This master thesis deals with the performance calculations of a 9MW linear Fresnel CSP plant withdirect steam generation built by the Solar Division of the CNIM Company. The aim was to calculate theannual electricity production taking into account the weather conditions as well as some steam storage.At first, a steam accumulator model was developed with Excel, in order to estimate the pressureevolution in the tanks during the charging, storage and discharging processes. The data obtained withthis model was then integrated to the thermodynamic cycle model, programmed with Excel, whichcalculated the electrical power production knowing the thermal power available in the solar field. Theelectricity production calculations were made every 600 seconds during one year.To improve the results accuracy, the influence of the plant location slope was estimated, calculating theequivalent azimuth and elevation angles in a new spherical coordinates system. For an average slope of4.21° at the plant location, the annual thermal energy gain is 14.4% (with a gain up to 60% duringwinter days) and the annual electricity production is increased by 12.59%. The influence of frost on themirrors during cold and humid nights was also estimated with a simple model of the energy needed toheat up a constant layer of ice. Depending on the assumptions, the electricity production losses werebetween 1.27 and 2.84% of annual electricity production. The losses due to plant shutdowns set by theelectrical network manager RTE during the snowmelt months were also estimated. The annualelectricity production could decrease by 8.02 to 11.57 % because of the load management, dependingon the days during which the plant is shutdown.Finally, an economic optimisation was led with prices estimated by CNIM, which gave an optimal solarfield design with 31 lines and 5 steam accumulators. The payback time would then be 9.887 years.

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

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

Abstract Recently, the expansion in power system capacities leads to the development of large-scale steam turbine generator units. As a result, a fault on the power system may induce large fault current and give rise to serious torque vibrations on turbine shafts and blades, which ought to be improved in order for the reliable operation of a turbine-generator system. In the thesis, countermeasures are proposed from electrical viewing-point and from mechanical viewing-point respectively. Based on electrical viewing-point, the apparatus in the generator stator side and in the rotor side respectively is applied to suppress the induced disturbing source. The high temperature superconductive fault current limiter bank introduces a large normal-state resistance to restrict the dc component of stator fault current. The choke coil acts as a low pass filter to restrict the system-frequency component of field fault current. Both of them lead to the reduction in electromagnetic torque of system-frequency and effectively improve the vibrating behavior of blades. Based on mechanical viewing-point, it is found from the electromechanical analysis that the Generator/LP-Turbine shaft stiffness and the Generator rotor inertia constant determine the responses of all turbine blades. Once the stiffness on this shaft section is reduced by replacing the rigid shaft coupling with a flexible one or the inertia constant is augmented by a system-frequency mechanical filter, the blades become intrinsically less responsive to electrical disturbances. As a result, the blades will bear less stress impact and can be designed with smaller safety factor. On the other hand, LP-turbine long blades operated in corrosive environment and underwent the statistical stress impact due to randomly distributed negative sequence current is studied also. In such situation, the blades may be subjected to corrosion fatigue and the long term effects of power system unbalance may become the cause of fatigue damage on blades though the negative sequence current is still within the limitation of generator thermo-rating. As a result, turbine blades are possibly unprotected by traditional system unbalance protection scheme. Therefore, it will depend on the operating environments and the blade materials whether such long-term stress can be neglected or not. If there is the potential of blade damage, one has to reconsider the I2 protection settings and rearrange the load distribution to limit the system unbalance.

Thermische Gehäuseverkrümmungen spielen bei der Dimensionierung von radialen Spielen in Industriedampfturbinen eine große Rolle. Die zuverlässige Vorausberechnung der Gehäuseverkrümmung ist wichtig, um einerseits möglichst kleine Spiele und damit hohe innere Wirkungsgrade erzielen zu können und andererseits Schäden in Folge von Spielüberbrückungen auszuschließen. In der vorliegenden Arbeit wurde die Gehäuseverkrümmung mit analytischen Methoden und mit Hilfe von 3D-FE-Analysen untersucht. Eine neue semi-analytische Berechnungsmethode auf Basis eines Stufenkörpermodells wurde entwickelt. Damit lassen sich komplexe Geometrien und unterschiedliche thermische Randbedingungen berücksichtigen. Der Einfluss von Rotationsasymmetrien auf die Verkrümmung wurde mit Hilfe einer FE-Parameterstudie untersucht und in Form von Einflussfaktoren in das Modell integriert. Im Vergleich zu vereinfachten FE-Modellen und zu gemessenen Verkrümmungen an realen Turbinengehäusen zeigt das semi-analytische Modell eine gute Übereinstimmung. Weiterhin wurde das Verkrümmungsverhalten von Industriedampfturbinengehäusen mit Hilfe von 3D-FE-Analysen untersucht. Durch Abgleich von gemessenen und simulierten Temperaturen und Verformungen konnten Erkenntnisse zum Modellaufbau gesammelt werden. Da die thermischen Randbedingungen bei der Simulation von Gehäuseverkrümmungen von größter Bedeutung sind und Defizite beim Wissensstand zum Wärmeübergang erkannt wurden, sind umfangreiche Messungen des Wärmeübergangskoeffizienten durchgeführt worden. Damit wurde ein Beitrag geleistet, FE-Analysen zukünftig auch bei Dimensionierungs- und Auslegungsfragen einsetzen zu können.

