Activation Energy Of Pyrolysis Research Articles

Influence Mechanism of Water-Soluble Sodium on Zhundong Coal Pyrolysis.

An inherent water-soluble sodium-loaded coal sample was prepared using crown ether for this study. The pyrolysis process of an inherent water-soluble sodium-loaded coal sample and a water-soluble sodium compound-loaded coal sample was researched by thermogravimetric analysis (TGA). Also, the pyrolysis kinetics of the coal samples were analyzed and researched by the distributed activation energy model (DAEM). The results show that the inherent water-soluble sodium is mainly concentrated on coal particles, which further aggravates the degree of the pyrolysis reaction. The presence of sodium can promote the weight loss of coal samples in the preliminary stage of pyrolysis and the thermal condensation stage, block the escape of volatile matter during the main pyrolysis period, and inhibit the process of graphitization of char. The activation energy of pyrolysis increases with the carbon conversion rate, and the presence of sodium can reduce the activation energy under the same carbon conversion rate.

Pyrolysis mechanism study of n-heptane as an endothermic hydrocarbon fuel: A reactive molecular dynamic simulation and density functional theory calculation study

The pyrolysis of endothermic hydrocarbon fuel with high heat sink can reduce the surface temperature of engines and aircraft fuselage. The pyrolysis mechanism of n-heptane as a model compound for endothermic hydrocarbon fuel was investigated by using ReaxFF reactive molecular dynamic simulations and density functional theory calculations. The results showed that the breakage of CC bonds of n-heptane were easier than that of CH bonds, in which the cleavage of C2C3 bond is the easiest to generate C2H5 and C5H11 radicals. Temperature has a significant effect on the pyrolysis process of n-heptane, and the increase of temperature will accelerate the pyrolysis of n-heptane and promote the formation of pyrolysis products. The pre-exponential factor and apparent activation energy of the n-heptane pyrolysis were 5.4456 × 1014 s−1 and 231.3 kJ·mol−1, respectively.

Pyrolysis of Methyl Ricinoleate: Distribution and Characteristics of Fast and Slow Pyrolysis Products.

A stable temperature site and the speed of heating the feedstocks play a key role in pyrolysis processes. In this study, the product distribution arising from pyrolysis of methyl ricinoleate (MR) at 550 °C with low and high heating rates was first studied by pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS). The results show that fast pyrolysis of MR favored the production of undecylenic acid methyl ester (UAME) and heptanal (HEP). Density functional theory (DFT) calculations were employed to reveal the UAME and HEP formation process from pyrolysis of MR. The bond dissociation energies (BDEs) of C–C bonds in MR showed that the C11–C12 bond is the weakest. This suggests that UAME and HEP are two major products. The process of slow and fast MR pyrolysis was the dehydration-first and the pyrolysis-first trend, respectively. The calculated activation energies of MR pyrolysis to UAME and HEP and MR dehydration to 9,12-octadecadienoic acid methyl ester were 287.72 and 238.29 kJ/mol, respectively. The much higher product yields obtained in the fast pyrolysis reactors than those from conventional tubular reactors confirmed the proposed process.

Pyrolysis Behaviors and Residue Properties of Iron-Rich Rolling Sludge from Steel Smelting.

Iron-rich rolling sludge (FeRS) represents a kind of typical solid waste produced in the iron and steel industry, containing a certain amount of oil and large amounts of iron-dominant minerals. Pyrolysis under anaerobic environment can effectively eliminate organics at high temperatures without oxidation of Fe. This paper firstly investigated comprehensively the pyrolysis characteristics of FeRS. The degradation of organics in FeRS mainly occurred before 400 °C. The activation energy for pyrolysis of FeRS was extremely low, ca. 5.44 kJ/mol. The effects of pyrolytic temperature, atmosphere, heating rate, and stirring on pyrolysis characteristics were conducted. Commonly, the yield of solid residues maintained around 85 wt.%, with approximately 13 wt.% oil and 2 wt.% gas. Due to the low yield of oil and gas, their further utilization remains difficult despite CO2 introduction which could upgrade their quality. The solid residues after pyrolysis exhibited porous properties with co-existence of micropores and mesopores. Combined with the high content of zero-valent iron, magnetic property, hydrophobic characteristic, and low density, the solid residues could be further utilized for water pollution control and soil remediation. Moreover, the solid residues were suitable for sintering to recover valuable iron resources. However, the solid residues also contained certain heavy metals, such as Cd, Cr, Cu, Ni, Pb, and Zn, which might cause secondary pollution during their utilization. In particular, the toxic Cr possessed high content, which should be treated with detoxification and removal. This paper provides fundamental information for pyrolysis of FeRS and utilization of solid residues.

