Catalyst for producing olefin from synthesis gas by one-step method, its preparation method and application

Abstract

The application discloses a catalyst for one-step production of olefins from synthesis gas and a preparation method and application thereof. The catalyst comprises zinc manganese oxide and a molecular sieve, wherein the zinc manganese oxide satisfies the following general formula: ZnMn x O (y+1) ; wherein x=1.0-3.5; y=ax, wherein a=1.0-2.0. The catalyst is used in the reaction of one-step production of olefins from synthesis gas, and has the characteristics of environmental friendliness, low cost, easy availability, simple preparation, high CO conversion rate and high low-carbon olefin yield.

Description

Technical Field

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

[0002] Low carbon olefins (C 2-4 Olefins are important organic chemical raw materials, and low-carbon olefins, represented by ethylene and propylene, are an important standard for measuring the level of a country's chemical industry. Low-carbon olefins mainly originate from petroleum cracking. With rapid economic development, the production and consumption of ethylene have increased year by year, and the development of coal-based syngas to produce low-carbon olefins has attracted widespread attention. Most direct syngas-to-low-carbon olefin production methods employ modified Fischer-Tropsch reactions, using iron / cobalt-based catalysts to achieve syngas conversion. These methods are characterized by high CO conversion rates, but the organic products are limited by the Anderson-Schulz-Flory distribution (ASF distribution), making it difficult to exceed 58% selectivity for low-carbon olefins.

[0003] In 2016, Bao Xinhe et al. reported in the literature (Science, 2016, 351, 1065-1068) a coupled catalytic system composed of metal oxides and molecular sieves, which can be used in the direct synthesis of low-carbon olefins from syngas, and can produce low-carbon olefins with high selectivity, up to 80%.

[0004] CN109939728A discloses a coupled catalyst based on metal oxides and supported molecular sieves, with the support being hierarchical porous Al2O3, SiO2, TiO2, ZrO2, CeO2, MgO, Ga2O3, etc., which can be used in the direct synthesis of low-carbon olefins from syngas, with selectivity of ethylene, propylene and butene reaching 50% to 90%, and selectivity of by-product methane less than 7%.

[0005] CN108927132A discloses a MOR structured molecular sieve modified with metal oxides and organic bases, which can be used in the reaction of carbon monoxide hydrogenation to produce ethylene with high selectivity, with an ethylene selectivity of 75% to 82% and a selectivity of less than 10% for hydrocarbon products with C4 or more.

[0006] While coupled catalyst systems of metal oxides and molecular sieves offer higher selectivity for low-carbon olefins compared to the Fischer-Tropsch reaction in the direct production of low-carbon olefins from syngas, a common drawback is the low CO conversion rate, which further affects the yield of low-carbon olefins. Therefore, developing a catalyst suitable for one-step olefin production from syngas, possessing both high selectivity for low-carbon olefins and high CO conversion, is of great significance for improving the yield of low-carbon olefins and promoting industrialization. Summary of the Invention

[0007] To address the problems of low CO conversion and low yield of low-carbon olefins in the one-step syngas-to-olefins process of existing technologies, this invention provides a catalyst for the one-step syngas-to-olefins process, its preparation method, and its application. This catalyst, when used in the one-step syngas-to-olefins process, is environmentally friendly, inexpensive and readily available, simple to prepare, and exhibits high CO conversion and high yield of low-carbon olefins.

[0008] The first aspect of this invention provides a catalyst for one-step syngas production of olefins, the catalyst comprising: zinc manganese oxide and a molecular sieve, wherein the zinc manganese oxide conforms to the following general formula: ZnMn x O (y+1) Where x = 1 to 3.5, preferably 1.5 to 3, more preferably 2 to 2.5; y = ax, where a = 1 to 2, preferably 1 to 1.5. For CO conversion and olefin yield, the effect deteriorates significantly when x is too large, it is better when x is in the range of 1.5 to 3, and the effect is best when x is in the range of 2 to 2.5.

