Boiler structure

Abstract

A boiler structure capable of efficiently alleviating or preventing corrosion and slagging on furnace walls in a furnace is provided. A circulating firing boiler structure is configured so that fuel and combustion air supplied into a furnace ( 11 ) from burners ( 12 ) disposed at a plurality of positions on furnace walls ( 11 a ) forming a rectangular cross section are combusted so as to form a swirling flow. Air-supplying parts ( 20 ) are disposed near flame-affected portions of furnace wall surfaces, where flames formed by the respective burners ( 12 ) approach or contact, to form regions having a higher air concentration than the peripheries thereof.

1 : A circulating firing boiler structure configured so that fuel and combustion air supplied into a furnace from burners disposed at a plurality of positions on furnace walls forming a rectangular cross section are combusted so as to form a swirling flow,
 wherein air-supplying parts are disposed near flame-affected portions of furnace wall surfaces, where flames formed by the respective burners approach or contact, to form regions having a higher air concentration than the peripheries thereof.   
     
     
         2 : The boiler structure according to  claim 1 , wherein the regions having a higher air concentration are formed so as to cover a reducing-combustion zone inside the furnace in a vertical direction. 
     
     
         3 : The boiler structure according to  claim 1 , wherein the air-supplying parts introduce low-pressure secondary burner air from the adjacent burners through bypass routes. 
     
     
         4 : The boiler structure according to  claim 1 , wherein the air-supplying parts are disposed around deslagger nozzles. 
     
     
         5 : The boiler structure according to  claim 2 , wherein the air-supplying parts introduce low-pressure secondary burner air from the adjacent burners through bypass routes. 
     
     
         6 : The boiler structure according to  claim 2 , wherein the air-supplying parts are disposed around deslagger nozzles. 
     
     
         7 : The boiler structure according to  claim 3 , wherein the air-supplying parts are disposed around deslagger nozzles.