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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.
51

Rethinking Economics: Accounting for Environmental Impact at a Local Level

Wilson, Jeffrey 11 April 2013 (has links)
The quality of the human experience depends on a dramatic change in how we think about economics and, more specifically, about the relationship between human economic activity and the natural world. The continued pursuit of a growth agenda threatens the health and stability of global ecological systems, jeopardizes the wellbeing of many people, and undermines opportunities for future generations. In an era of sustainability challenges, we must measure the impacts of economic activity and use that information toward designing more sustainable human systems. This dissertation supports an ecological economic worldview by extending biophysical based measures to local scale applications to improve understanding of environmental impact at the urban and sub-regional scale. To account for environmental impact, I test two calculation approaches: one to estimate municipal ecological footprint values and one to measure environmental impact at a neighbourhood level. The novel calculation approaches account for environmental impact at finer scales of resolution than has traditionally been applied. I also explore drivers of environmental impact using Halifax Regional Municipality as a case study. I examine the relationship between direct GHG emissions and socio-economic and wellbeing variables using a multivariate model. Those reporting to be married, young, low income, and living in households with more people have correspondingly lower direct GHG emissions than other categories in respective groupings. Respondents with lifestyles that generate higher GHG emissions did not report to be healthier, happier or more connected to their communities, suggesting that individuals can experience similar degrees of wellbeing largely independent of their GHG emissions. I explored whether where we live influences direct GHG emissions. Findings indicate that individuals living in the suburbs generate similar GHG emissions to those living in the inner city, challenging a widely held assumption that living in the inner city is better for sustainability. These results underscore the importance of understanding the spatial distribution of GHG emissions at the sub-regional scale. The research offers new insights to measure and understand environmental impact at the local level toward supporting ecologically informed decision-making.
52

Analysis of Smart Grid and Demand Response Technologies for Renewable Energy Integration: Operational and Environmental Challenges

Broeer, Torsten 23 April 2015 (has links)
Electricity generation from wind power and other renewable energy sources is increasing, and their variability introduces new challenges to the existing power system, which cannot cope effectively with highly variable and distributed energy resources. The emergence of smart grid technologies in recent year has seen a paradigm shift in redefining the electrical system of the future, in which controlled response of the demand side is used to balance fluctuations and intermittencies from the generation side. This thesis investigates the impact of smart grid technologies on the integration of wind power into the power system. A smart grid power system model is developed and validated by comparison with a real-life smart grid experiment: the Olympic Peninsula Demonstration Experiment. The smart grid system model is then expanded to include 1000 houses and a generic generation mix of nuclear, hydro, coal, gas and oil based generators. The effect of super-imposing varying levels of wind penetration are then investigated in conjunction with a market model whereby suppliers and demanders bid into a Real-Time Pricing (RTP) electricity market. The results demonstrate and quantify the effectiveness of DR in mitigating the variability of renewable generation. It is also found that the degree to which Greenhouse Gas (GHG) emissions can be mitigated is highly dependent on the generation mix. A displacement of natural gas based generation during peak demand can for instance lead to an increase in GHG emissions. Of practical significance to power system operators, the simulations also demonstrate that Demand Response (DR) can reduce generator cycling and improve generator efficiency, thus potentially lowering GHG emissions while also reducing wear and tear on generating equipment. / Graduate
53

