TREATMENT OF COAL WITH MERCURY CONTROL ADDITIVES
A method of treating coal that is combusted in a combustion chamber at a coal-combustion facility that includes adding an additive to the coal for mercury emissions control. The adding of the additive to the coal is performed before the coal enters the combustion chamber. The additive includes Br 2 , I 2 , a bromide compound, an iodide compound, HBr, HI, or a combination thereof.
1 . A method of treating coal that is combusted in a combustion chamber at a coal-combustion facility, the method comprising:
adding an additive to the coal, wherein the adding of the additive to the coal is performed at the coal-combustion facility before the coal enters the combustion chamber, and the additive comprises Br 2 , I 2 , a bromide compound, an iodide compound, HBr, HI, or a combination thereof.
2 . The method of claim 1 , wherein the adding of the additive to the coal at the coal-combustion facility comprises adding the additive to the coal during conveyance of the coal to the combustion chamber.
3 . The method of claim 1 , wherein the additive comprises the Br 2 , I 2 , or a combination thereof.
4 . The method of claim 1 , wherein the additive comprises the bromide compound, HBr, or a combination thereof.
5 . The method of claim 1 , wherein the additive comprises the bromide compound.
6 . The method of claim 1 , wherein the additive comprises the iodide compound, HI, or a combination thereof.
7 . The method of claim 1 , wherein the additive comprises the iodide compound.
8 . The method of claim 1 , wherein the coal comprises mercury.
9 . The method of claim 1 , wherein the combustion chamber is an electric utility coal combustion chamber.
10 . The method of claim 1 , wherein the coal combustion facility is a coal gasification combustion chamber.
11 . The method of claim 1 , wherein the combustion chamber is a coal combustion furnace.
12 . The method of claim 1 , wherein the combustion chamber comprises a boiler.
13 . The method of claim 1 , wherein the combustion chamber comprises a boiler for burning pulverized coal.
14 . The method of claim 1 , wherein combustion of the coal in the combustion chamber forms a mercury-containing flue gas that flows to a downstream portion of the coal-combustion facility, the downstream portion comprising a mercury removal system for removal of elemental mercury, oxidized mercury, or a combination thereof, from the flue gas.
15 . The method of claim 14 , wherein the downstream portion comprises a sorbent injection system for injecting a sorbent into the flue gas.
16 . The method of claim 15 , wherein the coal-combustion facility comprises a mercury emissions monitoring system that measures the mercury content of the flue gas and modifies, in response to the measured mercury content of the flue gas, an injection rate of injecting the sorbent into the flue gas, an amount of the additive added to the coal, or a combination thereof, so that the mercury content of the flue gas is maintained at or below a desired level.
17 . The method of claim 14 , wherein the coal-combustion facility comprises a system that measures mercury content and modifies, in response to the measured mercury content, an injection rate of injecting a sorbent into the flue gas, an amount of the additive added to the coal, or a combination thereof.
18 . The method of claim 15 , wherein the sorbent comprises activated carbon.
19 . The method of claim 14 , wherein the downstream portion comprises a sorbent injection system for injecting a sorbent into the flue gas, a particulate removal system, a scrubber, or a combination thereof.
20 . The method of claim 19 , wherein the particulate removal system comprises an electrostatic precipitator, a baghouse, a fabric filter, or a combination thereof.
21 . The method of claim 15 , wherein the sorbent injection system injects sorbent into the flue gas before the flue gas encounters a particulate removal system, a scrubber, or a combination thereof.
22 . The method of claim 1 , wherein the additive is added to the coal at the coal-combustion facility between a coal pulverizer and the combustion chamber.
23 . The method of claim 1 , wherein the additive is added to the coal at the coal-combustion facility in a pulverizer.
24 . The method of claim 1 , wherein the additive is added to the coal before the coal enters a pulverizer.
25 . The method of claim 1 , wherein the coal is a pulverized coal.
26 . The method of claim 1 , wherein the coal comprises a subbituminous coal.
27 . The method of claim 1 , wherein the coal comprises a lignite coal.
28 . A method of treating coal that is combusted in a combustion chamber at a coal-combustion facility, the method comprising:
adding an additive to the coal, wherein the adding of the additive to the coal is performed at the coal-combustion facility before the coal enters the combustion chamber, and the additive comprises bromine, bromide, HBr, iodine, iodide, HI, or a combination thereof.
29 . A method of treating coal for combustion in a combustion at a coal-combustion facility, the method comprising:
adding an additive to the coal, wherein the adding of the additive to the coal is performed at the coal-combustion facility before the coal enters the combustion chamber, and the additive comprises Br 2 , I 2 , a bromide compound, an iodide compound, HBr, HI, or a combination thereof;
wherein combustion of the coal in the combustion chamber forms a mercury-containing flue gas that flows to a downstream portion of the coal-combustion facility; and
wherein the coal-combustion facility comprises a system that measures mercury content and modifies, in response to the measured mercury content, an injection rate of injecting a sorbent into the flue gas, an amount of the additive added to the coal, or a combination thereof.
30 . A method of treating coal for combustion in a combustion chamber at a coal-combustion facility, the method comprising:
adding an additive to the coal, wherein the adding of the additive to the coal is performed at a site other than the coal-combustion facility, and the additive comprises Br 2 , I 2 , a bromide compound, an iodide compound, HBr, HI, or a combination thereof;
wherein combustion of the coal in the combustion chamber forms a flue gas that flows to a downstream portion of the coal-combustion facility, the downstream portion comprising
a scrubber,
a particulate removal system,
a sorbent injection system for injecting a sorbent into the flue gas, or
a combination thereof, and
wherein the coal-combustion facility comprises a system that measures mercury content and modifies, in response to the measured mercury content, an injection rate of injecting a sorbent into the flue gas, an amount of the additive added to the coal, or a combination thereof.