Nickel-based c4 fraction selective hydrogenation catalyst, preparation method and application thereof

Abstract

The application belongs to the technical field of hydrogenation catalysts, and particularly relates to a nickel-based C4 fraction selective hydrogenation catalyst, a preparation method and application thereof. The nickel-based C4 fraction selective hydrogenation catalyst is a Zn modified NiFe2O4 spinel solid solution, and a structural formula is Zn x Ni 1‑x Fe2O4, wherein 0.05<=x<=0.3. The application solves the problems of low butadiene conversion rate, high mono-olefin loss rate and high Pd-based catalyst cost in the existing non-noble metal catalytic system. The prepared nickel-based C4 fraction selective hydrogenation catalyst has low cost and high butadiene selective hydrogenation activity and mono-olefin yield when used in C4 fraction selective hydrogenation reaction.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of hydrogenation catalysts, and particularly relates to a nickel-based C4 fraction selective hydrogenation catalyst, a preparation method thereof and application thereof. BACKGROUND

[0002] The mixed C4 fraction of a refinery catalytic cracking unit is used as a raw material for an alkylation unit, which usually contains 1000-20000 ppm of butadiene. In the alkylation production process, the macromolecular hydrocarbons generated by the condensation of butadiene will dissolve in the acid phase to generate ASO (mixed acid-soluble oil), and will also react with the acid, and the product is sulfuric acid ester. This will have an adverse effect on the octane value of the light alkylation oil, increase the sulfur content of the alkylation oil, and reduce the dry point, and is a harmful impurity. Selective hydrogenation pretreatment of the alkylation raw material can convert the diene in the raw material into mono-olefin under the action of hydrogen and a catalyst, which can effectively limit the content of butadiene in the raw material to within the range of 100 ppm, thereby avoiding the dilution of sulfuric acid by the byproduct and affecting the acid consumption.

[0003] Currently, a liquid-phase fixed-bed selective hydrogenation process is used to remove butadiene from the raw material in the industry, and the selective hydrogenation catalyst is a supported Pd catalyst. However, the scarcity of Pd leads to high catalyst cost, which is not conducive to large-scale promotion in the early stage. Therefore, in recent years, researchers have conducted more extensive research on inexpensive non-noble metal alternative catalysts.

[0004] Patent CN105642324B discloses a preparation method of a 1,3-butadiene selective hydrogenation catalyst, which is composed of an active component amorphous nickel phosphide, an alumina carrier and an additive X. The catalyst preparation needs to undergo hydrothermal evaporation, inert atmosphere calcination, high-temperature hydrogen reduction and passivation processes. Under the conditions of 75-100℃, a total pressure of 1.5-2.0 MPa, a space velocity of 5-10 h -1 , and a hydrogen / butadiene molar ratio of 1.0-2.0, the butadiene conversion rate in the mixed C4 is >98%, and the butene loss rate is <1%.

[0005] CN106582706B discloses a preparation method of a nickel-based butadiene selective hydrogenation catalyst. The catalyst uses alumina as a carrier, and the main active component is Ni, and Ag, Au, Ce and K are used as the active component. The catalyst has good butadiene hydrogenation activity and low butene loss rate.

[0006] CN108404916A discloses a preparation method of a metal cobalt catalyst. Sodium hypophosphite is used as a reducing agent to directly synthesize the metal cobalt catalyst under normal pressure and low temperature. In the butadiene hydrogenation reaction, the butadiene conversion rate of the catalyst can reach 45.1%, and the 1-butene selectivity can reach 78.2%.

[0007] CN105399593A discloses a preparation method of Raney copper catalyst and is used for butadiene hydrogenation reaction, and the butadiene content in the mixed carbon four material after hydrogenation is >1000ppm, and the butene selectivity is about 76%.

[0008] CN104437522B discloses an alumina supported S modified Ni-based catalyst, and under the conditions that the reaction temperature is 40-90℃, the reaction pressure is 1.0-2.0MPa, the carbon four raw material volume space velocity is 3-20h -1 , and the hydrogen / hydrocarbon volume ratio is 2.0-4.0, about 260ppm of butadiene in the mixed carbon four is completely converted.

