CN116408133B

CN116408133B - A hydrocracking catalyst and its preparation method and application

Info

Publication number: CN116408133B
Application number: CN202111675951.5A
Authority: CN
Inventors: 鲁旭; 王书芹; 吴璇; 张占全; 王燕; 康宏敏; 侯远东; 李荣观; 雷俊伟; 刘坤红
Original assignee: Petrochina Co Ltd
Current assignee: Petrochina Co Ltd
Priority date: 2021-12-31
Filing date: 2021-12-31
Publication date: 2025-02-07
Anticipated expiration: 2041-12-31
Also published as: CN116408133A

Abstract

本发明提供了一种加氢裂化催化剂及其制备方法与应用。该催化剂包含加氢活性金属组分和载体，载体包括改性Y型分子筛和氧化铝；其中，改性Y型分子筛通过包括下述步骤的方法制备得到：在50‑120℃下，利用有机二元羧酸溶液对具有非骨架铝的HY分子筛进行脱铝处理；其中，所述有机二元羧酸溶液中的有机二元羧酸含有碳碳双键且两个羧基排列在碳碳双键的同一侧，在空间构型上为顺式结构；脱铝处理后的分子筛经洗涤、干燥得到改性Y分子筛。该分子筛能够有效实现多产高芳潜石脑油。The present invention provides a hydrocracking catalyst and a preparation method and application thereof. The catalyst comprises a hydrogenation active metal component and a carrier, wherein the carrier comprises a modified Y-type molecular sieve and alumina; wherein the modified Y-type molecular sieve is prepared by a method comprising the following steps: at 50-120°C, a HY molecular sieve having non-framework aluminum is dealuminated using an organic dicarboxylic acid solution; wherein the organic dicarboxylic acid in the organic dicarboxylic acid solution contains a carbon-carbon double bond and two carboxyl groups are arranged on the same side of the carbon-carbon double bond, and is a cis structure in spatial configuration; the molecular sieve after dealumination is washed and dried to obtain a modified Y molecular sieve. The molecular sieve can effectively achieve high-yield high-aromatic potential naphtha.

Description

Hydrocracking catalyst and preparation method and application thereof

Technical Field

The invention belongs to the technical field of chemical synthesis, and particularly relates to a hydrocracking catalyst suitable for high-yield high-aromatic naphtha as well as a preparation method and application thereof.

Background

In recent years, the market demand of the finished oil is gradually differentiated, wherein the market demand of the automotive diesel enters a negative growth area, and the market demand of the automotive gasoline is slowed down. Unlike the product oil market, the market demand for aromatic hydrocarbon and other chemical raw materials is vigorous and increases year by year at a faster rate. Meanwhile, with the gradual reduction of the consumption diesel-gasoline ratio, the diesel-gasoline outlet is also of great concern.

Hydrocracking technology has become the best means for deep processing of heavy oil to produce high quality clean middle distillate with its unique advantages. At present, the activity of the catalytic diesel hydrocracking catalyst is not very high, so that the naphtha yield is low, and the aim of improving the existing device or increasing the treatment capacity of a refinery to further increase the naphtha is difficult to achieve.

Molecular sieves are used as key materials of hydrocracking catalysts, and the performance of the molecular sieves directly influences the reaction performance of the hydrocracking catalysts. According to different production needs, the molecular sieve can be modified differently to meet the use requirement. For example, acid treatment modification of molecular sieves has been beneficial to improving the stability and cracking activity of molecular sieves, and has been widely used for a long time. However, during the acid treatment process, deposition of non-framework aluminum species inside the channels inevitably occurs, blocking the molecular sieve channels, reducing the availability and accessibility of the active sites within the molecular sieve crystals. Meanwhile, the crystallinity of the molecular sieve is reduced, which is unfavorable for obtaining the ultra-stable molecular sieve with low unit cell and high crystallinity. Therefore, how to reduce the unit cell of a molecular sieve and simultaneously increase the crystallinity of the molecular sieve as much as possible is always a challenging task, which has important significance in the technical field of molecular sieve modification.

CN105709801a discloses a method for preparing a chemical raw material hydrocracking catalyst for producing more naphtha, the naphtha yield can be up to 50wt%, but the reaction pressure is about 15Mpa, and the reaction conditions are more severe.

