Energy and Exergy Analysis for Three Type 500MW Steam Power Plants

2011 ◽  
Vol 148-149 ◽  
pp. 1131-1136
Author(s):  
Zhi Li ◽  
Zhong Min Li ◽  
Zhan Liang Yan

The paper shows the comparison of energy and exergy analysis of thermal power plants based on advanced steam parameters in China climatic conditions. The research contains coal-based thermal power plants using sub-critical, super-critical, and ultra-supercritical steam conditions. The design configurations of 500 MW unit size were considered. The research contains the effect of condenser pressure on plant and exergy efficiency. The effect of high grade coal on performance parameters as compared to typical China low grade coal was also studied. The major exergy loss took place in coal combustion followed by the steam generator. Due to condenser pressure limitation, the maximum possible overall energy efficiency was found to be about 44.4% with the ultra-supercritical power plant. Installing coal-based thermal power plants based on advanced steam parameters in China will be a prospective option aiding energy self-sufficiency.

2010 ◽  
Vol 01 (03) ◽  
pp. 143-152 ◽  
Author(s):  
Vundela Siva Reddy ◽  
Subash Chndra Kaushik ◽  
Sudhir Kumar Tyagi ◽  
Narayanlal Panwar

2016 ◽  
Author(s):  
João Silva ◽  
Senhorinha F. Teixeira ◽  
Simone Preziati ◽  
José Carlos Teixeira

The fulfilment of energy targets regarding the use of renewable energy has been a strong incentive to the development of dedicated power plants using biomass. Because these facilities operate with low value residues, this orientation has also received a strong incentive by the quest to reduce the amount of fuel in the woods and lowering the risk of fire. This issue is a major problem in dry climates. Although the number of plants planned for Portugal was very large, the actual number of units in operation is small. The first plant to enter production in Portugal was the thermal power plant of Mortágua. In this paper the energy and exergy analysis in this plant is presented. The objective of this work is to develop an analysis for the energy conversion in the plant. This is based on parameters that were retrieved during its normal operation and include: biomass and air flow rate, temperature measurements of the flue gases throughout the facility including the economizer, the two superheaters and flue gas composition. The elemental analysis of the biomass resulting from a blend of various sources was measured in addition to its moisture (ranging between 20 and 45% depending on the sources). The analysis was carried out for a fuel batch with a moisture of 35%. The plant was operated at three loads (full load, 80% and 65% load) and from the energy/mass balances the overall efficiency was calculated to be approximately 26%. The data were also used to perform a second law analysis of the plant which enables the calculation of the exergy destruction in the various components of the facility, including the external irreversibility. It was observed that the combustion chamber is the prime contributor to the overall loss of efficiency. The exergy efficiency was found approximately 22%.


2019 ◽  
Vol 124 ◽  
pp. 01040 ◽  
Author(s):  
D. T. Nguen ◽  
D. N. Pham ◽  
G. R. Mingaleeva ◽  
O. V. Afanaseva ◽  
P. Zunino

The growing demand for energy and fossil fuels creates increased number of difficulties, while renewable energy sources are still rarely used worldwide, particularly in Vietnam. In this article hybrid thermal power plants based on gas turbine plants are discussed, the increased efficiency of which is achieved by air heating after the compressor in solar air heaters. The basic design equations and the results of evaluating the efficiency and fuel consumption are presented for two thermal power plants of 4.6 MW and 11.8 MW. The dependence of the results on the intensity of solar extraction for the climatic conditions of the Ninh Thuan province of the Republic of Vietnam is discussed.


2016 ◽  
Vol 130 ◽  
pp. 219-229 ◽  
Author(s):  
Peng Fu ◽  
Ningling Wang ◽  
Ligang Wang ◽  
Tatiana Morosuk ◽  
Yongping Yang ◽  
...  

