Supported nickel-based metal oxide catalyst as well as preparation method and application thereof

Abstract

The invention provides a supported nickel-based metal oxide catalyst as well as a preparation method and application thereof, and relates to the technical field of catalysts. The supported nickel-based metal oxide catalyst is obtained by sequentially carrying out steam treatment and drying on supported nickel-based metal oxide raw powder, the supported nickel-based metal oxide raw powder comprises an alumina carrier, and nickel oxide and gallium oxide which are supported on the alumina carrier; the temperature of the water vapor treatment is 150-550 DEG C. According to the invention, the supported nickel-based metal oxide raw powder is subjected to water vapor treatment at a certain temperature, so that the interaction between the active component of the catalyst and the carrier can be optimized and regulated, and the stability is improved; and the water vapor is used for treating the supported nickel-based metal oxide, so that the specific surface area is large, and high dispersion of active species is facilitated. The supported nickel-based metal oxide catalyst prepared by the invention is used in a reaction for preparing ethylene by oxidative dehydrogenation of ethane, and has good catalytic activity and stability.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and in particular to a supported nickel-based metal oxide catalyst and a preparation method and application thereof. Background Art

[0002] As we all know, the ethylene industry is an important petrochemical industry. Compared with the production of ethylene by naphtha cracking, the industry is more optimistic about the potential of ethane as a chemical raw material to produce ethylene, because ethane is not only more environmentally friendly than naphtha or its fractions, but also has great cost and investment advantages. Among the various routes for producing ethylene from ethane (ethane steam cracking, ethane direct dehydrogenation and ethane oxidative dehydrogenation), the ethane oxidative dehydrogenation process for producing ethylene has mild reaction conditions, low energy consumption, low equipment investment and operating costs. In the current context of resource conservation, it is considered to be a very promising ethylene production route.

[0003] At present, the technical research on ethane oxidative dehydrogenation to ethylene mainly focuses on the design and optimization of catalysts. Nickel-based metal oxide catalysts are considered to be the best choice for ethane oxidative dehydrogenation to ethylene because of their high CH bond cleavage activity under low temperature conditions and low cost. However, overall, the reaction performance of nickel-based metal oxide catalysts still has a lot of room for improvement, especially the catalytic stability is still poor. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a supported nickel-based metal oxide catalyst and its preparation method and application. The supported nickel-based metal oxide catalyst prepared by the present invention catalyzes the ethylene production reaction by oxidative dehydrogenation of ethane and has good stability.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for preparing a supported nickel-based metal oxide catalyst, comprising the following steps:

[0007] The supported nickel-based metal oxide raw powder is sequentially subjected to steam treatment and drying to obtain the supported nickel-based metal oxide catalyst;

[0008] The supported nickel-based metal oxide raw powder comprises an alumina carrier and nickel oxide and gallium oxide supported on the alumina carrier; the temperature of the water vapor treatment is 150-550°C.

[0009] Preferably, the weight percentage of nickel oxide in the supported nickel-based metal oxide raw powder is 7-15%, and the weight percentage of gallium oxide is 1-9%.

[0010] Preferably, the method for preparing the supported nickel-based metal oxide raw powder comprises the following steps:

[0011] After the aluminum oxide carrier is impregnated in a precursor solution, it is dried and calcined in sequence to obtain the supported nickel-based metal oxide raw powder; the precursor solution includes a soluble nickel salt and a soluble gallium salt.

[0012] Preferably, before the impregnation, the alumina carrier is pretreated at a temperature of 700° C. for 2 hours.

[0013] Preferably, the soluble nickel salt includes one or more of nickel nitrate, chloride, acetate and citrate, and the soluble gallium salt includes one or more of gallium nitrate, chloride, acetate and citrate.

[0014] Preferably, the impregnation time is 1 to 24 hours; the calcination temperature is 500 to 600° C., and the calcination time is 3 to 5 hours.

[0015] Preferably, the temperature of the water vapor treatment is 150°C, 250°C, 350°C, 450°C or 550°C.

[0016] Preferably, the water vapor treatment time is 1 to 3 hours.

