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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.
11

Modelo preditivo da emissão e dispersão do NOx gerado em usinas termoelétricas como instrumento de análise de inserção e capacidade de suporte regional da qualidade do ar. / Emission and predictive model of NOx from thermal power plants as an analysis tool of insertion and regional sustainable of air quality.

Jean Cesare Negri 02 September 2002 (has links)
O trabalho procura sistematizar de forma metodológica a análise da inserção de uma usina termoelétrica no contexto do planejamento, no âmbito regional, sob o ponto de vista de impacto ambiental atmosférico. O método de previsão indica a primeira estimativa da condição regional, alternativo ao método convencional de medição, sobretudo em regiões carentes de informações. Baseado em informações disponíveis em banco de dados e uma análise preliminar da região de influência do empreendimento, é estimada a carga de poluentes atmosféricos existentes (poluição de fundo). As taxas de emissão por fonte são obtidas através de fatores de emissão, enquanto que a qualidade do ar é obtida por modelo de dispersão. O impacto da nova usina é incluído no modelo para avaliar o acréscimo. O modelo foi aplicado na análise de emissão e dispersão de NOx, sendo desenvolvido um estudo de caso para a região de Paulínia em São Paulo. / This paper intends to introduce a methodology to analyze the insertion of a Thermal Power Plant (TPP ) within a planning environmental phase from the viewpoint of air pollution impact, focusing the regional ambiance. The prediction methodology indicates the first regional condition estimative, as an alternative to the monitoring conventional one, mainly in region without information. Based on available data basis information and preliminary analysis of the region affected by the TPP, the local pollutants are estimated (background pollution). The source emission rates are calculated through emission factors while the air quality is obtained by using a dispersion model. The impact of the new TPP is added to the model to evaluate the emission growth. The predictive and dispersion model for NOx is synthesized and applied in a case study that considers Paulínia region in State of São Paulo.
12

Caracterização petrológica e química dos carvões utilizados em usinas termelétricas brasileiras e as cinzas geradas no processo de combustão

