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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Cirkulär ekonomiför plastavfall : Hantering av akrylplast som ett steg mot ett merhållbart samhälle / Circular economy of plasticwaste : A step towards a more sustainable society by handling acrylic plastic

Bondemark, Emma, Heinevik, Josefin January 2022 (has links)
Purpose – The aim of the study is to investigate the possibilities for circular economy in acrylicplastic in the lighting industry. To answer the purpose, it was broken down into two researchquestions: [1] What characterizes the handling of acrylic plastic waste by lighting manufacturers? [2] How can lighting manufacturers achieve a more circular handling of acrylic plastic waste? Method – To be able to answer the research questions, a case study was conducted at acompany active in the lighting industry. The data collection consisted of observations,interviews, and document studies. The observations were unmasked and of a direct nature. Theinterviews that were held were both unstructured and semi-structured. The documents wereinvoices and quotations mostly collected from the case company. Furthermore, four differentsolutions were developed with help of the theoretical framework and collected data. The empiricand the theoretical chapters were compared to be able to analyse and answer the researchquestions. Findings – The study shows that a company in the lighting industry throw away plastic lensesas they believe that they have no use for them. The lenses are made of acrylic plastic and arethrown in combustible waste. The waste goes to energy recovery that provides electricity,district heating and district cooling. During the combustion process, carbon dioxide is releasedwhich affects the environment. It is better to let the waste go to energy recovery than landfilling.To achieve a more circular handling of acrylic plastic waste, it is recommended to first andforemost reduce the waste. It is the result of one of the solution proposals "Minimize worksteps" which involves a point effort to take advantage of acrylic plastic instead of throwing itaway. In situations where there is no possibility of reducing, companies should instead try toreuse the acrylic lenses, which is a result of the solution proposal "reuse". In 2024, there willopen a new chemical recycling centre in Sweden that companies should keep track of. Implications – The study has implications for companies in the lighting industry that useacrylic plastic. It is also suitable for companies outside the lighting industry that handle acrylicplastic waste, as the study contributes to increased knowledge about circular economy and howacrylic plastic waste should be handled to benefit the circular economy. The study helps tohighlight potential approaches for environmentally friendly handling of acrylic plastic. A newrecycling centre opens 2024 in Stenungsund, which is the first in Sweden that can chemicallyrecycle acrylic plastic. It is recommended to talk to them early to review costs and opportunitiesthat arise in connection with the opening of the recycling centre. Limitations – The environmental impact of the study is measured in carbon dioxideemissions. No other environmental aspects are considered as carbon dioxide includes the areasthat are relevant, based on the size of the study. Due to the time constraint, the study wasconducted on only one case company, which may lower credibility. More companies should bestudied in order to further generalize and strengthen credibility even more.
22

Formulation de mélanges de polyoléfines à l’aide d’une extrudeuse à très haute vitesse : Application à la dispersion de particules de traceurs, détectables par fluorescence X ou UV, en vue du tri de déchets polymères post-consommation / Formulation of polyolefin blends using high shear extruder : Application of this technique to the dispersion of particles of tracers detectable by X or UV fluorescence for sorting polymers from post-consumer waste

