A method for directly converting syngas into liquid fuels

Abstract

The present invention belongs to the preparation of liquid fuels from syngas, and particularly relates to a method for directly converting syngas into liquid fuels. Using syngas as the reaction raw material, the conversion reaction is carried out in a fixed bed or a moving bed. The catalyst used includes Component I and Component II, and Component I and Component II are compounded together in a mechanical mixing manner; the active ingredient of Component I is a metal oxide, and Component II is a heteroatom ZSM-5 molecular sieve; the heteroatom in the heteroatom ZSM-5 molecular sieve is Fe or Ga. The reaction process of the present invention has a very high product yield and selectivity. The selectivity of the liquid fuel composed of C5-C 11 can reach 50-80%, the selectivity of aromatics in C5-C 11 is less than 40%, and at the same time, the selectivity of the by-product methane is less than 3%, having good application prospects.

Description

Technical Field

[0001] The present invention belongs to the preparation of liquid fuels from syngas, and particularly relates to a method for directly converting syngas into liquid fuels. Background Art

[0002] With the development of the economy and the improvement of living standards, the demand for liquid fuels and chemicals has increased sharply year by year.

[0003] The technical route of gasifying to obtain syngas (i.e., a mixture of CO and H2), converting syngas into methanol, and then producing gasoline from methanol via dimethyl ether has been mature and has entered industrialization. This route provides an important way for the production of liquid fuels from carbon resources such as coal, biomass, and even CO2. However, if direct conversion of syngas can be achieved without going through the routes of methanol synthesis and methanol dehydration to dimethyl ether, not only can the process flow be simplified, but also unit operations can be reduced, and investment and energy consumption can be lowered. The traditional Fischer-Tropsch route can achieve the direct conversion of syngas to liquid fuels. However, limited by its reaction mechanism, CO and H2 molecules dissociate and adsorb on the catalyst surface to generate surface C atoms and O atoms. The C atoms and O atoms react with hydrogen adsorbed on the catalyst surface to form CH x intermediates, while generating water molecules. The CH x intermediates freely polymerize on the catalyst surface to generate hydrocarbon products with different carbon atom numbers (from one to thirty, and sometimes even up to hundreds of carbon atoms). The carbon atom number distribution of the hydrocarbon products in the whole reaction is wide, and the selectivity of the target product is low. For example, the selectivity of gasoline is less than 50%. Summary of the Invention

[0004] In view of the above problems, the present invention provides a method for directly converting syngas into liquid fuels. By adjusting the products of syngas conversion to liquid fuels through a catalyst, the selectivity of gasoline in the liquid fuels is greatly improved, and the selectivity of aromatics is relatively low.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] A method for directly converting syngas into liquid fuels, using syngas as a reaction raw material, and performing a conversion reaction in a fixed bed or a moving bed. The catalyst used includes Component I and Component II, and Component I and Component II are compounded together in a mechanical mixing manner; the active ingredient of Component I is a metal oxide, and Component II is a heteroatom ZSM-5 molecular sieve.

[0007] Based on the above technical solution, the heteroatom in the heteroatom ZSM-5 molecular sieve is Fe or Ga.

[0008] Based on the above technical solution, the metal oxide is MnO x 、CrO x, Mn a Cr (1-a) O x , ZnO x , Zn a Cr (1-a) O x , Zn a Al (1-a) O x , Zn a Ga (1-a) O x , Zn a Mn b Al (1-a-b) O x , Zn a Cr b Al (1-a-b) O x , Zn a Cr b Mn (1-a-b) O x One or more of the following; wherein the value range of x is 0.7 to 3.7, the value range of a is 0 to 1, and the value range of a + b is 0 to 1; in the present invention, a, b, (1 - a), (1 - a - b), and x only represent the relative proportions of the chemical compositions of the elements in the metal oxide, and metal oxides with the same proportions are regarded as the same metal oxide;

[0009] The specific surface area of the said MnO x , ZnO x , CrO x is 1 - 100 m 2 / g; preferably the specific surface area is 50 - 100 m 2 / g;

[0010] The said Mn a Cr (1-a) O x , Zn a Cr (1-a) O x , Zn a Al (1-a) O x , Zn a Ga (1-a) O x , Zn a Mn b Al (1-a-b) O x , Zn a Cr b Al (1-a-b) O x , Zn a Cr b Mn(1-a-b) O x has a specific surface area of 5 - 250 m 2 / g, preferably a specific surface area of 50 - 250 m 2 / g.