Three Essays on the Economics of Climate Change and the Electricity Sector

To, Hong Thi-Dieu 28 September 2011 (has links)
This doctoral thesis contains three essays on the economics of climate change and the electricity sector. The first essay deals with the subject of greenhouse gas (GHG) emissions and economic growth. The second essay addresses the issues of climate change policies, especially the role of the emergent innovative technologies, and the restructuring of the electricity sector. The third essay presents a model of transmission investments in electric power networks. Chapter One studies the impacts of climate change on economic growth in the world economies. The paper contains explicit formalization of the depletion process of exhaustible fossil fuels and the phase of technology substitution. The impacts of climate change on capital flows and welfare across countries are also investigated. The restructuring of the electricity sector is studied in Chapter Two. It also analyzes how climate change policies can benefit from emergent innovative technologies and how emergent innovative technologies can lower GHG emissions. It is shown that the price of electricity is strictly rising before emergent innovative firms with zero GHG emissions enter the market, but strictly declining as the entry begins. In Chapter Three, a model of electricity transmission investments from the perspective of the regulatory approach is formulated. The Mid-West region of Western Australia, a sub-system of the South West Interconnected System is considered. In contrast with most models in the literature that deal only with network deepening, this model deals with both network deepening and network widening. Moreover, unlike the conventional investment models which are static and deal only with the long run, this model is dynamic and focuses on the timing of the infrastructure investments. The paper is a study of an optimal transmission investment program which is part of the optimal investment program for an integrated model in which investments in transmission and investments in generation are made at the same time.
54

Greehouse Gas Simulations in Munich : Investigation of Wind Averaging Techniques for analysis of column measurements (XCO2) using CFD

Pawa, Diptesh January 2018 (has links)
The underlying objective of this thesis was to perform GHG simulation studies to predict the dispersion and transport of greenhouse gases emitted from a thermal power plant in order to assess the extent of dangerous living environment for those surrounding it in case of an unforeseen calamity. The research carried out during this thesis was to investigate the method of wind averaging techniques to analyse column measurements (XCO2). The reason for adopting this method of analysis was to correlate the physical aspect of wind data to average over a certain period of time wherein the amount of XCO2 (in ppm) observed displays values greater than the background concentration. CFD simulations were performed using the open source code, OpenFOAM, and steady RANS models modified with turbulence boundary conditions for the urban environment case with previously validated simulation studies carried out for the same region in Munich, Germany. Initial results performed during the testing stage indicated that maximum average XCO2 value (in ppm) was recorded at the lowest value of mean wind speed and at a more downwind location of the measurement site. The results obtained from simulation studies on comparison with experimental values (arithmetic average) also suggest that for the same time interval, the difference in values for similar wind conditions as mentioned before makes this technique a more favourable choice for comparison and verification at another time instant.  There have been recent developments in GHG simulation based studies and however the current method does represent certain drawbacks, an insight into performing averaging analysis at time intervals representing peak XCO2 moments could be demonstrated which can also help in reducing the overall number of simulations as well as provide information with respect to mitigation measures based on transport and diffusion behavior.
55

Quantifying the energy consumption of the water use cycle

Trujillo, Iliana Cardenes January 2017 (has links)
The management and delivery of water and wastewater consume significant amounts of energy, mostly in the form of electricity. With increasing populations, climate change, water quality issues and increasing energy prices, it is more important than ever to understand energy consumption patterns. Energy usually represents the largest operational cost in water utilities around the world, yet there is limited work aiming to quantify the specific relationship between water and its associated energy, and understand its implications for future decision-making. This thesis presents variousmethodological approachesto quantify and understand energy use in water infrastructure systems, as well as how to incorporate them in decision-making processes. The main hypotheses are as follows: firstly, a detailed understanding of the use of energy in water infrastructure systems can facilitate more efficient and sustainable water infrastructure systems and, secondly, that incorporating energy into planning for water and wastewater resources can help understand the impacts of decisions and establish trade-offs between actions. To test these hypotheses, the thesis presents an analytical approach to various areas. Firstly, it identifies, maps and quantifies the energy consumption patterns within a water infrastructure system. This is then used to identify inefficiencies and areas of potential energy saving. Secondly, it incorporates detailed energy costs into short and long-term water resources management and planning. Thirdly, it evaluates trade-offs between energy costs and changing effluent quality regulations in wastewater resources. The Thames River basin, in the south-east of England, is used as a case study to illustrate the approach. The results demonstrate that a systematic approach to the quantification of energy use in a water infrastructure system can identify areas of inefficiencies that can be used to make decisions with regards to infrastructure planning. For example, water systems have significant geo-spatial variations in energy consumption patterns that can be addressed specifically to reduce negative trade-offs. The results also show that incorporating detailed energy information into long-term water resources planning can alter the choices made in water supply options, by providing more complete information. Furthermore, methodologically, they show how several methodological approaches can be used to support more complete decision-making in water utilities to reduce short and long-term costs. In this particular case study, the results show that there are important differences in energy consumption by region, and significant differences in the seasonal and energy patterns of water infrastructure systems. For example, water treatment was shown to be the largest consumer of energy within the whole system, compared with pumping or wastewater treatment; but wastewater treatment energy consumption was shown to be the fastest growing over time due to changes in water quality regulatory frameworks. The results show that more stringent effluent standards could result in at least a doubling of electricity consumption and an increase of between 1.29 and 2.30 additional million tonnes of CO2 a year from treating wastewater in large works in the UK. These are projected to continue to increase if the decarbonisation of the electricity grid does not occur fast enough. Finally, the thesis also shows that daily energy consumption can be reduced by up to 18% by optimally routing water through a water network. optimization of water networks, and that a change in discount rates could change the daily operating costs by 19%, that in turn leads to a resulting different set of optimal investment options in a water supply network.
56

