Circulating fluidized bed boiler

Abstract

A circulating fluidized bed boiler has reduced corrosion in the exchanging tube in an external heat exchanger. The circulating fluidized bed boiler has a furnace which combusts a fuel which is fluidized together with a bed material, a cyclone dust collector into which an flue gas which is generated by the combustion in the furnace is introduced and which catches particles in the flue gas, a separation loop, in a seal box, which separates corrosive components from the particles so as not to introduce the corrosive components to the external heat exchanger which is arranged downstream of the seal box.

What is claimed is:  
     
         1 . A circulating fluidized bed boiler comprising: 
 a furnace which combusts a fuel which is fluidized together with a bed material,    a cyclone dust collector into which an flue gas which is generated by a combustion in the furnace is introduced and which catches    a seal box into which the particles which are caught by the cyclone dust collector are introduced, and    an external heat exchanger which is arranged in a downstream of the seal box, wherein 
 said circulating fluidized bed boiler further provides a separation loop which separates corrosive components from said particles so as not to introduce the corrosive components to said external heat exchanger in said seal box.  
   
     
     
         2 . A circulating fluidized bed boiler according to  claim 1 , wherein said separation loop comprising a path through which said corrosive components which are originated by the combustion of said particles and air which is introduced to said separation loop.  
     
     
         3 . A circulating fluidized bed boiler according to  claim 2 , wherein said path is connected to said furnace.  
     
     
         4 . A circulating fluidized bed boiler according to  claim 1 , wherein said separation loop is arranged in a bottom part of said cyclone dust collector.  
     
     
         5 . A circulating fluidized bed boiler according to  claim 2 , wherein said separation loop is arranged in a bottom part of said cyclone dust collector.  
     
     
         6 . A circulating fluidized bed boiler according to  claim 3 , wherein said separation loop is arranged in a bottom part of said cyclone dust collector.  
     
     
         7 . A circulating fluidized bed boiler according to  claim 1 , wherein said seal box is separated into a plurality of compartments and said separation loop is arranged in one of said compartments which is arranged upstream of the other of said compartments.  
     
     
         8 . A circulating fluidized bed boiler according to  claim 2 , wherein said seal box is separated into a plurality of compartments and said separation loop is arranged in one of said compartments which is arranged upstream of the other of said compartments along a stream.  
     
     
         9 . A circulating fluidized bed boiler according to  claim 3 , wherein said seal box is separated to a plurality of compartments and said separation loop is arranged in one of said compartments which is arranged upstream of the other of said compartments.  
     
     
         10 . A circulating fluidized bed boiler according to  claim 4 , wherein said seal box is separated to a plurality of compartments and said separation loop is arranged in one of said compartments which is arranged upstream of the other of said compartments.  
     
     
         11 . A circulating fluidized bed boiler according to  claim 5 , wherein said seal box is separated to a plurality of compartments and said separation loop is arranged one of said compartments which is arranged upstream of the other of said compartments.  
     
     
         12 . A circulating fluidized bed boiler according to  claim 8 , wherein said path connects the other component which is arranged downstream of said one component with said furnace.  
     
     
         13 . A circulating fluidized bed boiler according to  claim 9 , wherein said path connects the other component which is arranged downstream of said one component with said furnace.  
     
     
         14 . A circulating fluidized bed boiler according to  claim 11 , wherein said path connects the other component which is arranged downstream of said one component with said furnace.