Abstract
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•Catalytic and non-catalytic pyrolysis of tire waste was carried out at pilot-scale.•Non-catalytic pyrolysis produced highest liquid oil as compared to catalytic pyrolysis.•Natural zeolite, zeolite (H-SDUSY), Al2O3 and Ca(OH)2 catalysts were used.•Use of various catalysts improved the quality of liquid oil.•Oil from both processes mainly contained aromatic with some aliphatic compounds.
This study aims to examine the effect of various advanced catalysts on tire waste pyrolysis oil using a small pilot-scale pyrolysis reactor with a capacity of 20L. The catalytic pyrolysis with activated alumina catalyst produced maximum liquid oil (32wt.%) followed by activated calcium hydroxide (26wt.%), natural zeolite (22wt.%) and synthetic zeolite (20wt.%) catalysts, whereas liquid oil yield of 40% was obtained without catalyst. The gas chromatography-mass spectrometry results confirmed the pyrolysis liquid oil produced without catalyst consist of up to 93.3% of mixed aromatic compounds. The use of catalysts decreased the concentration of aromatic compounds in liquid oil down to 60.9% with activated calcium hydroxide, 71.0% with natural zeolite, 84.6% with activated alumina, except for synthetic zeolite producing 93.7% aromatic compounds. The Fourier-transform infrared spectroscopy data revealed that the mixture of aromatic and aliphatic hydrocarbon compounds were found in all liquid oil samples, which further confirmed the gas chromatography results. The characteristics of pyrolysis liquid oil had viscosity (1.9cSt), density (0.9g/cm3), pour point (–2°C) and flash point (27°C), similar to conventional diesel. The liquid oil had higher heating values, key feature of a fuel, in the range of 42–43.5MJ/kg that is same to conventional diesel (42.7MJ/kg). However, liquid oil requires post-treatments, including refining and blending with conventional diesel to be used as a transport fuel, source of energy and value-added chemicals.