Abstract: In a NOx removal catalyst used for removing nitrogen oxide in flue gas, when a silica (Si) component as an inhibitor that causes an increase in an SO2 oxidation rate accumulates on a surface of the NOx removal catalyst, the silica component accumulating on the surface of the NOx removal catalyst is dissolved, thereby regenerating the catalyst. Accordingly, the inhibitor such as the silica component covering the surface of the NOx removal catalyst can be removed, thereby enabling to provide a catalyst without having an increase in the SO2 oxidation rate of the regenerated NOx removal catalyst.

Abstract: The method includes a pretreatment step during an operation of a boiler in which in a predetermined period of time before shutdown of the boiler, a part of combustion gas that has bypassed an economizer provided in a flue gas duct for flue gas from the boiler is supplied to an upstream of a NOx removal device having a NOx removal catalyst and mixed with the combustion flue gas from the economizer to generate mixed gas having a predetermined temperature equal to or higher than 360° C. (360° C. to 450° C.), the mixed gas is introduced into the NOx removal catalyst, thereby decomposing VOSO4 adhering to and accumulating on the NOx removal catalyst into V2O5.

Abstract: A highly durable mercury oxidation catalyst contains V2O5 and MoO3 as active components, and is capable of preventing volatilization of MoO3 in the mercury oxidation catalyst. A method of producing the mercury oxidation catalyst is provided. A mercury oxidation catalyst oxidizing mercury in an exhaust gas into mercury oxide includes: TiO2 as a carrier, V2O5 and MoO3 supported on the carrier as active components, and at least one kind of element or compound selected from the group consisting of W, Cu, Co, Ni, and Zn or the compounds thereof supported on the carrier as a MoO3 volatilization preventing component.

Abstract: In the catalyst for purifying a combustion exhaust gas containing nitrogen oxides, 50 wt. % or greater of the amount of Ru and/or Ir to be supported is adjusted to fall within a depth of 150 ?m from the surface layer of a substrate; and the catalyst is prepared by immersing the substrate in a metal colloid solution of Ru and/or Ir to be supported or an aqueous solution containing at least one compound selected from compounds of Ru and/or Ir to be supported.

Abstract: To provide a catalyst for treating exhaust gases containing nitrogen monoxide, carbon monoxide and volatile organic compounds whose oxidation power has been enhanced without increasing the amount of precious metal supported thereon; a method for producing the same; and a method for treating exhaust gases. A catalyst for treating exhaust gases, including coat layers made up of a plurality of layers, an upper layer of which has an active component contained uniformly therein and a lower layer of which has no active component contained therein, can be obtained through the steps of: forming the lower layer by coating the surface of substrate with a slurry of a porous inorganic compound, followed by drying; and forming the upper layer, which is to be the top surface of the catalyst, by coating the surface of the lower layer with a slurry of a porous inorganic compound that has the active component composed of one or more precious metals supported thereon, followed by drying.

Abstract: A catalyst for treating exhaust gases containing nitrogen monoxide, carbon monoxide and volatile organic compounds includes a plurality of layers, an upper layer of which has an active component contained uniformly therein and a lower layer of which has no active component contained therein. The catalyst is obtained through the steps of: forming the lower layer by coating the surface of substrate with a slurry of a porous inorganic compound, followed by drying; and forming the upper layer, which is to be the top surface of the catalyst, by coating the surface of the lower layer with a slurry of a porous inorganic compound that has the active component composed of one or more precious metals supported thereon, followed by drying. The oxidation power of the resulting catalyst is enhanced without increasing the amount of precious metal supported thereon.

Abstract: Provided are an exhaust gas treatment catalyst capable of reducing ammonia leakage rate while keeping a sufficient NOx removal efficiency, said catalyst comprising a coating layer and a catalyst base material, wherein said coating layer has a decreased thickness relative to that of a catalyst base material; and an exhaust gas treatment system using the same. In the exhaust gas treatment catalyst for catalytically removing nitrogen oxides from an exhaust gas by using ammonia as a reducing agent and simultaneously decomposing and removing unreacted ammonia, a coating layer comprising platinum supported on titania is formed on a surface of a porous catalyst base material comprising titania and at least one compound selected from oxides of vanadium (V), oxides of tungsten (W) and oxides of molybdenum (Mo).

