Kabushiki Kaisha Riken

Agency of Industrial Science and Technology

Hiroshi Kashiwagi of Director-general of Agency of Industrial Science

Other

Kozo Izuka, Director-general of Agency of Industrial Science and

Shunso Ishishara, Director-general of Agency of Industrial Science and

Jiro Hiraishi, Director-general of Agency of Industrial Science and

Kozo Izuka Director-general of Agency of Industrial Science & Technology

Kubushiki Kaisha Riken

Kiyohide Yoshida

Akira Abe

Gyo Muramatsu

Naoko Irite

Satoshi Sumiya

Tatsuo Miyadera

Mika Saito

Yoshikazu Takahashi

Nobuyuki Matsumura

Masataka Furuyama

Hideo Ohuchi

Akira Obuchi

Hyogoro Aoyama

Akihiko Ohi

Takashi Ibusuki

Kazuhiko Ogiwara

Seiji Makino

Shoji Mochida

Katsuji Onai

Koichi Mizuno

Atsushi Ogata

Hidenori Yoshiyama

Akira Nishiya

Akiniko Ohi

Hong He

Nitrogen oxides are removed from an exhaust gas containing nitrogen oxides and oxygen in a proportion larger than its stoichiometric proportion relative to unburned components in the exhaust gas, by (i) disposing an exhaust gas cleaner in a flow path, the exhaust gas cleaner comprising a first catalyst composed of 0.2-20 parts by weight (on a metal basis) of silver or silver oxide supported on a porous inorganic oxide, and a second catalyst composed of 1-50 parts by weight (on an oxide basis) of tungsten and/or vanadium supported on a porous inorganic oxide; (ii) introducing oxygen-containing organic compounds having 2 or more carbon atoms or a fuel containing the oxygen-containing organic compounds into the exhaust gas on the upstream side of the exhaust gas cleaner; and (iii) bringing the exhaust gas into contact with the exhaust gas cleaner at a temperature of 150-650&deg; C., thereby causing a reaction of the nitrogen oxides with the oxygen-containing organic compounds to remove the nitrogen oxides.

Exhaust gas cleaner and method for removing nitrogen oxides

Nitrogen oxides are removed from an exhaust gas containing nitrogen oxides and oxygen in a proportion larger than its stoichiometric proportion relative to unburned components in the exhaust gas, by (i) disposing an exhaust gas cleaner in a flow path, the exhaust gas cleaner comprising a first catalyst composed of 0.2-20 parts by weight (on a metal basis) of silver or silver oxide supported on a porous inorganic oxide, and a second catalyst composed of 1-50 parts by weight of tungsten and/or vanadium supported on a porous inorganic oxide; (ii) introducing oxygen-containing organic compounds having 2 or more carbon atoms or a fuel containing the oxygen-containing organic compounds into the exhaust gas on the upstream side of the exhaust gas cleaner; and (iii) bringing the exhaust gas into contact with the exhaust gas cleaner at a temperature of 150-650.degree. C., thereby causing a reaction of the nitrogen oxides with the oxygen-containing organic compounds to remove the nitrogen oxides.

An exhaust gas cleaner for removing nitrogen oxides by reduction from an exhaust gas containing nitrogen oxides, sulfur oxides, moisture, unburned or partially burned components and oxygen, a content of oxygen in the exhaust gas being larger than a stoichiometric amount required for completely oxidizing or burning the unburned or partially burned components, wherein the exhaust gas cleaner consists essentially of a first catalyst consisting essentially of a first porous inorganic oxide carrying at least one silver component, and at least one transition metal component selected from the group consisting of copper, iron, cobalt, nickel and compounds thereof; and a second catalyst selected from the group consisting of (a) a catalyst consisting essentially of a porous titania, (b) a catalyst consisting essentially of a second porous inorganic oxide carrying a titanium component, (c) a catalyst consisting essentially of the second porous inorganic oxide carrying at least one first component selected from the group consisting of copper, nickel, silver, cobalt and compounds thereof, at least one second component selected from the group consisting of titanium, zirconium and compounds thereof, and at least one third component selected from the group consisting of alkali metal elements and rare earth elements, and (d) a catalyst consisting essentially of the second porous inorganic oxide carrying a titanium component and at least one noble metal component selected from the group consisting of platinum, palladium, ruthenium, rhodium, iridium and gold.

Exhaust gas cleaner and method for cleaning exhaust gas

An exhaust gas cleaner consisting essentially of a first catalyst consisting essentially of a first porous inorganic oxide supporting 1.6-8.7 weight percent of an Ag component, on a metal basis, and a second catalyst consisting essentially of a second porous inorganic oxide supporting 0.1-3.8 weight percent of a Pt component and 1-9.9 weight percent of a W component, each weight percent on a metal basis. The Ag component includes Ag or a compound thereof. The Pt component includes Pt, Pd, Ru, Rh, Ir, and Au. The W component includes W, V, Mn, Mo, Nb, and Ta.

