Pressures from environmental agencies contribute to the challenges associated with the disposal of waste tyres, particularly in South Africa. Recycling of waste tyres in South Africa is in its infancy resulting in the historically undocumented and uncontrolled existence of waste tyre stockpiles across the country. The remote and distant locations of such stockpiles typically complicate the logistics associated with the collection, transport and storage of waste tyres prior to entering the recycling process. In order to optimize the logistics associated with the collection of waste tyres from stockpiles, useful information about such stockpiles would include estimates of the types of tyres as well as the quantity of specific tyre types found in particular stockpiles. This research proposes the use of computer vision for categorizing individual tyres and estimating the number of visible tyres in tyre stockpile images to support the logistics in tyre recycling efforts. The study begins with a broad review of image processing and computer vision algorithms for categorization and counting objects in images. The bag of visual words (BoVW) model for categorization is tested on two small data sets of tread tyre images using a random sub-sampling holdout method. The categorization results are evaluated using performance metrics for multiclass classifiers, namely the average accuracy, precision, and recall. The results indicated that corner-based local feature detectors combined with speeded up robust features (SURF) descriptors in a BoVW model provide moderately accurate categorization of tyres based on tread images. Two feature extraction methods for extracting features for use in training neural networks (NNs) for tyre count estimations in tyre stockpiles are proposed. The two feature extraction methods are used to describe images in terms of feature vectors that can be used as input for NNs. The first feature extraction method uses the BoVW model with histograms of oriented gradients (HOG) features collected from overlapping sub-images to create a visual vocabulary and describe the images in terms of their visual word occurrence histogram. The second feature extraction method uses the image gradient magnitude, gradient orientation, and edge orientations of edges detected using the Canny edge detector. A concatenated histogram is constructed from individual histograms of gradient orientations and gradient magnitude. The histograms are then used to train NNs using backpropogation to approximate functions from the feature vectors describing the images to scalar count estimations. The accuracy of visible object count predictions are evaluated using NN evaluation techniques to determine the accuracy of predictions and the generalization ability of the fit model. The count estimation experiments using the two feature extraction methods for input to NNs showed that fairly accurate count estimations can be obtained and that the fit model could generalize fairly well to unseen images.

The amount of waste tyres being dumped is fast becoming a problem. These stockpiles take up valuable land and are an environmental and health problem. While incineration is the simplest way to recycle the used tyres it isn’t an efficient way to dispose of tyres. This research looks at developing a method for characterizing the New Reclamation Group (NRG) reclaim with the main focus on Hi-Res™ thermogravimetric analysis. Good quantification was possible using this technique. A trade off was established between resolution, sensitivity and time. While increasing the resolution allowed greater separation to be achieved the time for each experiment increased rapidly. Although kinetic models do exist for quantifying rubber components in vulcanized sample, they were not suitable for this study. When devulcanization causes significant molecular changes, such as with NRG reclaim, the decomposition profiles no longer match those of virgin materials. Formulations developed focused on mixing, rheometry, crosslink density and tensile properties. The NRG reclaim acted as a processing aid which lowered the maximum torque. This provides mixing safety as the temperature is decreased as a result of the lower torque. This effect was not seen with conventional reclaim. Rheometry tests indicated that the addition of the devulcanizates decreased the extent of cure. It was demonstrated that this could be linked to crosslink density. Testing of the 100%, 200%, 300% moduli correlated the crosslink density to the maximum torque. Although the addition of NRG reclaim reduced the tensile strength of the formulation, a link between crosslink density and ultimate tensile strength (UTS) couldn’t be made. The decrease in the UTS and increase in extension at break is possibly caused by an increase in low molecular weight material present in the formulations and decrease in crosslink density. This could possibly increase the mobility of polymer chains which could increases flexibility.

