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A CO 2 recovery unit and a CO 2 recovery method capable of having an excellent CO 2 absorption rate and saving energy are provided. A CO 2 recovery unit of the invention includes: a CO 2 absorber which includes an upper CO 2 absorption unit obtaining a CO 2 absorbent by causing a flue gas containing CO 2 to contact a CO 2 absorbent and a lower CO 2 absorption unit obtaining a CO 2 absorbent by causing the CO 2 absorbent to contact a flue gas containing CO 2 ; a CO 2 absorbent regenerator which obtains the CO 2 absorbent by heating the CO 2 absorbent a thermometer which measures a temperature of the CO 2 absorbent supplied from the CO 2 absorber to the CO 2 absorbent regenerator; and a control device which controls a temperature of the CO 2 absorbent supplied to the lower CO 2 absorption unit based on the temperature of the CO 2 absorbent measured by the thermometer.
1. A CO 2 recovery method comprising:
obtaining a first CO 2 absorbent by causing a CO 2 containing gas to be treated to contact a CO 2 absorbent in a first CO 2 absorption unit of a CO 2 absorber so that CO 2 contained in the gas to be treated is absorbed to the CO 2 absorbent and obtaining a second CO 2 absorbent by causing the first CO 2 absorbent to contact the CO 2 containing gas to be treated in a second CO 2 absorption unit of the CO 2 absorber so that CO 2 contained in the gas to be treated is absorbed to the first CO 2 absorbent;
regenerating the CO 2 absorbent by heating the second CO 2 absorbent in a CO 2 absorbent regenerator so that CO 2 is discharged from the CO 2 absorbent; and
measuring a temperature of the second CO 2 absorbent supplied from the CO 2 absorber to the CO 2 absorbent regenerator and controlling a temperature of the first CO 2 absorbent supplied to the second CO 2 absorption unit based on the measured temperature of the second CO 2 absorbent, wherein
controlling the temperature of the first CO 2 absorbent supplied to the second CO 2 absorption unit such that the measured temperature of the second CO 2 absorbent is in a range of 62° C. to 67° C.,
wherein a CO 2 partial pressure of the CO 2 containing gas to be treated is in a range of 50 kPa to 200 kPa.
2. The CO 2 recovery method according to claim 1 ,
wherein the temperature of the first CO 2 absorbent supplied to the second CO 2 absorption unit is controlled so that the temperature is in the range of 50° C. to 60° C.
3. The CO 2 recovery method according to claim 1 ,
wherein a ratio (the first CO 2 absorption unit:the second CO 2 absorption unit) between a filling material charging height in the first CO 2 absorption unit and a filling material charging height in the second CO 2 absorption unit is in the range of 1:3 to 3:1.