A process for the production of mixed isomeric alkanes from synthesis gas and a catalyst therefor

Abstract

The present invention provides a method for converting synthesis gas to mixed isomeric alkanes and a catalyst therefor, characterized in that a feedstock comprising isomeric alkenes, synthesis gas and a catalyst are contacted under synthesis gas conversion conditions, wherein the catalyst comprises a support, a synthesis gas conversion active component selected from at least one first metal component of Group VIII and at least one second metal component selected from Group VIB and / or VIIB. Compared with the prior art method for producing isomeric alkanes, the method of the present invention is simpler and has higher selectivity for isomeric alkanes.

Description

Technical Field

[0001] This invention relates to a method for directly producing mixed isoalkanes from syngas and a dedicated catalyst thereof. Background Technology

[0002] Fischer-Tropsch synthesis is a core process in the energy and chemical industry for the optimized utilization of non-petroleum carbon resources such as coal, biomass, and shale gas through syngas conversion. Hydrocarbons produced using Fischer-Tropsch synthesis and other technologies exhibit excellent performance and can be used directly or blended with fuels produced from low-quality crude oil to meet increasingly stringent environmental and fuel performance requirements. However, current low oil prices, with no immediate prospect of recovery, coupled with rising coal prices due to coal rationing policies, limit the profitability of indirect coal liquefaction using Fischer-Tropsch synthesis technology, and also suffer from severe technological homogenization. How to transform these challenges into opportunities in syngas chemistry and achieve differentiation, high-end development, and high added value in syngas conversion products is a question currently being considered by both academia and industry.

[0003] Fischer-Tropsch synthesis products can be hydroisomerized to obtain high-grade lubricating oil base oils or isoparaffin solvent oils, thus realizing the high-value utilization of Fischer-Tropsch products. CN105521818A discloses a hydroisomerization catalyst, its preparation method, and its application. When used as a catalyst for the hydroisomerization reaction of Fischer-Tropsch synthesis waxes, the hydroisomerization catalyst can effectively convert long-chain alkanes in Fischer-Tropsch synthesis waxes into multi-branched isoparaffins, obtaining a high yield of isomerization products. Simultaneously, the obtained isomerization products have low pour points and high viscosity indexes, making them suitable as lubricating oil base oils. CN101921621A discloses a method for producing isoparaffin solvent oils. This method uses distillate oils or light de-oiling as raw materials and employs a combined process of hydrotreatment-hydroisomerization-hydrorefining to produce isoparaffin solvent oils.

[0004] In summary, mixed isoalkanes are important raw materials for lubricating oil base oils and isoalkane solvent oils, and there is still a need to develop methods for producing mixed isoalkanes with simpler processes. Summary of the Invention

[0005] The purpose of this invention is to provide a method for producing mixed isoalkanes from syngas.

[0006] The present invention also provides a dedicated catalyst for implementing the above method and a method for preparing the same.

[0007] The first aspect of the present invention provides a method for producing mixed isoalkanes from syngas, characterized in that, under syngas conversion reaction conditions, a feedstock containing isoalkenes, syngas, and a special catalyst are contacted.

[0008] The isoolefin is selected from one or more of C4 to C10 isoolefins.

[0009] The syngas conversion reaction conditions include a temperature of 50-350℃, a pressure of 0.1-15MPa, and a molar ratio of H2 to CO in the syngas of 0.4-3.

[0010] A second aspect of the present invention provides a dedicated catalyst for the conversion of syngas into mixed isoalkanes, the catalyst comprising a support and an active metal component supported on the support, characterized in that the active metal component comprises at least one first metal component M1 selected from Group VIII non-noble metals and at least one second metal component M2 selected from Group VIB and / or VIIB metals.

