A nickel catalyst prepared by spin-enhanced impregnation and a spin-enhanced impregnation device

Abstract

This invention relates to the field of catalysts, specifically to a nickel catalyst prepared by rotation-enhanced impregnation and its preparation method. Addressing the problems of low dispersion and large particle size of active components in supported catalysts prepared by traditional impregnation methods, and the tendency for the support to break down in conventional hypergravity beds, this invention provides a rotation-enhanced impregnation method incorporating a support ring. The alumina support rotates slowly alongside the support ring, and the impregnation liquid forms a mist or droplets under centrifugal force, spraying onto the rotating support surface at extremely high speeds. Finally, after drying and calcination, a catalyst with high nickel dispersion is obtained, effectively avoiding support breakage during the impregnation process.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, specifically relating to a nickel catalyst prepared by rotational enhanced impregnation and a rotational enhanced impregnation apparatus. Background Technology

[0002] Generally, industrial catalysts are mainly composed of catalytically active components, promoters, and supports. Among them, the dispersion of catalytically active components directly affects the catalytic activity of the catalyst. Impregnation is a commonly used method for catalyst preparation in industry. The main process is to soak the support in a solution containing the active components. Sometimes the supported components are impregnated with vapor phase, which is called vapor phase impregnation. After the support and active components are in contact for a period of time, the remaining liquid is removed by filtration, evaporation, etc. The active components are loaded on the surface of the support in the form of microcrystals of ions or compounds. Then, the catalyst is activated by drying, calcination, etc., to obtain the final catalyst product. The main characteristics of the impregnation method are: (1) It can use a support with a pre-existing shape and size, without the need for subsequent catalyst forming operations; (2) The impregnation method can load one or more active components on the support; (3) The pore structure of the support basically determines the pore structure and specific surface area of ​​the catalyst. However, the traditional impregnation method has disadvantages such as long impregnation equilibrium time, low impregnation amount, and unevenness.

[0003] A centrifugal rotating packed bed is a chemical intensification device that can highly enhance micro-mixing and mass transfer. In a centrifugal environment, the enormous shear force generated by the rotation of the packing material shears the fluid into extremely small liquid micro-elements, increasing the phase contact area and significantly improving the mixing and mass transfer effects between phases. The mass transfer coefficient is 10-1000 times higher than that of conventional reactors. Therefore, the centrifugal rotating intensified impregnation method can improve the dispersion of catalytically active components and enhance catalytic performance.

[0004] Chinese patent CN108854931A discloses a method for preparing a catalyst, which involves two steps: impregnation and activation, performed in a rotating packed bed under high gravity. The impregnation process primarily involves loading a metal ion solution onto a support, while the activation process involves drying and activating the impregnated support in a high-temperature gas environment. This patent solves the problems of long preparation time and low impregnation content associated with conventional impregnation methods. However, this patent uses a support as the packing material in the rotating packed bed. During preparation, the support packing material will be subjected to enormous centrifugal force, interacting with the fixed filter membrane, leading to significant catalyst breakage during production, which is detrimental to industrial-scale production.

[0005] Chinese patent CN110302797A discloses a method for preparing a supported catalyst. It uses a cross-flow rotating packed bed as a hypergravity device, Al₂O₃ as the packing material, and a mixed solution of metal salts as the impregnation liquid. Under hypergravity, the impregnation liquid is sprayed onto the surface of the support. The impregnated liquid is then returned to a storage tank for recirculation. Hot air is used to blow off the packing material and remove surface moisture from the precursor. The catalyst is then calcined at 300-700℃ to obtain a two-component manganese-based supported catalyst. However, this method also suffers from the problem of catalyst breakage due to the support packing material being subjected to enormous centrifugal force.

[0006] Chi Ma et al. (Mass transfer intensification mechanism of Al2O3 sphere packing in a rotating packed bed, Chemical Engineering Journal) studied solution impregnation using Al2O3 as the direct filler. During rotation, the alumina carriers were squeezed together by centrifugal force, causing their positions to remain unchanged. As a result, only a fixed portion of the alumina carriers were impregnated by the impregnation solution during spraying, leading to uneven particle impregnation. Summary of the Invention

[0007] To address the problems of existing traditional impregnation methods and hypergravity impregnation methods, this invention provides a method for preparing nickel catalysts by rotation-enhanced impregnation, which avoids the problem of support breakage.

