Thermodynamic Analysis of a Semi-Closed Oxy-fuel Combustion Combined Cycle

Abstract

Semi-closed oxy-fuel combustion combined cycle (SCOC-CC) is a strong concept of carbon capture and storage (CCS) in gas-fired power plants. This technology is similar to a conventional combined cycle, however oxygen instead of air is used in fuel combustion. In the oxy-fuel combined cycle, the gas turbine flue gases consist mainly of CO2 and H2O. One of the problems to implement this technology is the necessity of an air separation unit (ASU) to separate the oxygen from the air, which increases the energy consumption of the power plant. Thus, a comparative thermodynamic analysis was performed between a conventional combined cycle (base case) and an oxy-fuel combined cycle. The objective is to identify each technology's pros and cons, the influence of oxygen purity in the oxy-fuel combine cycle, and the main irreversibilities of each case. The SCOC-CC optimal operating point (maximum energy efficiency) was found utilizing particle swarm optimization (PSO), which lead to the optimal ASU oxygen purity of 95.99%. It was noticed that the oxy-fuel combined cycle first law efficiency is 6.9% lower than the base case, and the second law efficiency is 6.5% lower. Despite the efficiency loss the SCOC-CC is more environmentally friendly than the conventional combined cycle since it can theoretically capture all CO2 produced in the combustion chamber.

Keywords

• Oxy-fuel
• SCOC-CC
• Thermodynamic analysis
• CSS
• PSO

References

1. The United States Environmental Protection Agency (EPA), Overview of Greenhouse gases [Online]. Available: https://www.epa.gov/ghgemissions/overview-greenhouse-gases (accessed May 15, 2021).
2. L. Zheng, Oxy-fuel combustion for power generation and carbon dioxide (CO2) capture. Elsevier, 2011.
3. B. Metz et al., Carbon dioxide and storage: special report of the intergovernmental panel on climate change. Cambridge University Press, 2005.
4. M. Wilkinson et al., “Oxyfuel conversion of heater and boilers for CO2 capture” in 2nd Annual Conference on Carbon Sequestration, Virginia (USA), 2003.
5. National Energy Technology Laboratory, Commercial technologies for oxygen production. Available: https://www.netl.doe.gov/research/Coal/energy-systems/gasification/gasifipedia/commercial-oxygen (accessed May 15, 2021).
6. M. Maroto-Valer, Developments and innovation in carbon dioxide (CO2) capture and storage technology: carbon dioxide (CO2) capture, transport and industrial applications. Elsevier, 2010.
7. S. G. Sundkvist et al., “Concept for a combustion system in oxyfuel gas turbine combined cycles,” Journal of engineering for gas turbines and power, v. 136,n.10, 2014.
8. J. Szargut, D. R. Morris, F.R Steward, Exergy analysis of thermal, chemical, and metallurgical processes. New York: Hemisphere, 1988.

9. Y. Hu, H. Li, J. Yan, “Integration of evaporative gas turbine with oxy-fuel combustion for carbon dioxide capture,” International Journal of Green Energy, 7(6), 615-631, 2010.
10. A. Ebrahimi et al., "Energetic, exergetic and economic assessment of oxygen production from two columns cryogenic air separation unit." Energy 90, 1298-1316, 2015.
11. H. M. Kvamsdal, K. Jordal, O. Bolland. "A quantitative comparison of gas turbine cycles with CO2 capture." Energy 32.1, 10-24, 2007.
12. A. M. Y, Razak. Industrial gas turbines: performance and operability. Elsevier, 2007.
13. A. L. Sheldrake, Handbook of electrical engineering for practitioners in the oil, gas and petrochemical industry, John Wiley & Sons Ltd, Southern Gate, Chichester, 2003.
14. O. Bolland, Thermal Power Generation, Department of Energy and Process Engineering - NTNU, 2010.
15. R. Kehlhofer et al., Combined-cycle gas & steam turbine power plants. PennWell Books, LLC, 2009.
16. A. N. Dahlqvist (2016). Conceptual Thermodynamic Cycle and Aerodynamic Gas Turbine Design-on an Oxy-fuel Combined Cycle (Doctoral dissertation), Lund University, Sweden.
17. S. S. Maher, H.A Abid-Al-Rahman, Design of Dual Pressure Heat Recovery Steam Generator for Combined Power Plants [Online]. Available: http://conf-scoop.org/IEPEM-2013/11_Maher_IEPEM.pdf (accessed April 15, 2021).
18. L. Bojici, C. Neaga. "Technical optimization of a two-pressure level heat recovery steam generator." UPB Sci. Bull. Series D 74.2, 209-216, 2012.
19. S. C. Gülen, Gas turbines for electric power generation, Cambridge University Press, 2019.
20. GTW, Gas Turbine World: 2018 GTW Handbook (Vol. 33), Pequot Publishing.
21. R. C. Eberhart, J. Kennedy, "Particle swarm optimization.", Proceedings of the IEEE international conference on neural networks, Vol. 4, Citeseer, 1995.
22. A. F. Silva, A. C. Lemonge, Beatriz S. Lima. "Algoritmo de Otimização com Enxame de Partículas auxiliado por Metamodelos.", XI Simpósio de Mecânica Computacional, II Encontro Mineiro de Modelagem Computacional, SIMMEC/EMMCOMP, 2014.
23. Y. Shi, R. C. Eberhart, "Empirical study of particle swarm optimization.", Proceedings of the 1999 congress on evolutionary computation-CEC99 (Cat. No. 99TH8406). Vol. 3. IEEE, 1999.
24. I. C. Trelea, "The particle swarm optimization algorithm: convergence analysis and parameter selection.", Information processing letters 85.6 (2003): 317-325.
25. M. Juneja, S. K. Nagar. "Particle swarm optimization algorithm and its parameters: A review.", 2016 International Conference on Control, Computing, Communication and Materials (ICCCCM). IEEE, 2016.
26. N. Ferrari et al., “IEA GHG R&D programme report: Oxy-turbine power plants”, 2015.