Fluidized bed heat exchanger with water cooled air distributor and dust hopper

Claim 2

A fluidized bed heat exchanger comprising a housing, a reaction chamber within the housing, means for introducing air into said reaction chamber including a windbox region below said reaction chamber and an air distributor therebetween, an integral water-cooled floor and bridgewall assembly in said housing, a convection heat exchange chamber above said reaction chamber within said housing and separated from said reaction chamber by a slanted baffle, said baffle defining a gas passageway between said reaction chamber and said convection heat exchange chamber and having a hopper portion whereby dust is collected and removed from gases passing through said convection heat exchange chamber, means for establishing a bed of particulate material containing fuel in said reaction chamber, said bed of particulate material being subject to fluidization by air passing into said reaction chamber from said windbox region through said air distributor, a steam drum in said convection heat exchange chamber, an array of tubes each connected at one end to said steam drum and passing through said reaction chamber and into and through said air distributor to connect with a header, said array of tubes having a vertical orientation in that portion of the reaction chamber occupied by said fluidized bed of particulate material, the walls of said housing in the region of said reaction chamber being water-cooled, said integral water-cooled floor and bridgewall assembly formed to provide said air distributor, one of said housing walls, and said baffle, valve controlled conduit means within said housing and extending from said hopper portion of said baffle to a discharge port opening into said reaction chamber below the upper surface of said fluidized bed.

Claim 3

The fluidized bed heat exchanger of claim 1 wherein the arrangement of water-carrying tubes is such as to provide natural circulation of the water.

Claim 4

The fluidized bed heat exchanger of claim 2 wherein said windbox region has at least two independent windbox chambers each associated with a separate group of tuyeres in said air distributor so that a selected portion of said bed of particulate material may be permitted to slump by not supplying air to one of said windbox chambers while the balance of said bed is fluidized by supply of air to the windbox chamber therebelow.

Claim 5

The fluidized bed heat exchanger of claim 3 wherein a plurality of jet nozzles are provided in said housing in the region of said reactor chamber to direct a stream of air laterally at a slumped portion of said bed to prevent excessive accumulation of particulate material on said slumped bed.

Claim 6

A fluidized bed heat exchanger comprising a housing, means for introducing fuel and air into said housing for combustion therein, said housing having therein a unitary floor and bridgewall assembly, said unitary floor and bridgewall assembly defining and separating within said housing a combustion chamber, a windbox region below said combustion chamber and a convection heat exchange chamber above said combustion chamber, said unitary floor and bridgewall assembly comprising a skeletal array of coolant tubes for circulation of a coolant therethrough to prevent overheating of said assembly, the surfaces of said assembly which are exposed in said combustion and convection chambers having a protective layer of refractory thereon, a floor portion of said unitary floor and bridgewall assembly having perforations therethrough constituting an air distributor for air traversing said perforations from said windbox to said combustion chamber, a baffle portion of said unitary floor and bridgewall assembly having a sloped orientation within said housing, and, at the upper end thereof, defining a gas port between the edge of said baffle portion and one wall of said housing to accommodate the gases flowing from said combustion chamber to said convection chamber, a wall portion of said unitary floor and bridgewall assembly forming one wall of said combustion chamber and joining said floor portion to said baffle portion so that cooling water may be circulated successively through the coolant tubes of said floor portion, said wall portion and said baffle portion, the upper section of said baffle portion forming a planar baffle and the lower section forming a v-shaped hopper so that dust dropped by the exhaust gas in said convection chamber slides down the planar baffle and is channeled by the hopper to a conduit for removal from said convection chamber and heat exchange means in said housing for extracting heat from the combustion gases generated therein.

Claim 7

A fluidized bed heat exchanger comprising a housing, means for introducing fuel and air into said housing for combustion therein, said housing having therein a unitary floor and bridgewall assembly, said unitary floor and bridgewall assembly defining and separating within said housing a combustion chamber, a windbox region below said combustion chamber and a convection heat exchange chamber above said combustion chamber, said unitary floor and bridgewall assembly comprising a skeletal array of coolant tubes for circulation of a coolant therethrough to prevent overheating of said assembly, the surfaces of said assembly which are exposed in said combustion and convection chambers having a protective layer of refractory thereon, a floor portion of said unitary floor and bridgewall assembly having perforations therethrough constituting an air distributor for air traversing said perforations from said windbox to said combustion chamber, a baffle portion of said unitary floor and bridgewall assembly having a sloped orientation within said housing, and, at the upper end thereof, defining a gas port between the edge of said baffle portion and one wall of said housing to accommodate the gases flowing from said combustion chamber to said convection chamber, a wall portion of said unitary floor and bridgewall assembly forming one wall of said combustion chamber and joining said floor portion to said baffle portion so that cooling water may be circulated successively through the coolant tubes of said floor portion, said wall portion and said baffle portion, the upper section of said baffle portion forming a planar baffle and the lower section forming a v-shaped hopper so that dust dropped by the exhaust gas in said convection chamber slides down the planar baffle and is channeled by the hopper to a conduit for removal from said convection chamber and heat exchange means in said housing for extracting heat from the combustion gases generated therein.

Claim 8

The fluidized bed heat exchanger of claim 5 wherein all walls of said combustion chamber are water-cooled.

Claim 9

The fluidized bed heat exchanger of claim 6 wherein said heat exchange means includes a plurality of vertically disposed heat exchange tubes in said combustion chamber remote from said walls.

Claim 10

The fluidized bed heat exchanger of claim 7 wherein said heat exchange tubes in said combustion chamber are connected to a steam drum in said convection chamber.

Claim 11

The fluidized bed heat exchanger of claim 8 wherein said windbox region has at least two independent windbox chambers each associated with a separate group of tuyeres in said air distributor so that each group of tuyeres may be selectively utilized.

Claim 12

The fluidized bed heat exchanger of claim 9 wherein a plurality of jet nozzles are provided in said housing in the region of said reactor chamber to direct a stream of air laterally at a predetermined level above said air distributor.