Enhancement of distillation efficiency by application of an electric field

The effects of an applied electric field on distillation were investigated using a laboratory-scale two-stage column. The electric field was applied i n the liquid region between a distillation plate and a rod-shaped electrode immersed in the liquid and placed parallel to the plate. It was found that the distillation column performance, i.e., the plate efficiency and distil late flow rate, can be increased by application of a direct-current (DC) el ectric field to the liquid phase of the plate. The cause for such an increa se in the distillation efficiency appears to be the enhancement in mass- an d heat-transfer rates under the applied electric field. For a binary system of water and 2-propanol, a 2.2% increase in the plate efficiency of the se cond stage and a 4-fold increase in the distillate flow rate were obtained by application of a voltage of 14 kV. A 20% increase in the heat energy inp ut was observed under this voltage. These enhancements were not observed in the distillation of a nonconductive binary system containing 2-butanone an d toluene with applied voltages of up to 30 kV.