Shell type supported Ni-based catalyst as well as preparation method and application thereof

Abstract

The invention discloses a shell type supported Ni-based catalyst as well as a preparation method and application thereof, and relates to the technical field of catalysts. The method comprises the following steps: improving a vacuum drum impregnator, and heating and stirring nickel salt, a surfactant, deionized water and a peptizing aid to obtain impregnation liquid; pumping the impregnation liquid into a spraying disc of a vacuum drum impregnator, placing the catalyst carrier in the vacuum drum impregnator, and performing spraying impregnation to obtain a primary impregnation catalyst precursor; drying, aging and roasting the primary impregnation catalyst precursor to obtain a primary impregnation catalyst; and repeatedly spraying, drying, aging and roasting for a plurality of times after dipping the catalyst for one time to obtain the shell-type supported Ni-based catalyst. The shell-type supported Ni-based catalyst is used for hydrogenation reaction of 3-hydroxypropionaldehyde, and under the same reaction efficiency, the loading equivalent of the catalyst is lower, that is, the catalyst has higher mass space velocity, mild reaction conditions, higher raw material conversion rate and higher product selectivity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of catalysts, in particular to a shell-type supported Ni-based catalyst and a preparation method and application thereof. BACKGROUND

[0002] 1,3-propanediol (1,3-PDO) is a colorless, odorless viscous liquid, which is soluble in water, alcohol, ether and other solvents. 1,3-PDO is an important chemical raw material, which is widely used in polyester, polyurethane, cosmetics, degradable plastics, pharmaceutical intermediates, inks, printing and dyeing, lubricants and other fields, but its most important use is as a polymer monomer, replacing ethylene glycol and butanediol to produce polyol polyester, which is used to manufacture new polyester fiber PTT with excellent performance, and then applied to clothing, carpet, electronics, automobile and other markets. In recent years, 1,3-PDO has developed rapidly, mainly driven by the reverse of the downstream PTT consumer market.

[0003] With the development of domestic PTT and the continuous maturity of the downstream market, the cost of 1,3-PDO largely determines the market competitiveness of PTT. Optimizing and improving the production technology of 1,3-PDO is the only way to reduce the production cost of PTT and accelerate the development of PTT in the future market. Therefore, the development of low-cost 1,3-PDO products has become a research and development hotspot for scientific research institutions and enterprises.

[0004] The synthesis technology of 1,3-PDO mainly includes biological method, propylene method and ethylene oxide method. The production cost of 1,3-PDO synthesized by biological method is high in China, and the propylene method and ethylene oxide method have not been industrialized in China. Among them, the propylene method process is to oxidize propylene to propylene aldehyde, and then 3-hydroxypropionaldehyde (3-HPA) is obtained by hydration, and then two-stage hydrogenation is used to obtain 1,3-PDO. The propylene method process has the advantages of simple process, clear catalyst system and low requirement on equipment.

[0005] 3-hydroxypropanal hydrogenation to 1,3-PDO, the catalyst used is generally noble metal Pd, Pt and non-noble metal Ni system, because the cost of noble metal is high and difficult to obtain, the market gradually uses improved activity Ni catalyst to replace noble metal catalyst. Shell Company of the United States uses Ni / SiO2 / Al2O3 catalyst containing 50wt.% Ni, under the conditions of reaction pressure 5-7 MPa, temperature 50-80℃, 3-hydroxypropanal 3-22.6wt.% to hydrogenate to prepare 1,3-PDO. Raney nickel containing molybdenum is used as catalyst by Hüls AG of Germany, under the conditions of reaction pressure 1.5-5.5 MPa, temperature 40-90℃, 3-hydroxypropanal 20wt.% to hydrogenate to prepare 1,3-PDO. Porous high nickel catalyst is used by Lanzhou Chemical Research Institute of China Petroleum, under the conditions of reaction pressure 5 MPa, temperature 40-100℃, 3-hydroxypropanal 5-15wt.% to hydrogenate to prepare 1,3-PDO. Raney nickel is used as catalyst by Shanghai Petrochemical Co., Ltd., under the conditions of reaction pressure 6 MPa, temperature 50-130℃, 3-hydroxypropanal 5-25wt.% to hydrogenate to prepare 1,3-PDO. The mass space velocity of the above catalyst is 1-3h -1 , the conversion rate of 3-hydroxypropanal is 96-100%, and the selectivity of 1,3-PDO is 95-98.5%. When the mass space velocity exceeds 3h -1 , the performance of the catalyst decreases, the active components of the catalyst are lost and covered, the pressure of product rectification separation module increases, and technical limitations are brought to pilot scale-up and industrialization design. SUMMARY

[0006] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art, provide a shell-type supported Ni-based catalyst, a preparation method and application thereof, and the prepared shell-type supported Ni-based catalyst has stable physical and chemical properties, is used for 3-hydroxypropanal hydrogenation reaction, has lower catalyst loading equivalent under the same reaction efficiency, that is, the catalyst has higher mass space velocity, mild reaction conditions, higher raw material conversion rate and higher product selectivity.