[0009] According to the present invention, the molecular sieve includes at least one of SAPO-5, SAPO-11, SAPO-14, SAPO-17, SAPO-18, SAPO-34, SAPO-44, SAPO-47, SZZ-13, AlPO4-17, AlPO4-18, AlPO4-31, AlPO4-34 and SZZ-39.

[0010] According to the present invention, in the catalyst, zinc manganese oxide and molecular sieve exist independently of each other, such as through layered packing or mechanical mixing. The weight ratio of zinc manganese oxide to molecular sieve is 0.02 to 10, preferably 0.5 to 5.

[0011] According to the present invention, the zinc-manganese oxide in the catalyst does not include zinc-manganese oxide obtained by mechanically mixing Zn oxide and Mn oxide. Preferably, the zinc-manganese oxide is prepared by co-precipitation, preferably co-precipitation.

[0012] According to the present invention, the zinc manganese oxide in the catalyst does not contain aluminum.

[0013] A second aspect of the present invention provides a method for preparing the above-mentioned catalyst, the method comprising: mechanically mixing zinc manganese oxide and a molecular sieve to obtain the catalyst. Further, the zinc manganese oxide is prepared by a co-precipitation method.

[0014] According to the present invention, the co-precipitation method in the preparation method of zinc manganese oxide includes: reacting Zn salt and Mn salt with a precipitant in a parallel flow; the preferred reaction conditions are: reaction temperature of 50-80°C; and / or pH of 7.0-7.5.

[0015] According to the present invention, in the method for preparing the zinc-manganese oxide, after the co-current reaction is completed, the oxide is aged for 1-3 hours, filtered, washed, dried at 60-120°C for 8-12 hours, and then calcined at 400-800°C for 1-3 hours to obtain the zinc-manganese oxide. Preferably, the calcination atmosphere is an air atmosphere or a hydrogen atmosphere.

[0016] According to the present invention, the Zn salt comprises at least one selected from zinc acetate, zinc nitrate, and zinc chloride; and / or preferably, the Mn salt comprises at least one selected from manganese nitrate and manganese chloride; and / or preferably, the precipitant comprises at least one selected from ammonium carbonate, ammonium bicarbonate, ammonia, sodium hydroxide, and potassium hydroxide. According to conventional methods, the amount of precipitant added is sufficient to completely precipitate Zn and Mn.

[0017] According to the present invention, the molecular sieve is prepared using conventional methods in the art or using commercial products.

[0018] A third aspect of this invention provides the application of the above-described catalyst in a one-step synthesis gas-to-olefins process. The olefins are C2-C4 olefins.

[0019] According to the present invention, the method of application includes reacting syngas as a raw material with the above-mentioned catalyst to generate C2-C4 olefins.

[0020] According to the present invention, the equipment used in the application is a fixed-bed reactor. Preferably, the conditions for the application are: a reaction temperature of 320–480°C; and / or a reaction pressure of 1–8 MPa; and / or a syngas mass hourly space velocity of 300–8000 h⁻¹. -1 ; and / or the molar ratio of hydrogen to carbon monoxide in the synthesis gas is 0.5 to 4.

[0021] Compared with the prior art, the advantages of the present invention are as follows:

[0022] (1) In this invention, the catalyst for the one-step synthesis of olefins from syngas comprises: zinc manganese oxide and a molecular sieve, wherein the zinc manganese oxide conforms to the following general formula: ZnMn x O (y+1) Where x = 1.0–3.5; y = ax, where a = 1.0–2.0. For CO conversion and olefin yield, the effect deteriorates significantly when x is too large. Preferably, x is better when it is in the range of 1.5–3.0, and even better when it is in the range of 2.0–2.5. The catalyst of this invention is environmentally friendly and, when applied to the one-step olefin production reaction from syngas, exhibits high CO conversion and low-carbon olefin yield.

[0023] (2) In this invention, the zinc-manganese oxide is prepared by a co-precipitation method in the preparation method of the catalyst. This method is simple and easy to operate. The prepared catalyst is applied to the one-step olefin production reaction of syngas, exhibiting high CO conversion and low carbon olefin yield.

