Waste Tire Pyrolysis Research Articles

Integrated Assessment of Waste Tire Pyrolysis and Upgrading Pathways for Production of High-Value Products.

Waste tire pyrolysis has received increasing attention as a promising technology recently due to the shortage of fossil resources and the severity of environmental impact. In this study, the process of waste tire pyrolysis and upgrading to obtain high-value products was simulated by Aspen Plus. Also, based on life cycle assessment, the indexes of energy, environmental, economic, and comprehensive performance were proposed to evaluate different high-value pathways. Results demonstrate that the integrated system of waste tire pyrolysis, pyrolytic oil (TPO) refining, and pyrolytic carbon black (CBp) modification has higher energy efficiency than the independent system of TPO refining, with an improvement rate of 2.6%. Meanwhile, the resource-environmental performance of the integrated system is better. However, combined with the economic benefit, the independent system is more comprehensively beneficial, with the index of comprehensive performance (BEECR) of 0.94, which increases by 3.3% compared with the integrated system. Furthermore, the comparisons of different improved high-value paths based on the independent system as the benchmark indicate that the pathway of promoting sulfur conversion during pyrolysis to reduce the sulfur content in TPO can increase the BEECR from 0.94 to 1.064, with the growth of 13.2%. Also, the physical modification of CBp to reduce the production cost and environmental impact has better performance of BEECR, increasing by 20.2%. The final sensitivity analyses show that the combined improved high-value case established by the abovementioned two paths can achieve a favorable benefit in a wide range of crude oil and waste tire prices and the environmental tax.

Simulating vulcanization process during tire production to explore sulfur migration during pyrolysis

This paper systematically investigated sulfur transformation during pyrolysis of waste tires by simulating vulcanization process. Three formulas with rubbers, carbon black, ZnO, and typical vulcanization accelerators were prepared by vulcanization and compounded process as simulated tires. Stepwise temperature programmed pyrolysis was conducted in thermogravimetric analyzer and fixed bed reactor. Vulcanization promoted the weight loss rate for thermal degradation of vulcanized rubbers at 300–400 °C, but weakened it at 400–500 °C. The addition of vulcanization accelerators made these effects even more pronounced. Accordingly, more pyrolytic oil was obtained at 300–400 °C for vulcanized rubbers which should contribute to the partial destruction of polymer chains by vulcanization. Besides, vulcanized rubbers attained higher proportion of aromatics but less cyclenes than compounded rubbers. Vulcanized rubbers with ethyl ziram accelerator inhibited H2S release, while vulcanized rubbers with N-tert-Butyl-2-benzothiazolesulfenamide inhibited the formation of CH3SH. The detailed sulfur compounds in gas, oil, and solid char were analyzed. Vulcanization seemed to exhibit positive effect on sulfur transformation in pyrolytic products, i.e., higher retention rate in pyrolytic char but lower proportion ratio in gas. Sulfurization promoted the conversion of thiophene sulfur to inorganic sulfur and sulfides found in pyrolytic char was only ZnS.

Simulation and techno-economical analysis on the pyrolysis process of waste tire

Waste tires are more and more produced with the fast development of the auto industry and transportation and the traditional disposal method of landfill and dumping has been forbidden by many countries. It is important to choose effective disposal methods for a circular economy and sustainable development strategy. In this paper, we reviewed the different disposal ways of waste tires, analyzed their advantages and disadvantages, and thought pyrolysis is the most promising method. To evaluate the techno-economical performance of the pyrolysis process, the simulation model was built based on the pyrolysis process kinetics, and the further processing of pyrolysis oil and carbon was also considered in the simulation model. Different waste tires processing capacities were simulated and the results showed that under the low processing capacity of 20,000 ton/a, the profit of waste tire pyrolysis treatment is very low and the investment payback period is as long as about 76 years, whereas when the processing capacity reaches 50,000 tons per year, it will have a good profit and the investment payback period is shortened to 3.6 years. Further increasing the processing capacity will result in an approximately linear increase in revenue, but only a slow investment payback period.