[0007] The technical scheme of the present application is as follows: In a first aspect, the present application provides a preparation method of a shell-type supported Ni-based catalyst, comprising the following steps: S1: heating and stirring nickel salt, surfactant, deionized water and peptizing aid uniformly to obtain an impregnation solution; the surfactant is sodium lauryl polyether sulfate (SLES), sodium fatty alcohol polyoxyethylene ether sulfate (AES) or Tween 80; the peptizing aid is two of cetyltrimethylammonium bromide (CTAB), tetrabutylammonium bromide (TBAB), sodium alpha-alkenyl sulfonate (AOS), polyethylene glycol (PEG), carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVA); S2: pumping the impregnation solution into the vacuum drum impregnator, and placing the catalyst carrier in the vacuum drum impregnator, and spraying impregnation to obtain a first impregnated catalyst precursor; the mass ratio of the impregnation solution to the catalyst carrier is (0.5-1):1; the catalyst carrier is a molecular sieve catalyst carrier made of one or two of silicon, aluminum and carbon; The vacuum drum impregnator comprises a drum provided with a feeding port, the drum is connected with a rotating shaft of a motor one and connected with a vacuum pump, and the drum is provided with electric heating wires; a spraying disc is arranged in the drum, the spraying disc is connected with a liquid inlet pipe, the liquid inlet pipe is mounted on the drum through a bearing, and the liquid inlet pipe is connected with a rotating shaft of a motor two; the catalyst carrier is placed in the drum, the impregnation solution is sprayed on the surface of the catalyst carrier through the spraying disc; a turbine is arranged in the spraying disc, the spraying disc is provided with spraying needle tubes from the center to the outer edge direction and the spraying needle tubes are outwardly inclined; the rotating direction of the drum is opposite to that of the spraying disc, and the rotating speed of the spraying disc is 115000-30000 r / min; S3: drying, aging and calcining the first impregnated catalyst precursor to obtain a first impregnated catalyst; S4: repeatedly performing the spraying, drying, aging and calcining operations on the first impregnated catalyst for several times to obtain a shell-type supported Ni-based catalyst.

[0008] The existing spraying disc is of a shower type, and the disc surface is provided with spraying holes. In the process that the impregnation solution reaches the spraying holes and is thrown out by centrifugal force, the controllability of the centrifugal force is poor, the diameters of the spraying droplets are uneven, the impregnation depths of the impregnation solution into the catalyst carrier are different, the distribution of the active components on the surface of the catalyst carrier cannot present a uniform layer, and after multiple impregnations, the requirement of shell-type layer distribution cannot be met. In the present application, the rotating speed of the spraying disc cooperates with the turbocharging to ensure that the impregnation solution is uniformly thrown out in the spraying impregnation process to form spraying droplets, and the diameters of the spraying droplets are controllable. On the one hand, the impregnation solution is uniformly present in the drum in the form of thin mist droplets, the catalyst carrier flows uniformly in the drum, the impregnation solution is impregnated on the surface of the catalyst carrier, and is quickly absorbed and dispersed into the pore structure of the catalyst carrier to form a controllable layer-type impregnation interface on the outer surface of the catalyst carrier; on the other hand, the catalyst carrier has a pore structure with a gradient pore size distribution, and the uniform mist droplets can slow down the capillary action on the surface and inside of the catalyst carrier, the impregnation depth and the layer-type impregnation interface are more controllable, and lay a foundation for forming a shell-type layer structure through multiple impregnations. In addition, the spraying disc surface is provided with outwardly inclined spraying needle tubes, and the rotating direction of the drum is opposite to that of the spraying disc. The mist droplets in the space inside the drum are mixed and impregnated with the catalyst carrier in a cyclone manner, and the multi-layer effect is complementary, thereby improving the impregnation efficiency and ideal impregnation effect. The preparation method of the present application can make the active components form a uniformly distributed shell-type layer structure on the surface of the catalyst carrier, effectively prevent the agglomeration and clumping of the active components after the post-treatment is completed, and improve the efficiency of mass and heat transfer in the catalytic process and the catalytic stability.

[0009] Preferably, in step S1, the nickel salt is nickel nitrate, nickel sulfamate or nickel acetylacetonate.

[0010] Preferably, in step S1, the concentration of the nickel salt in the impregnation solution is 0.01-2 mol / L.

[0011] Preferably, in step S1, the concentration of the surfactant in the impregnation solution is 0.6-1 wt.%.

[0012] Preferably, in step S1, the mass of the peptizing agent is 0.15-0.7% of the mass of the catalyst carrier.

