阅读说明：本技术 合成气制低碳烯烃的方法 (Method for preparing low-carbon olefin from synthesis gas ) 是由 庞颖聪 陶跃武 李剑锋 赵相武 于 2019-09-24 设计创作，主要内容包括：本发明公开了一种合成气制低碳烯烃的方法,包括使合成气与用CH-4还原处理过的催化剂接触,反应生成低碳烯烃。所述催化剂的活性组分包括如下式表示的组合物：Fe-(100)A-aB-bSi-cO-x,其中A选自Mn、Mo、W和V；B选自碱金属元素；a的取值范围为10.0-200.0；b的取值范围为1.0-10.0；c的取值范围为50.0-500.0；x为满足式中各元素化合价所需的氧原子总数。本发明的方法具有反应撤热快,不易飞温以及低碳烯烃重量选择性高的优点。(The invention discloses a method for preparing low-carbon olefin by using synthesis gas, which comprises the steps of mixing the synthesis gas with CH 4 The reduced catalyst is contacted and reacts to generate low-carbon olefin. The active component of the catalyst comprises a composition represented by the formula: fe 100 A a B b Si c O x Wherein A is selected from Mn, Mo, W and V; b is selected from alkali metal elements; a ofThe value range is 10.0-200.0; the value range of b is 1.0-10.0; the value range of c is 50.0-500.0; x is the total number of oxygen atoms required to satisfy the valences of the elements in the formula. The method has the advantages of quick reaction heat removal, difficult temperature runaway and high weight selectivity of the low-carbon olefin.)

1. A process for preparing low-carbon olefin from synthetic gas includes such steps as mixing the synthetic gas with CH₄The reduced catalyst is contacted and reacts to generate low-carbon olefin.

2. The method of claim 1, wherein the catalyst is a catalystThe active ingredient of (a) includes a composition represented by the formula: fe₁₀₀A_aB_bSi_cO_xWherein A is selected from Mn, Mo, W and V; b is selected from alkali metal elements; the value range of a is 10.0-200.0; the value range of b is 1.0-10.0; the value range of c is 50.0-500.0; x is the number of oxygen atoms required to satisfy the valences of the elements in the formula.

3. The process according to claim 1 or 2, characterized in that the specific surface area of the catalyst is between 60 and 120m²/g。

4. The method of any one of claims 1-3, wherein CH is used₄The pressure of the reduction treatment catalyst is 0.1 to 8.0MPa, preferably 0.5 to 5.0 MPa.

5. The method of any one of claims 1-4, wherein CH is used₄The temperature of the reduction treatment catalyst is 400-500 ℃, and preferably 420-480 ℃.

6. The method of any one of claims 1-5, wherein CH is used₄The actual volume space velocity of the reduction treatment catalyst is 300-^-1Preferably 500-1000 hours^-1。

7. The method of any one of claims 1-6, wherein the syngas comprises H₂And CO; preferably said H₂And CO in a molar ratio of 0.5 to 5.0.

8. The method according to any one of claims 1 to 7, wherein the reaction pressure for preparing the low-carbon olefin from the synthesis gas is 0.1 to 8.0MPa, preferably 0.7 to 6.0 MPa; and/or the reaction temperature is 250-430 ℃, preferably 280-380 ℃; and/or the space velocity of the reaction volume is 300-^-1Preferably 500-1000 hours^-1。

9. The method of any one of claims 1-9, wherein the catalyst is prepared by a method comprising:

s1, preparing a hydroxide precipitate I of Fe and a soluble salt solution II of A respectively;

s2, mixing the precipitate I with the solution II to obtain slurry III;

s3, adding the soluble salt solution of the B and the Si sol into the slurry III, mixing and pulping to obtain slurry IV;

s4, adjusting the pH value of the slurry IV to 1-5 to obtain slurry V;

and S5, carrying out spray drying treatment on the slurry V, and then roasting to obtain the catalyst.

10. The process according to claim 9, characterized in that the fresh hydroxide precipitate I of Fe is prepared by: adding a precipitator into the Fe salt solution to precipitate Fe ions in the Fe salt solution to obtain fresh Fe hydroxide precipitate; preferably, the precipitant is an alkaline substance, more preferably aqueous ammonia.

Technical Field

The invention relates to a method for preparing low-carbon olefin from synthesis gas, belonging to the field of olefin preparation.

