Dissertations / Theses: 'Steam power plants'

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Yunt, Mehmet 1975. "Steam temperature regulation in fossil power plants." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/89876.

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Baker, Jeffery K. Terhune Jeffery S. "The effects of strobe light and sound behavioral deterrent systems on impingement of aquatic organisms at Plant Barry, Alabama." Auburn, Ala, 2008. http://repo.lib.auburn.edu/EtdRoot/2008/FALL/Fisheries_and_Allied_Aquacultures/Thesis/Baker_Jeffery_24.pdf.

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Wakeley, Guy Richard. "The optimisation of steam turbine design." Thesis, University of Newcastle Upon Tyne, 1997. http://hdl.handle.net/10443/2041.

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The world market-place for steam turbine products is becoming increasingly competitive, and manufacturers must routinely produce designs which are extensively optimised whilst working within demanding tender and contract lead-times. The objective of the research work has been to develop a methodology whereby established turbomachinery analysis methods can be integrated within a framework of optimising algorithms. A rule-base, numerical optimisation, fuzzy logic, and genetic algorithms are used to optimise bladepath configurations, with particular emphasis on the minimisation of life-cycle operating costs. Significantly, automation of the design process is increased, design lead-times can be reduced, and performance improvements are predicted. The optimisation procedure relies on a sequential approach, with much emphasis placed on the iterative running of simple design codes. Simplified design methods are often reliant on correlated loss data to predict turbine performance, and in some cases this data is inaccurate or incomplete. An example of this is in the design of partially-admitted control stages, where little published data is available. It is suggested that CFD methods can, in some cases, be applied to derive new performance correlations or re-assess the validity of existing models. The application of an unsteady CFD solver to typical control stage geometries is presented in detail, and the approach is extended to include the development of a new control stage optimisation method.

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Saalfeld, David Thomas Bayne David Roberge. "Variables influencing fish impingement at five Alabama Power steam plants." Auburn, Ala., 2006. http://repo.lib.auburn.edu/2006%20Spring/master's/SAALFELD_DAVID_51.pdf.

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Melnyk, Glenn J. "Mechanisms for automated toolhead changing in nuclear steam generator robotics." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-06302009-040338/.

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Honing, Werner. "Steam flow distribution in air-cooled condenser for power plant application." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/2540.

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Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2009.
ENGLISH ABSTRACT: Air-cooled steam condensers are used in arid regions where adequate cooling water is not available or very expensive. In this thesis the effect of steam-side and air-side effects on the condenser performance, steam distribution and critical dephlegmator length is investigated for air-cooled steam condensers as found in power plants. Solutions are found so that no backflow is present in the condenser. Both single and two-row condensers are investigated. The tube inlet loss coefficients have the largest impact on the critical dephlegmator tube length in both the single and two-row condensers. The critical dephlegmator tube lengths were determined for different dividing header inlet geometries and it was found that a step at the inlet to the dividing header resulted in the shortest tubes. Different ambient conditions were found to affect the inlet steam temperature, the steam flow distribution, heat rejection distribution and the critical dephlegmator length for the single and two-row condensers. There were differences in the steam mass flow distributions for the single and two-row condensers with opposite trends being present in parts of the condenser. The single-row condenser’s critical dephlegmator tube lengths were shorter than those of the two-row condenser for the same ambient conditions. Areas of potential backflow change with different ambient conditions and also differ between a single and two-row condenser. The two-row condenser always have an area of potential backflow for the first row at the first condenser fan unit.
AFRIKAANSE OPSOMMING: Droë lug-verkoelde stoom kondensors word gebruik in droë gebiede waar genoegsame verkoelingswater nie beskikbaar is nie of baie duur is. In hierdie tesis word die effek van stoomkant en lugkant effekte op die vermoë van die kondensor, die stoomvloeiverdeling en kritiese deflegmator lengte ondersoek vir lug-verkoelde stoom kondensors soos gevind in kragstasies. Dit word opgelos sodat daar geen terugvloei in enige van die buise is nie. ŉ Enkel- en dubbelry kondensor word ondersoek. Die inlaatverlieskoëffisiënte van die buise het die grootste impak op die lengte van die kritiese deflegmator buise in beide die enkel- en dubbelry kondensors. Die kritiese deflegmator buis lengtes is bereken vir verskillende verdeelingspyp inlaat geometrië en dit is gevind dat ŉ trap by die inlaat van die verdeelingspyp die kortste buise lewer. Dit is gesien dat verskillende omgewingskondisies die inlaat stoom temperatuur, die stoomvloeiverdeling, die warmteoordrag verdeling en die kritiese lengte van die deflegmator buise vir die enkel- en dubbelry kondensor. Daar was verskille tussen die stoomvloeiverdelings vir die enkel- en dubbelry met teenoorgestelde neigings in dele van die kondensor. Die kritiese deflegmator buis lengte vir die enkelry kondensor was korter as die vir die dubbelry kondensor vir dieselfde omgewingskondisies. Die areas in die kondensor waar terugvloei moontlik kan plaasvind in die kondensor verander met ongewingskondisies en verskil vir die enkel- en dubbelry kondensers. Die dubbelry kondensor het altyd ŉ area van moontlike terugvloei vir die eerste buisry by die eerste kondensor waaiereenheid.

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Knight, Amelia Cassidy Terhune Jeffery S. "General fish health assessment and age evaluation of impinged fish at steam generating power plants." Auburn, Ala, 2008. http://repo.lib.auburn.edu/EtdRoot/2008/FALL/Fisheries_and_Allied_Aquacultures/Thesis/Knight_Amelia_50.pdf.

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Edwards, Jacob N. "Thermal energy storage for nuclear power applications." Thesis, Kansas State University, 2017. http://hdl.handle.net/2097/36238.

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Master of Science
Department of Mechanical and Nuclear Engineering
Hitesh Bindra
Storing excess thermal energy in a storage media that can later be extracted during peak-load times is one of the better economical options for nuclear power in future. Thermal energy storage integration with light water-cooled and advanced nuclear power plants is analyzed to assess technical feasibility of different storage media options. Various choices are considered in this study; molten salts, synthetic heat transfer fluids, and packed beds of solid rocks or ceramics. In-depth quantitative assessment of these integration possibilities are then analyzed using exergy analysis and energy density models. The exergy efficiency of thermal energy storage systems is quantified based on second law thermodynamics. The packed bed of solid rocks is identified as one of the only options which can be integrated with upcoming small modular reactors. Directly storing thermal energy from saturated steam into packed bed of rocks is a very complex physical process due to phase transformation, two phase flow in irregular geometries and percolating irregular condensate flow. In order to examine the integrated physical aspects of this process, the energy transport during direct steam injection and condensation in the dry cold randomly packed bed of spherical alumina particles was experimentally and theoretically studied. This experimental setup ensures controlled condensation process without introducing significant changes in the thermal state or material characteristics of heat sink. Steam fronts at different flow rates were introduced in a cylindrical packed bed and thermal response of the media was observed. The governing heat transfer modes in the media are completely dependent upon the rate of steam injection into the system. A distinct differentiation between the effects of heat conduction and advection in the bed were observed with slower steam injection rates. A phenomenological semi-analytical model is developed for predicting quantitative thermal behavior of the packed bed and understanding physics. The semi-analytical model results are compared with the experimental data for the validation purposes. The steam condensation process in packed beds is very stable under all circumstances and there is no effect of flow fluctuations on thermal stratification in packed beds. With these experimental and analytical studies, it can be concluded that packed beds have potential for thermal storage applications with steam as heat transfer fluid. The stable stratification and condensation process in packed beds led to design of a novel passive safety heat removal system for advanced boiling water reactors.

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Lucquiaud, Mathieu. "Steam cycle options for capture-ready power plants, retrofits and flexible operation with post-combustion CO₂ capture." Thesis, Imperial College London, 2010. http://hdl.handle.net/10044/1/5942.

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The energy penalty for post‐combustion carbon dioxide capture from fossil‐fired power plants can be greatly reduced ‐ independently of the intrinsic heat of regeneration of the solvent used ‐ by effective thermodynamic integration with the power cycle. Yet expected changes in electricity generation mix and the current immaturity of post‐combustion capture technology are likely to make effective thermodynamic integration throughout the operating life of such plants a challenging objective to achieve because of a requirement for extensive part‐load operation and also for matching to future technology improvements. Most previous published studies have, however, focused on base‐load operation of the power cycle and the carbon dioxide capture plant and with the assumption of a fixed technology. For carbon dioxide capture‐ready plants the characteristics of the capture plant are also not known when the plant is designed. The plant must operate initially without capture at a similar efficiency to ‘standard’ plants to be competitive. Capture‐ready plants then also need to be able to be retrofitted with unknown improved solvents and to be capable of integration with a range of future solvents. This study shows that future upgradability for post‐combustion capture systems can be facilitated by appropriate steam turbine and steam cycle designs. In addition fossil‐fired power plants with postcombustion capture may need to be able to operate throughout their load range with the capture unit by‐passed, or with intermediate solvent storage to avoid the additional emissions occurring when the absorption column is by‐passed. Steam cycles with flexible steam turbines can be adequately designed to accommodate for part‐load operation with these novel operating conditions and with rapid ramp rates. Several approaches for effective capture‐ready pulverised coal and natural gas plants are also described. These achieve identical performance before retrofit to a conventional plant with the same steam conditions, but have the potential to perform well after capture retrofit with a wide range of solvents, at the expense of only a small efficiency penalty compared to hypothetical plants built with perfect foreknowledge of the solvent energy requirements. For existing plants that were not made capture‐ready, and provided sufficient space is available and other physical limits are not too constraining, ways to achieve effective thermodynamic integration are also discussed.

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Oexmann, Jochen [Verfasser]. "Post-combustion CO2 capture : energetic evaluation of chemical absorption processes in coal-fired steam power plants / Jochen Oexmann." Hamburg : Universitätsbibliothek der TU Hamburg-Harburg, 2011. http://d-nb.info/1012653196/34.

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Ferreira, Elzimar Tadeu de Freitas. "Análise de centrais termelétricas para a geração distribuída e centralizada /." Guaratinguetá, 2016. http://hdl.handle.net/11449/143089.

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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

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Smit, Leslie van Zyl. "Inlet manifold tests and performance evaluation of dephlegmators in air-cooled steam condensers." Thesis, Stellenbosch : Stellenbosch University, 2000. http://hdl.handle.net/10019.1/51800.

