Steam turbine power plant and operation method thereof

Abstract

According to one aspect of the embodiment, a steam turbine power plant 10 is provided with a steam turbine system 20 which generates electricity by driving a steam turbine by the steam from a boiler 21 or the like which generates the steam by combustion heat, and a carbon dioxide recovery system 50 which recovers carbon dioxide contained in the combustion gas from the boiler 21 or the like. In the steam turbine system 20 , part of the steam having performed the expansion work in a high-pressure turbine 22 is introduced into a back-pressure turbine 27 . The steam introduced into the back-pressure turbine 27 performs the expansion work and partly supplied to the carbon dioxide recovery system 50 through a pipe 42 to heat an absorption liquid 90 in a regeneration tower 70.

1 . A steam turbine power plant, comprising:
 a steam turbine system, the steam turbine system comprises:
 a boiler comprising a superheater; 
 a first steam turbine into which main steam is introduced from the superheater of the boiler; 
 a reheater which reheats the steam discharged fluid the first steam turbine; 
 a second steam turbine into which the steam reheated by the reheater is introduced; 
 a third steam turbine into which the steam discharged from the second steam turbine is introduced; 
 a first electric generator which is driven by the third steam turbine; 
 a condenser which condensates the steam discharged from the third steam turbine into a condensate; 
 a feed water heater which heats the condensate to introduce into the boiler as feed water and a fourth steam turbine into which part of the steam discharged from the first steam turbine is introduced, and 
   a carbon dioxide recovery system, the carbon dioxide recovery system comprises:
 an absorption tower which absorbs the carbon dioxide contained in combustion gas from the boiler by an absorption liquid; 
 a regeneration tower which separates the carbon dioxide from the absorption liquid by heating the absorption liquid having absorbed the carbon dioxide by the steam discharged from the fourth steam turbine; and 
 a recovery apparatus which recovers the carbon dioxide separated by the regeneration tower. 
   
     
     
         2 . The steam turbine power plant according to  claim 1 ,
 wherein the second steam turbine is composed of two steam turbines, one of the two steam turbines is introduced with the steam obtained by reheating by the reheater the steam discharged from the first steam turbine, the other of the two steam turbines is introduced with the steam obtained by reheating by the reheater the steam discharged from the one of the two steam turbines, and the steam discharged from the other of the two steam turbines is introduced into the third steam turbine.   
     
     
         3 . The steam turbine power plant according to  claim 1 , further comprising,
 a second electric generator which is driven by the fourth steam turbine.   
     
     
         4 . The steam turbine power plant according to  claim 1 ,
 wherein the steam extracted from the fourth steam turbine is guided to the feed water heater.   
     
     
         5 . The steam turbine power plant according to  claim 1 , further comprising,
 a pressure regulating valve which adjusts the pressure of the steam discharged from the fourth steam turbine.   
     
     
         6 . The steam turbine power plant according to  claim 1 , further comprising,
 a flow rate regulating valve which introduces part of the steam discharged from the second steam turbine into a predetermined stage of the fourth steam turbine while adjusting the flow rate.   
     
     
         7 . The steam turbine power plant according to  claim 2 , further comprising,
 a flow rate regulating valve which introduces part of the steam discharged from the one of the two steam turbines into a predetermined stage of the fourth steam turbine while adjusting the flow rate.   
     
     
         8 . The steam turbine power plant according to  claim 1 , further comprising,
 a flow rate regulating valve which adjusts the flow rate of the steam, which is discharged from the fourth steam turbine and used to heat the absorption liquid in the regeneration tower based on the temperature of the absorption liquid in the regeneration tower.   
     
     
         9 . The steam turbine power plant according to  claim 1 , further comprising,
 a flow rate regulating valve which adjusts the flow rate of the steam, which is discharged from the fourth steam turbine and used to heat the absorption liquid in the regeneration tower based on the flow rate of the absorption liquid in the regeneration tower.   
     
     
         10 . An operation method of a steam turbine power plant comprising:
 a boiler having a superheater and a reheater;   a first steam turbine which is driven by steam introduced form the superheater of the boiler and discharges the steam to the reheater;   a second steam turbine which is driven by the steam from the reheater;   a third steam turbine which is driven by the steam discharged from the second steam turbine;   a fourth steam turbine which is driven by part of the steam discharged from the first steam turbine;   a condenser which condensates the steam discharged from the third steam turbine into a condensate;   a feed water heater which is disposed on a feed water system between the condenser and the boiler and heats the feed water guided from the condenser;   an absorption tower which has combustion gas guided into it from the boiler and an absorption liquid supplied into it and which absorbs the carbon dioxide contained in the combustion gas by the absorption liquid; and   a regeneration tower which diffuses the absorbed carbon dioxide by heating the absorption liquid having absorbed the carbon dioxide in the absorption tower,   wherein the steam extracted from the fourth steam turbine is used as a heat source for the feed water by the feed water heater, and the steam discharged from the fourth steam turbine is used as a heat source for heating the absorption liquid in the regeneration tower.