Performance and Cost Analysis of a Novel Gas Turbine Cycle With CO2 Capture

Abstract

In this paper, a new gas turbine cycle with integrated post-combustion CO2 capture is presented. The concept advantageously uses an intercooled gas turbine in combination with exhaust gas recirculation to enable CO2 separation at elevated concentration and pressure. Therefore, less energy is required for the CO2 separation process. In addition, due to the reduced volume flow entering the CO2 separation unit, the costs of the CO2 separation equipment are significantly reduced. The performance and cost of CO2 avoided of the power cycle have been analyzed. The results show that the concept is able to reach high CO2 capture rates of 80% and above. When accounting for CO2 capture and compression, nearly 50% (LHV) combined cycle net efficiency is obtained based on an existing medium scale intercooled gas turbine. Furthermore, the cycle has an even higher efficiency potential if applied to larger intercooled gas turbine combined cycles in the future. Using CO2 separation membrane technology which is currently under development, the cost of CO2 avoided is estimated at 31 $/tCO2 based on a medium scale intercooled gas turbine. A future scaled-up configuration based on a large-frame intercooled gas turbine has the potential to meet 30 $/tCO2 cost of CO2 avoided.

Performance evaluation of an Organic Rankine Cycle fed by waste heat recovered from CO2 capture section

“…A first step that has been proposed for NGCC in order to reduce the high exhaust volumes and to increase the low CO2 concentration in the flue gas is the exhaust gas recirculation (EGR). EGR leads to a reduction of both specific energy demand of the separation process and costs associated with the capture unit [17][18][19]. Studies show that a percentage of exhaust gas recycled back to the GT ranging between 30 and 50% cause a small impact on the gas turbine turbomachinery components [20].…”