Periodic Open Cellular Structures in Chemical Engineering: Application in Catalysis and Separation Processes.

Periodic open cellular structures (POCS) represent a promising new class of structured internals as next-generation catalyst supports in reactors or structured packing elements in separation columns. POCS feature a well-defined morphology and can be fabricated with high reproducibility even for complex geometries by means of additive manufacturing. This results in a uniform and easily controllable flow field, which allows for adjusting the heat and mass transport processes to realize optimal process conditions. We review the fundamentals of POCS, including design and manufacturing as well as transport phenomena for single- and multiphase systems. Moreover, we review recent POCS applications in reaction and separation processes and consider promising future application fields. The exceptional transport characteristics of POCS facilitate the design of highly efficient, flexible, resilient, and safe processes, which is key for achieving process intensification toward a sustainable future.

Selective oxidation of cyclohexanol to cyclohexanone in the ionic liquid 1-octyl-3-methylimidazolium chloride.

Ionic liquid (IL) 1-octyl-3-methylimidazolium chloride was found to effectively intensify cyclohexanol oxidation and resulted in 100% conversion of cyclohexanol with 100% selectivity to cyclohexanone using hydrogen peroxide as an oxidant and WO(3) as a catalyst. The effect of the IL as a solvent is discussed with the support of COSMO-RS theory.

Analysis of the flow field and pressure drop in fixed-bed reactors with the help of lattice Boltzmann simulations.

The pressure drop of technical devices is a crucial property for their design and operation. In this paper, we show how the results of lattice Boltzmann simulations can be used in science and engineering to improve the physical understanding of the pressure drop and the flow inhomogeneities in porous media, especially in sphere-packed fixed-bed reactors with low aspect ratios. Commonly used pressure drop correlations are based on simplified assumptions such as the capillary or tortuosity model, which do not reflect all hydrodynamic effects. Consequently, empirical correlations for certain classes of media have been introduced in the past to bridge the gap between the models and the experimental findings. As is shown in this paper by the detailed analysis of the velocity field in the void space of packed beds, the pressure drop is due to more complex hydrodynamics than considered in the above-mentioned models. With the help of lattice Boltzmann simulations, we were able to analyse the different contributions to the total dissipation, namely shear and deformation of the fluid, for different geometries over a wide range of Reynolds numbers. We further show that the actual length of the flow paths changes considerably with the radial and circumferential position.