Coal combustion to produce clean low-sulfur exhaust gas

Claim 1

The process for combusting sulfur-containing coal while producing of off-gas low in sulfur which comprises combusting particulate coal in a furnace burner cavity providing rapid coal combustion, a hot, turbulent combustion zone and a combustion temperature of at least about 1100° C. in the presence of a finely divided sulfur-fixing material from the group consisting of iron oxide, iron powder and copper oxide in amounts about 25% to about 100% in excess of the stoichiometric quantity required to produce metal sulfide based on the sulfur content of said coal distributed throughout said combustion zone and at least about 60% of the oxygen stoichiometrically required for complete combustion of said coal to form a particulate liquid oxysulfide phase within a turbulent atmosphere of combustion-product gases, said liquid oxysulfide acting to scrub sulfur-containing gaseous species from said atmosphere to yield an essentially sulfur-free flue gas and a liquid oxysulfide slag containing essentially all the sulfur originally contained in said coal.

Claim 16

The method for combusting sulfur-containing coal while producing a substantially sulfur-free combustion-product gas and fixing essentially all the sulfur content of said coal in a sulfidic slag which comprises mixing the sulfur-containing coal to be combusted with a finely-divided sulfur-fixing material from the group consisting of iron oxide, iron powder and copper oxide, said sulfur-fixing material being stoichiometrically in excess of the sulfur content of said coal and combusting said mixture along with at least about 60% of the oxygen stoichiometrically required for complete combustion of said coal in a turbulent combustion zone at a temperature of about 1100° C. to about 1500° C. wherein high combustion gas velocities are maintained and wherein the particles of said sulfur-fixing material rapidly incandesce and react with gaseous sulfur species in said combustion gas to form a myriad of liquid oxysulfide particles which scrub sulfur-containing species from said combustion zone to yield an essentially sulfur-free combustion-product gas and a liquid oxysulfide slag containing essentially all the sulfur originally contained in said coal.

Claim 17

The method for combusting sulfur-containing coal while producing a substantially sulfur-free combustion-product gas and fixing essentially all the sulfur content of said coal in a sulfidic slag which comprises mixing the sulfur-containing coal to be combusted with a finely-divided sulfur-fixing material from the group consisting of iron oxide, iron powder and copper oxide, said sulfur-fixing material being stoichiometrically in excess of the sulfur content of said coal and combusting said mixture along with at least about 60% of the oxygen stoichiometrically required for complete combustion of said coal in a turbulent combustion zone at a temperature of about 1100° C. to about 1500° C. wherein high combustion gas velocities are maintained and wherein the particles of said sulfur-fixing material rapidly incandesce and react with gaseous sulfur species in said combustion gas to form a myriad of liquid oxysulfide particles which scrub sulfur-containing species from said combustion zone to yield an essentially sulfur-free combustion-product gas and a liquid oxysulfide slag containing essentially all the sulfur originally contained in said coal.