Multicomponent catalysts, their preparation methods and applications

Abstract

This invention discloses a multi-component catalyst, its preparation method, and its applications. The preparation method of the multi-component catalyst of this invention includes: mixing a dispersion containing a metal precursor with a dispersion containing a synthetic molecular sieve, and sequentially subjecting the mixture to hydrothermal treatment and / or aging, washing, drying, and calcination; or, mixing a dispersion containing a metal precipitate with a dispersion containing a molecular sieve mother liquor, and sequentially subjecting the mixture to hydrothermal treatment and / or aging, washing, drying, and calcination. The catalyst prepared by the method of this invention has small and uniformly distributed component particles, and when applied to syngas-to-olefins / aromatics reactions, it has the advantages of high feedstock conversion rate and high selectivity for aromatic / light hydrocarbon products.

Description

Technical Field

[0001] This invention relates to a multi-component catalyst, its preparation method, and its application. Background Technology

[0002] Aromatics are important basic raw materials in the chemical industry and have been widely used in the manufacture of synthetic resins, synthetic fibers, synthetic rubber, and other products. New non-petroleum-based technologies for producing aromatics have been researched and developed. Among these, routes using syngas as a feedstock for the preparation of aromatic compounds mainly fall into two categories: the alcohol synthesis route and the Fischer-Tropsch synthesis route. The alcohol synthesis route is an indirect synthetic route that can draw upon existing mature processes, but its production process is relatively long and requires significant equipment investment. The Fischer-Tropsch synthesis produces a wide product distribution but is limited by the Anderson-Schulz-Flory distribution, resulting in lower selectivity for aromatic products.

[0003] The one-step process based on a multifunctional catalyst for CO hydrogenation-intermediate conversion not only has advantages in terms of fixed cost, but also provides the possibility of achieving efficient coupling between multiple steps and promoting the shift of reaction equilibrium, thus possessing both academic and applied value. CDChang et al. (Synthesis gas conversion to aromatic hydrocarbons. Journal of Catalysis, 1979, 56(2): 268-273) applied ZnO-Cr2O3 and HZSM-5 to a syngas-to-aromatics system, achieving a total aromatic hydrocarbon selectivity of nearly 70%. E. Javier et al. (Industrial & Engineering Chemistry Research, 1998, 37, 1211-1219) mechanically mixed Cr2O3-ZnO with HZSM-5 molecular sieve with a silicon-to-aluminum ratio of Si / Al = 154, realizing the direct production of gasoline from syngas via methanol. K. Cheng et al. (Chem., 2017, 3, 1-14), J. Yang et al. (Chemical Communications, 2017, 53, 11146-11149), Z. Huang et al. (Chem. Cat. Chem., 2018, 10, 4519-4524), and W. Zhou et al. (Chem. Cat. Chem., 2019, 11, 1-9) coupled Zn-Zr oxides, Zn-Cr oxides, Ce-Zr oxides, and Mo-Zr oxides with ZSM-5 molecular sieves to achieve the conversion of syngas into aromatics.

[0004] CN106540740A discloses a catalyst for the highly selective production of light aromatics from syngas and its preparation method. Specifically, the catalyst is composed of modified zeolite molecular sieves and zirconium-containing composite oxides; the content of zirconium-containing composite oxides is 20%–60% by mass, and the content of modified zeolite molecular sieves is 40%–80%. The catalyst preparation method involves: adding the zirconium-containing composite oxides to a solvent and ultrasonically dispersing them to obtain solution A; adding the modified zeolite molecular sieves to solution A; filtering the ultrasonically dispersed mixture, washing, and drying the resulting filter cake; grinding the dried sample into powder; and calcining the powder sample to obtain the catalyst for the highly selective production of light aromatics from syngas. It can produce light aromatics with high selectivity and good stability.

[0005] CN107486234A discloses a catalyst for the direct conversion of syngas to produce light aromatics and its preparation method. The catalyst preparation steps are as follows: (1) Dissolve inorganic cerium salt and inorganic zirconium salt in deionized water to obtain a mixed solution of inorganic cerium salt and inorganic zirconium salt, wherein the molar content of cerium is 5%-95% and the molar content of zirconium is 95%-5%; (2) Add a certain amount of precipitant to deionized water to form a clear aqueous solution; then add a certain amount of surfactant and stir at room temperature. (3) Mix the solution obtained in step (1) with the clear solution obtained in step (2), stir at 40-80℃ for 2-12h, and then hydrothermally react at 120-160℃ for 5-24h; (4) Mix the solid-liquid mixture obtained after hydrothermal reaction with silicon-aluminum solid acid and then wet ball mill it, then filter, wash with ethanol, vacuum dry it, and then calcine the obtained solid in air atmosphere for 4-24h at a calcination temperature of 450-700℃ to obtain the catalyst.

