Markku J. Lampinen
Aalto University, Department of Energy Technology, Applied Thermodynamics, Finland
Ralf Wiksten
Aalto University, Department of Energy Technology, Applied Thermodynamics, Finland
Arto Sarvi
Aalto University, Department of Energy Technology, Applied Thermodynamics, Finland
Kari Saari
Aalto University, Department of Energy Technology, Applied Thermodynamics, Finland
Marjut Penttinen
Aalto University, Department of Energy Technology, Applied Thermodynamics, Finland
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http://dx.doi.org/10.3384/ecp11057133Published in: World Renewable Energy Congress - Sweden; 8-13 May; 2011; Linköping; Sweden
Linköping Electronic Conference Proceedings 57:18, p. 133-139
Published: 2011-11-03
ISBN: 978-91-7393-070-3
ISSN: 1650-3686 (print), 1650-3740 (online)
The efficiency of internal combustion engines and gas turbine processes are free from Carnot limitations as they are not performing cycle processes – the initial state of the thermodynamic system is the fuel with air; whereas the final state is the flue gas; whose chemical composition is different than fuel and air. Therefore; as we show here; the theoretical thermodynamic efficiencies of ideal combustion engines and gas turbine processes can be very high; the same as it is for fuel cells. The entropy generation analysis; what we have done for the internal combustion engines and gas turbines; shows that they suffer for relatively low efficiencies because of the exergy losses in the combustion processes; i.e. for the reason that the combustion reaction takes place quite far from the equilibrium state. We have studied several different combustion processes in the Exergyproject of MIDE-program to find a method for decreasing the entropy generation in the combustion. If the entropy generation can be reduced; by any means; then as a “reward”; we get the outlet pressure of the flue gas higher than the inlet air pressure without using any compressor which in turn would then increase the efficiency essentially. We present here a theoretical description of a membrane combustion method which; with the aid of gasification; suits for bioenergy. Shortly; it can be described as a molecular scale oxygen gas compressor driven by the combustion reaction; where the affecting force is amplified by the electric field across the membrane.
Entropy; exergy; combustion; membrane; efficiency; combustion engine; gas turbine process
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