Titanium-containing alumina support, process for its preparation and use thereof

Abstract

The application relates to the technical field of catalyst carriers, and discloses a titanium-containing alumina carrier as well as a preparation method and application thereof. The titanium-containing alumina carrier contains alumina and titanium oxide, the pore volume of the carrier is 0.5-1 mL / g, the proportion of the pore volume distribution of 6-13 nm in the total pore volume in the carrier is greater than 75%, and the pore concentration degree of the carrier is 1-1.8. The carrier has a high pore concentration degree and effective pore diameter proportion, and is especially suitable for use in a residual oil hydrogenation catalyst, and improves the performance of the catalyst.

Description

Technical Field

[0001] This invention relates to the technical field of catalyst supports, specifically to a titanium-containing alumina support, its preparation method, and its application. Background Technology

[0002] The pore structure of the hydrogenation catalyst support and its interaction with the active metal significantly influence catalytic performance. To develop next-generation hydrogenation catalysts with superior performance, the properties of the support material must be considered. TiO2 is a commonly used oxide support. Due to its structural characteristics, it can promote the sulfidation reduction of oxidized metals. Hydrodesulfurization catalysts prepared using titanium dioxide as a support exhibit high reactivity and good anti-coking properties. However, the small specific surface area and pore volume of titanium dioxide supports, along with relatively poor thermal stability, limit their application as catalyst supports. Combining titanium dioxide with alumina can effectively improve thermal stability and significantly improve the pore structure, resulting in higher reactivity in the hydrodesulfurization reaction. Existing titanium-containing alumina supports synthesized via co-precipitation have low pore concentration and a high proportion of micropores, which is detrimental to the hydrodesulfurization reaction.

[0003] Patent application CN101890342A discloses a titanium-containing alumina carrier and its preparation method. This carrier is prepared using aluminum hydroxide sol (prepared via a molten salt supersol-colloid method) as raw material, with the addition of a titanium-containing slurry, followed by molding, drying, and calcination. During the preparation process, because the aluminum hydroxide gel contains surfactants and hydrocarbon components, the molding and calcination result in rod-shaped nano-alumina with large pore volume and diameter, but a high proportion of small pores and a low pore concentration.

[0004] Patent application CN1344586A discloses a supported nano-TiO2 composite carrier and its preparation method. This method involves preparing a titanium sol by mixing tetrabutyl titanate with ethanol, water, and nitric acid. The titanium sol is then added to a slurry prepared by mixing boehmite with water or anhydrous ethanol. The sample is then air-dried for 24 hours, dried at 60°C for 12 hours, dried at 120°C for 4 hours, and subsequently calcined at 200°C, 300°C, 400°C, and 500°C for 2 hours each. This method enables the loading of nano-TiO2 onto macroporous alumina. XRD results indicate that the nano-TiO2 has anatase crystal structure.

[0005] Patent application CN111050904A discloses a series of methods for synthesizing titanium-aluminum composite oxide supports, including co-extrusion, co-precipitation, continuous stepwise precipitation, and impregnation. The co-precipitation method involves simultaneously adding aluminum sulfate and titanium oxysulfate mixed in a fluid, along with sodium aluminate, to water at 60°C and pH 8.5. The flow rates of sodium aluminate and aluminum sulfate / titanium oxysulfate are kept constant, and the pH is maintained constant using NaOH or H₂SO₄. After the addition is complete, the pH is raised to 10, and the material is aged, then filtered, washed, dried, and calcined to obtain the titanium-aluminum composite oxide material. The titanium-aluminum support prepared by this method has a relatively high TiO₂ content (mass ratios of 20.9% and 48.0%, respectively), and exhibits characteristic peaks of anatase in the XRD results.

[0006] The co-precipitation method described above cannot obtain titanium dioxide-containing alumina supports with uniform dispersion and high pore concentration. When loading nano-titanium dioxide onto alumina supports via the sol-gel method, the synthesis process is complex and cannot be achieved using inexpensive and readily available raw materials and simple methods. Summary of the Invention

[0007] The purpose of this invention is to overcome the problems existing in the prior art and provide a titanium-containing alumina support, its preparation method and application. This support has a high pore concentration and effective pore size ratio, and is especially suitable for use in residue oil hydrogenation catalysts to improve catalyst performance.

[0008] To achieve the above objectives, the first aspect of the present invention provides a titanium-containing alumina carrier, wherein the carrier contains alumina and titanium oxide, the pore volume of the carrier is 0.5-1 mL / g, the proportion of pore volume distribution of 6-13 nm in the carrier to the total pore volume is greater than 75%, and the pore concentration of the carrier is 1-1.8.

[0009] Preferably, by XRD analysis, the support did not show diffraction peaks of titanium oxide, and the alumina was in a γ-crystalline state.

[0010] A second aspect of the present invention provides a method for preparing a titanium-containing alumina carrier, wherein the method includes the following steps:

[0011] (1) A gelling reaction is carried out between an acidic solution containing aluminum and titanium and an alkaline solution containing aluminum to obtain a solid gelling product;

[0012] (2) In the presence of a precipitant, the solid gelling product described in step (1) is subjected to a first aging and a second aging in sequence, and then subjected to a first drying to obtain a titanium-containing alumina precursor. The temperature of the second aging is lower than that of the first aging.

[0013] (3) The titanium-containing alumina precursor described in step (2) is mixed with a binder and an extrusion aid to form a mold, and then subjected to a second drying and calcination to obtain a titanium-containing alumina carrier.

[0014] The third aspect of this invention provides the application of the titanium-containing alumina support described in the first aspect or the titanium-containing alumina support prepared by the preparation method described in the second aspect in a residue oil hydrodesulfurization catalyst.

[0015] The titanium-containing alumina support provided by this invention has both a high pore concentration and a pore distribution ratio of 6-13nm effective pores, as well as a large pore volume. In preferred cases, the titanium oxide is more uniformly dispersed in the support, which is especially suitable for use in residue oil hydrotreating catalysts to improve the hydrodesulfurization performance of residue oil.

