阅读说明：本技术 一种生产低碳烯烃的催化剂及其制备方法和应用 (Catalyst for producing low-carbon olefin and preparation method and application thereof ) 是由 李剑锋 陶跃武 庞颖聪 于 2019-10-09 设计创作，主要内容包括：本发明公开了一种费托合成直接生产低碳烯烃的催化剂及其制备方法和应用。该催化剂中,活性组分含有,以原子比计,化学式如下的化合物：Fe-(100)Mn-aA-bB-cOx,其中A选自Zn、Ga、Ge和In中的一种或多种；B选自Li、Na、K和Cs中的一种或多种。该催化剂是采用氨基甲酸铵和/或甲酸铵溶液作为沉淀剂,并采用制浆混合喷雾一体成型制得的。本发明催化剂用于费托合成直接生产低碳烯烃时,具有原料转化率高,低碳烯烃选择性高的优点,利于大规模流化床工业化生产。(The invention discloses a catalyst for directly producing low-carbon olefin by Fischer-Tropsch synthesis and a preparation method and application thereof. In the catalyst, an active component contains a compound with the following chemical formula in terms of atomic ratio: fe 100 Mn a A b B c Ox, wherein A is selected from one or more of Zn, Ga, Ge and In; b is selected from one or more of Li, Na, K and Cs. The catalyst adopts ammonium carbamate and/or ammonium formate solution as a precipitator and adoptsIs prepared by pulping, mixing and spraying and integrally forming. When the catalyst is used for directly producing the low-carbon olefin by Fischer-Tropsch synthesis, the catalyst has the advantages of high conversion rate of raw materials and high selectivity of the low-carbon olefin, and is beneficial to large-scale fluidized bed industrial production.)

1. The catalyst for directly producing low-carbon olefin by Fischer-Tropsch synthesis comprises the following active components in atomic ratio: fe₁₀₀Mn_aA_bB_cOx, wherein A is selected from one or more of Zn, Ga, Ge and In; b is selected from one or more of Li, Na, K and Cs; the value range of a is 0.5-80.0; the value range of b is 0.1-30.0; the value range of c is 0.1-20.0; x is the total number of oxygen atoms required to satisfy the valence of each element in the catalyst; the catalyst comprises the following characteristic peaks of X-ray diffraction:

2. the catalyst of claim 1, wherein: the catalyst also comprises the following characteristic peaks of X-ray diffraction:

3. the catalyst according to claim 1 or 2, characterized in that: fe₁₀₀Mn_aA_bB_cIn Ox, a has a value range of 8.0-65.0.

4. The catalyst of claim 1, wherein: fe₁₀₀Mn_aA_bB_cIn Ox, the value range of b is 0.5-28.0.

5. The catalyst of claim 1, wherein: in the technical proposal, the device comprises a base,Fe₁₀₀Mn_aA_bB_cin Ox, the value range of c is 0.5-18.0.

6. A preparation method of a catalyst for directly producing low-carbon olefin by Fischer-Tropsch synthesis comprises the following steps:

(1) preparing a mixed solution I containing Fe, Mn, A and B elements;

(2) performing cocurrent flow precipitation on the solution I and the ammonium carbamate or ammonium formate solution II to obtain mixed slurry III;

(3) and feeding the mixed slurry III into a spray dryer for spray forming, and then roasting to obtain the catalyst.

7. The method of claim 6, wherein: and (3) the molar ratio of the ammonium carbamate and/or the ammonium formate to the total metal ions in the solution I in the step (2) is 1.0-4.0.

8. The method of claim 6, wherein: in the step (2), after the precipitation is finished, aging is preferably performed under the following conditions: the temperature is 10-30 ℃, and the time is 1-72 hours.

9. The method of claim 6, wherein: the roasting conditions in the step (3) are as follows: the roasting temperature is 400-1000 ℃, the roasting time is 1-12 hours, and the preferable roasting conditions are as follows: the roasting temperature is 500-800 ℃, and the roasting time is 4-10 hours.

10. Use of a catalyst according to any one of claims 1 to 5 or a catalyst prepared by a method according to any one of claims 6 to 9 in the direct production of lower olefins by fischer-tropsch synthesis.

