Waste Tire Pyrolysis Research Articles

Microwave fast pyrolysis of waste tires: Effect of microwave power on product composition and quality

Pyrolysis of waste tires can not only solve environmental problems but also recycle waste materials. However, the poor thermal conductivity and the significant energy consumption of the conventional thermal decomposition method severely hinders the implementation of this technology. Microwave pyrolysis is an appealing approach to recycling waste tires since the waste tires contain a high amount of metal oxides additives and carbon black, which can quickly absorb microwave radiation and convert it into heat. During the pyrolysis process, the generated gaseous, liquid, and solid products were all collected separately and characterized. The major components of the pyrolysis gases were H2, CH4, and C2H4. The liquid products were complex mixtures of organic compounds with large proportions of aromatics (BTX) and limonene. The solid residues have high contents of amorphous carbon and inorganic compounds (SiO2, SO3 and ZnO) formed from additives employed in tire formulation. It is worth noting that the use of microwave pyrolysis to decompose waste tires can greatly shorten the pyrolysis time, inducing the pyrolysis reaction completed within 20 min.

Characterization of Chemically Activated Pyrolytic Carbon Black Derived from Waste Tires as a Candidate for Nanomaterial Precursor.

Pyrolysis is a feasible solution for environmental problems related to the inadequate disposal of waste tires, as it leads to the recovery of pyrolytic products such as carbon black, liquid fuels and gases. The characteristics of pyrolytic carbon black can be enhanced through chemical activation in order to produce the required properties for its application. In the search to make the waste tire pyrolysis process profitable, new applications of the pyrolytic solid products have been explored, such as for the fabrication of energy-storage devices and precursor in the synthesis of nanomaterials. In this study, waste tires powder was chemically activated using acid (H2SO4) and/or alkali (KOH) to recover pyrolytic carbon black with different characteristics. H2SO4 removed surface impurities more thoroughly, improving the carbon black’s surface area, while KOH increased its oxygen content, which improved the carbon black’s stability in water suspension. Pyrolytic carbon black was fully characterized by elemental analysis, inductively coupled plasma–optical emission spectrometry (ICP-OES), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), N2 adsorption/desorption, scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM-EDS), dynamic light scattering (DLS), and ζ potential measurement. In addition, the pyrolytic carbon black was used to explore its feasibility as a precursor for the synthesis of carbon dots; synthesized carbon dots were analyzed preliminarily by SEM and with a fluorescence microplate reader, revealing differences in their morphology and fluorescence intensity. The results presented in this study demonstrate the effect of the activating agent on pyrolytic carbon black from waste tires and provide evidence of the feasibility of using waste tires for the synthesis of nanomaterials such as carbon dots.

Characterisation of liquid oil from pyrolysis of waste tyre

The aim of this study is to characterise the liquid oil produced from pyrolysis of waste tyre. In this study, a series of experiment were carried out at various process temperature from 300 °C to 500 °C. The degradation study was carried out by using TGA, meanwhile the pyrolysis process was done using a fixed bed reactor. Liquid oil obtained from the pyrolysis was analysed using FTIR and GC-MS. The oil yield was found to decrease with increasing final pyrolysis temperature and the yield of the gas increased. The highest oil yield was 58.3 wt. %. For pyrolysis at 400 °C. The pyrolysis of waste tyre at atmospheric pressure commenced at about 340 °C and completed at 460 °C. An increase in the aromatic content of the oil was observed with increasing temperature. However, the aliphatic content decreased as the temperature increased from 300 °C to 500 °C. It was observed that the amount of aliphatic fraction in the oil decreased from 7.8 wt. % to 5.4 wt. %. In the meantime, the number of aromatic compounds increased from 37.4 wt. % to 51.2 wt. %. The main aromatic compounds were limonene, xylene, styrene, toluene, trimethylbenzene, ethylbenzene and benzene.