Background

The low-carbon olefin is generally the olefin with the carbon atom less than or equal to 4, and is an important organic chemical raw material. The low-carbon olefin represented by ethylene/propylene is a base stone and a mark in the petrochemical industry, and has great influence on national economy. With the decreasing petroleum resources and the rapid development of C1 chemistry, the traditional petroleum route for the production of lower olefins is suffering a huge impact under the current impact of middle east ethane and North American shale gas for the production of olefins, which seriously affects the competitiveness and sustainable development of the petrochemical industry. Therefore, the development of low-cost and high-efficiency low-carbon olefin production technology plays an important role in the petroleum safety strategy of oil-deficient countries. The direct production of light olefins from synthesis gas has become one of the popular research directions.

F-T (Fascher-Tropsh) synthesis is a process for synthesizing hydrocarbon by utilizing synthesis gas (the main components are CO and H2) under the action of a catalyst, and is an important way for indirectly liquefying coal and natural gas. The currently common fischer-tropsch synthesis processes are classified into three main groups, depending on the reactor used: a fixed bed F-T synthesis process, a fluidized bed F-T support synthesis process (including a circulating fluidized bed and a fixed fluidized bed) and a slurry bed F-T synthesis process; from the synthesis condition point of view, the classification is divided into two main categories: a high-temperature F-T synthesis process and a low-temperature F-T synthesis process. The fixed bed and slurry bed are generally applied to low temperature F-T process, and are mostly used for producing heavy oil and wax, while the fluidized bed is more suitable for high temperature F-T process for producing lighter hydrocarbons. The commonly used F-T catalysts are divided into two main groups in terms of active components: fe-based catalysts and Co-based catalysts.

In recent years, F-T catalysts reported in documents and patents are more suitable for producing high-carbon long-chain hydrocarbons by using a low-temperature high-pressure slurry bed reactor, and are generally precipitated iron catalysts or impregnated cobalt catalysts. A process for preparing precipitated iron catalysts for F-T synthesis suitable for use in slurry bed reactors is reported, for example, in U.S. Rentech in patents USP5504118 and CN 1113905A. The Fischer-Tropsch synthesis of light hydrocarbon is generally carried out in a fluidized bed reactor, and the process has the characteristics of higher reaction temperature, higher conversion rate and no difficulty of liquid-solid separation. At present, most of the reported catalysts applied to the fluidized bed F-T synthesis are molten iron type catalysts, and some types of precipitated iron catalysts are coupled. For example, patent CN1704161A mentions the preparation of a molten iron type catalyst for F-T synthesis, and patent CN1695804A mentions a precipitated iron catalyst for fluidized bed.

Although there are some attempts to apply a fixed bed to high temperature F-T for producing low carbon olefins, such as German Ruhr, China Union, the F-T synthesis reaction is a strongly exothermic reaction, when a fixed bed is used, the heat removal in the reactor is difficult, the temperature is easy to fly, the catalyst is easy to deactivate, and the attempts are all stopped at a laboratory stage. The fluidized bed can well overcome the problems of the fixed bed, but the catalyst prepared by a molten iron method or the catalyst prepared by a precipitation method for the fluidized bed has the defects of wide product distribution and low yield of low-carbon olefin at present.

Disclosure of Invention

The invention aims to solve the technical problems that in the prior art, because the synthesis reaction of converting synthesis gas into organic matters is a strong exothermic reaction, when a fixed bed is used, the reaction is difficult to remove heat and easy to fly, so that a catalyst is easy to inactivate and the yield of low-carbon olefins is low.

The invention solves the aim of the invention and providesA process for preparing low-carbon olefin from synthetic gas includes mixing said synthetic gas with CH₄The reduced catalyst is contacted and reacts to generate low-carbon olefin.

According to some embodiments of the invention, the active component of the catalyst comprises a composition represented by the formula: fe₁₀₀A_aB_bSi_cO_xWherein A is selected from Mn, Mo, W and V; b is selected from alkali metal elements; the value range of a is 10.0-200.0, preferably 75.0-150.0; the value range of b is 1.0-10.0, preferably 2.5-7.5; the value range of c is 50.0-500.0, preferably 75.0-450.0; x is the total number of oxygen atoms required to satisfy the valences of the elements in the formula.

According to a preferred embodiment of the invention, the specific surface area of the catalyst is between 60 and 120m²/g。

According to some embodiments of the invention, the CH is used₄The pressure of the reduction treatment catalyst is 0.1 to 8.0MPa, preferably 0.5 to 5.0 MPa.

According to a preferred embodiment of the invention, CH is used₄The temperature of the reduction treatment catalyst is 400-500 ℃, and preferably 420-480 ℃.

According to a preferred embodiment of the invention, CH is used₄The actual volume space velocity of the reduction treatment catalyst is 300-^-1Preferably 500-1000 hours^-1。

According to a preferred embodiment of the invention, CH is used₄The time for the reduction treatment of the catalyst is 3 to 10 hours, preferably 5 to 10 hours.