[0006] Existing technologies disclose the application of zirconium-containing composite oxide-modified zeolite molecular sieves and modified cerium-zirconium solid solution-hierarchical porous silica-alumina solid acid materials in syngas conversion to light aromatics. However, these multifunctional catalysts are mostly prepared by physically mixing synthesized metal oxides and molecular sieves, resulting in long preparation processes and large amounts of alkaline wastewater discharge. In addition, it is difficult to ensure the uniformity of dispersion of each component, leading to a reduction in catalytic performance. Summary of the Invention

[0007] To address the aforementioned problems in existing technologies, this invention provides a novel method for preparing multi-component catalysts. This method can shorten the catalyst synthesis process and improve its economic efficiency. The catalyst prepared using the method of this invention has small and uniformly distributed component particles. When applied to syngas-to-olefins / aromatics reactions, it exhibits advantages such as high feedstock conversion rate and high selectivity for aromatic / light hydrocarbon products.

[0008] The first aspect of this invention provides a method for preparing a multi-component catalyst, comprising: mixing a dispersion containing a metal precursor with a dispersion containing a synthetic molecular sieve, and sequentially subjecting the mixture to hydrothermal treatment and / or aging treatment, washing, drying, and calcination; or,

[0009] The dispersion containing metal precipitates is mixed with the dispersion containing molecular sieve mother liquor, and then subjected to hydrothermal treatment and / or aging treatment, washing, drying and calcination in sequence.

[0010] In this invention, the term "synthetic molecular sieve" refers to a molecular sieve obtained by hydrothermal crystallization of the molecular sieve mother liquor without calcination.

[0011] In this invention, the content of the metal precursor in the dispersion containing the metal precursor can be 2-80% by weight. The metal precursor is calculated as the metal oxide in the prepared multi-component catalyst. The dispersion can be, but is not limited to, an aqueous solution.

[0012] In this invention, the content of synthetic molecular sieve in the dispersion containing synthetic molecular sieve can be 2-80% by weight. The synthetic molecular sieve is defined as the molecular sieve in the prepared multi-component catalyst. The dispersion can be, but is not limited to, an aqueous solution.

[0013] In this invention, the content of the metal precipitate in the dispersion containing the metal precipitate can be 2-80% by weight. The metal precipitate is calculated as the metal oxide in the prepared multi-component catalyst. The dispersion can be, but is not limited to, an aqueous solution.

[0014] In this invention, the content of the molecular sieve mother liquor in the dispersion containing the mother liquor can be 2-80% by weight. The molecular sieve mother liquor is calculated based on the molecular sieve in the prepared multi-component catalyst. The dispersion can be, but is not limited to, an aqueous solution. The method of this invention includes adding a metal precursor (metal salt) and optionally a second alkali source to the dispersion of the synthesized molecular sieve, followed by hydrothermal treatment and / or aging treatment, preferably aging treatment; or, the method of this invention includes adding the molecular sieve mother liquor to the dispersion of the metal precipitate, followed by hydrothermal treatment and / or aging treatment, preferably hydrothermal treatment. The method of this invention can shorten the catalyst synthesis process, improve the economics of the process, and produce catalyst components with small particle size and uniform distribution. Under the action of the catalyst prepared by the method of this invention, syngas can be efficiently converted into aromatics and / or light hydrocarbon products, with high conversion rate and high selectivity for aromatics / light hydrocarbons.

[0015] According to some embodiments of the present invention, preferably, the method for preparing the dispersion containing the synthetic molecular sieve includes: mixing a silicon source, an aluminum source, a template agent, an optional ammonium compound and / or a first alkali source to obtain a molecular sieve mother liquor, and then performing hydrothermal crystallization treatment.

[0016] According to some embodiments of the present invention, washing is preferably performed after hydrothermal crystallization treatment. Washing can be done with water, and preferably, the number of washes is 1 to 5.

[0017] According to some embodiments of the present invention, the silicon source may be, but is not limited to, at least one of: tetraethyl orthosilicate, methyl orthosilicate, silica sol, sodium silicate, and silica fume.

[0018] According to some embodiments of the present invention, the aluminum source may be, but is not limited to, at least one of aluminum isopropoxide, sodium aluminate, aluminum sol, aluminum nitrate, and aluminum hydroxide.

[0019] According to some embodiments of the present invention, the template agent may be, but is not limited to, at least one of tetrapropylammonium hydroxide, tetrapropylammonium bromide, tetraethyl sodium hydroxide, tetraethylammonium bromide, n-butylamine, and triethylamine.

[0020] According to some embodiments of the present invention, the ammonium compound may be, but is not limited to, at least one of urea, ammonia, ammonium carbonate and ammonium bicarbonate.

[0021] According to some embodiments of the present invention, the first alkali source may be, but is not limited to, at least one of sodium hydroxide, sodium carbonate, and sodium bicarbonate.

[0022] According to some embodiments of the present invention, in the preparation process of the dispersion containing the synthetic molecular sieve, the molar ratio of silicon source (calculated as SiO2), aluminum source (calculated as Al2O3), template agent, ammonium compound, and first alkali source can be 1:0~0.033:0.2~4.0:0~5.0:0~2.0.

[0023] According to some embodiments of the present invention, preferably, the hydrothermal crystallization treatment includes: a temperature of 100-180°C, preferably 105-170°C; and a time of 12-100 hours, preferably 24-96 hours.

[0024] According to some embodiments of the present invention, the metal precursor may be a soluble salt or acid containing at least one metal selected from Cr, Mn, Ce, Zr, Zn, In and Ga.

