Catalyst for directly preparing olefin from synthesis gas as well as preparation method and application of catalyst

Abstract

The invention discloses a catalyst for direct preparation of olefin from synthesis gas and a preparation method and application thereof, the catalyst comprises a carrier and active components loaded on the carrier, the active components comprise an iron element, a copper element and a B element, and the B element is selected from an Eu element and / or a Gd element. The pore diameter of the catalyst is 2-100 nm, and preferably, the pore diameter of the catalyst is in multi-stage distribution. The catalyst has the advantages of high CO conversion rate and high C4 < + > alpha-olefin selectivity when being applied to direct preparation of olefin from synthesis gas.

Description

Technical Field

[0001] The present invention belongs to the field of catalysts, and particularly relates to a catalyst for directly synthesizing olefins from syngas, a preparation method thereof, and an application thereof. Background Art

[0002] Efficient conversion of syngas (mainly composed of CO and H2) into olefins is a main route in modern coal chemical industry. The routes for preparing olefins from syngas are divided into direct conversion and indirect conversion. The indirect conversion mostly adopts the route of syngas to methanol and then MTO (methanol to olefins), and the direct method can utilize the Fischer-Tropsch synthesis technology, which is one of the efficient routes for directly synthesizing olefins from syngas.

[0003] Fischer-Tropsch synthesis refers to the process of synthesizing various organic substances from syngas under the action of a catalyst, which is divided into high-temperature Fischer-Tropsch (above 300°C) and low-temperature Fischer-Tropsch (200 - 280°C) according to different process conditions. High-temperature Fischer-Tropsch generally uses a fluidized bed reactor (both circulating fluidized bed and fixed fluidized bed) and supporting processes. High-temperature Fischer-Tropsch catalysts mostly use iron-based catalysts. For example, patent CN1695804A introduces a precipitated iron catalyst for fluidized bed, and its products are mainly low-carbon straight-chain hydrocarbons with a carbon number less than 20, such as components of low-carbon olefins and gasoline and diesel fractions. Low-temperature Fischer-Tropsch generally adopts a fixed bed or slurry bed reactor and supporting processes. The catalyst can use a cobalt-based catalyst as introduced in patent CN110252358A or an iron-based catalyst as mentioned in patent CN1113905A, and the products are mainly high-carbon-chain saturated alkanes.

[0004] There are also some attempts to apply a fixed bed reactor to high-temperature Fischer-Tropsch synthesis for producing olefins. However, since Fischer-Tropsch synthesis is a strongly exothermic reaction and the adiabatic temperature rise reaches 1500°C under high-temperature Fischer-Tropsch conditions, when using a fixed bed, it is difficult to remove heat in the reactor, easy to fly temperature, and the catalyst is easy to deactivate. During long-term operation, the CO conversion rate and the selectivity of C2+ olefins will decrease. The fluidized bed can well overcome the heat removal and release problems existing in the fixed bed, but the prior art has the problem of low yield of C4 + α-olefins with high added value. Summary of the Invention

[0005] In order to overcome the problems existing in the prior art, the present invention provides a catalyst for directly synthesizing olefins from syngas, a preparation method thereof, and an application thereof. The active components of the catalyst include iron element, copper element, and element B, wherein B is selected from Eu and / or Gd; the catalyst has a multi-stage pore size, and when the catalyst is applied to directly synthesize olefins from syngas, it has the advantages of high CO conversion rate and high C4 + α-olefin selectivity.

[0006] One of the objectives of the present invention is to provide a catalyst for directly synthesizing olefins from syngas, which comprises a carrier and an active component supported on the carrier, and the active component comprises iron element, copper element and B element, and the B element is selected from Eu element and / or Gd element.

[0007] Among them, the iron element, copper element and B element exist independently in an oxidized state and / or a reduced state.

[0008] In a preferred embodiment, the carrier is selected from at least one of alumina and titanium dioxide.

[0009] In a preferred embodiment, the molar ratio of the iron element to the copper element is 100:(3 - 70), preferably 100:(5 - 50), such as 100:5, 100:10, 100:15, 100:20, 100:25, 100:30, 100:35, 100:40, 100:45 or 100:50.

[0010] In a preferred embodiment, the molar ratio of the iron element to the B element is 100:(0.3 - 7.0), preferably 100:(0.5 - 5), such as 100:0.5, 100:1, 100:1.5, 100:2, 100:2.5, 100:3, 100:3.5, 100:4, 100:4.5 or 100:5.

[0011] In a preferred embodiment, based on the total weight of the carrier and the active component being 100 wt%, the content of the carrier is 20 - 80 wt%, and the content of the active component is 20 - 80 wt%, wherein the weight of the active component is calculated based on the total weight of the iron element, copper element and B element.

[0012] In a further preferred embodiment, based on the total weight of the carrier and the active component being 100 wt%, the content of the carrier is 40 - 60 wt%, and the content of the active component is 40 - 60 wt%, wherein the weight of the active component is calculated based on the total weight of the iron element, copper element and B element.

[0013] For example, based on the total weight of the carrier and the active component being 100 wt%, the content of the carrier is 40 wt%, 45 wt%, 50 wt%, 55 wt% or 60 wt%, and the content of the active component is 40 wt%, 45 wt%, 50 wt%, 55 wt% or 60 wt%, wherein the weight of the active component is calculated based on the total weight of the iron element, copper element and B element.

[0014] In a preferred embodiment, the most probable pore diameter of the catalyst is 2 - 100 nm, preferably 3 - 80 nm (such as 5 - 50 nm).

