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The growing demand for flexible and compact separation technologies has promoted the application of high‐gravity technology, like rotating packed beds (RPBs). Mass transfer characterization and packing design play an important role in the development of this technology. This article provides a systematic approach towards the evaluation of packing and the development of advanced packing design for distillation in RPBs. For the latter, an additive manufacturing approach is used to develop a new Zickzack packing for RPBs. The new packing provides better mass transfer at reduced pressure drop compared to available conventional packings, while being competitive in terms of mass transfer with the industrially applied rotating zigzag bed at significantly reduced pressure drop.

The capacity of today's gas‐liquid contacting equipment such as tray or packed columns is limited by the gravitational‐driven liquid flow. Intensified equipment applying centrifugal force offers great potential for enhancing the mass transfer and for reducing equipment size. Yet, detailed knowledge about the liquid flow inside rotating packings is scarce due to limited accessibility with conventional measurement systems. In this study, a gamma‐ray computed tomography is employed to quantify the liquid hold‐up and its distribution in the moving packing.

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Carbon dioxide is considered the most important contributor to the global warming effect. To reduce greenhouse gas emissions, CO 2 should be separated from the exhaust gas stream in a selective way. The most often applied technology to capture CO 2 from exhaust gases is the reactive absorption in aqueous amine solutions, which is currently widely used in different industrial applications. The efficiency of this technology could be improved by applying high-gravity technologies that intensify mass transfer and can enable substantial equipment size reduction compared to the traditionally used packed columns. Rotating packed bed (RPB) technology meets these requirements very well. Applying innovative materials such as the highly efficient enzyme carbonic anhydrase can further improve the efficiency of the CO 2 absorption process. This combination of intensified technology together with new solvents is expected to improve the total efficiency of CO 2 absorption. In this study, we present our experimental results of CO 2 absorption using 30 wt% N-methyldiethanolamine (MDEA) solution in water in an RPB unit with and without carbonic anhydrase for different gas and liquid flow rates. The results indicate significantly improved performance of CO 2 absorption, up to 18 times compared to the solvent without enzyme. Keywords Rotating packed bed • RPB • CO 2 absorption • Carbonic anhydrase • MDEA Symbols a Specific surface area of the packing m 2 m −3 A Cross-section area m 2 c %MDEA MDEA concentration in water solution % F factor F factor Pa 0.5 M MDEA Molar mass of MDEA kg kmol −1 n CO 2 ,abs Molar flow rate of total absorbed CO 2 mol h −1 n CO 2 ,abs,packing Molar flow rate of absorbed CO 2 inside the packing mol h −1ṅ CO 2 ,abs,case Molar flow rate of absorbed CO 2 in the casing mol h −1 n G in CO 2 Molar flow rate of CO 2 in gas inlet mol h −1 n G inside CO 2 Molar flow rate of CO 2 in the casing mol h −1 n G out CO 2 Molar flow rate of CO 2 in gas outlet mol h −1 p Pressure Pa R Gas constant J mol −1 K −1 T Temperature K u L Specific liquid load m 3 m −2 h −1 v in CO 2 Volume fraction of CO 2 in gas inlet m 3 m −3 v inside CO 2 Volume fraction of CO 2 in gas m 3 m −3 v out CO 2 Volume fraction of CO 2 in gas outlet m 3 m −3 V G Volumetric gas flow m 3 h −1 V L Volumetric liquid flow m 3 h −1 Y CO 2 CO 2 loading mol mol −1 Greek letters Porosity of the packing m 3 m −3 G Density of gas kg m −3 MDEA Density of MDEA kg m −3

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