[0011] Compared with existing methods for producing isoalkanes, the method of directly producing mixed isoalkanes from syngas conversion of the present invention is simpler and has higher isoalkanes selectivity. The resulting liquid products, due to their high isoalkanes content, become various high-quality oil products. For example, the product components with a distillation range <150°C are high-quality naphtha or high-quality solvent oils; the product components with a distillation range of 200-320°C are high-quality diesel oils; and the product components with a distillation range >320°C are high-quality lubricating oil base stock. It is particularly noteworthy that the product components with a distillation range >320°C contain a high content of isoalkanes, which significantly reduces the severity of subsequent isoalkanes dewaxing and processing into lubricating oil base stock, thus making them a high-quality lubricating oil base stock. Compared with existing technologies, this method is simpler and has higher isoalkanes selectivity. Specifically, using the method of the present invention and a dedicated catalyst, while maintaining similar conversion rates and methane selectivity to conventional Fischer-Tropsch synthesis, the isoalkanes selectivity is significantly increased from 40.7% (excluding the second metal component) to 65.4%.

[0012] These examples demonstrate that the method and dedicated catalyst provided by this invention can conveniently convert syngas directly into mixed isoalkanes with high selectivity for isoalkanes.

[0013] Other features and advantages of the present invention will be described in detail in the following detailed description section. Detailed Implementation

[0014] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0015] This invention provides a method for producing mixed isoalkanes from syngas, characterized in that, under syngas conversion reaction conditions, the feedstock containing isoalkenes, syngas, and a special catalyst are contacted.

[0016] The isoolefin is selected from C4 to C5. 10 One or more of the isomeric olefins, preferably at least one of isobutene, isopentenene, isohexene, isoheptene, isooctene, isononene, and isodecanene, more preferably at least one of isobutene, 2-methyl-1-butene, 2-methyl-2-butene, 3-methyl-1-butene, 2-methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 2-methyl-2-pentene, 3-methyl-2-pentene, and 4-methyl-2-pentene.

[0017] The syngas conversion reaction conditions include a temperature of 50-350℃, preferably 100-280℃, more preferably 180-250℃, a pressure of 0.1-15MPa, preferably 1-5MPa, and a syngas H2 to CO molar ratio of 0.4-3, preferably 1-2.5.

[0018] The contact reaction apparatus is either a batch reactor or a continuous reactor. The batch reactor includes a batch autoclave reactor. The continuous reactor includes a fixed-bed reactor, a slurry-bed reactor, a moving-bed reactor, or a fluidized-bed reactor. A continuous reactor is preferred.

[0019] The space-time velocity of the syngas used in the continuous reactor is 200-20000 h⁻¹. -1 Preferably 500-12000 hours -1 The reaction time of the batch reactor is 1-200 hours, preferably 2-50 hours.

[0020] The space-time velocity of the isoolefin satisfies a CO to isoolefin molar ratio of 1-2000, preferably 2-1000, more preferably 3-300, and particularly preferably 5-100.

[0021] A dedicated catalyst for the conversion of syngas into mixed isoalkanes, the catalyst comprising a support and an active metal component supported on the support, characterized in that the active metal component comprises at least one first metal component M1 selected from Group VIII non-noble metals and at least one second metal component M2 selected from Group VIB and / or VIIB metals.

[0022] The catalyst satisfies (M2 / M1) XPS / (M2 / M1) XRF = 1.5-20.0, preferably 2.5-10, more preferably 3-5. Wherein, (M2 / M1) XPS The ratio of the second metal component to the first metal component of the catalyst, expressed as an element, is defined by X-ray photoelectron spectroscopy (M2 / M1). XRFIt is the weight ratio of the second metal component to the first metal component in the catalyst, characterized by X-ray fluorescence spectroscopy, based on elemental composition.

[0023] The first metal component M1 of the catalyst is selected from at least one element of Group VIII, preferably at least one of cobalt, iron, and ruthenium. The second metal component M2 of the catalyst is selected from at least one element of Group VIB or Group VIIB, preferably at least one of Mo, W, Re, and Mn.