Synthesis and flame inhibition efficiency of a novel Fe-based metal complex with phosphorus-containing structure

Owing to the increased depletion risk and cost of phosphate mines, the demand for low phosphorus or ecological phosphorus flame inhibitor is increasing. This study reports an experimental exploration of the combustion inhibition efficiency of bio-based transition metal complex materials containing iron and phosphorus, namely, iron @ phosphorus complex (Fe-PMC). The aim is to develop a new type of flame inhibitor with an iron-phosphorus interaction effect to replace pure phosphorus extinguishing agents. The synthesis of Fe-PMC was characterized by Fourier-transform infrared spectroscopy, X-Ray diffraction, X-ray photoelectron spectroscopy and Scanning electron microscope. The Fe-PMC (ⅰ) is the mesh porous structure connected by the accumulation of small particles, (ⅱ) is an amorphous structure with many binding sites exposed and excellent interface compatibility, (ⅲ) contains no chloride ions. Suppression tests and thermogravimetric measurements indicate that (ⅰ) Fe-PMC has a higher combustion inhibition ability than MIL-53 containing only iron, especially at low concentrations, (ⅱ) Fe-PMC reduces the laminar flame velocity of cellulose, (ⅲ) Fe-PMC greatly reduces flame temperature. The activation energy (E), pre-exponential factor (A) and char yield (Y) of cellulose pyrolysis were determined by kinetic analysis. It concluded that MIL-53 and Fe-PMC produce combustion inhibition mainly in the solid phase. These findings will contribute to the development of a flame inhibitor with low or no phosphorus and better performance.

Study on the Staged and Direct Fast Pyrolysis Behavior of Waste Pine Sawdust Using High Heating Rate TG-FTIR and Py-GC/MS.

To understand the fast pyrolysis kinetics and product evolution of waste pine sawdust, high heating rate thermogravimetry-Fourier transform infrared (TG-FTIR) was used to obtain the kinetic parameters and the chemical groups formed during the pyrolysis process, while pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) was used to investigate the detailed compositions of products under the staged (seven stages from 300 to 600 °C) and direct fast pyrolysis process. Spectral bands were identified for acids, alcohols, aldehydes, aromatics, esters, ethers, hydrocarbons, ketones, phenols, and sugars. Research found that the apparent activation energy for fast pyrolysis is much higher than that of slow pyrolysis. The evolution of CO2 is the major deoxygenation route. Cracking mainly occurred at the 450 °C stage with phenols, ketones, aldehydes, and sugars as the main products. The product distributions for different stages are significantly different; the selectivity of aldehydes decreased, while phenols showed an upward trend with an increase in pyrolysis temperature. Ketones and sugars reached their peak values at 450 °C. The changes in the molecular composition of each stage helped to understand the pyrolysis process. Compared with the staged pyrolysis, the direct pyrolysis process had higher selectivity of acids, aldehydes, esters, and sugars and lower selectivity of phenols, ketones, and alcohols.

Pyrolysis Kinetics of Lignocellulosic Waste Biomass (Cicer arietinum) using Iso-conversional Methods

A study on kinetic analysis of Bengal gram stalk (BGS), an agricultural waste biomass, was carried out using thermogravimetric analyser in an inert atmosphere. Thermogravimetric (TG) and Derivative thermogravimetric (DTG) curves were obtained by varying heating rates at 10°C.min−1, 20°C.min−1, 30°C.min−1, and 40°C.min−1. Three iso-conversional methods viz. Flynn- Ozawa-Wall, Kissinger-Akahira-Sunose, and Starink were applied to determine the kinetic properties and simultaneously obtained the effective activation energies for BGS pyrolysis. The average activation energy (Eα) calculated for BGS was 113.37 kJ.mol-1 for FWO; 109.47 kJ.mol-1 for KAS, and 112.36 kJ.mol-1 for Starink method, respectively. The results showed that the effective activation energies for the pyrolysis of BGS varied with the degree of conversion (α) in the range of 0.1 to 1.0. The experimental analysis revealed the correlation between activation energy and conversion factor.

