Catalyst for preparing light aromatic hydrocarbon from synthesis gas through one-step method and preparation method

Abstract

The invention discloses a catalyst for preparing light aromatic hydrocarbon from synthesis gas through a one-step method and a preparation method, and belongs to the technical field of synthesis gas catalytic conversion, the catalyst is composed of ternary spinel metal oxides and a P-modified H-ZSM-5 molecular sieve, and the ternary spinel metal oxides comprise ZnAlGaOx, ZnMgGaOx, ZnCrGaOx, ZnCrAlOx, ZnCrFeOx, ZnCrYOx and ZnAlFeOx. The catalyst shows high CO conversion rate (more than 40%) and high light aromatic hydrocarbon selectivity (more than 70%) in the reaction of preparing aromatic hydrocarbon from synthesis gas, the proportion of light aromatic hydrocarbon in total aromatic hydrocarbon is more than 80%, and methane selectivity is low (less than 3%). The method is simple in process and easy for large-scale production. The problem that the CO conversion rate and the aromatic hydrocarbon selectivity of a traditional catalyst are difficult to consider at the same time is solved, and the catalyst has remarkable economic benefits and application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of catalytic conversion of synthesis gas, and in particular to a catalyst for preparing light aromatic hydrocarbons from synthesis gas in one step and a preparation method thereof. Background Art

[0002] Aromatics is one of the important bulk chemicals, and its demand accounts for about one-third of the petrochemical market. Light aromatics such as benzene, toluene, xylene, and trimethylbenzene are important basic organic raw materials in the chemical industry. Among them, the demand for paraxylene is large, and it is mainly used to produce terephthalic acid (PTA) and then terephthalic acid glycol ester (PET). At present, 70% of aromatics come from naphtha catalytic reforming. In recent years, the use of non-petroleum-based carbon resources to produce aromatics through catalytic conversion of synthesis gas has become a research hotspot. Converting coal into synthesis gas and then producing aromatics through synthesis gas has become an important way. There are two process routes for producing aromatics from synthesis gas: indirect method and direct method. The indirect method is to first catalytically convert synthesis gas into methanol, and then generate aromatics from methanol; the direct method can use Fischer-Tropsch catalysts and bifunctional catalysts to convert synthesis gas into aromatics. The reported Fischer-Tropsch catalysts are mainly metals such as Fe, Co, and Ru, which have the characteristics of high CO conversion rate, but the aromatics selectivity is not higher than 15%.

[0003] Bifunctional catalysts are mainly composed of Zr-based, Cr-based and other metal oxides and zeolite molecular sieves, and have the characteristics of high aromatics selectivity, but the CO conversion rate is relatively low, and the proportion of light aromatics in aromatics is not high. For example, Chinese patent CN106540740A discloses a composite catalyst of Zr-based oxide and zeolite molecular sieve for synthesis gas to aromatics. The total aromatics selectivity of the catalyst system is 80%, but the CO conversion rate is only 20%. Chinese patent CN111420701A discloses a catalyst containing a CoMn spinel structure oxide composite zeolite molecular sieve. In the synthesis gas to aromatics reaction, the CO conversion rate of the catalyst system can reach 30%~50%, but the total aromatics selectivity is 40%~60%, and the proportion of light aromatics is no more than 70%. In addition, Chinese patents CN117920331A, CN118807822A, and CN117772181A all disclose a new bifunctional catalyst system for use in the production of aromatics from syngas. From the data, the above-mentioned situation also exists where the CO conversion rate and aromatics selectivity cannot be taken into account at the same time.

[0004] In summary, in the one-step synthesis of light aromatics from syngas, developing a bifunctional catalyst system with both high CO conversion rate and high light aromatics selectivity is one of the technical difficulties that needs to be solved urgently. Summary of the invention

[0005] The purpose of the present invention is to solve the above-mentioned problems in the prior art and to provide a catalyst and a preparation method for preparing light aromatics from synthesis gas in one step. The catalyst exhibits the characteristics of high CO conversion rate and high light aromatics selectivity in the synthesis gas to aromatics reaction and has good application prospects.

