摘要:
A process for preparing a catalyst which has a catalytically active coating of high surface area finely divided materials and catalytically active components on an inert carrier structure. A powder mixture of the finely divided materials used is impregnated with a solution of precursor compounds of the catalytically active components. By suitable combination of the finely divided materials and the precursor compounds and appropriate management of the impregnation process, a highly dispersed deposition and adsorption of the catalytically active components is ensured on the finely divided materials. Then ai aqueous coating dispersion is produced using the impregnated powder mixture and the carrier structure is coated therewith. The coating is then dried and calcined.
摘要:
A catalyst system for the treatment of exhaust gases from a diesel engine includes a first and a second catalyst reducing catalyst arranged in series in an exhaust gas treatment system. The first catalyst is located near the engine in a region of the exhaust gas treatment system in which the exhaust gas temperature reaches temperatures of more than 200° C. under full engine load. The second catalyst is located further from the engine in a region of the exhaust gas treatment system in which the exhaust gas temperature reaches a maximum of 500° C. under full engine load. The maximum nitrogen oxides reduction in the first catalyst takes place at a lower temperature than the maximum nitrogen oxides reduction in the second catalyst.
摘要:
A catalyst for purifying the exhaust gases of diesel engines, which catalyst contains at least one zeolite and, additionally, at least one of the support oxides aluminum oxide, silicon dioxide, titanium dioxide and aluminum silicate and at least one of the noble metals platinum, palladium, rhodium and iridium. In this catalyst the atoms of the noble metals have a mean oxidation number of less than +2.5, on average more than 3 metal ligands and less than 3 oxygen ligands and are present on the zeolites and support oxides in the form of crystallites having a mean particle size of from 1 to 6 nm.
摘要:
The invention relates to a process for the coating of a catalyst support with a catalytically active coat using a coating dispersion, the catalyst support containing at least two partial structures which differ in their absorptivity for the coating dispersion. The process is characterised in that the absorptivity of the partial structures is modified relative to one another by precoating of the catalyst support with a material which can be burnt out or with liquid, and the catalytic coat is then applied to the filter body in a known manner, dried and/or calcined.
摘要:
A honeycomb body made from a ceramic material with improved radial pressure resistance that is of cylindrical shape and features a first and a second end face and a cylindrical shell and that is traversed from one end face to the other by axially parallel channels formed by channel walls and distributed across the cross section of the honeycomb body in a regular grid pattern, in which design an outer marginal zone of the honeycomb body, the thickness of which amounts to several channel diameters, encloses a central area. The increase in radial pressure resistance of the honeycomb body is achieved by reinforcing the ceramic material of the cylindrical shell and of the channel walls in the outer marginal zone of the honeycomb body by depositing on or in it one or several inorganic substances for the purpose of increasing its mechanical stability.
摘要:
A powdered catalyst material based on aluminum oxide, which contains at least one basic metal oxide and at least one noble metal from the platinum group of the Periodic Table of Elements in addition to aluminum oxide. The catalyst material is obtainable by loading a support material already stabilized by basic oxides by renewed impregnation with further basic oxides. After drying and calcining this post-impregnated material at temperatures below 800° C., the catalytically active noble metals are also incorporated into the support material by impregnation.
摘要:
A process for coating, with a suspension, a ceramic honeycomb body which has a cylindrical shape with two flat end-faces and one jacket, and through which channels parallel to the axis, formed by channel walls, run from one flat end-face to the other, the honeycomb body being coated by suitable processes. The honeycomb body is partially wetted and then coated.
摘要:
A sulfur oxide storage material contains a magnesium-aluminum spinel (MgO.Al2O3) and can be used as a so-called “sulfur trap” to remove sulfur oxides from oxygen-containing exhaust gases of industrial processes. In particular, it can be used for the catalytic purification of exhaust gas from internal-combustion engines to remove the sulfur oxides from the exhaust gas in order to protect the exhaust gas catalysts from sulfur poisoning. The material displays a molar ratio of magnesium oxide to aluminum oxide in the range of over 1.1:1, and the magnesium oxide present in stoichiometric excess is homogeneously distributed in a highly disperse form in the storage material.
摘要翻译:硫氧化物储存材料含有镁 - 铝尖晶石(MgO·Al 2 O 3),并且可以用作所谓的“硫阱”,以从工业过程的含氧废气中除去硫氧化物。 特别地,其可以用于从内燃机排出的废气的催化净化,以从废气中除去硫氧化物,以保护废气催化剂免受硫中毒。 该材料显示氧化铝与氧化铝的摩尔比在1.1:1以上,以化学计量过量存在的氧化镁以高分散形式均匀地分布在储存材料中。
摘要:
The invention relates to a process for the coating of a catalyst support with a catalytically active coat using a coating dispersion, the catalyst support containing at least two partial structures which differ in their absorptivity for the coating dispersion. The process is characterized in that the absorptivity of the partial structures is modified relative to one another by precoating of the catalyst support with a material which can be burnt out or with liquid, and the catalytic coat is then applied to the filter body in a known manner, dried and/or calcined.
摘要:
A catalyst for purifying the exhaust gases from diesel engines. The catalyst contains a zeolite mixture of several zeolites with different moduli and platinum group metals as well as further metal oxides from the group aluminum silicate, aluminum oxide and titanium oxide, wherein the aluminum silicate has a ratio by weight of silicon dioxide to aluminum oxide of 0.005 to 1 and the platinum group metals are deposited on only the further metal oxides.