A residue oil hydrodemetallization catalyst and its preparation method and application

Abstract

The present invention discloses a residue hydrodemetallization catalyst, a preparation method thereof and an application thereof. The catalyst comprises an intermediate coated with a macroporous alumina layer and a second active component supported on the intermediate, and the second active component comprises molybdenum and a Group VIII metal; wherein, in the catalyst, the ratio of the content of tetrahedral molybdenum to the content of octahedral molybdenum is 0.21 to 0.72 in terms of Mo atoms; the pore volume of the macroporous alumina layer is 0.95 to 1.40 cm<supgt;3< / supgt> / g, and the pore volume of pores with a pore diameter of 100 to 400 nm in the pore distribution accounts for more than 25% of the total pore volume. When the catalyst of the present invention is used in the residue hydrodemetallization reaction, both the activity and the stability are significantly improved.

Description

Technical Field

[0001] The present invention relates to a hydrodemetallization catalyst, in particular to a hydrodemetallization catalyst suitable for heavy oil, especially residual oil hydrotreating process, and a preparation method and application thereof. Background Art

[0002] As we all know, the residue hydrodemetallization reaction is one of the important chemical reactions that occur during the residue hydroprocessing process. Under the action of the catalyst, various metal compounds react with H2S to generate metal sulfides, which are then deposited on the catalyst and removed. The presence of active metals on the catalyst carrier will inevitably play an important role in the activity and stability of the catalyst.

[0003] CN1289640A discloses a method for preparing a supported hydrodemetallization catalyst, which uses a macroporous alumina carrier and sprays an ammonia solution or an aqueous solution of an active metal onto the carrier in a spray drum. The method omits the normal temperature drying process of the carrier after impregnation, and directly places the sprayed carrier in a calcination furnace at a temperature of 300-450°C for calcination, then gradually raises the temperature to 460-550°C and keeps the temperature constant for 1-5 hours under air conditions.

[0004] CN103785400A discloses a method for preparing a highly active residue oil hydrodemetallization catalyst, which uses a polyol and / or monosaccharide aqueous solution to impregnate an alumina carrier, performs hydrothermal carbonization in a sealed container after the impregnation, and then loads active metal components Mo and Ni on the carrier, and finally roasts the alumina loaded with active components in a nitrogen atmosphere and then in an air atmosphere to obtain a residue oil hydrodemetallization catalyst. CN102441399A discloses a method for preparing a hydrodemetallization catalyst, which prepares a Group VIB metal compound and / or a Group VIII metal compound into an ammonia solution or aqueous solution, then impregnates the alumina carrier, and obtains the final catalyst by drying and roasting.

[0005] The activity and stability of the hydrodemetallization catalyst prepared by the above method still need to be further improved. Summary of the invention

[0006] In view of the shortcomings of the prior art, the present invention provides a residual oil hydrodemetallization catalyst and its preparation method and application. The catalyst has strong resistance to metal deposition and carbon deposition, and can significantly improve the activity and activity stability when used in residual oil hydrodemetallization reaction.

[0007] The first aspect of the present invention provides a residual oil hydrodemetallization catalyst, comprising an intermediate coated with a macroporous alumina layer and a second active component supported on the intermediate, wherein the second active component comprises molybdenum and a Group VIII metal; wherein, in the catalyst, the ratio of the content of tetrahedral molybdenum to that of octahedral molybdenum, calculated as Mo atoms, is 0.21 to 0.72; the pore volume of the macroporous alumina layer is 0.95 to 1.40 cm 3 / g, and the pore volume with a pore diameter of 100-400 nm in the pore distribution accounts for more than 25% of the total pore volume, preferably 25%-45%.

[0008] In the present invention, the thickness of the macroporous alumina layer is 1 to 200 μm, preferably 20 to 80 μm.

[0009] In the present invention, the intermediate comprises carbon, alumina and a first active component, the first active component comprises molybdenum and a Group VIII metal, wherein the Group VIII metal is preferably nickel.

[0010] In the present invention, the Group VIII metal in the second active component is preferably nickel.

[0011] In the present invention, the catalyst further comprises an auxiliary component, which is selected from at least one of fluorine, phosphorus, silicon or boron, preferably phosphorus. The content of the auxiliary component in terms of oxide is 1.0% to 4.0% based on the mass of the catalyst.

[0012] In the present invention, in the intermediate, the mass ratio of carbon to alumina is 0.05 to 0.35.

[0013] In the present invention, in the catalyst, based on the mass of the catalyst, the content of MoO3 is 5.0% to 15.0%, and the content of the Group VIII metal oxide is 1.0% to 5.0%.

[0014] In the present invention, based on the total MoO3 mass in the catalyst, the content of MoO3 in the first active component is 35.0% to 65.0%, and the content of MoO3 in the second active component is 35.0% to 65.0%.