[0015] In a further preferred embodiment, the catalyst has a multi-stage pore size distribution, preferably a 2-4 stage distribution (such as a 2-stage distribution, 3-stage distribution or 4-stage distribution).

[0016] In an even more preferred embodiment, the catalyst has a three-stage pore size distribution, including: a first-stage pore size with a most probable pore size of 1-10 nm (preferably 3-8 nm), a second-stage pore size with a most probable pore size of 15-35 nm (preferably 18-22 nm), and a third-stage pore size with a most probable pore size of 38-50 nm (preferably 38-42 nm).

[0017] For example, the catalyst has a three-stage pore size, including: a first-stage pore size with a most probable pore size of 1 nm, 2 nm, 4 nm, 5 nm, 6 nm, 8 nm or 10 nm, a second-stage pore size with a most probable pore size of 15 nm, 16 nm, 20 nm, 22 nm, 24 nm, 26 nm, 28 nm, 30 nm, 32 nm, 34 nm or 35 nm, and a third-stage pore size with a most probable pore size of 38, 40, 42, 44, 46, 48 or 50 nm.

[0018] In a preferred embodiment, based on the total volume of the three-stage pore size being 100%, the volume of the first-stage pore size is 10-25%, the volume of the second-stage pore size is 50-70%, and the volume of the third-stage pore size is 10-25%.

[0019] For example, based on the total volume of the three-stage pore size being 100%, the volume of the first-stage pore size is 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24% or 25%, the volume of the second-stage pore size is 50%, 52%, 54%, 56%, 58%, 60%, 62%, 64%, 66%, 68% or 70%, and the volume of the third-stage pore size is 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24% or 25%.

[0020] In a further preferred embodiment, based on the total volume of the three-stage pore size being 100%, the volume of the first-stage pore size is 15-25%, the volume of the second-stage pore size is 50-70%, and the volume of the third-stage pore size is 15-25%.

[0021] In a preferred embodiment, the catalyst is obtained as follows: containing the carrier and the general formula Fe 100 Cu a B bThe catalyst precursor of the active component shown by Ox is obtained through reduction and surface passivation treatment. Among them, B is selected from one of Eu or Gd, the value range of a is 3 - 70, preferably 5 - 50, the value range of b is 0.3 - 7, preferably 0.5 - 5, and x is the total number of oxygen atoms required to satisfy the valence of each element in the catalyst.

[0022] The multi - stage (such as three - stage) pore size structure described in the present invention enables the catalyst to have the advantages of high CO conversion rate and high C4 + α - olefin selectivity when applied to the direct synthesis of olefins from syngas.

[0023] The second object of the present invention is to provide a preparation method of a catalyst for the direct synthesis of olefins from syngas, preferably used for preparing the catalyst for the direct synthesis of olefins from syngas described in the first object of the present invention. The preparation method includes: (1) preparing an aqueous solution containing soluble iron salt, soluble copper salt, soluble salt of B element, and carrier precursor, optionally adjusting the pH, and beating to obtain a slurry; (2) shaping and calcining the slurry to obtain a catalyst precursor; (3) performing reduction and surface passivation treatment on the catalyst precursor to obtain the catalyst.

[0024] In a preferred embodiment, the soluble iron salt is selected from at least one of ferric nitrate, ferric chloride, and ferric citrate.

[0025] In a preferred embodiment, the soluble copper salt is selected from at least one of copper nitrate, copper chloride, and cuprous nitrate.

[0026] In a preferred embodiment, the soluble salt of B element is selected from at least one of nitrate, chloride, and sulfate of B element.

[0027] In a preferred embodiment, the carrier precursor is selected from the carrier and / or the sol containing the carrier, such as at least one of the sol containing SiO2 and the sol containing TiO2.

[0028] In a preferred embodiment, the molar dosage ratio of the soluble iron salt to the soluble copper salt is 100:(3 - 70), preferably 100:(5 - 50), for example, 100:5, 100:10, 100:15, 100:20, 100:25, 100:30, 100:35, 100:40, 100:45, or 100:50. The molar dosages of the soluble iron salt and the soluble copper salt are calculated based on the molar amounts of iron element and copper element respectively.

[0029] In a preferred embodiment, the molar dosage ratio of the soluble iron salt to the soluble salt of element B is 100:(0.3 - 7), preferably 100:(0.5 - 5), for example, 100:0.5, 100:1, 100:1.5, 100:2, 100:2.5, 100:3, 100:3.5, 100:4, 100:4.5 or 100:5. The molar dosages of the soluble iron salt and the soluble copper salt of element B are based on the molar amounts of iron element and element B, respectively.

[0030] In a preferred embodiment, based on the total amount of 100 parts by weight of iron element in the soluble iron salt, copper element in the soluble copper salt, element B in the soluble salt of element B, and the carrier in the carrier precursor, the amount of the carrier in the carrier precursor is 20 - 80 parts by weight, preferably 40 - 60 parts by weight, and the total amount of iron element in the soluble iron salt, copper element in the soluble copper salt, and element B in the soluble salt of element B is 20 - 80 parts by weight, preferably 40 - 60 parts by weight.

[0031] In the above definitions, the dosage of the soluble iron salt is based on the weight of iron element therein, the dosage of the soluble copper salt is based on the weight of copper element therein, the dosage of the soluble salt of element B is based on the weight of element B therein, and the dosage of the carrier precursor is based on the weight of the carrier therein (for example, the dosage of the sol containing SiO2 is based on the dosage of SiO2, and the dosage of the sol containing TiO2 is based on the dosage of TiO2).

