7. Smoke bypass

This component is not essential to the operation of a combined-cycle power plant. If this system has been selected, it is installed on the flue gas exhaust duct at the combustion turbine outlet, before the recovery boiler. Combustion turbine gases are directed either to the recovery boiler or to the bypass stack via a system of dampers (see § 1.2 of article [BE 8 905] ). This system adds complexity to the installation, but may prove indispensable when a minimum power supply guarantee has been contracted. Thanks to the flue gas bypass, the combustion turbine can continue to generate electricity even when damage renders the water-steam cycle unavailable. Repair work on the steam turbine or cold source is then possible even with the combustion turbine in operation. Interventions on the recovery boiler...