Combustion exhaust gas treatment system and combustion exhaust gas treatment method

The invention provides a combustion exhaust gas treatment system and a combustion exhaust gas treatment method. The combustion exhaust gas treatment system comprises a heat exchanger (A) for recovering heat in combustion exhaust gas to a heating medium; an absorption tower for contacting the combustion exhaust gas with an absorbent so as to absorbe the CO2 contained in the combustion exhaust gas to the absorbent; a heat exchanger (B) for imparting the heat recovered by the heating medium to the absorbent that has absorbed CO2; a regeneration tower for expelling from the absorbent that has absorbed CO2, thereby regenerating the absorbent; a flash tank for flash-evaporating the regenerated absorbent; and a heat exchanger (E) for transferring heat from the regenerated absorbent to the absorbent that has absorbed CO2. The combustion exhaust gas treatment system can supply absorbent that has absorbed CO2 from the absorption tower to the regeneration tower, via the heat exchanger (E) and heat exchanger (B) in this