[0025] According to some embodiments of the present invention, preferably, the weight ratio of the metal precursor to the synthetic molecular sieve is 0.02 to 50:1; more preferably, it is 0.1 to 10:1, wherein the metal precursor is calculated based on the metal oxide in the prepared multi-component catalyst, and the synthetic molecular sieve is calculated based on the molecular sieve in the prepared multi-component catalyst.

[0026] According to some embodiments of the present invention, preferably, the method for preparing the dispersion containing the metal precipitate includes: mixing the metal precursor with a second alkali source and aging it.

[0027] According to some embodiments of the present invention, washing is preferably performed after aging treatment. Washing can be done with water, and preferably, the number of washes is 1 to 5.

[0028] According to some embodiments of the present invention, the metal precursor may be a soluble salt or acid containing at least one metal selected from Cr, Mn, Ce, Zr, Zn, In and Ga.

[0029] According to some embodiments of the present invention, the second alkali source may be, but is not limited to, at least one of ammonium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide and ammonia water.

[0030] According to some embodiments of the present invention, preferably, the amount of the second alkali source added can be 1 to 1.1, based on the theoretical amount of the second alkali source required to completely precipitate the metal precursor being 1.

[0031] According to some embodiments of the present invention, preferably, the aging conditions include: a pH value of 7 to 11, more preferably 7 to 9; an aging temperature of 40 to 100°C, more preferably 50 to 80°C; and an aging time of 2 to 72 hours, more preferably 4 to 24 hours.

[0032] According to some embodiments of the present invention, preferably, the weight ratio of metal precipitate to molecular sieve mother liquor is 0.02 to 50:1; more preferably, it is 0.1 to 10:1, wherein the metal precipitate is calculated based on the metal oxides in the prepared multi-component catalyst, and the molecular sieve mother liquor is calculated based on the molecular sieves in the prepared multi-component catalyst.

[0033] According to some embodiments of the present invention, preferably, the crystallization conditions include: a crystallization temperature of 100–180°C, more preferably 105–170°C; and a crystallization time of 12–100 hours, more preferably 24–96 hours.

[0034] According to some embodiments of the present invention, preferably, the aging conditions include: a pH value of 7 to 11, more preferably 7 to 9; an aging temperature of 40 to 100°C, more preferably 50 to 80°C; and an aging time of 2 to 72 hours, more preferably 4 to 24 hours.

[0035] A second aspect of the present invention provides a multi-component catalyst obtained according to the preparation method described above. Preferably, the metal oxide is uniformly distributed on the outer surface of the molecular sieve, more preferably 60% of the outer surface of the molecular sieve is covered with metal oxide, and more preferably 80% of the outer surface of the molecular sieve is covered with metal oxide. The multi-component catalyst of the present invention has small particle size and uniform distribution, for example...Figure 1 , Figure 2 and Figure 3 As shown.

[0036] A third aspect of the present invention provides a method for producing aromatics and / or light hydrocarbons from syngas, comprising: using syngas as a raw material, contacting the raw material with a multi-component catalyst obtained according to the above preparation method or the above-described multi-component catalyst to react and obtain a stream containing aromatics and / or light hydrocarbons.

[0037] According to some embodiments of the present invention, preferably, the H2 / CO molar ratio in the synthesis gas is 0.3 to 4, and more preferably, the H2 / CO molar ratio is 0.5 to 2.

[0038] According to some embodiments of the present invention, preferably, the reaction conditions include a reaction temperature of 320–480°C.

[0039] According to some embodiments of the present invention, preferably, the reaction conditions include a reaction pressure of 0.6 to 9.5 MPa.

[0040] According to some embodiments of the present invention, preferably, the reaction conditions include a volume hourly space velocity of 1200–18000 h⁻¹. -1 .

[0041] The beneficial effects of this invention are:

[0042] This invention provides a method for the direct synthesis of oxide-molecular sieve bifunctional catalysts. This method shortens the catalyst synthesis process and improves its economic efficiency. The catalysts prepared using this method have small and uniformly distributed particle sizes, and when applied to syngas-to-olefins / aromatics reactions, they exhibit advantages such as high conversion rates and high selectivity for aromatics / light hydrocarbons. Attached Figure Description

[0043] Figure 1 This is a SEM image of the multi-component catalyst provided in Example 1 of the present invention.

[0044] Figure 2 This is a SEM image of the multi-component catalyst provided in Example 2 of the present invention.

[0045] Figure 3 This is a SEM image of the multi-component catalyst provided in Example 3 of the present invention.

[0046] Figure 4 This is a SEM image of the multi-component catalyst provided in Comparative Example 1 of the present invention.

[0047] Figure 5 The XRD patterns of the multi-component catalysts are shown. In the figure, (1), (2), (3), and (4) are the multi-component catalysts obtained in Comparative Example 1, Example 1, Example 2, and Example 3, respectively. Detailed Implementation

[0048] To make the present invention easier to understand, the present invention will be described in detail below with reference to embodiments. These embodiments are for illustrative purposes only and are not limited to the scope of application of the present invention.

[0049] The testing method and equipment used in this invention are as follows:

[0050] (1) The instruments and conditions for XRD testing of the catalyst are as follows: Under room temperature conditions, the obtained catalyst was analyzed by a Bruker D8Advance X-ray diffractometer. The test was performed using a Cu-Kα1 X-ray source (λ=0.15405nm) and a graphite monochromator. The tube voltage was 40kV, the tube current was 50mA, and the scanning range was 5~90°.