[0011] Based on the above technical solutions, the micropore specific surface area of the heteroatom ZSM-5 molecular sieve accounts for 70% - 100% of the total specific surface area of the molecular sieve. The specific surface area is determined by N2 physical adsorption, and micropores refer to pore channels with a diameter below 2 nm.

[0012] Based on the above technical solutions, the heteroatom ZSM-5 molecular sieve has the characteristics of medium-strong acid, and the amount of medium-strong acid sites is 0.05 - 0.5 mol / kg, preferably 0.05 - 0.4 mol / kg, more preferably 0.05 - 0.3 mol / kg.

[0013] The acid strength is defined by the NH3-TPD peak, including three types of acidity: weak acid, medium-strong acid, and strong acid;

[0014] This NH3-TPD is based on the desorption peak position of NH3. The position of the desorption peak refers to the test conditions where, under standard test conditions, the ratio of the sample mass w to the carrier gas flow rate f (w / f) = 100 g·h / L and the heating rate is 10 °C / min. The TCD records the thermal conductivity signal of the desorbed NH3, plots the desorption curve, and classifies the inorganic solid into three acid strengths according to the apex of the curve peak position; weak acid refers to the acid site where the NH3 desorption temperature is less than 275 °C; medium-strong acid is the acid site where the NH3 desorption temperature is between 275 - 500 °C; strong acid is the acid site where the NH3 desorption temperature is greater than 500 °C. Using acetone as the probe molecule, 13 The C-NMR chemical shift is in the range of 210 - 220 ppm.

[0015] The molecular sieve in Component II can be self-synthesized or a commercial product, and it needs to meet the scope defined in the present invention.

[0016] Based on the above technical solutions, the weight ratio between the active ingredient in Component I and Component II is 0.1 - 20, preferably 0.3 - 5.

[0017] Based on the above technical solutions, a dispersant is further added to Component I, and the metal oxide is dispersed in the dispersant. The dispersant is one or more of SiO2, ZrO2, TiO2, Ga2O3, activated carbon, graphene, and carbon nanotubes;

[0018] Based on the above technical solutions, in Component I, the content of the dispersant is 0.05 - 90 wt%, preferably 0.05 - 25 wt%, and the rest is the metal oxide.

[0019] Based on the above technical solution, the pressure of the syngas is 0.5 - 10 MPa, preferably 1 - 8 MPa; the reaction temperature is 300 - 600 °C, preferably 320 - 450 °C; the space velocity is 300 - 12000 mL / g / h, preferably 1000 - 9000 mL / g / h; the syngas is a H2 / CO mixture, and the H2 / CO ratio is 0.2 - 3.5, preferably 0.5 - 2.5.

[0020] The beneficial effects of the present invention are as follows:

[0021] 1. Different from the traditional Fischer - Tropsch synthesis technology, the present invention uses a strategy of separating active centers. Using a bifunctional catalyst composed of a specific oxide + heteroatom ZSM - 5 zeolite can separate the CO activation and C - C coupling on two active centers, thereby breaking the limitation of product selectivity in traditional Fischer - Tropsch synthesis and obtaining high liquid fuel selectivity. Among them, the selectivity of gasoline fraction is high and is not restricted by the ASF model.

[0022] 2. The heteroatom doped in the heteroatom ZSM - 5 of the present invention is Fe or Ga, which has a weaker acid strength compared with the traditional ZSM - 5 zeolite under the condition of the same metal content. Therefore, it is beneficial to the formation of olefin components, promotes chain growth, and thus promotes the increase of the selectivity of C5 - C 11 components. At the same time, due to its relatively weaker acid strength, the formation of aromatic substances is weakened, resulting in a significant reduction in the aromatic content in the product. Therefore, liquid fuels with low aromatic content can be prepared.