[0024] (3) In this invention, the catalyst is suitable for the one-step production of olefins from syngas. It is environmentally friendly, inexpensive and readily available, easy to prepare, has a high CO conversion rate and a high yield of low-carbon olefins. Detailed Implementation

[0025] The present invention will be further illustrated below through specific embodiments. The embodiments only provide some conditions for achieving this objective, but the scope of protection of the claims of the present invention is not limited by these embodiments.

[0026] In this invention, the actual metal atom content of the catalyst was determined by ICP, which was performed on a Varian 725-ES plasma atomic emission spectrometer. The ICP results showed that the zinc-manganese oxide in the examples contained both Zn and Mn metals. See Table 1 for the Zn / Mn (ICP molar ratio) results.

[0027] In this invention, CO conversion rate %, C 2-4 Olefin selectivity, C 2-4 Olefin yield % is a mole fraction.

[0028]

Example 1

[0029] Weigh out 0.2 mol of manganese nitrate (50 wt% manganese nitrate solution) and 0.1 mol of zinc nitrate, dissolve them in 360 mL of distilled water, and then dissolve 0.6 mol of sodium bicarbonate in 600 mL of water. Coprecipitate the two aqueous solutions in parallel streams to a pH of 7.5, age at 65 °C for 2 h, filter, dry at 100 °C for 12 h, and calcine with hydrogen at 550 °C for 2 h to obtain ZnMn₂O₃ oxide.

[0030] SAPO-34 was prepared as follows: Silica sol, hydrated alumina, and phosphoric acid were used as precursors for Si, Al, and P, respectively, and tetraethylammonium hydroxide (TEAOH) was used as a template agent. The precursors were mixed in a ratio of SiO2:Al2O3:P2O5:TEAOH:H2O = 0.6:1:1:3:80 and stirred continuously for 1 hour. The mixture was then placed in a hydrothermal reactor and crystallized at 200°C for 48 hours. After filtration and washing, the mixture was dried at 100°C for 12 hours and calcined at 550°C for 5 hours.

[0031] 1.0 g of prepared ZnMn2O3 oxide and 1.0 g of prepared SAPO-34 were granulated separately, mixed, and sieved to 20-40 mesh. The mixture was then placed into a quartz reaction tube with an inner diameter of 6 mm. A reaction mixture (n hydrogen:n carbon monoxide = 50:50) was introduced into the reaction tube, and the mixture was placed in a catalytic bed for reaction. The reaction temperature was 400℃, the reaction system pressure was 3 MPa, and the gas hourly space velocity (GHSV) was 3000 h⁻¹. -1 The synthesis of low-carbon olefins from syngas was carried out under the specified conditions. The activity evaluation results are shown in Table 1.

[0032]

Example 2

[0033] Weigh 0.2 mol of manganese nitrate (50 wt% manganese nitrate solution) and 0.1 mol of zinc nitrate and dissolve them in 360 mL of distilled water. Then dissolve 0.6 mol of sodium bicarbonate in 600 mL of water. Run the two aqueous solutions in parallel to coprecipitate the solution to pH 7.5. Aging was carried out at 65 °C for 2 h. After filtration, the solution was dried at 100 °C for 12 h and calcined in air at 550 °C for 2 h to obtain ZnMn2O5 oxide.

[0034] SAPO-34 was prepared as follows: Silica sol, hydrated alumina, and phosphoric acid were used as precursors for Si, Al, and P, respectively, and tetraethylammonium hydroxide (TEAOH) was used as a template agent. The precursors were mixed in a ratio of SiO2:Al2O3:P2O5:TEAOH:H2O = 0.6:1:1:3:80 and stirred continuously for 1 hour. The mixture was then placed in a hydrothermal reactor and crystallized at 200°C for 48 hours. After filtration and washing, the mixture was dried at 100°C for 12 hours and calcined at 550°C for 5 hours.

