CN114602481A

CN114602481A - Preparation method of nano composite nickel-based catalyst

Info

Publication number: CN114602481A
Application number: CN202011449845.0A
Authority: CN
Inventors: 郑明远; 刘文飞; 姜宇; 郭为磊; 赵宇; 张荣军; 张涛
Original assignee: Kairui Environmental Protection Technology Co ltd; Dalian Institute of Chemical Physics of CAS
Current assignee: Kairui Environmental Protection Technology Co ltd; Dalian Institute of Chemical Physics of CAS
Priority date: 2020-12-09
Filing date: 2020-12-09
Publication date: 2022-06-10
Anticipated expiration: 2040-12-09
Also published as: CN114602481B

Abstract

The invention discloses a nano composite nickel-based catalyst and a preparation method and application thereof. The catalyst is prepared by taking nickel as a main active component, simultaneously containing an auxiliary agent component which comprises one or more than two of zirconium oxide, iron oxide and cobalt oxide, and an auxiliary agent component which comprises one or more than two of titanium oxide, tin oxide, tungsten oxide, molybdenum oxide and magnesium oxide, taking silica gel and alumina gel as binders, adopting a coprecipitation method, and then carrying out molding and roasting to obtain the catalyst. The catalyst has good activity in the hydrodesulfurization reaction of oil products, and needs to be reduced before use.

Description

Preparation method of nano composite nickel-based catalyst

Technical Field

The invention relates to a preparation method of a nano composite nickel-based catalyst. In particular to a method for preparing a catalyst by using a coprecipitation method, wherein the catalyst takes metallic nickel as a main active component and is used for mercaptan catalytic thioetherification reaction in gasoline.

Technical Field

In order to reduce the pollution of sulfur in gasoline and diesel oil to the atmosphere and the environment, strict regulations are set for the sulfur content of gasoline and diesel oil in various countries in the world. The traditional gasoline hydrodesulfurization process has large octane value loss while deep desulfurization, and a new process technology for producing the ultra-low sulfur gasoline is developed continuously abroad at present, wherein the CDHydro & CDHDS process developed by the American CD TECH company and the Prime G + process developed by the French Axens company have wide application prospects. The adopted process route is to catalyze diolefin in an oil product to perform a thioetherification reaction with mercaptan under mild critical conditions to generate larger-molecular thioether, simultaneously perform selective hydrogenation saturation on the diolefin in the gasoline, then divide the gasoline into a light component and a heavy component through a rectification process, wherein the light component is the blending component rich in olefin and having a higher octane number, and the heavy component is subjected to deep hydrodesulfurization, and the two processes can produce the gasoline with ultra-low sulfur and extremely little octane number loss.

At present, the research on the technology in foreign countries mainly focuses on the process aspect, and the reports on the catalyst used in the thioetherification reaction are less. Most of the catalysts adopt noble metal elements such as Pt and Pd with selective hydrogenation function, and the catalysts usually have stronger olefin saturation activity and higher cost. The nickel-based catalyst has relatively low price and moderate activity, and is attracted by researchers in recent years. In the aspect of thioetherification, Ni/Al2O3 catalysts [ petroleum refining and chemical, 2010,41,37-42 ] and Mo-Ni/Al2O3 catalysts [ petro-chemical, 2015,31,18-24 ] have been reported. However, the activity and selectivity of the catalyst are still unsatisfactory.

Disclosure of Invention

The invention provides a simple coprecipitation method for preparing a nano composite catalyst, high catalytic activity is obtained, meanwhile, an auxiliary agent component is in close contact with nickel, a synergistic effect is generated, and optimal reaction selectivity and catalyst stability are obtained.