[0023] 3. The selectivity of liquid fuel in the product is high. The selectivity of liquid fuel composed of C5 - C 11 can reach 50 - 80%, the selectivity of aromatics in C5 - C 11 is less than 40%, the selectivity of methane is extremely low, less than 3%, and the product can be separated without cryogenic cooling, greatly reducing the energy consumption and cost of separation, and having high application prospects.

[0024] 4. The active component metal oxide of component I in the catalyst has a relatively high specific surface area. Therefore, there are more active sites on the surface of the metal oxide, which is more conducive to the progress of the catalytic reaction.

[0025] 5. The function of component II in the catalyst is, on the one hand, to couple with component I to convert the active gas - phase intermediate generated by component I into liquid fuel, especially gasoline. Due to the role of component II in pulling the tandem reaction equilibrium, it can promote the activation and conversion of component I to syngas and thus improve the conversion rate; on the other hand, the zeolite in component II used in the present invention has a topological structure conducive to the formation of C5 - C 11 components. The introduction of heteroatoms in component II reduces the acid strength of the zeolite, thereby increasing the selectivity of C5 - C 11 components.

[0026] 6. Using Component I or Component II described in the present invention separately cannot achieve the functions of the present invention at all. For example, when Component I is used alone, the methane selectivity in the product is very high, but the conversion rate is very low. While when Component II is used alone, it can hardly activate and convert syngas. Only when Component I and Component II act synergistically can efficient syngas conversion be achieved and excellent selectivity be obtained. This is because Component I can activate syngas to generate specific active gas-phase intermediates, and the intermediates diffuse into the pores of Component II through gas phase. Due to the heteroatom ZSM-5 zeolite selected in the present invention, its 3D ten-membered ring intersecting pores and specific acidity can effectively further activate and convert the active gas-phase intermediates generated by Component I into liquid fuels. Detailed implementation manners

[0027] The present invention will be further described below through examples, but the scope of the claims of the present invention is not limited by these examples. At the same time, the examples only give some conditions for achieving this purpose, but it does not mean that these conditions must be met to achieve this purpose.

[0028] The specific surface area of the sample can be tested by the method of physical adsorption of nitrogen or argon.

[0029] The metal oxides described in the present invention can be obtained by purchasing commercially available metal oxides with high specific surface area, or can be obtained by the following several methods:

[0030] I. Preparation of Catalyst Component I

[0031] (1). Synthesis of ZnO material with high specific surface by precipitation method:

[0032] (1) Weigh 3 portions of 0.446 g (1.5 mmol) of Zn(NO3)2·6H2O in 3 containers respectively, then weigh 0.300 g (7.5 mmol), 0.480 g (12 mmol), and 0.720 g (18 mmol) of NaOH and add them to the above 3 containers in sequence. Then measure 30 ml of deionized water and add it to each of the 3 containers. Stir at 70 °C for more than 0.5 h to make the solution mix evenly, and cool it naturally to room temperature. Centrifuge the reaction solution to collect the precipitate after centrifugation, and wash it 2 times with deionized water to obtain the ZnO metal oxide precursor;

[0033] (2) Calcination: After the obtained product is dried in air, it is calcined in an atmosphere to obtain a ZnO material with a high specific surface area. The atmosphere is an inert gas, a reducing gas, or an oxidizing gas; the inert gas is one or more of N2, He, and Ar; the reducing gas is one or two of H2 and CO, and the reducing gas may also contain an inert gas; the oxidizing gas is one or more of O2, O3, and NO2, and the oxidizing gas may also contain an inert gas. The calcination temperature is 300 - 700 °C, and the time is 0.5 h - 12 h.

[0034] The purpose of calcination is to decompose the precipitated metal oxide precursor into oxide nanoparticles with a high specific surface area at high temperature, and the adsorbed species on the surface of the decomposed oxide can be cleaned by the high-temperature treatment of calcination.

