Synthesis gas directly making low carbon olefin catalyst, preparation method and application thereof

Abstract

The application discloses a kind of synthesis gas directly to low carbon olefin catalyst and preparation method and application, the method includes the following steps: iron source is made into solution I with manganese source, urea is added to carry out precipitation, and obtain precipitation I;Zirconium source and lanthanide source are made into solution II, urea is added to carry out precipitation, and obtain precipitation II;Precipitation I, precipitation II, binder sol and carrier sol are mixed and beaten pulp;Then, the solution containing alkali metal and component A is added, first, the pH value of slurry is adjusted to 1-6 by adding acid-base regulator, then the solution containing group VIII noble metal is added;Then, surface tension regulator is added dropwise, uniformly mixed, the above-mentioned mixed slurry is spray dried into shape, calcined, and the catalyst is obtained.The catalyst particle strength is high, the long-period operation abrasion is low, when carrying out the reaction of synthesis gas directly to low carbon olefin, the catalyst performance is excellent, the selectivity of low carbon olefin is high, and the catalyst stability is good.

Description

Technical Field

[0001] This invention belongs to the field of olefin preparation, specifically relating to a catalyst for the direct synthesis of low-carbon olefins from syngas, its preparation method, and its application. Background Technology

[0002] Low-carbon olefins generally refer to olefins with ≤4 carbon atoms and are important organic chemical raw materials. The direct production of low-carbon olefins from syngas has become a popular research direction. Iron-based catalysts are commonly used in the direct production of low-carbon olefins from syngas. The improvement of selectivity for low-carbon olefins is mainly achieved through co-catalysts, and the selection and addition of co-catalysts are key technologies for developing excellent catalysts.

[0003] Commonly used iron-based catalyst promoters are alkali metal promoters and noble metal promoters. Alkali metal promoters can increase the adsorption heat of CO on Fe-based catalysts, reduce the adsorption heat of hydrogen and hydrogenation capacity, and correspondingly increase the unsaturation of reaction products, reducing methane formation. Noble metal promoters can enhance the catalyst's adsorption and dissociation capacity for CO, thereby improving the hydrogenation activity of adsorbed CO. The direct synthesis of low-carbon olefins from syngas involves a large amount of heat release, which easily leads to catalyst coking, low activity, and low selectivity. Therefore, the reaction device must be able to quickly remove heat. Current reaction device types mainly include fixed-bed reactors, fluidized-bed reactors, and slurry-bed reactors. Fluidized-bed reactors offer easy temperature control, high heat and mass transfer efficiency, high catalyst utilization, and low operating and maintenance costs. They typically use fine microspherical catalyst particles, resulting in very low internal and external mass transfer resistance, making them an ideal catalytic reactor suitable for large-scale production. However, in a fluidized bed reactor, there is relatively intense friction and collision between catalyst particles, between catalyst particles and reactor components, and between catalyst particles and reactor walls, making catalyst particles prone to wear and breakage. Therefore, the strength and wear resistance of fluidized bed reactor catalysts are among the key indicators for evaluating the performance of fluidized bed catalysts. Summary of the Invention

[0004] This invention addresses the problems of low carbon monoxide conversion, low selectivity for low-carbon olefins, and poor catalyst stability in the direct synthesis of low-carbon olefins from syngas in existing technologies. This invention provides a catalyst for the direct synthesis of low-carbon olefins from syngas, its preparation method, and its application. The catalyst prepared by this method has the characteristics of high carbon monoxide conversion, high selectivity for low-carbon olefins, good catalyst stability, and low wear during long-term operation.

[0005] The first aspect of this invention provides a method for preparing a catalyst for the direct synthesis of low-carbon olefins from syngas, comprising the following steps:

[0006] (1) Prepare solution I by mixing iron source and manganese source, add urea to precipitate, and obtain precipitate I;

[0007] (2) Prepare solution II by mixing zirconium source and lanthanide rare earth source, add urea to precipitate, and obtain precipitate II;

[0008] (3) Mix and pulp precipitate I, precipitate II, binder sol and carrier sol;

[0009] (4) Add a solution containing alkali metal and component A to the material obtained in step (3). First, add an acid-base regulator to adjust the pH value of the slurry to 1-6, and then add a solution containing Group VIII noble metal.

[0010] (5) Add surface tension modifier to the material obtained in step (4), mix evenly, spray dry the above mixed slurry to form a mold, and calcine to obtain a catalyst.

[0011] Furthermore, the iron source, manganese source, component A source, zirconium source, and lanthanide rare earth source can be soluble compounds. The soluble iron-containing compound is at least one of ferric nitrate or ferric sulfate. The soluble compounds of manganese, component A, zirconium, and lanthanide rare earth elements are salts that can decompose into oxides, preferably nitrates.

[0012] Further, component A is selected from at least one of cobalt and alkaline earth metals, preferably an alkaline earth metal. The alkaline earth metal is selected from at least one of Mg or Ca.

