Near-zero emission IGCC system coupled with low-energy chemical looping nitrogen substitution

Amidst global efforts toward cleaner energy, Integrated Gasification Combined Cycle (IGCC) technology offers a transformative approach to converting coal into electricity with reduced environmental impact. However, IGCC faces challenges such as chemical energy loss during gasification and high energy demands for carbon capture. To address these, the authors propose a sequential coal gasification system integrated with chemical looping nitrogen substitution (CLNS). This innovative system divides the traditional gasification process into two stages and fully utilizes residual flue gas heat to minimize energy loss. CLNS efficiently separates nitrogen from the air, producing a mixture of O2-CO2, which replaces air as the oxidizing agent in the gas turbine. Then the system captures CO2 by condensing the flue gas, similar to oxygen-enriched combustion. Compared to conventional coal-water slurry gasification with pre-combustion CO2 capture, the proposed system achieves a power generation efficiency of 45.66 % and an exergy efficiency of 43.99 %, reflecting improvements of 8.08 % and 7.62 %, respectively. Additionally, the Levelized Cost of Electricity (LCOE) is reduced by 8.38 %–136.16 $/MWh, positioning this system as a promising solution for near-zero emission power generation.