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Thesis (MScEng)--University of Stellenbosch, 2000.
ENGLISH ABSTRACT: Measurements on air-cooled reflux steam condensers or dephlegmators at different power plants have shown that sections of these units do not transfer heat effectively over a range of operating conditions. The ineffective sections may be due to flooding in the finned tubes although entrainment of condensate in certain steam inlet manifolds is usually the main reason for the poor performance. In this dissertation factors that limit effective dephlegmator operation are discussed and the influence of two inlet manifold designs on dephlegmator operation is investigated. Laboratory experiments are conducted to show under which conditions liquid entrainment occurs and to visualize the flow distribution within the respective manifolds. An alternative, essentially horizontal arrangement of the dephlegmator is proposed. In order to evaluate the performance of such a system, the heat transfer and pressure drop on the steam-side is determined experimentally in an air-cooled finned tube. No flooding was observed during tests conducted at zero and negative tube angles to the horizontal.
AFRIKAANSE OPSOMMING: Toetse op lugverkoelde stoom terugvloeikondensors, of deflegmators, by verskeie kragstasies het getoon dat sekere dele van hierdie eenhede onder verskeie werkstoestande nie warmte effektief oordra nie. Hierdie oneffektiewe dele kan deur vloeding van die vinbuise veroorsaak word alhoewel die meesleur van kondensaat in sekere stoom inlaatspruitstukke gewoonlik die hoof oorsaak is. In hierdie dissertasie word faktore wat effektiewe deflegmator werksverrigting beinvloed bespreek en die invloed van twee inlaatspruitstukontwerpe op deflegmator werksverrigting ondersoek. Eksperimente is in 'n laboratorium uitgevoer om aan te toon onder watter werkstoestande vloeistof samesleping voorkom en om vloeiverdeling binne die onderskeie inlaatspruitstukke te visualiseer. 'n Altematiewe, wesenlike horisontale deflegmator opstelling word voorgestel. Die werksverrigting van hierdie voorstelling is ondersoek deur die warmteoordrag en stoorn-kant drukval eksperimenteel te bepaal in 'n lugverkoelde vinbuis. Geen vloeding is opgemerk vir toetsgevalle waar klein negatiewe of zero hoeke tot die horisontaal ondersoek is nie.

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Van, der Spuy Sybrand Johannes. "Perimeter fan performance in forced draught air-cooled steam condensers." Thesis, Stellenbosch : Stellenbosch University, 2011. http://hdl.handle.net/10019.1/17858.

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Thesis (PhD)--Stellenbosch University, 2011.
ENGLISH ABSTRACT: Axial flow fan arrays form part of air-cooled steam condensers in direct drycooled power plants. This dissertation investigates the performance of axial flow fans when located at the perimeter of a fan array. The perimeter (or edge) fans may experience a reduction in air flow through the fan due to the prevalence of distorted inlet conditions upstream of the fan. The reduction in air flow leads to a reduction in the heat transfer capability of the steam condenser and a consequent reduction in the electricity output of the power plant. Due to the physical size of an air-cooled condenser, full-scale experiments are often impractical and computational fluid dynamics (CFD) is used to model its performance under various conditions. To limit the size of the CFD model the axial flow fans in the CFD analysis are represented by means of simplified methods. Three different simplified methods are presented and applied to a CFD model of a single axial flow fan, namely the pressure jump method (PJM), actuator disc method (ADM) and extended actuator disc method (EADM). The results are compared to experimental values. The comparison highlights the limitations of the models: The ADM fails to model fan performance correctly at low flow rates, while the PJM ignores the variation in fan blade properties at different locations within the fan rotor. The EADM is presented as an improvement on both the other two models. A multiple fan test facility is constructed, consisting of three 630 mm diameter fans extracting air from a common inlet chamber. The inlet chamber is constructed in such a way that one of the three fans act as the perimeter (edge) fan. The floor of the inlet chamber can be adjusted to increase or reduce the inlet flow distortion experienced by the edge fan. Six different fan configurations are tested in the position of the edge fan and an empirical method is derived by which the volumetric effectiveness of an edge fan can be predicted. The experimental results are compared to CFD results for the same facility using the three different simplified simulation methods investigated previously. Particle image velocimetry (PIV) measurements are also performed upstream of the edge fan and the velocity profiles at the inlet of the fan are compared to the profiles obtained numerically. The comparisons show that the EADM predicts the performance of the edge fan more accurately than the ADM en PJM. The effect of adding a walkway and removing the bell mouth upstream of the edge fan was investigated using the EADM. The results are used to show the location of the loss mechanisms upstream of the edge fan. The addition of a walkway moves the location of the pressure loss away from the edge fan bell mouth towards the edge of the walkway. Consequently the distortion directly upstream of the edge fan is reduced and its volumetric effectiveness increased. The effect of removing the edge fan’s bell mouth is similar to the effect of adding a walkway upstream of the edge fan.
AFRIKAANSE OPSOMMING: Aksiaalwaaiermatrikse vorm deel van lugverkoelde kondensors in direk droëverkoelde kragstasies. Hierdie verhandeling ondersoek die werkverrigting van aksiaalwaaiers wat geleë is op die rand van ‘n groot waaiermatriks. Die randwaaiers kan ’n vermindering in deurvloei ondervind as gevolg van versteurde inlaattoestande stroom-op vanaf die waaier. Die vermindering in lugvloei lei tot ’n vermindering in die warmetoordagvermoë van die stoomkondensor en ’n gepaardgaande afname in die elektrisiteitslewering van die kragstasie. As gevolg van die fisiese grootte van die lugverkoelde kondensor is volskaalse eksperimente gewoonlik onprakties en word berekeningsvloeimeganika (BVM) gebruik om die werking van die aanleg onder verskeie toestande te modelleer. Ten einde die grootte van die BVM model te beperk, word die aksiaalwaaiers in so ‘n BVM analiese voorgestel met behulp van vereenvoudigde metodes. Drie verskillende vereenvoudigde metodes word aangebied en toegepas op ‘n BVM model van ‘n enkelwaaier, naamlik die druksprongmetode, die aksieskyfmetode en die verlengde aksieskyfmetode. Die resultate word vergelyk met eksperimentele waardes. Die vergelyking benadruk die beperkings van die modelle: Die aksieskyfmetode kan nie die werking van die waaier akkuraat voorspel by lae vloeie nie en die druksprongmetode ignoreer die variasie in lemeienskappe op verskillende liggings binne-in die waaierrotor. Die verlengde aksieskyfmetode word voorgestel as ‘n verbetering op die ander twee metodes. ‘n Veelvuldige waaiertoetsfasiliteit is saamgestel, bestaande uit drie 630 mm deursnee waaiers wat lug uit ’n gemeenskaplike inlaatkamer suig. Die inlaatkamer is so saamgestel dat een van die waaiers in die fasiliteit ‘n randwaaier verteenwoordig. Die vloerhoogte van die inlaatkamer kan aangepas word om die inlaatversteuring wat deur die raandwaaier ondervind word te vermeerder of te verminder. Ses verskillende waaierkonfigurasies is getoets in die randwaaierposisie. ‘n Empiriese metode waarmee die volumetriese effektiwiteit van ‘n randwaaier voorspel kan word is afgelei. Die eksperimentele resultate word vergelyk met ooreenstemmende BVM resultate vir dieselfde fasiliteit deur gebruik te maak van die drie verskillende vereenvoudigde metodes wat vroeër ondersoek is. Partikelbeeld snelheidsmetings word ook stroom-op vanaf die randwaaier uitgevoer en die snelheidsprofiele by die inlaat van die waaier word vergelyk met profiele wat numeries bereken word. Die vergelykings wys dat die verlengde aksieskyfmetode die werkverrigting van ’n aksiaalwaaier meer akkuraat voorspel as die aksieskyf- of druksprongmetodes. Die effek van die installering van ‘n loopvlak en die verwydering van die randwaaier se inlaatmondstuk word ondersoek met behulp van BVM deur gebruik te maak van die verlengde aksieskyfmetode. Die resultate word spesifiek gebruik om die ligging van die verliesmeganismes stroom-op vanaf die randwaaier aan te dui. Die resultate wys dat die installering van ‘n loopvlak die ligging van die drukverlies wegneem vanaf die rand van die waaierinlaat na die rand van die loopvlak. Dit verminder die inlaatversteuring stroom-op vanaf die randwaaier en die volumetriese effektiwiteit word verhoog. Die verwydering van die randwaaier se inlaatmondstuk het ‘n soortgelyke effek as die installering van ‘n loopvlak stroom-op vanaf die randwaaier.

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Santos, Caio Felipe de Paula. "Análise termoeconômica e eficiência ecológica de uma termoelétrica com absorção química de CO2 /." Guaratinguetá, 2016. http://hdl.handle.net/11449/138083.

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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

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Boulesteix, Claire. "Synthesis, environmental degradation and repairability of slurry aluminium coatings elaborated on steels employed in power plants." Thesis, La Rochelle, 2017. http://www.theses.fr/2017LAROS022/document.

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L’augmentation des températures et des pressions de travail des centrales de production d’énergie représente un enjeu considérable en termes de réduction d’émission de polluants et d’augmentation d’efficacité énergétique. Pour cela, des matériaux plus performants par rapport à ceux employés actuellement doivent être utilisés afin de résister aux environnements sévères (hautes températures, 100% vapeur d’eau, pression…). Malgré les bonnes propriétés mécaniques de bon nombre d’aciers, l’application d’un revêtement protecteur capable de former une couche d’oxyde dense, protectrice et stable à haute température, est essentielle. Ainsi, dans le cadre du projet Européen FP-7 « POEMA », nous nous sommes intéressés aux mécanismes de formation de revêtements de diffusion d’aluminium sur des aciers ferrito-martensitiques et austénitiques fréquemment employés dans ce type de centrales. Des études sur la colmatation des fissures éventuellement parues durant l’aluminisation des aciers ont été également réalisées. Les mécanismes de dégradation des revêtements B2-(Fe (Ni))Al ont ensuite été étudiés sous 100% vapeur d’eau et sous air à 650 et 700°C jusqu’à 10000 heures et sous différentes pressions (1 et 300 bar). Nous avons démontré que la pré-oxydation induite lors de l’élaboration du revêtement permet de faire croître une fine couche protectrice de α-Al2O3 qui se développe au cours de l’oxydation. Cependant, les longues expositions sous fortes pressions de vapeur promeuvent la diffusion cationique de Fe, ceci donnant lieu à des petits nodules surfaciques d’oxyde. Enfin, les mécanismes de dissolution des revêtements avec un acide dilué ont été étudiés afin de montrer la possibilité de décaper puis de réaluminiser les matériaux initialement revêtus
Higher energy efficiencies can be achieved by the increase of temperatures and pressures in power plant, thus allowing the reduction of the polluting emissions. Therefore, more efficient materials, compared to those currently employed, have to be used in order to resist to harsh environmental conditions (high temperatures, steam, pressure…). Despite of the good mechanical properties of many steels, the elaboration of a protective coating able to form a dense, protective and stable oxide layer at high temperature, is necessary. Thus, in the framework of the “POEMA” European project, the mechanisms of the formation of aluminium diffusion coatings were studied on ferritic-martensitic and austenitic stainless steels that are currently employed in power plants. The sealing of cracks eventually created during the aluminisation of steels was also studied. The degradation mechanisms of the B2-(Fe (Ni))Al coatings were then studied in steam and in air at 650 and 700°C up to 10000 hours and under different pressures (1 and 300 bar). We have demonstrated that the pre-oxidation induced during the elaboration of coatings grew a thin protective oxide scale composed of α-Al2O3 which developed further upon oxidation. Nevertheless, the long exposures under high steam pressures promoted the cationic diffusion of Fe, thus allowing the formation of small surface oxide nodules. Finally, the dissolution mechanisms of coatings with a diluted acid have been studied in order to demonstrate the possibility of strip and realuminise the materials initially coated

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Joubert, Retief. "Influence of geometric and environmental parameters on air-cooled steam condenser performance." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/4153.