In the prior art, the catalyst needs H first₂Reduction treatment can be used in the reaction of the syngas direct process for producing hydrocarbons, and in order to make the reaction more efficient, one skilled in the art will know that the syngas reduction treatment can be used to treat the H₂Reducing the treated catalyst. The invention adopts a new reduction method, greatly simplifies the reduction process of the catalyst, and adopts a one-step reduction method to achieve the effects of high efficiency and better quality.

According to the invention, the reduction treatment of the catalyst employs CH₄As raw material, reducing and carbonizing a part of Fe element on the surface of the catalyst directly from oxideBeing carbides, CH₄Reduction of treated CH₄The CH can be used in pure form or diluted with other inert gases₄Is used in the form of (1). Those skilled in the art will know which gases are inert to the reaction, such as, but not limited to, N2, inert gases, and the like.

According to some embodiments of the invention, the synthesis gas comprises H₂And CO; preferably said H₂And CO in a molar ratio of 0.5 to 5.0.

According to the preferred embodiment of the invention, the reaction pressure for preparing the low-carbon olefin from the synthesis gas is 0.1-8.0MPa, and preferably 0.5-5.0 MPa.

According to the preferred embodiment of the invention, the reaction temperature for preparing the low-carbon olefin from the synthesis gas is 250-430 ℃, preferably 280-380 ℃.

According to the preferred embodiment of the invention, the actual space velocity of the reaction for preparing the low-carbon olefin from the synthesis gas is 300-1200 h^-1Preferably 500-1000 hours^-1。

According to some embodiments of the invention, the catalyst is prepared by a method comprising:

s1, preparing a hydroxide precipitate I of Fe and a soluble salt solution II of A respectively;

s2, mixing the precipitate I with the solution II to obtain slurry III;

s3, adding the soluble salt solution of the B and the Si sol into the slurry III, mixing and pulping to obtain slurry IV;

s4, adjusting the pH value of the slurry IV to 1-5 to obtain slurry V;

and S5, carrying out spray drying treatment on the slurry V, and then roasting to obtain the catalyst.

According to a preferred embodiment of the invention, the Fe hydroxide precipitate is a fresh Fe hydroxide precipitate. The fresh hydroxide precipitate I of Fe is prepared by the following method: adding a precipitator into the Fe salt solution to precipitate Fe ions in the Fe salt solution to obtain fresh Fe hydroxide precipitate; preferably, the precipitant is an alkaline substance, more preferably aqueous ammonia.

According to a preferred embodiment of the invention, the Fe hydroxide precipitate is not dried, i.e. mixed with the subsequent solution.

The precipitation of fresh hydroxide and subsequent slurrying of other auxiliary agents is entirely a chemical mixing process, and a significant portion of the stale is physical mixing, which is required for the catalyst to achieve the results.

According to a specific embodiment of the present invention, the valence of the iron element in the Fe salt is not particularly limited, and may be +2 and/or + 3.

According to a preferred embodiment of the present invention, in step S4, the pH of slurry IV is adjusted to 1-5 with a pH adjusting agent, preferably ammonia or nitric acid.

According to a preferred embodiment of the invention, the solids content of the slurry V is 15 to 45% by weight, preferably 20 to 40% by weight. As known to those skilled in the art, the solids in slurry V refer to the material remaining after oven drying to constant weight at 100 ℃.

According to a preferred embodiment of the present invention, the spray drying has an inlet temperature such as, but not limited to 380 ℃, 350 ℃, 320 ℃, 270 ℃, 235 ℃, 200 ℃ and the like, and an outlet temperature such as, but not limited to 230 ℃, 200 ℃, 170 ℃, 135 ℃, 105 ℃; the process conditions for the spray-drying treatment can be reasonably determined by one skilled in the art according to requirements.

According to a preferred embodiment of the present invention, the temperature of the calcination is preferably 400 to 750 ℃.

According to a preferred embodiment of the present invention, the time for the calcination is preferably 0.15 to 6 hours. For example, it may be 0.5 hour, 1 hour, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, and any value therebetween.

According to a preferred embodiment of the present invention, the atmosphere for the calcination is preferably an oxygen-containing atmosphere, and air is preferred for economic reasons.

As shown in TEM photo of catalyst, the components of the catalyst of the invention are highly dispersed, and the catalyst has large specific surface area reaching 60-120m²(g), compared with the traditional Fischer-Tropsch catalyst for the fluidized bed, the active site is basically positioned on the surface and does not existIn the direct carbonization-reduction process, the active sites in the interior are blocked and cannot migrate to the surface, so that H is firstly needed₂Reducing and carbonizing with synthetic gas, and directly adopting CH with better carbonizing effect than synthetic gas₄The conversion rate of CO can reach 98 percent by carbonizing and reducing the raw materials, and C₂ ^＝～C₄ ^＝The weight selectivity of the components can be as high as 73.5%.

