An Attempt on Using a Regenerated Commercial NiMoS/Al2O3 as a Catalyst for Waste Tyre Pyrolysis

A used commercial sulfided NiMoS/Al2O3 catalyst from the hydrodesulfurization unit of a refinery in Thailand was employed as a catalyst for waste tire pyrolysis since it contains both acid and metal sulphide functions that could potentially benefit cracking and sulphur removal simultaneously. It was regenerated prior to use in a catalytic zone operated at 350 degrees C of the pyrolysis reactor. As a result, as compared to the non-catalytic case, the catalyst gave less long residue with a higher amount of full range naphtha in the tire-derived oil that contained a higher amount of mono-aromatics. Moreover, the oil contained a fewer amount of polar-aromatics as well as less sulphur content. Furthermore, the oils were analyzed for sulphur species by using GC-TOF. The results showed that the oil obtained from sulphided NiMoS/Al2O3 had a higher amount of sulphur-containing molecules in the range of gasoline than the non-catalytic oil. Most of the sulphur-containing molecules found in gasoline, kerosene and gas oil ranges were benzothiophene derivatives such as 3-methybenzothiophene (C9H8S), benzo[b] thiophene, 2,5-dimethyl-(C10H10S), and dibenzothiophene derivatives such as naphtho[2,3-b] thiophene, 4,9-dimethyl-(C14H12S).