Abstract: It is intended to provide an exhaust gas treatment system, which allows for VOC removal at lower temperatures and thereby improves the durability of catalysts and suppresses carbon monoxide generation at the final outlet of the system. The present invention provides a treatment system of an exhaust gas containing a nitrogen oxide, carbon monoxide, and a volatile organic compound comprising: an exhaust gas treatment means for removing the nitrogen oxide by reduction with ammonia and partially oxidizing the VOC to CO; and a CO/VOC removal means for oxidizing the CO and partially unreacted VOC, in this order from the upstream flow of the exhaust gas.

Abstract: It is intended to provide an exhaust gas treatment system, which allows for VOC removal at lower temperatures and thereby improves the durability of catalysts and suppresses carbon monoxide generation at the final outlet of the system. The present invention provides a treatment system of an exhaust gas containing a nitrogen oxide, carbon monoxide, and a volatile organic compound comprising: an exhaust gas treatment means for removing the nitrogen oxide by reduction with ammonia and partially oxidizing the VOC to CO; and a CO/VOC removal means for oxidizing the CO and partially unreacted VOC, in this order from the upstream flow of the exhaust gas.

Abstract: A NOx removal catalyst for high-temperature flue gas according to the present invention is a NOx removal catalyst for high-temperature flue gas that contains nitrogen oxide in which tungsten oxide with the number of molecular layers of tungsten oxide (WO3) being five or less is supported on a complex oxide carrier containing titanium oxide. Even when high-temperature denitration is continued, a bonding force with a carrier of WO3 can be properly maintained and volatilization can be suppressed while maintaining a high NOx removal performance. For example, the NOx removal catalyst is particularly suitable for reducing and removing nitrogen oxide contained in high-temperature gas discharged from a thermal power plant and a high-temperature boiler.

Abstract: In an exhaust gas treatment, the amount of a highly corrosive mercury-halogenating agent to be added is reduced with the mercury-removing efficiency maintained high. A mercury-halogenating agent (40) and ammonia (30) are added to combustion exhaust gas from a boiler, the exhaust gas containing NOx, SOx and mercury. The exhaust gas is brought into contact with a CO/HC oxidation catalyst (50) and is then subjected to reduction denitration (60) in the presence of a solid catalyst. Thereafter, metallic mercury is oxidized to halogenated mercury. Then, the exhaust gas is wet-desulfurized (100) with the alkaline absorbing solution, and the halogenated mercury is removed.

Abstract: An air pollution control apparatus includes at least one denitration catalyst layer for reducing the amounts of nitrogen oxides in flue gas from a boiler and oxidizing mercury with hydrogen chloride sprayed into the flue gas. Spraying pipe headers 51 are disposed in a flue gas duct 19. The spraying pipe headers 51 are inserted into the flue gas duct 19 and arranged in a direction orthogonal to the direction of a gas flow in the flue gas duct 19. At least four spray nozzles 52-1 to 52-4 are disposed on the spraying pipe header 51 to form a vertical vortex flow 53 in the gas flow direction. The diffusion of hydrogen chloride is thereby facilitated in a rapid manner. Therefore, the number of the nozzles can be reduced, and the uniformity of the concentration of hydrogen chloride at the location of the catalyst can be ensured even when the spacing between the nozzles is increased.

Abstract: An air pollution control apparatus 10 according to an embodiment of the present invention has a denitration catalyst layer 13 that removes nitrogen oxides in flue gas, and atomizes hydrochloric acid into flue gas to oxidize mercury, and also includes a swirling-flow generating member 15A including a vertical axis 22 provided in a passage 14 of a honeycomb catalyst, and four swirling-flow generating vanes 23 provided radially with respect to the vertical axis 22 for generating a turbulent flow in flue gas, with the swirling-flow generating vanes 23 being arranged in a direction of the vertical axis 22 with a predetermined gap therebetween. With this configuration, by generating a swirling flow in flue gas in the passage 14 in the denitration catalyst layer 13, a contact time between flue gas and a denitration catalyst can be increased, and the oxidation reaction efficiency between mercury in flue gas and the denitration catalyst can be improved.

Abstract: An air pollution control apparatus 10 according to an embodiment of the present invention has a denitration catalyst layer 13 that removes NOx in flue gas 12, and atomizes HCl into the flue gas 12 to oxidize Hg, and also includes a swirling-flow generating member 30A that includes a swirling-flow generating-member body being partitioned to correspond to each passage of the denitration catalyst layer 13 and a plurality of swirling-flow generating vanes arranged on the partition inner walls to generate a turbulent flow, on an inlet 13a side of the denitration catalyst layer 13. With this configuration, a laminar flow of the flue gas 12 in a flue gas duct 19 is changed to a swirling flow, thereby enabling to increase a contact time between the flue gas 12 and a denitration catalyst and to improve the oxidation reaction efficiency between Hg in the flue gas 12 and the denitration catalyst.

