Development of TPMS Lattice Substrates for Catalytic Cracking Applications via Fused Filament Fabrication

The advancement of catalytic substrates through Additive Manufacturing (AM) offers notable benefits over conventional techniques, particularly for producing intricate three-dimensional forms that enable precise control over pore dimensions and surface characteristics. These attributes play a vital role in improving catalytic efficiency, which is evaluated by measuring pressure drop and mass transfer. This research focuses on the design and manufacture of a monolithic ceramic filter for catalytic cracking. The monoliths under study have a Triply Periodic Minimal Surface (TPMS) lattice. A macroporosity of about 65% is the criterion used to model the structures, and the TPMS unit cell length is the design parameter to achieve that porosity. Adapting a conventional Fused Filament Fabrication (FFF) desktop to use alumina filament, we produced samples based on three TPMS types: Schwar-Primitive (SP), Schoen Gyroid (SG), and Schwarz-Diamond (SD), which, after a plastic debinding process and subsequent sintering, resulted in meso-scale porous structures. The samples showed relative dimensional errors below 5% and a real total porosity of around 70%, with a maximum difference of 4% among the TPMS types. Because the printed SP lattices have the lowest unit cell length and real porosity, their pressure drop measurements were higher than those of the SG and SD. The opposite occurred with the estimated permeability. Although yielding similar pressure drop results, printed SG lattices had greater permeability than SD; therefore, in terms of monolith fluid dynamics, the SG lattice is the preferred geometry.