A catalyst for the synthesis of olefins from syngas, its preparation method and application.

Abstract

This invention discloses a catalyst for the synthesis of olefins from syngas, its preparation method, and its application. The catalyst, by weight, comprises A) 50-80 parts of a support; B) 20-50 parts of an active component, the active component containing a composition with the following chemical formula on an atomic basis: Co 100 Mn a K 2b Fe b O x The value of 'a' ranges from 30 to 60; the value of 'b' ranges from 1 to 10; and 'x' represents the total number of oxygen atoms required to satisfy the oxidation states of all elements in the catalyst. This catalyst is suitable for the preparation of α-olefins from syngas and has the advantage of high olefin content, especially high α-olefin content, in the product.

Description

Technical Field

[0001] This invention belongs to the field of syngas-to-olefins production, specifically relating to a catalyst for syngas-to-olefins production, its preparation method, and its application. Background Technology

[0002] Fischer-Tropsch synthesis technology refers to the process in which syngas (CO and H2) undergoes a Fischer-Tropsch reaction under the action of a catalyst to produce a mixture of various organic products, water, and CO2. It is an important route for the indirect liquefaction of coal / natural gas to produce fuel oil or chemicals.

[0003] The distribution of organic matter in the products varies depending on the catalyst and the corresponding synthesis conditions. Generally, cobalt-based catalysts are suitable for Fischer-Tropsch synthesis at lower temperatures (200–280°C), producing mainly high-carbon-chain saturated hydrocarbons, primarily used in the synthesis of diesel oil and Fischer-Tropsch wax. CN110252358A describes a cobalt catalyst, its preparation method, and a method for Fischer-Tropsch wax synthesis. Iron-based catalysts can be used in Fischer-Tropsch synthesis at lower temperatures (200–280°C) to produce high-carbon-chain oils and waxes, similar to cobalt-based catalysts, and can also be used in Fischer-Tropsch synthesis at higher temperatures (above 300°C), producing mainly low-carbon-chain unsaturated hydrocarbons. Patent CN 106607059A discloses an Fe-Mn catalyst for the direct preparation of low-carbon olefins from syngas and its preparation method.

[0004] α-olefins refer to monoolefins with double bonds at the ends of their molecular chains. Industrially, they generally refer specifically to straight-chain α-olefins with four or more carbon atoms. There are many methods for preparing α-olefins, one of which is the Fischer-Tropsch synthesis process. This process involves pre-separation, selective hydrogenation, water washing, etherification, methanol recovery, superdistillation, drying, and refining of Fischer-Tropsch oil rich in α-olefins to obtain high-quality α-olefins. The amount of α-olefins in the products of high-temperature Fischer-Tropsch technology is significantly greater than that in low-temperature Fischer-Tropsch technology. Intermediates used in subsequent Fischer-Tropsch synthesis of α-olefins are generally derived from high-temperature Fischer-Tropsch technology using iron-based catalysts.

[0005] Existing catalysts for the production of α-olefins from syngas generally suffer from low olefin yields. Therefore, developing a catalyst suitable for the production of α-olefins from syngas has always been a research direction in this field. Summary of the Invention

[0006] To address the problem of low olefin yield in Fischer-Tropsch synthesis products using cobalt-based catalysts in existing technologies, this invention provides a cobalt-based catalyst for the preparation of α-olefins from syngas, its preparation method, and its application. The catalyst is suitable for the preparation of α-olefins from syngas, and is particularly suitable for the conversion of hydrogen-rich syngas containing a considerable amount of CO2 using a high-temperature Fischer-Tropsch process. It has the advantage of high olefin content, especially high α-olefin content, in the products.

[0007] A first aspect of the present invention provides a catalyst for the preparation of olefins from syngas, wherein the catalyst, by weight, comprises:

[0008] A) 50–80 copies of the carrier;

[0009] B) 20–50 parts of active ingredient, the active ingredient containing a composition with the following chemical formula in atomic ratio:

[0010] Co 100 Mn a K 2b Fe b O x

[0011] The value of a ranges from 30 to 60;

[0012] The value of b ranges from 1 to 10;

[0013] x represents the total number of oxygen atoms required to satisfy the oxidation states of all elements in the catalyst.

