Catalytic fast pyrolysis of waste truck-tire to aromatics production over metal-modified USY catalysts

Abstract

This work aimed to investigate the effect of several metal-modified (Fe, Co, Ni, Cu, Zn) USY catalysts on the high-value aromatic production from fast pyrolysis of waste truck-tire in an infrared-heated fixed-bed reactor. The relationship between the physical and chemical properties of the catalyst and the production of light aromatic hydrocarbons was revealed based on comprehensive catalyst characterization and catalytic reaction test results, guiding the selection of the optimal modified metal and loading amount. Among all the investigated metal-modified USY catalysts, 1%Cu/USY catalyst exhibited the best aromatics production capacity, with a relative content of monoaromatics of 63.70% and a yield of specific aromatics of 42.92 mg/g, both of which were significantly greater than those obtained over the parent USY catalyst (58.73% and 27.23 mg/g). The introduced copper species provided abundant Lewis acid sites and cooperated with Brønsted acid sites to promote the cracking, dehydrogenation, and aromatization reactions to reach a specific balance, thus enhancing catalytic performance. However, when the loading amount exceeded 1 wt%, Cu species aggregate on the surface of the zeolite, leading to pore blockage and surface area reduction. High Cu loading amounts could also result in excessive acidity, which could cause excessive cracking of volatiles and lower aromatics selectivity. In addition, the 1%Cu/USY catalyst exhibited excellent reusability in the reaction/regeneration cycles. This work demonstrates the feasibility of producing light aromatics via WTT catalytic fast pyrolysis over Cu-modified USY catalyst, which provides new ideas for the chemical recovery of waste tires.