Continuous Separation of Sugarcane Molasses with a Simulated Moving-Bed Adsorber. Adsorption Equilibria, Kinetics, and Application

Abstract

Fundamental chromatographic properties are reported that are related to the industrial separation of sugarcane molasses in a simulated moving-bed adsorber. The distribution coefficients of KCl, sucrose, glucose, and fructose on XUS-40166.00 (K⁺) cation exchanger were determined by pulse testing to be 0.00, 0.22, 0.45, and 0.50 at infinite dilution at 70°C. The adsorption isotherm of KCl is quadratic; those of the sugars only slightly nonlinear and dependent on KCl concentration. HETP was found to be independent of fluid velocity for KCl in the range of the interstitial velocity of 5 to 35 cm/min, and increasing with v for sucrose. At high fluid velocities the broadening of the sucrose band in a packed bed comes primarily from intraparticle mass transfer, with axial dispersion and film diffusion playing minor roles. The process for separation of sugarcane molasses was demonstrated on a 47-L, eight-column simulated moving-bed adsorber. A theoretical, staged model of the simulated moving-bed adsorber with one inert totally excluded and three linearly adsorbing components was found to give an excellent representation of the transient and steady-state behavior of the continuous separation of sugarcane molasses.