CN112657545A

CN112657545A - Olefin removal catalyst and preparation method and application thereof

Info

Publication number: CN112657545A
Application number: CN201910977188.8A
Authority: CN
Inventors: 周亚新; 孔德金; 郑均林; 李为; 王月梅
Original assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Current assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Priority date: 2019-10-15
Filing date: 2019-10-15
Publication date: 2021-04-16
Anticipated expiration: 2039-10-15
Also published as: CN112657545B

Abstract

The invention provides a de-olefin catalyst and a preparation method and application thereof, wherein the main component of the de-olefin catalyst comprises a Y/ZSM-5 intergrowth molecular sieve, and the ratio of the L acid amount to the B acid amount of the catalyst is (0.5-5) by utilizing the pyridine infrared desorption result at 200 ℃: 1. during preparation, the Y/ZSM-5 intergrowth molecular sieve is soaked in silica sol, and the preparation method is simple and easy to carry out. Meanwhile, the olefin removal catalyst has the characteristics of reasonable pore distribution, moderate surface acidity, proper acidity distribution and high reaction stability, and simultaneously, the characteristic of good regeneration stability is obtained by utilizing the characteristic of good structural stability of the ZSM-5 molecular sieve under the regeneration condition.

Description

Olefin removal catalyst and preparation method and application thereof

Technical Field

The invention relates to the technical field of catalytic olefin removal, in particular to a catalyst for olefin removal and a preparation method and application thereof.

Background

Aromatics are a basic feedstock for the petrochemical industry, and are derived primarily from aromatics complexes. The aromatic hydrocarbon products after catalytic reforming reaction all contain a certain amount of olefin impurities. The olefin is active in property, not only is easy to polymerize to form colloid, but also can react with other components to generate non-ideal components, thereby greatly influencing the quality of aromatic hydrocarbon products. On the other hand, certain petrochemical processes, such as xylene adsorption separation processes, are particularly sensitive to olefins and can be very adversely affected even if the olefin impurities are present in the order of parts per million. In order to obtain qualified chemical raw materials and ensure the smooth proceeding of subsequent processes, refining processes are carried out after reforming, aromatic hydrocarbon extraction, isomerization and toluene disproportionation processes to remove trace olefin impurities.

The xylene isomerization unit is an important component of an aromatic hydrocarbon integrated unit and is also the most important unit for producing PX in the aromatic hydrocarbon integrated unit, and the main function of the xylene isomerization unit is to convert C into C₈The basic process for converting mixed aromatics to the most commercially desirable para-xylene (PX) is to convert C₈After PX in the mixed aromatic hydrocarbon is separated by the adsorption separation unit, the PX-poor raw material is subjected to isomerization reaction to reestablish chemical equilibrium, and a product for realizing the rebalance of the xylene isomers is continuously sent to the adsorption separation device.

The argil has an acid center, so that trace olefin contained in the reformate can be subjected to reactions such as alkylation, polymerization and the like to generate high-boiling-point compounds, and then the high-boiling-point compounds are adsorbed by the argil or removed in a subsequent separation process.

Olefin in the isomerization reaction product is removed by a clay refining route, so that the requirement that the bromine index of the adsorption separation feeding material is lower than 20mgBr/100g is met. However, the clay has low activity and short service life and needs to be replaced frequently, so that the clay consumption is very large, the labor intensity is high, and the long, stable and excellent operation of the device is restricted.

The exploitation of clay causes permanent environmental damage. In addition, the deactivated argil containing aromatic hydrocarbon is very harmful to human health, cannot be recycled and can only be treated by landfill, so that serious secondary pollution is caused to the environment. Today, the environmental awareness is continuously strengthened, the problem is more and more concerned by the nation and the people, and the production enterprises urgently need catalytic olefin removal technology capable of solving the problems.

