Composite carrier and preparation method and application thereof, iron catalyst and preparation method and application thereof, and method for preparing low-carbon olefin from synthesis gas

Abstract

The invention relates to preparation and application of a catalyst, in particular to a composite carrier, a preparation method and application of the composite carrier, an iron catalyst, a preparation method and application of the iron catalyst and a method for preparing low-carbon olefin from synthesis gas. The composite carrier comprises IVB-group metal oxide, lanthanide metal oxide and IIIA-group metal oxide; mesopores and macropores in the composite carrier account for 50-80% of the total pores. The composite carrier comprises an IVB group metal oxide, a lanthanide series metal oxide and an IIIA group metal oxide, mesopores and macropores of the composite carrier account for 50-80% of total pores, the catalyst is used for a reaction for directly preparing low-carbon olefin from synthesis gas, the selectivity of low-carbon olefin can be improved, the selectivity of methane can be reduced, and an excellent technical effect is achieved.

Description

Technical Field

[0001] The present invention relates to the preparation and application of a catalyst, and in particular to a composite carrier and a preparation method and application thereof, an iron catalyst and a preparation method and application thereof, and a method for preparing light olefins from synthesis gas. Background Art

[0002] The direct production of low-carbon olefins (with carbon atoms ≤ 4) from syngas through the Fischer-Tropsch synthesis reaction has the advantages of wide raw material sources and short process routes, and can provide an alternative to steam cracking technology based on high-cost raw materials such as naphtha. The research on catalysts for the Fischer-Tropsch synthesis reaction to produce low-carbon olefins mainly focuses on inexpensive iron catalysts. The performance of the catalyst can be significantly improved through the support effect of the catalyst active components and carriers, as well as the addition of certain metal additives.

[0003] CN106378135A discloses an iron-based catalyst for preparing light olefins from synthesis gas. An α-Al2O3 carrier is first prepared by a solution combustion method, and then an active component Fe and an additive Na, K or Mg are loaded onto the α-Al2O3 carrier by an impregnation combustion method to prepare an iron-based catalyst. The iron-based catalyst is used in the reaction of preparing light olefins from synthesis gas. Under the conditions of a reaction pressure of 20 bar, a reaction temperature of 360°C and a mass space velocity of 4000 mL / (g·h), when the CO conversion rate of the catalyst is 94.8%, the light olefin selectivity is 68.2% and the methane selectivity is 17.3%. However, the carbon monoxide conversion rate and the light olefin selectivity of the catalyst are both low, and the methane selectivity is very high. Summary of the invention

[0004] The purpose of the present invention is to overcome the problems of low selectivity for light olefins and high selectivity for methane in the direct reaction of synthesis gas to light olefins in the prior art, and to provide a composite carrier and its preparation method and application, an iron catalyst and its preparation method and application, and a method for preparing light olefins from synthesis gas. When the composite carrier iron catalyst is used in the direct reaction of synthesis gas to light olefins, it has the advantages of high selectivity for light olefins and low selectivity for methane.

[0005] In order to achieve the above objectives, the first aspect of the present invention provides a composite carrier, which comprises Group IVB metal oxides, lanthanide metal oxides and Group IIIA metal oxides; the proportion of mesopores and macropores in the composite carrier accounts for 50-80% of the total pores.

[0006] The second aspect of the present invention provides a method for preparing the composite carrier according to the first aspect of the present invention, the preparation method comprising:

[0007] S1. mixing a lanthanide metal precursor, a Group IIIA metal precursor and an organic acid in a solvent to form a mixed solution A;

[0008] S2. The Group IVB metal oxide and the dispersant are added to the mixed solution A for a second mixing to form a sol;

[0009] S3. The sol is desolventized to form a gel, the solvent is removed, the gel is dried, and a first calcination is performed.

[0010] The third aspect of the present invention provides the use of the composite carrier prepared by the method for preparing the composite carrier described in the first aspect and the second aspect of the present invention in preparing a catalyst.

[0011] The fourth aspect of the present invention provides an iron catalyst, which includes an active component and a carrier, wherein the active component includes elemental iron, transition metal elements, and lanthanide metal elements.

