Novel extruded fixed-bed MTO catalysts with high olefin selectivity and high resistance against coke deactivation

作者：Freiding Jens; Kraushaar Czarnetzki Bettina^*

来源：Applied Catalysis A: General , 2011, 391(1-2): 254-260.

DOI：10.1016/j.apcata.2010.05.035

• MTO (methanol to olefins)
• ZSM-5
• Coke deactivation
• Extrusion
• Aluminium phosphate

This report describes the catalytic performances of AlPO(4)/ZSM-5 extrudates in comparison to conventional alumina- and silica-bound extrudates in the fixed-bed MTO (methanol to olefins) conversion. The novel AlPO(4)/ZSM-5 extrudates are produced with an aluminium phosphate binder which undergoes a phase transition into an AlPO(4)-tridymite phase upon calcination of the greenbodies. The finished AlPO(4)/ZSM-5 extrudates are macroporous and mechanically very stable. In contrast to alumina, this novel matrix does not exhibit catalytic self-activity, and it does not release aluminium which is incorporated in the zeolite lattice. At temperatures above 400 degrees C, AlPO(4)/ZSM-5 extrudates show superior activity, propylene selectivity and stability. The coke deactivation of AlPO(4)/ZSM-5 extrudates can further be reduced dramatically, if a pre-reactor is installed upstream, where an equilibrium mixture of dimethyl ether (DME), methanol and water (X(MeOH) = 87.7% at 275 degrees C) is produced. In contrast, the insertion of the DME pre-reactor has no significant effect on the coke resistance when extrudates with alumina- or silica-matrices are used.

• 出版日期2011-1-4