A silicon capture catalyst, its preparation method and application

Abstract

The present invention provides a silicon-capturing catalyst, which is prepared as follows: an aluminum oxide precursor is uniformly mixed with an active metal salt or metal oxide, and an extrusion aid, a peptizing agent and water are then added and mixed, the mixture is extruded into strips, and then dried and sulfurized to obtain a catalyst precursor. An aluminum source and a precipitant are added to the precursor concurrently, a precipitation reaction is carried out, and the catalyst is aged, filtered, washed, and dried to obtain the silicon-capturing catalyst. The method of the present invention first prepares a precursor carrier by a kneading method. The kneading method coats the aluminum oxide precursor with the metal salt or metal oxide. Compared to the impregnation method, this method can prevent more aluminum oxide from being covered, thereby increasing the exposure of the aluminum oxide to the external surface and increasing the surface hydroxyl content. Pseudoboehmite is then loaded on the surface of the precursor to further increase the surface hydroxyl content of the catalyst.

Description

Technical Field

[0001] The present invention relates to the technical field of oil hydrogenation, and in particular to a silicon-capturing catalyst and a preparation method and application thereof. Background Art

[0002] Currently, my country still has a large number of delayed coking units processing heavy, low-quality oil. Defoamers are used during this process, resulting in a certain amount of silicon in products such as coker dry gas, coker naphtha, and coker diesel. This silicon poisons the catalysts used in subsequent processing of the coker products, leading to permanent deactivation. Therefore, the hydroprocessing of coker dry gas, coker naphtha, and coker diesel requires the installation of silicon-capturing catalysts. Silicides are typically deposited on the catalyst surface by interacting with Al-OH groups. Therefore, increasing the catalyst's surface hydroxyl content can effectively increase both the catalyst's silicon capture capacity and its ability to capture silicon.

[0003] CN201811322068.6 discloses a distillate oil hydroprocessing catalyst and its preparation method. Based on the weight of the catalyst, the weight content of the hydrogenation active metal in the form of sulfide is 14% to 50%, the average platelet length of MoS2 is 4 to 7 nm, the average number of platelets in a single stack is 1 to 4 layers, and the proportion of stacks with 3 to 5 layers is 40% to 90%. The preparation method is as follows: (1) preparing an impregnation solution containing the hydrogenation active metal, an organic additive, sodium methylenebisnaphthalenesulfonate, and an aluminum salt; (2) mixing, kneading, shaping, drying, and calcining macroporous alumina powder and the impregnation solution to obtain an oxidized hydrogenation catalyst; (3) subjecting the oxidized catalyst to a sulfidation treatment to obtain a catalyst. Although the preparation method of the invention can be applied to the development of silicon capture catalysts, the surface hydroxyl content of the prepared silicon capture catalyst is limited, which will affect the silicon capture capacity and silicon holding capacity of the silicon capture catalyst.

[0004] CN201410809089.6 The present invention discloses a coking gasoline desiliconization catalyst and its preparation method. The catalyst uses an Al2O3-TiO2-B2O3 composite oxide as a carrier and Ni-Mo-W-Ce as an active component. The Al2O3-TiO2-B2O3 carrier contains 10-20% TiO2 by weight, 3-10% B2O3 by weight, and the remainder is Al2O3. The active components, by weight, include 1.2-3.9% NiO, 4.2-9.5% MoO3, 5-15% WO3, and 1.5-2.5% CeO2, with the remainder being the carrier. The catalyst is calcined in a steam atmosphere, exhibiting a specific pore size and large pore volume, effectively adsorbing and removing impure silicon, protecting the subsequent coking gasoline main hydrorefining catalyst. The silicon capture catalyst of this invention patent adopts a preparation method of impregnating active metal into a modified alumina carrier. The active metal will cover part of the alumina surface, resulting in a decrease in the number of surface hydroxyl groups, leading to a decrease in the silicon capture amount and silicon capture capacity. Summary of the Invention

[0005] In view of the deficiencies of the prior art, the present invention provides a silicon-capturing catalyst, which improves the silicon-capturing ability of the catalyst as a whole by increasing the specific surface area and the surface hydroxyl content of the silicon-capturing catalyst.

