CN111036282B

CN111036282B - Supported catalyst, preparation method thereof and method for preparing alpha-olefin from synthesis gas

Info

Publication number: CN111036282B
Application number: CN201811197915.0A
Authority: CN
Inventors: 晋超; 吴玉; 张荣俊; 夏国富; 侯朝鹏; 孙霞; 王薇
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2018-10-15
Filing date: 2018-10-15
Publication date: 2022-09-27
Anticipated expiration: 2038-10-15
Also published as: CN111036282A

Abstract

The present disclosure relates to a supported catalyst, a preparation method thereof and a method for preparing alpha-olefin from synthesis gas, the catalyst comprises a carrier, and an active component and an auxiliary agent loaded on the carrier, wherein the carrier contains a manganese oxide molecular sieve OMS-1, the active component is one or more metal components selected from VIII group metals, and the auxiliary agent is one or more metal components selected from IIB group metals. Compared with the catalyst in the prior art, the supported catalyst has improved catalytic activity and target product selectivity, has the advantages of higher alpha-olefin yield and concentrated product carbon number when being used for preparing alpha-olefin from synthesis gas, and is beneficial to industrial popularization.

Description

Supported catalyst, preparation method thereof and method for preparing alpha-olefin from synthesis gas

Technical Field

The present disclosure relates to a supported catalyst, a method of preparing the same, and a method of preparing alpha-olefins from synthesis gas.

Background

The energy sources in China are in the resource distribution situation of rich coal, much natural gas and oil shortage, and the indirect conversion of coal-based or natural gas into clean and efficient liquid fuel through Fischer-Tropsch (F-T) synthesis is an important aspect of reasonably utilizing resources and is a main technical way for relieving the contradiction between supply and demand of petroleum in China. The process comprises the steps of firstly converting coal or natural gas into synthesis gas, and then preparing the synthesis gas into liquid fuel through F-T synthesis. The F-T synthesis technology comprises two types of high-temperature F-T synthesis and low-temperature F-T synthesis, wherein the operation temperature of the high-temperature F-T synthesis technology is 300-350 ℃, and the operation pressure is about 1.5-2.5 MPa; the operation temperature of the low-temperature F-T synthesis process is 210-250 ℃, and the operation pressure is about 1.5-2.5 MPa. The products synthesized by the high-temperature F-T can be processed to obtain environment-friendly gasoline, diesel oil, solvent oil, olefin and oxygen-containing compounds; the main product paraffin synthesized by low-temperature F-T can be processed into special wax or used for producing high-quality diesel oil and lubricating oil base oil through hydrocracking/isomerization, and naphtha fraction is also an ideal cracking raw material. The traditional Fischer-Tropsch synthesis products mainly comprise straight-chain alkane, olefin, alditol, by-product water and carbon dioxide, the product composition is complex, and the production of more olefin can be realized by adjusting the process conditions and the catalyst composition. Linear alpha-olefins are important organic feedstocks and intermediates for the production of comonomers, lubricant base oils, surfactants, polyolefin resins, plasticizers, dyes, pharmaceutical formulations, and the like. The south Africa Sasol company has built a set of production devices for separating 1-pentene and 1-hexene from F-T synthetic products (rich in alpha-olefin) and successfully put into production, and the process has the greatest advantages that coal is used as a raw material, the 1-pentene and the 1-hexene are used as byproducts for recycling, the industrial production cost is low, and higher benefits are obtained.

The most widely used method for producing alpha-olefins at present is olefin oligomerization, but the method has high production cost and cannot produce linear alpha-olefins with odd carbon numbers and the same market value. The cost of extracting linear 1-hexene from a crude product by a high-temperature F-T Fischer-Tropsch synthesis technology of south Africa Sasol company is less than one third of that of Philips company which adopts an ethylene trimerization method, and meanwhile, high-temperature F-T synthesis can also obtain high-value-added products such as 1-pentene, 1-heptene and the like with odd carbon numbers based on an ASF distribution rule of F-T synthesis products. Therefore, the separation of alpha-olefins from products of the Fischer-Tropsch synthesis is of significant commercial value.

Currently, iron-based catalysts are commonly used in industry to produce olefins in slurry, fixed bed or fluidized bed processes. Under the condition of low-temperature F-T synthesis process, the product has high heavy hydrocarbon content and low olefin content, and is not beneficial to producing alpha-olefin. South africa Sasol corporation uses a high temperature fluidized bed process to produce gasoline and alpha-olefins. Although the process can obtain low-carbon linear alpha-olefin, the carbon number distribution of the product alpha-olefin is too dispersed, the yield is low, and the separation and purification are not facilitated.

