Thermal Performance Analysis Of Steam Power Plant Based On Exergy Criteria (original) (raw)
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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.
Effect of key parameters on thermodynamic and thermoeconomic performance of steam power plant
The first law of thermodynamics is a useful tool for thermodynamics processes analysis. The exergy analysis of a conventional steam power plant was done. This analysis is based on first and second law of thermodynamics. In the present paper, a conventional steam power plant was investigated using a thermoeconomic analysis. Having done this analysis the inefficient components of a steam power plant cycle was identified. In this analysis, it was assumed that the cycle components are adiabatic and the potential and kinetic terms of exergy were negligible. The exergy analysis combined with the economical aspects. These aspects include capital investment cost, fuel cost and operating and maintenance cost for evaluation of final cost of product. According to this calculation exergy destruction cost of each component in the cycle and their role were evaluated. Based on these results the effect of the component efficiency on the final cost of the product and performance revealed. Effect of main steam temperature, reheated temperature, condenser pressure and number of the feed water heaters on cycle performance and final electrical power cost were also determined.
Environmental Engineering Research, 2021
Exergy analysis is an important tool to identify the improvements in various industrial processes. In this study, the existing steam power plant is examined based on energy and exergy analyses. The steam network in the power plant is comprised of two sections, one of them is used for paddy drying, while other portion is used to operate the turbine for in-house electricity production. Mass, energy, and exergy balances are applied to individual equipment of the plant. The power plant is modeled and simulated using Aspen HYSYS® V10. The calculated thermodynamic values are used for in-depth analysis of the power plant. Case-studies are included in this study to show the effect of various operational parameters on the process efficiency. The analysis shows that the boiler is the major source of exergy destruction, because of the incomplete combustion process, and inappropriate insulations. The remedial actions are also suggested in the study.
مجلة أكاديمية الجبل للعلوم الأساسية والتطبيقية
In this study, an energy and exergy analysis of the Derna steam power plant in Libya is presented. This study aims to identify the components with high energy and exergy losses which are leading to a decrease in the performance of the power plant. The largest place losses can be figured out hence to subsequently ensure where the greatest margin for improvement would be incurred. The influence of different parameters, such as temperatures and pressure values, on this analysis, is also conducted via the so-called Engineering Equation Solver software (EES). In terms of energy, the condenser is found to majorly have the highest energy losses of approximately 103MW which is received by the environment whilst the boiler losses are recorded to be about 24MW. As far as exergy is concerned, the boiler system is found to have the highest percentage ratio of exergy destruction to overall exergy destruction of 88 %, followed by the turbine of 8% and then the condenser of 3%. In addition, the th...
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.
. 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.
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%.
THERMOECONOMIC ANALYSIS OF ALKHOMS STEAM POWER PLANT AT DIFFERENT OPERATING LOADS
Journal of Engineering Research, 2021
Exergoeconomic (thermoeconomic) analysis is performed on Alkhoms steam power plant. The nominal power of the plant is 120 MW. The analysis is based on real-time data and performed for three different loads. The main factor of load variation is the variation of the steam mass flow rate. These loads are 120 MW (full load), 60 MW (part load), and 100 MW (real-time operation). It is worth to mention that high-pressure heaters are out of service these days. A systematic and general methodology for defining and calculating exergetic efficiencies, exergy destruction, and exergy related to costs in thermal systems is presented. The methodology is based on the Specific Exergy Costing (SPECO) method. Results of the exergy analysis showed the exergetic efficiency (effectiveness) increases from 34.74% at the real-time operation to 40.96% at full operating load, and hence the ratio of the total exergy destruction to fuel input exergy decreases from 64.46% at a real-time operation to 59.6 at part load up to 57.88% at full operating load. The exergoeconomic analysis results the average specific cost is 0.177 /kWhatreal−timeoperationand0.113/kWh at real-time operation and 0.113 /kWhatreal−timeoperationand0.113/kWh at part load, and 0.102 /kWhatfulloperatingloadtakingintoconsiderationtheescalationoffuelprice(levelizedfuelcost).Itisfoundthatthecostofexergydestructioninthesteamgeneratorpresentsthemaincontributiontothetotalcostofexergyloss;itsvaluevariesinthesteamgeneratorfrom8296/kWh at full operating load taking into consideration the escalation of fuel price (levelized fuel cost). It is found that the cost of exergy destruction in the steam generator presents the main contribution to the total cost of exergy loss; its value varies in the steam generator from 8296 /kWhatfulloperatingloadtakingintoconsiderationtheescalationoffuelprice(levelizedfuelcost).Itisfoundthatthecostofexergydestructioninthesteamgeneratorpresentsthemaincontributiontothetotalcostofexergyloss;itsvaluevariesinthesteamgeneratorfrom8296/h at the real-time operation to 6560 /hatfulloperatingload,whileexergydestructioncostatpartloadisatanotablevalueof3495/h at full operating load, while exergy destruction cost at part load is at a notable value of 3495 /hatfulloperatingload,whileexergydestructioncostatpartloadisatanotablevalueof3495/h due to low fuel consumption. The contributions and the variation of exergy destruction cost with load are lower for the other components.