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Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2010.
ENGLISH ABSTRACT: Air-cooled steam condensers (ACSCs) are used in the power generation industry to directly condense turbine exhaust steam in areas where cooling water is expensive or unavailable. Large axial flow fans force ambient air through A-frame heat exchanger bundles made up of a number of rows of finned tubes through which the steam is ducted and consequently condensed during the heat transfer process to the air. The heat rejection rate or performance of an ACSC is proportional to the air mass flow rate, determined by fan volumetric performance, and the temperature difference between the finned tubes and the air. The air flow through a 30 fan ACSC (termed the generic ACSC) operating under windy conditions is solved using the commercial computational fluid dynamics (CFD) code FLUENT and the required data is extracted from the solution to calculate performance trends. It is found that fan performance is reduced due to a combination of factors. The first is additional upstream flow losses caused by separated flow occurring primarily at the leading edge of the ACSC and secondarily at the fan bellmouth inlets. The second factor leading to reduced fan performance is the presence of distorted flow conditions at the fan inlets. Hot plume air recirculation is responsible for decreased ACSC thermal performance due to increased fan inlet air temperatures. It is found that reduced fan performance is the greater contributor to reduced ACSC performance. The performance effects of varying two geometrical parameters of the generic ACSC, namely the fan platform height and the windwall height, are investigated under windy conditions. It is found that each parameter is linked to a specific mechanism of performance reduction with the fan platform height affecting fan performance and the windwall height affecting recirculation. The respective platform and windwall heights specified for the generic ACSC are found to provide acceptable performance results. To mitigate wind induced performance reductions a number of modification and additions to the ACSC are investigated. These primarily aim at improving fan performance and included the addition of walkways or skirts, the addition of wind screens beneath the fan platform, removing the bellmouth fan inlets, using different types of fans and increasing fan power. The addition of a periphery walkway and windscreens is considered to be the most practical methods of improving ACSC performance under windy conditions. The generic ACSC is modified to include both modifications and under high wind conditions the performance is found to increase measurably. The modifications also resulted in the ACSC performance being less sensitive to wind direction effects.
AFRIKAANSE OPSOMMING: Lugverkoelde kondensators word in die kragopwekkings industrie gebruik om turbine uitlaatstoom te kondenseer, veral in gebiede waar verkoelingwater duur of onbeskikbaar is. Aksiaalvloei-waaiers forseer omgewingslug deur A-raam warmteuitruiler bondels wat bestaan uit verskeie rye vinbuise. Die uitlaatstoom vloei in die vinbuise en kondenseer as gevolg van die warmteoordrag na die lug. Die warmteoordragkapasiteit van die lugverkoelde stoom kondensator is eweredig aan die massavloei-tempo van die lug, wat bepaal word deur die waaierwerkverigting, en die temperatuur verskil tussen die vinbuise en die lug. Die lugvloei deur 'n 30 waaier lugverkoelde stoom kondensator (genoem die generiese lugverkoelde stoom kondensator) onderworpe aan winderige toestande word opgelos deur die gebruik van die kommersiële vloeidinamika-pakket, FLUENT. Die nodige data is onttrek uit die oplossing en werkverrigting neigings is bereken. Dit is gevind dat waaierwerkverigting verminder as gevolg van 'n kombinasie van faktore. Die eerste is bykomende vloeiverliese wat veroorsaak word deur vloeiwegbreking wat plaasvind primêr by die voorste rand van die lugverkoelde stoom kondensator asook by die klokvormige waaier-inlate. 'n Tweede faktor wat lei tot vermindere waaierwerkverigting is die teenwoordigheid van lugvloeiversteurings by die waaier-inlate. Hersirkulering van warm pluim lug is ook verantwoordelik vir verminderde lugverkoelde stoom kondensator werkverrigting. Daar word bevind dat die vermindering in waaierwerkverrigting die grootste bydraende faktor tot vermindere lugverkoelde stoom kondensator werkverrigting is. Die effek van verandering van twee geometriese lugverkoelde stoom kondensator parameters, naamlik die waaierplatformhoogte en die windwandhoogte is ondersoek onder winderige toestande. Daar word bevind dat elk van die parameters gekoppel is aan 'n spesifieke meganisme van vermindere lugverkoelde stoom kondensator verrigting: Die waaierplatformhoogte beïnvloed waaierverrigting terwyl die windwandhoogte hersirkulering beinvloed. Daar word ook bevind dat die onderskeie waaierplatform- and windwandhoogtes van die generiese lugverkoelde stoom kondensator, van so 'n aard is dat dit aanvaarbare werkverrigting tot gevolg het. Om verlaging in werksverrigting in winderige toestande te verminder is verskeie modifikasies en byvoegings tot die lugverkoelde stoom kondensator ondersoek wat primêr gemik is op verbetering in waaierwerkverigting. Die ondersoek dek die byvoeging van 'n loopvlak, die byvoeging van windskerms onder die waaierplatform, verwydering van die klokvormige waaier-inlate, die gebruik van verskillende waaiers en die verhoging van waaierdrywing. Daar was besluit dat die byvoeging van 'n loopvlak rondom die rand van die lugverkoelde stoom kondensator en die byvoeging van windskerms die mees praktiese manier was om die lugverkoelde stoom kondensator verigting te verbeter. Die generiese lugverkoelde stoom kondensator was aangepas om beide veranderings in te sluit en meetbare verbetering in werkrigting was verkry. Die veranderings het ook meegebring dat die lugverkoelde stoom kondensator minder sensitief is vir windrigting effekte.

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17

HIPOLITO, FABIO C. "Avaliação das metodologias de análise de sistemas de tubulações de vapor sujeitas a carregamentos do tipo Steam Hammer." reponame:Repositório Institucional do IPEN, 2016. http://repositorio.ipen.br:8080/xmlui/handle/123456789/26938.

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Carregamentos transientes termo hidráulicos do tipo Steam Hammer são eventos comuns em sistemas de tubulações de vapor com grandes potenciais de catástrofes em plantas de geração de energia. Uma vez iniciado o evento, ondas de pressões são geradas com amplitudes, geralmente, de grande magnitude ocasionando altas pressões no sistema, ruídos, deformações, fadiga, com possibilidade de danos materiais e econômicos e em casos extremos fatalidades. Os procedimentos da indústria para análise deste tipo de sistema consistem realização de análises estáticas equivalentes ou análise de espectro de resposta com carregamentos caracterizados por meio de métodos analíticos baseados em hipóteses simplificadoras do fluido e fluxo. Neste trabalho é proposta a analise de sistema de tubulações por meio do método de integração numérica com superposição modal e carregamento caracterizado por método numérico com base no método das características. Comparações foram efetuadas entre os resultados obtidos pela metodologia proposta e os procedimentos da indústria, demonstrando que, dado ao alto grau de conservadorismo, os procedimentos da indústria acarretam em superdimensionamento de estruturas e tubulações ocasionando custos adicionais de projeto, sendo a otimização do projeto obtida aplicando-se a metodologia proposta no trabalho.
Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP

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18

Arsalis, Alexandros. "Thermoeconomic Modeling and Parametric Study of Hybrid Solid Oxide Fuel Cell – Gas Turbine – Steam Turbine Power Plants Ranging from 1.5 MWe to 10 MWe." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/31005.

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Detailed thermodynamic, kinetic, geometric, and cost models are developed, implemented, and validated for the synthesis/design and operational analysis of hybrid solid oxide fuel cell (SOFC) – gas turbine (GT) – steam turbine (ST) systems ranging in size from 1.5 MWe to 10 MWe. The fuel cell model used in this thesis is based on a tubular Siemens-Westinghouse-type SOFC, which is integrated with a gas turbine and a heat recovery steam generator (HRSG) integrated in turn with a steam turbine cycle. The SOFC/GT subsystem is based on previous work done by Francesco Calise during his doctoral research (Calise, 2005). In that work, a HRSG is not used. Instead, the gas turbine exhaust is used by a number of heat exchangers to preheat the air and fuel entering the fuel cell and to provide energy for district heating. The current work considers instead the possible benefits of using the exhaust gases in an HRSG in order to produce steam which drives a steam turbine for additional power output. Four different steam turbine cycles are considered in this M.S. thesis work: a single-pressure, a dual-pressure, a triple-pressure, and a triple-pressure with reheat. The models have been developed to function both at design (full load) and off-design (partial load) conditions. In addition, different solid oxide fuel cell sizes are examined to assure a proper selection of SOFC size based on efficiency or cost. The thermoeconomic analysis includes cost functions developed specifically for the different system and component sizes (capacities) analyzed. A parametric study is used to determine the most viable system/component syntheses/designs based on maximizing total system efficiency or minimizing total system life cycle cost.
Master of Science

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19

LOPEZ, LUIZ A. N. M. "Transformadas de Wavelets e logica Fuzzi na inspecao por Eddy-Current em tubos de geradores de vapor de centrais nucleares." reponame:Repositório Institucional do IPEN, 2002. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11012.

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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

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MESQUITA, ROBERTO N. de. "Classificação de defeitos em tubos de gerador de vapor de plantas nucleares utilizando mapas auto-organizáveis." reponame:Repositório Institucional do IPEN, 2002. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11640.

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Tese (Doutoramento)
IPEN/T
Escola Politecnica, Universidade de São Paulo - POLI/USP

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21

Hoffmann, Alexander [Verfasser], Robert [Akademischer Betreuer] Pitz-Paal, and Uwe [Akademischer Betreuer] Hampel. "Numerical and Experimental Investigation of Transient Two-phase Flow Phenomena in Concentrated Solar Power Plants with Direct Steam Generation / Alexander Hoffmann ; Robert Pitz-Paal, Uwe Hampel." Aachen : Universitätsbibliothek der RWTH Aachen, 2017. http://d-nb.info/1162063718/34.

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22

FORMIGONI, ANDRE L. "Análise de defeitos em tubos de geradores de vapor de usinas nucleares utilizando a transformada de Hilbert-Huang em sinais de inspeção por correntes parasitas." reponame:Repositório Institucional do IPEN, 2012. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10135.

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Dissertação (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

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Santos, Elma Pereira 1982. "Despacho integrado da geração termeletrica e da produção e transporte de gas natural com metodo de Newton." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259919.