CN105709798a discloses a preparation method of hydrocracking catalyst and its application, and the used Y molecular sieve is obtained by hydrothermal ultrastable and ammonium fluosilicate modification, and has higher catalytic activity and selectivity when used for hydrocracking to increase the yield of heavy naphtha.

CN104229823a discloses a method for modifying an ultrastable Y molecular sieve (USY). The method is characterized in that an organic acid and an inorganic salt dealumination reagent are added simultaneously in the modification process, and the combination modification of the organic acid and the inorganic salt is carried out. The mesoporous volume of the USY molecular sieve actually prepared by the method accounts for less than 50 percent of the total volume, and the crystallinity of the USY molecular sieve is less than 85 percent.

CN101172260a discloses a preparation method of a hydrocracking catalyst, the catalyst carrier is prepared by introducing molecular sieve slurry in the gelling process of amorphous silica-alumina, and a certain weak acidic center is provided by the amorphous silica-alumina, so as to adjust the catalytic activity of the catalyst and achieve the purpose of matching the catalytic activity and selectivity.

From the application of molecular sieves with acid catalysis function in industrial catalytic processes, the performance of the molecular sieves is mainly determined by the following two aspects, namely selective adsorption and reaction. The total pore volume and the mesoporous pore volume of the molecular sieve prepared by the conventional modification method are smaller, which is not beneficial to the conversion of macromolecules of the raw materials, so that the modified molecular sieve with open pore structure, high mesoporous content and much exposed acid center can treat the raw materials with larger molecules and heavier oil products, and has more excellent performances in the aspects of improving the conversion probability of macromolecules and the like, thereby improving the level of the catalyst.

Disclosure of Invention

The invention aims to provide a hydrocracking catalyst capable of effectively realizing high-yield high-aromatic-potential naphtha and a preparation method thereof.

In order to achieve the above object, the present invention provides a hydrocracking catalyst, wherein the catalyst comprises a hydrogenation active metal component and a carrier, the carrier comprises a modified molecular sieve and alumina, wherein,

The modified molecular sieve is prepared by a method comprising the following steps:

Dealuminating a hydrogen type molecular sieve with non-framework aluminum by utilizing an organic dicarboxylic acid solution at 50-120 ℃, wherein the organic dicarboxylic acid in the organic dicarboxylic acid solution contains a carbon-carbon double bond, and two carboxyl groups are arranged on the same side of the carbon-carbon double bond and are in a cis structure in space configuration;

And washing and drying the dealuminated molecular sieve to obtain the modified molecular sieve.

In the hydrocracking catalyst, a specially modified molecular sieve is used as a carrier component, the specially modified molecular sieve is obtained by modifying a hydrogen-type molecular sieve with non-framework aluminum by using two organic dicarboxylic acids with carboxyl groups in a homeopathic structure as a dealuminating agent, the specially modified molecular sieve has high selectivity for removing ionic non-framework aluminum, the molecular sieve does not contain ionic non-framework aluminum basically, framework aluminum and polymeric non-framework aluminum are almost the same as the hydrogen-type molecular sieve with non-framework aluminum, and the specially modified molecular sieve has higher crystallinity.

In the above catalyst, the molecular sieve used preferably includes one or a combination of two or more of a Y-type molecular sieve, a beta-type molecular sieve, a ZSM-5-type molecular sieve, etc., and more preferably, the HY molecular sieve for hydrogen-type molecular sieve.

In the above catalyst, preferably, the mass ratio of the modified molecular sieve to the alumina is 25-60:75-40, more preferably, the mass ratio of the modified molecular sieve to the alumina is 35-55:65-44;

In a specific embodiment, the modified molecular sieve is present in an amount of 30% to 60%, preferably 35% to 55%, based on the total mass of the support.

In the above catalyst, preferably, the alumina is macroporous alumina.

In the above catalyst, preferably, the hydrogenation active metal component includes Ni and Mo.

In the above catalyst, the content of the hydrogenation active metal component is preferably 15% to 35% based on the total mass of the hydrocracking catalyst, and more preferably 20% to 30% based on the total mass of the hydrocracking catalyst.