[0014] According to the present invention, the support comprises at least one of oxides of Al and Zr.

[0015] According to the present invention, the catalyst is microsphere-shaped.

[0016] According to the present invention, based on XPS characterization results, the molar ratio of K to Fe on the catalyst surface is K:Fe = 0.3 to 1.3:1, preferably 0.5 to 1.1:1.

[0017] A second aspect of the present invention provides a method for preparing the above-mentioned catalyst, the method comprising the following steps:

[0018] The catalyst was obtained by mixing a mixture of Co and Mn salts, a support, and K2FeO4, followed by spray drying and calcination.

[0019] According to the present invention, the pH of the pulp can be adjusted during mixing and pulping. Preferably, the pH is 1 to 5. The pH of the pulp can be adjusted using conventional acid-base adjusters. The acid-base adjuster includes at least one selected from ammonia, triethanolamine, and citric acid.

[0020] According to the present invention, the solid content of the slurry obtained after mixing and pulping is 15wt% to 45wt%.

[0021] According to the present invention, the Co salt is a soluble Co salt, comprising at least one of cobalt nitrate, cobalt hypochlorite, and cobalt oxalate. The Mn salt comprises at least one of manganese nitrate and manganese acetate. The carrier exists in sol form.

[0022] According to the present invention, Co salt solution and Fe salt solution can be prepared separately and then mixed together before being mixed with other raw materials of the catalyst.

[0023] According to the present invention, the spray drying is carried out in a spray dryer. The conditions for spray drying are: hot air temperature between 150 and 350°C. The hot air medium for spray drying is a mixture of air and an inert gas. The volume ratio of air to inert gas is 1:15 to 20. Nitrogen is preferably the inert gas.

[0024] According to the present invention, the calcination conditions are: calcination at 450–700°C for 0.3–5 hours, and the calcination atmosphere is a mixture of air and an inert gas. The calcination atmosphere is a mixture of air and inert gas in a volume ratio of 1:3–12. Nitrogen is preferably the inert gas.

[0025] According to the present invention, the mixing and pulping temperature is 50–80°C. The mixing and pulping time is 0.5–5 hours.

[0026] The third aspect of the present invention provides the application of the above-described catalyst or the catalyst prepared by the above-described method in the synthesis of olefins from syngas.

[0027] According to the present invention, the application is an application in the preparation of α-olefins.

[0028] According to the present invention, the synthesis gas is a mixture of CO2, CO and H2; preferably, the volume ratio of CO to H2 is 1:3.5 to 5.5, and the volume ratio of CO to CO2 is preferably 1:0.2 to 0.5.

[0029] According to the present invention, the reaction conditions are as follows: the reaction temperature is 300–370°C; the reaction pressure is 0.5–5.0 MPa; and the catalyst loading (standard volume hourly space velocity) is 5000–1000 h⁻¹. -1 .

[0030] According to the invention, the application can efficiently convert syngas containing a certain proportion of CO2 and rich in H2 into organic hydrocarbons rich in olefins, especially α-olefins, while solving the problem of carbon deposition leading to deactivation of cobalt-based catalysts under high-temperature Fischer-Tropsch conditions.

[0031] Compared with the prior art, the main advantages of this invention are as follows:

[0032] (1) The catalyst of the present invention comprises, by weight, A) 50-80 parts of support; B) 20-50 parts of active component, wherein the active component contains a composition with the following chemical formula on an atomic basis: Co 100 Mn a K 2b Fe b O x This invention utilizes a Co-based catalyst by doping it with a specific ratio of Fe and K elements, and further ensuring that the Fe and K elements on the catalyst surface are distributed within a certain range. This catalyst is particularly suitable for the conversion of syngas containing a certain proportion of CO2 and rich in H2 to produce organic hydrocarbons. When used in this reaction, the catalyst offers the advantages of high-efficiency conversion of syngas while simultaneously producing a high content of α-olefins in the products.

