摘要:
A material and a process for adsorbing and desorbing nitrogen oxides in exhaust gas systems of engines running on a lean mixture, which does not require a prior oxidation step, wherein a mixed oxide which has an oxygen-rich orthorhombic structure is used which changes to an oxygen-poor tetragonal structure as a function of temperature.
摘要:
A catalyst and a process for producing the catalyst are provided. For the catalytic reduction of NO.sub.x and for the oxidation of hydrocarbons, the catalyst contains a spinel containing the metals copper, zinc and aluminum.
摘要:
A catalyst and a process for producing the catalyst are provided. For the catalytic reduction of NO.sub.x and for the oxidation of hydrocarbons, the catalyst contains a spinel containing the metals copper, zinc and aluminum.
摘要:
The invention provides a catalyst, and a process for preparing the same, for the catalytic reduction of NO.sub.x and for the oxidation of hydrocarbons. The catalyst contains a copper oxide-zinc oxide-aluminum oxide spinel and a zeolitic support material.
摘要:
An exhaust gas purification device includes a porous body of catalytic material of the general formula AaBbO4 disposed in an exhaust gas stream of an engine. The porous body of catalytic material has a characteristic response temperature above which it is catalytically active to reduce pollutants in the presence of a reducing agent. The porous body stores at least 20% by volume hydrocarbons at temperatures below the response temperature. A represent at least one element selected from Mg, Ca, Mn, Fe, Ni, Co, Cu, Zn, Sn, Ti and A+B is less than 3, A is greater than 0 and B greater than 0.
摘要:
A process for the catalytic reduction of NO.sub.x, the reduction taking place in the presence of a catalyst which comprises(a) from 20 to 97 wt % of A.sub.2 O.sub.3,(b) from 1 to 40 wt % of CuO,(c) from 1 to 50 wt % of ZnO,(d) from 1 to 40 wt % of Ag,(e) from 0 to 2 wt % of Pt,(f) from 0 to 20 wt % of oxides of rare earth metals, elements of the 3rd subgroup of the Periodic Table of the Elements or mixtures thereof,based on the total weight of the components (a) to (e), which adds up to 100 wt %, wherein, in each case, up to half the weight of the component (a) may be replaced by Fe.sub.2 O.sub.3, Cr.sub.2 O.sub.3, Ga.sub.2 O.sub.3 or mixtures thereof, of the component (b) by CoO, of the component (c) by MgO, of the component (d) by Au and of the component (e) by Pd, Ru, Os, Ir, Rh, Re or mixtures thereof, is used for reducing NO.sub.x, especially in combustion off-gases, the components (a), (b) and (c) forming a spinel which is doped with the components (d), (e) and (f).
摘要:
The present invention is directed to a purification device that includes a porous body and a catalyst. To reduce the emission of pollutants, a pollutant-containing stream of gas flows through the porous body.
摘要:
A catalyst and a method for producing the catalyst, for catalytic reduction of NO.sub.x and oxidation of hydrocarbons, the catalyst comprises a zinc, copper and aluminum spinel to which, at least one element selected from palladium, platinum, rhodium, ruthenium, osmium, iridium, rhenium and/or rare earth metals, such as lanthanum and cerium, vanadium, titanium, niobium, molybdenum, tungsten and/or salts thereof and/or oxides thereof has been added.
摘要:
NO.sub.x, where x is 1 and 2, in exhaust gases is reduced over heterogeneous catalysts with hydrocarbons, carbon monoxide, hydrogen or mixtures thereof in the presence of oxygen from 100 to 650.degree. C. and an absolute pressure of from 0.5 to 50 bar by a process in which the heterogeneous catalysts used are bimodal or polymodal compounds of the general formula IA.sub.1-x M.sub.2 O.sub.4 (I),which, if required, are doped with rare earth metals, noble metal, titanium, vanadium, molybdenum, tungsten or mixtures thereof, and whereA is magnesium, calcium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, tin or mixtures thereof,M is aluminum, gallium, indium, tin, chromium, manganese, iron, cobalt, nickel, copper, zinc or mixtures thereof andx is from 0 to 0.99,whose oxygen atoms are in a cubic close packed arrangement and A is present in the tetrahedral sites and M in the octahedral sites, it also being possible for A to occupy octahedral sites if an equivalent amount of M occupies tetrahedral sites.
摘要:
The present invention relates to a method for operating a purification device, to a purification device and to the use of same. To reduce the emission of pollutants, a filter body through which a fluid can flow and comprising a catalyst, is exposed to a stream of gas which is to be purified. Before the gas enters the catalyst, a reducing agent is added in the flow direction of the gas, and after a certain treatment point, during which the gas, which is to be purified, is flowing in the catalyst, reducing agent is added once more to the flowing gas by a feeding mechanism and contact with the catalyst is maintained.