Green Polyethylene in Harsh Environments: Gamma-irradiation Effects

Bio-based linear low-density polyethylene (green LLDPE) composites are used as electrical jackets/insulator for cables. Assessments of gamma-irradiation (Co-60) effects on these materials are of interest as they might be used in nuclear power plants (NPPs). Brazilian sugarcane juice-based green LLDPE composite electrical jackets were irradiated until 1000 kGy and analyzed for thermal stability and mechanical characteristics. Thermogravimetry analysis (TGA) showed increasing of pyrolysis activation energy (Ea) (under N2) from 42.7 ± 4.2 kJ/mol in unirradiated samples to 72.8 ± 4.6 kJ/mol after 60 kGy dose, as resulted of radiation-induced effects. FTIR spectra evidenced radiation-induced formation of conjugated C=C bonds after 250 kGy dose. Tensile stress and Young modulus did not change significantly until 150 kGy dose, whereas elongation at break decreased and reached 50% at 91 kGy dose. These results suggest that green LLDPE might withstand radiation damage through a NPP operating life (~ 40 years).

Catalytic upgrading of coal volatiles with Fe2O3 and hematite by TG-FTIR and Py-GC/MS

Pyrolysis plays a critical role in clean coal technology and energy conversion and is also conducive to the early peaking of carbon dioxide emissions. Light tar production from traditional coal pyrolysis using various iron-based catalysts for chemicals and fuel oil has gained attention recently. In this study, waste hematite was initially used for catalytic upgrading of rapid coal pyrolysis. Subsequently, thermogravimetric analyzer coupled with Fourier-transform infrared spectrometry (TG-FTIR) and pyrolysis gas chromatography mass spectrometry (Py-GC/MS) were utilized to compare the performances, kinetic parameters, and volatile composition of coal pyrolysis with Fe2O3 and hematite. The results showed that the maximum weight loss rate of coal pyrolysis increased by 1.55 %/min and 0.32 %/min with the addition of Fe2O3 and hematite, respectively, indicating that the pyrolysis reaction became more rapid and intense with iron-based catalysts. Both Kissinger Akahira Sunose (KAS) and Flynn-Wall-Ozawa (FWO) methods revealed that the catalysts reduced the apparent activation energy of coal pyrolysis. Online FTIR showed the emission temperature and content of coal volatiles, suggesting iron-based catalysts were conducive to the cracking of oxygen-containing functional groups and the directional cracking of groups to CO. Py-GC/MS illustrated the presence of Fe2O3 and hematite could reduce polycyclic aromatic hydrocarbons and oxygenates. In addition, a mechanism for rapid coal pyrolysis with iron-based catalysts was proposed to provide fundamental information for the transformation of aliphatic hydrocarbons, oxygenates, and polycyclic aromatic hydrocarbons. It is believed that iron-based catalysts have great potential for future research on upgrading coal volatiles and tar.

Pyrolysis of pigeon pea (Cajanus cajan) stalk: Kinetics and thermodynamic analysis of degradation stages via isoconversional and master plot methods

Detailed analysis of thermo-kinetics, reaction mechanism, and estimation of thermodynamic parameters are imperative for the design of reactor systems in thermochemical conversion processes. Present investigation was aimed at exploring the pyrolysis potential of pigeon pea stalk (PPS) by thermogravimetric experiments at 10, 20, and 30 °C/min heating rates. Maximum devolatilization of PPS was found to take place below 480 °C. The average activation energy for PPS pyrolysis was found to be 95.97, 100.74, 96.24, and 96.64 kJ/mol by Kissinger-Akahira-Sunose, Flynn-Wall-Ozawa, Starink, and Friedman method, respectively. Statistical analysis by one way analysis of variance method by employing Tukey test revealed that the difference in activation energy estimated from different methods was insignificant. Thermodynamic parameters (ΔH, ΔS, and ΔG) together with reaction mechanisms were also evaluated. Difference in the activation energy and enthalpy was found to be less than 5 kJ/mol. R2 and R3 models were found best fitted with experimental PPS pyrolysis data.

