Catalytic conversion of glycerol to bio-based aromatics using H-ZSM-5 in combination with various binders

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.