At present, the olefin removing catalyst is more commonly used by Y molecular sieve. The activity of the Y-type molecular sieve is more than 5 times of that of the carclazyte, and the service life is longer. This is because the molecular sieve has small pore passages and the oil-gas diffusion coefficient is generally 10^-11cm²Less than s, and a diffusion coefficient of generally 10 in the liquid phase^-1cm²On the order of/s, the influence of molecular diffusion during the reaction process is much greater than that of clay. In the aspect of the pore structure of the molecular sieve, the Y molecular sieve has a super cage, the average effective diameter of the super cage is 1.18nm and is far larger than the diameter of a main pore passage of the super cage by 0.74nm, linear chain macromolecules with smaller molecular diameter can be generated, larger molecules with the diameter of 0.74-1.18nm can also be generated, and the abundant and open pore structure ensures the larger pore volume of the molecular sieve, so that the stronger carbon capacity of the molecular sieve is ensured, and the service life of the molecular sieve catalyst is prolonged. However, the regeneration stability of the Y molecular sieve is not good, and the Y molecular sieve having a low silica-alumina ratio is more likely to collapse the framework structure and the pore structure.

Jiawei et al applied Y/ZSM-5 molecular sieve to butane cracking and aromatization reaction, found that at 650 deg.C, selectivity of ethylene and propylene reached 40.72%, and selectivity of benzene and toluene reached 27.46% [ synthesizing Y/ZSM-5 composite molecular sieve using ethylenediamine as template agent, petrochemical, 35(9):832](ii) a CN101190862A application of synthesized Y/ZSM-5 intergrowth molecular sieve to C₄-C₁₀The naphtha of hydrocarbon is used as raw material for preparing olefin by catalytic cracking, and the yield of ethylene and propylene is about 45%; CN104549467A reports a method for in-situ synthesis of a Y/ZSM-5 molecular sieve catalyst and application thereofCatalytically cracking naphtha to prepare ethylene and propylene.

In the aspect of catalytic olefin removal reaction, most of catalysts related in the prior art are unreasonably controlled in acid amount, and the method is characterized in that the strong acid amount is too much, the catalysts are easy to deposit carbon and accelerate inactivation, the side reaction degree of xylene is aggravated, and the xylene loss is increased; secondly, the method is characterized in that the removal rate of olefin is not high and the product quality is unqualified if the amount of the strong acid is too small, so that the subsequent process is influenced.

Disclosure of Invention

Aiming at the problem that the prior Y molecular sieve olefin removal catalyst has poor regeneration stability and causes lower total service life, the invention provides a novel olefin removal catalyst, wherein the L acid amount and the B acid amount have proper ranges, the reaction stability is high, and meanwhile, the characteristic of good regeneration stability is obtained by utilizing the characteristic of good structural stability under the condition of ZSM-5 molecular sieve regeneration.

The invention aims to provide a catalyst for removing olefin, which comprises Y/ZSM-5 intergrowth molecular sieve, wherein the ratio of the L acid amount to the B acid amount in the catalyst is (0.5-5) by utilizing the pyridine infrared desorption result at 200 ℃:1, preferably (1.1 to 3): 1.

the L acid and the B acid in the invention refer to the L acid and the B acid on a molecular sieve informed by a person skilled in the art, wherein the L acid refers to a Lewis acid, and the B acid refers to a Bronsted acid.

Wherein, only the molecular sieves with partially overlapped crystallization regions can coexist, and the ZSM-5 and Y molecular sieves in the Y/ZSM-5 coexisting molecular sieve used in the invention have the same crystal faces, so that the two different molecular sieves share the crystal faces, but have different silicon-aluminum ratios. In the processes of water vapor treatment and acid solution exchange, the Y molecular sieve with low silica-alumina ratio is easy to collapse in the framework structure and the pore structure, and ZSM-5 with symbiotic crystal faces is more stable, so that the Y molecular sieve has a stable structure. Meanwhile, the surface of the Y/ZSM-5 intergrowth molecular sieve is coated with silicon dioxide, so that the framework can be prevented from being excessively damaged in the steam treatment process, and silicon can be promoted to migrate into the framework during the ultra-stable dealumination, thereby improving the stability of the framework.

In a preferred embodiment, the mass ratio of the Y molecular sieve to the ZSM-5 molecular sieve is (1-20): 1, preferably (4-12): 1.

also, in the present invention, NH is passed₃The TPD results show that the Y/ZSM-5 intergrown molecular sieve has a small number of strong acid centers, a large number of weak acid centers and a large total acid amount compared to the Y molecular sieve. Thus, the Y/ZSM-5 intergrowth molecular sieve is more suitable for xylene dealkenation.

