Removal of sulfur from carbonaceous fuels

Claim 2

A PROCESS FOR REDUCING THE SULFUR CONTENT OF NATURALLYOCCURING, SULFUR-CONTAINING, SOLID CARBONACEOUS FUEL TO LESS THAN 1.0 PERCENT, COMPRISING REACTING SAID FUEL IN PARTICULATE FORM UNDER A PRESSURE OF AT LEAST 2 ATMOSPHERES WITH AN OXYGEN-CONTAINING GAS AND WITH STEAM IN A REACTION ZONE, THE AMOUNT OF OXYGEN-CONTAINING GAS BEING JUST SUFFICIENT TO BURN A PORTION OF SAID FUEL TO RAISE THE TEMPERATURE OF THE FUEL IN SAID ZONE TO ABOUT 1100* TO 1500*F. AND THE STEAM BEING PRESENT IN AN AMOUNT SUFFICIENT TO REACT WITH THE FUEL PARTICLES TO GENERATE NASCENT HYDROGEN AT THE SURFACE AND WITHIN SAID PARTICLES AND FORM HYDROGEN SULFIDE WITH THE SULFUR THEREIN, REMOVING THE SULFUR CONTAINING GASES FROM SAID ZONE AND RECOVERING THE FUEL OF REDUCED SULFUR CONTENT.

Claim 3

The process of claim 1 wherein the pressure in the reaction zone is between 2 and 6 atmospheres.

Claim 4

The process of claim 1 wherein no more than about 14% of the fuel is consumed by the reaction with oxygen and steam.

Claim 5

The process of claim 1 wherein the fuel is a bituminous coal and wherein the recovered desulfurized coal retains at least 10 percent volatile matter.

Claim 6

The process of claim 1 wherein the residence time of the fuel in the reactor is less than about 12 minutes.

Claim 7

The process of claim 1 wherein the amount of hydrogen in contact with the fuel is about 4 to 5 times the amount theoretically required to react with all of the sulfur in the fuel to form H2S.

Claim 8

The process of claim 1 wherein the fuel is bituminous coal, the temperature in the reaction zone is from about 1100* to 1500*F and the residence time of the coal particles in the reaction zone is from about 8 to 10 minutes.

Claim 9

The process of claim 1 wherein the fuel is subbituminous coal, the temperature in the reaction zone is about 900* to 1400*F and the residence time of the coal particles in the reaction zone is from about 4 to 8 minutes.

Claim 10

The process of claim 1 wherein the sulfur containing gases are purified to remove sulfur and the purified tail gas which is substantially free of sulfur is recycled to the reaction zone to maintain the sulfur content of the gases in this zone between about 0.1 to 0.5 volume percent.

Claim 11

The process of claim 1 wherein the recovered fuel without substantial reduction in temperature is reacted in a separate reaction zone to generate heat or produce fuel gases.

Claim 12

The process of claim 1 wherein the recovered fuel is gasified in a separate reaction zone to produce low sulfur fuel gases.

Claim 13

The process of claim 11 wherein the sulfur containing gases produced in the initial reaction zone are purified to remove sulfur and are introduced into said separate reaction zone with the recovered sulfur free fuel.

Claim 14

The process of claim 11 wherein the sulfur containing gases produced in the initial reaction zone are purified to remove sulfur and are combined with the gases from said separate reaction zone.

Claim 15

The process of claim 11 wherein the separate reaction zone is under a pressure of 2 to 300 atmospheres, the pressure in the initial reaction zone is at least as high as that of said separate reaction zone, and the hot desulfurized fuel is transferred from said first reaction zone to the separate reaction zone without substantial loss of temperature or pressure.

Claim 16

The process of claim 1 wherein the oxygen containing gas is air.

Claim 17

The process of claim 1 wherein the oxygen containing gas is oxygen or oxygen enriched air.

Claim 18

A process for desulfurizing sulfur-containing coal comprising reacting said coal in particulate form with oxygen and steam in a reaction zone under a pressure of at least 2 atmospheres, the amount of oxygen being just sufficient to burn a portion of the coal to raise the temperature in said zone to about 900* to 1500*F and the amount of steam being sufficient to react with the coal to generate nascent hydrogen in contact with the coal, the amOunt of hydrogen including that generated by the steam reaction and that present in the coal being about 4 to 5 times that theoretically required for reaction with all of the sulfur in the coal to produce H2S, removing the sulfur-containing gases from said zone, purifying said sulfur-containing gases to provide a substantially sulfur-free tail gas, recycling the sulfur free tail gas to said reaction zone to maintain the sulfur content of the gases in contact with the coal below about 0.5 volume percent, and removing the desulfurized coal from said zone after a residence time of less than about 12 minutes.

Claim 19

A process for desulfurizing sulfur-containing coal comprising reacting said coal in particulate form with oxygen and steam in a reaction zone under a pressure of at least 2 atmospheres, the amount of oxygen being just sufficient to burn a portion of the coal to raise the temperature in said zone to about 900* to 1500*F and the amount of steam being sufficient to react with the coal to generate nascent hydrogen in contact with the coal, the amOunt of hydrogen including that generated by the steam reaction and that present in the coal being about 4 to 5 times that theoretically required for reaction with all of the sulfur in the coal to produce H2S, removing the sulfur-containing gases from said zone, purifying said sulfur-containing gases to provide a substantially sulfur-free tail gas, recycling the sulfur free tail gas to said reaction zone to maintain the sulfur content of the gases in contact with the coal below about 0.5 volume percent, and removing the desulfurized coal from said zone after a residence time of less than about 12 minutes.