CN108620120B

CN108620120B - Preparation method of catalyst for catalyzing diesel oil hydrogenation conversion

Info

Publication number: CN108620120B
Application number: CN201710182259.6A
Authority: CN
Inventors: 柳伟; 关明华; 杜艳泽; 高杭; 张晓萍
Original assignee: China Petroleum and Chemical Corp; Sinopec Dalian Research Institute of Petroleum and Petrochemicals
Current assignee: Sinopec Dalian Petrochemical Research Institute Co ltd; China Petroleum and Chemical Corp
Priority date: 2017-03-24
Filing date: 2017-03-24
Publication date: 2020-11-06
Anticipated expiration: 2037-03-24
Also published as: CN108620120A

Abstract

The invention discloses a preparation method of a catalyst for catalyzing diesel oil to be subjected to hydroconversion, which comprises the following steps: (1) fully contacting alumina with liquid or gaseous unsaturated olefin, and then carrying out carbon deposition reaction in an oxygen-containing atmosphere to obtain carbon-deposited alumina; (2) the carbon-deposited alumina, the Y molecular sieve and the compound containing the hydrogenation active metals of the VIB group and the VIII group are uniformly mixed, and then the dilute nitric acid is added to the mixture to form slurry, and then the slurry is extruded into strips to be formed, dried and roasted to obtain the catalyst. The method improves the effective hydrogenation capacity of the active components of the catalyst and improves the hydrogenation reaction selectivity of the catalyst.

Description

Preparation method of catalyst for catalyzing diesel oil hydrogenation conversion

Technical Field

The invention belongs to the technical field of hydrotreatment, and particularly relates to a preparation method of a catalytic diesel oil hydroconversion catalyst.

Background

Since the new century, along with the increasing enhancement of people's environmental awareness, the stricter of national environmental regulations and the rapid development of national economy, the demand of various countries in the world for clean motor fuels is increasing. The catalytic cracking (FCC) technology is one of the main technological means for heavy oil conversion, and plays an important role in oil refining enterprises of various countries in the world. The annual processing capacity of a catalytic cracking unit in China currently exceeds 1 hundred million tons, which is second only to the United states. In the gasoline and diesel oil products, the catalytic cracking gasoline accounts for about 80 percent, and the catalytic diesel oil accounts for about 30 percent. In recent years, with the increasing weight of the quality of domestic processed crude oil, the raw materials processed by catalytic cracking are also increasingly heavy and inferior, and in addition, in order to achieve the purpose of improving the quality of gasoline or increasing the yield of propylene, a plurality of enterprises modify a catalytic cracking unit or increase the operation severity of the catalytic cracking unit, so that the quality of catalytic cracking products, particularly catalytic diesel oil, is further deteriorated.

In order to improve the utilization rate of petroleum resources, improve the overall quality level of gasoline and diesel fuel, realize the aims of product blending optimization and product value maximization and meet the continuously increasing demands for clean fuel in China, the hydrocracking process technology for producing high-added-value naphtha component and low-sulfur clean diesel fuel by the hydroconversion of high-aromatic-hydrocarbon diesel has good application prospect. Researchers at home and abroad also carry out a great deal of research work. The hydrocracking technology is adopted to convert the catalytic cracking light cycle oil into ultra-low sulfur diesel oil and a high octane number gasoline blending component.

US2010116712 discloses a catalytic diesel hydro-conversion method, which adopts a conventional process method and a cracking catalyst, raw oil is firstly pretreated and then contacted with the cracking catalyst to produce clean diesel and gasoline with high new-value. However, this method cannot selectively reduce the hydrogenation saturation of gasoline components, and therefore, the octane number loss of gasoline products is large.

EP20110834653 discloses a preparation method of a polycyclic aromatic hydrocarbon hydroconversion catalyst, the catalyst carrier is composed of a beta molecular sieve and pseudo-boehmite, active metal components of a group VIB and a group VIII are added by a conventional method, but the catalyst has strong saturation capacity on gasoline components, and is not beneficial to catalyzing the process of producing high octane gasoline by diesel hydroconversion.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a preparation method of a catalytic diesel oil hydro-conversion catalyst, which improves the effective hydrogenation capacity of active components of the catalyst and improves the hydrogenation reaction selectivity of the catalyst.