[0033] (2) In the preparation method of the catalyst of the present invention, potassium ferrate is added during the preparation of the Co-Mn catalyst to achieve Fe and K doping. By controlling the preparation process, especially the selection of the calcination atmosphere and the spray forming atmosphere, Fe and K on the catalyst surface are distributed in a certain proportion. This catalyst is particularly suitable for the conversion of syngas containing a certain proportion of CO2 and rich in H2 to produce organic hydrocarbons. The catalyst used in this reaction has the advantages of high efficiency in converting syngas while the product contains a high content of α-olefins.

[0034] (3) In the application of the catalyst of the present invention, the catalyst is suitable for the syngas conversion to olefins reaction, especially for the syngas conversion to olefins reaction with a certain proportion of CO2 and rich in H2. When the catalyst is applied to this reaction, it can convert syngas with high efficiency and the product contains a high content of α-olefins, while solving the problem of cobalt-based catalysts being prone to carbon deposition and deactivation under high temperature Fischer-Tropsch conditions. Detailed Implementation

[0035] In this invention, the elemental analysis of the catalyst surface was performed using an EscalLab Xi+ X-ray photoelectron spectroscopy (XPS) instrument.

[0036] In this invention, C2 + Hydrocarbons are hydrocarbons with 2 to 20 carbon atoms.

[0037] In this invention, the catalyst evaluation methods for Examples 1-4 and Comparative Examples 1-4 are as follows:

[0038] The catalyst is reduced using an in-situ reduction method. After the reduction is complete, the process conditions are switched directly to the synthesis reaction conditions in the reactor used for the reduction to start the reaction.

[0039] Reactor specifications: Millimeter fluidized bed reactor;

[0040] Catalyst loading: 50 grams;

[0041] The reduction conditions are: temperature 400℃

[0042] Pressure 0.1MPa

[0043] Catalyst loading (standard volume hourly space velocity) 6000 h -1

[0044] reducing gas H2

[0045] Restoration time: 12 hours

[0046] The synthesis reaction conditions were: reaction temperature 320℃.

[0047] Reaction pressure 2.5 MPa

[0048] Catalyst loading (standard volume hourly space velocity) 6000 h -1

[0049] The feedstock ratio in the syngas is CO / CO2 / H2 = 1:0.3:4

[0050] The reaction ran for 100 hours.

[0051] Example 1

[0052] Dissolve 1 mol of Co(NO3)2·6H2O in water to prepare a 0.5 mol / L Co elemental solution I. Dissolve 0.5 mol of Mn(NO3)2 in water to prepare a 0.5 mol / L Mn elemental solution II. Mix solutions I and II to obtain solution III. Take a sample containing 477g of Co. 40 wt% zirconium sol of ZrO2 and 0.05 mol / L aqueous solution of K2FeO4 were sequentially added to solution III, and then stirred and slurried at 60°C for 0.5 h. The pH of the mixture was adjusted to 5 with 25 wt% ammonia water, and the solid content of the mixture was adjusted to 35% with water to obtain a slurry. The slurry was spray-dried and shaped, with the sprayer inlet temperature at 350°C and the outlet temperature at 200°C. The hot air medium of the sprayer was a mixture of inert gas and air at a volume ratio of 18:1. The spray-dried material was then calcined at 550°C for 1 h in a low-oxygen atmosphere with a nitrogen to air volume ratio of 10 to obtain a catalyst. The catalyst composition was: 20 wt% Co 100 Mn 50 K 10 Fe5O x +80wt% ZrO2.

[0053] XPS analysis showed that the surface K to Fe molar ratio of the prepared catalyst was 0.7:1.

[0054] The catalyst evaluation results are shown in Table 1.