Chemical Feedstock Recovery via the Pyrolysis of Electronically Heated Tobacco Wastes

The pyrolysis of waste electronically heated tobacco (EHT), consisting of tobacco leaves (TL), a poly-lactic acid (PLA) filter, and a cellulose acetate (CA) filter, was investigated using thermogravimetric (TG) and pyrolyzer–gas chromatography/mass spectrometry (Py-GC/MS) analysis. The pyrolytic properties of waste EHT obtained after smoking were comparable to those of fresh EHT. Although the maximum decomposition temperatures (TmaxS) of waste TL and CA were similar to those of fresh EHT components, the Tmax of waste PLA was slightly higher than that of fresh PLA due to smoldering. The Tmaxs of PLA and CA were lowered when they were co-pyrolyzed with TL due to interactions between pyrolysis intermediates. The apparent activation energies for the non-isothermal pyrolysis of waste EHT components were higher than those of fresh EHT components. Py-GC/MS analysis results indicated that considerable amounts of chemical feedstocks, such as nicotine and limonene from TL, caprolactone and lactide from PLA, and acetic acid and triacetin from CA, can be recovered by simple pyrolysis of EHT. Co-pyrolysis of TL, PLA, and CA revealed that the experimental amount of lactide was much larger than the calculated value, suggesting its synergistic formation.

Investigation of kinetic and thermodynamic parameters approaches to non-isothermal pyrolysis of mustard stalk using model-free and master plots methods

Present work based on thermogravimetric analysis (TGA) to decipher in detail the pyrolysis of mustard stalk (MS) for investigating its potential for bioenergy feedstock at three heating rates (5, 10, and 20 °C/min). The thermal degradation behaviors of MS were carried out at three heating rates (5, 10, and 20 °C/min). The kinetic and thermodynamic parameters were examined using model-free isoconversional Flynn- Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS) model. The obtained activation energy for pyrolysis of MS using FWO and KAS to be 132.47 and 130.62 kJ/mol. Kissinger method was used to compute pre-exponential factor found to be in the range of 105 to 1016 s−1 at different heating rates. The average ΔH was 127.70, and 125.8 kJ/mol and ΔG is 127.74 and 127.87 kJ/mol from FWO and KAS respectively, all ΔH positive indicated endothermic nature. The Coats-Redfern approach was used to estimate the thermal degradation reaction mechanism, which revealed that the diffusion model was best suited to reflect the degradation process involving both exothermic and endothermic reactions. The analysis can help augment the experimental studies, and physicochemical characterization revealed its fuel characteristic since MS is sustainable and promising biomass for alternative processes in terms of waste management strategies.

Hydrothermal carbonization of rape straw: Effect of reaction parameters on hydrochar and migration of AAEMs

Hydrothermal carbonization (HTC) can improve biomass quality in both physical and chemical aspects for energy application. This study aims to investigate the characteristics and reactivities of rape straw (RS) hydrochars. Hydrochars were prepared at 160–240 °C with residence time of 15–120 min. Mass yield, energy yield, microstructure, functional group and migration of alkali and alkaline earth metals (AAEMs) were studied to evaluate the influence of different conditions on properties of hydrochar. The results showed that O/C and H/C ratio decreased, while the higher heating value (HHV) increased with increasing temperature and residence time. The effect of increasing temperature on hydrochar properties was more significant than residence time. The structure was changed, and hydrochar possessed a more stable form after the aromatization reaction. For the gasification reactivity of hydrochar, decomposition rate curves showed that the peak of pyrolysis and gasification moved to a higher temperature region with the increasing of HTC temperature because of the developed aromatic structures in hydrochar. The pyrolysis activation energy decreased from raw RS 71.68 to 41.03 kJ/mol in 240 °C, while gasification activation energy increased from 80.42 to 251.30 kJ/mol. Moreover, it was found that HTC can reduce the content of AAEMs efficiently and the best removal condition is 200 °C. Ca content dropped to a minimum value at 200 °C and then increased at higher temperature which may be caused by well-developed pore structure in hydrochars. This study provides basic data for comprehensive utilization of rape straw and migration mechanism of AAEMs in HTC process.

