A CO 2 recovery system includes: a CO 2 absorber that transports flue gas with CO 2 into contact with a CO 2 absorbent to remove the CO 2 and discharges a rich solution that has absorbed the CO 2 ; an absorbent regenerator that separates the CO 2 from the rich solution to regenerate the CO 2 absorbent as a lean solution; a gas discharge line where a CO 2 entrained gas from the absorbent regenerator is discharged; a reflux water drum that produces reflux water by separating CO 2 and water from the CO 2 entrained gas; a separation-gas discharge line where the separated CO 2 is discharged; a compressor that compresses the separated CO 2 gas; a condensate water drum that forms compressor condensate water by separating water from the compressed CO 2 gas to form compressor condensate water; and a compressor-condensate water line that supplies the compressor condensate water as in-system or out-of-system supply water.
1. A CO 2 recovery system comprising:
a CO 2 absorber that:
transports flue gas comprising CO 2 into contact with a CO 2 absorbent to remove the CO 2 from the flue gas, and
discharges a rich solution that has absorbed the CO 2;
an absorbent regenerator that separates the CO 2 from the rich solution to regenerate the CO 2 absorbent as a lean solution;
a gas discharge line where a CO 2 entrained gas, discharged from a top portion of the absorbent regenerator, is discharged;
a reflux water drum, disposed in the gas discharge line, that produces reflux water by separating the CO 2 and water from the CO 2 entrained gas;
a separation-gas discharge line where the CO 2 separated by the reflux water drum is discharged;
a compressor disposed in the separation-gas discharge line that compresses the separated CO 2 gas;
a condensate water drum, disposed in the separation-gas discharge line, that produces compressor condensate water by separating the water from the compressed CO 2 gas; and
a compressor-condensate water line, connected to the condensate water drum, that supplies the compressor condensate water as in-system supply water or out-of-system supply water; and
a reclaiming device that regenerates the CO 2 absorbent, wherein:
the reclaiming device is connected to an end portion of the compressor-condensate water line and includes:
a branch line that draws a part of the lean solution as lean drawn liquid,
a reclaimer that takes in and reserves the lean drawn liquid,
an alkaline-agent supply unit that supplies an alkaline agent into the reclaimer via an alkaline supply line,
a reflux-water supply line that supplies the reflux water into the reclaimer,
a recovery-steam discharge line that supplies recovery steam discharged from the reclaimer to a bottom portion side of the absorbent regenerator, and
a heating unit that heats an inside of the reclaimer.
2. The CO 2 recovery system according to claim 1 , wherein the in-system supply water is reclaiming water for the reclaiming device.
3. The CO 2 recovery system according to claim 1 , wherein
the reclaiming device is subjected to, after regeneration of the CO 2 absorbent is completed:
an early-stage recovery operation that:
closes the branch line and stops supplying the lean drawn liquid into the reclaimer, and
recovers a CO 2 absorption component that forms the CO 2 absorbent, and
a late-stage recovery operation that:
closes the reflux-water supply line to stop supplying the reflux water into the reclaimer, and
performs finishing recovery of the CO 2 absorption component using the compressor condensate water.
4. The CO 2 recovery system according to claim 1 , further comprising a flash drum that separates gas from the compressor condensate water to be supplied into the reclaiming device.
5. The CO 2 recovery system according to claim 1 , further comprising:
an inlet thermometer that measures a temperature of the flue gas to be supplied to the CO 2 absorber;
an outlet thermometer that measures a temperature of emission gas discharged from the CO 2 absorber, wherein
the CO 2 recovery system uses the compressor condensate water as the out-of-system supply water by regulating the temperature of the emission gas to be lower than the temperature of the flue gas.
6. A method of circulating and reusing, with a CO 2 absorber, a CO 2 absorbent with the CO 2 removed by an absorbent regenerator, the CO 2 absorber brings flue gas comprising the CO 2 into contact with the CO 2 absorbent to remove the CO 2 and discharges a rich solution that has absorbed the CO 2 , the absorbent regenerator separates the CO 2 from the rich solution to regenerate the CO 2 absorbent as a lean solution, the method comprising:
separating, by a reflux water drum, the CO 2 and water from a CO 2 entrained gas discharged from a top portion of the absorbent regenerator to produce reflux water;
compressing the CO 2 separated by the reflux water drum; and
separating water from the compressed CO 2 gas to form compressor condensate water; and
conducting a reclaimer operation of the CO 2 absorbent by using the reflux water and the compressor condensate water in a reclaiming device, wherein
the compressor condensate water is used as in-system supply water or out-of-system supply water, and
conducting the reclaimer operation includes:
after regenerating of the CO 2 absorbent is completed,
an early-stage recovery operation that stops supplying a lean drawn liquid that is part of the lean solution into the reclaiming device, and that recovers a CO 2 absorption component constituting the CO 2 absorbent, and
a late-stage recovery operation that stops supplying the reflux water into the reclaiming device, and that performs finishing recovery of the CO 2 absorption component constituting the CO 2 absorbent using the compressor condensate water.