[0013] Preferably, in step S2, when the spray impregnation is performed, the diameter of the spray droplets is 100-800 μm; the rotating speed of the drum is 150-200 r / min; the temperature is 60-90℃; and the vacuum degree is -0.25-0.2 MPa.

[0014] Preferably, in steps S3 and S4, the drying temperature is 80-150℃, the drying time is 1-24 h, the aging temperature is 100-300℃, the aging time is 1-48 h, the calcination temperature is 350-850℃, and the calcination time is 1-12 h; and in step S4, the Ni content of the obtained shell-type supported Ni-based catalyst is 1.5-5 wt.%.

[0015] In a second aspect, the present application provides a shell-type supported Ni-based catalyst prepared by the above-mentioned method for preparing a shell-type supported Ni-based catalyst.

[0016] In a third aspect, the present application provides an application of the above-mentioned shell-type supported Ni-based catalyst, wherein the shell-type supported Ni-based catalyst is used in a 3-hydroxypropanal hydrogenation reaction, the reaction pressure is 2-8 MPa, the reaction temperature is 30-100℃, the mass space velocity is 1-5 h-1, and the hydrogenation reaction is carried out under the catalysis of the shell-type supported Ni-based catalyst. -1 .

[0017] Compared with the prior art, the present application has the following beneficial effects: 1. The preparation method of the shell-type supported Ni-based catalyst of the present application, by optimizing the addition amount of the impregnation liquid formula, surfactant and peptizing agent, the mist droplets are uniformly dispersed in the impregnation spraying process, the diameter distribution is concentrated, the surface tension and penetration speed are uniform after contacting with the surface of the catalyst carrier, effectively preventing the agglomeration and clumping of the active component after the end of the post-treatment. By a specific mass ratio of the impregnation liquid and the catalyst carrier, the wear and breakage of the catalyst carrier during the rotation of the vacuum drum impregnator can be significantly reduced, and the good flowability of the catalyst carrier can also effectively ensure the uniformity of the macroscopic dispersion of the active component on the surface of the catalyst carrier and the depth of the impregnation into the surface of the catalyst carrier during the impregnation loading process. At the same time, the present application uses the vacuum drum impregnation process and multiple impregnation means, by adjusting the spraying parameters, the temperature, pressure and rotation speed of the drum inside the vacuum drum impregnator and other process nodes, so that the impregnation liquid spraying speed is uniform, the uniform suspended mist droplets are quickly formed, the layered gradient distribution limit of the active component is obvious, and the impregnation process is more uniform and controllable. The shell-type supported Ni-based catalyst prepared by the present application has stable physical and chemical properties, and is used for 3-hydroxypropanal hydrogenation reaction, under the same reaction efficiency, the catalyst loading equivalent is lower, i.e. the catalyst has higher mass space velocity, mild reaction conditions, higher raw material conversion rate and higher product selectivity.

[0018] 2. The preparation method of the shell-type supported Ni-based catalyst of the present application, the raw materials, impregnation equipment and operation process are simple, easy to obtain and controllable, which provides conditions for realizing batch industrial production, and has good industrialization and market prospects. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is the structural schematic diagram of the vacuum drum impregnator of the present application.

[0020] Figure 2 is the SEM graph of the shell-type supported Ni-based catalyst prepared in Example 1 of the present application.

[0021] In the figure, 1, drum; 101, feed inlet; 102, inner lining; 2, spraying disc; 201, spraying needle tube; 3, motor one; 4, liquid inlet pipe; 5, motor two. DETAILED DESCRIPTION

[0022] In order to enable the personnel in the technical field to better understand the technical solutions in the present application, the technical solutions of the present application will be clearly and completely described below in combination with the embodiments of the present application.

[0023] Example 1 As Figure 1As shown, the vacuum drum impregnator of the embodiment includes a drum 1, the inner lining 102 of which is oval, the drum 1 is provided with a feeding port 101, the drum 1 is connected with the rotating shaft of motor one 3 and the drum 1 is connected with a vacuum pump, the drum 1 is provided with electric heating wires; the drum 1 is provided with a spraying disc 2, the spraying disc 2 is connected with a liquid inlet pipe 4, the liquid inlet pipe 4 is mounted on the drum 1 through a bearing, the liquid inlet pipe 4 is connected with the rotating shaft of motor two 5; the catalyst carrier is placed in the drum 1, the impregnating solution is sprayed on the surface of the catalyst carrier through the spraying disc 2; the spraying disc 2 is provided with a turbine, the spraying disc 2 is provided with spraying needle tubes 201 from the center to the outer edge direction and the spraying needle tubes 201 are inclined outward.