Brown, Matthew Thomas January 2011 (has links)
Neste estudo, amostras de carvão (feed coal), cinzas pesadas e cinzas leves, amostradas pelo intervalo de 3 a 4 meses no período um ano, de usinas termelétricas localizadas no sul do Brasil (Candiota (RS), Charqueadas (RS), São Jerônimo (RS) e Jorge Lacerda (SC)) foram analisadas e comparadas. As amostras de carvão foram caracterizadas pela análise petrológica (reflectância da vitrinita e análise macerais), análise química (imediata e elementar), determinação do poder calorifico, difração de raios X e espectrometria micro-Raman. As amostras de cinzas pesadas e leves foram analisadas por difração de Raios X, carbono total (CT) e métodos petrológicos. A análise de reflectância da vitrinita mostrou que os carvões utilizados em usinas termelétrica do Rio Grande do Sul têm um rank subbetuminoso, enquanto o carvão de Jorge Lacerda (SC) é composto de uma mistura de carvões com níveis de rank que variaram de subbetuminoso até meta-antracita, mas que são predominantes de betuminoso alto volátil. A análise de macerais mostrou que vitrinita e inertinita foram os grupos de macerais predominantes em todas as amostras de carvão. As misturas de carvão de Jorge Lacerda são caracterizadas pelas diferentes populações de vitrinita, turfa e coque de petróleo. A análise imediata mostrou que todos os carvões têm elevado teor de cinzas, com valores médios de: 49% (p/p) para Candiota, 47,6% (p/p) para Charqueadas, 38,9% (p/p) para São Jerônimo e 40,5% (p/p) para Jorge Lacerda. A análise elementar apresentou valores médios de enxofre de: 1,4% (p/p) para carvões de Candiota, 0,9% (p/p) de Charqueadas, 0,7% (p/p) de São Jerônimo e 2,0% (p/p) de Jorge Lacerda. Os valores médios de poder calorífico foram: 2928 cal/g para Candiota, 3156 cal/g para Charqueadas, 3834 cal/g para São Jerônimo e 4510 cal/g para Jorge Lacerda. A matéria mineral determinada pela difração de raios X consistiu principalmente de quartzo e caolinita. A matéria mineral das cinzas pesadas e leves, determinada por difração de raios X, consistiu predominantemente de quartzo e mulita. Os valores médios do CT nas cinzas pesadas e leves foi: 0,66 e 0,35% (p/p) para Candiota, 10,11 e 1,17% (p/p) para Charqueadas, 16,97 e 9,34% (p/p) para São Jerônimo e 2,47 e 0,99% (p/p) para Jorge Lacerda respectivamente. A composição da matéria mineral das amostras de cinzas consistiu na sua maioria de vidro e esferas de espinélio. Crassisphere e crassinetworks, derivados de vitrinita, foram as partículas de char mais comuns observadas nas amostras de cinzas, bem como partículas de mixed dense e solid/fusinoid, derivadas de macerais de inertinita.Espectrometria micro-Raman foi utilizada para observar diferenças entre os grupos de macerais das amostras de carvão neste estudo e entre vitrinitas de carvões com rank diferentes. Os espectros Raman da vitrinita e inertinita foram semelhantes, porém a vitrinita apresentava maior deslocamento Raman do pico – D e o pico – G apresentava uma largura maior. O espectro obtido para liptinita consistiu de alta fluorescência, sem picos significativos. Em relação o rank de carvão, as larguras dos picos G e D tornaram-se menores com aumento da reflectância da vitrinita. / In this study feed coal, bottom ash and fly ash from coal-burning power plants located in southern Brazil (Candiota (RS), Charqueadas (RS), São Jerônimo (RS) and Jorge Lacerda (SC)) were collected in intervals of three to four months over a period of one a period of one year and analyzed by petrological and chemical methods. Analyses on the feed coal samples included the following: petrological (vitrinite reflectance and maceral analysis) chemical (proximate and ultimate analyses, determination of calorific values) and mineralogical (X-ray diffraction and Raman micro-spectrometry). Analyses on bottom and fly ash samples included X-ray diffraction, total carbon (TC) and petrological methods.The petrological analyses showed that the coals from Rio Grande do Sul have a rank of: subbituminous, while the coal from Jorge Lacerda is composed of a blend of coals with ran levels that ranged from subbituminous to meta-anthracite, with a predominance of high volatile bituminous coal. The maceral analysis showed that vitrinite and inertinite were the dominate maceral groups in the coals. The coal blends from Jorge Lacerda were composed of different vitrinite populations and also included peat and petroleum coke. The proximate analysis showed that the coals have high ash content, with average values of: 49.0% wt. for Candiota, 47.6% wt. for Charqueadas, 38.9% wt. for São Jerônimo and 40.5 for Jorge Lacerda. The ultimate analysis showed average sulfur values of: 1.4% wt. for Candiota, 0.9% wt. for Charqueadas, 0.7% wt. for São Jerônimo and 2.0% wt. for Jorge Lacerda. The average calorific values were: 2928 cal/g for Candiota, 3156 cal/g for Charqueadas, 3834 cal/g for São Jerônimo and 4510 cal/g for Jorge Lacerda. The mineral matter consisted of mainly quartz and kaolinite, as determined by X-ray diffraction. The mineral matter of the bottom ash and fly ash, as determined by X-ray diffraction, consisted predominately of quartz and mullite. The average values of the TC in the bottom ash and fly ash was determined to be: 0,66 wt.% and 0,35 wt.% for Candiota, 10,11 wt.% and 1,17 wt.% for Charqueadas, 16,97 wt.% and 9,34 wt.% for São Jerônimo and 2,47 wt.% and 0,99 wt.% for Jorge Lacerda respectively. The mineral matter of the ash samples consisted mostly of glass and spinel spheres. Crassisphere and crassinetworks, derived from vitrinite, were common char particles observed in the ash samples, as well as mixed dense and solid/fusinoid, particles derived from inertinite macerals. Ash samples from São Jerônimo contained several unburnt coal particles, while samples from Jorge Lacerda contained solid particles derived from petroleum coke.Raman spectrometry was used to characterize the coal samples in this study, with respect to the different maceral groups and changes in coal rank. The Raman spectra of vitrinite and inertinite were similar with the exception that vitrinite had higher D- peak wave numbers and the G-peaks were wider. The spectrum obtained for liptinites consisted of a high background florescence, without significant peaks. With increasing coal rank, the widths of the G and D-peaks become smaller.
13