Common iron-based F-T synthetic catalysts are mostly prepared by a coprecipitation method: the active components are precipitated, filtered and washed, then mixed with a carrier, pulped, dried and formed, and applied to a slurry bed reactor or a fixed bed reactor. The precipitated iron F-T synthetic catalyst has poor mechanical stability, easy breakage and serious carbon deposit in the reaction process, and active components in a bulk phase are difficult to reduce. Since F-T synthesis is a strong exothermic reaction, when reacting in a fixed bed, the precipitated iron catalyst is difficult to heat in a reactor and is easy to fly, so that the catalyst is quickly deactivated. The supported iron-based catalyst has good stability, uniform distribution of active components, high activity and long service life.

CN102408908A discloses a method for producing linear alpha-olefins with various carbon numbers by solvent phase fischer-tropsch synthesis. The polar solvent is used as a reaction medium, the traditional granular Fischer-Tropsch synthesis catalyst is suspended or soaked in the polar solvent phase for Fischer-Tropsch synthesis reaction, and the generated hydrocarbon products are insoluble in the polar solvent and are subjected to self phase separation. However, the linear alpha-olefins obtained using this process are too carbon dispersive. CN103525456A discloses a method for preparing synthetic hydrocarbon from coal-made olefin, which is to put light oil part containing alpha-olefin and alkane in the coal-made olefin in AlCl ₃ Under the action of the catalyst, a synthetic hydrocarbon base oil product used as high-quality lubricating oil is prepared. US4579986 discloses a preparation C ₁₀ -C ₂₀ Method for producing olefins by reacting CO and H with a cobalt-based catalyst ₂ Conversion into a mixture of n-alkanes, analysis C ₂₀ ⁺ The aboveA fraction which is converted into C by mild thermal cracking ₁₀ -C ₂₀ Hydrocarbon mixtures of olefins. However, in this process, the alpha-olefin content is low.

Therefore, it is very practical to develop a catalyst that can increase the yield of α -olefins and concentrate the carbon number of the product.

Disclosure of Invention

The purpose of the present disclosure is to provide a supported catalyst, a preparation method thereof, and a method for preparing alpha-olefin from synthesis gas, so as to overcome the defects of low alpha-olefin yield and excessive dispersion of carbon number of the product of the existing catalyst.

To achieve the above object, a first aspect of the present disclosure: a supported catalyst is provided, which comprises a carrier, and an active component and an auxiliary agent which are loaded on the carrier, wherein the carrier contains a manganese oxide molecular sieve OMS-1, the active component is one or more of metal components selected from VIII group metals, and the auxiliary agent is one or more of metal components selected from IIB group metals.

Optionally, the carrier is 12-94 wt%, the active component is 1-70 wt%, and the auxiliary agent is 1-30 wt% calculated by metal element based on the dry weight of the catalyst.

Optionally, the carrier is contained in an amount of 30 to 91 wt%, the active component is contained in an amount of 2 to 50 wt%, and the auxiliary agent is contained in an amount of 2 to 25 wt%, calculated as the metal element, based on the dry weight of the catalyst.

Optionally, the active component is an Fe component and/or a Co component; the auxiliary agent is a Zn component and/or a Cd component.

Optionally, the weight ratio of the active component to the auxiliary agent is 1: (0.2 to 5), preferably 1: (0.3-3).

In a second aspect of the present disclosure: there is provided a process for preparing a supported catalyst according to the first aspect of the present disclosure, the process comprising: and loading the active component and the auxiliary agent on the carrier.

Optionally, the step of loading the active ingredient and adjuvant on the carrier comprises: contacting impregnation liquid containing an active component precursor and an auxiliary agent precursor with a carrier for impregnation;

the impregnation conditions include: the temperature is 10-80 ℃, and preferably 20-60 ℃; the time is 0.1 to 3 hours, preferably 0.5 to 1 hour.

Optionally, the active component precursor is nitrate, citrate, sulfate or chloride of the active component, or a combination of two or three thereof; the auxiliary agent precursor is nitrate, sulfate, carbonate or chloride of the auxiliary agent, or a combination of two or three of the nitrate, the sulfate, the carbonate or the chloride.

Optionally, the method further comprises the steps of drying and roasting the loaded material;

the drying conditions include: the temperature is 80-350 ℃, and preferably 100-300 ℃; the time is 1-24 hours, preferably 2-12 hours;

the roasting conditions comprise: the temperature is 250-900 ℃, preferably 300-850 ℃, and more preferably 350-800 ℃; the time is 0.5 to 12 hours, preferably 1 to 8 hours, and more preferably 2 to 6 hours.