[0006] In the context of this specification, FTIR (infrared spectroscopy) was used to analyze the hydroxyl content of the catalyst. The FTIR test conditions included grinding the catalyst, pressing it into a 13 mm diameter self-supporting sheet, and placing it on the in-situ cell sample holder. The experiment used a Nicolet 6700 Fourier transform infrared spectrometer with 32 scans, a resolution of 4 cm-1, and a range of 4000 to 650 cm-1. -1 Measurements were made using an MCT / A detector. All infrared results were normalized according to catalyst mass. The specific surface area of ​​the silicon capture catalyst was analyzed using N adsorption / desorption. The N adsorption / desorption test conditions were as follows: the catalyst was loaded into a sample tube and N adsorption and desorption were performed using an ASAP 2420 nitrogen physical adsorption instrument (MICROMERITICS, USA) at 77K.

[0007] In order to achieve the above technical objectives, the technical solutions of the present invention are as follows:

[0008] The technical purpose of the first aspect of the present invention is to provide a method for preparing a silicon capture catalyst, comprising the following steps:

[0009] (1) Alumina precursor is mixed with Group VIB metal salt or / and Group VIB metal oxide, Group VIII metal salt or / and Group VIII metal oxide, and an extrusion aid, and then a peptizer and water are added to mix evenly, extruded into strips, and then dried and sulfurized to obtain a catalyst precursor;

[0010] (2) Adding the aluminum source and the precipitant concurrently to the catalyst precursor of step (1), performing precipitation reaction, aging, filtering, washing, and drying to obtain the silicon-capturing catalyst.

[0011] Furthermore, the particle size of the aluminum oxide precursor is 1-500 nm, preferably 5-200 nm; the particle size of the Group VIB metal salt or / and Group VIB metal oxide, the Group VIII metal salt or / and Group VIII metal oxide is 1-100 µm, preferably 5-80 µm.

[0012] Furthermore, the uniform mixing in step (1) is to mix the raw materials by any solid material mixing means available in the prior art to achieve a degree of sufficient mixing recognized by those skilled in the art.

[0013] Furthermore, the precursor of the aluminum oxide in step (1) is selected from one or more of pseudo-boehmite, boehmite, gibbsite, nordstromite and diaspore.

[0014] Furthermore, the Group VIB metal salt in step (1) is a phosphate and / or an ammonium salt.

[0015] Furthermore, the Group VIII metal salt in step (1) is selected from one or more of nitrates, carbonates, phosphates, sulfates, basic carbonates and acetates.

[0016] Furthermore, the Group VIB metal is molybdenum and / or tungsten, and the Group VIII metal is nickel and / or cobalt.

[0017] Furthermore, the extrusion aid in step (1) is well known to those skilled in the art. As a more specific embodiment, the extrusion aid is selected from at least one of starch, polyethylene glycol and sesbania powder.

[0018] Furthermore, the peptizing agent in step (1) is well known to those skilled in the art. As a more specific embodiment, the peptizing agent is selected from at least one of nitric acid, phosphoric acid and acetic acid.

[0019] Furthermore, the aluminum oxide precursor is calculated as aluminum oxide, and the amount of the extrusion aid added is 2-8 wt %, preferably 3-5 wt %, of the aluminum oxide.

[0020] Furthermore, the aluminum oxide precursor is calculated as aluminum oxide, and the amount of the peptizing agent added is 1-8 wt %, preferably 2-5 wt % of the aluminum oxide; the amount of water added is 50-150 wt %, preferably 80-120 wt % of the aluminum oxide.

[0021] Furthermore, the drying conditions in step (1) are: drying temperature 90-300° C., and drying time 3-6 hours.

[0022] Furthermore, the vulcanization treatment in step (1) is dry vulcanization or wet vulcanization. The vulcanizing agent for dry vulcanization is hydrogen sulfide, and the vulcanizing agent for wet vulcanization is selected from one or two of carbon disulfide, dimethyl disulfide, methyl sulfide, and n-butyl sulfide; the vulcanization pressure is 2.0-6.4 MPa, the vulcanization temperature is 250-400°C, and the vulcanization time is 4-12 hours.

[0023] Furthermore, the aluminum source in step (2) is an acidic aluminum salt or an alkaline aluminum salt. When an acidic aluminum salt is used, the precipitant is selected from one or more of NaOH, NH4OH and NaAlO2; when an alkaline aluminum salt is used, the precipitant is CO2; wherein the acidic aluminum salt is selected from one or more of Al2(SO4)3, AlCl3 and Al(NO3)3, and the alkaline aluminum salt is NaAlO2; wherein the concentration of the aluminum source, calculated as alumina content, is 0.5 g / mL-10 g / mL, preferably 0.5 g / mL-2 g / mL, and the concentration of the precipitant is 0.5 g / mL-10 g / mL, preferably 0.5 g / mL-5 g / mL.

