Abstract: A catalyst for nitrogen oxide removal, which catalytically reduces nitrogen oxides in an exhaust gas in the presence of ammonia, comprises: a first component comprising an oxide of titanium, an oxide of tungsten, and an oxide of vanadium; and a second component comprising an oxide of manganese, or an oxide of manganese and an oxide of copper.

Abstract: A high temperature denitration catalyst of a gas turbine single plant contains TiO2, at least one of WO3 and MoO3 and V2O5 of 0.5 wt % or less, preferably 0.2 wt % or less, or none of V2O5, and is optimized to be used in a temperature range up to a maximum 450 to 600° C. The used high temperature denitration catalyst is immersed into a V-containing water solution and dried and/or burned. An intermediate temperature denitration catalyst is produced containing a V2O5 component of 0.5 wt % or more, preferably 1.0 wt % or more, and is optimized for use in a temperature range of 250 to 450° C. This intermediate temperature denitration catalyst is re-used in a combined cycle plant after being modified or in other plants.

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: An object of the present invention is to provide a catalyst for treating exhaust gas adapted not only to remove CO and VOCs based on unsaturated hydrocarbons such as C2H4 but also to accelerate a decomposition reaction of saturated hydrocarbons such as propane and to provide a method for producing such a catalyst for treating exhaust gas. The present invention provides a catalyst for treating an exhaust gas containing carbon monoxide and volatile organic compounds, the catalyst comprising a substrate containing a NOx removal catalyst component and a porous inorganic compound layer containing a noble metal, the layer being applied to the substrate.

Abstract: Provided are a flue gas denitration catalyst having high denitration activity and capable of suppressing a side reaction, that is, oxidation of SO2; and a preparation process of the catalyst. The flue gas denitration catalyst comprises TiO2, WO3 and V2O5. In the surface layer of the catalyst within 200 ?m from the surface thereof, V2O5 is supported on a carrier containing TiO2 and WO3. The supported amounts of V2O5 range from 0.4 to 5 wt. % based on the weight of the surface layer and range from 0.1 to 0.9 wt. % based on the total weight of the catalyst. The V2O5 thus supported has a crystallite size of less than 10 nm as measured by X-ray diffraction. The catalyst can be available by preparing a mixture containing TiO2 and WO3 and having V2O5 supported on the surface of an extruded product of the prepared mixture by a vapor phase method.

Abstract: The invention provides a discharge gas treatment apparatus and method which prevent increase in treatment cost and which attain efficient removal of mercury contained in a discharge gas.

Abstract: A catalyst for purifying an exhaust gas containing carbon monoxide and volatile organic compounds, which has a coat layer of a carrier composed of a porous inorganic compound, wherein the coat layer is a single layer, the porous inorganic compound has a BET specific surface area of 50 m2/g or greater, and the coat layer has, within a 50 ?m depth from the surface thereof, an active metal having a particle size of 15 nm or less and composed of at least one noble metal.

Abstract: The invention provides a discharge gas treatment catalyst which can effectively decreases NOx and SO3 contained in a discharge gas. The discharge gas treatment catalyst, for removing nitrogen oxide and sulfur trioxide from a discharge gas, includes a carrier which is formed of titania-tungsten oxide and which carries ruthenium, and a titania-tungsten oxide-based NOx removal catalyst serving as a substrate which is coated with the carrier. When a discharge gas to which ammonia has been added and which contains SO3 and NOx is brought into contact with the catalyst, decomposition of ammonia is suppressed by ruthenium, and reduction of SO3 and NOx contained in the discharge gas is promoted, whereby SO3 concentration and NOx concentration can be further decreased.

Abstract: A denitrification catalyst regeneration method comprises heat-treating a used denitrification catalyst, then cleaning the denitrification catalyst with an aqueous solution of oxalic acid, and then finish washing the denitrification catalyst with water to regenerate the denitrification catalyst.

Abstract: The present invention is to provide a catalyst for removing nitrogen oxides which is capable of keeping sufficient denitrification performance, i.e., a high removal rate of nitrogen oxides in exhaust gas having a high NO2 content especially under conditions where the ratio of NO2/NO in exhaust gas is 1 or higher, a catalyst molded product therefor, and an exhaust gas treating method. The catalyst is designed for removing nitrogen oxides, which is used to denitrify exhaust gas containing nitrogen oxides having a high NO2 content, which comprises: at least one kind of oxide selected from the group consisting of copper oxides, chromium oxides, and iron oxides as a component for reducing NO2 to NO; and which further comprises: at least one kind of titanium oxide; at least one kind of tungsten oxide; and at least one kind of vanadium oxide as components for reducing NO to N2.

Abstract: Provided are a flue gas denitration catalyst having high denitration activity and capable of suppressing a side reaction, that is, oxidation of SO2; and a preparation process of the catalyst. The flue gas denitration catalyst comprises TiO2, WO3 and V2O5. In the surface layer of the catalyst within 200 ?m from the surface thereof, V2O5 is supported on a carrier containing TiO2 and WO3. The supported amounts of V2O5 range from 0.4 to 5 wt. % based on the weight of the surface layer and range from 0.1 to 0.9 wt. % based on the total weight of the catalyst. The V2O5 thus supported has a crystallite size of less than 10 nm as measured by X-ray diffraction. The catalyst can be available by preparing a mixture containing TiO2 and WO3 and having V2O5 supported on the surface of an extruded product of the prepared mixture by a vapor phase method.