A third aspect of the disclosure: there is provided a process for producing alpha-olefins from synthesis gas, the process comprising the steps of:

(1) carrying out reduction treatment on the initial catalyst in a reducing atmosphere containing hydrogen to obtain a reduced catalyst;

(2) contacting the synthesis gas with the catalyst obtained in the step (1) after reduction treatment for reaction;

wherein the initial catalyst is a supported catalyst according to the first aspect of the present disclosure.

Optionally, in step (1), the reducing conditions include: the airspeed is 1000~20000h ^-1 Preferably 2000 to 10000h ^-1 (ii) a The temperature is 200-600 ℃, and preferably 250-500 ℃; the heating rate is 1-30 ℃/min, preferably 5-15 ℃/min; the time is 1-20 h, preferably 2-10 h;

in the step (2), the reaction conditions include: the inverse ofThe method is carried out in a fixed bed reactor, the reaction temperature is 280-320 ℃, the reaction pressure is 0.5-8 MPa, and H in the synthesis gas ₂ The molar ratio of the carbon dioxide to CO is (0.4-2.5): 1, the space velocity of the synthesis gas is 2000-20000 h ^-1 。

Through the technical scheme, compared with the catalyst in the prior art, the supported catalyst disclosed by the invention has the advantages that the selectivity of a target product is improved, the yield of alpha-olefin is higher and the carbon number of the product is concentrated (the carbon number is concentrated on C) when the supported catalyst is used for preparing the alpha-olefin from synthesis gas ₅ -C ₁₅ And the prior art is generally at C ₅ -C ₃₀ Distribution) and is beneficial to industrial popularization.

Additional features and advantages of the present disclosure will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure without limiting the disclosure. In the drawings:

FIG. 1 is an XRD spectrum of support OMS-1 prepared in the examples.

Detailed Description

The following detailed description of specific embodiments of the present disclosure is provided in connection with the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present disclosure, are given by way of illustration and explanation only, not limitation.

The first aspect of the disclosure: a supported catalyst is provided, which comprises a carrier, and an active component and an auxiliary agent which are loaded on the carrier, wherein the carrier contains a manganese oxide molecular sieve OMS-1, the active component is one or more of metal components selected from VIII group metals, and the auxiliary agent is one or more of metal components selected from IIB group metals.

As a result of intensive studies, the inventors of the present disclosure found that when a specific manganese oxide molecular sieve OMS-1 is used as a carrier and a group VIII metal component and a group IIB metal component are used as an active component and an auxiliary agent, respectively, the resulting catalyst exhibitsExcellent selectivity of target products. When the catalyst is used in the reaction of preparing alpha-olefin from synthesis gas, higher alpha-olefin yield can be obtained, and the carbon number of the product is concentrated (the carbon number is concentrated on C) ₅ -C ₁₅ And the prior art is generally at C ₅ -C ₃₀ Distribution).

According to the present disclosure, the carrier may be present in an amount of 12 to 94 wt%, the active component may be present in an amount of 1 to 70 wt%, and the auxiliary agent may be present in an amount of 1 to 30 wt%, based on the dry weight of the catalyst, in terms of the metal element. In order to further improve the selectivity of the target product of the catalyst, preferably, the content of the carrier is 30-91 wt% based on the dry weight of the catalyst, the content of the active component is 2-50 wt% and the content of the auxiliary agent is 2-25 wt% based on the metal element; more preferably, the carrier is contained in an amount of 60-83 wt%, the active component is contained in an amount of 8-30 wt%, and the auxiliary agent is contained in an amount of 3-12 wt%, based on the dry weight of the catalyst.

According to the present disclosure, the ratio of the active component to the auxiliary agent has a certain influence on the catalytic effect of the catalyst. In the present disclosure, the weight ratio of the active component to the auxiliary agent may be 1: (0.2 to 5), preferably 1: (0.3-3).

Further, the active component may be an Fe component and/or a Co component, most preferably an Fe component. The auxiliary agent can be a Zn component and/or a Cd component, and is most preferably a Zn component.

A second aspect of the disclosure: there is provided a process for preparing a supported catalyst according to the first aspect of the present disclosure, the process comprising: and loading the active component and the auxiliary agent on the carrier.