In the catalyst, the hydrogen type molecular sieve with non-framework aluminum can be selected from a molecular sieve after ultra-stable hydrothermal treatment, and a molecular sieve with non-framework aluminum after chemical treatment, but is not limited to the molecular sieve.

In the above catalyst, preferably, the hydrogen-type molecular sieve having non-framework aluminum is prepared by a method comprising the steps of:

Carrying out hydrothermal treatment on the hydrogen type molecular sieve to obtain the molecular sieve after the hydrothermal treatment, wherein the molecular sieve is used as the hydrogen type molecular sieve with non-framework aluminum for subsequent dealumination treatment;

More preferably, the hydrothermally treated hydrogen form of the molecular sieve has a Na ₂ O content of no more than 0.1%, and in one embodiment, the hydrothermally treated hydrogen form of the molecular sieve has a Na ₂ O content of no more than 0.1% after ammonium exchange;

more preferably, the temperature of the hydrothermal treatment is 450-900 ℃, still more preferably, the temperature of the hydrothermal treatment is 450-800 ℃, still more preferably, the temperature of the hydrothermal treatment is 500-700 ℃;

More preferably, the time of the hydrothermal treatment is 0.1 to 10 hours, still more preferably, the time of the hydrothermal treatment is 0.5 to 6 hours, still more preferably, the time of the hydrothermal treatment is 2 to 5 hours;

More preferably, the pressure of the hydrothermal treatment is in the range of normal pressure to 0.5Mpa, still more preferably, the pressure of the hydrothermal treatment is in the range of normal pressure to 0.3Mpa, still more preferably, the pressure of the hydrothermal treatment is in the range of 0.1 to 0.2Mpa;

More preferably, the hydrothermal treatment is performed under a steam atmosphere, in a specific embodiment, the hydrothermal treatment is performed under 100% steam conditions;

In the preferred technical scheme, the hydrogen type molecular sieve after the ultra-stable treatment is obtained through hydrothermal treatment, the molecular sieve is provided with non-framework aluminum, dicarboxylic acid which contains carbon-carbon double bonds and has two carboxyl groups arranged on the same side of the carbon-carbon double bonds and is in a cis structure in space configuration is further used for dealumination treatment, and finally the ionic non-framework aluminum is basically and completely removed while framework aluminum and polymeric non-framework aluminum of the molecular sieve are basically not damaged, so that the special modified molecular sieve serving as a carrier component of the hydrocracking catalyst is obtained.

In the above catalyst, preferably, the organic dicarboxylic acid solution is maleic acid solution.

In the above catalyst, the organic dicarboxylic acid solution may be obtained by dissolving an organic dicarboxylic acid in water, or may be obtained by dissolving an anhydride of an organic dicarboxylic acid in water, and in one embodiment, the organic dicarboxylic acid solution is obtained by dissolving maleic acid in water, and in another embodiment, the organic dicarboxylic acid solution is obtained by dissolving maleic anhydride in water.

In the above catalyst, the temperature of the dealumination treatment is preferably 50 to 120 ℃, more preferably 50 to 100 ℃, and still more preferably 60 to 195 ℃.

In the above catalyst, the dealumination treatment is preferably for 0.1 to 6 hours, and more preferably for 0.5 to 3 hours.

In the above catalyst, the molar concentration of the organic dicarboxylic acid in the organic dicarboxylic acid solution is preferably 0.01 to 2mol/L based on the volume of the organic dicarboxylic acid solution, and more preferably 0.5 to 1.5mol/L based on the volume of the organic dicarboxylic acid solution.

In the above catalyst, preferably, the mass ratio of the organic dicarboxylic acid solution to the hydrogen-type molecular sieve having non-framework aluminum is 2:1 to 30:1, and more preferably, the mass ratio of the organic dicarboxylic acid solution to the hydrogen-type molecular sieve having non-framework aluminum is 5:1 to 20:1.

In one embodiment, the dealumination of the hydrogen-type molecular sieve having non-framework aluminum with the organic dicarboxylic acid solution is achieved by:

mixing a hydrogen type molecular sieve with non-framework aluminum with an organic dicarboxylic acid solution, and carrying out dealumination treatment under the stirring condition.

In the above catalyst, preferably, the washing may be performed with water, and in one embodiment, the washing is performed at a temperature of 60 to 90 ℃ and a number of times of 3 to 5 times.

