CN112657483B - Catalyst and preparation method thereof - Google Patents

Abstract

The present invention relates to the technical field of catalysts, more specifically, the present invention relates to a catalyst and a preparation method thereof. The preparation method of the catalyst comprises: impregnating the catalyst γ-Al ₂ O ₃ carrier into an active ingredient containing iron sulfate and nickel sulfate metal Put in the aqueous solution of the mixture, dry it in an oven after 10-48 hours, and then roast it again to obtain it. The preparation method of the catalyst of the present application is simple and easy to operate. At the same time, the prepared catalyst has high reaction activity and long-term activity stability. The catalyst obtained by using this method has a high conversion rate of propylene in the preparation process of propylene oligomers .

Description

A kind of catalyst and preparation method thereof

technical field

The invention relates to the technical field of catalysts, more specifically, the invention relates to a catalyst and a preparation method thereof.

Background technique

Long-chain olefins are very important chemical raw materials in petroleum refining and fine chemical production. The production of nonene and dodecene by oligomerization reaction using propylene as a raw material on a solid acid catalyst has attracted much attention in recent years, and the demand for the product has also increased sharply.

In the 1940s, the United States Universal Oil Company (UOP) developed the SPAC non-selective oligomerization process, which uses solid phosphoric acid-diatomaceous earth as a catalyst. This process is currently one of the most widely used olefin oligomerization processes in the world. The catalyst is cheap, has high surface activity and selectivity; and has the advantages of simple process flow, mature process technology, flexible raw materials and the like. Its main disadvantages are the low selectivity of the tetramer, the short service life of the catalyst, which is only 4 to 6 months and cannot be regenerated. During the reaction, the amount of water injected should be strictly controlled, otherwise the catalyst is easy to mud and agglomerate. The typical process of olefin oligomerization using zeolite molecular sieve as catalyst is the MOGD process developed by Mobil Corporation. The process uses medium-pore ZSM-5 molecular sieve (silicon/aluminum molar ratio is about 70) and Al ₂ O ₃ with a mass fraction of 35% to form a strip catalyst. The MOGD process is used for the oligomerization of C ₂ -C ₄ olefins. It has flexible processing schemes and less aromatics content in the product, but the process equipment and operation are more complicated, the reaction temperature is higher than that of solid phosphoric acid catalysts, and zeolite molecular sieve catalysts are prone to coking and deactivation , which is the main obstacle affecting the industrial implementation of this reaction process.

Contents of the invention

Aiming at some problems existing in the prior art, the first aspect of the present invention provides a method for preparing a catalyst, which includes: impregnating the γ-Al ₂ O ₃ carrier of the catalyst into a mixture containing iron sulfate and nickel sulfate metal active components In the aqueous solution, after 10-48h, place it in an oven to dry, and then roast it again to get it.

As a preferred technical solution of the present invention, the preparation method of the catalyst comprises the following steps:

(1) Calcining the catalyst gamma-Al ₂ O ₃ carrier to obtain a processed catalyst carrier;

(2) immersing the treated catalyst carrier into an aqueous solution containing a mixture of ferric sulfate and nickel sulfate metal active components, the immersion time is 10-48h;

(3) Dry the solid obtained in step (2) in an oven, and then roast again to obtain the product.

As a preferred technical solution of the present invention, the calcination temperature in the step (1) is 300-500°C.

As a preferred technical solution of the present invention, the calcination time in the step (1) is 1-10 hours.

As a preferred technical solution of the present invention, the volume ratio of the catalyst carrier treated in the step (2) to the aqueous solution containing the metal active component mixture is (1-2):1.

As a preferred technical solution of the present invention, the soaking time in the step (2) is 20-28 hours.

As a preferred technical solution of the present invention, the drying temperature in the oven in the step (3) is 80-150°C.

As a preferred technical solution of the present invention, the calcination temperature in the step (3) is 300-700°C.

As a preferred technical solution of the present invention, the calcination temperature in the step (3) is 400-650°C.

As a preferred technical solution of the present invention, the proportion of ferric ions in the metal active component mixture is nFe ³⁺ /n(Fe ³⁺ +Ni ²⁺ )=0.6˜0.95.

As a preferred technical solution of the present invention, the proportion of ferric ions in the metal active component mixture is nFe ³⁺ /n(Fe ³⁺ +Ni ²⁺ )=0.7.

The third aspect of the present invention provides a catalyst prepared according to the catalyst preparation method.

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

The preparation method of the catalyst of the present application is simple and easy to operate. At the same time, the prepared catalyst has high reaction activity and long-term activity stability. The catalyst obtained by using this method has a high conversion rate of propylene in the preparation process of propylene oligomers .

Detailed ways

The present invention is described below through specific embodiments, but not limited to the specific examples given below.

