A method for preparing a silicon-capturing catalyst

Abstract

The present invention provides a silicon-capturing catalyst, which is prepared as follows: an impregnation solution containing a Group VIB metal salt and a Group VIII metal salt is impregnated into an alumina carrier, and a catalyst precursor is obtained by drying and sulfurizing the impregnation solution; the catalyst precursor in step (1) is added to an aqueous solution containing a hydroxyl organic compound for hydrothermal treatment; and then the catalyst is dried to obtain a silicon-capturing catalyst. The present invention uses an aqueous solution containing a hydroxyl organic compound to heat-treat the sulfurized catalyst precursor. Firstly, the hydroxyl content on the catalyst surface can be greatly increased, thereby improving the catalyst's silicon-capturing and silicon-accommodating capacity. Secondly, the heat treatment process can modify the micromorphology of the active metal sulfide, increase the active sites, and improve the hydrogenation performance of the catalyst, thereby inhibiting the catalyst from coking and occupying the silicon-capturing active sites. Thirdly, the microstructure of the alumina carrier surface can be modified, thereby generating more grooves on the catalyst surface, increasing the specific surface area of ​​the catalyst, and thus improving the silicon-accommodating capacity.

Description

Technical Field

[0001] The present invention relates to the technical field of oil hydrogenation, and in particular to a silicon-capturing catalyst, and in particular to 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] CN01138515.4 discloses a method for catalytic hydrotreating of silicon-containing naphtha. In the presence of hydrogen and under conditions effective for hydrotreating the feedstock, a hydrocarbon feedstock containing silicon compounds is contacted with a hydrotreating catalyst. The improvement includes the step of adding 0.01-10% by volume of water to the feedstock to moisten the hydrotreating catalyst. While this method can improve the silicon-capturing capacity of the silicon-capturing catalyst, prolonged water addition can significantly impact the catalyst's strength, leading to catalyst collapse and other factors that can cause a pressure drop in the device's bed.

[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 shortcomings of the prior art, the present invention provides a method for preparing a silicon capture catalyst, which uses hydroxyl-containing organic matter to increase the surface hydroxyl content of the silicon capture catalyst and improve the silicon capture ability of the catalyst as a whole.

[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: the catalyst was ground, pressed into a 13 mm diameter self-supporting sheet, and placed on the in-situ cell sample holder. The experiment was performed using a Nicolet 6700 Fourier transform infrared spectrometer with 32 scans and a resolution of 4 cm. -1 , 4000~650cm -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) impregnating an alumina support with an impregnation solution containing a Group VIB metal salt and a Group VIII metal salt, and then drying and sulfurizing the alumina support to obtain a catalyst precursor;

[0010] (2) Adding the catalyst precursor in step (1) to an aqueous solution of a hydroxyl-containing organic compound for hydrothermal treatment; and then drying to obtain a silicon capture catalyst.

[0011] Furthermore, the hydroxyl-containing organic compound is a C2-C10 alcohol, preferably at least one of ethanol, ethylene glycol, glycerol, butanediol and pentanediol.

[0012] Furthermore, in the aqueous solution of the hydroxyl-containing organic compound, the hydroxyl-containing organic compound has a concentration of 0.1 g / mL-10 g / mL, preferably 0.5 g / mL-6.0 g / mL.

[0013] Furthermore, the conditions of the hydrothermal treatment in step (2) are: temperature of 60-200°C, time of 3-10 hours, and pressure of autogenous pressure in a closed container.

[0014] Furthermore, the drying conditions in step (2) are: drying temperature 50-90° C., and drying time 3-6 hours.

[0015] Furthermore, an organic auxiliary agent is preferably added to the impregnation process of step (1), wherein the organic auxiliary agent is a C3-C10 alcohol or an organic acid. Preferably, the organic auxiliary agent is at least one of ethylene glycol, glycerol, butanediol, pentanediol, acetic acid, citric acid, malonic acid, succinic acid, and glutaric acid.

[0016] Furthermore, the Group VIB metal salt in step (1) is a phosphate and / or an ammonium salt.

[0017] Furthermore, the Group VIII metal salt in step (1) is selected from one or more of nitrates, sulfates and acetates.

[0018] Furthermore, the Group VIB metal is molybdenum and / or tungsten, and the Group VIII metal is nickel and / or cobalt.

[0019] Furthermore, the drying conditions in step (1) are: drying temperature 90-300° C., and drying time 3-6 hours.

[0020] 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.

[0021] 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.

