Preparation process of oil ammonia column alumina carrier with high specific surface area

Abstract

The invention discloses a preparation process of an oil ammonia column alumina carrier with a high specific surface area, and aims to solve the problem that the specific surface area of spherical alumina prepared by an existing oil ammonia column forming method is less than 300m < 2 > / g. The process comprises the following steps: dissolving 0.5-2wt% of a nonionic surfactant in water, adding 24-36wt% of organic aluminum alkoxide, stirring at 60-80 DEG C for 1-2 hours, adding acid to adjust the pH value to 3.0-3.5, and continuously stirring for 2-4 hours to form alumina sol; dropwise adding the sol into an oil ammonia column to form gel beads; and aging the gel beads in 8-15wt% of ammonia water for 4-8 hours, washing with water, drying at 105 DEG C, and roasting at 500-850 DEG C. The specific surface area of the prepared alumina carrier reaches 385-428 m < 2 > / g, and the alumina carrier is high in sphericity degree, high in balling rate, excellent in mechanical strength and suitable for industrial catalysis scenes, and the process is easy to industrialize.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of industrial catalysis, and particularly discloses a preparation process of an oil-ammonia column alumina carrier with high specific surface area. BACKGROUND

[0002] In the field of industrial catalysis, the performance of a catalyst directly determines the reaction efficiency, product selectivity and production stability. As a carrier matrix of active components, the physical and chemical properties of a catalyst carrier have a key influence on the overall performance of the catalyst. Alumina has become one of the most widely used catalyst carriers in industry due to its excellent chemical stability, suitable surface acidity and good economy.

[0003] An industrial catalyst carrier needs to meet multiple dimensional requirements. On the one hand, it needs to have good mechanical strength and a regular shape to reduce the pressure drop of the reactor bed, optimize gas-liquid distribution and improve the flowability of materials. Among them, spherical alumina has become the mainstream carrier form due to its smooth surface, strong wear resistance and good uniformity of filling. On the other hand, the specific surface area of the carrier is a core index affecting the catalytic activity. A high specific surface area can provide more active sites, promote the adsorption and diffusion of reactant molecules, reduce the mass transfer resistance, and thus significantly improve the catalytic reaction efficiency.

[0004] At present, among the molding methods of spherical alumina, the oil-ammonia column molding method is the most widely used in industrial production due to its high sphericity, strong controllability of particle size and good process stability. However, the spherical alumina carriers prepared by the existing oil-ammonia column molding process generally have the technical bottleneck of low specific surface area. For example, the related patent technology with the publication number CN118255377A synthesizes high-purity pseudo-boehmite by using an organic aluminum alcohol method, and then the pseudo-boehmite is doped in an aluminum sol to form an oil-ammonia column. Although the alumina pellets obtained by the method have large pore volume, high sphericity and high purity, the specific surface area of the product is always less than 300 m 2 / g. Another patent technology with the publication number CN111517347A mixes low-sodium pseudo-boehmite and large-pore pseudo-boehmite and combines oil-ammonia column molding. Although the mechanical strength of the alumina spheres is greatly improved, the specific surface area is still limited to less than 300 m 2 / g.

[0005] The limitations of the above-mentioned existing technologies make it difficult for the spherical alumina carrier to fully play a role in catalytic scenarios that require high active sites, thereby restricting the further improvement of the industrial catalytic efficiency. Therefore, it is a key requirement to develop a process based on the oil-ammonia column molding method for stably preparing spherical alumina carriers with high specific surface area, which solves the current technical problems. SUMMARY

[0006] In view of the technical problem of low specific surface area of the spherical alumina carrier prepared by the existing oil-ammonia column forming method, the present application provides a high specific surface area oil-ammonia column alumina carrier preparation process, which aims to optimize the raw material system and accurately control the process parameters, on the basis of ensuring high sphericity, high purity and good mechanical strength of the carrier, significantly improve the specific surface area, and meet the application requirements of high activity catalytic scene.

