Thermodynamic analysis of combined cycle gas turbine power plant with postcombustion CO₂ capture and exhaust gas recirculation

Natural gas is expected to make up a significant proportion of the future global energy mix. Therefore, reducing greenhouse gas emissions from gas-fired processes is very essential for most countries, before emission reduction targets can be met. This article aims to carry out thermodynamic analysis of combined cycle gas turbine power plant with post-combustion CO₂ capture through modelling and simulation. The combined cycle gas turbine power plant and the CO₂ capture plant were simulated in Aspen Plus ^®. The combined cycle gas turbine power plant model was validated with simulation data from GateCycle^® and the CO₂ capture plant model was validated with experimental data from the pilot plant at the University of Texas at Austin. The CO₂ capture plant was scaled up from pilot plant to commercial scale to process flue gas from a 250MWe combined cycle gas turbine power plant. The integrated model for combined cycle gas turbine and CO₂ capture plant was further used for performance study. Exhaust gas recirculation has been proposed to increase CO₂ concentration in flue gas and reduce the flue gas flow rate. Its effect on combined cycle gas turbine power plant performance and capture plant sizing has been investigated. The analysis indicated that exhaust gas recirculation can reduce penalty on thermal efficiency without any major modification to the original power plant.