Balanço de carbono e nitrogênio e emissão de gases de efeito estufa em sistema integrado de produção agropecuária com ovinos / Carbon and nitrogen balance and emission of greenhouse gases in an integrated system of agricultural production with sheep

Cruz, Igor Vilela [UNESP] 25 February 2016 (has links)
Submitted by IGOR VILELA CRUZ (igorv_cruz@hotmail.com) on 2017-08-24T00:41:35Z No. of bitstreams: 1 Dissertação Normas 2017 - Modelo.docx: 3338687 bytes, checksum: 46e5af3e4a40a266341324a8a2c89512 (MD5) / Rejected by Luiz Galeffi (luizgaleffi@gmail.com), reason: Solicitamos que realize uma nova submissão seguindo as orientações abaixo: A versão final da dissertação/tese deve ser submetida no formato PDF (Portable Document Format). O arquivo PDF não deve estar protegido e a dissertação/tese deve estar em um único arquivo, inclusive os apêndices e anexos, se houver. Por favor, corrija o formato do arquivo e realize uma nova submissão. Agradecemos a compreensão. on 2017-08-25T14:10:07Z (GMT) / Submitted by IGOR VILELA CRUZ (igorv_cruz@hotmail.com) on 2017-08-28T19:02:27Z No. of bitstreams: 2 Dissertação Normas 2017 - Modelo.docx: 3338687 bytes, checksum: 46e5af3e4a40a266341324a8a2c89512 (MD5) Dissertaçao Igor PDF.pdf: 2226362 bytes, checksum: cb218002197fae589f8f935e304ed8a0 (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-08-29T14:16:57Z (GMT) No. of bitstreams: 1 cruz_iv_me_bot.pdf: 2226362 bytes, checksum: cb218002197fae589f8f935e304ed8a0 (MD5) / Made available in DSpace on 2017-08-29T14:16:57Z (GMT). No. of bitstreams: 1 cruz_iv_me_bot.pdf: 2226362 bytes, checksum: cb218002197fae589f8f935e304ed8a0 (MD5) Previous issue date: 2016-02-25 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Como opção para produção de silagem, o consórcio do milho com o capim-marandu e o feijão-guandu pode aumentar a quantidade de silagem produzida, sendo essa de melhor qualidade. O consórcio entre gramíneas e leguminosas pode ser uma estratégia interessante para aumentar os estoques de C e N e a quantidade forragem pelas pastagens cultivadas em sucessão, que resultarão em palhada para cobertura do solo no Sistema Plantio Direto (SPD). Em sucessão aos consórcios de verão, a aveia se torna uma opção importante, principalmente pela possiblidade de sobressemeadura, o que torna viável o seu cultivo por produtores que não tem acesso à semeadoras específicas para sementes miúdas. Objetivou-se com esse trabalho avaliar a produção de fitomassa aérea das espécies cultivadas, em função da presença ou não do feijão-guandu em consórcio com milho e capim marandú no verão para produção de silagem, e também em função das modalidades de semeadura da aveia-preta no outono-inverno para produção de pasto e palha, em SPD, com integração Lavoura-Pecuária (iLP), visando a terminação de cordeiros em semi-confinamento. Além disso, verificar se as emissões de gases de efeito estufa (GEE) por esses cultivos são compensados por aumentos no aporte de C no solo. A presente pesquisa foi realizada, na Fazenda Experimental Lageado, pertencente à Faculdade de Ciências Agronômicas – UNESP, localizada no município de Botucatu (SP), e foi conduzido nos anos agrícolas 2013/2014 e 2014/2015. O delineamento experimental foi em blocos casualizados, em parcela subdividida, com dois fatores (A e B) e 4 repetições. O fator A está alocado na parcela principal e constituído de dois tratamentos de verão, ou seja, duas modalidades de cultivo da cultura do milho para ensilagem, uma em consórcio com capim-marandu (Brachiaria brizantha (Hochst. ex A. Rich.) Stapf cv. Marandu [syn. Urochloa brizantha (Hochst. ex A. Rich.) R. D. Webster cv. Marandu] e a outra em consórcio com capim-marandu e feijão-guandu cv. BRS Mandarim. O fator B é alocado na subparcela e constituído de dois tratamentos de inverno, ou seja, duas modalidades de semeadura de aveia preta (Avena