In accordance with the present disclosure, manganese oxide molecular sieve OMS-1 may be used as the support either directly or after mixing with a suitable adjuvant (e.g., zirconium metal, etc.) and using the resulting mixture as the support. Oxides of manganese molecular sieve OMS-1 is commercially available or can be prepared by methods known in the art, and can be prepared, for example, by the steps of:

a. mixing a first aqueous solution containing a reduced manganese compound and an inorganic salt of magnesium with a second alkaline aqueous solution containing an oxidized manganese compound, and carrying out an aging reaction at 30-90 ℃, preferably at 40-70 ℃ for 10-50 h, preferably 15-40 h to obtain a manganese oxide molecular sieve precursor;

b. and c, mixing the manganese oxide molecular sieve precursor obtained in the step a with a third aqueous solution containing inorganic salt of magnesium, performing crystallization reaction at 100-200 ℃, preferably 120-180 ℃ for 12-72 hours, preferably 24-60 hours, and collecting solids.

Further, the oxidized manganese compound and the reduced manganese compound are relative; the oxidized manganese compound is generally referred to as containing a relatively high valence state of manganese (e.g., Mn) ⁷⁺ 、Mn ⁶⁺ Etc.), for example, potassium permanganate or potassium manganate; the reduced manganese compound is generally referred to as containing relatively low levels of manganese (e.g., Mn) ²⁺ ) The compound of (2) may be, for example, manganese sulfate, manganese nitrate or manganese chloride. The inorganic salt of magnesium may be magnesium chloride or magnesium nitrate. The weight ratio of the oxidized manganese compound, the reduced manganese compound and the inorganic salt of magnesium may be 1: (1-10): (0.1-5). The base in the alkaline second aqueous solution may be a common inorganic base, and may be, for example, sodium hydroxide, potassium hydroxide, or the like; the alkali concentration of the alkali second aqueous solution may be 1 to 20% by weight. Further, the preparing step may further include: in the step a, the first aqueous solution and the alkaline second aqueous solution are respectively heated to 30-90 ℃, preferably 40-70 ℃, and then mixed. Through the steps, pure phase octahedral manganese oxide molecular sieve OMS-1 with XRD spectrogram conforming to JCPDS No.38-475 can be prepared.

The method for supporting is not particularly limited in the present disclosure, and may be a method conventionally used in the art, for example, an impregnation method or a coprecipitation method may be used, and an impregnation method is preferred. The impregnation can be one-time impregnation or step-by-step impregnation, wherein the step-by-step impregnation can be to load the active component and the auxiliary agent onto the carrier sequentially through impregnation, or to dissolve the active component and the auxiliary agent together to form an impregnation solution, and to impregnate the carrier twice or more times with the impregnation solution.

In an alternative embodiment of the present disclosure, the step of loading the active ingredient and the adjuvant on the carrier may comprise: and (3) contacting the impregnation liquid containing the active component precursor and the auxiliary agent precursor with the carrier for impregnation. The impregnation may be an isometric impregnation method or a saturation impregnation method. The conditions of the impregnation may be conventional, for example, the conditions of the impregnation may include: the temperature is 10-80 ℃, and preferably 20-60 ℃; the time is 0.1 to 3 hours, preferably 0.5 to 1 hour.

Wherein, the active component precursor refers to a compound containing the active component, such as nitrate, citrate, sulfate or chloride which can be the active component, or a combination of two or three of the above; for example, when the active component is an Fe component, the active component precursor may be ferric nitrate, ferric citrate, ferric chloride, or the like. The auxiliary agent precursor is a compound containing an auxiliary agent, such as nitrate, sulfate, carbonate or chloride which can be the auxiliary agent, or a combination of two or three of the nitrate, the sulfate, the carbonate or the chloride; for example, when the auxiliary is a Zn component, the auxiliary precursor may be zinc nitrate, zinc chloride, zinc carbonate, or the like. The impregnation liquid is a solution obtained by dissolving an active component precursor and an auxiliary agent precursor in a solvent. Wherein, the solvent can be, for example, water, ethanol, diethyl ether, etc., and the amount of the solvent can be conventional, and the disclosure is not particularly limited.

In the above embodiment, the carrier, the active component precursor, and the auxiliary agent precursor are used in amounts such that the prepared catalyst contains 12 to 94 wt%, preferably 30 to 91 wt% of the carrier based on the dry weight of the catalyst, the active component is 1 to 70 wt%, preferably 2 to 50 wt% of the carrier based on the metal element, and the auxiliary agent is 1 to 30 wt%, preferably 2 to 25 wt%.

According to the present disclosure, the method further comprises the step of drying and roasting the loaded material. The drying and calcining steps are conventional steps in preparing catalysts, and the present disclosure is not particularly limited. For example, the drying conditions may include: the temperature is 80-350 ℃, and preferably 100-300 ℃; the time is 1 to 24 hours, preferably 2 to 12 hours. The conditions for the firing may include: the temperature is 250-900 ℃, preferably 300-850 ℃, and more preferably 350-800 ℃; the time is 0.5 to 12 hours, preferably 1 to 8 hours, and more preferably 2 to 6 hours.