[0051] (2) The instruments and conditions for SEM testing of the catalyst are as follows: the morphology and structure of the catalyst are observed using a scanning electron microscope (Zeiss Merlin) with an accelerating voltage of 2.0 kV.

[0052]

Example 1

[0053] (1) Preparation of a dispersion containing the synthetic molecular sieve (the synthetic ZSM-5 molecular sieve was synthesized by a hydrothermal method):

[0054] 0.69 g of aluminum isopropoxide was added to a mixed solution containing 41.20 g of tetrapropylammonium hydroxide solution (25 wt%) and 29.88 g of deionized water to obtain a mixture. The mixture was stirred at room temperature for 12 h, and then 35.17 g of tetraethyl orthosilicate was added dropwise. After stirring for another 12 h, 25.35 g of urea was added to the mixture, and stirring was continued for 1 h to obtain a molecular sieve mother liquor. The molecular sieve mother liquor was transferred to a high-pressure reactor lined with polytetrafluoroethylene and hydrothermally treated in an oven at 180 °C for 48 h to obtain a dispersion containing the synthesized molecular sieve.

[0055] (2) A multi-component catalyst was prepared by mixing a dispersion containing a metal precursor with a dispersion containing a synthetic molecular sieve.

[0056] The 132.28g dispersion containing the synthetic molecular sieve obtained in step (1) was centrifuged, washed three times with deionized water, and dispersed in 100mL of deionized water to obtain a washed dispersion containing the synthetic molecular sieve, which was then placed in a 70℃ constant temperature water bath. 52.66g of chromium nitrate was dissolved in 70mL of deionized water, and 19.91g of ammonium carbonate was dissolved in 94.0mL of deionized water. Under vigorous stirring, the chromium nitrate solution and the ammonium carbonate solution were added dropwise to the washed dispersion containing the synthetic molecular sieve. After precipitation, the mother liquor was aged in a 70℃ constant temperature water bath for 3 hours, then filtered, washed with deionized water until neutral, and the resulting filter cake was dried overnight in a 100℃ oven and then calcined at 550℃ for 5 hours (heating rate 5℃ / min) to obtain catalyst SSL-1. The SEM and XRD patterns of this catalyst are shown below. Figure 1 and Figure 5 .

[0057]

Example 2

[0058] (1) Preparation of a dispersion containing synthetic molecular sieves:

[0059] As in Example 1, a dispersion of the synthetic molecular sieve was obtained.

[0060] (2) A multi-component catalyst was prepared by mixing a dispersion containing a metal precursor with a dispersion containing a synthetic molecular sieve.

[0061] The 132.28g dispersion containing the synthetic molecular sieve obtained in step (1) was centrifuged, washed once with deionized water, and dispersed in 100mL of deionized water to obtain a washed dispersion containing the synthetic molecular sieve, which was then placed in a 70℃ constant temperature water bath. 52.66g of chromium nitrate was dissolved in 70mL of deionized water, and 19.91g of ammonium carbonate was dissolved in 94.0mL of deionized water. Under vigorous stirring, the chromium nitrate solution and the ammonium carbonate solution were added dropwise to the washed dispersion containing the synthetic molecular sieve. After precipitation, the mother liquor was aged in a 70℃ constant temperature water bath for 3h, then filtered, washed with deionized water until neutral, and the resulting filter cake was dried overnight in a 100℃ oven, and then calcined at 550℃ for 5h (heating rate 5℃ / min) to obtain catalyst SSL-2. The SEM and XRD patterns of this catalyst are shown below. Figure 2 and Figure 5 .

[0062]

Example 3

[0063] (1) Preparation of a dispersion containing synthetic molecular sieves:

[0064] As in Example 1, a dispersion of the synthetic molecular sieve was obtained.

[0065] (2) A multi-component catalyst was prepared by mixing a dispersion containing a metal precursor with a dispersion containing a synthetic molecular sieve.

[0066] 132.28 g of the dispersion containing the synthetic molecular sieve obtained in step (1) was placed in a 70°C constant temperature water bath. 52.66 g of chromium nitrate was dissolved in 70 mL of deionized water, and the chromium nitrate solution was added dropwise to the above dispersion containing the synthetic molecular sieve under vigorous stirring. After precipitation, the mother liquor was aged in a 70°C constant temperature water bath for 3 h, then filtered, washed with deionized water until neutral, and the resulting filter cake was dried overnight in a 100°C oven, and then calcined at 550°C for 5 h (heating rate 5°C / min) to obtain catalyst SSL-3. The SEM and XRD patterns of this catalyst are shown below. Figure 3 and Figure 5 .

[0067]

Example 4

[0068] (1) Preparation of a dispersion containing synthetic molecular sieves:

[0069] As in Example 1, a dispersion of the synthetic molecular sieve was obtained.

[0070] (2) A multi-component catalyst was prepared by mixing a dispersion containing a metal precursor with a dispersion containing a synthetic molecular sieve.