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Orientador: Takaaki Ohishi
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
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Resumo: O gás natural é um combustível fóssil que pode ser utilizado tanto na indústria como no comércio, residências e veículos. Uma aplicação importante do gás natural é como fonte primária para geração de energia elétrica em usinas termelétricas. Seu uso possibilita uma maior estabilidade ao Sistema Elétrico Brasileiro, pelo fato de depender menos do nível de água nos reservatórios para atendimento da demanda de energia elétrica. Como o gás natural possui uma estocagem complexa e onerosa, a quantidade de demanda de gás afeta diretamente as suas etapas de produção e transporte, já que toda a quantidade produzida e transportada deverá ser consumida. Desse modo, a operação do sistema de suprimento de gás natural é fortemente dependente das decisões de seus consumidores. As usinas termelétricas estão entre os maiores consumidores de gás, de forma que o despacho das usinas termelétricas afeta fortemente a operação do sistema de gás. Por outro lado, restrições no sistema de suprimento de gás também podem afetar a operação das usinas termelétricas. Esta forte dependência operativa entre estes dois sistemas requer uma operação coordenada para se obter uma operação mais eficiente e segura. Esta tese apresenta um modelo de despacho econômico aplicado a usinas termelétricas que usam gás natural como fonte primária, considerando os custos de produção, transporte de gás natural e de geração de energia elétrica. A modelagem matemática resulta em um problema misto não linear. Para resolução foi utilizada uma abordagem híbrida, que combina um modelo baseado em Programação Linear e um modelo não linear. O problema não linear é resolvido através do método de Newton.
Abstract: Natural gas is a fossil fuel that can be used in industry, trade, residence and vehicles, among others. An important application of natural gas is as a primary source for electricity generation in thermoelectric power plants. In the Brazilian Electric System this source increase the system stability, once it is less dependent of the water level in tanks to serve the demand for power. As natural gas storage it is more complex and expensive, the amount of gas directly affects the production and transportation stages, once the entire amount that is produced and transported must be consumed. Thus, the operation of the supply system of natural gas is strongly dependent on decisions of their consumers. The thermoelectric power plants are among the largest gas consumers, so the dispatch of thermoelectric plants affects strongly the gas system operation. On the other hand, restrictions in the gas supply system may also affect the operation of thermoelectric plants. This strong operative dependence between these two kinds of systems, requires a coordinated operation with the aim of obtaining a more efficient and safer operation. This thesis presents a model of economic dispatch applied to thermoelectric power plants that use natural gas as a primary energy source, considering the costs of production, transportation of the natural gas and electricity generation. The mathematical modeling results in a nonlinear mixed problem. For resolution was used a hybrid approach that combines a model based on Linear Programming and a nonlinear. The nonlinear problem is solved by the Newton's method.
Mestrado
Engenharia de Computação
Mestre em Engenharia Elétrica

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24

Северин, Валерій Петрович, Олена Миколаївна Нікуліна, and Олександр Сергійович Шевцов. "Нелінійні моделі парових турбін АЕС для маневрених режимів експлуатації." Thesis, НТУ "ХПІ", 2017. http://repository.kpi.kharkov.ua/handle/KhPI-Press/33423.

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Побудована нелінійна модель парової турбіни К-1000-60/1500-2 як об’єкта автоматичного керування в відносних змінних стану, що враховує експериментальні дані регулюючих органів і використовує мінімальну кількість обчислень. На основі цієї моделі для дослідження режиму скидання навантаження побудовані графіки зміни змінних тиску та частоти.
A nonlinear model of the steam turbine K-1000-60/1500-2 was constructed as an object of automatic control in relative variables, which takes into account experimental data of regulatory bodies and uses a minimal amount of computations. On the basis of this model, graphs of changes in pressure and frequency variables are constructed for investigating the load reset mode.

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25

Kotze, Johannes Paulus. "Thermal energy storage in metallic phase change materials." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/96049.

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Thesis (PhD) -- Stellenbosch University, 2014.
ENGLISH ABSTRACT: Currently the reduction of the levelised cost of electricity (LCOE) is the main goal of concentrating solar power (CSP) research. Central to a cost reduction strategy proposed by the American Department of Energy is the use of advanced power cycles like supercritical steam Rankine cycles to increase the efficiency of the CSP plant. A supercritical steam cycle requires source temperatures in excess of 620°C, which is above the maximum storage temperature of the current two-tank molten nitrate salt storage, which stores thermal energy at 565°C. Metallic phase change materials (PCM) can store thermal energy at higher temperatures, and do not have the drawbacks of salt based PCMs. A thermal energy storage (TES) concept is developed that uses both metallic PCMs and liquid metal heat transfer fluids (HTF). The concept was proposed in two iterations, one where steam is generated directly from the PCM – direct steam generation (DSG), and another where a separate liquid metal/water heat exchanger is used – indirect steam generation, (ISG). Eutectic aluminium-silicon alloy (AlSi12) was selected as the ideal metallic PCM for research, and eutectic sodium-potassium alloy (NaK) as the most suitable heat transfer fluid. Thermal energy storage in PCMs results in moving boundary heat transfer problems, which has design implications. The heat transfer analysis of the heat transfer surfaces is significantly simplified if quasi-steady state heat transfer analysis can be assumed, and this is true if the Stefan condition is met. To validate the simplifying assumptions and to prove the concept, a prototype heat storage unit was built. During testing, it was shown that the simplifying assumptions are valid, and that the prototype worked, validating the concept. Unfortunately unexpected corrosion issues limited the experimental work, but highlighted an important aspect of metallic PCM TES. Liquid aluminium based alloys are highly corrosive to most materials and this is a topic for future investigation. To demonstrate the practicality of the concept and to come to terms with the control strategy of both proposed concepts, a storage unit was designed for a 100 MW power plant with 15 hours of thermal storage. Only AlSi12 was used in the design, limiting the power cycle to a subcritical power block. This demonstrated some practicalities about the concept and shed some light on control issues regarding the DSG concept. A techno-economic evaluation of metallic PCM storage concluded that metallic PCMs can be used in conjunction with liquid metal heat transfer fluids to achieve high temperature storage and it should be economically viable if the corrosion issues of aluminium alloys can be resolved. The use of advanced power cycles, metallic PCM storage and liquid metal heat transfer is only merited if significant reduction in LCOE in the whole plant is achieved and only forms part of the solution. Cascading of multiple PCMs across a range of temperatures is required to minimize entropy generation. Two-tank molten salt storage can also be used in conjunction with cascaded metallic PCM storage to minimize cost, but this also needs further investigation.
AFRIKAANSE OPSOMMING: Tans is die minimering van die gemiddelde leeftydkoste van elektrisiteit (GLVE) die hoofdoel van gekonsentreerde son-energie navorsing. In die kosteverminderingsplan wat voorgestel is deur die Amerikaanse Departement van Energie, word die gebruik van gevorderde kragsiklusse aanbeveel. 'n Superkritiese stoom-siklus vereis bron temperature hoër as 620 °C, wat bo die 565 °C maksimum stoor temperatuur van die huidige twee-tenk gesmelte nitraatsout termiese energiestoor (TES) is. Metaal fase veranderingsmateriale (FVMe) kan termiese energie stoor by hoër temperature, en het nie die nadele van soutgebaseerde FVMe nie. ŉ TES konsep word ontwikkel wat gebruik maak van metaal FVM en vloeibare metaal warmteoordrag vloeistof. Die konsep is voorgestel in twee iterasies; een waar stoom direk gegenereer word uit die FVM (direkte stoomopwekking (DSO)), en 'n ander waar 'n afsonderlike vloeibare metaal/water warmteruiler gebruik word (indirekte stoomopwekking (ISO)). Eutektiese aluminium-silikon allooi (AlSi12) is gekies as die mees geskikte metaal FVM vir navorsingsdoeleindes, en eutektiese natrium – kalium allooi (NaK) as die mees geskikte warmteoordrag vloeistof. Termiese energie stoor in FVMe lei tot bewegende grens warmteoordrag berekeninge, wat ontwerps-implikasies het. Die warmteoordrag ontleding van die warmteruilers word aansienlik vereenvoudig indien kwasi-bestendige toestand warmteoordrag ontledings gebruik kan word en dit is geldig indien daar aan die Stefan toestand voldoen word. Om vereenvoudigende aannames te bevestig en om die konsep te bewys is 'n prototipe warmte stoor eenheid gebou. Gedurende toetse is daar bewys dat die vereenvoudigende aannames geldig is, dat die prototipe werk en dien as ŉ bevestiging van die konsep. Ongelukkig het onverwagte korrosie die eksperimentele werk kortgeknip, maar dit het klem op 'n belangrike aspek van metaal FVM TES geplaas. Vloeibare aluminium allooie is hoogs korrosief en dit is 'n onderwerp vir toekomstige navorsing. Om die praktiese uitvoerbaarheid van die konsep te demonstreer en om die beheerstrategie van beide voorgestelde konsepte te bevestig is 'n stoor-eenheid ontwerp vir 'n 100 MW kragstasie met 15 uur van 'n TES. Slegs AlSi12 is gebruik in die ontwerp, wat die kragsiklus beperk het tot 'n subkritiese stoomsiklus. Dit het praktiese aspekte van die konsep onderteken, en beheerkwessies rakende die DSO konsep in die kollig geplaas. In 'n tegno-ekonomiese analise van metaal FVM TES word die gevolgtrekking gemaak dat metaal FVMe gebruik kan word in samewerking met 'n vloeibare metaal warmteoordrag vloeistof om hoë temperatuur stoor moontlik te maak en dat dit ekonomies lewensvatbaar is indien die korrosie kwessies van aluminium allooi opgelos kan word. Die gebruik van gevorderde kragsiklusse, metaal FVM stoor en vloeibare metaal warmteoordrag word net geregverdig indien beduidende vermindering in GLVE van die hele kragsentrale bereik is, en dit vorm slegs 'n deel van die oplossing. ŉ Kaskade van verskeie FVMe oor 'n reeks van temperature word vereis om entropie generasie te minimeer. Twee-tenk gesmelte soutstoor kan ook gebruik word in samewerking met kaskade metaal FVM stoor om koste te verminder, maar dit moet ook verder ondersoek word.

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Spelling, James. "Steam Turbine Optimisation for Solar Thermal Power Plant Operation." Licentiate thesis, KTH, Kraft- och värmeteknologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-35386.

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The provision of a sustainable energy supply is one of the most important issues facing humanity at the current time, given the strong dependence of social and economic prosperity on the availability of affordable energy and the growing environmental concerns about its production. Solar thermal power has established itself as a viable source of renewable power, capable of generating electricity at some of the most economically attractive rates. Solar thermal power plants are based largely on conventional Rankine-cycle power generation equipment, reducing the technological risk involved in the initial investment. Nevertheless, due to the variable nature of the solar supply, this equipment is subjected to a greater range of operating conditions than would be the case in conventional systems. The necessity of maintaining the operational life of the steam-turbines places limits on the speed at which they can be started once the solar supply becomes available. However, in order to harvest as much as possible of the Sun’s energy, the turbines should be started as quickly as is possible. The limiting factor in start-up speed being the temperature of the metal within the turbines before start-up, methods have been studied to keep the turbines as warm as possible during idle-periods. A detailed model of the steam-turbines in a solar thermal power plant has been elaborated and validated against experimental data from an existing power plant. A dynamic system model of the remainder of the plant has also been developed in order to provide input to the steam-turbine model. Three modifications that could potentially maintain the internal temperature of the steam-turbines have been analysed: installation of additional insulation, increasing the temperature of the gland steam and use of external heating blankets. A combination of heat blankets and gland steam temperature increase was shown to be the most effective, with increases in electricity production of up to 3% predicted on an annual basis through increased availability of the solar power plant.
Hållbar energiförsörjning är för närvarande en av de viktigaste frågorna för mänskligheten. Socialt och ekonomiskt välstånd är starkt kopplat till rimliga energipriser och hållbar energiproduktion. Koncentrerad solenergi är nu etablerad som en tillförlitlig källa av förnybar energi och är också ett ekonomiskt attraktivt alternativ. Koncentrerade solenergikraftverk bygger till stor del på konventionella Rankine-cykel elgeneratorer, vilka minskar de tekniskt relaterade riskerna i den initiala investeringen. På grund av solstrålningens skiftande karaktär utsätts denna utrustning för mer varierade driftsförhållanden, jämfört med konventionella system. Behovet av att bibehålla den operativa livslängden på ångturbiner sätter gränser för uppstartshastigheten. För att utnyttja så mycket som möjligt av solens energi bör ångturbinen startas så snabbt som möjligt när solstrålningen blir tillgänglig. Eftersom temperaturen i metalldelar hos turbinerna är den begränsande faktorn, har metoder studerats för att hålla turbinerna så varma som möjligt under tomgångsperioder. En detaljerad modell av ångturbiner i ett solenergikraftverk har utvecklats och validerats mot experimentella data från ett befintligt kraftverk. En dynamisk systemmodell av de övriga delarna av anläggningen har också utvecklats för att ge input till ångturbinsmodellen. Tre modifieringar som potentiellt kan bidra till att upprätthålla den inre temperaturen i ångturbiner har analyserats: montering av ytterligare isolering, ökning av temperaturen hos glänsångan och användning av elvärmefiltar. En kombination av elvärmefiltar och en temperaturökning av glänsångan visade sig vara det mest effektiva alternativet. Åtgärderna resulterade i en ökad elproduktion på upp till 3%, beräknat på årsbasis genom ökad tillgänglighet hos kraftverket.
QC 20110629
TURBOKRAFT

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Topel, Monika. "Improving Concentrating Solar Power Plant Performance through Steam Turbine Flexibility." Doctoral thesis, KTH, Kraft- och värmeteknologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-211780.

