System Analysis on Supercritical CO2 Power Cycle with Circulating Fluidized Bed Oxy-Coal Combustion
- 14 Downloads
Supercritical carbon dioxide (S-CO2) Brayton power cycle is a competitive technology to achieve high efficiency in a variety of applications. However, in coal power applications, the CO2 generated from coal combustion still discharges into the atmosphere causing a series of environment problems. In this work, an 300 MWe S-CO2 power cycle with circulating fluidized bed (CFB) oxy-coal combustion was established including air separation unit (ASU), CFB boiler, recuperator system and carbon dioxide compression and purification unit (CPU). Based on the material and energy conservation, the cycle efficiency of S-CO2 (620°C, 25 MPa) Brayton power cycle with CFB oxy-coal combustion is evaluated compared to the oxy-coal combustion steam Rankine cycle and S-CO2 Brayton power cycle with the 31.65 kg/s coal supply. After that, the influence of several factors, e.g., exhaust flue gas temperature, split ratio in recuperator system and the oxygen supply on the cycle efficiency was investigated and analyzed. The results show that the net efficiency of S-CO2 power cycle with CFB oxy-coal combustion (32.67%) is much higher than the steam Rankine cycle utilizing CFB with 17.5 Mpa, 540°C steam (27.3%), and 25 Mpa, 620°C steam (30.15%) under the same exhaust flue gas temperature. In addition, lower exhaust flue gas temperature and higher split ratio are preferred to achieve higher cycle efficiency. Lower oxygen supply can reduce the energy consumption of ASU and CPU, further increasing the system net efficiency. However, the energy losses of ASU and CPU are still very large in oxy-coal combustion and need to be improved in further work.
KeywordsS-CO2 oxy-coal combustion CO2 capture CFB boiler process simulation
Unable to display preview. Download preview PDF.
This work was supported by the National key research and development program of China (project number: 2017YFB0601802), the project of the National Natural Science Foundation of China (project number: 51876037) and the Key Research and Development Program of Jiangsu Province, China (No. BE2017159).
- Sulzer G., Verfahren zur erzeugung von arbeit aus warme (Method for producing work from heat). Swiss Patent 269599, 1948.Google Scholar
- Angelino G., Carbon dioxide condensation cycles for power production. Journal of Engineering for Power 1968, 90(3): 287–295.Google Scholar
- Dostál V., Driscoll M.J., Hejzlar P., A Supercritical carbon dioxide cycle for next generation nuclear reactors. Massachusetts Institute of Technology, 2004.Google Scholar
- Persichilli M., Held T., Hostler S., et al., Transforming waste heat to power through development of a CO2-based-power cycle. Electric Power Expo, 2011: 10–12.Google Scholar
- Wright S., Davidson C., Scammell W., Thermo-economic analysis of four sCO2 waste heat recovery power systems//Fifth International SCO2 Symposium, San Antonio, TX, 2016, pp.: 28–31.Google Scholar
- Huang Y., Wang J., Zang J., Liu G., Research activities on supercritical carbon dioxide power conversion technology in China. In: ASME, editor. ASME turbo expo 2014: turbine technical conference and exposition, Dusseldorf. DOI: https://doi.org/10.1115/GT2014-26049.
- White C., Shelton W., Dennis R., An assessment of supercritical CO2 power cycles integrated with generic heat sources//The 4th International Symposium-Supercritical CO2 Power Cycles. 2014.Google Scholar
- Wang X., Wu Y., Wang J., Dai Y., Xie D., Thermoeconomic analysis of a recompression supercritical CO2 cycle combined with a transcritical CO2 cycle. In: ASME turbo expo 2015: turbine technical conference and exposition. Montreal: American Society of Mechanical Engineers; 2015. DOI: https://doi.org/10.1115/GT2015-42033.Google Scholar
- Lockwood T., Techno-economic analysis of PC versus CFB combustion technology. IEA Clean Coal Centre, Report CCC/226, London, UK, 2013.Google Scholar
- Allam R.J., Fetvedt J.E., Forrest B.A., et al., The oxy-fuel, supercritical CO2 Allam Cycle: New cycle developments to produce even lower-cost electricity from fossil fuels without atmospheric emissions//ASME Turbo Expo 2014: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2014: V03BT36A016-V03BT36A016. DOI: https://doi.org/10.1115/GT2014-26952.
- McClung A., Brun K., Delimont J., Comparison of supercritical carbon dioxide cycles for oxy-combustion//ASME Turbo Expo 2015: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2015: V009T36A006-V009T36A006. DOI: https://doi.org/10.1115/GT2015-42523.
- Wall T., Liu Y., Bhattacharya S., A scoping study on Oxy-CFB technology as an alternative carbon capture option for Australian black and brown coals. ANLEC R&D, Monash University, 2012.Google Scholar
- Shelton W.W., Weiland N., White C., et al., Oxy-coal-fired circulating fluid bed combustion with a commercial utility-size supercritical CO2 power cycle//The 5th International Symposium-Supercritical CO2 Power Cycles, San Antonio, TX. 2016.Google Scholar