Carbon dioxide separating and capturing system and method of operating same

A method of operating a carbon dioxide separating and capturing system, comprising:

• introducing a first gas containing carbon dioxide to an absorption tower;
• allowing the first gas to contact with an absorption liquid to allow the absorption liquid to absorb the carbon dioxide in the first gas in the absorption tower, discharging a first rich liquid which is the absorption liquid having absorbed the carbon dioxide, and discharging a second gas whose carbon dioxide content is lower than a carbon dioxide content of the first gas;
• dividing the first rich liquid into a second rich liquid and a third rich liquid;
• causing the absorption liquid to release a third gas containing the carbon dioxide in a regeneration tower, and discharging a lean liquid whose carbon dioxide concentration is lower than a carbon dioxide concentration of the first rich liquid;
• heating the absorption liquid in the regeneration tower by a reboiler using steam;
• heating the second rich liquid fed to the regeneration tower by a first heat exchanger using, as a heat source, the lean liquid fed from the regeneration tower to the absorption tower;
• and
• heating the third rich liquid fed to the regeneration tower by a second heat exchanger using, as a heat source, water discharged from the reboiler.