Distillation in a Counterflow Concentric-Ring Rotating Bed

Abstract

Developed from rotating zigzag bed (RZB), the counterflow concentric-ring rotating bed uses a rotor composed of stationary–rotating discs, a set of concentric circular rotating rings with perforations, and a liquid distribution at the eye of the rotor, preserving the outstanding characteristics of RZBs consisting of intermediate feeding and multirotors coaxially installed in series in a casing. A mass-transfer model was proposed from which the local gas- and liquid-side mass-transfer coefficients, gas–liquid effective interfacial area, and height equivalent to theoretical plate (HETP) can be calculated. Total reflux distillation experiments were conducted in a counterflow concentric-ring rotating bed at atmospheric pressure using an ethanol–water system, and the mass-transfer end effects were also investigated. The experimental values of overall volumetric gas-side mass-transfer coefficient and HETP agree with the calculated values very well. Obvious end effects exist in the distillation process, and a co...