[0071] The 132.28g dispersion containing the synthetic molecular sieve obtained in step (1) was centrifuged, washed three times with deionized water, and dispersed in 100mL of deionized water to obtain a washed dispersion containing the synthetic molecular sieve, which was then placed in a 70℃ constant temperature water bath. 100.93g of manganese nitrate aqueous solution (50% by weight) was mixed with 19.54mL of deionized water, and 28.44g of ammonium carbonate was dissolved in 94.0mL of deionized water. Under vigorous stirring, the above manganese nitrate solution and ammonium carbonate solution were added dropwise to the washed dispersion containing the synthetic molecular sieve. After precipitation, the mother liquor was aged in a 60℃ constant temperature water bath for 4h, then filtered, washed with deionized water until neutral, and the resulting filter cake was dried overnight in a 100℃ oven and then calcined at 550℃ for 5h (heating rate 5℃ / min) to obtain catalyst SSL-4.

[0072]

Example 5

[0073] (1) Preparation of a dispersion containing chromium precipitate:

[0074] Chromium nitrate nonahydrate was used as the chromium source, and ammonium carbonate as the alkali source. 52.66 g of chromium nitrate was dissolved in 70 mL of deionized water; 19.91 g of ammonium carbonate was dissolved in 94 mL of deionized water. The chromium nitrate solution and ammonium carbonate solution were added dropwise to 20 mL of deionized water in a constant temperature water bath at 70 °C with vigorous stirring. After precipitation, the mother liquor was aged in a constant temperature water bath at 70 °C for 3 hours to obtain a dispersion containing chromium precipitate.

[0075] (2) Preparation of a dispersion containing molecular sieve mother liquor:

[0076] 0.69 g of aluminum isopropoxide was added to a mixed solution containing 41.20 g of tetrapropylammonium hydroxide solution (25 wt%) and 29.88 g of deionized water to obtain a mixture. The mixture was stirred at room temperature for 12 h, and then 35.17 g of tetraethyl orthosilicate was added dropwise. After stirring for another 12 h, 25.35 g of urea was added to the mixture, and stirring was continued for 1 h to obtain a dispersion containing molecular sieve mother liquor.

[0077] (3) A multi-component catalyst was prepared by mixing a dispersion containing chromium precipitate with a dispersion containing molecular sieve mother liquor.

[0078] The dispersion containing chromium precipitate obtained in step (1) was centrifuged, washed three times with deionized water, and dispersed in 100 mL of deionized water to obtain a washed dispersion containing chromium precipitate. Under vigorous stirring, the dispersion of 132.28 g of molecular sieve mother liquor was added dropwise to the washed dispersion containing chromium precipitate. After mixing, hydrothermal treatment was performed at 180 °C for 48 hours. The mixture was then filtered, washed with deionized water until neutral, and the resulting filter cake was dried overnight in a 100 °C oven and then calcined at 550 °C for 5 hours (heating rate 5 °C / min) to obtain catalyst SSL-5.

[0079]

Example 6

[0080] (1) Preparation of a dispersion containing chromium precipitate:

[0081] Same as in Example 5, a dispersion containing chromium precipitate was obtained.

[0082] (2) Preparation of a dispersion containing molecular sieve mother liquor:

[0083] Same as in Example 5, a dispersion containing molecular sieve mother liquor was obtained.

[0084] (3) A multi-component catalyst was prepared by mixing a dispersion containing chromium precipitate with a dispersion containing molecular sieve mother liquor.

[0085] The dispersion containing chromium precipitate obtained in step (1) was centrifuged, washed once with deionized water, and dispersed in 100 mL of deionized water to obtain a washed dispersion containing chromium precipitate. Under vigorous stirring, 132.28 g of the dispersion containing the molecular sieve mother liquor was added dropwise to the washed dispersion containing chromium precipitate. After mixing, hydrothermal treatment was performed at 180 °C for 48 hours. The mixture was then filtered, washed with deionized water until neutral, and the resulting filter cake was dried overnight in a 100 °C oven and then calcined at 550 °C for 5 hours (heating rate 5 °C / min) to obtain catalyst SSL-6.

[0086]

Example 7

[0087] (1) Preparation of a dispersion containing chromium precipitate:

[0088] Same as in Example 5, a dispersion containing chromium precipitate was obtained.

[0089] (2) Preparation of a dispersion containing molecular sieve mother liquor:

[0090] Same as in Example 5, a dispersion containing molecular sieve mother liquor was obtained.

[0091] (3) A multi-component catalyst was prepared by mixing a dispersion containing chromium precipitate with a dispersion containing molecular sieve mother liquor.

[0092] 256.57 g of the dispersion containing chromium precipitate obtained in step (1) was added dropwise to the above dispersion containing chromium precipitate under vigorous stirring with 132.28 g of the dispersion containing molecular sieve mother liquor. After mixing, hydrothermal treatment was performed at 180 °C for 48 hours, followed by filtration and washing with deionized water until neutral. The resulting filter cake was dried overnight in an oven at 100 °C and then calcined at 550 °C for 5 hours (heating rate 5 °C / min) to obtain catalyst SSL-7.

