Method of burning sulfur-containing fuels in a fluidized bed boiler

Claim 1

In a method of burning a sulfur-containing coal, of the type wherein the sulfur-containing coal is fed to a fluidized bed of particulate material containing sulfur oxide sorbent and burned therein in close association with the sulfur oxide sorbent; and wherein particulate matter, including spent sulfur oxide sorbent, is periodically or continuously drained from the bed, the improvement comprising: a. comminuting the particulate matter drained from the bed to a smaller particle size, thereby fracturing the spent sulfur oxide sorbent included therein so as to expose unreacted sulfur oxide absorbing surface; b. mixing the comminuted particulate matter, including the fractured particles of spent sulfur oxide sorbent having newly-exposed unreacted sulfur oxide sorption surface, with the sulfur-containing coal being fed to the fluidized bed, thereby establishing intimate contact between the sulfur-containing coal and the newly-exposed sulfur oxide sorption surface; c. heating said mixture of comminuted particulate matter with the sulfur-containing coal so as to effect the agglomeration of the coal in said mixture thereby fusing the comminuted particulate matter in intimate contact with the sulfur-containing coal; and d. injecting said fused mixture of comminuted particulate matter and sulfur-containing fuel into the bed.

Claim 5

A method as recited in claims 1, 2, or 3 wherein the step of comminuting the particulate matter drained from the bed to a smaller particle size comprises comminuting said particulate material to an average particle size of less than approximately 100 microns.

Claim 7

A method as recited in claims 1, 2, or 3 wherein the sulfur oxide sorbent is selected from the group consisting of limestone, dolomite, and soda ash.