[0024] Working principle: The catalyst carrier is put into the drum 1 from the feeding port 101 of the drum 1, the impregnating solution is pumped into the spraying disc 2 through the liquid inlet pipe 4 and finally sprayed on the surface of the catalyst carrier through the spraying needle tubes 201; at the same time, the vacuum pump pumps the drum 1. The turbine in the spraying disc 2 can make the impregnating solution evenly centrifuged to form spraying droplets in the spraying and impregnating process, on the one hand, the catalyst carrier flows uniformly in the drum 1, so that the impregnating solution is impregnated on the surface of the catalyst carrier, quickly absorbed and dispersed into the pore structure of the catalyst carrier, and a controllable layered impregnation interface is formed on the outer surface of the catalyst carrier; on the other hand, the catalyst carrier has a pore structure with a gradient pore size distribution, and the uniform size of the droplets can slow down the capillary action of the surface and the inside of the catalyst carrier, the impregnation depth and the layered impregnation interface are more controllable, which lays a foundation for the formation of shell-type layered structure by multiple impregnation. In addition, the spraying needle tubes 201 on the surface of the spraying disc 2 are inclined outward, and under the drive of the motor one 3 and the motor two 5, the rotating direction of the drum 1 and the spraying disc 2 is opposite, the droplets in the space inside the drum 1 are mixed with the catalyst carrier in a cyclone, the multi-layer effect is complementary, and the impregnation efficiency and ideal impregnation effect are improved.

[0025] Embodiment 2 The preparation method of the shell-type supported Ni-based catalyst of the embodiment includes the following steps: S1: prepare a 0.01 mol / L nickel nitrate solution with deionized water, then add a surfactant SLES, a peptizing agent TBAB and PVA so that the concentrations are 0.8 wt.%, 0.1 wt.% and 0.1 wt.% respectively, and stir uniformly at 80℃ to obtain a uniform and slightly turbid green solution without lumps and particles, which is the impregnating solution.

[0026] S2: The impregnation solution was pumped into the liquid inlet pipe 4 of the vacuum drum impregnator of Example 1, and the spherical alumina molecular sieve catalyst carrier JT-202406S (Tianjin Nanhua Catalyst Co., Ltd.) was placed in the drum 1, and the mass ratio of the impregnation solution to the spherical alumina molecular sieve catalyst carrier JT-202406S was 0.75:1. The rotation speed of the drum 1 was adjusted to 200 r / min, the rotation speed of the spraying disc 2 was 15000 r / min, the temperature was 60℃, the vacuum degree was-0.25 MPa, and the spraying impregnation was started to obtain a first impregnated catalyst precursor. During the spraying impregnation, the spraying droplet diameter was 100 μm.

[0027] S3: The first impregnated catalyst precursor was dried at 150℃ for 1 h, aged at 300℃ for 1 h, and calcined at 850℃ for 1 h in sequence to obtain a first impregnated catalyst.

[0028] S4: The first impregnated catalyst was repeatedly subjected to the above spraying, drying, aging and calcining operations for three times to obtain a shell-type supported Ni-based catalyst with a Ni content of 2.5 wt.%, and the physical property detection results are shown in Table 1, the SEM image is shown in Figure 2 , and Figure 2 It can be seen that it is a layered structure.

[0029] Hydrogenation reaction evaluation of the shell-type supported Ni-based catalyst: The shell-type supported Ni-based catalyst was applied to high-pressure fixed-bed hydrogenation reaction, the concentration of 3-hydroxypropanal solution was 15 wt.%, the reaction pressure was 3 MPa, the reaction temperature was 50℃, the mass space velocity was 4 h -1 , the conversion rate of 3-hydroxypropanal was 100%, and the selectivity of 1,3-PDO was 99.7%.

[0030] Example 3 The preparation method of the shell-type supported Ni-based catalyst of the present embodiment comprises the following steps: S1: A 1 mol / L nickel sulfamate solution was prepared with deionized water, and then a surfactant AES, a peptizing agent CTAB, and a CMC were added to make their concentrations 1 wt.%, 0.2 wt.%, and 0.15 wt.% in sequence, and the mixture was stirred uniformly at 80℃ to obtain a uniform light green turbid solution without lumps and particles, which was the impregnation solution.

[0031] S2: The impregnation solution was pumped into the liquid inlet pipe 4 of the vacuum drum impregnator of Example 1, and the spherical carbon-silicon molecular sieve catalyst carrier PRC-101A (Xi'an Kailixin Material Co., Ltd.) was placed in the drum 1, and the mass ratio of the impregnation solution to the spherical carbon-silicon molecular sieve catalyst carrier PRC-101A was 1:1. The rotation speed of the drum 1 was adjusted to 150 r / min, the rotation speed of the spraying disc 2 was 30000 r / min, the temperature was 90°C, the vacuum degree was 0.2 MPa, and the spraying impregnation was started to obtain a primary impregnated catalyst precursor. During the spraying impregnation, the spraying droplet diameter was 800 μm.

[0032] S3: The primary impregnated catalyst precursor was dried at 80°C for 24 h, aged at 100°C for 48 h, and calcined at 350°C for 12 h in sequence to obtain a primary impregnated catalyst.

