Condensate preheater for waste heat steam generator

Abstract

A condensate preheater for a waste-heat steam generator, including condensate preheater heating surfaces, around which exhaust gas of a gas turbine flows in operation in order to heat up water flowing in the condensate preheater heating surfaces, wherein a respective heat transfer coefficient of the condensate preheater heating surfaces is selected such that a surface temperature of the condensate preheater heating surfaces is above an exhaust gas dew point in operation, wherein the condensate preheater has a condensate preheater inlet and a condensate preheater outlet and the heat transfer coefficient at the condensate preheater inlet is reduced relative to the heat transfer coefficient at the condensate preheater outlet, is provided.

1 . A condensate preheater for a waste heat steam generator, comprising:
 a plurality of condensate preheater heating surfaces around which an exhaust gas from a gas turbine flows during operation to heat a water flowing into the plurality of condensate preheater heating surfaces;   wherein a respective heat transfer coefficient of the plurality of condensate preheater heating surfaces is selected such that in operation, a surface temperature of the plurality of condensate preheater heating surfaces lies above an exhaust gas dew point;   wherein the condensate preheater has a condensate preheater inlet and a condensate preheater outlet, and the respective heat transfer coefficient at the condensate preheater inlet is reduced compared with the respective heat transfer coefficient at the condensate preheater outlet.   
     
     
         2 . The condensate preheater as claimed in  claim 1 , wherein the exhaust gas dew point is a water vapor dew point. 
     
     
         3 . The condensate preheater as claimed in  claim 1 , wherein the exhaust gas dew point is a sulfuric acid dew point. 
     
     
         4 . The condensate preheater as claimed in  claim 1 , wherein a heat-insulating layer is applied to at least one condensate-carrying part of the plurality of condensate preheater heating surfaces lying closest to the condensate preheater inlet. 
     
     
         5 . The condensate preheater as claimed in  claim 1 , wherein at least one of the plurality of condensate preheater heating surfaces lying closest to the condensate preheater inlet is a pipe-in-pipe construction in which a heat-insulating layer is arranged in an inter-pipe space. 
     
     
         6 . The condensate preheater as claimed in  claim 5 , wherein the heat-insulating layer comprises sand.