Effects of process factors on extrusion of hierarchically porous ZSM-5 zeolite

The extrusion of hierarchically porous ZSM-5 zeolite was studied and three important process factors, i.e., the content of pseudo boehmite as binder, content of nitric acid as peptizer, and extrusion speed, were examined. The mechanical properties of the shaped ZSM-5 were investigated by Weibull statistics and the textural properties were studied by nitrogen adsorption/desorption. Results revealed that the extrusion speed affected the mechanical reliability but had less effect on the textural properties. However, the addition of pseudo boehmite and nitric acid not only improved the mechanical reliability but also brought better pore structure. There is, therefore, a great possibility of improving the mechanical reliability and pore structure by optimizing the extrusion conditions. It is shown that the optimal properties of the shaped ZSM-5 could be obtained when 33 wt% pseudo boehmite, 13 wt% nitric acid and 50 r/min extrusion speed were used. The optimized extrusion of hierarchically porous ZSM-5 zeolite might have true industrial potential in the near future. (C) 2019 Elsevier B.V. All rights reserved.