Metal Foam as Surface-Extended Catalyst Support Structure for Process Intensification in the Dehydrogenation of Perhydro-Dibenzyltoluene on a Pt/Al2O3 Catalyst

Abstract

Dibenzyltoluene/perhydro-dibenzyltoluene (H0DBT/H18DBT) is considered a promising liquid organic hydrogen carrier (LOHC) pair for the storage and transportation of green hydrogen (H2). However, at the point of use, the catalytic dehydrogenation of H18DBT is still limited by mass transport limitations. To address this issue, the dehydrogenation of H18DBT was successfully conducted on Pt/Al2O3-coated foams in both an unstirred tank reactor and a fixed-bed reactor (FBR). A performance comparison between coated foams and pellets in the tank reactor revealed that H2 productivities were 12–59% higher in the foam-based reactor than in the pellet-based reactor. Since the textural properties of the foam-supported and pellet-based catalysts were similar, the higher degree of dehydrogenation (DoD) and H2 productivity achieved by the former were attributed to the geometric properties of the foam structure. Long-term tests performed in the FBR demonstrated the ability of the coated foams to maintain steady activity for >16 h on stream. However, the single-pass DoDs achieved were 34–38%. By recycling the partially dehydrogenated products three times into the FBR, the DoD improved to 63%. The results of this study demonstrated the capabilities of the coated foams in the process intensification of LOHC dehydrogenation reactors.