The preparation method of the catalytic diesel oil hydroconversion catalyst comprises the following steps: (1) fully contacting alumina with liquid or gaseous unsaturated olefin, and then carrying out carbon deposition reaction in an oxygen-containing atmosphere to obtain carbon-deposited alumina; (2) the carbon-deposited alumina, the Y molecular sieve and the compound containing the hydrogenation active metals of the VIB group and the VIII group are uniformly mixed, and then the dilute nitric acid is added to the mixture to form slurry, and then the slurry is extruded into strips to be formed, dried and roasted to obtain the catalyst.

In the method, the unsaturated olefin in the step (1) is normal or isomeric olefin and diolefin with the carbon number of 2-10; wherein the olefin is in sufficient contact with the molecular sieve, which means that unsaturated olefin diffuses into the molecular sieve; when a gaseous unsaturated olefin is used, the gaseous unsaturated olefin is contacted with the molecular sieve under the following conditions: the pressure is 0.1-1.0 MPa, and the contact time is 0.1-2 hours; when a liquid unsaturated hydrocarbon is used, the liquid unsaturated olefin is contacted with the molecular sieve under the following conditions: the pressure is 0.1-1.0 MPa, the contact time is 0.5-4 hours, and the molecular sieve is completely immersed in the liquid olefin. The olefin is fully contacted with the molecular sieve at normal temperature, and the unsaturated hydrocarbon state is a normal-temperature phase state.

The oxygen-containing atmosphere in the step (1) is one of air, a mixture of oxygen and nitrogen or a mixture of oxygen and inert gas, the volume fraction of oxygen in a gas phase is 10-100%, and air is preferred; the carbon deposition reaction conditions are as follows: the reaction temperature is 50-500 ℃, preferably 100-400 ℃, and the reaction time is 1-200 hours, preferably 10-100 hours.

In the carbon-deposited alumina in the step (1), the weight of the carbon-deposited alumina is taken as a reference, the carbon content is 0.5wt% to 20wt%, preferably 2wt% to 15wt%, and the pore volume ratio of the carbon-deposited alumina to the non-carbon-deposited alumina is 1:10 to 1: 1.5.

In the method, the VIB group active metal in the step (2) is selected from W and/or Mo, the VIII group active metal is selected from Ni and/or Co, the content of VIB group metal compounds in the mixture is 4wt% -20 wt% according to corresponding oxides, and the content of VIII group metal compounds is 2wt% -15 wt% according to corresponding oxides. The concentration of the dilute nitric acid is 3-30 wt%.

In the method of the invention, the drying conditions in the step (2) are as follows: drying for 2-8 hours at 90-150 ℃;

in the method, after the drying process in the step (2) is finished, carbon deposit in the alumina can be removed by roasting in an oxygen-containing atmosphere, and can also be remained in the catalyst by roasting in an inert atmosphere; the roasting conditions are as follows: roasting at 300-600 ℃ for 1-5 hours. The inert atmosphere is selected from N₂Helium, neon or argon. The oxygen-containing atmosphere is one of air, a mixture of oxygen and nitrogen or a mixture of oxygen and inert gas, the volume fraction of oxygen in a gas phase is 10% -100%, and air is preferred.

The method of the present invention may also be carried out by a saturation impregnation method. Firstly mixing the alumina powder subjected to carbon deposition treatment with a Y molecular sieve to prepare a carrier, and then carrying out saturated impregnation on the carrier by using an aqueous solution containing salts of VIII groups and VIB groups; the active metal of the VIB group is selected from W and/or Mo, the active metal of the VIII group is selected from Ni and/or Co, the content of the VIB group metal compound in the impregnation liquid is 10-40 g/100mL according to corresponding oxides, the content of the VIII group metal compound is 3-20 g/100mL according to corresponding oxides, and the concentration of the metal compound in the impregnation liquid can be correspondingly adjusted according to the needs of products.

According to the catalytic diesel oil hydroconversion catalyst prepared by the method, based on the weight of the catalyst, the VIB group metal content is 4-20 wt% calculated by oxides, the VIII group metal content is 2-15 wt% calculated by oxides, the Y molecular sieve content is 30-84%, preferably 40-80%, the alumina content is 10-64%, preferably 20-60%, and the carbon content is 0.2-12%, preferably 2-5%.

The catalytic diesel conversion catalyst prepared by the method can be applied to the reaction of producing high-octane gasoline by catalyzing the hydrogenation conversion of diesel oil, and the general operating conditions are as follows: the reaction temperature is 340-440 ℃, and preferably 360-430 ℃; the reaction pressure is 4.0-15.0 MPa, preferably 6.0-12.0 MPa; the liquid hourly space velocity is 0.2-6.0 h^-1Preferably 0.5 to 3.0 hours^-1(ii) a The volume ratio of hydrogen to oil is 100-2000, preferably 500-1500.

