A silicon scavenger with high silicon capacity and preparation method thereof

Abstract

A silicon scavenger with high silicon capacity, comprising graphene and alumina, wherein the content of alumina is 5-35wt% and the rest is graphene; the alumina is distributed on the surface of the graphene; the specific surface area of ​​the silicon scavenger is 400-1000m 2 / g, and the surface hydroxyl content is 600-1000µmol / g. A co-precipitation reaction is carried out by adding an aluminum source solution and a precipitant solution to an aqueous solution containing graphene and an organic auxiliary agent, and then mixing them evenly with a peptizing agent and an extrusion aid to form a strip, and drying them in an inert atmosphere to obtain a silicon capture agent. The present invention introduces graphene with a large specific surface area, and adds an organic auxiliary agent during the preparation process to improve the hydrophilicity of the graphene, which is conducive to the precipitation of aluminum oxide on the graphene surface, increases the hydroxyl content on the graphene surface, exposes more Al-OH on the surface, and has an ultra-large specific surface area, which can accommodate more silicides to be deposited on the catalyst surface, thereby improving the utilization rate and life of the silicon capture agent.

Description

Technical Field

[0001] The present invention relates to the technical field of oil hydrogenation, and in particular to a silicon scavenger with high silicon capacity and a preparation method 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 coking product processing, leading to permanent catalyst deactivation. Therefore, the hydroprocessing of coker dry gas, coker naphtha, and coker diesel requires the installation of silicon-capturing catalysts.

[0003] CN200810119343.4 discloses a hydrogenation desiliconization catalyst comprising a boron-containing alumina carrier and a hydrogenation active metal component supported on the carrier, wherein the pore volume of the boron-containing alumina carrier is 0.7 ml / g to 1.1 ml / g, and the specific surface area is 300 m 2 / g~400 m 2 / g, the pore volume of pores with diameters of 4nm to 10nm is 0.60ml / g to 0.77ml / g, and the boron oxide content is 0.5wt% to 50wt% based on the boron-containing alumina carrier. The catalyst is prepared by a method comprising preparing a boron-containing alumina carrier with high pore volume, large specific surface area, and concentrated pore distribution, and then introducing a hydrogenation-active metal component into the carrier.

[0004] CN201711029445.2 discloses a coking naphtha desiliconization catalyst, comprising a carrier and a main active metal, wherein the main active metal is loaded on the carrier, wherein Ni and Mo are the main active metals and Al2O3-TiO2-La2O3 graphene composite oxide is used as the carrier; the catalyst has a specific surface area of ​​250 to 500 m 2 / g, pore volume 0.5-0.8mL / g. The preparation method of the coking naphtha desiliconization catalyst comprises the following steps: (1) adding a titanium-containing compound, a lanthanum-containing compound, and graphene to alumina powder, mixing them evenly, adding an extrusion aid and a binder, mixing them evenly again, extruding into strips, freeze-drying, and calcining to obtain a carrier; (2) using a compound containing a main active metal to prepare an impregnation solution, impregnating the obtained carrier with an equal volume, freeze-drying, and calcining to obtain a coking naphtha desiliconization catalyst.

[0005] The silicon-capturing catalyst of the above-mentioned invention patent is prepared by impregnating active metal into alumina or modified alumina carrier. Although alumina or modified alumina carrier has a large specific surface area, high-temperature calcination of alumina or modified alumina carrier will cause a loss of specific surface area, thereby reducing the silicon-holding capacity of the silicon-capturing catalyst. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the present invention starts from the silicon capture mechanism of the silicon capture catalyst and prepares a silicon capture agent with high silicon holding capacity by increasing the specific surface area and surface hydroxyl content of the silicon capture catalyst.