Technical Field

The invention relates to a catalyst used in Fischer-Tropsch synthesis reaction, in particular to a catalyst for directly producing low-carbon olefin by Fischer-Tropsch synthesis, a preparation method and application thereof.

Background

The process for directly producing the low-carbon olefin from the synthesis gas is a process for directly obtaining the low-carbon olefin with the carbon atom number less than or equal to 4 through the Fischer-Tropsch synthesis reaction under the action of the catalyst, and the process does not need to further prepare the olefin from the synthesis gas through methanol or dimethyl ether like an indirect process, thereby simplifying the process flow and greatly reducing the investment. Meanwhile, coal resources can be utilized to prepare synthesis gas through gas making, and the abundant coal resources and the relatively low coal price in China provide good market opportunity for developing a process for directly producing low-carbon olefin from coal-based synthesis gas.

The technology of directly producing low-carbon olefin by using synthesis gas becomes a hot point for developing Fischer-Tropsch synthesis reaction. CN03109585.2 discloses a catalyst for directly producing low-carbon olefins from synthesis gas, which is a Fe/activated carbon catalyst using manganese, copper, zinc, silicon, potassium and the like as auxiliary agents and prepared by a vacuum impregnation method, when the catalyst is used for preparing low-carbon olefins from synthesis gas, the CO conversion rate is 96% and the selectivity of the low-carbon olefins in hydrocarbons is 68% under the condition of no circulation of raw material gas. However, the preparation process of the catalyst is complex, the cost is high, and the catalyst can only be applied in a fixed bed, which is not beneficial to large-scale fluidized bed industrial production.

Disclosure of Invention

One of the technical problems to be solved by the invention is the problem of low selectivity of low-carbon olefin in the reaction for directly producing low-carbon olefin in the prior art, and provides a novel catalyst for directly producing low-carbon olefin, and a preparation method and application thereof. The catalyst has the advantages of high conversion rate of raw materials and high selectivity of low-carbon olefin, and is beneficial to large-scale fluidized bed industrial production.

The invention provides a catalyst for directly producing low-carbon olefin by Fischer-Tropsch synthesis, which comprises the following active components in atomic ratio: fe₁₀₀Mn_aA_bB_cOx, wherein A is selected from one or more of Zn, Ga, Ge and In; b is selected from one or more of Li, Na, K and Cs; the value range of a is 0.5-80.0; the value range of b is 0.1-30.0; the value range of c is 0.1-20.0; x is the total number of oxygen atoms required to satisfy the valence of each element in the catalyst; the catalyst comprises the following characteristic peaks of X-ray diffraction:

in the above technical solution, the catalyst further comprises the following characteristic peaks of X-ray diffraction:

in the above technical scheme, Fe₁₀₀Mn_aA_bB_cIn Ox, the value range of a is preferably 8.0-65.0.

In the above technical scheme, Fe₁₀₀Mn_aA_bB_cIn Ox, the value range of b is preferably 0.5-28.0.

In the above technical scheme, Fe₁₀₀Mn_aA_bB_cIn Ox, the preferable value range of c is 0.5-18.0.

The second aspect of the invention provides a preparation method of a catalyst for directly producing low-carbon olefins by Fischer-Tropsch synthesis, which comprises the following steps:

(1) preparing a mixed solution I containing Fe, Mn, A and B elements;

(2) performing cocurrent precipitation on the solution I and the ammonium carbamate and/or ammonium formate solution II to obtain a mixed slurry III;

(3) and feeding the mixed slurry III into a spray dryer for spray forming, and then roasting to obtain the catalyst.

In the above technical scheme, the mixed solution i containing Fe, Mn, a and B elements prepared in step (1) can be prepared by a conventional method in the art, for example, soluble salts of each element are used for preparation, and soluble Fe salt, Mn salt, a salt and B salt are not particularly limited, and can be selected by a person skilled in the art according to actual needs.

In the technical scheme, the molar ratio of the ammonium carbamate and/or the ammonium formate in the step (2) to the total metal ions in the solution I is 1.0-4.0.

