Abstract: The Low Temperature Mercury Control, or LTMC, process is a technology developed by us for controlling mercury emissions from coal-fired power plants. In the LTMC process, mercury emissions are controlled by cooling the exhaust flue gases with an air heater (or water spray) beyond the typical 300° F. to about 200-220° F., thereby promoting mercury absorption on the coal fly ash. The fly ash containing the absorbed mercury is then captured in the power plant's existing particulate collection device. An alkaline material, magnesium hydroxide slurry in our tests, is injected to eliminate sulfur trioxide (sulfuric acid) which could otherwise condense at the cool temperature and corrode or foul the power plant's air heater and ductwork.

Abstract: In flue gas desulfurization, sorbent promoters are recovered by mixing collected particulates with water to form a slurry. The slurry is dewatered and wet solids are disposed. The recovered material contains water soluble desulfurization promoters and is reinjected in a flue gas desulfurization humidification system. The recycle allows recovery of water soluble promoters and reduces consumption. In addition, for promoters having undesirable disposal characteristics, the system improves the disposal characteristics of the waste solids.

Abstract: Flue gas is desulfurized by mixing into the combustion zone a finely divided sorbent such as calcium carbonate and, downstream of the mixing point, reactivating the sorbent by spraying the gaseous suspension with an aqueous solution of solubilizing agent such as a deliquescent compound or a strongly ionizing inorganic salt.

Abstract: Flue gas is desulfurized by mixing into it at a temperature between about 120.degree. and about 230.degree. C. a finely divided sorbent such as calcium hydroxide and, immediately downstream of the mixing point, spraying the gaseous suspension with an aqueous solution of solubilizing agent such as a deliquescent compound or a strongly ionizing inorganic salt. In one embodiment, make-up sorbent is derived from injection of limestone or dolomite into the combustion zone, and in another embodiment a portion of the solids separated from the flue gas is reactivated for reuse as sorbent.