Catalyst for catalytic synthesis gas direct conversion to produce BTX-rich aromatic hydrocarbons and application thereof

Abstract

The application discloses a kind of catalyst and the method for directly converting synthesis gas to prepare aromatic hydrocarbon rich in benzene (B), toluene (T), dimethyl benzene (X), belongs to synthesis gas directly preparing aromatic hydrocarbon, with synthesis gas as reaction raw material, conversion reaction is carried out on fixed bed, the catalyst is composite catalyst I+II+III, three components are mechanically mixed, and the active component of component I is metal oxide I, component II is molecular sieve, and component III is molecular sieve.Reaction process has very high BTX product yield and selectivity, and aromatic hydrocarbon selectivity can reach 50-80%, and the proportion of benzene, toluene, dimethyl benzene in aromatic hydrocarbon can reach 30-80%, while by-product methane selectivity is less than 10%, with good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of syngas to aromatic hydrocarbon production, specifically relating to a catalyst and a method for the direct conversion of syngas to BTX-rich aromatic hydrocarbons. Background Technology

[0002] Benzene, toluene, and xylene (collectively known as BTX) are important basic chemicals, mainly used in the production of synthetic materials such as polyester and polyurethane. In addition, aromatics are used as gasoline blending components and in the production of pesticides, herbicides, pharmaceuticals, and dyes. Although my country's aromatics production capacity has developed rapidly in recent years, it still cannot meet the demands of national economic development. In 2017, the dependence on imported xylene reached 60%. Currently, large-scale industrial production of BTX mainly relies on petroleum, with over 70% of BTX originating from naphtha reforming. Due to my country's energy structure of being rich in coal but poor in oil, my country heavily relies on imported oil. With the rapid development of my country's economy, the demand for crude oil has increased year by year, and the dependence on imported crude oil exceeds 65%. Therefore, the production of aromatics from non-petroleum resources such as coal, natural gas, and biomass will have significant strategic importance. Aromatics can be produced from non-petroleum resources by first converting these resources into syngas (a mixture of CO and H2), and then using the syngas to produce aromatics. Composite catalysts combining metal oxides and ZSM-5 molecular sieves can achieve direct synthesis of aromatics from syngas, but the BTX selectivity is very low, around 30%. In 2017, Professor Wang Ye's team at Xiamen University coupled Zn-ZrO2 with ZSM-5 molecular sieves, achieving an aromatics selectivity of 80% at a CO conversion rate of 20%, but the BTX selectivity was only 21.9%. Although shielding the BTX selectivity by acidic sites on the outer surface of the ZSM-5 molecular sieve can improve the BTX selectivity, the silicon deposited on the outer surface partially blocks the pores, leading to a decrease in CO conversion, aromatics selectivity, and catalyst efficiency. Therefore, developing catalysts that can directly produce high BTX selectivity and stable efficiency from syngas is of great significance to my country's energy, textile, chemical fiber, and plastics industries. Summary of the Invention

[0003] To address the above problems, this invention provides a method for the direct conversion of catalyst and syngas into BTX-rich aromatics.

[0004] The technical solution of this invention is as follows:

[0005] A catalyst, which is a composite catalyst, comprises component I, component II, and component III; component I includes a metal oxide; component II is one or both of ZSM-5 and ZSM-11 molecular sieves; and component III is one or more of SAPO-34, SAPO-18, or SAPO-17; wherein components I, II, and III are compounded in a powder mixing manner to form I+II+III; and the active component metal oxide I in component I is ZrO2, Cr2O3, or ZnCr x O (1+1.5x) ZnAl x O (1+1.5x) ZnCr x Al y O (1+1.5x+1.5y) ZnZr x O (1+2x) ZnGa x O (1+1.5x) ZnIn x O (2+1.5x) MnCr x O y ZnMn x O y MnGa x O y One or more of the following; the value of x is in the range of 1 to 3.5, and the value of y is in the range of 0.1 to 10.

[0006] Based on the above technical solutions, preferably, in component II, the silica-alumina ratio of the ZSM-5 or ZSM-11 molecular sieve is 20-1000, preferably 50-800, and more preferably 50-600;

[0007] Based on the above technical solution, preferably, component II has the characteristics of a moderately strong acid, and the amount of the moderately strong acid site is 0.05-0.5 mol / kg, preferably 0.05-0.4 mol / kg, and more preferably 0.05-0.3 mol / kg.