[0024] The loading of the first metal component M1 is 5-70% by weight, preferably 8-50% by weight, and more preferably 10-30% by weight; the content of the second metal component M2 is 0.01-10% by weight, preferably 0.02-8% by weight, and more preferably 0.05-5% by weight.

[0025] The catalyst further comprises a metal promoter selected from at least one of Pt, Pd, Ru, Rh, Ir, La, Zr, Ce, Y, and Cu. Based on the total weight of the catalyst, the metal promoter comprises 0-10% by weight, preferably 0.5-6% by weight, calculated as a metal element.

[0026] The catalyst support can be any support suitable for Fischer-Tropsch synthesis, such as one or more of alumina, silica, titanium dioxide, magnesium oxide, zirconium oxide, thorium oxide, beryllium oxide, clay, molecular sieves, and activated carbon, preferably one or more of alumina, silica, titanium dioxide, and activated carbon. The support can also be one or more of the above-mentioned supports modified with one or more of phosphorus, silicon, fluorine, boron, and carbon. These modified supports are commercially available or can be obtained by existing modification methods.

[0027] The preparation method of the special catalyst includes the following steps:

[0028] The supported catalyst is obtained by impregnating a support with a solution containing at least one compound selected from Group VIII non-noble metals, a first metal component M1, and a compound selected from Group VIB and / or VIIB, and then drying, calcining, or not calcining the impregnated support in sequence.

[0029] The preparation method of the special catalyst preferably includes the following steps:

[0030] (1) Impregnate the carrier with a solution containing at least one compound selected from the first metal component M1 of a non-noble metal of Group VIII, and then subject the impregnated carrier to drying, calcining or no calcining, and reduction activation in sequence.

[0031] (2) The product obtained in step (1) is impregnated with a solution of a compound containing a second metal component selected from Group VIB and / or VIIB under a reducing or inert atmosphere, and then dried and optionally calcined to obtain the supported catalyst.

[0032] The impregnation conditions include a temperature of 10-90℃, preferably 15-40℃, and a time of 1-24 hours, preferably 2-6 hours. The drying conditions include a temperature of 60-350℃, preferably 100-200℃, and a time of 1-24 hours, preferably 2-6 hours. When the catalyst needs to be calcined, the calcination temperature is aimed at converting the compound containing the active metal component into its oxide. The preferred calcination temperature is 200-700℃, and the calcination time is 1-12 hours. More preferably, the temperature is 250-500℃, and the calcination time is 2-6 hours.

[0033] The method for introducing the catalyst metal promoter can be implemented in one or more of the following ways:

[0034] 1) First, impregnate the carrier with a solution of a compound containing the metal auxiliary agent, and then impregnate the carrier with a solution of a compound containing an active metal component.

[0035] 2) First, impregnate the carrier with a solution of a compound containing an active metal component, and then impregnate the carrier with a solution of a compound containing the metal auxiliary agent.

[0036] 3) Simultaneously impregnate the carrier with a solution of a compound containing an active metal component and a solution of a compound containing the metal auxiliary agent;

[0037] 4) Prepare an impregnation solution by combining a compound containing an active metal component and a compound containing the metal auxiliaries, and then impregnate the carrier with the impregnation solution.

[0038] The catalyst needs to be reduced with a reducing gas such as hydrogen before use.

[0039] The following embodiments are provided to better understand the present invention, but are not intended to limit the invention. In the following embodiments, unless otherwise specified, all percentage contents refer to mass percentages. The proportion of converted CO to intake CO is defined as CO conversion rate X. CO The molar percentage of CO converted into methane out of the total converted CO is the methane selectivity (S). CH4 The molar percentage of CO produced to produce isoalkanes relative to the total converted CO is the isoalkanes selectivity S. iso .