[0008] One objective of this invention is to provide a method for preparing a nickel catalyst, comprising: using a rotation-enhanced impregnation apparatus, using a solution containing metallic nickel salt and auxiliary metallic salt as an impregnation liquid, placing an alumina support in a rotatable support ring, spraying the impregnation liquid onto the rotating alumina support under centrifugal force, and drying and calcining to obtain the nickel catalyst.

[0009] According to an embodiment of the present invention, the preparation method specifically includes the following steps:

[0010] Step 1: Load the alumina carrier into the carrier ring, pump the mixed salt solution containing nickel salt and auxiliary metal salt into the rotary strengthening impregnation device, and spray it evenly into the inside of the rotary packing through the liquid distributor.

[0011] Step 2: Under the action of centrifugal force, the mixed salt solution is sheared into tiny liquid micro-elements by the rotating packing material, which come into contact with the alumina support in the low-speed rotating support ring, thereby enhancing the impregnation and obtaining the nickel catalyst precursor.

[0012] Step 3: Dry and calcine the nickel catalyst precursor obtained in Step 2 to obtain the nickel catalyst.

[0013] In the above preparation method, the specific surface area of ​​the alumina support is 100~300m². 2 / g, pore volume of 0.5~1.5m 3 / g, preferably, the specific surface area of ​​the alumina carrier is 140~250m² / g. 2 / g, pore volume 0.7~1.2m 3 / g. The alumina carrier used in this invention can be a shaped alumina carrier, which can be obtained by processing commercially available alumina, as long as the obtained alumina carrier meets the above-mentioned specific surface area and pore volume requirements. Specifically, the processing method for commercially available alumina can be drying at 100~120℃ for 2~10h and calcining at 400~600℃ for 2~10h. According to a preferred embodiment of this invention, the shaped alumina carrier produced by the Beijing Chemical Research Institute is optimal.

[0014] In the above preparation method, the nickel salt can be a water-soluble nickel salt or a nickel salt soluble in acid, preferably selected from at least one of nickel nitrate, nickel sulfate, and basic nickel carbonate; the auxiliary metal salt is selected from at least one of magnesium, calcium, lanthanum, barium, and cerium metal salts, preferably selected from at least one of magnesium, calcium, lanthanum, barium, and cerium nitrate, sulfate, or carbonate.

[0015] According to an embodiment of the present invention, in step one:

[0016] In the mixed salt solution, the mass percentage concentration of metallic nickel is 1-15%, preferably 5-15%;

[0017] In the mixed salt solution, the mass percentage concentration of the auxiliary metal is 0.01-5%, preferably 0.1-1%;

[0018] The rotating packing is a wire mesh or a cylindrical packing. The rotating packing used in this invention can be a wire mesh or cylindrical packing commonly used in rotating beds in the art, such as stainless steel wire mesh or fixed stainless steel cylindrical packing.

[0019] According to an embodiment of the present invention, in step two: the rotational speed of the rotating packing is 1000~2000 rpm; the rotational speed of the carrier ring is 10~20 rpm; and the strengthening impregnation time is 10~30 min. The rotating packing and the carrier ring can rotate in the same direction or in opposite directions, as long as the rotating packing rotates at high speed and the carrier ring rotates at low speed.

[0020] According to an embodiment of the present invention, in step three: the drying and calcination can be carried out using commonly used drying or calcination equipment and commonly used drying or calcination conditions. Preferably, the drying conditions are drying at 100~120℃ for 2~10 hours; the calcination conditions are calcination at 400~600℃ for 2~10 hours.

[0021] According to a preferred embodiment of the present invention, the specific preparation steps of the nickel catalyst are as follows:

[0022] (1) Impregnation step: After the alumina support is treated, it is loaded into the wire mesh support ring. The mixed metal salt impregnation solution containing nickel salt and auxiliary metal salt is pumped into the rotary enhanced impregnation device and sprayed evenly into the inner edge of the rotary packing through the liquid distributor. Under the action of high-speed centrifugal force, the impregnation solution is sheared into tiny liquid micro-elements by the rotary packing and comes into contact with the alumina support in the support ring with extremely high tangential initial velocity. The support ring rotates at low speed to ensure that the support and the impregnated liquid micro-elements are in full contact. The impregnated liquid is returned to the storage tank for liquid circulation. After a certain impregnation time, the nickel catalyst precursor is obtained.