Abstract: An exhaust gas treating apparatus removes nitrogen oxides and mercury in exhaust gas from a boiler using an ammonia denitration catalyst, including: an ammonium chloride powder feed unit for feeding ammonium chloride, in powder form, into a vicinity of an entrance of an economizer provided to a combustion gas flue of the boiler and/or an economizer bypass unit, the fed ammonium chloride in powder form being sublimed by a combustion gas, to thereby feed hydrogen chloride and ammonia into the flue; and an ammonium chloride liquid feed unit for feeding ammonium chloride, in liquid form, into a vicinity of the entrance of the economizer and/or the economizer bypass unit, the ammonium chloride liquid feed unit also being capable of feeding ammonium chloride, vaporization of the fed ammonium chloride in liquid form by the combustion gas also allowing hydrogen chloride and ammonia to be fed into the flue.

Abstract: A highly durable mercury oxidation catalyst contains V2O5 and MoO3 as active components, and is capable of preventing volatilization of MoO3 in the mercury oxidation catalyst. A method of producing the mercury oxidation catalyst is provided. A mercury oxidation catalyst oxidizing mercury in an exhaust gas into mercury oxide includes: TiO2 as a carrier, V2O5 and MoO3 supported on the carrier as active components, and at least one kind of element or compound selected from the group consisting of W, Cu, Co, Ni, and Zn or the compounds thereof supported on the carrier as a MoO3 volatilization preventing component.

Abstract: An air pollution control apparatus according to the present invention reduces nitrogen oxides and oxidizes mercury in flue gas 16 discharged from a boiler by an ammonia denitrating catalyst. The air pollution control apparatus includes an economizer bypassing unit 15a that diverts high-temperature combustion gas 11 to a downstream side while bypassing an economizer 15 provided in a gas flue 10a for combustion gas 11 from the boiler, provided with an ammonium-chloride supply unit 101 that supplies powdery ammonium chloride (NH4Cl) to the economizer bypassing unit 15a. The air pollution control apparatus sublimates the ammonium chloride in an atmosphere at a high temperature of the combustion gas 11, and supplies hydrogen chloride and ammonium into the flue gas flue 102.

Abstract: Provided is a catalyst for treating exhaust gas capable of reducing the amount of a highly corrosive mercury-chlorinating agent to be added while keeping the mercury oxidation efficiency high in an exhaust gas treatment. By the catalyst for treating exhaust gas, nitrogen oxide in the exhaust gas is removed upon contact with ammonia serving as a reducing agent, and mercury is oxidized using a halogen serving as an oxidant. The catalyst includes: TiO2 as a support; an oxide of at least one selected from the group consisting of V, W and Mo, which is supported as an active component on the support; and at least one selected from the group consisting of Bi, P, and compounds containing Bi and/or P, which is supported as a co-catalyst component on the support.

Abstract: An exhaust gas treatment catalyst for removal of one or more pollutants in an exhaust gas, the catalyst comprising: a SO3-reducing catalyst powder which removes the above-described pollutants; and a diluent powder which is not the SO3-reducing catalyst powder nor a catalyst for reactions between exhaust gas components and a reagent, wherein the SO3-reducing catalyst powder is dispersed in the diluent powder.

Abstract: An exhaust gas treating apparatus removes nitrogen oxides and mercury in an exhaust gas from a boiler by use of an ammonia denitration catalyst, the exhaust gas treating apparatus including: an ammonium chloride powder feed unit 101 for feeding ammonium chloride, in powder form, into any one of or both of a vicinity of an entrance of an economizer 15 provided to a combustion gas flue of the boiler and an economizer bypass unit 15a, the fed ammonium chloride in powder form being sublimed by a combustion gas, to thereby feed hydrogen chloride and ammonia into the flue 102; and an ammonium chloride liquid feed unit 110 for feeding ammonium chloride, in liquid form, into any one of or both of a vicinity of the entrance of the economizer 15 and the economizer bypass unit 15a, the ammonium chloride liquid feed unit 110 also being capable of feeding ammonium chloride, vaporization of the fed ammonium chloride in liquid form by the combustion gas also allowing hydrogen chloride and ammonia to be fed into the flue 102