Effect of type and volume fraction of recycled-tire steel fiber on durability and mechanical properties of concrete

Tire-bead steel wires derived from the pyrolysis of waste-tires can be converted into the discrete reinforcement for fiber-reinforced concrete (FRC). This study for the first time presents the information about selecting the optimum dosage of recycled steel-fibers (RSF) in FRC application. Therefore, two most common types of RSF i.e., plain RSF (PRSF) and twisted RSF (TRSF) were incorporated in a high strength plain concrete (PC) at seven different volume fractions i.e., 0%, 0.25%, 0.5%, 0.75%, 1%, 1.5% and 2%. Both physical and mechanical properties of FRCs were studied including density, compressive strength-f CU, modulus of rupture-f R, splitting-tensile strength-f SP, ultra-sonic pulse velocity-UPV, and water absorption-WA. The results revealed that TRSF performed better than PRSF in overall mechanical performance. Maximum compressive strength-f CU, 9-12% higher than PC, was achieved with a 0.75% volume fraction of PRSF or TRSF. TRSF was extremely useful in upgrading the f SP and fR by more than 82% and 109%, respectively, at a 1.5% volume fraction w.r.t PC. PRSF-FRC showed lower permeability than TRSF-FRC at the same volume fraction. Lower volume fractions i.e., 0.25-0.5% RSF reduced the permeability of FRC, while higher volume fractions were detrimental to WA and RCP resistance. Experimental values of mechanical (i.e., f SP and f R) and permeability properties (i.e., WA and RCP) were accurately related to predicting RSF-FRC as a function of strength class of PC and reinforcement index.

A novel low-cost material for thiophene and toluene removal: Study of the tire pyrolysis volatiles

It remains challenging to produce new and efficient adsorbents to remove sulfur compounds from waste tire pyrolysis oils. The present work investigated the ex-situ treatment by desulfurization and cracking of volatiles from the pyrolysis of waste tires using an innovative synthetic oil mixture. For this purpose, biochars from the pyrolysis of abundant biomasses (date seeds and spent coffee grounds) were used to improve the quality of these volatiles. Furthermore, the purification efficiency of these biochars was compared to that of commercial activated carbon. Thus, the influence of the operating conditions was studied. Finally, to provide an innovative insight into the desulfurization efficiency, the regeneration of the best performing desulfurization material was carried out. The results show promising desulfurization and cracking capacities of the spent coffee grounds biochar and excellent regeneration performance.

Experimental evaluation of the pyrolysis of plastic residues and waste tires

The paper presents the design of the experimental apparatus developed in order to analyse the performance of a prototype of a pyrolysis system for the exploitation of the plastic residues of industrial processes and the end-of-life tires. The small-scale pilot prototype is specifically designed for carrying out an experimental campaign aimed at determining the influence of different plastic types on the yield and on the quality of the liquid oil, gas and char obtained in the pyrolysis process. The study investigates the effect of different mixtures of various plastic products mainly made of polyethylene, styrene butadiene rubber, nylon, and natural rubber. The prototype is equipped with a control system able to monitor the main operating parameters of the process, such as the pyrogas pressure and temperature as well as the temperature inside the reactor where the pyrolysis takes place. The monitored variables are employed for deriving correlations among the operating conditions and the yield of the pyrolysis process. Moreover, SPME-GC/MS analysis were performed on different gas samples to estimate the main compounds that are contained in the syngas in comparison to the different plastic wastes analysed. Thus, the emissions of the small-scale prototype are evaluated. The results obtained by means of the experimental campaign performed on the test rig were used to carry out the economic assessment of an integrated pyrolysis system for the exploitation of the plastic residues from an industrial plant.

High-efficiency Hg(II) adsorbent: FeS loaded on a carbon black from pyrolysis of waste tires and sequential reutilization as a photocatalyst.

Iron-sulfur nano compounds have been proven to be effective in mercury removal, but the agglomeration, poor dispersion and mobility, and easy oxidation challenges limit their application. Herein, carbon black originating from pyrolysis of waste tires was used as a carrier of nano-FeS to obtain an efficient adsorbent (C@PDA-FeS). It is found that the C@PDA-FeS shows outstanding adsorption ability, excellent selectivity, and high removal rate. A maximum adsorption capacity of 1754mg/g is obtained, and the residual Hg(II) ion concentration is as low as 3.2μg/L in the simulated industrial wastewater, which meets the industrial discharge standard under the optimal conditions. Meanwhile, the removal rate of Hg(II) ion can reach 99.8% after up to 10 cycles. More importantly, the C@PDA-FeS still shows good adsorption efficiency, and the removal rate of Hg(II) ion is over 99% (25mg/L Hg(II) concentration) after 90days of storage, demonstrating the long-term stability and promising future of the adsorbent. In addition, the waste adsorbent (C@PDA-FeS/HgS) is reused as a photocatalyst to degrade methylene blue, and the corresponding degradation rate is 92.9% (10mg/L).

Production of cleaner waste tire pyrolysis oil by removal of polycyclic aromatic hydrocarbons via hydrogenation over Ni‐based catalysts

Production of cleaner waste tire pyrolysis oil by removal of polycyclic aromatic hydrocarbons via hydrogenation over Ni‐based catalysts

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

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, CO2, CO, NO, and H2O, 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.

