摘要:
Catalysts, methods of preparing catalyst, and methods for treating exhaust gas streams are described. In one or more embodiments, a catalyst system includes an upstream zone effective to catalyze the conversion of a mixture of NOx and NH3 to N2, and a downstream zone effective for the conversion of ammonia to N2 in the presence or absence of NOx. In an embodiment, a method for preparing a catalyst system includes: first coating one end of a substrate along at least 5% of its length with an undercoat washcoat layer containing a material composition effective to catalyze the removal of ammonia; second coating with an overcoat layer containing a material composition effective to catalyze the conversion of a mixture of NOx and NH3 to N2. A method for treating the exhaust gas stream is provided, which includes injecting ammonia or an ammonia precursor into an exhaust gas stream of a vehicle, passing the engine exhaust gas stream containing NOx and NH3 through the upstream zone of a catalyst system to remove NOx and then passing the exhaust gas stream through the downstream zone of the catalyst system to remove NH3, as well as other oxidizable species such as hydrocarbons and CO.
摘要:
A process for continuous heterogeneously catalyzed partial dehydrogenation of at least one hydrocarbon to be dehydrogenated in a reactor which is manufactured from a composite material which consists, on its side in contact with the reaction chamber, of a steel B with specific elemental composition which, on its side facing away from the reaction chamber, either directly or via an intermediate layer of copper, or of nickel, or of copper and nickel, is plated onto a steel A with specific elemental composition, and also partial oxidations of the dehydrogenated hydrocarbon and the reactor itself.
摘要:
A process for stably operating a continuous preparation process for obtaining acrolein or acrylic acid or a mixture thereof from propane, in which the feed rate of fresh propane to the process is utilized as a correcting element for stable steady-state operation.
摘要:
A process for preparing acrolein or acrylic acid or a mixture thereof from propane, in which propane is dehydrogenated under heterogeneous catalysis in a reaction zone A and the propylene formed is partially oxidized heterogeneously in a reaction zone, reaction zone A being operated in loop mode and reaction gas mixture input stream A fed to the reaction zone A comprising added molecular hydrogen which is added to this input stream as late as possible.
摘要:
A process for preparing at least one target product by partial oxidation and/or ammoxidation of propylene, in which the propylene source used is a propane dehydrogenation, the propane used therein being obtained by a rectificative prepurification of crude propane.
摘要:
A process for the heterogeneously catalyzed gas-phase partial oxidation of an organic compound over a fixed catalyst bed present in a fixed-bed reactor having a plurality of catalyst tubes, in which the reduction of the quality of the catalyst load with increasing duration of operation is restored by a partial catalyst change, is described.
摘要:
A process for removing methacrolein from liquid phase P comprising acrylic acid as a main constituent and target product, and methacrolein as a secondary component in which the removal is effected by crystallization, the acrylic acid accumulating in the crystals formed and the methacrolein in the remaining mother liquor.
摘要:
A process for removing methacrylic acid from liquid phase P comprising acrylic acid as a main constituent and target product, and methacrylic acid as a secondary component in which the removal is effected by crystallization, the acrylic acid accumulating in the crystals formed and the methacrylic acid in the remaining mother liquor.
摘要:
The sequential production of a library of N different solids, in particular heterogeneous catalysts, where N within a day is an integer of at least 2, is performed by a) producing at least two different sprayable solutions, emulsions and/or dispersions of elements and/or element compounds of the chemical elements present in the catalyst and optionally of dispersions of inorganic support materials, b) continuously metering the at least two different solutions, emulsions and/or dispersions in a predefined ratio into a mixing apparatus in which the solutions, emulsions and/or dispersions are homogeneously mixed, c) continuously drying the mixture removed from the mixing apparatus and recovering the dried mixture, d) changing the ratios in step b) and repeating steps b), c) and d) (N-1) times until N different dried mixtures are obtained, e) optionally shaping and optionally calcining the mixtures to give the solids.
摘要:
A process for preparing a multimetal oxide material which contains the elements Mo, V and Te and/or Sb and at least one of the elements Nb, Ti, W, Ta and Ce and if desired promoters and has a specific X-ray diffraction pattern, in which process the last process step comprises washing with acidic liquids. In addition, a multimetal oxide material obtainable in such a way is used as a catalyst for heterogeneously catalyzed gas-phase partial oxidations and/or ammoxidation of hydrocarbons.