Pressurized oxy-fuel combustion with sCO2 cycle and ORC for power production and carbon capture

Abstract

The pressurization of oxy-fuel combustion presents the opportunity to recuperate more latent heat from the flue gas within the boiler. This study proposed a coal-fired pressurized oxy-fuel combustion plant coupled with the sCO2 Brayton cycle for simultaneous power production and carbon capture. Two configurations, i.e., sCO2 recuperator split and sCO2 bottom cycle, are conceived to fully exploit the flue gas heat from the boiler. Waste heat from various sources, including the air separation unit, the CO2 compression and purification unit and the sCO2 cycle, are recuperated by the organic Rankine cycle (ORC) to augment the net power efficiency. Sensitive analyses, including the turbine parameters, the recuperator split ratio, and the ORC parameters, are conducted to optimize the design and operation conditions of the plant. The plant net power efficiency ranges between 39.4 % and 42.9 %, inclusive of CO2 compression. The levelized cost of electricity (LCOE) is calculated, and the LCOE results are in the range of 101.60 $/MWh and 106.07 $/MWh for different configurations. These findings suggest the system's viability for future coal-fired plant with carbon capture.

Keywords

• Coal-fired power plant
• sCO2 Brayton cycle
• Organic Rankine cycle
• Carbon capture
• Efficiency