The present invention relates to an exhaust gas treatment system for treating an exhaust gas stream leaving an internal combustion engine, wherein said exhaust gas treatment system comprises (i) a first catalyst comprising a coating and a first substrate, wherein the coating comprises a vanadium oxide supported on a first oxidic support comprising titanium; (ii) a hydrocarbon injector for injecting a fluid comprising hydrocarbons into the exhaust gas stream exiting the outlet end of the first catalyst according to (i); (iii) a second catalyst comprising a coating and a second substrate, wherein the coating comprises palladium on a second oxidic support comprising one or more of zirconium, silicon, aluminum and titanium.

The present invention relates to an exhaust gas treatment system for treating an exhaust gas stream leaving an internal combustion engine, wherein said exhaust gas treatment system comprises (i) a first catalyst comprising a coating and a first substrate, wherein the coating comprises a vanadium oxide supported on a first oxidic support comprising titanium; (ii) a hydrocarbon injector for injecting a fluid comprising hydrocarbons into the exhaust gas stream exiting the outlet end of the first catalyst according to (i); (iii) a second catalyst comprising a coating and a second substrate, wherein the coating comprises palladium on a second oxidic support comprising one or more of zirconium, silicon, aluminum and titanium.

An organic base modified composite catalyst for producing ethylene by hydrogenation of carbon monoxide is a composite catalyst and formed by compounding component I and component II in a mechanical mixing mode. The active ingredient of the component I is a metal oxide; the component II is an organic base modified zeolite of MOR topology; and a weight ratio of the active ingredients in the component I to the component II is 0.1-20, and preferably 0.3-8. The reaction process has an extremely high product yield and selectivity. The selectivity of C.sub.2-C.sub.3 olefins is as high as 78-87%; the selectivity of hydrocarbon products with more than 4 C atoms is less than 10%; the selectivity of a methane side product is extremely low (<9%); and meanwhile, the selectivity of the ethylene is 75-82%.

An organic base modified composite catalyst for producing ethylene by hydrogenation of carbon monoxide is a composite catalyst and formed by compounding component I and component II in a mechanical mixing mode. The active ingredient of the component I is a metal oxide; the component II is an organic base modified zeolite of MOR topology; and a weight ratio of the active ingredients in the component I to the component II is 0.1-20, and preferably 0.3-8. The reaction process has an extremely high product yield and selectivity. The selectivity of C.sub.2-C.sub.3 olefins is as high as 78-87%; the selectivity of hydrocarbon products with more than 4 C atoms is less than 10%; the selectivity of a methane side product is extremely low (<9%); and meanwhile, the selectivity of the ethylene is 75-82%.

Provided is a catalyst with a more satisfactory denitration efficiency at low temperatures during a selective catalytic reduction reaction having ammonia as the reductant, compared to prior art techniques.

This denitration catalyst contains vanadium oxide. The denitration catalyst has a carbon content of 0.05% by weight or more, and has a deficiency site wherein oxygen deficiency occurs within the crystal structure.

Provided is a catalyst with a more satisfactory denitration efficiency at low temperatures during a selective catalytic reduction reaction having ammonia as the reductant, compared to prior art techniques.

This denitration catalyst contains vanadium oxide. The denitration catalyst has a carbon content of 0.05% by weight or more, and has a deficiency site wherein oxygen deficiency occurs within the crystal structure.

Provided is a catalyst having better denitration efficiency at low temperatures compared to the prior art, during a selective catalytic reduction reaction in which ammonia is used as a reducing agent. This denitration catalyst contains vanadium oxide including vanadium pentoxide and has a defect site in which oxygen deficiency occurs in a crystal structure of the vanadium pentoxide.

Provided is a catalyst having better denitration efficiency at low temperatures compared to the prior art, during a selective catalytic reduction reaction in which ammonia is used as a reducing agent. This denitration catalyst contains vanadium oxide including vanadium pentoxide and has a defect site in which oxygen deficiency occurs in a crystal structure of the vanadium pentoxide.

The present invention pertains to a catalyst for use in the selective catalytic reduction (SCR) of nitrogen oxides cornprising: —a ceramic candle filter substrate and—a coating which comprises an oxidic metal carrier comprising an oxide of titanium and a catalytic metal oxide which comprises an oxide of vanadium wherein the mass ratio vanadium/titanium is 0.03 to 0.27, —wherein the mass ratio is calculated based on the mass of vanadium metal and titanium metal, and—wherein the catalyst comprises from about 1 to about 10% by weight of the catalytically active material, and—wherein the catalytic metal oxide is adsorbed onto the surface of the oxidic metal carrier.

Provided is a combustion system in which a catalyst having superior denitration efficiency at a low temperature compared with those used in the conventional techniques is used in a selective catalytic reduction reaction using ammonia as a reducing agent. A combustion system equipped with: a denitration device which is arranged in the exhaust passage and can remove a nitrogen oxide from the exhaust gas with a denitration catalyst. In the combustion system, the denitration device is arranged on the downstream side of the dust collection device in the exhaust passage, and the denitration catalyst is one which contains vanadium oxide as the main component and in which the content of a second metal in terms of oxide content is 1 to 40 wt % inclusive, wherein the second metal comprises at least one metal element selected from the group consisting of Co, W, Mo, Nb, Ce, Sn, Ni, Fe, Cu, Zn and Mn.