Catalyst for catalyzing alkane dehydrogenation to synthesize olefin as well as preparation method and application of catalyst

Abstract

The invention belongs to the technical field of catalysts, and particularly relates to a catalyst for catalyzing alkane dehydrogenation to synthesize olefin as well as a preparation method and application thereof. According to the hair style, the MWW molecular sieve is used as a carrier, and a hydroxyl structure is increased by regulating and controlling the layered structure; then fixing Ti by using hydroxyl groups on the surface through an atom in-situ transplantation method; the preparation method comprises the following steps: fixing Au nanoparticles on Ti of a molecular sieve through a deposition-precipitation method, and preparing the supported Au catalyst of which the MWW structure supports Au particles with the size of 1-2nm by utilizing the pore structure of the MWW molecular sieve, especially the size of the Au particles limited by 2nm mesopores in an MCM-36 structure.

Description

technical field [0001] The invention belongs to the technical field of catalysts, and in particular relates to a catalyst for catalyzing alkane dehydrogenation to synthesize alkene and a preparation method and application thereof. Background technique [0002] Ethylene and propylene are important chemical raw materials, and also the basis of many chemicals such as styrene, polyethylene, ethylene oxide, polypropylene, acetone, etc., and one of the standards for measuring the level of a country's industrial development. The traditional production of low-carbon olefins mainly comes from the cracking process of naphtha or light oil, but due to the shortage of oil supply in my country, these production processes have been difficult to meet the requirements of the market. [0003] For a long time, the industrial production of ethylene is mainly realized by the steam cracking of ethane. Because of the strong endothermic reaction, the reaction temperature is required to be above 850...

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Problems solved by technology

The catalyst for the Oleflex process is Pt-Sn / Al 2 o 3 Catalyst, this process has the advantages of continuous reaction, no need for catalyst regeneration, and steady-state operation; however, side reactions and carbon deposition continue to occur, the catalyst life is short, and it is easy to deactivate

For the Catofin process, it uses Cr 2 o 3 / Al 2 o 3 Catalyst, the process needs to add steam and oxygen, steam can reduce the partial pressure of the reactant, accelerate conversion; patent CN1216686 also reported a chromium catalyst, that is, nano-Cr 2 o 3 Catalyst, this catalyst has a very high ethane conversion rate at 500-700 ° C, reaching more than 77%; however, due to the environmental pollution problems of chromium-based catalysts, it does not meet the requirements of sustainable development, chromium oxide-based Catalyst development has been limited

Patent CN106944080 reports a composite metal oxide catalyst, the active component of which is Mo-V-Ni / Ce, and the carrier is one of alumina, silica, and HZSM-5. The reaction is at 400-600 °C, The conversion rate of the catalyst is high, reaching 30-55%, but its ethylene selectivity is only 30-56%, and there are many carbon oxides in the product

Nakagawa which will load Ga 2 o 3 TiO 2 Catalyst, showing good activity in the oxidative dehydrogenation of ethane, but its disadvantage is that the stability of the catalyst is poor, and the selectivity of ethylene is low [Catalysis Letters,2000,64(2):215-221]

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