[0007] 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 experimental results were normalized according to the catalyst mass. The specific surface area of ​​the silicon scavenger was analyzed using N2-adsorption / desorption. The N2-adsorption / desorption test conditions were as follows: the catalyst was loaded into a sample tube and N2 adsorption and desorption tests were performed at 77K using the ASAP 2420 nitrogen physical adsorption instrument from MICROMERITICS, USA. The Al2O3 content in the silicon scavenger was analyzed using XRF fluorescence spectroscopy. The XRF test conditions were as follows: a ZSX fluorescence spectrometer from Rigaku, Japan, with an output voltage of 20-60KV and an output current of 2-150Ma.

[0008] In order to achieve the above technical objectives, the technical solutions of the present invention are as follows:

[0009] The technical purpose of the first aspect of the present invention is to provide a silicon scavenger with high silicon capacity, comprising graphene and aluminum oxide, wherein the content of the aluminum oxide is 5-35wt%, preferably 5-20wt%, and most preferably 8-15wt%, based on the total weight of the silicon scavenger, and the rest is graphene; the aluminum oxide is distributed on the surface of the graphene; the specific surface area of ​​the silicon scavenger is 400-1000m 2 / g, preferably 550-800m 2 / g, and the surface hydroxyl content is 600-1000µmol / g, preferably 800-1000µmol / g.

[0010] The technical purpose of the second aspect of the present invention is to provide a method for preparing the above-mentioned silicon capture catalyst, comprising the following steps:

[0011] (1) adding an aluminum source solution and a precipitant solution concurrently to an aqueous solution containing graphene and an organic additive to carry out a precipitation reaction, and after the reaction is completed, aging, washing, and drying are performed to obtain a precursor;

[0012] (2) The precursor obtained in step (1) is mixed evenly with a peptizing agent and an extrusion aid, and the mixture is extruded into strips, which are then dried in an inert atmosphere to obtain a silicon scavenger.

[0013] Furthermore, the aluminum source in step (1) is an acidic aluminum salt or an alkaline aluminum salt, the acidic aluminum salt is selected from one or more of Al2(SO4)3, AlCl3 or Al(NO3)3, and the alkaline aluminum salt is NaAlO2; when the acidic aluminum salt is used, the precipitant is selected from one or more of NaOH, NH4OH and NaAlO2; when the alkaline aluminum salt is used, the precipitant is CO2; wherein, the aluminum source solution has an aluminum oxide content of 0.5 g / mL-2 g / mL, and the concentration of the precipitant solution is 0.5 g / mL-5 g / mL.

[0014] Furthermore, the graphene in step (1) is one or two of single-layer graphene, double-layer graphene, few-layer graphene, or multi-layer graphene. The graphene has a particle size of 10-1000 nm, preferably 20-500 nm, and most preferably 30-100 nm.

[0015] The graphene preparation method is well known to those skilled in the art. In a specific embodiment, the graphene is prepared by ultrasonically exfoliating graphite oxide in water for 0.5-3 hours to prepare a graphene oxide suspension, and then adding hydrazine hydrate and / or sodium borohydride to reduce the graphene oxide to graphene.

[0016] Furthermore, the organic auxiliary agent in step (1) is an alcohol or organic acid having 2 to 5 carbon atoms and containing hydroxyl and / or carboxyl groups. Specifically, it is at least one selected from ethanol, propanol, ethylene glycol, glycerol, butanediol, pentanediol, acetic acid, malonic acid, succinic acid, and glutaric acid. The amount of the organic auxiliary agent added is 3 to 20 wt%, preferably 8 to 15 wt%, of the graphene.

[0017] Furthermore, the precipitation reaction conditions in step (1) are: pH 7.5-11, temperature 50-95° C., and time 30-120 min.

[0018] Furthermore, the aging conditions in step (1) are: temperature of 50-90°C, pH value of 7.5-11, and time of 3-24 hours.

[0019] Furthermore, the drying conditions in step (1) are as follows: drying temperature 90-300°C, drying time 2-12 hours.

[0020] Furthermore, the extrusion aid in step (2) 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, sesbania powder and polyethylene glycol.