Wherein, the acidity distribution of the catalyst has great influence on the olefin removal reaction performance. The strong acid is excessive, the catalyst is easy to deposit carbon, the inactivation is accelerated, the side reaction degree of the dimethylbenzene is aggravated, and the loss of the dimethylbenzene is increased; if the amount of the strong acid is too small, the removal of aluminum from olefin is not high, the product quality is unqualified, and the subsequent process is influenced. Therefore, the xylene dealkening molecular sieve catalyst should have a suitable range of L acid amount and B acid amount.

In a preferred embodiment, the fresh catalyst crystallinity is 100% and the regenerated catalyst crystallinity is greater than 80% by XRD crystallinity.

The fresh catalyst refers to the catalyst of the invention which is put into use for the first time, and the regenerated catalyst refers to the catalyst which is obtained by using the deactivated catalyst and then regenerating the deactivated catalyst.

The regenerated catalyst refers to a catalyst obtained by regenerating the catalyst of the invention after being deactivated by a regeneration method which is common in the field; the general regeneration method may be to calcine the deactivated catalyst in an air atmosphere, preferably at 500 to 600 ℃ for 1 to 5 hours in an air atmosphere. The regeneration conditions for evaluation of the crystallinity of the catalyst after the catalyst of the present invention is regenerated may be calcination at 500 ℃ for 4 hours in an air atmosphere.

The second purpose of the invention is to provide a preparation method of the catalyst, which comprises the steps of dipping the Y/ZSM-5 intergrowth molecular sieve into silica sol, and then molding and roasting to obtain the catalyst.

In a preferred embodiment, the preparation method comprises the following steps:

step 1, dipping a Y/ZSM-5 intergrowth molecular sieve into silica sol;

and 2, forming and roasting the impregnated product and components including the binder to obtain the catalyst for removing olefin.

The Y/ZSM-5 intergrown molecular sieve may be prepared by methods disclosed in the prior art or may be purchased directly.

The shaping method of step 2 can adopt the shaping method which is common in the field of catalysts, such as the shaping method of mixing the components and extruding into strips, rolling balls or oil columns, and the like.

In a preferred embodiment, the silica sol has a mass concentration of 5 to 40%, preferably 5 to 30%.

In a preferred embodiment, the silica sol is used in an amount of 25 to 2000 parts by weight, preferably 75 to 1000 parts by weight, based on 100 parts by weight of the Y/ZSM-5 intergrown molecular sieve.

In a preferred embodiment, the temperature of the calcination is 400 to 600 ℃, preferably 500 to 600 ℃.

In a preferred embodiment, the calcination time is 0.5 to 5 hours, preferably 1 to 3 hours.

In a preferred embodiment, the Y/ZSM-5 intergrown molecular sieve impregnated with silica sol in step 1 is subjected to post-treatment including drying, pulverization, steam treatment and acid solution exchange treatment to obtain the impregnated product in step 2.

The Y/ZSM-5 intergrowth molecular sieve is pretreated by adopting the silica sol, and a layer of amorphous silica is formed on the surface, so that the excessive damage of a water vapor treatment process to the framework can be prevented, and the silicon can be promoted to migrate into the framework during the ultra-stable dealumination, thereby improving the stability of the framework.

In a further preferred embodiment, the steam treatment is carried out at 400 to 800 ℃ for 0.5 to 5 hours, preferably 450 to 700 ℃ for 1 to 3 hours.

In a further preferred embodiment, the acid solution exchange treatment is performed at 75-95 ℃ for 2-4 h, preferably 80-90 ℃ for 2-3 h.

In a preferred embodiment, the acid solution is an aqueous solution of at least one of hydrochloric acid, sulfuric acid, nitric acid, formic acid, acetic acid, propionic acid, oxalic acid, citric acid, and benzoic acid, preferably an aqueous solution of at least one of hydrochloric acid, oxalic acid, and citric acid.

In a further preferred embodiment, the acid solution has a weight concentration of 1 to 10%, preferably 4 to 8%.

In the preparation process of the catalyst, the Y/ZSM-5 intergrowth molecular sieve is directly treated by water vapor after being dipped and dried in silica sol so as to achieve the aim of improving the hydrothermal stability of the catalyst.