[0040] To visually compare the different fraction contents and characteristics of the products, the boiling range distribution method for petroleum fractions (ASTM D6352-12) and GC / MS structural analysis were used to determine the fraction weight content and isoalkane selectivity of high-quality diesel oil (200-320℃) and high-quality lubricating oil base oil (>320℃). iso S here iso Defined as the percentage of isoalkanes in the fraction relative to the total weight of the fraction.

[0041] Example 1

[0042] This embodiment is used to illustrate the method and its dedicated catalyst provided by the present invention.

[0043] (1) Catalyst preparation and characterization

[0044] According to the metal salt content required for the equal-volume impregnation method, a 36.1 mL impregnation solution containing cobalt nitrate (208 g / L), platinum (1.38 g / L), and dichlorotetraammineplatinum was prepared. The impregnation solution was decanted onto a 42.5 g SiO2 support (Fuji Silicon Co., Ltd., Japan, average particle size 40-80 μm, the same applies below), stirred at 20°C, allowed to stand for 4 hours, dried at 120°C, calcined at 400°C for 4 hours, and reduced with hydrogen at 400°C for 4 hours at a hydrogen pressure of 0.1 MPa. After reduction, the solution was cooled to room temperature, and 55.1 mL of ammonium metatungstate aqueous solution containing 9.07 g / L tungsten was added under a hydrogen atmosphere. The solution was allowed to stand for 2 hours and then dried with hydrogen. It was then passivated for 0.5 hours with a mixture of O2 / N2 (0.5% volume ratio) and stored in a desiccator for later use. The obtained catalyst was designated R-CoW-1, and its composition, XPS, and XRF characterization results are shown in Table 1. The surface atom ratio (M2 / M1) is obtained by converting the peak areas corresponding to the electron binding energies of W 4f and Co 2p. XPs .

[0045] (2) Method for catalytic conversion of syngas to directly produce mixed isoalkanes

[0046] The R-CoW-1 catalyst was diluted with quartz sand of the same particle size and then loaded into a fixed-bed reactor. It was first reduced with hydrogen at 160 mL / min at 400 °C for 4 hours. After reduction, a feed gas with a composition of H2 / CO / N2 = 56% / 28% / 16% (volume percentage) was introduced into the reactor at 210 °C at 80 mL / min (syngas space-time velocity of 10,000 h⁻¹). -1 Simultaneously, 4-methyl-1-pentene liquid was mixed with the gas at a liquid feed rate of 0.2 mL / h and then introduced into the reactor. The pressure was controlled at 2.5 MPa to start the reaction. After 48 hours of reaction, the gas and liquid samples were analyzed. The reaction results are listed in Table 1.

[0047] Comparative Example 1

[0048] This comparative example is used to illustrate the comparison method.

[0049] (1) Catalyst preparation and characterization

[0050] Same as Example 1.

[0051] (2) Method for catalytic conversion of syngas to directly produce mixed isoalkanes

[0052] The method was followed as in Example 1, except that no liquid was introduced. That is, after reduction, the feed gas was introduced into the reactor at 210°C to start the reaction, but no 4-methyl-1-pentene liquid was introduced. The reaction results are listed in Table 1.

[0053] Comparative Example 2

[0054] This comparative example is used to illustrate the comparison method.

[0055] (1) Catalyst preparation and characterization

[0056] Same as Example 1.

[0057] (2) Method for catalytic conversion of syngas to directly produce mixed isoalkanes

[0058] The method was followed as in Example 1, except that 1-hexene liquid was introduced. Specifically, after reduction, the feed gas was introduced into the reactor at 210°C to begin the reaction, while simultaneously, 1-hexene liquid was mixed with the gas at a liquid feed rate of 0.2 mL / h and then introduced into the reactor to begin the reaction. The gas and liquid samples were analyzed after 48 hours of reaction. The reaction results are listed in Table 1.

[0059] Comparative Example 3

[0060] This comparative example is used to illustrate the effect of the comparative catalyst.