[0009] In the existing non-noble metal 1,3-butadiene selective hydrogenation reaction, the loading of non-noble metal is usually much higher than that of metal Pd catalyst, which will lead to the diversity and difference of the catalytic active sites, so that the over-hydrogenation reaction of 1-butene often accompanies the butadiene hydrogenation reaction, thereby reducing the yield of mono-olefin. By introducing metal or non-metal additives, the catalytic performance of the non-noble metal catalyst can be significantly improved. Although the Ag and Au modified Ni catalyst can improve the catalytic performance of Ni, it undoubtedly increases the cost of the catalyst and reduces the cost compared with the noble metal Pd catalyst. The preparation process of the P and S modified Ni-based catalyst is complicated, and the loss of non-metallic elements may contaminate the subsequent products and catalysts in the liquid phase carbon four selective hydrogenation reaction. SUMMARY

[0010] The purpose of the present application is to solve the problems of low butadiene conversion rate, high mono-olefin loss rate and high cost of Pd catalyst in the existing non-noble metal catalytic system in the prior art, and to provide a nickel-based carbon four fraction selective hydrogenation catalyst with low cost, high butadiene selective hydrogenation activity and high mono-olefin yield. The present application also provides a simple and easy preparation method and application in carbon four fraction selective hydrogenation reaction.

[0011] The nickel-based carbon four fraction selective hydrogenation catalyst according to the present application is a Zn modified NiFe2O4 spinel solid solution, and the structural formula is Zn x Ni 1-x Fe2O4, wherein 0.05≤x≤0.3.

[0012] The preparation method of the nickel-based carbon four fraction selective hydrogenation catalyst according to the present application comprises the following steps:

[0013] (1) dissolving nickel salt, zinc salt and iron salt precursors in deionized water to form a metal salt solution;

[0014] (2) dissolving a strong base in water to form a strong base solution;

[0015] (3) under the conditions of 25-80℃ and stirring, the strong base solution is added dropwise into the metal salt solution, the pH value is adjusted to 7-9, and the stirring is continued for 1-5h to obtain a mixed slurry;

[0016] (4) the mixed slurry is filtered and washed with deionized water until neutral, and then dried and calcined to obtain a catalyst intermediate;

[0017] (5) the catalyst intermediate and pseudo-boehmite are mixed according to a mass ratio of (3-5):1, then mixed with a citric acid aqueous solution, and then extruded into a strip, dried and calcined to obtain a nickel-based C4 fraction selective hydrogenation catalyst.

[0018] In step (1) of the present application, the molar ratio of Zn 2+ , Ni 2+ , and Fe 3+ contained in the zinc salt, nickel salt and iron salt is (0.05-0.3):(0.7-0.95):2.

[0019] In step (1) of the present application, the concentration of Fe 3+ in the metal salt solution is 0.5-1M.

[0020] In step (1) of the present application, the nickel salt is nickel nitrate, the zinc salt is zinc nitrate, and the iron salt is iron nitrate.

[0021] In step (2) of the present application, the strong base is NaOH, and the concentration of the strong base in the strong base solution is 1-2M.

[0022] In step (4) of the present application, the drying temperature is 60-120℃, the drying time is 10-24h, the calcination temperature is 400-800℃, and the calcination time is 4-10h.

[0023] In step (5) of the present application, in the citric acid aqueous solution, the concentration of citric acid is 5.9-8.3wt%.

[0024] In step (5) of the present application, the mass ratio of the sum of the mass of the catalyst intermediate and the mass of the pseudo-boehmite to the mass of citric acid is 80:1-120:1.

[0025] The nickel-based C4 fraction selective hydrogenation catalyst described in the present application is applied to a C4 fraction selective hydrogenation reaction.

[0026] Preferably, it is used for the selective hydrogenation of 1,3-butadiene in a C4 fraction to prepare 1-butene.

[0027] In one embodiment, the application process of the nickel-based C4 fraction selective hydrogenation catalyst is as follows:

[0028] In the presence of hydrogen, under the conditions of a reaction temperature of 30-80℃, a reaction pressure of 1.0-3.0 MPa, a reaction space velocity of 10-60 h-1, a hydrogen to 1,3-butadiene molar ratio of 0.2-10, the liquid phase carbon four is contacted with the nickel-based carbon four fraction selective hydrogenation catalyst in a fixed bed reactor to carry out a selective hydrogenation reaction, and 1-butene is prepared. -1 In the presence of hydrogen, under the conditions of a reaction temperature of 30-80℃, a reaction pressure of 1.0-3.0 MPa, a reaction space velocity of 10-60 h-1, a hydrogen to 1,3-butadiene molar ratio of 0.2-10, the liquid phase carbon four is contacted with the nickel-based carbon four fraction selective hydrogenation catalyst in a fixed bed reactor to carry out a selective hydrogenation reaction, and 1-butene is prepared.