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The amount of incoming solar energy to earth is greater than any other source. Among existing technologies to harness solar energy there is concentrating solar power (CSP). One advantage of CSP is that is dispatchable, meaning that it can provide power even when the sun is not shining. However, CSP is undergoing challenges which hinder its development such as operating variabilities caused by the fluctuations of the sun or the fact that these systems are not yet cost competitive with respect to other technologies. One way of improving the performance of CSP plants (CSPPs) is by increasing their operational flexibility, specifically their capability for fast starts. In this way it is possible for the CSPP to harness the solar energy as soon as possible, thus producing more energy and increasing its profitability. Over 90% of CSPPs use a steam turbine to generate electricity. Steam turbines are not currently designed with the flexibility required by the CSP application. Steam turbine start-up is limited by thermal stress and differential expansion. If not carefully controlled, these phenomena either consume lifetime or even result in machine failure. The aim of this work was to understand the improvement potential of steam turbine start-up and quantify this in terms of CSPP performance indicators. For this, a thermo-mechanical steam turbine model was developed and validated. The model was then used to analyze potential improvements and thermal constraints to steam turbine start-up operation. Furthermore, a CSP plant techno-economic model was developed including steam turbine details. This modeling approach including two levels of detail allowed for the particularities of the component to be included within the dynamics of the plant and thus be able to connect the perspectives of the equipment manufacturer with those of the plant operator. Reductions of up to 11.4% in the cost of electricity were found in the studies carried out.

QC 20170814

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Safyel, Zerrin Supervisor :. Yeşin Tülay. "Enhancement of the bottoming cycle in a gas/steam combined cycle power plant." Ankara : METU, 2005. http://etd.lib.metu.edu.tr/upload/2/12605896/index.pd.

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Mobbs, Rebecca-Louise. "Cyclic steam oxidation of a steel for biomass power plant application." Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8205/.

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Austenitic stainless steels are commonly used as heat exchanger tubing in power plants. As a result, this class of steels have been optimised to withstand high temperatures and pressures. However, under these conditions, the alloy will experience oxidation which greatly affects the lifetime of the materials. The increased likelihood of more cyclic operating conditions means a greater level of understanding of the oxidation and spallation behaviour of these alloys is required. High temperature oxidation studies available in the literature principally emphasise isothermal oxidation of flat plates rather than curved surfaces representative of boiler tubing. The isothermal and cyclic steam oxidation and spallation behaviour of TP347H FG was studied in this thesis. Electron microscopy and elemental characterisation showed the oxide encompasses an inner Fe-Cr-Ni spinel and an outer magnetite layer. A haematite layer forms during initial stages of oxidation in air-saturated steam conditions similar to the oxides formed in plant. The use of a novel technique, termed STORME, made it possible to identify the chemistry of the spalled oxide and also allowed calculations of the interfacial fracture energy to be made and the spallation mechanism to be identified. Modelling of the spallation observed enables predictions of spallation behaviour to be made.

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Qur'an, Omar Ali Sammour. "Design criteria and performance of steam turbines in a CPP plant for electrical power generation." Thesis, University of Hertfordshire, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247306.

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Khabrana, Ahmed, and Jaber Ageeli. "Producing Electricity in Power Plant." Thesis, Blekinge Tekniska Högskola, Institutionen för tillämpad signalbehandling, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-1979.

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Abstract This Bachelor thesis has been written at the Blekinge Institute of Technology. The thesis describes electricity production in Shoaiba Steam Power plant in Saudi Arabia. Shoaiba Power Plant is located 100 km South of Jeddah city in Saudi Arabia. Total power production ability reaches 4400 MW. Shoaiba Power Plant has two stages and is constructed with 11 units, each unit produces 400 MW at line voltage 24 kV and line current 16 kA. Main pieces of equipment and their function in the station are as follows: A Steam Generator (boiler), produces steam by burning natural gas or crude oil in the furnace. The steam is superheated and is passed into a steam turbine, which converts the thermal energy of the steam into mechanical power, in form of rotary motion. The turbine drives a generator, which converts the rotary energy of the turbine into electric power. Steam generator, steam turbine and electrical generator are components that are described in the thesis. When the flow of steam to the turbine is controlled, then the amount of thermal energy that changes to mechanical energy in the steam turbine is controlled. The electrical generator is where the final energy conversion takes place. The mechanical energy from the turbine is converted by the generator into electrical energy, which is transmitted to the service area by help of electrical transmission lines. The plant cycle is an essential part of the energy flow path. Without the plant cycle, the conversion of thermal energy into mechanical energy would not occur, The plant cycle is a closed loop that allows the same water to be used over and over again. Always, the power plants are situated far from residential areas and located outside cities and close to the sea, because the steam is produced from seawater. The advantages of the steam power stations are as follows: They can produce high amounts of electrical energy from small amounts of fuel. They have low initial costs, obstetrics and maintenance costs are not high, and the stations do not need much space to be built and they have usually high capacity. The disadvantages of steam stations are the following: They cause environmental pollution, they have low efficiency, and require very big quantities of cooling water, and the stations must be built away from populated areas.
Conclusion: Converting in steam power plant is one of many ways to produce electrical energy in the world. It can be done in any country because it can be done with different chemical sources. In Saudi Arabia we use oil, because it easier and cheaper than any other chemical source for us. As any country would use what is better for them. The thesis has described circulation system in Shoaiba power plant by converting chemical energy to thermal energy in the boiler, then the turbine converts thermal energy to mechanical energy. Then the mechanical energy is converted to electrical energy in the generator. The advantages of the steam stations are as follows: production of high amounts of electrical energy from small amounts of fuel, low cost of the initial costs, obstetrics and maintenance costs are not high, the station does not need much space to build and they are usually high capacity. The disadvantages of steam stations are the following: environmental pollution, low efficiency, requires very big amounts of cooling water, and these stations must be built away from population areas.
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Horkeby, Kristofer. "Simulation of Heat Recovery Steam Generator in a Combined Cycle Power Plant." Thesis, Linköpings universitet, Institutionen för systemteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-75836.

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This thesis covers the modelling of a Heat Recovery Steam Generator (HRSG) in a Combined Cycle Power Plant(CCPP). This kind of power plant has become more and more utilized because of its high efficiency and low emissions. The HRSG plays a central role in the generation of steam using the exhaust heat from the gas turbine. The purpose of the thesis was to develop efficient dynamic models for the physical components in the HRSG using the modelling and simulation software Dymola. The models are then to be used for simulations of a complete CCPP.The main application is to use the complete model to introduce various disturbances and study their consequences inthe different components in the CCPP by analyzing the simulation results. The thesis is a part of an ongoingdevelopment process for the dynamic simulation capabilities offered by the Solution department at SIT AB. First, there is a theoretical explanation of the CCPP components and control system included in the scope of this thesis. Then the development method is described and the top-down approach that was used is explained. The structure and equations used are reported for each of the developed models and a functional description is given. Inorder to ensure that the HRSG model would function in a complete CCPP model, adaptations were made and tuning was performed on the existing surrounding component models in the CCPP. Static verifications of the models are performed by comparison to Siemens in-house software for static calculations. Dynamic verification was partially done, but work remains to guarantee the validity in a wide operating range. As a result of this thesis efficient models for the drum boiler and its control system have been developed. An operational model of a complete CCPP has been built. This was done integrating the developed models during the work with this thesis together with adaptations of already developed models. Steady state for the CCPP model is achieved during simulation and various disturbances can then be introduced and studied. Simulation time for a typical test case is longer than the time limit that has been set, mainly because of the gas turbine model. When using linear functions to approximate the gas turbine start-up curves instead, the simulation finishes within the set simulation time limit of 5 minutes for a typical test case.

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Safyel, Zerrin. "Enhancement Of The Bottoming Cycle In A Gas/steam Combined Cycle Power Plant." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/2/12605896/index.pdf.

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A combined cycle gas/steam power plant combines a gas turbine (topping cycle) with a steam power plant (bottoming cycle) through the use of a heat recovery steam generator. It uses the hot exhaust of the gas turbine to produce steam which is used to generate additional power in the steam power plant. The aim of this study is to establish the different bottoming cycle performances in terms of the main parameters of heat recovery steam generator and steam cycle for a chosen gas turbine cycle. First of all
for a single steam power cycle, effect of main cycle parameters on cycle performance are analyzed based on first law of thermodynamics. Also, case of existence of a reheater section in a steam cycle is evaluated. For a given gas turbine cycle, three different bottoming cycle configurations are chosen and parametric analysis are carried out based on energy analysis to see the effects of main cycle parameters on cycle performance. These are single pressure cycle, single pressure cycle with supplementary firing and dual pressure cycle. Also, effect of adding a single reheat to single pressure HRSG is evaluated. In single pressure cycle, HRSG generates steam at one pressure level. In dual pressure cycle, HRSG generates steam at two different pressure levels. i.e. high pressure and low pressure. In single pressure cycle with supplementary firing excess oxygen in exhaust gas is fired before entering HRSG by additional fuel input. So, temperature of exhaust gas entering the HRSG rises. Second law analysis is performed to able to see exergy distribution throughout the bottoming plant
furthermore second law efficiency values are obtained for single and dual pressure bottoming cycle configurations as well as basic steam power cycle with and without reheat. It is shown that maximum lost work due to irreversibility is in HRSG for a bottoming cycle in a single pressure gas / steam combined power plant and in boiler for a steam cycle alone. Comparing this with the single pressure cycle shows how the dual pressure cycle makes better use of the exhaust gas in the HRSG that dual pressure combined cycle has highest efficiency values and lost work due to irreversibility in -most significant component- HRSG can be lowered. And also it is shown that by extending the idea of reheat the moisture content is reduced and improvement in the performance is possible for high main steam pressures. Another observation is that supplementary firing increases the steam turbine output compared to the cycle without supplementary firing. The efficiency rises slightly for HP steam pressures higher than 14 MPa at HRSG exit, because the increased steam production also results in increased mass flows removing more energy from the exhaust gas.

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Godswill, Uchechukwu Megwai. "Process Simulations of Small Scale Biomass Power Plant." Thesis, Högskolan i Borås, Institutionen Ingenjörshögskolan, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-17969.