Wherein, in the processes of steam treatment and acid treatment, the silicon dioxide in the impregnated product is partially lost, so that the content of the silicon dioxide in the final product of the catalyst is low or almost zero.

In a preferred embodiment, the roasting in step 2 is optionally dried, preferably at 80-120 ℃.

The third object of the present invention is to provide the catalyst obtained by the preparation method of the second object of the present invention, wherein the ratio of the amount of L acid to the amount of B acid in the catalyst is (0.5-5): 1, preferably (1.1 to 3): 1;

preferably, the crystallinity of the fresh catalyst is 100 percent and the crystallinity of the regenerated catalyst is more than 80 percent by XRD crystallinity;

preferably, the mass ratio of the Y molecular sieve to the ZSM-5 molecular sieve is (1-20): 1, preferably (4-12): 1.

it is a fourth object of the present invention to provide the use of a catalyst according to one of the objects of the present invention or a catalyst according to a third of the objects of the present invention for the deolefination of aromatic hydrocarbons, including the deolefination of xylenes and the deolefination of reformate.

To date, no document has reported the use of Y/ZSM-5 intergrowth molecular sieves in aromatics deolefination reactions. In the reaction, the Y/ZSM-5 intergrowth molecular sieve catalyst has better reaction stability and regeneration repeatability than the Y molecular sieve catalyst.

The fifth purpose of the invention is to provide a method for removing olefin from aromatic hydrocarbonA process comprising contacting an aromatic hydrocarbon feedstock with a catalyst according to one or more of the objects of the present invention to effect a deolefination reaction. Wherein, when the arene olefin removal is xylene olefin removal, the raw material mainly comprises C₈Mixing aromatic hydrocarbons; when the aromatic hydrocarbon is subjected to olefin removal to obtain reformate olefin removal, the raw material mainly comprises 40-60% of C₈Mixing aromatic hydrocarbons, and non-aromatic hydrocarbons, benzene, toluene and C₉Aromatic hydrocarbon, C₁₀ ⁺Aromatic hydrocarbons, and the like.

In the invention, the reaction temperature is 140-250 ℃, the reaction pressure is 1.0-3.0 MPa, and the liquid phase mass space velocity is 1h^-1-10h^-1。

Liquid phase mass space velocity of xylene dealkening on industrial device is 4h^-1-10h^-1Liquid phase mass space velocity of 1h for olefin removal of reformate^-1-2h^-1. However, in order to examine the catalyst performance in a short time, the method of accelerated deactivation at a higher space velocity was used in the examples and comparative examples of the present invention.

Compared with the prior art, the invention has the following beneficial effects:

(1) the catalyst has the advantages of moderate surface acidity, proper acidity distribution, high reaction stability and the like;

(2) the characteristic of good regeneration stability is obtained by utilizing the characteristic of good structural stability of the ZSM-5 molecular sieve under the regeneration condition;

(3) the method greatly simplifies the pretreatment conditions, and after the symbiotic molecular sieve is impregnated by silica sol, a layer of amorphous silica is formed on the surface of the symbiotic molecular sieve, so that the excessive damage of the water vapor treatment process to the framework can be prevented, and the silicon can be promoted to migrate into the framework during the ultra-stable dealumination, thereby improving the stability of the framework.

Detailed Description

While the present invention will be described in detail with reference to the following examples, it should be understood that the following examples are illustrative of the present invention and are not to be construed as limiting the scope of the present invention.

In the examples, the ratio of the amount of L acid to the amount of B acid in the catalyst was determined by pyridine absorption infrared spectroscopy. Taking a certain amount of the Y/ZSM-5 intergrowth molecular sieve dried at 120 ℃, soaking the Y/ZSM-5 intergrowth molecular sieve by using silica sol, filtering the impregnated Y/ZSM-5 intergrowth molecular sieve, drying the impregnated Y/ZSM-5 intergrowth molecular sieve again at 120 ℃, and determining the content of the silica and the content of the intergrowth molecular sieve according to the weight change.

The Y/ZSM-5 intergrowth molecular sieve mainly uses the Y molecular sieve, so that a unimodal method is used for measuring the relative crystallinity of the Y molecular sieve in the catalyst when the crystallinity is calculated. The diffraction intensity of the catalyst is determined by the method of the literature [ study of the change rule of crystallinity of hydrothermal dealuminized USY molecular sieve, petroleum refining and chemical engineering, 28(3):16] and the peak height of diffraction peak of crystal face of Y molecular sieve 533. half-height width of the peak ].

