Thermoeconomic and optimization analyses of direct oxy-combustion supercritical carbon dioxide power cycles with dry and wet cooling

Oxy-combustion supercritical CO₂ power cycles have the advantages of high-energy efficiency and near-zero pollutant emissions. Thus, these cycles are considered as an efficient way to reduce CO₂ emissions while maintaining economic growth. The major drawbacks of this technology include the lack of validated levelized cost of electricity (LCOE) studies; lower turbine inlet temperatures studies to accommodate the integration of various energy sources; solutions for the thermodynamic imbalance of the regenerator; and investigating the dry- versus the wet-cooling methods. These drawbacks are addressed in this paper by presenting comprehensive thermoeconomic and optimization analyses for three direct oxy-fuel sCO₂ power cycles in wet and dry-cooling conditions. The first cycle M1 is a direct oxy-fuel sCO₂ power cycle without preheater, the second cycle M2 integrates a preheater in parallel with the low-temperature recuperator of M1 while the third cycle M3 integrates a preheater in parallel with the high and low-temperature recuperators of M1. Results show that the integration of the preheater improves the thermal efficiency of M2 by 5.81% (wet), and 3.27% (dry), and of M3 by 13.27% (wet), and 6.58% (dry). The LCOE of M1 (without preheater) is higher than that of M2 by 10.8% (wet), and 5.7% (dry), and of M3 by 19.1% (wet), and 11.4% (dry). A minimum LCOE of 4.667¢/kWh_e is obtained for M3 (wet) and of 6.139¢/kWh_e for M3 (dry). At higher waste heat source temperature of 700 °C, the overall efficiency is improved by an average of 11% and the LCOE is reduced by 1.43 ¢/kWh_e.

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Published in: Energy Conversion and Management
License: http://creativecommons.org/licenses/by/4.0/
See article on publisher's website: https://dx.doi.org/10.1016/j.enconman.2021.114607