[0032] In a preferred embodiment, the temperature of the pulping in step (1) is 60 - 110°C, preferably 78 - 98°C, for example, 60°C, 70°C, 72°C, 75°C, 78°C, 80°C, 82°C, 85°C, 88°C, 90°C, 92°C, 95°C, 98°C, 100°C or 110°C.

[0033] In a preferred embodiment, the solid content of the slurry in step (1) is 10 - 60 wt%, preferably 15 - 45 wt%, for example, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt% or 60 wt%.

[0034] In a preferred embodiment, step (1) includes: (1.1) preparing a mixed aqueous solution I containing a soluble iron salt and a soluble copper salt, and preparing a soluble salt solution containing element B; (1.2) mixing the carrier and / or its sol with the mixed aqueous solution I, and adjusting the pH to 1 - 5 (for example, 1, 2, 3, 4 or 5) to obtain a mixed aqueous solution II; (1.3) mixing the soluble salt solution containing element B with the mixed aqueous solution II, and pulping to obtain a slurry.

[0035] In a preferred embodiment, the forming in step (2) is carried out by spray drying.

[0036] In a further preferred embodiment, the spray drying is carried out in a spray dryer, the inlet temperature of the spray dryer is 280 - 380 °C, and the outlet temperature is 150 - 250 °C.

[0037] For example, the spray drying is carried out in a spray dryer, the inlet temperature of the spray dryer is 280 °C, 300 °C, 320 °C, 340 °C, 360 °C or 380 °C, and the outlet temperature is 150 °C, 160 °C, 180 °C, 200 °C, 220 °C, 240 °C or 250 °C.

[0038] In a still further preferred embodiment, the spray drying is carried out in a spray dryer, the inlet temperature of the spray dryer is 300 - 350 °C, and the outlet temperature is 170 - 220 °C.

[0039] In a preferred embodiment, the roasting in step (2) is carried out in two steps: first roasting in an air atmosphere, and then roasting in a mixed atmosphere of air and oxygen.

[0040] In a further preferred embodiment, the roasting in step (2) is carried out in two steps: first roasting at 300 - 400 °C in an air atmosphere for 0.5 - 5 h, and then roasting at 500 - 700 °C in a mixed atmosphere of air and oxygen for 0.2 - 2 h.

[0041] For example, the roasting in step (2) is carried out in two steps: first roasting at 300 °C, 320 °C, 340 °C, 360 °C, 380 °C or 400 °C in an air atmosphere for 0.5 h, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h or 5 h, and then roasting at 500 °C, 550 °C, 600 °C, 650 °C or 700 °C in a mixed atmosphere of air and oxygen for 0.2 h, 0.5 h, 0.8 h, 1 h, 1.2 h, 1.5 h, 1.8 h or 2 h.

[0042] The inventors found through a large number of experiments that adopting the above roasting method is helpful for the formation of pore structures.

[0043] In a still further preferred embodiment, in the mixed atmosphere of air and oxygen, the volume ratio of oxygen to air is (10 - 30):100, for example, 10:100, 15:100, 20:100, 25:100 or 30:100.

[0044] In a preferred embodiment, the reduction in step (3) is carried out in a mixed atmosphere of hydrogen and a protective gas. Preferably, the volume ratio of hydrogen to the protective gas is (10 - 50):100. More preferably, the protective gas is selected from at least one of nitrogen and inert gases, such as nitrogen and / or helium.

[0045] For example, the volume ratio of hydrogen to the protective gas is 10:100, 15:100, 20:100, 25:100, 30:100, 35:100, 40:100, 45:100 or 50:100.

[0046] In a further preferred embodiment, the conditions for the reduction in step (3) include: a temperature of 400 - 500 °C and a time of 4 - 24 h.

[0047] For example, the conditions for the reduction include: a temperature of 400 °C, 420 °C, 440 °C, 460 °C, 480 °C or 500 °C, and a time of 4 h, 5 h, 10 h, 15 h, 20 h or 24 h.

[0048] In a preferred embodiment, the surface passivation treatment in step (3) is carried out in a mixed atmosphere of air and a protective gas. Preferably, the volume ratio of air to the protective gas is (2 - 20):100, preferably (4 - 10):100. More preferably, the protective gas is selected from at least one of nitrogen and inert gases, such as nitrogen and / or helium.

[0049] For example, the volume ratio of air to the protective gas is 2:100, 5:100, 8:100, 10:100, 12:100, 15:100, 18:100 or 20:100.

[0050] In a further preferred embodiment, the conditions for the surface passivation treatment in step (3) include: a temperature from room temperature to 100 °C and a time of 4 - 24 h. Herein, the room temperature is 25 ± 5 °C.

[0051] For example, the conditions for the surface passivation treatment in step (3) include: a temperature of room temperature, 40 °C, 50 °C, 60 °C, 70 °C, 80 °C, 90 °C or 100 °C, and a time of 4 h, 5 h, 10 h, 15 h, 20 h or 24 h.

[0052] The third object of the present invention is to provide a catalyst obtained by using the preparation method described in the second object of the present invention.

[0053] The fourth object of the present invention is to provide the application of the catalyst described in the first object of the present invention or the catalyst obtained by using the preparation method described in the second object of the present invention in the direct synthesis of olefins from syngas.

[0054] A fifth object of the present invention is to provide a method for directly preparing olefins from syngas, comprising: reacting syngas in the presence of a catalyst, wherein the catalyst is selected from the catalysts described in one of the objects of the present invention or the catalysts obtained by using the preparation method described in the second object of the present invention.