[0006] In order to achieve the above object, the present invention adopts the following technical scheme:

[0007] A method for preparing a catalyst for preparing light aromatics from synthesis gas in one step, comprising the following steps:

[0008] 1) preparing a ternary spinel metal oxide; the ternary spinel metal oxide comprises ZnAlGaOx, ZnMgGaOx, ZnCrGaOx, ZnCrAlOx, ZnCrFeOx, ZnCrYOx, and ZnAlFeOx, and the molar ratio of each metal element is 1:1:1;

[0009] 2) The H-ZSM-5 molecular sieve is sequentially P-modified, acid-treated, and surface-passivated to obtain a modified H-ZSM-5 molecular sieve;

[0010] 3) The ternary spinel metal oxide obtained in step 1) and the modified H-ZSM-5 molecular sieve obtained in step 2) are mixed to obtain the catalyst, wherein the mass ratio of the ternary spinel metal oxide to the modified H-ZSM-5 molecular sieve is (0.2-1.0): 1.

[0011] In the present invention, step 1) comprises the following steps:

[0012] 1.1) Select the corresponding metal nitrate according to the metal ratio to prepare an aqueous solution, and stir evenly to obtain solution A;

[0013] 1.2) Add the template to solution A to obtain mixed solution B;

[0014] 1.3) The mixed solution B is stirred in a water bath, evaporated to dryness, ground, and calcined to obtain the ternary spinel metal oxide.

[0015] The template comprises at least one of carbon black, BP2000, polystyrene microspheres, and carbon nanotubes, and the mass ratio of the template to the total metal nitrate is (1-5):1.

[0016] In the H-ZSM-5 molecular sieve, the molar ratio of Si element to Al element is (10~400):1.

[0017] The P modification comprises the following steps: preparing a molecular sieve slurry by mixing H-ZSM-5 molecular sieve with water, and then adding (NH 4 ) 2 HPO 4After stirring and ultrasonic vibration, the mixed solution is filtered to neutrality, dried and calcined. Furthermore, the weight ratio of molecular sieve to water is 1: (2~20); the added (NH 4 ) 2 HPO 4 The P content in the H-ZSM-5 molecular sieve is 0.1%~10% by weight.

[0018] The acid treatment comprises the following steps: putting the P-modified molecular sieve into a solution prepared by a macromolecular organic acid and water, heating and stirring in a water bath, filtering to neutrality, drying and then roasting. Furthermore, the mass ratio of water, macromolecular organic acid and P-modified molecular sieve is (10-50): (0.05-0.5): 1; the macromolecular organic acid comprises at least one of citric acid, p-toluenesulfonic acid, ammonium hexafluorosilicate, benzoic acid and salicylic acid.

[0019] The surface passivation comprises the following steps: putting the acid-treated molecular sieve into an organic solvent, adding a surface passivator to the organic solvent, stirring in a water bath, evaporating to dryness, grinding, and roasting. Further, the mass ratio of the organic solvent, the surface passivator, and the acid-treated molecular sieve is (5-50): (0.05-0.5): 1; the organic solvent comprises at least one of n-hexane, cyclohexane, n-heptane, cycloheptane, n-octane, and cyclooctane; the surface passivator comprises at least one of phenylmethyl silicone oil, ethyl orthosilicate, polydimethylsiloxane, triisopropyloxysilane, and hexamethyldisilazane.

[0020] In the above steps, the calcination temperature is 400~600 ℃, and the calcination time is 4~8 h.

[0021] The invention discloses an application of a catalyst for preparing light aromatics from synthesis gas in a one-step process, which is used for preparing light aromatics from synthesis gas in a one-step process.

[0022] Specifically, the conversion reaction is carried out on a fixed bed or a moving bed using synthesis gas as a reaction raw material; the synthesis gas is H 2 Mixed gas with CO, H 2 / CO ratio is 0.5~5.0; synthesis gas pressure is 3~8 MPa, reaction temperature is 300~600 ℃, space velocity is 500~10000 The product is diverted from the insulation system to the gas chromatography online detection and analysis.

[0023] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0024] 1. The present invention provides a novel one-step synthesis gas catalyst for preparing light aromatics. The catalyst has ternary spinel metal oxides and P-modified H-ZSM-5 molecular sieve as active components, and the H-ZSM-5 molecular sieve needs to be P-modified, acid-treated and surface passivated.

[0025] 2. The prepared catalyst has excellent performance. Under optimized conditions, the CO conversion rate is high (>40%), the methane selectivity is low (<3%), the aromatics selectivity is high (>70%), and the proportion of light aromatics in the total aromatics is high (>80%). It takes into account both the CO conversion rate and the aromatics selectivity, and the economic benefits are significantly improved.