In order to achieve the purpose, the invention adopts the technical scheme that:

in one aspect, the present invention provides a nanocomposite nickel-based catalyst;

the catalyst consists of an active component, an auxiliary agent I, an auxiliary agent II, silicon oxide and a binder;

the active component is nickel, and the content of nickel element in the catalyst is 30-80 wt%;

the first auxiliary agent is one or more than two of zirconium oxide, iron oxide and cobalt oxide, the total content in the catalyst is 0.5-10 wt% calculated by metal, and the total content is calculated by metal, namely the content of the metal in the first auxiliary agent/the total amount of the reduced catalyst;

the second auxiliary agent is one or more than two of titanium oxide, tin oxide, tungsten oxide, molybdenum oxide and magnesium oxide, and the total content in the catalyst is 0.5-10 wt% calculated by metal;

the adhesive is formed by mixing alumina gel or alumina gel and silica gel, the alumina gel contains alumina, the silica gel contains silica, the total content of the adhesive in the catalyst is 5-30 wt% calculated by the alumina and the silica, and the mass ratio of the silica to the alumina in the adhesive is 0-10;

the total content of the silica in the catalyst is 1-15 wt%, and the total content of 1-15 wt% does not include the content of silica in the binder.

The particle size of the active component is 2-15 nm;

in the catalyst, the content of nickel element is 40-70 wt%; the total content of the additive I calculated by metal is 0.5-5 wt%; the total content of the second auxiliary agent calculated by metal is 0.5-5 wt%; the total content of silica in the catalyst is 5-15 wt%;

the total content of the binder in the catalyst is 5-20 wt% calculated by alumina and silica, and the mass ratio of the silica to the alumina in the binder is 0-5.

In another aspect, the present invention provides a method for preparing the above catalyst;

the catalyst is prepared by adopting a coprecipitation method, a catalyst active component precursor, an auxiliary agent precursor and silica gel are dissolved in water, a precipitator is added for precipitation, the catalyst precursor is obtained by separation and drying after the precipitation is finished, a binder is added, and the nano composite nickel-based catalyst is obtained by drying and roasting after the forming process; the catalyst is reduced before use. The content of each component in the catalyst is calculated by the reduced catalyst, the active component is calculated by nickel, and the first auxiliary agent and the second auxiliary agent are both calculated by metal content.

The specific preparation process of the catalyst comprises the following steps:

(1) dissolving soluble salt of nickel in water, adding soluble salt of an auxiliary agent I, adding soluble salt of an auxiliary agent II, stirring until the soluble salt is completely dissolved, adding silica gel, and continuously stirring until the soluble salt and the auxiliary agent II are uniformly mixed;

(2) adding one or more aqueous solutions of ammonium carbonate, ammonium bicarbonate, ammonia water, sodium hydroxide, sodium carbonate and a sodium bicarbonate precipitator into the solution under the condition of stirring, adjusting the pH value of the reaction material to 6.0-11.0, filtering or centrifugally separating precipitates after the precipitation is finished, and drying at 80-150 ℃ to obtain a catalyst precursor;

(3) adding a binder into the catalyst precursor, preparing molding particles by adopting an extrusion molding method, an extrusion molding method or a rolling molding method, drying at 80-150 ℃, and roasting at 250-550 ℃ for 0.5-4h to obtain the nano composite nickel-based catalyst;

(4) before use, the nano composite nickel-based catalyst needs to be reduced for 0.5-5h at the temperature of 150-500 ℃ in a hydrogen atmosphere.

The soluble nickel salt is one or more of nickel acetate, nickel sulfate, nickel chloride and nickel nitrate; the soluble salt of the first auxiliary agent is one or more of chloride, thionyl chloride, nitrate, nitrite, phosphate, sulfate, sulfite and zirconium oxychloride of zirconium, iron and cobalt; the soluble salt of the second auxiliary agent is one or more of chloride, nitrate, phosphate, sulfate, tungstate, metatungstate and molybdate of titanium, tin, tungsten, molybdenum and magnesium.

The formed particles are spherical, granular, tooth-shaped, annular, flaky and strip-shaped catalyst particles with the diameter, length and thickness of 1-10 mm.

