Relevance Of Exergy Analysis In The Assessment Of Thermal Power Plant Performance

Authors

  • A. N. Anozie Applied Thermodynamics and Process Design Research Laboratory Department of Chemical Engineering Obafemi Awolowo University, Ile-Ife, Nigeria
  • O. J. Odejobi Applied Thermodynamics and Process Design Research Laboratory Department of Chemical Engineering Obafemi Awolowo University, Ile-Ife, Nigeria
  • O. P. Ayoola Applied Thermodynamics and Process Design Research Laboratory Department of Chemical Engineering Obafemi Awolowo University, Ile-Ife, Nigeria

Keywords:

Exergy, energy, thermal power plant, efficiency, irreversibility, units and subsystems

Abstract

 Exergy analysis of a natural gas based thermal power plant at Egbin, Ikorodu, Lagos State, was done to: evaluate the exergy and energy efficiencies and irreversibilities of units, subsystems and overall system; identify the units with large thermodynamic irreversibilities and investigate the causes of irreversibilities in the units and how they can be minimized; study the effect of interaction of units on the performance of subsystems and overall system. Process simulation was done using HYSYS, commercial process simulator software, and exergy analysis was done using Microsoft Excel Spreadsheet. It was found that the condenser unit has the lowest exergetic efficiency and the highest energetic efficiency of 22.6% and 99.9%, respectively. The furnace/boiler unit was found to have the highest irreversibility of 1484.3 MW and the regenerative unit has the lowest irreversibility of 9.7 MW. The study of the units interaction revealed that the furnace/boiler unit made the highest contribution of about 67% to the overall process irreversibility while the least contribution of 9.7% came from the turbines/generator unit. It was found that the optimum natural gas mass flow rate which optimized the flue gas temperature and CO2 emission was 40,000 kg/h rather than the operating rate of 45,570 kg/h.

Author Biographies

A. N. Anozie, Applied Thermodynamics and Process Design Research Laboratory Department of Chemical Engineering Obafemi Awolowo University, Ile-Ife, Nigeria

Applied Thermodynamics and Process Design Research Laboratory

Department of Chemical Engineering

 Obafemi Awolowo University, Ile-Ife, Nigeria

O. J. Odejobi, Applied Thermodynamics and Process Design Research Laboratory Department of Chemical Engineering Obafemi Awolowo University, Ile-Ife, Nigeria

Applied Thermodynamics and Process Design Research Laboratory

Department of Chemical Engineering

 Obafemi Awolowo University, Ile-Ife, Nigeria

O. P. Ayoola, Applied Thermodynamics and Process Design Research Laboratory Department of Chemical Engineering Obafemi Awolowo University, Ile-Ife, Nigeria

Applied Thermodynamics and Process Design Research Laboratory

Department of Chemical Engineering

 Obafemi Awolowo University, Ile-Ife, Nigeria

References

Alasfour, F.N. and Alajmi, H.F. Exergetic destructions in steam generation system: Azzour plant ”Int. Jour of Exergy, 4 (3): 271-285, 2000.
Bejan, A. Advanced Engineering Thermodynamics, Wiley, New York, 1988.
Caton, J.A. On the destruction of availability (exergy) due to combustion processes - with specific application to internal-combustion engines” Energy, 25(11): 1097-1117, 2000.
Cengel, Y.A. and Boles, M.A. Thermodynamics, McGraw-Hill, 2004.
Cornelissen, R.L. Thermodynamics and Sustainable Development: The Use of Exergy Analysis and the Reduction of Irreversibility, PhD Thesis, University of Twente, Netherlands, 1997.
Datta, A. Entropy Generation in a Confined Laminar Diffusion Flame, Comb. Sci. Tech., 159, 39- 56, 2000.
Debbigh, K.G. The Second Law Efficiency of Chemical Processes, Chem. Eng. Sc., 16(1), 1956
Dincer, I. and Al-Muslim, H. Thermodynamics analysis of reheat cycle steam power plants, Int. J. Energy Res. 25, 727-739, 2001.
HYSYS, Version 3.2 (Build 5029), Aspen Technology Inc., Licensed to TEAM LND, Calgary, Alberta, Canada, 2003.
Kwon, Y. Kwak, H. and S. Oh, S. Exergoeconomic analysis of gas turbine cogeneration system, Exergy an Int. Journal, 1, 31-40, 2001.
Linhoff, B. Thermodynamics Analysis in the Design of Process Networks, Ph.D. Thesis, University of Leeds, UK, 1979.
Mohamad, J.E. and Bandpy, M.G.Exergetic analysis of gas turbine plants. Int. J. Exergy, 2(1): 263- 279, 2005.
Moran, J. Availability analysis: A Guide to Efficient Energy Use. Englewood Cliffs, NJ: prentice–hall, 1982.
Moran, M.J. Engineering Thermodynamics, Mechanical Engineering Handbook, Boca Raton CRC Press LLC, 1999.
Nag, P.K. and De, S. Design and operation of a heat recovery steam generator with minimum irreversibility, Applied Thermal Engineering, 17 (4): 385-391, 1997.
Perry, R.H. and Green, D.W. Perry’s Chemical Engineer’s Handbook, 7th Ed. McGraw-Hill, 1997.
Rosen, M.A. Energy and exergy based comparison of coal fired and nuclear steam power plants, Exergy an Int. Journal, 1 (3): 125-127, 2001.
Rosen, M.A. and Dincer, I. Exergy-cost-energy-mass analysis of thermal systems and processes, Energy Convers. Management,44(10): 1633–1651, 2003.
Sciubba, E. and Su, T.M. Second law analysis of the steam turbine power cycle: a parameter study In: Gaggioli, R. A., ed., Computer-Aided Engineering of Energy Systems”, Proc. ASME Winter Annual Meeting, Anaheim, Cal., Exergy, Power engineering, Dec. 7-12, Second law analysis and modeling, 151-165, 1986.
Sengupta, S. Datta, A. and Duttagupta, S. Exergy analysis of a coal-based 210MW thermal power plant, Int. J. Energy Res., 31(1), 14-28, 2007.
Smith, J.M. Van Ness, H.C. Introduction to Chemical Engineering Thermodynamics, McGraw-Hill, 2004.
Som, S.K. Mondal, S.S. Dash, S.K. Energy and exergy balance in the process of pulverized coal combustion in a tubular Combustor. Journal of Heat Transfer, Transactions of the ASME 127, 1322-1333, 2005.

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Published

2009-11-01

How to Cite

Anozie, A. N., Odejobi, O. J., & Ayoola, O. P. (2009). Relevance Of Exergy Analysis In The Assessment Of Thermal Power Plant Performance. Ife Journal of Technology, 18(2), 42–50. Retrieved from https://ijt.ng/index.php/ijt/article/view/36