[0024] Furthermore, the conditions of the precipitation reaction in step (2) are: pH value 7.5-11, temperature 50-95° C., and time 30-120 min.

[0025] Furthermore, the aging conditions in step (2) are: temperature of 50-90° C., pH value of 7.5-11, and time of 3-24 hours.

[0026] Furthermore, the drying conditions in step (2) are as follows: drying temperature 90-300°C, drying time 2-12 hours.

[0027] Furthermore, all steps after the sulfurization treatment in step (1) are carried out under an inert atmosphere, wherein the inert atmosphere is one or more of N2 and an inert gas.

[0028] The technical purpose of the second aspect of the present invention is to provide a silicon-capturing catalyst prepared by the above-mentioned preparation method. The method of the present invention first prepares a precursor carrier by a kneading method. The kneading method allows the precursor of aluminum oxide to be coated with a metal salt or a metal oxide. Compared with the impregnation method, it can avoid more aluminum oxide from being covered, thereby increasing the chance of aluminum oxide being exposed on the outer surface and increasing the surface hydroxyl content. After that, pseudo-boehmite is loaded on the surface of the precursor to further increase the surface hydroxyl content of the catalyst. The silicon-capturing catalyst prepared by the present invention has a specific surface area of ​​300-400m 2 / g, and the surface hydroxyl content is 1000-2200µmol / g, preferably 1500-2000µmol / g.

[0029] The technical purpose of the third aspect of the present invention is to provide an application of the silicon-capturing catalyst, which is used in the hydroprocessing process of silicon-containing oil products.

[0030] Furthermore, the silicon-capturing catalyst does not need to be sulfurized before use.

[0031] Compared with the prior art, the silicon capture catalyst of the present invention has the following advantages:

[0032] (1) The silicon-capturing catalyst of the present invention is loaded with pseudo-boehmite components on its surface, which provides abundant surface hydroxyl groups for the silicon-capturing catalyst, thereby improving its silicon-holding capacity.

[0033] (2) In the process of preparing the silicon-capturing catalyst of the present invention, the precursor carrier is first prepared by a kneading method. The kneading method wraps the aluminum oxide precursor with the metal salt or metal oxide. Compared with the impregnation method, it can avoid more aluminum oxide from being covered. As a more preferred technical solution, an aluminum oxide precursor with a relatively smaller particle size and a metal salt or metal oxide with a relatively larger particle size can be selected. This makes it easier to form a particle form in which the active metal salt or oxide is wrapped by the aluminum oxide precursor, blocking the contact between some aluminum oxide particles, thereby greatly increasing the specific surface area of ​​the catalyst, and more aluminum oxide surface is exposed to the outside, thereby increasing the chance of aluminum oxide being exposed on the outer surface and increasing the surface hydroxyl content.

[0034] (3) In the process of preparing the silicon-capturing catalyst of the present invention, the catalyst is first sulfided and then loaded with pseudo-boehmite. In this way, the pseudo-boehmite is loaded on the VIB group metal sulfide, the VIII group metal sulfide and the carrier alumina, which can increase the contact area between the pseudo-boehmite and the VIII group metal and the VIB group metal, improve the synergistic effect of the hydrogenation performance and silicon-capturing performance of the catalyst, and improve the silicon-holding capacity of the silicon-capturing catalyst. At the same time, it can also reduce the carbon deposition of the catalyst and prevent the carbon deposition from occupying the silicon-capturing active sites.

[0035] (4) In the process of preparing the silicon-capturing catalyst of the present invention, the pseudo-boehmite is loaded and then dried without a calcination process, which prevents the aggregation of the pseudo-boehmite particles from causing a decrease in the surface hydroxyl content, thereby further improving the silicon-capturing capacity of the silicon-capturing catalyst.

[0036] Other features and advantages of the present invention will be described in detail in the following detailed description. DETAILED DESCRIPTION

[0037] The following non-limiting examples may enable those skilled in the art to more fully understand the present invention, but are not intended to limit the present invention in any way.

[0038] The present invention uses FTIR (infrared spectroscopy) to analyze the hydroxyl content of the catalyst. The FTIR test conditions include: after the catalyst is ground, pressed into a Φ13mm self-supporting sheet, and placed on the in-situ cell sample holder. The experiment uses a Nicolet 6700 Fourier transform infrared spectrometer with 32 scans and a resolution of 4cm. -1 , 4000~650cm -1 All infrared experimental results were normalized according to the catalyst mass.