A thesis submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. Johannesburg 10th of October 2016 / Thermal pyrolysis is one of the viable technologies suitable for the management of organic solid waste, which has become a global challenge over the years. This is due to the non-biodegradability of these materials and their continuous usage across all segments of man’s daily activities. Effectiveness of the method is in converting these materials under controlled process conditions, that enable the optimization of the fraction of interest, such as the liquid fraction also referred to as pyrolytic oil with a near zero pollution effect on the environment. The main setback in the production of the liquid fraction include low yield, presence of sulphur and other aromatic compounds which have been linked to environmental pollution and health complications. This study focuses on improving the liquid fraction yield and composition obtainable from pyrolysis process. Latex natural rubber (obtained from Hevea Brasiliensis) was pyrolysed and its products compared with that of the used tyres. The production of pyrolytic oil from used tyres and natural rubber was performed using thermal and catalytic pyrolysis processes. The operating temperature range of 375 to 750 oC (at an interval of 75 oC) at a heating rate of 15oC/min and feed material particle sizes of 2, 4, 6, 8 and 10 mm were used. In addition, Zeolite NaY was synthesized from Lawani Benin River Kaolin (LBK) at a synthesis time and temperature of 9 h and 100 oC respectively, using hydrothermal synthesis method, and used for catalytic pyrolysis. The chemical characterisation revealed pyrolytic oil composition to be a complex mixture of aliphatic, aromatics, polycyclic aromatic hydrocarbons and other oxygen, nitrogen, sulphur and chlorinated compounds in small proportions. The non-catalysed and catalysed pyrolysis using natural rubber resulted in pyrolytic oil with 80 and 66% of aliphatic, 12 and 15% aromatic (with polycyclic aromatic hydrocarbons concentration of 2 and 1%). The non-catalysed and catalysed pyrolysis using used tyres yielded pyrolytic oil with 42 and 32% of aliphatic, 34 and 39% aromatic (with polycyclic aromatic hydrocarbons concentrations of 18 and 23%). The kinetics of the thermal degradation with the aid of a thermogravimetry and differential thermogravimetry analyzer was performed over a temperature range of 30 to 800 oC at a heating rate of 15, 20 and 30oC/min. Results showed that natural rubber displayed higher activation energy than used tyres, with respect to the heating rates. This is an indication that natural rubber is more difficult to thermally decompose than used tyres. The distillation temperature of the distillates was within the temperature range of the conventional petrol and diesel. The composition of the distillates revealed carbon chain length of C5-C30 with majority being C8 – C10. A spark ignition generator engine was used to perform the combustion tests for the various pyrolytic oil distillates and petrol blended in the ratio 0, 5, 10, 15 and 20% successfully without engine modification. For the fuel consumption with respect to generator run time, it was observed that an optimum of 20% natural rubber pyrolytic oil distillates (NRPD)-Petrol blend gave comparative fuel consumption behavior with that of commercial petrol. Furthermore, the 20% NRPD distillates gave optimum fuel consumption and power. Hence, a significant yield improvement and combustion performance were observed for the pyrolytic oil derived from natural rubber than that of used tyres. Further treatment of the pyrolytic oil distillates could pave the way for effective use of the oil as chemical feedstock for industries, or as substitutes for fossil fuel. It was also requisite to develop a mathematical model which adopts thermogravimetry analyser (TGA) as a dynamic apparatus to predict weight change of a material as it degrades with time at a fixed temperature. The proposed models were in three consecutive phases which were classified into three time zones 0 ≤ t ≤ t1, t1 ≤ t ≤ t2 and t ≤ t2. The general model equation for the first phase of degradation was 2 0 1 2 0 ( ) t T w t w e   , while the second phase model was and at the third phase, it is assumed that the limit of weight loss (in the second phase equation) as t tends to ∞ gives a value k , at which change in weight loss with time is negligible. The proposed model was used to plot graph of weight loss versus time at different fixed temperature which fitted well with the experimental TGA and had a characteristic pattern fitted closely to the second phase degradation of the fixed bed reactor. / MT2017