[0016] Compared with the prior art, the preparation method provided by this invention uses a two-stage aging process (co-precipitation method) to prepare a titanium-containing alumina support. A titanium source is introduced into an acidic solution, which allows titanium to be more uniformly dispersed in the titanium-containing alumina support. After two stages of aging, the pore distribution ratio and pore concentration of 6-13 nm effective pores in the support can be improved. Furthermore, the method provided by this invention is simple, uses inexpensive and readily available raw materials, and has easily controllable operating conditions. Detailed Implementation

[0017] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0018] The first aspect of the present invention provides a titanium-containing alumina support, wherein the support contains alumina and titanium oxide, the pore volume of the support is 0.5-1 mL / g, the proportion of pore volume of 6-13 nm in the support to the total pore volume is greater than 75%, and the pore concentration of the support is 1-1.8.

[0019] The titanium-containing alumina support provided by this invention has both a high pore concentration and a pore distribution ratio of 6-13nm effective pores, as well as a large pore volume, making it particularly suitable for use in residue oil hydrotreating catalysts to improve the hydrodesulfurization performance of residue oil.

[0020] In this invention, the pore structure of the carrier was determined by N2 adsorption-desorption method. The specific test conditions were as follows: N2 adsorption-desorption characterization was performed on a Micromeritics ASAP 2420 adsorption instrument. Before the test, 0.3g of the carrier was taken and pretreated at 350℃ under vacuum for 10 hours.

[0021] In this invention, the pore concentration is defined as the highest DV value (DV) in the BET pore size distribution map-DV curve. MAXThe ratio of the peak width at half maximum (FWHM) to the peak width at half maximum (P0 = DV) is called P0 = DV. MAX / FWHM.

[0022] In this invention, preferably, based on the total amount of the carrier, the content of alumina in the carrier is 70-99% by weight, and the content of titanium oxide is 0.5-29.5% by weight; more preferably, based on the total amount of the carrier, the content of alumina is 74-96% by weight, and the content of titanium oxide is 3.5-25.5% by weight.

[0023] In this invention, it should be noted that the carrier may optionally contain impurities. This invention does not particularly limit the types of impurities. When the carrier contains impurities, the total content of the impurities, alumina, and titanium oxide meets the requirement of 100%.

[0024] In this invention, the content of each component in the carrier was measured using a Rigaku Electric Industries, Ltd. 3271 X-ray fluorescence spectrometer.

[0025] In this invention, preferably, the pore volume of the support is 0.6-0.8 mL / g. The support provided by this invention has a large pore volume, making it particularly suitable for residue hydrotreating catalysts and improving the hydrodesulfurization performance of residue oil.

[0026] In this invention, preferably, the proportion of 6-13 nm pore volume distribution in the support accounts for 78-95% of the total pore volume. The support provided by this invention, while maintaining a high pore volume, can improve the pore volume distribution of 6-13 nm, ensuring the support has a high effective pore size. It is particularly suitable for residue hydrotreating catalysts, helping to improve the diffusion and reaction performance of reactants on the catalyst, and improving the hydrodesulfurization performance of residue oil; in the prior art, the proportion of 6-13 nm pore volume distribution is usually below 70%.

[0027] In this invention, preferably, the carrier does not contain pores smaller than 2 nm. The advantage of this preferred embodiment is that it effectively reduces the proportion of small pores in the carrier.

[0028] In this invention, preferably, the pore concentration of the support is 1.2-1.6. The support provided by this invention has a high pore volume and a high pore distribution ratio of 6-13 nm. At the same time, the support has a high pore concentration, ensuring that the support has a high effective pore size, which is particularly suitable for residue hydrotreating catalysts and improves the hydrodesulfurization performance of residues. In the prior art, the pore concentration is usually below 0.6, and the proportion of effective pores is low, which is not conducive to improving the reaction performance of reactants on the catalyst.

[0029] In this invention, preferably, the specific surface area of ​​the carrier is 200-400 m².2 / g, preferably 210-350m 2 / g.

[0030] In this invention, preferably, the most probable pore size of the carrier is 4-13 nm, more preferably 6-12 nm. The advantage of this preferred embodiment is that it helps to increase the proportion of effective pores in the carrier.

[0031] In this invention, preferably, the L-acid content of the support is 120-175 μmol / L, more preferably 140-155 μmol / L. The support provided by this invention has a low L-acid content, which can effectively reduce carbon deposition in the catalyst prepared from the support, which is beneficial to the hydrogenation reaction and improves the performance of the hydrogenation catalyst.

[0032] In this invention, the acid content of the carrier was determined by pyridine infrared spectroscopy. Specific test conditions were as follows: pyridine infrared spectroscopy (FT-IR) characterization was performed using a Nicolet 6700 Fourier transform infrared spectrometer with a DTGS detector, 32 scans, and a resolution of 4 cm⁻¹. -1 The sample was compressed to 10 mg / cm³. -2 The self-supporting sheet was tested at 450℃ (heating rate 50℃·min). -1 ), calcined in situ for 1 hour. Afterwards, the IR cell was evacuated at this temperature until P < 10. -3 Pa, maintained for 3 hours, the sample was cooled to 25°C, and the first spectrum was acquired. Pyridine vapor was introduced into the infrared cell and maintained for 15 minutes to reach adsorption equilibrium. Vacuum desorption was performed at 200°C for 20 minutes (10 -3 Pa) pyridine, then the sample was cooled to 25°C and the spectrum was collected. The peak areas of the two peaks were used to calculate... The amount of Lewis acid center, 1545cm -1 The peak at that location corresponds to the adsorption on Vibration of the pyridine ion at the acid center, 1450 cm⁻¹ -1 The peak at that point corresponds to the vibration of the pyridine molecule coordinated to the Lewis acid center.

[0033] In this invention, preferably, XRD analysis shows that no diffraction peaks of titanium oxide were observed in the support. XRD analysis also indicates that titanium oxide is uniformly dispersed in the material, demonstrating good dispersibility.

[0034] In this invention, preferably, the alumina is in a γ-crystalline state.

