Fluidized bed reactor and method of operating same

Claim 3

The method of claim 1 wherein said air is introduced in quantities below that required for complete combustion of said fuel, and further comprising the step of introducing an additional quantity of air to said vessel at a location above the area of introduction of said first quantity of air, the quantity of said additional air being sufficient to completely combust said fuel.

Claim 4

The method of claim 1 further comprising the step of varying the relative portions of separated fine particles returned back to the vessel and separated fine particles discharged to eternal equipment to vary the relative portions of relative fine particles and relatively coarse particles in said bed.

Claim 5

The method of claim 1 further comprising the step of controlling the temperature of said bed by varying the quantity of air introduced to said vessel.

Claim 6

The method of claim 1 further comprising the step of circulating water through said vessel to absorb the heat from said combustion and convert said water to steam.

Claim 7

The method of claim 1 further comprising the steps of discharging spent particles from said bed and varying the rate of said discharge or spent particles to adjust the residence time of said particles in said vessel.

Claim 8

The method of claim 1 wherein the quantity of said fine particles introduced into and returned to said vessel is controlled so that the ratio of relatively fine particles to relatively coarse Particles varies from 55-45 to 93-7 by weight.

Claim 9

The method of claim 1 wherein the quantity of said coarse materials and fine materials introduced to said vessel and the quantity of said fine materials returned to said vessel are controlled so that the volume of said bed occupied by said particles is approximately 20-30% of the total volume of said vessel and is substantially the same in all fluidized bed locations.

Claim 10

A fluidized bed reactor comprising means for introducing relative coarse and relatively fine solid fuel particles into a vessel for combustion, means for introducing air into said vessel and through said particles to fluidize said Particles and support said combustion, means for controlling the velocity of said air so that it is sufficient to entrain the relatively fine particles and insufficient to entrain the relatively coarse particles so that said coarse particles form a discrete fluidized bed in the lower portion of said vessel, said vessel being constructed and arranged so that said air and entrained fine particles mix with the gaseous products of combustion and rise upwardly in said vessel, means for separating said fine particles from said mixture, means for dividing said separated fine particles into two portions, means for returning one portion of said separated fine particles back to said vessel, means for discharging the other portion of separated fine particles to external equipment, means for controlling the quantity of said fine particles introduced into said vessel and returned to said vessel so that they are in excess of that sufficient to saturate the gases in said mixture so that a portion of said fine particles accumulates in said discrete bed of coarse particles.

Claim 11

A fluidized bed reactor comprising means for introducing relative coarse and relatively fine solid fuel particles into a vessel for combustion, means for introducing air into said vessel and through said particles to fluidize said Particles and support said combustion, means for controlling the velocity of said air so that it is sufficient to entrain the relatively fine particles and insufficient to entrain the relatively coarse particles so that said coarse particles form a discrete fluidized bed in the lower portion of said vessel, said vessel being constructed and arranged so that said air and entrained fine particles mix with the gaseous products of combustion and rise upwardly in said vessel, means for separating said fine particles from said mixture, means for dividing said separated fine particles into two portions, means for returning one portion of said separated fine particles back to said vessel, means for discharging the other portion of separated fine particles to external equipment, means for controlling the quantity of said fine particles introduced into said vessel and returned to said vessel so that they are in excess of that sufficient to saturate the gases in said mixture so that a portion of said fine particles accumulates in said discrete bed of coarse particles.

Claim 12

The reactor of claim 9 wherein said air introducing means comprises first air discharge means for introducing air into said bed in quantities below that required for complete combustion of said fuel so that the combustion of said fuel in said bed is incomplete, and second air discharge means for supplying additional air to said mixture above said bed in quantities sufficient to completely combust said fuel.

Claim 13

The reactor of claim 9 further comprising means for varying the relative portions of separated fine particles returned back to the vessel and separated fine particles discharged to external equipment to vary the relative portions of relative fine particles and relatively coarse particles in said bed.

Claim 14

The reactor of claim 9 further comprising means for controlling the temperature of said bed by varying the quantity of air introduced to said vessel.

Claim 15

The reactor of claim 9 further comprising means for circulating water through said vessel to absorb the heat from said combustion and convert said water to steam.

Claim 16

The reactor of claim 9 further comprising means for discharging spent particles from said bed, and means for varying the rate of said discharge of said spent particles to adjust the residence time of said particles in said vessel.