Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Miroslav M ?ivkovi?,Sne?ana D Vulovi?,Rodoljub S Vujanac
Thermal Science , 2010, DOI: tsci100507030z
Abstract: In this paper analysis of stress and thermal-elastic-plastic strain of the drum is performed. Influence of modified thickness, yield stress and finite element model of welded joint between pipe and drum on assessment of the remaining lifetime of the drum in the thermal power plant is analyzed. Two analyses are compared. In the first, drum is modeled by shell and by 3D finite elements with projected geometrical and material data of drum. Then, the drum is modeled by shell and by 3D finite elements with modified thickness and yield stress. The analysis show that detailed modeling of stress concentration zones is necessary. Adequate modeling gives lower maximal effective plastic strain and increased number of cycles and, in that case, 3D finite elements are better comparing to shell finite elements.
Modified Method for Reliability Evaluation of Condensation Thermal Electric Power Plant
Journal of Safety Engineering , 2012, DOI: 10.5923/j.safety.20120104.02
Abstract: Present methods for forecasting and evaluation of thermal power plants reliability were based on appliance of statistics and probability calculation related to strength and in the same time leaning on modern methods for deterministic project-constructive calculations of elements, subsystems and systems. Applying the advantages of modern directions in system reengineering and structural or RCM (Reliability Centered Maintenance) way of using the best methods in reliability analysis of complex systems, the block diagram of modified method for basis referential 300 MW block has been created. As a starting database, the results of research of basic configurations of thermal power plants for solid fuel Ugljevik and Gacko with nominal referential power of 300 MW were used. For other facilities inside thermal power plants witch nominal power differs from 300 MW, recalculation of reliability indicators has to be carried out. Whereat the simple empirical relation in dependence of previously determined reliability indicator for 300 MW system is used so as the exponent determined on basis of statistical data processing from the exploitation during the lifespan of the power plant. The method is of the iterative nature and is about to be terminated as the starting hypothesis related to matching of results of the forecasting and real exploitation results affirms. The research related for suggested modified method gave several relatively new results which are presented inside the paper. The result represents the algorithm of modified method for evaluation of reliability of referential thermal power plant system and its modification aiming to include thermal power plants of other nominal powers.
Ravinder Kumar,A k Sharma,P C Tewari
International Journal of Engineering Science and Technology , 2011,
Abstract: This paper discusses the performance analysis of the furnace draft air cycle in a thermal power plant. The furnace draft air cycle in a thermal power plant has three main subsystems. These subsystems are arranged in series and parallel configurations. For the analysis of availability, formulation of the problem is carried out using Markovbirth-death process based upon probabilistic approach. Failure and repair rates for all the subsystems are considered to be constant. A transition diagram representing interrelationship among the full working, reduced capacity and failed states has been developed. The effect of failure and repair parameters of each subsystem on the system availability has been determined. The results are supplied to the management, which will help to improve the overall performance of the thermal power plant concerned.
Pilot Solar Thermal Power Plant Station in Southwest Louisiana  [cached]
Terrence Chambers,Jonathan R Raush,G.H. Massiha
International Journal of Applied Power Engineering , 2012, DOI: 10.11591/ijape.v2i1.1941
Abstract: Solar thermal plants are basically power plants that generate electricity from high-temperature heat. The difference between them and conventional power plants is that instead of deriving energy from gas, coal or oil, the sun provides the energy that drives the turbines. In this paper we will give a brief demonstration of solar thermal power and different system designs of solar thermal power plants. Then we will see the feasibility of implementing solar power plants in Louisiana which currently depends mostly on its conventional power plants which use traditional fuels such as gas, oil, and coal. This study was a part of a proposal that was funded by the US the Department of Energy to construct solar thermal plant near Lafayette, Louisiana. The power plant is currently under the construction and it will be completed by Summer of 2013.