[0035] The specific samples and their preparation conditions are as shown in Table 1 below. As a comparative example, ZnO#4 in the table is a commercially available ZnO single crystal with a low specific surface area.

[0036] Table 1 Preparation and Parameter Performance of ZnO Materials

[0037]

[0038] (2) Synthesis of MnO Material with High Specific Surface Area by Coprecipitation Method:

[0039] The preparation process is the same as that of ZnO#1 above, except that the Zn precursor is replaced with the corresponding Mn precursor, which can be one of manganese nitrate, manganese chloride, and manganese acetate. Here, it is manganese nitrate, and the corresponding product is defined as MnO; the specific surface area is: 23 m 2 / g.

[0040] (3) Synthesis of Cr2O3 Material with High Specific Surface Area by Coprecipitation Method:

[0041] The preparation process is the same as that of ZnO#2 above, except that the Zn precursor is replaced with the corresponding Cr precursor, which can be one of chromium nitrate, chromium chloride, and chromium acetate. Here, it is chromium nitrate, and the corresponding product is defined as Cr2O3; the specific surface area is: 92 m 2 / g.

[0042] (4) Synthesis of Mn a Cr (1-a) O x 、Zn a Cr (1-a) O x 、Zn a Al (1-a) O x 、Zn a Ga (1-a)O x 、Zn a Mn b Al (1-a-b) O x 、Zn a Cr b Al (1-a-b) O x 、Zn a Cr b Mn (1-a-b) O x

[0043] Using zinc nitrate, aluminum nitrate, chromium nitrate, manganese nitrate, and gallium nitrate as precursors, and one or more of ammonium carbonate, ammonium bicarbonate, and sodium carbonate as precipitants. The precursors are mixed with each other in water at room temperature, and then transferred to a water bath with a temperature range of 50 - 90 °C, and the precipitant is added (where the feeding ratio of the precipitant is 100 - 150% of the theoretical amount); the above mixture is aged, then taken out for washing, filtering, and drying, and the obtained solid is calcined in an air atmosphere to obtain a metal oxide with a high specific surface area. The specific samples and their preparation conditions are shown in Table 2 below.

[0044] Table 2 Preparation and Performance Parameters of Metal Oxides with High Specific Surface Area

[0045]

[0046]

[0047] (V) Metal Oxides Dispersed with Dispersants SiO2, ZrO2, TiO2, Ga2O3

[0048] Taking the preparation of dispersed ZnO as an example, commercial ZrO2 (specific surface area of about 10 m 2 / g) is pre-dispersed in water as a carrier, and then zinc nitrate is used as a raw material and mixed with a sodium hydroxide precipitant for precipitation at room temperature. The molar concentration of Zn 2+ is 0.067 M, and the molar ratio of Zn 2+ to the precipitant is 1:8; then it is aged at 60 °C for 24 hours to obtain ZnO dispersed with ZrO2 as a carrier (the contents of the dispersant in Component I are 0.1 wt%, 20 wt%, and 85 wt% in sequence). The obtained samples are calcined in air at 500 °C for 1 h, and the products are defined as Dispersed Oxides 1 - 3 in sequence, and their specific surface areas are: 148 m 2 / g, 115 m 2 / g, 127 m 2 / g.

[0049] In the same way, SiO2 (specific surface area of about 2 m 2 / g), Ga2O3 (specific surface area of about 10 m 2 / g) or TiO2 (specific surface area of about 15 m 2 / g) as the carrier-dispersed MnO oxide (the contents of the dispersant in component I are 5 wt%, 30 wt%, and 60 wt% in sequence), and the products are defined as dispersed oxides 4-6 in sequence. Their specific surface areas are: 97 m 2 / g, 64 m 2 / g, 56 m 2 / g.

[0050] In the same way, activated carbon (specific surface area of about 1000 m 2 / g), graphene (specific surface area of about 500 m 2 / g) or carbon nanotubes (specific surface area of about 300 m 2 / g) can be used as the carrier-dispersed ZnO oxide (the contents of the dispersant in component I are 5 wt%, 30 wt%, and 60 wt% in sequence), and the products are defined as dispersed oxides 7-9 in sequence. Their specific surface areas are: 177 m 2 / g, 245 m 2 / g, 307 m 2 / g.