[0035] 1.0 g of prepared ZnMn2O5 oxide and 1.0 g of prepared SAPO-34 were granulated separately, mixed, and sieved to 20-40 mesh. The mixture was then placed into a quartz reaction tube with an inner diameter of 6 mm. A reaction mixture (n hydrogen:n carbon monoxide = 50:50) was introduced into the reaction tube, and the mixture was placed in a catalytic bed for reaction. The reaction temperature was 400℃, the reaction system pressure was 3 MPa, and the gas hourly space velocity (GHSV) was 3000 h⁻¹. -1 The synthesis of low-carbon olefins from syngas was carried out under the specified conditions. The activity evaluation results are shown in Table 1.

[0036]

Example 3

[0037] Weigh 0.3 mol of manganese nitrate (50 wt% manganese nitrate solution) and 0.1 mol of zinc nitrate and dissolve them in 760 mL of distilled water. Then dissolve 0.8 mol of sodium bicarbonate in 800 mL of water. Run the two aqueous solutions in parallel to coprecipitate the solution to pH 7.5. Aging was carried out at 65 °C for 2 h. After filtration, the solution was dried at 100 °C for 12 h and calcined with hydrogen at 550 °C for 2 h to obtain ZnMn3O4 oxide.

[0038] The preparation of SAPO-34 is the same as in [Example 1].

[0039] 1.0 g of prepared ZnMn3O4 oxide and 1.0 g of prepared SAPO-34 were granulated separately, mixed, and sieved to 20-40 mesh. The mixture was then placed into a quartz reaction tube with an inner diameter of 6 mm. A reaction mixture (n hydrogen:n carbon monoxide = 50:50) was introduced into the reaction tube, and the mixture was placed in a catalytic bed for reaction. The reaction temperature was 400℃, the reaction system pressure was 3 MPa, and the gas hourly space velocity (GHSV) was 3000 h⁻¹. -1 The synthesis of low-carbon olefins from syngas was carried out under the specified conditions. The activity evaluation results are shown in Table 1.

[0040]

Example 4

[0041] Weigh 0.3 mol of manganese nitrate (50 wt% manganese nitrate solution) and 0.1 mol of zinc nitrate and dissolve them in 760 mL of distilled water. Then dissolve 0.8 mol of sodium bicarbonate in 800 mL of water. Run the two aqueous solutions in parallel to coprecipitate the solution to pH 7.5. Aging was carried out at 65 °C for 2 h. After filtration, the solution was dried at 100 °C for 12 h and calcined in air at 550 °C for 2 h to obtain ZnMn3O7 oxide.

[0042] The preparation of SAPO-34 is the same as in [Example 1].

[0043] 1.0 g of prepared ZnMn3O7 oxide and 1.0 g of prepared SAPO-34 were granulated separately, mixed, and sieved to 20-40 mesh. The mixture was then placed into a quartz reaction tube with an inner diameter of 6 mm. A reaction mixture (n hydrogen:n carbon monoxide = 50:50) was introduced into the reaction tube, and the mixture was placed in a catalytic bed for reaction. The reaction temperature was 400℃, the reaction system pressure was 3 MPa, and the gas hourly space velocity (GHSV) was 3000 h⁻¹. -1 The synthesis of low-carbon olefins from syngas was carried out under the specified conditions. The activity evaluation results are shown in Table 1.

[0044]

Example 5

[0045] Weigh 0.25 mol of manganese nitrate (50 wt% manganese nitrate solution) and 0.1 mol of zinc nitrate, dissolve them in 660 mL of distilled water, then dissolve 0.7 mol of sodium bicarbonate in 700 mL of water. Run the two aqueous solutions concurrently to co-precipitate, achieving a pH of 7.5. Aging is carried out at 65 °C for 2 h, followed by filtration, drying at 100 °C for 12 h, and calcination under hydrogen at 550 °C for 2 h to obtain ZnMn. 2.5 O 3.5 Oxides.

[0046] The preparation of SAPO-34 is the same as in [Example 1].