[0023] (2) Drying and calcination steps: The nickel catalyst precursor is dried and calcined to decompose it;

[0024] (3) Repeat steps (1) and (2) as needed for the metal content in the actual catalyst until the final nickel catalyst is obtained.

[0025] A second objective of this invention is to provide a nickel catalyst prepared by the above-described preparation method.

[0026] According to an embodiment of the present invention, the nickel catalyst comprises the following components, based on 100% of its total weight:

[0027] (1) A nickel component with a nickel content of 5-50%, preferably, a nickel content of 10-45%, more preferably, a nickel content of 13-41%;

[0028] (2) The auxiliary metal component has a metal content of 0.01 to 10%, preferably, the metal content of the auxiliary is 0.1 to 1.5%, more preferably, the metal content of the auxiliary is 0.37 to 1.15%;

[0029] (3) The remaining alumina carrier.

[0030] The nickel component is nickel oxide; the auxiliary metal component is selected from at least one oxide of magnesium, calcium, lanthanum, barium, and cerium.

[0031] The nickel catalyst obtained by the preparation method provided by the present invention is subjected to reduction treatment to partially reduce nickel oxide to active nickel, resulting in a catalyst with high nickel component dispersion and small average nickel particle size. For example, the nickel dispersion is 0.5~5% and the nickel particle size is 10~100nm. Preferably, the nickel dispersion is 1.0~3.5% and the nickel particle size is 20~65nm.

[0032] A third objective of this invention is to provide a rotation-enhanced impregnation apparatus for implementing the above-described method for preparing the nickel catalyst, or for preparing the above-described nickel catalyst.

[0033] According to an embodiment of the present invention, the device includes: a rotary enhanced packed bed, a storage tank, and a liquid pump. The rotary enhanced packed bed has a cylindrical structure, including a liquid distributor, rotary packing, and a carrier ring. The liquid distributor is located at the center of the rotary enhanced packed bed, and the rotary packing and carrier ring are arranged sequentially around the liquid distributor. The carrier ring is a wire mesh carrier ring, and a certain amount of carrier particles are filled inside the carrier ring according to actual needs. A liquid outlet is provided at the lower end of the rotary enhanced packed bed to discharge unimpregnated liquid and return it to the storage tank. The carrier ring rotates at a low speed driven by a motor, while the rotary packing rotates at a high speed driven by a motor. The impregnation liquid is pumped into the impregnation device by the liquid pump and evenly sprayed into the inner side of the rotary packing through the liquid distributor. Under the action of centrifugal force, the mixed salt solution is sheared into tiny liquid micro-elements by the rotary packing, which come into contact with the alumina carrier in the low-speed rotating carrier ring. After a period of enhanced impregnation, a nickel catalyst precursor is obtained.

[0034] The rotating packed bed of this invention is a chemical intensification device that can highly enhance micro-mixing and mass transfer. In a hypergravity environment, the enormous shear force generated by the rotation of the packing material can shear the fluid into extremely small liquid micro-elements, increasing the phase contact area and greatly improving the mixing and mass transfer effects between phases. The mass transfer coefficient is 10-1000 times higher than that of conventional reactors. Therefore, the rotating intensified impregnation method of this invention can improve the dispersion of catalytically active components and enhance catalytic performance.

[0035] This invention utilizes rotational intensification technology, employing a rotating packed bed as the catalyst preparation equipment. Using wire mesh or cylindrical packing, the impregnation solution is formed into a mist and droplets under centrifugal force and sprayed onto the carrier surface at extremely high speeds. The highly dispersed fine droplets, extremely high initial velocity, and constantly renewing phase interface effectively improve the diffusion and permeation rate of the impregnation solution in the carrier pores, promoting the uniform adsorption of active components on the carrier surface and significantly shortening the impregnation time. Finally, after drying and calcination, a nickel catalyst with high nickel component dispersion and small average nickel particle size is prepared.

