<p>På överhettartuber i värmepannor bildas beläggningar på grund av sot och partiklar från förbränningen. Beläggningarna isolerar överhettartuberna vilket försämrar värmepannans verkningsgrad. Sotning av tuberna sker under drift och ett system som automatiskt kan beräkna hur mycket beläggningar som finns på tuberna skulle kunna göra sotningen mer behovsstyrd.Resonansfrekvenser hos överhettartuberna påverkas av masspåslaget som blir när beläggningar bildas. En förändring i frekvens kan då översättas till en förändring i massa. Vibrationsmätningar har gjorts med töjningsgivare som är monterade på överhettartuber i en av Ryaverkets pannor och i SAKAB:s panna. I detta examensarbete har syftet varit att analysera olika metoder för att skatta resonansfrekvenser i genomförda mätningar. Algoritmerna MUSIC, ESPRIT och AR samt en heuristisk statistisk metod har testats på genererade signaler. MUSIC och ESPRIT har givit bäst skattningar och har därefter använts för att analysera mätningarna. Periodvis följer vissa skattningar av mätningar från Ryaverket trender mellan sotningarna vilket indikerar att det skulle kunna vara resonansfrekvenser. Annars innehåller skattningarna för mycket variationer. Skattningarna av mätningar från SAKAB:s panna är gjorda under en kortare tidsperiod men visar en tydligare trend som troliggör att det är resonansfrekvenser som detekterats.För att automatiskt hitta och följa resonansfrekvenser i skattningarna, även om dessa innehåller stora variationer, har en målföljningsalgoritm implementerats. Algoritmen hittar skattningar som följer en förväntad trend mellan sotningarna. Tester visar att algoritmen hittar troliga resonansfrekvenser i skattningarna men att det är svårt att kunna dra några slutsatser om skattningarna varierar för mycket. Bättre signaler skulle kunna minska variationerna hos skattningarna. Ett förslag presenteras hur MUSIC eller ESPRIT tillsammans med en målföljningsalgoritm skulle kunna användas för att beräkna masspåslag på överhettartuberna.</p> / <p>Combustion in thermal power plants emits particles which create coatings on the super heater tubes. The coatings insulate the tubes and impairs the efficiency of the heat transfer. Cleaning the tubes occurs while the power plant is running and a system that automatically calculates the amount of coatings could make the cleaning more needs-based. The resonance frequencies of the super heater tubes are affected by the added mass of the coatings. A change in frequency corresponds to a change in mass. Vibration measurements have been made with strain gauges on the super heater tubes in Ryaverket's power plant and in one of SAKAB's power plants. The purpose of this thesis work has been to analyse different methods to estimate resonance frequencies in the vibration measurements. ESPRIT, MUSIC, AR and a heuristic statistical method have been tested on generated signals. MUSIC and ESPRIT have given the best estimations and have thus been used to analyse the measurements. Periodically some estimations of measurements from Ryaverket are following trends which indicates that they could be resonance frequencies. The rest of the estimations contain too large variations. The estimations made of the measurements from SAKAB have been made during a shorter time period but shows clearer trends which make them probable resonance frequencies.To automatically trace resonance frequencies in the estimations, even though they contains large variations, a target tracking algorithm has been implemented. The algorithm finds estimations that follows expected trends between the cleaning periods. Tests shows that the target tracking algorithm finds probable resonance frequencies in the estimations but that it is hard to reach a conclusion if they contain large variations. Better measurements could give estimations with smaller variations.An idea is presented where MUSIC or ESPRIT together with a target tracking algorithm could be used to calculate the amount of coatings on the super heater tubes.</p>

På överhettartuber i värmepannor bildas beläggningar på grund av sot och partiklar från förbränningen. Beläggningarna isolerar överhettartuberna vilket försämrar värmepannans verkningsgrad. Sotning av tuberna sker under drift och ett system som automatiskt kan beräkna hur mycket beläggningar som finns på tuberna skulle kunna göra sotningen mer behovsstyrd.Resonansfrekvenser hos överhettartuberna påverkas av masspåslaget som blir när beläggningar bildas. En förändring i frekvens kan då översättas till en förändring i massa. Vibrationsmätningar har gjorts med töjningsgivare som är monterade på överhettartuber i en av Ryaverkets pannor och i SAKAB:s panna. I detta examensarbete har syftet varit att analysera olika metoder för att skatta resonansfrekvenser i genomförda mätningar. Algoritmerna MUSIC, ESPRIT och AR samt en heuristisk statistisk metod har testats på genererade signaler. MUSIC och ESPRIT har givit bäst skattningar och har därefter använts för att analysera mätningarna. Periodvis följer vissa skattningar av mätningar från Ryaverket trender mellan sotningarna vilket indikerar att det skulle kunna vara resonansfrekvenser. Annars innehåller skattningarna för mycket variationer. Skattningarna av mätningar från SAKAB:s panna är gjorda under en kortare tidsperiod men visar en tydligare trend som troliggör att det är resonansfrekvenser som detekterats.För att automatiskt hitta och följa resonansfrekvenser i skattningarna, även om dessa innehåller stora variationer, har en målföljningsalgoritm implementerats. Algoritmen hittar skattningar som följer en förväntad trend mellan sotningarna. Tester visar att algoritmen hittar troliga resonansfrekvenser i skattningarna men att det är svårt att kunna dra några slutsatser om skattningarna varierar för mycket. Bättre signaler skulle kunna minska variationerna hos skattningarna. Ett förslag presenteras hur MUSIC eller ESPRIT tillsammans med en målföljningsalgoritm skulle kunna användas för att beräkna masspåslag på överhettartuberna. / Combustion in thermal power plants emits particles which create coatings on the super heater tubes. The coatings insulate the tubes and impairs the efficiency of the heat transfer. Cleaning the tubes occurs while the power plant is running and a system that automatically calculates the amount of coatings could make the cleaning more needs-based. The resonance frequencies of the super heater tubes are affected by the added mass of the coatings. A change in frequency corresponds to a change in mass. Vibration measurements have been made with strain gauges on the super heater tubes in Ryaverket's power plant and in one of SAKAB's power plants. The purpose of this thesis work has been to analyse different methods to estimate resonance frequencies in the vibration measurements. ESPRIT, MUSIC, AR and a heuristic statistical method have been tested on generated signals. MUSIC and ESPRIT have given the best estimations and have thus been used to analyse the measurements. Periodically some estimations of measurements from Ryaverket are following trends which indicates that they could be resonance frequencies. The rest of the estimations contain too large variations. The estimations made of the measurements from SAKAB have been made during a shorter time period but shows clearer trends which make them probable resonance frequencies.To automatically trace resonance frequencies in the estimations, even though they contains large variations, a target tracking algorithm has been implemented. The algorithm finds estimations that follows expected trends between the cleaning periods. Tests shows that the target tracking algorithm finds probable resonance frequencies in the estimations but that it is hard to reach a conclusion if they contain large variations. Better measurements could give estimations with smaller variations.An idea is presented where MUSIC or ESPRIT together with a target tracking algorithm could be used to calculate the amount of coatings on the super heater tubes.