[0017] The present invention provides a supported nickel-based metal oxide catalyst prepared by the preparation method described in the above technical scheme.

[0018] The present invention provides the use of the supported nickel-based metal oxide catalyst described in the above technical solution in the reaction of ethane oxidative dehydrogenation to produce ethylene.

[0019] The present invention provides a method for preparing a supported nickel-based metal oxide catalyst, comprising the following steps: subjecting a supported nickel-based metal oxide raw powder to steam treatment and drying in sequence to obtain the supported nickel-based metal oxide catalyst; the supported nickel-based metal oxide raw powder comprises an alumina carrier and nickel oxide and gallium oxide supported on the alumina carrier; the steam treatment temperature is 150-550°C. The present invention subjects the supported nickel-based metal oxide raw powder to steam treatment at a certain temperature, which can optimize and regulate the interaction between the active components of the catalyst and the carrier, so that the catalyst has an appropriate content of isolated Ni 2+ species and Ni with strong metal-support interactions 2+ The supported nickel-based metal oxide catalyst prepared by the present invention is used in the ethylene oxidative dehydrogenation reaction of ethane to produce ethylene, and has good catalytic activity and stability.

[0020] The results of the embodiment show that compared with the supported nickel-based metal oxide catalyst that has not been treated with water vapor, the supported nickel-based metal oxide catalyst obtained by water vapor treatment in the present invention has better catalytic stability, and the ethylene yield decreases less after 24 hours of ethane oxidative dehydrogenation reaction to produce ethylene. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 These are the H2-TPR characterization results of the catalysts obtained in Examples 1 to 5 and Comparative Example 1. DETAILED DESCRIPTION

[0022] The present invention provides a method for preparing a supported nickel-based metal oxide catalyst, comprising the following steps:

[0023] The supported nickel-based metal oxide raw powder is sequentially subjected to steam treatment and drying to obtain the supported nickel-based metal oxide catalyst;

[0024] The supported nickel-based metal oxide raw powder comprises an alumina carrier and nickel oxide and gallium oxide supported on the alumina carrier; the temperature of the water vapor treatment is 150-550°C.

[0025] In the present invention, unless otherwise specified, the raw materials involved are commercially available products well known in the art.

[0026] First, the supported nickel-based metal oxide raw powder will be described.

[0027] In the present invention, the supported nickel-based metal oxide raw powder includes an alumina carrier and nickel oxide and gallium oxide supported on the alumina carrier, wherein nickel oxide is an active component and gallium is a doping component that acts as a promoter, which affects the acidity of the catalyst and regulates the interaction between the carrier and the active component; the chemical formula of the supported nickel-based metal oxide raw powder can be expressed as NiMO / Al2O3, wherein M is Ga. In the present invention, in the supported nickel-based metal oxide raw powder, the mass percentage of nickel oxide is preferably 7-15%, more preferably 12-13%, and further preferably 12.7-12.9%, and the mass percentage of gallium oxide is preferably 1-9%, more preferably 3-5%, and further preferably 3.2-4.2%.

[0028] In the present invention, the method for preparing the supported nickel-based metal oxide raw powder preferably comprises the following steps:

[0029] After the aluminum oxide carrier is impregnated in a precursor solution, it is dried and calcined in sequence to obtain the supported nickel-based metal oxide raw powder; the precursor solution includes a soluble nickel salt and a soluble gallium salt.

[0030] The present invention adopts a wet impregnation method to prepare the supported nickel-based metal oxide raw powder.

[0031] In the embodiment of the present invention, the alumina carrier is preferably γ-Al2O3, and the specific surface area is preferably 152m 2 ·g -1 In the present invention, before the impregnation, the alumina carrier is preferably pretreated, the pretreatment temperature is preferably 700°C, the time is preferably 2 hours, and the pretreatment is preferably carried out in an air atmosphere; the role of the pretreatment is to remove impurities adsorbed on the surface of the alumina carrier.

