Gas Turbine Combined Cycle Optimized for Post-Combustion Carbon Capture

Abstract

This paper describes a gas turbine combined cycle (GTCC) power plant system, which addresses the three key design challenges of post-combustion 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 post-combustion capture, it is possible to reduce the CO2 capture penalty — power diverted away from generation — by almost 65 percent and the overall capital cost ($/kW) by about 35 percent.