The catalytic conversion of glycerol to aromatics (GTA, e.g., benzene, toluene, and xylenes, BTX) over a shaped H-ZSM-5/Al₂O₃ (60/40 wt%) catalyst was investigated in a continuous fixed-bed reactor to study the addition of the Al₂O₃ binder in the catalyst formulation on catalyst performance. The experiments were performed under N₂ at 550 °C, a WHSV of glycerol (pure) of 1 h⁻¹, and atmospheric pressure. The spent H-ZSM-5/Al₂O₃ catalysts were reused after an oxidative regeneration at 680 °C and in total 5 reaction-regeneration cycles were performed. Catalyst characterization studies show that the addition of the Al₂O₃ binder does not affect the surface area and crystallinity of the formulation, but increases the total pore volume (mesopores in particular) and total acidity (Lewis acidity in particular). The H-ZSM-5/Al₂O₃ (60/40 wt%) catalyst shows a considerably prolonged catalyst life-time (8.5 vs. 6.5 h for H-ZSM-5), resulting in a significant increase in the total BTX productivity (710 vs. 556 mg g⁻¹ H-ZSM-5). Besides, the addition of the Al₂O₃ binder retards irreversible deactivation. For instance, after 3 regenerations, catalyst performance is comparable to the fresh one. However, after 4 regenerations, some irreversible catalyst deactivation occurs, associated with a reduction in total pore volume, crystallinity, and acidity (Brønsted acidity in particular), and meso-porosity of the Al₂O₃ binder. This study shows that both the stability and reusability of H-ZSM-5-based catalysts for GTA are remarkably enhanced when using a suitable binder.

The use of H-ZSM-5 with various binders (Al₂O₃, SiO₂, and kaolinite, 10 wt% on catalyst formulation) for the catalytic conversion of glycerol to bio-based aromatics (GTA) was investigated in a continuous bench-scale unit at a pyrolysis temperature of 450 °C, catalytic upgrading temperature of 500 °C, WHSV of pure glycerol of 1 h⁻¹, and atmospheric pressure, and their performance was compared to H-ZSM-5 (SiO₂/Al₂O₃ molar ratio of 28). The latter gave a peak BTX carbon yield of ca. 31.1C.%, a life-time of ca. 220 min, and a total BTX productivity of ca. 312 mg BTX g⁻¹H-ZSM-5. The introduction of binders affects catalyst performance, which is the most profound and promising for the H-ZSM-5/Al₂O₃ catalyst. It shows a prolonged catalyst life-time of ca. 320 min and a higher total BTX productivity of ca. 518 mg BTX g⁻¹H-ZSM-5, compared to the H-ZSM-5 without a binder. Catalyst characterization studies show that the addition of the binder does not have a major effect on the specific surface area, total pore volume, and total acidity. Other relevant properties were affected, though, such as micropore volume (SiO₂), a reduced Brønsted acidity (Al₂O₃, and SiO₂), and reduced crystallinity (SiO₂). Coke formation causes severe catalyst deactivation, ultimately leading to an inactive catalyst for BTX formation. Catalyst characterization studies after an oxidative regeneration showed that the textural properties of the regenerated catalysts were close to those of the original catalysts. However, some dealumination of H-ZSM-5 occurs, resulting in decreased crystallinity and acidity, causing irreversible deactivation, which needs attention in future catalyst development studies.