[0032] In the present invention, the precursor solution (i.e., the impregnation solution) includes a soluble nickel salt and a soluble gallium salt, specifically, the soluble nickel salt and the soluble gallium salt are dissolved in water; the soluble nickel salt preferably includes one or more of nickel nitrate, chloride, acetate and citrate, preferably nitrate, and the soluble gallium salt preferably includes one or more of gallium nitrate, chloride, acetate and citrate, preferably nitrate. In an embodiment of the present invention, the soluble nickel salt and the soluble gallium salt are nickel nitrate (Ni(NO3)2·6H2O) and gallium nitrate (Ga(NO3)3·xH2O), respectively. In the present invention, the mass content of the soluble nickel salt in the precursor solution is preferably 3.9-7.9%, more preferably 4.9-6.9%, the mass content of the soluble gallium salt is 0.5-3.5%, more preferably 1.2-2.5%, and the mass ratio of the precursor solution to the alumina carrier is preferably 8.7-9:1.

[0033] In the present invention, the impregnation time is preferably 1 to 24 hours, more preferably 20 to 24 hours. The impregnation can be carried out at room temperature. The present invention preferably places the alumina carrier in the precursor solution and carries out the impregnation under stirring. In the present invention, the drying preferably includes infrared drying and oven drying in sequence. The infrared drying is preferably carried out under stirring. The infrared drying promotes the volatilization of the impregnation solution (impregnation is also carried out during this process); the oven drying temperature is preferably 120 to 200°C, more preferably 120 to 150°C, and the time is preferably 1 to 24 hours, more preferably 20 to 24 hours. In the present invention, the calcination temperature is preferably 500 to 600°C, more preferably 550°C, and the time is preferably 3 to 5 hours, more preferably 4 hours; the calcination is preferably carried out in an air atmosphere. During the calcination process, the nickel salt and gallium salt on the alumina carrier are oxidized to the corresponding oxides, and an ion substitution effect may occur, such as Ni 2+ Substitute Al in Al2O3 lattice 3+ ; In addition, it may also enhance the interaction between the oxide and the alumina support, such as enhancing the interaction between NiO and the alumina support.

[0034] The preparation of the supported nickel-based metal oxide catalyst is described below.

[0035] In the present invention, the temperature of the water vapor treatment is preferably 150-550°C, specifically 150, 250, 350, 450, 550°C; the time of the water vapor treatment is preferably 1-3h, specifically 1, 2, 3h. In the present invention, the specific operation of the water vapor treatment is preferably: loading the supported nickel-based metal oxide raw powder into a fixed bed to form a catalyst bed, and passing water vapor with a temperature of 150-550°C into the catalyst bed for water vapor treatment.

[0036] In the present invention, water vapor treatment at different temperatures will affect the interaction between the active component and the carrier, change the redox property of the catalyst, and further affect the catalytic activity and stability, wherein water vapor treatment at a lower temperature is conducive to the formation of NiO species that do not interact with the carrier, and water vapor treatment at a higher temperature is conducive to the formation of NiAl2O4 spinel structures, and will also affect the Lewis acidity on the catalyst. The present invention treats the supported nickel-based metal oxide raw powder with water vapor at a certain temperature, especially when the water vapor treatment temperature reaches above 450°C, the interaction between the active component and the carrier is enhanced, which is conducive to stabilizing the active component and improving its catalytic stability.

[0037] In the present invention, the drying temperature is preferably the same as the steam treatment temperature, and the drying time is preferably 3 hours. After the steam treatment, there are a lot of physically adsorbed water or hydroxyl groups on the catalyst surface, which may affect the reaction, so the drying is required.

[0038] The preparation method provided by the invention is simple and easy to control, and can be easily scaled up for preparation.

[0039] The present invention provides a supported nickel-based metal oxide catalyst prepared by the preparation method described in the above technical solution. In an embodiment of the present invention, the supported nickel-based metal oxide catalyst is represented by NiMO / Al2O3-T, wherein T corresponds to the temperature of the water vapor treatment. The supported nickel-based metal oxide catalyst provided by the present invention is treated with water vapor, and the interaction between the active component and the carrier is optimized and regulated. In an embodiment of the present invention, the specific surface area of ​​the supported nickel-based metal oxide catalyst is 104 to 118 m 2 ·g -1 The supported nickel-based metal oxide catalyst provided by the present invention has a large specific surface area, promotes high dispersion of active components and interaction between different components.

