Digitized by Kansas Correctional Industries

Orientador: José Antonio Perrella Balestieri / Banca: Mauricio Araújo Zanardi / Banca: Mateus Ricardo Nogueira Vilanova / Banca: Rogério José da Silva / Banca: José Rui Camargo / Resumo: Atualmente, a grande preocupação relacionada ao meio ambiente e redução do uso de combustíveis fósseis levou a comunidade acadêmica/científica a se concentrar em novas tecnologias de conversão de energia que possam garantir sua produção nos níveis necessários ao atendimento das necessidades humanas, mas considerando também os meios para minimizar os impactos ambientais. Propõe-se estabelecer o estado da arte da estrutura de geração termelétrica, conceituando a estrutura tecnológica de ciclos térmicos no mundo, caracterizada em centrais termelétricas distribuída e centralizada. São precedidos estudos termodinâmicos em centrais termelétricas de diferentes configurações, nas escalas industrial, municipal e nacional. Para fins de avaliação do desempenho de uma central térmica, é apresentado o desenvolvimento de uma modelagem térmica, utilizando ciclos combinados com gaseificação integrada (IGCC) e suas variações, usando balanço de massa, balanço de energia e balanço de exergia. Na geração distribuída em nível industrial, foi realizada uma análise no setor de papel e celulose, mostra-se que seu subproduto, o licor negro, um passivo ambiental, será mais bem aproveitado se passar por um processo de gaseificação e antes da queima em ciclo combinado em um sistema de cogeração. Na geração distribuída em escala municipal, o estudo de uma configuração de planta piloto foi elaborado para operar em empreendimento vinculado a alguma forma às cidades. Para o projeto de uma instalação piloto... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Currently, the major concern related to the environment and reduction of fossil fuels has led the academic/scientific community to focus on new energy conversion technologies that can guarantee production levels necessary to meet human needs, but also that consider the means to minimize environmental impacts. In this work, it is proposed to establish the state of the art of thermoelectric generation structure, conceptualizing the technological structure of thermal cycles in the world, in the context of distributed and centralized thermal power plants, as well as their technological characteristics. Thermodynamic studies are performed in thermal power plants of different configurations, considering scales in industrial, municipal and national levels. For the purpose of evaluating the performance of a thermal power plant, it is presented the development of a thermal modeling for combined cycles with an integrated gasification (IGCC) and their variations, using mass, energy and exergy system balances. In distributed generation at the industrial level, an analysis in the paper and pulp sector was held. It is shown that its by-product, the black liquor, an environmental liability, would be better used if sent through a process of gasification before being burned in a combined cycle cogeneration system. In distributed generation at the municipal level, the study of a pilot plant configuration is designed to operate in an enterprise linked to some form to the cities. For the design ... (Complete abstract click electronic access below) / Doutor

Thesis (M.S.)--Massachusetts Institute of Technology, Alfred P. Sloan School of Management, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND DEWEY. / Bibliography: leaves 58-59. / by Thomas J. Laslavic. / M.S.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

There is a critical need for inspection and condition monitoring of high temperature critical components such as pipelines and welds in electrical power generation and other plants operating at temperatures as high as 580°C. The high temperatures and pressures experienced in these pipelines, particularly for ageing plants lead to creep, fatigue and corrosion type defects. Safety of these plants is of paramount importance, and regular maintenance is carried out during planned outages at ambient temperatures. Ultrasonic non-destructive testing can be used to detect defects in the weld at ambient temperatures. However, at high operational temperatures, this technique cannot be applied due to the lack of high temperature transducers. This research has achieved significant advances towards enabling ultrasonic inspection and condition monitoring of high temperature critical points, by developing an ultrasonic transducer around an advanced piezoelectric single crystal material, called Gallium Orthophosphate (GaPO4), which can operate at the required temperature of 580°C. Based on its reported piezoelectric and other properties, and its commercial availability, GaPO4 was chosen as a candidate active material for application in a prototype high temperature transducer. In a series of confidence building tests with the selected piezoelectric material (electrical characterisation via the impedance method), it has been demonstrated that the GaPO4 piezoelectric elements are stable when subjected to 580°C for more than 600 hours. Ultrasonic thickness gauging has shown that GaPO4 works as a functional transducer generating and receiving ultrasound waves at 580°C for at least 360 hours. Furthermore, the sensitivity of the GaPO4 transducer to detect defects with simple geometry was successfully tested through measurements on steel blocks containing artificial defects (side-drilled holes) up to the same high temperatures. Based on the characterisation results from the impedance and ultrasonic measurements, a prototype ultrasonic transducer for operation at high temperatures has been designed and manufactured. The new ultrasonic transducer was tested in a laboratory environment using a steel calibration block, high temperature couplant, SONO 1100, and an electric furnace. In the range from ambient temperatures up to the target of 580°C, the ultrasonic transducer kept a signal-to-noise (SNR) level sufficiently high, above the threshold of 6 dB, which is high enough for practical non-destructive testing and condition monitoring.