Decisões baseadas em risco - método aplicado na indústria de geração de energia elétrica para a seleção de equipamentos críticos e políticas de manutenção. / Risk-based decision making - method apllied on electrical power generation industry for critical equipment and maintenance policy selection.

Guevara Carazas, Fernando Jesús 21 March 2011 (has links)
No mercado mundial de geração e comercialização de energia elétrica, termos como Sustentabilidade, Responsabilidade Ambiental, Satisfação do Consumidor, Alta Disponibilidade e Redução de Custos direcionam os objetivos das empresas geradoras. Com a intenção de cumprir com estes objetivos, são investidas grandes quantidades de recursos para conseguir um desenvolvimento técnico-científico das diversas áreas da empresa, e de forma especial às de Operação e Manutenção (O&M), responsáveis diretas pela operação das instalações. Neste contexto, a filosofia da Manutenção Centrada em Confiabilidade (MCC) proporciona uma metodologia bem estruturada para a seleção de políticas de manutenção que permitem a redução de intervenções desnecessárias, dos custos relacionados a estas, e permite a operação com alta confiabilidade, produto da redução da probabilidade de ocorrência de falhas. Apesar destas vantagens, o MCC carece de um mecanismo que estime os riscos relacionados com uma determinada condição de operação, o que leva aos operadores a procurar estratégias de seleção de políticas de manutenção que complementem a filosofia do MCC. A análise de risco de operações industriais proporciona um mecanismo para a tomada de decisões estratégicas relacionadas à instalação de equipamentos de segurança e/ou mudanças nas políticas de manutenção, por meio da quantificação das probabilidades de ocorrência de falhas e dos custos relacionados às possíveis conseqüências produto da ocorrência de falhas. Este trabalho apresenta um método baseado nos conceitos de confiabilidade e análise de risco que auxilia a tomada de decisões na seleção de estratégias de operação que visem a alta disponibilidade das usinas de geração de energia elétrica, por meio da seleção de políticas de manutenção e/ou identificação da necessidade da instalação de novos equipamentos críticos. Desta forma, as decisões serão auxiliadas por um método de análise bem estruturado, que permite identificar os sistemas e componentes que em caso de ocorrência de falhas poderiam ocasionar conseqüências perigosas relacionadas à segurança, ao meio ambiente, à vida dos operadores, à integridade física das instalações e às atividades comerciais das empresas geradoras. O método é aplicado em uma usina termelétrica com potencia de cerca de 500MW. / In the global market of electricity generation, terms such as Sustainability, Environmental Responsibility, Customer Satisfaction, High Availability and Reduced Costs guide the actions of businesses as main goals in planning their activities. With the determination to meet these goals, companies invest large amounts of resources to achieve a technical-scientific development in the various areas of the company, especially in the Operation and Maintenance (O & M), responsible for direct operation of the facilities. In this context, the philosophy of Reliability Centered Maintenance (RCM) provides a well structured methodology for the selection of maintenance policies, which allow the reduction of maintenance unnecessary interventions, reducing costs related to these, and increasing system reliability due decreasing the probability of failure. Despite these advantages, RCM lacks a mechanism to estimate the risks associated with a given operating condition, which motivates operators to seek strategies for selecting maintenance policies that complement the RCM philosophy. Risk analysis of industrial operations provide a mechanism for making strategic decisions related to the installation of safety equipment and / or changes in maintenance policies, by quantifying the probability of failures and the costs related to the possible consequences of failures occurrence. This Doctoral thesis presents a method based on the concepts of reliability and risk analysis to aid decision making in the selection of operating strategies that address the high availability of electric power plants through the selection of maintenance policies and/or the identification of the need of installing new equipment. Thus, decisions will be aided by a well structured method of analysis helping, to identify systems and components that in case of failures could lead to very dangerous consequences related to safety, environment, operators\' life, integrity of facilities and commercial activities the company. The method is applied on the analysis of a 500 MW thermal power plant.
14