Tuning the product distribution during the catalytic pyrolysis of waste tires: The effect of the nature of metals and the reaction temperature

Metal catalysts based on Ni, Co, and Pd supported on SiO2 were evaluated in the catalytic pyrolysis of waste tires using pyrolysis experiments coupled to gas chromatography/mass spectrometry (Py–GC/MS) and thermogravimetric analysis coupled with Fourier Transform Infrared spectrometer (TGA–FTIR) techniques. The effect of temperature and the nature of metals on the product distribution and reaction pathways was determined. Catalytic pyrolysis promoted aromatization and cracking reactions at particularly low temperatures ca. 350 °C, leading mainly to the formation of alkenes (isoprene), aromatic terpenes (p-cymene), aliphatic terpenes (d,l-limonene), and other aromatic compounds such as benzene, toluene, and xylenes (BTX). The Pd/SiO2 catalyst was the most selective toward aromatic compounds (around 40 %), owing to its well-known hydrogenation/dehydrogenation capacity, while CC bond cleavage reactions, leading to alkenes, were more favored on the Ni/SiO2 and Co/SiO2 catalysts. In all cases, high selectivity to limonene and isoprene was observed at low temperature. Above 400 °C, no significant differences in product distribution were observed between catalyzed and uncatalyzed pyrolysis. Herein, selectivity toward high-value hydrocarbons (i.e., d,l-limonene, isoprene, BTX, and p-cymene) during the catalytic pyrolysis of waste tires was tuned by the nature of the supported transition metals (i.e., Ni, Co, Pd) and the reaction temperature (e.g., <400 °C). The results demonstrate that the use of these catalysts is a promising strategy to valorize waste tires into high added-value products.

Experimental investigation of performance and emission characteristics of a miniature gas turbine supplied by blends of kerosene and waste tyre pyrolysis oil

Fossil fuels are non-renewable sources of energy that could be depleted in the near future, giving rise to a major energy crisis. Scientists from all over the world are working on new technologies to produce fuel not only from renewable sources but also from waste. This article is concerned with: (i) waste tyre management by means of the pyrolysis process, (ii) investigation of physico-chemical parameters of waste tyre pyrolysis oil (TPO), and (iii) investigation of performance and emission characteristics of a miniature GTM-140 turbine engine supplied by blends of kerosene and waste tyre pyrolysis oil. The final aim of the research is to determine the influence of the applied blend composition (between 10 and 50% of TPO in the blends) on the performance and emission parameters of a small gas turbine. Turbine inlet and outlet temperatures, fuel flow, static thrust, thrust specific fuel consumption (TSFC) and emissions index of NOx, CO, SO2 are measured in a wide range of turbine load. The differences are the largest for the highest rotational speeds, where the temperatures, TSFC and emissions of NOx especially tend to increase with the increasing fraction of pyrolytic oil in the blends, as compared to those of kerosene. However, emissions of SO2 are lower for the all blends in the entire range of load.

Kinetic analysis of waste tire pyrolysis with metal oxide and zeolitic catalysts

Research interest in the conversion of waste tire into energy and fuels via pyrolysis process has increased extensively. To optimize pyrolysis reactor design and operating conditions, an understanding of the pyrolysis kinetics of waste tire is of fundamental importance. This study investigated the pyrolysis kinetics of waste tire in three cases (no catalyst, ZSM-5, and MnO2) under different heating rates. The thermogravimetric data showed that there was no apparent difference between the devolatilization processes of waste tire without catalyst and with ZSM-5. The activation energy was obtained by Friedman’s method, Kissinger-Akahira-Sunose (KAS) method and Flynn-Wall-Ozawa (FWO) method. The activation energy of waste tire pyrolysis suggested that MnO2 had a positive influence on the thermal decomposition of waste tire. Under the catalysis of ZSM-5, the pyrolysis of waste tire produced more C1-C4 alkanes and alkenes. While, the monocyclic aromatic compounds in the oil products were also enriched. Whereas, ZSM-5, which has been popularly used in thermal chemical conversions, had little catalytic effect on the decomposition of waste tire.