[0012] The fifth aspect of the present invention provides a method for preparing the iron catalyst according to the fourth aspect of the present invention, the method comprising:

[0013] (1) preparing a composite carrier according to the preparation method described in the second aspect of the present invention;

[0014] (2) Dissolving soluble salts corresponding to the iron source, transition metal source and lanthanide metal source to obtain a mixed solution B, subjecting the mixed solution B to a first contact impregnation with the composite support to obtain a catalyst precursor, drying the mixture, and performing a second calcination.

[0015] The sixth aspect of the present invention provides the use of the iron catalyst described in the fourth and fifth aspects of the present invention in the reaction of preparing light olefins from synthesis gas.

[0016] The seventh aspect of the present invention provides a method for preparing low-carbon olefins from synthesis gas, which comprises: subjecting the synthesis gas to a second contact reaction with a catalyst; the catalyst is a reduced iron catalyst prepared by a composite carrier prepared by the preparation method described in the first and second aspects of the present invention.

[0017] Through the above technical solution, the present invention has the following beneficial effects:

[0018] The composite carrier of the present invention comprises Group IVB metal oxides, lanthanide metal oxides and Group IIIA metal oxides; the proportion of mesopores and macropores in the composite carrier to the total pores is 50-80%, and the iron catalyst prepared therefrom has a larger pore size and specific surface area, which is conducive to better dispersion of active components and rapid separation of product molecules. It is used for the direct production of light olefins from synthesis gas, can improve the selectivity of light olefins, reduce the selectivity of methane, and achieves excellent technical effects. DETAILED DESCRIPTION

[0019] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0020] The invention provides a composite carrier, which comprises Group IVB metal oxide, lanthanide metal oxide and Group IIIA metal oxide; in the composite carrier, the proportion of mesopores and macropores to total pores is 50-80%.

[0021] The iron catalyst prepared from the composite carrier of the present invention has a larger pore size and specific surface area, which is conducive to better dispersion of active components and rapid separation of product molecules. It is used for the direct production of light olefins from synthesis gas, can improve the selectivity of light olefins, reduce methane selectivity, and achieve excellent technical effects.

[0022] According to a particularly preferred embodiment of the present invention, the proportion of mesopores and macropores in the composite carrier to the total pores is 55-75%. By adopting the aforementioned preferred embodiment, the active components in the catalyst can be further dispersed better and the product molecules can be quickly separated. When used for the direct production of light olefins from synthesis gas, the selectivity of light olefins can be improved and the selectivity of methane can be reduced, achieving excellent technical effects.

[0023] In the present invention, the weight proportions of the components in the composite carrier can be conventionally selected in the art.

[0024] According to a preferred embodiment of the present invention, based on 100 parts by weight, in the composite carrier, the weight proportion of the Group IVB metal oxide is 30-75 parts, the weight proportion of the lanthanide metal oxide is 20-50 parts, and the weight proportion of the Group IIIA metal oxide is 5-20 parts.

[0025] By adopting the aforementioned preferred implementation, the active components in the catalyst can be further dispersed better and the product molecules can be quickly separated. It can be used for the direct production of light olefins from synthesis gas, improve the selectivity of light olefins, reduce the selectivity of methane, and achieve excellent technical effects.

[0026] In the present invention, the Group IVB metal oxide in the composite carrier can be a conventional choice in the art. According to a preferred embodiment of the present invention, the Group IVB metal oxide in the composite carrier includes at least one of titanium oxide and / or zirconium oxide. In the present invention, titanium oxide is used as an example in the embodiment, but the present invention is not limited to this scope. By adopting the aforementioned preferred embodiment, the better dispersion of active components in the catalyst and the rapid separation of product molecules can be further improved, and it can be used for the direct production of light olefins from synthesis gas, which can improve the selectivity of light olefins and reduce the selectivity of methane, and achieve excellent technical effects.

[0027] In the present invention, the lanthanide metal oxide in the composite carrier can be a conventional choice in the art. According to a preferred embodiment of the present invention, the lanthanide metal oxide in the composite carrier includes at least one of cerium oxide and / or lanthanum oxide. In the present invention, cerium oxide is used as an example in the embodiment, but the present invention is not limited to this scope. By adopting the aforementioned preferred embodiment, the better dispersion of active components in the catalyst and the rapid separation of product molecules can be further improved, and it can be used for the direct production of light olefins from synthesis gas, which can improve the selectivity of light olefins and reduce the selectivity of methane, and achieve excellent technical effects.