[0035] In this invention, the crystal structure of the titanium-containing alumina carrier was determined using a Philips XPERT series X-ray powder diffractometer. The specific test conditions were as follows: Cu Kα rays (Kα = 0.154 nm), working current 30 mA, working voltage 40 kV, Ni filter, and scanning range 2θ = 5°-70°.

[0036] A second aspect of the present invention provides a method for preparing a titanium-containing alumina carrier, wherein the method includes the following steps:

[0037] (1) A gelling reaction is carried out between an acidic solution containing aluminum and titanium and an alkaline solution containing aluminum to obtain a solid gelling product;

[0038] (2) In the presence of a precipitant, the solid gelling product described in step (1) is subjected to a first aging and a second aging in sequence, and then subjected to a first drying to obtain a titanium-containing alumina precursor. The temperature of the second aging is lower than that of the first aging.

[0039] (3) The titanium-containing alumina precursor described in step (2) is mixed with a binder and an extrusion aid to form a mold, and then subjected to a second drying and calcination to obtain a titanium-containing alumina carrier, wherein the carrier contains alumina and titanium oxide.

[0040] During the research process, the inventors of this invention discovered that by using an acidic titanium-containing solution as the titanium source, and by reacting an acidic titanium-containing and aluminum-containing solution with an alkaline aluminum-containing solution to form a gel, followed by two aging processes, a titanium-containing alumina precursor can be obtained. This titanium-containing alumina precursor can be used to prepare a titanium-containing alumina carrier with high pore concentration and a high proportion of 6-13 nm pore volume.

[0041] The method provided by this invention, which obtains a dried product after two aging processes, can improve the crystallinity and grain uniformity of titanium-containing alumina materials, and is beneficial to improving the pore concentration of the carrier.

[0042] The method provided by this invention enables titanium dioxide to be uniformly dispersed in a carrier. The reaction process is simple, easy to operate, uses inexpensive and readily available raw materials, requires no organic reagents, and is environmentally friendly in production.

[0043] In this invention, preferably, in step (1), the acidic solution containing aluminum and titanium is prepared by mixing a solution containing titanium compound dissolved with an acidic aluminum solution, or by dissolving the titanium compound in an acidic aluminum solution.

[0044] In this invention, the type of titanium-containing compound is not particularly limited. Preferably, the titanium-containing compound is at least one selected from titanium oxysulfate, titanium sulfate, and metatitanic acid. By selecting titanium-containing compounds within the above range to prepare an acidic solution containing titanium and aluminum for gelation reaction, the use of organic titanium reagents is avoided, ensuring that the entire preparation process is simple and environmentally friendly.

[0045] In this invention, preferably, the dissolution conditions include a temperature of 35-60°C and a time of 0.15-72 hours. By adopting this preferred embodiment, the titanium-containing compound can be better dissolved in the solution and the hydrolysis of titanium can be prevented by controlling the dissolution conditions. When the dissolution temperature is too high or too low, the titanium-containing compound will hydrolyze in the solution, and the titanium cannot be uniformly dispersed in the material.

[0046] In this invention, the type of acidic aluminum solution is not particularly limited. Preferably, the acidic aluminum solution is selected from at least one of aluminum sulfate solution, aluminum nitrate solution, and aluminum chloride solution.

[0047] In this invention, the content of aluminum and titanium in an acidic solution containing aluminum and titanium within a specific range is obtained by controlling the amount of titanium-containing compound and the amount of acidic aluminum solution used. Preferably, in step (1), the concentration of the acidic solution containing aluminum and titanium, calculated as alumina, is 20-150 g / L, more preferably 30-130 g / L, and even more preferably 45-65 g / L.

[0048] In this invention, the content of aluminum and titanium in an acidic solution containing aluminum and titanium within a specific range is obtained by controlling the amount of titanium-containing compound and the amount of acidic aluminum solution used. Preferably, in step (1), the concentration of the acidic solution containing aluminum and titanium, calculated as titanium oxide, is 5-80 g / L, more preferably 6-70 g / L, and even more preferably 6-30 g / L.

[0049] In this invention, the type of alkaline aluminum-containing solution is not particularly limited. Preferably, in step (1), the alkaline aluminum-containing solution is a sodium aluminate solution and / or a potassium aluminate solution.

[0050] In this invention, preferably, in step (1), the concentration of the alkaline aluminum-containing solution, calculated as alumina, is 50-300 g / L.

[0051] In this invention, preferably, the amounts of the acidic solution containing aluminum and titanium and the alkaline aluminum-containing solution are such that the content of aluminum oxide in the prepared titanium-containing alumina carrier is 70-99% by weight, preferably 74-96% by weight, and the content of titanium oxide is 0.5-29.5% by weight, preferably 3.5-25.5% by weight.

[0052] In this invention, preferably, in step (1), the gelation reaction is carried out continuously or intermittently, preferably continuously. Continuous gelation is more conducive to controlling the pH during the gelation reaction, effectively improving the quality of the titanium-containing alumina carrier.

[0053] The present invention does not particularly limit the equipment used for the gelation reaction, and any conventional choice in the art can be used. Specifically, for example, it can be carried out in a gelation tank.

[0054] According to a specific embodiment of the present invention, the continuous gelation reaction process of the present invention includes: pre-entering a certain amount of deionized water into a gelation tank, and introducing the acidic solution containing titanium and aluminum and the alkaline aluminum-containing solution from the top of the gelation tank, so that the acidic solution and the alkaline aluminum-containing solution are mixed to form a gel, and the slurry generated by the gelation reaction continuously flows out of the gelation tank, keeping the liquid level in the gelation tank constant.

[0055] In this invention, preferably, in step (1), the conditions for the gelation reaction include: a temperature of 50-70℃, a pH value of 5-7, and a reaction time of 0.1-1h. By carrying out the gelation reaction under acidic conditions, the formation of impurities in gibbsite can be effectively avoided, thus improving product quality.

[0056] In this invention, preferably, the second aging temperature is 10-80°C lower than the first aging temperature, more preferably 25-75°C lower, and even more preferably 30-50°C lower. The advantage of this preferred embodiment is that it can improve the crystallinity and grain uniformity of the titanium-containing alumina material.