The silica gel contains 10-50 wt% of silica, and the aluminum gel contains 5-20 wt% of aluminum oxide.

The nano composite nickel-based catalyst can be applied to hydrodesulfurization reaction of oil products, and in particular can be used for mercaptan catalytic thioetherification reaction in gasoline.

The reaction is carried out in a fixed bed reactor, the reaction temperature is 80-150 ℃, the hydrogen pressure is 0.1-2MPa, the hydrogen-oil volume ratio is 100-10000, and the reaction space velocity is 0.1-10h^-1。

The application of the nano composite nickel-based catalyst prepared by the invention in the hydrodesulfurization reaction of oil products is not limited to a fixed bed reactor, and the nano composite nickel-based catalyst can also be used in a reaction rectification reaction system, and can realize desulfurization and product refining at the same time.

The invention has the following advantages:

1) the synthesis method is simple, the active components are in a high dispersion state with a nano scale, the nickel catalyst has high activity, and can catalyze mercaptan in the oil product to generate thioetherification reaction under mild conditions to generate larger-molecular thioether, so that the gasoline hydrodesulfurization is realized.

2) The cocatalyst in the catalyst can avoid the sintering of the nickel nano particles in the reduction and use processes, and improve the stability of the catalyst.

3) The catalyst is modified by using multiple metals to modify the nickel component, has a synergistic effect, and has high conversion rate of mercaptan on the catalyst.

Drawings

FIG. 1 is an XRD spectrum of catalyst 1 before reduction;

FIG. 2 is an XRD spectrum of catalyst 2 before reduction;

FIG. 3 is an XRD spectrum of catalyst 6 before reduction;

fig. 4 is an XRD spectrum before reduction of catalyst 7.

Detailed Description

The present invention will be described in detail with reference to specific examples, which are not intended to limit the scope of the present invention.

Example 1

Preparation of catalyst 1: 100g of nickel sulfate hexahydrate is dissolved in 1000ml of water, the mixture is stirred and dissolved, zirconium oxychloride containing 0.4g of zirconium and stannous chloride containing 0.4g of tin are added, 8g of silica gel containing 40% of silicon dioxide are added under stirring, the mixture is stirred to be uniform, 10% sodium hydroxide solution is dropwise added until the pH value is 8, the mixture is filtered, the mixture is dried at 120 ℃, the mixture is ground into powder, 5g of silica gel containing 40% of silicon dioxide and 20g of alumina gel containing 15% of aluminum oxide are added, the mixture is uniformly mixed, the mixture is extruded and formed, the diameter of the mixture is 2mm, the mixture is roasted at 450 ℃ for 2 hours to obtain a catalyst 1, and the catalyst 1 is reduced for 3 hours at 400 ℃ in a hydrogen atmosphere before use.

Example 2

Preparation of catalyst 2: 100g of nickel sulfate hexahydrate is dissolved in 1000ml of water, the mixture is stirred and dissolved, 0.4g of ferric nitrate containing iron and 0.4g of stannous chloride containing tin are added, 8g of silica gel containing 40% of silicon dioxide are added under stirring, the mixture is stirred to be uniform, 10% of sodium carbonate solution is dropwise added until the pH value is 8, the mixture is filtered, the mixture is dried at 120 ℃, the mixture is ground into powder, 5g of silica gel containing 40% of silicon dioxide and 20g of alumina gel containing 15% of alumina are added, the mixture is uniformly mixed, the mixture is extruded into strips and molded, the diameter is 2mm, the strips are roasted at 450 ℃ for 2 hours to obtain a catalyst 2, and the catalyst 2 is reduced for 3 hours at 400 ℃ in a hydrogen atmosphere before use.