In the above catalyst, preferably, the drying temperature is 100 to 160 ℃, and more preferably, the drying temperature is 110 to 130 ℃.

In the above catalyst, preferably, the drying time is 30 to 300 minutes, and more preferably, the drying time is 60 to 180 minutes.

In the above catalyst, preferably, the modified molecular sieve is a modified Y molecular sieve;

more preferably, the modified Y molecular sieve unit cell parameters are 2.4281-2.4493nm, and even more preferably, the modified Y molecular sieve unit cell parameters used are 2.4282-2.4490nm;

more preferably, the relative crystallinity of the modified Y molecular sieve is 100-130 percent, and even more preferably, the relative crystallinity of the modified Y molecular sieve is 100-130 percent;

more preferably, the silicon-aluminum atomic ratio of the modified Y molecular sieve is 5-30, and still more preferably, the silicon-aluminum atomic ratio of the modified Y molecular sieve is 6-28.

More preferably, the amount of modified Y molecular sieve B acid is more than 90% of the total acid amount, and still more preferably, the amount of modified Y molecular sieve B acid is more than 92% of the total acid amount.

In the above catalyst, preferably, the modified Y molecular sieve has a pore size of 14 to 23nm.

The invention also provides a preparation method of the hydrocracking catalyst, wherein the method comprises the following steps:

the carrier preparation step comprises kneading the modified Y-type molecular sieve and alumina to form, drying and roasting to obtain the carrier of the catalyst;

and the active component loading step is that hydrogen active metal component precursor solution is soaked on the carrier, and the hydrocracking catalyst is obtained through drying and roasting.

In the above preparation method, preferably, in the carrier preparation step, the temperature of the drying is 90 to 120 ℃.

In the above preparation method, preferably, in the carrier preparation step, the drying time is 3 to 8 hours.

In the above preparation method, preferably, in the carrier preparation step, the baking temperature is 500 to 600 ℃.

In the above preparation method, preferably, in the carrier preparation step, the time of the calcination is 3 to 8 hours.

In the above preparation method, preferably, in the active ingredient loading step, the drying temperature is 90 to 120 ℃.

In the above preparation method, preferably, in the active ingredient loading step, the drying time is 3 to 8 hours.

In the above preparation method, preferably, in the active ingredient loading step, the baking temperature is 500 to 600 ℃.

In the above preparation method, preferably, in the active ingredient loading step, the calcination time is 3 to 8 hours.

In the above production method, preferably, the hydrogen active metal component precursor is a salt and/or an oxide of the hydrogen active metal component.

The invention also provides application of the hydrocracking catalyst in preparing naphtha by diesel hydrocracking catalysis.

According to the technical scheme provided by the invention, the HY molecular sieve with non-framework aluminum is modified by using the organic dicarboxylic acid with two carboxyl groups in a homeotropic structure as the dealuminating agent to obtain the special modified Y molecular sieve, the special modified Y molecular sieve is matched with alumina to form a carrier, and the hydrogenation active component is loaded on the carrier to form the hydrocracking catalyst, so that the hydrocracking catalyst can effectively realize high-yield high-aromatic latent naphtha.

The special modified Y molecular sieve used in the technical proposal of the invention is acid modified by dicarboxylic acid with special structure, the dicarboxylic acid with special structure can form a ring transition state with ionic non-framework aluminum by virtue of the characteristic that two carboxyl groups are in cis-position on the molecular space configuration of the dicarboxylic acid with special structure, so as to promote the removal of the non-framework aluminum, under mild reaction conditions, the special modified Y molecular sieve used in the technical scheme of the invention almost does not contain ion-free non-framework aluminum, and the framework aluminum and the polymerization non-framework aluminum are approximately the same as hydrogen molecular sieves with non-framework aluminum, and have higher crystallinity.

The effect of high-efficiency dealumination and high crystallinity of the molecular sieve is maintained. Compared with the prior art, the technical scheme provided by the invention has the following beneficial effects:

1. The catalyst provided by the technical scheme of the invention adopts the special organic dicarboxylic acid modified Y molecular sieve as the cracking active component, the molecular sieve pore path after modification treatment is smooth, the accessibility of the active site in the crystal is strong, and the catalyst has the characteristics of high acid site utilization rate and high cracking selectivity.

