Method and apparatus for removing mercury from a flue gas stream
AssigneeThe Babcock & Wilcox Company
InventorsSteven Feeney, Mandar R Gadgil
Life of this patent
Estimating the term…
Abstract
The present invention relates generally to the field of emission control equipment for boilers, heaters, kilns, or other flue gas-, or combustion gas-, generating devices (e.g., those located at power plants, processing plants, etc.) and, in particular to a new and useful method and apparatus for capturing, oxidizing, lowering the concentration and/or level of, and/or eliminating mercury present in any flue gas and/or combustion gas stream. In one embodiment, the method and/or apparatus of the present invention is applied to boilers, heaters, kilns, or other flue gas-, or combustion gas-, generating devices that have connected thereto at least one type of flue gas, or combustion gas, scrubber device (i.e., a wet scrubber or a dry scrubber).
Claims57
A method for oxidizing elemental mercury present in a flue gas, or combustion gas, stream wherein the method comprises the steps of:
- (I) burning at least one fuel so as to yield a mercury-containing flue gas, or combustion gas, stream wherein at least a portion of the mercury in the mercury-containing flue gas, or combustion gas, stream is elemental mercury;
- (II) injecting one or more halogen-containing compounds into the mercury-containing flue gas, or combustion gas, stream in order to oxidize at least a portion of the elemental mercury in the mercury-containing flue gas, or combustion gas, stream into oxidized mercury and form one or more corresponding mercury halide compounds;
- (III) injecting one or more sulfur-containing compounds and/or sulfide salt compounds into at least one air quality control device in order to convert the one or more mercury halide compounds into one or more mercury-sulfur compounds that is, or are, insoluble in an aqueous environment or an aqueous-based environment;
- (IV) supplying at least one control device and one or more real-time mercury sensing devices, or sensors, wherein the at least one control device is operatively connected to the one or more real-time mercury sensing devices, or sensors, in order to provide real-time data on at least two of:
- (i) oxidized mercury concentration level in the flue gas, or combustion gas, stream, (ii) elemental mercury concentration level in the flue gas, or combustion gas, stream, and/or (iii) mercury speciation levels in the flue gas, or combustion gas, stream;
- (V) using the real-time data from Step (IV) to determine the amount of both of:
- (a) the one or more halogen-containing compounds that are injected in Step (II), and (b) the one or more sulfur-containing compounds and/or sulfide salt compounds that are injected in Step (III) into the at least one air quality control device.
A method for oxidizing and capturing elemental mercury present in a flue gas, or combustion gas, stream wherein the method comprises the steps of:
- (A) burning at least one fuel so as to yield a mercury-containing flue gas, or combustion gas, stream wherein at least a portion of the mercury in the mercury-containing flue gas, or combustion gas, stream is elemental mercury;
- (B) injecting one or more halogen-containing compounds into the mercury-containing flue gas, or combustion gas, stream in order to oxidize at least a portion of the elemental mercury in the mercury-containing flue gas, or combustion gas, stream into oxidized mercury and form one or more corresponding mercury halide compounds;
- (C) injecting one or more sulfur-containing compounds and/or sulfide salt compounds into at least one air quality control device in order to convert the one or more mercury halide compounds into one or more mercury-sulfur compounds that is, or are, insoluble in an aqueous environment or an aqueous-based environment;
- (D) capturing the one or more insoluble mercury-sulfur compounds in at least one air quality control device and/or downstream process equipment device;
- (E) supplying at least one control device and one or more real-time mercury sensing devices, or sensors, wherein the at least one control device is operatively connected to the one or more real-time mercury sensing devices, or sensors, in order to provide real-time data on at least two of:
- (i) oxidized mercury concentration level in the flue gas, or combustion gas, stream, (ii) elemental mercury concentration level in the flue gas, or combustion gas, stream, and/or (iii) mercury speciation levels in the flue gas, or combustion gas, stream;
- and
- (F) using the real-time data from Step (E) to determine the amount of both of:
- (a) the one or more halogen-containing compounds that are injected in Step (B), and (b) the one or more sulfur-containing compounds and/or sulfide salt compounds that are injected in Step (C) into the at least one air quality control device.
Dependencies are inferred from the claim text.