[0036] Compared with the prior art, the present invention has the following advantages:

[0037] 1. The preparation method provided by the present invention greatly shortens the impregnation time of the metal active component, and the metal active component can be more uniformly adsorbed on the surface of the carrier.

[0038] 2. The nickel catalyst prepared by the method of the present invention has higher dispersion and smaller particle size;

[0039] 3. The preparation method provided by this invention effectively avoids carrier breakage, has a simple process, is easy to implement in industrial production, and has broad application prospects. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of a rotary hardening impregnation device; in the diagram: 1-1 is motor 1, 1-2 is motor 2, 1-3 is rotary hardening packing bed, 1-4 is liquid storage tank, 1-5 is liquid pump, 1-6 is liquid distributor, 1-7 is rotary packing, 1-8 is wire mesh carrier ring, 1-9 is alumina carrier, 1-10 is impregnation liquid inlet, and 1-11 is impregnation liquid outlet.

[0041] Figure 2 This is a side view of the internal structure of the rotary hardening impregnation equipment. In the figure: 2-1 is the wire mesh carrier ring gear, 2-2 is the rotary hardening packing bed, 2-3 is the wire mesh carrier ring, 2-4 is the alumina carrier, 2-5 is the rotary packing, 2-6 is the liquid distributor, and 2-7 is the impregnation liquid outlet. Detailed Implementation

[0042] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0043] The testing instruments and conditions used in this embodiment are as follows:

[0044] The specific surface area (BET) and pore volume of the nickel catalyst were measured by N2 adsorption-desorption method.

[0045] The dispersion of nickel components and the average nickel particle size in the nickel catalyst were measured by hydrogen chemisorption.

[0046] The raw materials used in the examples are from the following sources:

[0047] The molded alumina carrier was produced by Beijing Research Institute of Chemical Industry;

[0048] All other reagents used were commercially available and of analytical grade.

[0049] The rotary impregnation device used in the embodiments is as follows: Figure 1As shown, the system includes: a rotary enhanced packing bed 1-3, a liquid storage tank 1-4, a liquid pump 1-5, a motor 1-1, and a motor 1-2. The rotary enhanced packing bed 1-3 is a cylindrical structure, including a liquid distributor 1-6, rotary packing 1-7, and a wire mesh carrier ring 1-8. The center of the rotary enhanced packing bed 1-3 is the liquid distributor 1-6, which is closed at one end and has a pipe opening at the other end, connecting to the liquid pump 1-5 through a pipe. Rotary packing 1-7 and wire mesh carrier ring 1-8 are arranged in sequence around the liquid distributor 1-6. The lower end of the rotary enhanced packing bed 1-3 is provided with a liquid outlet 1-10 for discharging unimpregnated liquid and returning it to the liquid storage tank 1-4. The wire mesh carrier ring 1-8 is filled with alumina carrier 1-9, and the rotating packing 1-7 is made of stainless steel wire mesh. Motor 1 drives the carrier ring 1-8 to rotate at a low speed, and motor 2 drives the rotating packing 1-7 to rotate at a high speed. The impregnation liquid is pumped into the impregnation device by liquid pump 1-5 and evenly sprayed into the inner side of the rotating packing 1-7 by liquid distributor 1-6. Under the action of centrifugal force, the impregnation liquid is sheared into tiny liquid micro-elements by the rotating packing 1-7 and comes into contact with the alumina carrier 1-9 in the low-speed rotating carrier ring 1-8. After a period of enhanced impregnation, a nickel catalyst precursor is obtained.

[0050] Example 1

[0051] The rotation-strengthened impregnation method was used to impregnate 50g of molded alumina carrier (produced by Beijing Research Institute of Chemical Industry, with a BET specific surface area of ​​143m²). 2 / g, pore volume is 0.74m 3 The catalyst precursor (containing 10 wt% nickel and 0.5 wt% magnesium) was loaded into a wire mesh carrier ring. An impregnation solution containing nickel nitrate and magnesium nitrate (containing 10 wt% nickel and 0.5 wt% magnesium) was placed in a liquid tank. The rotating packed bed was started, with the packing bed rotating at 1000 rpm and the carrier ring rotating at 10 rpm. The impregnation solution was pumped into the rotating bed through a horizontal flow pump. After 30 min of enhanced impregnation, the catalyst precursor was removed and then dried at 120 °C for 2 h and calcined at 600 °C for 4 h. Finally, a nickel catalyst with a nickel content of 13% and a magnesium content of 0.41% was obtained, denoted as A-1.