[0093]

Example 8

[0094] (1) Preparation of a dispersion containing manganese precipitate:

[0095] Using a 50% (w / w) manganese nitrate aqueous solution as the metal precursor and sodium carbonate as the alkali source, 100.93 g of manganese nitrate solution was mixed with 19.54 mL of deionized water; 31.37 g of sodium carbonate was dissolved in 94 mL of deionized water. The manganese nitrate solution and sodium carbonate solution were added dropwise to 20 mL of deionized water in a constant temperature water bath at 60 °C with vigorous stirring. After precipitation, the mother liquor was aged in a constant temperature water bath at 60 °C for 4 h to obtain a dispersion containing manganese precipitate.

[0096] (2) Preparation of a dispersion containing molecular sieve mother liquor:

[0097] Same as in Example 5, a dispersion containing molecular sieve mother liquor was obtained.

[0098] (3) A multi-component catalyst was prepared by mixing a dispersion containing manganese precipitate with a dispersion containing molecular sieve mother liquor.

[0099] The dispersion containing manganese precipitate obtained in step (1) was centrifuged, washed three times with deionized water, and dispersed in 100 mL of deionized water to obtain a washed dispersion containing manganese precipitate. Under vigorous stirring, 132.28 g of the dispersion containing molecular sieve mother liquor was added dropwise to the washed dispersion containing manganese precipitate. After mixing, hydrothermal treatment was performed at 170°C for 72 hours. The mixture was then filtered, washed with deionized water until neutral, and the resulting filter cake was dried overnight in a 100°C oven and then calcined at 550°C for 5 hours (heating rate 5°C / min) to obtain catalyst SSL-8.

[0100] Comparative Example 1

[0101] (1) Preparation of molecular sieves:

[0102] 0.69 g of aluminum isopropoxide was added to a mixed solution containing 41.20 g of tetrapropylammonium hydroxide solution (25 wt%) and 29.88 g of deionized water to obtain a mixture. The mixture was stirred at room temperature for 12 h, and then 35.17 g of tetraethyl orthosilicate was added dropwise. After stirring for another 12 h, 25.35 g of urea was added to the mixture, and stirring was continued for 1 h to obtain a molecular sieve mother liquor. The molecular sieve mother liquor was transferred to a high-pressure reactor lined with polytetrafluoroethylene and hydrothermally treated in an oven at 180 °C for 48 h to obtain a dispersion containing the synthesized molecular sieve. After centrifugation and repeated washing with deionized water until the supernatant was neutral, the solid product obtained after drying was calcined at 550 °C for 5 h (heating rate 5 °C / min) to obtain the molecular sieve.

[0103] (2) Mix the molecular sieve with a dispersion containing a metal precursor and prepare a multi-component catalyst:

[0104] 52.66 g of chromium nitrate was dissolved in 150 mL of deionized water, and 10 g of molecular sieve was dispersed in the chromium nitrate solution. The mixture was placed in a 70 °C constant temperature water bath. 19.91 g of ammonium carbonate was dissolved in 94.0 mL of deionized water. Under vigorous stirring, the ammonium carbonate solution was added dropwise to the above dispersion of molecular sieve and chromium nitrate. After precipitation, the mother liquor was aged in a 70 °C constant temperature water bath for 3 h, then filtered, washed with deionized water until neutral, and the resulting filter cake was dried in a 100 °C oven overnight, and then calcined at 500 °C for 1 h (heating rate 2 °C / min) to obtain catalyst SSL-D1. The SEM and XRD patterns of this catalyst are shown below. Figure 4 and Figure 5 .

[0105] Comparative Example 2

[0106] (1) Preparation of molecular sieves:

[0107] 0.69 g of aluminum isopropoxide was added to a mixed solution containing 41.20 g of tetrapropylammonium hydroxide solution (25 wt%) and 29.88 g of deionized water to obtain a mixture. The mixture was stirred at room temperature for 12 h, and then 35.17 g of tetraethyl orthosilicate was added dropwise. After stirring for another 12 h, 25.35 g of urea was added to the mixture, and stirring was continued for 1 h to obtain a molecular sieve mother liquor. The molecular sieve mother liquor was transferred to a high-pressure reactor lined with polytetrafluoroethylene and hydrothermally treated in an oven at 180 °C for 48 h to obtain a dispersion containing the synthesized molecular sieve. After centrifugation and repeated washing with deionized water until the supernatant was neutral, the solid product obtained after drying was calcined at 550 °C for 5 h (heating rate 5 °C / min) to obtain the molecular sieve.

[0108] (2) Mix the molecular sieve with a dispersion containing a metal precursor and prepare a multi-component catalyst:

[0109] 10 g of molecular sieve was dispersed in 100 mL of deionized water to obtain a molecular sieve dispersion, which was then placed in a 70 °C constant temperature water bath. 52.66 g of chromium nitrate was dissolved in 70 mL of deionized water, and 19.91 g of ammonium carbonate was dissolved in 94.0 mL of deionized water. Under vigorous stirring, the chromium nitrate solution and the ammonium carbonate solution were added dropwise to the above molecular sieve dispersion in a parallel stream. After precipitation, the mother liquor was aged in a 70 °C constant temperature water bath for 3 h, then filtered, washed with deionized water until neutral, and the resulting filter cake was dried overnight in a 100 °C oven, followed by calcination at 500 °C for 1 h (heating rate 2 °C / min) to obtain catalyst SSL-D2.