[0028] In the present invention, the Group IIIA metal oxide in the composite carrier can be a conventional choice in the art. According to a preferred embodiment of the present invention, the Group IIIA metal oxide in the composite carrier includes at least one of gallium oxide and / or indium oxide. In the present invention, gallium oxide is used as an example in the embodiment, but the present invention is not limited to this scope. By adopting the aforementioned preferred embodiment, the better dispersion of active components in the catalyst and the rapid separation of product molecules can be further improved, and it can be used for the direct production of light olefins from synthesis gas, which can improve the selectivity of light olefins and reduce the selectivity of methane, and achieve excellent technical effects.

[0029] All composite carriers having the above characteristics can be used in the present invention, and there is no special requirement for their preparation methods. According to the present invention, a method for preparing a composite carrier is provided, and the preparation method comprises:

[0030] S1. mixing a lanthanide metal precursor, a Group IIIA metal precursor and an organic acid in a solvent to form a mixed solution A;

[0031] S2. The Group IVB metal oxide and the dispersant are added to the mixed solution A for a second mixing to form a sol;

[0032] S3. The sol is desolventized to form a gel, the gel is dried, and a first calcination is performed.

[0033] There is no special requirement for the solvent in the present invention, as long as the purpose of dissolution can be achieved, and the prior art can be referred to. In the embodiment of the present invention, the solvent in the mixed solution A is deionized water as an adaptability description, but it is not limited to the scope of the present invention, and the amount of deionized water is not limited, and can be adjusted according to actual operation.

[0034] In the present invention, the lanthanide metal precursor, the Group IIIA metal precursor, and the Group IVB metal precursor are all soluble salts corresponding to the metal elements selected in the present invention. The specific preparation method can be carried out with reference to the prior art, and the present invention will not be elaborated here.

[0035] In the present invention, the preparation method further comprises the steps of removing the solvent from the mixed solution A to form a gel and then performing a first roasting and then crushing and screening in step S3.

[0036] In the present invention, by applying Group IVB metal oxides, lanthanide metal oxides and Group IIIA metal oxides to the preparation of a composite carrier, the active components in the catalyst can be better dispersed and the product molecules can be quickly separated. The catalyst can be used for the direct production of light olefins from synthesis gas, which can improve the selectivity of light olefins and reduce the selectivity of methane, thereby achieving excellent technical effects.

[0037] According to a preferred embodiment of the present invention, there are no special requirements for the steps and conditions of crushing and screening, which can be carried out with reference to the prior art, and the present invention will not elaborate on them here.

[0038] In the present invention, in the preparation method of the composite carrier, in step S1, the weight ratio of the mixed amount of lanthanide metal oxide and group IIIA metal oxide in the mixed solution A to the organic acid can be a conventional choice in the art. According to a preferred embodiment of the present invention, the weight ratio of the mixed amount of lanthanide metal precursor in the mixed solution A in terms of lanthanide metal oxide and group IIIA metal precursor in terms of group IIIA metal oxide to the organic acid is 0.2-1.0, preferably 0.4-0.8. By adopting the aforementioned preferred embodiment, the better dispersion of active components in the catalyst and the rapid separation of product molecules can be further improved, and it can be used for the direct production of light olefins from synthesis gas, which can improve the selectivity of light olefins and reduce the selectivity of methane, and achieve excellent technical effects.

[0039] In the present invention, in the preparation method of the composite carrier, in step S1, the organic acid can be a conventional choice in the art. According to a preferred embodiment of the present invention, the organic acid includes at least one of citric acid and oxalic acid. In the present invention, citric acid is used as an example in the embodiment, but the present invention is not limited to this scope. By adopting the aforementioned preferred embodiment, the better dispersion of active components in the catalyst and the rapid separation of product molecules can be further improved, and it can be used for the direct production of light olefins from synthesis gas, which can improve the selectivity of light olefins and reduce the selectivity of methane, and achieve excellent technical effects.

[0040] In the present invention, in the preparation method of the composite carrier, in step S2, the weight ratio of the Group IVB metal oxide to the dispersant in the sol can be a conventional choice in the art. According to a preferred embodiment of the present invention, the weight ratio of the Group IVB metal oxide to the dispersant in the sol is 3-15, preferably 5-12. By adopting the aforementioned preferred embodiment, the better dispersion of the active components in the catalyst and the rapid separation of the product molecules can be further improved, and the catalyst can be used for the direct production of light olefins from synthesis gas, which can improve the selectivity of light olefins and reduce the selectivity of methane, and achieve excellent technical effects.

