Steam turbine, system, and method of operation

Abstract

Embodiments of the invention relate generally to steam turbines, steam turbine systems, and methods for their operation and, more particularly, to high-pressure-intermediate-pressure (HPIP) steam turbine configurations having pressure drop-limited seals and exhibiting reduced mid-packing and/or end-packing leakage. One embodiment of the invention provides a combined high-pressure-intermediate-pressure (HPIP) steam turbine comprising: a high-pressure section; an intermediate-pressure section sharing a common rotor with the high-pressure section; at least one packing ring disposed along a length of the rotor and between the high-pressure section and the intermediate-pressure section; and at least one conduit having a first end disposed adjacent a packing ring and a second end disposed adjacent a steampath stage of the high-pressure section.

1 . A combined high-pressure-intermediate-pressure (HPIP) steam turbine comprising:
 a high-pressure section;   an intermediate-pressure section sharing a common rotor with the high-pressure section;   at least one packing ring disposed along a length of the rotor and between the high-pressure section and the intermediate-pressure section; and   at least one conduit having a first end disposed adjacent a packing ring and a second end disposed adjacent a steampath stage of the high-pressure section.   
     
     
         2 . The combined HPIP steam turbine of  claim 1 , wherein the at least one packing ring includes a pressure drop-limited seal. 
     
     
         3 . The combined HPIP steam turbine of  claim 2 , wherein the pressure drop-limited seal includes an element adapted to move in response to a pressure difference across the pressure drop-limited seal. 
     
     
         4 . The combined HPIP steam turbine of  claim 2 , wherein the first end of the at least one conduit is adjacent the at least one packing ring. 
     
     
         5 . The combined HPIP steam turbine of  claim 2 , wherein the at least one conduit includes a plurality of conduits and a first end of each conduit is disposed adjacent a packing ring including a pressure drop-limited seal. 
     
     
         6 . The combined HPIP steam turbine of  claim 2 , wherein the pressure drop-limited seal is selected from a group consisting of: a brush seal and a leaf seal. 
     
     
         7 . The combined HPIP steam turbine of  claim 6 , wherein the pressure drop-limited seal is a brush seal. 
     
     
         8 . The combined HPIP steam turbine of  claim 2 , wherein the at least one conduit is capable of moving a quantity of steam between the steampath stage and an area adjacent the packing ring. 
     
     
         9 . The combined HPIP steam turbine of  claim 8 , wherein the quantity of steam is capable of reducing a pressure difference across the pressure drop-limited seal to less than a maximum design pressure difference for the seal. 
     
     
         10 . A separate high-pressure-intermediate-pressure (HPIP) steam turbine comprising:
 a high-pressure section;   an intermediate-pressure section;   a low-pressure section;   at least one rotor engaging at least one of the high-pressure section, the intermediate-pressure section, or the low-pressure section;   an end-packing region having at least one packing ring disposed along a length of the at least one rotor; and   at least one conduit having a first end disposed adjacent the end-packing region and a second end disposed adjacent a steampath stage of the high-pressure section.   
     
     
         11 . The separate HPIP steam turbine of  claim 10 , wherein the at least one packing ring includes a pressure drop-limited seal. 
     
     
         12 . The separate HPIP steam turbine of  claim 11 , wherein the pressure drop-limited seal includes an element adapted to move in response to a pressure difference across the pressure drop-limited seal. 
     
     
         13 . The separate HPIP steam turbine of  claim 11 , wherein the first end of the at least one conduit is adjacent the at least one packing ring. 
     
     
         14 . The separate HPIP steam turbine of  claim 11 , wherein the at least one conduit includes a plurality of conduits and a first end of each conduit is disposed adjacent a packing ring including a pressure drop-limited seal. 
     
     
         15 . The separate HPIP steam turbine of  claim 11 , wherein the pressure drop-limited seal is selected from a group consisting of: a brush seal and a leaf seal. 
     
     
         16 . The separate HPIP steam turbine of  claim 15 , wherein the pressure drop-limited seal is a brush seal. 
     
     
         17 . The separate HPIP steam turbine of  claim 11 , wherein the at least one conduit is capable of moving a quantity of steam between the steampath section and the area adjacent the end-packing region. 
     
     
         18 . The separate HPIP steam turbine of  claim 17 , wherein the quantity of steam is capable of reducing a pressure difference across the pressure drop-limited seal to less than a maximum design pressure difference for the seal. 
     
     
         19 . A steam turbine system comprising:
 a high-pressure-intermediate-pressure (HPIP) steam turbine comprising:
 a high-pressure section; 
 an intermediate-pressure section; 
 at least one rotor engaging at least one of the high-pressure section and the intermediate-pressure section; 
 at least one packing ring disposed along a length of the at least one rotor; and 
 at least one conduit having a first end disposed adjacent a packing ring and a second end disposed adjacent a steampath stage of the high-pressure section; and 
   a steam-generating apparatus for providing a quantity of steam to the steam turbine.   
     
     
         20 . The steam turbine system of  claim 19 , wherein the high-pressure section and the intermediate-pressure section share a common rotor. 
     
     
         21 . The steam turbine system of  claim 19 , wherein the at least one packing ring includes a pressure drop-limited seal. 
     
     
         22 . The steam turbine system of  claim 21 , wherein the pressure drop-limited seal includes an element adapted to move in response to a pressure difference across the pressure drop-limited seal. 
     
     
         23 . A method of operating a high-pressure-intermediate-pressure (HPIP) steam turbine, the method comprising:
 sealing against a rotor of the HPIP steam turbine using at least one packing ring having a pressure drop-limited seal; and   directing a quantity of steam between a steampath stage of a high-pressure section of the HPIP steam turbine and a mid-packing section of the HPIP steam turbine containing the at least one packing ring, such that a pressure difference across the pressure drop-limited seal is no greater than a maximum design pressure difference of the pressure drop-limited seal.   
     
     
         24 . The method of  claim 23 , wherein the pressure drop-limited seal is selected from a group consisting of: a brush seal and a leaf seal.