[0055] Preferably, the syngas is a mixture of CO and hydrogen, wherein the molar ratio of CO to hydrogen is 1:(1-4), for example, 1:1, 1:2, 1:3 or 1:4.

[0056] More preferably, the reaction conditions include: a temperature of 300-380°C, a pressure of 0.8-8.0 MPa, and a catalyst load (standard volume hourly space velocity) of 3000-30000 h -1 .

[0057] For example, the reaction conditions include: a temperature of 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, 360°C, 370°C or 380°C, a pressure of 0.8 MPa, 1 MPa, 1.5 MPa, 2 MPa, 2.5 MPa, 3 MPa, 3.5 MPa, 4 MPa, 4.5 MPa, 5 MPa, 5.5 MPa, 6 MPa, 6.5 MPa, 7 MPa, 7.5 MPa or 8.0 MPa, and a catalyst load (standard volume hourly space velocity) of 3000 h -1 , 5000 h -1 , 10000 h -1 , 15000 h -1 , 20000 h -1 , 25000 h -1 or 30000 h -1 .

[0058] In the ranges disclosed in the present invention, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein. In the following text, in principle, various technical solutions can be combined with each other to obtain new technical solutions, which should also be regarded as specifically disclosed herein.

[0059] Compared with the prior art, the present invention has the following beneficial effects: the active components in the catalyst include iron element, copper element and B element, wherein B is selected from Eu and / or Gd; the catalyst has a multi-stage (for example, three-stage) pore size, and the catalyst has high CO conversion rate and high C4 + α-olefin selectivity when applied to directly preparing olefins from syngas. Detailed implementation manners

[0060] The present invention will be specifically described below in conjunction with specific embodiments. It is necessary to point out here that the following embodiments are only used for further illustration of the present invention and cannot be construed as limiting the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention still fall within the protection scope of the present invention.

[0061] In addition, it should be noted that the various specific technical features described in the following specific implementation manners can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0062] In addition, any combination can be made between various different embodiments of the present invention as long as it does not violate the idea of the present invention. The technical solutions thus formed belong to a part of the original public content of this specification and also fall within the protection scope of the present invention.

[0063] If the raw materials used in the examples and comparative examples are not specifically limited, they are all disclosed in the prior art. For example, they can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0064]

Example 1

[0065] 1 mol of Fe(NO3)3·9H2O and 0.1 mol of Cu(NO3)2·3H2O were dissolved in water to form solution I with a concentration of 40 wt%. 226 g of 40 wt% SiO2 sol was mixed with solution I, and a small amount of dilute nitric acid was added to adjust the pH value of the slurry to 2 to obtain mixture II. 0.025 mol of Gd(NO3)3·6H2O was dissolved in water to form solution III with a concentration of 40 wt%. Solution III was added to mixture II, and the mixture was stirred and slurried in a water bath at 90 °C for 1 h to obtain slurry IV with a solid content of 40 wt%. The slurry was spray-dried and formed. The inlet temperature of the spray dryer was 320 °C, and the outlet temperature was 190 °C to obtain the spray-dried material. The spray-dried material was first calcined at 350 °C for 1 h in an air atmosphere, and then calcined at 650 °C for 0.5 h in an oxygen-rich atmosphere with an oxygen:air ratio of 15:100 to obtain microspherical particles. The microspherical particles were first reduced at 450 °C for 18 h in an atmosphere with a hydrogen:nitrogen ratio of 20:100, and then surface passivated at 40 °C for 8 h in an atmosphere with an air:nitrogen ratio of 7:100 to obtain the catalyst. The composition of the catalyst before reduction after calcination was 50 wt% Fe 100 Cu 10 Gd 2.5Ox + 50 wt% SiO₂. The final formed catalyst characterized by BET adsorption and desorption instrument has three most probable pore size distributions: the first - stage pore size with the most probable pore size of 5.0 nm, the second - stage pore size with the most probable pore size of 20.0 nm, and the third - stage pore size with the most probable pore size of 40.0 nm. Calculated according to the integral area of each stage of pore size and the total integral area, the volume of the first - stage pore size accounts for 20%, the volume of the second - stage pore size accounts for 60%, and the volume of the third - stage pore size accounts for 20%. Based on the total weight of the carrier and the active component being 100 wt%, the carrier is 57.7 wt%, and the active component is 42.3 wt%, where the weight of the active component is calculated based on the total weight of Fe, Cu, and Gd elements.

[0066] The evaluation conditions for the catalyst synthesis reaction are: reaction temperature 350 °C

[0067] Reaction pressure 1.1 MPa

[0068] Catalyst load (standard volume space velocity) 4000 h⁻¹ -1

[0069] The raw material ratio (mole) in syngas CO / H₂ = 1:2

[0070] The initial activity calibration time of the catalyst is 100 h after feeding.

