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Combustion irreversibilities: Numerical simulation and analysis


An exergy analysis was performed considering the combustion of methane and agro-industrial residues produced in Portugal (forest residues and vines pruning). Regarding that the irreversibilities of a thermodynamic process are path dependent, the combustion process was considering as resulting from different hypothetical paths each one characterized by four main sub-processes: reactant mixing, fuel oxidation, internal thermal energy exchange (heat transfer), and product mixing. The exergetic efficiency was computed using a zero dimensional model developed by using a Visual Basic home code. It was concluded that the exergy losses were mainly due to the internal thermal energy exchange sub-process. The exergy losses from this sub-process are higher when the reactants are preheated up to the ignition temperature without previous fuel oxidation. On the other hand, the global exergy destruction can be minored increasing the pressure, the reactants temperature and the oxygen content on the oxidant stream. This methodology allows the identification of the phenomena and processes that have larger exergy losses, the understanding of why these losses occur and how the exergy changes with the parameters associated to each system which is crucial to implement the syngas combustion from biomass products as a competitive technology.

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  1. Derived from the website of Energy Information Administration (EIA) at /, accessed at 30-12-2011

  2. S.K. Som, A. Datta, Thermodynamic irreversibilities and exergy balance in combustion processes, Prog Energ Combust 34 (2008) 351–376.

    Article  Google Scholar 

  3. M.A. Rosen, I. Dincer, Exergy as the confluence of energy, environment and sustainable development, Exergy Int J 1 (2001) 3–13.

    Article  Google Scholar 

  4. M.A. Rosen, Clarifying thermodynamic efficiencies and losses via exergy, Exergy Int J 2 (2002) 3–5.

    Article  Google Scholar 

  5. H. Taniguchi, K. Mouri, T. Nakahara, N. Arai, Exergy analysis on combustion and energy conversion processes, Energy, 30 (2005) 111–117.

    Article  Google Scholar 

  6. S. Song, S. Douvartzides, P. Tsiakaras, Exergy analysis of an ethanol fuelled proton exchange membrane (PEM) fuel cell system for automobile applications, J Power Sources 145 (2005) 502–514.

    Article  Google Scholar 

  7. E. Baniasadi, I. Dincer, Energy and exergy analyses of a combined ammonia-fed solid oxide fuel cell system for vehicular applications, Int J Hydrogen Energ 36 (2011) 1128–1136.

    Article  Google Scholar 

  8. A. Kazim, Exergy analysis of a PEM fuel cell at variable operating conditions, Energ Convers Manage 45 (2004) 1949–1961.

    Article  Google Scholar 

  9. H. Torío, A. Angelotti, D. Schmidt, Exergy analysis of renewable energy-based climatisation systems for buildings: A critical review, Energ Buildings, 41 (2009) 240–271.

    Article  Google Scholar 

  10. C. Yucer, A. Hepbasli, Thermodynamic analysis of a building using exergy analysis method, Energ Buildings 43 (2011) 536–542.

    Article  Google Scholar 

  11. H. Caliskan, A. Hepbasli, Energy and exergy analyses of ice rink buildings at varying reference temperatures, Energ Buildings 42 (2010) 1418–1425.

    Article  Google Scholar 

  12. N. Lior, Irreversibility in combustion, Invited Keynote Paper, ProcECOS, Istanbul, (2001) 39–48.

  13. N. Lior, S. Darkin, H.S. Al-Sharqawi, The exergy fields in transport processes: Their calculation and use, Energy 31 (2006) 553–578.

    Article  Google Scholar 

  14. A. Datta, S.K. Som, Energy and exergy balance in a gas turbine combustor, J Power Energy 213A (1999) 23–32.

    Article  Google Scholar 

  15. W. R. Dunbar, N. Lior, Understanding combustion irreversibilities, Second Law Analysis, Ind Environ Appl 25 (1991) 81–90.

    Google Scholar 

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Silva, V., Rouboa, A. Combustion irreversibilities: Numerical simulation and analysis. J. Therm. Sci. 21, 377–383 (2012).

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  • Exergy
  • Combustion paths
  • Combustion sub-processes
  • Exergetic efficiency
  • Visual Basic
  • Syngas