[0015] In the present invention, based on the total mass of Group VIII metal oxides in the catalyst, the content of Group VIII metal oxides in the first active component is 35.0% to 65.0%, and the content of Group VIII metal oxides in the second active component is 35.0% to 65.0%.

[0016] In the present invention, the specific surface area of ​​the catalyst is 180 to 230 m 2 / g, the pore volume is 0.70~1.20mL / g, and the pore diameter is 16~28nm.

[0017] In the present invention, preferably, the specific surface area of ​​the catalyst is 185 to 210 m 2 / g, the pore volume is 0.85~1.10mL / g, and the pore diameter is 20~25nm.

[0018] The second aspect of the present invention provides a method for preparing the above-mentioned residue hydrodemetallization catalyst, comprising the following steps:

[0019] (1) neutralizing an acidic aluminum salt solution with an alkaline aluminum salt solution to obtain a slurry;

[0020] (2) subjecting the slurry obtained in step (1) to primary aging; after the primary aging, adding a water-soluble polymer J, subjecting the slurry to secondary aging, and drying to obtain a dried product I;

[0021] (3) mixing the dried product I obtained in step (2) with activated carbon in proportion, kneading, molding, and drying to obtain a dried product II;

[0022] (4) spraying the dried product II obtained in step (3) with a first impregnation solution containing a first active component in an unsaturated impregnation manner, drying, and first calcining to obtain a calcined body;

[0023] (5) adding the calcined body obtained in step (4) into macroporous pseudo-boehmite gel, stirring and soaking, taking out and drying after the surface is coated with the gel, and calcining for the second time to obtain an intermediate;

[0024] (6) impregnating the intermediate obtained in step (5) with a second impregnation solution containing a second active component in a saturated impregnation manner, drying, and performing a third calcination to obtain the catalyst.

[0025] In step (1) of the present invention, the acidic aluminum salt solution and the alkaline aluminum salt solution are added to the reaction kettle in a parallel flow.

[0026] In step (1) of the present invention, the acidic aluminum salt solution is one or more of aluminum sulfate solution, aluminum nitrate solution or aluminum chloride solution; the concentration of the acidic aluminum salt solution is 6 g / 100 mL to 26 g / 100 mL in terms of Al2O3. The alkaline aluminum salt solution is one or more of sodium metaaluminate solution and potassium metaaluminate solution; the concentration of the alkaline aluminum salt solution is 10 g / 100 mL to 55 g / 100 mL in terms of Al2O3.

[0027] In step (1) of the present invention, the temperature of the neutralization reaction is 80 to 125° C., the time is 25 to 145 minutes, and the pH value of the slurry is controlled to be 6.0 to 9.5 during the neutralization reaction. The pH value of the slurry is adjusted by controlling the addition rate of the acidic aluminum salt solution and the alkaline aluminum salt solution or by additionally adding an acid-base regulator during the neutralization reaction.

[0028] In step (2) of the present invention, the primary aging temperature is 100 to 230° C., the time is 60 to 220 minutes, and the pH value is 9.0 to 12.0.

[0029] In step (2) of the present invention, the water-soluble polymer J1 is one or more of polyethylene glycol, polyvinyl alcohol, polyacrylamide and methyl cellulose, preferably polyethylene glycol; the viscosity (20°C) of the water-soluble polymer J1 is 10 to 1000 mPa·s, and the viscosity (20°C) of the slurry after adding the water-soluble polymer J1 is 150 to 700 mPa·s.

[0030] In step (2) of the present invention, after the primary aging is completed, preferably, the slurry is first concentrated and then subjected to secondary aging, wherein the volume of the concentrated slurry is 45% to 70% of the original volume.

[0031] In step (2) of the present invention, the secondary aging temperature is 115-270° C., the time is 40-200 minutes, and the secondary aging temperature is 30-60° C. higher than the primary aging temperature.

[0032] In step (2) of the present invention, the drying temperature after secondary aging is 120-180°C, the drying time is 2-10 hours, and filtering and washing can be performed according to conventional known methods before drying. The dry content of the dried product I obtained after drying is 45wt%-70wt%.

[0033] In step (3) of the present invention, the activated carbon is powdered activated carbon. The mesh size of the activated carbon is preferably 150 to 350 meshes.

[0034] In step (3) of the present invention, the mass ratio of activated carbon to dried product I is 1:4-20.

[0035] In step (3) of the present invention, during the molding process, conventional molding aids, such as one or more of sesbania powder, cellulose, and resin, may be added as needed.

[0036] In step (3) of the present invention, the drying temperature is 120 to 200° C. and the drying time is 2 to 12 hours.

[0037] In step (4) of the present invention, in the unsaturated impregnation, the amount of the first impregnation liquid is 10% to 40% of the saturated water absorption of the dried product II.

