Towards realistic characterisation of chemical reactors: An in-depth analysis of catalytic particle beds produced by sieving

Combining Theoretical and Experimental Methods to Probe Confinement within Microporous Solid Acid Catalysts for Alcohol Dehydration

“…The ethanol conversion for SAPO-34 remains constant, despite changes in operating parameters, suggesting that this is not a kinetic effect. Recent works suggest that this could be due to our conditions, where SAPO-34 only is approaching equilibrium conversion for ethanol dehydration, and agree with our findings that lower temperature favors diethyl ether formation, before this subsequently forms ethene, and this may also be due to nonoptimized reactor design or catalyst packing within the fixed bed . In our previous works, the activation energies of three possible reaction steps were found to be between 66 and 143 kJ/mol, under similar conditions, as those employed here.…”

“…Recent works suggest that this could be due to our conditions, where SAPO-34 only is approaching equilibrium conversion for ethanol dehydration, 113 and agree with our findings that lower temperature favors diethyl ether formation, before this subsequently forms ethene, and this may also be due to nonoptimized reactor design or catalyst packing within the fixed bed. 114 In our previous works, the activation energies of three possible reaction steps were found to be between 66 and 143 kJ/mol, under similar conditions, as those employed here. These values are orders of magnitude higher than what would be expected for pore diffusion processes, suggesting that the system is not pore diffusion limited.…”

Quantifying the Impact of Intraparticle Convection within Fixed Beds Formed by Catalytic Particles with Low Macro-Porosities

“…66,67 For this system, we have previously demonstrated the potential of CFD models, developed for ANSYS Fluent, as investigate tools. 66,67 Moreover, by mapping the internal structure of the bed, we identified its highly heterogeneous nature, consisting of particles with a wide range of sizes, shapes, and orientations, 19 leading to flow profiles with large velocity and pressure gradients. 22 However, the internal structure of the SAPO-34 particles was not discussed.…”

“…In recent years, computational fluid dynamics (CFD) models have been instrumental in the advancement of fixed bed chemical reactors, which are utilized both as investigative and as optimization tools. ,− In particle-resolved CFD (PR-CFD) models, realistic particle arrangements are generated primarily through the discrete element method (DEM), ,, and the individual particles are resolved and meshed. Particle sizes and shapes within the packed bed can either be mono- − or poly-dispersed − in nature, with modern DEM-based beds implementing multiple particle shapes, such as spherical, cylindrical, or Raschig rings. ,,,,− PR-CFD models yield key information regarding the interconnected nature of the physicochemical phenomena during operation of the fixed bed system. ,, Specifically, their ability to consider the impact of the geometrical bed structure to predict the interparticle heat and mass transfer yields highly valuable insights for reactor engineering. − Fixed bed reactors include different levels of “porosity” (Figure ). The particles (gray spheres in Figure a) are immobile, having interconnected gaps between them, referred to as “interparticle network”, where reagents can flow through.…”

“…We focus here purely on catalytic particles with low macro-porosities, i.e., below 0.5, as they exist in-between the spectrum of a completely solid particle and an open-cell foam-type particle. In our previous work, we have investigated the performance of SAPO-34 for EtOH dehydration. ,, The strong acid sites and small micropores of SAPO-34 made it highly selective for ethylene formation. , For this system, we have previously demonstrated the potential of CFD models, developed for ANSYS Fluent, as investigate tools. , Moreover, by mapping the internal structure of the bed, we identified its highly heterogeneous nature, consisting of particles with a wide range of sizes, shapes, and orientations, leading to flow profiles with large velocity and pressure gradients . However, the internal structure of the SAPO-34 particles was not discussed.…”