Steam Deactivation Kinetics of Zeolitic Cracking Catalysts

Chester, Arthur W.; Stover, William A.

doi:10.1021/i360064a005

Cited by 17 publications

(1 citation statement)

References 3 publications

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“…This same approximation could be applied to other zeolites having high framework Si/Al ratios, suggesting that kinetic studies of crystallinity loss in other zeolites could be informative. However, general literature searches on the kinetics of zeolite collapse, as well as a citation search on Pine, yield just a few papers of potential relevance. − Among these, some work − modeled catalyst activity not zeolite properties, while others explored kinetic synergy between Na and V , but did not evaluate activation energies for zeolite or Si T collapse or nonidealities in these kinetics. The lack of literature on the kinetics of hydrothermal Si T collapse is doubtless due in part to the fact that Si T is not catalytically active.…”

Section: Introductionmentioning

confidence: 99%

Continuous Age Distribution Method for Catalytic Cracking 2. Understanding Nonidealities

Stockwell

2018

Ind. Eng. Chem. Res.

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In a previous paper, we introduced a novel steam deactivation method, which could in principle reproduce many features of refinery FCC equilibrium catalysts. However, nonideal zeolite decay kinetics had prevented full realization of the potential of the method. Further analysis now shows those kinetic deviations were due to a ubiquitous 10–20% of metastable framework Si in zeolite Y, which is already familiar via the zeolite ultrastabilization process. Unexpectedly high framework Si collapse rates have also been found above 870 °C, but these may not be relevant to the refinery. The effects of these nonidealities can be appropriately excluded by collapsing metastable Si in a mild presteaming at 732 °C and/or by elongating catalyst deactivation time in the method. Variations of the method are then used to demonstrate that the 0–5th age percentile of refinery equilibrium catalyst does substantially contribute to coke and hydride transfer, and that presteaming can be used to systematically effect changes in zeolite mesoporosity, which in turn have a striking linear effect on cracking yields.

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