[0021] Furthermore, the peptizing agent in step (2) 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.

[0022] Furthermore, the inert atmosphere in step (2) is one or more of N2 and an inert gas; and the drying conditions in step (2) are: a drying temperature of 90-500°C and a drying time of 3-10 hours.

[0023] The technical purpose of the third aspect of the present invention is to provide the application of the silicon scavenger, which is used in the hydroprocessing process of silicon-containing oil products.

[0024] Furthermore, the silicon scavenger does not contain active components with hydrogenation activity. To prevent carbon deposition, the silicon scavenger is used in conjunction with other catalysts with hydrogenation activity. In actual hydrogenation processes, silicon scavengers are generally not used alone but are used in combination with catalysts with higher hydrogenation activity.

[0025] Compared with the prior art, the catalyst of the present invention has the following advantages:

[0026] Existing silicon scavengers typically use aluminum oxide as their primary component. However, due to the limited specific surface area of ​​aluminum oxide, their silicon-binding capacity is limited. Therefore, the present invention introduces graphene, which has a large specific surface area. The graphene is first mixed with an organic additive, which adsorbs onto the graphene surface. This not only increases the graphene's hydrophilicity, facilitating the precipitation of aluminum oxide onto the surface, but also increases the hydroxyl content on the graphene surface. The aluminum oxide is then co-precipitated onto the graphene surface. The resulting silicon scavenger has an exceptionally large specific surface area and exposes more Al-OH groups. This facilitates the deposition of more silicides on the catalyst surface during oil hydrogenation, allowing it to accommodate more captured silicon, thereby improving the utilization rate and lifespan of the silicon scavenger.

[0027] Other features and advantages of the present invention will be described in detail in the following detailed description. DETAILED DESCRIPTION

[0028] 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.

[0029] 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 -1All infrared experimental results were normalized according to the catalyst mass.

[0030] The present invention uses N2-adsorption / desorption to analyze the specific surface area of ​​the silicon capture agent. 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.

[0031] The present invention adopts XRF fluorescence spectrum to analyze the Al2O3 content in the silicon trapping agent. The XRF test conditions are: using a ZSX fluorescence spectrum analyzer from Japan Rigaku Company, an output voltage of 20-60KV, and an output current of 2-150Ma.

[0032] Example 1

[0033] (1) Graphene oxide was added to deionized water and stirred evenly, and ultrasonicated for 1 hour to prepare a graphene oxide suspension. Then, sodium borohydride was added to reduce the graphene oxide to graphene. The graphene oxide was filtered, washed, dried, and ground to obtain graphene with a particle size of 20-50 nm. Graphene was mixed evenly with glycerol and deionized water, wherein the weight ratio of graphene: glycerol: deionized water was 95:5:1000 to obtain a graphene mixture. Then, aluminum sulfate solution (wherein the aluminum oxide content was 0.9 g / mL) and sodium metaaluminate solution (wherein the aluminum oxide content was 0.9 g / mL) were added to the graphene mixture in parallel, and the temperature was controlled at 70°C and the pH value was 8.5. A coprecipitation reaction occurred for 30 minutes, and the mixture was aged at 70°C and pH value 8.5 for 4 hours. After filtering, washing, and drying at 110°C for 3 hours, the precursor was obtained.

[0034] (2) The precursor prepared in step (1) was mixed evenly with sesbania powder, nitric acid, and deionized water, wherein the weight ratio of the precursor: sesbania powder: nitric acid: deionized water was 95:3:3.5:90. After extrusion, the mixture was dried at 300°C in a N2 atmosphere for 5 hours to obtain a silicon scavenger FS-1.

[0035] The weight percentages of the components in the silicon scavenger FS-1 are as follows: Al2O3 is 5.3%, and the rest is graphene.