Effects of molten salt thermal treatment on the properties improvement of waste tire pyrolytic char

Pyrolysis is a technical means for waste tires recycling, which can promote the enrichment of carbon black and facilitate the subsequent recovery. However, carbon black particles aggregated and the inorganic impurities tended to be enriched in pyrolytic char during the waste tire pyrolysis process, which is not conducive to the substitution of commercial carbon black by pyrolytic char. In the present study, a novel method using molten salts thermal treatment was proposed for the impurities removal from pyrolytic chars with different characteristics. In addition, the proper thermal treatment conditions were further estimated to obtain better performance for the physical–chemical properties improvement of pyrolytic char. Six kinds of char samples were chosen to conduct molten salts thermal treatment (MSTT) experiments at 350, 400, and 450 °C. The experimental results show that MSTT can effectively remove the impurities of different pyrolytic chars, and the most optimum reaction conditions are at 400 °C, 2 h of reaction time, and molten salt/char ratio of 10:1. In addition, after MSTT, the pyrolytic char was depolymerized, and the average particle size reduced from 36.63 μm to 19.08 μm, the specific surface area increased from 49 m2/g to 73 m2/g. At the same time, the graphite carbon content of the pyrolytic char increased from 24.41% to 70.90%, and the hydroxyl content on the pyrolytic char surface increased significantly. In summary, the physical–chemical properties of waste tire pyrolytic char were improved by MSTT, which is close to the carbon black N550 level.

Performance Improvement Effect of Asphalt Binder Using Pyrolysis Carbon Black

The generation of waste tires is rapidly increasing. Waste tire pyrolysis is an alternative to waste tire recycling. The main substances extracted in the waste tire pyrolysis method include oil, carbon black, and iron. In this study, carbon black from the pyrolysis of waste tires was used to modify and improve the permanent deformation properties of the asphalt binder, and 0%, 5%, 10%, 15%, and 20% of pyrolysis carbon black by weight were mixed in raw asphalt, which is called AP-3 and AP-5. Laboratory tests, such as the softening point test, flash point test, rotational viscometer test, dynamic shear rheometer test, and bending beam rheometer test, were carried out. The use of pyrolysis carbon black increased the softening point and rotational viscosity at 135 °C. When using 15% PCB for AP-3 and 10% PCB for AP-5, the performance improvement effect of the resistance to permanent deformation was significant. The use of pyrolysis carbon black decreased fatigue at room temperature and improved the resistance of low-temperature cracking up to −12 °C but gave poor results at −18 °C.

Decomposition of biomass gasification tar model compounds over waste tire pyrolysis char

Gasification of biomass produces a syngas containing trace amounts of viscous hydrocarbon tar, which causes serious problems in downstream pipelines, valves and processing equipment. This study focuses on the use of tire-derived pyrolysis char for tar conversion using biomass tar model compounds representative of tar. The catalytic decomposition of tar model compounds, including methylnaphthalene, furfural, phenol, and toluene, over tire char was investigated using a fixed bed reactor at a bed temperature of 700 °C and 60 min time on stream. The influence of temperature, reaction time, porous texture, and acidity of the tire char was investigated with the use of methylnaphthalene as the tar model compound. Oxygenated tar model compounds were found to have higher conversion than those containing a single or multi-aromatic ring. The reactivity of tar compounds followed the order of furfural > phenol > toluene > methylnaphthalene. The conversion of the model compounds in the presence of the tire char was much higher than tar thermal cracking. Gas production increased dramatically with the introduction of tire char. The H2 potential for the studied tar model compounds was found to be in the range of 40%–50%. The activity of tire char for naphthalene removal was compared with two commercial activated carbons possessing a very well-developed porous texture. The results suggest that the influence of Brunauer-Emmett-Teller surface area of the carbon on tar cracking is negligible compared with the mineral content in the carbon samples.Graphical abstract

Activated carbon prepared from waste tire pyrolysis carbon black via CO2/KOH activation used as supercapacitor electrode

Activated carbon prepared from waste tire pyrolysis carbon black via CO2/KOH activation used as supercapacitor electrode

Influence of CaO on the thermal kinetics and formation mechanism of high value-added products during waste tire pyrolysis

