Radial Temperature Profile Measurements to Understand Mass Transfer in Rotating Packed Bed Distillation

Abstract

There is a considerable demand to understand the mass transfer fundamentals in rotating packed beds (RPB), especially for vapor-side controlled processes. An online measurement method allowing the determination of radial temperature profiles was developed to calculate the separation efficiency in the packing and casing via known VLE data. Furthermore, a radial separation efficiency profile was established to understand the nonuniformities in the separation performance of different packing parts that will eventually help optimize the packing design. Binary distillation experiments were carried out with an ethanol–water system in a packed and empty rotor. Investigations show that the radial separation efficiency achieved along the radius is a function of rotational speed and radial packing length, showing a maximum in the middle of the packed rotor under the operating and design conditions investigated. Furthermore, initial radial temperature profile measurements with an advanced Zickzack packing, developed by additive manufacturing, showed that the loss of separation efficiency due to radial liquid maldistribution in conventional RPB packings could be reduced with the proper packing design, enabling uniform liquid distribution.