[0033] S4: The primary impregnated catalyst was repeatedly subjected to the above spraying, drying, aging and calcining operations for three times to obtain a shell-type supported Ni-based catalyst with a Ni content of 1.5 wt.%, and the physical property detection results are shown in Table 1.

[0034] Hydrogenation reaction evaluation of the shell-type supported Ni-based catalyst: The shell-type supported Ni-based catalyst was applied to high-pressure fixed-bed hydrogenation reaction, the concentration of 3-hydroxypropanal solution was 15 wt.%, the reaction pressure was 8 MPa, the reaction temperature was 100°C, the mass space velocity was 5 h-1, and the hydrogenation reaction was carried out for 8 h. -1 The conversion rate of 3-hydroxypropanal was 100%, and the selectivity of 1,3-PDO was 99.5%.

[0035] Example 4 The preparation method of the shell-type supported Ni-based catalyst of the present example comprises the following steps: S1: A 2 mol / L nickel acetylacetonate solution was prepared with deionized water, and then a surfactant Tween 80, a peptizing agent AOS, and PEG were added to make their concentrations 0.6 wt.%, 0.5 wt.% and 0.2 wt.% in sequence, and stirred uniformly at 80°C to obtain a uniform light green turbid solution without lumps and particles, which was the impregnation solution.

[0036] S2: The impregnation solution was pumped into the liquid inlet pipe 4 of the vacuum drum impregnator of Example 1, and the spherical carbon-silicon molecular sieve catalyst carrier PRC-101A (Xi'an Kailixin Material Co., Ltd.) was placed in the drum 1, and the mass ratio of the impregnation solution to the spherical carbon-silicon molecular sieve catalyst carrier PRC-101A was 1:1. The rotation speed of the drum 1 was adjusted to 150 r / min, the rotation speed of the spraying disc 2 was 30000 r / min, the temperature was 90°C, the vacuum degree was 0.2 MPa, and the spraying impregnation was started to obtain a primary impregnated catalyst precursor. During the spraying impregnation, the spraying droplet diameter was 800 μm.

[0037] S3: The once impregnated catalyst precursor was dried at 100°C for 10 h, aged at 160°C for 16 h, and calcined at 650°C for 6 h to obtain the once impregnated catalyst.

[0038] S4: The once impregnated catalyst was subjected to the above spraying, drying, aging, and calcining operations for three more times to obtain a shell-type supported Ni-based catalyst with a Ni content of 5 wt.%, and the physical property test results of which are shown in Table 1.

[0039] Hydrogenation reaction evaluation of the shell-type supported Ni-based catalyst: The shell-type supported Ni-based catalyst was applied to a high-pressure fixed-bed hydrogenation reaction, the concentration of 3-hydroxypropanal solution was 15 wt.%, the reaction pressure was 2 MPa, the reaction temperature was 30°C, the mass space velocity was 1 h -1 , the conversion rate of 3-hydroxypropanal was 100%, and the selectivity of 1,3-PDO was 99.7%.

[0040] Comparative Example 1 The difference from Example 2 is that the alumina pellet carrier ZZ-Al2O3 is used instead of the spherical alumina molecular sieve catalyst carrier JT-202406S of Example 2. The preparation method of the alumina pellet carrier ZZ-Al2O3 is as follows: (1) Preparation of alumina suspension: 12 wt.% pseudoboehmite powder prepared by hydrolysis of aluminum isopropoxide, 8 wt.% peptizing aid PEG, deionized water, and 3 wt.% alumina powder are prepared into a suspension system with a total alumina solid content of 15 wt.%. After being heated to 80°C and stirred uniformly, 0.055 mol / L nitric acid solution is added dropwise to pH=4.5, and the alumina suspension is obtained by stirring.

[0041] (2) Hot oil column forming: The oil phase of the hot oil column is aromatic oil, the oil column temperature is 130°C, and the oil phase thickness is 120 cm. A 30 wt.% hexamethylenetetramine (HMT) solution is prepared, 12 wt.% functional additive urea is added, and the whole system is stirred uniformly. After that, the alumina suspension is added to the alumina slurry, and then dropped into the hot oil column to form a ball, and the temperature is kept for 12 h. The sample is taken out, placed in an 8 wt.% ammonia solution at 1.5 MPa and 120°C for 4 h, washed with water, and finally dried at 100°C for 24 h and calcined at 55°C for 3 h to obtain the alumina pellet carrier ZZ-Al2O3.

[0042] The physical property detection results of the catalyst prepared in the final comparative example 1 are shown in Table 1. As can be seen from Table 1, the specific surface area, pore volume, pore size and particle size of the catalyst obtained in comparative example 1 are similar to those of example 2, but due to the lack of necessary forming conditions and modification process in the preparation process, the mechanical strength of the alumina pellet carrier ZZ-Al2O3 obtained is much lower than that of the spherical alumina molecular sieve catalyst carrier JT-202406S of example 2. Through analysis and detection, the average strength of the catalyst of comparative example 1 is lower than 30N. Since the catalyst activity evaluation method is a fixed bed reaction device, poor mechanical strength of the carrier will cause large wear during catalyst preparation.