[0057] In this invention, the conditions for the first aging are not particularly limited. Preferably, in step (2), the conditions for the first aging include: a temperature of 60-100℃, preferably 80-98℃, a time of 2-12h, preferably 4-8h, and a pH of 7-11, preferably 7.5-10.5.

[0058] In this invention, the conditions for the second aging are not particularly limited. Preferably, in step (2), the conditions for the second aging include: a temperature of 20-70°C, preferably 40-65°C, a time of 0.5-12h, preferably 1-8h, and a pH of 7-11, preferably 7.5-10.5.

[0059] In this invention, the pH value of the reaction system is adjusted by adding a precipitant, so that the slurry obtained from the solid gelling product in step (1) undergoes an aging reaction. This invention does not specifically limit the type of precipitant. In step (2), the precipitant is an alkali metal compound, preferably selected from at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate.

[0060] In this invention, the amount of precipitant is not particularly limited, as long as it meets the pH required for two aging reactions. Those skilled in the art can adjust it according to the actual situation.

[0061] In this invention, the methods of the first and second aging are not particularly limited. According to a preferred embodiment of the invention, step (2) includes: subjecting the solid gelling product of step (1) to a first aging to obtain a first aging product; separating and washing the solid and liquid components of the first aging reaction to obtain a filter cake; and then pulping the filter cake and subjecting it to a second aging. Preferably, step (2) uses water (preferably deionized water) to pulp the first aging product before subjecting it to the second aging. In this invention, the amount of water used is such that the concentration of the slurry obtained after pulping, based on the weight of oxides (total amount of aluminum oxide and titanium oxide), is 50-180 g / L, preferably 70-150 g / L.

[0062] According to another preferred embodiment of the present invention, step (2) includes: subjecting the solid gelling product of step (1) to a first aging to obtain a first aging product, and subjecting the first aging product to a second aging.

[0063] In this invention, preferably, step (2) further includes: performing solid-liquid separation on the product obtained from the second aging process, obtaining a solid product, then pulping the solid product to obtain a slurry, and then performing a first drying on the slurry to obtain a titanium-containing alumina precursor. In this invention, the solid-liquid separation is a conventional operation in the art, specifically, for example, it can be at least one of sedimentation, filtration, and centrifugation. In this invention, preferably, step (2) further includes washing the solid product before drying. The washing operation described in this invention can be a conventional operation in the art, and those skilled in the art can choose according to actual needs, as long as it can reduce the content of impurity ions (e.g., residual sodium and sulfate) in the solid aging product, for example, so that the sodium oxide content in the titanium-containing alumina obtained by calcining the titanium-containing alumina precursor is less than 0.1 wt%, preferably less than 0.06 wt%, more preferably 0.01-0.05 wt%, and the sulfate content is less than 2 wt%, preferably less than 1 wt%.

[0064] In this invention, the method of the first drying is not particularly limited; for example, it can be spray drying as conventionally defined in the art. The conditions for the first drying are not particularly limited, as long as free water can be removed. Preferably, the conditions for the first drying include a temperature of 80-200°C, more preferably 100-150°C.

[0065] In this invention, the type of adhesive solvent is not particularly limited, and adhesive solvents conventionally defined in the art are applicable to this invention. Preferably, in step (3), the adhesive solvent is selected from at least one of nitric acid, hydrochloric acid, and citric acid.

[0066] In this invention, the amount of adhesive solvent is not particularly limited, and those skilled in the art can select it according to actual needs.

[0067] In this invention, the type of extrusion aid is not particularly limited, and any adhesive solvent conventionally defined in the art can be applied to this invention. In step (3), the extrusion aid is selected from at least one of guar gum powder, cellulose, and starch.

[0068] In this invention, the amount of extrusion aid is not particularly limited, and those skilled in the art can select it according to actual needs.

[0069] In this invention, the conditions for the second drying are not particularly limited, and those skilled in the art can select them according to actual needs.

[0070] In this invention, the roasting conditions are not particularly limited. Preferably, in step (3), the roasting conditions include: a temperature of 400-700℃ and a time of 3-6h.

[0071] The third aspect of this invention provides the application of the titanium-containing alumina support described in the first aspect or the titanium-containing alumina support prepared by the preparation method described in the second aspect in a residue oil hydrodesulfurization catalyst.

[0072] The present invention will be described in detail below through embodiments. Unless otherwise specified, all raw materials used in the following embodiments are commercially available products.

[0073] The composition of the titanium-containing alumina carrier was determined by measuring the characteristic spectral lines of each element using a Rigaku Electric Co., Ltd. 3271 X-ray fluorescence spectrometer. The elemental content of the titanium-containing alumina was semi-quantitatively analyzed using the external standard method, yielding the composition of Al2O3, TiO2, SO3, Na2O, etc. in the sample.

[0074] The N2 adsorption-desorption characterization method was as follows: N2 adsorption-desorption characterization was performed on a Micromeritics ASAP 2420 nitrogen adsorption instrument. Before the test, about 0.3g of titanium-containing alumina was taken and pretreated under vacuum at 350℃ for 10 hours. The pore volume was determined by the single-point adsorption method, and the specific surface area of ​​the sample was calculated using the BET equation.

[0075] The pore structure of the carrier was determined by N2 adsorption-desorption method. The specific test conditions were as follows: N2 adsorption-desorption characterization was performed on a Micromeritics ASAP2420 adsorption instrument. Before the test, 0.3 g of the carrier was taken and pretreated at 350 °C under vacuum for 10 hours.

[0076] The definition of pore concentration is: the highest DV value in the BET pore size distribution map-DV curve (DV). MAX The ratio of the peak width at half maximum (FWHM) to the peak width at half maximum (P0 = DV) is called P0 = DV. MAX / FWHM.

