Carbon dioxide recovery system and method of operating the carbon dioxide recovery system

摘要

A carbon dioxide recovery system comprises an absorption tower 11 making carbon dioxide absorbed in an absorption liquid and discharging a rich liquid as the absorption liquid having absorbed the carbon dioxide. The system also includes a regeneration tower 14 which discharges a regeneration tower exhaust gas containing the carbon dioxide and a water vapor released from the rich liquid and a lean liquid which is the absorption liquid having a carbon dioxide dissolved concentration lower than that of the rich liquid. The system further includes a condensing portion 21, 22 separating the regeneration tower exhaust gas into the carbon dioxide and condensed water, a mixing portion 25 mixing the condensed water and a supplied amine and producing a supplied amine aqueous solution in which the supplied amine is dissolved. There is also a supplying portion 33 supplying the supplied amine into the absorption liquid by mixing the supplied amine aqueous solution in the absorption liquid. Preferably the system treats combustion exhaust gas with a supplied solid or liquid amine such as piperazine. Advantageously the lowering of amine concentration of the absorption liquid in the system is suppressed.