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Hui Hong ◽  
Hongguang Jin ◽  
Jun Sui ◽  
Jun Ji

Solar thermochemical processes inherently included the conversion of solar thermal energy into chemical energy. In this paper, a new mechanism of upgrading the energy level of solar thermal energy at around 200°C was revealed based on the second law thermodynamics and was then experimentally proven. An expression was derived to describe the upgrading of the energy level from low-grade solar thermal energy to high-grade chemical energy. The resulting equation explicitly reveals the interrelations of energy levels between middle-temperature solar thermal energy and methanol fuel, and identifies the interactions of mean solar flux and the reactivity of methanol decomposition. The proposed mechanism was experimentally verified by using the fabricated 5kW prototype of the receiver∕reactor. The agreement between the theoretical and the experimental results proves the validity of the mechanism for upgrading the energy level of low-grade solar thermal energy by integrating clean synthetic fuel. Moreover, the application of this new middle-temperature solar∕methanol hybrid thermochemical process into a combined cycle is expected to have a net solar-to-electric efficiency of about 27.8%, which is competitive with other solar-hybrid thermal power plants using high-temperature solar thermal energy. The results obtained here indicate the possibility of utilizing solar thermal energy at around 200°C for electricity generation with high efficiency by upgrading the energy level of solar thermal energy, and provide an enhancement to solar thermal power plants with the development of this low-grade solar thermochemical technology in the near future.


2018 ◽  
Vol 22 (5) ◽  
pp. 2087-2101
Author(s):  
Drenusha Krasniqi-Alidema ◽  
Risto Filkoski ◽  
Marigona Krasniqi

The operation of steam generators and thermal power plants is commonly evaluated on a basis of energy analysis. However, the real useful energy loss cannot be completely justified only by the First law of thermodynamics, since it does not differentiate between the quality and amount of energy. The present work aims to give a contribution towards identification of the sources and magnitude of thermodynamic inefficiencies in utility steam generators. The work deals with a parallel analysis of the energy and exergy balances of a coal-fired steam generator that belongs to a 315 MWe power generation unit. The steam generator is de-signed for operation on low grade coal - lignite with net calorific value 6280 to 9211 kJ/kg, in a cycle at 545?C/177.4 bar, with feed water temperature 251?C, combustion air preheated to 272?C and outlet flue gas temperature 160?C. Since the largest exergy dissipation in the thermal power plant cycle occurs in the steam generator, energy, and exergy balances of the furnace and heat exchanging surfaces are established in order to identify the main sources of inefficiency. On a basis of the analysis, optimization of the combustion and heat transfer processes can be achieved through a set of measures, including retrofitting option of lignite pre-drying with flue gas and air preheating with dryer exhaust gases.


2020 ◽  
pp. 1-46
Author(s):  
Alain Christian Biboum ◽  
Ahmet Yilanci

Abstract In this study, it is aimed to conduct the thermodynamic and economic analysis of solar thermal power plants using parabolic trough collectors (PTC), linear Fresnel reflectors (LFR) and solar tower (ST) technologies for Cameroon. The analysis is performed for each power plant with the installed capacity of 5 MWe. Initial investment costs for the solar thermal power plants using PTC, LFR and ST technologies are estimated to be 33.49 Million USD, 18.77 Million USD and 36.31 Million USD while levelized costs of electricity (LCOE) are found to be varying from 145.6 USD/MWh to 186.8 USD/MWh, 112.2 USD/MWh to 154.2 USD/MWh and 179.2 USD/MWh to 220.4 USD/MWh, respectively. For the solar thermal power plants using PTC, LFR and ST technologies, payback periods are obtained to be 6.57 years, 6.84 years and 6.02 years, and also, internal rates on the return are calculated to be 21.03%, 20.42% and 22.47%, respectively. Overall energy and exergy efficiency values are found to be 13.39% and 14.37%; 11.90% and 13.74%; 12.13% and 13.64% for the solar thermal power plants using PTC, LFR and ST technologies, respectively. In conclusion, it is seen that LFR technology presents the best performance with the combination of thermodynamic and economic metrics for the deployment of solar thermal power plants in the countries in sub-Saharan Africa like Cameroon.


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