Post-combustion processing in power plants

Abstract

A system and method for configuring a steam turbine in a power plant to supply steam from a low pressure section of the steam turbine to a flue-gas processing unit in the power plant.

1 . A power plant comprising:
 a boiler configured to combust fuel, vaporize liquid water into steam, and discharge a combustion exhaust;   a treatment unit configured to process the combustion exhaust discharged from the boiler;   a steam turbine configured to receive steam from the boiler, wherein the steam turbine comprises a shaft, an intermediate pressure section, and a low pressure section, and wherein the steam turbine is configured to provide steam from the low pressure section to the treatment unit; and   a load coupled to the shaft of the steam turbine and configured to be driven by the steam turbine.   
     
     
         2 . The power plant of  claim 1 , wherein the treatment unit comprises a carbon dioxide separation unit. 
     
     
         3 . The power plant of  claim 2 , wherein the carbon dioxide separation unit comprises a stripper and a reboiler associated with the stripper, wherein the reboiler is configured to receive steam from the low pressure section. 
     
     
         4 . The power plant of  claim 2 , comprising a conduit coupling the low pressure section with a reboiler in the carbon dioxide separation unit. 
     
     
         5 . The power plant of  claim 1 , wherein the steam turbine comprises a high pressure section. 
     
     
         6 . A method of operating a power plant, comprising:
 feeding fuel to a boiler;   combusting the fuel in the boiler;   discharging a combustion exhaust from the boiler;   processing the combustion exhaust in a treatment unit;   feeding liquid water to the boiler;   vaporizing the liquid water into steam via heat generated by combusting the fuel;   supplying steam from the boiler to a steam turbine; and   supplying steam from a low pressure section of the steam turbine to the treatment unit.   
     
     
         7 . The method of  claim 6 , wherein processing comprises recovering carbon dioxide from the combustion exhaust in the treatment unit. 
     
     
         8 . The method of  claim 7 , wherein supplying steam to the treatment unit comprises supplying steam from the low pressure section to a stripper reboiler in the treatment unit. 
     
     
         9 . The method of  claim 6 , wherein feeding and combusting fuel comprises feeding coal to the boiler and combusting the coal in the boiler. 
     
     
         10 . The method of  claim 6 , comprising producing electricity via a generator coupled to a shaft of the steam turbine. 
     
     
         11 . A method comprising configuring a steam turbine in a power plant to supply steam from a low pressure section of the steam turbine to a flue-gas processing unit, wherein configuring the steam turbine comprises installing a steam turbine at the power plant or retrofitting an existing steam turbine disposed at the power plant. 
     
     
         12 . The method of  claim 11 , wherein retrofitting comprises replacing or modifying a low pressure section of the steam turbine. 
     
     
         13 . The method of  claim 11 , wherein a low pressure section of the configured steam turbine comprises one or more steam extractions sized collectively to extract 10% to 25%, by weight, of an amount of steam entering the low pressure section. 
     
     
         14 . The method of  claim 11 , wherein configuring the steam turbine comprises reducing stage size subsequent to the steam extraction correlative with an amount of steam to be extracted via the steam extraction. 
     
     
         15 . The method of  claim 11 , wherein the flue-gas processing unit comprises a carbon dioxide separation unit. 
     
     
         16 . The method of  claim 15 , comprising configuring a stripper reboiler in the carbon dioxide separation unit to receive steam from the low pressure section. 
     
     
         17 . A steam turbine comprising:
 a shaft;   a high pressure section;   an intermediate pressure section;   a low pressure section configured with a steam extraction to provide steam to a flue-gas processing unit.   
     
     
         18 . The steam turbine of  claim 17 , wherein the flue-gas processing unit comprises a carbon dioxide separation unit, and the steam extraction comprises a plurality of steam extractions sized collectively to provide at least an amount of steam required for operation of a stripper reboiler in the carbon dioxide separation unit. 
     
     
         19 . The steam turbine of  claim 17 , wherein at least one stage in the low pressure section downstream of the steam extraction is reduced in size correlative to an amount of steam extracted via the steam extraction. 
     
     
         20 . The steam turbine of  claim 17 , wherein the steam extraction comprises a plurality of steam extractions sized collectively to extract 10% to 25%, by weight, of an amount of steam entering the low pressure section.