Catalyst for removing nitrogen oxides and a process for producing the same
First Claim
1. A catalyst for removing nitrogen oxides comprising a catalyst composition containing titanium oxide and at least one member of oxides of vanadium, molybdenum and tungsten, and inorganic fibers, wherein the clearances of the inorganic fibers are filled with said catalyst composition;
- the ratio by weight of said catalyst composition to said inorganic fibers is 3 or more; and
the apparent density of said catalyst is 0.8g/cm3 or more.
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Abstract
A catalyst or a catalyst structure for removing nitrogen oxides contained in exhaust gases, having a small pressure loss and hard to cause ash deposition, and a process for producing the same are provided, which catalyst comprises a mixture of a catalyst composition of titanium oxide and at least one member of oxides of vanadium, molybdenum and tungsten, and inorganic fibers, the clearances of the inorganic fibers are filled with said catalyst composition; the ration by weight of said catalyst composition to said inorganic fibers is 3 or more; and the apparent density of said catalyst is 0.8 g/cm3 or more; and which process comprises providing a composition containing titanium oxide and at least one member of oxides of vanadium, molybdenum and tungsten, calcining said composition at 500°-650° C., crushing the calcined material so that powder of 20μ or less can occupy 90% by weight or more of the crushed material, adding water to the crushed material to form a slurry, impregnating an inorganic fiber sheet with the above slurry, placing the resulting sheet between porous molds, drying and molding it, and clacining the resulting molded material at 300°-650° C.
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Citations
10 Claims
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1. A catalyst for removing nitrogen oxides comprising a catalyst composition containing titanium oxide and at least one member of oxides of vanadium, molybdenum and tungsten, and inorganic fibers, wherein the clearances of the inorganic fibers are filled with said catalyst composition;
- the ratio by weight of said catalyst composition to said inorganic fibers is 3 or more; and
the apparent density of said catalyst is 0.8g/cm3 or more.
- the ratio by weight of said catalyst composition to said inorganic fibers is 3 or more; and
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2. A process for producing a catalyst for removing nitrogen oxides, which comprises providing a composition containing titanium oxide and at least one member of oxides of vanadium, molybdenum and tungsten, calcining said composition at 500-650°
- C., crushing the calcined material so that powder of 20μ
or less can occupy 90% by weight or more of the crushed material, adding water to the crushed material to form a slurry, impregnating an inorganic fiber sheet with said slurry, placing the resulting sheet between porous molds, drying and molding it, and calcining the resulting molded material at 300-650°
C. to obtain a molded catalyst. - View Dependent Claims (3, 4, 5, 6)
- C., crushing the calcined material so that powder of 20μ
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7. A process for producing a catalyst assembly for removing nitrogen oxides, which comprises providing a composition containing titanium oxide and at least one member of oxides of vanadium, molybdenum and tungsten, calcining said composition at 500-650°
- C., crushing the calcined material so that powder of 20μ
or less can occupy 90% by weight or more of the crushed material, adding water to the crushed material to form a catalyst slurry, providing an inorganic fiber sheet as a substrate, impregnating said sheet with said slurry, placing said impregnated sheet between porous molds, drying and molding it, calcining the resulting molded material at 300-650°
C. to obtain a molded catalyst, piling said molded catalyst and an inorganic fiber sheet impregnated with a catalyst slurry prepared in the same manner as the above, alternately, drying and calcining to form a catalyst assembly. - View Dependent Claims (8)
- C., crushing the calcined material so that powder of 20μ
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9. A process for producing a catalyst for removing nitrogen oxides, which comprises providing a composition containing titanium oxide and at least one member of oxides of vanadium, molybdenum and tungsten, calcining said composition at 500-650°
- C., crushing the calcined material so that powder of 20μ
or less can occupy 90% by weight or more of the crushed material, adding water and an inorganic fiber to the crushed material to form a paste, coating an inorganic fiber sheet with said paste, placing the resulting sheet between porous molds, drying and molding it, and calcining the resulting molded material at 300-650°
C. to obtain a molded catalyst. - View Dependent Claims (10)
- C., crushing the calcined material so that powder of 20μ
Specification