The finished product rate of the catalyst microspheres with the diameter of 15-170 mu m reaches more than 90%, the particle size distribution presents normal distribution completely suitable for a fluidized bed reactor, and the most probable particle size is 50-60 mu m.

According to a preferred embodiment of the invention, the lower olefin is preferably a C2-C4 hydrocarbon containing C ═ C bonds, often denoted C₂ ^＝～C₄ ^＝。

Drawings

FIG. 1 is a TEM photograph of the catalyst obtained in example 1;

FIG. 2 is a catalyst from example 1 passing through CH₄And (4) a TEM picture after reduction.

Detailed Description

The present invention is further illustrated by the following examples, which are not to be construed as limiting the invention in any way.

[ example 1 ]

1) Preparing a catalyst:

taking 1mol of Fe (NO)₃)₃·9H₂Dissolving O in water to prepare 0.5mol/L Fe solution, carrying out cocurrent flow precipitation on the solution and 1350g of 5 wt% ammonia water, separating, washing with deionized water for three times to obtain fresh Fe (OH)₃Precipitating I; taking 1mol of Mn (NO)₃)₂Dissolving in water to prepare a 30 wt% aqueous solution II; mixing the aqueous solution II with the precipitate I, adding water to prepare a mixture with the solid content of 30 wt%, and stirring in a water bath at 40 ℃ for 24 hours to obtain slurry III; dissolving 0.05mol of RbOH in water to prepare 30 wt% Rb element solution; taking a mixture containing 2mol of SiO₂30 wt% of silica sol; heating the slurry III to 80 ℃ in a water bath at 80 ℃, and then stirring the Rb element solution and the silica sol in the slurrySequentially adding the slurry into the heated slurry III; mixing and pulping at 80 ℃ to obtain a pulp IV; adjusting the pH value of the slurry IV to be 5 by using ammonia water with the concentration of 25 wt% to obtain slurry V (with the solid content of 30%); spray-drying and forming the slurry V, wherein the inlet temperature of a spraying machine is 320 ℃, and the outlet temperature is 190 ℃; then roasting is carried out, the roasting temperature is 600 ℃, the roasting time is 3h, catalyst particles are obtained, and the active components comprise: fe₁₀₀Mn₁₀₀Rb₅Si₂₀₀O_x. The specific surface area of the resulting catalyst was 89m²(ii) in terms of/g. The TEM image of the catalyst is shown in FIG. 1, and the TEM image of the product obtained in the example of the invention is obtained by observing the microscopic morphology of the catalyst by using a transmission electron microscope of model TECAI 20, available from Philips.

2) Evaluation of catalyst:

the catalyst is reduced by adopting an in-situ reduction method, and the process conditions are directly switched to synthesis reaction conditions in a reactor used for reduction after the reduction is finished to start the reaction;

specification of the reactor: a phi 38 mm fluidized bed reactor;

catalyst loading: 50 g;

the reduction conditions are as follows: the temperature is 450 DEG C

Pressure 0.5MPa

Catalyst loading (actual space velocity of reaction) 1000 hours^-1

Reducing gas CH₄

Reduction time 4 hours

The synthesis reaction conditions are as follows: the reaction temperature is 350 DEG C

The reaction pressure is 4.0MPa

Catalyst loading (actual space velocity of reaction) 800 hours^-1

Raw material ratio (mol) H₂/CO＝1/1

The reaction was run for 300 hours.

The results of the synthesis reaction of the prepared catalyst are shown in Table 1.

A TEM photograph of the catalyst after CH4 reduction is shown in fig. 2. As is apparent from the figure, the oxides on the surface of the catalyst are reduced by carbonization to form substances having Fischer-Tropsch activity.