Made available in DSpace on 2014-06-11T19:26:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-01-18Bitstream added on 2014-06-13T20:15:02Z : No. of bitstreams: 1 almeidajunior_af_me_bauru.pdf: 1069638 bytes, checksum: 39c404074c23e6656f61d9ae6f57a80a (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Diante do crescimento populacional considerável e consequentemente uma maior demanda por produtos industrializados, com ciclos de vida cada vez menores, é de fundamental importância buscar alternativas que minimizem as agressões e as degradações ao meio ambiente. Neste contexto, é importante apontar os pneus inservíveis, pois se abandonados ou dispostos inadequadamente, além de se tornarem um passive ambiental, causam sérios problemas ao meio ambiente, à paisagem urbana e à saude da população. Assim este trabalho faz uma análise comparativa utilizando dados laboratoriais referentes às características do asfalto borracha (em três composições de asfalto com 15%, 18% e 20% de borracha triturada), comparando-as com as do asfalto modificado convencional, utilizado no Brasil na atualidade (asfalto modificado com polímeros SBS) que atende a especificação atual do DNIT 129/2010. As características e os comportamentos foram avaliados com os ensaios de penetração, ponto de amolecimento e fulgor, viscosidade, recuperação elástica e separação de fases. Através dos ensaios, conclui-se que os dois matérias possuem características distintas, como por exemplo, no que diz respeito à penetração e ao ponto de amolecimento, com comportamento inversamente propocional, quanto maior o ponto de amolecimento menor a penetração, quanto à viscosidade essa conclusão também pode ser aplicada, isto é, quanto maior o teor de borracha maior a consistência, nos ensaios de separaçãode fases, nota-se que quanto maior o teor da borracha maior é a separação, já nos ensaios de recuperação elástica os valores foram próximo dos 50% / Given the considerable population growth and consequently a greater demand for industrial products, with the cycles ever smaller, it is very important to seek alternatives that minimeze the aggression and the degradation of the environment. In this context it is important to point out the tire, it is abandoned or disposed of improperly, and become an environmental liabitity, cause serious problems for the environment, landscape and people's health. So this paper makes a comparative analysis using laboratory data regarding the characteristics of the asphalt rubber (three asphalt compositions with 15%, 18% and 20% crumb rubber), comparing them with those of conventional modified asphalt, used in Brazil today (SBS polymer modified asphalt) that meets the current specification of DNIT 129/2010. The characteristics and performance were evaluated according to the tests of penetration, softening point and flash, viscosity, elastic recoveru and separation of phases. Through trials, it was conclused that the two materials have distinct characteristics, such as with regard to penetration and the softening point, to conduct inversely, the softening point of less penetration, such as the viscosity conclusion can also be applied, ie the higher the rubber content greater consistency in testing phase separation, it is noted that rubber content the greater the separation already during the testing of elastic recovery values were around 50%

Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2017. / Energy security, environmental and economic issues have spurred the interest in pyrolysis of scrap tyres for the production of fuels and energy in South Africa. However, the application of the process on a commercial scale is being hampered by the high cost required to upgrade the comparatively low quality pyrolytic products as well as the high energy input. Further insights into the mechanisms of thermal degradation of rubber will assist to improve on the process economics for production of liquid hydrocarbons fractions suitable for use as transportation fuels and chemicals. This study developed a correlation to predict the contents of waste tyres that will be converted into hydrocarbons during pyrolysis from the proximate analysis data. The mechanism/kinetics of thermal degradation behaviour of waste tyres is also studied, in order to locate the optimal temperature that will maximize the yield of liquid hydrocarbons and other recoverable materials. Data from thermogravimetric analysis is used to determine the kinetic constants for the pyrolysis reaction over a temperature range of 500 °C - 750 °C. A relationship between the optimal temperatures and the volatile mater content depending on the desired products was obtained. This is necessary to eliminate thermal cracking of the pyrolytic oil into the non-condensable gas that will result from excessive temperature and the associated energy cost. Relationship to determine the kinetic equation constants is presented as a function of the volatile matter content. An inductor furnace batch reactor system is used to carried out the pyrolysis reaction, using Argon as the inert gas to provide the oxygen free environment required. The products are sent through a 2-stage condensers, the first operated at room temperature to collect the pyrolytic oil, and the second maintained at -5 oC to collect the condensable pyrolytic gases.