[0007] The technical solution of the present application is as follows: the present application provides a high specific surface area oil-ammonia column alumina carrier preparation process, and the specific steps are as follows: Raw material system configuration: non-ionic surfactant and organic aluminum alcohol are used as core raw materials, the non-ionic surfactant is dissolved in deionized water at a concentration of 0.5-2wt%, and the organic aluminum alcohol is added to the above solution at a concentration of 24-36wt%; the non-ionic surfactant is selected from at least one of polyvinyl alcohol (PVA), polyethylene glycol (PEG) and Tween, and the organic aluminum alcohol is selected from at least one of isopropyl alcohol aluminum and tri-sec-butyl alcohol aluminum.

[0008] Alumina sol preparation: the above raw material mixing system is placed in a constant temperature environment of 60-80℃, and stirred for 1-2h to make the organic alcohol aluminum fully dissolved and initially dispersed; then add acid (such as concentrated nitric acid) to adjust the pH value of the system to 3.0-3.5, continue to stir for 2-4h, and form an alumina sol with uniform dispersion and good stability; accurate control of pH value and stirring time can avoid sol agglomeration, and lay a foundation for subsequent formation of porous structure.

[0009] Oil-ammonia column forming: the prepared alumina sol is uniformly dropped into the oil-ammonia column through the nozzle, the sol droplets form spherical droplets under the action of oil phase buoyancy and surface tension, then enter the ammonia phase and undergo gelation reaction to form alumina gel beads; the oil-ammonia column is composed of an upper oil phase and a lower ammonia phase, the oil phase is selected from at least one of kerosene, paraffin oil and mineral oil, the height of the oil phase is controlled to be 5-15cm, the ammonia phase is 8-15wt% ammonia water, the height of the ammonia phase is controlled to be 30-60cm, and the height ratio of the ammonia phase to the oil phase is 4-12; the oil-ammonia phase parameters can ensure the integrity of the droplet ball formation, and avoid gel bead adhesion.

[0010] Post-processing: the alumina gel beads formed in the oil-ammonia column are transferred to 8-15wt% ammonia water, and aged for 4-8h to enhance the structural stability of the gel beads; after aging, the gel beads are washed with water to remove residual impurities; then dried at 105℃ to remove free water and crystallization water in the gel beads; finally, the gel beads are calcined at 500-850℃ to convert the gel beads into alumina carrier with stable crystal structure.

[0011] In some embodiments, the non-ionic surfactant can be effectively regulated in a concentration range of 0.5-2 wt% to control the dispersibility of the sol and avoid particle agglomeration; and the organic aluminum alkoxide can be effectively regulated in a concentration range of 24-36 wt% to ensure the fluidity of the sol and provide sufficient aluminum source for forming a porous structure after subsequent calcination.

[0012] In some embodiments, the stirring temperature of 60-80 DEG C can promote the hydrolysis and dispersion of the organic aluminum alkoxide; the combination of the initial stirring of 1-2 h and the subsequent stirring of 2-4 h can ensure the uniformity of the sol system; and the acidic environment with a pH value of 3.0-3.5 can inhibit the rapid agglomeration of the aluminum oxide particles to form fine sol particles.

[0013] In some embodiments, the oil phase height of 5-15 cm can ensure that the droplets are fully spherical; the ammonia phase height of 30-60 cm and the ammonia water concentration of 8-15 wt% can ensure that the gel reaction is sufficient; and the ammonia / oil phase height ratio of 4-12 can balance the falling speed of the droplets and the gel reaction time to avoid deformation or incomplete structure of the gel beads.

[0014] In some embodiments, the drying temperature of 105 DEG C can gently remove moisture to avoid the collapse of the structure of the gel beads; and the calcination temperature range of 500-850 DEG C can ensure the crystallization of the aluminum oxide particles while retaining the porous structure between the particles to finally form a high specific surface area carrier.

[0015] The present application has the following beneficial effects relative to the prior art: Through the synergistic optimization of the raw material system and the process parameters, the specific surface area of the aluminum oxide carrier prepared by the present application can reach 385-428 m 2 / g, which is much higher than the level of <300 m 2 / g in the prior art, and can provide more active sites to significantly improve the adsorption and catalytic efficiency of the catalyst on the reactants, and is particularly suitable for fine catalytic reaction scenarios that require high active sites.

