To provide a catalyst for purifying a combustion exhaust gas and a method for purifying a combustion exhaust gas. The denitration catalyst used in a method for purifying a combustion exhaust gas of removing a nitrogen oxide in the exhaust gas by making the catalyst into contact with the combustion exhaust gas having an alcohol as a reducing agent added thereto, contains zeolite as a support having supported thereon a catalyst metal, in a powder X-ray diffraction (XRD) measurement of the denitration catalyst a ratio (relative peak intensity ratio) r=I/J of a height I of a diffraction peak at a diffraction angle (2?) of from 7.8 to 10.0? and a height J of a diffraction peak at a diffraction angle (2?) of from 28.0 to 31.0? being in a range of from 3.0 to 5.0.

Hydrocarbon (HC) traps are disclosed. The HC trap may include a first zeolite material having an average pore diameter of at least 5.0 angstroms and configured to trap hydrocarbons from an exhaust stream and to release at least a portion of the trapped hydrocarbons at a temperature of at least 225 C. The HC trap may also include a second zeolite material having an average pore diameter of less than 5.0 angstroms or larger than 7.0 angstroms. One or both of the zeolite materials may include metal ions, such as transition, Group 1A, or platinum group metals. The HC trap may include two or more discrete layers of zeolite materials or the two or more zeolite materials may be mixed. The multiple zeolite HC trap may form coke molecules having a relatively low combustion temperature, such as below 500 C.

Hydrocarbon (HC) traps are disclosed. The HC trap may include a first zeolite material having an average pore diameter of at least 5.0 angstroms and configured to trap hydrocarbons from an exhaust stream and to release at least a portion of the trapped hydrocarbons at a temperature of at least 225 C. The HC trap may also include a second zeolite material having an average pore diameter of less than 5.0 angstroms or larger than 7.0 angstroms. One or both of the zeolite materials may include metal ions, such as transition, Group 1A, or platinum group metals. The HC trap may include two or more discrete layers of zeolite materials or the two or more zeolite materials may be mixed. The multiple zeolite HC trap may form coke molecules having a relatively low combustion temperature, such as below 500 C.

Method for the preparation of a metal-exchanged zeolites or mixtures of metal-exchanged zeolites, such as Cu-SSZ-13, Cu-ZSM-5, Cu-beta, or Fe-beta, comprising the steps of providing a dry mixture of a) one or more microporous zeotype materials that exhibit ion exchange capacity and b) one or more metal compounds; heating the mixture in a gaseous atmosphere containing ammonia to a temperature lower than 300? C. for a time sufficient to initiate and perform a solid state ion exchange of ions of the metal compound and ions of the zeolite material; and obtaining the metal-exchanged zeolite material.

Method for the preparation of a metal-exchanged zeolites or mixtures of metal-exchanged zeolites, such as Cu-SSZ-13, Cu-ZSM-5, Cu-beta, or Fe-beta, comprising the steps of providing a dry mixture of a) one or more microporous zeotype materials that exhibit ion exchange capacity and b) one or more metal compounds; heating the mixture in a gaseous atmosphere containing ammonia to a temperature lower than 300? C. for a time sufficient to initiate and perform a solid state ion exchange of ions of the metal compound and ions of the zeolite material; and obtaining the metal-exchanged zeolite material.

The invention proposes a method for the purification of exhaust gases which are generated by a diesel engine with a charging turbine, and a special device for carrying out said method. The device comprises, in the flow direction of the exhaust gas, a dosing device for a reducing agent from a reducing agent reservoir (2), an SCR catalytic converter (3), an oxidation catalytic converter (4) and a diesel particle filter (5). The system is particularly suitable for the purification of the exhaust gases of diesel vehicles in which engines with a turbocharger (charging turbine (1)) and an exhaust-gas recirculation device are used, which engines generate exhaust gases which, in addition to carbon monoxide, hydrocarbons and particles, have nitrogen oxides with an NO.sub.2/NO.sub.X ratio of between 0.3 and 0.7.

The invention relates to the production of aromatic hydrocarbon by the conversion of a feed comprising C.sub.2+ non-aromatic hydrocarbon, e.g., natural gas. The invention is particularly useful in converting natural gas to liquid-phase aromatic hydrocarbon, which can be more easily transported away from remote natural gas production facilities. The conversion is carried out in the presence of a dehydrocyclization catalyst comprising dehydrogenation and molecular sieve components. The dehydrocyclization catalyst has an average residence time of 90 seconds or less.

Disclosed is a catalyst composition and its use in a process for the conversion of a feedstock containing C.sub.8+ aromatic hydrocarbons to produce light aromatic products, comprising benzene, toluene and xylene. The catalyst composition comprises a mordenite zeolite synthesized from TEA or MTEA, optionally at least one first metal of Group 10 of the IUPAC Periodic Table, and optionally at least one second metal of Group 11 to 15 of the IUPAC Periodic Table, wherein said mordenite zeolite has a mesopore surface area of greater than 30 m.sup.2/g and said mordenite zeolite comprises agglomerates composed of primary crystallites, wherein said primary crystallites have an average primary crystal size as measured by TEM of less than 80 nm and an aspect ratio of less than 2.

Disclosed is a catalyst composition and its use in a process for the conversion of a feedstock containing C.sub.8+ aromatic hydrocarbons to produce light aromatic products, comprising benzene, toluene and xylene. The catalyst composition comprises a mordenite zeolite synthesized from TEA or MTEA, optionally at least one first metal of Group 10 of the IUPAC Periodic Table, and optionally at least one second metal of Group 11 to 15 of the IUPAC Periodic Table, wherein said mordenite zeolite has a mesopore surface area of greater than 30 m.sup.2/g and said mordenite zeolite comprises agglomerates composed of primary crystallites, wherein said primary crystallites have an average primary crystal size as measured by TEM of less than 80 nm and an aspect ratio of less than 2.

Disclosed are a catalyst system and its use in a process for the conversion of a feedstock containing C.sub.8+ aromatic hydrocarbons to produce light aromatic products, comprising benzene, toluene and xylene. The catalyst system comprises (a) a first catalyst bed comprising a first catalyst composition, said first catalyst composition comprising a zeolite having a constraint index of 3 to 12 combined (i) optionally with at least one first metal of Group 10 of the IUPAC Periodic Table, and (ii) optionally with at least one second metal of Group 11 to 15 of the IUPAC Periodic Table; and (b) a second catalyst bed comprising a second catalyst composition, said second catalyst composition comprising (i) a meso-mordenite zeolite, combined (ii) optionally with at least one first metal of Group 10 of the IUPAC Periodic Table, and (iii) optionally with at least one second metal of Group 11 to 15 of the IUPAC Periodic Table, wherein said meso-mordenite zeolite is synthesized from TEA or MTEA and having a mesopore surface area of greater than 30 m.sup.2/g and said meso-mordenite zeolite comprises agglomerates composed of primary crystallites, wherein said primary crystallites have an average primary crystal size as measured by TEM of less than 80 nm and an aspect ratio of less than 2.