Carbon dioxide recovering apparatus and method for operating the same

Abstract

According to one embodiment, a carbon dioxide recovering apparatus includes a flow distributor dividing the first rich solution discharged from an absorbing tower into a second rich solution and a third rich solution, a reheat exchanger heating the second rich solution with a lean solution discharged from a releasing tower as a heat source, a heating unit heating the third rich solution with a carbon dioxide containing steam to be released from the releasing tower as a heat source, a gas-liquid separator separating the carbon dioxide containing steam used to heat the third rich solution into carbon dioxide and condensate water, a measuring unit measuring an amount of the condensate water in the gas-liquid separator, and a controller. The controller controls a flow dividing ratio in the flow distributor based on a change in the amount of the condensate water measured by the measuring unit.

What is claimed is: 
     
         1 . A carbon dioxide recovering apparatus comprising:
 an absorbing tower bringing the flue gas containing carbon dioxide into contact with an absorbing solution that absorbs carbon dioxide and generating and discharging a first rich solution that has absorbed carbon dioxide;   a flow distributor dividing the first rich solution into a second rich solution and a third rich solution;   a releasing tower heating the second rich solution and the third rich solution, causing carbon dioxide containing steam to be released to generate a lean solution, discharging the lean solution, and returning the lean solution to the absorbing tower;   a reheat exchanger heating the second rich solution with the lean solution discharged from the releasing tower as a heat source;   a heating unit heating the third rich solution before becoming the lean solution with the carbon dioxide containing steam to be released from the releasing tower as a heat source;   a gas-liquid separator separating the carbon dioxide containing steam used to heat the third rich solution into carbon dioxide and condensate water;   a measuring unit measuring an amount of the condensate water in the gas-liquid separator; and   a controller controlling a flow dividing ratio in the flow distributor based on a change in the amount of the condensate water measured by the measuring unit.   
     
     
         2 . The carbon dioxide recovering apparatus according to  claim 1 , wherein the controller raises a flow rate of the third rich solution from a predetermined value until the amount of the condensate water measured in the measuring unit becomes constant. 
     
     
         3 . The carbon dioxide recovering apparatus according to  claim 2 , further comprising a reboiler heating a stored solution in the releasing tower,
 wherein the controller controls a heat input amount in the reboiler after determination of the flow rate of the third rich solution so that a carbon dioxide recovering ratio in the absorbing tower may be a predetermined value.   
     
     
         4 . The carbon dioxide recovering apparatus according to  claim 3 , wherein the heating unit is a filling layer provided in the releasing tower, and
 wherein the filling layer is provided at a higher position than a part of the releasing tower to which the second rich solution is supplied.   
     
     
         5 . The carbon dioxide recovering apparatus according to  claim 3 , further comprising a joining unit joining the second rich solution heated in the reheat exchanger and the third rich solution heated in the heating unit and supplying them to the releasing tower. 
     
     
         6 . The carbon dioxide recovering apparatus according to  claim 2 , wherein the heating unit is a filling layer provided in the releasing tower, and
 wherein the filling layer is provided at a higher position than a part of the releasing tower to which the second rich solution is supplied.   
     
     
         7 . The carbon dioxide recovering apparatus according to  claim 2 , further comprising a joining unit joining the second rich solution heated in the reheat exchanger and the third rich solution heated in the heating unit and supplying them to the releasing tower. 
     
     
         8 . The carbon dioxide recovering apparatus according to  claim 1 , wherein the heating unit is a filling layer provided in the releasing tower, and
 wherein the filling layer is provided at a higher position than a part of the releasing tower to which the second rich solution is supplied.   
     
     
         9 . The carbon dioxide recovering apparatus according to  claim 1 , further comprising a joining unit joining the second rich solution heated in the reheat exchanger and the third rich solution heated in the heating unit and supplying them to the releasing tower. 
     
     
         10 . A method for operating a carbon dioxide recovering apparatus, comprising:
 introducing the flue gas containing carbon dioxide into an absorbing tower, bringing the flue gas containing carbon dioxide into contact with an absorbing solution that absorbs carbon dioxide, and generating and discharging a first rich solution that has absorbed carbon dioxide;   dividing the first rich solution into a second rich solution and a third rich solution;   heating the second rich solution with use of a lean solution;   heating the third rich solution with use of carbon dioxide containing steam;   in a releasing tower, releasing and separating steam containing carbon dioxide from the heated second rich solution and third rich solution to generate the carbon dioxide containing steam and the lean solution;   with use of a gas-liquid separator, separating the carbon dioxide containing steam used to heat the third rich solution into carbon dioxide and condensate water;   measuring an amount of condensate water in the gas-liquid separator; and   controlling a flow dividing ratio between the second rich solution and the third rich solution based on a change in the amount of the condensate water.   
     
     
         11 . The method for operating a carbon dioxide recovering apparatus according to  claim 10 , wherein a flow rate of the third rich solution is raised from a predetermined value, and the flow rate of the third solution is set to a flow rate when the amount of the condensate water becomes constant. 
     
     
         12 . The method for operating a carbon dioxide recovering apparatus according to  claim 11 , wherein a heat input amount in a reboiler connected to the releasing tower is controlled after determination of the flow rate of the third rich solution so that a carbon dioxide recovering ratio in the absorbing tower becomes a predetermined value. 
     
     
         13 . The method for operating a carbon dioxide recovering apparatus according to  claim 10 , wherein a flow rate of the third rich solution is lowered from a predetermined value, and the flow rate of the third rich solution is set to a flow rate when the amount of the condensate water does not fall in a certain range any more. 
     
     
         14 . The method for operating a carbon dioxide recovering apparatus according to  claim 13 , wherein a heat input amount in a reboiler connected to the releasing tower is controlled after determination of the flow rate of the third rich solution so that a carbon dioxide recovering ratio in the absorbing tower becomes a predetermined value.