Example 1

Dissolving 10g of glucose in 60mL of distilled water, adding 10g Y molecular sieve to uniformly disperse, transferring into a 100mL stainless steel reaction kettle, putting into a constant-temperature oven at 180 ℃ for 6h, filtering, drying, and repeating the operation for 3 times to obtain the carbon-modified Y molecular sieve. At room temperature, according to the quantity ratio nNaCl: nNa of the substances₂O∶nSiO₂∶nAl₂O₃∶nTPABr∶nH₂SO₄∶nH₂And preparing gel with O as 15: 6.2: 65: 1: 5.2: 4.1: 1000. Adding the carbon modified Y molecular sieve, stirring uniformly, and then putting into a constant-temperature oven at 75 ℃ for drying to obtain the dry glue.

10mL of 15% ethylenediamine solution is placed at the bottom of a 100mL stainless steel reaction kettle, dry glue is placed above the liquid and crystallized at 180 ℃ for 2d, and the Na-Y/ZSM-5 molecular sieve is obtained after washing, filtering, drying and roasting, wherein the content of the Y molecular sieve is 75% and the content of the ZSM-5 is 25%.

The molecular sieve is dried at 120 ℃, 10g of the molecular sieve is taken, the molecular sieve is soaked in 20g of silica sol with the mass fraction of 30% for 2 hours at room temperature, dried and crushed at 100 ℃, the content of silica on the surface of the molecular sieve is 3% according to the weight change, the molecular sieve is treated in water vapor at 500 ℃ for 3 hours, citric acid solution (10 wt%) at 90 ℃ is exchanged for 2 hours, then the molecular sieve is dried and crushed at 120 ℃, water, alumina binder, sesbania powder is added for extrusion molding, drying is carried out at 80 ℃, roasting is carried out at 550 ℃ to obtain the Y/ZSM-5 intergrowth molecular sieve catalyst, the desorption result of pyridine at 200 ℃ is measured, and the ratio of the L acid content to the B acid content in the catalyst is 1..

Crushing the Y/ZSM-5 catalyst, and taking 5g of particles with 20-40 meshes to perform a xylene non-hydrodeolefin test in a fixed bed reactor. The starting material was xylene isomerate and the bromine index was 200 mg Br per 100g of oil. Reaction pressure: 2.0MPa, temperature: 160 ℃, space velocity: at 20.0 time^-1The catalyst is deactivated after 360h reaction, with the outlet bromine index of 20mg Br/100g oil as standard.

The deactivated catalyst is roasted for 4 hours at 500 ℃ in air atmosphere to obtain a regenerated catalyst, and XRD results show that the crystallinity retention rate of the deactivated catalyst reaches 93.3 percent relative to that of a fresh catalyst, which indicates that the regeneration stability is good.

Example 2

Dissolving 10g of glucose in 60mL of distilled water, adding 10g Y molecular sieve to uniformly disperse, transferring into a 100mL stainless steel reaction kettle, putting into a constant-temperature oven at 180 ℃ for 6h, filtering, drying, and repeating the operation for 3 times to obtain the carbon-modified Y molecular sieve. At room temperature, according to the quantity ratio nNaCl: nNa of the substances₂O∶nSiO₂∶nAl₂O₃∶nTPABr∶nH₂SO₄∶nH₂And (3) preparing gel by using O as 8: 5.8: 98: 1: 6: 3.2: 700. Adding the carbon modified Y molecular sieve, stirring uniformly, and then putting into a constant-temperature oven at 75 ℃ for drying to obtain the dry glue.

And (2) placing 12mL of 20% ethylenediamine solution at the bottom of a 100mL stainless steel reaction kettle, placing the dry glue above the liquid, crystallizing at 180 ℃ for 3d, and washing, filtering, drying and roasting to obtain the Na-Y/ZSM-5 molecular sieve, wherein the content of the Y molecular sieve is 50% and the content of the ZSM-5 is 50%.