[0041] In the present invention, in the preparation method of the composite carrier, in step S2, the physical state of the Group IVB metal oxide has no special requirements. According to a preferred embodiment of the present invention, the Group IVB metal oxide is selected from Group IVB metal oxide powder, and the particle size of the powder is preferably 100-200 nm. By adopting the aforementioned preferred embodiment, the better dispersion of active components in the catalyst and the rapid separation of product molecules can be further improved, and the catalyst can be used for the direct production of light olefins from synthesis gas, which can improve the selectivity of light olefins and reduce the selectivity of methane, and achieve excellent technical effects.

[0042] In the method for preparing the composite carrier of the present invention, in step S2, the dispersant may be a conventional choice in the art.

[0043] According to a preferred embodiment of the present invention, the dispersant includes at least one of polyethylene glycol and methacrylic acid, preferably polyethylene glycol and / or methacrylic acid.

[0044] According to a preferred embodiment of the present invention, the dispersant is a mixture of polyethylene glycol and methacrylic acid.

[0045] According to a preferred embodiment of the present invention, the weight ratio of polyethylene glycol to methacrylic acid in the mixture is 0.2-3, preferably 0.5-2.

[0046] By adopting the aforementioned preferred implementation, the active components in the catalyst can be further dispersed better and the product molecules can be quickly separated. It can be used for the direct production of light olefins from synthesis gas, improve the selectivity of light olefins, reduce the selectivity of methane, and achieve excellent technical effects.

[0047] In the present invention, in the preparation method of the composite carrier, in steps S1-S3, the mixing conditions can be conventionally selected in the art, as long as mixed dissolution is achieved, generally mixed and dissolved at room temperature under stirring. In the embodiments of the present invention, there are no special requirements, and the operation is generally carried out at room temperature of 20-25°C.

[0048] In the preparation method of the composite carrier of the present invention, in step S3, the conditions for removing the solvent can be conventionally selected in the art, generally by evaporation. In the embodiment of the present invention, the evaporation temperature is generally 60-90° C., and the evaporation time is 6-20 hours.

[0049] In the preparation method of the composite carrier of the present invention, in step S3, the conditions for drying and first calcination of the gel can be conventionally selected in the art, and the drying temperature is generally 80-120° C., and the time is determined according to the temperature to generally achieve the purpose of removing the solvent.

[0050] According to a preferred embodiment of the present invention, the temperature for the first calcination of the gel is 250-550°C, preferably 300-500°C.

[0051] According to a preferred embodiment of the present invention, the first calcination time of the gel is 1-20 hours, preferably 2-18 hours.

[0052] By adopting the aforementioned preferred implementation, the active components in the catalyst can be further dispersed better and the product molecules can be quickly separated. It can be used for the direct production of light olefins from synthesis gas, improve the selectivity of light olefins, reduce the selectivity of methane, and achieve excellent technical effects.

[0053] According to a preferred embodiment of the present invention, in the method for preparing the composite carrier, in step S3, the composite carrier is cooled and crushed and screened after the first calcination, wherein the cooling and crushing and screening can be performed with reference to the prior art, and the present invention will not elaborate on them here.

[0054] The present invention provides an application of the composite carrier prepared by the method for preparing the composite carrier of the present invention in preparing a catalyst. According to a preferred embodiment of the present invention, the catalyst is applied in preparing an iron catalyst.

[0055] The present invention provides an iron catalyst, which comprises an active component and a carrier, wherein the active component comprises elemental iron, transition metal elements, and lanthanide metal elements; and the carrier is the composite carrier of the present invention.

[0056] In the present invention, the mass fraction of the iron catalyst can be a conventional choice in the art. According to a preferred embodiment of the present invention, the mass fraction of the iron catalyst includes 10-30wt% of elemental iron or its oxide, 4-20wt% of transition metal elements or their oxides, 1-10wt% of lanthanide metal elements or their oxides and 40-85%wt of composite carriers in terms of oxides. By adopting the aforementioned preferred embodiment, the better dispersion of active components in the catalyst and the rapid separation of product molecules can be further improved, and the reaction of directly preparing light olefins from synthesis gas can improve the selectivity of light olefins and reduce the selectivity of methane, thereby achieving excellent technical effects.

[0057] In the present invention, the elemental iron may be elemental iron and / or oxides, which is not required by the present invention and will not be elaborated herein.