2. The catalyst provided by the technical scheme of the invention has the characteristics of proper acid strength, smooth and regular pore canal, high cracking activity and strong selectivity.

Detailed Description

In order to more clearly illustrate the present invention, the present invention will be further described with reference to preferred embodiments. It is to be understood by persons skilled in the art that the following detailed description is illustrative and not restrictive, and that this invention is not limited to the details given herein.

Example 1

The embodiment provides a hydrocracking catalyst CAT-1, which is prepared by the following method:

Taking 200 g of HY molecular sieve with Na ₂ O content of 0.08%, and carrying out hydrothermal treatment under the condition of 100% STEAM to obtain a molecular sieve (a hydrogen type molecular sieve with non-framework aluminum) after the hydrothermal treatment, namely the HY-STEAM-1 molecular sieve, wherein the temperature of the hydrothermal treatment is 500 ℃, the pressure is 0.1MPa, and the time is 10 hours;

100 g of HY-STEAM-1 molecular sieve is dissolved in 500ml of deionized water, after the temperature is raised to 95 ℃, 29.1 g of maleic acid is added, and the mixture is stirred for 3 hours to finish dealumination treatment;

The molecular sieve after dealumination treatment is completely filtered, and is washed by deionized water at 60 ℃ for 1 hour, and the washing process is repeated for 5 times, wherein the molecular sieve after washing is dried for 180 minutes at 110 ℃ after being filtered in a drying oven, so that the modified Y molecular sieve is named as HT-Y-1 molecular sieve;

placing 35g of HT-Y-1 molecular sieve dry basis and 65 g of alumina dry basis into a kneader, mixing for 10min, adding acid water, kneading, forming, drying at 120 ℃ for 4 hours, and roasting at 550 ℃ for 4 hours to prepare a catalyst carrier, and recording as S-1;

Preparing a solution containing 4wt% of NiO and 16wt% of MoO ₃ (the concentration is based on the total mass of the solution), soaking the solution on an S-1 carrier in an equal volume, drying the solution for 4 hours at 140 ℃, and roasting the solution for 4 hours at 600 ℃ to prepare the catalyst CAT-1.

Example 2

The embodiment provides a hydrocracking catalyst CAT-2, which is prepared by the following method:

taking 200 g of HY molecular sieve with Na ₂ O content of 0.08%, and carrying out hydrothermal treatment under the condition of 100% STEAM to obtain a molecular sieve (a hydrogen type molecular sieve with non-framework aluminum) after the hydrothermal treatment, namely the HY-STEAM-2 molecular sieve, wherein the temperature of the hydrothermal treatment is 700 ℃, the pressure is 0.3MPa, and the time is 5 hours;

100 g of HY-STEAM-2 molecular sieve is dissolved in 1000ml of deionized water, after the temperature is raised to 75 ℃, 98.1 g of maleic anhydride (maleic anhydride is dissolved in the deionized water to form maleic acid solution) is added, and the mixture is stirred for 1.5 hours to finish dealumination treatment;

the molecular sieve after dealumination treatment is completely filtered, and is washed by deionized water at 75 ℃ for 1 hour, and the washing process is repeated for 4 times, the washed molecular sieve is dried for 120 minutes at 120 ℃ after being filtered, and the modified Y molecular sieve is recorded as HT-Y-2 molecular sieve;

placing 35 g of HT-Y-2 molecular sieve dry basis and 55 g of alumina dry basis into a kneader, mixing for 10min, adding acid water, kneading, forming, drying at 90 ℃ for 3 hours, and roasting at 500 ℃ for 3 hours to prepare a catalyst carrier, which is marked as S-2;

A solution containing 5wt% of NiO and 20wt% of MoO ₃ (the concentration is based on the total mass of the solution) is prepared, the solution is immersed on an S-2 carrier in an equal volume, dried for 3 hours at 90 ℃, and baked for 4 hours at a high temperature of 500 ℃ to prepare the catalyst CAT-2.