[0040] The present invention provides the use of the supported nickel-based metal oxide catalyst in the above technical solution in the ethylene oxidation dehydrogenation reaction of ethane. In the present invention, the feed gas of the ethylene oxidation dehydrogenation reaction of ethane comprises ethane, oxygen and nitrogen, and the volume ratio of ethane, oxygen and nitrogen is preferably 6:6:88; the temperature of the ethylene oxidation dehydrogenation reaction of ethane is preferably 450°C, and the pressure is preferably normal pressure. The supported nickel-based metal oxide catalyst is used in the ethylene oxidation dehydrogenation reaction of ethane, and has good catalytic activity and stability.

[0041] In order to further illustrate the present invention, the supported nickel-based metal oxide catalyst provided by the present invention and its preparation method and application are described in detail below in conjunction with examples, but they should not be construed as limiting the scope of protection of the present invention.

[0042] In each embodiment, Al2O3 is γ-Al2O3 with a specific surface area of ​​152m 2 ·g -1 .

[0043] Comparative Example 1

[0044] Pre-treat 10g Al2O3 in air at 700℃ for 2h. In a beaker, dissolve 1.5g Ni(NO3)2·6H2O and 0.263g Ga(NO3)3·xH2O (molecular weight 255.74) in 20mL water at 25℃ and stir to prepare a precursor solution. Place the pre-treated 2.5g Al2O3 in the above precursor solution, stir for 24h, and then infrared dry (keep stirring) into powder, then dry in an oven at 120℃ for 24h, and calcine at 550℃ for 4h to obtain NiGaO / Al2O3 catalyst raw powder. The specific surface area of ​​the catalyst is 135m 2 ·g -1 According to ICP measurement, the content of NiO, Ga2O3 and Al2O3 in the catalyst is 12.7wt%, 4.2wt% and 83.1wt%.

[0045] Example 1

[0046] Pre-treat 10gAl2O3 in air at 700℃ for 2h. In a beaker, dissolve 1.5gNi(NO3)2·6H2O and 0.263gGa(NO3)3·xH2O (molecular weight 255.74) in 20mL water at 25℃ and stir to prepare a precursor solution. Place the pre-treated 2.5gAl2O3 in the above precursor solution, stir for 24h, and then dry under an infrared lamp (keep stirring) to powder, then dry in an oven at 120℃ for 24h, and calcine at 550℃ for 4h to obtain NiGaO / Al2O3 catalyst raw powder.

[0047] The prepared NiGaO / Al2O3 catalyst powder was loaded into a fixed bed to form a catalyst bed. Water was preheated to steam at 150°C at a flow rate of 0.5 mL / min by a peristaltic pump and then entered the catalyst bed for steam treatment. After steam treatment for 1 hour, it was dried at 150°C for 3 hours to obtain a NiGaO / Al2O3-150 catalyst. The specific surface area of ​​the catalyst is 112 m 2 ·g -1 .

[0048] Example 2

[0049] Pre-treat 10gAl2O3 in air at 700℃ for 2h. In a beaker, dissolve 1.5g Ni(NO3)2·6H2O and 0.263gGa(NO3)3·xH2O in 20mL water at 25℃ and stir to prepare a precursor solution. Place the pre-treated 2.5gAl2O3 in the above precursor solution, stir for 24h, and then infrared dry (keep stirring) to powder, then dry in an oven at 120℃ for 24h, and calcine at 550℃ for 4h to obtain NiGaO / Al2O3 catalyst raw powder.

[0050] The prepared NiGaO / Al2O3 catalyst powder was treated with 250°C steam for 1 hour (the specific operation is the same as in Example 1), and then dried at 250°C for 3 hours to obtain NiGaO / Al2O3-250 catalyst. The specific surface area of ​​the catalyst is 118 m 2 ·g -1 .