Louizi, Molka 04 December 2013 (has links)
Cette thèse, qui s’inscrit dans le cadre du projet ANR Eco-Tech TRIPTIC, a eu comme objectif de contribuer au tri industriel en cadence de polymères contenant des traceurs détectables grâce à leurs propriétés en fluorescence X ou UV. Dans un premier temps, étant donné que le coût des traceurs choisis pour l’étude TRIPTIC est assez élevé, nous avons réalisé une étude préliminaire, avec des particules modèles de silice, visant à optimiser la dispersion de charges dans une matrice polypropylène/éthylène propylène rubber (PP/EPR). Nous avons montré que l’extrusion à taux de cisaillement élevé est une technologie efficace permettant une dispersion homogène de charges de tailles micro ou nanométriques. Dans un deuxième temps, après optimisation des conditions de dispersion, nous avons extrapolé nos résultats à la dispersion de particules de traceurs UV dans différentes matrices thermoplastiques. Nous avons montré que la dispersion de 1000 ppm de particules de traceurs, de tailles micrométriques, dans des matrices polypropylènes, en extrusion à haute vitesse (N= 800 rpm), n’a pas d’impact sur les propriétés mécaniques et physico-chimiques des mélanges tracés, ainsi que sur la photo-dégradation sous rayonnement UV. Cette fine dispersion a non seulement permis la conservation des propriétés des polymères tracés mais aussi une bonne détection dynamique, tant en fluorescence X qu’UV, sur un prototype conçu par des partenaires du projet (Pellenc Selective Technologies, CEA-LITT et ENSAM- LCPI). Enfin, nous avons validé l’extrusion à haute vitesse pour compatibiliser des mélanges de polymères ternaires (PP/EPR)/PE (polyéthylène) pouvant correspondre à la valorisation de polymères post-consommation, par exemple dans l’hypothèse où on souhaite recycler (PP/EPR) et PE ensembles. Les propriétés prometteuses des mélanges obtenus doivent leur permettre de trouver des applications dans l’industrie automobile, par exemple. Cette voie est d’un grand intérêt pour les applications industrielles, car elle permet d’envisager des propriétés mécaniques élevées pour les polymères recyclés. Elle ouvre aussi de nouvelles perspectives pour l’élaboration de matériaux allégés, obtenus à partir de matières vierges ou recyclées. / This thesis, which is part of the ANR Eco-Tech TRIPTIC project, had the objective of contributing to industrial sorting rate of polymers containing tracers detectable by their fluorescence X or UV properties. At first, given that the cost of tracers selected for TRIPTIC study is quite high, a preliminary study is conducted with models of silica particles to optimize the dispersion of fillers in polypropylene / ethylene-propylene rubber (PP / EPR) matrix. It was found that processing under high shear rate is an effective technology for accomplishing a homogeneous dispersion of micro or nanoscale fillers. In a second step, after optimization of dispersion conditions, our results are extrapolated to the dispersion of UV tracer in different thermoplastic matrices. It was shown that the dispersion of 1000 ppm of micrometer tracer particles, in polypropylene matrices, extruded at high shear rates (N = 800 rpm), has no impact on the mechanical and physico-chemical properties as well as in the photo-degradation of the polymer after UV irradiation exposure. This fine dispersion was beneficial not only for the conservation of the properties of traced polymers but also for achieving a good dynamic detection of UV or X tracers using a prototype developed by the project partners ( Pellenc Selective Technologies , CEA- LITT and ENSAM - RPI ). Finally, high shear processing has successfully used to the compatibilization of ternary blends ( PP / EPR ) / PE (polyethylene) which may correspond to the post-consumer polymers. This technique has proved to be an effective method to produce polymer blends with unique mechanical properties. This novel strategy of compatibilization is of a particular interest, especially for industrial application prospects. It also opens new perspectives for materials lightening as well as “high shear recycling” of immiscible polymers.
23

Potential of chemical recyclingto improve the recycling of plastic waste / Potential för kemisk återvinningför att förbättra återvinningen av plastavfall

Solis, Martyna January 2018 (has links)
Chemical recycling can improve the plastic recycling rates and reduce the level of CO2 from fossil plasticsproduction. Thus, it is seen as an attractive technology in the action towards meeting the emission, circulareconomy and recycling targets. In the Swedish context, it could help reach the carbon neutrality goal by2045. This thesis aims to investigate the potential of chemical recycling in the Swedish plastic recyclingsystem with Brista waste-to-energy plant in Stockholm as a case study. The thesis describes different stagesof current Swedish plastic recycling system and quantifies material losses at every stage. The recycling rateof plastic packaging in the household waste stream in Stockholm was found to be lower than 7%.Remaining 93% is sent for energy recovery through incineration. The feasibility of implementing differentchemical recycling technologies is analysed together with the Technology Readiness Level (TRL). Theresults showed that there are three technologies with the highest TRL of 9: thermal cracking (pyrolysis),catalytic cracking and conventional gasification. The important parameters when implementing chemicalrecycling in an existing facility are discussed and used for the feasibility analysis of implementing thesethree technologies in Brista facility. It is not obvious which technology is the best one for this application.Gasification is proven for the production of intermediates (oil or syngas) which can be used for newplastic production, however, the scale of Brista facility is not large enough for a gasification plant to befeasible. Pyrolysis and catalytic cracking could be used at a smaller scale, but they have not contributed tothe production of new plastics so far, thus, both technologies would require further research and tests ona pilot scale before moving to commercial operation. The findings from this study have to be followed byan in-depth analysis of real data, from pilot or commercial projects, which is currently unavailable.The major challenges to implement chemical recycling of waste plastics in Sweden are of economic andpolitical nature. The key point in successful deployment of chemical recycling is the development ofa business model which would ensure that all actors along the plastic recycling chain benefit economicallyfrom the solution. For the Brista 2 plant case, the challenges include Stockholm Exergi’s insufficientexpertise to perform chemical recycling independently, uncertain feedstock purity requirements andchallenging market situation. / Kemisk återvinning har potentialen att öka återvinningsgraden av plastförpackningar och minska därmedminska klimatpåverkan från fossila plastprodukter. Således ses den som en möjlig teknik för att mötautsläpps- och återvinningsmål samt införandet av en cirkulär ekonomi. I ett svenskt sammanhang kan detbidra till att nå målet om netto noll utsläpp 2045. Denna uppsats syftar till att undersöka potentialen förkemisk återvinning i det svenska återvinningssystemet för plast, med det avfallseldade Bristaverket somfallstudie. Avhandlingen beskriver ingående led i den nuvarande svenska plaståtervinningssystem ochkvantifierar materialförluster i alla steg. Återvinningsgraden för plastförpackningar i hushållsavfalleti Stockholm visar sig vara lägre än 7%. Återstående 93% skickas för energiåtervinning genom förbränning.Analysen av olika teknologier för kemisk återvinnings genomförs med hjälp av Technology ReadinessLevel (TRL). Resultatet visar att det fanns tre teknologier med högsta TRL på 9: termisk krackning(pyrolys), katalytisk krackning och konventionell förgasning. Viktiga parametrar för kemisk återvinningkopplat till en befintlig anläggning diskuteras och används för genomförbarhetsanalys av de tre valdateknologierna genom en fallstudie vid Bristaanläggningen. Det är inte uppenbart vilken teknik som är denbästa för denna applikation. Förgasning är bevisat framgångsrik för produktion av intermediära produkter(olja eller syngas) som kan användas för ny plastproduktion, men Bristaanläggningens storlek är för litenför att en förgasningsanläggning ska varamotiverad. Pyrolys och katalytisk krackning kan användasi mindre applikationer, men de har hittills inte lyckats bidra till framställning av ny plast. Därför skullebåda teknikerna kräva ytterligare forskning och test på pilotskala innan de skalas upp till kommersiell drift.Resultaten från denna studie måste följas av en djupgående analys av verklig data, från pilotprojekt ellerkommersiella projekt, som för närvarande inte är tillgänglig.De stora utmaningarna för att genomföra kemisk återvinning av plastavfall i Sverige är av ekonomisk ochpolitisk karaktär. Nyckeln till framgångsrik spridning av kemisk återvinning är utvecklingen av enaffärsmodell som säkerställer att alla aktörer längs plaståtervinningskedjan kan dra ekonomiskt fördel avlösningen. För en anläggning i Brista finns utmaningar i form av Stockholm Exergis otillräckliga expertisinom området kemisk återvinning, osäkra råvarukrav och en utmanande marknadssituation.
24

