阅读说明：本技术 一种高酸量改性y型分子筛及其制备方法与应用 (High-acid-content modified Y-type molecular sieve and preparation method and application thereof ) 是由 秦波 柳伟 杜艳泽 高杭 董立廷 于 2019-10-28 设计创作，主要内容包括：本发明公开一种高酸量的改性Y型分子筛的制备方法,具体包括如下内容：将氢型Y型分子筛加入到水溶液中,固液质量比为1:5～1:40,在搅拌的状态下升温至40～99℃,然后加入铝源和硅源,并继续恒温搅拌0.5～2.0小时,最后过滤、干燥并将干燥后的产品在水热处理装置中恒温二次晶化,得到高酸量的改性Y型分子筛。所述方法制备的分子筛具有更多的可接触的有效酸性位,有利于为大分子提供更多的反应空间和目的产物的选择性,提高了分子筛的催化效率,分子筛制备方法简单,适用于工业应用。(The invention discloses a preparation method of a modified Y-type molecular sieve with high acid content, which specifically comprises the following steps: adding a hydrogen type Y-shaped molecular sieve into an aqueous solution, wherein the solid-liquid mass ratio is 1: 5-1: 40, heating to 40-99 ℃ under the stirring state, adding an aluminum source and a silicon source, continuously stirring at a constant temperature for 0.5-2.0 hours, filtering, drying, and performing constant-temperature secondary crystallization on a dried product in a hydrothermal treatment device to obtain the high-acid-content modified Y-shaped molecular sieve. The molecular sieve prepared by the method has more accessible effective acid sites, is beneficial to providing more reaction spaces and selectivity of target products for macromolecules, improves the catalytic efficiency of the molecular sieve, is simple in preparation method, and is suitable for industrial application.)

1. A preparation method of a modified Y-type molecular sieve with high acid content is characterized by comprising the following steps: the method specifically comprises the following steps: adding a hydrogen type Y-shaped molecular sieve into an aqueous solution, wherein the solid-liquid mass ratio is 1: 5-1: 40, heating to 40-99 ℃ under the stirring state, adding an aluminum source and a silicon source, continuously stirring at a constant temperature for 0.5-2.0 hours, filtering, drying, and performing constant-temperature secondary crystallization on a dried product in a hydrothermal treatment device to obtain the high-acid-content modified Y-shaped molecular sieve.

2. The method of claim 1, wherein: the hydrogen type Y-shaped molecular sieve is a commercial product or is prepared by adopting the prior art, the molar ratio of silicon oxide to aluminum oxide is 4.6-90.0, and the specific surface area is 530-980 m²(ii)/g; the content of the sodium oxide is 0.02wt% -0.50 wt%.

3. The method of claim 1, wherein: the aluminum source is at least one of aluminum ethoxide, aluminum triethoxide, aluminum isopropoxide, aluminum sec-butoxide and aluminum n-butoxide, and the addition amount of the aluminum source accounts for 0.05-5.0% of the weight of the Y-type molecular sieve in terms of aluminum oxide.

4. The method of claim 1, wherein: the silicon source is low-sodium silica sol, wherein the content of silicon oxide is 5-35 wt%, the content of sodium oxide is 0.02-0.5 wt%, and the adding amount of the silicon source accounts for 5.0-25.0 wt% of the Y-type molecular sieve in terms of silicon oxide.

5. The method of claim 1, wherein: the secondary crystallization condition in the hydrothermal treatment device is that the hydrothermal crystallization is carried out for 0.5-24.0 hours at the constant temperature of 100-750 ℃ under the pressure of 0.05-0.50 MPa.

6. A high acid weight modified Y-type molecular sieve prepared by the process of any of claims 1 to 5, characterized in that: has the following properties: the molar ratio of the silicon oxide to the aluminum oxide is 6-50; the specific surface area is 580-1050 m²G,; the amount of acid is 0.120 to 1.550 mmol/g.