bysantina), uma a lanço (manual) e a outra em linha. Foi avaliado a qualidade e quantidade de silagem produzida, os teores de C e N no solo, o aporte sobre o solo de matéria seca, C e N pelos resíduos vegetais e os fluxos de gases de efeito estufa (CO2, N2O e CH4 provenientes do solo). Para comparação entre os tratamentos foi realizada análise de variância e as médias foram comparadas estatisticamente pelo teste t, no nível de 5 % de probabilidade de erro. As emissões de GEE foram maiores em outubro de 2014 logo após o pastejo, sendo o solo fonte de CH4. O cultivo do feijão-guandu resultou em maior aporte de resíduos vegetais sobre o solo, sendo esses resíduos com menor relação C/N. / Optionally for silage production, the intercrop of corn with the marandugrass and pigeon pea can increase the amount of produced silage, and this best quality. The consortium of grasses and legumes can be an interesting strategy to increase the stocks of C and N and the amount forage for pastures grown in succession, which will result in straw for mulching in no-tillage system. In succession to summer intercrop, oats becomes an important option, especially the possibility of overseeded, making it possible its cultivation by farmers who do not have access to specific seeders for small seeds. The objective of this study was to evaluate the air biomass production of cultivated species, depending on the presence or absence of pigeon pea intercropped with corn and pasture in the summer for silage, and also depending on the seeding arrangements for aveia- yellow in autumn-winter pasture production and straw in SPD with Crop-Livestock integration, aimed at terminating lambs in semi-confinement. Also, check if emissions of greenhouse gases (GHG) by these crops are offset by increases in the C input to soil.This survey was conducted in the Experimental Farm Lageado, belonging to the Faculty of Agricultural Sciences - UNESP, located in Botucatu (SP), and was conducted in the agricultural year 2014/2015. The experimental design is a randomized block in a split plot with two factors (A and B) and 4 repetitions, Factor A is allocated in the main plot and consists of two summer treatments, ie two crop cultivation modes corn for silage, one in consortium with marandugrass and the other in consortium with marandugrass and pigeon pea cv. BRS Mandarin. Factor B is allocated in the sub-plot and comprises two winter treatments, ie two types of hp yellow oat sowing. Sao Carlos (Avena bysantina) a broadcasted (manually) and the other in line. It was the quality and quantity of produced silage rated. The gas samples for determination of CO2 flows, N2O and CH4 from the soil were carried out after grazing oats, and during regrowth of braquiaria in 2014, during the grazing in 2014 was isolated an area within the plot, and shortly after the end of the grazing cycle were installed two chambers, 1 in the area that was not grazed. The second round of collection was after planting oats in 2015. Overall GHG emissions were higher in October 2014 soon after grazing, and the ground source of CH4, the desetos animals and quality and quantity of straw in influencied emissions. The treatments with a light harrowing for merger of oats, obtained the highest values of lower values of PPA.It was analyzed the stock of C and N in the 0-40 cm depth in the soil and plants and straw, to determine the balance of Generally the treatment with the legume submitted a C / N ratio smaller but with a greater contribution to the treatment plant without the legume. This sense labor objective was to evaluate the Greenhouse Gas Emissions Greenhouse in function of the use of different Systems Integration Crop Farming and as emissions of fluorinated gases can be compensated hair increase of C stocks in soil and straw with these practice managements. / FAPESP: 2013/23853-9
57