Kinetic characteristics and reactive behaviors of HSW vitrinite coal pyrolysis: A comprehensive analysis based on TG-MS experiments, kinetics models and ReaxFF MD simulations

Currently it is highly desired to study coal pyrolysis based on weight loss behavior, mathematical model of pyrolysis kinetics and advanced multi-scale molecular simulations to realize clean utilization of coal. This work presents a comprehensive analysis of HSW vitrinite coal pyrolysis based on thermogravimetric mass spectrometry (TG-MS) experiments, kinetics models and reactive force field molecular dynamics (ReaxFF MD) simulations. The weight loss and gas release behavior of HSW vitrinite coal at different heating rates was investigated by TG-MS. The kinetic parameters of coal pyrolysis were analyzed by Coats-Redfern model and distributed activation energy model (DAEM). The pyrolysis reactive behaviors and thermal decomposition process of HSW vitrinite coal was observed and analysis with ReaxFF MD simulations at atomic scale. The results show that the weight loss rate of pyrolysis decreased with increased heating rate. The trend of higher heating rate delayed the release of pyrolysis gas was consistent with TG results. The pyrolysis activation energy increases from 12.30 to 25.83 kJ/mol with further pyrolysis stage by Coats-Redfern model, and from 59.85 to 328.24 kJ/mol with higher carbon conversion hate by DAEM model. The results of ReaxFF MD simulations give complex initial chemical process of coal pyrolysis process, which agrees with the actual and expected coal pyrolysis process. Also the secondary reaction of tar in later stage of pyrolysis is observed clearly via ReaxFF MD simulations.

Roles of Small Polyetherimide Moieties on Thermal Stability and Fracture Toughness of Epoxy Blends.

Bisphenol A diglycidyl ether (DGEBA) was blended with polyetherimide (PEI) as a thermoplastic toughener for thermal stability and mechanical properties as a function of PEI contents. The thermal stability and mechanical properties were investigated using a thermogravimetric analyzer (TGA) and a universal test machine, respectively. The TGA results indicate that PEI addition enhanced the thermal stability of the epoxy resins in terms of the integral procedural decomposition temperature (IPDT) and pyrolysis activation energy (Et). The IPDT and Et values of the DGEBA/PEI blends containing 2 wt% of PEI increased by 2% and 22%, respectively, compared to those of neat DGEBA. Moreover, the critical stress intensity factor and critical strain energy release rate for the DGEBA/PEI blends containing 2 wt% of PEI increased by 83% and 194%, respectively, compared to those of neat DGEBA. These results demonstrate that PEI plays a key role in enhancing the flexural strength and fracture toughness of epoxy blends. This can be attributed to the newly formed semi-interpenetrating polymer networks (semi-IPNs) composed of the epoxy network and linear PEI.

High-Temperature Stability and Pyrolysis Kinetics and Mechanism of Bio-Based and Petro-Based Resins Using TG–FTIR/MS

Pyrolysis behavior of resins is essential for their high-temperature application. Herein, the high-temperature stability and pyrolysis kinetics and mechanism of rosin glyceride (RGE), hydrogenated rosin glyceride (HRGE), C9 petro-based resin (C9PR), and hydrogenated C9 petro-based resin (HC9PR) under a nonoxidizing atmosphere were investigated by thermogravimetry coupled with Fourier transform infrared spectrometry or mass spectrometry (TG–FTIR/MS) techniques. Friedman and Starink methods as well as reaction-order and truncated Sestak–Berggren models were used to evaluate kinetic and thermodynamic parameters, and results indicated that f(α) = (1 – α)n was the most probable pyrolysis mechanism for different resins. In addition, the average activation energies for pyrolysis of RGE, HRGE, C9PR, and HC9PR obtained by the Starink method were 188.97, 170.95, 159.69, and 151.66 kJ/mol, respectively, suggesting that bio-based resins exhibited better high-temperature stability than cycloaliphatic or aromatic petro-based resins thanks to their unique tricyclic phenanthrene structures, and the high-temperature stability of resins mildly would decrease after hydromodification due to the cracking of saturated bonds, which was well supported by TG–FTIR/MS analyses. Possible pyrolysis pathways were proposed.

