Alumina carrier, hydrogenation protective agent and preparation method thereof

Abstract

The present invention discloses an alumina carrier, a hydrogenation protective agent and a preparation method thereof. The alumina carrier of the present invention comprises an alumina substrate and curved lamellar alumina grown on the surface of the substrate, wherein the curved lamellar alumina has a length of 0.1-0.8 μm and a thickness of 10-20 nm; the curved lamellar alumina is accumulated to form pores of 100-500 nm. The preparation method of the alumina carrier of the present invention comprises the following contents: (1) impregnating the alumina substrate with an aluminum salt solution, followed by drying and calcining; (2) immersing the material calcined in step (1) in a sealed hydrothermal treatment in a propylene oxide aqueous solution, and drying and calcining the treated material to obtain an alumina carrier. The alumina carrier contains curved lamellar alumina, and the hydrogenation protective catalyst prepared using the alumina as a carrier has high decalcification and iron activity, as well as high nickel removal, vanadium removal and desulfurization activity.

Description

Technical Field

[0001] The present invention relates to the field of catalytic material preparation, and in particular to an alumina carrier, a hydrogenation protective agent and a preparation method thereof. Background Art

[0002] In the oil refining, petrochemical, and chemical industries, especially in fixed-bed hydrogenation reactors processing impure feedstocks like residual oil and coal tar, the primary solid deposits in these feedstocks are carbon deposits and metal sulfides. Some of these deposits enter the catalyst pores, while others settle on the outer surfaces of the catalyst particles. Over time, these deposits gradually increase the pressure drop across the catalyst bed, ultimately clogging the reactor. Therefore, to extend the operating cycle and service life of the primary catalyst in industrial plants, a certain level of hydrogenation protective agent must generally be placed above the primary catalyst bed in fixed-bed hydrogenation reactors.

[0003] There are many types of hydrogenation protective agents currently used in the market, with various specifications such as spherical, cylindrical, Raschig ring, impeller ring, honeycomb cylindrical, etc. Their shapes, sizes, materials, and activities are different, and their functions and effects are also different. For the hydrogenation protective agent loaded in the upper layer, its main function is to effectively filter and adsorb fine solid impurities in its raw oil and remove highly reactive organic metal impurities such as iron and calcium.

[0004] CN200510115349.0 discloses a hydrogenation active protective agent and its preparation method. The protective agent comprises an alumina carrier, an effective amount of a hydrogenation active metal component and a halogen supported on the carrier, wherein the halogen content is 0.5 wt% to 10 wt% based on the element and the catalyst, and the specific surface area of ​​the carrier is 2 to 50 m 2 / g, and a pore volume of 0.4-1.2 mL / g. The carrier is prepared by a method comprising mixing one or more alumina and / or alumina precursors with at least one halogen-containing compound, forming and calcining.

[0005] CN201110044282.1 discloses a hydrogenation active protective agent using an alkaline earth metal-containing alumina as a carrier, its preparation, and its application. The protective agent comprises an alkaline earth metal-containing alumina carrier and a hydrogenation active metal component supported on the carrier. The hydrogenation active metal component is a combination of at least one metal component selected from Group VIII and at least one metal component selected from Group VB. The content of the Group VIII metal component, calculated as oxide and based on the protective agent, is 0.2% to 15% by weight, and the content of the Group VB metal component is 0.2% to 15% by weight.

[0006] The calcination temperature in the preparation of hydrogenation protective agent carriers in the existing technology is relatively high, and the specific surface area of ​​the final catalyst is small. Although the catalyst can effectively remove metal impurities such as iron and calcium in the reactants, its ability to remove metal impurities such as nickel and vanadium needs to be improved. Summary of the Invention

[0007] In response to the shortcomings of the prior art, the present invention provides an alumina carrier, a hydrogenation protective agent, and a preparation method thereof. The alumina carrier contains curved lamellar alumina, and the hydrogenation protective catalyst prepared using the alumina as a carrier has high decalcification and iron activity, as well as high nickel, vanadium, and sulfur removal activity.