[0058] In the present invention, the lanthanide metal element can be a conventional choice in the art. According to a preferred embodiment of the present invention, the lanthanide metal element includes at least one of erbium and europium. In the present invention, erbium oxide is used as an exemplary embodiment in the embodiment, but the present invention is not limited to this scope. By adopting the aforementioned preferred embodiment, the better dispersion of active components in the catalyst and the rapid separation of product molecules can be further improved, and the reaction of directly preparing light olefins from synthesis gas can improve the selectivity of light olefins and reduce the selectivity of methane, thereby achieving excellent technical effects.

[0059] In the present invention, the transition metal element can be a conventional choice in the art. According to a preferred embodiment of the present invention, the transition metal element includes at least one of chromium and vanadium. In the present invention, chromium oxide is used as an exemplary embodiment in the embodiment, but the present invention is not limited to this scope. By adopting the aforementioned preferred embodiment, the better dispersion of active components in the catalyst and the rapid separation of product molecules can be further improved, and the reaction of directly preparing light olefins from synthesis gas can improve the selectivity of light olefins and reduce the selectivity of methane, thereby achieving excellent technical effects.

[0060] In the present invention, the amount of the lanthanide metal is calculated based on the lanthanide metal in the active component, excluding the amount of lanthanide in the carrier.

[0061] In the present invention, the catalyst composition is based on the input material.

[0062] The present invention provides a method for preparing an iron catalyst, the method comprising:

[0063] (1) preparing a composite carrier according to the preparation method described in the second aspect of the present invention;

[0064] (2) Dissolving soluble salts corresponding to the iron source, transition metal source and lanthanide metal source to obtain a mixed solution B, bringing the mixed solution B into contact with the composite support for the first time to obtain a catalyst precursor, drying it, and performing a second calcination.

[0065] In the method for preparing the iron catalyst of the present invention, the conditions for the first contact can be conventionally selected in the art. According to a preferred embodiment of the present invention, the vacuum degree of the contact is 1-80 kPa.

[0066] In the present invention, in the preparation method of the composite carrier, in step (2), the second mixing conditions can be conventionally selected in the art, as long as mixed dissolution is achieved, generally mixed and dissolved at room temperature under stirring. In the embodiments of the present invention, there are no special requirements, and the operation is generally carried out at room temperature of 20-25°C.

[0067] According to a preferred embodiment of the present invention, there is no special requirement for the contact temperature, and it is generally operated at room temperature of 20-25°C, as long as mixed dissolution is achieved.

[0068] According to a preferred embodiment of the present invention, there is no special requirement for the contact time, and it is generally operated at room temperature of 20-25°C, as long as mixed dissolution is achieved.

[0069] By adopting the aforementioned preferred implementation, the active components in the catalyst can be further dispersed better and the product molecules can be quickly separated. It can be used for the direct production of light olefins from synthesis gas, improve the selectivity of light olefins, reduce the selectivity of methane, and achieve excellent technical effects.

[0070] In the present invention, a drying step is required after the catalyst precursor is impregnated. The drying conditions can be conventionally selected in the art. For example, the drying temperature is generally 80-120° C., and the time is determined according to the temperature. The present invention does not make special requirements.

[0071] In the preparation method of the iron catalyst of the present invention, the second calcination conditions of the catalyst precursor can be conventionally selected in the art. According to a preferred embodiment of the present invention, the temperature of the second calcination of the catalyst precursor is 350-700°C, preferably 400-600°C.

[0072] According to a preferred embodiment of the present invention, the catalyst precursor is subjected to a second calcination for 2-20 hours, preferably 2-12 hours.

[0073] By adopting the aforementioned preferred implementation, the active components in the catalyst can be further dispersed better and the product molecules can be quickly separated. It can be used for the direct production of light olefins from synthesis gas, improve the selectivity of light olefins, reduce the selectivity of methane, and achieve excellent technical effects.

[0074] The present invention provides application of the iron catalyst of the present invention in the reaction of preparing light olefins from synthesis gas.

[0075] The present invention provides a method for preparing light olefins from synthesis gas, the method comprising: subjecting the synthesis gas to a second contact reaction with a catalyst. According to a preferred embodiment of the present invention, the catalyst is an iron catalyst prepared by reducing the composite carrier prepared by the preparation method of the present invention.

