane electrodialysis. We developed a two-dimensional steady-state model composing three compartments. In this model, Nernst-Planck equation and Hagen-Poiseuille equation are combined for mass transfer and Faraday's law is for the electrolyte current density. The model considers local electroneutrality condition and does allow cations and anions pass through membranes. The set of equations with boundary conditions and initial values are calculated by the finite element numerical method with COMSOL Multiphysics. This model can be able to predict the distribution of electrolyte potential, the ion flux and the ion concentration distribution. The two parameters, cell voltage and inlet velocity, are indicated to have influences on the process of bipolar membrane electrodialysis treatment on swine biogas slurry.