The resistance to coking and metal deposition from heavier crude feedstocks is important to a fluid catalytic cracking (FCC) catalyst. The catalytic cracking of
n-hexadecane (
n-C
16H
34) as a model compound was studied on the ultrastable Y zeolite (USY) catalysts with nanoporous (
np, 5-50 nm pore diameter) Al
2O
3. A combination of two
np Al
2O
3 types with well controlled pore size (7 nm or 35 nm) was employed as binder and matrix. The catalyst made with the matrix from the combination of the two pore sizes, with an average pore size of around 14 nm, exhibited higher cracking activity and lower rate of degradation by coking, similar to the catalyst with the single matrix pore size of 14 nm. A USY zeolite catalyst fabricated with only the small pore size
np Al
2O
3 exhibited better resistance to hydrothermal regeneration under model conditions than a catalyst with the large pore size
np Al
2O
3. A catalyst partly containing small pore size
np Al
2O
3 exhibited better resistance to hydrothermal regeneration after intentional deposition of vanadium than a catalyst made of the small pore size
np SiO
2. Therefore, the small pore size
np Al
2O
3 has functions to protect the zeolite component and its activity, against both of high temperature steam and vanadium species, by binding on the zeolite surface and trapping the vanadium which easily moves over
np SiO
2 during regeneration. Furthermore, it was clarified that the large pore size
np Al
2O
3 in the mixed matrix can also act as a trapping site for Ni deposition to reduce coking with hydrogen generation on the deposited Ni and protection of the zeolite component activity.
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