[0051] Example 3

[0052] Pre-treat 10gAl2O3 in air at 700℃ for 2h. In a beaker, dissolve 1.5g Ni(NO3)2·6H2O and 0.263gGa(NO3)3·xH2O in 20mL water at 25℃ and stir to prepare a precursor solution. Place the pre-treated 2.5gAl2O3 in the above precursor solution, stir for 24h, and then infrared dry (keep stirring) to powder, then dry in an oven at 120℃ for 24h, and calcine at 550℃ for 4h to obtain NiGaO / Al2O3 catalyst raw powder.

[0053] The prepared NiGaO / Al2O3 catalyst powder was treated with 350°C steam for 1 hour (the specific operation was the same as in Example 1), and then dried at 350°C for 3 hours to obtain a NiGaO / Al2O3-350 catalyst. The specific surface area of ​​the catalyst was 104m 2 ·g -1 .

[0054] Example 4

[0055] Pre-treat 10gAl2O3 in air at 700℃ for 2h. In a beaker, dissolve 1.5g Ni(NO3)2·6H2O and 0.263gGa(NO3)3·xH2O in 20mL water at 25℃ and stir to prepare a precursor solution. Place the pre-treated 2.5gAl2O3 in the above precursor solution, stir for 24h, and then infrared dry (keep stirring) to powder, then dry in an oven at 120℃ for 24h, and calcine at 550℃ for 4h to obtain NiGaO / Al2O3 catalyst raw powder.

[0056] The prepared NiGaO / Al2O3 catalyst powder was treated with 450°C steam for 1 hour (the specific operation was the same as in Example 1), and then dried at 450°C for 3 hours to obtain a NiGaO / Al2O3-450 catalyst. The specific surface area of ​​the catalyst was 106m 2 ·g -1 .

[0057] Example 5

[0058] Pre-treat 10gAl2O3 in air at 700℃ for 2h. In a beaker, dissolve 1.5g Ni(NO3)2·6H2O and 0.263gGa(NO3)3·xH2O in 20mL water at 25℃ and stir to prepare a precursor solution. Place the pre-treated 2.5gAl2O3 in the above precursor solution, stir for 24h, and then infrared dry (keep stirring) to powder, then dry in an oven at 120℃ for 24h, and calcine at 550℃ for 4h to obtain NiGaO / Al2O3 catalyst raw powder.

[0059] The prepared NiGaO / Al2O3 catalyst powder was treated with 550°C steam for 1 hour (the specific operation was the same as in Example 1), and then dried at 550°C for 3 hours to obtain a NiGaO / Al2O3-550 catalyst. The specific surface area of ​​the catalyst was 117 m 2 ·g -1 .

[0060] Example 6

[0061] Pre-treat 10gAl2O3 in air at 700℃ for 2h. In a beaker, dissolve 1.5g Ni(NO3)2·6H2O and 0.263gGa(NO3)3·xH2O in 20mL water at 25℃ and stir to prepare a precursor solution. Place the pre-treated 2.5gAl2O3 in the above precursor solution, stir for 24h, and then infrared dry (keep stirring) to powder, then dry in an oven at 120℃ for 24h, and calcine at 550℃ for 4h to obtain NiGaO / Al2O3 catalyst raw powder.

[0062] The prepared NiGaO / Al2O3 catalyst powder was treated with 350°C steam for 3 hours (the specific operation is the same as in Example 1), and then dried at 350°C for 3 hours to obtain a NiGaO / Al2O3-350-3h catalyst. The specific surface area of ​​the catalyst is 125m 2 ·g -1 .

[0063] The catalysts obtained in Examples 1 to 6 and Comparative Example 1 were applied to the ethylene production reaction by oxidative dehydrogenation of ethane. The specific evaluation process is as follows:

[0064] 0.5g of quartz sand was spread on the lower layer of the reaction tube, 0.5g of the tabletted catalyst was taken and filled, and 0.3g of quartz sand was spread on the upper layer of the catalyst. The reaction conditions were: temperature of 450°C, atmospheric pressure, the volume ratio of raw gas ethane: oxygen: nitrogen was 6:6:88, and the total flow rate was 62.5mL / min. When the reactor temperature, gas flow rate, etc. were stable (1h), the ethane conversion rate, ethylene selectivity and yield at different reaction times were measured by sampling and analysis, and the results are shown in Table 1.