[0036] Example 2

[0037] (1) Graphene oxide was added to deionized water and stirred evenly, and ultrasonicated for 2 hours to prepare a graphene oxide suspension. Then, sodium borohydride was added to reduce the graphene oxide to graphene. The graphene oxide was filtered, washed, dried, and ground to obtain graphene with a particle size of 50-70 nm. Graphene was mixed evenly with ethanol and deionized water, wherein the weight ratio of graphene: ethanol: deionized water was 91:9:1000, to obtain a graphene mixture. Then, aluminum sulfate solution (wherein the aluminum oxide content was 1.0 g / mL) and sodium metaaluminate solution (wherein the aluminum oxide content was 1.0 g / mL) were added to the graphene mixture in parallel, and the temperature was controlled at 75°C and the pH value was 8.0. A coprecipitation reaction occurred for 40 minutes, and then the mixture was aged at 80°C and pH value 8.5 for 5 hours. After filtering, washing, and drying at 90°C for 3 hours, the precursor was obtained.

[0038] (2) The precursor prepared in step (1) was mixed evenly with sesbania powder, nitric acid, and deionized water, wherein the weight ratio of the precursor: sesbania powder: nitric acid: deionized water was 95:3:3.5:90. After extrusion, the mixture was dried at 350°C in a N2 atmosphere for 5 hours to obtain a silicon scavenger FS-2.

[0039] The weight percentages of the components in the silicon scavenger FS-2 are as follows: Al2O3 is 8.9% and the rest is graphene.

[0040] Example 3

[0041] (1) Graphene oxide was added to deionized water and stirred evenly, and ultrasonicated for 2 hours to prepare a graphene oxide suspension. Then, sodium borohydride was added to reduce the graphene oxide to graphene. The graphene oxide was filtered, washed, dried, and ground to obtain graphene with a particle size of 70-80 nm. Graphene was mixed evenly with acetic acid and deionized water, wherein the weight ratio of graphene: acetic acid: deionized water was 88:12:1000 to obtain a graphene mixture. Then, aluminum sulfate solution (wherein the aluminum oxide content was 0.9 g / mL) and sodium metaaluminate solution (wherein the aluminum oxide content was 1.0 g / mL) were added to the graphene mixture in parallel, and the temperature was controlled at 80°C and the pH value was 8.8. A coprecipitation reaction occurred for 50 minutes, and then the mixture was aged at 80°C and pH value 8.8 for 4 hours. After filtering, washing, and drying at 120°C for 3 hours, the precursor was obtained.

[0042] (2) The precursor prepared in step (1) was mixed evenly with starch, nitric acid, and deionized water, wherein the weight ratio of the precursor: starch: nitric acid: deionized water was 95:3:3.5:90. After extrusion, the mixture was dried at 300° C. in a N2 atmosphere for 5 hours to obtain a silicon scavenger FS-3.

[0043] The weight percentages of the components in the silicon scavenger FS-3 are as follows: Al2O3 is 10.3% and the rest is graphene.

[0044] Example 4

[0045] (1) Graphene oxide was added to deionized water and stirred evenly, and ultrasonicated for 2 hours to prepare a graphene oxide suspension. Then, sodium borohydride was added to reduce the graphene oxide to graphene. The graphene oxide was filtered, washed, dried, and ground to obtain graphene with a particle size of 50-70 nm. Graphene was mixed evenly with succinic acid and deionized water, wherein the weight ratio of graphene:succinic acid:deionized water was 85:15:1000 to obtain a graphene mixture. Then, aluminum sulfate solution (wherein the aluminum oxide content was 0.9 g / mL) and sodium metaaluminate solution (wherein the aluminum oxide content was 1.0 g / mL) were added to the graphene mixture in parallel, and the temperature was controlled to 80°C and the pH value was 8.8. A coprecipitation reaction occurred for 50 minutes, and the mixture was aged at 80°C and pH value of 8.8 for 4 hours. After filtering, washing, and drying at 120°C for 3 hours, the precursor was obtained.

