Patent ID: 7938889

Claim:
A CO 2 recovery system comprising: an absorption tower that causes CO 2 -containing exhaust gas to come in contact with a CO 2 -absorbing solution and removes CO 2 ; a regeneration tower that regenerates a rich solution that has absorbed CO 2 by heat exchange; and a separation drum that condensates steam in CO 2 gas with the steam released from the regeneration tower and separates water, wherein a lean solution produced by removing CO 2 from the rich solution is reused in the absorption tower, wherein the absorption tower includes a CO 2 -recovery unit that causes the CO 2 -containing exhaust gas to come in contact with the CO 2 -absorbing solution and absorbs CO 2 contained in the exhaust gas; a washing unit that is arranged in an upper side of the CO 2 -recovery unit, cools CO 2 -removed exhaust gas after CO 2 is removed, and recovers the CO 2 -absorbing solution accompanying the CO 2 -removed exhaust gas; and a condensed-water receiver that is arranged in a lower side of the washing unit and collects condensed water containing a low-concentration CO 2 -absorbing solution in the washing unit, wherein a filtration membrane apparatus is provided on a lean-solution branch line branched from a lean solution supply line that supplies the lean solution from the regeneration tower to the absorption tower, a cleaning-water supply line that supplies the condensed water containing the low-concentration CO 2 -absorbing solution as cleaning water is provided on the lean-solution branch line, solid content remaining in the lean solution is filtered by the filtration membrane apparatus using a filter, and the filter is cleaned using the cleaning water and the low-concentration CO 2 -absorbing solution used for the cleaning is returned into the absorption tower.