[0026] 3. The present invention performs P modification, acid treatment and surface passivation treatment on H-ZSM-5 zeolite molecular sieve, thereby reducing the generation of heavy aromatics and improving the selectivity of light aromatics.

[0027] 4. The catalyst production process of the present invention is simple, easy to repeat, and easy to scale up for production. DETAILED DESCRIPTION

[0028] The present invention is described in detail below in conjunction with embodiments and comparative examples, so as to facilitate understanding of the present invention by persons skilled in the art. It is necessary to point out that the embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Non-essential improvements and adjustments made to the present invention by persons skilled in the art according to the above-mentioned invention content should still fall within the scope of protection of the present invention.

[0029] Example 1

[0030] Synthesis of ternary spinel metal oxides: Weigh 5 g zinc nitrate hexahydrate, 6.3 g aluminum nitrate nonahydrate, and 4.3 g gallium nitrate nonahydrate and dissolve them in 100 mL pure water. Slowly add 23.4 g BP2000 at room temperature and stir in a water bath. Then heat to 80 ℃ until the mixed solution is evaporated to dryness; the evaporated material is ground into powder and placed in a static air muffle furnace at 2 The temperature was raised to 450 ℃ at a heating rate of ℃ / min and calcined for 5 h to obtain a ZnAlGa ternary spinel metal oxide.

[0031] In this example, commercial ZSM-5 molecular sieve is treated by a common ammonium chloride treatment method to obtain H-ZSM-5.

[0032] The preparation of P-modified H-ZSM-5 molecular sieve comprises the following steps:

[0033] 1. P modification: Weigh 10 g of H-ZSM-5 molecular sieve with a silicon-aluminum ratio of 100, mix it in 80 g of pure water, and stir it evenly at room temperature. The mixture is first crushed with a crusher and then ultrasonically vibrated for 1 h to make a molecular sieve slurry. While the slurry is being stirred, slowly add 8.5283 g of (NH 4 ) 2 HPO 4 The mixture was stirred for 4 h and then ultrasonically vibrated for 2 h, then filtered until the washing liquid was neutral. The washed product was heated at 120 After drying at ℃ for 6 h, place in a static air muffle furnace and The heating rate was increased to 550℃ / min. ℃ calcined for 5 h.

[0034] 2. Acid treatment: Take 8 g of the above calcined product and put it into a solution prepared by 200 g of pure water and 3.2 g of ammonium hexafluorosilicate. After stirring in a 50 °C water bath for 4 h, the mixed solution is filtered until the cleaning liquid is neutral. The washed product is dried at 120 °C for 6 h and then placed in a static air muffle furnace. The temperature is increased to 550 °C at a heating rate of 1 °C / min and calcined for 5 h.

[0035] 3. Surface passivation treatment: Take 6 g of the above calcined product and mix it with 200 g of n-hexane, slowly add 2 g of benzyl silicone oil under stirring, stir and evaporate to dryness in a 50 °C water bath, grind the evaporated product into powder, place it in a static air muffle furnace, and heat it at 2 The temperature was raised to 550 °C at a heating rate of 1 °C / min and calcined for 5 h. The obtained product was P-modified H-ZSM-5 molecular sieve.

[0036] Preparation of catalyst and evaluation of its activity: Weigh the prepared ZnAlGa ternary spinel metal oxide and P-modified H-ZSM-5 molecular sieve in a weight ratio of 1:2, grind and mix them evenly in a mortar, press them into tablets, and then crush them into 30-60 mesh particles to obtain catalyst 1#. The catalytic performance of catalyst 1# was evaluated using a fixed bed reactor, and the reactor was lined with an 8 mm quartz tube. Weigh 1 g of catalyst 1# and firstly precipitate it under normal pressure and 20% H 2 +Ar atmosphere, the temperature was raised to 350 °C at a rate of 1 °C / min and maintained for 2 h; then the synthesis gas (H 2 / CO=2.0) to 5.0 MPa, the temperature was adjusted to 410 °C, and the flow rate of the synthesis gas was adjusted to a reaction space velocity of 3000 The product is diverted from the insulation system to the gas chromatography online detection and analysis.