[0061] (1) Catalyst preparation and characterization

[0062] The method is the same as in Example 1, except that no tungsten species are introduced into the catalyst.

[0063] According to the metal salt content required for the equal-volume impregnation method, a 36.1 mL impregnation solution containing cobalt nitrate (208 g / L), platinum (1.38 g / L), and dichlorotetraammineplatinum was prepared. The impregnation solution was decanted onto a 42.5 g SiO2 support, stirred at 20 °C, allowed to stand for 4 hours, dried at 120 °C, calcined at 400 °C for 4 hours, and then reduced with hydrogen at 400 °C for 4 hours at a hydrogen pressure of 0.1 MPa. After reduction, the solution was cooled to room temperature and then passivated for 0.5 hours with a mixed gas of O2 / N2 (0.5% volume ratio) and stored in a desiccator for later use. The obtained catalyst was designated R-Co, and its composition, XPS, and XRF characterization results are shown in Table 1.

[0064] (2) Method for catalytic conversion of syngas to directly produce mixed isoalkanes

[0065] Same as Example 1.

[0066] Example 2

[0067] This embodiment is used to illustrate the method and its dedicated catalyst provided by the present invention.

[0068] (1) Catalyst preparation and characterization

[0069] Catalyst R-CoW-2, which has the same composition as catalyst R-CoW-1 in Example 1, was prepared by co-impregnation method.

[0070] According to the metal salt content required for the equal-volume impregnation method, a 36.1 mL impregnation solution containing cobalt nitrate (208 g / L), platinum (1.38 g / L), tungsten (13.9 g / L), cobalt dichlorotetramineplatinum, and ammonium metatungstate was prepared. The impregnation solution was decanted onto a 42.5 g SiO2 support, stirred at 20°C, allowed to stand for 4 hours, dried at 120°C, calcined at 400°C for 4 hours, and then reduced with hydrogen at 400°C for 4 hours at a hydrogen pressure of 0.1 MPa. After reduction, the solution was cooled to room temperature and then passivated for 0.5 hours with a mixed gas of O2 / N2 volume ratio of 0.5%, and stored in a desiccator for later use. The obtained catalyst was designated R-CoW-2, and the characterization results are shown in Table 1.

[0071] (2) Method for catalytic conversion of syngas to directly produce mixed isoalkanes

[0072] Same as Example 1.

[0073] Example 3

[0074] This embodiment is used to illustrate the method and its dedicated catalyst provided by the present invention.

[0075] (1) Catalyst preparation and characterization

[0076] According to the metal salt content required for the equal-volume impregnation method, a 36.1 mL impregnation solution containing cobalt nitrate (208 g / L), platinum (1.38 g / L), and dichlorotetraammineplatinum was prepared. The impregnation solution was decanted onto 42.5 g of γ-Al₂O₃ support (Sasol alumina, average particle size 40-80 μm, the same applies below), stirred at 20 °C, allowed to stand for 4 hours, dried at 120 °C, calcined at 400 °C for 4 hours, and reduced with hydrogen at 400 °C for 4 hours at a hydrogen pressure of 0.1 MPa. After reduction, the solution was cooled to room temperature, and 55.1 mL of ammonium molybdate aqueous solution containing 4.54 g / L molybdate was added under a hydrogen atmosphere. The solution was allowed to stand for 2 hours and then dried with hydrogen. It was then passivated with a 0.5% O₂ / N₂ mixture for 0.5 hours and stored in a desiccator for later use. The obtained catalyst was designated R-CoMo-1, and the characterization results are shown in Table 1.

[0077] (2) Method for catalytic conversion of syngas to directly produce mixed isoalkanes

[0078] The R-CoMo-1 catalyst was loaded into a fixed-bed reactor and reduced with hydrogen at 160 mL / min at 400 °C for 4 hours. After reduction, a feed gas with a composition of H2 / CO / N2 / isobutylene = 55% / 27.5% / 15.7% / 1.8% (volume percentage) was introduced into the reactor at 210 °C at 90 mL / min (syngas space velocity was 10,000 h⁻¹). -1 The reaction was initiated at a controlled pressure of 2.5 MPa, and the gas and liquid samples were analyzed after 48 hours of reaction. The reaction results are listed in Table 1.

