Process intensification in mass-transfer limited catalytic reactors through anisotropic periodic open cellular structures

We propose an advanced design of catalyst supports based on Periodic Open Cellular Structures (POCS) with a modified diamond unit cell. The diamond unit cell is modified by changing the angle between the struts and the fluid direction, thus changing the fluid-solid interaction and consequently the gas-solid mass and momentum transfer properties. Computational Fluid Dynamics is employed to fundamentally investigate the transport phenomena, and to carry out a parametric investigation of the effects of the morphological properties (i.e., struts angle, porosity and unit cell size). A drastic reduction of the friction factor (i.e., up to 50%) at moderate reduction of the mass transfer coefficient (i.e., up to 30%) is observed in the modified configuration upon progressively aligning the struts with the flow direction. This results in an overall improvement of the trade-off between the two properties leading to superior overall performances compared to state-of-the-art structured substrates. Unifying engineering correlations are then developed based on the numerical results for the evaluation of mass transfer coefficients and friction factors of the POCS, describing the behaviour of both the conventional and the modified cellular structure.