Patent ID: 8887505

Claim:
A carbon dioxide recovery system that recycles a carbon dioxide absorbent, even when an operation load of a boiler or a steam turbine in a power generation system fluctuates, comprising: a high-pressure turbine; a medium-pressure turbine; a low-pressure turbine as the steam turbine; a boiler to generate steam for driving the turbines; a carbon dioxide recovery unit including a carbon dioxide absorber that absorbs and reduces carbon dioxide in combustion flue gas discharged from the boiler by means of a carbon dioxide absorbent, and a carbon dioxide regenerator that treats a carbon dioxide absorbent having absorbed carbon dioxide and regenerates a regenerated carbon dioxide absorbent; a first steam extraction line to extract steam from an inlet of the low-pressure turbine; a first auxiliary turbine that is coupled to the first steam extraction line via a first valve and recovers power by means of the steam thus extracted; a first steam delivery line to supply discharged steam discharged from the first auxiliary turbine to a reboiler as a heat source for causing the carbon dioxide regenerator to treat the carbon dioxide absorbent having absorbed carbon dioxide for regeneration; a bypass line that bypasses the first auxiliary turbine and connects between the first steam extraction line and the first steam delivery line via a second valve; a controller for receiving operation load information and, based on the load information, for inputting information on the flow rate of steam supplied to the inlet of the low-pressure turbine and to the first auxiliary turbine, that controls driving of the first auxiliary turbine and the first and second valves while keeping pressure of the discharged steam to be supplied to the reboiler within an optimum tolerance range for the reboiler in response to a fluctuation in an operation load of the boiler or steam turbines of a power generation system; a second steam extraction line to extract the steam from an inlet of the medium-pressure turbine; a second auxiliary turbine that is coupled to the second steam extraction line and recovers power by means of the steam thus extracted; and a second steam delivery line to supply discharged steam discharged from the second auxiliary turbine to the reboiler as a heat source.