Mass-transfer characteristics in a rotating zigzag bed as a Higee device

Abstract

Abstract A rotating zigzag bed, as a Higee device, has successfully achieved the industrialization of Higee in the commercial continuous distillation process. To increase applicability of rotating zigzag bed in the gas-liquid mass-transfer processes, the mass-transfer characteristics of the rotor of rotating zigzag bed were examined. The effective interfacial area ( a e ) and local liquid-side mass-transfer coefficient ( k L ) were measured using a chemical absorption of CO 2 in NaOH solution. Based on two-film theory, the local gas-side mass-transfer coefficient ( k G ) was obtained from the overall volumetric gas-side mass-transfer coefficient ( K G a e ) which was measured using a stripping of ethanol from an ethanol-water mixture by air. The effects of rotational speed, liquid volumetric flow rate and gas volumetric flow rate on these mass-transfer parameters were investigated. Compared to the conventional rotating packed bed, the k L of the rotor of rotating zigzag bed was as about 2.5 times higher as that of conventional RPB rotor, and the a e and k G of the rotor of rotating zigzag bed matched with those of the rotor of conventional rotating packed bed. Therefore, rotating zigzag bed has good mass-transfer performance with a great potential for the industrial application.