摘要:
A metal-doped or metal-exchanged zeolite is disclosed, wherein the doping metal is present in the zeolite in the form of individual atoms i.e. as monomeric and/or dimeric species. Further, a process for the preparation of such a metal-doped or metal-exchanged zeolite is disclosed. The metal-doped zeolites are useful, in particular, as catalysts for the reduction of nitrogen oxides.
摘要:
A filter for filtering particulate matter (PM) from exhaust gas emitted from a compression ignition engine, which filter comprising a porous substrate having inlet surfaces and outlet surfaces, wherein the inlet surfaces are separated from the outlet surfaces by a porous structure containing pores of a first mean pore size, wherein the porous substrate is coated with a wash coat comprising a plurality of solid particles comprising a molecular sieve promoted with at least one metal wherein the porous structure of the wash coated porous substrate contains pores of a second mean pore size, and wherein the second mean pore size is less than the first mean pore size.
摘要:
A zeolite related to zeolite L and having a characteristic cylindrical morphology may be prepared from a crystallization gel comprising (in mole ratios of oxides):K.sub.2 O/SiO.sub.2 --0.22-0.36H.sub.2 O/K.sub.2 O--25-90SiO.sub.2 /Al.sub.2 O.sub.3 --6-15and preferably with the mole ratio H.sub.2 O/K.sub.2 O+Al.sub.2 O.sub.3 +SiO.sub.2 being at least 8. The cylindrical Zeolite L may be used as a catalyst base in aromatization of acyclic hydrocarbons with high benzene yields being sustained over commerically feasible periods.
摘要:
A synthetic offretite having a capacity for sorbing benzene and other large molecules is prepared from an aqueous nutrient containing tetramethyl ammonium hydroxide, potassium hydroxide, and a suitable mixture of reactive aluminosilicate minerals, usually comprising sorptive silica.
摘要:
The present disclosure provides msect-4 molecular sieves with OFF and ERI topologies, a preparation method therefor, and applications thereof. An eight-membered ring small pore molecular sieve used as a raw material is dispersed in an aqueous phase. Following that, caustic potash, an aluminum source, and an organic structure-directing agent (OSDA) are added. The pH value is then adjusted to be greater than 10, and a silicon source is introduced to attain the desired silicon-aluminum ratio, followed by stirring reaction, aging, crystallization, filtration, washing, ammonia exchange reaction, drying, and calcination. The msect-4 molecular sieves with OFF and ERI topologies, the preparation method therefor, and applications exhibit excellent hydrothermal stability, a plurality of adsorption sites exposed by a regular bone-like structure, and a large specific surface area. Consequently, this molecular sieves find applicability across various technical fields including selective catalytic reduction, passive adsorption, and catalytic cracking, and has broad application prospects.
摘要:
Certain selective catalytic reduction (SCR) articles, systems and methods provide for high NOx conversion while at the same time low N2O formation. The articles, systems and methods are suitable for instance for the treatment of exhaust gas of diesel engines. Certain articles have zoned coatings containing copper-containing molecular sieves disposed thereon, where for example a concentration of catalytic copper in an upstream zone is lower than the concentration of catalytic copper in a downstream zone.
摘要:
The present invention relates to a catalyst comprising a macroporous noble metal-containing zeolite material and a porous SiO2-containing binder, wherein the catalyst has a proportion of micropores of more than 70%, based on the total pore volume of the catalyst. The invention is additionally directed to a process for preparing the catalyst and to the use of the catalyst as an oxidation catalyst.
摘要:
A cold start catalyst is disclosed. The cold start catalyst comprises a zeolite catalyst and a supported platinum group metal catalyst. The zeolite catalyst comprises a base metal, a noble metal, and a zeolite. The supported platinum group metal catalyst comprises one or more platinum group metals and one or more inorganic oxide carriers. The invention also includes an exhaust system comprising the cold start catalyst. The cold start catalyst and the process result in improved NOx storage and NOx conversion, improved hydrocarbon storage and conversion, and improved CO oxidation through the cold start period.
摘要:
A process for reforming a hydrocarbon fraction having a limited proportion of C.sub.9 + hydrocarbons. A hydrocarbon fraction is separated into a light fraction and a heavy fraction, the light fraction containing less than 10% by volume of C.sub.9 + hydrocarbon. The light fraction is reformed in the presence of a monofunctional catalyst, and the heavy fraction is reformed in the presence of a bifunctional catalyst.
摘要:
A process is provided for loading and uniformly distributing platinum onto a Zeolite-L. The Zeolite-L is contacted with an aqueous solution containing a platinum salt and a non-platinum metal salt, wherein the non-platinum metal salt is present in solution in an amount which is critical to preventing the formation of acid sites as well as avoiding an excess of metal ions in the form of a salt which could block the pores of the Zeolite-L. The Zeolite-L is then aged to allow the platinum to migrate and uniformly distribute throughout the Zeolite.