[0047] 1.0g of prepared ZnMn 2.5O 3.5 The oxide and 1.0 g of prepared SAPO-34 were granulated separately, mixed, and sieved to 20-40 mesh. The mixture was then placed into a quartz reaction tube with an inner diameter of 6 mm. A reaction mixture (n hydrogen:n carbon monoxide = 50:50) was introduced into the reaction tube and placed into a catalytic bed for reaction. The reaction temperature was 400℃, the reaction system pressure was 3 MPa, and the gas hourly space velocity (GHSV) was 3000 h⁻¹. -1 The synthesis of low-carbon olefins from syngas was carried out under the specified conditions. The activity evaluation results are shown in Table 1.

[0048]

Example 6

[0049] Weigh 0.25 mol of manganese nitrate (50 wt% manganese nitrate solution) and 0.1 mol of zinc nitrate, dissolve them in 660 mL of distilled water, then dissolve 0.7 mol of sodium bicarbonate in 700 mL of water. Co-precipitate the two aqueous solutions under co-current flow. The pH is 7.5. Aging is carried out at 65 °C for 2 h, followed by filtration, drying at 100 °C for 12 h, and air calcination at 550 °C for 2 h to obtain ZnMn. 2.5 O6 oxide.

[0050] The preparation of SAPO-34 is the same as in [Example 1].

[0051] 1.0g of prepared ZnMn 2.5 O6 oxide and 1.0g of prepared SAPO-34 were granulated separately, mixed, and sieved to 20-40 mesh. The mixture was then placed into a quartz reaction tube with an inner diameter of 6mm. A reaction mixture (nhydrogen:ncarbon monoxide = 50:50) was introduced into the reaction tube and placed into a catalytic bed for reaction. The reaction temperature was 400℃, the reaction system pressure was 3MPa, and the gas hourly space velocity (GHSV) was 3000h-1. -1 The synthesis of low-carbon olefins from syngas was carried out under the specified conditions. The activity evaluation results are shown in Table 1.

[0052]

Example 7

[0053] Weigh out 0.15 mol of manganese nitrate (50 wt% manganese nitrate solution) and 0.1 mol of zinc nitrate, dissolve them in 460 mL of distilled water, then dissolve 0.5 mol of sodium bicarbonate in 500 mL of water. Let the two aqueous solutions run concurrently and co-precipitate to a pH of 7.5. Aging at 65 °C for 2 h, filtration, drying at 100 °C for 12 h, and calcination under hydrogen at 550 °C for 2 h yields ZnMn. 1.5 O 2.5 Oxides.

[0054] The preparation of SAPO-34 is the same as in [Example 1].

[0055] 1.0g of prepared ZnMn 1.5 O 2.5The oxide and 1.0 g of prepared SAPO-34 were granulated separately, mixed, and sieved to 20-40 mesh. The mixture was then placed into a quartz reaction tube with an inner diameter of 6 mm. A reaction mixture (n hydrogen:n carbon monoxide = 50:50) was introduced into the reaction tube and placed into a catalytic bed for reaction. The reaction temperature was 400℃, the reaction system pressure was 3 MPa, and the gas hourly space velocity (GHSV) was 3000 h⁻¹. -1 The synthesis of low-carbon olefins from syngas was carried out under the specified conditions. The activity evaluation results are shown in Table 1.

[0056]

Example 8

[0057] Weigh out 0.15 mol of manganese nitrate (50 wt% manganese nitrate solution) and 0.1 mol of zinc nitrate, dissolve them in 460 mL of distilled water, then dissolve 0.5 mol of sodium bicarbonate in 500 mL of water. Let the two aqueous solutions co-precipitate under parallel flow. The pH should be 7.5. Aging should be carried out at 65 °C for 2 h, filtered, dried at 100 °C for 12 h, and calcined in air at 550 °C for 2 h to obtain ZnMn. 1.5 O4 oxide.

[0058] The preparation of SAPO-34 is the same as in [Example 1].

