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CN-121988335-A - Alkyl arene dehydrogenation catalyst and preparation method and application thereof

CN121988335ACN 121988335 ACN121988335 ACN 121988335ACN-121988335-A

Abstract

The invention discloses an alkyl aromatic hydrocarbon dehydrogenation catalyst and a preparation method and application thereof. The catalyst comprises iron, potassium, molybdenum, rare earth and metal auxiliaries, wherein the weight ratio (Ko/Ki) of the potassium component to the internal content of the catalyst is EDS =1.2-2.0. The catalyst is used in alkyl arene dehydrogenating reaction, and has the features of high initial activity and high stability.

Inventors

  • WEI CHUNLING
  • MIAO CHANGXI
  • SONG LEI
  • ZHANG ZHENGPAI
  • NI JUNPING

Assignees

  • 中国石油化工股份有限公司
  • 中石化（上海）石油化工研究院有限公司

Dates

Publication Date
20260508
Application Date
20241107

Claims (10)

  1. 1. An alkylaromatic hydrocarbon dehydrogenation catalyst comprises iron, potassium, molybdenum, rare earth and metal auxiliary agents, wherein the weight ratio (Ko/Ki) EDS =1.2-2.0, preferably 1.4-2.0, of potassium components on the surface of the catalyst to the content of the catalyst.
  2. 2. The catalyst according to claim 1, characterized in that it comprises, on a metal oxide basis, on a catalyst mass basis: 65-78 wt% of Fe 2 O 3 ; 7-17 wt% of K 2 O; 0.75-3.5% MoO 3 ; 8-15 wt% of rare earth oxide; 0.7-4.0 wt% of metal auxiliary oxide; Preferably, the metal auxiliary comprises at least one of alkaline earth metals, ti, mn, zn, cu.
  3. 3. The catalyst according to claim 1 or 2, wherein the rare earth comprises cerium and a rare earth L, the rare earth L being at least one selected from lanthanum, praseodymium and yttrium; preferably, the rare earth L accounts for 0.5-5 wt% of the weight of cerium in terms of oxide.
  4. 4. A method for preparing the catalyst according to any one of claims 1 to 3, comprising: (1) Mixing an iron source, a potassium source, a molybdenum source, a rare earth source and a metal auxiliary agent source with a pore-forming agent, performing forming treatment and roasting to obtain a precursor; (2) And (3) carrying out heat treatment on the precursor in the step (1) in water vapor to obtain the catalyst.
  5. 5. The method according to claim 4, wherein in the step (2), the heat treatment is performed at 550-600 ℃ for 0.5-4 hours, and/or the volume space velocity of water vapor is 0.5-1.5 h -1 .
  6. 6. The method according to claim 4 or 5, wherein in the step (2), the heat-treated atmosphere further contains hydrogen, and further, the hydrogen occupies 5-15% by volume of the water vapor.
  7. 7. The method of claim 4, wherein in step (1), the cerium source comprises a first cerium source and a second cerium source; preferably, firstly mixing an iron source, a potassium source, a molybdenum source, a first cerium source, a metal auxiliary source and a pore-forming agent, and then adding the rare earth L source and a second cerium source; Further preferably, the rare earth L source, the second cerium source and water are mixed and then mixed with other raw materials; and/or the mass ratio of the first cerium source to the second cerium source is 2:1-10:1, calculated as oxide.
  8. 8. The method according to claim 4, wherein in the step (1), the roasting condition is that the temperature is 350-650 ℃ and the time is 3-14 h; Further, the roasting is two-stage roasting, wherein the temperature of the first-stage roasting is 350-650 ℃ and the time is 3-8 hours, and the temperature of the second-stage roasting is 780-900 ℃ and the time is 3-6 hours.
  9. 9. Use of the catalyst of any one of claims 1 to 3 or the catalyst prepared by the method of any one of claims 4 to 8 in a reaction for preparing alkenyl arene by dehydrogenation of alkyl arene.
  10. 10. The use according to claim 9, wherein the reaction conditions comprise a reaction temperature of 590-640 ℃, a reaction pressure of 35 kPaA-normal pressure, a liquid hourly space velocity of 0.3-2 hours -1 , and a water ratio of 1.0-5.0 by weight.