[0071]

Example 2

[0072] Dissolve 1 mol of Fe(NO₃)₃·9H₂O and 0.03 mol of Cu(NO₃)₂·3H₂O in water to make solution Ⅰ with a concentration of 40 wt%; mix 236 g of 40 wt% TiO₂ sol and solution Ⅰ, and add a small amount of dilute nitric acid to adjust the pH value of the slurry to 2 to obtain mixed solution Ⅱ; dissolve 0.07 mol of Gd(NO₃)₃·6H₂O in water to make solution Ⅲ with a concentration of 40 wt%; add solution Ⅲ to mixed solution Ⅱ, and stir and beat the slurry in a water bath at 90 °C for 1 h to obtain slurry Ⅳ with a solid content of 40 wt%; spray - dry and form slurry Ⅳ, with the inlet temperature of the spray dryer being 320 °C and the outlet temperature being 190 °C, to obtain the spray - dried material; first calcine the spray - dried material in an air atmosphere at 300 °C for 5 h, and then calcine it in an oxygen - rich atmosphere with oxygen:air = 10:100 at 750 °C for 1 h to obtain micro - spherical particles; first reduce the micro - spherical particles in an atmosphere of hydrogen:nitrogen = 50:100 at 500 °C for 10 h, and then passivate the surface at 30 °C in an atmosphere of air:nitrogen = 10:100 for 8 h to obtain the catalyst. The composition of the catalyst before reduction after calcination is 50 wt% Fe 100 Cu₃Gd₇O x+50 wt% SiO₂. The final formed catalyst is characterized by BET adsorption and desorption instrument, and the catalyst has three most probable pore size distributions: the most probable pore size is 4.8 nm, the second stage pore size with the most probable pore size of 20.3 nm, and the third stage pore size with the most probable pore size of 39.6 nm. Calculated according to the integral area of each stage pore size and the total integral area, the volume of the first stage pore size accounts for 15%, the volume of the second stage pore size accounts for 70%, and the volume of the third stage pore size accounts for 15%. Based on the total weight of the carrier and the active component being 100 wt%, the carrier is 57.8 wt%, and the active component is 42.2 wt%, where the weight of the active component is based on the total weight of Fe, Cu, and Gd elements.

[0073] The evaluation conditions for the catalyst synthesis reaction are: reaction temperature 350 °C

[0074] Reaction pressure 1.1 MPa

[0075] Catalyst load (standard volume space velocity) 4000 h⁻¹ -1

[0076] The raw material ratio (mole) in the syngas is CO / H₂ = 1:2

[0077] The initial activity calibration time of the catalyst is 100 h after feeding.

[0078]

Example 3

[0079] Dissolve 1 mol of Fe(NO₃)₃·9H₂O and 0.7 mol of Cu(NO₃)₂·3H₂O in water to make solution Ⅰ with a concentration of 40 wt%; mix 227 g of 40 wt% SiO₂ sol and solution Ⅰ, and add a small amount of dilute nitric acid to adjust the pH value of the slurry to 2 to obtain mixture Ⅱ; dissolve 0.003 mol of Gd(NO₃)₃·6H₂O in water to make solution Ⅲ with a concentration of 40 wt%; add solution Ⅲ to mixture Ⅱ, and stir and beat the slurry in a water bath at 90 °C for 1 h to obtain slurry Ⅳ with a solid content of 40 wt%; spray-dry and form slurry Ⅳ, with the inlet temperature of the spray dryer being 320 °C and the outlet temperature being 190 °C, to obtain the spray-dried material; first calcine the spray-dried material in an air atmosphere at 400 °C for 0.5 h, and then calcine it in an oxygen-rich atmosphere with oxygen:air = 30:100 at 500 °C for 2 h to obtain microspherical particles; first reduce the microspherical particles in a hydrogen:nitrogen = 10:100 atmosphere at 400 °C for 24 h, and then passivate the surface in an air:nitrogen = 2:100 atmosphere at 100 °C for 4 h to obtain the catalyst. The composition of the catalyst before reduction after calcination is 60 wt% Fe 100 Cu 70 Gd 0.3Ox + 40 wt% SiO2. The final formed catalyst is characterized by BET adsorption and desorption instrument, and the catalyst has three most probable pore size distributions: the first-stage pore size with the most probable pore size of 3.9 nm, the second-stage pore size with the most probable pore size of 20.8 nm, and the third-stage pore size with the most probable pore size of 41.5 nm. Calculated according to the integral area of each stage of pore size and the total integral area, the volume of the first-stage pore size accounts for 23%, the volume of the second-stage pore size accounts for 52%, and the volume of the third-stage pore size accounts for 25%. Based on the total weight of the carrier and the active component being 100 wt%, the carrier is 47.3 wt%, and the active component is 52.7 wt%, where the weight of the active component is based on the total weight of Fe, Cu, and Gd elements.

[0080] The evaluation conditions for the catalyst synthesis reaction are: reaction temperature 350 °C

[0081] Reaction pressure 1.1 MPa

[0082] Catalyst load (standard volume space velocity) 4000 h-1 -1

[0083] The raw material ratio (mole) in syngas CO / H2 = 1:2

[0084] The initial activity calibration time of the catalyst is 100 h after feeding.

[0085]