Ao longo das últimas décadas, centenas de usinas hidrelétricas de todos os portes foram construídas no Brasil, sendo que as centrais hidrelétricas de pequeno porte foram os embriões deste desenvolvimento e recentemente assumiram papel de destaque com as mudanças ocorridas no setor elétrico iniciadas em meados dos anos 90. Através do estudo de aspectos técnicos que influenciam o custo-benefício de implantação de pequenas centrais hidrelétricas (PCHs) e da revisão bibliográfica de trabalhos anteriores que abordaram o assunto, a presente dissertação propõe uma sequência de etapas para avaliar de maneira preliminar e expedita a viabilidade de hidrelétricas entre 1 e 30 megawatts (MW). A metodologia de prospecção de PCHs é uma fase de estudo anterior ao inventário hidrelétrico e tem como objetivo estudar situações favoráveis e desfavoráveis à implantação de pequenas usinas, baseada em critérios técnicos, econômicos e socioambientais. A partir da coleta e organização dos dados da bacia hidrográfica a qual se pretende estudar, a metodologia sugere que sejam avaliados os condicionantes e restrições decorrentes de aspectos geológico-geotécnicos, socioambientais e de infraestrutura e logística. A partir desta análise, parte-se para a identificação de sítios com características atrativas, concepção de arranjos conceituais e definição da queda bruta, quando é ressaltada a utilização de modelos digitais de terreno (MDT). Posteriormente, procede-se para a avaliação da disponibilidade hídrica, oportunidade em que é destacado o uso de estudos de regionalização de vazões. Com base na queda bruta e nos estudos hidrológicos, devem ser elaboradas as estimativas da energia média produzida e potência instalada dos aproveitamentos identificados. Neste ponto, o trabalho apresenta uma discussão sobre parâmetros que podem ser facilmente obtidos através de estudos de regionalização de vazões para estimativa da energia média e, também, define uma faixa usual de fatores de capacidade de PCHs para o estabelecimento da potência instalada. O próximo passo consiste na avaliação econômica e, se necessária, uma visita que retroalimenta com novas informações a seqüência de etapas. Devido à variedade das informações espaciais necessárias, a metodologia é estruturada a partir de ferramentas de Sistemas de Informações Geográficas (SIG) que permitem relacionar e cruzar informações georreferenciadas, facilitando a organização e as análises necessárias. Como resultado da aplicação, é 7 possível a construção de um panorama abrangente dos principais aspectos que afetam o custo e o benefício de implantação das PCHs identificadas. Como forma de demonstrar e exemplificar a metodologia proposta foi desenvolvido um estudo de caso para a bacia do rio do Peixe, em Minas Gerais. Dessa forma, este trabalho visa contribuir com o setor elétrico brasileiro através de uma ferramenta que pode ser utilizada, tanto por órgãos públicos como entes privados, para o planejamento e maior conhecimento dos recursos energéticos, subsidiando a tomada de decisões de uma forma simples, rápida e de baixo custo. / Over the last the decades, hundreds of hydroelectric power plants of all sizes have been built in Brazil, with the small ones being the beginning of this development and recently having assumed an important position in the changes that happened in the electric sector in the mid-nineties. By studying the technical issues that influence the cost-benefit relation of installing small hydroletric power plants (SHPs) and through the analysis of previous papers that have studied the subject, the present dissertation proposes a sequence of steps in order to evaluate, preliminarily and quickly, the feasibility of hydroletric power plants with capacities from 1 to 30 MW. The SHP prospecting methodology is a previous study phase of hydroelectric inventory and its goals consist in studying favorable and unfavorable situations for the settlement of small hydroelectric power plants based on technical, economic and social- environmental criteria. By collecting and organizing the watershed data, the methodology suggests the evaluation of conditioners and restrictions from geological- geotechnical, social-environmental, infrastructure and logistics aspects. Based on this analysis, the next step is to identify attractive sites, design preliminary layout conception and define gross head, where the use of the digital terrain model (DTM) is prominent. Afterwards, it suggests the assessment of water availability, where it is possible to use regional flow estimate models. Based on gross head and hydrological studies, the mean energy production and installed capacity should be estimated. Furthermore, this work presents a discussion about parameters that could be easily obtained through the regional flow estimation models and, also, defines a range of usual capacity factors to establish the installed capacity of SHPs. The next step consists in an economic evaluation and a site visit that feeds the methodology with new information. Due to the variety of necessary spatial information, the methodology is structured by using the Geographic Information Systems (GIS) that allows relating and crossing information, making possible the organization and necessary analysis. As a result of application of the methodology, it is possible to build an extensive panorama of the main aspects that influence the cost and the benefit of the SHP sites that were identified. To demonstrate and exemplify the proposed methodology, a case study of the Peixe river watershed, in Minas Gerais, was developed. Thus, this work aims to contribute with the Brazilian electric sector through a tool that could 9 be used by public and private sectors in planning and to expand the knowledge about energetic resources, helping in decision making in a simple, quickly and cost efficient way.