[ example 2 ]

1) Preparing a catalyst:

taking 1mol of Fe (NO)₃)₃·9H₂Dissolving O in water to prepare 0.5mol/L Fe solution, carrying out cocurrent flow precipitation on the solution and 1350g of 5 wt% ammonia water, separating, washing with deionized water for three times to obtain fresh Fe (OH)₃Precipitating I; taking 0.143mol of (NH)₄)₆Mo₇O₂₄·4H₂Dissolving O in water to prepare a 30 wt% aqueous solution II; mixing the aqueous solution II with the precipitate I, adding water to prepare a mixture with the solid content of 30 wt%, and stirring in a water bath at 40 ℃ for 24 hours to obtain slurry III; dissolving 0.05mol of NaOH in water to prepare a 30 wt% Na element solution; taking a mixture containing 3mol of SiO₂30 wt% of silica sol; heating the slurry III to 80 ℃ in a water bath at 80 ℃, and then sequentially adding the Na element solution and the silica sol into the heated slurry III under the condition that the slurry is stirred; mixing and pulping at 80 ℃ to obtain a pulp IV; adjusting the pH value of the slurry to 2 by using nitric acid with the concentration of 25 wt% to obtain slurry V (with the solid content of 30%); spray-drying and forming the slurry V, wherein the inlet temperature of a spraying machine is 300 ℃, and the outlet temperature is 170 ℃; then roasting is carried out, the roasting temperature is 500 ℃, the roasting time is 1h, and catalyst particles are obtained, and the catalyst particles are prepared from the following components: fe₁₀₀Mo₁₀₀Na₅Si₃₀₀O_x。

2) Evaluation of catalyst:

the catalyst is reduced by adopting an in-situ reduction method, and the process conditions are directly switched to synthesis reaction conditions in a reactor used for reduction after the reduction is finished to start the reaction;

specification of the reactor: a phi 38 mm fluidized bed reactor;

catalyst loading: 50 g;

the reduction conditions are as follows: the temperature is 400 DEG C

Pressure 0.1MPa

Catalyst loading (actual space velocity of reaction) 1200 hours^-1

Reducing gas CH₄

Reduction time 3 hours

The synthesis reaction conditions are as follows: the reaction temperature is 340 DEG C

The reaction pressure is 1.0MPa

Catalyst loading (actual space velocity of reaction) 1200 hours^-1

Raw material ratio (mol) H₂/CO＝4/1

The reaction was run for 300 hours.

The results of the synthesis reaction of the prepared catalyst are shown in Table 1.

The specific surface area of the obtained catalyst was 61.2m²/g。

[ example 3 ]

1) Preparing a catalyst:

taking 1mol of Fe (NO)₃)₃·9H₂Dissolving O in water to prepare 0.5mol/L Fe solution, carrying out cocurrent flow precipitation on the solution and 1350g of 5 wt% ammonia water, separating, washing with deionized water for three times to obtain fresh Fe (OH)₃Precipitating I; taking 0.083mol of (NH)₄)₆H₂W₁₂O₄₀Dissolving in water to prepare a 30 wt% aqueous solution II; mixing the aqueous solution II with the precipitate I, adding water to prepare a mixture with the solid content of 30 wt%, and stirring in a water bath at 40 ℃ for 24 hours to obtain slurry III; dissolving 0.05mol of KOH in water to prepare a 30 wt% K element solution; taking a mixture containing 1mol of SiO₂30 wt% of silica sol; heating the slurry III to 80 ℃ in a water bath at 80 ℃, and then sequentially adding the K element solution and the silica sol into the heated slurry III under the condition that the slurry is stirred; mixing and pulping at 80 ℃ to obtain a pulp IV; adjusting the pH value of the slurry to 1 by using nitric acid with the concentration of 25 wt% to obtain slurry V (with the solid content of 30%); spray-drying and forming the slurry V, wherein the inlet temperature of a spraying machine is 310 ℃, and the outlet temperature is 180 ℃; then roasting is carried out, the roasting temperature is 700 ℃, the roasting time is 3h, and catalyst particles are obtained, and the catalyst particles are prepared from the following components: fe₁₀₀W₁₀₀K₅Si₁₀₀O_x。

2) Evaluation of catalyst:

the catalyst is reduced by adopting an in-situ reduction method, and the process conditions are directly switched to synthesis reaction conditions in a reactor used for reduction after the reduction is finished to start the reaction;

specification of the reactor: a phi 38 mm fluidized bed reactor;

catalyst loading: 50 g;

the reduction conditions are as follows: the temperature is 500 DEG C

Pressure 8.0MPa

Catalyst loading (actual space velocity of reaction) 300 hours^-1

Reducing gas CH₄

Reduction time 10 hours

The synthesis reaction conditions are as follows: the reaction temperature is 300 DEG C

The reaction pressure is 2.0MPa

Catalyst loading (actual space velocity of reaction) 300 hours^-1

Raw material ratio (mol) H₂/CO＝5/1

The reaction was run for 300 hours.

The results of the synthesis reaction of the prepared catalyst are shown in Table 1.