[0038] In step (4) of the present invention, the first impregnation solution is an impregnation solution containing Mo and a Group VIII metal (preferably Ni), wherein the active metal component molybdenum is derived from one or both of molybdenum oxide and ammonium heptamolybdate, and nickel is derived from one or both of basic nickel carbonate and nickel nitrate, and the contents of MoO3 and Group VIII metal oxide in the first impregnation solution are 30.0-60.0 g / 100 ml and 5.0-30.0 g / 100 ml, respectively. The amount of MoO3 introduced into the catalyst by the first impregnation solution is 35%-65% of the total MoO3 loading in the catalyst; the amount of Group VIII metal oxide introduced into the catalyst by the first impregnation solution is 35%-65% of the total Group VIII metal oxide loading in the catalyst.

[0039] In step (4) of the present invention, at least one auxiliary agent selected from fluorine, phosphorus, silicon or boron may be introduced into the first impregnation solution, and the amount of the auxiliary agent added in terms of oxide is 18% to 28%, preferably 20% to 25%, of the total mass of molybdenum oxide in the first impregnation solution.

[0040] In step (4) of the present invention, preferably, the first impregnation liquid further contains a water-soluble polymer J2. The water-soluble polymer J2 is one or more of polyethylene glycol, polyvinyl alcohol, polyacrylamide and methyl cellulose. The viscosity (20°C) of the water-soluble polymer J2 is 10 to 1000 mPa·s, and the viscosity (20°C) of the slurry after adding the water-soluble polymer J2 is 150 to 700 mPa·s.

[0041] In step (4) of the present invention, the impregnation is carried out by spraying, and the spraying time is 15 to 35 minutes.

[0042] In step (4) of the present invention, the drying temperature is 20 to 200° C. and the drying time is 2 to 12 hours.

[0043] In step (4) of the present invention, the first calcination adopts programmed temperature increase. The heating rate is 1°C / min to 3°C / min, the first calcination temperature is 500 to 750°C, the calcination time is 2 to 6 hours, and the calcination atmosphere is one or both of nitrogen and water vapor, preferably water vapor.

[0044] In step (5) of the present invention, before adding the calcined body to the macroporous pseudo-boehmite gel, the calcined body is preferably soaked in a binder solution. The mass content of the binder in the binder solution is 1% to 45%, preferably 2% to 20%. The binder solution is composed of a binder and pure water. The binder can be one or more of starch, dextrin, polyvinyl alcohol or carboxymethyl cellulose. Preferably, the calcined body is soaked in the binder solution for 10 to 55 seconds, the excess binder solution is drained off, and the body is left at room temperature for 10 to 50 minutes.

[0045] In step (5) of the present invention, the macroporous pseudo-boehmite gel can be obtained by the following method: using an inorganic aluminum source as a raw material, without adding a template, adjusting the pH value to 3.0-3.4, and hydrothermally treating at 180-320° C. for 3.5-6.0 hours. The inorganic aluminum source can be selected from at least one of aluminum sulfate, aluminum nitrate, and aluminum chloride. The concentration of aluminum oxide in the macroporous pseudo-boehmite gel is 10 g / L-80 g / L, and preferably the concentration of aluminum oxide is 15 g / L-45 g / L.

[0046] The macroporous pseudo-boehmite gel described in step (5) of the present invention is converted (calcined at 500-700°C for 2-8 hours, with a heating rate of 1°C / min-4°C / min, and the calcination atmosphere is one or more of air, water vapor, and nitrogen, preferably air) to macroporous alumina, and the properties thereof are as follows: pore volume of 0.95-1.40 cm 3 / g (mercury intrusion method), with open pores at multiple levels from tens of nanometers to hundreds of nanometers to micrometers, in which pores with a pore size of 100 to 400 nm account for more than 25% of the total pore volume, preferably 25% to 45%, which can effectively diffuse macromolecular reactants.

[0047] In step (5) of the present invention, the calcined body is added to the macroporous pseudo-boehmite gel and stirred for 20 seconds to 10 minutes. After the surface is coated with gel, it is taken out, centrifuged to remove excess gel on the surface, and dried at 80 to 150° C. for 2 to 12 hours. The thickness of the aluminum oxide film layer can be controlled by controlling the concentration of aluminum oxide in the macroporous pseudo-boehmite gel, the immersion time and the centrifugation time.

[0048] In step (5) of the present invention, the second calcination adopts programmed temperature rise. The heating rate is 1°C / min to 3°C / min, the second calcination temperature is 450 to 650°C, and the second calcination time is 2 to 6 hours. After the second calcination, an aluminum oxide coating layer of 1 to 200 μm, preferably 20 to 80 μm, can be formed on the surface of the calcined body.

[0049] In step (6) of the present invention, the second impregnation solution contains an impregnation solution of Mo and a Group VIII metal (preferably Ni), wherein the active metal component molybdenum is derived from one or both of molybdenum oxide and ammonium heptamolybdate, and nickel is derived from one or both of basic nickel carbonate and nickel nitrate. The amount of MoO3 introduced into the catalyst by the second impregnation solution is 35% to 65% of the total MoO3 loading in the catalyst; the amount of the Group VIII metal oxide introduced into the catalyst by the second impregnation solution is 35% to 65% of the total Group VIII metal oxide loading in the catalyst.