[0055] Example 2

[0056] Dissolve 1 mol of Co(NO3)2·6H2O in water to prepare a 0.5 mol / L Co elemental solution I. Dissolve 0.3 mol of Mn(NO3)2 in water to prepare a 0.5 mol / L Mn elemental solution II. Mix solutions I and II to obtain solution III. Take 40 wt% zirconium sol containing 120 g of ZrO2 and a 0.5 mol / L aqueous solution of K2FeO4, and add them sequentially to solution III. The mixture was then stirred and pulped at 60℃ for 1 hour. The pH of the mixture was adjusted to 5 with 25wt% ammonia water, and the solid content of the mixture was adjusted to 35% with water to obtain a slurry. The slurry was then spray-dried and shaped. The inlet temperature of the sprayer was 350℃, the outlet temperature was 200℃, and the hot air medium of the sprayer was a mixture of inert gas and air at a volume ratio of 18:1 to obtain a spray-dried material. This material was then calcined at 550℃ for 1 hour in a low-oxygen atmosphere with a nitrogen to air volume ratio of 10 to obtain a catalyst. The catalyst composition was: 50wt% Co. 100 Mn 30 K 14 Fe7O x +50wt% ZrO2.

[0057] XPS analysis showed that the molar ratio of K to Fe on the surface of the prepared catalyst was 0.9:1.

[0058] The catalyst evaluation results are shown in Table 1.

[0059] Example 3

[0060] Dissolve 1 mol of Co(NO3)2·6H2O in water to prepare a 0.5 mol / L Co elemental solution I. Dissolve 0.6 mol of Mn(NO3)2 in water to prepare a 0.5 mol / L Mn elemental solution II. Mix solutions I and II to obtain solution III. Take 40 wt% aluminum sol containing 477 g of Al2O3 and 0.02 mol of K2FeO4 in a 0.5 mol / L aqueous solution, and add them sequentially to solution III. Then, the mixture was stirred and pulped at 60℃ for 2 hours. The pH of the mixture was adjusted to 5 with 25wt% ammonia water, and the solid content of the mixture was adjusted to 35% with water to obtain a slurry. The slurry was then spray-dried and shaped. The inlet temperature of the sprayer was 350℃, the outlet temperature was 200℃, and the hot air medium of the sprayer was a mixture of inert gas and air at a volume ratio of 18:1 to obtain a spray-dried material. This material was then calcined at 550℃ for 1 hour in a low-oxygen atmosphere with a nitrogen to air volume ratio of 10 to obtain a catalyst. The catalyst composition was: 20wt% Co. 100 Mn 60 K4Fe2O x+80wt% Al2O3.

[0061] XPS analysis showed that the molar ratio of K to Fe on the surface of the prepared catalyst was 0.5:1.

[0062] The catalyst evaluation results are shown in Table 1.

[0063] Example 4

[0064] Dissolve 1 mol of Co(NO3)2·6H2O in water to prepare a 0.5 mol / L Co elemental solution I. Dissolve 0.5 mol of Mn(NO3)2 in water to prepare a 0.5 mol / L Mn elemental solution II. Mix solutions I and II to obtain solution III. Take a sample containing 477g of Co. 40 wt% zirconium sol of ZrO2 and 0.05 mol / L aqueous solution of K2FeO4 were sequentially added to solution III, and then stirred and slurried at 60°C for 3 h. The pH of the mixture was adjusted to 5 with 25 wt% triethanolamine, and the solid content of the mixture was adjusted to 35% with water to obtain a slurry. The slurry was spray-dried and shaped, with the sprayer inlet temperature at 350°C and the outlet temperature at 200°C. The hot air medium of the sprayer was a mixture of inert gas and air at a volume ratio of 15:1. The spray-dried material was then calcined at 650°C for 1 h under a low-oxygen atmosphere with a nitrogen to air volume ratio of 10 to obtain a catalyst. The catalyst composition was: 20 wt% Co 100 Mn 50 K 10 Fe5O x +80wt% ZrO2.

[0065] XPS analysis showed that the molar ratio of K to Fe on the surface of the prepared catalyst was 0.6:1.

[0066] The catalyst evaluation results are shown in Table 1.

[0067] Example 5

[0068] The catalyst preparation was the same as in Example 1, except that the ratio of CO / CO2 / H2 in the syngas was evaluated to be 1:0.5:5.

[0069] The catalyst evaluation results are shown in Table 1.

