EP0385164B1
Expired / Lapsed
EP
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Catalyst for the selective reduction of nitric oxide with ammonia
Assignee: Evonik Operations GmbH
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Filing: 1990-02-12
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Granted: 1993-10-06
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Expires: 2010-02-12
Abstract
Abstract A catalyst for the selective reduction of nitrogen oxides by means of ammonia contains, in addition to titanium oxide as component A), at least one oxide selected from the group comprising W, Si, B, Al, P, Zr, Ba, Y, La and Ce and at least one oxide selected from the group comprising V, Nb, Mo, Fe and Cu as component B), the atomic ratio between the elements of the components A) and B) being 1 : 0.001 to 1. The catalyst is obtainable by kneading reactive titanium oxide of high specific surface area comprising predominantly anatase with the substances comprising component B) or their precursors with the addition of processing agents to give a homogeneous kneaded mass, extruding this, drying the extrudate and calcination in air at 300 - 800 DEG C.
Inventors
- 👤 Reinhold Dr. Brand
- 👤 Bernd H. Dr. Engler
- 👤 Wolfgang Dr. Honnen
- 👤 Edgar Dr. Koberstein
- 👤 Johannes Dr. Ohmer
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 06:45
CPC Classifications
B; B01; B01J; B01J21/00; B01J21/06; B01J21/066; B01J37/00; B01J37/0009; B01D; B01D53/00; B01D53/34; B01D53/74; B01D53/86; B01D53/8621; B01D53/8625; B01D53/8628; B01D53/92; B01D53/94; B01D53/9404; B01D53/9409; B01D53/9413; B01D53/9418; B01J21/063; B01J23/00; B01J35/00; B01J35/60; B01J35/61; B01J37/08; B01D2251/00; B01D2251/20; B01D2251/206; B01D2251/2062; B01D2255/00; B01D2255/20; B01D2255/207; B01D2255/20707; B01D2255/20723; B01D2255/20776; B01D2255/90; B01D2255/92; B01D2255/9207; B01J35/613; B01J35/615
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
199 words
A catalyst for the selective reduction of nitrogen oxides with ammonia containing the following components: A) titanium oxide B₁) at least one oxide of tungsten, silicon, boron, aluminium, phosphorus, zirconium, barium, yttrium, lanthanum, cerium and B₂) at least one oxide of vanadium, niobium, molybdenum, iron, copper, with an atomic ratio between the elements of components A) and B) of 1 : 0.001 to 1 and preferably 1 : 0.002 to 0.4, obtainable by intensively kneading component A) in the form of a reactive high-surface titanium oxide having a BET surface of 40 to 500, preferably 50 to 300 and more preferably 75 to 150 m²/g, which is completely or predominantly present in the anatase modification, together with components B₁) and B₂), preferably their precursors, with addition of the additives typically used for the compression moulding or extrusion of ceramic pastes, moistening agents, supporting substances, binders, moulding aids and, optionally, pore-forming agents, to form a homogeneous kneaded paste, extruding the kneaded paste to mouldings, drying the mouldings with a gradual increase in temperature to at most 60°C and then calcining them with a stepwise increase in temperature in ambient air at final temperatures in the range from 300 to 800°C.
Claim 2
Dependent Claim
30 words
A catalyst as claimed in claim 1, obtainable by using hydroxides, oxides, salts or heteropoly acids or salts thereof, preferably ammonium salts, as starting material for components B₁) and B₂).
Claim 3
Dependent Claim
65 words
A catalyst as claimed in claim 1 or 2, obtainable by mixing component A) and component B₁) in the kneader and subjecting the resulting mixture to dry preliminary kneading at pH 7 to 11 and preferably at pH 8 to 10 to a residual moisture content of 3 to 12% by weight and preferably from 5 to 10% by weight before component B₂) is added.
Claim 4
Dependent Claim
29 words
A catalyst as claimed in claim 3, obtainable by precalcining the dry-prekneaded mixture of components A) and B₁) at temperatures of 400 to 700°C before component B₂) is added.