[0029] Compared with the prior art, the present application has the following advantages:

[0030] The nickel-based carbon four fraction selective hydrogenation catalyst prepared by the present application has the advantages of low catalyst cost, low butene hydrogenation loss rate and low 1-butene isomerization rate in the reaction of selective hydrogenation removal of butadiene, and does not need to add additional noble metal additives and non-metal additives, the elements used in the catalyst are cheap and easy to obtain, and will not be lost in the selective hydrogenation reaction, causing pollution to downstream products, and is particularly suitable for pretreatment of raw materials of a sulfuric acid alkylation device. DETAILED DESCRIPTION

[0031] The present application will be further described below in conjunction with examples, but the protection scope of the present application is not limited thereto, and any changes to the technical solutions of the present application made by those skilled in the art shall fall within the protection scope of the present application.

[0032] In the examples, the raw materials used, unless otherwise specified, are all conventional commercially available raw materials; and the process methods used in the examples, unless otherwise specified, are all conventional methods in the art.

[0033] Example 1

[0034] The nickel-based carbon four fraction selective hydrogenation catalyst is prepared by the following method:

[0035] (1) Dissolve nickel nitrate, zinc nitrate and iron nitrate in deionized water to form a metal salt solution, wherein the Fe 3+ concentration is 0.5 M, the Zn 2+ , Ni 2+ , Fe 3+ molar ratio is 0.1:0.9:2;

[0036] (2) Dissolve NaOH in water to form a strong alkali solution with a NaOH concentration of 1 M;

[0037] (3) Under the condition of constant temperature of 60℃ and vigorous stirring, the strong alkali solution is added dropwise into the metal salt solution, the pH value is adjusted to 8, and the stirring is continued for 3 h to obtain a mixed slurry;

[0038] (4) The mixed slurry was filtered and washed with deionized water until neutral, dried at 120°C for 12 hours, and calcined at 500°C for 4 hours to obtain a catalyst intermediate;

[0039] (5) 50 g of the catalyst intermediate and pseudo-boehmite were mixed in a mass ratio of 3:1, and then mixed with 15 g of a 5.9 wt% citric acid aqueous solution. After extrusion into strips, the strips were dried at 60° C. for 24 h, and then calcined at 500° C. for 4 h to obtain a nickel-based C4 fraction selective hydrogenation catalyst.

[0040] Example 2

[0041] The nickel-based C4 fraction selective hydrogenation catalyst was prepared by the following method:

[0042] (1) Nickel nitrate, zinc nitrate and ferric nitrate are dissolved in deionized water to form a metal salt solution, in which Fe 3+ The concentration is 1.0M, Zn 2+ 、Ni 2+ 、Fe 3+ The molar ratio is 0.05:0.95:2;

[0043] (2) dissolving NaOH in water to form a strong alkaline solution with a NaOH concentration of 2 M;

[0044] (3) Under a constant temperature of 60°C and vigorous stirring, the strong base solution was added dropwise to the metal salt solution, the pH value was adjusted to 8.5, and stirring was continued for 2 h to obtain a mixed slurry;

[0045] (4) The mixed slurry was filtered and washed with deionized water until neutral, dried at 80°C for 12 h, and calcined at 500°C for 4 h to obtain a catalyst intermediate;

[0046] (5) 50 g of the catalyst intermediate and pseudo-boehmite were mixed in a mass ratio of 5:1, and then mixed with 10 g of a 6.8 wt% citric acid aqueous solution. After extrusion into strips, the strips were dried at 60°C for 12 h, and calcined at 500°C for 4 h to obtain a nickel-based C4 fraction selective hydrogenation catalyst.

