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Thermodynamic cycle analysis and optimization to improve efficiency in a 700 °C ultra-supercritical double reheat system

  • Mei YangEmail author
  • Yun-long Zhou
  • Di Wang
  • Jiayu Han
  • Yujia Yan
Article
  • 22 Downloads

Abstract

When increasing steam parameters, the incomplete thermodynamic cycle and large irreversible system losses are bottlenecks in improving thermal efficiency in ultra-supercritical power plants. In this study, a comprehensive analysis of both parameter optimization and system cycle analysis is carried out for a 1000-MW double reheat ultra-supercritical thermal power plant. First, the genetic algorithm is used to optimize the primary and double thermal pressure, as well as the steam extraction parameters of the steam turbine. Then, a thermodynamic optimization model is proposed to analyze performance. Moreover, the exergy analysis method is applied to reveal the irreversibility mechanism in the thermodynamic cycle. In order to further solve the energy-grade mismatch problem, the performance of a regenerative steam turbine thermal system is improved based on the optimized system. The results indicate that the power generation efficiency of the optimized system is 0.31% higher than that of the prototype system, and the heat consumption rate is decreased by 43.67 kJ (kW h)−1. The power generation efficiency in the regenerative steam turbine system is up to 52.42%, which is 1.44% higher than that of the optimized system. Therefore, an effective method to improve the thermal efficiency is obtained through the thermodynamic cycle analysis and optimization for 700 °C ultra-supercritical double reheats systems.

Keywords

700 °C ultra-supercritical power plant Thermodynamic cycle optimization Exergy analysis The power generation efficiency Thermodynamic performance 

List of symbols

W

The amount of the work by a steam turbine, kJ kg−1

\(\eta_{\text{T}}\)

The efficiency of the steam turbine system

e0

The specific exergy of the supply system, kJ kg−1

ew1

The exergy of feed water, kJ kg−1

D0

The mass flow rate of main-steam, kg s−1

Drh1

The mass flow rate of steam single reheat steam, kg s−1

Drh2

The mass flow rate of double reheat steam, kg s−1

p0

The main-steam pressure

p1

The first reheat pressure

p2

The second reheat pressure

p0i

No. i the extraction pressure

erh1

The exergy of intermedium-pressure turbines inlet steam, kJ kg−1

erh2

The exergy of low-pressure turbines inlet steam, kJ kg−1

e2

The exergy of intermedium-pressure turbines exhaust steam, kJ kg−1

e3

The exergy of low-pressure turbines exhaust steam, kJ kg−1

qcp

The heat consumption rate

\(\eta^{\text{e}}\)

The exergy efficiency

e

The exergy losses, kJ kg−1

em,in

The specific exergy of inlet, kJ kg−1

em,out

The specific exergy of outlet, kJ kg−1

eq

The specific exergy of heat flux, kJ kg−1

h1

The specific enthalpy of the working medium at the given state, kJ kg−1

hamb

The specific enthalpy of the working medium at the environmental state, kJ kg−1

T

The average temperature of heat absorption process of working medium, K

Tamb

The environment temperature, K

S1

The specific enthalpy of the working medium at the given state, kJ (kg K)−1

Samb

The specific entropy of the working medium at the environmental state, kJ (kg K)−1

sg

The entropy production of irreversible processes, kJ (kg K)−1

Qcp

Heat consumption of power plants, kJ h−1

Pe

The output power of generator, kW

B

The fuel consumption per unit time of boiler, kg h−1

Qnet,p

The low heat value (LHV) of coal, kJ kg−1

qcp

The unit of heat consumption rate, kJ (kW h)−1

w

The specific work of the power equipment, kJ kg−1

q

Heat absorbed by the working medium kJ kg−1

B

Boiler

HP

High-pressure cylinder

IP

Intermediate-pressure cylinder

LP

Low-pressure cylinder

G

Generator

C

Condenser

CP

Condensate pump

Hi

No. i regenerative heater

Notes

Acknowledgements

This work has been supported by the National key research and development program (Project No. 2018YFB0604404), and Science and Technology Development Project of Jilin Province of China (Project No. 20190103008JH).