The Optimal Steam Pressure of Thermal Power Plant in a Given Load  [PDF]
Yong Hu, Ji-zhen Liu, De-liang Zeng, Wei Wang, Ya-zhe Li
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.54B054
Abstract: As the large change of the grid load, many large capacity units of our country had to change the load in order to meet the gird need. When a thermal power plant receives a given load instruction from the grid, it is necessary to set an optimal steam pressure to maintain the high efficiency of the plant. In the past optimization methods, during the process of calculation, the output of the turbine often changed, it was hard to maintain the output constant. Therefore, in combination with the theory of variable condition of turbine, calculation of governing stage and the matrix equation of thermal power system, an optimization method were put forward and an optimal solution was got in a given load.
Improvement of environmental aspects of thermal power plant operation by advanced control concepts  [PDF]
Mikulandri? Robert,Lon?ar Dra?en,Cvetinovi? Dejan,Spiridon Gabriel
Thermal Science , 2012, DOI: 10.2298/tsci120510134m
Abstract: The necessity of the reduction of greenhouse gas emissions, as formulated in the Kyoto Protocol, imposes the need for improving environmental aspects of existing thermal power plants operation. Improvements can be reached either by efficiency increment or by implementation of emission reduction measures. Investments in refurbishment of existing plant components or in plant upgrading by flue gas desulphurization, by primary and secondary measures of nitrogen oxides reduction, or by biomass co-firing, are usually accompanied by modernisation of thermal power plant instrumentation and control system including sensors, equipment diagnostics and advanced controls. Impact of advanced control solutions implementation depends on technical characteristics and status of existing instrumentation and control systems as well as on design characteristics and actual conditions of installed plant components. Evaluation of adequacy of implementation of advanced control concepts is especially important in Western Balkan region where thermal power plants portfolio is rather diversified in terms of size, type and commissioning year and where generally poor maintenance and lack of investments in power generation sector resulted in high greenhouse gases emissions and low efficiency of plants in operation. This paper is intended to present possibilities of implementation of advanced control concepts, and particularly those based on artificial intelligence, in selected thermal power plants in order to increase plant efficiency and to lower pollutants emissions and to comply with environmental quality standards prescribed in large combustion plant directive. [Acknowledgements. This paper has been created within WBalkICT - Supporting Common RTD actions in WBCs for developing Low Cost and Low Risk ICT based solutions for TPPs Energy Efficiency increasing, SEE-ERA.NET plus project in cooperation among partners from IPA SA - Romania, University of Zagreb - Croatia and Vinca Institute from Serbia and. The project has initiated a strong scientific cooperation, with innovative approaches, high scientific level, in order to correlate in an optimal form, using ICT last generation solutions, the procedures and techniques from fossil fuels burning processes thermodynamics, mathematical modelling, modern methods of flue gases analysis, combustion control, Artificial Intelligence Systems with focus on Expert Systems category.]
Simulation modeling and analysis of a complex system of a thermal power plant  [cached]
Sorabh Gupta,Puran C. Tewari
Journal of Industrial Engineering and Management , 2009, DOI: 10.3926/jiem..v2n2.p387-406
Abstract: The present paper deals with the opportunities for the modeling of flue gas and air system of a thermal power plant by making the performance evaluation using probabilistic approach. The present system of thermal plant under study consists of four subsystems with three possible states: full working, reduced capacity working and failed. Failure and repair rates for all the subsystems are assumed to be constant. Formulation of the problem is carried out using Markov Birth-Death process using probabilistic approach and a transition diagram represents the operational behavior of the system. Interrelationship among the full working and reduced working has been developed. A probabilistic model has been developed, considering some assumptions. Data in feasible range are selected from a survey of thermal plant and the effect of each subsystem on the system availability is tabulated in the form of availability matrices, which provides various performance/availability levels for different combinations of failure and repair rates of all subsystems. Based upon various availability values obtained in availability matrices and graphs of failure/repair rates of different subsystems, performance and optimum values of failure/repair rates for maximum availability, of each subsystem is analyzed and then maintenance priorities are decided for all subsystems.