Example 4

[0086] Dissolve 1 mol of Fe(NO3)3·9H2O and 0.1 mol of Cu(NO3)2·3H2O in water to make solution I with a concentration of 40 wt%; mix 126 g of 40 wt% SiO2 sol, 100 g of 40 wt% TiO2 sol and solution I, and add a small amount of dilute nitric acid to adjust the pH value of the slurry to 2 to obtain mixture II; dissolve 0.025 mol of Gd(NO3)3·6H2O in water to make solution III with a concentration of 40 wt%; add solution III to mixture II, and stir and beat in a water bath at 90 °C for 1 h to obtain slurry IV, and the solid content of slurry IV is 40 wt%; spray-dry and form the slurry, the inlet temperature of the spray dryer is 320 °C, and the outlet temperature is 190 °C to obtain the spray-dried material; first calcine the spray-dried material in air atmosphere at 350 °C for 1 h, and then calcine it in an oxygen:air = 10:100 oxygen-rich atmosphere at 650 °C for 0.5 h to obtain microspherical particles; first reduce the microspherical particles in a hydrogen:nitrogen = 20:100 atmosphere at 450 °C for 18 h, and then passivate the surface in an air:nitrogen = 7:100 atmosphere at 40 °C for 8 h to obtain the catalyst. The composition of the catalyst before reduction after calcination is 50 wt% Fe 100 Cu 10 Gd 2.5Ox + 40 wt% SiO2 + 10 wt% TiO2. The final shaped catalyst is characterized by BET adsorption and desorption instrument, and the catalyst has three most probable pore size distributions: the first-stage pore size with the most probable pore size of 5.2 nm, the second-stage pore size with the most probable pore size of 21.2 nm, and the third-stage pore size with the most probable pore size of 39.5 nm. According to the calculation of the integral area of each stage of pore size and the total integral area, the volume of the first-stage pore size accounts for 21%, the volume of the second-stage pore size accounts for 65%, and the volume of the third-stage pore size accounts for 14%. Based on the total weight of the carrier and the active component being 100 wt%, the carrier is 57.67 wt%, and the active component is 42.33 wt%, where the weight of the active component is calculated based on the total weight of Fe, Cu, and Gd elements.

[0087] The evaluation conditions for the catalyst synthesis reaction are: reaction temperature 350 °C

[0088] Reaction pressure 1.1 MPa

[0089] Catalyst load (standard volume hourly space velocity) 4000 h-1 -1

[0090] The raw material ratio (mole) in the syngas CO / H2 = 1:2

[0091] The initial activity calibration time of the catalyst is 100 h after feeding.

[0092]

Example 5

[0093] Dissolve 1 mol of Fe(NO3)3·9H2O and 0.1 mol of Cu(NO3)2·3H2O in water to make solution I with a concentration of 40 wt%; mix 226 g of 40 wt% SiO2 sol and solution I, and add a small amount of dilute nitric acid to adjust the pH value of the slurry to 2 to obtain mixture II; dissolve 0.025 mol of Eu(NO3)3·6H2O in water to make solution III with a concentration of 40 wt%; add solution III to mixture II, and stir and beat in a water bath at 90 °C for 1 h to obtain slurry IV with a solid content of 40 wt%; spray-dry the slurry to form a shape, with the inlet temperature of the spray dryer being 320 °C and the outlet temperature being 190 °C, to obtain the spray-dried material; first calcine the spray-dried material in an air atmosphere at 350 °C for 1 h, and then calcine it in an oxygen-rich atmosphere with oxygen:air = 15:100 at 650 °C for 0.5 h to obtain microspherical particles; first reduce the microspherical particles in a hydrogen:nitrogen = 20:100 atmosphere at 450 °C for 18 h, and then passivate the surface at 40 °C in an air:nitrogen = 7:100 atmosphere for 8 h to obtain the catalyst. The composition of the catalyst before reduction after calcination is 50 wt% Fe 100 Cu 10 Eu 2.5Ox + 50 wt% SiO₂. The final formed catalyst has three most probable pore size distributions as characterized by a BET adsorption and desorption instrument: a first-stage pore size with a most probable pore size of 4.8 nm, a second-stage pore size with a most probable pore size of 20.4 nm, and a third-stage pore size with a most probable pore size of 40.9 nm. Calculated based on the integral area of each stage of pore size and the total integral area, the volume of the first-stage pore size accounts for 10%, the volume of the second-stage pore size accounts for 68%, and the volume of the third-stage pore size accounts for 22%. Based on the total weight of the carrier and the active component being 100 wt%, the carrier is 57.73 wt%, and the active component is 42.27 wt%. Among them, the weight of the active component is calculated based on the total weight of Fe, Cu, and Eu elements.

[0094] The evaluation conditions for the catalyst synthesis reaction are: reaction temperature 350 °C

[0095] Reaction pressure 1.1 MPa

[0096] Catalyst load (standard volume space velocity) 4000 h⁻¹ -1

[0097] The raw material ratio (mole) in the syngas is CO / H₂ = 1:2

[0098] The initial activity calibration time of the catalyst is 100 h after feeding.

[0099]

Example 6

[0100] Dissolve 1 mol of Fe(NO₃)₃·9H₂O and 0.1 mol of Cu(NO₃)₂·3H₂O in water to make solution Ⅰ with a concentration of 40 wt%; mix 226 g of 40 wt% SiO₂ sol and solution Ⅰ, and add a small amount of dilute nitric acid to adjust the pH value of the slurry to 2 to obtain mixture Ⅱ; dissolve 0.025 mol of Gd(NO₃)₃·6H₂O in water to make solution Ⅲ with a concentration of 40 wt%; add solution Ⅲ to mixture Ⅱ, and stir and beat the slurry in a water bath at 90 °C for 1 h to obtain slurry Ⅳ with a solid content of 40 wt%; spray-dry and form slurry Ⅳ, with the inlet temperature of the spray dryer being 320 °C and the outlet temperature being 190 °C, to obtain the spray-dried material; first calcine the spray-dried material in an air atmosphere at 350 °C for 1 h, and then calcine it in an oxygen-rich atmosphere with oxygen:air = 15:100 at 650 °C for 0.5 h to obtain microspherical particles; passivate the surface of the microspherical particles in an atmosphere of air:nitrogen = 7:100 at 40 °C for 8 h to obtain the catalyst. The composition of the catalyst before passivation after calcination is 50 wt% Fe 100 Cu 10 Gd 2.5 O x+50 wt% SiO₂, and the pore distribution of the finally formed catalyst characterized by BET adsorption and desorption instrument is a most probable particle size distribution of 20 nm.