The reaction process for producing high-octane gasoline by catalytic diesel oil hydrogenation conversion is generally to carry out hydrogenation denitrification on a catalytic diesel oil raw material, and then carry out hydrocracking reaction on the denitrification reaction product oil to generate a high-octane gasoline component. The hydrocracking catalyst for hydrocracking reaction usually uses Y molecular sieve and alumina as carrier, and W-Ni or Mo-Ni as active metal component. Alumina in the hydrocracking catalyst in the conventional hydrocracking reaction process is used as a matrix for dispersing the Y molecular sieve and dispersing a cracking center, and meanwhile, the alumina has better hydrogenation activity metal dispersing performance, is favorable for further hydrogenation saturation of a cracked product, and improves the properties of the cracked product. However, for the technology of producing high-octane gasoline by catalytic diesel oil hydroconversion, a cracking catalyst is required to have a certain hydrogenation capacity to terminate carbocation, inhibit excessive cracking and improve the stability of the catalyst, the hydrogenation active metal loaded on a molecular sieve is beneficial to improving the matching of hydrogenation and an acid center and reducing excessive cracking, the hydrogenation activity belongs to effective hydrogenation activity, and the excessive hydrogenation activity of the active metal on alumina is easy to cause the saturation of aromatic hydrocarbon in a gasoline product, so that the octane number of the gasoline product is reduced, and the octane number of the gasoline product is not beneficial to improving the octane number of the gasoline product, which is undesirable for the technology of producing high-octane gasoline by catalytic diesel oil hydroconversion. The conventional preparation method is generally to directly prepare the alumina and molecular sieve composite carrier, then to impregnate the active components by an impregnation method, the increase or decrease of the active components on the alumina and the molecular sieve are synchronous, if the hydrogenation activity on the molecular sieve is improved, the overhigh hydrogenation activity on the alumina easily causes over hydrogenation saturation, and if the hydrogenation activity on the alumina is reduced, the over hydrogenation activity on the Y molecular sieve is reduced, so that the normal hydrogenation activity of the Y molecular sieve is influenced, and the over cracking is caused. Therefore, the contradiction which is difficult to solve exists between the hydrogenation capacities of the active components on the alumina and the molecular sieve in the balance catalyst, and the two are difficult to be considered simultaneously.

According to the method, the alumina carrier with reasonable carbon deposition amount is obtained by filling part of pore passages and surfaces of alumina with carbon deposition formed by pre-performing carbon deposition treatment on alumina powder, so that in the subsequent process of impregnating hydrogenation active components, the loading amount of the active components on the alumina is reduced, the hydrogenation activity of the active metals loaded on the alumina is inhibited while the hydrogenation activity of the active metals on the Y molecular sieve is not influenced, therefore, the catalyst has better hydrogenation reaction selectivity, the excessive hydrogenation of gasoline components generated by cracking on the alumina can be reduced, the octane number of gasoline products is improved, the effective hydrogenation capacity of the catalyst is improved, the active components are more easily loaded on the surfaces of the molecular sieves in the impregnation process, and the usage amount of an active component impregnating solution is reduced.

Detailed Description

The invention is further illustrated by the following examples, but is not limited thereto. The percentages referred to in the examples are mass percentages (except for relative crystallinity), and the liquid-solid ratios are liquid-solid mass ratios.

Example 1

(1) Putting 200g of industrially produced macroporous alumina into a closed container filled with butadiene atmosphere, controlling the pressure to be 0.3MPa, fully contacting for 20 minutes, and then heating for 80 hours at 200 ℃ in air atmosphere;

(2) taking 50g of alumina obtained in the step (1), 80g of industrial modified Y molecular sieve and MoO₃15g and 20g of nickel nitrate are mixed, 4g/100mL of dilute nitric acid is added into the mixture, the mixture is mixed and rolled in a mixer to be extrudable, and then strip extrusion molding is carried out;

(3) and (3) drying the sample in the step (2) at 120 ℃ for 4h in the air atmosphere, and then transferring the sample to the nitrogen atmosphere to roast the sample for 3h at 500 ℃ to obtain the catalyst C1.