[0110] Comparative Example 3

[0111] (1) Preparation of molecular sieves:

[0112] 0.69 g of aluminum isopropoxide was added to a mixed solution containing 41.20 g of tetrapropylammonium hydroxide solution (25 wt%) and 29.88 g of deionized water to obtain a mixture. The mixture was stirred at room temperature for 12 h, and then 35.17 g of tetraethyl orthosilicate was added dropwise. After stirring for another 12 h, 25.35 g of urea was added to the mixture, and stirring was continued for 1 h to obtain a molecular sieve mother liquor. The molecular sieve mother liquor was transferred to a high-pressure reactor lined with polytetrafluoroethylene and hydrothermally treated in an oven at 180 °C for 48 h to obtain a dispersion containing the synthesized molecular sieve. After centrifugation and repeated washing with deionized water until the supernatant was neutral, the solid product obtained after drying was calcined at 550 °C for 5 h (heating rate 5 °C / min) to obtain the molecular sieve.

[0113] (2) Preparation of metal oxides: Chromium nitrate nonahydrate was used as the chromium source, and ammonium carbonate as the alkali source. 52.66 g of chromium nitrate was dissolved in 70 mL of deionized water; 19.91 g of ammonium carbonate was dissolved in 94 mL of deionized water. Under constant temperature water bath at 70 °C and vigorous stirring, the chromium nitrate solution and the ammonium carbonate solution were added dropwise to 20 mL of deionized water in a parallel stream. After precipitation, the mother liquor was aged in a constant temperature water bath at 70 °C for 3 h, then filtered and washed with deionized water until neutral, dried, and then calcined at 500 °C for 1 h (heating rate 2 °C / min) to obtain the metal oxides.

[0114] (3) Mixing molecular sieves with metal oxides

[0115] The molecular sieve obtained in step (1) and the metal oxide obtained in step (2) are ground and mixed in a mortar for 1 minute at a mass ratio of 1:1 to obtain catalyst SSL-D3.

[0116] Comparative Example 4

[0117] (1) Preparation of metal oxides:

[0118] Chromium nitrate nonahydrate was used as the chromium source, and ammonium carbonate as the alkali source. 52.66 g of chromium nitrate was dissolved in 70 mL of deionized water; 19.91 g of ammonium carbonate was dissolved in 94 mL of deionized water. The chromium nitrate solution and the ammonium carbonate solution were added dropwise to 20 mL of deionized water in a constant temperature water bath at 70 °C with vigorous stirring. After precipitation, the mother liquor was aged in a constant temperature water bath at 70 °C for 3 h, then filtered and washed with deionized water until neutral, dried, and then calcined at 500 °C for 1 h (heating rate 2 °C / min) to obtain the metal oxide.

[0119] (2) Preparation of a dispersion containing molecular sieve mother liquor:

[0120] 0.69 g of aluminum isopropoxide was added to a mixed solution containing 41.20 g of tetrapropylammonium hydroxide solution (25 wt%) and 29.88 g of deionized water to obtain a mixture. The mixture was stirred at room temperature for 12 h, and then 35.17 g of tetraethyl orthosilicate was added dropwise. After stirring for another 12 h, 25.35 g of urea was added to the mixture, and stirring was continued for 1 h to obtain a dispersion containing molecular sieve mother liquor.

[0121] (3) Mix the metal oxide with a dispersion containing molecular sieve mother liquor and prepare a multi-component catalyst:

[0122] 10g of the metal oxide obtained in step (1) was dispersed in 100mL of deionized water to obtain a dispersion of the metal oxide. Under vigorous stirring, 132.28g of the dispersion containing the molecular sieve mother liquor was added dropwise to the above metal oxide dispersion. After mixing, hydrothermal treatment was performed at 180℃ for 48 hours. The mixture was then filtered, washed with deionized water until neutral, and the resulting filter cake was dried overnight in a 100℃ oven, followed by calcination at 550℃ for 5 hours (heating rate 5℃ / min) to obtain catalyst SSL-D4.

[0123] [Test Example]

[0124] The performance of the catalysts in Examples 1-8 and Comparative Examples 1-4 was evaluated. The evaluation methods for the catalysts are as follows:

[0125] Weigh 1.5g of catalyst, crush it to 20-40 mesh, and pack it into the reactor. The reaction is carried out at a temperature of 395℃, a pressure of 4.0MPa, a feed gas H2 / CO ratio of 1.0, and a volumetric hourly space velocity (VHSV) of 2000h⁻¹. -1 Catalyst evaluation was conducted under the following conditions. The catalyst was pretreated with H2 at 395℃ for 2 hours before the reaction. The feed gas was H2 / CO / N2, and the products were analyzed online by gas chromatography, with N2 as an internal standard for quantitative analysis. The products were separated using a three-column system. One column was a Hayesep-Q packed column, and the separated products were detected by a thermal conductivity detector to identify hydrogen, nitrogen, carbon monoxide, carbon dioxide, methane, etc. A two-dimensional center-cutting technique was used to cut aliphatic and aromatic hydrocarbons, which were detected by two separate flame ionization detectors. One column was an HP-PLOT Al2O3 capillary column, and the products were detected by the flame ionization detector to identify aliphatic hydrocarbons such as methane, ethane, ethylene, propane, propylene, butane, and butene. The other column was a DB-WAXetr capillary column, and the products were detected by the flame ionization detector to identify benzene, toluene, xylene, and C. 9+ Aromatic products such as aromatics. The results for CO conversion, aromatic selectivity, and C6-C8 aromatic selectivity are shown in Table 1. (See Table 1 for results.)