[0076] By adopting the aforementioned preferred implementation, the active components in the catalyst can be further dispersed better and the product molecules can be quickly separated. It can be used for the direct production of light olefins from synthesis gas, improve the selectivity of light olefins, reduce the selectivity of methane, and achieve excellent technical effects.

[0077] In the method for preparing light olefins from synthesis gas of the present invention, the conditions of the second contact reaction can be conventionally selected in the art. According to a preferred embodiment of the present invention, the molar ratio of H2 to CO in the synthesis gas in the second contact reaction is 0.2-4.0, preferably 0.5-3.5.

[0078] According to a preferred embodiment of the present invention, the temperature of the second contact reaction is 250-500°C, preferably 260-460°C.

[0079] According to a preferred embodiment of the present invention, the pressure of the second contact reaction is 0.1-5.0 MPa, preferably 0.2-4.5 MPa.

[0080] According to a preferred embodiment of the present invention, the raw gas volume space velocity of the second contact reaction is 500-13000h -1 , preferably 1000-12000h -1 .

[0081] According to a preferred embodiment of the present invention, there is no special requirement for the time of the second contact, which will not be elaborated here.

[0082] By adopting the aforementioned preferred implementation, the active components in the catalyst can be further dispersed better and the product molecules can be quickly separated. It can be used for the direct production of light olefins from synthesis gas, improve the selectivity of light olefins, reduce the selectivity of methane, and achieve excellent technical effects.

[0083] In the method for preparing light olefins from synthesis gas of the present invention, the catalyst is the reduced iron catalyst of the present invention, and the reduction conditions can be conventionally selected in the art.

[0084] According to a preferred embodiment of the present invention, the reduction temperature is 350-550°C.

[0085] According to a preferred embodiment of the present invention, the reduction pressure is 0.1013-2 MPa.

[0086] According to a preferred embodiment of the present invention, the volume space velocity of the reduction is 1000-12000h -1 .

[0087] According to a preferred embodiment of the present invention, the reduction time is 2-72h.

[0088] By adopting the aforementioned preferred implementation, the active components in the catalyst can be further dispersed better and the product molecules can be quickly separated. It can be used for the direct production of light olefins from synthesis gas, improve the selectivity of light olefins, reduce the selectivity of methane, and achieve excellent technical effects.

[0089] The present invention will be described in detail below through examples.

[0090] In the present invention, the mesopores refer to pores with a pore diameter of 2-50 nm, and the macropores refer to pores with a pore diameter greater than 50 nm. The mesopore volume, macropore volume and total pore volume are measured by low-temperature liquid nitrogen adsorption BET method and calculated by BJH model.

[0091] Example 1

[0092] The composite carrier iron catalyst provided in this embodiment comprises the composite carrier described in this application and / or the composite carrier prepared by the preparation method described in this application, and the specific method is as follows:

[0093] (1) Preparation of composite carrier

[0094] Weigh 33.9 parts by weight of cerium nitrate hexahydrate (molecular formula: Ce(NO3)·6H O), gallium acetate (molecular formula: Ga(NO3)3) equivalent to 9.7 parts by weight of Ga2O3, dissolved in 100.0 parts by weight of deionized water, added with 69.3 parts by weight of citric acid (molecular formula: CHO), stirred until completely dissolved to prepare a mixed solution A; 56.4 parts by weight of titanium dioxide nanopowder (particle size 150nm) was added to the mixed solution A and stirred continuously; then 4.8 parts by weight of polyethylene glycol and 3.2 parts by weight of methacrylic acid were added as dispersants, and the powder was fully stirred to uniformly disperse to form a sol B, which was then placed in a constant temperature water solution at 80°C and stirred for 12 hours to form a gel C; the gel C was dried at 110°C in air for 24 hours, and then calcined at a calcination temperature of 420°C for 10 hours, and after cooling, it was crushed and sieved into 40-60 mesh to obtain a composite carrier D for standby use.

[0095] (2) Preparation of composite supported iron catalyst

[0096] Weigh 20.0 parts by weight of ferric nitrate nonahydrate (molecular formula: Fe(NO3)3·9H2O) equivalent to Fe2O3, 12.0 parts by weight of chromium nitrate nonahydrate (molecular formula: Cr(NO3)3·9H2O) equivalent to Cr2O3, and 6.0 parts by weight of erbium nitrate (molecular formula: Er(NO3)3) equivalent to Er2O3, and dissolve them in 40.0 parts by weight of deionized water to prepare a mixed solution E; under a vacuum degree of 80 kPa, the mixed solution E is impregnated on 62.0 parts by weight of the prepared composite carrier D to obtain a catalyst precursor F; the impregnated catalyst precursor F is dried at 110°C and then calcined at a calcination temperature of 520°C and a calcination time of 6 hours to obtain the desired composite carrier iron catalyst.