A novel approach of reapplication of carbon black recovered from waste tyre pyrolysis to rubber composites

Waste tires aggravates the two major international problems of energy supply and environmental pollution in the world. Pyrolysis can convert wasted tire to valuable fuel resources, has become attractive technology. Pyrolysis carbon black (CBp) is the main secondary product of the pyrolysis of waste tires, accounting for about 35%. The high value application of CBp is one of the bottlenecks in the waste tire pyrolysis industry. Generally, the properties of CBp/rubber composites cannot meet the requirements of tires because of its poor reinforcement and dispersion. Aim to solve this problem, a novel approach which is atomization dispersion and high temperature sputtering drying (ADSD method) is applied. To evaluate the ADSD method, the performances of CBp/rubber composites prepared by different processing methods were investigated. Experimental results revealed that the performance of CBp/rubber composites prepared by ADSD method is better than that by the traditional method in terms of vulcanization performance, physical and mechanical performance, dynamic performance, etc. The feasibility of preparing rubber composites by using CBp is also verified.

Adsorption of Lead Ions onto Chemical Activated Carbon Derived from Waste Tire Pyrolysis Char: Equilibrium and Kinetics Studies

The environmental impacts caused by the disposal of waste tires on land and impacts of metals in water is of great concern. In this study activated carbon was prepared from waste tire pyrolysis char using a chemical activation process where KOH was used as an activating agent at 600 °C in a tube furnace. The characterization techniques namely proximate analysis and X-ray fluorescence (XRF) were used. The adsorption results revealed that waste tire activated carbon (WTAC) was more effective than waste tire pyrolysis char (WTPC) on the removal of lead ions from aqueous solution. The effect of adsorption process parameters such as: adsorbent dosage and pH on adsorption of lead ions onto WTPC and WTAC were determined and optimized. A high lead ions removal efficiency was obtained at following process conditions namely: pH of 7 and adsorbent dosage of 0.25g/100ml. Adsorption isotherms studies revealed that the experimental data was best fitted with Freundlich isotherm model. The proximate analysis and XRF analysis confirmed that chemical activation of waste tire pyrolysis char took place.Keywords: Waste tire activated carbon, Adsorption, Adsorption isot

Pyrolysis of waste tire rubber: a comparative kinetic study using different models

ABSTRACT With increase in number of vehicles worldwide the amount of waste tires is also increasing. These waste tires are either discarded to a dump site or burnt in open air. In both the cases they contaminate the soil, water and air. Due to its high heating value waste tire is a good source of energy if used under controlled conditions. In this connection pyrolysis has emerged as the ultimate solution for judicious use of waste tire. However, before going through the pyrolysis process on industrial scale, understanding the kinetics of pyrolysis reaction on laboratory scale is mandatory. Therefore, in this work our focus is on the kinetics of pyrolysis of waste tire using various kinetic models. Activation energy (E) and frequency factor (A) were determined and observed to increase with fraction conversion which shows a multistep reaction. The E and A values calculated at different conversions were found in the range of 100.73–216.99 kJmol−1 and 2.5 × 109–9.0 × 1013 min−1 respectively. Based on kinetics parameters, a comparison among the different models was made. Any small variation in kinetics parameters was attributed to the selection of model chosen and the method adopted for investigation of kinetic results. The kinetic modeling will provide insights into pyrolysis reaction and the kinetic parameters determined will assist in pyrolysis of waste tire for its use as energy source on industrial scale.