The Influence of Throughput on Thermodynamic Efficiencies of a Thermal Power Plant
International Journal of Energy Engineering , 2012, DOI: 10.5923/j.ijee.20120205.11
Abstract: This study carried out energy and exergy analyses of a thermal power plant in order to evaluate the energetic and exergetic efficiencies and irreversibilities of units, sections and the overall system. It was also, to determine the optimum fuel-air ratio and optimum combustion temperature at different throughputs. The thermal plant consisting of 23 units and 4 sections was simulated using HYSYS simulation software and EXCEL spreadsheet. The EXCEL spreadsheet was used for the energy and exergy analyses. It was found that throughput did not influence the energy efficiencies of the units but the exergy efficiencies. Throughput did not influence the energy and exergy efficiencies of the sections. The overall energetic efficiencies of the plant were 18.17, 19.79, 21.42, and 21.45% and the overall exergetic efficiencies were 10.26, 11.22, 11.58, and 11.61% for throughputs of 50, 75, 100 and 110%, respectively. The overall irreversibilities of the plant increased as the throughput increased. The optimum fuel-to-air ratio which gave the optimum combustion temperature in the furnace was found to be 1:12.6 for all the throughputs which was an improvement over the current practice of 1:19.8. Throughput did not influence the maximum combustion temperature in the furnace.
Exergy Analysis of Operating Lignite Fired Thermal Power Plant  [PDF]
T. Ganapathy,N. Alagumurthi,R. P. Gakkhar,K. Murugesan
Journal of Engineering Science and Technology Review , 2009,
Abstract: The energy assessment must be made through the energy quantity as well as the quality. But the usual energy analysisevaluates the energy generally on its quantity only. However, the exergy analysis assesses the energy on quantity as well asthe quality. The aim of the exergy analysis is to identify the magnitudes and the locations of real energy losses, in order toimprove the existing systems, processes or components. The present paper deals with an exergy analysis performed on anoperating 50MWe unit of lignite fired steam power plant at Thermal Power Station-I, Neyveli Lignite Corporation Limited,Neyveli, Tamil Nadu, India. The exergy losses occurred in the various subsystems of the plant and their components havebeen calculated using the mass, energy and exergy balance equations. The distribution of the exergy losses in several plantcomponents during the real time plant running conditions has been assessed to locate the process irreversibility. The Firstlaw efficiency (energy efficiency) and the Second law efficiency (exergy efficiency) of the plant have also been calculated.The comparison between the energy losses and the exergy losses of the individual components of the plant shows that themaximum energy losses of 39% occur in the condenser, whereas the maximum exergy losses of 42.73% occur in the combustor.The real losses of energy which has a scope for the improvement are given as maximum exergy losses that occurredin the combustor.
Modelling of Solar Thermal Power Plant Using Parabolic Trough Collector  [PDF]
Jignasha Bhutka, Jaymin Gajjar, T. Harinarayana
Journal of Power and Energy Engineering (JPEE) , 2016, DOI: 10.4236/jpee.2016.48002
Abstract: The target of the National Solar Mission is to build up India as a worldwide pioneer in solar energy generation. Solar power can be transmitted through grid either from solar photovoltaic or solar thermal technology. As compared to solar photovoltaic, solar thermal installations are less studied, especially regarding energy estimation and performance analysis. For estimating the potential of CSP plants, it is planned to simulate a power plant. We have marginally modified the design of 1 MW operational power plant installed at Gurgaon using Parabolic Trough Collector (PTC) technology. The results are compared with the expected output of Gurgaon power plant and also 50 MW power plant at Rajasthan. Our results have closely matched with a small deviation of 3.1% and 3.6% for Gurgaon and Rajasthan plants, respectively. Our developed model is also validated with 18 different solar power plants in different parts of the world by slightly modifying the parameters according to the plant capacity without changing major changes to the plant design. Difference between our results and the expected energy generation varied from 0.4% to 13.7% with an average deviation of 6.8%. As our results show less than 10% deviation as compared to the actual generation, an attempt has been made here to estimate the potential for the entire nation. For this modelling has been carried out for every grid station of 0.25° × 0.25° interval in India. Our results show that annual solar thermal power plant of 1 MWe capacity potential varies from 900 to 2700 MWh. We have also compared our results with previous studies and discussed.
Page 1 /100
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.