[0047] Example 3

[0048] The nickel-based C4 fraction selective hydrogenation catalyst was prepared by the following method:

[0049] (1) Nickel nitrate, zinc nitrate and ferric nitrate are dissolved in deionized water to form a metal salt solution, in which Fe 3+ The concentration is 0.5M, Zn 2+ 、Ni 2+ 、Fe 3+ The molar ratio is 0.2:0.8:2;

[0050] (2) dissolving NaOH in water to form a strong alkaline solution with a NaOH concentration of 2 M;

[0051] (3) Under a constant temperature of 60°C and vigorous stirring, the strong base solution was added dropwise to the metal salt solution, the pH value was adjusted to 8.5, and stirring was continued for 2 h to obtain a mixed slurry;

[0052] (4) The mixed slurry was filtered and washed with deionized water until neutral, dried at 80°C for 12 h, and calcined at 500°C for 4 h to obtain a catalyst intermediate;

[0053] (5) 50 g of the catalyst intermediate and pseudo-boehmite were mixed in a mass ratio of 5:1, and then mixed with 10 g of a 7.0 wt% citric acid aqueous solution. After extrusion into strips, the strips were dried at 60°C for 12 h, and calcined at 500°C for 4 h to obtain a nickel-based C4 fraction selective hydrogenation catalyst.

[0054] Example 4

[0055] The nickel-based C4 fraction selective hydrogenation catalyst was prepared by the following method:

[0056] (1) Nickel nitrate, zinc nitrate and ferric nitrate are dissolved in deionized water to form a metal salt solution, in which Fe 3+ The concentration is 0.6M, Zn 2+ 、Ni 2+ 、Fe 3+ The molar ratio is 0.3:0.7:2;

[0057] (2) dissolving NaOH in water to form a strong alkaline solution with a NaOH concentration of 2 M;

[0058] (3) Under a constant temperature of 60°C and vigorous stirring, the strong base solution was added dropwise to the metal salt solution, the pH value was adjusted to 8.5, and stirring was continued for 3 h to obtain a mixed slurry;

[0059] (4) The mixed slurry was filtered and washed with deionized water until neutral, dried at 80°C for 12 h, and calcined at 500°C for 4 h to obtain a catalyst intermediate;

[0060] (5) 50 g of the catalyst intermediate and pseudo-boehmite were mixed in a mass ratio of 5:1, and then mixed with 8 g of an 8.3 wt% citric acid aqueous solution. After extrusion into strips, the strips were dried at 60°C for 12 h, and calcined at 500°C for 4 h to obtain a nickel-based C4 fraction selective hydrogenation catalyst.

[0061] Example 5

[0062] The nickel-based C4 fraction selective hydrogenation catalyst was prepared by the following method:

[0063] (1) nickel nitrate, zinc nitrate and iron nitrate were dissolved in deionized water to form a metal salt solution, wherein the molar ratio of Fe 3+ , Zn 2+ , Ni 2+ and Fe 3+ was 0.1:0.9:2, and the concentration of each metal ion was 0.6M;

[0064] (2) NaOH was dissolved in water to form a strong alkali solution with a NaOH concentration of 1M;

[0065] (3) the strong alkali solution was added dropwise into the metal salt solution under the condition of constant temperature at 80°C and intense stirring, the pH value was adjusted to 9, and the stirring was continued for 3h to obtain a mixed slurry;

[0066] (4) the mixed slurry was filtered and washed with deionized water until neutral, and then dried at 120°C for 12h and calcined at 500°C for 4h to obtain a catalyst intermediate;

[0067] (5) 50g of the catalyst intermediate and pseudo-boehmite were mixed according to a mass ratio of 5:1, and then mixed with 10g of a 7.0wt% citric acid aqueous solution, and then extruded into a strip, dried at 60°C for 12h, and calcined at 500°C for 4h to obtain a nickel-based C4 fraction selective hydrogenation catalyst.

[0068] Comparative Example 1

[0069] The nickel-based C4 fraction selective hydrogenation catalyst was prepared by the following method:

[0070] (1) nickel nitrate and iron nitrate were dissolved in deionized water to form a metal salt solution, wherein the molar ratio of Fe 3+ , Ni 2+ and Fe 3+ was 1:2, and the concentration of each metal ion was 0.6M;

[0071] (2) NaOH was dissolved in water to form a strong alkali solution with a NaOH concentration of 1M;

[0072] (3) the strong alkali solution was added dropwise into the metal salt solution under the condition of constant temperature at 80°C and intense stirring, the pH value was adjusted to 9, and the stirring was continued for 3h to obtain a mixed slurry;

[0073] (4) the mixed slurry was filtered and washed with deionized water until neutral, and then dried at 120°C for 12h and calcined at 500°C for 4h to obtain a catalyst intermediate;

[0074] (5) 50g of the catalyst intermediate and pseudo-boehmite were mixed according to a mass ratio of 5:1, and then mixed with 10g of a 7.0wt% citric acid aqueous solution, and then extruded into a strip, dried at 60°C for 12h, and calcined at 500°C for 4h to obtain a nickel-based C4 fraction selective hydrogenation catalyst.