[0077] Example 1

[0078] (1) Take 1.8L of deionized water, add titanium oxysulfate while heating and stirring. The heating temperature is 55℃ and the time is 0.5h. The titanium oxysulfate dissolves to obtain an acidic titanium-containing solution. Add the acidic titanium-containing solution to 2.2L of aluminum sulfate solution to obtain an acidic solution containing aluminum and titanium. Add 3L of deionized water to the gelling tank in advance. Pass the acidic solution containing aluminum and titanium and sodium aluminate solution into the gelling tank from the top of the gelling tank so that the acidic solution containing aluminum and titanium and sodium aluminate solution are mixed in the gelling tank to carry out the gelling reaction. The slurry after the gelling reaction flows out from the overflow pipe of the gelling tank. The liquid level in the gelling tank remains unchanged. When the pre-added deionized water is replaced by the slurry after the gelling reaction, the slurry is collected to obtain the gelling reaction product.

[0079] The concentration of sodium aluminate solution (calculated as alumina) was 220 g / L, and the flow rate was 40 g / min. The concentration of titanium oxide in the acidic titanium-containing solution was 6.58 g / L, and the concentration of alumina was 55 g / L. By adjusting the flow rate of the acidic solution to 120-130 g / min, the pH value of the gelation reaction was made to be 6.5, the temperature of the gelation reaction was 58℃, and the reaction time was 0.5 h.

[0080] (2) Sodium carbonate was added to adjust the pH of the gelation reaction product to 9.4, and then the gelation product was aged. The conditions for the first aging treatment were a temperature of 93°C and a time of 5h. The first aging product was filtered into a slurry and then washed with deionized water to obtain a filter cake. Deionized water was then added to make a slurry for the second aging. The temperature of the second aging was 50°C and the time was 3h to obtain an aged mixture. The concentration of the slurry was 85g / L based on titanium oxide-alumina.

[0081] The aging mixture was subjected to solid-liquid separation to obtain a solid aging product. The solid aging product was then mixed with an appropriate amount of deionized water to form a slurry. The slurry was spray-dried using a Buqi B290 to obtain a titanium-containing alumina precursor S1. This material was then calcined at 600°C for 3 hours to obtain titanium oxide-alumina Al. The specific physicochemical properties are listed in Table 1.

[0082] (3) Take 100g of titanium-containing alumina precursor S1 powder, add 100g of deionized water, 3g of guar gum powder and 1.8mL of concentrated nitric acid and mix evenly. Knead in an extruder, extrude into strips, dry at 120℃ for 8 hours, and calcine in a tube furnace at 600℃ for 3 hours to obtain titanium-containing alumina carrier ZT1. The specific physicochemical properties are listed in Table 1.

[0083] XRD characterization of the titanium-containing alumina support ZT1 showed γ-Al2O3 diffraction peaks at 37°, 45°, and 67°, but no titanium oxide crystal diffraction peaks were observed, indicating that titanium was uniformly dispersed in the support.

[0084] Example 2

[0085] The method is the same as in Example 1, except that in step (1), acidic solutions containing aluminum and titanium with different titanium oxide contents are used. Specifically, the titanium oxide concentration is 12.34 g / L, the aluminum oxide concentration is 58 g / L, and the flow rate is 110-120 g / min. The other conditions are the same as in Example 1.

[0086] (2) Same as in Example 1, titanium-containing alumina precursor S2 was obtained. After S2 was calcined at 600°C for 3 hours, titanium oxide-alumina A2 was obtained. The specific physicochemical properties of titanium oxide-alumina A2 are listed in Table 1.

[0087] (3) Take 100g of titanium-containing alumina precursor S2 powder, add 95g of deionized water, 3g of guar powder and 2mL of concentrated nitric acid and mix evenly. Knead in an extruder, extrude into strips, dry at 120℃ for 8 hours, and calcine in a tube furnace at 600℃ for 3 hours to obtain titanium-containing alumina carrier ZT2. The specific physicochemical properties are listed in Table 1.

[0088] Comparative Example 1

[0089] Titanium-containing alumina precursor CS1 was prepared according to the method of Example 2, except that the aging pH was 8.7, no second aging was performed after the first aging, and the aging temperature was 90°C for 4 hours. The mixture from the first aging was filtered, washed, and spray-dried to obtain titanium-containing alumina precursor CS1. Then, the precursor was calcined at 600°C for 3 hours to obtain titanium oxide-alumina CA1. Then, 100g of titanium-containing alumina precursor CS1 powder was taken and extruded according to the same method as in Example 2 to obtain titanium-containing alumina carrier CZT1.

[0090] Comparative Example 2

[0091] Following the method of Example 2, a titanium-free alumina precursor CS2 was prepared, except that titanium oxysulfate was not added to the acidic solution, the aging pH was 8.7, no second aging was performed after the first aging, and the aging temperature was 90°C for 4 hours. The mixture from the first aging was filtered, washed, and spray-dried to obtain boehmite CS2. Then, the precursor was calcined at 600°C for 3 hours to obtain alumina CA2. Then, 100g of boehmite CS2 powder was extruded and formed according to the same method as in Example 2 to obtain alumina carrier CZT2.

[0092] Example 3

[0093] (1) Take 1.8L of deionized water, add titanium oxysulfate while heating and stirring. The heating temperature is 45℃ and the time is 0.4h. After the titanium oxysulfate dissolves, add the acidic titanium-containing solution to 2.2L of aluminum sulfate solution to obtain an acidic solution containing aluminum and titanium. Add 3L of deionized water to the gelling tank in advance, and pass the acidic solution containing aluminum and titanium and sodium aluminate solution from the top of the gelling tank to mix the acidic solution containing aluminum and titanium and sodium aluminate solution in the gelling tank for gelling reaction. The slurry after the gelling reaction flows out from the overflow pipe of the gelling tank. The liquid level in the gelling tank remains unchanged. When the pre-added deionized water is replaced by the slurry after the gelling reaction, the slurry collection begins to obtain the gelling reaction product.

[0094] The concentration of sodium aluminate solution (calculated as alumina) was 200 g / L, and the flow rate was 45 g / min; the concentration of titanium oxide in the acidic solution was 26.85 g / L, and the concentration of alumina was 58 g / L. By adjusting the flow rate of the acidic solution to 120-130 g / min, the pH value of the gelation reaction was made 6.2; the temperature of the gelation reaction was 62℃, and the reaction time was 0.4 h.