[0079] Example 4

[0080] This embodiment is used to illustrate the method and its dedicated catalyst provided by the present invention.

[0081] (1) Catalyst preparation and characterization

[0082] According to the metal salt content required for the equal-volume impregnation method, a 36.1 mL impregnation solution containing cobalt nitrate (104 g / L), platinum (1.38 g / L), and dichlorotetraammineplatinum was prepared. The impregnation solution was decanted onto a 42.5 g SiO2 support, stirred at 20°C, and allowed to stand for 4 hours. After drying at 120°C, it was calcined at 400°C for 4 hours, and then reduced with hydrogen at 400°C for 4 hours at a hydrogen pressure of 0.1 MPa. After reduction, it was cooled to room temperature, and 55.1 mL of ammonium metatungstate aqueous solution containing 9.07 g / L tungsten was added under a hydrogen atmosphere. The solution was allowed to stand for 2 hours and then dried with hydrogen. It was then passivated for 0.5 hours with a mixture of O2 / N2 (0.5% volume ratio) and stored in a desiccator for later use. The obtained catalyst was designated R-CoW-3, and its composition and characterization results are shown in Table 1.

[0083] (2) Method for catalytic conversion of syngas to directly produce mixed isoalkanes

[0084] The R-CoW-3 catalyst was loaded into a fixed-bed reactor and reduced with hydrogen at 160 mL / min at 400 °C for 4 hours. After reduction, a feed gas with a composition of H2 / CO / N2 = 56% / 28% / 16% (volume percentage) was introduced into the reactor at 220 °C at 80 mL / min (syngas space-time velocity of 10,000 h⁻¹). -1 Simultaneously, 2-methyl-1-pentene liquid was mixed with the gas at a liquid feed rate of 0.2 mL / h and then introduced into the reactor. The pressure was controlled at 2.5 MPa to start the reaction. After 48 hours of reaction, the gas and liquid samples were analyzed. The reaction results are listed in Table 1.

[0085] Example 5

[0086] This embodiment is used to illustrate the method and its dedicated catalyst provided by the present invention.

[0087] (1) Catalyst preparation and characterization

[0088] Same as Example 3.

[0089] (2) Method for catalytic conversion of syngas to directly produce mixed isoalkanes

[0090] The R-CoMo catalyst was reduced with hydrogen at 320 mL / min at 400 °C for 4 hours. After reduction, the catalyst was transferred through a glove box to an autoclave containing 40 g of mediating wax and 10 g of 4-methylpentene. After checking the airtightness, the temperature was raised to 210 °C, and a feed gas with a composition of H2 / CO / N2 = 56% / 28% / 16% (volume percentage) was introduced into the reactor at 160 mL / min (syngas space-time velocity was 10,000 h⁻¹). -1 The pressure was controlled at 2.5 MPa, and 4-methyl-1-pentene liquid was simultaneously mixed with the gas at a liquid feed rate of 0.4 mL / h and then introduced into the reactor to start the reaction. After 120 hours of reaction, the gas and liquid samples were analyzed. The reaction results are listed in Table 1.

[0091] Example 6

[0092] This embodiment is used to illustrate the method and its dedicated catalyst provided by the present invention.