Description

Alkyl arene dehydrogenation catalyst and preparation method and application thereof Technical Field The invention belongs to the field of alkyl arene dehydrogenation reaction, and particularly relates to an alkyl arene dehydrogenation catalyst, and a preparation method and application thereof. Background The research of the catalyst for preparing alkenyl arene by dehydrogenating alkyl arene starts from the 30 th century, and after decades of research and development of the catalyst, the iron-based catalyst taking Fe-K-Ce-Mo as a basic component is basically adopted at present. Styrene, one of the alkenyl arene products, is an important bulk basic organic raw material, mainly used for the production of synthetic resins and rubber. Based on the wide use of styrene, the world's styrene industry is rapidly evolving with 2022 production capacity exceeding 4400 ten thousand tons per year. Ethylbenzene catalytic dehydrogenation is always the dominant technical route for producing styrene, and the production capacity of the ethylbenzene catalytic dehydrogenation accounts for about 85% of the total production capacity of styrene. For the chemical catalytic process of preparing alkenyl arene by dehydrogenating alkyl arene, the catalyst plays a key role in the production process, and the economy of the dehydrogenation process is determined by the advantages and disadvantages of the catalyst. CN1298856a discloses an alkyl aromatic hydrocarbon dehydrogenation catalyst and a preparation method thereof. The catalyst takes Fe-K-Ce-Mo-Mg as a main system and takes at least one of metals in IB-VIIIB, IIIA-VA groups as an auxiliary agent. The catalyst has better self-regeneration capability. However, the prior art has little research on the initial activity and induction period of the catalyst. If the initial activity of the catalyst is high and the induction period is short, the activation time of the device during starting can be shortened, and the purposes of energy saving and efficiency improvement are achieved. With the great expansion of styrene productivity, market competition is aggravated, and how to further improve the production efficiency of the device and the economic benefit of enterprises is one of the concerns of researchers. In addition, for the production of other alkylaromatic products such as divinylbenzene, methylstyrene and the like, the initial activity of the dehydrogenation catalyst is required to be higher due to the larger molecules of the alkylaromatic raw material, so that the initial activity of the catalyst is also an important direction for developing the catalyst. Disclosure of Invention Aiming at the problem of insufficient initial activity of the catalyst in the prior art, the invention provides an alkyl aromatic hydrocarbon dehydrogenation catalyst and a preparation method and application thereof. The catalyst is used in alkyl arene dehydrogenating reaction, and has the features of high initial activity and high stability. In a first aspect, the present invention provides an alkylaromatic dehydrogenation catalyst. The catalyst comprises: Iron, potassium, molybdenum, rare earth and metal auxiliary agents, wherein the weight ratio (Ko/Ki) EDS =1.2-2.0, preferably 1.4-2.0, of the potassium component to the catalyst surface and the catalyst internal content. According to the present invention, (Ko/Ki) EDS may be any one of values 1.3, 1.35, 1.4, 1.45, 1.5, 1.55, 1.6, 1.65, 1.7, 1.75, 1.8, 1.85, 1.9, 1.95, as non-limiting examples. According to the invention, the catalyst further comprises, on a mass basis, the catalyst comprising, in terms of metal oxide: 65-78 wt% of Fe 2O3; 7-17 wt% of K 2 O; 0.75-3.5% MoO 3; 8-15 wt% of rare earth oxide; 0.7-4.0 wt% of metal auxiliary oxide. According to the invention, the rare earth comprises cerium and rare earth L. The rare earth L is at least one selected from lanthanum, praseodymium and yttrium. Wherein, the rare earth L (at least one selected from lanthanum, praseodymium and yttrium) accounts for 0.5wt% to 5wt% of the weight of cerium based on oxide. According to the invention, the metal auxiliary comprises at least one of alkaline earth metals, ti, mn, zn, cu. The second aspect of the invention provides a method for preparing the catalyst. The method comprises the following steps: (1) Mixing an iron source, a potassium source, a molybdenum source, a rare earth source and a metal auxiliary agent source with a pore-forming agent, performing forming treatment and roasting to obtain a precursor; (2) And (3) carrying out heat treatment on the precursor in the step (1) in water vapor to obtain the catalyst. According to the present invention, in step (1), the iron source includes at least one of iron oxide red, iron oxide yellow, and iron oxide black. The potassium source comprises at least one of potassium hydroxide, potassium carbonate and potassium nitrate. The molybdenum source comprises at least one of a salt and an oxide thereof. The rare earth source