THERMAL SCIENCE

International Scientific Journal

EXERGY EFFICIENCY ANALYSIS OF LIGNITE-FIRED STEAM GENERATOR

ABSTRACT
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.
KEYWORDS
PAPER SUBMITTED: 2018-01-31
PAPER REVISED: 2018-06-18
PAPER ACCEPTED: 2018-06-18
PUBLISHED ONLINE: 2018-09-29
DOI REFERENCE: https://doi.org/10.2298/TSCI180131265K
CITATION EXPORT: view in browser or download as text file
THERMAL SCIENCE YEAR 2018, VOLUME 22, ISSUE 5, PAGES [2087 - 2101]
REFERENCES
  1. Rant, Z., Exergy, a New Word for Technical Work Ability (in German), Forschung auf dem Gebiete des Ingenieurwesens, 22 (1956), 1, pp. 36-37
  2. Rant, Z., Termodinamika, Knjiga za Uk in Prakso, University of Ljubljana, Ljubljana, Slovenia, 1963
  3. Perrot, P., A to Z of Thermodynamics, Oxford University Press, Oxford, UK, 1998
  4. Wall, G., Exergy Tools, Proceedings of the Institution of Mechanical Engineers Part A: Journal of Power and Energy, 217 (2003), 2, pp. 125-136
  5. Kaushik, S. C., et al., Energy and Exergy Analyses of Thermal Power Plants: A Review, Renewable and Sustainable Energy Reviews, 15 (2011), 4, pp. 1857-1872
  6. Koroneos, C. J., et al., Exergy Analysis of a 300 MW Lignite Thermoelectric Power Plant, Energy, 75 (2014), Oct., pp. 304-311
  7. Regulagadda, P., et al., Exergy Analysis of a Thermal Power Plant with Measured Boiler and Turbine Losses, Applied Thermal Engineering, 30 (2010), 8-9, pp. 970-976
  8. Han, X., et al., Exergy Analysis of the Flue Gas Pre-dried Lignite-fired Power System Based on the Boiler with Open Pulverizing System, Energy, 106 (2016), July, pp. 285-300
  9. Habib, M. A., Zubair, S. M., 2nd - Law-based Thermodynamic Analysis of Regenerative-reheat Rankine- cycle Power Plant, Energy, 17 (1992), 3, pp. 295-301
  10. Dincer, H. A., Thermodynamic Analysis of Reheat Cycle Steam Power Plants, International Journal of Energy Research, 25 (2001), 8, pp. 727-739
  11. Sengupta, S., et al., Exergy Analysis of a Coal-based 210 MW Thermal Power Plant, International Journal of Energy Research, 31 (2007), 1, pp. 14-28
  12. Xiong, J., et al., Thermoeconomic Operation Optimization of a Coal-fired Power Plant, Energy, 42 (2012), 1, pp. 486-496
  13. Rosen, M. A., Dincer, I., Exergoeconomic Analysis of Power Plants Operating on Various Fuels, Applied Thermal Engineering, 23 (2003), 6, pp. 643-658
  14. Kwak, H. Y., et al., Exergo-economic and Thermodynamic Analysis of Power Plants, Energy, 28 (2003), 4, pp. 343-360
  15. Unal, F., Ozkan, D. B., Application of Exergoeconomic Analysis for Power Plants, Thermal Science, (2017), in press
  16. Groniewsky, A., Exergoeconomic Optimization of a Thermal Power Plant Using Particle Swarm Optimization, Thermal Science, 17 (2013), 2, pp. 509-524
  17. Mitrovic, D. M., et al., Comparative Exergetic Performance Analysis for Certain Thermal Power Plants in Serbia, Thermal Science, 20 (2016), Suppl. 5, pp. S1259-S1269
  18. Erdem, H. H., et al., Comparative Energetic and Exergetic Performance Analysis for Coal-fired Thermal Power Plants in Turkey, International Journal of Thermal Sciences, 48 (2009), 11, pp. 2179-2186
  19. Aljundi, I. H., Energy and Exergy Analysis of a Steam Power Plant in Jordan, Applied Thermal Engineering, 29 (2009), 2-3, pp. 324-328
  20. Datta, A., et al., Exergy Analysis of a Coal-based 210 MW Thermal Power Plant, International Journal of Energy Research, 31 (2007), 1, pp. 14-28
  21. Reddy, B. V., Butcher, C. J., Second Law Analysis of a Waste Heat Recovery Based Power Generation System, International Journal of Heat and Mass Transfer, 50 (2007), 11-12, pp. 2355-2363
  22. Suresh, M. V. J. J., et al., Energy and Exergy Analysis of Thermal Power Plants Based on Advanced Steam Parameters, Proceedings, National Conference on Advances in Energy Research, Mumbai, India, 2006
  23. Murugan, R. S., Subbarao, P. M. V., Efficiency Enhancement in a Rankine Cycle Power Plant: Combined Cycle Approach, Proceedings of the Institution of Mechanical Engineers Part A: Journal of Power and Energy, 222 (2008), 8, pp. 753-760
  24. Ferdelji, N., et al., Exergy Analysis of a Co-generation Plant, Thermal Science, 12 (2008), 4, pp. 75-88
  25. Mahamud, R., et al., Exergy Analysis and Efficiency Improvement of a Coal Fired Thermal Power Plant in Queensland, in: Thermal Power Plants ‒ Advanced Applications (Ed. Mohammad Rasul), IntechOpen, London, UK, 2013
  26. Rosen, M. A., Can Exergy Help us Understand and Address Environmental Concerns?, Exergy, An International Journal, 2 (2002), 4, pp. 214-217
  27. ***, Working Instructions for Boiler and Turbine in TPP Kosovo B, Stein Industrie, 1996
  28. Kotas, T. J., The Exergy Method of Thermal Plant Analysis, Exergon Publishing Company UK Ltd., London, UK, 2012
  29. Kuznetsov, N. V., et al., Thermal Calculation of Boiler Units, The Normative Method (in Russian), Energiya Press, Moscow, Russia, 1973
  30. Krasniqi Alidema, D., et al., Performance Analysis of Coal-fired Power Plant Based on the Exergy Method, Proceedings, 12th SDEWES Conference, Dubrovnik, Croatia, 2017
  31. Blokh, A. G., Heat Transfer in Steam Boiler Furnaces, Energoatomizdat, Leningrad, Russia, 1984
  32. Filkoski, R. V., et al., Optimisation of Pulverised Coal Combustion by Means of CFD/CTA Modelling, Thermal Science, 10 (2006), 3, pp. 161-179
  33. Filkoski, R. V., et al., Assessment of the Impact of Under-Fire Air Introduction on the Pulverised Coal Combustion Efficiency, Chemical Engineering Transactions, 34 (2013), Oct., pp. 25-30
  34. Zaleta-Aguilar, A., et al., Concept on Thermo-economic Evaluation of Steam Turbines, Applied Thermal Engineering, 27 (2007), 2-3, pp. 457-466
  35. Krasniqi Alidema, D., Energy and Exergy Analysis of Working Cycles of Coal-fired Thermal Power Plant at Different Operating Conditions, Ph. D. thesis, Ss Cyril and Methodius University, Skopje, Macedonia, 2018

© 2018 Society of Thermal Engineers of Serbia. Published by the Vinča Institute of Nuclear Sciences, Belgrade, Serbia. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International licence