Contribuição da produção confinada de suínos na emissão de amônia e gases de efeito estufa mediante avaliação das metodologias continua e simplificada / Contribution of swine confined production in ammonia emissions and greenhouse effect gases through evaluation of continuous and simplified methodologies

César Augusto Pecoraro 04 February 2015 (has links)
O impacto ambiental gerado pelas atividades pecuárias sobre o meio ambiente desperta cada vez mais atenção para estudos de avaliação do potencial poluidor das atividades. Essas atividades contribuem significativamente para as emissões de amônia e gases de efeito estufa. A amônia por sua vez contribui para a eutrofização e acidificação dos ecossistemas. Gases de efeito estufa (GEE), incluindo o dióxido de carbono (CO2), metano (CH4), óxido nitroso (N2O) e vapor de H2O são considerados os principais gases responsáveis pelo mecanismo de aquecimento global e as alterações climáticas. Atualmente, a carne suína é a mais consumida no mundo, estima-se que seu consumo aumentará nos próximos anos e, para atender esta demanda, os sistemas produtivos de suínos deverão ampliar sua capacidade produtiva para abastecer o mercado consumidor crescente. A avaliação ambiental dos sistemas de produção de suínos torna-se essencial para garantir a sustentabilidade do setor. Assim, pelo exposto, essa pesquisa tem como objetivo caracterizar as emissões de amônia e gases de efeito estufa em uma unidade de produção de suínos na fase fisiológica de crescimento e terminação utilizando duas metodologias: a contínua e a simplificada. Além disso, pretendemos verificar os resultados obtidos pelas duas metodologias por meio do balanço de nutrientes: este permite avaliar a coerência dos dados obtidos pelas duas metodologias. E por fim, correlacionar as emissões gasosas à variável climática temperatura. O estudo foi desenvolvido em uma granja comercial, no município de Concórdia - SC. A mensuração dos gases foi realizada segundo as recomendações das metodologias: contínua e simplificada. As concentrações dos gases no ar foram mensuradas pelo analisador de gás (INNOVA 1412). As emissões gasosas médias foram calculadas considerando a taxa de ventilação e as diferenças de concentração de gases entre o ar interior e exterior da instalação. O fluxo de emissão obtido pela metodologia simplificada em [g. suíno-1. hora-1] foram 2,689 para o CO2, 0,30 para o N2O, 4,39 para o CH4, 13,55 para o NH3 e 3,273 para água. O fluxo obtido para a metodologia contínua em [g. suíno-1. hora-1] foi de 574 para CO2, 0,67 para o N2O, 19,50 para o CH4, 5,84 para o NH3 e 7,239 para vapor de água. Em comparação ao balanço de massa, a metodologia simplificada apresentou maior coerência em relação aos dados obtidos. / The environmental impact caused by the livestock activities is increasing the number of researches about it, taking into consideration the pollution effects in the environment. The agricultural activities have a great contribution to ammonia\'s and greenhouse gases\' emissions. Ammonia contributes to eutrophication and acidification of ecosystems. Greenhouse gases (GEE), including CO2, CH4, N2O and vapour of H2O are considered the main responsible gases for the global warming and the climate changes. Nowadays, the pig flash is the most consumed one worldwide and this consume tends to continue increasing in the next years. In order to attend this request, the swine production systems must extend their productive capacity to supply the consumer market. The environmental evaluation of swine production systems has been considered essential to guarantee the sustainability of this sector. Taking into consideration this situation, this research aims at characterizing the ammonia\'s and greenhouse gases\' emissions in one swine production installation in the growth physiological stage and in the terminating stage, basing ourselves in two methodologies: the continuous and the simplified ones. Furthermore, we aim at verifying the obtained results by these two methodologies, through nutrient balance: this one enables to evaluate the data\'s consistency using both methodologies. And finally, we objective to correlate the gas emissions to the temperature (climatic variable). This research was developed in commercial farm in Concórdia - SC. The gas mensuration was accomplished by the two cited methodologies: the continuous and the simplified. The concentrations of gases in the air were measured by the gas analyzer (INNOVA 1412). The average gas emissions were estimated, taking into consideration the ventilation rate and the concentration differences of gases between the interior and exterior part of the installation. The emission flow obtained by the simplified methodology in [g. swine-1. hour-1] was 2,689 to CO2, 0,30 to N2O, 4,39 to CH4, 13,55 to NH3 and 3,273 to water. The emission flow obtained by the continuous methodology in [g. swine-1. hour-1] was 574 to CO2, 0,67 to N2O, 19,50 to CH4, 5,84 to NH3 and 7,239 to water vapor. Comparing theses values to the mass balance, the simplified methodology presented a greater consistency in relation to the obtained data.
58