[0016] While improving the specific surface area, the process of the present application can still ensure the high sphericity and high purity of the carrier, and through the regulation of the aging and calcination processes, the mechanical strength of the carrier meets the requirements of the industrial reactor bed filling and material flow, avoiding the problems of carrier breakage or bed blockage caused by insufficient strength.

[0017] The raw materials used in the present application are all industrial-grade conventional raw materials, which are easy to obtain and have controllable cost; and the process parameters are all controllable values in a wide range, which do not require extreme conditions, are convenient for industrial scale-up production, can quickly adapt to the modification and upgrading of existing oil-ammonia column forming production lines, and reduce the threshold for industrial application.

[0018] The high specific surface spherical alumina carrier prepared by the application can be used as a carrier for hydrogenation, dehydrogenation, oxidation, denitration and other industrial catalytic reactions, and has significant application advantages and market value in the fields of high specific surface area requirements such as tail gas deep treatment and fine chemical synthesis. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the application will be clearly and completely described in combination with the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0020] Example 1 1. Raw material preparation: accurately weigh 10.0 g of polyvinyl alcohol (PVA, analytical pure), 240.0 g of aluminum isopropyl alcohol (chemically pure), 750.0 g of deionized water (conductivity < 5 μS / cm), and 68 wt% concentrated nitric acid (analytical pure); 2. Sol preparation: dissolve 10.0 g of PVA in 750.0 g of deionized water, control the stirring speed to 300 r / min, and after the PVA is dissolved and clarified, add 240.0 g of aluminum isopropyl alcohol. The mixed system is placed in a constant temperature water bath, and the temperature is set to 70°C. Keep the temperature stirring for 1.5 h; then slowly add 68 wt% concentrated nitric acid with stirring until the pH value of the system is stable at 3.2 (real-time monitoring with a precision of 0.01 pH meter), continue to keep 70°C, 300 r / min stirring for 3 h, and form a transparent and uniform alumina sol; 3. Oil-ammonia column forming: the oil-ammonia column is a glass column with an inner diameter of 5 cm and a height of 100 cm. The upper oil phase is 10.0 cm high kerosene (industrial grade, density 0.82 g / cm³), and the lower ammonia phase is 30.0 cm high 8.0 wt% ammonia water (prepared by 25 wt% concentrated ammonia water and deionized water). The alumina sol is loaded into a separatory funnel, the outlet flow rate of the funnel is controlled at 2 drops per second, and the sol droplets are vertically dropped into the oil-ammonia column through a stainless steel nozzle with a pore size of 0.5 mm. The sol droplets are buffered by the oil phase and then enter the ammonia phase to form alumina gel beads with a diameter of about 2 mm; 4. Post-treatment: The alumina gel beads were collected from the bottom of the oil-ammonia column and transferred to a sealed container containing 8.0 wt% ammonia water, and then aged statically at room temperature (25 °C) for 6 h. After aging, the gel beads were washed by suction filtration with deionized water, 500 mL of deionized water was added each time, and the gel beads were stirred for 10 min before being suction filtered. The washing was repeated 5 times until the pH of the washing liquid was stable at 7.0. The washed gel beads were placed in a drying oven, the temperature was set to 105 °C, and the drying time was 4 h. Finally, the dried sample was transferred to a muffle furnace, the temperature ramping rate was set to 5 °C / min, and the temperature was raised to 550 °C, and then the sample was held at this temperature for 6 h. The sample was naturally cooled to room temperature to obtain the finished alumina carrier.

[0021] Example 2 1. Raw material preparation: 10.0 g of PVA, 360.0 g of aluminum isopropoxide, 750.0 g of deionized water, and 68 wt% concentrated nitric acid were weighed; 2. Sol preparation: 10.0 g of PVA was dissolved in 750.0 g of deionized water, the stirring speed was 300 r / min, 360.0 g of aluminum isopropoxide was added, the temperature of the constant temperature water bath was set to 75 °C, and stirring was performed for 1.2 h. 68 wt% concentrated nitric acid was added dropwise to adjust the pH to 3.3, and stirring was continued at 75 °C and 300 r / min for 2.5 h to prepare a transparent alumina sol; 3. Oil-ammonia column formation: The oil phase height was 10.0 cm, the ammonia phase height was 30.0 cm, the nozzle aperture was 0.5 mm, and the flow rate was 2 drops / second, and gel beads with a diameter of about 2 mm were formed; 4. Post-treatment: The aging time was 5 h (8.0 wt% ammonia water, 25 °C), the water washing was performed 5 times (500 mL of deionized water each time), the drying temperature was 105 °C, the drying time was 4 h, the muffle furnace temperature was 550 °C, the calcination time was 6 h (temperature ramping rate was 5 °C / min), and the finished alumina carrier was obtained.