[0022] The second aspect of the present invention is to provide a silicon-capturing catalyst prepared by the aforementioned method. This method first prepares the catalyst in a sulfurized state and then heat-treats it with an aqueous solution of a hydroxyl-containing organic compound, significantly increasing the hydroxyl content on the catalyst surface. The organic compound heat treatment also modifies the catalyst's surface micromorphology, increasing the catalyst's specific surface area and thus its silicon-capacity.

[0023] The silicon capture catalyst prepared by the present invention has a specific surface area of ​​300-500m 2 / g, and the surface hydroxyl content is 1000-3000µmol / g, preferably 1500-2500µmol / g.

[0024] 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 hydrogenation process of silicon-containing oil products.

[0025] Furthermore, the silicon-capturing catalyst does not need to be sulfurized before use.

[0026] Compared with the prior art, the silicon capture catalyst of the present invention has the following advantages:

[0027] In the process of preparing the silicon-capturing catalyst of the present invention, a sulfided catalyst precursor is heat-treated with an aqueous solution containing a hydroxyl organic matter. Firstly, the hydroxyl content on the surface of the catalyst can be greatly increased, thereby improving the silicon-capturing ability and silicon-holding capacity of the catalyst. Secondly, the heat treatment process can modify the micromorphology of the active metal sulfide, increase the active sites, and improve the hydrogenation performance of the catalyst, thereby inhibiting the coking of the catalyst and occupying the silicon-capturing active sites. Thirdly, the microstructure of the surface of the alumina carrier can be modified, thereby generating more grooves on the catalyst surface, increasing the specific surface area of ​​the catalyst, and thereby improving the silicon-holding capacity.

[0028] Other features and advantages of the present invention will be described in detail in the following detailed description. DETAILED DESCRIPTION

[0029] 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.

[0030] 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.

[0031] 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.

[0032] In the following examples and comparative examples, the contents of metal sulfide and alumina are calculated based on the feed amounts.

[0033] Example 1

[0034] (1) An impregnation solution containing ammonium heptamolybdate and nickel nitrate was impregnated into an alumina support in equal volumes. After impregnation, the support was dried at 110°C for 3 hours and then sulfided with hydrogen containing 1.5% H2S at a temperature of 330°C, a pressure of 3.2 MPa, and a time of 5 hours. The support was then cooled to room temperature in a N2 atmosphere to obtain a catalyst precursor.

[0035] (2) A 4.2 g / mL propylene glycol aqueous solution was added to the catalyst precursor prepared in step (1), and the temperature was controlled at 120°C for hydrothermal treatment for 5 hours. The mixture was then cooled to room temperature, filtered, and dried at 80°C in a nitrogen atmosphere for 3 hours to obtain silicon scavenger C-1.

[0036] The weight percentages of the components in silicon scavenger C-1 are: MoS2 is 9.4%, NiS is 3.4%, and the rest is aluminum oxide.

[0037] Example 2

[0038] (1) An impregnation solution containing ammonium heptamolybdate and cobalt nitrate was impregnated into an alumina support in equal volumes. After impregnation, the solution was dried at 120°C for 3 hours and then sulfided with hydrogen containing 2.5% H2S at a temperature of 320°C, a pressure of 3.6 MPa, and a time of 5 hours. The solution was then cooled to room temperature in a N2 atmosphere to obtain a catalyst precursor.

[0039] (2) An ethylene glycol aqueous solution with a content of 0.8 g / mL was added to the catalyst precursor prepared in step (1), and the temperature was controlled at 110°C for hydrothermal treatment for 8 hours. The mixture was then cooled to room temperature, filtered, and dried at 90°C in a nitrogen atmosphere for 3 hours to obtain silicon scavenger C-2.

[0040] The weight percentages of the components in the silicon scavenger C-2 are: MoS2 is 9.0%, CoS is 3.7%, and the rest is aluminum oxide.

[0041] Example 3

[0042] (1) An impregnation solution containing ammonium heptamolybdate, nickel nitrate and cobalt nitrate was impregnated into an alumina support in equal volumes. After impregnation, the solution was dried at 120°C for 3 hours and then sulfided with hydrogen containing 1.5% H2S at a temperature of 360°C, a pressure of 4.6 MPa and a time of 5 hours. The solution was then cooled to room temperature in a N2 atmosphere to obtain a catalyst precursor.

[0043] (2) A 1.6 g / mL propylene glycol aqueous solution was added to the catalyst precursor prepared in step (1), and the temperature was controlled at 160°C for hydrothermal treatment for 6 hours. The mixture was then cooled to room temperature, filtered, and dried at 90°C in a nitrogen atmosphere for 4 hours to obtain silicon scavenger C-3.