Hybrid Solar Gas-Turbine Power Plants : A Thermoeconomic Analysis

Spelling, James January 2013 (has links)
The provision of a sustainable energy supply is one of the most importantissues facing humanity at the current time, and solar thermal power hasestablished itself as one of the more viable sources of renewable energy. Thedispatchable nature of this technology makes it ideally suited to forming thebackbone of a future low-carbon electricity system.However, the cost of electricity from contemporary solar thermal power plantsremains high, despite several decades of development, and a step-change intechnology is needed to drive down costs. Solar gas-turbine power plants are apromising new alternative, allowing increased conversion efficiencies and asignificant reduction in water consumption. Hybrid operation is a furtherattractive feature of solar gas-turbine technology, facilitating control andensuring the power plant is available to meet demand whenever it occurs.Construction of the first generation of commercial hybrid solar gas-turbinepower plants is complicated by the lack of an established, standardised, powerplant configuration, which presents the designer with a large number ofchoices. To assist decision making, thermoeconomic studies have beenperformed on a variety of different power plant configurations, includingsimple- and combined-cycles as well as the addition of thermal energy storage.Multi-objective optimisation has been used to identify Pareto-optimal designsand highlight trade-offs between costs and emissions.Analysis of the simple-cycle hybrid solar gas-turbines revealed that, whileelectricity costs were kept low, the achievable reduction in carbon dioxideemissions is relatively small. Furthermore, an inherent trade-off between thedesign of high efficiency and high solar share hybrid power plants wasidentified. Even with the use of new optimised designs, the degree of solarintegration into the gas-turbine did not exceed 63% on an annual basis.In order to overcome the limitations of the simple-cycle power plants, twoimprovements were suggested: the integration of thermal energy storage, andthe use of combined-cycle configurations. Thermal energy storage allowed thedegree of solar operation to be extended, significantly decreasing carbondioxide emissions, and the addition of a bottoming-cycle reduced the electricitycosts. A combination of these two improvements provided the bestperformance, allowing a reduction in carbon dioxide emissions of up to 34%and a reduction in electricity costs of up to 22% compared to a combination ofconventional power generation technologies. / Hållbar energiförsörjning är för närvarande en av de viktigaste frågorna förmänskligheten. Koncentrerad solenergi är nu etablerad som en tillförlitlig källaav förnybar energi. Den reglerbara karaktären hos tekniken gör den specielltintressant för uppbyggnaden av ett framtida koldioxidsnålt elsystem.Kostnaden för elektricitet från nuvarande termiska solkraftverk är hög trottsflera decennier av utveckling. Ett genombrått på tekniknivå krävs för att drivaned kostnaderna. Sol-gasturbiner är ett av de mest lovande alternativen, somger en ökad verkningsgrad samtidigt som vattenkonsumtionen reducerasdrastiskt. Sol-gasturbintekniken gör det möjligt att blandköra solenergi ochandra bränslen för att möta efterfrågan vid alla tidpunkter, en attraktiv aspekt iförhållande till alternativa lösningar.Uppbyggnaden av första generationens kommersiella hybrida solgasturbinkraftverkförsvåras dock av bristen på etablerade och standardiseradekraftverkskonfigurationer. Dessa ger planeraren ett stort antal valmöjlighetersom underlag för beslutsfattande. Termoekonomiska studier har genomförtsför ett flertal olika kraftverkskonfigurationer, däribland kraftverk med enkelcykel, kombikraftverk samt möjligheten att utnyttja termisk energilagring.Pareto-optimala konfigurationer har identifierats med hjälp av multiobjektsoptimeringför att belysa balansen mellan kostnader och utsläpp.Analysen av det enkla hybrida sol-gasturbinkraftverket visade attelektricitetskostnaden hållits på en låg nivå, men att den möjliga minskningen avkoldioxidutsläpp är relativt liten. Dessutom identifierades en inre balans mellanatt bibehålla en hög verkningsgrad hos konfigurationen och en hög andelsolenergi i produktionen. Andelen av solenergi i gasturbinen överskred aldrig63% på årlig bas, även med optimerade kraftverkskonfigurationer.Två förbättringar föreslås för att övervinna begränsningarna hos kraftverk medenkel cykel: integration av termisk energilagring samt nyttjande avkombikraftverkskonfigurationer. Termisk energilagring tillåter en ökad andelsolenergi i driften och reducerar koldioxidutsläppen drastiskt, medan denytterligare cykeln hos kombikraftverket reducerar elektricitetskostnaden.Kombinationen av dessa förbättringar ger den bästa prestandan, med enreduktion av koldioxidutsläppen på upp till 34% och reducerade elektricitetskostnaderpå upp till 22% i jämförelse med andra kombinationer avkonventionella kraftverkskonfigurationer. / <p>QC 20130503</p>
15

