Gas turbine assembly with post-combustion device for CO2 separation

The system (1) has a gas turbine (10) including a compressor stage (11) and an expansion stage (12). An exhaust gas line (20) guides a flow of exhaust gas exiting from the expansion stage during operation of the gas turbine. A carbon-di-oxide separation device (30) is fluid-technically connected with the gas line for separation of part of carbon-di-oxide contained in the exhaust gas. An afterburner device (40) is switched into the gas line between the gas turbine and the separation device, where the afterburner device post-burns fuel i.e. fossil fuel, under the requirement. An independent claim is also included for a method for operating a gas turbine system.