[0044] The weight percentages of the components in the silicon scavenger C-3 are: MoS2 is 9.7%, CoS is 2.1%, NiS is 2.1%, and the rest is aluminum oxide.

[0045] Example 4

[0046] (1) An impregnation solution containing ammonium metatungstate and nickel nitrate was impregnated into an alumina carrier in equal volumes. After impregnation, the carrier was dried at 120°C for 3 hours. The carrier was then sulfided with hydrogen containing 1.5% H2S at a temperature of 380°C, a pressure of 4.2 MPa, and a time of 8 hours. The carrier was then cooled to room temperature in a N2 atmosphere to obtain a catalyst precursor.

[0047] (2) A 2.7 g / mL butanediol aqueous solution was added to the catalyst precursor prepared in step (1), and the temperature was controlled at 180°C for hydrothermal treatment for 6 hours. The mixture was then cooled to room temperature, filtered, and dried at 80°C in a nitrogen atmosphere for 6 hours to obtain silicon scavenger C-4.

[0048] The weight percentages of the components in the silicon scavenger C-4 are: WS2 is 9.9%, NiS is 3.7%, and the rest is aluminum oxide.

[0049] Example 5

[0050] (1) An impregnation solution containing ammonium metatungstate and cobalt nitrate was impregnated into an alumina carrier in equal volumes. After impregnation, the carrier was dried at 180°C for 3 hours. The carrier was then sulfided with hydrogen containing 1.5% H2S at a temperature of 360°C, a pressure of 4.6 MPa, and a time of 8 hours. The carrier was then cooled to room temperature in a N2 atmosphere to obtain a catalyst precursor.

[0051] (2) A 3.8 g / mL butanediol aqueous solution was added to the catalyst precursor prepared in step (1), and the temperature was controlled at 180°C for hydrothermal treatment for 8 hours. The mixture was then cooled to room temperature, filtered, and dried at 80°C in a nitrogen atmosphere for 6 hours to obtain silicon scavenger C-5.

[0052] The weight percentages of the components in the silicon scavenger C-5 are: WS2 is 8.6%, CoS is 3.8%, and the rest is aluminum oxide.

[0053] Example 6

[0054] (1) An impregnation solution containing ammonium metatungstate, nickel nitrate and cobalt nitrate was impregnated into an alumina carrier in equal volumes. After impregnation, the carrier was dried at 180°C for 3 hours and then sulfided with hydrogen containing 1.5% H2S at a temperature of 360°C, a pressure of 4.6 MPa and a time of 8 hours. The carrier was then cooled to room temperature in a N2 atmosphere to obtain a catalyst precursor.

[0055] (2) A 4.8 g / mL pentanediol aqueous solution was added to the catalyst precursor prepared in step (1), and the temperature was controlled at 180°C for hydrothermal treatment for 6 hours. The mixture was then cooled to room temperature, filtered, and dried at 80°C in a nitrogen atmosphere for 6 hours to obtain silicon scavenger C-6.

[0056] The weight percentages of the components in the silicon scavenger C-6 are: WS2 is 12.1%, NiS is 2.9%, CoS is 1.9%, and the rest is aluminum oxide.

[0057] Example 7

[0058] (1) An impregnation solution containing ammonium metatungstate, ammonium heptamolybdate and nickel nitrate was impregnated into an alumina carrier in equal volumes. After impregnation, the carrier was dried at 180°C for 3 hours and then sulfided with hydrogen containing 1.5% H2S at a temperature of 380°C, a pressure of 4.6 MPa and a time of 8 hours. The carrier was then cooled to room temperature in a N2 atmosphere to obtain a catalyst precursor.

[0059] (2) A 5.8 g / mL propylene glycol aqueous solution was added to the catalyst precursor prepared in step (1), and the temperature was controlled at 130°C for hydrothermal treatment for 8 hours. The mixture was then cooled to room temperature, filtered, and dried at 80°C in a nitrogen atmosphere for 6 hours to obtain silicon scavenger C-7.

[0060] The weight percentages of the components in the silicon scavenger C-7 are: WS2 is 6.3%, MoS2 is 6.5%, NiS is 4.1%, and the rest is alumina.

[0061] Comparative Example 1

[0062] In step (1), no sulfidation treatment was performed, and the other steps were the same as in Example 1. In step (2), the hydrothermal treatment was followed by sulfidation treatment, and the other operation processes were the same as in Example 1, to obtain a comparative silicon trapping agent DC-1.

[0063] The weight percentages of the components in the comparative silicon capture agent DC-1 are as follows: MoS2 is 9.4%, NiS is 3.4%, and the rest is aluminum oxide.

