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A plant prototype for whole scrap tires disposal and the consequent syngas production via pyrolysis has been developed. A numerical analysis on the innovative pyrolysis reactor, constituted by an autoclave closing device and an explosion-proof water system has been carried out. The aim of this analysis is to investigate the fluid-dynamics in the py...
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... The HHV calculated from a balance for gaseous products was 34.5 MJ/kg (at 400°C), 13.0 MJ/kg (at 500°C) and 11.9 MJ/kg (at 600°C). Assuming a density of syngas as 0.95 kg/m 3 [45], the values obtained were in accordance with data provided for example by Gonzalez et al. [13] (12.6 MJ/kg), Zhang et al. [14] (18.2 MJ/kg) and Bianchi et al. [46] (42.6 MJ/kg). Moreover, the tendency indicating that syngas obtained at lower temperatures has a higher HHV than that obtained at higher temperature is similar to the observation of Laresgoiti et al. [47]. ...
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.
... Fixed-bed reactors are commonly utilised for slow pyrolysis in batch systems with oil yield ranging from 35% to 50%, while fluidised bed reactors are commonly employed in the fast pyrolysis process and require small particle sizes, with oil yields ranging from 65% to 70% [18]. A rotary kiln reactor is slightly inclined (1°-10°) to progress the waste material forward; the added advantages are that the processing speed of turning, the extent of filling, and particle dimensions can be optimised to improve product yield [19]. Stirred tank reactors are designed for processing whole tyres, resulting in a considerable energy saving on size reduction costs [20]. The vacuum pyrolysis reactor is designed to accommodate larger tyre particles at low pressure and minimum temperature [21]. ...
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.
... A test bench with a prototype innovative reactor ( Fig. 13) for the pyrolysis of whole tyres at the laboratory scale is presented in [69]. Optimisation of reactor geometry using numerical analysis of temperature and velocity fields, and simulations of the pyrolysis and the results of an experimental study are included. ...
... Reactor for the pyrolysis of whole tyres[69].W.M. Lewandowski, et al. Journal of Analytical and Applied Pyrolysis xxx (xxxx) xxx-xxx ...
This article discusses the current use of different pyrolytic reactors, their constructions and operating principles regarding the yields of main products of waste tyre pyrolytic recycling. Whether one makes a larger or smaller profit, or even a loss due to a surcharge being levied on waste tyre recycling, depends on the sale of the pyrolysis products (gas, char, oil), the proportions and market prices of which differ. The cheapest is gas, which can be used as a source of technological heat of energetically self-sufficient pyrolysis or after purification, can be burned in a boiler and converted into heat or electricity. Raw char is not expensive either. It requires upgrading and then, as carbon black, can be re-used for the production of tyres or in the form of improved carbon can be used as an absorber or catalyst. The most expensive is oil, containing mainly aromatic compounds, on the condition that it will not be burned as diesel or liquid fuel. Hence, the oil yields obtained in various types of pyrolysers are given. This review of pyrolysis reactors is organised according to the criterion of charge movement in the reactor and the means of bringing this about. Depending on the method and speed of movement of the load in reactors, they are classified as fixed-bed and movable-bed reactors. The latter group is subdivided, depending on the method of inducing this movement, into pneumatic (bubbling, spouted, circulating or transport fluidised beds), mechanical (rotary kiln, rake, auger, ablative, stirred)reactors and reactors in which the charge moves under gravity. This review focuses on the construction and operating principles of the reactors and the yields of the products of pyrolytic thermal decomposition of scrap tyres. The summary and comparison of main product yields (oil/gas/coal)obtained in different reactors and by different authors, presented in graphical and tabular form, constitute a summary and supplement to this work.
... However, the number of publications dealing with tyre pyrolysis is very low. An example might be the work of Mtui (2013) on CFD modelling of devolatilization and combustion of shredded tires and pine wood in rotary cement kilns, or the work of Bianchi et al. (2014) on CFD modelling of pyrolysis of the whole tyre focused on optimal design of the furnace and gas collector geometry. ...