[0022] Example 3 1. Raw material preparation: 20.0 g of PVA, 240.0 g of aluminum isopropoxide, 750.0 g of deionized water, and 68 wt% concentrated nitric acid were weighed; 2. Sol preparation: 20.0 g of PVA was dissolved in 750.0 g of deionized water (stirring speed was 350 r / min to ensure complete dissolution of the PVA), 240.0 g of aluminum isopropoxide was added, the temperature of the constant temperature water bath was set to 65 °C, and stirring was performed for 1.8 h. 68 wt% concentrated nitric acid was added dropwise to adjust the pH to 3.1, and stirring was continued at 65 °C and 350 r / min for 3.5 h to prepare a uniform alumina sol; 3. Oil-ammonia column formation: The oil phase height was 10.0 cm, the ammonia phase height was 30.0 cm, the nozzle aperture was 0.5 mm, and the flow rate was 2 drops / second, and gel beads were formed; 4. Post-treatment: aging time 6h (8.0wt% ammonia water, 25℃), water washing 5 times, 105℃ drying 4h, 550℃ calcination 6h (heating rate 5℃ / min), to get the finished product of alumina carrier.

[0023] Example 4 1. Raw material preparation: weigh 10.0g PVA, 240.0g aluminum isopropoxide, 750.0g deionized water, 68wt% concentrated nitric acid; 2. Sol preparation: exactly the same as Example 1, 70℃ stirring for 1.5h, pH adjusted to 3.2, continue stirring for 3h, to prepare alumina sol; 3. Oil-ammonia column shaping: consistent with Example 1, oil phase 10.0cm, ammonia phase 30.0cm, nozzle aperture 0.5mm, flow rate 2 drops / second, to form gel beads; 4. Post-treatment: aging 6h (8.0wt% ammonia water, 25℃), water washing 5 times, 105℃ drying 4h; muffle furnace heating rate 5℃ / min, heating to 650℃ and then constant temperature calcination 6h, natural cooling, to get the finished product of alumina carrier.

[0024] Example 5 1. Raw material preparation: weigh 10.0g PVA, 240.0g aluminum isopropoxide, 750.0g deionized water, 68wt% concentrated nitric acid; 2. Sol preparation: 70℃ constant temperature water bath, 300r / min stirring for 1.5h, adjust pH to 3.2 after adding aluminum isopropoxide, continue stirring for 3h, to prepare alumina sol; 3. Oil-ammonia column shaping: oil phase is 5.0cm height of kerosene, ammonia phase is 60.0cm height of 15.0wt% ammonia water (ammonia oil ratio 12:1), nozzle aperture 0.5mm, flow rate 1.5 drops / second, to form gel beads with diameter about 1.8mm; 4. Post-treatment: aging 6h in 15.0wt% ammonia water (25℃), water washing 5 times, 105℃ drying 4h, 550℃ calcination 6h (heating rate 5℃ / min), to get the finished product of alumina carrier.

[0025] Example 6 1. Raw material preparation: weigh 15.0g polyethylene glycol (PEG-6000, analytical pure), 300.0g aluminum tri-sec-butylate (chemically pure), 750.0g deionized water, 98wt% concentrated sulfuric acid (analytically pure, diluted to 10wt% for use); 2. Sol preparation: 15.0 g PEG-6000 was dissolved in 750.0 g deionized water (stirring speed 280 r / min, temperature 70 °C), 300.0 g aluminum tri-sec-butoxide was added, stirring at 70 °C for 1.5 h; 10 wt% dilute sulfuric acid was added dropwise to adjust the pH to 3.2, and stirring was continued at 70 °C for 3 h at 280 r / min to prepare an alumina sol; 3. Oil-ammonia column forming: the oil phase was 12.0 cm height of paraffin oil (industrial grade, density 0.89 g / cm3), the ammonia phase was 48.0 cm height of 12.0 wt% ammonia water (ammonia / oil ratio 4:1), the nozzle aperture was 0.6 mm, and the flow rate was 2 drops / second to form gel beads with a diameter of about 2.2 mm; 4. Post-processing: aging in 12.0 wt% ammonia water for 5 h (25 °C), water washing 5 times, drying at 105 °C for 4 h, and calcining at 600 °C for 6 h (heating rate 5 °C / min) to obtain the finished product of the alumina carrier.