[0051] II. Preparation of Component II Heteroatom ZSM-5

[0052] The heteroatom ZSM-5 molecular sieve has a 3D ten-membered ring intersecting pore structure.

[0053] The medium-strong acid described in the present invention can be tested by means such as the H spectrum of solid nuclear magnetic resonance, NH3-TPD, infrared, chemical titration, etc. However, the acid testing method is not limited to the above testing methods.

[0054] The molecular sieve described in the present invention can be a commercial heteroatom ZSM-5 molecular sieve with an acid density meeting the requirements of the present invention, or a self-synthesized molecular sieve. Here, the molecular sieve prepared by the hydrothermal synthesis method is taken as an example.

[0055] (I). Synthesis of heteroatom ZSM-5 molecular sieve by hydrothermal method, and the specific preparation process is as follows:

[0056] According to n(SiO2) / n(Fe2O3) = 100, n(TPAOH) / n(SiO2) = 0.4, n(H2O) / n(SiO2) = 35, n(EDTA) / n(Fe2O3) = 4.

[0057] Mix tetrapropylammonium hydroxide (TPAOH), tetraethyl orthosilicate (TEOS), iron nitrate, ethylenediaminetetraacetic acid (EDTA), and deionized water raw materials according to the above feeding ratio at room temperature and stir evenly. Then, age for 4 h at room temperature under vigorous stirring. Transfer the obtained gel to a hydrothermal reactor and crystallize by rotation at 180 °C for 4 days. After the crystallization is completed, quickly cool the reactor in a water bath to room temperature, and centrifuge and wash repeatedly until the pH of the supernatant is 7. First, dry the obtained precipitate in an oven at 70 °C for 6 h, and then transfer it to an oven at 110 °C to dry overnight. Then, calcine in air at 550 °C for 6 h to obtain the desired heteroatom ZSM-5.

[0058] By changing the types and ratios of the precursors, various heteroatom ZSM-5 molecular sieves can be obtained. Specifically, see Table 3, which are defined as fractions 1-6 in sequence. The molecular sieves described in Table 3 are all molecular sieves after being synthesized according to the feeding ratio in Table 3 and treated by the treatment steps described in step (1).

[0059] Table 3 Preparation and performance parameters of different heteroatom ZSM-5 molecular sieves

[0060]

[0061]

[0062] III. Preparation of catalyst

[0063] Add the required proportions of component I and component II into a container, and utilize the extrusion force, impact force, shearing force, frictional force, etc. generated by the high-speed movement of these materials and / or the container to achieve the purposes of separation, crushing, mixing, etc. Convert mechanical energy, thermal energy, and chemical energy by adjusting the temperature and carrier gas atmosphere, and further adjust the interaction between different components.

[0064] During the mechanical mixing process, the mixing temperature can be set at 20-100 °C, and it can be carried out in an atmosphere or directly in air. The atmosphere is selected from any of the following gases:

[0065] a) Nitrogen and / or inert gas;

[0066] b) A mixture of hydrogen and nitrogen and / or inert gas, where the volume of hydrogen in the mixture is 5-50%;

[0067] c) A mixture of CO and nitrogen and / or inert gas, where the volume of CO in the mixture is 5-20%;

[0068] d) A mixture of O2 and nitrogen and / or inert gas, where the volume of O2 in the mixture is 5-20%, and the inert gas is one or more of helium, argon, and neon.

[0069] Mechanical mixing can be carried out by one or more of mechanical stirring, ball milling, shaking table mixing, and mechanical grinding, specifically as follows:

[0070] Mechanical stirring: In a stirring tank, components I and II are mixed using a stirring rod. By controlling the stirring time (5 min - 120 min) and rate (30 - 300 revolutions per minute), the mixing degree of components I and II can be adjusted.

[0071] Ball milling: Using abrasives and catalysts to tumble at high speed in a grinding jar, which strongly impacts and rolls over the catalyst to achieve the effect of dispersing and mixing components I and II. By controlling the abrasives (the material can be stainless steel, agate, quartz. Size range: 5 mm - 15 mm) and the ratio of abrasives to the catalyst (mass ratio range: 20 - 100:1).

