Catalyst for producing unsaturated aromatic hydrocarbon by dehydrogenating saturated aromatic hydrocarbon and application of catalyst

Abstract

The invention discloses a catalyst for producing unsaturated aromatic hydrocarbon by dehydrogenation of saturated aromatic hydrocarbon, which comprises an inert core and a shell layer wrapping the core, and the shell layer comprises a platinum metal active component, a silicon-aluminum molecular sieve and inert alumina with a specific surface area of less than 10m < 2 > / g; wherein the platinum-based metal active component is only combined with the silicon-aluminum molecular sieve, and the particle size of the platinum-based metal active component is less than 5nm, so that the problem that the catalytic activity is reduced due to grain growth after the platinum-based metal active component in the shell layer is used for a long time in the prior art is mainly solved.

Description

technical field [0001] The invention belongs to the technical field of catalysts, and in particular relates to a (thin shell type) catalyst which can be used for dehydrogenating saturated aromatic hydrocarbons to produce unsaturated aromatic hydrocarbons. Background technique [0002] Styrene is an important basic organic chemical raw material widely used in the production of plastics, rubber and resins. Catalytic dehydrogenation of ethylbenzene is the most important method for the production of styrene. The dehydrogenation of ethylbenzene to generate styrene and hydrogen is an endothermic reaction, so the bed temperature of the catalyst will decrease significantly during the reaction process, resulting in a decrease in the conversion rate of raw materials. Increasing the reaction temperature can increase the one-pass conversion of ethylbenzene, but it is still limited by thermodynamic equilibrium. A more effective way to control the reaction temperature is to introduce ox...

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Problems solved by technology

When the researchers studied the deactivation mechanism of the hydrogen selective oxidation catalyst (DOI: 10.3969 / j.issn.1001-7631.2006.02.006), they found that the main reason for the catalyst deactivation was that when the catalyst was exposed to high temperature and water vapor environment for a long time, the strong The hydrothermal effect will gradually agglomerate the grains of the active components, resulting in a decline in the performance of the catalyst

Patent CN1927455A adds additives such as tin oxide to the catalyst to hinder the aggregation of active components, but since the active components are loaded on the coating material through adsorption, the migration of active components cannot be completely avoided

[0006] Chinese patent CN101491758B reports a catalyst for the selective oxidation of hydrogen in the production of styrene. The catalyst uses an inner core of an inert carrier and an outer layer of a porous coating material bonded to the inner core to form a layered composite carrier, and in a layered composite The outer layer of the carrier is loaded with at least one platinum group metal selected from ruthenium, rhodium, palladium, osmium, iridium, platinum, at least one modifier selected from alkali metals and alkaline earth metals, and at least one selected from IVA compounds and At least one kind of lanthanide compound is used as a cocatalyst to solve the problems of low catalyst use efficiency, short life and high loss rate of raw materials. The catalyst element composition is complex, the manufacturing process is long, and the production cost is relatively high.

[0007] When the catalyst prepared by the above-mentioned patent is used for the selective oxidation of hydrogen, the particles of the active components of the catalyst will agglomerate and grow in particle size during long-term use, making it difficult to maintain long-term stability, which affects its long-term operation in the industrial process; maintaining a high It is more important to reduce the loss rate of aromatics in raw materials, especially in the case of increasingly tight resources and energy; at the same time, reducing catalyst manufacturing processes and reducing costs is also an important aspect

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