Chromium particulate emissions in flue gas can be reduced or minimized by incorporating a thin layer bed of a catalyst within the flue gas flow path of a furnace, boiler, or other furnace environment that includes Cr-containing surfaces. The thin layer bed of catalyst can correspond to, for example, a honeycomb monolith with catalyst supported on the monolith surface, so as to provide a high contact area while forcing all of the flue gas to pass through the catalyst bed. The honeycomb monolith structure and the depth of the bed can be selected to provide a reduced or minimized pressure drop across the catalyst bed, such as a pressure drop of 0.25 kPa (1.0 inches of water) or less. Exposing the Cr-containing flue gas to the thin layer catalyst bed can result in a treated flue gas with a lower content of Cr.

A multi-functional composition of matter that is useful for injection into a flue gas stream to rapidly and efficiently remove mercury from the flue gas streams, particularly at above average flue stream temperatures of about 340° F. or higher. The multi-functional composition of matter may include a fixed carbon content of at least about 20 wt. %, a mineral content of from about 20 wt. % to about 50 wt. %, a sum of micropore plus mesopore volume of at least about 0.20 cc/g, a micropore volume to mesopore volume ratio of at least about 0.7, and a tapped density of not greater than about 0.575 g/ml. These compositions may be further characterized by number of particles per gram of the composition of matter such that the composition may have at least about 0.8 billion particles per gram, or even as many as 1.5 billion particles per gram. These physical and chemical properties may enhance (1) the oxidation reaction kinetics for the oxidation of mercury species, (2) frequency of contact events, and (3) capture and sequestration of mercury, to achieve efficient mercury capture by the composition even in high temperature flue gas streams.

The invention relates to an intelligent multi-pollutant ultra-low emission system and a global optimization method thereof. The intelligent multi-pollutant ultra-low emission system comprises a device layer, a sensing layer, a control layer and an optimization layer from bottom to top. The global optimization method comprises: obtaining an accurate description multiple pollutants in the generation, migration, transformation and removal process in multiple devices by means of accurate modeling of a multi-device multi-pollutant simultaneous removal process of the ultra-low emission system; accurately evaluating multi-pollutant emission reduction costs under different loads, coal qualities, pollutant concentrations and operating parameters through a global operating cost evaluation method of the ultra-low emission system; realizing minute-level planning and optimization of emission reductions of a global pollutant emission reduction device under different emission targets through a multi-pollutant, multi-target and multi-condition global operating optimization method; and guaranteeing reliable emission reduction and margin control of the pollutants through an advanced control method for reliable up-to-standard ultra-low emission of the pollutants.

A sorbent composition that is useful for injection into a flue gas stream of a coal burning furnace to efficiently remove mercury from the flue gas stream. The sorbent composition may include a sorbent with an associated ancillary catalyst component that is a catalytic metal, a precursor to a catalytic metal, a catalytic metal compound or a precursor to a catalytic metal compound. Alternatively, a catalytic metal or metal compound, or their precursors, may be admixed with the coal feedstock prior to or during combustion in the furnace, or may be independently injected into a flue gas stream. A catalytic promoter may also be used to enhance the performance of the catalytic metal or metal compound.

The present invention refers to a method for the preparation of a shell type catalyst for mercury oxidation, the catalyst and the use of the catalyst. The catalyst is prepared by a method comprising mixing titanium dioxide, a compound of a promoter selected from molybdenum and tungsten, and a binder, to prepare a paste; shaping the paste, to obtain a shaped paste; drying and optionally calcining the shaped paste, to obtain a support material; impregnating the support material with an aqueous alkaline impregnation solution comprising a vanadium compound; drying and calcining the impregnated support material, to obtain the catalyst. The catalyst is useful for purifying exhaust gases from coal plants and other power plants where mercury emissions occurs.

The present disclose is directed to a method for controlling iodine levels in wet scrubbers, and, in particular, recirculating wet scrubbers by removing the iodine from the scrubbing solution, such as by using ion exchange, absorption, adsorption, precipitation, filtration, solvent extraction, ion pair extraction, and an aqueous two-phase extraction.

The present invention relates to activated carbon sorbents including nitrogen. In various embodiments, the present invention provides an activated carbon sorbent including a halogen- or halide-promoted activated carbon, the activated carbon sorbent particles including nitrogen in a surface layer of the sorbent particles. In various embodiments, the present invention provides a method of reducing the pollutant content in a pollutant-containing gas using the activated carbon sorbent. In various embodiments, the activated carbon sorbent can remove mercury from a mercury-containing gas that includes sulfur(VI) such as SO.sub.3 more efficiently than other sorbents.

A sorbent composition that is useful for injection into a flue gas stream of a coal burning furnace to efficiently remove mercury from the flue gas stream. The sorbent composition may include a sorbent with an associated ancillary catalyst component that is a catalytic metal, a precursor to a catalytic metal, a catalytic metal compound or a precursor to a catalytic metal compound. Alternatively, a catalytic metal or metal compound, or their precursors, may be admixed with the coal feedstock prior to or during combustion in the furnace, or may be independently injected into a flue gas stream. A catalytic promoter may also be used to enhance the performance of the catalytic metal or metal compound.

A sorbent composition that is useful for injection into a flue gas stream of a coal burning furnace to efficiently remove mercury from the flue gas stream. The sorbent composition may include a sorbent with an associated ancillary catalyst component that is a catalytic metal, a precursor to a catalytic metal, a catalytic metal compound or a precursor to a catalytic metal compound. Alternatively, a catalytic metal or metal compound, or their precursors, may be admixed with the coal feedstock prior to or during combustion in the furnace, or may be independently injected into a flue gas stream. A catalytic promoter may also be used to enhance the performance of the catalytic metal or metal compound.

A magnetic adsorbent, including an admixture of an adsorbent and a magnetic material. A system for removing mercury from a fluid stream, the system including, a magnetic adsorbent injection unit for injecting an admixture of powdered activated carbon and magnetic material into the fluid stream; and a particulate removal unit. Also included are methods for removing mercury from a fluid stream and methods for producing a magnetic sorbent.