[0039] The present invention uses N2-adsorption / desorption to analyze the specific surface area of ​​the silicon capture catalyst. The N2-adsorption / desorption test conditions are as follows: the catalyst is loaded into a sample tube, and the ASAP 2420 nitrogen physical adsorption instrument from MICROMERITICS, USA, is used to perform N2 adsorption and desorption tests at a temperature of 77K.

[0040] In the following examples and comparative examples, the contents of metal sulfide and alumina are calculated by the feed amount, and the content of pseudo-boehmite is calculated by the weight difference between the catalyst precursor and the finally prepared silicon scavenger.

[0041] Example 1

[0042] (1) Grind molybdenum oxide and nickel oxide to a particle size of 10-20µm, and mix them evenly with pseudo-boehmite and sesbania powder with a particle size of 5-10nm, where the pseudo-boehmite is calculated as alumina, and the weight ratio of each component is m(molybdenum oxide):m(nickel oxide):m(alumina):m(sesbania powder) =9.3:2.6:88.1:3.6. Then, nitric acid and water are evenly added, where the amount of nitric acid added is 4.2% of the alumina and the amount of water added is 90% of the alumina. After mixing evenly, extrude and mold, and then dry at 140°C for 4 hours. Then, sulfurize with hydrogen containing 1.5% H2S at a sulfurization temperature of 360°C, a sulfurization pressure of 4.2MPa, and a sulfurization time of 6h. Then, cool to room temperature in a N2 atmosphere to obtain a catalyst precursor.

[0043] (2) Aluminum sulfate solution (wherein the aluminum oxide content is 1.9 g / mL) and sodium metaaluminate solution (wherein the aluminum oxide content is 1.9 g / mL) are added in parallel to the catalyst precursor prepared in step (1), and the temperature is controlled to 80°C and the pH value is 8.5. A coprecipitation reaction occurs for 50 minutes, and aging is continued at 80°C and pH value 8.5 for 3 hours. After filtering and washing, the silicon capture catalyst FS-1 is obtained at 100°C in a nitrogen atmosphere for 5 hours.

[0044] The weight percentages of the components in the silicon capture catalyst FS-1 are: MoS2 is 8.4%, NiS is 2.3%, alumina is 80.1%, and pseudo-boehmite is 9.2%.

[0045] Example 2

[0046] (1) Grind ammonium heptamolybdate and basic cobalt carbonate to a particle size of 10-20µm, and mix them evenly with pseudo-boehmite and sesbania powder with a particle size of 5-10nm. The active metal is calculated as oxide, and the pseudo-boehmite is calculated as alumina. The weight ratio of each component is m(molybdenum oxide):m(cobalt oxide):m(alumina):m(sesbania powder) = 8.9:3.1:88:4.2. Phosphoric acid and water are evenly added, wherein the amount of phosphoric acid added is 4.5% of alumina and the amount of water added is 95% of alumina. After mixing evenly, extrude and mold, and then dry at 150℃ for 5 hours. Then, sulfurize with hydrogen containing 1.5% H2S at a sulfurization temperature of 350℃, a sulfurization pressure of 4.0MPa, and a sulfurization time of 6h. Then, cool to room temperature in a N2 atmosphere to obtain a catalyst precursor.

[0047] (2) Aluminum sulfate solution (wherein the aluminum oxide content is 0.9 g / mL) and sodium metaaluminate solution (wherein the aluminum oxide content is 0.9 g / mL) are added in parallel to the catalyst precursor prepared in step (1), and the temperature is controlled to 90°C and the pH value is 8.5. A coprecipitation reaction occurs for 60 minutes, and aging is continued at 90°C and pH value 8.5 for 3 hours. After filtering and washing, the silicon capture catalyst FS-2 is obtained by drying at 130°C in a nitrogen atmosphere for 5 hours.

[0048] The weight percentages of the components in the silicon capture catalyst FS-2 are: MoS2 is 8.0%, CoS is 3.1%, alumina is 84.3%, and pseudo-boehmite is 4.6%.

[0049] Example 3

[0050] (1) Grind molybdenum oxide, basic nickel carbonate, and basic cobalt carbonate to a particle size of 20-30 μm, and mix them evenly with pseudo-boehmite and sesbania powder with a particle size of 50-80 nm. The active metal is calculated as oxide, and the pseudo-boehmite is calculated as alumina. The weight ratio of each component is m (molybdenum oxide): m (nickel oxide): m (cobalt oxide): m (alumina): m (sesbania powder) = 9.3:1.2:2.1:87.4:4. Then, nitric acid and water are evenly added, wherein the amount of nitric acid added is 3.5% of the alumina and the amount of water added is 95% of the alumina. After mixing evenly, extrude and mold, and then treat at 130 ° C for 5 hours. Then, sulfurize with hydrogen containing 1.5% H2S at a sulfurization temperature of 340 ° C, a sulfurization pressure of 4.5 MPa, and a sulfurization time of 5 hours. Then, cool to room temperature in a N2 atmosphere to obtain a catalyst precursor.

