Exergy Analysis of a Subcritical Reheat Steam Power Plant with Regression Modeling and Optimization (original) (raw)
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Energy and Exergy Analysis of a 348.5 MW Steam Power Plant
Energy Sources, Part A: Recovery, Utilization, And Environmental Effects, 2010
In the present work, the energy and exergy analysis of Kostolac power plant in Serbia is presented. The primary objectives of this article are to analyze the system components separately and to identify and quantify the sites having the largest energy and exergy losses. The energy and exergy efficiency is calculated using the plant operating data from the plant at different loads. The load variation is studied with the data at 100% and 60% of full load. Moreover, the effects of the load variations are calculated in order to obtain a good insight into this analysis. The performance of the plant is estimated by a component-wise modeling, and a detailed break-up of energy and exergy losses for the considered plant has been presented. The results show that energy losses have mainly occurred in the condenser where 421 MW is lost to the environment while only 105.78 MW has been lost from the boiler. Nevertheless, the irreversibility rate of the boiler is higher than the irreversibility rates of the other components. The percentage ratio of the exergy destruction to the total exergy destruction was found to be maximum in the boiler system (88.2%) followed by the turbines (9.5%), and then the forced draft fan condenser (0.5%). In addition, the calculated thermal efficiency based on the lower heating value of fuel was 39% while the exergy efficiency of the power cycle was 35.77%.
Applied Thermal Engineering, 2019
• A mathematical model is developed to analyze the exergy of steam power plant. • An exergy analysis was used to determine the devices that have the highest and lowest exergy destruction. • Different parameters and their effects on power saving and second law efficiency were studied. • Two different operation modes (full and half loads) were examined. A R T I C L E I N F O Keywords: Exergy analysis Exergy destruction Second law efficiency Thermal power plant Power saving A B S T R A C T This paper presents the exergy analysis for a 650 MW thermal power plant. The relationship between power plant exergy and thermal efficiencies is being presented for two different loads. Moreover, the effect of the decreasing condenser pressure, IPT inlet pressure and increasing S/H steam temperature inlet to both HPT and IPT is studied. The exergy analysis shows that the maximum source of exergy destruction is the boiler, followed by the turbine, then the condenser. Also, it is found that 0.5725% of the power can be saved at full load and by 0.5878% at half load if the condenser pressure is decreased from 0.067 bar to 0.049. Decreasing IPT inlet pressure by 4.5 bar will save power by 0.709% at full load and 1.394% at half load. When S/H steam temperature inlets to HPT are increased by 45 °C. The power is saved by 10.383% and 8.906% at full load and half load respectively. Also, increasing S/H steam temperature inlets to IPT by 45 °C will save power by 7.285% at full load, compared with 6.736% at half load. Moreover, increasing both inlets to HPT and IPT by 45 °C will save power by 17.67% and 15.64% at full and half loads.
Thermal Performance Analysis Of Steam Power Plant Based On Exergy Criteria
International Journal of Scientific & Technology Research, 2020
Based on the basic theory of thermal equilibrium analysis, the equivalent heat drop method is used to summarize simple and effective algorithms for the equivalent heat drop of extraction steam at all levels. In this paper, exergy analysis method is theoretically studied and modeled, and the exergy matrix equation is established. The exergy analysis method based on the second law of thermodynamics is studied and modeled, and the exergy matrix equation is derived. The main contents include: the overall analysis and partial quantitative analysis of the thermal system of the unit from the perspective of thermal equilibrium analysis, the exergy analysis of the thermal system under variable operating conditions from the perspective of exergy analysis, to find out the system's defects and deficiencies. Analyze the exergy loss distribution rules and causes of thermal systems, find the weak links in the system, and make scientific explanations for various calculation indicators.
