Hybrid Cooling System

Abstract

The invention is a hybrid cooling system for condensing the exhaust steam of a steam turbine ( 10 ), which cooling system comprises a dry cooling circuit ( 11 ), a dry air-cooled unit ( 12 ) performing heat dissipation of cooling water flowing therein, and a wet cooling circuit ( 14 ) and a wet cooled unit ( 15 ) performing heat dissipation of the cooling water flowing therein. According to the invention, the cooling water flowing in the dry cooling circuit ( 11 ) is separated from the cooling water flowing in the wet cooling circuit ( 14 ), and the dry and wet cooling circuits ( 11, 14 ) are connected to a common condenser.

1 . A hybrid cooling system for condensing exhaust steam of a steam turbine ( 10 ), the cooling system comprising
 a dry cooling circuit and a dry air-cooled unit for effecting heat dissipation of the cooling water flowing in the dry cooling circuit,   a wet cooling circuit and a wet cooled unit for effecting heat dissipation of the cooling water flowing in the wet cooling circuit,   wherein   the cooling water flowing in the dry cooling circuit is separated from the cooling water flowing in the wet cooling circuit, and the dry and wet cooling circuits are connected to a common condenser,   characterised by   comprising a water-water heat exchanger suitable for heat transfer between the cooling water flowing in the dry cooling circuit and the cooling water flowing in the wet cooling circuit.   
     
     
         2 . The cooling system according to  claim 1 , characterised in that the condenser is a surface condenser comprising a surface condenser part for each of the two cooling circuits. 
     
     
         3 . The cooling system according to  claim 2 , characterised by comprising—for the case if the wet cooling circuit is shut off—valves suitable for switching the condenser part of the wet cooling circuit to the dry cooling circuit. 
     
     
         4 . The cooling system according to  claim 1 , characterised in that the condenser is a hybrid condenser, which comprises a direct contact condenser part associated with the dry cooling circuit and a surface condenser part associated with the wet cooling circuit. 
     
     
         5 . The cooling system according to  claim 4 , characterised in that in the hybrid condenser, the direct contact condenser part and the surface condenser part are arranged one after the other in the direction of steam flowing. 
     
     
         6 . The cooling system according to  claim 1 , characterised in that the dry air-cooled unit is a natural or fan draught dry cooling tower, and the wet cooled unit is a natural or fan draught wet cooling tower. 
     
     
         7 . The cooling system according to  claim 1 , characterised in that the dry air-cooled unit is configured as a dry cooling part of a hybrid cooling tower and the wet cooled unit as a wet part of the hybrid cooling tower. 
     
     
         8 . (canceled) 
     
     
         9 . The cooling system according to  claim 1 , characterised in that through the water-water heat exchanger, the two cooling circuits are connected in counterflow in series in a way that it is suitable for the further cooling in series of at least a part flow of the cooled cooling water in the dry air-cooled unit with at least a part flow of the cooling water cooled in the wet cooled unit. 
     
     
         10 . The cooling system according to  claim 7 , characterised in that through the water-water heat exchanger, the two cooling circuits are coupled in counterflow in parallel in a way that it is suitable for cooling a part of the warmed up cooling water coming from the condenser part associated with the dry cooling circuit in the water-water heat exchangers, instead of the dry air-cooled unit, by using at least a part of the cooling water flowing in the wet cooling circuit. 
     
     
         11 . The cooling system according to  claim 10 , characterised in that it comprises a serially and also an in parallel connected water-water heat exchanger. 
     
     
         12 . The cooling system according to  claim 11 , characterised in that from the aspect of the dry cooling circuit, the cooling of the serially connected water-water heat exchanger and the in parallel connected water-water heat exchanger is effected serially from the aspect of the cooling water flow of the wet circuit. 
     
     
         13 . The cooling system according to  claim 9 , characterised in that it comprises valves suitable for a selective connection or disconnection of the water-water heat exchangers. 
     
     
         14 . A hybrid cooling system for condensing exhaust steam of a steam turbine the coolings system comprising
 a dry cooling circuit and a dry air-cooled unit for effecting heat dissipation of the cooling water flowing in the dry cooling circuit,   a wet cooling circuit and a wet cooled unit for effecting heat dissipation of the cooling water flowing in the wet cooling circuit,   the cooling water flowing in the dry cooling circuit is separated from the cooling water flowing in the wet cooling circuit, and the dry and wet cooling circuits are connected to a common condenser,   wherein the condenser is a hybrid condenser, which comprises a direct contact condenser part associated with the dry cooling circuit and a surface condenser part associated with the wet cooling circuit,   characterised in that for the case if the condensate collected in the condenser has a higher temperature than a predetermined limit temperature, it comprises a condensate supply line to enable a feeding of a condensate polishing unit at least partly with the cooling water coming from the dry air-cooled unit.   
     
     
         15 . (canceled) 
     
     
         16 . The cooling system according to  claim 10 , characterised in that the wet cooling circuit is connected to the dry cooling circuit thermally via the water-water heat exchangers.