The first aspect of the present invention provides a method for preparing a catalyst, which includes: immersing the γ-Al ₂ O ₃ carrier of the catalyst in an aqueous solution containing a mixture of ferric sulfate and nickel sulfate metal active components for 10 to 48 hours, and then placing it in an oven Drying in medium temperature and roasting again, that is to say.

In one embodiment, the preparation method of the catalyst comprises the following steps:

(1) calcining the gamma- _Al2O3 carrier of _the catalyst to obtain a processed catalyst carrier;

(2) immersing the treated catalyst carrier into an aqueous solution containing a mixture of ferric sulfate and nickel sulfate metal active components, and the immersion time is 10 to 48 hours;

(3) Dry the solid obtained in step (2) in an oven, and then roast again to obtain the product.

step 1)

In one embodiment, the catalyst support is γ-Al ₂ O ₃ .

Preferably, the particle size of the γ-Al ₂ O ₃ is 1-100 mesh, the specific surface area is 120-350m ² /g, the average pore diameter is 8-20nm, and the average pore volume is 0.7-1.6mL/g; more preferably Specifically, the particle size of the γ-Al ₂ O ₃ is 80 mesh, the specific surface area is 302m ² /g, the average pore diameter is 12nm, and the average pore volume is 1.6mL/g.

In one embodiment, the calcination temperature in the step (1) is 300-500°C.

Preferably, the calcination temperature in the step (1) is 400°C.

In one embodiment, the calcination time in the step (1) is 1-10 hours.

Preferably, the calcination time in the step (1) is 3h.

step (2)

In one embodiment, the metal active component is a mixture of iron sulfate and nickel sulfate.

Preferably, the proportion of ferric ions in the metal active ingredient mixture nFe ³⁺ /n(Fe ³⁺ +Ni ²⁺ )=0.6～0.95; more preferably, the ferric iron in the metal active ingredient mixture The proportion of ions is nFe ³⁺ /n(Fe ³⁺ +Ni ²⁺ )=0.7.

In one embodiment, the volume ratio of the catalyst carrier treated in step (2) to the aqueous solution containing the metal active component mixture is (1-2):1.

Preferably, the volume ratio of the catalyst carrier treated in the step (2) to the aqueous solution containing the metal active component mixture is 1.7:1.

In one embodiment, the soaking time in step (2) is 20-28 hours.

Preferably, the soaking time in step (2) is 24h.

In the present application, the proportion of ferric ions in the metal active component is the molar proportion.

step (3)

In one embodiment, the drying temperature in the oven in the step (3) is 80-150°C.

Preferably, the drying temperature in the oven in the step (3) is 120°C.

In one embodiment, the drying time in the oven in the step (3) is 1-5 hours.

Preferably, the drying time in the oven in the step (3) is 2 hours.

In one embodiment, the calcination temperature in the step (3) is 300-700°C.

Preferably, the calcination temperature in the step (3) is 400-650°C; more preferably, the calcination temperature in the step (3) is 550°C.

In one embodiment, the calcination time in the step (3) is 2-6 hours.

Preferably, the calcination time in the step (3) is 4h.

The applicant unexpectedly found that drying the catalyst carrier, especially calcination at 300-500°C for 1-10 hours, can improve the conversion rate of propylene and the service life of the catalyst. The applicant believes that the possible reason is that under this condition , the metal active component mixture has a good loading capacity in the pores of the catalyst carrier and has a stable loading strength. At the same time, under this condition, some adsorbed water in the catalyst carrier can be effectively removed, reducing the acidity of the catalyst, and its propylene conversion rate is high. , and at the same time under this condition, the catalyst carrier can effectively combine with the metal active component, improving the conversion rate of propylene and the service life of the catalyst.

In addition, the applicant unexpectedly found that drying the catalyst carrier impregnated with the mixture of metal active components and then calcining at 300-700°C, especially 400-650°C, can increase the service life of the catalyst.

The second aspect of the present invention provides a catalyst prepared according to the catalyst preparation method.

In the catalyst obtained in the present application, the total amount of the mixture of iron sulfate and nickel sulfate accounts for 3-15 wt% of the catalyst.

Example

Hereinafter, the present invention is described in more detail through examples, but it should be understood that these examples are only illustrative and not restrictive. Unless otherwise stated, the raw materials used in the following examples are commercially available.

Example 1

Embodiment 1 of the present invention provides a kind of preparation method of catalyst, and its steps are as follows:

(1) Calcining γ-Al ₂ O ₃ at 300° C. for 10 h to obtain a treated catalyst carrier;

(2) Immerse the treated catalyst carrier into an aqueous solution containing a mixture of ferric sulfate and nickel sulfate metal active components for 10 hours, wherein the volume ratio of the catalyst carrier to the aqueous solution containing a mixture of metal active components is 1:1;

(3) Dry the solid obtained in step (2) in an oven at 80°C for 5 hours, and then bake it at 400°C for 6 hours to obtain the product.