[0046] (2) The precursor prepared in step (1) was mixed evenly with sesbania powder, phosphoric acid, and deionized water, wherein the weight ratio of the precursor: sesbania powder: phosphoric acid: deionized water was 95:3:3.5:90. After extrusion, the mixture was dried at 350°C in a nitrogen atmosphere for 5 hours to obtain a silicon scavenger FS-4.

[0047] The weight percentages of the components in the silicon scavenger FS-4 are as follows: Al2O3 is 14.2%, and the rest is graphene.

[0048] Example 5

[0049] (1) Graphene oxide was added to deionized water and stirred evenly, and ultrasonicated for 2 hours to prepare a graphene oxide suspension. Then, sodium borohydride was added to reduce the graphene oxide to graphene. The graphene oxide was filtered, washed, dried, and ground to obtain graphene with a particle size of 550-600 nm. The graphene was then mixed evenly with succinic acid and deionized water, wherein the weight ratio of graphene:succinic acid:deionized water was 85:15:1000 to obtain a graphene mixture. Then, aluminum sulfate solution (wherein the aluminum oxide content was 0.9 g / mL) and sodium metaaluminate solution (wherein the aluminum oxide content was 1.0 g / mL) were added to the graphene mixture in parallel, and the temperature was controlled to 80°C and the pH value was 8.0. A coprecipitation reaction occurred for 60 minutes, and then the mixture was aged at 80°C and pH value 8.0 for 4 hours. After filtering, washing, and drying at 100°C for 3 hours, the precursor was obtained.

[0050] (2) The precursor prepared in step (1) was mixed evenly with sesbania powder, phosphoric acid, and deionized water, wherein the weight ratio of the precursor: sesbania powder: phosphoric acid: deionized water was 95:3:6:90. After extrusion, the mixture was dried at 400°C in a nitrogen atmosphere for 5 hours to obtain a silicon scavenger FS-5.

[0051] The weight percentages of the components in the silicon scavenger FS-5 are as follows: Al2O3 is 16.3%, and the rest is graphene.

[0052] Example 6

[0053] (1) Graphene oxide was added to deionized water and stirred evenly, and ultrasonicated for 2 hours to prepare a graphene oxide suspension. Then, sodium borohydride was added to reduce the graphene oxide to graphene. The graphene oxide was filtered, washed, dried, and ground to obtain graphene with a particle size of 550-600 nm. The graphene was then mixed evenly with pentanediol and deionized water, wherein the weight ratio of graphene: pentanediol: deionized water was 85:15:1000 to obtain a graphene mixture. Then, aluminum sulfate solution (wherein the aluminum oxide content was 1.5 g / mL) and sodium metaaluminate solution (wherein the aluminum oxide content was 1.2 g / mL) were added to the graphene mixture in parallel, and the temperature was controlled to 85°C and the pH value was 8.5. A coprecipitation reaction occurred for 60 minutes, and then the mixture was aged at 85°C and pH value 8.5 for 4 hours. After filtering, washing, and drying at 100°C for 3 hours, the precursor was obtained.

[0054] (2) The precursor prepared in step (1) was mixed evenly with sesbania powder, nitric acid, and deionized water, wherein the weight ratio of the precursor: sesbania powder: nitric acid: deionized water was 95:3:6:90. After extrusion, the mixture was dried at 400°C in a N2 atmosphere for 5 hours to obtain a silicon scavenger FS-6.

[0055] The weight percentages of the components in the silicon scavenger FS-6 are as follows: Al2O3 is 32.6%, and the rest is graphene.

[0056] Comparative Example 1

[0057] In step (1), acetic acid was not added, and the other steps were the same as those in Example 3. In step (2), the operation process was the same as that in Example 3 to obtain a comparative silicon trapping agent DC-1.

[0058] The weight percentages of the components in the comparative silicon capture agent DC-1 are as follows: Al2O3 is 10.3%, and the rest is graphene.