The specific surface area of the obtained catalyst was 102m²/g。

[ example 4 ]

1) Preparing a catalyst:

taking 1mol of Fe (NO)₃)₃·9H₂Dissolving O in water to prepare 0.5mol/L Fe solution, carrying out cocurrent flow precipitation on the solution and 1350g of 5 wt% ammonia water, separating, washing with deionized water for three times to obtain fresh Fe (OH)₃Precipitating I; taking 1mol of NH₄VO₃Dissolving in boiling water to prepare a 30 wt% aqueous solution II; mixing the aqueous solution II with the precipitate I, adding water to prepare a mixture with the solid content of 30 wt%, and stirring in a water bath at 40 ℃ for 24 hours to obtain slurry III; dissolving 0.1mol of LiOH in water to prepare a 30 wt% Li element solution; taking a mixture containing 2mol of SiO₂30 wt% of silica sol; heating the slurry III to 80 ℃ in a water bath at 80 ℃, and then sequentially adding the Li element solution and the silica sol into the heated slurry III under the condition that the slurry is stirred; in thatMixing and pulping at 80 ℃ to obtain a pulp IV; adjusting the pH value of the slurry to 3 by using nitric acid with the concentration of 25 wt% to obtain slurry V (with the solid content of 30%); spray-drying and forming the slurry V, wherein the inlet temperature of a spraying machine is 320 ℃, and the outlet temperature is 190 ℃; then roasting is carried out, the roasting temperature is 600 ℃, the roasting time is 3h, and catalyst particles are obtained, and the catalyst particles are prepared from the following components: fe₁₀₀V₁₀₀Li₁₀Si₂₀₀O_x。

2) Evaluation of catalyst:

the catalyst is reduced by adopting an in-situ reduction method, and the process conditions are directly switched to synthesis reaction conditions in a reactor used for reduction after the reduction is finished to start the reaction;

specification of the reactor: a phi 38 mm fluidized bed reactor;

catalyst loading: 50 g;

the reduction conditions are as follows: the temperature is 450 DEG C

Pressure 0.5MPa

Catalyst loading (actual space velocity of reaction) 1000 hours^-1

Reducing gas CH₄

Reduction time 5 hours

The synthesis reaction conditions are as follows: the reaction temperature is 350 DEG C

The reaction pressure is 4.0MPa

Catalyst loading (actual space velocity of reaction) 800 hours^-1

Raw material ratio (mol) H₂/CO＝1/1

The reaction was run for 300 hours.

The results of the synthesis reaction of the prepared catalyst are shown in Table 1.

The specific surface area of the resulting catalyst was 118.6m²/g。

[ example 5 ]

1) Preparing a catalyst:

taking 1mol of Fe (NO)₃)₃·9H₂Dissolving O in water to prepare 0.5mol/L Fe solution, carrying out cocurrent flow precipitation on the solution and 1350g of 5 wt% ammonia water, separating, washing with deionized water for three times to obtain fresh Fe solutionFe(OH)₃Precipitating I; taking 0.1mol of Mn (NO)₃)₂Dissolving in water to prepare a 30 wt% aqueous solution II; mixing the aqueous solution II with the precipitate I, adding water to prepare a mixture with the solid content of 30 wt%, and stirring in a water bath at 40 ℃ for 24 hours to obtain slurry III; dissolving 0.01mol of RbOH in water to prepare 30 wt% Rb element solution; taking a mixture containing 0.5mol of SiO₂30 wt% of silica sol; heating the slurry III to 80 ℃ in a water bath at 80 ℃, and then sequentially adding the Rb element solution and the silica sol into the heated slurry III in a state that the slurry is stirred; mixing and pulping at 80 ℃ to obtain a pulp IV; adjusting the pH value of the slurry to 1 by using nitric acid with the concentration of 25 wt% to obtain slurry V (with the solid content of 30%); spray-drying and forming the slurry V, wherein the inlet temperature of a spraying machine is 280 ℃, and the outlet temperature is 150 ℃; then roasting is carried out, the roasting temperature is 650 ℃, the roasting time is 0.5h, and catalyst particles are obtained, and the catalyst particles comprise the following components: fe₁₀₀Mn₁₀Rb₁Si₅₀O_x。

2) Evaluation of catalyst:

the catalyst is reduced by adopting an in-situ reduction method, and the process conditions are directly switched to synthesis reaction conditions in a reactor used for reduction after the reduction is finished to start the reaction;

specification of the reactor: a phi 38 mm fluidized bed reactor;

catalyst loading: 50 g;

the reduction conditions are as follows: the temperature is 450 DEG C

Pressure 0.5MPa

Catalyst loading (actual space velocity of reaction) 1000 hours^-1

Reducing gas CH₄

Reduction time 4 hours

The synthesis reaction conditions are as follows: the reaction temperature is 350 DEG C

The reaction pressure is 4.0MPa

Catalyst loading (actual space velocity of reaction) 800 hours^-1

Raw material ratio (mol) H₂/CO＝1/1

The reaction was run for 300 hours.