Example 2

(1) Soaking 200g of macroporous alumina industrially produced in heptene for 4 hours, and then heating at 180 ℃ for 150 hours in an air atmosphere;

(2) mixing 50g of alumina obtained in the step (1) and 100g of industrial modified Y molecular sieve, adding 4g/100mL of dilute nitric acid, mixing, rolling, extruding into strips, molding in a mixer, and drying at 120 ℃ for 4h to obtain the carrier of the embodiment 2;

(3) preparing Mo-Ni dipping solution and adding MoO₃Adding basic nickel carbonate into distilled water to prepare a partial Mo-Ni impregnation solution, and adjusting MoO in the mixed solution according to the oxide of the metal salt₃30g/100mL and 10g/100mL of nickel oxide;

(4) and (3) soaking the catalyst carrier obtained in the step (2) for 2h by using the Mo-Ni soaking solution obtained in the step (3) according to the liquid-solid ratio of 3:1, drying the catalyst carrier for 2h at 150 ℃ in an air atmosphere, and then transferring the dried catalyst carrier to a helium atmosphere for roasting for 4h at 400 ℃ to obtain a catalyst C2.

Example 3

(1) Soaking 200g of macroporous alumina industrially produced in heptene for 2 hours, and then heating at 300 ℃ for 200 hours in an air atmosphere;

(2) mixing 80g of alumina obtained in the step (1), 80g of industrial modified Y molecular sieve, 22g of ammonium metatungstate and 20g of nickel nitrate, adding 4g/100mL of dilute nitric acid, mixing and rolling in a mixer until the mixture is extrudable, and then extruding and forming;

(3) and (3) drying the sample in the step (2) at 120 ℃ for 4h in the air atmosphere, and then transferring the dried sample into the nitrogen atmosphere at 550 ℃ for roasting for 3h to obtain the catalyst C3.

Example 4

(1) Soaking 200g of industrially produced macroporous alumina for 2 hours in hexadiene, and then heating for 120 hours at 400 ℃ in an air atmosphere;

(2) mixing 50g of alumina obtained in the step (1), 100g of modified Y molecular sieve, 30g of ammonium metatungstate and 60g of nickel nitrate, adding 4g/100mL of dilute nitric acid, mixing and rolling in a mixer until the mixture is extrudable, and extruding and forming;

(3) and (3) drying the sample in the step (2) at 120 ℃ for 4h in the air atmosphere, and then transferring the sample to a nitrogen atmosphere to roast the sample for 3h at 450 ℃ to obtain the catalyst C4.

Example 5

The same procedure as in example 1, except that the calcination atmosphere in the step (3) was changed to air, was conducted to obtain catalyst C5.

Example 6

Similar to example 2, except that the atmosphere for calcination in step (3) was changed to air, catalyst C6 was obtained.

Comparative example 1

80g of the modified Y molecular sieve and MoO used in example 1 were directly mixed with 50g of the commercial macroporous alumina used in example 1 without carbon deposition treatment₃15g and 20g of nickel nitrate are mixed, 4g/100mL of dilute nitric acid is added to be mixed and rolled in a mixer to be extrudable, strip extrusion molding is carried out on a strip extrusion machine, drying is carried out for 4h at 120 ℃ in air atmosphere, and roasting is carried out for 4h at 500 ℃ to obtain the catalyst B1.

Comparative example 2

Taking 50g of the industrial macroporous alumina used in the example 2, directly mixing with 100g of the modified Y molecular sieve used in the example 2 without carbon deposition treatment, adding 4g/100mL of dilute nitric acid, mixing and rolling in a mixer to be extrudable, extruding and molding on an extruding machine, drying at 120 ℃ for 4h in an air atmosphere, and roasting at 500 ℃ for 4h to obtain a catalyst carrier of the comparative example 2, and then preparing the catalyst B2 by using the impregnation solution used in the example 2 according to the same impregnation method.

The main physical and chemical properties of the aluminas of examples 1 to 4 and comparative examples 1 to 2 are shown in Table 1.

The physical and chemical properties of the catalysts of examples 1 to 4 and comparative examples 1 to 2 are shown in Table 2.

Table 1 examples and comparative examples alumina physical properties.

Table 2 catalyst physical and chemical properties of examples and comparative examples.