Hydrotreatment of pyrolysis oil from waste tire in tetralin for production of high-quality hydrocarbon rich fuel

Pyrolysis is a green method for waste tires processing with aim to produce oil. However, the resulting oil contains a relatively large amount of sulfur and nitrogen compounds, limiting its direct use. Therefore, this study aimed to improve properties of the waste tire pyrolysis oil (TPO) particular to reduce the N and S contents. The combination of tetralin and H2 was employed to provide hydrogen source to enhance the hydrotreatment of the TPO. Effects of catalyst type (AC, Ir/C, Pt/C, Ru/C, and Pd/C), temperature (350–450 °C), catalyst loading (1–20 wt%), time (0.5–4 h), and hydrogen pressure (1 atm-9 MPa) on the upgraded products distribution and properties of the upgraded oil (UO) were examined. Positive synergetic effect between tetralin and H2 existed in favoring the reduction of gas and solid products and improving the quality of the UO. Tetralin played a very important role in transferring molecular hydrogen to activated hydrogen and favored the hydrogenation reactions. Among the noble metals examined, Pt/C presented the highest performance toward the N, O, and S removal. The lowest N (0.09 wt%) and S (15 ppm) contents of UO were obtained at 430 °C, 2 h, 3gTPO + 3gTHN, 15 wt% Pt/C, and 6 MPa H2. The UO had higher-heating values ranging from 42.42 to 44.63 MJ/kg depending on the reaction conditions. The chemical components of the UO are mainly aromatic compounds. Especially, monocyclic aromatic hydrocarbons account for about 40% of the total content.

Effect of high heating rates on products distribution and sulfur transformation during the pyrolysis of waste tires

Fast pyrolysis offers a promising efficient way for the resourceful disposal of waste tires and heating rate was a key influence factor on products properties. However, the heating rates of the widely used experimental apparatus (like thermogravimetric) were generally outside the scope of most fast pyrolysis devices. To better guide actual pyrolysis process, the present study focused on the effects of high heating rates (ranged from 60 to 6000 °C/min) on products distribution and sulfur transformation during waste tires pyrolysis. And experiments were conducted at temperatures from 425 °C to 575 °C by using a self-designed photothermal reactor. The results showed that increasing heating rates posed slight effect on the products yields at 425 °C while obviously decreased char yield by forming more gases at higher temperatures. Moreover, high heating rates promoted the fast cracking of tires to form more radical fragments, leading to the formation of numerous small-molecule H2, CH4 and H2S. Meanwhile, secondary reactions among nascent volatiles remarkably increased the fraction or aromatic compounds in the pyrolytic tar especially at 500 °C and 575 °C. Although high heating rates hardly changed the carbon distribution characteristics in the char, increasing heating rate from 60 to 600 °C/min significantly reduced sulfur content in the char, regardless of the final pyrolysis temperature. These findings were believed to well support the application of fast pyrolysis technique for the disposal of waste tires.

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

The authors would like to express their gratitude to COLCIENCIAS for the financial support to research project 1210-715-51742. F.C. acknowledges COLCIENCIAS for the PhD scholarship 757-2016. F.C. also expresses his gratitude to the Clean Combustion Research Center at the King Abdullah University of Science and Technology (KAUST) for the research internship. This research used resources of the Core Labs of KAUST.

Waste tyre pyrolysis – Impact of the process and its products on the environment

The constant development of the automotive industry causes a steady growth in the production of tyres, which have to be utilized properly after their lifespan. Pyrolysis is considered a promising solution, providing many advantages for the environment in comparison with traditional waste management methods. The pyrolysis of waste tyres was undertaken at three different temperatures (400, 500 and 600 °C) and subsequently the products obtained were investigated in the context of their influence on environmental components such as the atmosphere, hydrosphere, soil and biosphere. Special attention was focused on the sulfur-containing compounds and heavy metals. Additionally, ultimate and proximate analyses were made and the organic composition of the liquid fraction was checked. The concentration of heavy metals in pyrolysis oils and chars were, in general, very low and this allows their further usage to be considered safe for the environment and human health. Additionally, the presence of valuable chemicals such as limonene, toluene and xylene enhance the profitability of the process as well as saving natural resources. On the other hand, the high concentration of sulfur-containing compounds in pyrolytic gas and oils makes their usability dependent on desulfurisation processes. However, the very high energy content (calorific value) in all three products encourages their industrial application.