Claim 5
Dependent Claim
40 words
A catalyst as claimed in claims 1 to 3, obtainable by precalcining the paste consisting of components A), B₁) and B₂) at 300 to 800°C and preferably at 400 to 700°C before it is kneaded to a homogeneous kneaded paste.
Claim 6
Dependent Claim
60 words
A catalyst as claimed in claims 1 to 5, characterized in that components B₁) and B₂) are used in the form of a heteropoly acid or one of its salts, preferably the ammonium salts, the metals of groups B₁) and B₂) present in the heteropoly acid being present in an atomic ratio of 12 : 1 to 1 : 12.
Claim 7
Dependent Claim
62 words
A catalyst as claimed in claim 1 or 2, obtainable by leaving the starting material for component B₂) out of the kneading process and applying it by impregnation in the form of a salt or a heteropoly acid or one of its salts, preferably the ammonium salts, in aqueous solution to the preferably calcined catalyst precursor consisting of components A) and B₁).
Claim 8
Dependent Claim
212 words
A process for the production of a catalyst for the selective reduction of nitrogen oxides with ammonia containing the following components: A) titanium oxide B₁) at least one oxide of tungsten, silicon, boron, aluminium, phosphorus, zirconium, barium, yttrium, lanthanum, cerium and B₂) at least one oxide of vanadium, niobium, molybdenum, iron, copper, with an atomic ratio between the elements of components A) and B) of 1 : 0.001 to 1 and preferably 1 : 0.002 to 0.4, characterized in that it comprises the steps of intensively kneading kneading component A) in the form of a reactive high-surface titanium oxide having a BET surface of 40 to 500, preferably 50 to 300 and more preferably 75 to 150 m²/g, which is completely or predominantly present in the anatase modification, together with components B₁) and B₂), preferably their precursors, with addition of the additives typically used for the compression moulding or extrusion of ceramic pastes, moistening agents, supporting substances, binders, moulding aids and, optionally, pore-forming agents, to form a homogeneous kneaded paste, extruding the kneaded paste to mouldings, drying the mouldings with a gradual increase in temperature to at most 60°C and then calcining them with a stepwise increase in temperature in ambient air at final temperatures in the range from 300 to 800°C.
Claim 9
Dependent Claim
32 words
A process as claimed in claim 8, characterized in that hydroxides, oxides, salts or heteropoly acids or salts thereof, preferably ammonium salts, are used as starting material for components B₁) and B₂).
Claim 10
Dependent Claim
67 words
A process as claimed in claim 8 or 9, characterized in that component A) and component B₁) are mixed in the kneader and the resulting mixture is subjected to dry preliminary kneading at pH 7 to 11 and preferably at pH 8 to 10 to a residual moisture content of 3 to 12% by weight and preferably 5 to 10% by weight before component B₂) is added.
Claim 11
Dependent Claim
31 words
A process as claimed in claim 10, characterized in that the dry-prekneaded mixture of components A) and B₁) is precalcined at temperatures of 400 to 700°C before component B₂) is added.
Claim 12
Dependent Claim
42 words
A process as claimed in claims 8 to 10, characterized in that the paste consisting of components A), B₁) and B₂) is precalcined at 300 to 800°C and preferably at 400 to 700°C before it is kneaded to a homogeneous kneaded paste.
Claim 13
Dependent Claim
60 words
A process as claimed in claims 8 to 12, characterized in that components B₁) and B₂) are used in the form of a heteropoly acid or one of its salts, preferably the ammonium salts, the metals of groups B₁) and B₂) present in the heteropoly acid being present in an atomic ratio of 12 : 1 to 1 : 12.
Claim 14
Dependent Claim
63 words
A process as claimed in claim 8 or 9, characterized in that the starting material for component B₂) is left out of the kneading process and applied by impregnation in the form of a salt or a heteropoly acid or one of its salts, preferably the ammonium salts, in aqueous solution to the preferably calcined catalyst precursor consisting of components A) and B₁).
References Cited (Backward Citations)
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