ZSM-5 zeolites are used as additives in commercial Fluidised Catalytic Cracking (FCC) units to promote the conversion of olefinic gasoline fractions to LPG olefins. In this role they form a key link in the supply chain of these important feedstocks and improving their yield is a favoured route for meeting the current shortage of propene in the global petrochemicals market. The structure and acidity of the ZSM-5 are known to change over its catalytic lifetime due to steam dealumination of the framework. These changes are known to result in significant changes to the catalysts activity and selectivity and to ultimately play a role in initiating catalyst deactivation. This proposal and a parallel proposal on MAPS aims to understand how the interactions of steamed ZSM-5 with propene and a model gasoline-range olefin (1-octene) differ from those previously observed for the fresh zeolite.