Investigation of performance and emission characteristics of an CI engine fuelled with diesel – waste tire oil – butanol blends

The present paper has focused on the impact of the n-butanol addition into the waste tire pyrolysis oil and diesel fuel (TDF). Tests were performed on a single-cylinder, and direct injection diesel engine. In the study, the engine load varied from 500 to 1250 W with an interval of 250 W. In the results, engine emission, and performance characteristics were comprehensively discussed. The paper showed that the usage of high rates of TDF in the fuel highly increased the emissions of NOx, CO, and HC. However, with the addition of high rate n-butanol in the ternary blends, it is possible to draw back the increased amounts of these emissions. On the other hand, brake specific fuel consumption (BSFC) was also decreased with the high rates of n-butanol into TDF blend, and brake thermal efficiency (BTE) was improved due to superior calorific value, density, viscosity and oxygen atoms in n-butanol as compared that those of TDF blend. NOx was higher in high rates of TDF blend; however, the addition of n-butanol ensured a drop in NOx emission, while CO was lower for neat diesel fuel at all engine load. On the other hand, HC emission was remarkably decreased with the waste tire oil and butanol addition in comparison with that of neat diesel fuel. In the conclusion, the present paper showed that the binary form of waste tire pyrolysis oil and diesel fuel blends can be used in a CI engine with no modification and the emission and performance characteristics can be improved using an alcohol additive into the waste tire oil-diesel blend.

Efficient removal of Pb (II) by inexpensive magnetic adsorbents prepared from one-pot pyrolysis of waste tyres involved magnetic nanoparticles

A novel magnetic carbonaceous adsorbent (MCA) was prepared in low cost by pyrolysis of waste tyre rubber and corn flour with incorporated magnetic nanoparticles and used as an adsorbent to remove Pb2+ in aqueous solution. The powder of waste tyre rubber, the corn flour, and the magnetic nanoparticles were heated up to 500 ℃ at a heating rate of 10 ℃·min−1 and held isothermal for 30 min. The magnetic carbonaceous adsorbent (MCA-1050) prepared showed the maximum adsorption capacity of about 66.84 mg·g−1 for Pb2+ due to the existence of the –SH, −OH, and –COOH groups on its surface. The adsorption for Pb2+ reached the equilibrium within 50 min and the adsorption kinetics fitted to quasi–second–order kinetics equation. The adsorption thermodynamic process fitted better to the Langmuir isotherm equation than the Freundlich isotherm equation, indicating a monolayer adsorption process for Pb2+. Subsequently, in order to further learn the relationship between the structures of the carbonaceous adsorbents and pyrolysis conditions, the adsorbents were analyzed by Transmission Electron microscopy, Fourier–Transform Infrared Spectroscopy, X-ray photoelectron spectrometer, and Vibrating Sample Magnetometer. Finally, the MCA-1050 loaded with Pb2+ was eluted using EDTA solution (0.06 mol·L−1, pH 8.0), which showed good reusability and over 60% of removal rate was remained after 4 cycles.

Effects of pressure and residence time on limonene production in waste tires pyrolysis process

Pyrolysis of waste tires is a promising way to cost-efficiently produce high value limonene, but the reaction characteristics and mechanisms of limonene under pressurized pyrolysis are unclear to date. This study aims to investigate the effects of residence time and pressure on limonene conversion during waste tire pyrolysis. The yields of limonene increased significantly with a decrease of residence time during high pressure pyrolysis. At a pressure of 1.0 MPa, the yield of limonene increases by 20 % as the residence time decreases from 60 s to 15 s, while limonene concentration in TDO (tire-derived-oil) increases to 35.10 wt.%. On the other hand, the pressure has a positive effect on limonene production. The yield of limonene at 1.0 MPa is approximately 1.7 times larger than that of 0.1 MPa at a residence time of 30 s. Based on Spearman correlation analysis, the mechanisms of limonene conversion at pressurized pyrolysis were studied. Longer residence time means limonene undergoes more secondary reactions to be degraded to aromatic rings such as xylene and trimethylbenzene. However, the higher N2 partial pressure during pyrolysis suppressed the decomposition of limonene, producing TDO with high limonene concentration. Therefore, methods of reducing residence time and increasing pressures promote yield and concentration of limonene in the aspect of inhibiting decomposition, which provides references for improvement in limonene production by waste tire pyrolysis.