The catalyst γ-Al ₂ O ₃ carrier has a particle size of 80 meshes, a specific surface area of 310 m ² /g, an average particle size of 10 nm, and an average pore volume of 0.89 mL/g.

In the iron sulfate and nickel sulfate metal active component mixture, the proportion of ferric ions is nFe ³⁺ /n(Fe ³⁺ +Ni ^{2 +} )=0.7.

The total amount of the mixture of iron sulfate and nickel sulfate accounts for 10wt% of the catalyst.

Example 2

Embodiment 2 of the present invention provides a kind of preparation method of catalyst, and its steps are as follows:

(1) Calcining the γ-Al ₂ O ₃ carrier at 500° C. for 1 hour to obtain a treated catalyst carrier;

(2) Immersing the treated catalyst carrier into an aqueous solution containing a mixture of ferric sulfate and nickel sulfate metal active components for 48 hours, wherein the volume ratio of the catalyst carrier to the aqueous solution containing a mixture of metal active components is 2:1;

(3) Dry the solid obtained in step (2) in an oven at 150°C for 1 hour, and then bake it at 650°C for 2 hours to obtain the product.

The catalyst γ-Al ₂ O ₃ carrier has a particle size of 80 meshes, a specific surface area of 310 m ² /g, an average particle size of 10 nm, and an average pore volume of 0.89 mL/g.

The proportion of ferric ions in the metal active component mixture of gold ferric sulfate and nickel sulfate is nFe ³⁺ /n(Fe ³⁺ +Ni ²⁺ )=0.7.

The total amount of the mixture of iron sulfate and nickel sulfate accounts for 7wt% of the catalyst.

Example 3

Embodiment 3 of the present invention provides a kind of preparation method of catalyst, and its steps are as follows:

(1) Calcining the catalyst γ-Al ₂ O ₃ carrier at 400° C. for 3 hours to obtain a treated catalyst carrier;

(2) Immerse the treated catalyst carrier into an aqueous solution containing a mixture of ferric sulfate and nickel sulfate metal active components for 24 hours, wherein the volume ratio of the catalyst carrier to the aqueous solution containing a mixture of metal active components is 1.7:1;

(3) Dry the solid obtained in step (2) in an oven at 120°C for 2 hours, and then bake it at 550°C for 4 hours to obtain the product.

The catalyst γ-Al ₂ O ₃ carrier has a particle size of 80 meshes, a specific surface area of 310 m ² /g, an average particle size of 10 nm, and an average pore volume of 0.89 mL/g.

The proportion of ferric ions in the iron sulfate and nickel sulfate metal active component mixture is nFe ³⁺ /n(Fe ³⁺ +Ni ^{2 +} )=0.7.

The total amount of the mixture of iron sulfate and nickel sulfate accounts for 8wt% of the catalyst.

Example 4

Embodiment 4 of the present invention provides a kind of preparation method of catalyst, it comprises the following steps:

(1) Immerse the treated catalyst gamma- _Al2O3 carrier into _an aqueous solution containing a mixture of ferric sulfate and nickel sulfate metal active components for 24 hours, wherein the volume ratio of the catalyst carrier to the aqueous solution containing a mixture of metal active components is 1.7:1;

(2) Dry the solid obtained in step (1) in an oven at 120°C for 2 hours, and then bake it at 550°C for 4 hours to obtain the product.

The total amount of the mixture of iron sulfate and nickel sulfate accounts for 8wt% of the catalyst.

Example 5

Embodiment 5 of the present invention provides a kind of preparation method of catalyst, and its specific embodiment is the same as embodiment 3, and difference is, described step (3) is that the solid that step (2) obtains is placed in 120 ℃ oven Dry for 2 hours, and then bake at 300°C for 4 hours to obtain it.

Example 6

Embodiment 6 of the present invention provides a kind of preparation method of catalyst, and its specific embodiment is the same as embodiment 3, and difference is that described step (3) is that the solid that step (2) obtains is placed in 120 ℃ oven Dry for 2 hours, and then bake at 700°C for 4 hours to obtain it.

Example 7

Embodiment 7 of the present invention provides a kind of preparation method of catalyst, and its specific implementation is the same as embodiment 3, and difference is that, described step (2) is that the catalyst support of processing is impregnated to the catalyst carrier containing ferric sulfate and nickel sulfate metal In the aqueous solution of the active ingredient mixture for 24 hours, wherein the volume ratio of the catalyst carrier and the aqueous solution containing the metal active ingredient mixture is 0.6:1.