[0026] Comparative Example 1 1. Raw material preparation: 10.0 g PVA, 240.0 g low-sodium pseudoboehmite (Na2O content <0.1 wt%), 750.0 g deionized water, 68 wt% concentrated nitric acid; 2. Sol preparation: 10.0 g PVA was dissolved in 750.0 g deionized water (300 r / min, 70 °C), 240.0 g low-sodium pseudoboehmite was added, and stirring was continued at 70 °C for 2 h; 68 wt% concentrated nitric acid was added dropwise to adjust the pH to 3.2, and stirring was continued at 70 °C for 3 h to prepare a milky white mixed sol; 3. Oil-ammonia column forming: consistent with Example 1, the oil phase was 10.0 cm, the ammonia phase was 30.0 cm, the nozzle aperture was 0.5 mm, and the flow rate was 2 drops / second to form gel beads; 4. Post-processing: aging in 8.0 wt% ammonia water for 6 h, water washing 5 times, drying at 105 °C for 4 h, and calcining at 550 °C for 6 h to obtain the finished product of the alumina carrier.

[0027] Comparative Example 2 1. Raw material preparation: consistent with Example 1, 10.0 g PVA, 240.0 g aluminum isopropoxide, 750.0 g deionized water, 68 wt% concentrated nitric acid; 2. Sol preparation: consistent with Example 1, stirring at 70 °C for 1.5 h, pH 3.2, and stirring for 3 h to prepare an alumina sol; 3. Oil-ammonia column forming: the oil phase was 3.0 cm height of kerosene, the ammonia phase was 9.0 cm height of 8.0 wt% ammonia water (ammonia / oil ratio 3:1), the nozzle aperture was 0.5 mm, and the flow rate was 2 drops / second to form irregular gel beads (partially adhered); 4. Post-treatment: consistent with Example 1, aging for 6 h, water washing for 5 times, drying at 105 ℃ for 4 h, and calcination at 550 ℃ for 6 h, to obtain the finished product of the alumina carrier.

[0028] Comparative Example 3 1. Raw material preparation: 30.0 g of PVA, 240.0 g of aluminum isopropoxide, 750.0 g of deionized water, and 68 wt% concentrated nitric acid were weighed; 2. Sol preparation: 30.0 g of PVA was dissolved in 750.0 g of deionized water (350 r / min, 70 ℃, and the dissolution time was extended to 2 h), 240.0 g of aluminum isopropoxide was added, and stirring was performed at 70 ℃ for 1.5 h; 68 wt% concentrated nitric acid was added dropwise to adjust the pH to 3.2, and stirring was continued for 3 h, to obtain an alumina sol with slight agglomeration; 3. Oil-ammonia column shaping: consistent with Example 1, the oil phase was 10.0 cm, the ammonia phase was 30.0 cm, the nozzle aperture was 0.5 mm, and the flow rate was 2 drops / second, to form gel beads with uneven sizes; 4. Post-treatment: consistent with Example 1, aging for 6 h, water washing for 5 times, drying at 105 ℃ for 4 h, and calcination at 550 ℃ for 6 h, to obtain the finished product of the alumina carrier.

[0029] Comparative Example 4 1. Raw material preparation: consistent with Example 1, 10.0 g of PVA, 240.0 g of aluminum isopropoxide, 750.0 g of deionized water, and 68 wt% concentrated nitric acid were weighed; 2. Sol preparation: consistent with Example 1, to obtain a transparent alumina sol; 3. Oil-ammonia column shaping: consistent with Example 1, to form uniform gel beads; 4. Post-treatment: aging for 6 h, water washing for 5 times, drying at 105 ℃ for 4 h, and calcination at 900 ℃ for 6 h at a temperature rising rate of 5 ℃ / min, and natural cooling, to obtain the finished product of the alumina carrier.

