Butane isomerization catalyst and preparation method and application thereof

Abstract

Provided are a butane isomerization catalyst and a preparation method and application thereof. The butane isomerization catalyst is prepared from SiO2, Al2O3, Na2O, H2O and pyridine, wherein the molar ratio of SiO2 to Al2O3 ranges from 20 to 100, the molar ratio of Na2O3 to SiO2 ranges from 0.1 to 0.22, the molar ratio of H2O to SiO2 ranges from 20 to 33, and the molar ratio of pyridine to SiO2 ranges from 0.4 to 0.6. A mixture prepared from a silicon source, an aluminum source, a template agent pyridine, inorganic base and seed crystals accounting for 0 to 10 wt% of SiO2 is subjected to hydrothermal crystallization at the temperature of 140 DEG C to 190 DEG C to obtain a ZSM-35 molecular sieve; after a crystallization mother solution is filtered out, stirring is carried out according to the proportion that Al2O3 accounts for 5-30 wt% of a dry basis material, meanwhile, a sodium aluminate solution and an aluminum sulfate solution are added dropwise, and the pH value of the material is kept and controlled to range from 8.0 to 10.0; after filtering and dehydration, extrusion forming is carried out, and negative pressure calcining and curing are carried out for 0.1 h to 2 h at the temperature of 250 DEG C to 550 DEG C; hydrothermal exchange treatment is carried out with an ammonium salt solution till Na2O is smaller than 0.1 wt%; chloroplatinic acid dipping is carried out after drying, 0-0.05 wt% of platinum is loaded, negative pressure calcination and excitation are carried out for 0.5 h to 4 h at the temperature of 400 DEG C to 650 DEG C after drying, and the needed catalyst is obtained. The catalyst is suitable for the reaction of generating isobutene through normal butane isomerization, and the better product selectivity, conversion activity and active period are achieved.

Description

technical field [0001] The invention relates to a butene isomerization catalyst and its preparation method and application, more specifically to a ZSM-35 molecular sieve catalyst for preparing isobutene from n-butene isomerization, its preparation method and application. Background technique [0002] Industrial C4 hydrocarbons mainly include steam cracking C4 hydrocarbons in ethylene plants and C4 hydrocarbons in refineries, etc. C4 hydrocarbons in cracking plants and C4 hydrocarbons in refineries contain varying amounts of butadiene and n-butene (butene-1, Butene-2), isobutene, isobutane, n-butane, etc. These components are important chemical raw materials with a wide range of uses. Industrial carbon tetrahydrocarbons contain a large number of carbon tetraolefins with wide applications, among which isobutene is an extremely important organic chemical raw material. Whether or not isobutene can be fully utilized is the key to the comprehensive utilization of carbon tetrahydro...

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Problems solved by technology

CN1040560A uses silica-alumina gel as the silica-alumina source to synthesize ZSM-35, and CN101468809A uses kaolin to replace part of the silica-alumina source, but there are not many reports concerning the influence of silica-alumina source on the catalytic performance of molecular sieves

For example, CN10168884A prepared a eutectic molecular sieve of Magadiite and ZSM-35, and CN101003379A prepared a composite molecular sieve of ZSM-35 and MCM-22, which formed a multiple channel structure from the physical structure, but this kind of micropores stacked multiple channels structure, and failed to show effective improvement in diffusion performance in catalytic reactions, and because the preparation steps were complex and difficult to control, its practical value was limited

[0015] CN103769209A Utilizes the regeneration under the protection of inert gas to make the reactivity of the regenerated catalyst even better than that of the fresh catalyst, but this technology itself cannot be directly applied to the catalyst and in the catalyst preparation process, and a large amount of inert gas also increases the operating cost of the regeneration process

[0016] For the time being, there is no report on the prior art that involves effectively improving the diffusion properties of ZSM-35 molecular sieve butene-like isomerization catalysts, as well as the activity, product selectivity, and especially improving the short activity cycle

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