[0050] In step (6) of the present invention, preferably, the second impregnation liquid further contains a water-soluble polymer J3. The water-soluble polymer J3 is one or more of polyethylene glycol, polyvinyl alcohol, polyacrylamide and methyl cellulose. The viscosity (20°C) of the water-soluble polymer J3 is 10 to 1000 mPa·s, and the viscosity (20°C) of the slurry after adding the water-soluble polymer J3 is 150 to 700 mPa·s.

[0051] In step (6) of the present invention, the impregnation is carried out by spraying, and the spraying time is 15 to 35 minutes.

[0052] In step (6) of the present invention, the drying temperature is 120 to 200° C. and the drying time is 2 to 12 hours.

[0053] In step (6) of the present invention, the third calcination adopts programmed temperature increase. The heating rate is 1°C / min to 3°C / min, the third calcination temperature is 350 to 450°C, the calcination time is 2 to 6 hours, and the calcination atmosphere is one or both of nitrogen and water vapor, preferably water vapor.

[0054] The third aspect of the present invention provides the use of the above-mentioned residue oil hydrodemetallization catalyst in a residue oil hydrotreating process.

[0055] Compared with the prior art, the present invention has the following beneficial effects:

[0056] 1. For hydrogenation catalysts, the reduction temperature of tetrahedral Mo species is greater than that of octahedral Mo species. The presence of tetrahedral Mo has an adverse effect on weakening the interaction between the carrier and the metal, thereby affecting the activity and stability of the catalyst. The inventors have found through extensive research that the carrier is first optimized, the slurry obtained after the neutralization reaction is aged in two stages, a water-soluble polymer is added before the secondary aging, and the secondary aging is performed at a higher temperature, so as to obtain a porous material with a suitable specific surface area and a good pore size distribution, i.e., a dried product I; the dried product I is kneaded and formed with activated carbon in proportion, and dried to obtain a dried product II; then, the dried product II is sprayed with the first impregnation liquid in an unsaturated impregnation manner, and after drying and the first calcination, a calcined body is obtained; the calcined body is added to a macroporous pseudo-boehmite gel, stirred and immersed, and the surface is coated with the gel, taken out and dried, and the second calcination is performed to obtain an intermediate; finally, the second impregnation liquid is impregnated on the intermediate in a saturated impregnation manner, and the catalyst is obtained after drying and the third calcination. After the above treatment process, the distribution ratio of tetrahedral molybdenum and octahedral molybdenum species in the catalyst is more suitable. In addition, water-soluble polymers are added to the two impregnation solutions, which can promote the dispersion of active metals on the one hand, and properly adjust the acidity of the catalyst on the other hand. At the same time, the macroporous alumina layer coated on the surface of the intermediate provides a smooth pore structure for the diffusion of macromolecules, which can prevent the heavy oil macromolecules from blocking the catalyst pores and coking in the early stage of the reaction during the residual oil hydrogenation process, causing the catalyst to coke and deactivate; on the other hand, it provides a suitable loading environment for the dispersion of active metals during the second saturated impregnation process, which is conducive to the uniform dispersion of active metals and provides good preliminary conditions for the reaction of macromolecules on the catalyst surface. In summary, the method of the present invention significantly improves the activity and stability of the residual oil hydrodemetallization catalyst finally obtained through the comprehensive coordination of various steps. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 This is a Raman spectrum of the catalyst surface obtained in Example 1;

[0058] Figure 2 This is a Raman spectrum of the catalyst surface obtained in Example 2;

[0059] Figure 3 This is a Raman spectrum of the catalyst surface obtained in Comparative Example 1;

[0060] Figure 4 This is the Raman spectrum of the catalyst surface obtained in Comparative Example 2. DETAILED DESCRIPTION

[0061] In the present invention, the Raman spectrometer of DXR Microscope type of Thermo Scientific Company is used to characterize the catalyst by Raman spectrum.1 The peak nearby is the peak of tetrahedral molybdenum, at 960cm- 1 The nearby peak is the peak of octahedral molybdenum, and the contents of tetrahedral molybdenum and octahedral molybdenum are calculated based on the area under the same baseline.

[0062] In the present invention, the ASAP-2420 physical adsorption instrument produced by Michael Company is used to characterize the pore structure (SVD) and specific surface area of ​​the catalyst.

[0063] The technical solutions and effects of the present invention are further described below in conjunction with embodiments, but are not limited to the following embodiments.

