Catalysts for conversion of nitrogen oxides comprises a porous ceramic carrier, and 0.1 to 10% by weight of copper oxide in terms of copper metal, 0.1 to 20% by weight of lanthanum oxide in terms of lanthanum metal and 0.01 to 12% by weight of zirconium oxide in terms of zirconium metal, based on the weight of the carrier, these oxides being supported on the carrier. The catalysts are brought in contact with a gas containing nitrogen oxides in the presence of ammonia and sulfur oxides, thereby decomposing and converting the nitrogen oxides.
An improved process for the simultaneous separation of sulfur and nitrogen oxides from a gaseous mixture containing said oxides and oxygen is disclosed. The gaseous mixture and ammonia are contacted with a solid sulfur oxides acceptor comprising copper, copper oxide, or mixture thereof dispersed on a carrier material in combination with a nitrogen oxides conversion catalyst consisting of a rare earth metal, metal oxide or mixture thereof.
The invention relates to a process for eliminating nitrogen oxides and sulphur oxides from a stream of flue gas containing nitrogen oxides and sulphur oxides comprising the steps of (a) adding ammonia to the stream of flue gas and contacting the resulting stream, at a temperature of 250.degree.-450.degree. C., with a reduction catalyst for selective reduction of nitrogen oxides into nitrogen and water, the molar ratio of ammonia to nitrogen oxides being in the range of 0.6-1.8, (b) contacting the stream from step (a), at a temperature of 300.degree.-470.degree. C., with an oxidation catalyst for oxidation of unreacted ammonia into nitrogen and water and simultaneous oxidation of sulphur dioxide into sulphur trioxide, and (c) cooling the stream from step (b) for condensation of sulphur trioxide in the form of sulphuric acid. The products of the process of the invention are steam, nitrogen, and concentrated sulphuric acid of commercial quality giving no waste disposal problems.
A process for the removal of nitrogen oxides from a waste gas containing said oxides in conjunction with sulfur oxides which comprises contacting said waste gas with ammonia as a reducing agent at temperatures of from 250.degree. to 550.degree. C in the presence of a catalyst wherein an active component containing iron or copper as the active metal and a sulfate of aluminum are supported on a silica carrier.
An improved process for the simultaneous separation of sulfur and nitrogen oxides from a gaseous mixture containing said oxides and oxygen is disclosed. The gaseous mixture and ammonia are contacted with a solid sulfur oxides acceptor comprising copper, copper oxide, or mixture thereof dispersed on a carrier material, and wherein said solid acceptor is subjected to cyclic regeneration in contact with a reducing gas, is disclosed. The solid acceptor further contains a rare earth metal, metal oxide or mixture thereof which functions as a sulfur oxides acceptance regeneration promoter as well as a nitrogen oxides conversion catalyst.
A catalyst for reducing nitrogen oxides, carbon monoxide and hydrocarbons, the noxious components in exhaust gases from internal combustion engines, etc., comprising: a porous carrier of ceramic selected from the group consisting of alumina and alumina-magnesia spinel; and a catalyst ingredient supported thereon consisting essentially of zirconium oxide, cerium oxide and a metal selected from the group consisting of platinum, palladium and mixtures thereof.