Redução dos impactos ambientais causados por emissões de gases no transporte marítimo. / Reduction of the environmental impacts caused by the maritime transport.

Juan Carlos Montoya Cisneros 07 November 2011 (has links)
O transporte marítimo depende essencialmente da energia dos derivados do petróleo e, em conseqüência, produz emissões de CO2, SOX, NOX e material particulado entre outros. Hoje o transporte aquaviário responde por aproximadamente 4,5% das emissões de carbono, 4% das emissões de óxidos de enxofre e 7% das emissões de oxido de nitrogênio. Se a expansão desse modal de transporte se mantiver nos próximos anos, como se tem previsto, a sua participação na emissão destes tipos de poluentes deve aumentar e, certamente, haverá pressões da sociedade para introdução de medidas que contenham esse aumento. Pode-se afirmar que os poluentes gerados pelo Transporte Marítimo são resultado de deficiência em projeto de navios e de seus sistemas, de uma má gestão operacional, e inclusive da ausência de medidas de regulamentação mais rigorosas. O estudo se concentra em estudar dois destes pontos. O primeiro se refere ao desenvolvimento do projeto do navio e da instalação propulsora com a preocupação de reduzir o consumo de energia. Isso implica em alterações nos projetos e seus sistemas de propulsão, tirando melhor proveito da tecnologia disponível no mercado, bem como análise da viabilidade de uso de fontes alternativas de energia. O segundo ponto se refere ao processo de gestão operacional, com ênfase na redução da emissão de poluentes. Serão examinados exemplos práticos que sustentem as reduções e benefícios, por exemplo, a redução de velocidade do navio. Por ultimo foram expostas as alternativas que o autor considera as mais promissoras para atingir o objetivo pretendido. São selecionadas as melhores opções que contribuem para a redução das emissões de gases, entre as medidas tecnológicas, operacionais e de dimensionamento de frota. Algumas destas alternativas podem ser aplicadas aos navios existentes, enquanto que outras só podem ser aplicadas no projeto de navios novos. / The shipping depends on the energy of oil products, which produce emissions of CO2, SOX, NOX and particulate matter. Today, the water transport accounts for approximately 4.5% of carbon emissions, 4% of sulfur oxides emissions and 7% of nitrogen oxide emissions. If the expansion of this mode of transport is maintained in the coming years, as has been predicted, its participation in the emission of these types of pollutants must increase, and certainly there will be pressure from society for introducing measures to contain its increase. It can be argued that pollutants generated by the Maritime Transport are the result of deficiency in the design of ships and theirs systems, deficient operational management, and even the absence of more stringent regulatory measures. The study focuses on the study of these two points. The first refers to the development of Ship design and propulsion plant with a view to reducing energy consumption. This implies changes in design and propulsion systems, making best use of available technology, as well as the evaluation of viability in the use of sources of alternative energy. The second point refers to the process of operational management, with emphasis on reducing of emissions. Practical examples are examined to support and benefit the reductions of emissions, for example, the reduction of ship speed. Finally is exposed the alternatives that the author considers the most promising to achieve the desired goal. The best options are selected to reducing greenhouse gas emissions between technological measures, operational and fleet sizing. Some of these alternatives can be applied to existing ships, while others may only be applied in the design of new ships.
59