[0064] Example 1

[0065] 1.5L of aluminum sulfate aqueous solution (with a concentration of 10.0g / 100mL in terms of Al2O3 and an initial temperature of 75°C) was introduced from the top into a reactor equipped with 5L of purified water, a stirrer and a heating jacket, and 1L of sodium aluminate aqueous solution (with a concentration of 28.0g / 100mL in terms of Al2O3 and an initial temperature of 110°C) was introduced from the bottom of the reactor. The neutralization reaction temperature was controlled at 105°C. Aluminum sulfate solution and sodium aluminate solution were added continuously, and the pH value was controlled to be 8.5. The reaction was continued for 60 min. minutes; after the parallel flow is completed, an aging is performed, the aging temperature is 140°C, the aging time is 120 minutes, and the aging pH value is 9.3; after the first aging is completed, the slurry volume is concentrated to 5L, 100g of polyvinyl alcohol (viscosity is 30mPa·s) is added, and the slurry viscosity (20°C) after the addition of polyvinyl alcohol is 260mPa·s, the temperature is raised to 170°C, and a secondary aging is performed, the aging time is 120 minutes, and washing is performed, and drying is performed at 120°C for 6h to obtain a dry matter I with a dry basis of 50wt%;

[0066] The obtained dried product I was kneaded and formed with activated carbon (270 mesh) at a mass ratio of 9.5:0.5, and a conventional molding aid, sesbania powder, was added during the molding process, the amount of which accounted for 2.0% of the solid material before kneading, and then dried at a temperature of 140° C. for 6 hours to obtain a dried product II;

[0067] The dried product II is sprayed with the first impregnation solution (the content of MoO3 is 58.8g / 100ml, the content of NiO is 11.5g / 100ml, and the amount of P (in terms of oxide) in the auxiliary phosphoric acid is 22.8% of the total mass of molybdenum oxide in the impregnation solution) (the amount of the first impregnation solution is 20% of the saturated water absorption of the dried product II), and polyacrylamide (viscosity is 950mPa·s) is added to the first impregnation solution, and the viscosity after addition is 600mPa·s, wherein the amount of MoO3 introduced into the catalyst by the first impregnation solution is 40% of the total MoO3 loading in the catalyst; the amount of NiO introduced into the catalyst by the first impregnation solution is 40% of the total NiO loading in the catalyst, the spraying time is controlled within 30min, and then it is allowed to stand and dry at room temperature of 25°C for 2h, and then the obtained sample is dried at 120°C for 6h, and calcined at 700°C for 5h, wherein the heating rate of the calcination process is 3°C / min, to obtain a calcined body;

[0068] Weigh 200g of the calcined body, soak it in a dextrin solution (the mass content of dextrin is 15%) for 35 seconds, drain off the excess binder solution, and place it at room temperature for 45 minutes, then add it to a macroporous pseudo-boehmite gel (the concentration of alumina is 35g / L) and stir it (the macroporous pseudo-boehmite gel uses aluminum sulfate as a raw material, does not add a template agent, adjusts the pH value to 3.2, and is obtained by hydrothermal treatment at 300°C for 4.5 hours). The soaking time is 8 minutes, and the surface is taken out after the gel is coated, and the excess gel on the surface is removed by centrifugation, dried at 90°C for 10 hours, and calcined at 600°C for 3 hours (the heating rate is 2.0°C / min). After calcination, a 60μm alumina coating layer can be formed on the catalyst surface to obtain an intermediate. The mass ratio of carbon to alumina in the intermediate is 0.32.

[0069] The second impregnation liquid was used to impregnate the intermediate in a saturated impregnation manner, and polyacrylamide (viscosity of 950 mPa·s) was added to the second impregnation liquid, and the viscosity after addition was 400 mPa·s, wherein the amount of MoO3 introduced into the catalyst by the second impregnation liquid was 60% of the total MoO3 loading in the catalyst; the amount of NiO introduced into the catalyst by the second impregnation liquid was 60% of the total NiO loading in the catalyst, the spraying time was controlled within 30 minutes, and then dried at 120°C for 6 hours, and calcined at 350°C for 3 hours, wherein the heating rate of the calcination process was 3°C / min, and the hydrodemetallization catalyst CAT-1 was obtained. The physicochemical properties of the catalyst are shown in Table 1.

[0070] Example 2

[0071] Compared with Example 1, the difference in this example is that the initial temperature of the sodium aluminate aqueous solution added is 100°C, 110g of polyvinyl alcohol (viscosity is 30mPa·s) is added after one aging, and the slurry viscosity (20°C) after the addition of polyvinyl alcohol is 280mPa·s; the obtained dry product I and activated carbon (270 mesh) are kneaded and formed at a mass ratio of 9.0:1.0, and dried to obtain a dry product II; during the molding process, a conventional molding aid, sesbania powder, is added, and the added amount accounts for 4.0% of the solid material before kneading;

[0072] Weigh 200g of the calcined body, soak it in a dextrin solution (the mass content of dextrin is 12%) for 25 seconds, drain off the excess binder solution, and place it at room temperature for 35 minutes, add it into a macroporous pseudo-boehmite gel (the concentration of alumina is 25g / L) and stir it. The soaking time is 6 minutes. After the surface is coated with gel, take it out, use a centrifuge to remove the excess gel on the surface, dry it at 110°C for 8 hours, and calcine it at 650°C for 4 hours (the heating rate is 3.0°C / min). After calcination, a 52μm alumina coating layer can be formed on the catalyst surface to obtain an intermediate. The mass ratio of carbon to alumina in the intermediate is 0.26.