[0037] Example 2

[0038] Synthesis of ternary spinel metal oxides: Weigh 5 g zinc nitrate hexahydrate, 6.3 g aluminum nitrate nonahydrate, and 6.725 g chromium nitrate nonahydrate and dissolve them in 100 mL pure water. Slowly add 20 g carbon black and 12.445 g carbon nanotubes at room temperature and stir in a water bath. Then heat to 80 ℃ until the mixed liquid is evaporated to dryness; the evaporated material is ground into powder, placed in a static muffle furnace, and heated to 450 ℃ at a heating rate of 2 ℃ / min and calcined for 5 h. The obtained product is ZnAlCr ternary spinel metal oxide.

[0039] Preparation of P-modified H-ZSM-5 molecular sieve: consistent with Example 1.

[0040] Preparation of catalyst and evaluation of its activity: Catalyst 2# was prepared using the ZnAlCr ternary spinel metal oxide prepared in Example 2. Other preparation and evaluation conditions were consistent with those in Example 1.

[0041] Example 3

[0042] Synthesis of ternary spinel metal oxides: 5 g zinc nitrate hexahydrate, 6.3 g aluminum nitrate nonahydrate, and 6.8 g ferric nitrate nonahydrate were weighed and dissolved in 100 mL pure water. 25 g polystyrene microspheres and 14.82 g BP2000 were slowly added at room temperature and stirred in a water bath. The mixture was then heated to 80 °C until it was evaporated to dryness. The evaporated material was ground into powder and placed in a static muffle furnace at 2 The temperature was raised to 450 ℃ at a heating rate of ℃ / min and calcined for 5 h to obtain ZnAlFe ternary spinel metal oxide.

[0043] Preparation of P-modified H-ZSM-5 molecular sieve: consistent with Example 1.

[0044] Preparation of catalyst and evaluation of its activity: Weigh the prepared ZnAlFe ternary spinel metal oxide and P-modified H-ZSM-5 molecular sieve in a weight ratio of 1:3, grind and mix them evenly in a mortar, press them into tablets, and then crush them into 30-60 mesh particles to obtain catalyst 3#. The catalytic performance of catalyst 3# was evaluated using a fixed bed reactor with an 8 mm quartz tube lined inside the reactor. Weigh 1 g of catalyst 3# and firstly precipitate it under normal pressure and 20% H 2 +Ar atmosphere, the temperature was raised to 350 °C at a rate of 1 °C / min and maintained for 2 h; then the synthesis gas (H 2 / CO=2.0) to 5.0 MPa, the temperature was adjusted to 410 °C, and the flow rate of the synthesis gas was adjusted to make the reaction space velocity The product is diverted from the insulation system to the gas chromatography online detection and analysis.

[0045] Example 4

[0046] Synthesis of ternary spinel metal oxide: consistent with Example 3.

[0047] The preparation of P-modified H-ZSM-5 molecular sieve comprises the following steps:

[0048] 1. P modification: Weigh 10 g of H-ZSM-5 molecular sieve with a silicon-aluminum ratio of 100, mix it in 80 g of pure water, and stir it evenly at room temperature. The mixture is first crushed with a crusher and then ultrasonically vibrated for 1 h to make a molecular sieve slurry. While the slurry is being stirred, slowly add 21.3206 g of (NH 4 ) 2 HPO 4 The mixed solution was stirred for 4 h and then ultrasonically vibrated for 2 h, then filtered until the cleaning solution was neutral. The washed product was dried at 120 °C for 6 h and then placed in a static air muffle furnace and heated to 550 °C at a heating rate of 1 °C / min for calcination for 5 h.

[0049] 2. Acid treatment and surface passivation treatment: the same as in Example 1.

[0050] Preparation of catalyst and evaluation of its activity: Catalyst #4 was prepared using the P-modified H-ZSM-5 molecular sieve prepared in Example 4 and ternary spinel metal oxide. Other preparation and evaluation conditions were consistent with those in Example 3.

[0051] Example 5

[0052] Synthesis of ternary spinel metal oxide: consistent with Example 3.