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Power generation from biomass based renewable energy technologies is a promising option in retrofitting our dependence in conventional power generation processes. The development of any society is not possible without sustainable energy and access to energy creates that environment that allows the world to thrive. Electricity access especially in developing regions of the world is of particular interest. This work provides results on electricity efficiency, the economic feasibility and environmental impact of biomass based power technologies in small scale setting using Aspen Plus software. The power generation processes analysed on standalone basis include - micro gas turbine, gas turbine, steam turbine, Stirling engine and internal combustion engine. Some of the processes are optimized in the design to suit the specific climate and available wood waste stream in Nigeria is considered in this work. Simulation results indicate that gas engines power technologies gave a better electric performance of more than 30% with its integration with biomass gasification technology in production of fuel gas. The stirling engine power technology shows a good prospect despite its yet to be commercial status. The modification of the engine (removal regenerator) gives a better electric efficiency. Also result shows that internal combustion engine process emits more of nitric oxides compared to other technologies which create doubts over its environmental compatibility. Economic studies show that for small scale power generation, internal combustion engines and stirling engines are economic feasible. Also, steam turbine and gas turbine illustrate why they are mostly applied in medium/large scale biomass power generation specially recommended to regions where more biomass resource are produced. The micro gas turbine power technology can also be applied in small scale despite its high total investment capital. Furthermore, the study shows that about from 1.8 million tonnes per year of saw dust (wood waste) produced from lumber industries in Nigeria, about 1.3 TWh of electricity can be generated from 1000 MW power plant. Power generation via the utilization of biomass prove to be a possible path to Nigeria’s economic, social and environmental sustainability but the extent to which this can achieved is strongly dependent institutional framework, investment, incentives and information policies.
Program: Masterutbildning i energi- och materialåtervinning

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Pieters, Alfred Cornelius. "Whip restraint for a steam pipe rupture event on a nuclear power plant / Alfred Cornelius Pieters." Thesis, North-West University, 2013. http://hdl.handle.net/10394/9391.

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One of the requirements of a safe nuclear power plant design is the postulation of the dynamic effects of a steam pipe rupture. The dynamic effects are the discharging fluid and pipe whip on structures, systems or components. A pipe rupture can be caused in the steam pipe system where a defect such as a crack exists. Multiple factors contribute to the initiation of pipe cracks during the plant’s life. Cracks may start microscopically small and over time, with the assistance of cyclic operation, fatigue may elongate the crack. When a steam pipe is cooled by water during an accident, steam condensate may accumulate and form slugs of water. This water will have an effect on the system termed condensation induced water hammer. The cause of the pipe rupture is not addressed in this dissertation. Pipe rupture can be considered to be either a circumferential or longitudinal break. For the purpose of this dissertation only a circumferential break will be considered. This research is based on the development of a pipe whip restraint structure to protect the plant environment during a steam pipe rupture event in a nuclear power plant. It focuses on a structural component required to restrain the dynamic energy to an acceptable level. Whip restraints used in the nuclear industry are typically honeycomb, U-bar and crush pipe types. In this dissertation only the U-bar and crush pipe whip restraints will be considered. The plant environment, with regards to pipe layout, plays a large role in determining the type of restraint to be used, whether it is U-bar or crush pipe. A whip towards the wall/structure will favor a crush pipe; a whip away from the wall/structure will favor a U-bar restraint. In this project the crush pipe is selected where the whip is towards a wall/structure. The crush pipe also represents a simpler design. First-order analysis is performed using the energy method to determine the conceptual geometry of the whipping component and the restraint geometry. Second-order analysis includes finite element analysis to verify the first-order results. In this dissertation the concept validation is done using LS-PrePost. for the pre- and post-processing while the analysis is performed using LS-DYNA ®. During the second-order analysis it was demonstrated that the energy is successfully absorbed by the crush pipe and thus the first-order analysis is considered adequate.
Thesis (MIng (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2013

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Desai, Ranjit. "Thermo-Economic Analysis of a Solar Thermal Power Plant with a Central Tower Receiver for Direct Steam Generation." Thesis, KTH, Kraft- och värmeteknologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-131764.

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Jayasinghe, Prabodha. "Development of a tool for simulating performance of sub systems of a combined cycle power plant." Thesis, KTH, Energiteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-99164.

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Abstract In Sri Lanka, around 50% of the electrical energy generation is done using thermal energy, and hence maintaining generation efficiencies of thermal power plants at an acceptable level is very important from a socio-economic perspective for the economic development of the country. Efficiency monitoring also plays a vital role as it lays the foundation for maintaining and improving of generation efficiency. Heat rate, which is the reciprocal of the efficiency, is used to measure the performance of thermal power plants. In combined cycle power plants, heat rate depends on ambient conditions and efficiencies of subsystems such as the gas turbine, Heat Recovery Steam Generator (HRSG), steam turbine, condenser, cooling tower etc. The heat rate provides only a macroscopic picture of the power plant, and hence it is required to analyse the efficiency of each subsystem in order to get a microscopic picture. Computer modelling is an efficient method which can be used to analyse the each subsystem of a combined cycle power plant. Objective of this research is to develop a computer based tool which simulates the performance of subsystems of a combined cycle power plant in Sri Lanka. At the inception of the research, only heat rate was measured, and performances of subsystem were unknown. During the analysis, plant is divided into main systems, in order to study them macroscopically. Then, these main systems are divided into subsystems in order to have a microscopic view. Engineering equation solver (EES) was used to develop the tool, and the final computer model was linked with Microsoft excel package for data handling. Final computer model is executed using both present and past operating data in order to compare present and past performance of the power plant. In combined cycle power plants steam is injected into the gas turbine to reduce the NOx generation and this steam flow is known as NOx flow. According to the result it was evident that turbine efficiency drops by 0.1% and power output increase by 1MW when NOx flow increases from 4.8 to 6.2kg/s. Further it was possible to conclude that gas turbine efficiency drop by 0.1% when ambient temperature increased by 3 C; and gas turbine power output decrease by 2MW when ambient temperature increases from 27 to 31 degrees. Regarding the steam cycle efficiency it was found that steam turbine power output drops by 0.5MW when ambient temperature increases from 27 to 31 degrees; and steam cycle efficiency increases by 1% when NOx flow increases from 4.8 to 6.2kg/s. Further, steam turbine power output decreases by 0.25MW When NOx flow increases from 4.8 to 6.2kg/s Heat rate, which is the most important performance index of the power plant, increases by 10units (kJ/kWh) when ambient temperature increases by 3 C. Heat rate also increases with raising NOx flow which was 6.2kg/s in 2007 and 4.2kg/s in 2011. Hence, heat rate of the power plant has improved (decreased) by 10units (kJ/kWh) from 2007 to 2011. Other than above, following conclusions were also revealed during the study. 1) HRSG efficiency has not change during past 4 years 2) Significant waste heat recovery potential exists in the gas turbine ventilation system in the form of thermal energy

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Ellakany, Farid. "Enhancing the Thermo-Economic Performance of a Direct Steam Generation Solar Tower Power Plant through the Implementation of Steam Flow Control Strategies for Flexible Operation." Thesis, KTH, Kraft- och värmeteknologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-150112.

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Above 90% of the current installed concentrating solar power plants are based on conventional steam-turbine cycles. The operation of steam turbines in these plants is distinctive when compared to traditional base-load power plants. The reason goes back to the intermittent nature of solar power which, in the absence of thermal energy storage or a back-up combustion boiler, forces plant operators to shut down the turbines during night time or at times of low solar radiation. Furthermore, such intermittency often leads to undesirable off-design turbine operating circumstances, either by load variations or changes on live-steam conditions.The present study examines the influence of implementing two operating strategies dealing with steam flow control as a function of incoming solar power for enhancing the thermo-economic performance of a direct steam generation solar tower power plant. The first one consists of a simultaneous high pressure turbine stage- and feed-water preheater bypass. This strategy is used during periods in which the solar radiation is higher than nominal. On these occasions, the plant is capable of generating a larger flow of steam, which allows for an increase in the power production when inserting the additional steam in the turbine bypass. On the other hand, the second operating strategy consists of using an additional feed-water preheater when the power from the field is lower than nominal. In this way, the feed water can reach a higher temperature prior entering the boiler, which is not only beneficial during times of cloud-passages, but also during the start-up process.A dynamic model of a direct steam generation solar tower power plant has been developed following design and operation specifications of an existing reference plant. The two proposed strategies were implemented to the reference model, then a whole year worth simulation was performed for both the reference and the modified models. Lastly, the thermodynamic and economic performance of both systems was measured for the purpose of comparison, by means of using KTH in-house tool DYESOPT. Results show that the implementation of the proposed strategies can enhance the economic viability of the systems by yielding a reduction of 8.7% on the levelized cost of electricity, mainly due to allowing achieving a 12% increase in the net electricity production.

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Alie, Colin F. "CO₂ capture with MEA integrating the absorption process and steam cycle of an existing coal-fired power plant /." Waterloo, Ont. : University of Waterloo, 2004. http://etd.uwaterloo.ca/etd/calie2004.pdf.

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Thesis (M.A.Sc.)--University of Waterloo, 2004.
Contains hypertext links. "A thesis presented to the University of Waterloo in fulfilment of the thesis requirement for the degree of Master of Applied Science in Chemical Engineering". Includes bibliographical references.

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Barner, Robert Buckner. "Power conversion unit studies for the next generation nuclear plant coupled to a high-temperature steam electrolysis facility." Texas A&M University, 2006. http://hdl.handle.net/1969.1/4835.

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The Department of Energy and the Idaho National Laboratory are developing a Next Generation Nuclear Plant (NGNP) to serve as a demonstration of state-of-the-art nuclear technology. The purpose of the demonstration is two fold: 1) efficient low cost energy generation and 2) hydrogen production. Although a next generation plant could be developed as a single-purpose facility, early designs are expected to be dual-purpose. While hydrogen production and advanced energy cycles are still in their early stages of development, research towards coupling a high temperature reactor, electrical generation and hydrogen production is under way. Many aspects of the NGNP must be researched and developed to make recommendations on the final design of the plant. Parameters such as working conditions, cycle components, working fluids, and power conversion unit configurations must be understood. Three configurations of the power conversion unit were modeled using the process code HYSYS; a three-shaft design with 3 turbines and 4 compressors, a combined cycle with a Brayton top cycle and a Rankine bottoming cycle, and a reheated cycle with 3 stages of reheat were investigated. A high temperature steam electrolysis hydrogen production plant was coupled to the reactor and power conversion unit by means of an intermediate heat transport loop. Helium, CO2, and an 80% nitrogen, 20% helium mixture (by weight) were studied to determine the best working fluid in terms cycle efficiency and development cost. In each of these configurations the relative heat exchanger size and turbomachinery work were estimated for the different working fluids. Parametric studies away from the baseline values of the three-shaft and combined cycles were performed to determine the effect of varying conditions in the cycle. Recommendations on the optimal working fluid for each configuration were made. The helium working fluid produced the highest overall plant efficiency for the three-shaft and reheat cycle; however, the nitrogen-helium mixture produced similar efficiency with smaller component sizes. The CO2 working fluid is recommend in the combined cycle configuration.