[0059] Comparative Example 2

[0060] In step (1), the particle size of graphene is 2-5 μm, and the other steps are the same as those in Example 3. The operation process of step (2) is the same as that in Example 3, and a comparative silicon trapping agent DC-2 is obtained.

[0061] The weight percentages of the components in the comparative silicon capture agent DC-2 are as follows: Al2O3 is 10.3%, and the rest is graphene.

[0062] Comparative Example 3

[0063] (1) Aluminum sulfate solution (with an aluminum oxide content of 0.9 g / mL) and sodium metaaluminate solution (with an aluminum oxide content of 1.0 g / mL) were added to deionized water in parallel, and the temperature was controlled at 80°C and the pH value was 8.8. A coprecipitation reaction occurred for 50 minutes, and then the mixture was aged at 80°C and pH value 8.8 for 4 hours. After filtration and washing, the precursor was dried at 120°C for 3 hours.

[0064] The operation process of step (2) is the same as that of Example 3 to obtain a comparative silicon capture agent DC-3.

[0065] The weight percentages of the components in the comparative silicon capture agent DC-3 are: Al2O3 is 100%.

[0066] Comparative Example 4

[0067] (1) Graphene oxide was added to deionized water, stirred evenly, and ultrasonicated for 2 h to prepare a graphene oxide suspension. Then, sodium borohydride was added to reduce the graphene oxide to graphene. The graphene was filtered, washed, dried, and ground to obtain graphene particles with a particle size of 70-80 nm.

[0068] Aluminum sulfate solution (with an aluminum oxide content of 0.9 g / mL) and sodium metaaluminate solution (with an aluminum oxide content of 1.0 g / mL) were added to deionized water in parallel, and the temperature was controlled at 80°C and the pH value was 8.8. Neutralization was completed after 50 minutes, and then aged at 80°C and pH 8.8 for 4 hours. After filtering, washing, and drying at 120°C for 3 hours, an aluminum oxide precursor was obtained.

[0069] (2) The graphene and alumina precursor prepared in step (1) were uniformly mixed with acetic acid, starch, nitric acid, and deionized water, wherein the weight ratio of graphene: alumina precursor: acetic acid: starch: nitric acid: deionized water was 90:20:12.3:3:3.5:90. After extrusion, the mixture was dried at 300°C in a N2 atmosphere for 5 hours to obtain a comparative silicon scavenger DC-4.

[0070] The weight percentages of the components in the comparative silicon capture agent DC-4 are as follows: Al2O3 is 10.3%, and the rest is graphene.

[0071] The physicochemical properties of the silicon scavengers FS-1 to FS-6 prepared in the above examples and the silicon scavengers DC-1 to DC-4 prepared in the comparative examples were analyzed. The analysis results are shown in Table 1.

[0072] Table 1.

[0073]

[0074] Example 7

[0075] This example illustrates the silicon capture activity of the catalyst provided by the present invention for coker naphtha.

[0076] The raw oil used for evaluation was coking naphtha provided by a refinery of Sinopec. Its main properties are as follows: sulfur content of 2356μg / g, nitrogen content of 64μg / g, and silicon content of 124μg / g. A 200mL fixed-bed hydrogenation unit was used to evaluate the silicon capture capacity of the silicon capture catalysts FS-1 to FS-6 and the comparative examples DC-1 to DC-4. The evaluation reaction conditions were: operating pressure of 3.0MPa, reaction temperature of 320℃, hydrogen / oil volume ratio of 200:1, and volume space velocity of 4.0h -1 After running for 300 hours, the silicon scavenger was unloaded and then calcined at 500℃ in a nitrogen atmosphere for 3 hours. The SiO2 content in the silicon scavenger was analyzed by XRF. The evaluation results are shown in Table 2.

[0077] Table 2.

[0078]

[0079] As can be seen from Table 2, the silicon scavenger of the present invention has a very high silicon holding capacity.

