Gas Turbine Combined Cycle Optimized for Postcombustion Carbon Capture

This paper describes a gas turbine combined cycle (GTCC) power plant system, which addresses the three key design challenges of postcombustion CO₂ capture from the stack gas of a GTCC power plant using aqueous amine-based scrubbing method by offering the following: (i) low heat recovery steam generator (HRSG) stack gas temperature, (ii) increased HRSG stack gas CO₂ content, and (iii) decreased HRSG stack gas O₂ content. This is achieved by combining two bottoming cycle modifications in an inventive manner, i.e., (i) high supplementary (duct) firing in the HRSG and (ii) recirculation of the HRSG stack gas. It is shown that, compared to an existing natural gas-fired GTCC power plant with postcombustion capture, it is possible to reduce the CO₂ capture penalty—power diverted away from generation—by almost 65% and the overall capital cost ($/kW) by about 35%.