Electrostatic separation of pea proteins assisted by COMSOL simulation

Abstract

To address the dilemma of inefficient plant protein electrostatic separation, some optimization strategies were proposed by combining experimental analysis with COMSOL Multiphysics simulation. Micronized pea powder was obtained by airflow impact mill. The design of a near-cylindrical buffer zone (diameter 6.2 cm, height 10 cm) above the separation chamber can convert the turbulent flow from the tribo-charging system into laminar, slow down the airflow velocity and weaken propulsion on the particles. Moderate particle charge (464.8 ± 24.9 nC/g) and high electric field strength (2.0 kV/cm) can ensure the required electric field force for separation while reducing inter-particle aggregation. The formation of a steady magnetic field by two neodymium magnets, placed perpendicular to the electric field, was a potentially valuable auxiliary force in the separation of charged particles, but strictly limited by the magnetic field strength. With those improvements, pea protein concentrate purity was increased from 27.8 ± 0.5% (db) to 62.6 ± 0.6% (db) after one-step electrostatic separation. Combined with the visualization of simulation, this study provided a new insight into improving the electrostatic separation efficiency of micronized powder. • Pre-slowing airflow velocity through buffer zone improves separation efficiency. • Particle aggregation due to high charge negatively impacts separation. • Moderate particle charging and high separation voltage is the optimal strategy. • High intensity magnetic field can separate different charged particles exclusively. • Numerical simulation of separation field, airflow and charged particle trajectory.