Catalytic pyrolysis of waste tire over KL-based catalysts: double beds of KL and Y zeolites

Abstract

Catalysts can assist in waste tire pyrolysis for the production of valuable products. A new type of acid-base catalysts can play an important role on modifying the product yields and the compositions of hydrocarbon products. Therefore, the advantages of high isomerization (KL), aromatization (Pt/KL), and ring opening (Pt/Y) activities could be simultaneously taken by using a combination of these catalysts in a pyrolysis reactor. The influence of the catalyst mixing between acid (Y) and basic (KL) zeolites and the packing sequence in the reactor were studied with the expectation of producing molecules of higher valuable products. The ratio of the two zeolites was varied from 0.25 to 1.0 with a fixed 1% wt of Pt loaded by using incipient wetness impregnation. From the results, it was clear that the yields of light olefins and cooking gas received from the physical mixtures (Y + KL) were higher than those of the catalytic pyrolysis with the pure zeolites. Especially, the mixture at the ⊘kl = 0.25 gave the highest activity on light olefins and cooking gas production. Moreover, it was found that Pt/KL packed in the first layer with Pt/Y on the second. layer at ⊘pt/KL = 0.25 produced the highest saturated hydrocarbon content; thus, this combination can be considered to be a promising catalyst for gas oil production. Furthermore, the single Pt/KL bed gave the highest aromatic content in the maltenes fraction. Therefore, the octane number of its oil is expected to be highly improved.