[0051] (2) Aluminum sulfate solution (wherein the aluminum oxide content is 1.2 g / mL) and sodium metaaluminate solution (wherein the aluminum oxide content is 1.2 g / mL) are added in parallel to the catalyst precursor prepared in step (1), and the temperature is controlled to be 90°C and the pH value is 8.5. A coprecipitation reaction occurs for 60 minutes, and aging is continued at 90°C and pH value 8.5 for 3 hours. After filtering and washing, the silicon capture catalyst FS-3 is obtained by drying at 1230°C in a nitrogen atmosphere for 5 hours.

[0052] The weight percentages of the components in the silicon capture catalyst FS-3 are: MoS2 is 8.4%, NiS is 1.1%, CoS is 2.1%, alumina is 82.8%, and pseudo-boehmite is 5.7%.

[0053] Example 4

[0054] (1) Ammonium tungstate and nickel sulfide are ground to a particle size of 20-30µm, and mixed evenly with boehmite and sesbania powder with a particle size of 5-10nm. The active metal is calculated as oxide, and the boehmite is calculated as alumina. The weight ratio of each component is m(molybdenum oxide):m(nickel oxide):m(alumina):m(sesbania powder) = 12.1:3.6:84.3:4. Then phosphoric acid and water are evenly added, wherein the amount of phosphoric acid added is 4.5% of alumina and the amount of water added is 95% of alumina. After mixing evenly, the mixture is extruded and then dried at 150°C for 3 hours. Then, the mixture is sulfurized with hydrogen containing 2.5% H2S at a sulfurization temperature of 350°C, a sulfurization pressure of 4.0MPa, and a sulfurization time of 6h. Then, the mixture is cooled to room temperature in a N2 atmosphere to obtain a catalyst precursor.

[0055] (2) Aluminum sulfate solution (wherein the aluminum oxide content is 1.6 g / mL) and sodium metaaluminate solution (wherein the aluminum oxide content is 1.6 g / mL) are added in parallel to the catalyst precursor prepared in step (1), and the temperature is controlled to 90°C and the pH value is 8.5. A coprecipitation reaction occurs for 50 minutes, and aging is continued at 90°C and pH value 8.5 for 3 hours. After filtering and washing, the silicon capture catalyst FS-4 is obtained by drying at 130°C in a nitrogen atmosphere for 5 hours.

[0056] The weight percentages of the components in the silicon capture catalyst FS-4 are: WS2 is 10.9%, NiS is 3.2%, alumina is 79.6%, and pseudo-boehmite is 6.3%.

[0057] Example 5

[0058] (1) Grind ammonium tungstate and basic cobalt carbonate to a particle size of 10-30µm, and mix them evenly with boehmite and sesbania powder with a particle size of 5-10nm. The active metal is calculated as oxide, and the boehmite is calculated as alumina. The weight ratio of each component is m(molybdenum oxide):m(cobalt oxide):m(alumina):m(sesbania powder) = 10.7:2.8:86.5:4. Then, phosphoric acid and water are evenly added, wherein the amount of phosphoric acid added is 3.5% of the alumina and the amount of water added is 95% of the alumina. After mixing evenly, extrude and mold, and then dry at 130℃ for 5 hours. Then, sulfurize with hydrogen containing 1.5% H2S at a sulfurization temperature of 340℃, a sulfurization pressure of 4.6MPa, and a sulfurization time of 6h. Then, cool to room temperature in a N2 atmosphere to obtain a catalyst precursor.

[0059] (2) Aluminum sulfate solution (wherein the aluminum oxide content is 1.8 g / mL) and sodium metaaluminate solution (wherein the aluminum oxide content is 1.8 g / mL) are added in parallel to the catalyst precursor prepared in step (1), and the temperature is controlled to 80°C and the pH value is 8.5. A coprecipitation reaction occurs for 60 minutes, and aging is continued at 80°C and pH value 8.5 for 3 hours. After filtering and washing, the silicon capture catalyst FS-5 is obtained by drying at 130°C in a nitrogen atmosphere for 5 hours.