[0059] 1.0g of prepared ZnMn 1.5 O4 oxide and 1.0g of prepared SAPO-34 were granulated separately, mixed, and sieved to 20-40 mesh. The mixture was then placed into a quartz reaction tube with an inner diameter of 6mm. A reaction mixture (nhydrogen:ncarbon monoxide = 50:50) was introduced into the reaction tube, and the mixture was placed into a catalytic bed for reaction. The reaction temperature was 400℃, the reaction system pressure was 3MPa, and the gas hourly space velocity (GHSV) was 3000h-1. -1 The synthesis of low-carbon olefins from syngas was carried out under the specified conditions. The activity evaluation results are shown in Table 1.

[0060]

Example 9

[0061] Weigh 0.1 mol of manganese nitrate (50 wt% manganese nitrate solution) and 0.1 mol of zinc nitrate and dissolve them in 360 mL of distilled water. Then dissolve 0.4 mol of sodium bicarbonate in 400 mL of water. Run the two aqueous solutions in parallel to co-precipitate the precipitate to pH 7.5. Aging was carried out at 65 °C for 2 h. After filtration, the precipitate was dried at 100 °C for 12 h and calcined with hydrogen at 550 °C for 2 h to obtain ZnMnO2 oxide. The preparation of SAPO-34 was the same as in [Example 1].

[0062] 1.0 g of prepared ZnMnO2 oxide and 1.0 g of prepared SAPO-34 were granulated separately, mixed, and sieved to 20-40 mesh. The mixture was then placed into a quartz reaction tube with an inner diameter of 6 mm. A reaction mixture (n hydrogen:n carbon monoxide = 50:50) was introduced into the reaction tube, and the mixture was placed in a catalytic bed for reaction. The reaction temperature was 400℃, the reaction system pressure was 3 MPa, and the gas hourly space velocity (GHSV) was 3000 h⁻¹. -1 The synthesis of low-carbon olefins from syngas was carried out under the specified conditions. The activity evaluation results are shown in Table 1.

[0063]

Example 10

[0064] Weigh 0.1 mol of manganese nitrate (50 wt% manganese nitrate solution) and 0.1 mol of zinc nitrate and dissolve them in 360 mL of distilled water. Then dissolve 0.4 mol of sodium bicarbonate in 400 mL of water. Run the two aqueous solutions in parallel to co-precipitate the precipitate to pH 7.5. Aging was carried out at 65 °C for 2 h. After filtration, the precipitate was dried at 100 °C for 12 h and calcined in air at 550 °C for 2 h to obtain ZnMnO3 oxide. The preparation of SAPO-34 was the same as in [Example 1].

[0065] 1.0 g of prepared ZnMnO3 oxide and 1.0 g of prepared SAPO-34 were granulated separately, mixed, and sieved to 20-40 mesh. The mixture was then placed into a quartz reaction tube with an inner diameter of 6 mm. A reaction mixture (n hydrogen:n carbon monoxide = 50:50) was introduced into the reaction tube, and the mixture was placed in a catalytic bed for reaction. The reaction temperature was 400℃, the reaction system pressure was 3 MPa, and the gas hourly space velocity (GHSV) was 3000 h⁻¹. -1 The synthesis of low-carbon olefins from syngas was carried out under the specified conditions. The activity evaluation results are shown in Table 1.

[0066]

Comparative Example 1

[0067] Weigh 0.1 mol of zinc nitrate and dissolve it in 100 mL of distilled water. Then dissolve 0.2 mol of sodium bicarbonate in 100 mL of water. Run the two aqueous solutions in parallel to co-precipitate the solution to pH 7.5. Aging is carried out at 65 °C for 2 h. After filtration, the solution is dried at 100 °C for 12 h and calcined at 550 °C under hydrogen for 2 h to obtain ZnO oxide.

[0068] The preparation of SAPO-34 is the same as in [Example 1].

