The impact of different sealing types and their wearing on the separation performance in distillation processes in rotating packed beds (RPB) has been investigated, which potentially causes bypass flows inside the unit. In the literature, a maximum separation performance is observed, which can have several possible explanations. Next to the theory that with increasing rotational speed a lower residence time counteracts the mass transfer intensification, one theory is that there are undetected bypasses from the casing of the unit to the eye of the rotor. Besides the effect of the maximum, the latter would indicate the fact that bypasses generally induce lower separation performance in RPBs. However, with a suitable sealing concept, higher separation performances could be achieved in the units. Therefore, the influence of bypass flows on the separation performance was investigated by installing different sealings in the RPB, which has not yet been discussed. For this purpose, two sealing types, a labyrinth and a floating ring sealing, were tested in two different RPBs of similar design. The results showed that the labyrinth sealing was less effective than the floating ring sealing in reducing the bypass mass flow. For the floating ring sealing, the separation performance dropped with increasing operation time due to abrasion and wearing. The results also showed that, in general, with increasing rotational speed, the tightness of the sealings is reduced, leading to the formation of bypass streams that reduce the separation performance of the plant. The study highlights the need for greater awareness of bypasses in RPBs especially concerning the separation performance and emphasizes the demand to develop more efficient and effective sealing systems that are ideally nonabrasive, require no additional fluids, and have higher tightness. These findings could call for re-evaluation of previous results, packing evaluations, and derived models.

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