[0075] The nickel-based carbon tetramer fraction selective hydrogenation catalysts prepared in Examples 1-5 and Comparative Example 1 were subjected to performance tests:

[0076] 15 mL of the nickel-based carbon tetramer fraction selective hydrogenation catalyst was packed in a fixed bed reactor, and selective hydrogenation of a catalytic C4 fraction containing 0.56% by mass of butadiene was carried out in a continuous manner. The composition of the C4 fraction is shown in Table 1, and the results of the selective hydrogenation performance evaluation of the catalyst are shown in Table 2. The operating conditions were as follows: reaction temperature 40°C, reaction pressure 1.5 MPa, feed weight hourly space velocity 10 h -1 , hydrogen / butadiene molar ratio 5:1.

[0077] Table 1 Composition of C4 fraction

[0078]

[0079] Table 2 Results of selective hydrogenation performance evaluation of catalyst

[0080] Catalyst Butadiene conversion / % Butadiene residual amount / ppm Butene loss / % Example 1 99.7 16.5 0.2 Example 2 99.6 22.3 0.3 Example 3 99.1 49.5 0.1 Example 4 99.3 38.5 0.1 Example 5 99.8 11.7 0.3 Comparative Example 1 93.6 358.4 0.1

Claims

1. A method for preparing a nickel-based C4 fraction selective hydrogenation catalyst, characterized in that: The following steps are involved: (1) Dissolving nickel salt, zinc salt and iron salt precursors in deionized water to form a metal salt solution; (2) Dissolve a strong base in water to form a strong base solution; (3) Add the strong base solution dropwise to the metal salt solution at a temperature of 25-80°C and under stirring conditions, adjust the pH value to 7-9, and continue stirring for 1-5 hours to obtain a mixed slurry; (4) filtering the mixed slurry and washing it with deionized water until it is neutral, and then drying and calcining it in sequence to obtain a catalyst intermediate; (5) The catalyst intermediate and pseudo-boehmite are mixed in a mass ratio of (3-5):1, and then mixed with a citric acid aqueous solution, extruded into strips, dried, and calcined to obtain a nickel-based C4 fraction selective hydrogenation catalyst; The nickel-based C4 fraction selective hydrogenation catalyst is a Zn-modified NiFe2O4 spinel solid solution with the structural formula Zn x Ni 1-x Fe2O4, where 0.05≤x≤0.

3.

2. The method for preparing a nickel-based C4 fraction selective hydrogenation catalyst according to claim 1, wherein: In step (1), the Zn contained in the zinc salt, nickel salt and iron salt 2+ 、Ni 2+ 、Fe 3+ The molar ratio is (0.05~0.3):(0.7~0.95):

2.

3. The method for preparing a nickel-based C4 fraction selective hydrogenation catalyst according to claim 1, wherein: In step (1), Fe 3+ The concentration is 0.5~1M.

4. The method for preparing a nickel-based C4 fraction selective hydrogenation catalyst according to claim 1, wherein: In step (1), nickel nitrate is used as the nickel salt, zinc nitrate is used as the zinc salt, and ferric nitrate is used as the iron salt.

5. The method for preparing a nickel-based C4 fraction selective hydrogenation catalyst according to claim 1, wherein: In step (2), the strong base is NaOH, and the concentration of the strong base in the strong base solution is 1~2M.

6. The method for preparing a nickel-based C4 fraction selective hydrogenation catalyst according to claim 1, wherein: In step (4), the drying temperature is 60-120°C, and the drying time is 10-24 hours; the roasting temperature is 400-800°C, and the roasting time is 4-10 hours.

7. The method for preparing a nickel-based C4 fraction selective hydrogenation catalyst according to claim 1, wherein: In step (5), the citric acid concentration in the citric acid aqueous solution is 5.9-8.3 wt %.

8. The method for preparing a nickel-based C4 fraction selective hydrogenation catalyst according to claim 1, wherein: In step (5), the mass ratio of the sum of the mass of the catalyst intermediate and the pseudo-boehmite to the mass of the citric acid is 80:1 to 120:

1.

9. Use of a nickel-based C4 fraction selective hydrogenation catalyst prepared by the preparation method according to any one of claims 1 to 8, characterized in that: Applied to the selective hydrogenation reaction of C4 fraction.

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