The present invention provides a modified composite molecular sieve, and a preparation method and an application of the modified composite molecular sieve. The modified composite molecular sieve comprises SiO.sub.2 and a composite molecular sieve that comprises molecular sieve MCM-22 and crystalline molecular sieve selected from at least one of ZSM-22, ZSM-23 and ZSM-48, wherein, the molecular sieve MCM-22 covers around the crystalline molecular sieve. The present invention further provides a catalyst and an application of the catalyst. The catalyst comprises a carrier and a noble metal loaded on the carrier, wherein, the carrier comprises a modified composite molecular sieve that is the modified composite molecular sieve provided in the present invention or the modified composite molecular sieve obtained with the method provided in the present invention. The catalyst that utilizes the composite molecular sieve as a carrier not only can decrease the solidifying point of waxy raw oil, but also can improve the yield of liquid product, is especially applicable to the isomerization dewaxing process of lube distillate, and has an advantage of remarkably improving the viscosity index of lube base oil.

A method for preparing liquid fuel by direct conversion of syngas uses the syngas as reaction raw material and conducts a catalytic conversion reaction on a fixed bed or a moving bed. The catalyst is a composite catalyst formed by compounding component I and component II in a mechanical mixing mode. The active ingredient of the component I is a metal oxide, and the component II is at least one of zeolites with one-dimensional ten-membered ring porous channels; and a weight ratio of the active ingredient in the component I to that in the component II is 0.1-20. The reaction process has high product yield and selectivity. The selectivity for liquid fuel composed of C.sub.5-C.sub.11 can reach 50-80%. The selectivity for aromatic hydrocarbon is less than 40% in C.sub.5-C.sub.11, while the selectivity for methane side product is less than 15%.

Systems and methods are provided for modifying the composition of the conversion catalyst in a reactor for oxygenate conversion during conversion of an oxygenate feed to allow for adjustment of the slate of conversion products. The modification of the conversion catalyst can be performed by introducing a substantial portion (relative to the amount of catalyst inventory in the reaction system) of make-up catalyst having a distinct composition relative to the conversion catalyst in the reaction system. Introducing the distinct composition of make-up catalyst can modify the composition of the conversion catalyst in the reactor to allow for changes in the resulting product slate. By introducing the distinct catalyst composition, the conversion catalyst in the reactor can correspond to a different composition of catalyst than the overall average catalyst composition within the catalyst inventory in the reaction system.

A feed mixture comprising at least one C.sub.3 olefin and/or at least one C.sub.4 olefin may be contacted with a zeolite catalyst under oligomerization reaction conditions to form a product mixture comprising a plurality of olefin oligomers comprising C.sub.12 and/or C.sub.16 olefin oligomers having an average branching index, as measured by gas chromatography, of about 2.2 or less, such as about 1.3 to about 2.0. The olefin oligomers may be contacted with a syngas mixture comprising carbon monoxide and hydrogen in the presence of a hydroformylation catalyst to form a hydroformylation reaction product, which may be subsequently reduced to form a plurality of branched alcohols. The branched alcohols, in turn, may be converted into an amphiphilic compound, such as a plurality of branched alcohol sulfates.

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.

Systems and methods are provided for modifying the composition of the conversion catalyst in a reactor for oxygenate conversion during conversion of an oxygenate feed to allow for adjustment of the slate of conversion products. The modification of the conversion catalyst can be performed by introducing a substantial portion (relative to the amount of catalyst inventory in the reaction system) of make-up catalyst having a distinct composition relative to the conversion catalyst in the reaction system. Introducing the distinct composition of make-up catalyst can modify the composition of the conversion catalyst in the reactor to allow for changes in the resulting product slate. By introducing the distinct catalyst composition, the conversion catalyst in the reactor can correspond to a different composition of catalyst than the overall average catalyst composition within the catalyst inventory in the reaction system.

The invention relates to converting non-aromatic hydrocarbon in the presence of CO.sub.2 to produce aromatic hydrocarbon. CO.sub.2 methanation using molecular hydrogen produced during the aromatization increases aromatic hydrocarbon yield. The invention also relates to equipment and materials useful in such upgrading, to processes for carrying out such upgrading, and to the use of such processes for, e.g., natural gas upgrading.

The invention relates to the production of aromatic hydrocarbon by the conversion of a feed comprising saturated hydrocarbon. At least a portion of the saturated hydrocarbon is converted to olefinic hydrocarbon. Aromatic hydrocarbon is produced from at least a portion of the olefinic hydrocarbon using at least one dehydrocyclization catalyst comprising dehydrogenation and molecular sieve components.

The invention relates to converting non-aromatic hydrocarbon in the presence of CO.sub.2 to produce aromatic hydrocarbon. CO.sub.2 methanation using molecular hydrogen produced during the aromatization increases aromatic hydrocarbon yield. The invention also relates to equipment and materials useful in such upgrading, to processes for carrying out such upgrading, and to the use of such processes for, e.g., natural gas upgrading.

The invention relates to the production of aromatic hydrocarbon by the conversion of a feed comprising saturated hydrocarbon. At least a portion of the saturated hydrocarbon is converted to olefinic hydrocarbon. Aromatic hydrocarbon is produced from at least a portion of the olefinic hydrocarbon using at least one dehydrocyclization catalyst comprising dehydrogenation and molecular sieve components.