The molecular sieve is dried at 120 ℃, 10g of the molecular sieve is taken, the molecular sieve is soaked in 35g of silica sol with the mass fraction of 5% for 3 hours at room temperature, dried and crushed at 120 ℃, the content of silica on the surface of the molecular sieve is 2% according to the weight change, the molecular sieve is treated in water vapor at 500 ℃ for 3 hours, an acetic acid solution (7 wt%) at 90 ℃ is exchanged for 2 hours, then the molecular sieve is dried and crushed at 120 ℃, water, an alumina binder, sesbania powder are added for extrusion molding, the molecular sieve is dried at 80 ℃ and roasted at 550 ℃ to obtain the Y/ZSM-5 intergrowth molecular sieve catalyst, the desorption result of pyridine at 200 ℃ is that the ratio of the acid content of L acid to the acid content of B acid in the catalyst.

Crushing the Y/ZSM-5 catalyst, and taking 5g of particles with 20-40 meshes to perform a xylene non-hydrodeolefin test in a fixed bed reactor. The starting material was xylene isomerate and the bromine index was 200 mg Br per 100g of oil. Reaction pressure: 2.0MPa, temperature: 160 ℃, space velocity: at 20.0 time^-1The catalyst was deactivated after 410h reaction, using an outlet bromine index of 20mg Br/100g oil as standard.

The deactivated catalyst is roasted for 4 hours at 500 ℃ in air atmosphere to obtain the regenerated catalyst, and XRD results show that the crystallinity retention rate of the deactivated catalyst reaches 94.7 percent relative to that of a fresh catalyst, which indicates that the regeneration stability is good.

Example 3

The synthesis method of Na-Y/ZSM-5 was the same as that of example 1, except that the gel ratio was changed to nNaCl: nNa₂O∶nSiO₂∶nAl₂O₃∶nTPABr∶nH₂SO₄∶nH₂O20: 7.6: 40: 1: 4.3: 4.8: 881, and crystallizing the dried gel at 180 ℃ for 2 d. The obtained Na-Y/ZSM-5 molecular sieve has the Y molecular sieve content of 90 percent and the ZSM-5 content of 10 percent.

The molecular sieve is dried at 120 ℃, 10g of the molecular sieve is taken, the molecular sieve is soaked in 40g of silica sol with the mass fraction of 15% for 3 hours at room temperature, dried and crushed at 120 ℃, the content of silicon dioxide on the surface of the molecular sieve is 6% according to the weight change, the molecular sieve is treated in water vapor at 700 ℃ for 1 hour, hydrochloric acid solution (4 wt%) at 90 ℃ is exchanged for 3 hours, then the molecular sieve is dried and crushed at 120 ℃, water, alumina binder, sesbania powder is added for extrusion molding, drying is carried out at 80 ℃, roasting is carried out at 550 ℃ to obtain the Y/ZSM-5 intergrowth molecular sieve catalyst, the desorption result of pyridine at 200 ℃ is measured, and the ratio of the L acid content and the B acid content in the catalyst is 0.

Crushing the Y/ZSM-5 catalyst, and taking 5g of particles with 20-40 meshes to perform a xylene non-hydrodeolefin test in a fixed bed reactor. The starting material was xylene isomerate and the bromine index was 200 mg Br per 100g of oil. Reaction pressure: 2.0MPa, temperature: 160 ℃, space velocity: at 20.0 time^-1The catalyst is deactivated after 290h of reaction by taking the outlet bromine index of 20mg Br/100g oil as a standard.

The deactivated catalyst is roasted for 4 hours at 500 ℃ in air atmosphere to obtain the regenerated catalyst, and XRD results show that the crystallinity retention rate of the deactivated catalyst reaches 82.8 percent relative to that of a fresh catalyst, which indicates that the regeneration stability is good.

Example 4

The Y/ZSM-5 catalyst prepared in example 1 was crushed and 5g of 20-40 mesh particles were taken for non-hydrodeolefination test of reformate in a fixed bed reactor. The raw material is the bottom material of a deheptanizer of reformate, and the bromine index is 1200 mg Br/100g oil. Reaction pressure: 2.0MPa, temperature: 160 ℃, space velocity: at 10.0 time^-1The catalyst was deactivated after 140h reaction, using an outlet bromine index of 200 mg Br/100g oil as standard.