[0008] Among them, the temperature range corresponding to the peak apex of the NH3-TPD desorption peak for moderately strong acids is 200-500℃; acetone is used as the probe molecule. 13 The C-NMR chemical shift is in the range of 210-220 ppm.

[0009] Based on the above technical solutions, preferably, the skeletal element composition of component III can be one or more of Si-O, Si-Al-O, Si-BO, Si-Al-Ti-O, Ga-Si-O, Ga-Si-Al-O, Mg-Al-PO, Fe-Si-O, and As-Si-O.

[0010] Based on the above technical solution, preferably, component III has the characteristics of a moderately strong acid, and the amount of the moderately strong acid site is 0.05-2.5 mol / kg, selected as 0.05-2.0 mol / kg. The temperature range corresponding to the peak apex of the NH3-TPD desorption peak for the moderately strong acid is 200-500℃; acetone is used as the probe molecule. 13 The C-NMR chemical shift is in the range of 210-220 ppm.

[0011] The acid strength is defined by the NH3-TPD peak and includes three types of acidity: weak acid, moderately strong acid, and strong acid.

[0012] The NH3-TPD method is based on the desorption peak position of NH3. The position of the desorption peak refers to the position of the desorption peak. Under standard test conditions, with a sample mass w to carrier gas flow rate f ratio (w / f) = 100 g·h / L and a heating rate of 10℃ / min, the TCD records the thermal conductivity signal of desorbed NH3 and plots the desorption curve. Based on the peak position of the curve, the inorganic solid is divided into three acid strengths: weak acid refers to acidic sites with an NH3 desorption temperature below 275℃; moderately strong acid refers to acidic sites with an NH3 desorption temperature between 275-500℃; and strong acid refers to acidic sites with an NH3 desorption temperature above 500℃.

[0013] Based on the above technical solutions, preferably, the weight ratio between the active ingredient in component I and component II is 0.1-20:1, more preferably 0.3-5:1; the weight ratio between the active ingredient in component I and component III is 0.1-20:1, more preferably 0.3-5:1.

[0014] Based on the above technical solution, preferably, component I further includes a dispersant, wherein metal oxide I is dispersed in the dispersant; the active ingredient is metal oxide I; and the dispersant is one or more of Al2O3, SiO2, TiO2, activated carbon, graphene, and carbon nanotubes.

[0015] Based on the above technical solution, preferably, in component I, the content of dispersant is 0.05-90 wt%, and the remainder is metal oxide I.

[0016] Based on the above technical solution, preferably, H may or may not be connected to the O element of the molecular sieve framework of component II and component III; and the H can be wholly or partially replaced by one or more of Na, Mg, Sn, Mn, Ag, Mo, Cr, Fe, Co, V, Pt, Pd, Ti, Zn, Ga, As, and Ge through ion exchange, and the molar ratio of the total metal to the Brønsted acid of the molecular sieve (here, the molecular sieve refers to the total molecular sieve of component II and component III) is 1-30%.

[0017] Another aspect of the present invention provides a method for the direct conversion of syngas into benzene, toluene, and xylene, which uses syngas as a reactant and carries out the conversion reaction in a fixed bed, and the catalyst used is the catalyst described above.

[0018] The pressure of the synthesis gas is 0.5-10 MPa, preferably 1-8 MPa; the reaction temperature is 300-600℃, preferably 350-500℃; and the space velocity is 300-12000 ml / g. cat / h, preferably 300-9000ml / g cat / h, more preferably 300-7000 ml / g cat / h; the synthesis gas is an H2 / CO mixture, with an H2 / CO ratio of 0.2-3.5, preferably 0.3-2.5.

[0019] The composite catalyst is used for one-step direct conversion of syngas into BTX-rich aromatics, wherein the selectivity of aromatics can reach 50-80%, preferably 65-80%, the proportion of BTX in the aromatics is 30-80%, preferably 60-80%, and the selectivity of the by-product methane is less than 10%.

[0020] Beneficial effects

[0021] 1. Unlike traditional Fischer-Tropsch synthesis for producing liquid fuels, this technology achieves a one-step, efficient conversion of syngas into BTX. The proportion of BTX in the aromatic products is high, reaching 30-80%.