In the above technical scheme, in the step (2), after the precipitation is finished, aging is preferably performed under the following conditions: the temperature is 10-30 ℃, and the time is 1-72 hours.

In the above technical scheme, the roasting conditions in step (3) are as follows: the roasting temperature is 400-1000 ℃, the roasting time is 1-12 hours, and the preferable roasting conditions are as follows: the roasting temperature is 500-800 ℃, and the roasting time is 4-10 hours.

In the technical scheme, the spray forming in the step (4) can be carried out, wherein the particle size can be 50-150 microns, and the shape can be a microspherical shape.

The third aspect of the invention provides an application of the catalyst or the catalyst prepared by the method in the direct production of low-carbon olefin by Fischer-Tropsch synthesis.

In the technical scheme, a fluidized bed reactor is adopted.

In the technical scheme, the application takes the synthesis gas as a raw material, and the raw material is in contact reaction with the catalyst to generate the C-containing catalyst₂～C₄The olefin of (1).

In the above technical scheme, H in the synthesis gas₂The molar ratio of CO to CO is preferably 1 to 3.

In the technical scheme, the reaction temperature is preferably 250-400 ℃.

In the technical scheme, the reaction pressure is preferably 1.0-3.0 MPa.

In the technical scheme, the volume space velocity of the raw material gas is preferably 500-12000 h^-1。

As known to those skilled in the art, the catalyst of the present invention is used for preparing C by Fischer-Tropsch synthesis₂-C₄Before the reaction of the olefin(s) in (b), it is preferable to carry out an on-line reduction treatment step, and the specific reduction conditions can be reasonably selected by those skilled in the art without any inventive step, such as but not limited to the following:

the reduction temperature is 350-650 ℃;

the reducing agent is H₂And/or CO;

the pressure of reduction is normal pressure to 2MPa (measured by gauge pressure);

the volume space velocity of the reducing agent is 1500-6000 hr^-1；

The reduction time is 6-72 hours.

Compared with the prior art, the invention has the following beneficial effects:

the catalyst of the invention adopts ammonium carbamate and/or ammonium formate solution as a precipitator, and can enable metal active ions such as Fe, Mn and the like to be in NH₄ ⁺And HCOO^-The obtained slurry can form a special crystalline phase composition through spray drying and roasting forming, has a specific X-ray diffraction characteristic peak, and is beneficial to improving the catalytic performance of the catalyst.

When the catalyst is used for directly producing the low-carbon olefin by Fischer-Tropsch synthesis, the conversion rate of the raw materials is high, the selectivity of the low-carbon olefin in hydrocarbon can reach 72.2 percent, a better technical effect is achieved, and the catalyst can be used in the fluidized bed industrial production for directly producing the low-carbon olefin by using synthesis gas.

Drawings

FIG. 1 is an XRD pattern of the catalysts of example 1 and comparative example 1;

wherein the upper solid line is an XRD spectrum of the catalyst prepared by the method of example 1 (ammonium carbamate solution precipitant) of the present invention, and the lower solid line is an XRD spectrum of the catalyst prepared by the method of comparative example 1 (ammonia water precipitant).

Detailed Description

The present invention is further illustrated by the following examples, but it should be understood that the scope of the present invention is not limited by the examples.

In the invention, XRD detection data is carried out on a Bruker ADVANCED 8X-ray diffractometer, CuKa radiation is 40 kilovolts and 40 milliamps, the scanning range is 2 theta which is 10-70 degrees, and the scanning speed is 5 DEG/min.

In the present invention, in the XRD data of the catalyst, W, M, S, VS represents the diffraction peak intensity, W is weak, M is medium, S is strong, and VS is very strong, which is well known to those skilled in the art. Generally, W is less than 20, M is 20-40, S is 40-70, and VS is greater than 70.