[0070] Comparative Example 1

[0071] Dissolve 1 mol of Co(NO3)2·6H2O in water to prepare a 0.5 mol / L Co elemental solution I. Dissolve 0.5 mol of Mn(NO3)2 in water to prepare a 0.5 mol / L Mn elemental solution II. Mix solutions I and II to obtain solution III. Take a sample containing 477g of Co. 40 wt% zirconium sol, 0.1 mol of KOH in a 0.5 mol / L aqueous solution, and 0.05 mol of Fe(NO3)3·9H2O in a 0.5 mol / L Fe elemental solution were sequentially added to solution III. The mixture was then stirred and slurried at 60 °C for 0.5 h. The pH of the mixture was adjusted to 5 with 25 wt% ammonia water, and the solid content of the mixture was adjusted to 35% with water to obtain a slurry. The slurry was then spray-dried and shaped. The inlet temperature of the sprayer was 350 °C, the outlet temperature was 200 °C, and the hot air medium of the sprayer was a mixture of inert gas and air in a volume ratio of 18:1 to obtain a spray-dried material. The material was then calcined at 550 °C for 1 h in a low-oxygen atmosphere with a nitrogen to air volume ratio of 10 to obtain a catalyst.

[0072] The catalyst has the following composition: 20 wt% Co 100 Mn 50 K 10 Fe5O x +80wt% ZrO2.

[0073] XPS analysis showed that the molar ratio of K to Fe on the surface of the prepared catalyst was 2:1.

[0074] The catalyst evaluation results are shown in Table 1.

[0075] Comparative Example 2

[0076] Dissolve 1 mol of Co(NO3)2·6H2O in water to prepare a 0.5 mol / L Co elemental solution I. Dissolve 0.5 mol of Mn(NO3)2 in water to prepare a 0.5 mol / L Mn elemental solution II. Mix solutions I and II to obtain solution III. Take a sample containing 477g of Co. 40 wt% zirconium sol of ZrO2 and 0.07 mol of 0.5 mol / L aqueous solution of KMnO4 were sequentially added to solution III, and then stirred and slurried at 60 °C for 0.5 h. The pH of the mixture was adjusted to 5 with 25 wt% ammonia water, and the solid content of the mixture was adjusted to 35% with water to obtain a slurry. The slurry was spray-dried and shaped, with the sprayer inlet temperature at 350 °C and the outlet temperature at 200 °C. The hot air medium of the sprayer was a mixture of inert gas and air at a volume ratio of 18:1. The spray-dried material was then calcined at 550 °C for 1 h in a low-oxygen atmosphere with a nitrogen to air volume ratio of 10 to obtain a catalyst. The catalyst composition was: 20 wt% Co 100 Mn 57 K7Ox +80wt% ZrO2.

[0077] The catalyst evaluation results are shown in Table 1.

[0078] Comparative Example 3

[0079] 1 mol of Co(NO3)2·6H2O was dissolved in water to prepare a 0.5 mol / L Co elemental solution I. 0.5 mol of Mn(NO3)2 was dissolved in water to prepare a 0.5 mol / L Mn elemental solution II. Solutions I and II were mixed to obtain solution III. 40 wt% zirconium sol containing 477 g ZrO2 and a 0.5 mol / L aqueous solution of K2FeO4 were added sequentially to solution III. The mixture was then stirred and slurried at 60 °C for 0.5 h. The pH of the mixture was adjusted to 5 with 25 wt% ammonia water. The solid content of the mixture was adjusted to 35% with water to obtain a slurry. The slurry was spray-dried and shaped. The sprayer inlet temperature was 350 °C, the outlet temperature was 200 °C, and the hot air medium was air to obtain the spray-dried material. The material was then calcined at 550 °C for 1 h in a low-oxygen atmosphere with a nitrogen to air volume ratio of 10 to obtain the catalyst. The catalyst has the following composition: 20 wt% Co 100 Mn 50 K 10 Fe5O x +80wt% ZrO2.

[0080] XPS analysis showed that the molar ratio of K to Fe on the surface of the prepared catalyst was 0.2:1.

[0081] The catalyst evaluation results are shown in Table 1.

