Upgrading of Waste Tyre-Derived Oil from Waste Tyre Pyrolysis over Ni Catalyst Supported on HZSM-5 Zeolite

Abstract

The catalytic pyrolysis of waste tyre was investigated using Ni-doped HZSM-5 zeolite as a catalyst in a bench-scale reactor ramped from room temperature to 500 °C (pyrolysis zone) and 350 °C (catalyst bed), aiming to improve the quality of tyre-derived oil in terms of sulphur reduction and enhancement of valuable petrochemical production. 5 wt% of nickel was introduced on HZSM-5 zeolite using incipient wetness impregnation, and characterised using XRD, surface area analyser, and XPS. Gaseous products were analysed by GC-FID. The GCxGC-TOF/MS and SIMDIST-GC were used for analysis of pyrolysis oil. The sulphur content in tyre-derived oil was determined by S-analyser. The introduction of metallic nickel on HZSM-5 zeolite significantly changed textural properties, also modified the catalytic behaviour. When compared to parent HZSM-5 zeolite, Ni/HZSM-5 catalyst significantly improved gasoline and kerosene production in waste tyre-derived oil, whereas the heavy fractions, such as gas oil and light vacuum gas oil, drastically decreased. In addition, Ni doping drastically reduced sulphur contents in tyre-derived oil by 29.2%. Benzothoiphenes, dibenzothiophenes, and naphthothiophene were the sulphur species that significantly decreased. Furthermore, with Ni loading, the production of cumene, ethylbenzene, toluene, and mixed xylenes in oil was also enhanced. These results indicated Ni/HZSM-5 was a promising catalyst for enhancement of tyre-derived oil quality.