Carbon black preparation by partial oxidation of spent tyre pyrolysis oil – Influence of temperature, residence time and oxygen to feed ratio.

• Carbon black (CB) was successfully prepared from spent tyre pyrolysis oil (STPO). • CB yield decreases with increasing temperature, residence time and O 2 /Feed ratio. • Operating conditions dictate a trade-off between CB yield and carbon content. • Temperature and O 2 /Feed ratio show strong impact on CB yield and carbon content. • CB_STPO is richer in surface oxygen functionality than heavy residue fraction CB. Preparation of carbon black (CB) by partial oxidation of the spent tyre pyrolysis oil (STPO) and its heavy residue fraction (HRF) was systematically studied using a lab-scale drop tube furnace. The effect of furnace operating temperature (T : 1100 to 1400 °C), residence time (t r : 5 to 60 s) and oxygen to feed ratio (O/F : 174 to 732) on the yield and quality of CB was examined using the response surface methodology (RSM). T was shown to have the most significant influence on CB yield and properties. While the CB yield was also influenced by t r , the quality was more sensitively dependent on T and O/F. The predicted optimal t r and O/F were approximately the same for both feedstocks (60 s and 174, respectively). However, T was higher for the HRF feedstock (1368 °C) than the STPO feedstock (1331 °C) due to the abundance of more viscous heavy hydrocarbons in HRF. Validation experiments under the aforementioned conditions demonstrated the models' ability to predict responses accurately. The CB from both feedstocks had low contents of ash (<0.03%), volatiles (∼0.5%), sulphur (<0.7%), and high carbon (≥95%). The BET surface area and average primary particle size for CB from STPO and HRF were comparable to those of commercial CBs from fossil fuel feedstock. The CB from HRF had a higher carboxyl oxygen functional group (18%) compared to the CB from STPO (∼13%) and commercial CB (<5%). [ABSTRACT FROM AUTHOR]