Example 1

1. Preparation of the catalyst

Iron nitrate nonahydrate (molecular formula: Fe (NO): containing 1 mol of Fe₃)₃·9H₂O), a 50% manganese nitrate solution containing 0.45 mol of Mn (molecular formula: mn (NO)₃)₂) Gallium nitrate pentahydrate containing 0.2 mol of Ga (molecular formula: ga (NO)₃)₃·5H₂O), potassium nitrate containing 0.05 mol K (formula: KNO₃) And dissolving the mixture in deionized water in sequence to obtain a metal ion mixed solution I after complete dissolution. And 2.2 mol of ammonium carbamate is dissolved in deionized water, and after complete dissolution, a precipitant solution II is obtained. And (3) carrying out cocurrent feeding on the metal ion mixed solution I and the precipitator solution II, carrying out coprecipitation reaction, and aging at 20 ℃ for 36 hours to obtain mixed slurry III. And (3) feeding the mixed slurry III into a spray dryer, spray-drying to obtain microspherical fine particles, and roasting at the roasting temperature of 650 ℃ for 8 hours to obtain the catalyst.

The prepared catalyst comprises the following components: fe₁₀₀Mn₄₅Ga₂₀K₅O_X。

The XRD pattern of the catalyst of this example is shown in FIG. 1.

2. The catalyst prepared in the step 1 is subjected to reduction treatment, and the reaction conditions are as follows:

3. catalyst evaluation

Millimeter fluidized bed reactor

For convenience of comparison, the composition of the catalyst of the present invention and the evaluation results are shown in Table 1.

Example 2

1. Preparation of the catalyst

Iron nitrate nonahydrate (molecular formula: Fe (NO): containing 1 mol of Fe₃)₃·9H₂O), a 50% manganese nitrate solution containing 0.30 mol of Mn (molecular formula: mn (NO)₃)₂) Gallium nitrate pentahydrate containing 0.10 mol of Ga (molecular formula: ga (NO)₃)₃·5H₂O), potassium nitrate containing 0.10 mol K (formula: KNO₃) And dissolving the mixture in deionized water in sequence to obtain a metal ion mixed solution I after complete dissolution. 2.2 mol of ammonium formate is dissolved in deionized water, and after complete dissolution, a precipitant solution II is obtained. And (3) carrying out cocurrent feeding on the metal ion mixed solution I and the precipitator solution II, carrying out coprecipitation reaction, and aging at 20 ℃ for 36 hours to obtain mixed slurry III. And (3) feeding the mixed slurry III into a spray dryer, spray-drying to obtain microspherical fine particles, and roasting at the roasting temperature of 650 ℃ for 8 hours to obtain the catalyst.

Composition of the catalyst obtainedComprises the following steps: fe₁₀₀Mn₃₀Ga₁₀K₁₀O_X。

The X-ray diffraction peaks of the catalyst of this example were similar to those of the catalyst of example 1.

2. The catalyst obtained in step 1 was subjected to reduction treatment under the same conditions as in example 1.

3. Catalyst evaluation and reaction conditions were as in example 1.

For convenience of comparison, the composition of the catalyst of this example and the evaluation results are shown in Table 1.

Example 3

1. Preparation of the catalyst

Iron nitrate nonahydrate (molecular formula: Fe (NO): containing 1 mol of Fe₃)₃·9H₂O), a 50% manganese nitrate solution containing 0.60 mol of Mn (molecular formula: mn (NO)₃)₂) Zinc nitrate hexahydrate containing 0.01 mole of Zn (formula: zn (NO)₃)₂·6H₂O), lithium nitrate containing 0.15 mol of Li (formula: LiNO₃) And dissolving the mixture in deionized water in sequence to obtain a metal ion mixed solution I after complete dissolution. 3.52 mol of ammonium carbamate is dissolved in deionized water, and after complete dissolution, precipitant solution II is obtained. And (3) carrying out cocurrent feeding on the metal ion mixed solution I and the precipitator solution II, carrying out coprecipitation reaction, and aging at 30 ℃ for 1 hour to obtain mixed slurry III. And (3) feeding the mixed slurry III into a spray dryer, spray-drying to obtain microspherical fine particles, and roasting at the roasting temperature of 500 ℃ for 10 hours to obtain the catalyst.

The prepared catalyst comprises the following components: fe₁₀₀Mn₆₀Zn₁Li₁₅O_X。

The X-ray diffraction peaks of the catalyst of this example were similar to those of the catalyst of example 1.