Orientador: Rosane Aparecida Gomes Battistelle / Banca: Anderson Manzoli / Banca: Barbara Stolte Bezerra / Resumo: Diante do crescimento populacional considerável e consequentemente uma maior demanda por produtos industrializados, com ciclos de vida cada vez menores, é de fundamental importância buscar alternativas que minimizem as agressões e as degradações ao meio ambiente. Neste contexto, é importante apontar os pneus inservíveis, pois se abandonados ou dispostos inadequadamente, além de se tornarem um passive ambiental, causam sérios problemas ao meio ambiente, à paisagem urbana e à saude da população. Assim este trabalho faz uma análise comparativa utilizando dados laboratoriais referentes às características do asfalto borracha (em três composições de asfalto com 15%, 18% e 20% de borracha triturada), comparando-as com as do asfalto modificado convencional, utilizado no Brasil na atualidade (asfalto modificado com polímeros SBS) que atende a especificação atual do DNIT 129/2010. As características e os comportamentos foram avaliados com os ensaios de penetração, ponto de amolecimento e fulgor, viscosidade, recuperação elástica e separação de fases. Através dos ensaios, conclui-se que os dois matérias possuem características distintas, como por exemplo, no que diz respeito à penetração e ao ponto de amolecimento, com comportamento inversamente propocional, quanto maior o ponto de amolecimento menor a penetração, quanto à viscosidade essa conclusão também pode ser aplicada, isto é, quanto maior o teor de borracha maior a consistência, nos ensaios de separaçãode fases, nota-se que quanto maior o teor da borracha maior é a separação, já nos ensaios de recuperação elástica os valores foram próximo dos 50% / Abstract: Given the considerable population growth and consequently a greater demand for industrial products, with the cycles ever smaller, it is very important to seek alternatives that minimeze the aggression and the degradation of the environment. In this context it is important to point out the tire, it is abandoned or disposed of improperly, and become an environmental liabitity, cause serious problems for the environment, landscape and people's health. So this paper makes a comparative analysis using laboratory data regarding the characteristics of the asphalt rubber (three asphalt compositions with 15%, 18% and 20% crumb rubber), comparing them with those of conventional modified asphalt, used in Brazil today (SBS polymer modified asphalt) that meets the current specification of DNIT 129/2010. The characteristics and performance were evaluated according to the tests of penetration, softening point and flash, viscosity, elastic recoveru and separation of phases. Through trials, it was conclused that the two materials have distinct characteristics, such as with regard to penetration and the softening point, to conduct inversely, the softening point of less penetration, such as the viscosity conclusion can also be applied, ie the higher the rubber content greater consistency in testing phase separation, it is noted that rubber content the greater the separation already during the testing of elastic recovery values were around 50% / Mestre

This study was conducted at the Virginia Tech Power Plant to measure and compare stack emissions while firing coal alone and coal mixed with shredded tires. The coal-tire mixtures consisted of 10 and 20 percent tire chips. Modified EPA method 5 sampling train was used to determine particulate emissions. CO emissions were determined with an ENERAC 2000 gas analyzer. Supelco XAD-2 resin was used in the modified method 5 sampling train to adsorb nonpolar, vapor phase hydrocarbons. The XAD-2 resin was extracted and the wash concentrated before High Performance Liquid Chromatography (HPLC) was used to quantify the presence of benzene, chrysene, phenol, and benzo(a)pyrene. Particulate emissions resulting from the combustion of 0, 10 and 20 percent tire mixtures with coal were 0.88, 2.32, and 2.13 lb/10⁶ Btu, respectively. For carbon monoxide, the emissions were 0.17,0.22, and 0.33 1b/10⁶ BTU for 0, 10, and 20 percent tire mixtures, respectively. Large variations in polynuclear aromatic hydrocarbon (PAH) emissions were observed. Therefore, only trends in the PAH data can be discussed. Phenol emissions appeared to increase with the addition of shredded tires to the combustion process. Benzene and benzo(a)pyrene emissions appeared to decrease with the addition of shredded tires to the combustion process. An increase in chrysene emissions for 20% addition of shredded tires was observed. A larger data base is needed in order to develop stronger conclusions regarding PAH emissions resulting from coal/tire shred combustion in a conventional spreader stroker. / Master of Science

