Optimizing ethanol recovery in a spinning cone column

Abstract

Spinning cone column (SCC) is a separation technology used in the food industry to recover natural aro- mas. It outperforms plate and packed columns given its enhanced mass transfer and capability to process slurries. Limited SCC design and operating guidelines are available, since theoretical studies characterized the SCC hydrodynamics with single components, while experimental studies with complex mixtures do not consider process modeling and optimization. Distillation of a water–ethanol mixture of 14.8% (v/v) in a lab scale SCC was optimized, varying the stripping rate, feed rate and temperature. A first principles model was developed to explain the results in terms of internal variables. Three operating regions were identified. At low stripping rates, the operation was unstable and low performing. At high stripping rates, ethanol recovery and concentration decreased due to a sharp increase in the heat loss that overweighed the mass transfer enhancement. To maximize recoveries, SCC should operate at intermediate-high strip- ping rates, high feed and intermediate temperatures. A high-performance region was found with ethanol recoveries higher than 94% and ethanol concentrations in the distillate over 70%. Our proposed guidelines improve the competitiveness of wine and beer dealcoholization using SCC technology, increasing the yield and marketability of both dealcoholized product and surplus distillate.