There is a lack of detailed research on the production of isoprene and D-limonene by solid base-catalysed thermal depolymerization of waste tires (WTs). This work aimed to investigate the thermal decomposition characteristics, reaction kinetics, high value-added products production and potential mechanisms during WT pyrolysis in the presence of calcium oxide (CaO) via Thermogravimetry-Fourier Transform Infrared spectrometer (TG-FTIR) and Pyrolyzer-Gas Chromatography/Mass spectrometry (Py-GC/MS). The results obtained from TG indicated that CaO accelerated depolymerization in terms of reducing the reaction temperature, which is also reflected in the kinetic parameters. It can be found that the content of D-limonene increased by 13.76% and that of isoprene increased by 37.57%, which were attributed to differences in the depolymerization mechanisms in the presence of CaO. Furthermore, CaO had a profound impact on desulfurization by reducing benzothiazole, sulfoacid, and thiophene. The potential catalytic mechanisms of isoprene and D-limonene production and desulfurization were also proposed. This work deepens the understanding of the catalytic pyrolysis of WT under CaO and unambiguously demonstrates the great potential of CaO in enhancing isoprene and D-limonene production, providing new insight for the cleaner production of high value-added products from WT.

RETRACTED: Combustion and emission behaviors of dual-fuel premixed charge compression ignition engine powered with n-pentanol and blend of diesel/waste tire oil included nanoparticles

The main aim of this study was to investigate the effect of n-pentanol percentage on the performance, combustion, and emission characteristics of a premixed charge compression ignition (PCCI) engine operated on dual-fuel mode. The primary fuel used in the engine was a blend of diesel fuel and pyrolytic oil, which was obtained from waste tires by the pyrolysis process. Moreover, CuO/ZnO (CZ) nanoparticles were added to the fuel blend to supply excessive oxygen for better combustion. In addition, n-pentanol is an ecologically innovative and cost-competitive compound used as a secondary fuel with high octane rating. For this experimental work, the fuel blend was prepared by adding 20% waste tire pyrolysis oil to 80% diesel fuel containing 50 ppm CZ nanoparticles, while n-pentanol was sprayed into the intake manifold with varying percentages, namely 10%, 20%, and 30%. As a result of the PCCI dual-fuel mode, PTO20CuZnO50P10 was found to be the best selection since it brought a significant decrement in emission parameters such as oxides of nitrogen (NOx), carbon monoxide (CO), hydrocarbon (HC), and smoke was 12%, 37%, 10%, and 23%, respectively, compared to the conventional diesel engine at peak load condition. However, it is recorded a reduction in brake thermal efficiency and an increase in specific fuel consumption under PCCI mode using PTO20CuZnO50P10 compared to the conventional diesel engine. In general, PTO20CuZnO50P10 was chosen as the best fuel for the PCCI mode of operation aiming to reduce pollutant emissions.

Kinetic Study of Waste Tire Pyrolysis Using Thermogravimetric Analysis.

The influence of particle size (0.3 and 5.0 mm) and heating rate (5, 10, and 20 °C min–1) on the kinetic parameters of pyrolysis of waste tire was studied by thermogravimetric analysis and mathematical modeling. Kinetic parameters were determined using the Friedman model, the Coats–Redfern model, and the ASTM E1641 standard based on Arrhenius linearization. In the Friedman model, the activation energy was between 40 and 117 kJ mol–1 for a particle size of 0.3 mm and between 23 and 119 kJ mol–1 for a particle size of 5.0 mm. In the Coats–Redfern model, the activation energy is in a range of 46 to 87 kJ mol–1 for a particle size of 0.3 mm and in a range of 43 to 124 kJ mol–1 for a particle size of 5.0 mm. Finally, in the ASTM E1641 standard, the activation energy calculated was between 56 and 60 kJ mol–1 for both particle sizes. This study was performed to obtain kinetic parameters from different mathematical methods, examining how the particle size and heating rate influence them.

Formation behavior of PAHs during pyrolysis of waste tires

Polycyclic aromatic hydrocarbons (PAHs) formation from the pyrolysis of waste tires is inevitable because of the complexity of tire formulations and the addition of certain chemicals. In this study, the formation behavior and distribution of PAHs in three-phases were investigated from waste tires under pyrolysis conditions. The influencing factors including the temperature, heating rate, holding time, particle size, catalyzer, and atmosphere, were systematically evaluated. The results showed that PAHs were mainly concentrated in pyrolysis oil (94.59–99.03%), followed by the gas phase (0.96–5.34%), and their content was very low in the solid phase (0.01–0.99%). A higher temperature and slower heating rate lead to partial PAHs decomposition, thus reducing their emissions. The overall formation of PAHs can be inhibited when pyrolyzing coarse-grained tire powder. Furthermore, the PAHs formation mechanisms in waste tires were determined through reaction molecular dynamics, electron paramagnetic resonance, and intermediate products. Tires were mainly decomposed into benzene series, *C2H3, and *CH3; therefore, it was determined that PAHs were formed by the joint action of the hydrogen abstraction, and vinyl radical addition and methyl addition cyclization mechanisms. Among them, low and middle-ring PAHs were formed more easily, particularly naphthalene. The generation of PAHs can be inhibited by reducing the concentration of hydrocarbons and monocyclic benzene series. Regarding the distribution law and generation pathways of PAHs, our results provide guidance for reducing PAHs formation and emissions.

