Combined cycle plant injection water preheating arrangement

Abstract

A combined cycle plant ( 10 ), including a heat recovery steam generator (HRSG) ( 36 ), a working fluid which is heated by the HRSG and effective to operate a steam turbine ( 38 ), and a blowdown heat transfer arrangement ( 90, 92, 94,102, 104 ) configured to capture heat present in blowdown water drawn from the working fluid and to transfer the heat to injection water ( 28 ), a gas turbine engine ( 16 ) having a compressor ( 18 ), a combustor ( 20 ), and a turbine ( 22 ), and a water injection arrangement ( 30 ) configured to inject the injection water into the combustor

The invention claimed is: 
     
         1 . A combined cycle plant, comprising
 a heat recovery steam generator (HRSG), a working fluid which is heated by the HRSG and effective to operate a steam turbine, and a blowdown heat transfer arrangement configured to capture heat present in blowdown water drawn from the working fluid and to transfer the heat to injection water;   a gas turbine engine comprising a compressor, combustor, and a turbine exhausting to the HRSG, and   a water injection arrangement configured to inject the injection water into the combustor.   
     
     
         2 . The combined cycle plant of  claim 1 , further comprising a steam drum, and a blowdown arrangement configured to remove blowdown from the steam drum, wherein the blowdown heat transfer arrangement is configured to extract heat from the blowdown from the steam drum. 
     
     
         3 . The combined cycle plant of  claim 2 , wherein the steam drum comprises a first pressure steam drum, wherein the combined cycle plant further comprises
 a second pressure steam drum, and   a second blowdown arrangement configured to remove blowdown from the second pressure steam drum, and   wherein the blowdown heat transfer arrangement is configured to transfer heat from blowdown from the first pressure steam drum to the injection water and then to transfer heat from blowdown from the second pressure steam drum to injection water heated by the heat from the first pressure steam drum   
     
     
         4 . The combined cycle plant of  claim 3 , wherein the first pressure steam drum is an intermediate pressure steam drum and the second pressure steam drum is a high pressure steam drum 
     
     
         5 . The combined cycle plant of  claim 1 , further comprising a kettle boiler, wherein the blowdown heat transfer arrangement is configured to extract heat from blowdown from the kettle boiler 
     
     
         6 . The combined cycle plant of  claim 1 , wherein the blowdown heat transfer arrangement is further configured to transfer heat to a fuel oil used in the combustor. 
     
     
         7 . The combined cycle plant of  claim 1 , wherein the blowdown heat transfer arrangement is further configured to transfer heat to exhaust from the gas turbine engine that is flowing though the HRSG. 
     
     
         8 . A combined cycle plant, comprising a Brayton cycle arrangement comprising a compressor, a combustor configured to generate a combustion process, and a turbine,
 a diluent injection arrangement configured to inject a diluent into the combustion process, and   a Rankine cycle arrangement configured to receive exhaust from the combustion process, and   a blowdown heat transfer arrangement configured to capture heat produced from a blowdown flow of the Rankine cycle arrangement and to transfer the heat to the diluent.   
     
     
         9 . The combined cycle plant of  claim 8 , wherein the Rankine cycle arrangement comprises a heat recovery steam generator and an associated steam drum, and wherein the blowdown flow is from the associated steam drum 
     
     
         10 . The combined cycle plant of  claim 8 , wherein the Rankine cycle arrangement comprises a heat recovery steam generator and a steam drum,
 wherein the blowdown flow comprises a blowdown flow from the steam drum, and   wherein the blowdown heat transfer arrangement is configured to transfer the heat to the diluent from the blowdown flow from the steam drum   
     
     
         11 . The combined cycle plant of  claim 8 , wherein the Rankine cycle arrangement comprises a heat recovery steam generator and an associated kettle boiler, and wherein the blowdown flow is from the associated kettle boiler 
     
     
         12 . The combined cycle plant of  claim 8 , wherein the blowdown heat transfer arrangement is also configured to transfer heat to a fuel oil used in the Brayton cycle arrangement. 
     
     
         13 . The combined cycle plant of  claim 8 , wherein the Rankine cycle arrangement comprises a heat recovery steam generator configured to receive the exhaust from the combustion process, and wherein heat is also transferred to the exhaust and is effective to prevent the exhaust from falling below a threshold temperature while within the heat recovery steam generator 
     
     
         14 . A combined cycle plant, comprising
 a Brayton cycle arrangement; and   a Rankine cycle arrangement comprising a blowdown arrangement and a blowdown heat transfer arrangement configured to capture heat from the blowdown arrangement and to transfer the heat to a non fuel fluid associated with the Brayton cycle arrangement   
     
     
         15 . The combined cycle plant of  claim 14 , wherein the heat is transferred to a diluent injected into a combustor of the Brayton cycle arrangement 
     
     
         16 . The combined cycle plant of  claim 14 , wherein the Rankine cycle arrangement comprises a heat recovery steam generator configured to receive exhaust from a gas turbine engine of the Brayton cycle arrangement, and wherein the heat is transferred to the exhaust and is effective to prevent the exhaust from falling below a threshold temperature while within the heat recovery steam generator 
     
     
         17 . The combined cycle plant of  claim 14 , wherein the Rankine cycle arrangement comprises a heat recovery steam generator and an associated steam drum, and wherein the blowdown arrangement is configured to blowdown the associated steam drum. 
     
     
         18 . The combined cycle plant of  claim 14 , wherein the Rankine cycle arrangement comprises a heat recovery steam generator and an associated kettle boiler, and wherein the blowdown arrangement is configured to blowdown the associated kettle boiler 
     
     
         19 . The combined cycle plant of  claim 14 , wherein the blowdown heat transfer arrangement is also configured to transfer heat to a fuel oil used in the Brayton cycle arrangement