Exhaust gas cleaner

An exhaust gas cleaner is constituted of an Ag catalyst carrying an Ag component and a base metal catalyst carrying a Cu component and optionally W, V, Mo components, and a noble metal catalyst carrying a noble metal component. The base metal catalyst and the noble metal catalyst may be physically mixed to form a mixed catalyst. Another exhaust gas cleaner is constituted of the first Ag catalyst carrying an Ag component, the second Ag catalyst carrying an Ag component, a base metal catalyst carrying a Cu component and optionally W, V, Mo components, and a noble metal catalyst carrying a noble metal component. The second Ag catalyst carries the Ag component in an amount larger than that of the first Ag catalyst. The noble metal catalyst is physically mixed with the base metal catalyst to form a mixed catalyst. The exhaust gas cleaner can effectively remove nitrogen oxides in a wide temperature range of exhaust gas.

An exhaust gas cleaner being constituted by a first catalyst of a first porous inorganic oxide supporting a silver component in combination with a W component and a second catalyst of a second porous inorganic oxide supporting a Pt component and optionally a W component. The Ag component may include Ag and compounds thereof, the Pt component may include Pt, Pd, Ru, Rh, Ir, and Au, and the W component may include W, V, Mn, Mo, Nb, and Ta. The W component effectively catalyzes the reduction of nitrogen oxides by ammonia to enhance the removal efficiency of the exhaust gas cleaner.

Nitrogen oxides are removed from an exhaust gas containing nitrogen oxides and oxygen in an amount larger than its stoichiometric amount relative to unburned components in the exhaust gas, by (i) disposing an exhaust gas cleaner in a flow path of the exhaust gas, the exhaust gas cleaner comprising 0.2-15 weight % (on a metal basis) of fine silver or silver oxides having an average diameter of 10-1,000 nm and supported on a porous inorganic oxide; (ii) introducing hydrocarbons and/or oxygen-containing organic compounds into the exhaust gas on the upstream side of the exhaust gas cleaner; and (iii) bringing the exhaust gas into contact with the exhaust gas cleaner at a temperature of 200.degree.-600.degree. C., thereby causing a reaction of nitrogen oxides with the hydrocarbons and/or oxygen-containing organic compounds.

Comprising supported silver sulfate or silver chloride or silver with

Nitrogen oxides are removed from an exhaust gas containing nitrogen oxides and oxygen in an amount larger than its stoichiometric amount relative to unburned components in the exhaust gas, by using an exhaust gas cleaner having Ag supported by a porous inorganic oxide body and second catalyst containing second catalytically active components supported by a porous inorganic oxide body. The second catalytically active components consist essentially of Cu and/or other metals such as alkali metal elements, rare earth elements, etc.

Exhaust gas cleaner and method of cleaning exhaust gas

Method for cleaning exhaust gas

A method of cleaning an exhaust gas using an exhaust gas cleaner constituted by a first catalyst comprising a first porous inorganic oxide supporting an Ag component, a W component and a Pt component and optionally a second catalyst comprising a second porous inorganic oxide supporting a Pt component alone or in combination with a 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.

An exhaust gas cleaner is constituted by a first catalyst carrying an Ag component, a second catalyst carrying an Ni component or two or more of an Ni component, Ag component and Cu component, and optionally a third catalyst carrying a noble metal component alone or in combination with a base metal component. The second and third catalysts may be physically mixed to form a mixed catalyst. Another exhaust gas cleaner is constituted by a mixed catalyst of a first catalyst carrying an Ag component and a second catalyst carrying an Ni component alone or in combination with a Cu component, and a third catalyst carrying a noble metal component alone or in combination with a base metal component. Still another exhaust gas cleaner is constituted by a first catalyst carrying an Ag component, a second catalyst which is a mixture of an Ni catalyst, Ag catalyst and Cu catalyst, and optionally a third catalyst carrying a noble metal component alone or in combination with a base metal component. The second and third catalyst may be physically mixed to form a mixed catalyst.

An exhaust gas cleaner is constituted by a first Ag catalyst, a second Ag catalyst, a transition metal catalyst selected from the group consisting of a Pt catalyst, a W catalyst, a W+Pt catalyst and a mixed catalyst of the Pt catalyst and the W catalyst. The second Ag catalyst and the Pt catalyst may be physically mixed together to form a mixed catalyst. Another exhaust gas cleaner is constituted by an Ag catalyst, a Cu catalyst and a W+Pt catalyst. The Cu catalyst and the W+Pt catalyst may be physically mixed together to form a mixed catalyst. Still another exhaust gas cleaner is constituted by a mixed catalyst of an Ag catalyst and a Cu catalyst. The exhaust gas cleaner can effectively remove nitrogen oxides in a wide temperature range of exhaust gas.

Growing community of inventors

Kumagaya, Japan

Kiyohide Yoshida