A mathematical model of waste tyre pyrolysis process is developed in this work. Tyre material decomposition based on a simplified reaction mechanism leads to main product lumps: noncondensable (gas), condensable (pyrolytic oil) and solid (char). The model takes into account kinetics of heat and mass transfer in the grain of the shredded rubber material as well as surrounding gas phase. The main reaction routes were modelled as the pseudo-first order reactions with a rate constant calculated from the Arrhenius type equation using literature values of activation energy determined for main tyre constituents based on TG/DTG measurements and tuned pre-exponential parameter values obtained by fitting theoretical predictions to the experimental results obtained in our laboratory reactor. The model was implemented within the CFD software (ANSYS Fluent). The results of numerical simulation of the pyrolysis process revealed non-uniformity of sample’s porosity and temperature. The simulation predictions were in satisfactory agreement with the experimentally measured mass loss of the tyre sample during pyrolysis process investigated in a laboratory reactor.
... Temperature, C Details Heating Value, MJ/m 3 References 400 fixed bed 11.97 [19] 600 vacuum pyrolysis 17.30 [21] 450 vacuum pyrolysis 19.80 [21] 550 vacuum pyrolysis 20.50 [21] 500 vacuum pyrolysis 20.70 [21] 550 pilot plant 22.04 [61] 600 pilot plant 23.98 [61] 500 fixed bed 28.37 [19] 680 pilot plant 29.03 [61] 900 tire powder 34.90 [58] 800 tire powder 38.10 [58] 600 fixed bed 38.59 [19] 500 test bench 40.50 [69] 700 fixed bed 42.87 [19] 700 tire powder 43.20 [58] 900 fixed bed 57.50 [66] 550 fixed bed 65.60 [66] 550 pilot plant 68.70 [18] 700 fixed bed 69.50 [63] 600 fixed bed 73.80 [63] 500 fixed bed 76.70 [63] 400 fixed bed 81.60 [63] pyrolysis processes can deliver pyrolysis oil, char, calorific gases, process heat and electricity. Pyrolytic gas can be consider as a valuable energy source. ...
Scrap tires are a burdensome and common kind of waste. Almost 1.5 billion tires are produced each year and each tire produced will eventually join the waste stream. According to European Union regulations, the disposal of waste tires is prohibited; as an alternative they should be recovered and recycled. Pyrolysis allows the dissolution of the waste and it also produces useful by-products. In this process gas, liquid and solid phases are formed. Pyrolytic gases have high heating value, about 30-40 MJ/Nm³. The energy obtained from combustion of the pyrolytic gas is enough not only to perform the pyrolysis process but it can also be utilized for other applications. However, there is a big challenge: the concentration of SO2 in the flue gases is greater than regulatory limits. Similar situations could also arise with HCl, NOX and heavy metals. In order to meet regulatory requirements and maintain optimum pyrolysis, gas cleaning methods will be needed in order to remove those substances from the exhaust gases formed during waste tire pyrolysis. The main aim of this article is to review the properties of pyrolysis gas for energy recovery because it is a good gaseous fuel. In addition, possible implications will be identified.
... However, it is not likely that a solid fuel combustor without add-on particulate controls could satisfy air emission regulatory requirements in the US. Although scrap tyres can be used as a resource of fuel in cement kilns by combustion method, it is not economically wise and environmentally friendly [Undri 2014, Bianchi 2014, Quek 2013. ...
This paper deals with scrap tyre management and current exploitation routes. The disposal of tyre waste is increasing day by day at exponential rate. Exploitation of end-of-life tyres is a significant environmental issue and challenge for all countries. Rubber has long-term decay in natural conditions due to high durability for lot of climate or soil exposure and biological attacks. Scrap tyres within most countries are burned up nowadays, but this has generally negative influence. From an economic standpoint, however, the profit derived from energy recovery by tyre incineration would be offset by the expense of meeting pollution legislation. Scrap tyres can be utilized in various rubber applications. Recommended solution is to thermally reprocess tyre waste into valuable products. One of thermal processes is pyrolysis that tyre waste can be converted into crude gas, oil and solid products. For instance, solid product can be used as carbon black with quality improvements.