Lors de sa détente dans une turbine, la vapeur subit une chute d’enthalpie qui entraîne sa condensation spontanée sous forme d’un nuage de gouttelettes submicroniques. Ces gouttes vont se déposer sur les aubes aval et y former un film d’eau. Ce dernier est arraché sous l’effet de l’écoulement de vapeur environnant ce qui crée des gouttes de quelques dizaines de microns qui peuvent se redéposer sur les aubes aval. Ces phénomènes sont à l’origine de pertes, généralement regroupées sous le terme générique de ”pertes par humidité”, estimées grâce à la loi de Baumann. Le but de cette thèse est de mettre en place dans un code méridien des modèles permettant la prise en compte des phénomènes de condensation, de déposition et d’écoulement des films liquides afin de pouvoir estimer les pertes liées à chacun d’entre eux. Dans cette optique un modèle diphasique homogène permettant d’avoir accès à la fraction massique de liquide et au nombre de gouttes est implanté dans le code méridien. Ce modèle est validé sur un cas test expérimental de détente en tuyère et alimente le modèle de déposition. Les contributions de la diffusion, de la turbophorèse, de la thermophorèse, de la gravité et de l’inertie des gouttes à la déposition sont étudiées. Il apparaît nécessaire de prendre en compte la diffusion, la turbophorèse et la déposition inertielle sur les bords d’attaque des aubes. Un modèle permettant d’avoir accès à l’épaisseur et à la vitesse d’un film liquide soumis au cisaillement d’un écoulement environnant, à la force de frottement sur la paroi et aux effets de la rotation est mis en place. Ce modèle est validé par rapport à des résultats expérimentaux d’écoulement de film liquide sur une plaque plane dans des conditions proches de celles rencontrées en turbine à vapeur basse pression. Finalement, un calcul réalisé sur une géométrie réelle de turbine basse pression de 8 étages permet de démontrer l’applicabilité de la méthodologie mise en place sur un cas industriel. Les contributions des phénomènes étudiés aux pertes par humidité sont explicitées. / During the expansion in a turbine, the enthalpy of the steam fall. This fall leads the steam to cross the saturation line and brings about its spontaneous condensation and the appearance of fog droplets. The deposition of these droplets on downstream blades lies at the root of the creation of a liquid film. This film is torn off by steam flow and creates coarse water. These big droplets can impact downstream blades. Each of these phenomena induces some losses which are generally grouped in the ”wetness losses” estimated thanks to Baumann’s rule. The aim of this work is to develop, in a throughflow code, some models which allow to take into account the condensation, deposition and liquid film flow and the losses linked to each of these phenomena. An homogeneous two phases flow model is implemented in the throughflow code. Two transport equations on the mass fraction of liquid and on the droplets number are added to Euler’s equations written for gas phase. This model is validated on an experimental test case of expansion in nozzle and feeds the model of deposition. The influences of diffusion, turbophoresis, thermophoresis, gravity and of inertia of droplets on the deposition are studied. It appears to be necessary to take into account diffusion, turbophoresisand deposition due to inertia on the leading edges of blades. A model which allows to evaluate the thickness and the velocity of a liquid film submitted to aerodynamic shear, friction on blades and rotational effects has been developed. This model is validated on experimental results of a liquid film flow on a flat plate in some conditions representatives of those encountered in low pressure steam turbines. Finally a calculation realised on a real geometry of a 8-stages low pressure steam turbine has demonstrated that the methodology developed during this work can be used on an industrial test case. The contributions of the phenomena studied to wetness losses are evaluated.

Content of this thesis is design of one-housing condensing steam turbine with two uncontrolled extractions. First part is describing design of balance scheme. Including cycle joints calculation, design of equipment for whole steam and condense cycle. Thesis continues with preliminary and detail design of regulativ stage. Main goal of this part is thermodynamic calculation of flow channel. Second part is describing lubricating oil and cooling system. Contains process description of lubricating oil scheme including calculation, specification of components and pipe branches design. Diploma thesis is finished with detail lubricating oil scheme.

Diploma thesis named CFD simulation of the steam flow in the unregulated extraction of the steam turbine is about an analysis of the balance piston impact on the area of the steam turbine, where the extraction is located. First part describes basic knowledge of the steam turbine in general. At the end of this chapter, there is a description of the solved steam turbine. Next chapter is about introduction to the CFD. Practical part deals with a construction of 3D models, meshing and setting of the boundary conditions in the program ANSYS CFX. The main part of this thesis summarizes the results of the CFD simulation and stipulates the temperature range on the extraction pipe. In conclusion, there is a recommendation how to determine design temperature of the extraction pipe influenced by the balance piston.

The topic of thesis is condensing turbine in gas-steam cycle, which can be divided into four basic parts. A history of gas-steam cycle is described in the beginning. Second part is all about calculation of heat recovery steam generator. Penultimate section deals with calculations of steam turbine parameters and reaction blading type. Last part contains electric power and steam turbine efficiency.

This thesis discusses the reconstruction of the turbogenerator TG5 of the Elektrárny Opatovice and introduces options of technical solutions for power central of combined heat and electricity production. First section describes the differences between back-pressure and condensing turbines. Next section briefly introduces the company Elektrárny Opatovice a.s. with the description of the current back-pressure turbine TG5, which is near end of it life cycle and is to be reconstructed in following years. Based on the technical-economic analysis of the operation of the current TG5, possible benefits of new technical solutions are proposed.