A kind of light alkane dehydrogenation catalyst and method for preparing light alkene

Abstract

The invention relates to a low-carbon alkane dehydrogenation catalyst and a method for preparing low-carbon olefins, which mainly realizes the efficient conversion of low-carbon alkanes into low-carbon olefins by regulating the active center for catalytic dehydrogenation and the active center for catalyzing the transfer and desorption of low-carbon olefins . The catalyst of the present invention is a composite catalyst with dual active centers, and elements with relatively excellent dehydrogenation properties, such as V, Ni, Fe, Y, Mo, Zr, Ta, W, Co, are used as the active centers for activating C-H; The main group element catalyst Ga is used as the active center for catalyzing the transfer desorption of light olefins. The dual active centers can not only achieve efficient dehydrogenation of light alkanes, but also effectively avoid excessive dehydrogenation and reduce the selectivity of light alkenes.

Description

technical field [0001] The invention relates to a low-carbon alkane dehydrogenation catalyst for catalyzing the dehydrogenation of low-carbon alkanes to produce low-carbon olefins and a method for preparing low-carbon olefins. Background technique [0002] Propylene is an important basic petrochemical raw material second only to ethylene, and is mainly used to produce basic organic raw materials such as polypropylene, acrylonitrile, propylene oxide, acrylic acid, cumene, and octyl alcohol. In recent years, with the recovery of the global economy, the demand for downstream products of propylene has shown rapid growth. Relevant data show that the world's propylene consumption is increasing year by year, but the existing production capacity is not up to the requirement. Especially for my country, the supply of propylene has been far below the actual demand, and the annual import of propylene is as high as several hundred tons. Therefore, the insufficient supply of raw material...

AI Technical Summary

Problems solved by technology

[0004] At present, there are two main types of propane dehydrogenation catalysts that have been commercialized, one is Pt-Sn catalyst, and the other is CrOx catalyst, but there are still huge challenges and room for improvement.

The catalyst disclosed in Chinese patent (CN200710025372.X) is a preparation method in which alumina-modified mesoporous molecular sieves are impregnated with platinum-tin components on the carrier, the conversion rate of propane is only 17%, and the selectivity of propylene is 93%; Chinese patent (CN200710023431 .X) adopt the hydrothermal synthesis method to introduce tin into the ZSM-5 molecular sieve carrier, and use the impregnation method to support the platinum component. After the catalyst runs for 100 hours, the propane conversion rate is higher than 30%, and the propylene selectivity is 99%, but the The patent does not provide stability data for the charcoal regeneration process

Chinese patents (CN200710020064.8) and (CN200710133324.2) disclose a platinum-tin catalyst for propane dehydrogenation reaction, which adopts the preparation method of co-impregnation of tin component and platinum component, and the carrier is Y type, ZSM-5 After 720 hours of continuous operation of the catalyst containing Na-containing molecular sieves, the conversion rate of propane is 30.5%, and the selectivity of propylene is 96.4%, but the activity drops by half after two charcoal regenerations

The catalyst disclosed in the Chinese patent (CN96117222.3) adopts the impregnation method to load Pt onto the MgAl(O) composite oxide carrier. The initial isobutane conversion rate of the catalyst is 59%, which drops to 45.6% after 5 hours of reaction, and the isobutene The selectivity is 97% to 98%, but the patent does not provide the stability data of the charcoal regeneration process

However, there are still huge challenges to achieve this goal. Therefore, traditional catalysts generally use the method of sacrificing the conversion rate of propane to improve the selectivity of propylene, such as using alkali metal Na or K to poison the acidic active sites in the catalyst.

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