[0064] Comparative Example 2

[0065] Step (1) is the same as in Example 1. The concentration of propylene glycol in step (2) is 15.2 g / mL, and the other steps are the same as in Example 1, to obtain a comparative silicon capture catalyst DC-2.

[0066] The weight percentages of the components in the comparative silicon capture catalyst DC-2 are as follows: MoS2 is 9.4%, NiS is 3.4%, and the rest is alumina.

[0067] Comparative Example 3

[0068] Step (1) is the same as in Example 1. In step (2), no water is added to the propylene glycol, which is pure propylene glycol. The other steps are the same as in Example 1, and a comparative silicon capture catalyst DC-3 is obtained.

[0069] The weight percentages of the components in the comparative silicon capture catalyst DC-3 are as follows: MoS2 is 9.4%, NiS is 3.4%, and the rest is alumina.

[0070] Comparative Example 4

[0071] Step (1) is the same as in Example 1. Step (2) is omitted, and a comparative silicon capture catalyst DC-4 is obtained.

[0072] The weight percentages of the components in the comparative silicon capture catalyst DC-4 are as follows: MoS2 is 9.4%, NiS is 3.4%, and the rest is alumina.

[0073] The physicochemical properties of the silicon-trapping catalysts C-1 to C-7 prepared in the above examples and the silicon-trapping catalysts DC-1 to DC-4 prepared in the comparative examples were analyzed. The analysis results are shown in Table 1.

[0074] Table 1.

[0075]

[0076] Example 8

[0077] This example illustrates the silicon capture activity of the catalyst provided by the present invention for coker naphtha.

[0078] The raw oil used for evaluation was coking naphtha provided by a refinery of Sinopec. Its main properties are as follows: sulfur content of 3386μg / g, nitrogen content of 84μg / g, and silicon content of 89μg / g. A 200mL fixed-bed hydrogenation unit was used to evaluate the silicon capture capacity of silicon capture catalysts C-1 to C-7 and comparative examples DC-1 to DC-4. The evaluation reaction conditions were: operating pressure of 3.0MPa, reaction temperature of 290℃, hydrogen / oil volume ratio of 200:1, and volume space velocity of 6.0h -1 After running for 500 hours, the silicon capture catalyst was unloaded and then calcined at 500℃ in a nitrogen atmosphere for 3 hours. The SiO2 content in the silicon capture catalyst was analyzed by XRF. The evaluation results are shown in Table 2.

[0079] Table 2.

[0080]

[0081] As can be seen from Table 2, the silicon-capturing catalyst of the present invention has a high silicon-holding capacity and relatively high hydrodesulfurization and hydrodenitrogenation activities.

Claims

1. A method for preparing a silicon capture catalyst, comprising the following steps: (1) impregnating an alumina support with an impregnation solution containing a Group VIB metal salt and a Group VIII metal salt, and then drying and sulfurizing the alumina support to obtain a catalyst precursor; (2) adding the catalyst precursor in step (1) to an aqueous solution of a hydroxyl-containing organic compound for hydrothermal treatment; and then drying to obtain a silicon capture catalyst; wherein the hydroxyl-containing organic compound is a C2-C10 alcohol, and the hydroxyl-containing organic compound in the aqueous solution is 0.1 g / mL-10 g / mL; the conditions of the hydrothermal treatment are: temperature of 60-200°C, and time of 3-10 h; The specific surface area of ​​the silicon capture catalyst is 300-500m 2 / g, and the surface hydroxyl content is 1000-3000µmol / g.

2. The preparation method according to claim 1, characterized in that The hydroxyl-containing organic compound is selected from at least one of ethanol, ethylene glycol, glycerol, butanediol and pentanediol.

3. The preparation method according to claim 1, characterized in that In the aqueous solution of the hydroxyl-containing organic matter, the hydroxyl-containing organic matter contains 0.5 g / mL-6.0 g / mL.

4. The preparation method according to claim 1, characterized in that The pressure of the hydrothermal treatment in step (2) is the autogenous pressure in the closed container.

5. The preparation method according to claim 1, characterized in that The drying conditions in step (2) are: drying temperature 50-90°C, and drying time 3-6 hours.

6. The preparation method according to claim 1, characterized in that During the impregnation process of step (1), an organic auxiliary agent is further added, wherein the organic auxiliary agent is a C3-C10 alcohol and / or an organic acid.

7. The preparation method according to claim 6, characterized in that The organic auxiliary agent is selected from at least one of glycerol, butylene glycol, pentanediol, citric acid, malonic acid, succinic acid and glutaric acid.

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

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

10. Use of the silicon-trapping catalyst according to claim 9, wherein the catalyst is used in the hydrogenation process of silicon-containing oil products.

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