[0095] (2) Sodium carbonate was added to adjust the pH of the gelation reaction product to 8.6, and then the gelation product was aged. The conditions for the first aging treatment were: temperature 90℃ and time 6h. The first aging product was filtered into a slurry and then washed with deionized water to obtain a filter cake. Deionized water was then added to make a slurry for the second aging. The temperature of the second aging was 60℃ and the time was 2h to obtain an aging mixture. The concentration of the slurry was 97g / L based on titanium oxide-alumina.

[0096] The aging mixture was subjected to solid-liquid separation to obtain a solid aging product. The solid aging product was then mixed with an appropriate amount of deionized water to form a slurry. The slurry was spray-dried using a Buqi B290 to obtain a titanium-containing alumina precursor S3. This material was then calcined at 600°C for 3 hours to obtain titanium oxide-alumina A3. The specific physicochemical properties are listed in Table 1.

[0097] (3) Take 100g of titanium-containing alumina precursor S3 powder, add 86g of deionized water, 3g of guar gum powder and 2.5mL of concentrated nitric acid and mix evenly. Knead in an extruder, extrude into strips, dry at 120℃ for 6 hours, and calcine in a tube furnace at 600℃ for 3 hours to obtain titanium-containing alumina carrier ZT3. The specific physicochemical properties are listed in Table 1.

[0098] Example 4

[0099] Titanium-containing alumina carriers were prepared according to the method of Example 2, (1) same as in Example 2.

[0100] (2) Sodium carbonate was added to adjust the pH of the gelation reaction product to 8.5, and then the gelation product was subjected to aging treatment. The conditions for the first aging treatment were a temperature of 71°C and a time of 8 hours. The remaining conditions were the same as in Example 2, and titanium-containing alumina precursor S4 was obtained. After S4 was calcined at 600°C for 3 hours, titanium oxide-alumina A4 was obtained. The specific physicochemical properties of titanium oxide-alumina A4 are listed in Table 1.

[0101] (3) Take 100g of titanium-containing alumina precursor S4 powder, add 95g of deionized water, 3g of guar gum powder and 2.2mL of concentrated nitric acid and mix evenly. Knead in an extruder, extrude into strips, dry at 120℃ for 8 hours, and calcine in a tube furnace at 600℃ for 3 hours to obtain titanium-containing alumina carrier ZT4. The specific physicochemical properties are listed in Table 1.

[0102] Example 5

[0103] Titanium-containing alumina carriers were prepared according to the method in Example 2.

[0104] (1) Same as Example 2.

[0105] (2) Sodium carbonate was added to adjust the pH of the gelation reaction product to 9.4, and then the gelation product was aged. The conditions for the first aging treatment were a temperature of 93°C and a time of 5h. The first aging product was filtered into a slurry and then washed with deionized water to obtain a filter cake. Deionized water was then added to make a slurry for the second aging. The temperature for the second aging was 30°C and the time was 0.6h to obtain an aged mixture. The concentration of the slurry was 85g / L based on titanium oxide-alumina.

[0106] The aging mixture was subjected to solid-liquid separation to obtain a solid aging product. The solid aging product was then mixed with an appropriate amount of deionized water to form a slurry. The slurry was spray-dried using a Buqi B290 to obtain a titanium-containing alumina precursor S5. This material was then calcined at 600°C for 3 hours to obtain titanium oxide-alumina A5. The specific physicochemical properties of titanium oxide-alumina A5 are listed in Table 1.

[0107] (3) Take 100g of titanium-containing alumina precursor S5 powder, add 95g of deionized water, 3g of guar gum powder and 2.2mL of concentrated nitric acid and mix evenly. Knead the mixture in an extruder, extrude it into strips, dry it at 120℃ for 8 hours, and calcine it in a tube furnace at 600℃ for 3 hours to obtain titanium-containing alumina carrier ZT5. The specific physicochemical properties are listed in Table 1.

[0108] Comparative Example 3

[0109] This embodiment uses the method described in patent application CN105170193A to prepare titanium dioxide-alumina composite oxide. 0.5 kg of titanium dioxide sulfate solution (TiO2 content 20% by mass) and 6.3 g of sodium sulfate were dissolved and stirred until homogeneous to obtain solution A. 5 kg of sodium aluminate solution (Al2O3 concentration 15% by mass) was prepared and stirred until homogeneous to obtain solution B.

[0110] Solution A was added to the gelation tank as the base liquid. Under stirring conditions at 40°C, solution B was slowly added to solution A. The addition rate was controlled so that solution B was added within 30 minutes. The final pH value of the reaction was 5. After neutralization, the mixture was stirred for 0.5 hours. The resulting slurry was added to the reaction vessel and hydrothermally treated at 190°C for 3 hours. After naturally cooling to 60°C, the slurry was subjected to solid-liquid separation. It was washed with deionized water at 60°C until neutral. The resulting filter cake was directly dried at 120°C for 3 hours to obtain CS3. It was then calcined at 600°C for 2 hours to obtain titanium-aluminum composite oxide powder CA3.

[0111] Take 100g of titanium-containing alumina precursor CS3 powder, add 95g of deionized water, 3g of guar gum powder and 2mL of concentrated nitric acid, mix evenly, knead in an extruder, extrude into strips, dry at 120℃ for 8 hours, and calcine in a tube furnace at 600℃ for 3 hours with air to obtain titanium-containing alumina carrier CZT3. The specific physicochemical properties are listed in Table 1.