(2) contacting the synthesis gas with the reduced catalyst obtained in the step (1) for reaction;

According to the disclosure, in the step (1), the supported catalyst disclosed by the disclosure is subjected to reduction treatment, so that the active component can be subjected to reduction activation, and the catalytic effect of the catalyst can be improved. The conditions of the reduction treatment may include: the airspeed is 1000~20000h ^-1 Preferably 2000 to 10000h ^-1 (ii) a The temperature is 100-800 ℃, preferably 200-600 ℃, and more preferably 250-500 ℃; the time is 0.5 to 72 hours, preferably 1 to 36 hours, and more preferably 2 to 24 hours. The reducing atmosphere may be pure hydrogen atmosphere or a mixed atmosphere of hydrogen and an inert gas (such as nitrogen, argon, or helium), and the hydrogen partial pressure may be 0.1 to 4MPa, preferably 0.1 to 2 MPa.

According to the present disclosure, the syngas contains CO and H ₂ And optionally N ₂ . The synthesis gas is contacted with the supported catalyst for reaction, the ready synthesis gas is contacted with the supported catalyst for reaction, or CO and H are contacted according to the proportion ₂ Respectively introducing the two into a reactor to contact with a catalyst for reaction.

According to the present disclosure, in step (2), the conditions of the reaction may include: the reaction temperature is 280-320 DEG CThe reaction pressure is 0.5-8 MPa, preferably 1-5 MPa; h in the synthesis gas ₂ The molar ratio of the carbon dioxide to CO is (0.4-2.5): 1, preferably (0.6-2.5): 1, more preferably (0.8 to 2.2): 1; the space velocity of the synthesis gas is 2000-20000 h ^-1 . In a preferred case, the reaction can be carried out in a fixed bed reactor. Wherein, the pressure all refers to gauge pressure, and the airspeed all refers to volume airspeed. By mixing CO and H in proportion of synthesis gas ₂ When the gas is respectively fed into the reactor to contact with the catalyst for reaction, the space velocity of the synthetic gas is CO and H ₂ The aggregate space velocity of (a).

The present disclosure will be described in further detail below by way of examples, but the present disclosure is not limited thereto.

In the following examples and comparative examples:

the contents of the active components and the auxiliary agents were measured by an X-ray fluorescence spectrum analysis method RIPP 132-90 (petrochemical analysis method (RIPP test method), Yangchini, Kangying, Wu Wenhui ed, science Press, first edition of 9 months in 1990, p 371-379).

In the examples, the preparation method of the carrier manganese oxide molecular sieve OMS-1 comprises the following steps: dissolving 2.014g of anhydrous manganese chloride and 0.636g of magnesium chloride hexahydrate in 70ml of deionized water, heating and stirring in a water bath at 50 ℃ to fully dissolve the anhydrous manganese chloride and the magnesium chloride hexahydrate to obtain a first aqueous solution; dissolving 8.2g of sodium hydroxide in 70g of deionized water, adding 1.012g of potassium permanganate into the solution, and heating and stirring the solution in a water bath at 50 ℃ to fully dissolve the potassium permanganate to obtain an alkaline second aqueous solution; dropwise adding the first aqueous solution into an alkaline second aqueous solution, stirring in a water bath at 50 ℃ for 6 hours, filtering the obtained precipitate, and washing with water at 80 ℃ for 3 times to obtain a manganese oxide molecular sieve precursor; adding 42.63g of magnesium chloride hexahydrate into 120g of deionized water to obtain a third aqueous solution, adding a manganese oxide molecular sieve precursor into the third aqueous solution, fully stirring, transferring the mixture into a 250ml hydrothermal kettle, carrying out hydrothermal crystallization at 160 ℃ for 36h, and collecting a solid product to obtain a carrier manganese oxide molecular sieve OMS-1, wherein an XRD spectrogram of the carrier manganese oxide molecular sieve OMS-1 is shown in a figure 1, and the carrier manganese oxide molecular sieve OMS-1 is a pure-phase octahedral manganese oxide molecular sieve OMS-1 conforming to JCPDS No. 38-475.

Example 1

4.04g of ferric nitrate nonahydrate and 2.98g of zinc nitrate hexahydrate are dissolved in 10mL of deionized water, and the mixture is heated, stirred and mixed uniformly in a water bath at 50 ℃ to obtain an impregnation liquid. The impregnation liquid was mixed with 10g of a carrier manganese oxide molecular sieve OMS-1, sufficiently stirred and impregnated at 20 ℃ for 1h, then placed in an oven at 120 ℃ for drying for 5h, and calcined at 400 ℃ for 3h to obtain catalyst A1 prepared in this example, wherein the catalyst A1 had a composition of 10 wt% Fe-10 wt% Zn/OMS-1, calculated as metal elements and based on the dry weight of the catalyst.