7. The molecular sieve of claim 6, characterized in that: the molar ratio of the silicon oxide to the aluminum oxide is 8-25; the specific surface area is 750 to 950m²(ii)/g; the amount of acid is 0.250 to 1.350 mmol/g.

8. The use of the high acid modified Y-type molecular sieve of claim 6 or 7 for the preparation of a hydrocracking catalyst having the following composition: the modified Y-type molecular sieve comprises 3-78% of components in percentage by weight; 3% -65% of alumina; the VIB group metal accounts for 5% -35% of oxides; the VIII group metal accounts for 1% -10% of the oxide; the group VIB metals are tungsten (W) and molybdenum (Mo), and the group VIII metals are cobalt (Co) and nickel (Ni).

9. Use according to claim 8, characterized in that: the modified Y-type molecular sieve comprises 10-65% of components; 5-50% of alumina; the VIB group metal accounts for 10-28% of oxides; the amount of the group VIII metal is 3-8% in terms of oxide.

10. The catalyst prepared by the application of the catalyst in the claim 8 or 9 is used for diesel oil hydrocracking, and the reaction conditions are as follows: under the condition of hydrogen existence, the reaction pressure is 3-20 MPa, the reaction temperature is 250-450 ℃, and the hydrogen oil bodyThe volume ratio is 500-1800, and the liquid hourly space velocity is 0.5-5.0 h^-1。

Technical Field

The invention relates to a high-acid-content modified Y-type molecular sieve, a preparation method and application thereof, in particular to a high-acid-content modified Y-type molecular sieve, a preparation method thereof and application thereof in a hydrocracking catalyst.

Background

The Y-type catalyst is formed by mutually communicating an octahedral molecular sieve cage along three crystal axis directions through a twelve-membered ring, is an excellent catalyst active component, and has high cracking activity and good selectivity. Therefore, the discovery and the use of the Y-type molecular sieve have epoch-making significance in the field of catalysis.

Because the Y-type molecular sieve with low silicon-aluminum ratio (the mole ratio of silicon oxide to aluminum oxide is 3-4.2) has no good hydrothermal stability, the Y-type molecular sieve has no extensive research and general attention in the actual synthesis process and application. The high silica alumina ratio Y-type molecular sieve (the mole ratio of silica to alumina is more than 4.3) has good hydrothermal stability and acid stability, and can play an irreplaceable role in the catalytic cracking, hydrocracking and other processes of petroleum processing as a catalytic material after being modified.

The modification work of the Y-type molecular sieve has been widely concerned by researchers. The modification research of the Y-type molecular sieve mainly comprises means such as ion exchange, heat treatment, hydrothermal treatment, acid or acid salt treatment, alkali or alkaline salt and complex treatment and the like. Through the treatment processes, the desilication and dealumination of the molecular sieve are realized, the stability of the molecular sieve is improved, a large number of secondary mesoporous structures are generated, a large number of generated secondary pores are beneficial to the reaction and diffusion of macromolecules, and the effective utilization rate of the acid sites of the molecular sieve is improved. The current main molecular sieve modification means is to combine and use the modification means, so that the use performance of the molecular sieve can be effectively improved. Generally, the Y-type molecular sieve is subjected to ion exchange, then to heat treatment or hydrothermal treatment, and finally to acid treatment, so that the molecular sieve is dealuminized, the hydrothermal stability is improved, and a large number of secondary pore structures can be generated. One method developed in recent years is to perform alkali treatment or alkaline salt treatment on the Y-shaped molecular sieve after acid treatment, and further perform alkali treatment after acid treatment, so that the amount of secondary pores can be greatly increased, and meanwhile, the acid amount of the molecular sieve can be increased, and the problem of insufficient acid amount caused by original advanced treatment is solved. The existing Y-type molecular sieve technology focuses on the adjustment of a pore channel structure, improves the diffusion performance of the molecular sieve by forming a large number of secondary pore structures in molecular sieve particles, and is realized in the actual reaction process, and the cracking function is the acid site of the molecular sieve. Therefore, the adjustment of the acidic site performance of the molecular sieve by the modification technology is an important research direction.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a modified Y-type molecular sieve with high acid content and a preparation method thereof. The molecular sieve has more accessible effective acid sites, is beneficial to providing more reaction spaces and selectivity of target products for macromolecules, improves the catalytic efficiency of the molecular sieve, has a simple preparation method, and is suitable for industrial application.