To design a grate boiler with a natural circulation for burning of a pine bark with an output 18t/h is a primary objective of this dissertation. Individual parts of a boiler and it´s heat transfering surfaces were calculated after the working out of stoichiometric calculations from given element analysis of fuel. All computations have to fulfill several parameters: boliler output, temperature and pressure of an overheated steam.

The goal of this Master’s Thesis is to design a refuse derived fuel (RDF) fired steam boiler with 70 t/h processing ability. The assignment consists of requested output parameters of overheated steam and analysis of fuel components. This analysis was used for stoichiometric calculation of fuel. Furthermore, heat balance of the boiler was calculated, from which was determined the heat loss and the efficiency of the boiler. Individual designs and calculations of heating surfaces and boiler dimensions were carried out from requested output parameters.

Orientador: Marcelino Pereira do Nascimento / Resumo: Estudos recentes mostram tendência de desenvolvimento de sistemas capazes de recuperar energia dos gases de escape. Apesar de ser de fato uma fonte de energia, os sistemas para recuperação instalados na linha de exaustão mostram grande complexidade e necessidade de muito espaço de instalação. O presente estudo demonstra a viabilidade de recuperação de energia do sistema de arrefecimento com espaço de instalação reduzido. O estudo propõe a geração de vapor através de perfis instalados nas paredes da câmara de combustão e sua aplicação em um ciclo Rankine para gerar trabalho através de expansor. A simulação realizada com o software GT-Power demonstra a possibilidade de extrair calor das câmaras com a mesma eficiência de um sistema convencional de arrefecimento por água e aditivo. Paralelamente, o estudo propõe um sistema de recirculação de gases de exaustão sem o uso de um trocador de calor, patenteado pela empresa patrocinadora, complementando a estratégia para evitar o uso desnecessário de energia em um motor a combustão. Os gases provenientes da linha de baixa pressão da exaustão são admitidos pela linha de ar limpo, em alta pressão, através do uso de uma válvula Laval. Os resultados são provenientes de uma rotina de cálculo em Excel, base VBA. O sistema permite que os gases fluam por fora da turbina e elimina a necessidade de um trocador de calor, resolvendo o maior problema dos sistema convencionais de recirculação de gases em baixa pressão. A combinação das duas soluções,... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor

The aim of the work is to design a plain wood combustion boiler of 88 t/h output. Fuelling component analysis has been added to the basic boiler parameters. For given fuel is prepared stechiometric calculations. After making the heat balance of boiler is determined the thermal efficiency. For given output of steam parametrs (temparature, pressure, volume) are designed individual convective surfaces and dimensons of the boiler. It is also made drawings.

The aim of this thesis is design a grate steam boiler for burning straw with an output of 10 tons of steam per hour. The produceds team has parameters 320 °C, 3,2 MPa. For a given fuel (fytomass) is calculated stoichiometric calculation. The following is the calculation of the heat balance of the boiler including the determinativ of thermal efficiency. The fuel used, the required parameters of steam and feed water temperature are designed individual convective surfaces and dimensions of the boiler. The boiler design includes drawings.

The work deals with the constructional and calculation design of the boiler for burning wood and combustion coal in scale (30/70-coal), in load 50 t/h, parameters of steam output p=7,5 MPa, t=480 °C and a temperature of feed water 105 °C. It is a boiler with natural water circulation by evaporation surfaces. In proposal first steichiometric calculations and enthalpic calculations of air and flue gas are performed. Then it is calculated heat balance, the boiler losses and the thermal efficiency is determined. After designing the combustion chamber and dimensions of pulls are determined. In last chapter the overall energy balance are checked. Drawing documentation of steam boiler is a part of the work.

The thesis deals with steam boiler design of 88 tons per hour capacity and with the outlet steam parameters of 9,6 MPa and 520 °C. Fuel for boiler is wood chips. The main focus of the thesis is on heat calculation, design of dimensions and layout of heat surfaces. The thesis also include drawing of steam boiler.

The thesis includes design of steam boiler burning woodchips with parameters of steam 88 t/h, 9,6 MPa, 520 °C. For these parameters is processed a heat calculation and dimensional design of boiler.