PLANT AND COMBUSTION EXHAUST GAS PROCESSING METHOD

This plant is provided with: a gas turbine 11; an exhaust heat recovery device 15 which includes a main exhaust heat recovery boiler 13 for subjecting the thermal energy of combustion exhaust gas 12 from the gas turbine 11 to heat-exchange in a main heat-exchange unit 13A and generating main steam S10, and a sub-exhaust heat recovery boiler 14 which is installed independently of the main heat-exchange unit 13A, subjects the thermal energy from the combustion exhaust gas 12 after a partial heat-exchange in the main heat-exchange unit 13A of the mam exhaust heat recovery boiler 13 to heat-exchange in a sub-heat-exchange unit 14A, and generates sub-steam S20; a main steam turbine 16 which is driven with the main steam S10 generated in the main exhaust heat recovery boiler 13; a CO2 recovery device 50 including a reboiler for recovering CO2 contained in the combustion exhaust gas 12 discharged from the exhaust heat recovery device 15; and a first reboiler heat supply line L21 for introducing the sub-steam S20 generated in the sub-exhaust heat recovery boiler 14 into the reboiler 55.