Example 8

Embodiment 8 of the present invention provides a kind of preparation method of catalyst, and its specific implementation is the same as embodiment 3, and difference is, the catalyst support of processing is immersed in the aqueous solution containing ferric sulfate and nickel sulfate metal active ingredient mixture 32h , wherein the volume ratio of the catalyst carrier to the aqueous solution containing the mixture of metal active components is 1.7:1.

Example 9

Embodiment 9 of the present invention provides a kind of preparation method of catalyst, and its specific implementation is the same as embodiment 3, and difference is, the ratio nFe3 ⁺ / n(Fe ³⁺ +Ni ²⁺ )=0.5.

performance evaluation

1. Propylene conversion rate: respectively use the catalysts obtained in Examples 1 to 9 to produce propylene oligomers from propylene, which is specifically catalyzed at a reaction temperature of 67°C, a reaction pressure of 3.0 MPa, and a propylene flow rate of 1.2 L/h. get. After the propylene oligomer reaction is completed, the product is separated by the gas-liquid separator, and the tail gas is introduced into the chromatography for detection at any time, and the real-time propylene reaction conversion rate is calculated. Specifically: the composition of raw materials and reaction tail gas is analyzed using SP-6890 type chromatography, the analytical column is a special analytical column for dimethyl ether, the column temperature is 30°C, and a thermal conductivity cell detector is used. After the reaction liquid product is collected, use SP-6890 type chromatogram to analyze, the analytical column model of chromatogram is HP-PONA chromatographic column, FID detector. The column temperature starts to rise from 35°C, the temperature rise rate is 2°C/min, and the temperature program is raised to 270°C to stop. The data were processed using the N2000 ⁺ chromatographic data workstation, and the processing method was the area normalization method. The composition of each component in the liquid product was calculated from the peak area of each component.

2. Service life of the catalyst: Continuously use the catalyst obtained in Examples 1 to 9 for the production of propylene oligomers, record the conversion rate of propylene in each reaction time stage, and record the carbon numbers in Example 3 as 6, 9, and 12 , 15, 18 Selectivity of propylene oligomers.

See Table 1 for the propylene conversion ratios of the propylene oligomers produced using the catalysts obtained in Examples 1-9.

Table 1

Propylene conversion (wt%) Example 1 88.1 Example 2 74.2 Example 3 98.3 Example 4 93.3 Example 5 10.9 Example 6 60.1 Example 7 80.3 Example 8 78.1 Example 9 88.3

The catalysts obtained in Examples 1-9 were continuously used to produce propylene oligomers, and the propylene conversion rates in different reaction time periods are shown in Table 2.

Table 2

The catalyst obtained in Example 3 was continuously used to produce propylene oligomers, and the selectivity of propylene oligomers with different carbon numbers in different reaction time periods is shown in Table 2.

table 3

reaction time period C6 C9 C12 C15 C18 0-380h 8.1wt% 41.1wt% 32.2wt% 14.3wt% 4.3wt% 381-730h 10.3wt% 42.2wt% 32.6wt% 12.5wt% 2.4wt% 731-1260h 12.6wt% 40.0wt% 35.1wt% 10.3wt% 2.0wt% 1261-2000h 11.6wt% 41.8wt% 36.0wt% 9.2wt% 1.4wt%

The foregoing examples are illustrative only, and serve to explain some features of the methods described herein. The appended claims are intended to claim the broadest scope conceivable and the embodiments presented herein are merely illustrations of selected implementations according to all possible combinations of embodiments. Accordingly, it is the applicant's intention that the appended claims not be limited by the selection of examples which characterize the invention. Certain numerical ranges used in the claims also include sub-ranges therein, and changes within these ranges should also be construed as being covered by the appended claims where possible.

Claims (2)

1. a preparation method of catalyst, is characterized in that, comprises the following steps: (1) Calcining the catalyst γ-Al ₂ O ₃ carrier at 400°C for 3 hours to obtain the treated catalyst carrier; (2) Immerse the treated catalyst carrier in an aqueous solution containing a mixture of ferric sulfate and nickel sulfate metal active components for 24 hours; wherein, the volume ratio of the catalyst carrier to the aqueous solution containing a mixture of metal active components is 1.7:1; (3) Dry the solid obtained in step (2) in an oven at 120°C for 2 hours, and then roast at 550°C for 4 hours to obtain the product; The catalyst γ-Al ₂ O ₃ carrier has a particle size of 80 mesh, a specific surface area of 310m ² /g, an average particle size of 10nm, and an average pore volume of 0.89mL/g; The proportion of ferric ions in the iron sulfate and nickel sulfate metal active component mixture is nFe ³⁺ /n(Fe ³⁺ +Ni ²⁺ )=0.7. 2. A catalyst prepared according to the preparation method of the catalyst according to claim 1.