Method for operating a steam turbine installation and a steam turbine installation that functions according thereto

Abstract

During the operation of a steam turbine installation ( 1 ), flue gas (RG) produced by combusting a fossil fuel (B) is firstly guided in a high-temperature heat exchanger ( 3 ) while exchanging heat with water vapor (WD) which flows in the water-steam circuit ( 6 ) of a steam turbine ( 7 ) and which is fed to the steam turbine ( 7 ) as fresh steam (FD) having a fresh steam temperature (T FD ) of preferably greater than 800 ° C. The flue gas (RG) that is cooled down in the high-temperature heat exchanger ( 3 ) is subsequently guided in a waste heat stem generator ( 4 ) while exchanging heat with feed water (SW), which flows in the water-steam circuit, whereupon inducing the production of water vapor (WD).

1 . A method of operating a steam turbine installation, in which method combustion gas (RG) generated by combustion of a fossil fuel (B) is guided so as to exchange heat with a medium (SW, WD) flowing in the water/steam cycle ( 6 ) of a steam turbine ( 7 ), in which the hot combustion gas (RG) is first supplied to the primary side of a high-temperature heat exchanger ( 3 ) and is there guided so as to exchange heat with steam (WD), which is supplied to the secondary side of the high-temperature heat exchanger ( 3 ) and flows in the water/steam cycle ( 6 ), the steam heated by this means being supplied to the steam turbine ( 7 ) as live steam (FD), and in which the combustion gas (RG) cooled in the high-temperature heat exchanger ( 3 ) is subsequently guided in a waste-heat steam generator ( 4 ) so as to exchange heat with feed water (SW) flowing in the water/steam cycle ( 6 ), the steam (WD) being generated by this means.  
     
     
         2 . The method as claimed in  claim 1 , in which the steam (WD) is heated in the high-temperature heat exchanger ( 3 ) to a live steam temperature (T FD ) greater than or equal to 800° C.  
     
     
         3 . The method as claimed in  claim 1  or  2 , in which the steam turbine ( 7 ) is cooled by the steam (WD) extracted from the water/steam cycle ( 6 ).  
     
     
         4 . The method according to one of  claims 1  to  3 , in which the steam (WD) generated in the waste-heat steam generator ( 4 ) is supplied to a separate steam turbine ( 15 ) and the steam (WD) expanded there—with work output—is supplied to the high-temperature heat exchanger ( 3 ).  
     
     
         5 . A steam turbine installation having a combustion installation ( 1 ) for a fossil fuel (B) for the generation of combustion gas (RG), which is guided in a high-temperature heat exchanger ( 3 ) and in a waste-heat steam generator ( 4 ) connected downstream on the combustion gas side of the high-temperature heat exchanger ( 3 ) so as to exchange heat with a medium (SW, WD) flowing in the water/steam cycle ( 6 ) of a steam turbine ( 7 ), and in which the steam side of the high-temperature heat exchanger ( 3 ) is connected between the waste-heat steam generator ( 4 ) and the steam turbine ( 7 ).  
     
     
         6 . The steam turbine installation as claimed in  claim 5 , characterized in that the steam turbine ( 7 ) is connected to a cooling steam line ( 13 ) by means of which the steam (WD) extracted from the water/steam cycle ( 6 ) can be supplied to the steam turbine ( 7 ) as cooling steam (KD).  
     
     
         7 . The steam turbine installation as claimed in  claim 6 , characterized in that the cooling steam line ( 13 ) is connected to a steam line ( 9 ) connecting the high-temperature heat exchanger ( 3 ) to the waste-heat steam generator ( 4 ).  
     
     
         8 . The steam turbine installation as claimed in one of  claims 5  to  7 , characterized by a separate steam turbine ( 15 ) connected on the steam side between the waste-heat steam generator ( 4 ) and the high-temperature heat exchanger ( 3 ).  
     
     
         9 . The steam turbine installation as claimed in  claim 8 , characterized by a steam line ( 17 ) connecting the separate steam turbine ( 15 ) with heating surfaces ( 8 ) of the high-temperature heat exchanger ( 3 ), to which steam line ( 17 ) is connected a cooling steam line ( 18 ) for supplying cooling steam (KD) to the steam turbine ( 7 ) connected downstream of the high-temperature heat exchanger ( 3 ) on the steam side.  
     
     
         10 . The steam turbine installation as claimed in one of  claims 5  to  9 , characterized in that an ash separator ( 2 ) is connected downstream of the combustion installation ( 1 ).