[0053] The preparation of P-modified H-ZSM-5 molecular sieve comprises the following steps:

[0054] 1. P modification: Weigh 10 g of H-ZSM-5 molecular sieve with a silicon-aluminum ratio of 100, mix it in 80 g of pure water, and stir it evenly at room temperature. The mixture is first crushed with a crusher and then ultrasonically vibrated for 1 h to make a molecular sieve slurry. While the slurry is being stirred, slowly add 34.113 g of (NH 4 ) 2 HPO 4 The mixed solution was stirred for 4 h and then ultrasonically vibrated for 2 h, then filtered until the cleaning solution was neutral. The washed product was dried at 120 °C for 6 h and then placed in a static air muffle furnace and heated to 550 °C at a heating rate of 1 °C / min for calcination for 5 h.

[0055] 2. Acid treatment and surface passivation treatment: the same as in Example 1.

[0056] Preparation of catalyst and evaluation of its activity: Catalyst #5 was prepared using the P-modified H-ZSM-5 molecular sieve prepared in Example 5 and ternary spinel metal oxide. Other preparation and evaluation conditions were consistent with those in Example 3.

[0057] Example 6

[0058] Synthesis of ternary spinel metal oxide: consistent with Example 3.

[0059] The preparation of P-modified H-ZSM-5 molecular sieve comprises the following steps:

[0060] 1. P modification: the same as in Example 1.

[0061] 2. Acid treatment: 8 g of the calcined product was added to a solution of 200 g pure water, 1.8 g citric acid and 0.5 g p-toluenesulfonic acid. After stirring for 4 h in a 50 °C water bath, the mixture was filtered until the washing liquid was neutral. The washed product was heated at 120 °C for 12 hours. After drying at ℃ for 6 h, place in a static air muffle furnace and The temperature was increased at a heating rate of ℃ / min to 550 ℃ and calcined for 5 h.

[0062] 3. Surface passivation treatment: the same as in Example 1.

[0063] Preparation of catalyst and evaluation of its activity: Catalyst #6 was prepared using the P-modified H-ZSM-5 molecular sieve prepared in Example 6 and ternary spinel metal oxide. Other preparation and evaluation conditions were consistent with those in Example 3.

[0064] Example 7

[0065] Synthesis of ternary spinel metal oxide: consistent with Example 3.

[0066] The preparation of P-modified H-ZSM-5 molecular sieve comprises the following steps:

[0067] 1. P modification and acid treatment: consistent with Example 1

[0068] 2. Surface passivation treatment: 6 g of the calcined product was added to a mixture of 100 g of n-heptane and 50 g of cycloheptane, and 0.9 g of hexamethyldisilazane and 1.2 g of ethyl orthosilicate were slowly added under stirring. The mixture was evaporated to dryness under stirring in a 50 °C water bath. The evaporated product was ground into powder and placed in a static air muffle furnace at 2 The temperature was raised to 550 °C at a heating rate of 1 °C / min and calcined for 5 h. The obtained product was P-modified H-ZSM-5 molecular sieve.

[0069] Preparation of catalyst and evaluation of its activity: Catalyst #7 was prepared using the P-modified H-ZSM-5 molecular sieve prepared in Example 7 and ternary spinel metal oxide. Other preparation and evaluation conditions were consistent with those in Example 3.

[0070] Example 8

[0071] Synthesis of ternary spinel metal oxide: consistent with Example 3.

[0072] Preparation of P-modified H-ZSM-5 molecular sieve: The silicon-aluminum ratio of the H-ZSM-5 molecular sieve is 200, and the rest of the treatment method is consistent with Example 1.

[0073] Preparation of catalyst and evaluation of its activity: Catalyst #8 was prepared using the P-modified H-ZSM-5 molecular sieve prepared in Example 8 and ternary spinel metal oxide. Other preparation and evaluation conditions were consistent with those in Example 3.

[0074] Example 9

[0075] Synthesis of ternary spinel metal oxide: consistent with Example 3.

[0076] Preparation of P-modified H-ZSM-5 molecular sieve: The silicon-aluminum ratio of the H-ZSM-5 molecular sieve is 300, and the rest of the treatment method is consistent with Example 1.

[0077] Preparation of catalyst and evaluation of its activity: Catalyst 9# was prepared using the P-modified H-ZSM-5 molecular sieve prepared in Example 9 and ternary spinel metal oxide. Other preparation and evaluation conditions were consistent with those in Example 3.

[0078] Comparative Example 1

[0079] Synthesis of ternary spinel metal oxide: consistent with Example 3.

[0080] Molecular sieve: H-ZSM-5 molecular sieve with a silicon-aluminum ratio of 100, without other post-treatment.