Example 3

The embodiment provides a hydrocracking catalyst CAT-3, which is prepared by the following method:

Taking 200 g of HY molecular sieve with Na ₂ O content of 0.08%, and carrying out hydrothermal treatment under the condition of 100% STEAM to obtain a molecular sieve (a hydrogen type molecular sieve with non-framework aluminum) after the hydrothermal treatment, namely the HY-STEAM-3 molecular sieve, wherein the temperature of the hydrothermal treatment is 900 ℃, the pressure is 0.5MPa, and the time is 0.1 hour;

100 g of HY-STEAM-3 molecular sieve is dissolved in 2000ml of deionized water, after the temperature is raised to 60 ℃, 348.2 g of maleic acid is added, and the mixture is stirred for 0.5 hour to finish dealumination treatment;

the molecular sieve after dealumination treatment is completely filtered, and is washed by deionized water at 90 ℃ for 1 hour, and the washing process is repeated for 3 times, the molecular sieve after washing is dried for 160 minutes at 130 ℃ after being filtered, and the modified Y molecular sieve is recorded as HT-Y-3 molecular sieve;

mixing 55 g of HT-Y-3 molecular sieve dry basis and 45 g of alumina dry basis in a kneader for 10min, adding acid water, kneading, forming, drying at 110 ℃ for 8 hours, and roasting at 600 ℃ for 8 hours to prepare a catalyst carrier, namely S-3;

Preparing a solution containing 8wt% of NiO and 22wt% of MoO ₃ (the concentration is based on the total mass of the solution), soaking the solution on an S-3 carrier in an equal volume, drying the solution for 8 hours at 120 ℃, and roasting the solution for 8 hours at 600 ℃ to prepare the catalyst CAT-3.

Comparative example 1

The comparative example provides a hydrocracking catalyst CAT-4, which is prepared by the following method:

an HY-STEAM-1 molecular sieve was prepared in the same manner as in example 1;

100 g of HY-STEAM-1 molecular sieve is dissolved in 500ml of deionized water, after the temperature is raised to 95 ℃, 93.1 g of EDTA disodium salt (EDTA disodium salt is dissolved in the deionized water to obtain EDTA solution) is added, and the mixture is stirred for 3 hours to finish dealumination treatment;

and (3) after the dealumination treatment, the molecular sieve is completely filtered, washing is carried out for 1 hour by adopting 60 ℃ deionized water, the washing process is repeated for 5 times, and the molecular sieve after washing is dried for 180 minutes at 110 ℃ after being filtered, so that the modified Y molecular sieve is named as HT-Y-4 molecular sieve.

Mixing 55 g of HT-Y-4 molecular sieve dry basis and 45 g of alumina dry basis in a kneader for 10min, adding acid water, kneading, forming, drying at 120 ℃ for 4 hours, and roasting at 550 ℃ for 4 hours to prepare a catalyst carrier, which is marked as S-4;

Preparing a solution containing 8wt% of NiO and 22wt% of MoO ₃ (the concentration is based on the total mass of the solution), soaking the solution on an S-4 carrier in an equal volume, drying the solution for 4 hours at 140 ℃, and roasting the solution for 4 hours at a high temperature of 600 ℃ to prepare the catalyst CAT-4.

Comparative example 2

The comparative example provides a hydrocracking catalyst CAT-5, which is prepared by the following method:

an HY-STEAM-1 molecular sieve was prepared in the same manner as in example 1;

mixing 55 g of HY-STEAM-1 molecular sieve dry base and 45 g of alumina dry base in a kneader for 10min, adding acid water, kneading, forming, drying at 120 ℃ for 4 hours, and roasting at 550 ℃ for 4 hours to prepare a catalyst carrier, which is marked as S-5;

Preparing a solution containing 8wt% of NiO and 22wt% of MoO ₃ (the concentration is based on the total mass of the solution), soaking the solution on an S-5 carrier in an equal volume, drying the solution for 4 hours at 140 ℃, and roasting the solution for 4 hours at 600 ℃ to prepare the catalyst CAT-5.

Experimental example 1

The results of the crystallinity, specific surface area, pore volume and pore diameter tests of the HY-STEAM-1 molecular sieve, HT-Y-2 molecular sieve, HT-Y-3 molecular sieve and HT-Y-4 molecular sieve in examples 1 to 3 and comparative example 1, respectively, are shown in Table 1.

