摘要:
The invention relates to particle filters having an open pore structure for separating particles from fluids, which, for modification of their properties or for treatment of the fluid to be filtered, are provided with additional metal oxides or mixed metal oxides and optionally with further catalytically active components. In particular, the invention relates to particle filters treated with a catalytically active material, which is used for the treatment of the waste gases from combustion processes, in particular for the treatment of the exhaust gases of internal combustion engines. By impregnation of the filter bodies in a solution of a metal oxide sol or a mixed metal oxide sol, the preformed sol particles are deposited on the pore surfaces. Consequently, catalytic activations of the filter with good temperature stability in combination with a moderate increase in the exhaust gas back-pressure are possible.
摘要:
The invention relates to a method for coating a catalyst carrier with a catalytically active coating by means of a coating dispersion, said catalyst carrier containing at least two partial structures which differ in terms of the capacity thereof for absorbing the coating dispersion. The inventive method is characterised in that the absorbency of each partial structure is changed by pre-coating the catalyst carrier with a burnt off material or a liquid, and the catalytic coating is then applied to the filter body, dried and/or calcinated in a known manner.
摘要:
The invention relates to the use of mixed oxides made of cerium oxide, zirconium oxide, rare earth sesquioxide and niobium oxide as catalytically active materials for the selective catalytic reduction of nitrogen oxides with ammonia or a compound that can decompose to form ammonia in the exhaust gas of internal combustion engines in motor vehicles that are predominantly leanly operated, and to compositions or catalysts which contain said mixed oxides in combination with zeolite compounds and/or zeolite-like compounds and are suitable for the denitrogenation of lean motor vehicle exhaust gases in all essential operating states.
摘要:
The invention relates to the production of fine-particle metal oxide powders containing alkali metals, said powders containing at least one alkali metal and at least one other metal from the group of transition metals, the other main group metals, lanthanides and actinides. Precursor compounds of said constituents are introduced into a pulsed reactor with a gas flow resulting from a flameless combustion, in a solid form or in the form of a solution or a suspension, where they are partially or fully reacted to form the desired multi-constituent metal oxide powder.
摘要:
The invention relates to a catalytic converter system for cleaning diesel engine emissions, comprising a first and a second catalytic converter arranged in an emission control system. Said system is characterized in that both catalytic converters are reducing catalysts, the first being located close to the engine in an area of the emission control system where the emission temperature reaches 300 DEG C at full engine load, and the second being located away from the engine in an area of the emission control system where the emission temperature reaches a maximum of 500 DEG C at full engine load, whereby the maximum reduction of nitrogen oxide by the first catalytic converter occurs at temperatures which are lower than the maximum nitrogen oxide reduction of the second catalytic converter.