[0069] 1.0 g of prepared ZnO oxide and 1.0 g of prepared SAPO-34 were granulated separately, mixed, and sieved to 20-40 mesh. The mixture was then placed into a quartz reaction tube with an inner diameter of 6 mm. A reaction mixture (n hydrogen:n carbon monoxide = 50:50) was introduced into the reaction tube, and the mixture was placed into a catalytic bed for reaction. The reaction temperature was 400℃, the reaction system pressure was 3 MPa, and the gas hourly space velocity (GHSV) was 3000 h⁻¹. -1The synthesis of low-carbon olefins from syngas was carried out under the specified conditions. The activity evaluation results are shown in Table 1.

[0070] [Comparative Example 2]

[0071] Weigh 0.1 mol of manganese nitrate (50 wt% manganese nitrate solution) and dissolve it in 60 mL of distilled water. Then dissolve 0.2 mol of sodium bicarbonate in 100 mL of water. Run the two aqueous solutions in parallel to coprecipitate the solution to pH 7.5. Aging is carried out at 65 °C for 2 h. After filtration, the solution is dried at 100 °C for 12 h and calcined at 550 °C under hydrogen for 2 h to obtain MnO oxide.

[0072] The preparation of SAPO-34 is the same as in [Example 1].

[0073] 1.0 g of prepared MnO oxide and 1.0 g of prepared SAPO-34 were granulated separately, mixed, and sieved to 20-40 mesh. The mixture was then placed into a quartz reaction tube with an inner diameter of 6 mm. A reaction mixture (n hydrogen:n carbon monoxide = 50:50) was introduced into the reaction tube and placed in a catalytic bed for reaction. The reaction temperature was 400℃, the reaction system pressure was 3 MPa, and the gas hourly space velocity (GHSV) was 3000 h⁻¹. -1 The synthesis of low-carbon olefins from syngas was carried out under the specified conditions. The activity evaluation results are shown in Table 1.

[0074] [Comparative Example 3]

[0075] ZnO oxide and MnO oxide were ground and mixed in a molar ratio (Zn / Mn = 1:2) to form a mechanically mixed sample of ZnO + Mn2O3.

[0076] The preparation of SAPO-34 is the same as in [Example 1].

[0077] 1.0 g of prepared ZnO+MnO oxide and 1.0 g of prepared SAPO-34 were granulated separately, mixed, and sieved to 20-40 mesh. The mixture was then placed into a quartz reaction tube with an inner diameter of 6 mm. A reaction mixture (n hydrogen:n carbon monoxide = 50:50) was introduced into the reaction tube, and the mixture was placed in a catalytic bed for reaction. The reaction temperature was 400℃, the reaction system pressure was 3 MPa, and the gas hourly space velocity (GHSV) was 3000 h⁻¹. -1 The synthesis of low-carbon olefins from syngas was carried out under the specified conditions. The activity evaluation results are shown in Table 1.

[0078] [Comparative Example 4]

[0079] Weigh out 0.1 mol of zinc nitrate, 0.3 mol of aluminum nitrate, and 0.1 mol of manganese nitrate (50 wt% manganese nitrate solution) and dissolve them in 1160 mL of distilled water. Then, dissolve 1.3 mol of sodium bicarbonate in 1300 mL of water. Run the two aqueous solutions concurrently to co-precipitate the solution to pH 7.5. Aging is carried out at 65 °C for 2 h, followed by filtration, drying at 100 °C for 12 h, and calcination in air at 550 °C for 2 h to obtain ZnMnAl3O4. 7.5 Oxides.

[0080] The preparation of SAPO-34 is the same as in [Example 1].

[0081] 1.0g of prepared ZnMnAl3O 7.5 The oxide and 1.0 g of prepared SAPO-34 were granulated separately, mixed, and sieved to 20-40 mesh. The mixture was then placed into a quartz reaction tube with an inner diameter of 6 mm. A reaction mixture (n hydrogen:n carbon monoxide = 50:50) was introduced into the reaction tube and placed into a catalytic bed for reaction. The reaction temperature was 400℃, the reaction system pressure was 3 MPa, and the gas hourly space velocity (GHSV) was 3000 h⁻¹. -1 The synthesis of low-carbon olefins from syngas was carried out under the specified conditions. The activity evaluation results are shown in Table 1.

