摘要:
A single layer high performance catalyst containing on an inert carrier body a catalytic coating comprising platinum, rhodium and various oxide materials. The catalyst contains a catalytic coating having at least one first support material selected from the group having a first active alumina, a ceria rich ceria/zirconia mixed oxide and a zirconia component, said at least one first support material being catalyzed with a first part of the total platinum amount of the catalyst, and a second support material catalyzed with the second part of the total platinum amount and with rhodium said second support material being a second active alumina.
摘要:
An oxidation catalyst for internal combustion engines which contains platinum on a finely divided support material and containing lead as a promoter. The catalytic activity of the oxidation catalyst can be increased greatly by promoting the catalyst with lead at a molar ratio of lead to platinum of 2:1. The light-off temperatures of the promoted catalyst are well below the corresponding temperatures for a conventional, lead-free catalyst.
摘要:
An oxygen storage material comprising cerium oxide and at least one second oxide of a metal M1 is disclosed as well as a process for manufacturing the material and the use of this material in an exhaust gas cleaning catalyst. In a preferred embodiment the oxygen storage material comprises particles from a Ce/M1 mixed oxide solid solution coated with an oxide of another metal M2. Metal M1 e.g. can be calcium or zirconium while metal M2 most preferably is aluminum.
摘要:
The present invention relates to an exhaust-gas purification system for the selective catalytic reduction of nitrogen oxides. The system includes at least one catalyst having catalytically active components for the selective catalytic reduction (SCR components). An NOx storage catalyst (5) is arranged upstream of the SCR catalyst (3) in the exhaust-gas purification system. For performing the selective catalytic reduction, metering means (8) for supplying a compound decomposable into ammonia is provided between the NOx storage catalyst and the SCR catalyst (3). At low exhaust-gas temperatures, the NOx storage catalyst (5) adsorbs the nitrogen oxides contained in the exhaust gas and desorbs them only at rising exhaust-gas temperatures, so that they can afterwards be converted by the SCR catalyst (3) which is active then. This results in an altogether improved conversion rate for the nitrogen oxides.
摘要:
The invention relates to a method and an apparatus of operating a drive system comprising an engine and an exhaust gas purification unit containing a catalyst, where the engine emits an exhaust gas having an exhaust gas temperature and the catalyst has a catalytic activity for the purification of the exhaust gas. In the method, an aging-induced decrease in the catalytic activity of the catalyst is compensated at least part of the time by increasing the exhaust gas temperature of the engine.
摘要:
The invention relates to a method of determining activity and aging behavior of a catalyst. For this purpose, two independent substreams of combustion offgases are produced and mixed before coming into contact with the catalyst. The first substream of combustion offgases is preferably produced by burning a motor fuel and forms the major part of the combustion offgases. The second substream of combustion offgases is produced by means of a gas burner whose air ratio can be adjusted within a wide range. Mixing of this second substream of combustion offgases into the first substream enables the composition of the total stream to be set in a defined manner.
摘要:
The present invention relates to a catalyst for the purification of exhaust gases from an internal combustion engine, which comprises a catalytically active coating on an inert ceramic or metal honeycomb body, said coating comprising at least one platinum group metal selected from the group consisting of platinum, palladium, rhodium and iridium on a fine, oxidic support material. As an oxidic support material, the catalyst comprises a low-porosity material on the basis of silicon dioxide that comprises aggregates of essentially spherical primary particles having an average particle diameter of between 7 and 60 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 process for producing electrical energy with the aid of a fuel cell, which includes the steps of reforming an organic fuel, removing carbon monoxide from the reformate, and reacting the hydrogen present in the reformate with oxygen, in a fuel cell, to thereby produce electrical energy. The carbon monoxide is removed from the reformate by treating the reformate in a bioreactor which contains a thermophilic microorganism strain which metabolizes carbon monoxide, under anaerobic conditions, to give carbon dioxide and hydrogen.