[0072] Shaking table mixing method: Components I and II are pre-mixed and loaded into a container; by controlling the reciprocating oscillation or circular oscillation of the shaking table, the mixing of components I and II is achieved; by adjusting the oscillation speed (range: 1 - 70 revolutions per minute) and time (range: 5 min - 120 min), uniform mixing is achieved.

[0073] Mechanical grinding method: Components I and II are pre-mixed and loaded into a container; under a certain pressure (range: 5 kg - 20 kg), through the relative movement of the grinding tool and the mixed catalyst (rate range: 30 - 300 revolutions per minute), the effect of uniform mixing is achieved.

[0074] The specific catalyst preparation and its parameter characteristics are shown in Table 5.

[0075] Table 5 Catalyst Preparation and Its Parameter Characteristics

[0076]

[0077]

[0078]

[0079] IV. Catalytic Reaction Examples

[0080] Taking the fixed-bed reaction as an example, but the catalyst is also applicable to a moving-bed reactor. The device is equipped with a gas mass flowmeter and an on-line product analysis chromatograph (the tail gas of the reactor is directly connected to the quantitative valve of the chromatograph for periodic real-time sampling and analysis).

[0081] Place 2 g of the catalyst of the present invention described above in a fixed-bed reactor, displace the air in the reactor with Ar, and then heat it to 300 °C in an H2 atmosphere. Switch to syngas (H2 / CO molar ratio = 0.2 - 3.5), the pressure of the syngas is 0.5 - 10 MPa, heat it to the reaction temperature of 300 - 600 °C, and adjust the space velocity of the reaction feed gas to 300 - 12000 ml / g / h. The product is detected and analyzed by on-line chromatography.

[0082] Changing the temperature, pressure, space velocity, and the molar ratio of H2 / CO in the syngas can change the reaction performance. Among them, the selectivity of the liquid fuel composed of C5 - C 11 can reach 50 - 80%; due to the low hydrogenation activity on the surface of the catalyst metal complex, the large generation of methane is avoided, and the methane selectivity is low. Table 6 lists the specific applications of the catalyst and their effect data. The C5 - C 11 selectivity and CH4 selectivity in the table are both their selectivities among all hydrocarbons.

[0083] Table 6 Specific applications of the catalyst and their effect data

[0084]

[0085] In Comparative Example 1, the catalyst component I is Zn 0.33 Al 0.67 O 1.33 #1, and the component II is commercially available conventional ZSM-5 with n(SiO2) / n(Al2O3) = 43.

[0086] In Comparative Example 2, the catalyst component I is Zn 0.33 Al 0.67 O 1.33 #2, and the component II is commercially available conventional ZSM-5 with n(SiO2) / n(Al2O3) = 146.

[0087] In Comparative Example 3, the catalyst component I is Zn 0.5 Al 0.25 Cr 0.25 O 1.25 , and the component II is commercially available conventional ZSM-5 with n(SiO2) / n(Al2O3) = 203.

[0088] In Comparative Example 4, the catalyst component I is Zn 0.25 Cr 0.5 Mn 0.25 O 1.5 , and the component II is commercially available conventional ZSM-5 with n(SiO2) / n(Al2O3) = 436.

[0089] The reaction results of Comparative Examples 1-4 show that when using conventional ZSM-5 molecular sieves with different aluminum element contents instead of heteroatom ZSM-5 molecular sieves and coupling them with different oxides for reaction performance evaluation, the selectivity of liquid fuels in the products is poor, and the selectivity of methane in the products is also too high, exceeding 5%. After coupling heteroatom ZSM-5 (with different Fe or Ga element contents) molecular sieves with different oxides, the selectivity of gasoline in the products is relatively high, between 50-80%, and the selectivity of aromatics in C5-C 11 is less than 40%, and at the same time, the selectivity of by-product methane is less than 3%. This shows that heteroatom ZSM-5 molecular sieves are suitable for the production of liquid fuels with low aromatic hydrocarbon content.