[0013] Furthermore, during the catalyst preparation process, the amounts of each raw material are such that the molar ratios of iron to manganese, component A, zirconium, and lanthanides in the final catalyst are 100:10–130:1–30:5–60:0.1–10.0; the molar ratios of alkali metals to Group VIII noble metals are 0.1–10:0.01–0.50; the molar ratios of iron to alkali metals are 100:0.1–100:10.0; and the molar ratios of iron to Group VIII noble metals are 100:0.01–100:0.50.

[0014] Furthermore, in step (4), the alkali metal source and the Group VIII noble metal source used in the solution containing the alkali metal and the Group VIII noble metal can be soluble compounds. The soluble compound for the alkali metal is at least one of a nitrate, chloride, or hydroxide. The soluble compound for the Group VIII noble metal is at least one of a chloride or nitrate.

[0015] Furthermore, in step (1), the temperature of the precipitation reaction is 70-90°C and the reaction time is 10-60 minutes.

[0016] Furthermore, in step (2), the temperature of the precipitation reaction is 70-90°C and the reaction time is 10-60 minutes.

[0017] Furthermore, in step (3), precipitates I and II can be washed first and then mixed with the carrier sol for pulping.

[0018] Furthermore, in step (3), the mixing and pulping is preferably carried out in a water bath at 70–100°C.

[0019] Further, the binder sol in step (3) is selected from at least one of polysilicic acid sol or tetraethoxysilane sol, and the binder particle size in the binder sol is 1 to 10 nm.

[0020] Further, the carrier sol in step (3) is at least one of silica sol, titanium sol or alumina sol, the solid content in the carrier sol is 20% to 50%, and the solid particle size in the carrier sol is 5 to 40 nm.

[0021] Furthermore, the carrier sol added in step (3) must meet the requirement that the carrier content in the final catalyst is 20% to 50% based on the weight of the catalyst.

[0022] Further, in step (3), the mass ratio of the carrier sol to the binder sol is 2 to 15.

[0023] Furthermore, the acid-base regulator mentioned in step (4) is either ammonia or nitric acid.

[0024] Further, the surface tension modifier mentioned in step (5) is selected from at least one of ethanol, propanol, n-butanol, acetone, and butanone.

[0025] Further, preferably, in step (5), the surface tension modifier is slowly added while stirring, the stirring speed is 20-60 rpm, and the stirring time is 10-30 minutes. The amount of surface tension modifier added accounts for 0.05%-0.5% of the total weight of the material obtained in step (4).

[0026] Furthermore, the spray drying process conditions described in step (5) are not particularly limited, and those skilled in the art can reasonably select them to achieve comparable technical effects. For example, but not limited to, under the condition that the inlet temperature of the spray agent can be 200-380℃ and the outlet temperature can be 100-230℃, the spray dryer is formed into microspheres, which are then calcined to produce a catalyst. In the specific embodiments of the present invention, the spray drying conditions used are: the inlet temperature of the centrifugal sprayer is 200-380℃ and the outlet temperature is 100-250℃.

[0027] Furthermore, the roasting temperature in step (5) is preferably 400-1000℃, more preferably 450-800℃; the roasting time is preferably 0.15-10 hours, more preferably 0.5-8 hours.

[0028] Furthermore, there are no particular restrictions on the roasting atmosphere, but an oxidizing atmosphere or an inert atmosphere is preferred, and for economic reasons, an air atmosphere is more preferred.

[0029] Furthermore, in the catalyst obtained in step (5), the content of the support is 20% to 50% based on the weight of the catalyst, and the content of the active component, calculated as oxide, is 50% to 80%.

[0030] The second aspect of the present invention provides a catalyst for the direct synthesis of low-carbon olefins from syngas prepared by any of the preparation methods described in the first aspect.

[0031] Furthermore, the catalyst includes a support and an active component, wherein the active component includes a composite oxide of iron, manganese, zirconium, component A, alkali metal elements, lanthanides, and group VIII noble metal elements.

[0032] Furthermore, component A is selected from at least one of cobalt and alkaline earth metal elements, preferably an alkaline earth metal.

[0033] Furthermore, the carrier is selected from at least one of silicon dioxide, aluminum oxide, and titanium oxide.

[0034] Furthermore, the catalyst has θ-Fe3C crystal planes with a spacing of [missing information].

[0035] Furthermore, in the catalyst, the content of the support is 20% to 50% based on the weight of the catalyst, and the content of the active component, calculated as oxide, is 50% to 80%.

[0036] Further, the alkali metal is selected from at least one of the substances grouped by Li, Na, K, Rb, and Cs. The lanthanide rare earth element is selected from at least one of the substances grouped by La, Ce, Pr, and Nd. The Group VIII noble metal element is selected from at least one of the substances grouped by Pd, Pt, Ru, and Rh. The alkaline earth metal is selected from at least one of the substances grouped by Mg and Ca.