. 21-31 Steam Condenser Exergy Analysis of Steam Power Plant at Different Loads
NORTH AMERICAN ACADEMIC RESEARCH (NAAR) JOURNAL, 2021
This paper presents steam condenser exergy analysis of 50 MW unit of the power plant by varying the ambient temperature from 5 C to 42 C at different loads. The performance parameters and the dependent variables are the exergy entering in the condenser, exergy out from the condenser, exergy efficiency of the plant, exergy destruction in the condenser and the exergy efficiency of condenser. Whereas the independent variables are ambient temperature and condenser pressure. It was seen that increases of exergy efficiency of the plant depends on combined effect of ambient temperature and condenser pressure as the sole variation of ambient temperature doesn’t have much effect on the performance parameters. The varying of ambient temperature without altering the condenser pressure doesn’t have any significant impact but by varying simultaneously the ambient temperature along with the changing of condenser pressure has profound effect on the performance parameters. As the Condenser pressure increases the heat loss is also increasing which shows the major portion of energy loss occurs in condenser. In comparison of heat loss in condenser the exergy destruction in condenser is very less. At the optimal condenser pressure 0.00804 MPa the exergy efficiency of the whole unit, exergy destruction in condenser, exergy efficiency of condenser, Heat loss (Q) in condenser and Wtotal are as 26.26%, 198.1KW, 99.72%, 81190 KW and 53.4 MW respectively and the optimal condition is attained at the full load(100%) or designed operating parameters.
In this statistical exergy study of a conventional power plant, the concept of statistical exergy analysis as an alternative to common engineering approaches is examined. The statistical aspect is drawn from conducting Analysis of Variance (ANOVA) factorial design on the components of a proposed system. The exergy aspect comes in the extension of the typical energy analysis on engineering systems to include the limitations on the system imposed by the second law of thermodynamics. To test this approach, a steam power plant discussed in an example exercise in Cengel and Boles’ 5th Edition Thermodynamics textbook was used as the subject of analysis. Effects of three input parameters on 13 responses were closely examined. While using only 8 data points, the analysis still showed highly reliable and predictable results with square of residuals (R2) values of almost 100%. Predicted R2 values ranged between 88% and 99% with one outlier of 14.36%, depending on the input parameters. Derived from the results, a new plant design concept was proposed and analyzed. This design eliminated all theoretically unnecessary drivers of exergy destruction in the plant. It also utilized the force of gravity to achieve the desired power output. The design showed an increase of 3.85% to 18% in kilowatts of work output and 5% to 7% in first and second law efficiencies. In this case, the derived design was shown to be impractical due to difficult maintenance as well as the difficulty in reaching the required pressures without a pump. However, this method of statistical exergy analysis is still valuable, as practicality of application will vary from one proposed system to another.
Computer -Aided Evaluation of Steam Power Plants Performance Based on Energy and Exergy Analysis
This paper aims to solve the power consumption problem by analysing the steam power plants from the energetic and exergetic viewpoint using computer application method. Most of the previous applications havesome specificitieswhich cannot be applied to anysteam power plant.Moreover, they neglect the volumetric analysis of the hydrocarbon fuel which has a considerable effect on the boiler and power plant efficiencies. So, the first author built a new computer program called Energy and Exergy Analyses (EEA) Whichcovers the shortage and overcomes the problems of the previous programs. We used it to analyse the increment problem of the fuel consumption occurred in the Cairo West Thermal Power Plant (Units 7 & 8). The results presented by EEA show that the boiler is the main source of exergy destruction due to combustion, boiling and superheating processes.Finally, we recommended some modifications to increase the power plant efficiency.
Energy and Exergy Analysis of a Steam Power Plant at Part Load Conditions
Port-Said Engineering Research Journal, 2017
A steam power plant can run at off-design due to change of ambient conditions or load demand. This needs to study how part-load affects the power plant performance. In this paper, the results of energy and exergy analysis carried out on a 65 MW Derna steam power plant in Libya at part load conditions are presented. The article aims to identify the magnitude, location and source of thermodynamic inefficiencies in the steam power plant at part loads. The performance of the plant was estimated by a component-wise modeling and a detailed break-up of energy and exergy losses for the considered power plant. The required outputs (power, heat and exergy destruction) of the various components and for the whole plant were assessed and calculated using mass, energy and exergy balance equations of the developed model. Based on this model, a computer program was written and used to investigate the performance of the power plant. According to the results, for full and part loads, the largest amount of energy loss occurs in the condenser and the least occurs in the boiler. In terms of exergy, the major exergy destruction was found to be maximum in the boiler, followed by the turbine, and then the condenser. The results revealed remarkable dependency of overall energy and exergy efficiencies, total exergy destruction ratio, heat rate and specific fuel consumption on the change in the load of the power plant. In conclusion, the results show how energy and exergy have been used to locate places of inefficiencies in the power plant operating at different loads.