The invention relates to a preparation method of a modified Y-type molecular sieve with high acid content, which specifically comprises the following steps:

adding a hydrogen type Y-shaped molecular sieve into an aqueous solution, wherein the solid-liquid mass ratio is 1: 5-1: 40, heating to 40-99 ℃ under the stirring state, adding an aluminum source and a silicon source, continuously stirring at a constant temperature for 0.5-2.0 hours, filtering, drying, and performing constant-temperature secondary crystallization on a dried product in a hydrothermal treatment device to obtain the high-acid-content modified Y-shaped molecular sieve.

In the method, the hydrogen type Y-shaped molecular sieve is a commercial product or is prepared by adopting the prior art, the molar ratio of silicon oxide to aluminum oxide is 4.6-90.0, and the specific surface area is 530-980 m²(ii)/g; the content of the sodium oxide is 0.02wt% -0.50 wt%.

In the method, the aluminum source is easily hydrolyzed aluminum alkoxides, such as aluminum ethoxide, aluminum triethoxide, aluminum isopropoxide, aluminum sec-butoxide, aluminum n-butoxide and the like, and the addition amount of the aluminum source is 0.05-5.0% of the weight percentage of the Y-type molecular sieve (calculated as alumina).

In the method, the silicon source is low-sodium silica sol, wherein the content of silicon oxide is 5-35 wt%, the content of sodium oxide is 0.02-0.5 wt%, and the adding amount of the silicon source accounts for 5.0-25.0 wt% of the weight percentage (calculated by silicon oxide) of the Y-type molecular sieve.

In the method, the secondary crystallization condition in the hydrothermal treatment device is that the hydrothermal crystallization is carried out for 0.5-24.0 hours at the constant temperature of 100-750 ℃ under the pressure of 0.05-0.50 MPa.

The high-acid-content modified Y-type molecular sieve prepared by the method has the following properties: the molar ratio of the silicon oxide to the aluminum oxide is 6-50, preferably 8-25; the specific surface area is 580-1050 m²Per g, preferably 750 to 950m²(ii)/g; the amount of the acid is 0.120 to 1.550mmol/g, preferably 0.250 to 1.350 mmol/g.

The modified Y-type molecular sieve is used for preparing a hydrocracking catalyst, and the hydrocracking catalyst comprises the following components: the modified Y-type molecular sieve generally comprises 3-78 wt%, preferably 10-65 wt%; the content of the aluminum oxide is generally 3-65%, preferably 5-50%; the group VIB metal (calculated by oxide) is generally 5-35%, preferably 10-28%; the content of VIII group metal (calculated by oxide) is generally 1-10%, preferably 3-8%; the group VIB metals are preferably tungsten (W) and molybdenum (Mo), and the group VIII metals are preferably cobalt (Co) and nickel (Ni).