[0043] The catalyst obtained in comparative example 1 was applied to high-pressure fixed-bed hydrogenation reaction, the concentration of 3-hydroxypropanal solution was 15wt.%, the reaction pressure was 3MPa, the reaction temperature was 50℃, and the mass space velocity was 4h -1 . Due to the too low strength of the alumina pellet carrier ZZ-Al2O3 of comparative example 1, the wear during impregnation was >5%, the uniformity of the active components on the surface of the catalyst was affected, but the catalytic performance of the catalyst did not show significant difference, the conversion rate of 3-hydroxypropanal was 99.8%, and the selectivity of 1,3-PDO was 99.2%.

[0044] Comparative example 2 The difference from example 3 is that the Ni content is 1.5wt.%, and the spray, drying, aging and calcination operations are completed at one time in step S3 to obtain a shell-type supported Ni-based catalyst.

[0045] The physical property detection results of the catalyst prepared in the final comparative example 2 are shown in Table 1. As can be seen from the detection results, compared with example 3, the specific surface area and pore volume of the catalyst of comparative example 2 decrease significantly, and the average pore size increases to a certain extent. The main reason is that the high-concentration Ni salt rapidly and massively infiltrates into the microporous organization of the catalyst carrier, and the oxides of the active components are blocked in the micropores after subsequent drying and calcination, directly leading to the decrease of specific surface area and pore volume, and the disappearance of micropores also indirectly causes the increase of the average pore size of the overall catalyst. The strength of the catalyst is the inherent property of the carrier, and is not significantly affected by the change of the impregnation method.

[0046] The catalyst obtained in comparative example 2 was applied to high-pressure fixed-bed hydrogenation reaction, the concentration of 3-hydroxypropanal solution was 15wt.%, the reaction pressure was 3MPa, the reaction temperature was 50℃, and the mass space velocity was 4h -1 .

[0047] As can be seen from Table 1, in Example 3, the active component can slowly infiltrate into the micropores of the catalyst carrier by multiple impregnation, and the oxides of the active component after subsequent drying and calcination will not block the micropores. In Comparative Example 2, the active component infiltrates quickly by one-time impregnation, and the micropores of the entire catalyst carrier are full of high-concentration active components. After subsequent drying and calcination, the oxides of the active component will seriously block the micropores, resulting in a decrease in the overall specific surface area and pore volume of the catalyst of Comparative Example 2; and due to the blocking of the micropores, the macropore is not seriously affected, thus slightly increasing the pore diameter of the catalyst. Ultimately, the catalytic performance of the catalyst is seriously affected, resulting in a decrease in the conversion of 3-hydroxypropanal to 90.2%, and the selectivity of 1,3-PDO remains 99.5%.

[0048] Comparative Example 3 The difference from Example 4 is that when the shell-type supported Ni-based catalyst is applied to high-pressure fixed-bed hydrogenation reaction, other conditions remain unchanged, and the mass space velocity is increased to 6h -1 . The catalyst performance does not show obvious decrease, the conversion of 3-hydroxypropanal is 96.2%, and the selectivity of 1,3-PDO is 98%.

[0049] As can be seen from Comparative Example 3, although the mass space velocity is increased, the specific surface area and pore volume, and the pore diameter of the catalyst are maintained during the reaction, effectively inhibiting the polymerization and covering of the active component during the reaction, and the good mechanical strength also improves the impact resistance of the bed, so that the catalyst performance is not affected too much.

[0050] Comparative Example 4 The difference from Example 2 is that in step S1, the concentration of TBAB in the nickel nitrate solution is 10wt.%, and the concentration of PVA is 15wt.%. The physical property test results of the catalyst prepared in Comparative Example 4 are shown in Table 1.

[0051] The catalyst obtained in Comparative Example 4 is applied to high-pressure fixed-bed hydrogenation reaction, the concentration of 3-hydroxypropanal solution is 15wt.%, the reaction pressure is 3MPa, the reaction temperature is 50℃, and the mass space velocity is 4h -1 . The conversion of 3-hydroxypropanal is 80.5%, and the selectivity of 1,3-PDO is 92.6%.

[0052] As can be seen from Comparative Example 4, adding an excess of peptizing agent to the nickel nitrate impregnation solution will make the viscosity of the system too large, the capillary action in the porous material is weakened, and the active component solution is difficult to penetrate into the micropores of the catalyst carrier. The active component is more aggregated on the outer surface of the catalyst carrier, and after drying and calcination, the active component is agglomerated, resulting in a decrease in the catalytic performance, and finally the conversion of 3-hydroxypropanal and the selectivity of 1,3-PDO decrease synchronously.