[0082] [Comparative Example 5]

[0083] Weigh 0.5 mol of manganese nitrate (50 wt% manganese nitrate solution) and 0.1 mol of zinc nitrate and dissolve them in 960 mL of distilled water. Then, dissolve 1.2 mol of sodium bicarbonate in 1000 mL of water. Run the two aqueous solutions in parallel to co-precipitate the solution to pH 7.5. Aging the solution at 65 °C for 2 h, filter the solution, dry it at 100 °C for 12 h, and calcine it with hydrogen at 550 °C for 2 h to obtain ZnMn5O6 oxide.

[0084] The preparation of SAPO-34 is the same as in [Example 1].

[0085] 1.0 g of prepared ZnMn5O6 oxide and 1.0 g of prepared SAPO-34 were granulated separately, mixed, and sieved to 20-40 mesh. The mixture was then placed into a quartz reaction tube with an inner diameter of 6 mm. A reaction mixture (n hydrogen:n carbon monoxide = 50:50) was introduced into the reaction tube, and the mixture was placed in a catalytic bed for reaction. The reaction temperature was 400℃, the reaction system pressure was 3 MPa, and the gas hourly space velocity (GHSV) was 3000 h⁻¹. -1 The synthesis of low-carbon olefins from syngas was carried out under the specified conditions. The activity evaluation results are shown in Table 1.

[0086] Table 1

[0087]

[0088] Note: ZnMnAl3O 7.5The molar ratio of Zn, Mn and Al in the ICP test was 1:1.02:3.1.

[0089] The specific embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A catalyst for one-step syngas production of olefins, characterized in that, The catalyst comprises zinc manganese oxide and a molecular sieve, wherein the zinc manganese oxide conforms to the following general formula: ZnMn x O (y+1) Where x = 1.0~3.5; y = ax, where a = 1.0~2.0; the weight ratio of zinc manganese oxide to molecular sieve is 0.5~5; the zinc manganese oxide is prepared by co-precipitation method, and after co-precipitation reaction, it is aged, dried and calcined, wherein the calcination atmosphere is hydrogen atmosphere.

2. The catalyst according to claim 1, characterized in that, x = 1.5~3.0; a = 1.0~1.

5.

3. The catalyst according to claim 1, characterized in that, x = 2.0~2.5; a = 1.0~1.

5.

4. The catalyst according to claim 1, characterized in that, The molecular sieve includes at least one of SAPO-5, SAPO-11, SAPO-14, SAPO-17, SAPO-18, SAPO-34, SAPO-44, SAPO-47, SZZ-13, AlPO4-17, AlPO4-18, AlPO4-31, AlPO4-34 and SZZ-39.

5. A method for preparing the catalyst according to any one of claims 1 to 4, characterized in that, The catalyst is obtained by mechanically mixing zinc manganese oxide and molecular sieve.

6. The preparation method according to claim 5, characterized in that, The co-precipitation method includes: reacting Zn salt and Mn salt with a precipitant in a co-current flow; the co-precipitation reaction conditions are: reaction temperature 50~80℃; and / or pH 7.0~7.

5.

7. The preparation method according to claim 6, characterized in that, The Zn salt includes at least one of zinc acetate, zinc nitrate, and zinc chloride.

8. The preparation method according to claim 6, characterized in that, The Mn salt includes at least one of manganese nitrate and manganese chloride.

9. The preparation method according to claim 6, characterized in that, The precipitant includes at least one selected from ammonium carbonate, ammonium bicarbonate, ammonia, sodium hydroxide, and potassium hydroxide.

10. The application of the catalyst according to any one of claims 1-4 or the catalyst prepared by the preparation method according to any one of claims 5-9 in the one-step production of olefins from syngas.

11. The application according to claim 10, characterized in that, The conditions for the application are: a reaction temperature of 320~480℃; and / or a reaction pressure of 1~8 MPa; and / or a syngas mass hourly space velocity of 300~8000 h⁻¹. -1 ; and / or the molar ratio of hydrogen to carbon monoxide in the syngas is 0.5 to 4.

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