Patent ID: 8529678
Filing Date: 2013-09-10
Classification: B01D,Y02C

Abstract:
1. A CO 2 recovery system including an absorption tower that receives CO 2 -containing gas and CO 2 -absorbing solution, and causes the CO 2 -containing gas to come in contact with the CO 2 -absorbing solution to produce CO 2 rich solution, and a regeneration tower, including an upper-portion regeneration tower and a lower-portion regeneration tower, that receives the rich solution and produces lean solution from the rich solution by removing CO 2 from the rich solution, the CO 2 recovery system comprising: a bottom lean-solution extraction path that extracts lean solution that accumulates near a bottom portion of the regeneration tower from a first point of the regeneration tower and returns extracted lean solution to a second point of the regeneration tower that is downstream of the first point; a regeneration heater arranged in the bottom lean-solution extraction path and heats the lean solution in the bottom lean-solution extraction path with saturated steam thereby producing steam condensate from the saturated steam; a steam-condensate heat exchanger that heats, with the steam condensate, either one of a semi-lean-solution supply member that extracts semi-lean solution from a ninth point of the upper-portion regeneration tower and returns extracted semi-lean solution to a tenth point of the upper-portion regeneration tower that is downstream of the ninth point; a rich-solution supply member that conveys the rich solution from the absorption tower to the regeneration tower; a first branching node provided in the rich-solution supply member and that branches the rich-solution supply member into a first rich-solution supply member and a second rich-solution supply member; a lean-solution supply member that extracts the lean solution from the regeneration tower and conveys extracted lean solution to the absorption tower; a lean-solution heat exchanger that is provided in the first rich-solution supply member and the lean-solution supply member, and heats the rich solution in the first rich-solution supply member with the lean solution in the lean-solution supply member; a semi-lean-solution heat exchanger that is provided in the second rich-solution supply member and the semi-lean-solution supply member, and heats the rich solution in the second rich-solution supply member with the semi-lean solution in the semi-lean-solution supply member; a solution supply path that supplies the rich solution heated in the semi-lean-solution heat exchanger to downstream of the lean-solution heat exchanger in the first rich-solution supply member; a second lean-solution heat exchanger arranged in the first rich-solution supply member and the lean-solution supply member downstream of where the solution supply path conveys the rich solution in the first rich-solution supply member; and a second branching node provided in the semi-lean-solution extraction path downstream of the semi-lean-solution heat exchanger and that branches the semi-lean-solution extraction path into a first semi-lean-solution extraction path and a second semi-lean-solution extraction path, wherein the steam-condensate heat exchanger is arranged in the first semi-lean-solution extraction path and heats the semi-lean solution in the first semi-lean-solution extraction path with the steam condensate, and one end of the second semi-lean-solution extraction path is connected to a middle stage portion of the absorption tower.