[0030] Performance verification Specific surface area test (BET method) Instrument: full-automatic specific surface area and porosity analyzer; Sample pretreatment: 0.5 g of each alumina carrier sample was taken and placed in a sample tube, and was degassed at 120 ℃ and a vacuum degree <10 - 3 Pa for 4 h; Test conditions: liquid nitrogen temperature (196.15 ℃), nitrogen adsorption-desorption isotherm determination range of relative pressure (P / P0) 0.01-0.99, specific surface area was calculated by using the Brunauer Emmett Teller (BET) model, and the data accuracy was ±1 m 2 / g.

[0031] Sphericity and spheroidization rate test Sphericity: using a metallographic microscope, magnification 200 times, randomly selecting 100 carrier particles, measuring the long axis diameter (L) and short axis diameter (D) of each particle using image analysis software (ImageProPlus6.0), calculating the sphericity (sphericity = D / L), taking the average value, precision ±0.01; Spheroidization rate: counting the total amount of sol drops (1000 drops), collecting the number of complete spherical gel beads (sphericity ≥0.90), calculating the spheroidization rate (spheroidization rate = complete spherical gel bead number / 1000 × 100%), precision ±1%.

[0032] Mechanical strength test Instrument: particle compressive strength tester; Test method: randomly selecting 20 carrier particles, placing each particle on the test platform, applying pressure at a speed of 1mm / min, recording the maximum pressure value when the particle breaks, taking the average value, precision ±1N / particle.

[0033] The performance verification results are as follows:

[0034] Examples 1-6 strictly follow the "raw material system-process parameters" synergistic scheme defined in the application: 24-36wt% organic alcohol aluminum as aluminum source, 0.5-2wt% nonionic surfactant as dispersant, preparing sol under the condition of 60-80℃ and adjusting pH to 3.0-3.5, forming through an oil-ammonia column with oil phase height 5-15cm and ammonia phase height 30-60cm (ammonia / oil ratio 4-12), combining with post-processing processes of 105℃ drying and 500-850℃ calcination, the finally prepared alumina carriers all present excellent and stable performance: The specific surface area significantly breaks through the bottleneck of the prior art, reaching 385-428m 2 / g, which is more than 30% higher than the product prepared by the existing oil-ammonia column forming process <300m 2 / g, which can fully meet the demand for "multiple active sites" in high-activity catalytic scenarios; The comprehensive performance is balanced, the sphericity is maintained at 0.95-0.97 (close to ideal sphericity), the spheroidization rate reaches 96%-99%, and the mechanical strength is 91-98N / particle, which completely meets the use requirements of "low pressure drop, high flowability, and anti-crushing" for industrial reactor bed filling, proving that the process of the application does not sacrifice the core application performance of the carrier while improving the specific surface area.

[0035] Comparative Example 1 uses the low-sodium pseudo-boehmite commonly used in the prior art to replace the organic alcohol aluminum of the application, and the rest of the process parameters are completely consistent with Example 1, and the final carrier specific surface area is only 282m 2 / g, which proves that "organic alcohol aluminum" is the core aluminum source for realizing high specific surface area in the present application, and it cannot break through the performance bottleneck by replacing traditional pseudo-boehmite; Comparative Example 2 reduces the oil phase height to 3 cm, adjusts the ammonia oil ratio to 3, and the rest of the conditions are consistent with Example 1. Not only is the specific surface area reduced to 275 m 2 / g, and the balling rate also drops from 98% to 72%, and the sphericity drops to 0.82, which proves that the limitation of "oil phase height 5-15 cm, ammonia oil ratio 4-12" is a double guarantee for "balling quality and high specific surface area", and deviation from this range will simultaneously cause the molding effect and performance to deteriorate; Comparative Example 3 increases the non-ionic surfactant concentration to 3 wt% (exceeding the upper limit of 0.5-2 wt% of the present application), and the sol appears obvious agglomeration, and the final carrier specific surface area is only 291 m 2 / g, which proves that the surfactant concentration range defined in the present application can precisely control the sol dispersibility, and too high concentration will cause particle agglomeration and destroy the porous structure; Comparative Example 4 uses the high temperature calcination of 900℃ commonly used in the prior art (higher than the upper limit of 850℃ of the present application), although the mechanical strength is increased to 125 N / particle, but the specific surface area is reduced to 268 m 2 / g, which proves that the limitation of "calcination temperature 500-850℃" is the key to balance the degree of crystallization and the retention of porous structure, and high temperature calcination will cause the collapse of the pore structure, and cannot realize high specific surface area.