[0060] The weight percentages of the components in the silicon capture catalyst FS-5 are: WS2 is 9.6%, CoS is 2.8%, alumina is 80.7%, and pseudo-boehmite is 6.9%.

[0061] Example 6

[0062] (1) Grind tungsten oxide, nickel oxide, and basic cobalt carbonate to a particle size of 50-100 μm, and mix them evenly with pseudo-boehmite and sesbania powder with a particle size of 5-10 nm. The active metal is calculated as oxide, and the pseudo-boehmite is calculated as alumina. The weight ratio of each component is m(tungsten oxide):m(nickel oxide):m(cobalt oxide):m(alumina):m(sesbania powder) = 12.3:2.1:2.6:83:4. Then, phosphoric acid and water are evenly added, wherein the amount of phosphoric acid added is 3.5% of the alumina and the amount of water added is 95% of the alumina. After mixing evenly, extrude and mold, and then treat at 150°C for 3 hours. Then, sulfurize with hydrogen containing 1.5% H2S at a sulfurization temperature of 350°C, a sulfurization pressure of 4.0 MPa, and a sulfurization time of 6 hours. Then, cool to room temperature in a N2 atmosphere to obtain a catalyst precursor.

[0063] (2) Aluminum sulfate solution (wherein the aluminum oxide content is 1.9 g / mL) and sodium metaaluminate solution (wherein the aluminum oxide content is 1.9 g / mL) are added in parallel to the catalyst precursor prepared in step (1), and the temperature is controlled to be 90°C and the pH value is 8.5. A coprecipitation reaction occurs for 50 minutes, and aging is continued at 90°C and pH value 8.5 for 3 hours. After filtering and washing, the silicon capture catalyst FS-6 is obtained by drying at 130°C in a nitrogen atmosphere for 5 hours.

[0064] The weight percentages of the components in the silicon capture catalyst FS-6 are: WS2 is 11.1%, NiS is 1.9%, CoS is 2.6%, alumina is 76.2%, and pseudo-boehmite is 8.2%.

[0065] Example 7

[0066] (1) Ammonium molybdate, ammonium tungstate, and basic nickel carbonate were ground to a particle size of 10-20 μm, and then mixed evenly with pseudo-boehmite and sesbania powder with a particle size of 5-10 nm. The active metal was calculated as oxide, and the pseudo-boehmite was calculated as alumina. The weight ratio of each component was m(molybdenum oxide):m(tungsten oxide):m(nickel oxide):m(alumina):m(sesbania powder) = 6.1:5.9:2.3:85.7:4. Phosphoric acid and water were then added evenly, wherein the amount of phosphoric acid added was 3.5% of the alumina and the amount of water added was 115% of the alumina. After mixing evenly, the mixture was extruded and then dried at 140°C for 3 hours. The mixture was then sulfurized with hydrogen containing 2.5% H2S at a temperature of 320°C, a pressure of 4.8 MPa, and a time of 6 hours. The mixture was then cooled to room temperature in a N2 atmosphere to obtain a catalyst precursor.

[0067] (2) Aluminum sulfate solution (wherein the aluminum oxide content is 2.1 g / mL) and sodium metaaluminate solution (wherein the aluminum oxide content is 2.1 g / mL) are added in parallel to the catalyst precursor prepared in step (1), and the temperature is controlled to be 90°C and the pH value is 8.5. A coprecipitation reaction occurs for 40 minutes, and aging is continued at 90°C and pH value 8.5 for 3 hours. After filtering and washing, the silicon capture catalyst FS-7 is obtained by drying at 130°C in a nitrogen atmosphere for 5 hours.

[0068] The weight percentages of the components in the silicon capture catalyst FS-7 are: MoS2 is 5.5%, WS2 is 5.3%, NiS is 2.1%, alumina is 80.7%, and pseudo-boehmite is 6.4%.

[0069] Comparative Example 1

[0070] Step (1) dissolving ammonium heptamolybdate and nickel nitrate in water to form a metal salt solution, and then uniformly mixing the solution with pseudo-boehmite and sesbania powder having a particle size of 5-10 nm, wherein the active metal is calculated as oxide and the pseudo-boehmite is calculated as aluminum oxide, wherein the weight ratio of the components is m (molybdenum oxide): m (nickel oxide): m (aluminum oxide): m (sesbania powder) = 9.3:2.6:88.1:3. The other steps are the same as in Example 1 to obtain a catalyst precursor.

[0071] The operation process of step (2) is the same as that of Example 1 to obtain a comparative silicon capture catalyst DC-1.

