Zeolite-induced matrix effects

Table lb. Zeolite Induced Matrix Effects (for n< 8) in n(W03)-Na56Y Compared With n(W03)-H56Y... 

It is quite challenging to rmderstand in what way the zeolite influences the metal compared to other supports. The electronic changes that could be induced by the pore system are quite subtle and metal particle size effects may overrule these changes [200]. hi comparison to metal-support interactions on macroporous oxides, the interaction between metal particles and the supporting zeolite matrix seems more pronounced. This may be because the metal particles interact with the zeolite lattice over a substantial fraction of their surfece. It has also been suggested that in addition to the intrinsic electronic effects due to the small size of the metal particles in the zeolite cage, a modification of the electronic structure of the metal by the acidic zeolite framework has to be considered [201,202]. 

In this paper we present our results on a study ofthe deactivation and characterisation of FCC catalysts, together with product yields at realistic coke levels (0.5 to 1.0%), that are typically found on FCC catalysts during industrial operation. In particular, the effect of quinoline and phenanthrene as additives to the n-hexadecane feedstock has been studied at two concentration levels and the relative roles ofthese additives as catalyst poison and coke inducer are discussed. A further aspect investigated is the influence of catalyst formulation. Pure zeolites are seldom used as FCC catalysts instead, catalysts comprise a number of components, which apart from the zeolite, may include matrix, binder and clay. In the present work, catalyst formulations ranging fi"om 100% matrix to 100% zeolite have been examined and the influence ofthe various catalyst compositions on product distribution and coke formation is assessed. 

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