[0053] Comparative Example 5 The difference from Example 2 is that the mass ratio of the impregnation solution to the catalyst carrier in step S2 is 5:1 by increasing the amount of deionized water in the impregnation solution while keeping the amount of active components unchanged.

[0054] The catalyst obtained in Comparative Example 5 was applied to high-pressure fixed-bed hydrogenation reaction, the concentration of 3-hydroxypropanal solution was 15wt.%, the reaction pressure was 3 MPa, the reaction temperature was 50°C, and the mass space velocity was 4h -1 The conversion rate of 3-hydroxypropanal was 78.5%, and the selectivity of 1,3-PDO was 90.2%.

[0055] As can be seen from Comparative Example 5, when the content of deionized water in the impregnation solution is too high while keeping the absolute content of active components unchanged, the excessive deionized water will damage the stability of the catalyst carrier during the spraying process, which will indirectly cause the mechanical strength of the catalyst surface to weaken, increase the attrition during the impregnation process, and the calculated attrition is >8%, the uniformity of Ni on the catalyst surface is affected, which leads to the synchronous decrease of the conversion rate of 3-hydroxypropanal and the selectivity of 1,3-PDO.

[0056] Comparative Example 6 The difference from Example 2 is that the spraying disc 2 of the vacuum drum impregnator in Example 1 is replaced by a conventional spraying disc 2 structure in step S2, that is, the spraying disc 2 is arranged with spraying holes on the disc surface and no turbine is arranged inside the spraying disc 2.

[0057] The catalyst obtained in Comparative Example 6 was applied to high-pressure fixed-bed hydrogenation reaction, the concentration of 3-hydroxypropanal solution was 15wt.%, the reaction pressure was 3 MPa, the reaction temperature was 50°C, and the mass space velocity was 4h -1 The conversion rate of 3-hydroxypropanal was 82.7%, and the selectivity of 1,3-PDO was 95.9%.

[0058] As can be seen from Comparative Example 6, the controllability of the impregnation solution droplets formed in the drum 1 is poor, and the impregnation effect is poor when the conventional spraying disc 2 structure is used. After the catalyst carrier is taken out after impregnation, it can be seen with the naked eye that the catalyst carrier surface is impregnated with uneven mottling distribution. After multiple impregnation and treatment, the active components appear regional agglomeration and sintering, and the shell type distribution is poor, but the active components are also dispersed on the outer surface of the catalyst carrier, so that the conversion rate of 3-hydroxypropanal is reduced to 82.7%, and the selectivity of 1,3-PDO is still maintained above 95% although it is partially affected.

[0059] Comparative Example 7 The difference from Example 2 is that the impregnation process adopts a traditional immersion impregnation method: the catalyst carrier is soaked in the impregnation solution for 3 h, the mass ratio of the impregnation solution to the catalyst carrier is 3:1, and a catalyst precursor is obtained; then the catalyst precursor is dried at 120℃ for 8 h, aged at 180℃ for 12 h, and calcined at 750℃ for 8 h in sequence, and the catalyst is obtained.

[0060] The catalyst obtained in Comparative Example 7 is applied to a high-pressure fixed-bed hydrogenation reaction, the concentration of 3-hydroxypropanal solution is 15wt.%, the reaction pressure is 3 MPa, the reaction temperature is 50℃, the mass space velocity is 4h -1 , the conversion rate of 3-hydroxypropanal is 47.5%, and the selectivity of 1,3-PDO is 76.5%.

[0061] As can be seen from Comparative Example 7, the supported Ni catalyst prepared by the traditional immersion impregnation method is once over-impregnated, the impregnation solution fully infiltrates the catalyst carrier and deeply enters the interior of the catalyst carrier, the active component appears regional agglomeration and sintering, and the shell-type structure does not exist. In the reaction process, 3-hydroxypropanal and its hydrogenation by-products are easy to self-polymerize and block the pore channel in the deep high-temperature zone of the catalyst core, which seriously affects the mass transfer and heat transfer, and the conversion rate of 3-hydroxypropanal and the selectivity of 1,3-PDO appear a large decrease.