[0072] The weight percentages of the components in the comparative silicon capture catalyst DC-1 are as follows: MoS2 is 8.4%, NiS is 2.3%, alumina is 80.1%, and pseudo-boehmite is 9.2%.

[0073] Comparative Example 2

[0074] Step (1) Pseudoboehmite, nitric acid, starch, and deionized water are uniformly mixed, wherein the mass ratio of pseudoboehmite: nitric acid: starch: deionized water is 100:3.5:3:90, and then kneaded and extruded into strips, followed by drying at 120°C for 5 hours and calcining at 700°C for 3 hours to obtain an alumina support. Ammonium heptamolybdate and nickel nitrate solutions are impregnated into the alumina support prepared in step (1). The other steps are the same as in Example 1 to obtain a catalyst precursor.

[0075] The operation process of step (2) is the same as that of Example 1 to obtain a comparative silicon capture catalyst DC-2.

[0076] The weight percentages of the components in the comparative silicon capture catalyst DC-2 are as follows: MoS2 is 8.4%, NiS is 2.3%, alumina is 80.1%, and pseudo-boehmite is 9.2%.

[0077] Comparative Example 3

[0078] Step (1) is the same as in Example 1, except that no sulfurization process is performed, to obtain a catalyst precursor.

[0079] Step (2) is to load the pseudo-boehmite and then perform a sulfidation treatment. The other steps are the same as those in Example 1 to obtain a comparative silicon capture catalyst DC-3.

[0080] The weight percentages of the components in the comparative silicon capture catalyst DC-3 are as follows: MoS2 is 8.4%, NiS is 2.3%, alumina is 80.1%, and pseudo-boehmite is 9.2%.

[0081] Comparative Example 4

[0082] Step (1) grinding molybdenum oxide and nickel oxide to a particle size of 10-20 μm, and uniformly mixing them with pseudo-boehmite and sesbania powder having a particle size of 800-900 nm, wherein the active metal is calculated as oxide and the pseudo-boehmite is calculated as aluminum oxide, wherein the weight ratio of each component is m(molybdenum oxide):m(nickel oxide):m(aluminum oxide):m(sesbania powder) = 9.3:2.6:88.1:3, and the other steps are the same as in Example 1, to obtain a catalyst precursor;

[0083] The operation process of step (2) is the same as that of Example 1, and a comparative silicon capture catalyst DC-4 is obtained.

[0084] The weight percentages of the components in the comparative silicon capture catalyst DC-4 are as follows: MoS2 is 8.4%, NiS is 2.3%, alumina is 80.1%, and pseudo-boehmite is 9.2%.

[0085] Comparative Example 5

[0086] Step (1) Grind molybdenum oxide and nickel oxide to a particle size of 10-20 μm, and mix them evenly with pseudo-boehmite and sesbania powder with a particle size of 5-10 nm, nitric acid, and deionized water. The active metal is calculated as oxide, and the pseudo-boehmite is calculated as aluminum oxide. The weight ratio of each component is m(molybdenum oxide):m(nickel oxide):m(aluminum oxide):m(sesbania powder):m(nitric acid):m(water)=9.3:2.6:88.1:3:3:90. Extrusion molding is performed. The other steps are the same as in Example 1 to obtain a catalyst precursor.

[0087] Step (2) was the same as in Example 1 to obtain a comparative silicon capture catalyst DC-5.

[0088] The weight percentages of the components in the comparative silicon capture catalyst DC-5 are as follows: MoS2 is 8.4%, NiS is 2.3%, alumina is 80.1%, and pseudo-boehmite is 9.2%.

[0089] Comparative Example 6

[0090] Step (1) is the same as in Example 1. In step (2), a calcination process is added during the operation, and the calcination conditions are 450° C. for 3 hours in a nitrogen atmosphere. The other steps are the same as in Example 1, and a comparative silicon trapping agent DC-6 is obtained.

[0091] The weight percentages of the components in the comparative silicon capture agent DC-6 are as follows: MoS2 is 8.4%, NiS is 2.3%, alumina is 80.1%, and pseudo-boehmite is 9.2%.

[0092] Comparative Example 7

[0093] Step (1) is the same as in Example 1. Step (2) is omitted, and a comparative silicon trapping agent DC-7 is obtained.

[0094] The weight percentages of the components in the comparative silicon capture agent DC-7 are: MoS2 is 8.4%, NiS is 2.3%, and aluminum oxide is 89.3%.