[0008] The alumina carrier of the present invention comprises an alumina substrate and curved lamellar alumina grown on the surface of the substrate, wherein the curved lamellar alumina has a length of 0.1-0.8 μm and a thickness of 10-20 nm; the curved lamellar alumina is accumulated to form pores of 100-500 nm, and the coverage of the curved lamellar alumina on the surface of the alumina skeleton is 90%-100%. Based on the weight of the carrier, the content of the curved lamellar alumina is 5%-15%.

[0009] The preparation method of the alumina carrier of the present invention comprises the following contents: (1) impregnating an alumina substrate with an aluminum salt solution, followed by drying and calcining; (2) immersing the material calcined in step (1) in a sealed hydrothermal treatment in a propylene oxide aqueous solution, and drying and calcining the treated material to obtain an alumina carrier.

[0010] In the method of the present invention, the aluminum salt solution in step (1) is an aqueous solution of aluminum nitrate, the concentration of aluminum nitrate is 10wt%-60wt%, preferably 20wt%-50wt%, the amount of aluminum salt solution used is such that the alumina substrate is completely immersed, and the immersion time is 0.5-2 hours. During the impregnation, a single impregnation or multiple impregnations can be used as needed, preferably multiple impregnations, and the number of impregnations is preferably 2 times or more. When multiple impregnations are used, drying and roasting treatments are required after each impregnation; the drying temperature is 100-160°C, the drying time is 2-10 hours, the roasting temperature is 450-550°C, and the roasting time is 4-10 hours.

[0011] In the method of the present invention, the alumina matrix described in step (1) is γ-alumina, which can be homemade or commercially purchased, and can be spherical, cylindrical, Raschig ring, impeller ring, honeycomb cylindrical, etc. The preparation method of the alumina matrix is ​​generally to mix, shape, dry and roast pseudo-boehmite, and the roasting temperature is generally 750-950°C. Other modifying elements, such as silicon, titanium, zirconium, alkali metals, alkaline earth metals, etc., can also be added as needed. The content of the modifying elements in terms of oxides is 0.1wt%-30wt%.

[0012] In the method of the present invention, the concentration of the propylene oxide aqueous solution in step (2) is 2.5wt%-12wt%, preferably 4wt%-8wt%, and the mass ratio of the propylene oxide aqueous solution to the material after calcination in step (1) is 3:1-10:1, preferably 4:1-8:1. More preferably, polyethylene glycol 2000-20000 is added to the propylene oxide aqueous solution at a mass ratio of the polyethylene glycol 2000-20000 to the carrier precursor material of 0.01:1-0.05:1.

[0013] In the method of the present invention, the sealed hydrothermal treatment in step (2) is carried out in a sealed container, which is preferably an autoclave. The treatment temperature is 110-180°C, preferably 120-160°C, and the treatment time is 4-8 hours. The pressure in the sealed container during the hydrothermal treatment is autogenous pressure.

[0014] In the method of the present invention, the drying temperature in step (2) is 100-160°C, and the drying time is 2-10 hours; the roasting temperature is 450-550°C, and the roasting time is 4-10 hours.

[0015] The present invention also provides a hydrogenation protective agent, which has a specific surface area of ​​40-120m 2 / g, a pore volume of 0.5-1.0 mL / g, pores with a diameter greater than 1 μm accounting for 10%-30% of the total pore volume, and pores with a diameter of 100-500 nm accounting for 25%-55% of the total pore volume; based on the weight of the catalyst, the content of the Group VIB metal component as oxide is 3.5%-8%, preferably 4.5%-7.5%, and the content of the Group VIII metal component as oxide is 0.5%-5.0%, preferably 1.5%-3.5%. The Group VIB metal component is W and / or Mo. The Group VIII metal component is Co and / or Ni.