[0022] 2. Using components I, II, or III individually, or in combination (I+II, I+III, II+III), as described in this invention, cannot fully achieve the functions of this invention. For example, using component I alone results in very high methane selectivity but very low conversion rate, while using component II, III, or II+III alone cannot activate and convert syngas. Using I+II can achieve direct conversion of syngas to aromatics, but the BTX selectivity is very low. Using I+III cannot achieve syngas to aromatics, and the products are mostly low-carbon olefins. Only the synergistic catalysis of components I, II, and III can achieve direct conversion of syngas to BTX-rich aromatics.

[0023] 3. The composite catalyst in this invention has a simple preparation process and mild conditions; and the reaction process has a high product yield and selectivity, with an aromatic selectivity of 50-80%, of which the BTX ratio can reach 30-80%, while the by-product methane has a low selectivity (less than 10%). Detailed Implementation

[0024] The present invention will be further illustrated below by way of embodiments, but the scope of the claims of the present invention is not limited to these embodiments. Furthermore, the embodiments only provide some conditions for achieving this objective, but do not imply that these conditions must be met to achieve this objective.

[0025] The specific surface area of ​​a sample can be tested by physical adsorption of nitrogen or argon.

[0026] The metal oxide I described in this invention can be obtained by purchasing commercially available metal oxides with high specific surface area, or by the following methods:

[0027] I. Preparation of Catalyst Component I

[0028] (I) Precipitation method for synthesizing ZrO2 materials:

[0029] Weigh 0.5 g of zirconium oxynitrate into a container, then weigh 0.795 g (7.5 mmol) and add it to the same container. Add 30 ml of deionized water to the container, and stir at 70°C for at least 0.5 h to ensure the solution is homogeneous. Allow to cool naturally to room temperature. Centrifuge the reaction mixture, collect the precipitate, and wash twice with deionized water to obtain the ZrO2 metal oxide precursor. Dry the obtained product in air and then calcine it at 500°C for 3 h to obtain the ZrO2 material. This is denoted as Ox⁻¹.

[0030] (II) Precipitation method for the synthesis of ZnCr x O (1+1.5x) ZnAl x O (1+1.5x) ZnCr x Al y O (1+1.5x+1.5y) ZnZr x O (1+2x) ZnGa x O (1+1.5x) ZnIn x O (2+1.5x) MnCr x O y :

[0031] One or more of zinc nitrate, chromium nitrate, manganese nitrate, zirconium nitrate, gallium nitrate, and indium nitrate are used as precursors, along with dispersants such as aluminum nitrate, titanium nitrate, activated carbon, graphene, and carbon nanotubes, as well as dispersant precursors and ammonium carbonate, and mixed in water at room temperature (ammonium carbonate is used as a precipitant, with an excess of ammonium carbonate or preferably a 1:1 ratio of ammonium ions to metal ions). The mixture is aged, then washed, filtered, and dried. The resulting solid is calcined in air to obtain component I. The specific samples and their preparation conditions are shown in Table 1 below.

[0032] Table 1 Preparation of Component I

[0033]

[0034] II. Preparation of Component II

[0035] The moderately strong acids described in this invention can be tested using methods such as solid-state NMR spectroscopy (H-N), NH3-TPD, infrared spectroscopy, and chemical titration. However, the methods for testing acidity are not limited to those described above.

[0036] Component II of this invention can be a commercially available ZSM-5 or ZSM-11 molecular sieve with an acid density that meets the requirements of this invention, or it can be a self-synthesized molecular sieve. Here, ZSM-5 and ZSM-11 molecular sieves prepared by hydrothermal synthesis are taken as examples.

[0037] The specific preparation process is as follows:

[0038] Raw materials were weighed according to the oxide ratio of SiO2:Al2O3:TPAOH:H2O = 1:0.02-0.0017:0.4:45 (molar ratio): silicon source, aluminum source, tetrapropylammonium hydroxide, and deionized water. The mixture was stirred at room temperature for 2 hours, then transferred to a hydrothermal reactor and crystallized at 160-180℃ for 4-7 days. The mixture was then rapidly cooled to room temperature in a water bath and repeatedly centrifuged and washed until the pH of the supernatant was 7 at the end of the washing process. The precipitate was dried at 110℃ for 12 hours and then calcined in air at 600℃ for 3 hours to obtain ZSM-5 molecular sieve.

