8. Afterburner

This system consists of one or more burner banks positioned at the recovery boiler inlet ( [BE 8 905] figure 1). Post-combustion involves burning a flow of fuel (natural gas) in the recovery boiler before the first exchangers (high-pressure superheater and reheater), in order to raise the temperature of the flue gases supplied by the combustion turbine. This is made possible by the excess oxygen present in the flue gases. Combustion releases additional heat, making more energy available in the flue gases in the form of ambient temperature. This additional energy is used to produce more steam, thus increasing the power output of the steam turbine. On the other hand, post-combustion tends to reduce the plant's overall efficiency, as the natural gas consumption required for combustion has to be factored into...