ENERGY AND EXERGY ANALYSIS FOR PERFORMANCE IMPROVEMENT OF COAL FIRED THERMAL POWER PLANT
Steadily growing demand of power and heavily dependence on conventional sources like coal and gas for power generation has made it imperative to utilize these resources efficiently and economically. The conventional steam power plant designs are normally based on the energetic performance of plant components viz. boiler, turbine etc. First law based energetic performance analysis is not sufficient to know about the complete utilization of energy as it does not provide any information regarding quality degradation during transformation process. In this research paper concept of exergetic performance analysis i.e. application of first and second law of thermodynamics together, has been utilized to identity the location/components where major energy and exergy losses takes place and also to determine the extent of losses. In the present study complete first and second law analysis of a 250MW coal fired thermal power plant at Korba, Chhattisgarh, India, is carried out at three different loads. The energy and exergy efficiency of the components have been determined. The energy efficiency of the plant is found to be 38.5%, 37.54% and 34.63% respectively for the plant operation at 250MW, 200MW and 125MW. A similar trend is seen in exergetic performance and exergy efficiency is recorded as 36.32%, 34.41% and 32.67% respectively at three loads mentioned above. It is observed that at the full load of 250MW the maximum energy loss (46.26% of the input) among all the components is taking place in the condenser which is the 72.46% of total energy loss whereas the maximum exergy loss of around 50% of the input takes place in the boiler and this contributes to 76.67% of total exergy loss. Both on the basis of quantity and percent exergy loss, boiler is the key component showing huge potential for saving. This study suggests that the possible measures should be taken to avoid the quality degradation of energy in boiler i.e. in the zone of higher temperature gradient and operation of the plant closed to the full load should be ensured for better performance.
Energy and Exergy Analysis of a Coal Fired Power Plant
October 2018, 2018
In this paper, energy and exergy analysis has been conducted on a subcritical coal fired power plant of Wisconsin Power and Light Company, USA to investigate the steam cycle energy and exergy efficiency. The cycle is analyzed by developing a mathematical model using its operating and design parameters. The analysis is performed using EES (Engineering Equation Solver). The energy analysis shows that major share of energy loss occurs in condenser i.e. 72% of total cycle energy loss, whereas, exergy analysis shows that 83.09% total exergy destruction of cycle occurs in boiler.Furthermore, the simulation results are compared with actual with an absolute error of 3.1%. Additionally, the parametric study is performed to examine the effects of various operating parameters such as main steam pressure and temperature, condenser pressure, terminal and drain cooler temperature difference on net power output, energy andexergy efficiency of cycle. The parametric study shows that the plant has ma...
Thermoeconomic Analysis with Regression Modelling and Optimization of Steam Coal Power Plant
NORTH AMERICAN ACADEMIC RESEARCH (NAAR) JOURNAL 2021, VOLUME 4, ISSUE 3, PAGES 01-13 https://doi.org/10.5281/zenodo.4575426 , 2021
In this study, exergy and economic analyses with regression of a 50 MW unit of Lakhra steam power plant, situated near Jamshoro Pakistan is presented. Firstly, a thermodynamic model is developed using Engineering Equation Solver (EES) software and validated, followed by an economic assessment parametric analysis to show the impacts of various operating parameters on the levelized cost and finally regression along with optimization is carried out. The condenser pressure, main steam pressure, temperature and interest rate are selected as operating parameters while levelized cost, net power output, energy and exergy efficiencies are selected as performance parameters. Furthermore, in order to know about the effects of predictor and response variables with each other and to correlate the performance parameters with the operating parameters the multiple polynomial regression analysis has been prepared. In economic analysis, levelized cost of electricity is estimated under various operating and economic conditions. Under designed parameters, the plant is simulated yielding 53.5 MW power output with 31.02% and 26.24% energy and exergy efficiencies, respectively with levelized cost of US$0.0654/kWh. According to the optimization results, maximum power, energy and exergy efficiencies are obtained as 53.786 MW, 31.25% and 26.43%, respectively, whereas minimum levelized cost is obtained as US$0.04856/kWh under given optimal conditions.