Steam generator having an integrated modular heat exchanger

Abstract

A modular heat exchanger assembly for a steam generator includes a first fluid inlet conduit configured and disposed to be connected to a source of a first fluid, and a tube sheet coupled to the first fluid inlet conduit. The tube sheet includes a first surface and an opposing, second surface. A plurality of platen tubes extends from the second surface of the tube sheet. The plurality of platen tubes is configured and disposed to carry a second fluid in a heat exchange relationship with the first fluid in a heat exchange vessel. The modular heat exchanger assembly is configured and disposed to be selectively and readily removable from the heat exchange vessel.

What is claimed is: 
     
         1 . A modular heat exchanger assembly for a steam generator comprising:
 a first fluid inlet conduit configured and disposed to be connected to a source of a first fluid;   a tube sheet coupled to the first fluid inlet conduit, the tube sheet including a first surface and an opposing, second surface; and   a plurality of platen tubes extending from the second surface of the tube sheet, the plurality of platen tubes being configured and disposed to carry a second fluid in a heat exchange relationship with the first fluid in a heat exchange vessel, the modular heat exchanger assembly being configured and disposed to be selectively and readily removable from the heat exchange vessel.   
     
     
         2 . The modular heat exchanger assembly according to  claim 1 , wherein each of the plurality of platen tubes includes a first end portion, a second end portion and an intermediate portion defining a conduit extending therebetween, the first end portion being exposed at the first surface of the tube sheet. 
     
     
         3 . The modular heat exchanger assembly according to  claim 2 , further comprising: a platen header provided at the second end portion of the plurality of platen tubes, the platen header fluidically connecting each of the plurality of platen tubes at the second end portion. 
     
     
         4 . The modular heat exchanger assembly according to  claim 3 , further comprising: a second fluid inlet conduit fluidically connected to the platen header. 
     
     
         5 . The modular heat exchanger assembly according to  claim 2 , further comprising: a dome member arranged at the first surface of the tube sheet, the dome member fluidically connecting the first end portion of each of the plurality of platen tubes. 
     
     
         6 . The modular heat exchanger assembly according to  claim 5 , further comprising: an outlet fluidically connected to the dome member. 
     
     
         7 . The modular heat exchanger assembly according to  claim 2 , wherein the second end portion of select ones of the plurality of platen tubes is fluidically connected to the second end portion of select ones of others of the plurality of platen tubes. 
     
     
         8 . The modular heat exchanger assembly according to  claim 1 , further comprising: a plurality of outer tubes defining a membrane cage surrounding the plurality of platen tubes. 
     
     
         9 . The modular heat exchanger assembly according to  claim 8 , further comprising: an inlet conduit fluidically connected to the plurality of outer tubes defining the membrane cage. 
     
     
         10 . The modular heat exchanger assembly according to  claim 1 , wherein the plurality of platen tubes is arranged in one of a substantially linear configuration, an L-shaped configuration, and a triangular pitch configuration. 
     
     
         11 . A heat exchanger system comprising:
 a gasifier;   a heat exchange vessel coupled to the gasifier, the heat exchange vessel including an outer surface and an inner surface defining a heat exchange zone, the heat exchange vessel including an exposed end portion exposing the heat exchange zone;   a support ring arranged on the inner surface adjacent the exposed end portion; and   a modular heat exchanger assembly selectively removably arranged in the heat exchange zone, the modular heat exchanger assembly comprising:
 a first fluid inlet conduit configured and disposed to be connected to a source of a first fluid, the first fluid inlet conduit being fluidically connected to the heat exchange zone; 
 a tube sheet supported by the support ring and coupled to the first fluid inlet conduit, the tube sheet including a first surface and an opposing, second surface; and 
 a plurality of platen tubes extending from the second surface of the tube sheet into the heat exchange zone, the plurality of platen tubes being configured and disposed to carry a second fluid in a heat exchange relationship with the first fluid in the heat exchange vessel. 
   
     
     
         12 . The heat exchanger system according to  claim 11 , wherein each of the plurality of platen tubes includes a first end portion, a second end portion and an intermediate portion defining a conduit extending therebetween, the first end portion being exposed at the first surface of the tube sheet. 
     
     
         13 . The heat exchanger system according to  claim 12 , further comprising: a platen header provided at the second end portion of the plurality of platen tubes, the platen header fluidically connecting each of the plurality of platen tubes at the second end portion. 
     
     
         14 . The heat exchanger system according to  claim 13 , further comprising: a second fluid inlet conduit extending through the outer surface and fluidically connected to the platen header. 
     
     
         15 . The heat exchanger system according to  claim 12 , further comprising: a dome member arranged at the first surface of the tube sheet, the dome member fluidically connecting the first end portion of each of the plurality of platen tubes. 
     
     
         16 . The heat exchanger system according to  claim 15 , further comprising: an outlet zone fluidically connected to the dome member. 
     
     
         17 . The heat exchanger system according to  claim 11 , further comprising: an end cover coupled to the exposed end portion of the heat exchange vessel, the first fluid inlet conduit extending through the end cover. 
     
     
         18 . The heat exchanger system according to  claim 17 , further comprising: a refractory cage extending through the end cover along the first fluid inlet conduit, the refractory cage thermally isolating the first fluid inlet conduit from the second fluid in the heat exchange zone. 
     
     
         19 . The heat exchanger system according to  claim 11 , further comprising:
 a plurality of outer tubes defining a membrane cage surrounding the plurality of platen tubes; and   an inlet conduit fluidically connected to the plurality of outer tubes defining the membrane cage.   
     
     
         20 . The heat exchanger system according to  claim 11 , wherein the plurality of platen tubes is arranged in one of a substantially linear configuration, an L-shaped configuration, and a triangular pitch configuration.