[0090] The catalyst component of Comparative Example 5 only contains oxides, which has a very low CO conversion rate, and the hydrocarbons in the product are mainly CH4, and there is basically no C5-C 11 component, indicating that using only the oxide component cannot achieve the effect of producing liquid fuels as described in the present invention.

[0091] The catalyst component of Comparative Example 6 only contains heteroatom ZSM-5 molecular sieves, which do not have the ability to convert CO and do not have the performance of synthesizing gasoline from syngas, indicating that using only the molecular sieve component cannot achieve the effect of producing liquid fuels as described in the present invention.

[0092] As can be seen from the above table, the type of molecular sieve, that is, different heteroatoms and their doping amounts directly affect the acid strength and acid amount of the molecular sieve, thereby further affecting the conversion rate of carbon monoxide and the selectivity of liquid fuels. Using only the oxide component or only the heteroatom ZSM-5 molecular sieve component cannot achieve the above effects.

Claims

1. A method for directly converting syngas into liquid fuels, characterized in that: Using syngas as the reaction raw material, a conversion reaction is carried out in a fixed bed or a moving bed. The catalyst used includes component I and component II, and component I and component II are compounded together in a mechanical mixing manner; the active ingredient of component I is a metal oxide, and component II is a heteroatom ZSM-5 molecular sieve; the heteroatom in the heteroatom ZSM-5 molecular sieve is Fe or Ga; The metal oxide is MnO x , CrO x , Mn a Cr (1-a) O x , ZnO x , Zn a Cr (1-a) O x , Zn a Al (1-a) O x , Zn a Ga (1-a) O x , Zn a Mn b Al (1-a-b) O x , Zn a Cr b Al (1-a-b) O x , Zn a Cr b Mn (1-a-b) O x or more than two of them, where the value range of x is 0.7 - 3.7, the value range of a is 0 - 1, and the value range of a + b is 0 - 1; The described MnO x , ZnO x , CrO x has a specific surface area of 1 - 100 m 2 / g; The Mn a Cr (1-a) O x 、Zn a Cr (1-a) O x 、Zn a Al (1-a) O x 、Zn a Ga (1-a) O x 、Zn a Mn b Al (1-a-b) O x 、Zn a Cr b Al (1-a-b) O x 、Zn a Cr b Mn (1-a-b) O x has a specific surface area of 5 - 250 m 2 / g; the heteroatom ZSM-5 molecular sieve has the characteristics of medium strong acid, and the amount of medium strong acid sites is 0.05 - 0.5 mol / kg.

2. The method according to claim 1, wherein The described MnO x , ZnO x , CrO x has a specific surface area of 50 - 100 m 2 / g; The Mn a Cr (1-a) O x 、Zn a Cr (1-a) O x 、Zn a Al (1-a) O x 、Zn a Ga (1-a) O x 、Zn a Mn b Al (1-a-b) O x 、Zn a Cr b Al (1-a-b) O x 、Zn a Cr b Mn (1-a-b) O x has a specific surface area of 50 - 250 m 2 / g.

3. The method according to claim 1, characterized in that in the heteroatom ZSM-5 molecular sieve, the micropore specific surface area accounts for 70% - 100% of the total specific surface area of the molecular sieve.

4. The method according to claim 1, wherein: the weight ratio between the active ingredient in component I and component II is 0.1 - 20.

5. The method according to claim 1, wherein: a dispersant is also added to component I, and the metal oxide is dispersed in the dispersant. The dispersant is one or more of SiO2, ZrO2, TiO2, Ga2O3, activated carbon, graphene, and carbon nanotubes.

6. The method according to claim 5, characterized in that: in component I, the content of the dispersant is 0.05 - 90 wt%.

7. The method according to claim 1, characterized in that: the pressure of the syngas is 0.5 - 10 MPa; the reaction temperature is 300 - 600 °C; the space velocity is 300 - 12000 mL / g / h; the syngas is a H2 / CO mixed gas, and the H2 / CO ratio is 0.2 - 3.5.

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