Patent ID: 8372362

Claim:
A method, comprising: in a mercury-containing gas stream comprising vapor-phase mercury and vapor-phase iodine and having a temperature ranging from about 325 to about 450° C., the vapor-phase iodine being derived, at least in part, from an iodine-containing additive, separating at least about 50% of the vapor-phase mercury from the mercury-containing gas stream, wherein at least one of the following is true: (i) the mercury-containing gas stream comprises about 3.5 ppmw or less vapor-phase iodine; (ii) in the mercury-containing gas stream, a molar ratio of vapor-phase iodine to vapor-phase mercury is no more than about 600; (iii) at an air preheater outlet, a concentration of vapor-phase iodine ranges from about 0.1 to about 10 ppmw; and (iv) a concentration of the vapor-phase iodine is about 30 ppmw or less relative to a weight of a solid mercury-containing feed material producing the vapor-phase mercury.