Gas and steam turbine plant and corresponding process

The gas and steam turbine plant comprises a gas turbine (1), and a fuel system (8) upstreams a combustion chamber (3) of the gas turbine. The fuel system has a gasification unit (10) for fossil fuel. A flushing line (42) is provided, which is joined between the gasification unit and a saturator (21) in a gas pipe (9). An independent claim is also included for a method for rinsing a portion of a fuel system of a gas and steam turbine plant.