Hydrogen sulfide removal from waste tyre pyrolysis gas by inorganics

The article presents research on the purification process of pyrolysis gas from hydrogen sulfide. To our best knowledge, similar studies have not been performed yet on a real pyrolysis gas obtained from waste tyres, which contains huge amounts of hydrogen sulfide - average 3.6% (up to 5.1% at 420 °C). Different sorbents were tested, among them sodium hydroxide, zinc oxide, and manganese oxide. NaOH in concentration 0.05 M appeared to be the most efficient, showing ∼94% H2S removal efficiency under the conditions studied. ZnO features a better efficiency of H2S removal from hot gas (∼55%) than MnO. Furthermore, the combination of ZnO and a 0.05 M solution of NaOH was studied. The detailed composition of the pyrolysis gas was performed, too. The main components and sulfur-containing compounds, such as methyl mercaptan, carbonyl sulfide, and ethyl mercaptan, concentrations were measured. Predominantly, the gas consists of methane, hydrogen, ethane, ethene, carbon dioxide, iso-butane, and hydrogen sulfide. Aggregated concentrations of the above-mentioned exceed 80% of the gas, which makes it a very promising gaseous fuel.

Effect of Pyrolysis Carbon Black from Waste Tire on the Mechanical Properties of SSBR/BR Blend

AbstractPyrolysis carbon black (PCB) is a main product during the pyrolysis of waste tires. Using PCB to partially replace carbon black has drawn great attention. Herein, PCB is used to replace commercial carbon black N234 in a solution‐polymerized styrene‐butadiene rubber (SSBR)/butadiene rubber (BR)/silica compound used for tire treads. The influence of liquid polyisoprene (LIR) on the SSBR/BR/silica compound is studied. The scorch time of the compound is prolonged and the curing rate increases when N234 is partially replaced by PCB, and the processing performance of the compound is improved after the addition of LIR. As N234 is partially replaced by PCB, the addition of LIR can increase the tensile strength and elongation at break of SSBR/BR/silica vulcanizates, and improve their ageing resistance. When 50% N234 is replaced by PCB in the presence of LIR, the rolling resistance and wet grip of SSBR/BR/silica vulcanizate are improved, while the abrasion resistance slightly decreased. In the presence of liquid polyisoprene, PCB can be successfully used to partially replace common carbon black in tire rubber compounds without compromising properties.

Energy, exergy, sustainability and economic analysis of waste tire pyrolysis oil blends with different nanoparticle additives in spark ignition engine

Fossil fuels are the primary source of energy for most industries worldwide. However, its resources are finite and declining day by day, and toxic gases are released due to their consumption which causes global warming and problems with the health of the living. Therefore, any alternatives to fossil fuels or any additives added to the fuel needed to be found to minimize fuel consumption and the emission of harmful gases. In this study, a spark-ignition engine fuelled with blends of petrol with different concentrations of graphite nanoparticles, Fe2O3 nanoparticles, and tire pyrolysis oil (TPO) were used to conduct energy, exergy, economic, and sustainability analyses, and the obtained results were compared with neat petrol. The blends of petrol with 40 mg/L, 80 mg/L, and 120 mg/L of graphite nanoparticles & Fe2O3 nanoparticles, as well as 5% & 10% TPO, were used in a single-cylinder, four-stroke, air-cooled SI engine in this study. The experiments were conducted on various engine loads of 2 Nm to 10 Nm with an increment of 2 Nm at a constant speed of 3500 rpm. The maximum exergy and energy efficiencies were obtained 23.05% and 21.94% at a load of 8 Nm when the testengine fired with the P120FO blend, respectively. A maximum sustainability index of 1.3 for the P120FO blend was obtained. A minimum exhaust energy rate of 0.03241 kW was obtained for P120FO. A minimum exhaust exergy rate of 0.005849 kW was obtained for P90T10. Best results in energy efficiency, exergy efficiency, sustainability index, and economic analysis were obtained for the P120FO blend compared to neat petrol. Finally, it was concluded that the addition of nanoparticles in fossil fuel increases the engine's efficiency, decreases fuel consumption, and reduces the emission of harmful gases.