[0101] The evaluation conditions for the catalyst synthesis reaction are: reaction temperature 350 °C

[0102] Reaction pressure 1.1 MPa

[0103] Catalyst load (standard volume space velocity) 4000 h⁻¹ -1

[0104] The raw material ratio (mole) in the syngas is CO / H₂ = 1:2

[0105] The initial activity calibration time of the catalyst is 100 h after feeding.

[0106]

Example 7

[0107] Dissolve 1 mol of Fe(NO₃)₃·9H₂O and 0.1 mol of Cu(NO₃)₂·3H₂O in water to make solution Ⅰ with a concentration of 40 wt%; mix 226 g of 40 wt% SiO₂ sol and solution Ⅰ, and add a small amount of dilute nitric acid to adjust the pH value of the slurry to 2 to obtain mixed solution Ⅱ; dissolve 0.025 mol of Gd(NO₃)₃·6H₂O in water to make solution Ⅲ with a concentration of 40 wt%; add solution Ⅲ to mixed solution Ⅱ, and stir and beat the slurry in a water bath at 90 °C for 1 h to obtain slurry Ⅳ with a solid content of 40 wt%; spray-dry and form slurry Ⅳ, with the inlet temperature of the spray dryer being 320 °C and the outlet temperature being 190 °C, to obtain the spray-dried material; first calcine the spray-dried material in an air atmosphere at 350 °C for 1 h, and then calcine it in an air atmosphere at 650 °C for 0.5 h to obtain microspherical particles; first reduce the microspherical particles in a hydrogen:nitrogen = 20:100 atmosphere at 450 °C for 18 h, and then passivate the surface at 40 °C in an air:nitrogen = 7:100 atmosphere for 8 h to obtain the catalyst. The composition of the catalyst before reduction after calcination is 50 wt% Fe 100 Cu 10 Gd 2.5 Ox + 50 wt% SiO₂, and the pore distribution of the finally formed catalyst characterized by BET adsorption and desorption instrument is two most probable particle size distributions of 5 nm and 20 nm.

[0108] The evaluation conditions for the catalyst synthesis reaction are: reaction temperature 350 °C

[0109] Reaction pressure 1.1 MPa

[0110] Catalyst load (standard volume space velocity) 4000 h⁻¹ -1

[0111] The raw material ratio (molar) in syngas is CO / H2 = 1:2

[0112] The initial activity calibration time of the catalyst is 100 h after feeding the raw materials.

[0113]

Comparative Example 1

[0114] Dissolve 1 mol of Fe(NO3)3·9H2O and 0.1 mol of Cu(NO3)2·3H2O in water to make solution I with a concentration of 40 wt%; mix 226 g of 40 wt% SiO2 sol and solution I, add a small amount of dilute nitric acid to adjust the pH value of the slurry to 2 to obtain mixture II; stir and beat the slurry in a water bath at 90 °C for 1 h to obtain a slurry with a solid content of 40 wt%; spray-dry the slurry to form particles, with the inlet temperature of the spray dryer being 320 °C and the outlet temperature being 190 °C, to obtain the spray-dried material; first calcine the spray-dried material in an air atmosphere at 350 °C for 1 h, and then calcine it in an oxygen-rich atmosphere with an oxygen:air ratio of 15:100 at 650 °C for 0.5 h to obtain microspherical particles; reduce the microspherical particles in a hydrogen:nitrogen atmosphere with a ratio of 20:100 at 450 °C for 18 h, and then passivate the surface in an air:nitrogen atmosphere with a ratio of 7:100 at 40 °C for 8 h to obtain the catalyst. The composition of the catalyst before reduction after calcination is 50 wt% Fe 100 Cu 10 O x + 50 wt% SiO2. The finally formed catalyst characterized by a BET adsorption and desorption instrument has two most probable pore size distributions: the first-order pore size with a most probable pore size of 10.0 nm and the second-order pore size with a most probable pore size of 30.0 nm. According to the integral area of each pore size and the total integral area, the volume of the first-order pore size accounts for 40%, and the volume of the second-order pore size accounts for 60%.

[0115] The evaluation conditions for the catalyst synthesis reaction are: reaction temperature 350 °C

[0116] Reaction pressure 1.1 MPa

[0117] Catalyst load (standard volume space velocity) 4000 h−1 -1

[0118] The raw material ratio (molar) in syngas is CO / H2 = 1:2

[0119] The initial activity calibration time of the catalyst is 100 h after feeding the raw materials.

[0120] Table 1: Reaction results

[0121]

[0122] The C4 + α-olefins in Table 1 refer to α-olefins with 4 or more carbon atoms (including C4).

[0123] As can be seen from Table 1, the catalyst of the present invention has the advantages of high CO conversion rate and high selectivity for C4 + α-olefins. Especially when the catalyst has a three-level pore size, the effect is more excellent.

[0124] The present invention has been described in detail above in combination with specific embodiments and exemplary examples, but these descriptions should not be construed as limiting the present invention. Those skilled in the art understand that without departing from the spirit and scope of the present invention, various equivalent substitutions, modifications or improvements can be made to the technical solutions and their implementation manners of the present invention, and these all fall within the scope of the present invention. The protection scope of the present invention is subject to the appended claims.