Light olefin production using the mixture of HZSM-5/MCM-41 and γ-Al2O3 as catalysts for catalytic pyrolysis of waste tires

In this paper, micro-mesoporous HZSM-5/MCM-41 zeolites were prepared by a two-step hydrothermal method using commercial HZSM-5 with two different silica/alumina ratios (38 and 50) as starting materials. The structures, morphologies and acidity of as-prepared zeolites were analyzed using XRD, FT-IR, SEM, N2-adsorption/desorption and NH3-TPD. The HZSM-5/MCM-41 zeolites combined the acidity of microporous HZSM-5 with the pore advantages of mesoporous MCM-41. Mesopores and microspores of 3.34 and 0.95 nm in diameter were found to be present in HZSM-5/MCM-41 zeolites. When they were used to catalyze the pyrolysis of waste tires, the selectivity of light olefins for HZSM-5/MCM-41 prepared using HZSM-5 with the silica/alumina ratio of 50 as starting materials was 21.42%, higher than 18.43% of HZSM-5/MCM-41 synthesized using HZSM-5 with the silica/alumina ratio of 38. In order to further overcome the pore size constraints and mass transfer limitations of HZSM- -5/MCM-41 zeolites for catalyzing pyrolysis of waste tires, macroporous ?-Al2O3 were mixed with HZSM-5/MCM-41 and used as catalysts. The selectivity to light olefins for the mixture of ?-Al2O3 and HZSM-5/MCM-41 prepared using HZSM-5 with the silica/alumina ratio of 50 as starting materials was 33.65%, which was obviously enhanced by the introduction of ?-Al2O3.

Conversion Kinetics of the Gaseous Products of Pyrolysis of Polypropylene and Waste Tires

Numerical simulations are performed of reaction kinetics in the gaseous products of pyrolysis of polypropylene and waste tires at atmospheric pressure in the temperature range of 800 to 1300 K. The initial conditions are set by using the experimental data available in the literature. The reactions between gaseous pyrolysis products are found to result in a decrease in the mixture’s temperature of polypropylene and a temperature increase for waste tires. The increase in the initial temperature reduces the gaseous product’s conversion for both polypropylene and the waste tires. It is established that the conversion pathways for the C1–C4 alkenes and alkanes strongly depend on the initial temperature and their initial composition.

Design of effluent treatment plant for Waste Tyre Pyrolysis Industry, Siltara, Raipur

Design of effluent treatment plant for Waste Tyre Pyrolysis Industry, Siltara, Raipur

The Development of a Waste Tyre Pyrolysis Production Plant Business Model for the Gauteng Region, South Africa

Some of today’s modern life challenges include addressing the increased waste generation and energy deficiencies. Waste tyres have been identified as one of the key environmental concerns due to their non-biodegradable nature and bulk storage space demand. Pyrolysis is a thermochemical process with the potential to address the growing waste tyre problem, energy deficits, and material recovery by converting waste tyres to pyrolysis oil that can be used as a fuel. This study seeks to critically evaluate the feasibility of constructing and operating a waste tyre processing facility and then subsequently marketing and selling the pyrolysis secondary end products by developing a financial business model. The model encompasses costing, procurement, installation, commissioning, and operating a batch pyrolysis plant in Gauteng, South Africa. To achieve the study objectives, an order of magnitude costing method was used for model construction. The results showed the feasibility and sustainability of operating a 3.5 tonne per day batch waste tyre pyrolysis plant in Gauteng Province, South Africa, with a 15-year life span and a projected payback period of approximately 5 years. It was concluded that for the pyrolysis plant to be successful, further treatment steps are required to improve the process economics; also, a stable and sustainable product market should exist and be regulated in South Africa.