[0126] Table 1

[0127]

[0128] pass Figures 1 to 4 It can be seen that the catalyst prepared by the method of the present invention ( Figures 1 to 3 Compared to the catalyst prepared by the method in Comparative Example 1 ( Figure 4 The catalyst of the present invention has small and uniformly distributed particle size components. 60%, preferably 80%, of the molecular sieve has metal oxides distributed on its outer surface.

[0129] As can be seen from Table 1, the catalyst prepared by the method of the present invention has the advantages of high CO feed conversion rate and high selectivity of aromatic / light hydrocarbon products when applied to the syngas to olefin / aromatic reaction.

[0130] The above description is merely a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, based on the technical teachings provided by the present invention and as common knowledge in the field, other equivalent modifications and improvements can be made, and these should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a multi-component catalyst, comprising: The dispersion containing the metal precursor is mixed with the dispersion containing the synthetic molecular sieve, and then subjected to hydrothermal treatment and / or aging treatment, washing, drying and calcination in sequence. Alternatively, the dispersion containing metal precipitates is mixed with the dispersion containing molecular sieve mother liquor, and then subjected to hydrothermal treatment and / or aging treatment, washing, drying and calcination in sequence. The method for preparing the dispersion containing the synthetic molecular sieve includes: mixing a silicon source, an aluminum source, a template agent, an optional ammonium auxiliaries and / or a first alkali source to obtain a molecular sieve mother liquor, and then performing hydrothermal crystallization treatment. The method for preparing the dispersion containing the metal precipitate includes: mixing the metal precursor with a second alkali source and aging it.

2. The preparation method according to claim 1, characterized in that, The method for preparing the dispersion containing the synthetic molecular sieve includes washing after hydrothermal crystallization treatment.

3. The preparation method according to claim 1 or 2, characterized in that, The weight ratio of the metal precursor to the synthetic molecular sieve is 0.02 to 50:1, wherein the metal precursor is calculated based on the metal oxide in the prepared multi-component catalyst, and the synthetic molecular sieve is calculated based on the molecular sieve in the prepared multi-component catalyst.

4. The preparation method according to claim 3, characterized in that, The weight ratio of the metal precursor to the synthesized molecular sieve is 0.1 to 10:

1.

5. The preparation method according to claim 1 or 2, characterized in that, The method for preparing the dispersion containing the metal precipitate includes washing after aging.

6. The preparation method according to claim 1 or 2, characterized in that, The weight ratio of metal precipitate to molecular sieve mother liquor is 0.02~50:1; wherein, the metal precipitate is calculated based on the metal oxides in the prepared multi-component catalyst, and the molecular sieve mother liquor is calculated based on the molecular sieves in the prepared multi-component catalyst.

7. The preparation method according to claim 6, characterized in that, The weight ratio of metal precipitate to molecular sieve mother liquor is 0.1~10:

1.

8. The preparation method according to claim 1 or 2, characterized in that, The crystallization conditions include: a crystallization temperature of 100~180℃ and a crystallization time of 12~100 hours.

9. The preparation method according to claim 8, characterized in that, The crystallization conditions include: a crystallization temperature of 105~170℃; and / or a crystallization time of 24~96 hours.

10. The preparation method according to claim 1 or 2, characterized in that, The aging conditions include: pH value of 7-11; aging temperature of 40-100℃; and aging time of 2-72 hours.

11. The preparation method according to claim 10, characterized in that, The aging conditions include: a pH value of 7 to 9; and / or an aging temperature of 50 to 80°C; and / or an aging time of 4 to 24 hours.

12. The multi-component catalyst obtained by the preparation method according to any one of claims 1-11.

13. The multi-component catalyst according to claim 12, characterized in that, The metal oxides are uniformly distributed on the outer surface of the molecular sieve.

14. The multi-component catalyst according to claim 13, characterized in that, 60% of the outer surface of the molecular sieve is covered with metal oxides.

15. The multi-component catalyst according to claim 13, characterized in that, 80% of the outer surface of the molecular sieve is covered with metal oxides.

16. A method for converting syngas into aromatics and / or light hydrocarbons, comprising: Using syngas as raw material, the raw material is reacted with a multi-component catalyst obtained by the preparation method according to any one of claims 1-11 or a multi-component catalyst according to any one of claims 12-15 to obtain a stream containing aromatics and / or light hydrocarbons.

17. The method according to claim 16, characterized in that, In the synthesis gas, the H2 / CO molar ratio is 0.3~4; and / or, The reaction conditions include: a reaction temperature of 320~480℃; and / or a reaction pressure of 0.6~9.5MPa; and / or a volume hourly space velocity of 1200~18000h⁻¹. -1 .

18. The method according to claim 17, characterized in that, In the synthesis gas, the H2 / CO molar ratio is 0.5~2.

Images