[0036] In summary, the present application precisely limits "raw material type and concentration, sol preparation conditions, oil ammonia column molding parameters, post-processing temperature", and constructs a synergistic process system. The alumina carrier prepared by the present application realizes a breakthrough in specific surface area, and the comprehensive performance meets the industrial application requirements. At the same time, the results of the comparative examples fully prove that the process limitation of the present application is not a simple combination or parameter adjustment of the prior art, but a necessary technical feature for realizing "high specific surface area" target, which has outstanding substantial features and significant progress, and fully meets the requirements of patent inventiveness.

[0037] The above only describes the preferred embodiments of the present application and does not limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A process for the preparation of high specific surface oil ammonia column alumina support, characterized by, The method comprises the following steps: (1) Sol preparation: non-ionic surfactant is dissolved in water at a concentration of 0.5-2wt%, and organic alcohol aluminum with a concentration of 24-36wt% is added, stirring at 60-80℃ for 1-2h, then adding acid to adjust the pH to 3.0-3.5, and continuing to stir for 2-4h to form an alumina sol; wherein the organic alcohol aluminum is selected from at least one of aluminum isopropoxide and aluminum tri-sec-butylate, and the non-ionic surfactant is selected from at least one of polyvinyl alcohol, polyethylene glycol and Tween; (2) Oil-ammonia column forming: the alumina sol obtained in step (1) is dropped into the oil-ammonia column through a nozzle to form alumina gel beads; the oil-ammonia column comprises an upper oil phase and a lower ammonia phase, the oil phase is selected from at least one of kerosene, paraffin oil and mineral oil, the height of the oil phase is 5-15cm, the ammonia phase is 8-15wt% ammonia water, the height of the ammonia phase is 30-60cm, and the height ratio of the ammonia phase to the oil phase is 4-12; (3) Post-treatment: the alumina gel beads obtained in step (2) are aged in 8-15wt% ammonia water for 4-8h, then washed with water, dried at 105℃, and finally calcined at 500-850℃ to obtain an oil-ammonia column alumina carrier with high specific surface area.

2. The process for preparing high specific surface area oil ammoxidized alumina support according to claim 1, characterized in that, The organic alcohol aluminum in step (1) is aluminum isopropoxide.

3. The process for preparing high surface area oil ammoximation alumina support according to claim 1, wherein, The non-ionic surfactant in step (1) is polyvinyl alcohol.

4. The process for preparing high surface area oil ammoximation alumina support according to claim 1, wherein, The acid in step (1) is concentrated nitric acid.

5. The process for preparing high surface area oil ammoximation alumina support according to claim 1, wherein, The oil phase of the oil-ammonia column in step (2) is kerosene.

6. The process for preparing high surface area oil ammoximation alumina support according to claim 1, wherein, The height of the ammonia phase of the oil-ammonia column in step (2) is 30cm, the height of the oil phase is 10cm, and the height ratio of the ammonia phase to the oil phase is 3.

7. The process for preparing high surface area oil ammoximation alumina support according to claim 1, wherein The aging time of the alumina gel beads in step (3) is 6h.

8. The process for preparing high surface area oil ammoximation alumina support according to claim 1, wherein, The calcination temperature in step (3) is 550-650℃.

9. The process for preparing high surface area oil ammoximation alumina support according to claim 1, wherein, The calcination time in step (3) is 6h.

10. The process for preparing high surface area oil ammoximation alumina support according to claim 1, wherein, The prepared alumina support has a specific surface area of 385-428 m 2 / g.

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