[0073] In the third calcination process, the temperature was raised to 400°C at a heating rate of 3°C / min and calcined for 4h to obtain the hydrodemetallization catalyst CAT-2. The physicochemical properties of the catalyst are shown in Table 1.

[0074] Example 3

[0075] Compared with Example 1, this example is different in that the dried product I and activated carbon (270 mesh) are mixed and kneaded and formed at a mass ratio of 8.5:1.5;

[0076] Weigh 200g of the calcined body, soak it in a starch solution (with a starch content of 8%) for 18 seconds, drain off excess binder solution, and place it at room temperature for 25 minutes, add it into a macroporous pseudo-boehmite gel (with an alumina concentration of 20g / L) and stir it. The soaking time is 5 minutes, take it out after the surface is coated with gel, use a centrifuge to remove excess gel on the surface, dry it at 130°C for 6 hours, and calcine it at 600°C for 3 hours (heating rate is 3.0°C / min). After calcination, a 42μm alumina coating layer can be formed on the catalyst surface to obtain an intermediate. The mass ratio of carbon to alumina in the intermediate is 0.21.

[0077] In the third calcination process, the temperature was raised to 450°C at a heating rate of 3°C / min for 5h to obtain the hydrodemetallization catalyst CAT-3. The physicochemical properties of the catalyst are shown in Table 1.

[0078] Example 4

[0079] Compared with Example 1, the difference in this example is that the dried material I and activated carbon (270 mesh) are kneaded and formed at a mass ratio of 8.0:2.0;

[0080] Weigh 200g of the calcined body, soak it in a starch solution (mass content of starch is 4%) for 12 seconds, drain off the excess binder solution, and place it at room temperature for 15 minutes, add it into a macroporous pseudo-boehmite gel (alumina concentration is 16g / L) and stir it. The soaking time is 2min, take it out after the surface is coated with gel, use a centrifuge to remove the excess gel on the surface, dry it at 150℃ for 4 hours, and calcine it at 550℃ for 2 hours (heating rate is 3.0℃ / min). After calcination, a 36μm alumina coating layer can be formed on the catalyst surface to obtain an intermediate. The mass ratio of carbon to alumina in the intermediate is 0.15.

[0081] In the third calcination process, the temperature was raised to 400°C at a heating rate of 3°C / min and calcined for 6h to obtain the hydrodemetallization catalyst CAT-4. The physicochemical properties of the catalyst are shown in Table 1.

[0082] Example 5

[0083] Compared with Example 1, the difference in this example is that 200 g of the calcined body is weighed, soaked in a starch solution (the mass content of starch is 2%) for 10 seconds, the excess binder solution is drained off, and the body is left at room temperature for 10 minutes, added into a macroporous pseudo-boehmite gel (alumina concentration is 15 g / L) with stirring, the soaking time is 1 min, taken out after the surface is coated with gel, and the excess gel on the surface is removed by centrifuge, dried at 90°C for 10 hours, and calcined at 550°C for 4 hours (heating rate is 2.0°C / min). After calcination, a 25 μm alumina coating layer can be formed on the catalyst surface; the mass ratio of carbon to alumina in the intermediate is 0.08.

[0084] The amount of MoO3 introduced into the catalyst by the first impregnation liquid is 45% of the total MoO3 loading in the catalyst; the amount of the Group VIII metal oxide introduced into the catalyst by the first impregnation liquid is 45% of the total Group VIII metal oxide loading in the catalyst, and the spraying time is controlled within 30 minutes; in the first calcination process, the temperature is raised to 550°C at a heating rate of 3°C / min for 3 hours; in the third calcination process, the temperature is raised to 400°C at a heating rate of 3°C / min for 3 hours to obtain the hydrodemetallization catalyst CAT-5. The physical and chemical properties of the catalyst are shown in Table 1.

[0085] Example 6

[0086] Compared with Example 1, the difference in this example is that after the co-flow is completed, the temperature for the first aging is 160°C, the aging time is 140 minutes, and the aging pH value is 9.5; after the first aging is completed, the slurry volume is concentrated to 5L, and 100g of polyvinyl alcohol (viscosity is 30mPa·s) is added. After adding polyvinyl alcohol, the slurry viscosity (20°C) is 240mPa·s, and the temperature is raised to 200°C for secondary aging, and the aging time is 140 minutes. After calcination, a 62μm alumina coating layer can be formed on the catalyst surface, and an intermediate can be obtained. The mass ratio of carbon to alumina in the intermediate is 0.34; finally, the hydrodemetallization catalyst CAT-6 is obtained. The physicochemical properties of the catalyst are shown in Table 1.

