Tech-economic assessment of chemical looping combustion coupled with the combined supercritical CO2 Brayton cycle and ORC for power generation

Abstract

BackgroundChemical looping combustion (CLC) has attracted wide interests with high-efficiency and near-zero energy penalty carbon capture. However, the low-pressure operation of the most adopted circulating fluidized-bed reactors restricts the application of the downstream combined (gas-steam turbines) cycle, leading to an unsatisfying system efficiency. For this reason, this paper integrates atmosphere CLC with the combined recompression supercritical CO2 Brayton cycle and organic Rankine cycle (CLC-sCO2-ORC) for power generation. MethodsThe proposed system was modeled and simulated with Aspen Plus to manifest its tech-economic feasibility. Significant findingsThe sensitive analysis suggests that the optimal sCO2 turbine inlet temperature and pressure are 700 °C and 280 bar, respectively, and the recompression split fraction is 0.72. Under the optimal condition, the energy efficiency of 51.79% is superior to the conventional natural gas combined cycle (NGCC) (49.38%) and other CLC-based power generation technology (50.13%). Exergy analysis was also performed to put forward some improvement strategies. Importantly, CLC operating temperature imposes nearly no impact on exergy loss. Besides, the economic indicator, levelized cost of electricity (LCOE) is supposed to be profitable at 79.17 $/MWh, which is lower than that of other CLC-based power generation system (83.12 $/MWh).