[0039] Raw materials were weighed according to the oxide ratio of SiO2:Al2O3:TBAOH:H2O = 1:0.02-0.0017:0.4:45 (molar ratio): silicon source, aluminum source, tetrabutylammonium hydroxide, and deionized water. The mixture was stirred at room temperature for 2 hours, then transferred to a hydrothermal reactor and crystallized at 160-180℃ for 1-7 days. The mixture was then rapidly cooled to room temperature in a water bath and repeatedly centrifuged and washed until the pH of the supernatant was 7 at the end of the washing process. The precipitate was dried at 110℃ for 12 hours and then calcined in air at 600℃ for 3 hours to obtain ZSM-11 molecular sieve.

[0040] The silicon source is selected from one or more of TEOS, silica sol, and silica; the aluminum source is selected from one or more of sodium aluminate, Al(OH)3, AlOOH, and aluminum isopropoxide.

[0041] The framework element composition of the ZSM-5 molecular sieve or ZSM-11 molecular sieve may be one or more of the following: Si-O, Si-Al-O, Si-BO, Si-Al-Ti-O, Ga-Si-O, Ga-Si-Al-O, Mg-Al-PO, Fe-Si-O, and As-Si-O.

[0042] H is connected to the O element of some skeletons, and the corresponding products are defined as fraction 2-1, fraction 2-2, fraction 2-3, and fraction 2-4 respectively.

[0043] Table 2. Preparation and performance parameters of ZSM-5 and ZSM-11 molecular sieves

[0044]

[0045]

[0046] Preparation of Comparative Component II (MOR molecular sieve) 2-5: Raw materials were weighed according to the following molar ratio: SiO2:Al2O3:NaOH:H2O = 1:0.05:0.375:32: silicon source, aluminum source, sodium hydroxide, and deionized water. The mixture was stirred at room temperature and then transferred to a reaction vessel for dynamic crystallization at 160℃ for 48 hours. The mixture was then rapidly cooled to room temperature in a water bath and repeatedly centrifuged and washed until the pH of the supernatant was 7. The precipitate was dried at 110℃ for 12 hours and then calcined in air at 600℃ for 3 hours to obtain Na-type MOR molecular sieve. The synthesized Na-type MOR molecular sieve was subjected to ammonium exchange with a 1.0 mol / L ammonium chloride solution at 80℃ to remove Na+. + Exchange for NH4 + (The volume ratio of ammonium chloride solution to molecular sieve mass is 50 ml / g), repeated three times, with each exchange lasting 2 hours. Afterward, the mixture is centrifuged, washed, and dried, then transferred to a muffle furnace and calcined in air at 500°C for 2 hours to obtain H-type MOR molecular sieve.

[0047] III. Preparation of Component III (SAPO-34, SAPO-18, or SAPO-17):

[0048] Component III of this invention can be a commercially available SAPO-34, SAPO-18, or SAPO-17 molecular sieve with an acid density that meets the requirements of this invention, or it can be a self-synthesized molecular sieve. Here, we take a commercially available molecular sieve as an example, as shown in the table below.

[0049] Table 3. Medium-strong acid content of SAPO-34, SAPO-18, or SAPO-17 molecular sieves

[0050] Sample number Molecular sieve moderately strong acid content mol / kg Divided into 3-1 SAPO-34 0.4 Divide into 3-2 SAPO-18 0.3 Divide into 3-3 SAPO-17 0.5

[0051] III. Catalyst Preparation

[0052] Preparation of I+II+III composite catalyst:

[0053] Catalyst I, Catalyst II, and Catalyst III are added to a container in the required proportions. The separation, crushing, and mixing are achieved by utilizing one or more of the following forces generated by the high-speed movement of these materials and / or the container: extrusion force, impact force, shearing force, and friction force. The conversion of mechanical energy, thermal energy, and chemical energy is achieved by adjusting the temperature and carrier gas atmosphere, and the interaction between different components is further regulated.

[0054] Powder mixing can be achieved by one or more of the following methods: mechanical stirring, grinding, and ball milling.

[0055] The weight ratio of component I, component II and component III is 1:0-10:0-10, preferably 1:0.5-5:0.5-5, and more preferably 1:0.5-3:0.5-3.

[0056] The specific catalyst preparation is shown in Table 4.