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Le, Grange Willie. "Component development for a high fidelity transient simulation of a coal-fired power plant using Flownex SE." Master's thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/29863.

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Large coal-fired power stations are designed to be run predominantly at full load and optimum conditions. The behaviour of plants, operating at low load and varying conditions, is getting more and more attention due to the introduction of variable renewable generation on the grid. Consequently, the need for a fully transient high-fidelity system based model has grown, as this will enable one to study the behaviour of plants under such non-ideal conditions. This report details the development of a feedwater heater, deaerator and turbine component for such a high-fidelity transient system model using the Flownex Simulation Environment, a onedimensional thermohydraulic network solver. The components have been modelled all with the aim of using minimal design input data. The feedwater heater component model includes transient effects and thermodynamic relations to represent aspects such as heater performance, level control and transient inertia. In determining the heat transfer characteristics, the model makes use of plant-performance data and correlates the amount of heat transfer by using the feedwater mass flow as the load indicating parameter. This approach eliminates the need for specific geometrical details to calculate the effective heat transfer area. The level control is modelled by using a level representation built from using heat exchanger design methods. The turbine component is modelled by using Fuls’ Semi-Ellipse law or the pressure drop modelling and Ray’s semi-empirical method for the efficiency modelling. The model also contains transient effects, which include thermal inertia due to the shaft and casing, and rotational inertia due to the shaft. The deaerator component is modelled by adapting the model presented by Banda, and modifying the model to work under various conditions. This involved using curve fit methods in Flownex to use input data to model the pressure drop over the main condensate valve. Each of the mentioned components was validated and verified with plant data and finally packaged into a compound component which is a component consisting of a subnetwork in Flownex. These compound components further contain design inputs which are easily accessible by the user. The component models were integrated into larger networks in which various scenarios can be run. A short transient scenario was run on the low-pressure feedwater train of a specific power station. The scenario involved a turbine trip where the bled steam valves for the heaters were closed suddenly. The speed of the valves closing was however unknown and after closing the valves in approximately 10 seconds, results agreed relatively well with plant data. This illustrated the short transient capabilities of the feedwater heater component model. The three component models (feedwater heater, turbine and deaerator) were finally integrated into a regenerative Rankine cycle and was set up using minimal design data. The boiler, condenser and condensate pump were set as boundary conditions in the network but all extraction points for the network were connected. Steady-state results were obtained for various load cases and the main temperature, flow and pressure results were compared. Results agree well with plant data, even at low load conditions

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Alipour, Yousef. "High temperature corrosion in a biomass-fired power boiler : Reducing furnace wall corrosion in a waste wood-fired power plant with advanced steam data." Licentiate thesis, KTH, Yt- och korrosionsvetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-121155.

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The use of waste (or recycled) wood as a fuel in heat and power stations is becoming more widespread in Sweden (and Europe), because it is CO2 neutral with a lower cost than forest fuel. However, it is a heterogeneous fuel with a high amount of chlorine, alkali and heavy metals which causes more corrosion than fossil fuels or forest fuel. A part of the boiler which is subjected to a high corrosion risk is the furnace wall (or waterwall) which is formed of tubes welded together. Waterwalls are made of ferritic low-alloyed steels, due to their low price, low stress corrosion cracking risk, high heat transfer properties and low thermal expansion. However, ferritic low alloy steels corrode quickly when burning waste wood in a low NOx environment (i.e. an environment with low oxygen levels to limit the formation of NOx). Apart from pure oxidation two important forms of corrosion mechanisms are thought to occur in waste environments: chlorine corrosion and alkali corrosion. Although there is a great interest from plant owners to reduce the costs associated with furnace wall corrosion very little has been reported on wall corrosion in biomass boilers. Also corrosion mechanisms on furnace walls are usually investigated in laboratories, where interpretation of the results is easier. In power plants the interpretation is more complicated. Difficulties in the study of corrosion mechanisms are caused by several factors such as deposit composition, flue gas flow, boiler design, combustion characteristics and flue gas composition. Therefore, the corrosion varies from plant to plant and the laboratory experiments should be complemented with field tests. The present project may thus contribute to fill the power plant corrosion research gap. In this work, different kinds of samples (wall deposits, test panel tubes and corrosion probes) from Vattenfall’s Heat and Power plant in Nyköping were analysed. Coated and uncoated samples with different alloys and different times of exposure were studied by scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDX), X-ray diffraction (XRD) and light optical microscopy (LOM). The corrosive environment was also simulated by Thermo-Calc software. The results showed that a nickel alloy coating can dramatically reduce the corrosion rate. The corrosion rate of the low alloy steel tubes, steel 16Mo3, was linear and the oxide scale non-protective, but the corrosion rate of the nickel-based alloy was probably parabolic and the oxide much more protective. The nickel alloy and stainless steels showed good corrosion protection behavior in the boiler. This indicates that stainless steels could be a good (and less expensive) alternative to nickel-based alloys for protecting furnace walls. The nickel alloy coated tubes (and probe samples) were attacked by a potassium-lead combination leading to the formation of non-protective potassium lead chromate. The low alloy steel tubes corroded by chloride attack. Stainless steels were attacked by a combination of chlorides and potassium-lead. The Thermo-Calc modelling showed chlorine gas exists at extremely low levels (less than 0.1 ppm) at the tube surface; instead the hydrated form is thermodynamically favoured, i.e. gaseous hydrogen chloride. Consequently chlorine can attack low alloy steels by gaseous hydrogen chloride rather than chlorine gas as previously proposed. This is a smaller molecule than chlorine which could easily diffuse through a defect oxide of the type formed on the steel.

QC 20130423

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Chen, Qiang. "Simulation of thermal plant optimization and hydraulic aspects of thermal distribution loops for large campuses." Texas A&M University, 2005. http://hdl.handle.net/1969.1/2451.

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Following an introduction, the author describes Texas A&M University and its utilities system. After that, the author presents how to construct simulation models for chilled water and heating hot water distribution systems. The simulation model was used in a $2.3 million Ross Street chilled water pipe replacement project at Texas A&M University. A second project conducted at the University of Texas at San Antonio was used as an example to demonstrate how to identify and design an optimal distribution system by using a simulation model. The author found that the minor losses of these closed loop thermal distribution systems are significantly higher than potable water distribution systems. In the second part of the report, the author presents the latest development of software called the Plant Optimization Program, which can simulate cogeneration plant operation, estimate its operation cost and provide optimized operation suggestions. The author also developed detailed simulation models for a gas turbine and heat recovery steam generator and identified significant potential savings. Finally, the author also used a steam turbine as an example to present a multi-regression method on constructing simulation models by using basic statistics and optimization algorithms. This report presents a survey of the author??s working experience at the Energy Systems Laboratory (ESL) at Texas A&M University during the period of January 2002 through March 2004. The purpose of the above work was to allow the author to become familiar with the practice of engineering. The result is that the author knows how to complete a project from start to finish and understands how both technical and nontechnical aspects of a project need to be considered in order to ensure a quality deliverable and bring a project to successful completion. This report concludes that the objectives of the internship were successfully accomplished and that the requirements for the degree of Degree of Engineering have been satisfied.

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Lundqvist, Mårten. "A techno-economic analysis of implementing temperature-maintaining modifications on the steam turbine of a solar thermal power plant." Thesis, KTH, Energiteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-201652.

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This master thesis examines the techno-economic implications of introducing temperature maintaining modifications on the steam turbine in a direct steam generation solar tower power plant. More specifically, the impact on the maintenance requirements and other performance indicators when installing electrical heat blankets as well as increasing the gland steam temperature, was examined. A model of the Ivanpah plant in southern California was inherited and further developed within the KTH in-house tool DYESOPT to then be used for sensitivity studies focusing on examining the effect of the start improvements.The results show that with the assumptions made, the examined start improvements can be used to significantly increase the power output of the Ivanpah plant while at the same time reducing the maintenance requirements. The investment costs of said improvements were also found to be low in relation to their techno-economic benefits, resulting in a significant reduction of the levelized cost of electricity. The conducted sensitivity studies also suggested that the assumption made were not very sensitive, although more accurate assumptions regarding the costs of the turbine start improvements should be looked at during further development.
Detta examensarbete undersöker de tekniska och ekonomiska konsekvenserna av att implementera turbinmodifikationer i syfte att undvika värmeförluster på ett termiskt solkraftverk. Mer specifikt så studerades det hur elektiska värmefiltar samt en ökning av temperaturen på förseglingsångan påverkar ett kraftverkets underhållsbehov samt andra prestationsindikatorer. För att åstadkomma detta ärvdes samt utvecklades en existerande modell av Ivanpah, ett solkraftverk beläget i Kalifornien, USA i KTHs egenutvecklade modelleringsverktyg DYESOPT. Detta verktyg användes sedan i syfte att undersöka effekten av turbinmodifikationerna genom en känslighetsanalys.Resultaten visar att med de antaganden som gjorts så kan de undersökta turbinmodifikationerna öka den årliga kraftproduktionen och samtidigt sänka underhållsbehoven betydligt. Sett till de ekonomiska aspekterna leder detta till en minskning av den sammanlagda kostnaden för att generera elektricitet med de antaganden som gjorts, eftersom investeringskostnaderna relaterade till modifikationerna är låga i relation till deras fördelar. Känslighetsanalysen pekar dessutom på att de gjorda antagandena inte var särskilt känsliga, men att fokus bör ligga på bättre underbyggda antaganden kring turbinmodifikationernas kostnader för att kunna bedöma dess tekno-ekonomiska effekter än bättre.

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Su, Heyin. "Modeling of Proposed Changes to SIUC Central Heating, Air-Conditioning, and Power Plant Incorporating Variable Frequency Drive (VFD) and High Efficiency Turbine." OpenSIUC, 2011. https://opensiuc.lib.siu.edu/theses/708.

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Currently, the Southern Illinois University Carbondale (SIUC) power plant produces steam at high pressure to drive a high pressure (HP) turbine to make a portion of the electrical power needed by campus, then using 969 kPa (125 psig) steam to provide hot water all year, heat buildings, and to operate a low pressure (LP) turbine that powers the compressor of the central air conditioning (A/C) system. In the proposed system, the HP turbine is replaced by a much higher efficiency, multi-level turbine, the LP turbine is replaced with a motor and Variable Frequency Drive (VFD), and a cooling tower is added to condense more possible steam. This thesis has provided computer models to evaluate the economical feasibility of the proposed system, which are written by using Engineering Equation Solver (EES) software. The results of the study are presented in two cases. Case 1 examines the same amount of coal use between current and proposed systems, while Case 2 exames operating the high pressure boiler at the maximum rate. The results are a cost savings of $1,921,000 and $3,604,000 with payback periods of 4 and 2.2 years for Case 1 and Case 2, respectively. The annual primary energy saved and CO2 reduction from this modification was 200,000 GJ and 564,814 moles, respectively.

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Alie, Colin. "CO₂ Capture With MEA: Integrating the Absorption Process and Steam Cycle of an Existing Coal-Fired Power Plant." Thesis, University of Waterloo, 2004. http://hdl.handle.net/10012/796.