The catalyst is used for diesel oil hydrocracking, and the reaction conditions are as follows: in the presence of hydrogen, the reaction pressure is 3-20 MPa, the reaction temperature is 250-450 ℃, the volume ratio of hydrogen to oil is 500-1800, and the liquid hourly space velocity is 0.5-5.0 h^-1。

According to the method, the silicon-aluminum gel is introduced to the surface of the molecular sieve in the molecular sieve, and then the hydrothermal steam secondary crystallization technology of a low-sodium system is adopted, so that the silicon-aluminum gel on the surface of the molecular sieve is converted into a molecular sieve crystal structure with fully exposed acid sites, more acid sites with better accessibility are formed on the surface of the Y-type molecular sieve, and the accessibility of the active sites of the modified Y-type molecular sieve is greatly improved. The modified Y-type molecular sieve prepared by the method can be directly used as an acidic carrier for preparing a catalyst. Compared with the existing modification method, the method disclosed by the invention combines the advantages of the conventional molecular sieve post-treatment and hydrothermal crystallization technologies, and the pyridine infrared acid adsorption capacity of the prepared Y-type molecular sieve is improved by 5% -50% under the condition that the silica-alumina ratio is the same, so that the molecular sieve prepared by the method has higher catalytic efficiency, can preferentially convert condensed ring macromolecules in the hydrocracking process, and has a wide application prospect.

Drawings

Figure 1 is an XRD diffractogram of the Y-type molecular sieve prepared in example 1.

Detailed Description

The following examples further illustrate the preparation of the present invention, but are not to be construed as limiting the process of the present invention.

The preparation process adopts a hydrogen type Y-shaped molecular sieve, and has the following properties: the molar ratio of the silicon oxide to the aluminum oxide is 8.9, and the specific surface area is 787m²Per g, sodium oxide content 0.28 wt%.

Example 1

Adding a hydrogen type Y-shaped molecular sieve into an aqueous solution, wherein the solid-liquid mass ratio is 1:15, heating to 65 ℃ under the stirring state, then slowly adding aluminum ethoxide accounting for 0.5 percent of the weight percentage (calculated by alumina) of the Y-shaped molecular sieve, then adding silica sol accounting for 15.0 percent of the weight percentage (calculated by silica) of the Y-shaped molecular sieve, continuously stirring for 1.0 hour at constant temperature, then filtering, drying, and carrying out hydrothermal crystallization on the dried product at constant temperature of 250 ℃ under the pressure of 0.15MPa for 8.0 hours to obtain the modified Y-shaped molecular sieve with high acid content. Specific properties of the molecular sieve are shown in table 1.

Example 2

Adding a hydrogen type Y-shaped molecular sieve into an aqueous solution, wherein the solid-liquid mass ratio is 1:8, heating to 80 ℃ under the stirring state, then sequentially and slowly adding aluminum triethoxide accounting for 1.5 percent of the weight percentage (calculated by aluminum oxide) of the Y-shaped molecular sieve, then adding silica sol accounting for 18.0 percent of the weight percentage (calculated by silicon oxide) of the Y-shaped molecular sieve, continuously stirring for 1.5 hours at constant temperature, then filtering, drying, and carrying out hydrothermal crystallization on the dried product at constant temperature for 3.0 hours under the pressure of 0.20MPa and the temperature of 550 ℃ to obtain the modified Y-shaped molecular sieve with high acid content. Specific properties of the molecular sieve are shown in table 1.

Example 3

Adding a hydrogen type Y-shaped molecular sieve into an aqueous solution, wherein the solid-liquid mass ratio is 1:35, heating to 50 ℃ under the stirring state, then slowly adding aluminum isopropoxide accounting for 3.5 percent of the weight of the Y-shaped molecular sieve (calculated by alumina), then adding silica sol accounting for 24.0 percent of the weight of the Y-shaped molecular sieve (calculated by silica), continuously stirring for 2.0 hours at constant temperature, then filtering, drying, and carrying out hydrothermal crystallization on the dried product at constant temperature for 18 hours under the pressure of 0.35MPa and the temperature of 350 ℃ to obtain the modified Y-shaped molecular sieve with high acid content. Specific properties of the molecular sieve are shown in table 1.