[0052] Example 2

[0053] The rotation-strengthened impregnation method was used to impregnate 50g of molded alumina carrier (produced by Beijing Research Institute of Chemical Industry, with a BET specific surface area of ​​143m²). 2 / g, pore volume is 0.74m 3The catalyst precursor (containing 15 wt% nickel and 0.5 wt% magnesium) was loaded into a wire mesh carrier ring. An impregnation solution containing nickel nitrate and magnesium nitrate (containing 15 wt% nickel and 0.5 wt% magnesium) was placed in a liquid tank. The rotating packed bed was started, with the packing rotor rotating at 2000 rpm and the wire mesh carrier ring rotating at 10 rpm. The impregnation solution was pumped into the rotating bed through a horizontal flow pump. After 30 minutes of enhanced impregnation, the catalyst precursor was removed and then dried at 120℃ for 2 hours and calcined at 600℃ for 4 hours. Finally, a nickel catalyst with a nickel content of 18% and a magnesium content of 0.39% was obtained, denoted as A-2.

[0054] Example 3

[0055] The rotation-strengthened impregnation method was used to impregnate 50g of molded alumina carrier (produced by Beijing Research Institute of Chemical Industry, with a BET specific surface area of ​​143m²). 2 / g, pore volume is 0.74m 3 The catalyst precursor (containing 15 wt% nickel and 0.5 wt% magnesium) was loaded into a wire mesh carrier ring. An impregnation solution containing nickel nitrate and magnesium nitrate (containing 15 wt% nickel and 0.5 wt% magnesium) was placed in a liquid tank. The rotating packed bed was started, with the packing rotor rotating at 2000 rpm and the wire mesh carrier ring rotating at 10 rpm. The impregnation solution was pumped into the rotating bed using a horizontal pump. After 30 minutes of intensive impregnation, the catalyst precursor was removed and then dried at 120℃ for 4 hours and calcined at 600℃ for 6 hours. The resulting catalyst was subjected to the same steps once more, finally yielding a nickel catalyst with a nickel content of 31% and a magnesium content of 0.40%, designated A-3.

[0056] Example 4

[0057] The rotation-strengthened impregnation method was used to impregnate 50g of molded alumina carrier (produced by Beijing Research Institute of Chemical Industry, with a BET specific surface area of ​​143m²). 2 / g, pore volume is 0.74m 3 The catalyst precursor (containing 15 wt% nickel and 0.5 wt% magnesium) was loaded into a wire mesh carrier ring. An impregnation solution containing nickel nitrate and magnesium nitrate (containing 15 wt% nickel and 0.5 wt% magnesium) was placed in a liquid tank. The rotating packed bed was started, with the packing rotor rotating at 2000 rpm and the wire mesh carrier ring rotating at 10 rpm. The impregnation solution was pumped into the rotating bed using a horizontal pump. After 30 minutes of intensive impregnation, the catalyst precursor was removed and then dried at 120℃ for 4 hours and calcined at 600℃ for 6 hours. The resulting catalyst was subjected to the same steps twice more, finally yielding a nickel catalyst with a nickel content of 39% and a magnesium content of 0.40%, designated A-4.

[0058] Example 5

[0059] The rotation-strengthened impregnation method was used to impregnate 50g of molded alumina carrier (produced by Beijing Research Institute of Chemical Industry, with a BET specific surface area of ​​143m²). 2 / g, pore volume is 0.74m 3The catalyst precursor (containing 15 wt% nickel and 0.5 wt% calcium) was loaded into a wire mesh carrier ring. An impregnation solution containing nickel nitrate and calcium nitrate (containing 15 wt% nickel and 0.5 wt% calcium) was placed in a liquid tank. The rotating packed bed was started, with the packing rotor rotating at 2000 rpm and the wire mesh carrier ring rotating at 10 rpm. The impregnation solution was pumped into the rotating bed using a horizontal pump. After 30 minutes of intensive impregnation, the catalyst precursor was removed and then dried at 120℃ for 4 hours and calcined at 600℃ for 6 hours. The resulting catalyst was subjected to the same steps twice more, finally yielding a nickel catalyst with a nickel content of 39% and a calcium content of 0.37%, designated A-5.