The results of the synthesis reaction of the prepared catalyst are shown in Table 1.

The specific surface area of the obtained catalyst was 70.3m²/g。

[ example 6 ]

1) Preparing a catalyst:

taking 1mol of Fe (NO)₃)₃·9H₂Dissolving O in water to prepare 0.5mol/L Fe solution, carrying out cocurrent flow precipitation on the solution and 1350g of 5 wt% ammonia water, separating, washing with deionized water for three times to obtain fresh Fe (OH)₃Precipitating I; taking 2mol of Mn (NO)₃)₂Dissolving in water to prepare a 30 wt% aqueous solution II; mixing the aqueous solution II with the precipitate I, adding water to prepare a mixture with the solid content of 30 wt%, and stirring in a water bath at 40 ℃ for 24 hours to obtain slurry III; dissolving 0.1mol of RbOH in water to prepare 30 wt% Rb element solution; taking a mixture containing 5mol of SiO₂30 wt% of silica sol; heating the slurry III to 80 ℃ in a water bath at 80 ℃, and then sequentially adding the Rb element solution and the silica sol into the heated slurry III in a state that the slurry is stirred; mixing and pulping at 80 ℃ to obtain a pulp IV; adjusting the pH value of the slurry to 5 by using ammonia water with the concentration of 25 wt% to obtain slurry V (with the solid content of 30%); spray-drying and forming the slurry V, wherein the inlet temperature of a spraying machine is 300 ℃, and the outlet temperature is 165 ℃; then roasting is carried out, the roasting temperature is 600 ℃, the roasting time is 2 hours, and catalyst particles are obtained, and the catalyst particles are prepared from the following components: fe₁₀₀Mn₂₀₀Rb₁₀Si₅₀₀O_x。

2) Evaluation of catalyst:

the catalyst is reduced by adopting an in-situ reduction method, and the process conditions are directly switched to synthesis reaction conditions in a reactor used for reduction after the reduction is finished to start the reaction;

specification of the reactor: a phi 38 mm fluidized bed reactor;

catalyst loading: 50 g;

the reduction conditions are as follows: the temperature is 450 DEG C

Pressure 0.5MPa

Catalyst loading (actual space velocity of reaction) 1000 hours^-1

Reducing gas CH₄

Reduction time 4 hours

The synthesis reaction conditions are as follows: the reaction temperature is 350 DEG C

The reaction pressure is 4.0MPa

Catalyst loading (actual space velocity of reaction) 800 hours^-1

Raw material ratio (mol) H₂/CO＝1/1

The reaction was run for 300 hours.

The results of the synthesis reaction of the prepared catalyst are shown in Table 1.

The specific surface area of the resulting catalyst was 87.6m²/g。

[ COMPARATIVE EXAMPLE 1 ]

1) Preparing a catalyst:

taking 1mol of Fe (NO)₃)₃·9H₂Dissolving O in water to prepare 0.5mol/L Fe solution, carrying out cocurrent flow precipitation on the solution and 1350g of 5 wt% ammonia water, separating, washing with deionized water for three times to obtain fresh Fe (OH)₃Precipitating I; taking 1mol of Mn (NO)₃)₂Dissolving in water to prepare a 30 wt% aqueous solution II; mixing the aqueous solution II with the precipitate I, adding water to prepare a mixture with the solid content of 30 wt%, and stirring in a water bath at 40 ℃ for 24 hours to obtain slurry III; dissolving 0.05mol of RbOH in water to prepare 30 wt% Rb element solution; taking a mixture containing 2mol of SiO₂30 wt% of silica sol; heating the slurry III to 80 ℃ in a water bath at 80 ℃, and then sequentially adding the Rb element solution and the silica sol into the heated slurry III in a state that the slurry is stirred; mixing and pulping at 80 ℃ to obtain a pulp IV; adjusting the pH value of the slurry to 5 by using ammonia water with the concentration of 25 wt% to obtain slurry V (with the solid content of 30%); spray-drying and forming the slurry V, wherein the inlet temperature of a spraying machine is 320 ℃, and the outlet temperature is 190 ℃; then roasting is carried out, the roasting temperature is 600 ℃, the roasting time is 3h, and catalyst particles are obtained, and the catalyst particles are prepared from the following components: fe₁₀₀Mn₁₀₀Rb₅Si₂₀₀O_x。

