Conversion of methanol into light olefins over ZSM-11 catalyst in a circulating fluidized-bed unit

摘要

Methanol conversion and the reaction pathway were investigated in a pilot-scale circulating fluidized-bed (CFB) unit over hierarchical ZSM-11 catalyst. Experimental results indicated that ZSM-11 catalyst was highly resistant to external coke due to the formation of mesopores. Elevated temperatures favored the production of propylene and butylene and decreased the yield of ethylene. Additionally, no direct relations were shown between the formation of ethylene and other products under different pressures, suggesting that ethylene was a primary product produced at the initial of the reaction. Methylation-cracking and oligomerization were verified as the main reaction pathway for the formation of C (3) (+) alkenes., Methylation and oligomerization of olefins were dominated under high methanol partial pressure and consequently responsible for the production of higher olefins, while the b-scission of C (7) (=) for propene and butylene, and C (8) (=) for butylene were enhanced at low methanol partial pressure.