[0060] Example 6

[0061] The rotation-strengthened impregnation method was used to impregnate 50g of molded alumina carrier (produced by Beijing Research Institute of Chemical Industry, with a BET specific surface area of ​​143m²). 2 / g, pore volume is 0.74m 3 The catalyst precursor (containing 15 wt% nickel and 0.5 wt% lanthanum) was loaded into a wire mesh carrier ring. An impregnation solution containing nickel nitrate and lanthanum nitrate (containing 15 wt% nickel and 0.5 wt% lanthanum) was placed in a liquid tank. The rotating packed bed was started, with the packing rotor rotating at 2000 rpm and the wire mesh carrier ring rotating at 10 rpm. The impregnation solution was pumped into the rotating bed using a horizontal pump. After 30 minutes of intensive impregnation, the catalyst precursor was removed and then dried at 120℃ for 4 hours and calcined at 600℃ for 6 hours. The resulting catalyst was subjected to the same steps twice more, finally yielding a nickel catalyst with a nickel content of 39% and a lanthanum content of 1.14%, designated A-6.

[0062] Example 7

[0063] The rotation-strengthened impregnation method was used to impregnate 50g of molded alumina carrier (produced by Beijing Research Institute of Chemical Industry, with a BET specific surface area of ​​143m²). 2 / g, pore volume is 0.74m 3 The catalyst precursor (containing 15 wt% nickel and 0.5 wt% cerium) was loaded into a wire mesh carrier ring. An impregnation solution containing nickel nitrate and cerium nitrate (containing 15 wt% nickel and 0.5 wt% cerium) was placed in a liquid tank. The rotating packed bed was started, with the packing rotor rotating at 2000 rpm and the wire mesh carrier ring rotating at 10 rpm. The impregnation solution was pumped into the rotating bed using a horizontal pump. After 30 minutes of intensive impregnation, the catalyst precursor was removed and then dried at 120℃ for 4 hours and calcined at 600℃ for 6 hours. The resulting catalyst was subjected to the same steps twice more, finally yielding a nickel catalyst with a nickel content of 39% and a cerium content of 1.15%, designated A-7.

[0064] Example 8

[0065] The rotation-strengthened impregnation method was used to impregnate 50g of molded alumina carrier (produced by Beijing Research Institute of Chemical Industry, with a BET specific surface area of ​​193m²). 2 / g, pore volume is 0.94m 3The catalyst precursor (containing 15 wt% nickel and 0.5 wt% lanthanum) was loaded into a wire mesh carrier ring. An impregnation solution containing nickel nitrate and lanthanum nitrate (containing 15 wt% nickel and 0.5 wt% lanthanum) was placed in a liquid tank. The rotating packed bed was started, with the packing rotor rotating at 2000 rpm and the wire mesh carrier ring rotating at 10 rpm. The impregnation solution was pumped into the rotating bed using a horizontal pump. After 30 minutes of intensive impregnation, the catalyst precursor was removed and then dried at 120℃ for 4 hours and calcined at 600℃ for 6 hours. The resulting catalyst was subjected to the same steps twice more to obtain a nickel catalyst with a nickel content of 40% and a lanthanum content of 1.14%, designated A-8.

[0066] Example 9

[0067] The rotation-strengthened impregnation method was used to impregnate 50g of molded alumina carrier (produced by Beijing Research Institute of Chemical Industry, with a BET specific surface area of ​​231m²). 2 / g, pore volume 1.20m 3 The catalyst precursor (containing 15 wt% nickel and 0.5 wt% lanthanum) was loaded into a wire mesh carrier ring. An impregnation solution containing nickel nitrate and lanthanum nitrate (containing 15 wt% nickel and 0.5 wt% lanthanum) was placed in a liquid tank. The rotating packed bed was started, with the packing rotor rotating at 2000 rpm and the wire mesh carrier ring rotating at 10 rpm. The impregnation solution was pumped into the rotating bed using a horizontal pump. After 30 minutes of intensive impregnation, the catalyst precursor was removed and then dried at 120℃ for 4 hours and calcined at 600℃ for 6 hours. The resulting catalyst was subjected to the same steps twice more to obtain a nickel catalyst with a nickel content of 41% and a lanthanum content of 1.15%, designated A-9.