Evaluation of the released thermal power in wood pellets

Zander, Carin January 2006 (has links)
This Degree Project has been done at Växjö University, department of bioenergy technology and discusses the released thermal power in wood pellets. The purpose of the project is to investigate if two new types of wood biofuels (pellets) are more or less reactive than the pellets previously investigated at Växjö University. To measure the released thermal power, an isothermal calorimeter with eight channels has been used. To see how the microbial activity is influenced, the pellets have been stored under various conditions with focus on temperature and metal.
16

Study on Architecture-Oriented Thermal power station Alteration Affairs Management Model

Huang, Rong-Yu 03 January 2012 (has links)
Electricity construction is required for a country¡¦s fundamental economic development. It provides the needed power and plays an important role in modern society. In order to develop sufficient electricity, Taiwan government has launched a construction project in the whole country starting from the year of 2004. The thermal power station is the major source of electricity in Taiwan and will take long time to construct. Based on the guidelines of Executive Yuan¡¥s Public Construction Commission, the construction shall focus on material management system; coordinate, monitor and examine the project; review by routine and check on site; integrate technology and experts from the production field to raise the execution effect and process quality. Alteration of thermal power station consists of generating set and supportive equipment. The construction methodology will determine if the construction can or not be completed on time. With reference by managerial and operational scopes of some enterprises, this thesis sets up Architecture-Oriented Thermal Power Station Alteration Affairs Management Model, abbreviated as AOTPSAAMM, to describe the whole picture for the thermal power station alteration project and further to achieve the aims on controlling schedule and raising knowledge management. AOTPSAAMM contains the architecture of thermal power station alteration construction. It not only describes the coalescence of organizational structure and organizational behavior in enterprise value chains, but also integrates with technology application systems. With duplicating and expanding capabilities, AOTPSAAMM will easily apply to other generating electricity system and create contemporary enterprise excellences.
17

Design Of A High Temperature Erosion Apparatus For Testing Of Boiler Tubes

Ergun, Huseyin 01 October 2010 (has links) (PDF)
In this thesis an apparatus is designed which enables the testing of thermal power plant boiler tubes against erosion. The apparatus makes use of a tube sample directly cut from the boiler tubes and simulates conditions similar to those prevailing in boilers in lignite fired power plants. The apparatus is composed of three components / a furnace for heating the sample, a loading system which allows application of tensile stresses while allowing the rotation of the sample, and a particle blower that delivers abrasive particles to the surface of the sample. The abrasive material used in the test is mixture of oxides, 90% of which is Al2O3 and the average particle size is approximately 300 &micro / m. The unit as designed would allow testing of boiler tubes up to a temperature of 650 C, and particle velocity of up to 50 m/s. The apparatus as tested at room temperatures for four identical samples have yielded very similar erosion values based on measurement of weight loss. At elevated temperature, erosion could be measured by a thickness loss since the oxidation that occurs complicates the erosion measurement. Two economizer material / P235GH and 16Mo3 were tested at 500oC with particle velocity of 10 m/s. The testing has shown that 16Mo3 has better performance than P235GH, the erosion rate differing by 20 percent.
18

