Effects of Fe supported on zeolites on structures of hydrocarbon compounds and petrochemicals in waste tire-derived pyrolysis oils

Abstract

Waste tire, a hydrocarbon-based material, exhibits potential to be used for petrochemical production. Valuable chemicals such as benzene, toluene, xylenes, and styrene for instances have been observed in pyrolytic oils. Furthermore, sulfur compounds causing the low quality of oil and the environmental pollutant are also absolutely found. Iron catalysts appear to be economically feasible in catalytic fields. Especially, iron can be used to substitute the noble metal promoters in the pyrolysis of waste tire due to its good activities on hydrogenation and ring opening reactions. This study therefore investigates the effects of iron supported on zeolites (HMOR, HBeta, HZSM-5, and KL) on structures of hydrocarbon compounds and petrochemicals in waste tire-derived oils. Fe-promoted zeolites were prepared by incipient wetness impregnation technique with the fixed amount of Fe at 5wt.%. The products and catalysts were characterized by using GC, SIMDIST-GC, GC×GC-TOF/MS, elemental analyzer, XRD, and SAA. The results showed that the introduction of 5%Fe on zeolites can enhance the cracking ability of products. Namely, the gas yield increased, at the expense of liquid yield. In addition, light hydrocarbon gases increased in accordance with the reduction of heavier gases. Moreover, the light fractions in oil also increased with using iron-loaded zeolites. Moreover, olefins and naphthenes tended to decrease, but mono-aromatics increased with using all 5%Fe-loaded zeolites. Consequently, the reduction of di- and poly-aromatics was observed for all Fe-promoted catalysts, except 5%Fe/HBeta. Using 5%Fe-loaded zeolites, except 5%Fe/HBeta resulted in the increasing yields of petrochemicals such as benzene, toluene, ethylbenzene, xylenes, and styrene, for examples, in oil. Furthermore, 5%Fe-loaded catalysts resulted in the reduction of sulfur in oil. Dibenzothiophenes and benzothiazoles were the sulfur compounds in oil that decreased with the presence of 5%Fe, except 5%Fe/HZSM-5, whereas benzothiophenes tended to decrease.