Sucrose Recovery from Diluted Cane Molasses by Using Mass-transfer to The Third Liquid Layer at Contacting with Ethanol

Abstract

A simple rate-based method for recovering sucrose from sugarcane molasses is proposed, focusing on the feasibility of continuous processing. When ethanol is gently poured onto diluted molasses, sucrose is transferred to ethanol along with water, resulting in the formation of a distinct third layer composing sucrose positioned between the ethanol and diluted molasses. Although the third liquid layer is metastable and dissipates when vigorously stirred, its sucrose concentration reaches a level suitable for sucrose crystal formation. Consequently, by continuously withdrawing the third layer while supplying ethanol to the diluted molasses, a semi-continuous operation for sucrose recovery from diluted molasses is achieved. To predict the concentration changes of sucrose over time within the third liquid layer, simple mass-transfer models based on diffusion and axial dispersion are employed. While the prediction yields limited success, it underscores the significance of mass-transfer from the liquid jet in the third layer and the role of mild mixing within the layer in facilitating its growth and interior mass-transfer. This study presents the first description of the effective utilization of the third liquid layer in solvent extraction and a method to control its formation and mass-transfer for sugar recovery from molasses.