Simultaneous Control of Hg(o), SO2, and NOx by Novel Oxidized Calcium-BasedSorbents

摘要

The paper gives results of an investigation of two classes of calcium (Ca)-basedsorbents (hydrated limes and silicate compounds). (NOTE: Efforts to develop multipollutant control strategies have demonstrated that adding certain oxidants to different classes of Ca-based sorbents significantly improves the removal of elemental mercury vapor (Hgo), sulfur dioxide (SO2), and nitrogen oxides (NO-x) from simulated flue gases). A number of oxidizing additives were used at different concentrations in the Ca-based sorbent process. The Hgo, SO2, and NO-x capture capacities of these oxidant-enriched sorbents were evaluated and compared to those of a commercially available activated carbon in bench-scale, fixed-bed, and fluid-bed systems. Ca-based sorbents prepared with two oxidants, designated C and P, exhibited Hgo sorption capacities (about 100 ug/g) comparable to that of the activated carbon; they showed far superior SO2 and NO-x sorption capacities. Preliminary cost estimates for the process utilizing these novel sorbents indicate potential for substantial lowering of Hgo, SO2, and NO-x emissions from coal-fired boilers. The implications of these findings toward development of multipollutant control technologies are summarized.