2. The catalyst obtained in step 1 was subjected to reduction treatment under the same conditions as in example 1.

3. Catalyst evaluation and reaction conditions were as in example 1.

For convenience of comparison, the composition of the catalyst of this example and the evaluation results are shown in Table 1.

Example 4

1. Preparation of the catalyst

Iron nitrate nonahydrate (molecular formula: Fe (NO): containing 1 mol of Fe₃)₃·9H₂O), a 50% manganese nitrate solution containing 0.10 mol of Mn (molecular formula: mn (NO)₃)₂) Germanium nitrate containing 0.25 mol Ge (formula: ge (NO)₃)₄) Sodium nitrate containing 0.01 mol of Na (formula: NaNO₃) And dissolving the mixture in deionized water in sequence to obtain a metal ion mixed solution I after complete dissolution. 1.36 mol of ammonium carbamate is dissolved in deionized water, and after complete dissolution, a precipitant solution II is obtained. And (3) carrying out cocurrent feeding on the metal ion mixed solution I and the precipitator solution II, carrying out coprecipitation reaction, and aging at 10 ℃ for 72 hours to obtain mixed slurry III. And (3) feeding the mixed slurry III into a spray dryer, spray-drying to obtain microspherical fine particles, and roasting at 800 ℃ for 4 hours to obtain the catalyst.

The prepared catalyst comprises the following components: fe₁₀₀Mn₁₀Ge₂₅Na₁O_X。

The X-ray diffraction peaks of the catalyst of this example were similar to those of the catalyst of example 1.

2. The catalyst obtained in step 1 was subjected to reduction treatment under the same conditions as in example 1.

3. Catalyst evaluation and reaction conditions were as in example 1.

For convenience of comparison, the composition of the catalyst of this example and the evaluation results are shown in Table 1.

Example 5

1. Preparation of the catalyst

Iron nitrate nonahydrate (molecular formula: Fe (NO): containing 1 mol of Fe₃)₃·9H₂O), a 50% manganese nitrate solution containing 0.45 mol of Mn (molecular formula: mn (NO)₃)₂) Indium nitrate pentahydrate containing 0.1 mol of In (molecular formula: in (NO)₃)₃) Cesium nitrate containing 0.05 mol of Cs (formula: CsNO₃) Sequentially dissolve inAnd (4) completely dissolving in deionized water to obtain a metal ion mixed solution I. And 2.2 mol of ammonium carbamate is dissolved in deionized water, and after complete dissolution, a precipitant solution II is obtained. And (3) carrying out cocurrent feeding on the metal ion mixed solution I and the precipitator solution II, carrying out coprecipitation reaction, and aging at 20 ℃ for 36 hours to obtain mixed slurry III. And (3) feeding the mixed slurry III into a spray dryer, spray-drying to obtain microspherical fine particles, and roasting at the roasting temperature of 650 ℃ for 8 hours to obtain the catalyst.

The prepared catalyst comprises the following components: fe₁₀₀Mn₄₅In₁₀Cs₅O_X。

The X-ray diffraction peaks of the catalyst of this example were similar to those of the catalyst of example 1.

2. The catalyst obtained in step 1 was subjected to reduction treatment under the same conditions as in example 1.

3. Catalyst evaluation and reaction conditions were as in example 1.

For convenience of comparison, the composition of the catalyst of this example and the evaluation results are shown in Table 1.

Example 6

1. Preparation of the catalyst

Iron nitrate nonahydrate (molecular formula: Fe (NO): containing 1 mol of Fe₃)₃·9H₂O), a 50% manganese nitrate solution containing 0.45 mol of Mn (molecular formula: mn (NO)₃)₂) Zinc nitrate hexahydrate containing 0.1 mole of Zn (molecular formula: zn (NO)₃)₂·6H₂O), cesium nitrate containing 0.05 mol of Cs (formula: CsNO₃) And dissolving the mixture in deionized water in sequence to obtain a metal ion mixed solution I after complete dissolution. And 2.2 mol of ammonium carbamate is dissolved in deionized water, and after complete dissolution, a precipitant solution II is obtained. And (3) carrying out cocurrent feeding on the metal ion mixed solution I and the precipitator solution II, carrying out coprecipitation reaction, and aging at 20 ℃ for 36 hours to obtain mixed slurry III. And (3) feeding the mixed slurry III into a spray dryer, spray-drying to obtain microspherical fine particles, and roasting at the roasting temperature of 650 ℃ for 8 hours to obtain the catalyst.