[0095] The physicochemical properties of the catalysts FS-1 to FS-7 prepared in the above examples and the catalysts DC-1 to DC-7 prepared in the comparative examples were analyzed. The analysis results are shown in Table 1.

[0096] Table 1.

[0097]

[0098] Example 8

[0099] This example illustrates the silicon capture activity of the catalyst provided by the present invention for coking naphtha.

[0100] The raw oil used for evaluation is coking naphtha provided by a refinery of Sinopec, and its main properties are as follows: sulfur content is 3257μg / g, nitrogen content is 74μg / g, and silicon content is 116μg / g. A 200mL fixed bed hydrogenation device was used to evaluate the silicon capture capacity of silicon capture catalysts FS-1 to FS-7 and comparative examples DC-1 to DC-7. Among them, silicon capture catalysts FS-1 to FS-7 and comparative examples DC-1 to DC-7 do not require pre-sulfurization treatment. The evaluation reaction conditions are: operating pressure 3.0MPa, reaction temperature 310℃, hydrogen / oil volume ratio 200:1, volume space velocity is 2.0h -1 After running for 300 hours, the silicon scavenger was unloaded and then calcined at 500℃ for 3 hours. The SiO2 content in the silicon scavenger was analyzed by XRF. The evaluation results are shown in Table 2.

[0101] Table 2.

[0102]

[0103] As can be seen from Table 2, the silicon-capturing catalyst of the present invention has a very high silicon-holding capacity.

Claims

1. A method for preparing a silicon capture catalyst, comprising the following steps: (1) Alumina precursor is mixed with Group VIB metal salt or / and Group VIB metal oxide, Group VIII metal salt or / and Group VIII metal oxide, and an extrusion aid, and then a peptizer and water are added to mix evenly, extruded into strips, and then dried and sulfurized to obtain a catalyst precursor; (2) adding the aluminum source and the precipitant concurrently to the catalyst precursor of step (1), performing a precipitation reaction, aging, filtering, washing, and drying to obtain the silicon capture catalyst; The particle size of the aluminum oxide precursor is 1-500 nm, and the particle size of the Group VIB metal salt or / and Group VIB metal oxide, the Group VIII metal salt or / and Group VIII metal oxide is 1-100 μm. The specific surface area of ​​the prepared silicon capture catalyst is 300-400m 2 / g, and the surface hydroxyl content is 1000-2200µmol / g.

2. The preparation method according to claim 1, characterized in that The precursor of aluminum oxide in step (1) is selected from one or more of pseudo-boehmite, boehmite, gibbsite, nordstromite and diaspore.

3. The preparation method according to claim 1, characterized in that The Group VIB metal salt is a phosphate and / or an ammonium salt, and the Group VIII metal salt in step (1) is selected from one or more of nitrates, carbonates, phosphates, sulfates, basic carbonates and acetates.

4. The preparation method according to claim 1, characterized in that The alumina precursor is calculated as alumina, and the amount of the extrusion aid added is 2-8 wt % of the alumina.

5. The preparation method according to claim 1, characterized in that The aluminum oxide precursor is calculated as aluminum oxide, and the amount of the peptizing agent added is 1-8 wt % of the aluminum oxide.

6. The preparation method according to claim 1, characterized in that The drying conditions in step (1) are: drying temperature 90-300°C, and drying time 3-6 hours.

7. The preparation method according to claim 1, characterized in that The aluminum source in step (2) is an acidic aluminum salt or an alkaline aluminum salt. When an acidic aluminum salt is used, the precipitant is selected from one or more of NaOH, NH4OH and NaAlO2; when an alkaline aluminum salt is used, the precipitant is CO2.

8. The preparation method according to claim 7, characterized in that The acidic aluminum salt is selected from one or more of Al2(SO4)3, AlCl3 and Al(NO3)3, and the basic aluminum salt is NaAlO2.

9. The preparation method according to claim 1, characterized in that The conditions of the precipitation reaction in step (2) are: pH 7.5-11, temperature 50-95° C., and time 30-120 min.

10. The preparation method according to claim 1, characterized in that The aging conditions in step (2) are: temperature of 50-90° C., pH value of 7.5-11, and time of 3-24 hours.

11. The preparation method according to claim 1, characterized in that The drying conditions in step (2) are as follows: drying temperature 90-300°C, and drying time 2-12 hours.

12. The silicon-capturing catalyst prepared by the preparation method according to claim 1.

13. Use of the silicon-trapping catalyst according to claim 12, wherein the catalyst is used in the hydrogenation process of silicon-containing oil products.

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