Orientador: Celso Eduardo Tuna / Coorientador: José Luz Silveira / Banca: José Alexandre Matelli / Banca: Silvio Silvério da Silva / Resumo: A geração de energia elétrica em usinas termoelétricas de ciclo combinado tem se mostrado muito importante para o Brasil apesar de operar com custo maior do que a geração através de hidroelétricas. Neste trabalho, foram realizadas análises termoeconomica e ecológica, baseadas nos princípios da Termodinâmica (energia e exergia), aplicados em usina termoelétrica de ciclo combinado de 500 MW. Para este trabalho foram consideradas duas configurações para a planta: a primeira configuração é a padrão (sem considerar equipamento de redução de emissão de CO2), e a segunda que considera a implementação do processo de captura, armazenamento e compressão de CO2 (CAC). O principal objetivo do trabalho é estudar e comparara as diferenças nas eficiências termodinâmicas e ecológicas da planta (operando nas duas condições) e as alterações nos custos de produção de energia elétrica gerada, em vista da instalação do processo de CAC / Abstract: The Electric Power Generation in combined cycle power plants has been very important for Brazil despite having a higher cost than the generation through hydropower plants. In this work, there were performed thermeconomical and ecological analyzes, based on thermodynamic principles (energy and exergy) in a 500 MW combined cycle power plant. For this work there were considered two settings for this plant: first a standard configuration (without to consider equipments for CO2 emission reduction), and the second considering the implementation of a process of capture, storage and compression of carbon dioxide (CSC). The main objective of this analysis is to study and compare the differences in thermodynamic and ecological efficiencies (operating in both conditions) and the alterations in the electrical energy cost, in view of the installation of the CSC process / Mestre

Although the thermodynamic advantages of using solar energy to replace the bled off steam in the regeneration system of Rankine cycle coal fired power stations has been proven theoretically, the practical techno/economic feasibility of the concept has yet to be confirmed relative to real power station applications. To investigate this concept further, computer modelling software “THERMSOLV” was specifically developed for this project at Deakin University, together with the support of the Victorian power industry and Australian Research Council (ARC). This newly developed software simulates the steam cycle to assess the techno/economic merit of the solar aided concept for various power station structures, locations and local electricity market conditions. Two case studies, one in Victoria Australia and one in Yunnan Province, China, have been carried out with the software. Chapter one of this thesis defines the aims and scope of this study. Chapter two details the literature search in the related areas for this study. The thermodynamic concept of solar aid power generation technology has been described in chapter three. In addition, thermodynamic analysis i.e. exergy/availability has been described in this chapter. The “Thermosolv” software developed in this study is detailed in chapter four with its structure, functions and operation manual included. In chapter five the outcomes of two case studies using the “Thermosolv” software are presented, with discussions and conclusions about the study in chapters 6 and 7 respectfully. The relevant recommendations are then made in chapter eight.

The OSU/APEX thermal hydraulic test facility models the passive safety systems of the Westinghouse AP600 advanced light water reactor design. Numerous experiments have been performed to test these systems, the one of focus here is the station blackout scenario. This experiment simulated the complete loss of AC power to all plant systems. One of the objectives of this experiment was to determine the effectiveness of the Passive Residual Heat Removal (PRHR) system. The PRHR system removes heat by rejecting it into the In-containment Refueling Water Storage Tank (IRWST). The IRWST houses the PRHR and is used as a heat sink for the decay heat. The PRHR is a C-type tube heat exchanger. Heat is removed through two mechanisms: natural convection and nucleate boiling from the surface of the PRHR. As the experiment progressed, a large degree of thermal stratification was observed in the IRWST with no significant thermal mixing. A thermal layer developed in the top of the tank and as the thermal layer approached saturation the rate of heat removal from the sections of the PRHR engulfed by this layer decreased. The effectiveness of these sections of the PRHR continued to decrease until unexpected flow patterns developed at the same time that the thermal layer reached saturation. The IRWST fluid exhibited a bulk azimuthal flow pattern that increased the effectiveness of the PRHR. This increase allowed for more heat to be injected into the IRWST. However, the bulk fluid motion still did not mix the thermal layers. A three-dimensional computational fluid dynamic model using the CFX-4.2 software was developed to study the PRHR/IRWST system. The model uses the RPI method to account for the sub-cooled boiling that is present on the PRHR surface. The model successfully predicted the thermal stratification in the IRWST to within 4 K of experimental data. A counter-current flow was shown to occur along the interface of the thermal layers. This caused an enhancement of the heat transfer and turbulent mixing occurring across the interface of the thermal layers. / Graduation date: 1998

Thesis (M.Eng.)--Memorial University of Newfoundland, 2005. / Bibliography: leaves 88-91.