TABLE 1 Properties of molecular sieves before and after modification with different organic acids

As can be seen from Table 1, the molecular sieve modified by maleic acid solution has significantly increased relative crystallinity, and mesoporous volume and specific surface area are also improved. Therefore, the molecular sieve modified by the maleic acid solution has proper acid strength, smooth pore canal and regularity.

Experimental example 2

The hydrocracking tests were performed using the CAT-1 catalyst, CAT-2 catalyst, CAT-3 catalyst, CAT-4 catalyst, CAT-5 catalyst provided in examples 1-3, comparative example 1, comparative example 2, respectively.

The catalyst performance evaluation was performed using a one-stage serial hydrocracking process, performed on a laboratory 100ml small high pressure hydrogenation unit. The method comprises the steps of filling a pre-refined catalyst in a first reactor, controlling the oil nitrogen content of a reaction product to be less than 10ppm, filling the catalyst to be evaluated in a second reactor, wherein the catalyst filling amount in the first reactor and the catalyst filling amount in the second reactor are 25ml, cutting the catalyst in the first reactor and the catalyst in the second reactor to 3-8mm, and diluting with an alumina carrier 1:2 after high-temperature roasting. The temperature of the first reactor was 365℃and the volume space velocity in the first reactor was 1.5h ^-1, the temperature of the second reactor was 375℃and the volume space velocity in the first reactor was 2.0h ^-1, the pressure of the hydrogenation apparatus was 10MPa, and the properties of the feedstock oil used in the hydrocracking test were as shown in Table 2. The results are shown in Table 3:

Table 2 evaluation of oil properties

TABLE 3 distribution and Properties of hydrocracked products

As can be seen from Table 3, in CAT-1 to CAT-3, as the molecular sieve content increases, the heavy naphtha yield gradually increases, the pore canal benefiting from the molecular sieve is smoother, the aromatic potential of the heavy naphtha is higher, and the cetane index of the hydrocracking diesel is also gradually increased. Compared with CAT-5 and CAT-3, under the premise of the same molecular sieve addition, the heavy naphtha yield is obviously lower than CAT-3, and the light naphtha yield is higher, which indicates that the hydrocracking activity and selectivity of the molecular sieve treated by the method are improved.

It should be understood that the foregoing examples of the present invention are provided merely for clearly illustrating the present invention and are not intended to limit the embodiments of the present invention, and that various other changes and modifications may be made therein by one skilled in the art without departing from the spirit and scope of the present invention as defined by the appended claims.

Claims

1. A hydrocracking catalyst, wherein the catalyst comprises a hydrogenation active metal component and a carrier, the carrier comprising a modified molecular sieve and alumina; wherein,

The hydrogen-type molecular sieve is subjected to hydrothermal treatment to obtain a hydrogen-type molecular sieve having non-framework aluminum for subsequent dealumination treatment; wherein the temperature of the hydrothermal treatment is 450-900° C., the time of the hydrothermal treatment is 0.1-10 hours, the pressure of the hydrothermal treatment is normal pressure-0.5 MPa, and the hydrothermal treatment is carried out under a water vapor atmosphere;

At 50-120° C., a hydrogen-type molecular sieve having non-framework aluminum is dealuminated using an organic dicarboxylic acid solution; wherein the organic dicarboxylic acid in the organic dicarboxylic acid solution contains a carbon-carbon double bond and two carboxyl groups are arranged on the same side of the carbon-carbon double bond, and has a cis structure in terms of spatial configuration; wherein the molar concentration of the organic dicarboxylic acid in the organic dicarboxylic acid solution is 0.01-2 mol/L based on the volume of the organic dicarboxylic acid solution;

The molecular sieve after dealuminization is washed and dried to obtain a modified molecular sieve;

The molecular sieves used include one or a combination of two or more of Y-type molecular sieves, beta-type molecular sieves and ZSM-5-type molecular sieves.

The catalyst according to claim 1 , wherein the hydrogen-type molecular sieve is HY molecular sieve.

3. The catalyst according to claim 2, wherein the unit cell parameter of the modified Y molecular sieve is 2.4281-2.4493 nm.

4. The catalyst according to claim 2, wherein the unit cell parameter of the modified Y molecular sieve is 2.4282-2.4490 nm.

5. The catalyst according to claim 2, wherein the modified Y molecular sieve has a silicon to aluminum atomic ratio of 5-30.

