Method for separating carbon dioxide and apparatus for separating carbon dioxide

A carbon dioxide separation method comprising the steps of:

• feeding a mixed gas that contains at least carbon dioxide and water vapor to a carbon dioxide separation membrane that contains a hydrophilic resin and a carbon dioxide carrier;
• separating, from the mixed gas, a permeation gas that contains the carbon dioxide by use of the carbon dioxide separation membrane;
• adjusting temperature of gas which contacts the carbon dioxide separation membrane so that a temperature difference between the mixed gas fed to the carbon dioxide separation membrane and the permeation gas which has permeated the carbon dioxide separation membrane is not lower than 0° C. and not higher than 20° C.;
• and
• adjusting pressure of the permeation gas which has permeated the carbon dioxide separation membrane,
• the pressure of the permeation gas which has permeated the carbon dioxide separation membrane and water vapor partial pressure in the mixed gas fed to the carbon dioxide separation membrane satisfying the following formula (1):
• 2.5 kPaA<(pressure of permeation gas)<(water vapor partial pressure in mixed gas) (1).