Regenerable Catalytic Sorbents for the Removal of Mercury from Flue Gas

The proposed program addresses the removal of elemental mercury and sulfur oxides from coal-fired utility boiler flue gas by catalytic oxidative adsorption on a regenerable substrate. This proposal concentrates on the preparation, characterization, and testing of metal oxide and metal oxysulfide sorbents. An oxidation-promoting substrate will be modified to selectively and reversibly bind Hg0 in the exhaust stream of coal-fired power plants. Upon saturation of the sorbent bed active sites, it is expected that the sorbent bed will be regenerated and the mercury collected in a form suitable for either recycling or disposal. Thus, the proposed technology is ideal for online continuous mercury emission control in coal-fired power plants. The use of a regenerable sorbent is an economical solution to the problem of mercury emission control in coal-fired power plants because of the reduced cost compared with direct-injection schemes, and because of easy recycling or disposal of the mercury collected. Coal-fired utilities account for 56 percent of the energy produced in the United States each year, and a 100-megawatt plant emits about 100 lbs of mercury during that time period. The insidious nature of mercury contamination in the environment eventually will lead to increased regulation of coal-fired power plants, so the market for an inexpensive and effective mercury abatement technology is anticipated to be quite large. An economical solution, such as the one proposed here, would be attractive to the entire coal-power industry. Municipal solid waste incinerators are another large and growing source of mercury emissions that would be amenable to inexpensive mercury emissions control technology. Additionally, other sources of fossil fuel combustion emissions, such as diesel- and gasoline-powered engines, may eventually be served by an effective and inexpensive mercury emissions control technology.