Pyrolysis kinetics and product distribution of α-cellulose: Effect of potassium and calcium impregnation

Cellulose accounts for the largest proportion of lignocellulosic biomass. Herein, experimental and simulation studies are used to deeply understand the kinetic characteristics of the thermal decomposition of α-cellulose. The simulated data is in good agreement with the experimental data in the aspects of the conversion and the conversion rate versus temperature. The decomposition of α-cellulose, mainly occurring at 270–420 °C, induced an apparent activation energy ranging from 175.42 kJ/mol to 197.73 kJ/mol at a conversion of 10–90%. With 0.1–0.2 wt% K or Ca impregnation into the α-cellulose, the mean activation energy for pyrolysis was lowered (from 181.47 kJ/mol (for α-cellulose) to 141.11 kJ/mol (for 0.2 wt% K/α-cellulose) and 159.46 kJ/mol (for 0.1 wt% Ca/α-cellulose)) and higher amounts of liquid and gas products were produced. Furthermore, the addition of potassium and calcium increased the production of lower molecular weight components, such as furfural and its derivatives. The kinetic parameters of the α-cellulose pyrolysis were determined based on a nonlinear least-squares regression of the experimental data assuming first-order kinetics and correlated with the simulated result. The kinetic rate constants indicate that the predominant reaction pathway is from α-cellulose into a liquid product, rather than from α-cellulose into a gas product.

Influence of Cellulose Characteristics on Pyrolysis Suitability

Cellulose is the most abundant component of biomass and the one that requires the most activation energy (Ea) for pyrolysis. In this study, the dependence of Ea on the intrinsic cellulose characteristics, such as the degree of polymerization (DP), crystallinity, and crystal size, was studied in different cellulose samples, including samples from Eucalyptus globulus, Ulmus minor, Linun usitatissimum, Olea europaea, Robinia pseudoacacia, and Populus alba. Then, to describe the pyrolytic degradation of cellulose, the Ozawa–Flynn–Wall kinetic method was the most appropriate among the isoconversional models studied. An acceptable quadratic relationship of R2 > 0.9 between the Ea values of the different cellulose samples with their corresponding DP, crystallinity index, and crystal size values was found. Therefore, low crystallinity and low-to-medium crystal size values are desired to obtain lower Ea values for cellulose pyrolysis. On the other hand, DP did not present a clear effect on Ea in the studied DP range.

Thermogravimetric and Kinetic Analysis of High-Temperature Thermal Conversion of Pine Wood Sawdust under CO2/Ar

The gasification behavior of pine wood sawdust was investigated in CO2 with different heating rates of 5, 10, 15, and 20 °C/min from room temperature to 1400 °C by thermogravimetric analysis (TGA) and mass spectrometry (MS). It was also examined under Ar to compare the differences observed under CO2 at heating rate of 10 °C/min. Kinetics of pine wood sawdust thermal decomposition was determined by the models of FWO, KAS and master plot method. TGA results revealed different reaction sections from pyrolysis to char gasification under CO2. The pyrolysis behavior was similar under CO2 and Ar and had a similar energy required value about 590 kJ/kg from 250 °C to 420 °C. CO, CH4, and H2 were the primary gases obtained from thermal decomposition, and the amounts of which in CO2 atmosphere were higher than those obtained in Ar. The average activation energy for pyrolysis under CO2 was 184.72 kJ/mol.

A "Wastes-Treat-Wastes" Technology: Role and Potential of Spent Fluid Catalytic Cracking Catalysts Assisted Pyrolysis of Discarded Car Tires.

Spent fluid catalytic cracking catalysts (FCC catalysts) produced by the petrochemical industry are considered to be environmentally hazardous waste, and precious metals and heavy metals deposited on the surface make them difficult to treat. Even so, these catalysts retain some of their activity. The pyrolysis of waste tires is considered to be one of the most effective ways to solve the fossil fuel resource crisis, and this study attempts to catalyze the pyrolysis of waste tires using spent catalysts to increase the value of both types of waste. FCC catalysts reduced the activation energy (E) of waste tire pyrolysis. When the catalyst dosage was 30 wt.%, the E of tread rubber decreased from 238.87 kJ/mol to 181.24 kJ/mol, which was a 19.94% reduction. The E of the inner liner decreased from 288.03 kJ/mol to 209.12 kJ/mol, a 27.4% reduction. The spent catalyst was more effective in reducing the E and solid yield of the inner liner made of synthetic rubber. It should be emphasized that an appropriate increase in the heating rate can fully exert the selectivity of the catalyst. The catalyst could also be effectively used twice, and the optimum ratio of catalyst/waste tires was about 1/4.5. Compared with specially prepared catalysts, it is more cost-effective to use such wastes as a catalyst for waste tire pyrolysis.