Example 5

In order to examine the reaction performance of the catalysts prepared in the examples and comparative examples, the catalysts were subjected to an evaluation test in a small-sized apparatus using a single-stage tandem one-pass process, one-way packing of a hydrocracking pretreatment catalyst FF-36 (china petrochemical and petrochemical institute) widely used in the industry, and two-way packing of hydrocracking catalysts according to examples 1 and 2 and comparative examples 1 and 2, respectively, the properties of the raw materials used in the examples and comparative examples, evaluation conditions, and evaluation results are shown in tables 3 to 6.

TABLE 3 Properties of the feedstock.

Table 4 example catalyst operating conditions.

Table 5 comparative example catalyst operating conditions.

Table 6 catalyst evaluation results of examples.

Table 6 (continuous) evaluation results of catalysts of comparative examples.

The comparative results of the process tests of the examples and the comparative examples show that the catalyst prepared by the method and the process technology obviously improve the effective hydrogenation capacity of the catalyst and can greatly improve the octane number of gasoline products.

Claims

1. A preparation method of a catalyst for catalyzing diesel oil to be subjected to hydroconversion is characterized by comprising the following steps: (1) fully contacting alumina with liquid or gaseous unsaturated olefin, and then carrying out carbon deposition reaction in an oxygen-containing atmosphere to obtain carbon-deposited alumina; (2) the carbon-deposited alumina, the Y molecular sieve and the compound containing the hydrogenation active metals of the VIB group and the VIII group are uniformly mixed, and then the dilute nitric acid is added to the mixture to form slurry, and then the slurry is extruded into strips to be formed, dried and roasted to obtain the catalyst.

2. The method of claim 1, wherein: the unsaturated olefin in the step (1) is normal or isomeric olefin and diolefin with the carbon atom number of 2-10; when a gaseous unsaturated olefin is used, the gaseous unsaturated olefin is contacted with the molecular sieve under the following conditions: the pressure is 0.1-1.0 MPa, and the contact time is 0.1-2 hours; when a liquid unsaturated hydrocarbon is used, the liquid unsaturated olefin is contacted with the molecular sieve under the following conditions: the pressure is 0.1-1.0 MPa, the contact time is 0.5-4 hours, and the molecular sieve is completely immersed in the liquid olefin.

3. The method of claim 1, wherein: the oxygen-containing atmosphere in the step (1) is one of air, a mixture of oxygen and nitrogen or a mixture of oxygen and inert gas, and the volume fraction of oxygen in a gas phase is 10-100%; the carbon deposition reaction conditions are as follows: the reaction temperature is 50-500 ℃, and the reaction time is 1-200 hours.

4. The method of claim 1, wherein: in the carbon-deposited alumina in the step (1), the carbon content is 0.5-20 wt% based on the weight of the carbon-deposited alumina.

5. The method of claim 1, wherein: the pore volume ratio of the carbon-deposited alumina to the non-carbon-deposited alumina in the step (1) is 1: 10-1: 1.5.

6. The method of claim 1, wherein: the VIB group active metal in the step (2) is selected from W and/or Mo, the VIII group active metal is selected from Ni and/or Co, the content of VIB group metal compounds in the mixture is 4wt% -20 wt% according to corresponding oxides, and the content of VIII group metal compounds is 2wt% -15 wt% according to corresponding oxides.

7. The method of claim 1, wherein: after the drying process in the step (2) is finished, the carbon deposit in the alumina is roasted and removed in an oxygen-containing atmosphere or roasted and remained in the catalyst in an inert atmosphere; the roasting conditions are as follows: roasting at 300-600 ℃ for 1-5 hours.

8. The method of claim 1, wherein: firstly, mixing the carbon-deposited alumina powder obtained in the step (1) with a Y molecular sieve to prepare a carrier, and then, carrying out saturated impregnation on the carrier by using an aqueous solution containing VIII group and VIB group salts; wherein the group VIB active metal is selected from W and/or Mo, and the group VIII active metal is selected from Ni and/or Co.

9. The method of claim 1, wherein: based on the weight of the catalyst, the content of VIB group metal is 4-20 wt% calculated by oxide, the content of VIII group metal is 2-15 wt% calculated by oxide, the content of Y molecular sieve is 30-84%, the content of alumina is 10-64%, and the content of carbon is 0.2-12%.

10. According to claim 1The application of the catalytic diesel oil hydroconversion catalyst prepared by the method in the reaction of producing high-octane gasoline by catalytic diesel oil hydroconversion is as follows: the reaction temperature is 340-440 ℃, the reaction pressure is 4.0-15.0 MPa, and the liquid hourly space velocity is 0.2-6.0 h^-1The volume ratio of hydrogen to oil is 100-2000.