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Gas-liquid mass transfer in inclined rotating fixed bed reactors

Härting, H.-U.; Wiezorek, M.; Schubert, M.

Periodic operation of trickle bed reactors (TBR) as a promising process intensification approach has been examined in many studies since more than 2 decades. It has been demonstrated to reduce known limitations and disadvantages of the conventional operation mode of such reactors, i. e. avoiding the formation of hot spots, enhancing liquid maldistribution and boosting poor mass transfer rates. Though widely examined in the academic field, an industrial implementation of periodically operated TBRs is not expected, mostly because of the higher requirements on the upstream peripheral devices in an industrial environment. Additionally, modelling and prediction of the transient behaviour of such reactors remain challenging tasks due to the complex hydrodynamics and related mass and heat transfer resulting from the dynamic mode of operation. As a consequence, alternative reactor concepts with enhanced performance which do not require flow modulation but potentially provide benefits over established configurations need to be studied.

To avoid the problem of shorter residence times arising from the pulse flow regime while maintaining a periodic wetting and draining of the packed bed, a superimposed rotation of the inclined TBR is proposed. This new concept allows process intensification via a spatial periodic mode of operation while feeding with invariant gas and liquid flow rates. Inclination angle and reactor rotational speed provide additional degrees of freedom to adjust liquid residence time and period length (periodicity), respectively.

The objective of this study is the systematic investigation of the influence of inclination and rotation on the gas-liquid mass transfer for selected gas and liquid flow rates. Therefore, oxygen desorption in a reactor (1.6 m length, 0.1 m diameter) with particle packing (4 mm diameter) will be studied and mass transfer coefficients determined. The mass transfer results will also be discussed with respect to flow patterns obtained from tomographic imaging. Furthermore, the results will be compared with experimental data of the conventional TBR configuration as well as with established correlations.

Keywords: Fixed bed reactor; Inclination; Rotation; Mass transfer; Phase distribution; Gamma-ray tomography

  • Lecture (Conference)
    20th International Congress of Chemical and Process Engineering CHISA 2012, 25.-29.08.2012, Praha, Česká republika

Permalink: https://www.hzdr.de/publications/Publ-17338
Publ.-Id: 17338