[0082] Comparative Example 4

[0083] 1 mol of Co(NO3)2·6H2O was dissolved in water to prepare a 0.5 mol / L Co elemental solution I. 0.5 mol of Mn(NO3)2 was dissolved in water to prepare a 0.5 mol / L Mn elemental solution II. Solutions I and II were mixed to obtain solution III. 40 wt% zirconium sol containing 477 g ZrO2 and a 0.5 mol / L aqueous solution of K2FeO4 were added sequentially to solution III. The mixture was then stirred and slurried at 60 °C for 0.5 h. The pH of the mixture was adjusted to 5 with 25 wt% ammonia water. The solid content of the mixture was adjusted to 35% with water to obtain a slurry. The slurry was spray-dried and shaped. The inlet temperature of the sprayer was 350 °C, the outlet temperature was 200 °C, and the hot air medium of the sprayer was a mixture of inert gas and air at a volume ratio of 18:1 to obtain the spray-dried material. The material was then calcined at 550 °C for 1 h in an air atmosphere to obtain the catalyst. The catalyst has the following composition: 20 wt% Co100 Mn 50 K 10 Fe5O x +80wt% ZrO2.

[0084] XPS analysis showed that the molar ratio of K to Fe on the surface of the prepared catalyst was 0.15:1.

[0085] The catalyst evaluation results are shown in Table 1.

[0086] Comparative Example 5

[0087] The catalyst preparation was the same as in Example 5, except that the synthesis gas was evaluated to contain no CO2 and the CO / H2 ratio was 1:5.

[0088] The catalyst evaluation results are shown in Table 1.

[0089] Table 1

[0090]

[0091] The specific embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A catalyst for the preparation of olefins from syngas, wherein, The catalyst, by weight, comprises A) 50–80 copies of the carrier; B) 20-50 parts of active ingredient, the active ingredient containing a composition with the following chemical formula in atomic ratio: What 100 Mn a K 2b Fe b ABOUT x The value of a ranges from 30 to 60; The value of b ranges from 1 to 10; x represents the total number of oxygen atoms required to satisfy the oxidation states of all elements in the catalyst. The molar ratio of K to Fe on the catalyst surface is K:Fe = 0.3~1.3:

1.

2. The catalyst according to claim 1, characterized in that, The support includes at least one of oxides of Al and Zr.

3. The catalyst according to claim 1, characterized in that, The molar ratio of K to Fe on the catalyst surface is K:Fe = 0.5~1.1:

1.

4. A method for preparing the catalyst according to any one of claims 1 to 3, comprising the following steps: The catalyst was obtained by mixing a mixture of Co and Mn salts, a support, and K2FeO4, followed by spray drying and calcination.

5. The preparation method according to claim 4, characterized in that, The solid content of the slurry obtained after mixing and pulping is 15wt%~45wt%.

6. The preparation method according to claim 4, characterized in that, The Co salt is a soluble Co salt, which includes at least one of cobalt nitrate, cobalt hypochlorite, and cobalt oxalate; And / or, the Mn salt includes at least one of manganese nitrate and manganese acetate; And / or, the carrier exists in sol form.

7. The preparation method according to claim 4, characterized in that, The conditions for spray drying are: hot air temperature between 150 and 350°C; and / or, the hot air medium for spray drying is a mixture of air and inert gas, with a volume ratio of air to inert gas of 1:15 to 20.

8. The preparation method according to claim 4, characterized in that, The calcination conditions are: calcination at 450–700°C for 0.3–5 hours; and / or, the calcination atmosphere is a mixture of air and inert gas in a volume ratio of 1:3–12.

9. The use of the catalyst according to any one of claims 1 to 3 or the catalyst prepared by any one of claims 4 to 8 in the synthesis of olefins from syngas.

10. The application according to claim 9, characterized in that, The application is in the preparation of α-olefins.

11. The application according to claim 9, characterized in that, The synthesis gas is a mixture of CO2, CO and H2.

12. The application according to claim 11, characterized in that, The volume ratio of CO to H2 is 1:3.5~5.

5.

13. The application according to claim 11 or 12, characterized in that, The volume ratio of CO to CO2 is 1:0.2~0.5.

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