[0016] The method for preparing a hydrogenation protective agent of the present invention comprises the following steps: impregnating the aforementioned alumina support with a solution of a hydrogenation-active component, and drying and calcining the impregnated support to produce the hydrogenation protective agent. The hydrogenation-active metal impregnation solution is a solution containing a Group VIB and / or Group VIII metal, and may be an acid solution, an alkaline solution, or an aqueous solution. The Group VIB metal is selected from W and / or Mo, and the Group VIII metal is selected from Co and / or Ni. The content of the Group VIB metal oxide in the solution is 1.5-8.5 g / 100 mL, and the content of the Group VIII metal oxide is 0.5-3.5 g / 100 mL.

[0017] The impregnation can be carried out by spray impregnation, saturation impregnation or supersaturation impregnation. The drying condition is to dry at 100-160°C for 1-5 hours; the calcination condition is to calcine at 400-550°C for 2-10 hours.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] The present invention processes an alumina matrix, and after the treatment, curved lamellar alumina grows in the original pores of the carrier, with a high coverage rate of the curved lamellar alumina, and accumulates to form pores of 100-500nm. This technology is a secondary treatment of the hydrogenation protective agent carrier. The carrier before treatment is generally calcined at a relatively high temperature. The high temperature calcination ensures that the carrier has high strength and high macropore content. The treated carrier is calcined at a relatively low temperature, so that the curved lamellar alumina in the pores is converted into a γ phase. Compared with the untreated carrier, the treated carrier maintains the high strength and high macropore content of the original carrier, while the specific surface area and pore content of 100-500nm of the carrier are significantly improved. This pore structure is conducive to the removal of metal impurities such as iron and calcium by the catalyst, and at the same time, the removal rate of nickel, vanadium and sulfur is relatively high. The preparation process of the hydrogenation protective agent is simple, the raw materials are simple and easy to obtain, the equipment investment is small, and it is easy to industrialize. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a low-magnification SEM image of the carrier prepared in Example 1.

[0021] Figure 2 This is a high-magnification SEM image of the carrier prepared in Example 1.

[0022] FIG3 is a low-magnification SEM image of the carrier prepared in Comparative Example 3.

[0023] FIG4 is a high-magnification SEM image of the carrier prepared in Comparative Example 3. DETAILED DESCRIPTION

[0024] The technical solutions and effects of the present invention are further described below with reference to the following embodiments, but are not limited to the following embodiments.

[0025] The pore structure of the samples from the examples and comparative examples was characterized using N2 physical adsorption-desorption. The specific procedure was as follows: The pore structure of the samples was characterized using an ASAP-2420 N2 physical adsorption-desorption instrument. A small amount of sample was vacuum-treated at 300°C for 3-4 hours. Finally, the product was subjected to nitrogen adsorption-desorption testing at a low temperature of liquid nitrogen (-200°C). The specific surface area was calculated using the BET equation, and the pore size distribution and pore volume were calculated using the BJH model.

[0026] Scanning electron microscopy was used to characterize the microstructure of the samples. The specific operation was as follows: a JSM-7500F scanning electron microscope was used to characterize the microstructure of the samples with an accelerating voltage of 5 KV, an accelerating current of 20 μA, and a working distance of 8 mm.

[0027] Mercury intrusion method: A mercury intrusion instrument was used to characterize the pore diameter distribution of the samples in the examples and comparative examples. The specific operation was as follows: The sample pore distribution was characterized using a Micromeritics AutoPore 9500 fully automatic mercury intrusion instrument. After drying, the sample was weighed and placed into a dilatometer. The sample was degassed for 30 minutes while maintaining the vacuum conditions specified by the instrument, and then mercury was added. The dilatometer was then placed in an autoclave and vented. Then, pressure increase and pressure reduction tests were performed. The mercury contact angle was 130°, and the mercury interfacial tension was 0.485 N.cm. -1 The distribution rate of pores with a diameter of 100 nm or more is measured by mercury intrusion method.

[0028] V+Ni removal rate % = (metal V+Ni content of crude oil - metal V+Ni content of product) / metal V+Ni content of crude oil × 100%.