The deactivated catalyst is roasted for 4 hours at 500 ℃ in air atmosphere to obtain a regenerated catalyst, and XRD results show that the crystallinity retention rate of the deactivated catalyst reaches 83.6 percent relative to that of a fresh catalyst, which indicates that the regeneration stability is good.

Example 5

The procedure of example 3 was repeated except that the Na-Y/ZSM-5 molecular sieve was prepared by crystallizing the dried gel at 180 ℃ for 2.5d, the Y molecular sieve content was 80% and the ZSM-5 content was 20%.

The molecular sieve is dried at 120 ℃, 10g of the molecular sieve is taken, dipped for 3 hours at room temperature by 7.5g of silica sol with the mass fraction of 40 percent, dried and crushed at 120 ℃, treated for 5 hours in water vapor at 400 ℃, exchanged for 2 hours by sulfuric acid solution (2wt percent) at 80 ℃, dried and crushed at 120 ℃, added with water, alumina binder and sesbania powder, extruded into strips, dried at 80 ℃ and roasted at 600 ℃ to obtain the Y/ZSM-5 intergrowth molecular sieve catalyst. The ratio of the amount of L acid to the amount of B acid in the catalyst was 1.36.

The deactivated catalyst is roasted for 4 hours at 500 ℃ in air atmosphere to obtain the regenerated catalyst, and XRD results show that the crystallinity retention rate of the deactivated catalyst reaches 86.6 percent relative to that of a fresh catalyst, which indicates that the regeneration stability is good.

Example 6

The procedure of example 2 was repeated except that the prepared Na-Y/ZSM-5 molecular sieve was prepared by crystallizing the dried gel at 180 ℃ for 1.5 days, the Y molecular sieve content was 60% and the ZSM-5 content was 40%.

The molecular sieve is dried at 120 ℃, 10g of the molecular sieve is taken, the molecular sieve is soaked in 100g of silica sol with the mass fraction of 5% for 3 hours at room temperature, dried and crushed at 120 ℃, treated in water vapor with the temperature of 450 ℃ for 2 hours, exchanged with citric acid solution (10 wt%) with the temperature of 75 ℃ for 4 hours, dried and crushed at 120 ℃, added with water, alumina binder and sesbania powder for extrusion molding, dried at 80 ℃ and roasted at 500 ℃ to obtain the Y/ZSM-5 intergrowth molecular sieve catalyst, and the ratio of the L acid content to the B acid content in the catalyst is 2.44.

The deactivated catalyst is roasted for 4 hours at 500 ℃ in air atmosphere to obtain the regenerated catalyst, and XRD results show that the crystallinity retention rate of the deactivated catalyst reaches 89.4 percent relative to that of a fresh catalyst, which indicates that the regeneration stability is good.

Comparative example 1

The Y/ZSM-5 molecular sieve, catalyst, was prepared as in example 1, except that the intergrown molecular sieve was not impregnated with silica sol, but was directly subjected to steam treatment. The ratio of the L acid amount to the B acid amount in the catalyst is 1.86 by using the pyridine infrared desorption result at 200 ℃.

Crushing the Y/ZSM-5 catalyst, and taking 5g of particles with 20-40 meshes to perform a xylene non-hydrodeolefin test in a fixed bed reactor. The starting material was xylene isomerate and the bromine index was 200 mg Br per 100g of oil. Reaction pressure: 2.0MPa, temperature: 160 ℃, space velocity: at 20.0 time^-1The catalyst is deactivated after 220h reaction by taking the outlet bromine index of 20mg Br/100g oil as a standard.

The deactivated catalyst is roasted for 4 hours at 500 ℃ in an air atmosphere to obtain a regenerated catalyst, and XRD results show that the crystallinity retention rate of the deactivated catalyst reaches 68.1 percent relative to that of a fresh catalyst, which indicates that the regeneration stability of the deactivated catalyst is poor.

Comparative example 2

Direct silica sol impregnation, steam treatment, acid exchange, catalyst preparation using the Y molecular sieve of example 1, etc. were the same as in example 1. The ratio of the L acid amount to the B acid amount in the catalyst is 0.31 by using the pyridine infrared desorption result at 200 ℃.

