Songbo He, Thomas Sjouke Kramer, Frederike Gerda Hiltje Klein, Anshu Chandel, Zhuorigebatu Tegudeer, Andre Heeres, Chuncheng Liu, Evgeny Pidko, Hero Jan Heeres*

Applied Catalysis A: General,629, 118393

https://doi.org/10.1016/j.apcata.2021.118393

ABSTRACT: 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.

摘要：为研究Al₂O₃粘结剂对催化剂性能的影响，本文在连续固定床反应器中考察了甘油在成型H-ZSM-5/Al₂O₃（60/40 wt%）催化剂上催化转化为芳烃（GTA，如苯、甲苯和二甲苯，即BTX）的反应过程。实验在N₂氛围、550 °C、甘油空速（WHSV）为1 h⁻¹及常压条件下进行。对使用后的H-ZSM-5/Al₂O₃催化剂在680 °C进行氧化再生，并完成总计5次反应-再生循环。表征结果表明，Al₂O₃粘结剂的添加不影响催化剂体系的比表面积和结晶度，但显著增加了总孔体积（尤其是介孔）和总酸量（以路易斯酸为主）。与纯H-ZSM-5相比，H-ZSM-5/Al₂O₃（60/40 wt%）催化剂的寿命明显延长（8.5 h vs. 6.5 h），BTX总产率显著提高（710 vs. 556 mg/g H-ZSM-5）。此外，Al₂O₃粘结剂的引入延缓了催化剂的不可逆失活：经历3次再生后，催化剂性能仍与新鲜催化剂相当；但经过4次再生后，由于总孔体积、结晶度、酸量（尤其是布朗斯特酸）以及Al₂O₃粘结剂介孔结构的减少，出现部分不可逆失活。本研究证明，使用合适的粘结剂可显著提升H-ZSM-5基催化剂在GTA反应中的稳定性和可重复使用性。