[0097] The prepared catalyst comprises the following components by weight percentage: 20% Fe2O3, 12% Cr2O3, 6% Er2O3, 35% TiO2, 21% CeO2, and 6% Ga2O3.

[0098] (3) Evaluation of catalyst

[0099] The reaction conditions are:

[0100] mm fixed bed reactor

[0101] Reaction temperature 360℃

[0102] Reaction pressure 1.6MPa

[0103] Catalyst loading: 2 mL

[0104] Raw gas volume space velocity 5000 hours-1

[0105] Raw material ratio (molar) H2 / CO=1.5 / 1.

[0106] For comparison purposes, the proportions of mesopores and macropores in the total pores of the catalyst prepared in this example and the evaluation results are listed in Table 1.

[0107] Example 2

[0108] According to the method of Example 1, the difference is that the mass formula of each component of the composite carrier includes:

[0109] 45.2 parts by weight of cerium nitrate hexahydrate of CeO2 (molecular formula: Ce(NO3)·6HO); 12.4 parts by weight of gallium acetate of Ga2O3 (molecular formula: Ga(NO3)3); 42.4 parts by weight of titanium dioxide nanopowder.

[0110] For comparison purposes, the proportions of mesopores and macropores in the total pores of the catalyst prepared in this example and the evaluation results are listed in Table 1.

[0111] Example 3

[0112] According to the method of Example 1, the difference is that the mass formula of each component of the composite carrier includes:

[0113] 22.5 parts by weight of cerium nitrate hexahydrate of CeO2 (molecular formula: Ce(NO3)·6HO); 18.1 parts by weight of gallium acetate of Ga2O3 (molecular formula: Ga(NO3)3); 59.4 parts by weight of titanium dioxide nanopowder.

[0114] For comparison purposes, the proportions of mesopores and macropores to total pores in the catalyst prepared in this example and the evaluation results are listed in Table 1.

[0115] Example 4

[0116] All conditions are the same as in Example 1, except that the mass formula of each component of the composite carrier is not within the preferred range of this application:

[0117] 55 parts by weight of cerium nitrate hexahydrate of CeO2 (molecular formula: Ce(NO3)·6H2O); 25 parts by weight of gallium acetate of Ga2O3 (molecular formula: Ga(NO3)3); 20 parts by weight of titanium dioxide nanopowder.

[0118] For comparison purposes, the proportions of mesopores and macropores in the total pores of the catalyst prepared in this example and the evaluation results are listed in Table 1.

[0119] Example 5

[0120] All conditions are the same as those in Example 1, except that the weight ratio of polyethylene glycol to methacrylic acid in the dispersant in the preparation of the composite carrier is not within the scope of the present invention.

[0121] For comparison purposes, the proportions of mesopores and macropores in the total pores of the catalyst prepared in this example and the evaluation results are listed in Table 1.

[0122] Example 6

[0123] All conditions were the same as in Example 1, except that only a single dispersant, polyethylene glycol, was added.

[0124] For comparison purposes, the composition of the catalyst of the present invention, the proportion of mesopores and macropores in the catalyst to the total pores and the evaluation results are listed in Table 1.

[0125] Example 7

[0126] All conditions were the same as in Example 1, except that no organic acid was added to S1 and no dispersant was added to S2.

[0127] For the convenience of comparison, the composition of the catalyst of this comparative example, the proportion of mesopores and macropores in the catalyst to the total pores and the evaluation results are listed in Table 1.

[0128] Table 1: Composition of catalysts of Examples and Comparative Examples, ratio of mesopores and macropores to total pores in the catalysts, and evaluation results

[0129]

[0130] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A composite carrier, characterized in that The composite carrier comprises a Group IVB metal oxide, a lanthanide metal oxide and a Group IIIA metal oxide; The volume of mesopores and macropores in the composite carrier accounts for 50-80% of the total pore volume.