Thesis (MBA)--Stellenbosch University, 2012. / Tyre waste from end-of-life tyres (ELTs), sometimes erroneously defined as a type of waste, in fact represents a renewable energy resource that is highly competitive as replacement fuel to coal in the form of tyre-derived fuel (TDF) or useable as rubber crumb in other products. In this research study, the main utilisation options considered were based on rubber crumbing through ambient and cryogenic processing. Pyrolysis, the so-called ‘holy grail’ of tyre technologies, rubberised asphalt products, TDF options and various other product options from tyre crumb as basis were considered. Although pyrolysis technology is highly commendable and environmentally friendly, it is still a process with too many variants and presents an unstable economic model that is not attractive to entrepreneurs. Rubberised asphalt depends on policy decisions from local and national authorities supporting initial higher spending and allowances on budgets to acquire future savings from the longevity in the product. The policy requirements and the instability that politically-inspired decisions carry with them are contributing to the unattractiveness of this solution to the entrepreneurial fraternity. Through government requiring a certain percentage of asphalt pavements to contain rubber (like in the United States of America (USA)), rubberised asphalt could be a very useful and viable option to produce. In the USA, the Environmental Protection Agency (EPA) recently avoided the return to coal in industrial kilns currently using TDF based on its beneficial carbon dioxide (CO2) emission and cost structures by defining TDF as Reasonably Available Control Technology (RACT) to existing coal-burning industrial kilns. In South Africa, the usage of TDF should be of interest to Eskom and the cement industry. TDF (produced from end-of-life tyres), defined as a renewable energy resource due to its proven biomass component and with its high calorific value, presents higher energy output values in comparison to coal and furthermore presents the industry with lower input costs per ton and reduces the CO2 emission factor. Entrepreneurial intervention involving Eskom and/or the cement industry in South Africa with the utilisation of end-of-life tyres as renewable energy resource is an overdue business opportunity. With more than ten million tyres per year available in South Africa and a stockpile of more than fifty million waste tyres, sustainability of TDF supplies is a reality. TDF is much cheaper per ton than coal and emits approximately 20 percent less CO2 and/or CO2e than low-grade coal to produce the same electricity output. From all the information gathered, it is clear that in countries where coal energy is extensively used, TDF utilisation not only reduces the tyre waste issues, but it also serves as an environmentally-friendly renewable energy resource in electricity production and cement kilns; the industry with some of the highest CO2 emission risks. The final chapter of this report presents a schedule representing the choice of tyre processing and disposal methods ranked by environmental preference and defining the priorities linked to process and product choice.

[pt] Há mais de um século a humanidade usufrui de um invento essencial ao desempenho, economia e conforto à rodagem de veículos: o pneu. Entretanto, o pneu tem uma vida útil limitada, caracterizada pela redução de suas ranhuras - até o limite que comprometa a estabilidade do veículo. Uma vez ultrapassada a vida útil, sobra uma carcaça, constituída por materiais de alta resistência e toxicidade, que vem sendo, simplesmente, descartada e lançada à natureza. Em conseqüência, o pneu é considerado hoje um dos maiores problemas ambientais do mundo. Além de demorar até 600 anos para se decompor, um pneu pode causar diversos malefícios para a sociedade e o meio ambiente, quando dispostos inadequadamente. É nesse contexto que a logística reversa pós-consumo vem se desenvolvendo, ou seja, estudando maneiras de como um produto descartado pela sociedade pode retornar ao ciclo de negócios. Este trabalho apresenta um estudo do problema logístico reverso na reciclagem industrial por pirólise com xisto de pneus. O objeto de estudo será o programa Paraná Rodando Limpo, um projeto desenvolvido no estado do Paraná, que coleta e recicla pneus descartados. Além de descrever os agentes envolvidos, traçar e caracterizar a rede reversa desde a captação, transporte e reciclagem dos pneus, um estudo de otimização de rotas foi proposto para tornar o processo mais eficiente. / [en] For more than a century, the world civilization has benefited from an invention to essential the performance, cost reduction, and comfort of vehicles: the tire. However, the tire has a limited useful life, characterized by the reduction of its grooves, up to a limit that jeopardizes the stability of the vehicle. Once such useful life is exceeded, a carcass constituted by high- resistance and toxicity materials is discharged and thrown away in the environment. As a consequence, today the tire is considered one of the largest environmental problems in the world. It takes more than 600 years for a tire to decompose, resulting, when not properly disposed, in several problems to the society and its environment. In this context the post-consumption reverse logistics is being developed, namely, studying ways for a product that has been discarded by the society returning to the business cycle. This work presents a study of a reverse logistics problem in the industrial recycling of tires by pyrolysis with shale. The object of study will be the Parana Rodando Limpo project (Parana running in a clean way) developed by the State of Parana, which is in charge of collecting and recycling tires that are discharged. The study describes all the involved agents, outlines and characterizes the reverse logistics flows including the collection, the transport and the recycling of the tires and, in addition, proposes a routing optimization study in order to improve the efficiency of the process.

