Waste heat steam generator and method for improved operation of a waste heat steam generator

Abstract

A heat recovery steam generator is provided. The heat recovery steam generator includes an exhaust gas inlet for receiving an exhaust gas from a gas turbine. A first superheater is positioned in a flow direction of the exhaust gas. A heating surface is disposed between the exhaust gas inlet and the first superheater. A separator is connected downstream of the heating surface on a secondary side of the heating surface.

1 .- 18 . (canceled) 
     
     
         19 . A heat recovery steam generator, comprising:
 an exhaust gas inlet for receiving an exhaust gas from a gas turbine;   a first superheater positioned in a flow direction of the exhaust gas;   a heating surface disposed between the exhaust gas inlet and the first superheater; and   a separator connected downstream of the heating surface on a secondary side of the heating surface.   
     
     
         20 . The heat recovery steam generator as claimed in  claim 19 , wherein the heating surface is connected on the secondary side at an outlet side to a steam line leading to a high-pressure stage of a steam turbine. 
     
     
         21 . The heat recovery steam generator as claimed in  claim 19 , wherein the separator is an inertial separator. 
     
     
         22 . The heat recovery steam generator as claimed in  claim 19 , wherein water is fed to the secondary side of the heating surface. 
     
     
         23 . The heat recovery steam generator as claimed in  claim 19 , wherein water from an economizer is fed to the secondary side of the heating surface. 
     
     
         24 . The heat recovery steam generator as claimed in  claim 23 , wherein the economizer is a high-pressure economizer. 
     
     
         25 . The heat recovery steam generator as claimed in  claim 19 , wherein the heating surface is a once-through evaporator heating surface. 
     
     
         26 . The heat recovery steam generator as claimed in  claim 19 , wherein the heating surface is connected on the secondary side at an inlet side to a high-pressure pre-superheater. 
     
     
         27 . The heat recovery steam generator as claimed in  claim 19 , wherein the heating surface is connected on the secondary side at an inlet side to an intermediate superheater. 
     
     
         28 . The heat recovery steam generator as claimed in  claim 19 , wherein the first superheater is a high-pressure superheater. 
     
     
         29 . The heat recovery steam generator as claimed in  claim 26 , further comprising a high-pressure steam bypass for bypassing the high-pressure superheater. 
     
     
         30 . The heat recovery steam generator as claimed in  claim 28 , further comprising a high-pressure steam bypass for bypassing the high-pressure superheater. 
     
     
         31 . The heat recovery steam generator as claimed in  claim 27 , further comprising an intermediate superheater steam bypass for bypassing an intermediate superheater. 
     
     
         32 . The heat recovery steam generator as claimed in  claim 19 , further comprising an inlet header for the heating surface, wherein the inlet header is a tube-in-tube inlet header. 
     
     
         33 . A combined-cycle gas and steam turbine plant; comprising
 a gas turbine; a steam turbine; and   a heat recovery steam generator, comprising:
 an exhaust gas inlet for receiving an exhaust gas from the gas turbine; 
 a first superheater positioned in a flow direction of the exhaust gas; 
 a heating surface disposed between the exhaust gas inlet and the first superheater; and 
 a separator connected downstream of the heating surface on a secondary side of the heating surface. 
   
     
     
         34 . A method for operating a heat recovery steam generator, comprising:
 positioning a first superheater in the flow direction of the exhaust gas;   cooling a hot exhaust gas is before it reaches the first superheater; and   separating water that has not evaporated during cooling of the exhaust gas in a cyclone separator with separating flask.   
     
     
         35 . The method as claimed in  claim 34 , wherein the exhaust gas is cooled by hot high-pressure feedwater. 
     
     
         36 . The method as claimed in  claim 34 , wherein the exhaust gas is cooled by pre-superheater steam. 
     
     
         37 . The method as claimed in  claim 34 , further comprising mixing steam produced during cooling of the exhaust gas with high-pressure steam.