Estudo experimental da regeneração termica de areia de macharia em leito fluidizado / Experimental study of waste core sand thermal reclamation in fluidized bed.

Oliveira, Julio Cesar Dainezi de 27 February 2007 (has links)
Orientador: Arai Augusta Bernardez Pecora / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-09T20:35:15Z (GMT). No. of bitstreams: 1 Oliveira_JulioCesarDainezide_D.pdf: 2306181 bytes, checksum: 7bfd18a72e99a2fe132735e0d81349f7 (MD5) Previous issue date: 2007 / Resumo: Esta pesquisa relata um estudo experimental do processo de regeneração térmica de areia de macharia descartada em um incinerador de leito fluidizado. Os objetivos foram: 1) caracterizar as propriedades da areia de macharia descarta ante e depois do processo de incineração e comparar com as propriedades da areia nova; e 2) avaliar as emissões de monóxido de carbono e de hidrocarbonetos totais. Os efeitos das seguintes variáveis sobre as propriedades da areia descartada de macharia e as emissões gasosas foram avaliados: temperatura do leito, excesso de ar e inventário. Para obter os dados experimentais foi utilizado um planejamento fatorial, onde o erro experimental foi avaliado através de três repetições no ponto central. Os experimentos foram realizados em condições de regime permanente. Os resultados experimentais mostraram que o incinerador apresentou excelente uniformidade térmica e bom controle de temperatura e queda de pressão. O resultado da análise estatística mostrou que não houve influência significativa de nenhuma das variáveis sobre as propriedades da areia regenerada. Porém, houve diferença significativa entre as propriedades da areia nova e regenerada, das quais o teor de finos foi o mais afetado pelo tratamento térmico e mecânico. A operação com excesso de ar foi muito efetiva na diminuição das emissões de monóxido de carbono e de hidrocarbonetos totais. O efeito da temperatura do leito sobre as emissões gasosas foi contraditório. Enquanto a temperatura do leito foi aumentada, as emissões de monóxido de carbono diminuíram, por outro lado, as emissões de hidrocarbonetos totais aumentaram também / Abstract: This investigation reports an experimental study of the thermal regeneration process of core sand waste in a fluidized bed incinerator. The objectives were: 1) to characterize of core sand waste properties before and after the incineration process and comparing with the new sand properties; and 2) to evaluate of carbon monoxide and total hydrocarbon emissions. The effects of following variables on core sand waste properties and the gases emitted were evaluated: bed temperature, excess air and inventory. To obtain experimental data a factorial design technique was used, where the experimental error was evaluated with three repetitions at the central point of the domain. Experiments were conducted at steady state conditions. The experimental results showed that the fluidized bed incinerator offer excellent thermal uniformity and good temperature and pressure drop control. The result of the statistical analysis showed that there was no significant influence of the three variables on the reclaimed sand properties. However there was significant difference between the properties of new sand and reclaimed sand, of which the fines concentration was the most affected by thermal and mechanical treatments. The excess air operation was very effective in lowering the carbon monoxide and total hydrocarbon emissions. The effect of bed temperature on gases emissions was discordant. While bed temperature is increased, the carbon monoxide decreases, on the contrary, the total hydrocarbon emissions increased too / Doutorado / Termica e Fluidos / Mestre em Engenharia Mecânica
60