The prepared catalyst comprises the following components: fe₁₀₀Mn₄₅Zn₁₀Cs₅O_X。

The X-ray diffraction peaks of the catalyst of this example were similar to those of the catalyst of example 1.

2. The catalyst obtained in step 1 was subjected to reduction treatment under the same conditions as in example 1.

3. Catalyst evaluation and reaction conditions were as in example 1.

For convenience of comparison, the composition of the catalyst of this example and the evaluation results are shown in Table 1.

Comparative example 1

1. Preparation of the catalyst

Iron nitrate nonahydrate (molecular formula: Fe (NO): containing 1 mol of Fe₃)₃·9H₂O), a 50% manganese nitrate solution containing 0.45 mol of Mn (molecular formula: mn (NO)₃)₂) Gallium nitrate pentahydrate containing 0.2 mol of Ga (molecular formula: ga (NO)₃)₃·5H₂O), potassium nitrate containing 0.05 mol K (formula: KNO₃) And dissolving the mixture in deionized water in sequence to obtain a metal ion mixed solution I after complete dissolution. Adding 28% concentrated ammonia water containing 4.4 mol of ammonium hydroxide into a proper amount of deionized water for dilution, and obtaining a precipitator solution II after complete dissolution. And (3) carrying out cocurrent feeding on the metal ion mixed solution I and the precipitator solution II, carrying out coprecipitation reaction, and aging at 20 ℃ for 36 hours to obtain mixed slurry III. And (3) feeding the mixed slurry III into a spray dryer, spray-drying the mixed slurry III to form microspherical fine particles, and roasting the microspherical fine particles at the roasting temperature of 650 ℃ for 8 hours to obtain the catalyst of the comparative example.

The composition of the catalyst prepared was as follows: fe₁₀₀Mn₄₅Ga₂₀K₅O_X。

The XRD pattern of the catalyst of this comparative example is shown in FIG. 1.

2. The catalyst obtained in step 1 was subjected to reduction treatment under the same conditions as in example 1.

3. Catalyst evaluation and reaction conditions were as in example 1.

For convenience of comparison, the composition and evaluation results of the catalyst of this comparative example are shown in Table 1.

Comparative example 2

1. Preparation of the catalyst

Iron nitrate nonahydrate (molecular formula: Fe (NO): containing 1 mol of Fe₃)₃·9H₂O), a 50% manganese nitrate solution containing 0.30 mol of Mn (molecular formula: mn (NO)₃)₂) Gallium nitrate pentahydrate containing 0.10 mol of Ga (molecular formula: ga (NO)₃)₃·5H₂O), potassium nitrate containing 0.10 mol K (formula: KNO₃) And dissolving the mixture in deionized water in sequence to obtain a metal ion mixed solution I after complete dissolution. 4.4 mol of urea is dissolved in deionized water to obtain a precipitant solution II. And (3) carrying out cocurrent feeding on the metal ion mixed solution I and the precipitator solution II, carrying out coprecipitation reaction, and aging at 20 ℃ for 36 hours to obtain mixed slurry III. And (3) feeding the mixed slurry III into a spray dryer, spray-drying the mixed slurry III to form microspherical fine particles, and roasting the microspherical fine particles at the roasting temperature of 650 ℃ for 8 hours to obtain the catalyst of the comparative example.

The composition of the catalyst prepared was as follows: fe₁₀₀Mn₃₀Ga₁₀K₁₀O_X。

The X-ray diffraction peaks of the catalyst of this comparative example were similar to those of the catalyst of comparative example 1.

2. The catalyst obtained in step 1 was subjected to reduction treatment under the same conditions as in example 1.

3. Catalyst evaluation and reaction conditions were as in example 1.

For convenience of comparison, the composition and evaluation results of the catalyst of this comparative example are shown in Table 1.

TABLE 1

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and those skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.