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In Canada, coal-fired power plants are the largest anthropogenic point sources of atmospheric CO₂. The most promising near-term strategy for mitigating CO₂ emissions from these facilities is the post-combustion capture of CO₂ using MEA (monoethanolamine) with subsequent geologic sequestration. While MEA absorption of CO₂ from coal-derived flue gases on the scale proposed above is technologically feasible, MEA absorption is an energy intensive process and especially requires large quantities of low-pressure steam. It is the magnitude of the cost of providing this supplemental energy that is currently inhibiting the deployment of CO₂ capture with MEA absorption as means of combatting global warming. The steam cycle of a power plant ejects large quantities of low-quality heat to the surroundings. Traditionally, this waste has had no economic value. However, at different times and in different places, it has been recognized that the diversion of lower quality streams could be beneficial, for example, as an energy carrier for district heating systems. In a similar vein, using the waste heat from the power plant steam cycle to satisfy the heat requirements of a proposed CO₂ capture plant would reduce the required outlay for supplemental utilities; the economic barrier to MEA absorption could be removed. In this thesis, state-of-the-art process simulation tools are used to model coal combustion, steam cycle, and MEA absorption processes. These disparate models are then combined to create a model of a coal-fired power plant with integrated CO₂ capture. A sensitivity analysis on the integrated model is performed to ascertain the process variables which most strongly influence the CO₂ energy penalty. From the simulation results with this integrated model, it is clear that there is a substantial thermodynamic advantage to diverting low-pressure steam from the steam cycle for use in the CO₂ capture plant. During the course of the investigation, methodologies for using Aspen Plus® to predict column pressure profiles and for converging the MEA absorption process flowsheet were developed and are herein presented.

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Netopilová, Petra. "Systémy přeměn energie pro jaderné elektrárny se sodíkem chlazeným reaktorem (SFR)." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-229737.

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The aim of the dissertation is proposing and solving energy convection systems for nuc-lear power plants with a sodium fast reactor of the 4th generation. The first part of the dissertation deals with collection and evaluation of information available about nuclear power plants with sodium fast reactor which use nuclear or non-nuclear reheating to increase thermal efficiency. On the basis of the acquired information, thermal schemes are developed and thermal effi-ciency is determined for the systems working in both Rankine thermal cycle and Brayton thermal cycle. In the further part of the dissertation thermal calculation of the reheater for nuclear and non-nuclear reheating is made for the systems working in Rankine thermal cycle. At the end of this dissertation, an apparatus suitable for these systems is suggested and the systems are evaluated in terms of technical implementation and nuclear safety.

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Hamza, Hamza Ali Adel. "Selection and justification the parameters of diesel power plant with heat recovery system." Thesis, NTU "KhPI", 2017. http://repository.kpi.kharkov.ua/handle/KhPI-Press/31664.

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Dissertation for the degree of candidate of technical sciences in specialty 05.05.03 – engines and power plants. – National Technical University "Kharkiv Polytechnic Institute". – Kharkiv, 2017. The dissertation is devoted to the choice and substantiation of parameters of a diesel power plant with heat recovery system of recycling the secondary heat from diesel engine using the Rankin cycle, which uses the heat of exhaust gases and cooling water systems. As a result of the analysis of the features of a promising power plant with a Hyundai 25/33 engine for the production of electric power at a plant in Iraq, a technological scheme of a comprehensive system for recycling diesel fuel from an electric power station with the additional generation of electricity, heat for heating heavy fuel, condensing technical water from exhaust gases. As a working fluid in the Rankin cycle, it is advisable to use the hot water from the engine cooling system. Using the developed mathematical model of the distillation circuit of the diesel power plant, the design-experimental study of the influence of the ambient temperature on the indicators of the efficiency of heat recovery was performed. When the ambient temperature changes from 0 ° C to 40 ° C, the amount of electric energy generated by the Rankin cycle for the Hyundai H25 / 33 engine increases to 10%. With a single cogeneration unit with a Hyundai H25 / 33 engine and a recycling complex developed, it is possible to get up to 2300 kg of water vapor condensate per day, which is very valuable in Iraq. Based on the results of the study, two variants of the technological scheme (projects A and B) were developed for the modernization of Hyundai diesel power plants. The feasibility study for the NPV method has shown that after the full recovery equipment is put into operation, the maximum achievable profit will be about 1 406 219 $ /year.
Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.05.03 – двигуни та енергетичні установки. – Національний технічний університет "Харківський політехнічний інститут". – Харків, 2017. Дисертація присвячена вибору і обґрунтуванню параметрів дизель-електричної станції з системою утилізації вторинної теплоти дизеля з використанням циклу Ренкіна, що використовує теплоту відпрацьованих газів та системи охолодження. В результаті аналізу особливостей перспективної енергетичної установки з двигуном Hyundai 25/33 для виробництва електричної енергії на заводі в Іраку розроблена технологічна схема комплексної системи утилізації вторинної теплоти дизель-електричної станції з додатковим отриманням електроенергії, теплоти для підігріву важкого палива, конденсації технічної води з відпрацьованих газів двигуна. Для утилізації вторинної теплоти двигуна Hyundai H25/33 запропоновано утилізаційний контур установки, який працює за органічним циклом Ренкіна (ОЦР). В якості робочого тіла в циклі Ренкіна доцільно використовувати воду системи охолодження двигуна. З використанням розробленої математичної моделі утилізаційного контуру дизель-електростанції виконане розрахунково-експериментальне дослідження впливу температури навколишнього середовища на показники ефективності утилізаційного контуру. При зміні температури навколишнього середовища від 0 ° С до 40 ° С кількість електроенергії, виробленої за циклом Ренкіна для двигуна Hyundai H25/33 збільшується до 10%. При роботі однієї когенераційної установки з двигуном Hyundai H25/33 та розробленим утилізаційним комплексом можна отримати на добу до 2300 кг конденсату водяної пари, що є дуже цінною в Іраку. На основі результатів дослідження було розроблено два варіанта технологічної схеми (проекти "А" та "Б") модернізації дизельних електростанцій компанії Hyundai Heavy Industries. Виконана техніко-економічна оцінка проектів за метод NPV показала, що після того, як обладнання утилізаційного контуру в повному обсязі буде введено у експлуатацію, максимально досяжний прибуток складе близько 1 406 219 дол. США/рік.

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Oliveira, Junior Valter Barbosa de. "Modelagem de central termelétrica a vapor para simulação dinâmica." Universidade Federal do Espírito Santo, 2009. http://repositorio.ufes.br/handle/10/6220.

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Made available in DSpace on 2016-12-23T14:07:27Z (GMT). No. of bitstreams: 1 Dissertacao de Valter Barbosa de Oliveira Junior.pdf: 5244754 bytes, checksum: 0e5a4d27ed2f4da1d96089d0041ddaaa (MD5) Previous issue date: 2009-08-28
Centrais termelétricas a vapor são capazes de utilizar biomassa e fazer o reaproveitamento de resíduos agrícolas, resíduos urbanos ou subprodutos industriais para produzir energia elétrica, condicionadas aos seus projetos. Este trabalho tem como objetivos representar, por meio de modelos matemáticos, os principais componentes que constituem o circuito de vapor de uma planta de geração termelétrica a vapor, com foco em caldeira aquatubular, e apresentar uma avaliação dos diversos modelos encontrados na literatura de referência, visando dar suporte ao desenvolvimento de aplicações de simulação dinâmica. Os modelos apresentados abrangem a conversão da energia térmica em energia mecânica e a conversão da energia mecânica em energia elétrica. O conhecimento das características das respostas dinâmicas dos componentes de uma central termelétrica é importante para a análise de estabilidade e para o projeto do sistema de controle. A partir dos modelos dinâmicos do processo é possível a realização de testes de estratégias de controle que, interagindo com os modelos da planta, possibilitem identificar previamente o comportamento dinâmico esperado. Este trabalho também pode ser utilizado como uma referência básica para o desenvolvimento de um simulador com finalidade de treinamento de operadores, cuja aplicação possibilita que seja feita a integração total do operador aos procedimentos operacionais, antes mesmo da partida da planta, ampliando a sua capacidade de aprendizagem
Steam power plants are able to utilize biomass and make the recovering of agricultural residues, urban residues or industrial by-products to produce electric energy, conditioned to its projects. This work aims to represent by means of mathematic modeling the main components that constitute the main steam circuit of a steam power plant, with focus in drum boiler, and to present an analysis of the several models founded at the reference literature, aiming to give support to the development of dynamic simulation applications. The models embrace the conversion of thermal energy in mechanical energy and the conversion of mechanical energy in electric energy. The knowledge of the dynamic response characteristics of power plant components is important for the analysis of stability and control system design. From the dynamic model of process is possible to perform tests of control strategies that, having interaction with the plant models, allow the previous indentifying of its hoped dynamic behavior. This work may be used also as a basic reference to the development of a simulator for operators training purpose, whose application allows the operator to be fully integrated to the operational procedures, before the plant start up, increasing his learning ability

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López, Del Prá Claudia. "A THEORETICAL INVESTIGATION OF AEROSOL RETENTION WITHIN THE SECONDARY SIDE OF A STEAM GENERATOR UNDER A SGTR SEVERE ACCIDENT SEQUENCE IN A PWR NUCLEAR POWER PLANT." Doctoral thesis, Universitat Politècnica de València, 2012. http://hdl.handle.net/10251/15183.

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Las secuencias de accidente con rotura de tubos en el generador de vapor (secuencias SGTR) están consideradas como contribuyentes del riesgo en reactores de agua a presión. Su relevancia radica en la potencial liberación de aerosoles radioactivos al medio ambiente en caso de accidente severo. Sin embargo, dichas partículas podrían quedar retenidas parcial o totalmente sobre las superficies del generador de vapor, incluso en condiciones extremas de ausencia de agua en el generador de vapor. La carencia de conocimiento en cuanto a la capacidad de retención de término fuente de este componente ha eludido su consideración en los estudios probabilistas de seguridad y en las guías de gestión de accidente severo. Esta tesis es una contribución a la comprensión y cuantificación de los procesos naturales de mitigación que tienen lugar dentro del generador de vapor como consecuencia de los accidentes SGTR. La principal actividad llevada a cabo ha sido el desarrollo de un modelo teórico que calcula la capacidad de retención de aerosoles en la etapa de rotura de un generador de vapor seco. El modelo, llamado ARI3SG, está basado en una aproximación de filtro y tiene una naturaleza semi-empírica. En él se tienen en cuenta tanto la dinámica de aerosoles como la hidrodinámica de aerosoles que tiene lugar dentro del generador de vapor en este tipo de escenarios. Para esto último, se han llevado a cabo una serie de simulaciones con el código tridimensional FLUENT 6.2, que han sido validadas con datos experimentales. El comportamiento del modelo ha sido evaluado en profundidad: primero, a través de un proceso de verificación con el que se ha visto que es robusto. Segundo, a través de un proceso de validación frente a los datos experimentales disponibles. Tercero, a través del estudio del efecto de las incertidumbres del escenario y del modelo sobre los resultados. La comparación frente a los datos experimentales ha sido satisfactoria y muestra la viabilidad del uso de formulaciones como la de ARI3SG en códigos de sistema.
López Del Prá, C. (2012). A THEORETICAL INVESTIGATION OF AEROSOL RETENTION WITHIN THE SECONDARY SIDE OF A STEAM GENERATOR UNDER A SGTR SEVERE ACCIDENT SEQUENCE IN A PWR NUCLEAR POWER PLANT [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/15183
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Dissertations / Theses on the topic 'Steam power plants'

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