[0112] Comparative Example 4

[0113] This embodiment uses the precipitation method described in patent application CN111050904A to prepare titanium dioxide-alumina composite oxide. Aluminum sulfate and titanium oxysulfate mixed in a single fluid, along with sodium aluminate, are simultaneously added to water at 60°C and pH 8.5. The flow rates of sodium aluminate and aluminum sulfate / titanium oxysulfate are kept constant, and the pH is controlled consistently using NaOH or H₂SO₄. The total feeding time is 1 hour, and the final concentration in the reactor is 4 wt%. The pH is then raised to approximately 10 with NaOH, and the slurry is aged for 20 minutes with stirring. The slurry is filtered through a filter cloth and washed with water until sodium and sulfate are completely removed. The filter cake is dried to obtain the titanium alumina precursor CS4. This material is calcined at 600°C for 3 hours to obtain titanium dioxide-alumina CA₄; its specific physicochemical properties are listed in Table 1. CS₄ is extruded and calcined at 650°C for 1 hour with a gas flow rate of 10 mL / min to obtain the titanium alumina support CZT₄; its specific physicochemical properties are listed in Table 1.

[0114] Comparative Example 5

[0115] (1) Add 3L of deionized water to the gelling tank in advance, add titanium oxysulfate to aluminum sulfate solution to prepare an acidic solution containing aluminum and titanium, and pass the acidic solution containing aluminum and titanium and sodium aluminate solution from the top of the gelling tank to mix the acidic solution containing aluminum and titanium and sodium aluminate solution in the gelling tank to carry out the gelling reaction. The slurry after the gelling reaction flows out from the overflow pipe of the gelling tank. The liquid level in the gelling tank remains unchanged. When the pre-added deionized water is replaced by the slurry after the gelling reaction, the slurry collection begins, and then the filter cake (solid gelling product) is obtained by filtration.

[0116] The concentration of sodium aluminate solution (calculated as alumina) was 200 g / L, and the flow rate was 42 g / min. The concentration of titanium oxide in the acidic solution containing aluminum and titanium was 12.89 g / L, and the concentration of alumina was 58 g / L. By adjusting the flow rate of the acidic solution containing aluminum and titanium to 115-125 g / min, the pH value of the gelation reaction was approximately 6.3, and the temperature of the gelation reaction was 60℃.

[0117] (2) The gelation reaction product was aged by adding sodium carbonate solution to adjust the pH of the aging treatment. The aging conditions were pH 9.0, temperature 90℃, and time 6h.

[0118] (3) The aged mixture was filtered and washed sequentially to remove residual sodium and sulfate. The resulting filter cake (solid aged product) was then added to deionized water and slurried. The concentration of the resulting slurry was 130 g / L based on the weight of the titanium dioxide-alumina composite oxide. The resulting slurry was subjected to hydrothermal treatment at 150°C for 4 hours. After hydrothermal treatment, it was spray-dried to obtain titanium-containing pseudoboehmite CS5, which was then calcined at 600°C for 2 hours to obtain titanium-alumina composite oxide powder CA5.

[0119] (4) Take 100g of titanium-containing pseudoboehmite CS5 and 3g of guar gum powder and mix them evenly. At room temperature, mix the mixture with 85ml of nitric acid aqueous solution with a volume concentration of 1.65% and mix evenly. Continue to knead the mixture into a plastic body on a twin-screw extruder and then extrude it into a butterfly strip with a diameter of 1.4 mm. After drying the wet strip at 120℃ for 4 hours, it is calcined at 550℃ for 3 hours to obtain carrier CZT5. The composition and properties of carrier CZT5 are shown in Table 1.

[0120] Comparative Example 6

[0121] Titanium-containing alumina carrier was prepared according to the method in Example 1.

[0122] (1) Same as Example 1.

[0123] (2) Sodium carbonate was added to adjust the pH of the gelation reaction product to 9.4. The gelation product was then subjected to aging treatment. The first aging treatment conditions were: temperature 60℃, time 5h. The first-aged product was filtered into a slurry, washed with deionized water to obtain a filter cake, and then further aging was performed by adding deionized water and beating the slurry. The second aging treatment was performed at 60℃ for 2h to obtain an aged mixture. The remaining conditions were the same as in Example 1. A titanium-containing alumina precursor CS6 was obtained. CS6 was calcined at 600℃ for 3 hours to obtain titanium oxide-alumina CA6. The specific physicochemical properties of titanium oxide-alumina CA6 are listed in Table 1.

[0124] (3) Take 100g of titanium-containing alumina precursor CS6 powder, add 95g of deionized water, 3g of guar gum powder and 2mL of concentrated nitric acid and mix evenly. Knead the mixture in an extruder, extrude it into strips, dry it at 120℃ for 8 hours, and calcine it in a tube furnace at 600℃ for 3 hours to obtain titanium-containing alumina carrier CZT6. The specific physicochemical properties are listed in Table 1.

[0125] Table 1

[0126]

[0127] As shown in Table 1, the carrier prepared by the method of this invention exhibits a pore volume distribution of 6-13 nm accounting for more than 75% of the total pore volume, a pore concentration of 1-1.8, and an L-acid concentration of 120-175 μmol / g. When the preparation conditions are within the preferred range described in this invention, the titanium-containing alumina carrier has superior pore volume and most probable pore size, with a high proportion of pore volume distribution in the 6-13 nm range and a high pore concentration. Compared with the comparative example, the method of this invention provides readily available and inexpensive raw materials for preparing the titanium-containing alumina carrier, and the preparation process is simple and short, yielding a titanium-containing alumina carrier with superior pore properties.

[0128] Test case

[0129] The titanium-containing alumina supports of the above examples and comparative examples were saturated with a mixed solution of ammonium molybdate heptahydrate, ammonia and cobalt nitrate to make them contain 15.0% by weight of molybdenum oxide and 3.2% by weight of cobalt oxide, respectively. After drying, they were calcined at 500°C for 3 hours to prepare hydrodesulfurization catalysts.

[0130] The catalysts prepared in the examples and comparative examples were crushed into particles with a diameter of 2-3 mm and loaded into a fixed-bed reactor for programmed temperature-controlled sulfidation: straight-run kerosene containing 2% dimethyl disulfide was used as the sulfiding oil, and the temperature was increased from 110°C to 230°C at a rate of 20°C / h and held for 6 hours; then the temperature was increased to 360°C at a rate of 20°C / h and held for 6 hours; then the desulfurization performance was evaluated. The feedstock composition was: Shanghai residual oil with a sulfur content of 4.02 wt% (density (20°C) 981.1 kg / m³). 3 The reaction conditions were: temperature 380℃, hydrogen partial pressure 14 MPa, and feedstock hourly space velocity 0.5 h⁻¹. -1 The hydrogen-to-oil volume ratio was 600:1. Samples were taken and analyzed after 1000 hours of operation. The activity data are shown in Table 2.

