EP0661089A2
Expired / Lapsed
EP
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Device and method for cleaning exhaust gas
Assignee: Riken Corp
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Filing: 1994-12-22
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Granted: —
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Expires: 2014-12-22
Abstract
Abstract An exhaust gas cleaner constituted by a first catalyst comprising a first porous inorganic oxide supporting an Ag component alone or in combination with a Pt component or a W component and a second catalyst comprising a second porous inorganic oxide supporting a Pt component and optionally a W component, at least one of the first and second catalysts containing the W component. The Ag component may include Ag and compounds thereof, the Pt component of the first and second catalysts may include Pt, Pd, Ru, Rh, Ir and Au, and the W component of the first and second catalysts may include W, V, Mn, Mo, Nb and Ta. The W component effectively catalyze the reduction of nitrogen oxides by ammonia to enhance the removal efficiency of the exhaust gas cleaner.
Inventors
- 👤 Akira C/O Kabushiki Kaisha Riken Abe
- 👤 Kiyohide C/O Kabushiki Kaisha Riken Yoshida
- 👤 Gyo C/O Kabushiki Kaisha Riken Muramatsu
- 👤 Satoshi C/O Kabushiki Kaisha Riken Sumiya
- 👤 Naoko C/O Kabushiki Kaisha Riken Irite
- 👤 Mika C/O Kabushiki Kaisha Riken Saito
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 17:55
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/92; B01D53/94; B01D53/9404; B01D53/9409; B01D53/9413; B01D53/9418; B01D53/944; B01D53/9459; B01J; B01J23/00; B01J23/38; B01J23/54; B01J23/56; B01J23/64; B01J23/652; B01J23/6527; B01J23/66; B01J23/68; B01J23/683; B01J23/687; B01J35/00; B01J35/19; B01D2251/00; B01D2251/20; B01D2251/208; B01D2255/00; B01D2255/10; B01D2255/102; B01D2255/1021; B01D2255/1023; B01D2255/104; B01D2255/20; B01D2255/207; B01D2255/20723; B01D2255/20776; B01D2255/90; B01D2255/92; B01D2255/9202; B01D2255/9205; B01D2255/9207; B01D2258/00; B01D2258/01; B01D2258/012
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
208 words
An exhaust gas cleaner for removing nitrogen oxides by reduction and unburned components of carbon monoxide and hydrocarbons by oxidation from an exhaust gas containing nitrogen oxides and oxygen in an amount larger than its stoichiometric amount relative to said unburned components in said exhaust gas, wherein said exhaust gas cleaner is constituted by a first catalyst comprising a first porous inorganic oxide supporting 0.2-15 weight % of an Ag component alone or in combination with 1 weight % or less of a Pt component or 5 weight % or less of a W component and a second catalyst comprising a second porous inorganic oxide supporting 5 weight % or less of a Pt component and optionally 10 weight % or less of a W component, the weight percentages being expressed by metal basis, at least one of said first and second catalysts containing said W component, said Ag component consisting essentially of at least one of Ag and compounds thereof, said Pt component of said first and second catalysts consisting essentially of at least one of Pt, Pd, Ru, Rh, Ir and Au, and said W component of said first and second catalysts consisting essentially of at least one of W, V, Mn, Mo, Nb and Ta.
Claim 2
Dependent Claim
77 words
The exhaust gas cleaner according to claim 1, wherein said first catalyst comprises a first porous inorganic oxide supporting 0.2-15 weight % of at least one of Ag and compounds thereof, and said second catalyst comprises a second porous inorganic oxide supporting 5 weight % or less of at least one of Pt, Pd, Ru, Rh, Ir and Au and 10 weight % or less of at least one of W, V, Mn, Mo, Nb and Ta.
Claim 3
Dependent Claim
75 words
The exhaust gas cleaner according to claim 1, wherein said first catalyst comprises a first porous inorganic oxide supporting 0.2-15 weight % of at least one of Ag and compounds thereof and 2 weight % or less of at least one of W, V, Mn and Mo, and said second catalyst comprises a second porous inorganic oxide supporting 5 weight % or less of at least one of Pt, Pd, Ru, Rh, Ir and Au.
Claim 4
Dependent Claim
95 words
The exhaust gas cleaner according to claim 1, wherein said first catalyst comprises a first porous inorganic oxide supporting 0.2-15 weight % of at least one of Ag and compounds thereof and 5 weight % or less of at least one of W, V, Mn, Mo, Nb and Ta, and said second catalyst comprises a second porous inorganic oxide supporting 5 weight % or less of at least one of Pt, Pd, Ru, Rh, Ir and Au and 10 weight % or less of at least one of W, V, Mn, Mo, Nb and Ta.
Claim 5
Dependent Claim
95 words
The exhaust gas cleaner according to claim 1, wherein said first catalyst comprises a first porous inorganic oxide supporting 0.2-15 weight % of at least one of Ag and compounds thereof and 1 weight % or less of at least one of Pt, Pd, Ru, Rh, Ir and Au, and said second catalyst comprises a second porous inorganic oxide supporting 5 weight % or less of at least one of Pt, Pd, Ru, Rh, Ir and Au and 10 weight % or less of at least one of W, V, Mn, Mo, Nb and Ta.
Claim 6
Dependent Claim
43 words
The exhaust gas cleaner according to any one of claims 1 to 5, wherein said first catalyst is disposed on an inlet side of said exhaust gas cleaner and said second catalyst is disposed on an outlet side of said exhaust gas cleaner.
Claim 7
Dependent Claim
69 words
The exhaust gas cleaner according to any one of claims 1 to 6, wherein said first porous inorganic oxide is at least one ceramic selected from the group consisting of alumina and alumina-based composite oxides containing at least one of silica, titania and zirconia, and said second porous inorganic oxide is at least one ceramic selected from the group consisting of titania, alumina, zirconia, silica and composite oxides thereof.
Claim 8
Dependent Claim
29 words
The exhaust gas cleaner according to any one of claims 1 to 7, wherein said first and second catalysts are coated on a ceramic substrate or a metal substrate.
Claim 9
Dependent Claim
29 words
The exhaust gas cleaner according to any one of claims 1 to 8, wherein said first and second porous inorganic oxides are in the form of pellet or granule.
Claim 10
Independent Claim
163 words
A method for removing nitrogen oxides by reduction and unburned components of carbon monoxide and hydrocarbons by oxidation from an exhaust gas containing nitrogen oxides and oxygen in an amount larger than its stoichiometric amount relative to said unburned components in said exhaust gas, which comprises: disposing an exhaust gas cleaner as defined in any one of claims 1 to 10 in a flow path of said exhaust gas; introducing into said exhaust gas at least one reducing agent of hydrocarbons and oxygen-containing organic compounds having at least two carbon atoms or a fuel containing said at least one reducing agent on an upstream side of said exhaust gas cleaner; and bringing the resulting exhaust gas containing said reducing agent into contact with said exhaust gas cleaner at a temperature of 150-650°C, thereby causing a reaction of said nitrogen oxides with said reducing agent to remove said nitrogen oxides and unburned components of carbon monoxide and hydrocarbons by oxidation from said exhaust gas.
References Cited (Backward Citations)
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