Claims

1. A silicon scavenger with high silicon capacity, characterized in that: The silicon scavenger comprises graphene and aluminum oxide, wherein the aluminum oxide content is 5-35wt% based on the total weight of the silicon scavenger, and the rest is graphene; the aluminum oxide is distributed on the surface of the graphene; the specific surface area of ​​the silicon scavenger is 400-1000m 2 / g, surface hydroxyl content is 600-1000µmol / g; The silicon scavenger is prepared by the following steps: (1) adding an aluminum source solution and a precipitant solution concurrently to an aqueous solution containing graphene and an organic additive, wherein the organic additive is an alcohol and / or an organic acid having 2 to 5 carbon atoms, to carry out a precipitation reaction, and after the reaction is completed, aging, washing, and drying are performed to obtain a precursor; (2) The precursor obtained in step (1) is mixed evenly with a peptizing agent and an extrusion aid, and the mixture is extruded into strips, which are then dried in an inert atmosphere to obtain a silicon scavenger.

2. The silicon scavenger according to claim 1, characterized in that Based on the total weight of the silicon scavenger, the content of the aluminum oxide is 5-20wt%.

3. The silicon scavenger according to claim 2, characterized in that Based on the total weight of the silicon scavenger, the content of the aluminum oxide is 8-15wt%.

4. The silicon scavenger according to claim 1, characterized in that Specific surface area is 550-800m 2 / g.

5. The silicon scavenger according to claim 1, characterized in that The surface hydroxyl content is 800-1000µmol / g.

6. The method for preparing the silicon scavenger according to claim 1, comprising the following steps: (1) adding an aluminum source solution and a precipitant solution concurrently to an aqueous solution containing graphene and an organic additive, wherein the organic additive is an alcohol and / or an organic acid having 2 to 5 carbon atoms, to carry out a precipitation reaction, and after the reaction is completed, aging, washing, and drying are performed to obtain a precursor; (2) The precursor obtained in step (1) is mixed evenly with a peptizing agent and an extrusion aid, and the mixture is extruded into strips, which are then dried in an inert atmosphere to obtain a silicon scavenger.

7. The preparation method according to claim 6, characterized in that The aluminum source in step (1) is an acidic aluminum salt or an alkaline aluminum salt, wherein the acidic aluminum salt is selected from one or more of Al2(SO4)3, AlCl3 or Al(NO3)3, and the alkaline aluminum salt is NaAlO2.

8. The preparation method according to claim 7, characterized in that When acidic aluminum salt is used, the precipitant is selected from one or more of NaOH, NH4OH and NaAlO2; when basic aluminum salt is used, the precipitant is CO2.

9. The preparation method according to claim 6, characterized in that The aluminum source solution has an aluminum oxide content of 0.5 g / mL to 2 g / mL.

10. The preparation method according to claim 6, characterized in that The particle size of the graphene is 10-1000 nm.

11. The preparation method according to claim 10, characterized in that: The particle size of the graphene is 20-500 nm.

12. The preparation method according to claim 11, characterized in that The particle size of the graphene is 30-100 nm.

13. The preparation method according to claim 6, characterized in that The organic auxiliary agent is selected from at least one of ethanol, propanol, ethylene glycol, glycerol, butanediol, pentanediol, acetic acid, malonic acid, succinic acid and glutaric acid.

14. The preparation method according to claim 6, characterized in that The amount of the organic auxiliary agent added is 3-20 wt % of the graphene.

15. The preparation method according to claim 6, characterized in that The precipitation reaction conditions of step (1) are as follows: pH value 7.5-11, temperature 50-95°C, and time 30-120 min.

16. The preparation method according to claim 6, characterized in that The aging conditions in step (1) are: temperature of 50-90° C., pH value of 7.5-11, and time of 3-24 hours.

17. Use of the silicon scavenger according to claim 1 in a hydroprocessing process of silicon-containing oil products.

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