6. The catalyst according to claim 2, wherein the silicon-aluminum atomic ratio of the modified Y molecular sieve is 6-28.

7. The catalyst according to claim 1, wherein the content of the hydrogenation active metal component is 15%-35% based on the total mass of the hydrocracking catalyst.

8. The catalyst according to claim 1, wherein the content of the hydrogenation active metal component is 20%-30% based on the total mass of the hydrocracking catalyst.

9. The catalyst according to any one of claims 1, 7 and 8, wherein the mass ratio of the modified molecular sieve to alumina is 25-60:75-40.

10. The catalyst according to any one of claims 1, 7 and 8, wherein the mass ratio of the modified molecular sieve to alumina is 35-55:65-44.

11. The catalyst according to any one of claims 1, 7 and 8, wherein the hydrogenation active metal component comprises Ni and Mo.

12. The catalyst according to claim 1, wherein the _Na2O content of the hydrogen-type molecular sieve subjected to the hydrothermal treatment is not more than 0.1%.

13. The catalyst according to claim 1, wherein the temperature of the hydrothermal treatment is 450-800°C.

The catalyst according to claim 1 , wherein the temperature of the hydrothermal treatment is 500-700° C.

The catalyst according to claim 1 , wherein the hydrothermal treatment time is 0.5-6 hours.

The catalyst according to claim 1 , wherein the hydrothermal treatment time is 2-5 hours.

The catalyst according to claim 1 , wherein the pressure of the hydrothermal treatment is normal pressure to 0.3 MPa.

The catalyst according to claim 1 , wherein the pressure of the hydrothermal treatment is normal pressure-0.2 MPa.

19. The catalyst according to claim 1, wherein the organic dicarboxylic acid solution is a maleic acid solution.

20. The catalyst according to claim 1 or 19, wherein the molar concentration of the organic dicarboxylic acid in the organic dicarboxylic acid solution is 0.5-1.5 mol/L based on the volume of the organic dicarboxylic acid solution.

21. The catalyst according to claim 1 or 17, wherein the mass ratio of the organic dicarboxylic acid solution to the hydrogen-type molecular sieve having non-framework aluminum is 2:1-30:1.

22. The catalyst according to claim 1 or 17, wherein the mass ratio of the organic dicarboxylic acid solution to the hydrogen-type molecular sieve having non-framework aluminum is 5:1-20:1.

23. The catalyst according to claim 1, wherein the temperature of the dealumination treatment is 50-100°C.

24. The catalyst according to claim 1, wherein the temperature of the dealumination treatment is 60-95°C.

The catalyst according to claim 1 , wherein the dealumination treatment time is 0.1-6 hours.

The catalyst according to claim 1 , wherein the dealumination treatment time is 0.5-3 hours.

27. The method for preparing the hydrocracking catalyst according to any one of claims 1 to 26, wherein the method comprises:

Carrier preparation step: kneading the modified molecular sieve and alumina into a mixture, drying and calcining to obtain the catalyst carrier;

Active component loading step: impregnating a hydrogenation active metal component precursor solution on the carrier, and obtaining the hydrocracking catalyst through drying and calcining.

28. The preparation method according to claim 27, wherein, in the carrier preparation step, the drying temperature is 80-160°C.

29. The preparation method according to claim 27, wherein, in the carrier preparation step, the drying time is 2-10 hours.

30. The preparation method according to claim 27, wherein in the carrier preparation step, the calcination temperature is 450-650°C.

31. The preparation method according to claim 27, wherein in the carrier preparation step, the calcination time is 2-10 hours.

32. The preparation method according to claim 27, wherein in the active component loading step, the drying temperature is 80-160°C.

33. The preparation method according to claim 27, wherein, in the active component loading step, the drying time is 2-10 hours.

34. The preparation method according to claim 27, wherein in the active component loading step, the calcination temperature is 400-600°C.

35. The preparation method according to claim 27, wherein in the active component loading step, the calcination time is 2-10 hours.

36. The preparation method according to claim 27, wherein the hydrogenation active metal component precursor is a salt and/or oxide of the hydrogenation active metal component.

37. Use of the hydrocracking catalyst according to any one of claims 1 to 26 in the catalytic preparation of naphtha by diesel hydrocracking.