A novel bilayer catalyst composed of amorphous silica-alumina (ASA) layer coated on Y zeolite layer is proposed as a fluid catalytic cracking (FCC) catalyst to cause two-stage reactions of pre-cracking and deep-cracking. The bilayer catalyst (Y/ASA) is compared with the usual mixed one (ASA+Y), in catalytic cracking of a feed composed of 1,3,5-triisopropylbenzene and naphthalene. The two catalyst representations were prepared by applying layers of Y zeolite and ASA or both on inert monolith supports. Catalytic cracking experiments were carried out at 300, 350 and 400 oC. Compared to Y+ASA, Y/ASA yielded about 33% and 46% more benzene and toluene, respectively, and 18% less coke in the catalytic cracking at 350 °C. The coke of Y/ASA was less refractory than that of Y+ASA as burnt at lower temperatures, while emitting less carbon monoxide in regeneration. Y/ASA configuration shows promising features as FCC catalysts for increased bottoms cracking and suppressed coking.
Costa AF, Cerqueira HS, Sousa-Aguiar EF, Ludvig MM, Performance of FCC catalysts prepared with sub-micron Y zeolite, in: M. C. E. van Steen, L. H. Callanan (Eds.) Studies in Surface Science and Catalysis, Elsevier, 2296 (2004).