摘要:
A process for isomerizing an aromatic C8 cut uses a catalyst which comprises: at least one ITQ-6 zeolite; at least one metal from group VIII of the periodic table; at least one binder; optionally, at least one metal selected from the group formed by elements from groups IIIA, IVA and VIIB of the periodic table; and optionally, sulphur.
摘要:
The invention concerns a process for reducing emissions of oxides of nitrogen in a medium which is super-stoichiomeitric in oxidising agents, comprising: a) a step for oxidising at least a portion of the oxides of nitrogen in the presence of an oxidation material; b) a step for injecting organic compounds which comprise at least one atom selected from carbon, hydrogen, oxygen and nitrogen; c) a step for adsorbing at least a portion of the organic compounds onto an adsorption material in the form of molecular species and/or carbonaceous residues; d) a step for selective reduction of at least a portion of the oxides of nitrogen to molecular nitrogen by at least a portion of the molecular species and/or carbonaceous residues formed on the adsorption material.
摘要翻译:本发明涉及一种减少氧化剂中超化学计量的介质中氮氧化物排放的方法,包括:a)在氧化物质存在下氧化至少一部分氮氧化物的步骤; b )用于注入包含至少一个选自碳,氢,氧和氮的原子的有机化合物的步骤; c)将至少一部分有机化合物以分子种类和/或形式吸附到吸附材料上的步骤 碳质残渣; d)通过在吸附材料上形成的分子种类和/或碳质残渣的至少一部分,将至少一部分氮氧化物选择还原成分子氮的步骤。
摘要:
A catalyst which is active and selective for the reduction of nitrogen oxides to molecular nitrogen by reducing agents in a medium which is superstoichiometric in oxidizing agents such as carbon monoxide, hydrogen, hydrocarbons, alcohols and other oxygen-containing organic compounds. The active phase of this catalyst is as follows: at least one inorganic refractory oxide; at least one rare earth element (A); at least one alkaline-earth element (B); at least one platinum group metal (C); and at least one silver or gold metal (D). Impregnation of (C) is advantageously followed by heat treatment in a reducing atmosphere.
摘要:
A production process for supported catalysts is described comprising: (a) preparing a coating suspension containing at least one refractory inorganic oxide and at least some of the elements intended to constitute catalytically active phase (A); (b) filling at least part of the open porosity of a support with this suspension; (c) drying the filled support by centrifuging; (d) a thermal treatment of the support to obtain a support coated by a wash coat; (e) optionally impregnating the coated support with a solution containing the rest of, or elements of, catalytically active phase (A); and (f) thermally activating the catalyst. This preparation process is of particular interest in the production of catalysts for treating exhaust gases of internal combustion engines, where the wash coat deposited on a support comprises in particular a refractory inorganic oxide, iron oxide and cerium oxide and, by way of a catalytically active element, at least one noble metal such as platinum, rhodium or palladium.
摘要:
Processes for the catalytic combustion of hydrocarbons, carbon monoxide, hydrogen, or mixtures thereof (processes with one or more catalytic stages) and processes of abating the pollution produced by the exhaust gases of vehicles that run on natural gas using a non-selective oxidation catalyst. The non-selective oxidation catalyst comprises a monolithic substrate, a porous support with a refractory inorganic oxide base and an active phase that consists of cerium, zirconium, iron, and at least one metal that is selected from the group that is formed by palladium and platinum is described; with the porous support content being between 200 and 400 g per liter of catalyst; with the cerium content being between 0.3 and 20% by weight relative to the porous support; with the zirconium content being between 0.3 and 20% by weight relative to the porous support; with the iron content being between 0.01 and 3.5% of iron by weight relative to the porous support; and with the palladium and/or platinum content being higher than 3 g per liter of catalyst.
摘要:
The invention relates to a catalyst comprising an assembly of at least one wire that comprises, in % weight, between 60 and 90% iron, and between 10 and 25% chromium, at least one metal selected from the group formed by platinum, rhodium, palladium, ruthenium, iridium, gold and silver having been deposited on the assembly, the outside contour of the cross-section of the wire being included in a ring whose area is between a circle with a 90 .mu.m diameter and a circle with a 5 mm diameter, the length of the wire being at least equal to 20 cm, and the assembly being mechanically integral, the wire having been subjected to a prior depositing of aluminum, in a proportion going up to 10% by weight in relation to the weight of the wire, followed by a redrawing.A preferred assembly corresponds to a knitted structure (1) in the shape of a sock.
摘要:
A method for preparing multi-metal catalysts including an active phase consisting of at least two metals, A and B, which are selected from groups VIII and IB of the periodic table, and a porous support. According to the method: firstly, at least a part of the porous support is impregnated with at least one precursor of metal A; secondly, activation is performed in a neutral or oxidizing atmosphere at a temperature of 120.degree.-800.degree. C. whereafter a treatment is carried out in a reduction medium at a temperature of 0.degree.-800.degree. C.; thirdly, at least a part of the support which was previously impregnated with the precursor of metal A is impregnated with at least one precursor of metal B; and fourthly, activation is performed in a neutral or oxidizing atmosphere at a temperature of 120.degree.-800.degree. C. The catalysts thereby obtained have improved stability, particularly when subjected to high temperatures, such as when they are used as post-combustion catalysts for exhaust gases from internal combustion engines, in which case metal A is platinum or palladium and metal B is platinum, palladium or rhodium, with the proviso that B is not the same as A.
摘要:
A catalyst comprising at least one porous support, at least some platinum, and at least a second group VIII metal which is different from platinum and iridium, said catalyst having been prepared in accordance with a process comprising a) impregnation of the support with at least one solution containing a platinum precursor, b) activation in a neutral or oxidizing atmosphere, at a temperature of between 120 and 800° C., c) activation in a reducing medium, at a temperature of between 0 and 800° C., d1) impregnation with an aqueous solution and d2) treatment with at least one hydrogen donor compound, at a temperature of less than 200° C., e) the impregnation of the support, which has already been impregnated with the platinum, with at least one solution containing a precursor of said second group VIII metal, and f) activation in a neutral, reducing, or oxidizing atmosphere, at a temperature of between 100 and 800° C.
摘要:
The invention concerns materials for adsorbing and desorbing oxides of nitrogen NO and NO2 present in exhaust gases, in particular from the internal combustion engines of automotive vehicles operating in a medium which is super-stoichiometric in oxidizing agents, which can desorb the oxides of nitrogen by elevating the temperature, with respect to an adsorption temperature, the structure of the materials being composed of phosphate tetrahedra and containing at least one element (A) from groups IVB, VB, VIB, VIIB, IVA, optionally at least one element (B) selected from the group formed by alkali elements IA, alkaline-earth elements IIA, rare earths IIIB and transition metals, and optionally at least one metal (C) selected from the group formed by the precious metals of the platinum family (group VIII). These materials are insensitive to the oxides of sulphur and carbon contained in the gas.
摘要:
A combustion catalyst comprising a monolithic substrate, a porous support based on refractory inorganic oxide and an active phase formed by cerium, iron and at least one metal selected from the group formed by palladium and platinum, the content of porous support being between 100 and 400 g per liter of catalyst; the content of cerium being between 0.3 and 20% by weight with respect to the porous support; the content of iron being between 0.01 and 3.5% of iron by weight with respect to the porous support; and the content of palladium and/or platinum being between 3 and 20 g per liter of catalyst. The catalyst of the invention is used in particular in processes for the catalytic combustion of hydrocarbons, carbon monoxide, hydrogen or mixtures thereof, in processes involving one or more catalytic stages.