[0068] Comparative Example 1

[0069] Using the traditional equal-volume impregnation method, 50g of molded alumina carrier (produced by Beijing Chemical Research Institute, with a BET specific surface area of ​​143m²) was impregnated. 2 / g, pore volume is 0.74m 3 The catalyst (D-1) is impregnated with a nickel nitrate / magnesium nitrate impregnation solution containing 10wt% nickel and 0.5wt% magnesium, and then dried at 100℃ for 10h and calcined at 400℃ for 10h to obtain a nickel catalyst with a nickel content of 13% and a magnesium content of 0.40%.

[0070] Comparative Example 2

[0071] Using the traditional equal-volume impregnation method, 50g of molded alumina carrier (produced by Beijing Chemical Research Institute, with a BET specific surface area of ​​143m²) was impregnated. 2 / g, pore volume is 0.74m 3 The catalyst (D-2) was impregnated with a nickel nitrate / magnesium nitrate impregnation solution containing 15wt% nickel and 0.5wt% magnesium, and then dried at 100℃ for 10h and calcined at 400℃ for 10h to obtain a nickel catalyst with a nickel content of 19% and a magnesium content of 0.39%.

[0072] Comparative Example 3

[0073] Using the traditional equal-volume impregnation method, 50g of molded alumina carrier (produced by Beijing Chemical Research Institute, with a BET specific surface area of ​​143m²) was impregnated. 2 / g, pore volume is 0.74m 3 The catalyst (D-3) was impregnated with a nickel nitrate / magnesium nitrate impregnation solution containing 15wt% nickel and 0.5wt% magnesium, followed by drying at 100℃ for 10h and calcining at 400℃ for 10h. After repeating the impregnation, drying and calcination steps twice, a nickel catalyst with a nickel content of 39% and a magnesium content of 0.40% was finally obtained.

[0074] Comparative Example 4

[0075] The rotation-strengthened impregnation method was used to impregnate 50g of molded alumina carrier (produced by Beijing Research Institute of Chemical Industry, with a BET specific surface area of ​​143m²). 2 / g, pore volume is 0.74m 3 Using nickel nitrate and lanthanum nitrate as packing material, an impregnation solution containing 15 wt% nickel and 0.5 wt% magnesium was placed in a liquid tank. A rotating packed bed was started, with the packing rotor rotating at 2000 rpm. The impregnation solution was pumped into the rotating bed using a horizontal flow pump. After 30 minutes of intensive impregnation, the catalyst precursor was removed and then dried at 120°C for 4 hours and calcined at 600°C for 6 hours. The resulting catalyst was subjected to the same steps twice more, finally yielding a nickel catalyst with a nickel content of 39% and a magnesium content of 0.40%, denoted as D-4.

[0076] Test Example 1

[0077] The samples A1-10 and D1-4 were characterized by chemical pulse adsorption of hydrogen. The specific method was as follows: the samples were reduced in a hydrogen atmosphere at 450℃ for 4 hours, purged with argon at 450℃ for 2 hours, and then cooled to 45℃. At this temperature, pulse adsorption was performed with a 10% hydrogen-argon mixture. Finally, the nickel dispersion and nickel particle size of the catalyst were obtained. The results are shown in Table 1.

[0078] Table 1

[0079]

[0080] Compared to the nickel-based catalysts in Comparative Examples 1-3 prepared by the traditional equal-volume impregnation method, the nickel catalysts obtained by the rotation-enhanced impregnation method in Examples 1-9 exhibit higher nickel dispersion and smaller nickel particle size. This is because the alumina support is loosely packed in the wire mesh support ring, and the rotation of the wire mesh support ring can drive the slow displacement of the support, allowing the impregnation liquid, which forms a mist or droplets under centrifugal force, to be uniformly sprayed onto the support surface at extremely high speed. In addition, the slow rotation of the support in the wire mesh support ring does not subject it to large compression, effectively preventing the support from breaking.