[0029] Ca+Fe removal rate% = (Ca+Fe content of crude oil metal - Ca+Fe content of product metal) / Ca+Fe content of crude oil metal × 100%.

[0030] Desulfurization rate % = (Sulfur content of feedstock oil - Sulfur content of product) / Metal Sulfur content of feedstock oil × 100%.

[0031] The alumina substrate used in this example is a commercial product, spherical in shape, and has a specific surface area of ​​15 m 2 / g, the pore volume is 0.89mL / g, the pore volume of pores larger than 1μm accounts for 26% of the total pore volume, and the pore volume of pores with a pore diameter of 100-500nm accounts for 13% of the total pore volume.

[0032] Example 1

[0033] (1) Weigh 100 g of the above-mentioned alumina substrate and impregnate the substrate with a 40% aluminum nitrate solution for 1 hour. The impregnated substrate is dried at 120°C for 5 hours and calcined at 500°C for 6 hours. After cooling the calcined substrate, the above impregnation, drying, and calcination steps are repeated to obtain a substrate precursor material.

[0034] (2) Weigh 100 g of the above-mentioned carrier precursor material, add 550 g of propylene oxide with a mass concentration of 6.5% and stir for 20 minutes. After stirring, transfer the material into an autoclave, seal it and heat it at 135°C for 6 hours. After treatment, the material is separated by liquid-solid separation, the solid material is dried at 120°C for 4 hours and calcined at 550°C for 5 hours to obtain the hydrogenation protective agent carrier S1. The scanning electron microscope image of the carrier is shown in Figure 1 , the carrier properties are shown in Table 1;

[0035] (3) 50 g of the above-mentioned hydrogenation protective agent carrier was weighed and saturated with a Mo-Ni-P impregnation solution having a molybdenum oxide concentration of 6.3 g / 100 mL and a nickel oxide concentration of 2.6 g / 100 mL. The impregnated material was dried at 120 °C for 3 hours and calcined at 450 °C for 5 hours to obtain the hydrogenation protective agent Cat-1. The catalyst properties are shown in Table 2.

[0036] Example 2

[0037] The same method as in Example 1 was used, except that the mass concentration of the aluminum nitrate solution in step (1) was 35%, and the calcination temperature was 550°C; the amount of propylene oxide used in step (2) was 650 g, and the mass concentration of propylene oxide in the solution was 5.2%. The heat treatment temperature was 145°C, the treatment time was 5 hours, and the calcination temperature was 500°C. Hydrogenation protective agent carrier S2 and hydrogenation protective agent Cat-2 were prepared. The properties of the carrier are shown in Table 1, and the properties of the catalyst are shown in Table 2.

[0038] Example 3

[0039] The same method as in Example 1 was used, except that in step (1), the mass concentration of the aluminum nitrate solution was 30%, the number of aluminum salt solution immersions was three, and the calcination temperature was 450°C. In step (2), the amount of propylene oxide used was 450 g, the mass concentration of propylene oxide in the solution was 7.5%, and 0.4 g of polyethylene glycol-20000 was added to the propylene oxide solution. The heat treatment temperature was 155°C, the treatment time was 4 hours, and the calcination temperature was 450°C. Hydrogenation protective agent carrier S3 and hydrogenation protective agent Cat-3 were prepared. The properties of the carrier are shown in Table 1, and the properties of the catalyst are shown in Table 2.

[0040] Example 4

[0041] The same method as in Example 1 was used, except that the mass concentration of the aluminum nitrate solution in step (1) was 50%; the amount of propylene oxide used in step (2) was 750 g, and the mass concentration of propylene oxide in the solution was 4.4%. The heat treatment temperature was 125°C and the treatment time was 7 hours. Hydrogenation protective agent carrier S4 and hydrogenation protective agent Cat-4 were prepared. The properties of the carrier are shown in Table 1, and the properties of the catalyst are shown in Table 2.

