Fuel and Chemical Properties of Waste Tire Pyrolysis Oil Derived from a Continuous Twin-Auger Reactor

Abstract

Tire pyrolysis oil (TPO) is a complex mixture of hydrocarbons, and it is one of the useful fractions obtained from the pyrolysis of waste tires (WT). As a result of its high energy density (HHV ~ 43 MJ/kg), TPO use as a fuel in combustion systems is a promising approach for recycling WT. However, fundamental fuel characteristics and combustion properties of TPO are still unexplored, which stand as a bottleneck for potential applications.This work pursues a comprehensive understanding of the structural characteristics of a TPO produced in a labscale twin-auger reactor as a first step towards defining applications and upgrading strategies. Therefore, advanced analytical techniques such as Fourier Transform -Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS), and 1 H and 13 C Nuclear Magnetic Resonance (NMR) spectroscopy were utilized. In addition, we also present the characterization of a TPO obtained from adding CaO to WT, as a low-cost catalytic material for its in-situ upgrading, herein named TPO [CaO]. FT-ICR MS results revealed the significant presence of pure hydrocarbons (HC) (HC(TPO) = 74.9 % and HC(TPO[CaO]) = 78.6 %) and hydrocarbons containing one sulfur atom (S1) (S1(TPO) = 14.3 % and S1(TPO[CaO]) = 13.9 %). HC compounds were found mainly in the form of tri-aromatics (26 %), tetra-aromatics (13 and 15 %), and penta-aromatics (22 and 30 %), while S1 compounds in the form of dibenzothiophene (31 %) and benzonaphthothiophene (34 %). The resolved compounds by means of FT-ICR 2 MS exhibited an average double bond equivalent (DBE) number of 11.3 and 12.2 for TPO and TPO[CaO], respectively. These high DBE values were indicators of the significant presence of condensed aromatic structures. 1 H NMR analysis showed that hydrogen atoms in methylene (CH2), methyl (CH3), and naphthenic groups, as well as hydrogen atoms in aromatic structures make up more than 80 % of both fuels. Similarly, carbon atoms in paraffinic groups (both CH2 and CH3) and protonated carbons in aromatic rings together form more than 50 % of the carbon atoms in TPO and TPO [CaO]. The information reported in this work provides new insights into the structural characteristics of the TPO obtained in promising technology as the twin-auger reactor for its use as a fuel, as well as for the design of upgrading strategies.

Predicting Ignition Quality of Oxygenated Fuels Using Artificial Neural Networks

“…Therefore, expressing a fuel's chemical composition by means of functional groups enables us to capture its chemical nature and predict its DCN. 1 H NMR spectroscopy is an advanced analytical technique that can qualitatively and quantitatively estimate the fuels functional groups as shown in a number of works [79][80][81][82][83][84]. Oxygenated fuels containing alcohol OH and ether O functionalities can be divided into eight functional groups namely paraffinic CH3 groups, paraffinic CH2 groups, paraffinic CH groups, olefinic -CH=CH2 groups, naphthenic CH-CH2 groups, aromatic C-CH groups, alcoholic OH groups and ether O groups and serve as inputs to develop a DCN model.…”

Catalytic selective ring opening of polyaromatics for cleaner transportation fuels

“…54 Approximately 1 billion waste tires are produced globally per annum; 55 pyrolysis oil derived from tire waste, in precommercial production by companies such as Southern Oil Refining, may contain 460% polyaromatics. 56 Note that the production of diesel range hydrocarbons varies with pyrolysis conditions, with higher temperatures favouring polyaromatic hydrocarbons. 49 Diesel fuels derived directly from LCO or waste pyrolysis oils are either low yielding or poor quality due to their high aromatic content, and hence require improved upgrading technologies to remove naphthenics.…”

Review on Evolved Gas Analysis Mass Spectrometry with Soft Photoionization for the Chemical Description of Petroleum, Petroleum-Derived Materials, and Alternative Feedstocks

“…This waste made of natural and synthetic rubber, carbon black, textile material, steel, sulfur, and additives can be thermochemically converted (pyrolyzed), generating tire pyrolysis oils having a comparable calorific value to petroleum . Thermal degradation of waste tires leads to broad and complex chemical composition, dominated by hydrocarbons, classically requesting in-depth characterization. , Interestingly, also PAHs, from the cyclization and aromatization of the thermal degradation product butadiene, and amines as well as thiophenes, from additives and manufacturing accelerators, were found . Prospectively, studying the chemical composition of this alternative feedstock will be of high interest for evolved gas analysis soft photoionization mass spectrometry in the framework of a circular economy, particularly taking into account the vital field of co-pyrolysis together with other feedstocks, such polymers and biomass.…”