2. The composite carrier according to claim 1, wherein The proportion of mesopores and macropores in the composite carrier to the total pores is 55-75%; Preferably, Based on 100 parts by weight, the composite carrier comprises 30-75 parts of Group IVB metal oxide, 20-50 parts of lanthanide metal oxide and 5-20 parts of Group IIIA metal oxide; and / or The Group IVB metal oxide in the composite carrier comprises at least one of titanium oxide and / or zirconium oxide; and / or The lanthanide metal oxide in the composite carrier comprises at least one of cerium oxide and / or lanthanum oxide; and / or The Group IIIA metal oxide in the composite carrier includes at least one of gallium oxide and / or indium oxide.

3. The method for preparing the composite carrier according to any one of claims 1 or 2, characterized in that: The preparation method comprises: S1. mixing a lanthanide metal precursor, a Group IIIA metal precursor and an organic acid in a solvent to form a mixed solution A; S2. The Group IVB metal oxide and the dispersant are added to the mixed solution A for a second mixing to form a sol; S3. The sol is desolventized to form a gel, the gel is dried, and a first calcination is performed.

4. The preparation method according to claim 3, wherein In step S1, The weight ratio of the mixed amount of the lanthanide metal precursor calculated as lanthanide metal oxide and the Group IIIA metal precursor calculated as Group IIIA metal oxide to the organic acid in the mixed solution A is 0.2-1.0, preferably 0.4-0.8; and / or The organic acid comprises at least one of citric acid and oxalic acid; and / or In step S2, The weight ratio of the Group IVB metal oxide to the dispersant in the sol is 3-15, preferably 5-12; and / or The Group IVB metal oxide is selected from Group IVB metal oxide powders, preferably with a particle size of 100-200 nm; and / or The dispersant includes at least one of polyethylene glycol and methacrylic acid, preferably includes polyethylene glycol and / or methacrylic acid; preferably, the dispersant is a mixture of polyethylene glycol and methacrylic acid, and further preferably, the weight ratio of polyethylene glycol to methacrylic acid in the mixture is 0.2-3, more preferably 0.5-2.

5. The preparation method according to any one of claims 3 or 4, wherein In step S3, The method of removing the solvent comprises: removing the solvent by evaporation at a temperature of 60-90°C for a time of 6-20 hours; and / or The first calcination conditions include: The temperature is 250-550°C, preferably 300-500°C; and / or The time is 1-20h, preferably 2-18h.

6. Use of the composite carrier according to any one of claims 1 or 2 and the method for preparing the composite carrier according to any one of claims 3 to 5 in preparing a catalyst, preferably in preparing an iron catalyst.

7. An iron catalyst, characterized in that The iron catalyst comprises an active component and a carrier, wherein the active component comprises elemental iron, a transition metal element, and a lanthanide metal element; The carrier comprises the composite carrier according to any one of claims 1 or 2; Preferably, the iron catalyst comprises: in terms of oxide, 10-30 wt% of elemental iron or its oxide, 4-20 wt% of transition metal element or its oxide, 1-10 wt% of lanthanide metal element or its oxide and 40-85 wt% of composite carrier; and / or The lanthanide metal element includes at least one of erbium and europium; and / or The transition metal element includes at least one of chromium and vanadium.

8. A method for preparing an iron catalyst, characterized in that: The method includes: (1) preparing the composite carrier according to the preparation method according to any one of claims 3 to 5; (2) Dissolving soluble salts corresponding to the iron source, transition metal source and lanthanide metal source to obtain a mixed solution B, subjecting the mixed solution B to a first contact impregnation with the composite support to obtain a catalyst precursor, drying the mixture, and performing a second calcination.

9. Use of the iron catalyst according to claim 7 or the iron catalyst obtained by the method according to claim 8 in the reaction of synthesizing light olefins from synthesis gas.

10. A method for preparing light olefins from synthesis gas, characterized in that: The method includes: subjecting the synthesis gas to a second contact reaction with a catalyst; The catalyst is the reduced iron catalyst according to claim 7 or the iron catalyst obtained by the method according to claim 8; Preferably, The conditions of the second contact reaction include: The molar ratio of H2 to CO in the synthesis gas is 0.2-4.0, preferably 0.5-3.5; and / or The temperature is 250-500°C, preferably 260-460°C; and / or The pressure is 0.1-5.0 MPa, preferably 0.2-4.5 MPa; and / or The raw gas volume space velocity is 500-13000h -1 , preferably 1000-12000h -1 .

Images