[0065] Table 1 Catalytic performance evaluation results of the catalysts obtained in Examples 1 to 6 and Comparative Example 1

[0066]

[0067] As shown in Table 1, when the catalysts obtained in Examples 1 to 6 and Comparative Example 1 are used to catalyze the oxidative dehydrogenation of ethane to produce ethylene, there are differences in conversion rate, selectivity, yield and stability. The catalysts in Examples 1 to 6 have a lower ethylene yield decrease rate than the catalyst in Comparative Example 1, indicating that the stability of the supported nickel-based metal oxide is improved by steam treatment.

[0068] Figure 1 The H2-TPR characterization results of the catalysts obtained in Examples 1 to 5 and Comparative Example 1 are given. It can be seen that the steam treatment of supported nickel-based metal oxides at different temperatures will affect the interaction between the active components and the support. 2+ (NiO) species and Ni with strong metal-support interactions 2+ Species (NiAl bonded to NiO, some Al incorporated into the NiO lattice 2-x O4 and NiAl2O4), changing the redox properties of the catalyst, thus affecting the catalytic activity and stability. As shown in Table 2, with the increase of steam treatment temperature, the isolated Ni 2+ The content of the species gradually decreased, and Ni with strong metal-support interaction 2+The species content gradually increases, especially when the water vapor treatment temperature reaches above 450°C, the interaction between the active components and the carrier is greatly enhanced, which is beneficial to stabilize the active components and improve their catalytic stability.

[0069] Table 2 Ni on the catalyst surface in Examples 1 to 5 and Comparative Example 1 2+ Relative content of species

[0070] catalyst <![CDATA[Isolated Ni 2+ Species (%)]]> <![CDATA[Ni with strong metal-support interaction 2+ Species (%)]]> Comparative Example 1 6.0％ 94.0％ Example 1 7.9％ 92.1％ Example 2 7.6％ 92.4％ Example 3 6.6％ 93.4％ Example 4 4.0％ 96.0％ Example 5 4.3％ 95.7％

[0071] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a supported nickel-based metal oxide catalyst, characterized in that: The following steps are involved: The supported nickel-based metal oxide raw powder is sequentially subjected to steam treatment and drying to obtain the supported nickel-based metal oxide catalyst; The supported nickel-based metal oxide raw powder comprises an alumina carrier and nickel oxide and gallium oxide supported on the alumina carrier; the temperature of the water vapor treatment is 150-550°C.

2. The preparation method according to claim 1, characterized in that: The mass percentage of nickel oxide in the supported nickel-based metal oxide raw powder is 7-15%, and the mass percentage of gallium oxide is 1-9%.

3. The preparation method according to claim 1 or 2, characterized in that: The method for preparing the supported nickel-based metal oxide raw powder comprises the following steps: After the aluminum oxide carrier is impregnated in a precursor solution, it is dried and calcined in sequence to obtain the supported nickel-based metal oxide raw powder; the precursor solution includes a soluble nickel salt and a soluble gallium salt.

4. The preparation method according to claim 3, characterized in that: Before the impregnation, the alumina carrier is pretreated at a temperature of 700° C. for 2 hours.

5. The preparation method according to claim 3, characterized in that: The soluble nickel salt includes one or more of nickel nitrate, chloride, acetate and citrate, and the soluble gallium salt includes one or more of gallium nitrate, chloride, acetate and citrate.

6. The preparation method according to claim 3, characterized in that: The impregnation time is 1 to 24 hours; the calcination temperature is 500 to 600° C. and the calcination time is 3 to 5 hours.

7. The preparation method according to claim 1, characterized in that: The temperature of the water vapor treatment is 150°C, 250°C, 350°C, 450°C or 550°C.

8. The preparation method according to claim 1 or 7, characterized in that: The water vapor treatment time is 1 to 3 hours.

9. The supported nickel-based metal oxide catalyst prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the supported nickel-based metal oxide catalyst according to claim 9 in the oxidative dehydrogenation of ethane to produce ethylene.

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