Steam cooled type combined cycle power generation plant and operation method thereof

Abstract

A combined cycle power generation plant comprises a waste heat recovery boiler ( 20 ) having a stabilizing burner ( 25 ) at an upstream position thereof. The stabilizing burner is ignited during the time of start-up and speed increase of a gas turbine ( 11 ) so that steam generation at the waste heat recovery boiler is accelerated. The steam is used effectively for cooling the gas turbine, driving a steam turbine, and for gland steam. In addition, exhaust steam from the steam turbine is also used to cool the gas turbine. Consequently, the time for the plant to reach a full load can be shortened.

We claim:  
     
         1 . A power generation plant comprising: 
 a gas turbine unit including a gas turbine having a high temperature portion with a cooling component;    a steam turbine unit; and    a waste heat recovery unit including a waste heat recovery boiler having a stabilizing burner at an upstream position in said waste heat recovery boiler, said stabilizing burner being operable to create steam during at least one of a start-up period of operation and a speed-increasing period of operation of the power generation plant, said waste heat recovery boiler being operable to generate steam using waste heat from said gas turbine unit, wherein the steam generated by said waste heat recovery boiler drives said steam turbine unit, and wherein at least one of a portion of an exhaust steam from said steam turbine unit and a portion of the steam generated by said waste heat recovery boiler flows through said cooling component of said high temperature portion of said gas turbine so as to cool said high temperature portion.    
     
     
         2 . The plant of    claim 1   , further comprising a fuel supply source, said stabilizing burner having a fuel supply line, and said gas turbine unit including a combustor having a fuel supply line, wherein said fuel supply line of said stabilizing burner and said fuel supply line of said combustor are connected to said fuel supply source such that said fuel supply source supplies fuel to said stabilizing burner and said combustor.  
     
     
         3 . The plant of    claim 1   , wherein said steam turbine unit includes a high pressure steam turbine, an intermediate pressure turbine, and a low pressure turbine, wherein said high pressure steam turbine is connected to said cooling component of said high temperature portion of said gas turbine such that exhaust steam from said high pressure steam turbine is capable of flowing through said cooling component of said high temperature portion of said gas turbine.  
     
     
         4 . The plant of    claim 3   , wherein said waste heat recovery boiler includes a high pressure drum, an intermediate pressure drum, and a low pressure drum, wherein said intermediate pressure drum is connected to said cooling component of said high temperature portion of said gas turbine such that intermediate pressure steam from said intermediate pressure drum is capable of flowing through said cooling component of said high temperature portion of said gas turbine.  
     
     
         5 . The plant of    claim 1   , wherein said waste heat recovery boiler includes a high pressure drum, an intermediate pressure drum, and a low pressure drum, wherein said intermediate pressure drum is connected to said cooling component of said high temperature portion of said gas turbine such that intermediate pressure steam from said intermediate pressure drum is capable of flowing through said cooling component of said high temperature portion of said gas turbine.  
     
     
         6 . The plant of    claim 1   , wherein said gas turbine unit further includes an air compressor and a starting apparatus.  
     
     
         7 . The plant of    claim 6   , wherein said gas turbine, said air compressor, and said starting apparatus share a common shaft.  
     
     
         8 . The plant of    claim 1   , wherein said gas turbine unit further includes a starting apparatus connected to said stabilizing burner of said waste heat recovery unit such that said starting apparatus is operable to ignite said stabilizing burner when said starting apparatus is rotated to start said gas turbine unit.