To increase an interior space for installing a group of inside-bed heat transfer tubes, while achieving compactness of an entire fluidized bed furnace, by forming a bulkhead in substantially a cylindrical shape, and forming a combustion portion at the inner peripheral side thereof and a ring-shaped heat recovery portion at the outer peripheral side thereof.
A secondary combustion chamber 1B is provided at an upper part, and a fluidized bed 1A is provided at a lower part. The fluidized bed 1A is formed concentrically as having a longer diameter in comparison with the upper secondary combustion chamber 1B. A bulkhead 3 for separating a combustion portion 10 from a heat recovery portion 2 is formed substantially in a cylindrical shape. The combustion portion 10 is provided at the inner peripheral side of the bulkhead 3, and the ring-shaped heat recovery portion 2 is provided at the outer peripheral side thereof. Inside-bed heat transfer tubes 4 are, respectively, inserted into the heat recovery portion 2 from four directions of left and right, and top and bottom so that fluidized air is fed at a superficial velocity U1 in the tubes downward of the central portion of the combustion portion 10 side, and at a superficial velocity U2 downward of the ring-shaped peripheral side of the heat recovery portion 2 side, respectively, while making a difference between velocities (U1>U2).
HONDA HIROKI
SHIMIZU YOSHIHITO
ARAOKA MAMORU
OKUNO SATOSHI