[0057] The preparation of the comparative catalysts is shown in Table 5.

[0058] Table 4. Preparation and parameter characteristics of I+II+III composite catalysts

[0059] Catalyst number Catalyst component I Catalyst Component II Catalyst component III I:II:III weight ratio Mixing method I+II+Ⅲ-1 0x-1 Divide into 2-1 Divided into 3-1 1：1：2 Grinding I+II+III-2 0x-1 Divide into 2-1 Divided into 3-1 1：3：1.5 Grinding I+II+III-3 0x-2 Divide into 2-2 Divide into 3-2 1：1.5：1.5 ball milling I+II+III-4 0x-2 Divide into 2-2 Divide into 3-2 1：2：1 ball milling I+II+Ⅲ-5 0x-3 Divide into 2-3 Divide into 3-3 1：1.5：1.5 Mechanical mixing I+II+Ⅲ-6 0x-4 Divided into 2-4 Divided into 3-1 1：1.5：1.5 Mechanical mixing I+II+Ⅲ-7 0x-5 Divide into 2-1 Divided into 3-1 1：1.5：1.5 Grinding I+II+III-8 0x-6 Divide into 2-1 Divided into 3-1 1：1.5：1.5 Grinding I+II+Ⅲ-9 Ox-7 Divide into 2-1 Divided into 3-1 1：1.5：1.5 Grinding

[0060] Table 5. Preparation and parameter characteristics of comparative composite catalysts

[0061] Catalyst number Catalyst component I Catalyst Component II Catalyst component III I:II:III weight ratio Mixing method Comparison Catalyst 1 0x-1 - - 1:0:0 - Comparison Catalyst 2 - Divide into 2-1 Divided into 3-1 0:1:1 Grinding Comparison Catalyst 3 0x-2 - Divide into 3-2 1:0:1 Grinding Comparison Catalyst 4 0x-1 Divided into 2-5 - 1:1:0 Grinding Comparison Catalyst 5 0x-3 Divide into 2-3 - 1:1:0 Grinding Comparison Catalyst 6 0x-1 Divide into 2-1 Divided into 3-1 1:2:1 Particle Mixing Comparison Catalyst 7 0x-1 Divided into 2-5 Divided into 3-1 1:1:1 Grinding

[0062] Examples of catalytic reactions

[0063] The fixed-bed reactor is equipped with a gas mass flow meter and an online product analysis chromatograph (the reactor exhaust gas is directly connected to the quantitative valve of the chromatograph for periodic real-time sampling and analysis).

[0064] 2g of the catalyst of the present invention was placed in a fixed-bed reactor. The air in the reactor was replaced with Ar, and then the temperature was raised to 300°C. The synthesis gas was switched (H2 / CO molar ratio = 1) at a pressure of 4MPa. The temperature was raised to the reaction temperature of 430°C, and the space velocity of the reactant gas was adjusted to 2500 ml / g / h. The product was analyzed by online chromatography.

[0065] Table 6 lists the specific applications of the catalysts and their effect data.

[0066] Table 6. Specific applications and effect data of catalysts.

[0067]

[0068] The catalyst used in Comparative Example 1 contained only component I and did not include components II and III, resulting in extremely low conversion and no aromatics in the product.

[0069] Comparative Example 2 used a catalyst that did not contain component I but contained components II and III, and the CO conversion rate was 0.

[0070] The catalyst used in Comparative Example 3 did not contain component II, but contained components I and III, and the product contained no aromatics.

[0071] The catalyst used in Comparative Example 4 did not contain component III, but contained components I and II, and component II was replaced by MOR molecular sieve instead of ZSM-5 or ZSM-11. The aromatic selectivity in the product was only 2%.

[0072] The catalyst used in Comparative Example 5 did not contain component III, but contained components I and II, and the BTX selectivity in aromatics was only 25%.

[0073] In Comparative Example 6, the mixing method of components I+II+III was changed from powder mixing to particle mixing in the catalyst, and the selectivity of aromatics was only 32%, while the selectivity of BTX was only 35%.

[0074] In Comparative Example 7, component II was replaced with component 2-5 in the catalyst, and then component I + II + III powders were mixed. The aromatic selectivity in the product was only 2%.

[0075] As can be seen from the table above, the topological structure of the molecular sieve, the matching between catalyst components I, II and III, and the mixing method of the three components are crucial, directly affecting the conversion rate of carbon monoxide, the selectivity of aromatics, and the proportion of BTX.