[0087] Comparative Example 1

[0088] The dried material I (same as in Example 1), 2.6 wt% nitric acid and 2.5 wt% sesbania powder were mixed and molded, dried at 140°C for 4 hours, and calcined at 860°C for 4 hours to prepare an alumina carrier; the carrier was directly impregnated with a saturated impregnation solution containing active metals Mo, Ni and P, dried at 140°C for 4 hours, and then calcined at 600°C for 3 hours to prepare a hydrodemetallization catalyst dCAT-1. The physicochemical properties of the catalyst are shown in Table 1.

[0089] Comparative Example 2

[0090] Compared with Example 1, the difference in this example is that the calcined body is not subjected to the stirring treatment process in the macroporous pseudo-boehmite gel, and the hydrodemetallization catalyst dCAT-2 is obtained. The physicochemical properties of the catalyst are shown in Table 1.

[0091] Comparative Example 3

[0092] The active metal solution was directly mixed with the dried product II (same as Example 1), dried at 140°C for 4 hours, and then calcined at 600°C for 3 hours to obtain the hydrodemetallization catalyst dCAT-3. The physicochemical properties of the catalyst are shown in Table 1.

[0093] Table 1 Physicochemical properties of hydrogenation catalysts

[0094]

[0095]

[0096] Evaluation test

[0097] The activity stability test of Examples 1 to 6 and Comparative Examples 1 to 3 was carried out on a 200 ml fixed bed hydrogenation test device. The properties of the feedstock oil are shown in Table 2, the test conditions are shown in Table 3, and the test results are shown in Table 4.

[0098] Table 2 Raw oil properties

[0099] Raw oil properties Middle East Residue S, wt% 2.68 Ni, μg / g 34.3 V, μg / g 62.7

[0100] Table 3 Test conditions

[0101]

[0102]

[0103] Table 4 Test results of various hydrodemetallization catalysts

[0104]

[0105] It can be seen from Table 1 and Table 4 that the hydrodemetallization catalyst prepared by the method of the present invention has a high specific surface area and pore volume, and has high reaction activity and stability, and can well meet the hydrodemetallization process of heavy oil, especially residual oil.

Claims

1. A method for preparing a residual oil hydrodemetallization catalyst, characterized in that: The catalyst comprises an intermediate coated with a macroporous alumina layer and a second active component supported on the intermediate, wherein the second active component comprises molybdenum and a Group VIII metal; the intermediate comprises carbon, alumina and a first active component; wherein, in the catalyst, the ratio of tetrahedral molybdenum to octahedral molybdenum content is 0.21-0.72 based on Mo atoms; the pore volume of the macroporous alumina layer is 0.95-1.40 cm 3 / g, the pore volume with a pore size of 100-400nm in the pore distribution accounts for more than 25% of the total pore volume; the thickness of the macroporous alumina layer is 20-80μm; the specific surface area of ​​the catalyst is 185-210m 2 / g, pore volume of 0.85-1.10mL / g, pore diameter of 20-25nm; the catalyst includes phosphorus as an auxiliary component, and the content of the auxiliary component in terms of oxide is 3.1%-4.0% based on the mass of the catalyst; the preparation method of the catalyst comprises the following steps: (1) neutralizing an acidic aluminum salt solution with an alkaline aluminum salt solution to obtain a slurry; (2) subjecting the slurry obtained in step (1) to primary aging; after the primary aging, adding a water-soluble polymer J, subjecting the slurry to secondary aging, and drying to obtain a dried product I; (3) mixing the dried product I obtained in step (2) with activated carbon in proportion, kneading, molding, and drying to obtain a dried product II; (4) spraying the dried product II obtained in step (3) with a first impregnation solution containing a first active component in an unsaturated impregnation manner, drying, and first calcining to obtain a calcined body; (5) adding the calcined body obtained in step (4) into macroporous pseudo-boehmite gel, stirring and soaking, taking out and drying after the surface is coated with the gel, and calcining for the second time to obtain an intermediate; (6) impregnating the intermediate obtained in step (5) with a second impregnation solution containing a second active component in a saturated impregnation manner, drying, and third calcining to obtain the catalyst; In step (2), the temperature of the primary aging is 100-230°C, the temperature of the secondary aging is 115-270°C, and the temperature of the secondary aging is 30-60°C higher than the temperature of the primary aging; In step (4), the first impregnation solution is introduced with an auxiliary agent phosphorus, and the amount of the auxiliary agent added in terms of oxide is 18% to 28% of the total mass of molybdenum oxide in the first impregnation solution; In step (4), in the unsaturated impregnation, the amount of the first impregnation liquid is 10% to 40% of the saturated water absorption of the dried substance II; In step (4), the first roasting temperature is 500-750°C, and in step (6), the third roasting temperature is 350-450°C.