Claims

1. A method for preparing a nickel catalyst, comprising: A rotary impregnation device is used to impregnate a solution containing nickel salt and auxiliary metal salt as the impregnation liquid. The alumina support is placed in a rotatable wire mesh support ring. Under the action of centrifugal force, the impregnation liquid is sprayed onto the rotating alumina support. After drying and calcination, the nickel catalyst is obtained. The preparation method specifically includes the following steps: Step 1: Load the alumina carrier into the wire mesh carrier ring, pump the mixed salt solution containing nickel salt and auxiliary metal salt into the rotary strengthening impregnation device, and spray it evenly into the inside of the rotary packing through the liquid distributor. Step 2: Under the action of centrifugal force, the mixed salt solution is sheared into tiny liquid micro-elements by the rotating packing material, which come into contact with the alumina carrier in the low-speed rotating wire mesh carrier ring, thereby enhancing the impregnation and obtaining the nickel catalyst precursor. Step 3: Dry and calcine the nickel catalyst precursor obtained in Step 2 to obtain the nickel catalyst.

2. The preparation method according to claim 1, characterized in that, The nickel salt is selected from at least one of nickel nitrate, nickel sulfate, and basic nickel carbonate; and / or, The auxiliary metal salt is selected from at least one of the metal salts of magnesium, calcium, lanthanum, barium, and cerium.

3. The preparation method according to claim 1, characterized in that, The auxiliary metal salt is selected from at least one of the nitrates, sulfates or carbonates of magnesium, calcium, lanthanum, barium or cerium.

4. The preparation method according to claim 1, characterized in that, In step one: In the mixed salt solution, the mass percentage concentration of metallic nickel is 1-15%; and / or, In the mixed salt solution, the mass percentage concentration of the auxiliary metal is 0.01~5%; and / or, The rotating packing material is either a wire mesh or a cylindrical packing material.

5. The preparation method according to claim 4, characterized in that, In step one: In the mixed salt solution, the mass percentage concentration of metallic nickel is 5-15%; and / or, In the mixed salt solution, the mass percentage concentration of the auxiliary metal is 0.1% to 1%.

6. The preparation method according to claim 1, characterized in that, In step two: The rotational speed of the rotating packing is 1000~2000 rpm; and / or, The rotational speed of the wire mesh carrier ring is 10~20 rpm; and / or, The time for the enhanced impregnation is 10-30 minutes.

7. The preparation method according to claim 1, characterized in that, In step three: The drying conditions are 100~120℃ for 2~10 hours; and / or, The calcination conditions are 400~600℃ for 2~10 hours.

8. A nickel catalyst prepared by the preparation method according to any one of claims 1 to 7.

9. The nickel catalyst according to claim 8, characterized in that, The nickel catalyst comprises the following components, based on a total weight of 100%: (1) Nickel components with a nickel content of 5-50%; (2) The metal content of the additive is 0.01~10%; (3) The remaining alumina carrier.

10. The nickel catalyst according to claim 9, characterized in that, Nickel content is 10-45%; The metal content of the additives is 0.1~1.5%.

11. The nickel catalyst according to claim 9, characterized in that, The nickel component is nickel oxide; and / or, The auxiliary metal component is selected from at least one of the oxides of magnesium, calcium, lanthanum, barium, and cerium.

12. A rotary impregnation apparatus for carrying out the preparation method according to any one of claims 1 to 7, or for preparing the nickel catalyst according to any one of claims 8 to 11; the apparatus comprising: The rotating reinforced packing bed, the liquid storage tank, and the liquid pump are described. The rotating reinforced packing bed is a cylindrical structure, including a liquid distributor, rotating packing, and wire mesh carrier rings. The liquid distributor is located at the center of the rotating reinforced packing bed, and the rotating packing and wire mesh carrier rings are arranged in sequence around the liquid distributor. A liquid outlet is provided at the lower end of the rotating reinforced packing bed to discharge the unimpregnated liquid and return it to the liquid storage tank.

13. The apparatus according to claim 12, characterized in that, The rotating packing material is either a wire mesh or a cylindrical packing material.

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