Reducing mercury emissions from the burning of coal
Calcium bromide is a component of sorbent compositions that can be added on to coal to reduce the amount of sulfur gases released into the atmosphere from a coal burning facility. The sorbent components are added onto coal before the coal is added into the furnace and combusted. The fuel being burned is any fuel that contains sulfur, such as lignite, bituminous, and anthracite coal. The sorbent can contain other components such as silica, alumina, cement kiln dust, lime kiln dust, Portland cement, and aluminosilicate clay. Sulfur emissions are monitored during combustion of the fuel, and the rate of sorbent addition can be changed or a adjusted based on the monitored sulfur levels.
1. A method for reducing the amount of sulfur gases released into the atmosphere from a coal burning plant, comprising
adding a sorbent to the coal prior to combustion;
delivering the coal into a furnace;
burning the coal in the furnace to produce ash and flue gases; and
measuring the level of sulfur gases in the flue gas;
wherein the sorbent comprises calcium bromide.
2. A method according to claim 1 , wherein the coal is lignite coal.
3. A method according to claim 1 , wherein the coal is bituminous coal.
4. A method according to claim 1 , wherein the coal is anthracite coal.
5. A method according to claim 1 , further comprising controlling the rate of the sorbent addition based on the level of sulfur gases determined in the flue gas.
6. A method according to claim 1 , comprising adding 1 to 9% by weight of sorbent based on the amount of coal being consumed.
7. A method according to claim 1 , comprising adding an aqueous solution of calcium bromide onto the coal.
8. A method according to claim 7 , comprising delivering the coal to the furnace while the coal is still wet from addition of the aqueous solution.
9. A method according to claim 1 , wherein the sorbent further comprises at least 2% by weight of silica and at least 2% by weight of alumina.
10. A method according to claim 1 , wherein the sorbent comprises at least one of cement kiln dust, lime kiln dust, and Portland cement.
11. A method according to claim 10 , wherein the sorbent further comprises aluminosilicate clay.