References

  1. 1.
  2. 2.
    BP Energy Outlook 2018 Edition. BP. https://www.bp.com/en/global/corporate/energy-economics/energy-outlook.html. Accessed 20 Feb 2018.
  3. 3.
    Kumar R, Jilte R, Ahmadi MH, et al. A simulation model for thermal performance prediction of a coal-fired power plant. Int J Low Carbon Technol. 2019;14:122–34.CrossRefGoogle Scholar
  4. 4.
    Kumar R, Jilte R, Nikam KC, et al. Status of carbon capture and storage in India’s coal fired power plants: a critical review. Environ Technol Innov. 2018;13:94–103.CrossRefGoogle Scholar
  5. 5.
    Li H, Ma L. Analysis on recent development of energy investment in China. Sino Global Energy. 2018;23:3–13.Google Scholar
  6. 6.
    Li Q, Wang C. Analysis on new energy development based on the 13th five-year electric power planning. Electric Power. 2017;50:30–6.Google Scholar
  7. 7.
    Cao Y, Hu B, Liang L, et al. Optimization of a combined reheating/regenerative/internal regenerative organic Rankine cycle based on exergy analysis. Renew Energy Resour. 2015;33:741–6.Google Scholar
  8. 8.
    Nouri M, Namar MM, Jahanian O. Analysis of a developed Brayton cycled CHP system using ORC and CAES based on first and second law of thermodynamics. J Therm Anal Calorim. 2019;135:1743–52.CrossRefGoogle Scholar
  9. 9.
    Acar MS, Arslan O. Energy and exergy analysis of sola energy-integrated, geothermal energy-powered Orgranic Rankine Cycle. J Therm Anal Calorim. 2019;137:659–66.CrossRefGoogle Scholar
  10. 10.
    Sadeghi S, Maghsoudi P, Shabani B, et al. Performance analysis and multi-objective optimization of an organic Rankine cycle with binary zeotropic working fluid employing modified artificial bee colony algorithm. J Therm Anal Calorim. 2019;136:1645–65.CrossRefGoogle Scholar
  11. 11.
    Ziebik A, Gladysz P. Analysis of the cumulative exergy consumption of an integrated oxy-fuel combustion power plant integrated with a CO2 processing unit. Arch Thermodyn. 2013;34:105–22.CrossRefGoogle Scholar
  12. 12.
    Crespi F, Gavagnin G, Sanchez D, et al. Supercritical carbon dioxide cycles for power generation, a review. Appl Energy. 2017;195:152–83.CrossRefGoogle Scholar
  13. 13.
    Uysal C, Kurt H, Kwak HY. Exergetic and thermo economic analyses of a coal-fired power plant. Int J Therm Sci. 2017;117:106–20.CrossRefGoogle Scholar
  14. 14.
    Fan C, Pei D, Wei H. A novel cascade energy utilization to improve efficiency of double reheat cycle. Energy Convers Manag. 2018;171:1388–96.CrossRefGoogle Scholar
  15. 15.
    Łukowicz H, Dykas S, Rulik S, et al. Thermodynamic and economic analysis of a 900 MW ultra-supercritical power unit. Arch Thermodyn. 2011;32:231–44.CrossRefGoogle Scholar
  16. 16.
    Liu Y, Sui J, Liu H. Research on heating system of serial-parallel coupling absorption heat pump for coal fired power plants. Proc CSEE. 2016;36:6148–55.Google Scholar
  17. 17.
    Zhang X, Chen H. Thermodynamic analysis of heat pump heating supply systems with circulating water heat recovery. Proc CSEE. 2013;33:2–8.Google Scholar
  18. 18.
    Demir H, Mobedi M, Ulku S. A review on adsorption heat pump: problems and solutions. Renew Sustain Energy Rev. 2008;12:2381–403.CrossRefGoogle Scholar
  19. 19.
    Feng W. Developing green, highly efficient coal-fired power technologies. New York: Amer Soc Mechanical Engineers; 2015.Google Scholar
  20. 20.
    Feng W. Development of China’s supercritical coal fired power generation unit. J Shanghai Univ Electric Power. 2011;27:417–22.Google Scholar
  21. 21.
    Zhou L, Hua M, Wang W, et al. A variable condition calculation method for main steam parameters and the heat rate correction curves. J Chin Soc Power Eng. 2011;31:387–90.Google Scholar
  22. 22.
    Srinivas T, Gupta A, Reddy BV. Sensitivity analysis of STIG based combined cycle with dual pressure HRSG. Int J Therm Sci. 2008;47:1226–34.CrossRefGoogle Scholar
  23. 23.
    Espatolero S, Romeo LM, Cortés C. Efficiency improvement strategies for the feedwater heaters network designing in supercritical coal-fired power plants. Appl Therm Eng. 2014;73:449–60.CrossRefGoogle Scholar
  24. 24.
    Cai X, Zhang Y, Li Y, et al. Design and exergy analysis on thermodynamic system of a 700°C ultra supercritical coal-fired power generating set. J Chin Soc Power Eng. 2012;32:971–8.Google Scholar
  25. 25.
    Xu C, Xu G, Zhu M, et al. Thermodynamic analysis and economic evaluation of a 1000 MW bituminous coal fired power plant incorporating low-temperature pre-drying (LTPD). Appl Therm Eng. 2016;96:613–22.CrossRefGoogle Scholar
  26. 26.
    Bugge J, Kjaer S, Blum R. High-efficiency coal-fired power plants development and perspectives. Energy. 2016;31:1437–45.CrossRefGoogle Scholar
