CIRCULATING FLUIDIZED BED COMBUSTION FURNACE

PROBLEM TO BE SOLVED: To reduce depth of wear in a plurality of steam generating tubes in the vicinity of the upper surface of a lower refactory material, in a circulating fluidized bed combustion furnace which comprises the steam generating tubes disposed on a wall surface, and the lower refactory material provided to the lower part of the wall surface and constituted so that particles of a fluid material descends along the wall surface. SOLUTION: In the circulating fluidized bed combustion furnace, a wall surface is formed by a plurality of steam generating tubes 2 which are connected with each other through a partitioning wall 2'. The lower part of the wall surface is provided with a lower refactory material 3. The tubes 2 are bent outward at an upper part of the material 3 and restored to the original position at the part where the material 3 is provided. The material 3 is bent outward and comprises a vertical surface which is positioned at the same vertical position as the wall 2' provided between the tubes 2 at the front.