Boiler equipped with a superheater

Abstract

A boiler ( 1 ) comprising at least: a furnace ( 2 ), in whose lower part the combustion used as the primary source of thermal energy of the boiler is configured to take place; devices ( 6 ) for supplying fuel into the furnace; devices ( 3, 7, 8, 26 ) for supplying combustion air into the furnace; one or more flue gas ducts ( 11 ); at least one chamber ( 17 ) accommodating at least one steam superheater ( 15 ) for recovering thermal energy. Said chamber is configured to allow a direct line of sight ( 16 ) between said superheater and said primary source, to enable the reception of thermal energy by means of thermal radiation. Said chamber is further configured to prevent the entry of said flue gases ( 19 ) to said superheater either totally or almost totally, to avoid the reception of thermal energy by convection.

1 . A boiler for producing and recovering thermal energy, the boiler comprising at least:
 a furnace limited by walls, a bottom and a top, wherein the combustion used as the primary source of thermal energy of the boiler is arranged to take place in the lower part of the furnace;   devices for supplying fuel to the furnace for combustion;   devices for supplying combustion gas to the furnace for combustion;   one or more flue gas ducts placed in the upper part of the furnace and leading the flue gases developed in the combustion out of the furnace;   wherein the boiler also comprises:   at least one chamber accommodating at least one steam superheater to recover thermal energy;   wherein said chamber is configured to allow a direct line of sight between said superheater and said primary source, to enable the reception of thermal energy by means of thermal radiation; and   wherein said chamber is further configured to prevent the entry of said flue gases into said superheater either totally or almost totally, to avoid the reception of thermal energy by convection.   
     
     
         2 . The boiler according to  claim 1 , wherein the chamber is connected to the furnace via the entrance, through which entrance a direct line of sight is provided between the superheater and said primary source. 
     
     
         3 . The boiler according to  claim 2 , wherein the bottom of the chamber is open and constitutes said entrance. 
     
     
         4 . The boiler according to  claim 1 , wherein the gas present in the chamber is configured to remain in the chamber by the effect of dynamic pressure of the flow of the flue gases. 
     
     
         5 . The boiler according to  claim 1 , wherein the boiler further comprises a nose placed in the upper part of the furnace, to guide the flue gases, wherein said chamber is placed inside the nose. 
     
     
         6 . The boiler according to  claim 1 , wherein the chamber is placed outside the furnace and it is provided with a connection through the wall of the furnace, or the chamber is placed inside the furnace, wherein the bottom or a side of the chamber is open and constitutes said entrance. 
     
     
         7 . The boiler according to  claim 1 , wherein at least one nozzle is placed in the chamber or in the vicinity of the chamber, for blowing gas, powder or liquid into the furnace, directed in such a way that flue gases are guided away from the chamber and the entry of flue gases into the chamber is prevented. 
     
     
         8 . The boiler according to  claim 1 , wherein at least one nozzle is placed in the chamber or in the vicinity of the chamber, for blowing liquid, powder or gas into the chamber, wherein said liquid, powder or gas is configured to neutralize the effect of corrosive or aggressive substances in the flue gas, to dilute the concentration of flue gas in the chamber, or to replace the flue gas in the chamber with a non-corrosive or non-aggressive gas. 
     
     
         9 . The boiler according to  claim 7 , wherein the gas is air or an inert gas. 
     
     
         10 . The boiler according to  claim 7 , wherein said liquid, powder or gas is iron(III)sulphate Fe 2 (SO 4 ) 3  or aluminium(III)sulphate Al 2 (SO 4 ) 3 , or a mixture of them. 
     
     
         11 . The boiler according to  claim 1 , wherein the superheater comprises pipes connected to each other, inside which the medium flows, to which the thermal energy collected by the superheated is transferred. 
     
     
         12 . The boiler according to  claim 1 , wherein the boiler is a bubbling fluidized bed boiler or a circulating fluidized bed boiler, or a soda recovery boiler, or a boiler applying combustion on a grate. 
     
     
         13 . The boiler according to  claim 1 , wherein the boiler is a bubbling fluidized bed boiler or a circulating fluidized bed boiler, wherein the boiler also comprises a fluidized bed placed in the lower part of the furnace, and devices for supplying fluidizing air into the furnace. 
     
     
         14 . The boiler according to  claim 2 , wherein the gas present in the chamber is configured to remain in the chamber by the effect of dynamic pressure of the flow of the flue gases. 
     
     
         15 . The boiler according to  claim 3 , wherein the gas present in the chamber is configured to remain in the chamber by the effect of dynamic pressure of the flow of the flue gases. 
     
     
         16 . The boiler according to  claim 2 , wherein the boiler further comprises a nose placed in the upper part of the furnace, to guide the flue gases, wherein said chamber is placed inside the nose. 
     
     
         17 . The boiler according to  claim 3 , wherein the boiler further comprises a nose placed in the upper part of the furnace, to guide the flue gases, wherein said chamber is placed inside the nose. 
     
     
         18 . The boiler according to  claim 4 , wherein the boiler further comprises a nose placed in the upper part of the furnace, to guide the flue gases, wherein said chamber is placed inside the nose. 
     
     
         19 . The boiler according to  claim 2 , wherein the chamber is placed outside the furnace and it is provided with a connection through the wall of the furnace, or the chamber is placed inside the furnace, wherein the bottom or a side of the chamber is open and constitutes said entrance. 
     
     
         20 . The boiler according to  claim 3 , wherein the chamber is placed outside the furnace and it is provided with a connection through the wall of the furnace, or the chamber is placed inside the furnace, wherein the bottom or a side of the chamber is open and constitutes said entrance.