[0042] Comparative Example 1

[0043] The same as Example 1, except that steps (1) and (2) are omitted, and instead the carrier is directly impregnated with the active metal component impregnation solution to prepare comparative hydrogenation protective agent carrier S5 and comparative hydrogenation protective agent Cat-5. The properties of the carrier are shown in Table 1, and the properties of the catalyst are shown in Table 2.

[0044] Comparative Example 2

[0045] The same method as Example 1 was used except that step (2) was omitted to prepare comparative hydrogenation protective agent carrier S6 and comparative hydrogenation protective agent Cat-6. The properties of the carrier are shown in Table 1, and the properties of the catalyst are shown in Table 2.

[0046] Comparative Example 3

[0047] The same method as Example 1 was used, except that the propylene oxide in step (2) was replaced with the same amount of ethylene oxide to prepare comparative hydrogenation protective agent carrier S7 and comparative hydrogenation protective agent Cat-7. The properties of the carrier are shown in Table 1, and the properties of the catalyst are shown in Table 2.

[0048] The SEM images of the carrier are shown in Figure 2 .

[0049] Comparative Example 4

[0050] The same as Example 1, except that the sealing heat treatment temperature in step (2) was 80°C, to prepare comparative hydrogenation protective agent carrier S8 and comparative hydrogenation protective agent Cat-8. The properties of the carriers are shown in Table 1, and the properties of the catalysts are shown in Table 2.

[0051] Comparative Example 5

[0052] The same as Example 1, except that the mass concentration of propylene oxide in step (2) was 1%, to prepare comparative hydrogenation protective agent carrier S9 and comparative hydrogenation protective agent Cat-9. The properties of the carrier are shown in Table 1, and the properties of the catalyst are shown in Table 2.

[0053] Table 1 Properties of hydrogenation protective agent carrier

[0054]

[0055] Table 2 Properties of hydrogenation protective agent

[0056]

[0057] Example 5

[0058] The following examples illustrate the catalytic performance of hydrogenation protected catalysts Cat-1 to Cat-9. The present invention's hydrogenation protected catalysts Cat-1 to Cat-4 and comparative hydrogenation protected catalysts Cat-5 to Cat-9 were loaded into a fixed-bed hydrogenation reactor, respectively. The treated feedstocks (see Table 3) were tested under the following conditions: reaction temperature 385°C, hydrogen-to-oil volume ratio 850, liquid hourly space velocity 0.7 h-1 / 2. -1 , hydrogen partial pressure 14.5MPa, continuous operation 500 hours, impurity removal properties are shown in Table 4.

[0059]

[0060] Table 4 Catalyst evaluation results

[0061]

[0062] From the results in Table 4, it can be seen that the hydrogenation protective agent prepared by the method of the present invention has comparable calcium and iron removal rates, while having higher nickel removal, vanadium removal and desulfurization rates than the comparative hydrogenation protective agent.

Claims

1. An alumina carrier, characterized in that: The alumina carrier comprises an alumina substrate and curved lamellar alumina grown on the substrate surface, wherein the curved lamellar alumina has a length of 0.1-0.8 μm and a thickness of 10-20 nm; the curved lamellar alumina is accumulated to form pores of 100-500 nm, and the coverage of the curved lamellar alumina on the surface of the alumina skeleton is 90%-100%; the content of the curved lamellar alumina is 5%-15% based on the weight of the carrier; the preparation method of the alumina carrier comprises the following steps: (1) impregnating the alumina substrate with an aluminum salt solution, and then drying and baking the aluminum substrate; (2) immersing the material calcined in step (1) in a sealed hydrothermal treatment in a propylene oxide aqueous solution, and drying and calcining the treated material to obtain an alumina carrier; the concentration of the propylene oxide aqueous solution in step (2) is 2.5wt%-12wt%, and the mass ratio of the propylene oxide aqueous solution to the material calcined in step (1) is 3:1-10:1; the sealed hydrothermal treatment in step (2) is carried out in a sealed container, the treatment temperature is 110-180℃, the treatment time is 4-8 hours, and the pressure in the sealed container during the hydrothermal treatment is autogenous pressure.

