Abstract
A closed-loop, indirect, supercritical Carbon Dioxide (sCO2) power cycle is attractive for fossil-fuel, solar thermal and nuclear applications owing to its ability to achieve higher efficiency, and compactness. Commercial Gas Turbines (GT’s) are optimised to yield maximum performance with a conventional steam Rankine cycle. In order to explore the full potential of a sCO2 cycle the whole plant performance needs to be considered. This study analyses the maximum performance and cost of electricity for five sCO2 cascaded cycles. The plant performance is improved when the GT pressure ratio is considered as a design variable to a GT to optimise the whole plant performance. Results also indicate that each sCO2 Brayton cycle considered, attained maximum plant efficiency at a different GT pressure ratio. The optimum GT pressure ratio to realise the maximum cost reduction in sCO2 cycle was higher than the equivalent steam Rankine cycle. Performance maps were developed for four high efficient cascaded sCO2 cycles to estimate the specific power and net efficiency as a function of GT turbine inlet temperature and pressure ratio. The result of multi-objective optimisation in the thermal and cost (c$/kWh) domains and the Pareto fronts of the different sCO2 cycles are presented and compared. A novel sCO2 cycle configuration is proposed that provides ideal-temperature glide at the bottoming cycle heat exchangers and the efficiency of this cycle, integrated with a commercial SGT5-4000F machine in lieu of a triple-pressure steam Rankine cycle, is higher by 1.4 percentage point.
Highlights
This paper introduces a general concept for integrating sCO2 cycles with Combined Cycle Power Plant (CCPP) and demonstrates the maximum potential of sCO2 cycles without being limited to any commercially available Gas Turbine (GT)
This study considered five sCO2 cascade cycles in lieu of a conventional steam Rankine cycle in a CCPP with an industrial SGT54000F class heavy-duty GT and analysed using multi-objective optimisation with regard to thermal and economic performance
Simulations were performed for several GT Turbine Inlet Temperature (TIT) to explore the change in performance for different sCO2 cycle configurations
Summary
The UK is committed to reducing greenhouse gas emissions by at least 80% of 1990 levels by 2050 [1] Meeting such a rigorous carbon emission reduction goal requires significant technological breakthroughs in the power generation industries. New thermodynamic cycles that enhance CO2 capture will become more practical if they can produce power at higher efficiency compared to conventional power technologies. The sCO2 Brayton cycle is considered suitable for different heat sources such as nuclear, solar thermal, and fossil-fuel. Several research studies have been done in the context of integrating an sCO2 Brayton cycle with nuclear and solar applications [4,5] limited attention has been given to cycle optimisation.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