Orientador: Luísa Andréia Gachet Barbosa / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Tecnologia / Made available in DSpace on 2018-08-26T12:45:29Z (GMT). No. of bitstreams: 1 Silva_FabianaMariada_M.pdf: 2221147 bytes, checksum: acb168d3d261f81f3d6f6d1d25e50816 (MD5) Previous issue date: 2014 / Resumo: O reaproveitamento de resíduos na construção civil tem sido uma alternativa viável para diminuir o consumo de materiais naturais e a disposição inadequada dos resíduos no meio ambiente. Neste trabalho avaliou-se o reaproveitamento de resíduo de borracha de pneus, proveniente do processo de recauchutagem, em substituição parcial do agregado miúdo natural, para a produção de pisos táteis intertravados de concreto. O piso tátil de concreto é uma peça utilizada na pavimentação, que permite a percepção do ambiente ou rotas acessíveis, proporcionando mais segurança e autonomia para as pessoas com deficiência visual. A substituição foi feita em relação à massa da areia nas proporções de 10%, 20%, 30%, 40% e 50%. As seguintes propriedades do concreto foram investigadas: consistência no estado fresco, resistência à compressão, resistência à tração na flexão, absorção de água, índice de vazios, massa específica do concreto endurecido, resistência à abrasão, resistência ao impacto e análise de microestrutura. Embora a grande limitação do uso da borracha de pneus como agregado no concreto seja a redução das resistências mecânicas, os traços com até 50% de substituição atingiram ótimos valores de resistência à compressão e resistência à tração na flexão e apresentaram melhores resultados de resistência à abrasão. A utilização do resíduo de borracha de pneus, em substituição parcial da areia natural no concreto para a produção de piso tátil, além de contribuir com a sustentabilidade na construção civil, por meio da economia de extração de matérias-primas e redução do descarte e acúmulo inadequado de pneus inservíveis, proporcionou melhorias a algumas propriedades importantes para a eficiência e qualidade do piso tátil de concreto / Abstract: The reuse of waste in construction has been a viable alternative to reduce the consumption of natural materials and the improper disposal of waste on the environment. In this work recycled tire rubber (crumb rubber) was used as aggregate in concrete to produce tactile paving block. The concrete tactile paving block allows perception of the place or accessible routes, providing more security and independence for people with visual disabilities. The crumb rubber was used to replace sand by mass at the level of 10%, 20%, 30%, 40% and 50%. The concrete characterization was performed by testing its consistency, compressive strength, flexural strength, water absorption, porosity, density, abrasion resistance, impact resistance and microstructure analysis. Although the major limitation using the crumb rubber as aggregate in the concrete is to reduce the mechanical strength, the mixtures with up to 50% of substitution reached optimal values ??of compressive strength and flexural strength and showed a better abrasion resistance. The use of crumb rubber in partial replacement of natural sand in concrete to produce tactile paving block, proved to be a viable alternative. Besides contributing to construction sustainability, minimizing the extraction of raw materials, and reducing improper disposal and accumulation of scrap tires, provided improvements to some important properties that assure the efficiency and quality of the concrete tactile paving block / Mestrado / Tecnologia e Inovação / Mestra em Tecnologia