Example 3

Preparation of catalyst 3: 90g of nickel dichloride hexahydrate is dissolved in 1000ml of water, the mixture is stirred and dissolved, cobalt nitrate containing 0.4g of cobalt and stannous chloride containing 0.4g of tin are added, 8g of silica gel containing 40% of silicon dioxide are added under stirring, the mixture is stirred to be uniform, 10% sodium carbonate solution is dripped until the pH value is 8, the mixture is filtered, the mixture is dried at 120 ℃, the mixture is ground into powder, 5g of silica gel containing 40% of silicon dioxide and 20g of alumina gel containing 15% of alumina are added, the mixture is uniformly mixed, the mixture is extruded and formed, the diameter of the mixture is 2mm, the mixture is roasted at 450 ℃ for 2 hours to obtain a catalyst 3, and the catalyst 3 is reduced at 400 ℃ for 3 hours in a hydrogen atmosphere before use.

Comparative example 1

Catalyst 4 preparation (addition of aid one only, no addition of aid two): the procedure of preparation was the same as in example 1, and zirconium oxychloride (0.8 g) was added thereto, and stannous chloride was not added thereto, to obtain catalyst 4.

Comparative example 2

Catalyst 5 preparation (addition of auxiliary two only, no addition of auxiliary one): the procedure is as in example 1, with tin 0.8g of stannous chloride and no zirconium oxychloride being added, giving catalyst 5.

Comparative example 3

Catalyst preparation referring to example 1, no silica gel was added prior to the addition of the precipitant to give catalyst labeled catalyst 6.

Comparative example 4

Catalyst preparation referring to example 2, no silica gel was added prior to the addition of the precipitant to give catalyst labeled catalyst 7.

Comparative example 5

Preparation of alumina supported catalyst: preparing nickel nitrate, zirconium oxychloride and stannous chloride into mixed solution, adding 40% silica gel, and soaking in Al₂O₃The supported catalyst 8, in which the supported amount of nickel was 60 wt%, the supported amount of zirconium was 1.3 wt%, the supported amount of tin was 1.3 wt%, and the amount of silica on the catalyst was 10 wt%, was dried at 120 ℃ and calcined at 500 ℃ to obtain a catalyst, which was reduced in hydrogen at 400 ℃ for 3 hours before use.

Example 4

Evaluation of catalyst reaction Performance: a fixed bed hydrogenation reaction device is adopted, and the performance of the catalyst is evaluated by taking the gasoline containing the thiol as a raw material. The reactor was charged with 1g of catalyst, and the catalyst performance was evaluated at 120 ℃ under conditions of 1.0MPa hydrogen, 3ml/h raw material flow, and 60ml/min hydrogen flow. The reaction was sampled every 2 hours. Catalyst activity is expressed in mercaptan conversion. The results of the reaction evaluations of the various catalysts are shown in tables one and two.

TABLE mercaptan conversion on various catalysts

TABLE thioether Selectivity on various catalysts

From the above reaction results, it can be seen that the catalyst of the present invention has a good catalytic performance in thiol thioetherification reactions. Compared with the catalyst 4 and the catalyst 5 which are not simultaneously added with the first auxiliary agent and the second auxiliary agent, the selectivity of the catalyst 1, the catalyst 2 and the catalyst 3 which simultaneously contain the first auxiliary agent and the second auxiliary agent is higher, and the combined action of the first auxiliary agent and the second auxiliary agent can effectively improve the catalytic activity. In addition, compared with the catalyst 8 prepared by the conventional impregnation method, the catalyst prepared by the method has the advantages of obviously improved selectivity and better stability, and the catalyst prepared by the synthesis method has more excellent performance.

Example 5

XRD characterization results and particle size calculation before reduction of the catalysts are shown in figures 1-4, which are XRD spectrograms before reduction of catalyst 1, catalyst 2, catalyst 6 and catalyst 7 respectively.