Simulations Of A Large Scale Solar Thermal Power Plant In Turkey Using Concentrating Parabolic Trough Collectors

Usta, Yasemin 01 December 2010 (has links) (PDF)
In this study, the theoretical performance of a concentrating solar thermal electric system (CSTES) using a field of parabolic trough collectors (PTC) is investigated. The commercial software TRNSYS and the Solar Thermal Electric Components (STEC) library are used to model the overall system design and for simulations. The model was constructed using data from the literature for an existing 30-MW solar electric generating system (SEGS VI) using PTC&rsquo / s in Kramer Junction, California. The CSTES consists of a PTC loop that drives a Rankine cycle with superheat and reheat, 2-stage high and 5-stage low pressure turbines, 5-feedwater heaters and a dearator. As a first approximation, the model did not include significant storage or back-up heating. The model&rsquo / s predictions were benchmarked against published data for the system in California for a summer day. Good agreement between the model&rsquo / s predictions and published data were found, with errors usually less than 10%. Annual simulations were run using weather data for both California and Antalya, Turkey. The monthly outputs for the system in California and Antalya are compared both in terms of absolute monthly outputs and in terms of ratios of minimum to maximum monthly outputs. The system in Antalya is found to produce30 % less energy annually than the system in California. The ratio of the minimum (December) to maximum (July) monthly energy produced in Antalya is 0.04.
19

Thermodynamic and Engineering Analysis of Applying Gas Turbine Inlet Air Cooling Systems for Combined-Cycle Power Plant

Chiang, Chen-Yu 08 July 2001 (has links)
Abstract In recent years, domestic energy policy has continuously changed, especially, after a liberalization of electric power market opened, resulting into the power industry proprietor expected to has a stable electric power supply systems, high power generation, high thermal efficiency and low heat rate. They will consistently devise a way to propose a strategy of improved or enhanced in the light of a competitive footstone for electric force market. About 90% worldwide and 65% domestic electricity are generated by the thermal power plants, where the energy source is obtained from burning the fossil fuels. Therefore, Increasing the power generation capacity of thermal power plants will substantially raise to the percent reserve margin of to be smaller than 12% over the years. In Taiwan, the ambient temperature is always higher than 30oC at summer. When gas turbine has operated during peak, gave rise to deteriorate its power generation capability and often actually generated power lower 10% than based on a design condition of ISO 15oC. This study adopts a way which is not same as conventional method increased power generation capability of the thermal power plants. In other word, reducing the inlet air temperature to gas turbine, it will increase the air flow mass rate and the generated-power capacity. By means of EPRI Gate Cycle Software constructing a typical combined-cycle power plant, at the same time, to simulate and to search out an effective operating control strategy for the power plant with GTIAC. Furthermore, applying the electric chiller and the absorption chiller to combined-cycle power plant as an inlet air cooling system use thermodynamic and engineering analysis to discuss an extent of energy utilizing, the valuability of energy application, to access the economic effect of investing equipment to acquire an optimal balance point. Selecting the inlet air temperature 15oC,10oC and comparing the thermal performance of electric chiller with that of absorption chiller. Then, proposing a feasible suggestion to treat as an important reference criteration of improving present power GENSET and planning to install a thermal power plant for the electric power proprietor.
20

Evaluation of the released thermal power in wood pellets

Zander, Carin January 2006 (has links)
<p>This Degree Project has been done at Växjö University, department of bioenergy technology and discusses the released thermal power in wood pellets. The purpose of the project is to investigate if two new types of wood biofuels (pellets) are more or less reactive than the pellets previously investigated at Växjö University. To measure the released thermal power, an isothermal calorimeter with eight channels has been used. To see how the microbial activity is influenced, the pellets have been stored under various conditions with focus on temperature and metal.</p>

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