2) Evaluation of catalyst:

the catalyst is reduced by adopting an in-situ reduction method, and the process conditions are directly switched to synthesis reaction conditions in a reactor used for reduction after the reduction is finished to start the reaction;

specification of the reactor: a phi 38 mm fluidized bed reactor;

catalyst loading: 50 g;

the reduction conditions are as follows: the temperature is 450 DEG C

Pressure 0.5MPa

Catalyst loading (actual space velocity of reaction) 1000 hours^-1

Reducing gas 1H₂

The reduction time is 112 hours

Reducing gas 2H₂/CO＝0.5/1

The reduction time is 224 hours

The synthesis reaction conditions are as follows: the reaction temperature is 350 DEG C

The reaction pressure is 4.0MPa

Catalyst loading (actual space velocity of reaction) 800 hours^-1

Raw material ratio (mol) H₂/CO＝1/1

The reaction was run for 300 hours.

The results of the synthesis reaction of the prepared catalyst are shown in Table 1.

The specific surface area of the obtained catalyst was 131m²/g。

[ COMPARATIVE EXAMPLE 2 ]

1) Preparing a catalyst:

taking 1mol of Fe (NO)₃)₃·9H₂Dissolving O in water to prepare 0.5mol/L Fe solution, carrying out cocurrent flow precipitation on the solution and 1350g of 5 wt% ammonia water, separating, washing with deionized water for three times to obtain fresh Fe (OH)₃Precipitating I; taking 1mol of Mn (NO)₃)₂Dissolving in water to prepare a 30 wt% aqueous solution II; mixing the aqueous solution II with the precipitate I, adding water to prepare a mixture with the solid content of 30 wt%, and stirring in a water bath at 40 ℃ for 24 hours to obtain slurry III; dissolving 0.05mol of RbOH in water to prepare 30 wt% Rb element solution; taking a mixture containing 2mol of SiO₂30 wt% of siliconSol; heating the slurry III to 80 ℃ in a water bath at 80 ℃, and then sequentially adding the Rb element solution and the silica sol into the heated slurry III in a state that the slurry is stirred; mixing and pulping at 80 ℃ to obtain a pulp IV; adjusting the pH value of the slurry to 5 by using ammonia water with the concentration of 25 wt% to obtain slurry V (with the solid content of 30%); spray-drying and forming the slurry V, wherein the inlet temperature of a spraying machine is 320 ℃, and the outlet temperature is 190 ℃; then roasting is carried out, the roasting temperature is 600 ℃, the roasting time is 3h, and catalyst particles are obtained, and the catalyst particles are prepared from the following components: fe₁₀₀Mn₁₀₀Rb₅Si₂₀₀O_x。

2) Evaluation of catalyst:

the catalyst is reduced by adopting an in-situ reduction method, and the process conditions are directly switched to synthesis reaction conditions in a reactor used for reduction after the reduction is finished to start the reaction;

specification of the reactor: a phi 38 mm fluidized bed reactor;

catalyst loading: 50 g;

the reduction conditions are as follows: the temperature is 450 DEG C

Pressure 0.5MPa

Catalyst loading (actual space velocity of reaction) 1000 hours^-1

Reducing gas H₂

The reduction time is 12 hours

The synthesis reaction conditions are as follows: the reaction temperature is 350 DEG C

The reaction pressure is 4.0MPa

Catalyst loading (actual space velocity of reaction) 800 hours^-1

Raw material ratio (mol) H₂/CO＝1/1

The reaction was run for 500 hours.

The results of the synthesis reaction of the prepared catalyst are shown in Table 1.

The specific surface area of the resulting catalyst was 55.8m²/g。

TABLE 1

In Table 1, C₂ ⁰～C₄ ⁰Denotes C2-C4 alkane, C₂ ^＝～C₄ ^＝Represents C2-C4 olefins.

Any numerical value mentioned in this specification, if there is only a two unit interval between any lowest value and any highest value, includes all values from the lowest value to the highest value incremented by one unit at a time. For example, if it is stated that the amount of a component, or a value of a process variable such as temperature, pressure, time, etc., is 50 to 90, it is meant in this specification that values of 51 to 89, 52 to 88 … …, and 69 to 71, and 70 to 71, etc., are specifically enumerated. For non-integer values, units of 0.1, 0.01, 0.001, or 0.0001 may be considered as appropriate. These are only some specifically named examples. In a similar manner, all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be disclosed in this application.

It should be noted that the above-mentioned embodiments are only for explaining the present invention, and do not constitute any limitation to the present invention. The present invention has been described with reference to exemplary embodiments, but the words which have been used herein are words of description and illustration, rather than words of limitation. The invention can be modified, as prescribed, within the scope of the claims and without departing from the scope and spirit of the invention. Although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein, but rather extends to all other methods and applications having the same functionality.