[0093] (1) Catalyst preparation and characterization

[0094] According to the metal salt content required for the equal-volume impregnation method, an impregnation solution containing 54 g / L ruthenium, 5.22 g / L zirconium, ruthenium nitrite dihydrate, and zirconium oxynitrate was prepared in 34.2 mL. The impregnation solution was decanted onto 40 g of γ-Al₂O₃ support, stirred at 25 °C, and allowed to stand for 4 hours. After drying at 120 °C, it was calcined at 350 °C for 4 hours and reduced with hydrogen at 350 °C for 4 hours at a hydrogen pressure of 0.1 MPa. After reduction, it was cooled to room temperature, and 55.1 mL of ammonium metatungstate aqueous solution containing 1.59 g / L tungsten was added under a hydrogen atmosphere. After standing for 2 hours, it was dried with hydrogen. Then, it was passivated with a mixed gas of O₂ / N₂ volume ratio of 0.5% for 0.5 hours and stored in a desiccator for later use. The obtained catalyst is designated R-RuW, and its composition and characterization results are shown in Table 1.

[0095] (2) Method for catalytic conversion of syngas to directly produce mixed isoalkanes

[0096] The R-RuW catalyst was diluted with quartz sand of the same particle size and then loaded into a fixed-bed reactor. It was first reduced with hydrogen at 160 mL / min at 400 °C for 4 hours. After reduction, a feed gas with a composition of H2 / CO / N2 = 56% / 28% / 16% (volume percentage) was introduced into the reactor at 210 °C at 80 mL / min (syngas space-time velocity of 10,000 h⁻¹). -1 Simultaneously, 4-methyl-1-pentene liquid was mixed with the gas at a liquid feed rate of 2 mL / h and then introduced into the reactor. The pressure was controlled at 2.5 MPa to start the reaction. After 48 hours of reaction, the gas and liquid samples were analyzed. The reaction results are listed in Table 1.

[0097] Example 7

[0098] This embodiment is used to illustrate the method and its dedicated catalyst provided by the present invention.

[0099] (1) Catalyst preparation and characterization

[0100] According to the metal salt content required for the equal-volume impregnation method, a 36.1 mL impregnation solution containing cobalt nitrate (104 g / L), platinum (1.38 g / L), and dichlorotetraammineplatinum was prepared. The impregnation solution was decanted onto a 42.5 g γ-Al₂O₃ support, stirred at 20 °C, and allowed to stand for 4 hours. After drying at 120 °C, it was calcined at 400 °C for 4 hours, and then reduced with hydrogen at 400 °C for 4 hours at a hydrogen pressure of 0.1 MPa. After reduction, it was cooled to room temperature, and 55.1 mL of ammonium molybdate aqueous solution containing 4.54 g / L molybdate was added under a hydrogen atmosphere. The solution was allowed to stand for 2 hours and then dried with hydrogen. It was then passivated for 0.5 hours with a 0.5% O₂ / N₂ mixture and stored in a desiccator for later use. The obtained catalyst was designated R-CoMo₂, and the characterization results are shown in Table 1.

[0101] (2) Method for catalytic conversion of syngas to directly produce mixed isoalkanes

[0102] The R-CoMo-2 catalyst was loaded into a fixed-bed reactor and reduced with hydrogen at 160 mL / min at 400 °C for 4 hours. After reduction, a feed gas with a composition of H2 / CO / N2 / isobutylene = 55% / 27.5% / 15.7% / 1.8% (volume percentage) was introduced into the reactor at 220 °C at 90 mL / min (syngas space-time velocity was 10,000 h⁻¹). -1 The reaction was initiated at a controlled pressure of 2.5 MPa, and the gas and liquid samples were analyzed after 48 hours of reaction. The reaction results are listed in Table 1.

[0103] The results of Example 1 and Comparative Example 1 show that, using the method of the present invention, while maintaining similar conversion and methane selectivity to conventional Fischer-Tropsch synthesis, the selectivity for isoalkanes is significantly increased from 5.2% to 65.4%. The results of Example 1 and Comparative Example 2 show that using n-olefins such as 1-hexene yields very few isoalkanes. The results of Example 1 and Comparative Example 3 show that, using the dedicated catalyst of the present invention, while maintaining similar conversion and methane selectivity to conventional Fischer-Tropsch synthesis, the selectivity for isoalkanes is significantly increased from 40.7% (excluding the second metal component) to 65.4%. The results of Examples 1 and 2 show that (M2 / M1) xPS / (M2 / M1) XRF Under preferred conditions, the selectivity for isoalkanes is higher. The results from Examples 1 and 6 show that when the CO / isoalkene molar ratio is within the preferred range, the selectivity for isoalkanes is higher.