2. The preparation method according to claim 1, characterized in that: The first active component includes molybdenum and a Group VIII metal.

3. The preparation method according to claim 2, characterized in that: The Group VIII metal in the first active component is nickel.

4. The preparation method according to claim 1 or 2, characterized in that: In the intermediate, the mass ratio of carbon to alumina is 0.05-0.35; based on the total mass of MoO3 in the catalyst, the content of MoO3 in the first active component is 35.0%-65.0%; Based on the total mass of the Group VIII metal oxide in the catalyst, the content of the Group VIII metal oxide in the first active component is 35.0% to 65.0%.

5. The preparation method according to claim 1 or 2, characterized in that: In the catalyst, based on the mass of the catalyst, the content of MoO3 is 5.0% to 15.0%, and the content of the Group VIII metal oxide is 1.0% to 5.0%.

6. The preparation method according to claim 1, characterized in that: In step (1), the acidic aluminum salt solution and the alkaline aluminum salt solution are subjected to a parallel neutralization reaction; the acidic aluminum salt solution is one or more of an aluminum sulfate solution, an aluminum nitrate solution or an aluminum chloride solution; the concentration of the acidic aluminum salt solution in terms of Al2O3 is 6 g / 100 mL to 26 g / 100 mL; the alkaline aluminum salt solution is one or both of a sodium aluminate solution and a potassium aluminate solution; the concentration of the alkaline aluminum salt solution in terms of Al2O3 is 10 g / 100 mL to 55 g / 100 mL; and / or the neutralization reaction temperature is 80 to 125°C, the time is 25 to 145 minutes, and the pH value of the slurry is controlled to be 6.0 to 9.5 during the neutralization reaction.

7. The preparation method according to claim 1, characterized in that: In step (2), the primary aging time is 60 to 220 minutes, and the pH value is 9.0 to 12.

0.

8. The preparation method according to claim 1, characterized in that: In step (2), the water-soluble polymer J is one or more of polyethylene glycol, polyvinyl alcohol, polyacrylamide and methyl cellulose; the viscosity of the water-soluble polymer J at 20°C is 10-1000 mPa·s, and the viscosity of the slurry at 20°C after adding the water-soluble polymer J is 150-700 mPa·s.

9. The preparation method according to claim 1, characterized in that: In step (2), the water-soluble polymer J is polyethylene glycol.

10. The preparation method according to claim 1, characterized in that: In step (2), the secondary aging time is 40 to 200 minutes, the drying temperature after the secondary aging is 120 to 180°C, the drying time is 2 to 10 hours, and the dry basis content of the dried product I obtained after drying is 45 wt% to 70 wt%.

11. The preparation method according to claim 1, characterized in that: In step (3), the mesh size of the activated carbon is 150-350 mesh, the mass ratio of the activated carbon to the dried product I is 1:4-20, the drying temperature is 120-200°C, and the drying time is 2-12 hours.

12. The preparation method according to claim 1, characterized in that: In step (4), the amount of the additive added in terms of oxide is 20% to 25% of the total mass of molybdenum oxide in the first impregnation solution.

13. The preparation method according to claim 1, characterized in that: In step (4), the first roasting time is 2 to 6 hours, and the roasting atmosphere is one or both of nitrogen and water vapor; in step (5), the second roasting temperature is 450 to 650°C, and the second roasting time is 2 to 6 hours; in step (6), the third roasting time is 2 to 6 hours, and the roasting atmosphere is one or both of nitrogen and water vapor.

14. The preparation method according to claim 1, characterized in that: In step (4), the first calcination is carried out in a calcination atmosphere of water vapor; and in step (6), the third calcination is carried out in a calcination atmosphere of water vapor.

15. The preparation method according to claim 1, characterized in that: In step (5), before adding the calcined body into the macroporous pseudo-boehmite gel, the calcined body is immersed in a binder solution for 15 to 55 seconds, and the binder content in the binder solution is 1% to 45%.

16. The preparation method according to claim 15, characterized in that: The mass content of the adhesive in the adhesive solution is 2%~20%.

17. The preparation method according to claim 15, characterized in that: The adhesive is one or more of starch, dextrin, polyvinyl alcohol or carboxymethyl cellulose.

18. The preparation method according to claim 1, characterized in that: In step (5), the concentration of aluminum oxide in the macroporous pseudo-boehmite gel is 10 g / L to 80 g / L; the calcined body is added to the macroporous pseudo-boehmite gel and stirred, and the soaking time is 20 seconds to 10 minutes.

19. The preparation method according to claim 1, characterized in that: In step (5), the concentration of aluminum oxide in the macroporous pseudo-boehmite gel is 15 g / L to 45 g / L.

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