Tire pyrolysis oil (TPO) is a complex mixture of hydrocarbons spanning a wide boiling point range. Due to its complexity, direct implementation of TPO to combustion applications has been challenging. Distillation is a simple method for grouping similar compounds, based on their volatility, thereby facilitating further upgrading and use. In this work, TPO was distilled at atmospheric pressure into different fractions (light, low-middle, high-middle, and heavy), and the structural characteristics of each fraction were explored. Therefore, advanced analytical techniques such as GC–MS, APPI FT-ICR MS and 1H and 13C NMR were utilized. For the light fraction, the GC–MS revealed a significant presence of benzene, toluene, and xylene, as well as limonene. From the APPI FT-ICR MS results, the low-middle, high-middle, and heavy fractions were classified into a number of molecular classes. Among these, pure hydrocarbons (HC), hydrocarbons containing one sulfur atom (S1), hydrocarbons containing two oxygen atoms (O2), etc. Here, HC and S1 were found to be the most abundant molecular classes in all fractions. Finally, a structural analysis of the functional groups present in each TPO fraction was conducted by 1H and 13C NMR. Average molecular parameters (AMPs), such as the number of aromatic, naphthenic, and olefinic carbons/hydrogens, were determined. In addition, derived AMPs, such as the aromaticity factor (fa), C/H paraffinic, C/H aromatic, etc., were calculated. Fractionation by distillation resulted in concentration of both the sulfur and aromatic compounds in the heaviest fraction. In this manner, effective application and upgrading strategies could be individually designed for each fraction.
Bibliographical noteKAUST Repository Item: Exported on 2021-01-11
Acknowledgements: F. Campuzano wishes to express his gratitude to COLCIENCIAS for the PhD scholarship 757-2016 and to the Clean Combustion Research Center at the King Abdullah University of Science and Technology for the research internship. This research used the resources of the Core Labs of KAUST.