[0104] These examples demonstrate that the method and dedicated catalyst provided by this invention can conveniently convert syngas directly into mixed isoalkanes with high selectivity for isoalkanes.

[0105] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0106] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0107]

Claims

1. A method for producing mixed isoalkanes from syngas, characterized in that, Under syngas reforming conditions, C4-C6 compounds will be produced. 10 The feedstock for isomeric olefins, syngas, and catalyst are in contact, wherein the space-time velocity of the isomeric olefins satisfies a CO to isomeric olefin molar ratio of 5-100. The syngas conversion reaction conditions include a temperature of 100-280℃, a pressure of 1-5 MPa, and a H2 to CO molar ratio of 1-2.

5. The catalyst comprises a support and an active component, wherein the active component comprises at least one first metal component M1 selected from cobalt, iron, and ruthenium, and at least one second metal component M2 selected from Mo, W, Re, and Mn, wherein the active component satisfies (M2 / M1). XPS / (M2 / M1) XRF =1.5-20.0, wherein the catalyst support is selected from one or more of alumina, silicon dioxide, titanium dioxide, magnesium oxide, zirconium oxide, thorium oxide, beryllium oxide, clay, and activated carbon.

2. The method according to claim 1, wherein, The isomeric olefin is selected from at least one of 2-methyl-1-butene, 2-methyl-2-butene, 3-methyl-1-butene, 2-methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 2-methyl-2-pentene, 3-methyl-2-pentene, and 4-methyl-2-pentene.

3. The method according to claim 1, wherein, The contact reaction apparatus is either a batch reactor or a continuous reactor, wherein the continuous reactor uses a synthesis gas space-time velocity of 200-20000 hours. -1 And / or the reaction time of the batch reactor is 1-200 hours.

4. The method according to claim 3, wherein, The space-time velocity of the syngas used in the continuous reactor is 500-12000 h⁻¹. -1 And / or the reaction time of the batch reactor is 2-50 hours.

5. The method according to claim 1, wherein, The space-time velocity of the isoolefin satisfies a molar ratio of CO to isoolefin of 15-38.

6. The method according to claim 1, wherein, The active components of the catalyst satisfy (M2 / M1). XPS / (M2 / M1) XRF =1.5-10.

0.

7. The method according to claim 1, wherein, The active components of the catalyst satisfy (M2 / M1). XPS / (M2 / M1) XRF =2.5-5.

8. The method according to claim 1, 6 or 7, wherein, The loading of the first metal component M1 is 5-70% by weight, and the content of the second metal component M2 is 0.01-10% by weight.

9. The method according to claim 1, 6 or 7, wherein, The loading of the first metal component M1 is 8-50% by weight, and the content of the second metal component M2 is 0.02-8% by weight.

10. The method according to claim 1, 6, or 7, wherein, The loading of the first metal component M1 is 10-30% by weight; the content of the second metal component M2 is 0.05-5% by weight.

11. The method according to claim 1, wherein, The catalyst support is selected from one or more of the supports modified with one or more of phosphorus, silicon, fluorine, boron, and carbon.

12. The method according to claim 1, wherein, The catalyst further comprises a metal promoter selected from at least one of Pt, Pd, Ru, Rh, Ir, La, Zr, Ce, Y, and Cu.

13. The method according to claim 12, wherein, Based on the total weight of the catalyst, the content of the metal additive, calculated as metal element, is 0.05-6% by weight.

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