[0062] The physical property detection method of the catalysts prepared in Examples 2-4 and Comparative Examples 1-7 is as follows: the specific surface area and pore structure properties of the sample are analyzed by using the ASAP 2020 Plus type automatic adsorption instrument of Micromeritics (Shanghai) Instrument Co., Ltd., the sample is placed in a nitrogen adsorption desorption instrument, degassed at 300℃ in a vacuum environment for 6 h to remove the moisture on the surface of the sample and the adsorbed gas, and then measured. Among them, the specific surface area is calculated by using the BET method, and the pore size and pore volume are calculated by using the BJH method. The mechanical strength is measured by using a desktop YHKC-2A type digital catalyst strength tester, 200 catalysts are randomly selected and averaged. The catalyst particle size is tested by using a fine vernier caliper, 100 catalysts are randomly selected and averaged. The detection results are shown in Table 1: Table 1 Physical property detection results of the catalysts of Examples 2-4 and Comparative Examples 1-7

[0063] In summary, the physical and chemical properties of the shell-type supported Ni-based catalyst prepared by the present application are stable, the catalyst is used for 3-hydroxypropanal hydrogenation reaction, the equivalent of catalyst loading is lower under the same reaction efficiency, that is, the catalyst has a higher mass space velocity, the reaction conditions are mild, the conversion rate of raw materials is higher, and the selectivity of products is higher.

Claims

1. A method for preparing a shell-type supported Ni-based catalyst, characterized in that: The following steps are involved: S1: heating and stirring nickel salt, surfactant, deionized water and peptizing agent to obtain an impregnation solution; the surfactant is sodium lauryl polyether sulfate, sodium fatty alcohol polyoxyethylene ether sulfate or Tween 80; the peptizing agent is two of cetyltrimethylammonium bromide, tetrabutylammonium bromide, sodium α-olefin sulfonate, polyethylene glycol, carboxymethyl cellulose and polyvinyl alcohol; S2: pumping the impregnation liquid into a vacuum drum impregnator, and placing the catalyst support in the vacuum drum impregnator, spraying and impregnating to obtain a primary impregnation catalyst precursor; the mass ratio of the impregnation liquid to the catalyst support is (0.5-1):1; the catalyst support is a molecular sieve catalyst support made of one or two of silicon, aluminum and carbon; The vacuum drum impregnator comprises a drum (1), the drum (1) is provided with a feed port (101), the drum (1) is connected to the rotating shaft of a motor (3), the drum (1) is connected to a vacuum pump, and an electric heating wire is provided on the drum (1); a spray plate (2) is provided in the drum (1), the spray plate (2) is connected to a liquid inlet pipe (4), the liquid inlet pipe (4) is installed on the drum (1) through a bearing, and the liquid inlet pipe (4) is connected to the rotating shaft of a motor (5); a catalyst carrier is placed in the drum (1), and an impregnation liquid is sprayed on the surface of the catalyst carrier through the spray plate (2); a turbine is provided in the spray plate (2), and a spray needle tube (201) is provided on the spray plate (2) from the center to the outer edge, and the spray needle tube (201) is inclined outward; the rotation direction of the drum (1) and the spray plate (2) are opposite, and the rotation speed of the spray plate (2) is 15000~30000r / min; S3: drying, aging and calcining the primary impregnation catalyst precursor to obtain a primary impregnation catalyst; S4: The catalyst is impregnated once and then the above-mentioned spraying, drying, aging and calcining operations are repeated several times to obtain a shell-type supported Ni-based catalyst.

2. The method for preparing a shell-type supported Ni-based catalyst as claimed in claim 1, wherein In step S1, the nickel salt is nickel nitrate, nickel sulfamate or nickel acetylacetonate.

3. The method for preparing a shell-type supported Ni-based catalyst as claimed in claim 1, wherein In step S1, the nickel salt concentration in the impregnation solution is 0.01-2 mol / L.

4. The method for preparing a shell-type supported Ni-based catalyst according to claim 1, wherein In step S1, the concentration of the surfactant in the impregnation solution is 0.6-1 wt.%.

5. The method for preparing a shell-type supported Ni-based catalyst according to claim 1, wherein In step S1, the mass of the peptizing agent is 0.15-0.7% of the mass of the catalyst support.

6. The method for preparing a shell-type supported Ni-based catalyst according to claim 1, wherein In step S2, during the spraying and impregnation, the spray droplet diameter is 100-800 μm; the rotation speed of the drum (1) is 150-200 r / min, the temperature is 60-90° C., and the vacuum degree is -0.25-0.2 MPa.

7. The method for preparing a shell-type supported Ni-based catalyst according to claim 1, wherein In step S3 and step S4, the drying temperature is 80-150°C, the drying time is 1-24 hours, the aging temperature is 100-300°C, the aging time is 1-48 hours, the calcination temperature is 350-850°C, and the calcination time is 1-12 hours; in step S4, the Ni content of the obtained shell-type supported Ni-based catalyst is 1.5-5wt.%.

8. Shell-type supported Ni-based catalyst, characterized in that The catalyst is prepared by the method for preparing a shell-type supported Ni-based catalyst according to any one of claims 1 to 7.

9. Use of the shell-type supported Ni-based catalyst as claimed in claim 8, characterized in that, Shell-type supported Ni-based catalysts are used in the hydrogenation of 3-hydroxypropionaldehyde at a reaction pressure of 2-8 MPa, a reaction temperature of 30-100°C, and a mass space velocity of 1-5 h -1 .

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