Example 2

8.08g of ferric nitrate nonahydrate and 2.98g of zinc nitrate hexahydrate are dissolved in 10mL of deionized water, heated in a water bath at 50 ℃, stirred and mixed uniformly to obtain an impregnation liquid. The impregnation liquid was mixed with 10g of a carrier manganese oxide molecular sieve OMS-1, sufficiently stirred and impregnated at 20 ℃ for 1h, then placed in an oven at 120 ℃ for drying for 5h, and calcined at 400 ℃ for 3h to obtain catalyst A2 prepared in this example, wherein the catalyst A2 had a composition of 20 wt% Fe-10 wt% Zn/OMS-1, calculated as metal elements and based on the dry weight of the catalyst.

Example 3

5.91g of cobalt nitrate hexahydrate and 1.36g of cadmium carbonate are dissolved in 10mL of deionized water, and the mixture is heated, stirred and mixed uniformly in a water bath at 50 ℃ to obtain an impregnation liquid. The impregnation liquid is taken and mixed with 10g of carrier manganese oxide molecular sieve OMS-1, the mixture is fully stirred and impregnated for 1h at the temperature of 20 ℃, then the mixture is placed in an oven at the temperature of 120 ℃ to be dried for 5h and roasted for 3h at the temperature of 400 ℃, and the catalyst A3 prepared in the embodiment is obtained, wherein the catalyst A3 comprises 20 wt% of Co and 10 wt% of Cd/OMS-1 based on the weight of metal elements and the weight of a dry base of the catalyst.

Example 4

4.04g of ferric nitrate nonahydrate, 2.12g of cobalt nitrate hexahydrate and 1.75g of zinc nitrate hexahydrate are dissolved in 10mL of deionized water, and the mixture is heated and stirred in a water bath at 50 ℃ and is uniformly mixed to obtain a steeping liquor. Mixing the impregnation liquid with 10g of a carrier manganese oxide molecular sieve OMS-1, fully stirring and impregnating for 1h at 20 ℃, then placing the mixture in an oven at 120 ℃ for drying for 5h, and roasting for 3h at 400 ℃ to obtain the catalyst A4 prepared in the embodiment, wherein the composition of the catalyst A4 is 10 wt% of Fe-2 wt% of Co-5 wt% of Zn/OMS-1 based on the metal elements and the dry basis weight of the catalyst.

Example 5

Dissolving 2.02g of ferric nitrate nonahydrate and 5.83g of zinc nitrate hexahydrate in 10mL of deionized water, heating in a water bath at 50 ℃, stirring and mixing uniformly to obtain a steeping fluid. The impregnation liquid was mixed with 10g of a carrier manganese oxide molecular sieve OMS-1, sufficiently stirred and impregnated at 20 ℃ for 1h, then placed in an oven at 120 ℃ for drying for 5h, and calcined at 400 ℃ for 3h to obtain catalyst A5 prepared in this example, wherein the composition of catalyst A5 was 5 wt% Fe-25 wt% Zn/OMS-1 based on the weight of the metal elements on a dry basis of the catalyst.

Example 6

6.17g of ferric nitrate nonahydrate and 1.68g of zinc nitrate hexahydrate are dissolved in 10mL of deionized water, and the mixture is heated and stirred in a water bath at 50 ℃ and is uniformly mixed to obtain a steeping fluid. Mixing the impregnation liquid with 10g of a manganese oxide molecular sieve OMS-1 carrier, fully stirring and impregnating for 1h at 20 ℃, then placing the mixture in an oven at 120 ℃ for drying for 5h, and roasting for 3h at 400 ℃ to obtain the catalyst A6 prepared in the embodiment, wherein the catalyst A6 comprises 16 wt% of Fe-4 wt% of Zn/OMS-1 in terms of metal elements and based on the dry weight of the catalyst.

Example 7

Dissolving 2.02g of ferric nitrate nonahydrate and 4.67g of zinc nitrate hexahydrate in 10mL of deionized water, heating in a water bath at 50 ℃, and stirring and mixing uniformly to obtain an impregnation liquid. The impregnation liquid was mixed with 10g of a carrier manganese oxide molecular sieve OMS-1, sufficiently stirred and impregnated at 20 ℃ for 1h, then placed in an oven at 120 ℃ for drying for 5h, and calcined at 400 ℃ for 3h to obtain catalyst A7 prepared in this example, wherein the composition of catalyst A7 was 5 wt% Fe-15 wt% Zn/OMS-1 based on the weight of the metal elements on a dry basis of the catalyst.