[0131] Table 2

[0132]

[0133]

[0134] As can be seen from the results in Table 2, when the titanium-containing alumina support prepared by the method provided in this invention is used to prepare the catalyst, the catalyst has better reactivity under the same conditions and can improve the desulfurization rate of the catalyst.

[0135] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A titanium-containing alumina carrier, characterized in that, The carrier contains aluminum oxide and titanium oxide, the pore volume of the carrier is 0.5-1 mL / g, the proportion of pore volume distribution of 6-13 nm in the carrier to the total pore volume is greater than 75%, and the pore concentration of the carrier is 1-1.

8.

2. The carrier according to claim 1, wherein, Based on the total amount of the carrier, the content of alumina is 70-99% by weight, and the content of titanium oxide is 0.5-29.5% by weight; Preferably, based on the total amount of the carrier, the content of alumina is 74-96% by weight, and the content of titanium oxide is 3.5-25.5% by weight; Preferably, the pore volume of the carrier is 0.6-0.8 mL / g; Preferably, the proportion of 6-13 nm pore volume distribution in the carrier to the total pore volume is 78-95%; Preferably, the pore density of the carrier is 1.2-1.

6.

3. The carrier according to claim 1 or 2, wherein, The specific surface area of ​​the carrier is 200-400 m². 2 / g; Preferably, the most probable pore size of the carrier is 4-13 nm, and more preferably 6-12 nm; Preferably, the L acid concentration of the carrier is 120-175 μmol / L, more preferably 140-155 μmol / L; Preferably, the support did not show diffraction peaks of titanium oxide as determined by XRD analysis. Preferably, the alumina is characterized by XRD analysis to be in a γ-crystalline state.

4. A method for preparing a titanium-containing alumina carrier, wherein, The method includes the following steps: (1) A gelling reaction is carried out between an acidic solution containing aluminum and titanium and an alkaline solution containing aluminum to obtain a solid gelling product; (2) In the presence of a precipitant, the solid gelling product described in step (1) is subjected to a first aging and a second aging in sequence, and then subjected to a first drying to obtain a titanium-containing alumina precursor. The temperature of the second aging is lower than that of the first aging. (3) The titanium-containing alumina precursor described in step (2) is mixed with a binder and an extrusion aid to form a mold, and then subjected to a second drying and calcination to obtain a titanium-containing alumina carrier, wherein the carrier contains alumina and titanium oxide.

5. The preparation method according to claim 4, wherein, In step (1), the acidic solution containing aluminum and titanium is prepared by mixing a solution containing titanium compound dissolved with an acidic aluminum solution, or by dissolving the titanium compound in an acidic aluminum solution. Preferably, the titanium-containing compound is at least one selected from titanium oxysulfate, titanium sulfate, and metatitanic acid; Preferably, the dissolution conditions include: a temperature of 35-60°C and a time of 0.15-72 hours; Preferably, the acidic aluminum solution is selected from at least one of aluminum sulfate solution, aluminum nitrate solution, and aluminum chloride solution; Preferably, in step (1), the concentration of the acidic solution containing aluminum and titanium, based on alumina, is 20-150 g / L, more preferably 30-130 g / L, and even more preferably 45-65 g / L; Preferably, in step (1), the concentration of the acidic solution containing aluminum and titanium, based on titanium oxide, is 5-80 g / L, more preferably 6-70 g / L, and even more preferably 6-30 g / L; Preferably, in step (1), the alkaline aluminum-containing solution is a sodium aluminate solution and / or a potassium aluminate solution; Preferably, in step (1), the concentration of the alkaline aluminum-containing solution, calculated as alumina, is 50-300 g / L; Preferably, the amounts of the acidic and alkaline aluminum-containing solutions containing aluminum and titanium are such that the aluminum content in the prepared titanium-containing alumina carrier is 70-99% by weight, preferably 74-96% by weight, and the titanium content is 0.5-29.5% by weight, preferably 3.5-25.5% by weight.

6. The method according to claim 4 or 5, wherein, In step (1), the gelation reaction is carried out continuously or intermittently, preferably continuously; Preferably, in step (1), the conditions for the gelation reaction include: a temperature of 50-70℃, a pH value of 5-7, and a reaction time of 0.1-1h.

7. The method according to claim 4 or 5, wherein, The temperature of the second aging is 10-80°C lower than that of the first aging, preferably 25-75°C lower, and even more preferably 30-50°C lower.

8. The method according to claim 4 or 5, wherein, In step (2), the conditions for the first aging include: a temperature of 60-100℃, preferably 80-98℃, a time of 2-12h, preferably 4-8h, and a pH of 7-11, preferably 7.5-10.5; Preferably, in step (2), the conditions for the second aging include: a temperature of 20-70°C, preferably 40-65°C, a time of 0.5-12h, preferably 1-8h, and a pH of 7-11, preferably 7.5-10.5; Preferably, in step (2), the precipitant is an alkali metal compound, preferably selected from at least one of sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate.

9. The method according to claim 4 or 5, wherein, The step (2) includes: subjecting the solid gelling product of step (1) to a first aging to obtain a first aging product; separating the solid and liquid of the first aging reaction, washing and obtaining a filter cake; and then pulping the filter cake and subjecting it to a second aging. Alternatively, step (2) may include: subjecting the solid gelling product of step (1) to a first aging process to obtain a first aging product, and subjecting the first aging product to a second aging process. Preferably, in step (3), the calcination conditions include: a temperature of 400-700℃ and a time of 3-6h.

10. The application of the titanium-containing alumina support according to any one of claims 1-4 or the titanium-containing alumina support prepared by the preparation method according to any one of claims 5-9 in the hydrodesulfurization catalyst of residue oil.

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