Wall Construction for a Boiler Arrangement

Abstract

A wall construction for a boiler arrangement. The boiler arrangement is formed of at least a furnace and a separator. The furnace has a grid, a bottom part, and an upper part. The separator is arranged by conduits in flow communication with both the upper part and the bottom part of the furnace. The conduits, together with the separator, form an external circulation of bed material. The upper part of the furnace has four vertical walls, and the bottom part of the furnace has a height and four walls extending from the grid up to the vertical walls. The wall construction includes at least one hollow beam being attached to a wall of the bottom part of the furnace and extending substantially over the entire height of the bottom part, and the at least one hollow beam being in flow communication with the external circulation for returning bed material into the furnace.

1 . A wall construction for a boiler arrangement, the boiler arrangement being formed of at least a furnace and a separator, the furnace having a grid, a bottom part, and an upper part, the separator being arranged by conduits in flow communication with both the upper part and the bottom part of the furnace, the conduits together with the separator forming an external circulation of bed material, the upper part of the furnace having four vertical walls, and the bottom part of the furnace having a height and four walls extending from the grid up to the vertical walls, the wall construction comprising:
 at least one hollow beam being attached to a wall of the bottom part of the furnace and extending substantially over the entire height of the bottom part, and the at least one hollow beam being in flow communication with the external circulation for returning bed material into the furnace.   
     
     
         2 . The wall construction according to  claim 1 , further comprising an opening in the wall of the bottom part of the furnace for receiving bed material from the external circulation, the opening being arranged in flow communication with the at least one hollow beam. 
     
     
         3 . The wall construction according to  claim 1 , wherein the at least one hollow beam extends over at least 80% of the height of the wall of the bottom part of the furnace. 
     
     
         4 . The wall construction according to  claim 1 , wherein the at least one hollow beam is attached, at its lower part, to the grid of the furnace. 
     
     
         5 . The wall construction according to  claim 1 , further comprising a lowermost horizontal reinforcement at the lower end of the vertical wall of the upper part of the furnace, wherein the at least one hollow beam has an upper part, and the beam is attached, at its upper part, to the lowermost horizontal reinforcement. 
     
     
         6 . The wall construction according to  claim 1 , wherein the at least one hollow beam is arranged in flow communication with one of (i) a fluidized bed heat exchange chamber arranged on the vertical wall of the upper part of the boiler, (ii) a fluidized bed heat exchange chamber hanging from the separator, (iii) a fluidized bed heat exchange chamber supported separate from the boiler and the separator, and (iv) a separator. 
     
     
         7 . The wall construction according to  claim 1 , wherein the at least one hollow beam is formed of water/steam tube panels forming at least two side walls and one back wall, the panels being attached to each other and to the wall of the bottom part of the furnace for forming a box-like structure. 
     
     
         8 . The wall construction according to  claim 7 , wherein the back wall of the at least one hollow beam is parallel with the wall of the bottom part of the furnace. 
     
     
         9 . The wall construction according to  claim 7 , wherein the at least one hollow beam has a lower part and a bottom wall is arranged to the lower part of the beam. 
     
     
         10 . The wall construction according to  claim 9 , wherein the bottom wall is arranged between the side walls of the at least one hollow beam. 
     
     
         11 . The wall construction according to  claim 9 , wherein the bottom wall is formed by bending the back wall of the at least one hollow beam between the side walls. 
     
     
         12 . The wall construction according to  claim 9 , wherein the bottom wall of the at least one hollow beam is arranged to slope towards the opening. 
     
     
         13 . The wall construction according to  claim 1 , wherein the at least one hollow beam is formed of two side walls and a back wall, each having two longitudinal edges, the side walls having a longitudinal edge and being attached by their one longitudinal edge to the wall of the bottom part of the furnace and by an opposite longitudinal edge to the longitudinal edges of the back wall, to form a box-like structure. 
     
     
         14 . The wall construction according to  claim 13 , wherein the box-like structure forms a hollow beam. 
     
     
         15 . The wall construction according to  claim 1 , wherein the wall of the bottom part of the furnace has one or more hollow beams acting as substantially vertical reinforcements or buckstays. 
     
     
         16 . A boiler arrangement comprising:
 a furnace having a grid, a bottom part, and an upper part, the upper part of the furnace having four vertical walls, and the bottom part of the furnace having a height and four walls extending from the grid up to the vertical walls;   a separator arranged by conduits in flow communication with both the upper part and the bottom part of the furnace, the conduits together with the separator forming an external circulation of bed material; and   a wall construction comprising at least one hollow beam being attached to a wall of the bottom part of the furnace and extending substantially over the entire height of the bottom part, and the at least one hollow beam being in flow communication with the external circulation for returning bed material into the furnace.   
     
     
         17 . The boiler arrangement according to  claim 16 , further comprising an opening in the wall of the bottom part of the furnace for receiving bed material from the external circulation, the opening being arranged in flow communication with the at least one hollow beam. 
     
     
         18 . The boiler arrangement according to  claim 16 , wherein the at least one hollow beam extends over at least 80% of the height of the wall of the bottom part of the furnace. 
     
     
         19 . The boiler arrangement according to  claim 16 , wherein the at least one hollow beam is attached, at its lower part, to the grid. 
     
     
         20 . The boiler arrangement according to  claim 16 , further comprising a lowermost horizontal reinforcement at the lower end of the vertical wall of the upper part of the furnace, wherein the at least one hollow beam has an upper part, and the beam is attached, at its upper part, to the lowermost horizontal reinforcement. 
     
     
         21 . The boiler arrangement according to  claim 16 , wherein the at least one hollow beam is arranged in flow communication with one of (i) a fluidized bed heat exchange chamber arranged on the vertical wall of the upper part of the boiler, (ii) a fluidized bed heat exchange chamber hanging from the separator, (iii) a fluidized bed heat exchange chamber supported separate from the boiler and the separator, and (iv) a separator. 
     
     
         22 . The boiler arrangement according to  claim 16 , wherein the at least one hollow beam is formed of water/steam tube panels forming at least two side walls and one back wall, the panels being attached to each other and to the wall of the bottom part of the furnace for forming a box-like structure. 
     
     
         23 . The boiler arrangement according to  claim 22 , wherein the back wall of the at least one hollow beam is parallel with the wall of the bottom part of the furnace. 
     
     
         24 . The boiler arrangement according to  claim 22 , wherein the at least one hollow beam has a lower part and a bottom wall is arranged to the lower part of the at least one hollow beam. 
     
     
         25 . The boiler arrangement according to  claim 24 , wherein the bottom wall is arranged between the side walls of the at least one hollow beam. 
     
     
         26 . The boiler arrangement according to  claim 24 , wherein the bottom wall is formed by bending the back wall of the at least one hollow beam between the side walls. 
     
     
         27 . The boiler arrangement according to  claim 24 , wherein the bottom wall of the at least one hollow beam is arranged to slope towards the opening. 
     
     
         28 . The boiler arrangement according to  claim 16 , wherein the at least one hollow beam is formed of two side walls and a back wall, each having two longitudinal edges, the side walls having a longitudinal edge and being attached by their one longitudinal edge to the wall of the bottom part of the furnace and by an opposite longitudinal edge to the longitudinal edges of the back wall, to form a box-like structure. 
     
     
         29 . The boiler arrangement according to  claim 28 , wherein the box-like structure forms a hollow beam. 
     
     
         30 . The wall construction as recited in  claim 16 , wherein the wall of the bottom part of the furnace has one or more hollow beams acting as substantially vertical reinforcements or buckstays.