In the present paper the performance of a hot windbox repowering steam power plant are evaluated.
A methodology has been developed to determine the mass flow rate range of gas turbine exhaust gas injected into a steam generator of an existing steam power plant.
The study allowed to evaluate the performance of the repowered plant for different gas turbine available on the market.
By utilizing the same methodology, this repowering solution was also investigated employing an intercooler gas turbine that, in the state of art, may be realistically proposed.
It resulted that the hot windbox repowering with Brayton cycle gas turbine supplies a considerably higher power output and efficiency than those of the steam power plant before the repowering.
The employing of an intercooled gas turbine provides further improvements of power and efficiency with respect to the repowered plant using the Brayton cycle gas turbine.