Abstract: Provided are a flue gas denitration catalyst having high denitration activity and capable of suppressing a side reaction, that is, oxidation of SO2; and a preparation process of the catalyst. The flue gas denitration catalyst comprises TiO2, WO3 and V2O5. In the surface layer of the catalyst within 200 &mgr;m from the surface thereof, V2O5 is supported on a carrier containing TiO2 and WO3. The supported amounts of V2O5 range from 0.4 to 5 wt. % based on the weight of the surface layer and range from 0.1 to 0.9 wt. % based on the total weight of the catalyst. The V2O5 thus supported has a crystallite size of less than 10 nm as measured by X-ray diffraction. The catalyst can be available by preparing a mixture containing TiO2 and WO3 and having V2O5 supported on the surface of an extruded product of the prepared mixture by a vapor phase method.

Abstract: A method for economically modifying a gas turbine single plant into a combined cycle plant, a method for re-using a used high temperature denitration catalyst of the gas turbine single plant as an intermediate temperature denitration catalyst of other modified, existing or new plants and a re-produced catalyst are provided. The high temperature denitration catalyst of the gas turbine single plant contains TiO2, at least one of WO3 and MoO3 and V2O5 of 0.5 wt % or less, preferably 0.2 wt % or less or none of V2O5 and is optimized to be used in the temperature range up to maximum 450 to 600° C. The used high temperature denitration catalyst is immersed into V-containing water solution and dried and/or burned. An intermediate temperature denitration catalyst is re-produced containing V2O5 component of 0.5 wt % or more, preferably 1.0 wt % or more, and being optimized to be used in the temperature range of 250 to 450° C.

Abstract: The present invention provides a method of denitrating exhaust gas, which can control the NOx removal efficiency of exhaust gas at 90% or higher while suppressing the release of unreacted ammonia to 0.1 ppm or less. The method carries out denitration of exhaust gas for removing nitrogen oxides with catalytic reduction by introducing a nitrogen-oxide-containing gas into a catalyst-filled reaction chamber and adding ammonia as reducing agent in an excessive amount to the same chamber.

Abstract: This invention provides a method for the regeneration of a denitration catalyst which comprises cleaning a denitration catalyst having reduced denitration power with an aqueous alkaline solution to remove the substances deposited thereon, and subjecting the catalyst to an activation treatment with an aqueous acid solution; a method for the regeneration of a denitration catalyst which comprises cleaning a denitration catalyst having reduced denitration power with a cleaning fluid comprising an aqueous solution containing sulfuric acid or ammonia at a concentration of 0.05 to 20% by weight and maintained at a temperature of 10 to 90°C.; and a method for the regeneration of a denitration catalyst which comprises cleaning a denitration catalyst having reduced denitration power under the above-described conditions, and impregnating the denitration catalyst with a catalytically active component so as to support it on the catalyst.

Abstract: There are provided a honeycomb catalyst in which irregularities are formed on a catalyst inside wall in a honeycomb hole, and a manufacturing method for a honeycomb catalyst by using an extrusion molding method, in which extrusion molding is effected by using a mold having a means for providing irregularities to a catalyst inside wall of a honeycomb hole.

Abstract: A method of denitrating an exhaust gas by means of removing nitrogen oxides catalytically using ammonia as a reducing agent while introducing an exhaust gas containing the nitrogen oxides into a reaction vessel packed with a catalyst, comprising:providing a denitration catalyst layer in the upstream of the gas flow, an ammonia decomposition catalyst layer capable of decomposing oxidatively ammonia into nitrogen and nitrogen oxides in the downstream and a second denitration catalyst layer or a denitration catalyst layer capable of decomposing ammonia in the further downstream; and,adding ammonia in an amount not less than the reaction equivalence for the nitrogen oxides in the exhaust gas to the inlet of the first denitration catalyst layer.

Abstract: Disclosed are (1) a method for the regeneration of a denitration catalyst wherein, in order to regenerate a denitration catalyst having reduced denitration power, the catalyst is cleaned with a cleaning fluid having a hydrofluoric acid concentration of 0.3 to 3% by weight and maintained at a temperature of 20 to 80.degree. C., and (2) a method for the regeneration of a denitration catalyst which comprises the steps of cleaning a denitration catalyst having reduced denitration power under the conditions described in (1) above, drying the cleaned catalyst, and impregnating the catalyst with a catalytically active component so as to support it on the catalyst.

Abstract: The present invention relates to a method for removing clogging dust in gas passing holes in a honeycomb catalyst. A honeycomb catalyst whose gas passing holes are clogged with dust in exhaust gas is immersed in water in a vessel, and then the vessel is closed and vacuum suction is exerted, by which water is allowed to flow in the gas passing holes in the honeycomb catalyst to remove dust in the gas passing holes.

Abstract: This invention effectively utilizes a solid type honeycomb-shaped NO.sub.x removal catalyst which has been used in a catalytic ammonia reduction process and hence reduced in NO.sub.x removal power, and thereby provides an inexpensive catalyst having NO.sub.x removal power equal to that of a fresh catalyst. The nitrogen oxide removal catalyst of this invention, which is useful in a process wherein ammonia is added to exhaust gas and nitrogen oxides present in the exhaust gas are catalytically reduced, has a two-layer structure composed of a lower layer comprising a spent solid type nitrogen oxide removal catalyst and an upper layer comprising a fresh TiO.sub.2 -WO.sub.3 -V.sub.2 O.sub.5 ternary or TiO.sub.2 -WO.sub.3 binary catalyst powder which has been applied to the lower layer so as to give a coating thickness of 100 to 250 .mu.m. Moreover, the catalyst power constituting the upper layer is a catalyst powder obtained by pulverizing a spent solid type nitrogen oxide removal catalyst.