Gas Turbine Performance Using Carbon Dioxide as Working Fluid in Closed Cycle Operation

Abstract

The world’s main atmospheric “greenhouse gas” is carbon dioxide (CO2). The CO2 content of the atmosphere continues to rise due to increasing world demand for energy, and thus further means are needed to achieve its abatement. Most gas turbine powered electricity generating plants use hydro-carbon fuels and this inevitably produces CO2 in the engine exhaust. This paper discusses a scheme for concentrating the gas turbine exhaust CO2, thus facilitating its extraction. The scheme is a gas turbine operating synchronously in closed cycle, with CO2 as the working fluid. The additional CO2 and water produced in the combustion process are removed continuously. CO2 and air have substantially different gas properties. This significantly affects the performance of the gas turbine. It is shown that any gas turbine designed to use air, and operating synchronously, would need considerable modifications to its compressor and combustion systems to use carbon dioxide as its working fluid.