Example 8

0.41g of ferric nitrate nonahydrate and 9.74g of zinc nitrate hexahydrate are dissolved in 10mL of deionized water, and the mixture is heated and stirred in a water bath at 50 ℃ and is uniformly mixed to obtain a steeping fluid. The impregnation liquid is taken and mixed with 10g of carrier manganese oxide molecular sieve OMS-1, the mixture is fully stirred and impregnated for 1h at the temperature of 20 ℃, then the mixture is placed in an oven at the temperature of 120 ℃ to be dried for 5h and roasted for 3h at the temperature of 400 ℃, and the catalyst A8 prepared in the embodiment is obtained, wherein the composition of the catalyst A8 is 1 weight percent of Fe to 30 weight percent of Zn/OMS-1 based on the metal element and the weight of the dry basis of the catalyst.

Comparative example 1

4.04g of ferric nitrate nonahydrate is dissolved in 10mL of deionized water, heated in a water bath at 50 ℃, stirred and mixed uniformly to obtain a steeping fluid. Mixing the impregnation liquid with 10g of carrier manganese oxide molecular sieve OMS-1, fully stirring and impregnating for 1h at 20 ℃, then placing in an oven at 120 ℃ for drying for 5h, and roasting for 3h at 400 ℃ to obtain a catalyst D1, wherein the catalyst D1 comprises 10 wt% of Fe/OMS-1 based on the metal elements and the dry basis weight of the catalyst.

Comparative example 2

Dissolving 2.98g of zinc nitrate hexahydrate in 10mL of deionized water, heating in a water bath at 50 ℃, stirring and mixing uniformly to obtain an impregnation liquid. Mixing the impregnation liquid with 10g of a carrier manganese oxide molecular sieve OMS-1, fully stirring and impregnating for 1h at 20 ℃, then placing the mixture in an oven at 120 ℃ for drying for 5h, and roasting for 3h at 400 ℃ to obtain a catalyst D2, wherein the catalyst D2 comprises 10 wt% of Zn/OMS-1 in terms of metal elements and based on the dry weight of the catalyst.

Test examples

The catalysts prepared in examples 1 to 8 and comparative examples 1 to 2 were tested for catalytic activity when used to catalyze the production of alpha-olefins from synthesis gas.

Charging the initial catalyst into a fixed bed reactor, and introducing H into the fixed bed reactor ₂ The pressure of the reactor is adjusted to be 0.1MPa, and the space velocity is adjusted to be 10000h ^-1 Raising the temperature to 400 ℃ at a heating rate of 10 ℃/min, and keeping the temperature for 4h for reduction treatment.

After the reduction treatment is finished, the temperature of the reactor is reduced to 320 ℃, synthetic gas is introduced to start the reaction, and the space velocity is 5000h ^-1 The pressure is 1.5MPa, and the composition of the synthesis gas is H ₂ :CO:N ₂ The composition of the off-gas was analyzed by on-line gas chromatography at 56:28:16 (volume ratio). The results obtained after 50 hours of reaction are shown in Table 1.

Wherein:

conversion of CO (X) _CO )、CH ₄ Selectivity of (2)

CO ₂ Selectivity of (2)

Selectivity to alpha-olefin (S) _{Alpha-olefins} ) And C ₅ Above (C) ₅₊ ) Selectivity of hydrocarbons

Respectively calculated by the following formula:

wherein, V ₁ 、V ₂ Respectively representing the volume of feed gas entering the reaction system and the volume of tail gas flowing out of the reaction system in a certain time period under a standard condition; c. C _1,CO 、c _2,CO Respectively representing the molar contents of CO in the raw material gas and the tail gas. n is _con In terms of the number of moles of CO participating in the reaction,

to generate CO ₂ The number of moles of (a) to (b),

to generate CH ₄ Mole number of (b), n _{Alpha-olefins} To produce the moles of alpha-olefin,

to generate CH ₄ 、C ₂ Hydrocarbons, C ₃ Hydrocarbons and C ₄ The sum of the moles of hydrocarbons.

TABLE 1

Note: the oil phase product is derived from C ₅ ⁺ The oil phase product contains components such as alkane, alpha-olefin, isomeric hydrocarbon, oxygen-containing compound and the like.

As can be seen from table 1, when the supported catalyst of the present disclosure is used in a reaction for preparing α -olefin from synthesis gas, the conversion rate of carbon monoxide is high, the selectivity of α -olefin is high, and the carbon number of the product is concentrated.

