Pyrolysis and Oxidation of Waste Tire Oil: Analysis of Evolved Gases

Abstract

Valorization of waste such as waste tires offers a way to manage and reduce urban waste while deriving economic benefits. The rubber portion of waste tires has high potential to produce pyrolysis fuels that can be used for energy production or further upgraded for use as blend fuel with diesel. In the preset work, waste tire oil (WTO) was produced from the pyrolysis of waste tires in an electric heating furnace at 500–550 °C in the absence of oxygen. Pyrolysis (in nitrogen) and oxidation (in air) of the obtained WTO sample were then performed in a thermogravimetric (TG) furnace that was connected to a Fourier transform infrared cell where the evolved gases were analyzed. The WTO sample was heated up to 800 °C in the TG furnace where the temperature of the sample was ramped up at three heating rates, namely, 5, 10, and 20 °C/min. The TG mass loss and differential thermogravimetric mass loss plots were used to analyze the thermal degradation pathways. Kinetic analysis was performed using the distributed activation energy model to estimate the activation energies along the various stages of the reaction. The pollutant gases, namely, CO 2 , CO, NO, and H 2 O, formed during WTO oxidation were evaluated by means of the characteristic infrared absorbance. The functional groups evolved during pyrolysis, namely, alkanes, alkenes, aromatics, and carbonyl groups, were also analyzed. The obtained information can be used for the better design of gasifiers and combustors, to ensure the formation of high-value gaseous products while reducing the emissions. The utilization of waste tires by producing pyrolysis oils thus offers a way of tackling the menace of waste tires while acting as a potential energy source.

Investigation of Chemical, Physical, and Tribological Properties of Pyrolysis Oil Derived from End-of-Life Tires (ELTs) against Conventional Engine Oil

“…In terms of the sulfur content, the engine oil contained 0.31%, while the pyro-oil contained 0.72%. The sulfur content agrees with past findings in thermal and catalytic pyrolysis for pyro-oil [48,52] and for used and fresh engine oil [55]. The high sulfur content in pyro-oil compared with engine oil is attributed to the tire's vulcanization process during the manufacturing of tires.…”

“…This shows that the aromaticity of the pyro-oil is higher than that of the conventional engine oil tested. This was also expected with ELT pyro-oils since they are mainly made of monoaromatics (in particular) and aromatic compounds (in general) such as limonene and isoprene [35,[48][49][50]. It is also noteworthy to indicate that, at 1710 cm −1 , there was a clear peak in the pyro-oil sample associated with carbonyl groups (C=O in stretching) that was not clearly visible in the engine oil.…”

Assessment of the Environmental Impact of Solid Oil Materials Based on Pyrolysis Oil

“…Another distinctive peak from bending vibrations of scissor C-H bonds is found at 1455 cm −1 . The peak at 1705 cm −1 comes from stretching vibrations of C=O bonds, characteristic of aldehydes and ketones [47]. Bending vibrations of C-H bonds present in aromatic compounds occur at 1033 cm −1 .…”