Thermodynamic analysis and techno-economic evaluation of an integrated natural gas combined cycle (NGCC) power plant with post-combustion CO2 capture

A new integrated system with power generation and CO2 capture aiming to reduce de-carbonization penalty is proposed in this study. In the new system, four measures are adopted, as follows: (1) recycling part of exhausted gas from gas turbine to increase the CO2 concentration in flue gas, (2) mixing a portion of condensate water from reboiler with the extracted steam to utilize the superheat degree of the extracted steam, (3) compressing the CO2 stream at the top of stripper to recover the latent heat for sorbent regeneration, and (4) introducing a transcritical CO2 cycle to utilize the sensible heat in flue gas to generate electricity. All the cases are simulated by the process simulation software, Honeywell's UniSim Design Suit R400. Thermodynamic and preliminary tech-economic analyses are conducted in this paper. As a result, the power output of the new integrated system is 26.15 MW greater than that of de-carbonization natural gas combined cycle (NGCC) power plant without integration. The efficiency penalty of CO2 capture is expected to decrease by 2.63%-points. Meanwhile, the investment increase of the new system is 60.17 M$ which is only 4.66% larger than that of the de-carbonization power plant without integration. Finally, the cost of electricity and the cost of CO2 avoided are reduced by 8.66% and 27.46%, respectively.