[0081] Preparation of catalyst and evaluation of its activity: Comparative catalyst #1 was prepared using H-ZSM-5 molecular sieve with a silicon-aluminum ratio of 100 without post-treatment and ternary spinel metal oxide. Other preparation and evaluation conditions were consistent with those in Example 3.

[0082] Comparative Example 2

[0083] Synthesis of ternary spinel metal oxide: consistent with Example 3.

[0084] Molecular sieve: H-ZSM-5 molecular sieve with a silicon-aluminum ratio of 100, without P modification, but subjected to acid treatment and surface passivation treatment as in Example 1.

[0085] Preparation of catalyst and evaluation of its activity: Comparative catalyst #2 was prepared using the H-ZSM-5 molecular sieve prepared in Comparative Example 2 and ternary spinel metal oxide. Other preparation and evaluation conditions were consistent with those in Example 3.

[0086] Comparative Example 3

[0087] Synthesis of ternary spinel metal oxide: consistent with Example 3.

[0088] Molecular sieve: H-ZSM-5 molecular sieve with a silicon-aluminum ratio of 100, without acid treatment, but P modification and surface passivation treatment are carried out normally in the manner of Example 1.

[0089] Preparation of catalyst and evaluation of its activity: Comparative catalyst #3 was prepared using the H-ZSM-5 molecular sieve prepared in Comparative Example 3 and ternary spinel metal oxide. Other preparation and evaluation conditions were consistent with those in Example 3.

[0090] Comparative Example 4

[0091] Synthesis of ternary spinel metal oxide: consistent with Example 3.

[0092] Molecular sieve: H-ZSM-5 molecular sieve with a silicon-aluminum ratio of 100, without surface passivation treatment, but P modification and acid treatment are normally carried out in the manner of Example 1.

[0093] Preparation of catalyst and evaluation of its activity: Comparative catalyst #4 was prepared using the H-ZSM-5 molecular sieve prepared in Comparative Example 4 and ternary spinel metal oxide. Other preparation and evaluation conditions were consistent with those in Example 3.

[0094] The above catalyst evaluation results are listed in Table 1.

[0095] Table 1 Catalyst performance evaluation results

[0096]

[0097] Note: ARO is total aromatics; BTX+Me 3 PH is benzene, toluene, xylene and trimethylbenzene, which are light aromatics; Me≥ 4 Ph is a heavy aromatic hydrocarbon with ≥4 carbon atoms in the benzene ring branch; C 2-4 C 2 -C 4 of hydrocarbon organic products.

[0098] By comparing Examples 1 to 9, it can be seen that by changing the composition of the ternary spinel metal oxide, adjusting the preparation method of the P-modified H-ZSM-5 molecular sieve, etc., in the catalytic reaction of directly preparing light aromatics from synthesis gas, the CO conversion rate is achieved to be greater than 40%, the selectivity of aromatics accounts for more than 70% of the total hydrocarbons, BTX plus trimethylbenzene accounts for 80% to 85% of the total aromatics, and the by-product methane is less than 3%. This shows that the catalytic performance of the catalytic system is excellent as a whole, the preparation process has strong adaptability to changes in parameters, and it is easy to scale up production in industry.

[0099] By comparing the catalytic reaction data of the examples and the comparative examples, it can be seen that the post-treatment process of the H-ZSM-5 molecular sieve plays a pivotal role in the catalyst system. Taking the comparative example 1 without the three post-treatment processes of the present invention as an example, in the catalytic reaction, the CO conversion rate is much lower than that of the reference example 3, and the total aromatics selectivity does not exceed 50%, and the proportion of light aromatics in the total aromatics is only 38.0%.

[0100] By analyzing the catalytic reaction data of comparative examples 1 to 4, it can be seen that the post-treatment process of P modification of H-ZSM-5 molecular sieve is particularly outstanding in improving the selectivity of total aromatics and the proportion of light aromatics in total aromatics, indicating that P modification plays a key role in the catalyst system. Further acid treatment and surface passivation treatment of H-ZSM-5 molecular sieve can further improve the selectivity of total aromatics and increase the proportion of light aromatics in total aromatics. Each link complements each other and is indispensable.

[0101] For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, without having to go through creative labor. Therefore, simple improvements made to the present invention by those skilled in the art based on the disclosure of the present invention should be within the protection scope of the present invention. The above embodiments are preferred embodiments of the present invention, and all processes similar to the present invention and equivalent changes made should belong to the protection scope of the present invention.