  27. 27.
    European AD700 project. https://projectweb.elsam-eng.com/AD700/default.aspx. Accessed 27 Oct 2005.
  28. 28.
    Beer JM. High efficiency electric power generation: the environmental role. Prog Energy Combust Sci. 2007;33:107–34.CrossRefGoogle Scholar
  29. 29.
    Weitzel P. Steam generator for advanced ultra-supercritical power plants 700 to 760 °C. In: ASME 2011 power conference. 2011.Google Scholar
  30. 30.
    Yilmaz F. Energy, exergy and economic analyses of a novel hybrid ocean thermal energy conversion system for clean power production. Energy Convers Manag. 2019;196:557–66.CrossRefGoogle Scholar
  31. 31.
    Ahmadi MH, Nazari MA, Sadeghzadeh M, et al. Thermodynamic and economic analysis of performance evaluation of all the thermal power plants: a review. Energy Sci Eng. 2019;7:30–65.CrossRefGoogle Scholar
  32. 32.
    Ahmadi MH, Sadaghiani MS, Pourfayaz F, et al. Energy and exergy analyses of a solid oxide fuel cell-gas turbine-organic rankine cycle power plant with liquefied natural gas as heat sink. Entropy. 2018;20:1–22.Google Scholar
  33. 33.
    Vakilabadi MA, Bidi M, et al. Exergy analysis of a hybrid solar-fossil fuel power plant. Energy Sci Eng. 2019;7(1):146–61.CrossRefGoogle Scholar
  34. 34.
    Naeimi A, Bidi M, Ahmadi MH, et al. Design and exergy analysis of waste heat recovery system and gas engine for power generation in Tehran cement factory. Therm Sci Eng Prog. 2019;9:299–307.CrossRefGoogle Scholar
  35. 35.
    Gargari SG, Rahimi M, Ghaebi H. Energy, exergy, economic and environmental analysis and optimization of a novel biogas-based multigeneration system based on gas turbine-modular helium reactor cycle. Energy Convers Manag. 2019;185:816–35.CrossRefGoogle Scholar
  36. 36.
    Wang LG, Yang YP, Dong CQ, et al. Parametric optimization of supercritical coal-fired power plants by MINLP and differential evolution. Energy Convers Manag. 2014;85:828–38.CrossRefGoogle Scholar
  37. 37.
    Srinivas T, Gupta AVSSKS, Reddy BV. Sensitivity analysis of STIG based combined cycle with dual pressure HRSG. Int J Therm Sci. 2008;47:1226–34.CrossRefGoogle Scholar
  38. 38.
    Espatolero S, Romeo LM, Cortés C. Efficiency improvement strategies for the feedwater heaters network designing in supercritical coal-fired power plants. Appl Therm Eng. 2014;73:449–60.CrossRefGoogle Scholar
  39. 39.
    Gu Y, Wang S. Thermal economic analysis of a double reheat ultra supercritical pressure unit. J Xi’an Univ Technol. 2013;29:357–61.Google Scholar
  40. 40.
    STEAG Energy Services GmbH, EBSILON Professional 2010.Google Scholar
  41. 41.
    Cifre PG, Brechtel K, Hoch S, et al. Integration of a chemical process model in a power plant modeling tool for the simulation of an amine based CO2 scrubber. Fuel. 2009;88:2481–8.CrossRefGoogle Scholar
  42. 42.
    Bruhn M. Hybrid geothermal-fossil electricity generation from low enthalpy geothermal resources: geothermal feed-water preheating in conventional power plants. Energy. 2002;27:329–46.CrossRefGoogle Scholar
  43. 43.
    Xu G, Zhou L, Zhao S, et al. Optimum superheat utilization of extraction steam in double reheat ultra-supercritical power plants. Appl Energy. 2015;160:863–72.CrossRefGoogle Scholar
  44. 44.
    Wang L, Yang Y, Dong C, et al. Multi-objective optimization of coal-fired power plants using differential evolution. Appl Energy. 2014;115:254–64.CrossRefGoogle Scholar
  45. 45.
    Yan M, Zhang L, Shi Y, et al. A novel boiler cold-end optimization system based on bypass flue in coal-fired power plants: heat recovery from wet flue gas. Energy. 2018;152:84–94.CrossRefGoogle Scholar
  46. 46.
    Holland JH. Adaptation in nature and artificial systems: an introductory analysis with applications to biology, control and artificial intelligence. Cambridge: MIT Press; 1992.CrossRefGoogle Scholar
  47. 47.
    Wang J, Dai Y, Gao L. Exergy analysis and parametric optimizations for different cogeneration power plants in cement industry. Appl Energy. 2009;86:941–8.CrossRefGoogle Scholar
  48. 48.
    Suresh MVJJ, Reddy KS. Thermodynamic optimization of advanced steam power plants retrofitted for oxy-coal combustion. J Eng Gas Turb Power. 2011;133:1–12.CrossRefGoogle Scholar
  49. 49.
    Zhou L, Xu G, Zhao S, et al. Parametric analysis and process optimization of steam cycle in double reheat ultra-supercritical power plants. Appl Therm Eng. 2016;99:652–60.CrossRefGoogle Scholar

Copyright information

© Akadémiai Kiadó, Budapest, Hungary 2019

Authors and Affiliations

  1. 1.School of Energy and Power EngineeringNortheast Electric Power UniversityJilinChina

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