Method for preventing corrosion on the heat exchange surfaces of a boiler, and a supply means for additional material

Abstract

A supply and a method for preventing corrosion on heat exchange surfaces of a boiler. Additional material is fed to flue gases of a boiler by at least one supply for additional material. The supply includes a cooled case beam that is hollow inside and several nozzles for feeding the additional material.

1 . A method for preventing corrosion on heat exchange surfaces of a boiler, the method comprising:
 feeding additional material to flue gases utilizing a supply for additional material arranged in the flue gases, the supply comprising a cooled case beam that is hollow inside and at least one nozzle for feeding additional material to the flue gases.   
   
   
       2 . The method according to  claim 1 , wherein the supply comprises pipes attached to each other by fins. 
   
   
       3 . The method according to  claim 1 , wherein the additional material is fed to the flue gases in a flow direction of the flue gases before the heat exchange surfaces to be protected from corrosion. 
   
   
       4 . The method according to  claim 3 , wherein the additional material is fed to the flue gases to the temperature area of 650-1000° C. 
   
   
       5 . The method according to  claim 1 , wherein the additional material is iron (III) sulphate, Fe 2 (SO 4 ) 3  and/or aluminum (III) sulphate, Al 2 (SO 4 ) 3 . 
   
   
       6 . The method according to  claim 3 , wherein the additional material comprises a liquid, powdery or gaseous additional material. 
   
   
       7 . The method according to  claim 1 , wherein the additional material is fed to the flue gases via nozzles, which are arranged in at least one row in relation to the length of the supply. 
   
   
       8 . The method according to  claim 1 , wherein additional material is fed to the flue gases to a furnace of the boiler or to a flue gas channel. 
   
   
       9 . The method according to  claim 8 , wherein additional material is fed to the flue gases substantially over the entire cross-sectional area of the furnace or the flue gas channel. 
   
   
       10 . The method according to  claim 1 , wherein the boiler comprises one of the following: a bubbling fluidized bed boiler, a circulating fluidized bed boiler, or a recovery boiler. 
   
   
       11 . A supply of additional material for feeding additional material preventing corrosion to flue gases of a boiler, the supply comprising:
 pipes, in which is arranged a heat exchange medium circulation, the pipes being attached to each other so as to form a case beam that is hollow inside, and   a plurality of nozzles arranged in the beam for feeding the additional material.   
   
   
       12 . The supply according to  claim 11 , further comprising:
 fins configured to attached the pipes to each.   
   
   
       13 . The supply according to  claim 11 , wherein the supply is closed at both ends. 
   
   
       14 . The supply according to  claim 11 , wherein the nozzles are arranged in at least one row in relation to a length of the supply. 
   
   
       15 . The supply according to  claim 11 , wherein the nozzles comprise openings formed in the supply. 
   
   
       16 . The supply according to  claim 11 , wherein the nozzles comprise a feeding duct for additional material, wherein the feeding duct for additional material is surrounded by a feeding duct for shattering air and a carrier air duct, wherein the feeding duct for additional material surrounds the feeding duct for shattering air. 
   
   
       17 . The supply according to  claim 16 , wherein the feeding duct for additional material is connected to a feeding pipe for additional material, and where the feeding duct for shattering air is connected to a feeding pipe for shattering air, wherein the feeding pipe for additional material and the feeding pipe for shattering air are arranged to travel inside the supply. 
   
   
       18 . The supply according to  claim 11 , wherein a length of the supply is selected so that the supply extends between opposite walls of the boiler. 
   
   
       19 . The supply according to  claim 11 , wherein the length of the supply is selected so that the supply extends between opposite walls of a flue gas channel. 
   
   
       20 . The supply according to  claim 18 , wherein the supply is arranged in the flue gases in a flow direction of flue gases before heat exchange surfaces to be protected from corrosion. 
   
   
       21 . The supply according to  claim 20 , wherein the supply means is arranged in the flue gases to the temperature area of 650-1000° C. 
   
   
       22 . The supply according to  claim 11 , wherein the additional material comprises iron (III) sulphate, Fe 2 (SO 4 ) 3  and/or aluminum (III) sulphate, Al 2 (SO 4 ) 3 . 
   
   
       23 . The supply according to  claim 22 , wherein the additional material is liquid, powdery or gaseous. 
   
   
       24 . The supply according to  claim 11 , wherein the boiler comprises one of the following: a bubbling fluidized bed boiler, a circulating fluidized bed boiler, or a recovery boiler.