Example 4

Adding a hydrogen type Y-shaped molecular sieve into an aqueous solution, wherein the solid-liquid mass ratio is 1:8, heating to 90 ℃ under the stirring state, then slowly adding aluminum sec-butoxide accounting for 2.2 percent of the weight of the Y-shaped molecular sieve (calculated by alumina), then adding silica sol accounting for 12.5 percent of the weight of the Y-shaped molecular sieve (calculated by silica), continuously stirring for 1.5 hours at constant temperature, then filtering, drying, and carrying out hydrothermal crystallization on the dried product at constant temperature of 300 ℃ under the pressure of 0.15MPa for 12 hours to obtain the modified Y-shaped molecular sieve with high acid content. Specific properties of the molecular sieve are shown in table 1.

Example 5

Adding a hydrogen type Y-shaped molecular sieve into an aqueous solution, wherein the solid-liquid mass ratio is 1:15, heating to 45 ℃ under the stirring state, then sequentially and slowly adding aluminum n-butoxide accounting for 0.12 percent of the weight of the Y-shaped molecular sieve (calculated by alumina), then adding silica sol accounting for 18.0 percent of the weight of the Y-shaped molecular sieve (calculated by silica), continuously stirring for 1.0 hour at constant temperature, then filtering, drying, and carrying out hydrothermal crystallization on the dried product at constant temperature for 18 hours under the pressure of 0.20MPa and the temperature of 250 ℃ to obtain the modified Y-shaped molecular sieve with high acid content. Specific properties of the molecular sieve are shown in table 1.

The application of the molecular sieve in the hydrocracking catalyst comprises the following steps:

preparation method of hydrocracking catalyst 1: uniformly mixing alumina powder, amorphous silicon-aluminum and modified Y-type molecular sieve powder, adding an acid solution, fully rolling and forming, drying for 8 hours at 100 ℃, and finally roasting for 8 hours at 600 ℃ to obtain a catalyst carrier; preparing a catalyst carrier obtained by impregnating a metal impregnation solution of W and Ni; or preparing a catalyst carrier obtained by soaking Mo and Ni in a metal dipping solution, drying for 6 hours at 120 ℃, and finally roasting for 6 hours at 500 ℃ to obtain the hydrocracking catalyst. The hydrocracking catalyst properties are as shown in table 2.

Preparation method 2 of hydrocracking catalyst: uniformly mixing alumina powder, amorphous silicon-aluminum, modified Y-type molecular sieve powder, molybdenum oxide, tungsten oxide, nickel oxide and the like, adding an acid solution, fully rolling and forming, drying for 8 hours at 100 ℃, and finally roasting for 8 hours at 550 ℃ to obtain the hydrocracking catalyst. The hydrocracking catalyst properties are as shown in table 2.

Catalyst evaluation conditions: the evaluation apparatus was a 200m1 compact hydrogenation apparatus, and the catalyst was presulfided before the activity evaluation. The properties of the raw oil and the reaction process conditions used for evaluating the catalyst activity are shown in tables 3 and 4, and the results of comparing the catalyst reaction performance are shown in table 5. When the catalyst is evaluated, raw oil firstly passes through a hydrofining catalyst bed layer and then directly enters a hydrocracking catalyst bed layer, and the organic nitrogen content in the raw oil is controlled to be lower than 10ppm when the raw oil passes through the hydrofining catalyst bed layer.

TABLE 1 physicochemical Properties of modified Y-type molecular sieves

TABLE 2 composition of the catalyst

TABLE 3 Process conditions

TABLE 4 Properties of the raw materials

TABLE 5 catalyst reactivity

The hydrocracking reaction result shows that when the conversion rate of the molecular sieve is the same as that of other molecular sieves, the reaction temperature is 8-14 ℃ lower, and the BMCI value of a tail oil product and the content of more than two-ring cycloparaffin are lower. The molecular sieve prepared by the method has better accessibility of active sites, is beneficial to the hydrogenation ring opening of polycyclic aromatic hydrocarbon, and ensures that the BMCI value of a hydrocracking product and the content of naphthenic hydrocarbon with more than two rings are lower.