Identification and analysis of mass transfer coefficients and effective diffusion coefficients for models of solvent extraction of Montan wax

Montan wax extraction which is considered to be an application of solid–liquid extraction (leaching) was systematically studied. Different mass transfer models for Montan wax extraction of brown coal–toluene system are established to simulate and analyse the extraction process with fixed-bed extractors and stirred extractors. Empirical correlations are applied to determine the mass transfer coefficients and the axial diffusion coefficient . A method (denoted as Opt-empirical method) to estimate the effective diffusion coefficient is proposed for the Montan wax extraction, which is validated by using sets of experimental data in percolation columns and stirred extractors.