On the relative contribution of solid-phase heat transfer in 3D printed baffled logpile catalyst structures

Abstract

Recently introduced 3D printed baffled logpile catalyst structures provide increased fluid-phase convective heat transfer thanks to a cross-flow regime, leading to a favorable trade-off between heat transfer and pressure drop in fixed bed reactors. The role of the solid-phase heat transfer was not yet addressed, which is the purpose of the current work. Specifically, 3D computational fluid dynamics simulations were used to map the heat transfer — pressure drop trade-off for nine different structures as a function of the superficial velocity and the solid-phase thermal conductivity. It was found that for structures without baffles, the solid-phase heat transfer dominates even at low solid-phase thermal conductivity (0.25Wm−1K−1). As the baffle gap spacing decreases, the fluid-phase contribution becomes increasingly more relevant for the baffled structures, underlining the added value of the baffles. The performance parameters were correlated to facilitate design considerations for reactors with 3D printed catalyst internals (in the range 3<Rep<18). An exemplary reaction case was also presented, through which it is shown that the conversion of the steam methane reforming process can be increased through the use of the baffled structures, further demonstrating the process intensification potential.