[0076] The composite catalyst in this invention is simple to prepare under mild conditions; and the reaction process has high product yield and selectivity. The method of this invention can achieve an aromatic selectivity of 50-80%, of which the BTX ratio can reach 30-80%, while the byproduct methane has low selectivity (less than 10%).

Claims

1. A catalyst characterized by: The catalyst is a composite catalyst, comprising component I, component II, and component III; component I includes metal oxide I; component II is one or both of ZSM-5 and ZSM-11 molecular sieves; and component III is one or more of SAPO-34, SAPO-18, or SAPO-17; in the catalyst, components I, II, and III are compounded in a powder mixing manner to form I+II+III; the active component metal oxide I in component I is ZrO2, Cr2O3, or ZnCr. x O （1+1.5x） ZnAl x O （1+1.5x） ZnCr x Al y O （1+1.5x+1.5y） ZnZr x O （1+2x） ZnGa x O （1+1.5x） ZnIn x O （2+1.5x） MnCr x O y ZnMn x O y MnGa x O y One or more of the following; the value of x is in the range of 1 to 3.5, and the value of y is in the range of 0.1 to 10.

2. Catalyst according to claim 1, characterized in that: In component II, the silica-alumina ratio of ZSM-5 molecular sieve or ZSM-11 molecular sieve is 20-1000; the ZSM-5 molecular sieve or ZSM-11 molecular sieve has the characteristics of medium-strong acid, and the amount of medium-strong acid sites is 0.05-0.5 mol / kg.

3. The catalyst according to claim 1, characterized in that: In component II, the silica-alumina ratio of ZSM-5 molecular sieve or ZSM-11 molecular sieve is 50-800.

4. The catalyst according to claim 1, characterized in that: In component II, the silica-alumina ratio of ZSM-5 molecular sieve or ZSM-11 molecular sieve is 50-600.

5. The catalyst according to claim 1, characterized in that: In component III, the molecular sieve framework elements of SAPO-34, SAPO-18, or SAPO-17 are one or more of Si-O, Si-Al-O, Si-BO, Si-Al-Ti-O, Ga-Si-O, Ga-Si-Al-O, Mg-Al-PO, Fe-Si-O, and As-Si-O; component III has the characteristics of a moderately strong acid, and the amount of moderately strong acid sites is 0.05-2.5 mol / kg.

6. The catalyst according to claim 1, characterized in that: The powder mixing method for components I, II and III is to uniformly mix components I, II and III by grinding.

7. The catalyst according to claim 1, characterized in that: The weight ratio of the active ingredient in component I to component II is 0.1-20:1; the weight ratio of the active ingredient in component I to component III is 0.1-20:

1.

8. The catalyst according to claim 1, characterized in that: The weight ratio of the active ingredient in component I to component II is 0.3-5:1; the weight ratio of the active ingredient in component I to component III is 0.3-5:

1.

9. The catalyst according to claim 1, characterized in that: Component I further includes a dispersant, in which metal oxide I is dispersed. The dispersant is one or more of Al2O3, SiO2, TiO2, activated carbon, graphene, and carbon nanotubes. The content of the dispersant in component I is 0.05-90 wt%, and the remainder is metal oxide I.

10. A process for the direct conversion of synthesis gas to aromatics rich in BTX, characterized in that: Syngas is used as the reaction feedstock, and the conversion reaction is carried out in a fixed bed. The catalyst used is any one of the catalysts described in claims 1-9. The pressure of the synthesis gas is 0.5-10 MPa; the reaction temperature is 300-600℃; and the space velocity is 300-12000 ml / g. cat / h; the synthesis gas is an H2 / CO mixture with an H2 / CO molar ratio of 0.2-3.5; the method achieves an aromatic selectivity of 50-80% and a methane selectivity of less than 10%; benzene, toluene, and xylene account for 30-80% of the aromatics.

11. The process for the direct conversion of synthesis gas to aromatics rich in BTX according to claim 10, characterized in that: The pressure of the synthesis gas is 1-8 MPa; the reaction temperature is 350-500℃; and the space velocity is 300-9000 ml / g. cat / h; the synthesis gas is an H2 / CO mixture with an H2 / CO molar ratio of 0.3-2.5.

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