The preferred embodiments of the present disclosure are described in detail above with reference to the accompanying drawings, however, the present disclosure is not limited to the specific details in the above embodiments, and various simple modifications may be made to the technical solution of the present disclosure within the technical idea of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.

It should be noted that, in the foregoing embodiments, various features described in the above embodiments may be combined in any suitable manner, and in order to avoid unnecessary repetition, various combinations that are possible in the present disclosure are not described again.

In addition, any combination of various embodiments of the present disclosure may be made, and the same should be considered as the disclosure of the present disclosure, as long as it does not depart from the spirit of the present disclosure.

Claims

1. A method for preparing C-enriched carbon from synthesis gas ₅ ~C ₁₅ The supported catalyst of alpha-olefin is characterized by comprising a carrier, and an active component and an auxiliary agent which are loaded on the carrier, wherein the carrier contains a manganese oxide molecular sieve OMS-1, the active component is one or more metal components selected from group VIII metals, and the auxiliary agent is one or more metal components selected from group IIB metals.

2. The supported catalyst according to claim 1, wherein the carrier is present in an amount of 12 to 94 wt%, the active component is present in an amount of 1 to 70 wt%, and the auxiliary is present in an amount of 1 to 30 wt%, in terms of metal element, based on the dry weight of the supported catalyst.

3. A supported catalyst according to claim 2, wherein the carrier is present in an amount of 30 to 91 wt%, based on the dry weight of the supported catalyst, the active component is present in an amount of 2 to 50 wt%, and the promoter is present in an amount of 2 to 25 wt%, based on the metal element.

4. The supported catalyst of claim 1, wherein the active component is an Fe component and/or a Co component; the auxiliary agent is a Zn component and/or a Cd component.

5. The supported catalyst according to claim 1, wherein the weight ratio of the active component to the promoter is 1: (0.2-5).

6. The supported catalyst according to claim 5, wherein the weight ratio of the active component to the promoter is 1: (0.3-3).

7. A process for preparing a supported catalyst according to any one of claims 1 to 6, comprising: and loading the active component and the auxiliary agent on the carrier.

8. The method of claim 7, wherein the step of loading the active ingredient and adjuvant on the carrier comprises: contacting impregnation liquid containing an active component precursor and an auxiliary agent precursor with a carrier for impregnation;

the impregnation conditions include: the temperature is 10-80 ℃ and the time is 0.1-3 h.

9. The method of claim 8, wherein the conditions of the impregnating comprise: the temperature is 20-60 ℃, and the time is 0.5-1 h.

10. The method of claim 8, wherein the active ingredient precursor is a nitrate, citrate, sulfate, or chloride of the active ingredient, or a combination of two or three thereof;

the auxiliary agent precursor is nitrate, sulfate, carbonate or chloride of the auxiliary agent, or a combination of two or three of the nitrate, the sulfate, the carbonate or the chloride.

11. The method according to claim 7, wherein the method further comprises the steps of drying and roasting the material obtained after loading;

the drying conditions include: the temperature is 80-350 ℃, and the time is 1-24 hours;

the roasting conditions comprise: the temperature is 250-900 ℃, and the time is 0.5-12 hours.

12. The method of claim 11, wherein the drying conditions comprise: the temperature is 100-300 ℃, and the time is 2-12 hours;

the roasting conditions comprise: the temperature is 300-850 ℃, and the time is 1-8 hours.

13. The method of claim 12, wherein the firing conditions include: the temperature is 350-800 ℃, and the time is 2-6 hours.

14Preparation of carbon number concentrated in C from synthesis gas ₅ ~C ₁₅ The process for producing alpha-olefins, the process comprising the steps of:

wherein the initial catalyst is a supported catalyst according to any one of claims 1 to 6.

15. The method according to claim 14, wherein in step (1), the conditions of the reduction treatment include: the airspeed is 1000~20000h ^-1 The temperature is 100-800 ℃, and the time is 0.5-72 h;

in the step (2), the reaction conditions include: the reaction is carried out in a fixed bed reactor, the reaction temperature is 280-320 ℃, the reaction pressure is 0.5-8 MPa, and H in the synthesis gas ₂ The molar ratio of the carbon dioxide to CO is (0.4-2.5): 1, the space velocity of the synthesis gas is 2000-20000 h ^-1 。

16. The method according to claim 15, wherein in step (1), the conditions of the reduction treatment comprise: the airspeed is 2000-10000 h ^-1 The temperature is 200-600 ℃, and the time is 1-36 h.