Calculating the particle size of the active component before reduction of each catalyst according to the XRD spectrogram

Catalyst and process for preparing same	Calculating the particle size/nm of the active component according to the XRD spectrogram
		Before reduction of catalyst 1	5.1
Before reduction of catalyst 2	6.0
		Before reduction of catalyst 6	16.4
Before reduction of catalyst 7	20.4

According to the characterization and calculation results, the catalysts 1 and 2 have obvious advantages in the particle size of the active components before reduction compared with the catalysts 6 and 7, and the reduction temperature of the catalysts is lower than the roasting temperature of the catalysts, so that the active centers of the catalysts are maintained at a smaller particle size after reduction, which indicates that the catalysts obtained by the synthesis method of the invention have smaller particle size and are stable in the reaction process.

Claims

1. A nano composite nickel-based catalyst is characterized in that:

the first auxiliary agent is one or more of zirconia, iron oxide and cobalt oxide, and the total content in the catalyst is 0.5-10 wt% calculated by metal;

2. The catalyst of claim 1, wherein the active component has a particle size of 2-15 nm;

3. The preparation method of the nanocomposite nickel-based catalyst according to claim 1, wherein the catalyst is prepared by a coprecipitation method, and the coprecipitation method comprises the following steps: dissolving an active component precursor, an auxiliary agent precursor and silica gel in water, adding a precipitator for precipitation, separating and drying after the precipitation is finished to obtain a catalyst precursor, adding a binder, drying and roasting after the forming process to obtain the nano composite nickel-based catalyst; the catalyst needs to be reduced before use.

4. The method of preparing a nanocomposite nickel-based catalyst according to claim 3, characterized in that:

the coprecipitation method specifically comprises the following steps:

(1) dissolving soluble nickel salt in water, adding soluble salt of an auxiliary agent I, adding soluble salt of an auxiliary agent II, stirring until the soluble salt is completely dissolved, adding silica gel, and continuously stirring until the mixture is uniformly mixed to obtain a solution A;

(2) adding a water solution of a precipitator into the solution A under the condition of stirring, adjusting the pH value to 6.0-11.0, precipitating, filtering or centrifugally separating precipitates after the precipitation is finished, and drying at 80-150 ℃ to obtain a catalyst precursor;

(3) adding a binder into the catalyst precursor, preparing molded particles by adopting an extrusion molding method, an extrusion molding method or a rolling molding method, drying at 80-150 ℃, and roasting at 250-550 ℃ for 0.5-4h to obtain the nano composite nickel-based catalyst;

5. The method of preparing a nanocomposite nickel-based catalyst according to claim 4, characterized in that:

the soluble nickel salt is one or more of nickel acetate, nickel sulfate, nickel chloride and nickel nitrate;

the soluble salt of the first auxiliary agent is one or more of chloride, sub-chloride, nitrate, sub-nitrate, phosphate, sulfate, sub-sulfate and zirconium oxychloride of zirconium, iron and cobalt;

the soluble salt of the auxiliary agent II is one or more of chloride, nitrate, phosphate, sulfate, tungstate, metatungstate and molybdate of titanium, tin, tungsten, molybdenum and magnesium;

the precipitant is one or more of ammonium carbonate, ammonium bicarbonate, ammonia water, sodium hydroxide, sodium carbonate and sodium bicarbonate.

6. The method of preparing a nanocomposite nickel-based catalyst according to claim 3, characterized in that: the catalyst molding particles are spherical, granular, tooth-shaped, annular, flaky and strip-shaped, and the diameter, length and thickness of the molding particles are all 1-10 mm.

7. The method of claim 3, wherein the method comprises the steps of: the silica gel contains 10-50 wt% of silica, and the aluminum gel contains 5-20 wt% of aluminum oxide.

8. Use of the nanocomposite nickel-based catalyst according to claim 1 in hydrodesulfurization reactions of oils.

9. The use according to claim 8, wherein the reaction is a mercaptan-catalyzed thioetherification reaction in gasoline.

10. Use according to claim 9, characterized in that: the reaction is carried out in a fixed bed reactor, the reaction temperature is 80-150 ℃, the hydrogen pressure is 0.1-2MPa, the hydrogen-oil volume ratio is 100-10000, and the reaction space velocity is 0.1-10h^-1。