Heterogeneous modeling approach for gas-limited reactions in an inclined rotating fixed bed reactor with stratified flow


Heterogeneous modeling approach for gas-limited reactions in an inclined rotating fixed bed reactor with stratified flow

Timaeus, R.; Schubert, M.; Hampel, U.

Mass transfer limitations in multiphase reactions are a widespread phenomenon in reaction engineering. Particularly in trickle bed reactors, space-time yield is limited due to the low accessibility of the gaseous educts to the solid catalyst. The inclined rotating fixed bed reactor is a new intensification strategy for trickle bed reactors to circumvent this bottleneck. The superposition of reactor inclination and rotation results in a stratified flow, which causes wetting intermittency of the catalytic fixed bed with alternatingly unhindered access of gas and liquid educts to the catalyst. The conversion for the α-methylstyrene hydrogenation has been doubled with the new reactor concept compared to the trickle bed operation, which highlights the potential of the process intensification strategy [1].
Within a DFG-funded project, a feasible model approach for the prediction of the space-time yield of the process intensification strategy is developed. In order to identify the most beneficial process windows and proper design parameters, a reactor model framework consisting of a two-phase Eulerian-Eulerian model and a heterogeneous continuum model to describe the hydrodynamics and to capture mass transfer and reaction phenomena, respectively, is proposed. In this contribution, the heterogeneous one-dimensional continuum model accounting for intraparticle gradients with time-dependent Neumann boundary conditions at particle scale is implemented. While the catalyst wetting intermittency leads to dynamic species concentrations at the particle scale, the species concentrations of the liquid bulk phase are stationary. Coupling of the different scales is realized by a two-way approach, using the species concentrations on each scale. The implemented model is applied for simulation studies considering the hydrogenation of α-methylstyrene to cumene in order to investigate the influence of period length via reactor rotation velocity and the wetting/draining cycle via flow stratification defined as split on the space-time yield.

Keywords: Inclined rotating fixed bed reactor; process intensification; modeling

  • Poster
    Jahrestreffen Reaktionstechnik 2018, 07.05.2018, Würzburg, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-28413
Publ.-Id: 28413