Estudo experimental da transferencia de calor suspensão gas/solido : parede em leito fluidizado circulante / Experimental study of the suspension to surface heat transfer in a circulating fluidized bed.

Herrera Camacho, Lyda Margarita 07 August 2008 (has links)
Orientador: Arai Augusta Bernardez Pecora / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-11T11:34:09Z (GMT). No. of bitstreams: 1 HerreraCamacho_LydaMargarita_M.pdf: 1762236 bytes, checksum: c6b9125be4a28906691da985c3fb676e (MD5) Previous issue date: 2008 / Resumo: O propósito desta pesquisa foi o estudo experimental da transferência de calor suspensãoparede em um leito fluidizado circulante em escala piloto. Foi escolhido um modelo de planejamento experimental denominado delineamento composto central rotacional, visando verificar a influência de três variáveis: temperatura do leito, inventário de sólidos e velocidade superficial do ar no coeficiente de transferência de calor suspensão-parede. Os testes foram executados usando como material particulado areia quartzosa industrial com diâmetro médio de m µ 356 . Um total de dezoito testes foi executado para cinco temperaturas do leito (250 a 400°C), cinco velocidades superficiais do ar (5 a 7m/s) e cinco inventários de sólidos (7 a 9 Kg). O trocador de calor estudado foi do tipo tubo duplo com folga anular de 47,3 mm, o qual utiliza como fluido de resfriamento água escoando paralelamente à suspensão gás-sólido. Os resultados experimentais mostraram que os fatores temperatura do leito e inventário de sólidos apresentaram as maiores influências sobre o coeficiente de transferência de calor, enquanto a velocidade superficial do gás apresentou um pequeno efeito. Os resultados experimentais foram comparados com três modelos teóricos, encontrando-se que a melhor correspondência com os resultados foram obtidos pela aplicação do modelo do pesquisador BASU (1989). Foi proposta uma correlação simples para previsão do coeficiente de transferência de calor em leito fluidizado circulante, válida para as faixas de operação testadas neste trabalho / Abstract: The purpose of this research was the experimental study of the suspension to surface heat transfer in a pilot scale circulating fluidized bed system. A Rotational Composite Central Design of experiments was applied in order to verify the influence of three important factors: bed temperature, gas fluidization velocity and solids inventory on suspension to surface heat transfer coefficient. Experiments were done using quartz sand, m µ 356 mean diameter as solid material and air as fluidization gas. A total of eighteen tests were performed for five riser temperatures (250 to 400°C), five gas fluidization velocities (5 to 7m/s) and five solids inventory (7 to 9 Kg). The experimental system is composed of a riser 102 mm internal diameter and 4 m height and a downcomer with 63 mm internal diameter. The studied heat exchanger, double pipe type, is located at the riser; 1000 mm above the gas entrance and presents a cooling water flow through a 47,3 mm annular space. Experimental results showed that the riser temperature and the solids inventory presented more influence on the suspension to surface heat transfer coefficient than the superficial gas velocity. The experimental results were compared with three theoretical models and the results showed that the best agreement occurred for the BASU (1989) model. A simple correlation was proposed to calculate the suspension to surface heat transfer coefficient as a function of the three studied influence factors to be applied inside the variables range studied. / Mestrado / Termica e Fluidos / Mestre em Engenharia Mecânica

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