Developing a closed-loop supply chain to eliminate Single Use Plastic products : Implementing Circular Economy practices driven by EU commission directives

Ottosson, Elsa, Oweini, Rania January 2023 (has links)
Single use plastic products (SUPs) are a primary cause of plastic pollution causing significant environmental harm. These products have little to no value after use and are challenging to recycle cost efficiently. In a bid to combat this issue and foster circular economy, the European Union has declared a series of directives to gradually phase out SUPs as a strategy to eliminate these disposables from the market. This approach allows the market time to discover alternative solutions to replace SUPs, promoting the adoption of reusable products. To make a sustainable system of reusable products feasible and profitable, the key lies in devising a business model designed for a circular strategy of repeated use of goods. One effective approach involves establishing a closed-loop supply chain (CLSC) which entails the entire life cycle of a product, from sourcing raw materials, through manufacturing, utilisation, collection, reverse logistics and recycling. The purpose of this study was to develop a CLSC system for reusable plastic products between a plastic producing small or medium sized enterprise (SME) and an incumbent firm customer to attain a smooth transition from linear to circular economy. Employing an inductive approach, this case study considered the EU-directives as observational data, the change of business model as the result, and a general recommendation as the rule. The research method encompassed conducted interviews, mathematical prototyping, product design, and life cycle analysis, using various tools and methods in the process. Two case companies were involved: one large incumbent firm and one plastic producing SME. The aim was to design a circular business model (CBM) to capture the value of the collaboration between these two companies. After an analysation of the current situation, the main obstacles to a successful transition were identified. A comprehensive solution was developed, including a network of partners for the CLSC, a reusable product design, and the necessary implementation calculations. The finalised business model was anchored in the principles of the CLSC, the product design specifications and the calculations that determined the system’s viability. Implementation of the CBM would yield economic advantages for both stakeholders, as well as an improved green image factor and advancement in circular economy. Furthermore, this transition would cultivate valuable and lasting business relationships for both companies. These case findings harmonise with established theories which emphasise the significance of business models that are dependent on collaboration and long-term strategic planning. Lastly, they also underscore that value is created in product utilisation and not ownership.
25

Recycling of uPVC window profile waste

Kelly, Adrian L., Coates, Philip D., Rose, R.M., Weston, S. January 2007 (has links)
No / Methods of recycling unplasticized polyvinyl chloride (uPVC) window frame waste were investigated. The quality of untreated granular waste was compared to that of waste treated by a range of contaminant removal processes including melt filtration and dissolution. Processability of each recyclate was evaluated by using a highly instrumented single screw extruder that enabled melt viscosity and process variation to be monitored in real time. Product quality measurements such as mechanical properties and surface defects were made on extruded strip, and the nature of the stabilizers present was determined. The mechanical properties of recyclates were found to be comparable to or better than those of virgin material in all cases and conformed to industry standards for window profile. Contaminant removal stages significantly reduced the amount of large surface defects detected in extrudate. Processability was comparable to that of virgin compounds, but melt viscosity varied among different batches of recyclate, depending on the source and composition of the original PVC formulation.
26

Catalysts with Increased Surface Affinity for Chemical Recycling of PET Waste

ABEDSOLTAN, HOSSEIN 07 September 2022 (has links)
No description available.

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