Crushing the Y catalyst, and taking 5g of particles with 20-40 meshes to perform a xylene non-hydrogenation olefin removal test in a fixed bed reactor. The starting material was xylene isomerate and the bromine index was 200 mg Br per 100g of oil.Reaction pressure: 2.0MPa, temperature: 160 ℃, space velocity: at 20.0 time^-1The catalyst is deactivated after 155h reaction by taking the outlet bromine index of 20mg Br/100g oil as a standard.

The deactivated catalyst is roasted for 4 hours at 500 ℃ in air atmosphere to obtain a regenerated catalyst, and XRD results show that the crystallinity retention rate of the deactivated catalyst reaches 50.5 percent relative to that of a fresh catalyst, which indicates that the regeneration stability of the deactivated catalyst is poor.

Comparative example 3

Crushing clay particles, and taking 5g of particles with 20-40 meshes to perform a xylene non-hydrogenation olefin removal test in a fixed bed reactor. The starting material was xylene isomerate and the bromine index was 200 mg Br per 100g of oil. Reaction pressure: 2.0MPa, temperature: 160 ℃, space velocity: at 20.0 time^-1The catalyst was deactivated after 25h reaction, using an outlet bromine index of 20mg Br/100g oil as standard.

The deactivated catalyst is roasted for 4 hours at 500 ℃ in an air atmosphere to obtain a regenerated catalyst, and XRD results show that the crystallinity retention rate of the deactivated catalyst is up to 12.1 percent relative to that of a fresh catalyst, which indicates that the deactivated clay cannot be regenerated.

Claims

1. A catalyst for removing olefin comprises Y/ZSM-5 intergrowth molecular sieve, and the ratio of the L acid amount to the B acid amount in the catalyst is (0.5-5) by utilizing the pyridine infrared desorption result at 200 ℃:1, preferably (1.1 to 3): 1.

2. the catalyst of claim 1 wherein the fresh catalyst crystallinity is 100% and the regenerated catalyst crystallinity is greater than 80% by XRD crystallinity.

3. The catalyst of claim 1 or 2, wherein the mass ratio of the Y molecular sieve to the ZSM-5 molecular sieve is (1-20): 1, preferably (4-12): 1.

4. a preparation method of the de-olefin catalyst of any one of claims 1 to 3, comprising the steps of dipping the Y/ZSM-5 intergrowth molecular sieve into silica sol, and then carrying out molding and roasting treatment.

5. The method of claim 4, comprising the steps of:

step 1, dipping a Y/ZSM-5 intergrowth molecular sieve into silica sol;

6. The production method according to claim 5,

the mass concentration of the silica sol is 5-40%, preferably 5-30%; and/or

The silica sol is used in an amount of 25 to 2000 parts by weight, preferably 75 to 1000 parts by weight, based on 100 parts by weight of the Y/ZSM-5 intergrown molecular sieve.

7. The production method according to claim 5,

the roasting temperature is 400-600 ℃, and preferably 500-600 ℃.

8. The preparation method according to any one of claims 5 to 7, characterized in that the Y/ZSM-5 intergrown molecular sieve impregnated with the silica sol in the step 1 is subjected to post-treatment including drying, pulverization, water vapor treatment and acid solution exchange treatment to obtain the impregnated product in the step 2;

preferably, the steam treatment is carried out at 400-800 ℃ for 0.5-5 h, preferably at 450-700 ℃ for 1-3 h; and/or

Preferably, the acid solution exchange treatment is carried out at 75-95 ℃ for 2-4 h, preferably at 80-90 ℃ for 2-3 h.

9. The catalyst obtained by the preparation method according to any one of claims 5 to 8, wherein the ratio of the amount of L acid to the amount of B acid in the catalyst is (0.5 to 5) as measured by pyridine infrared desorption at 200 ℃:1, preferably (1.1 to 3): 1;

10. use of a catalyst according to any one of claims 1 to 3 or a catalyst according to claim 9 in the deolefination of aromatics.

11. A method for removing olefin from aromatic hydrocarbon, which comprises contacting aromatic hydrocarbon raw material with the catalyst of any one of claims 1 to 3 or the catalyst of claim 9 for reaction;

preferably, the reaction temperature is 140-250 ℃, the reaction pressure is 1.0-3.0 MPa, and the liquid phase mass space velocity is 1h^-1-10h^-1。