2. The alumina carrier according to claim 1, characterized in that: The alumina matrix is ​​gamma-alumina, and the shape is spherical, columnar, Raschig ring, impeller ring or honeycomb cylinder.

3. A method for preparing the alumina carrier according to claim 1 or 2, characterized in that The invention comprises the following contents: (1) impregnating an alumina substrate with an aluminum salt solution, and then drying and calcining the substrate; (2) immersing the material calcined in step (1) in a sealed hydrothermal treatment in a propylene oxide aqueous solution, and drying and calcining the treated material to obtain an alumina carrier; the concentration of the propylene oxide aqueous solution in step (2) is 2.5 wt%-12 wt%, and the mass ratio of the propylene oxide aqueous solution to the material calcined in step (1) is 3:1-10:1; the sealed hydrothermal treatment in step (2) is carried out in a sealed container, the treatment temperature is 110-180° C., the treatment time is 4-8 hours, and the pressure in the sealed container during the hydrothermal treatment is autogenous pressure.

4. The method according to claim 3, wherein: The aluminum salt solution in step (1) is an aluminum nitrate aqueous solution, the concentration of aluminum nitrate is 10wt%-60wt%, the amount of aluminum salt solution is such that the alumina substrate is completely immersed, and the immersion time is 0.5-2 hours.

5. The method according to claim 4, characterized in that: The impregnation can be performed once or multiple times. When multiple times are used, drying and roasting are required after each impregnation. The drying temperature is 100-160° C., the drying time is 2-10 hours, and the roasting temperature is 450-550° C., and the roasting time is 4-10 hours.

6. The method according to claim 3, wherein: Polyethylene glycol 2000-20000 is added to the propylene oxide aqueous solution at the same time, and the mass ratio of the added amount of polyethylene glycol 2000-20000 to the carrier precursor material is 0.01:1-0.05:

1.

7. The method according to claim 3, wherein: The drying temperature of step (2) is 100-160°C, and the drying time is 2-10 hours; the roasting temperature is 450-550°C, and the roasting time is 4-10 hours.

8. A hydrogenation protective agent, characterized in that: The hydrogenation protective agent comprises the alumina carrier according to any one of claims 1 to 3; the specific surface area of ​​the hydrogenation protective agent is 40-120 m 2 / g, the pore volume is 0.5-1.0mL / g, the pore volume of pores with a pore diameter greater than 1μm accounts for 10%-30% of the total pore volume, and the pore volume of pores with a pore diameter of 100-500nm accounts for 25%-55% of the total pore volume; based on the weight of the catalyst, the content of the Group VIB metal component in terms of oxide is 3.5%-8%, and the content of the Group VIII metal component in terms of oxide is 0.5%-5.0%; the Group VIB metal component is W and / or Mo; and the Group VIII metal component is Co and / or Ni.

9. A method for preparing the hydrogenation protective agent according to claim 8, characterized in that The method comprises the following steps: impregnating the alumina carrier according to any one of claims 1 to 3 with a hydrogenation active component solution, and drying and calcining the impregnated carrier to obtain a hydrogenation protective agent.

10. The method according to claim 9, characterized in that: The hydrogenation active component solution is a solution containing Group VIB and Group VIII metals, the Group VIB metal is selected from W and / or Mo, and the Group VIII metal is selected from Co and / or Ni; the content of Group VIB metal oxide in the solution is 1.5-8.5 g / 100 mL, and the content of Group VIII metal oxide is 0.5-3.5 g / 100 mL.

11. The method according to claim 9, wherein: The drying condition is to dry at a temperature of 100-160° C. for 1-5 hours; and the roasting condition is to roast at a temperature of 400-550° C. for 2-10 hours.

12. Use of the alumina carrier according to claim 1 or 2 in heavy oil hydroprocessing.

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