Claims

1. A method for preparing a catalyst for preparing light aromatics from synthesis gas in one step, characterized in that: The following steps are involved: 1) preparing a ternary spinel metal oxide; the ternary spinel metal oxide comprises , , , , , , , the molar ratio of each metal element is 1:1:1; 2) The H-ZSM-5 molecular sieve is sequentially P-modified, acid-treated, and surface-passivated to obtain a modified H-ZSM-5 molecular sieve; 3) The ternary spinel metal oxide obtained in step 1) and the modified H-ZSM-5 molecular sieve obtained in step 2) are mixed to obtain the catalyst, wherein the mass ratio of the ternary spinel metal oxide to the modified H-ZSM-5 molecular sieve is (0.2-1.0):

1.

2. The method for preparing a catalyst for preparing light aromatic hydrocarbons from synthesis gas in one step as claimed in claim 1, characterized in that: Step 1) includes the following steps: 1.1) Select the corresponding metal nitrate according to the metal ratio to prepare an aqueous solution, and stir evenly to obtain solution A; 1.2) Add the template to solution A to obtain mixed solution B; 1.3) The mixed solution B is stirred in a water bath, evaporated to dryness, ground, and calcined to obtain the ternary spinel metal oxide.

3. The method for preparing a catalyst for preparing light aromatic hydrocarbons from synthesis gas in one step as claimed in claim 2, characterized in that: The template comprises at least one of carbon black, BP2000, polystyrene microspheres, and carbon nanotubes, and the mass ratio of the template to the total metal nitrate is (1-5):

1.

4. The method for preparing a catalyst for preparing light aromatic hydrocarbons from synthesis gas in one step as claimed in claim 1, characterized in that: In the H-ZSM-5 molecular sieve, the molar ratio of Si element to Al element is (10~400):

1.

5. The method for preparing a catalyst for preparing light aromatic hydrocarbons from synthesis gas in one step as claimed in claim 1, characterized in that: The P modification comprises the following steps: preparing a molecular sieve slurry by mixing H-ZSM-5 molecular sieve with water, and then adding , first stirred and then ultrasonically vibrated, the mixed solution was filtered to neutrality, dried and roasted; The P content in the H-ZSM-5 molecular sieve is 0.1%~10% by weight.

6. The method for preparing a catalyst for preparing light aromatics from synthesis gas in one step according to claim 1, characterized in that: The acid treatment comprises the following steps: putting the P-modified molecular sieve into a solution prepared by a macromolecular organic acid and water, heating and stirring in a water bath, filtering to neutrality, drying and then roasting; the mass ratio of water, macromolecular organic acid and P-modified molecular sieve is (10~50): (0.05~0.5): 1; the macromolecular organic acid comprises at least one of citric acid, p-toluenesulfonic acid, ammonium hexafluorosilicate, benzoic acid and salicylic acid.

7. The method for preparing a catalyst for preparing light aromatic hydrocarbons from synthesis gas in one step as claimed in claim 1, characterized in that: The surface passivation comprises the following steps: putting the acid-treated molecular sieve into an organic solvent, adding a surface passivator into the organic solvent, stirring in a water bath, evaporating to dryness, grinding and roasting; the mass ratio of the organic solvent, the surface passivator and the acid-treated molecular sieve is (5-50): (0.05-0.5): 1; the organic solvent comprises at least one of n-hexane, cyclohexane, n-heptane, cycloheptane, n-octane and cyclooctane; the surface passivator comprises at least one of phenylmethyl silicone oil, tetraethyl orthosilicate, polydimethylsiloxane, triisopropylsilane and hexamethyldisilazane.

8. A catalyst for preparing light aromatics from synthesis gas in one step, characterized by: Prepared by the preparation method according to any one of claims 1 to 7.

9. The use of a catalyst for preparing light aromatics from synthesis gas in one step according to claim 8, characterized in that: Used for one-step production of light aromatics from synthesis gas.

10. The use according to claim 9, characterized in that: The synthesis gas is used as the reaction raw material, and the conversion reaction is carried out on a fixed bed or a moving bed; the synthesis gas is and of mixed gas, The ratio is 0.5~5.0; the pressure of the synthesis gas is 3~8 MPa, and the reaction temperature is 300~600 , airspeed is 500~10000 .

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