Claims

1. A catalyst for directly preparing olefins from syngas, which comprises a carrier and an active component supported on the carrier, the active component comprises iron element, copper element and element B, and element B is selected from Eu element and / or Gd element, wherein, The molar ratio of iron element to copper element is 100:(3 - 70), and the molar ratio of iron element to B element is 100:(0.3 - 7.0).

2. The catalyst according to claim 1, wherein the molar ratio of iron element to copper element is 100:(5 - 50), and / or the molar ratio of iron element to B element is 100:(0.5 - 5).

3. The catalyst according to claim 1, wherein the carrier is selected from at least one of alumina and titanium dioxide; and / or calculated based on the total weight of the carrier and the active component being 100 wt%, the content of the carrier is 20 - 80 wt%, and the content of the active component is 20 - 80 wt%; more preferably, calculated based on the total weight of the carrier and the active component being 100 wt%, the content of the carrier is 40 - 60 wt%, and the content of the active component is 40 - 60 wt%, wherein the weight of the active component is calculated based on the total weight of iron element, copper element, and B element.

4. The catalyst according to any one of claims 1 to 3, characterized in that, The most probable pore diameter of the catalyst is 2 - 100 nm, preferably 3 - 80 nm; Preferably, the pore diameters of the catalyst are distributed in multiple levels, preferably 2 - 4 levels; More preferably, the catalyst has a three - level pore diameter distribution, including: a first - level pore diameter with a most probable pore diameter of 1 - 10 nm, a second - level pore diameter with a most probable pore diameter of 15 - 35 nm, and a third - level pore diameter with a most probable pore diameter of 38 - 50 nm.

5. A preparation method of a catalyst for directly preparing olefins from syngas, preferably for preparing the catalyst according to any one of claims 1 to 4, the preparation method comprising: (1) Prepare an aqueous solution containing soluble iron salt, soluble copper salt, soluble salt of B element, and carrier precursor, optionally adjust the pH, and beat to obtain a slurry; (2) Shape and calcine the slurry to obtain a catalyst precursor; (3) Reduce and perform surface passivation treatment on the catalyst precursor to obtain the catalyst.

6. The preparation method according to claim 5, characterized in that, The soluble iron salt is selected from at least one of iron nitrate, iron chloride, and iron citrate; and / or, the soluble copper salt is selected from at least one of copper nitrate, copper chloride, and cuprous nitrate; and / or, the soluble salt of B element is selected from at least one of nitrate, chloride, and sulfate of B element; and / or, the carrier precursor is selected from the carrier and / or the sol containing the carrier.

7. The preparation method according to claim 5, wherein the molar dosage ratio of the soluble iron salt to the soluble copper salt is 100:(3 - 70), preferably 100:(5 - 50), and the molar dosages of the soluble iron salt and the soluble copper salt are calculated based on the molar amounts of iron element and copper element respectively; and / or the molar dosage ratio of the soluble iron salt to the soluble salt of B element is 100:(0.3 - 7), preferably 100:(0.5 - 5), and the molar dosages of the soluble iron salt and the soluble copper salt of B element are calculated based on the molar amounts of iron element and B element respectively; and / or Based on the total amount of the carrier in the carrier precursor being 100 parts by weight, the amount of the carrier in the carrier precursor is 20 - 80 parts by weight, preferably 40 - 60 parts by weight, and the total amount of iron element in the soluble iron salt, copper element in the soluble copper salt, and B element in the soluble salt of B element is 20 - 80 parts by weight, preferably 40 - 60 parts by weight.

8. The preparation method according to claim 5, characterized in that the temperature of the pulping in step (1) is 60 - 110 °C, preferably 78 - 98 °C; and / or spray drying is used for the shaping in step (2); and / or the calcination in step (2) is carried out in two steps: first calcined in an air atmosphere, and then calcined in a mixed atmosphere of air and oxygen; preferably, the calcination in step (2) is carried out in two steps: first calcined at 300 - 400 °C in an air atmosphere for 0.5 - 5 h, and then calcined at 500 - 700 °C in a mixed atmosphere of air and oxygen for 0.2 - 2 h.

9. The preparation method according to any one of claims 5 - 8, characterized in that the reduction in step (3) is carried out in a mixed atmosphere of hydrogen and a protective gas. Preferably, the volume ratio of hydrogen to the protective gas is (10 - 50):

100. More preferably, the protective gas is selected from at least one of nitrogen and inert gases; and / or the conditions of the reduction in step (3) include: the temperature is 400 - 500 °C and the time is 4 - 24 h; and / or the surface passivation treatment in step (3) is carried out in a mixed atmosphere of air and a protective gas. Preferably, the volume ratio of air to the protective gas is (2 - 20):100, preferably (4 - 10):100; more preferably, the protective gas is selected from at least one of nitrogen and inert gases.

10. A catalyst obtained by using the preparation method according to any one of claims 5 - 9.

11. Application of the catalyst according to any one of claims 1 - 4 or the catalyst obtained by using the preparation method according to any one of claims 5 - 9 in the direct synthesis of olefins from syngas.

12. A method for directly preparing olefins from syngas, comprising: The syngas reacts in the presence of a catalyst, wherein the catalyst is selected from the catalyst according to any one of claims 1 - 4 or the catalyst obtained by using the preparation method according to any one of claims 5 - 9; Preferably, the syngas is a mixture of CO and hydrogen, wherein the molar ratio of CO to hydrogen is 1:(1 - 4); Preferably, the conditions of the reaction include: temperature of 300 to 380 °C, pressure of 0.8 to 8.0 MPa, and catalyst loading of 3000 to 30000 h -1 .

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