Boiler and method for controlling boiler

Abstract

An object of the present disclosure is to appropriately reduce NOx and CO. A boiler includes: a can body having water pipe; a burner for supplying primary fuel and air into the can body; a secondary fuel supply unit for supplying secondary fuel into the can body downstream of the burner in a flow direction of combustion gas; a cooling line for introducing a cooling fluid for reducing temperature of a predetermined space in the can body downstream of the burner in the flow direction of the combustion gas; a flow rate adjusting unit capable of adjusting a flow rate of the cooling fluid introduced into the can body from the cooling line; and a control unit for controlling the flow rate adjusting unit to control the flow rate of the cooling fluid such that the temperature of the predetermined space is 800° C. or more and 1200° C. or less.

1 . A boiler comprising:
 a can body having water pipe;   a burner connected to the can body and for supplying primary fuel and air into the can body;   a secondary fuel supply unit for supplying secondary fuel into the can body downstream of the burner in a flow direction of combustion gas;   a cooling line for introducing a cooling fluid for reducing temperature of a predetermined space in the can body downstream of the burner in the flow direction of the combustion gas;   a flow rate adjusting unit provided in the cooling line and capable of adjusting a flow rate of the cooling fluid introduced into the can body from the cooling line; and   a control unit for controlling the flow rate adjusting unit to control the flow rate of the cooling fluid introduced into the can body such that the temperature of the predetermined space is 800° C. or more and 1200° C. or less.   
     
     
         2 . The boiler according to  claim 1 , wherein the control unit controls the flow rate adjusting unit such that a rate increases at which the flow rate of the cooling fluid increases when a supply amount of the primary fuel increases, as the supply amount of the primary fuel increases. 
     
     
         3 . The boiler according to  claim 1 , wherein the secondary fuel supply unit is connected to the cooling line, and supplies the secondary fuel into the can body in a state of being mixed with the cooling fluid. 
     
     
         4 . The boiler according to  claim 1 , wherein the secondary fuel supply unit supplies the secondary fuel into the can body downstream of the cooling line in the flow direction of the combustion gas. 
     
     
         5 . The boiler according to  claim 1 , wherein the cooling line introduces at least one or more of exhaust gas discharged from the can body, steam, water, and inert gas into the can body as the cooling fluid. 
     
     
         6 . The boiler according to  claim 3 , wherein
 the flow rate adjusting unit is a fan for supplying the exhaust gas discharged from the can body into the cooling line, and   the cooling line introduces the exhaust gas supplied from the flow rate adjusting unit into the can body as the cooling fluid.   
     
     
         7 . (canceled) 
     
     
         8 . The boiler according to  claim 2 , wherein the secondary fuel supply unit is connected to the cooling line, and supplies the secondary fuel into the can body in a state of being mixed with the cooling fluid. 
     
     
         9 . The boiler according to  claim 2 , wherein the secondary fuel supply unit supplies the secondary fuel into the can body downstream of the cooling line in the flow direction of the combustion gas. 
     
     
         10 . The boiler according to  claim 3 , wherein the secondary fuel supply unit supplies the secondary fuel into the can body downstream of the cooling line in the flow direction of the combustion gas. 
     
     
         11 . The boiler according to  claim 2 , wherein the cooling line introduces at least one or more of exhaust gas discharged from the can body, steam, water, and inert gas into the can body as the cooling fluid. 
     
     
         12 . The boiler according to  claim 3 , wherein the cooling line introduces at least one or more of exhaust gas discharged from the can body, steam, water, and inert gas into the can body as the cooling fluid. 
     
     
         13 . The boiler according to  claim 4 , wherein the cooling line introduces at least one or more of exhaust gas discharged from the can body, steam, water, and inert gas into the can body as the cooling fluid.