... The demand for bioenergy is ever growing due to the depletion of fossil fuels as well as the threats of climate change. One of the greatest challenges in today's modern society is dealing with the disposal or recycling of solid waste produced by human activity [1,2]. The issue of scrap tyres is of great importance due to the major environmental impact that they cause. ...
This article provides a review of different methods for managing waste tyres. Around 1.5 billion scrap tyres make their way into the environmental cycle each year, so there is an extreme demand to manage and mitigate the environmental impact which occurs from landfilling and burning. Numerous approaches are targeted to recycle and reuse the tyre rubber in various applications. Among them, one of the most important methods for sustainable environmental stewardship is converting tyre rubber components into bio-oil. In this study, scrap tyre management techniques including landfill, retreading, recycling, combustion, and conversion to liquid fuels was reviewed (including gasification, hydrothermal liquefaction, and pyrolysis). The effects of parameters such as reactor types, pyrolysis temperature, and catalyst on the oil, gas and solid products in pyrolysis process were investigated.
... Moreover, one of the common ways of disposal of waste tire is massive stockpiling and landfilling, but it requires a large space since tires cannot be compacted. Nevertheless, It exists the possibility of generating dangerous fire with the emission of hazardous gases [26][27][28][29][30][31]. Meanwhile, waste tires should be carefully transformed in a product with added value, and hence one of the possibilities is to convert them into carbon via pyrolysis under a controlled environment process. ...
A new acid catalyst based in a carbonaceous solid was functionalized using sulfuric acid as source of SO3H acid groups. This carbon-based material prepared by the pyrolysis of waste tire rubber was used either as catalyst or as catalytic support. The pyrolysis process was performed with a flow of N2 at relatively low temperature to obtain a mesoporous carbon and achieve an effective sulfonation. The sulfonation method of carbon obtained from tire rubber was through direct immersion into concentrated H2SO4 under reflux. The mesoporous solids were characterized by several analytic techniques including an elemental analysis derived from scanning electronic microscopy (SEM). These ones indicated the presence of polycyclic disordered carbon plates in the carbonaceous structure with a low surface area and wide pores that provided many surface acid sites. The high catalytic activity and stability of this catalyst is related to the acid site density of Bronsted acid sites and to its homogeneous distribution. The hydrophobicity presented by this material favorably prevented hydration of hydrophilic OH and SO3H functional groups. The transesterification and esterification of waste oil under sub-critical methanol mainly in the presence of sulfonated char were achieved. Hence, it was required shorter times, low temperature and significantly, a low amount of methanol compared to other studies. © 2016 American Institute of Chemical Engineers Environ Prog, 2016
... On the other hand, liquid and gas yields increased with temperature up to 38.5 and 17.8 wt% at 700°C, respectively. In order to save grinding costs, Bianchi et al. [34] are designing autoclaves for processing whole tires. ...
... High molecular weight compounds can be generated in low pyrolysis temperatures and longer residence times. New technological breakthroughs are necessary for the commercialization of low temperature pyrolysis (Bianchi et al., 2014;Díez et al., 2005;Martínez et al., 2013a). ...
Boosting of eco-innovative solutions for End of Life Tyres (ELTs) management, under the principles of the EU Resource Efficiency Roadmap and the Waste Framework Directive, can not only diminish the environmental hazards and the consequent societal cost, but also result to the establishment of a novel perception regarding ELTs; thus, a valuable stock of resources that can be exploited. Despite the extensive scientific research of the previous years on ELTs depolymerisation via pyrolysis highlighting its eco-innovative characteristics, the use of pyrolysis to process scrap tyres has not yet achieved a broad commercial success, with economic viability and product standardization to constitute the primary impediments. More specifically, pyrolysis was not applied to an extensive industrial scale so far, due to deficient market analysis, legislative barriers, economic instability and sometimes public acceptance. All the above issues are addressed by the present study. Modifications on current EU legislation can prevent or reduce delays or derailment of efforts on pyrolysis, through its differentiation from incineration. The attainment of economic viability could be realized through the valorization of the pyrolytic char towards activated carbon production for environmental depollution applications; needless to say, the penetration on niche and well-organised markets is more than essential.