[0037] Furthermore, in the catalyst, the molar ratio of iron to manganese, component A, zirconium, and lanthanides is 100:10–130:1–30:5–60:0.1–10.0; the molar ratio of alkali metal to Group VIII noble metal is 0.1–10:0.01–0.50; the molar ratio of iron to alkali metal is 100:0.1–100:10.0; and the molar ratio of iron to Group VIII noble metal is 100:0.01–100:0.50.

[0038] Furthermore, the catalyst has a wear rate of ≤5.0% after 4 hours, preferably 4.0% to 5.0%.

[0039] A third aspect of the present invention provides an application of the above-mentioned catalyst for the direct synthesis of low-carbon olefins from syngas.

[0040] Furthermore, the application includes: syngas directly contacting a catalyst that has undergone reduction and carbonization treatment to react and generate low-carbon olefins.

[0041] Further, the reduction process includes:

[0042] (1) Using H2 / N2 gas with a volume concentration of 3% to 25%, the temperature is increased to 250 to 650°C at a rate of 3 to 25°C / minute;

[0043] (2) At a pressure of 0–5 MPa and a catalyst loading of 3000–6000 mL·h -1 ·g -1 Keep at 250-650℃ for 12-48 hours.

[0044] Further, the carbonization process includes:

[0045] (1) Using CO / N2 gas with a CO volume concentration of 40% to 100%, the temperature is increased to 250 to 550°C at a rate of 3-25°C / min;

[0046] (2) At a pressure of 0–5 MPa and a catalyst loading of 3000–6000 mL·h -1 ·g -1 Keep at 200-550℃ for 12-48 hours.

[0047] Further, the reaction conditions are as follows: reaction temperature of 200–500℃, reaction pressure (gauge pressure) of 0.5–8.0 MPa, and syngas volume hourly space velocity (VHSV), based on the amount of catalyst before reduction, of 100–8000 mL·h. -1 ·g -1 The H2 / CO molar ratio in the syngas can be 0.1 to 5.0.

[0048] Further, the preferred reaction conditions are: a reaction temperature of 220–450°C, a reaction pressure (gauge pressure) of 0.8–6.0 MPa, and a syngas volume hourly space velocity (VHSV) of 500–6000 mL·h, based on the amount of catalyst before reduction. -1 ·g -1 More preferably, it is 2000–6000 mL·h -1 ·g -1 The H2 / CO molar ratio in the syngas can be 0.5 to 3.0.

[0049] Furthermore, the low-carbon olefins refer to C2-C4 olefins, more specifically ethylene, propylene, and butene, or mixtures thereof. Butene includes butene-1, butene-2, isobutene, and butadiene.

[0050] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0051] The catalyst for the direct synthesis of low-carbon olefins from syngas provided by this invention has a special θ-Fe3C crystal plane. When applied to the reaction of direct synthesis of low-carbon olefins from syngas, the catalyst exhibits excellent performance, low wear during long-term operation, high selectivity for low-carbon olefins, and good catalyst stability.

[0052] The preparation method of the catalyst for direct synthesis of low-carbon olefins from syngas provided by the present invention optimizes the ratio and process of each component in the catalyst, and adds binders and surface tension modifiers during the catalyst preparation process. Through comprehensive coordination of each step, the catalyst particles obtained have high strength and low wear during long-term operation. When performing the reaction of direct synthesis of low-carbon olefins from syngas, the catalyst has excellent performance, high selectivity for low-carbon olefins, and good catalyst stability. Attached Figure Description

[0053] Figure 1 The image shows a transmission electron microscope (TEM) image of the catalyst prepared in Example 1 after reduction and carbonization treatment.

[0054] Figure 2 The image shown is a magnified 1x transmission electron microscope (TEM) image of region a of the catalyst prepared in Example 1 after reduction and carbonization.

[0055] Figure 3 Transmission electron microscopy (TEM) images of the catalyst prepared in Comparative Example 1 after reduction and carbonization treatment. Detailed Implementation

[0056] The technical solution of the present invention will be further illustrated below through embodiments, but the scope of protection of the present invention is not limited to the embodiments. In the present invention, wt% is a mass fraction.

[0057] The strength of the catalyst is expressed as catalyst wear. The catalyst wear test method is based on the American Society for Testing and Materials (ASTM) standard D5757. The wear was tested at 4h, 20h and 200h.

[0058] The interplanar spacing was determined by transmission electron microscopy (TEM), model Tecnai 20S-TWIN, with an accelerating voltage of 200kV.

[0059]

Example 1

[0060] (1) Take 358.0 g of ferric nitrate, add 500 g of water and stir to dissolve it under heating, add 186.4 g of 50% manganese nitrate solution, add 130.0 g of urea, heat to 90 °C under stirring to carry out precipitation reaction, and keep at 90 °C for 45 minutes; then wash and separate the precipitate to obtain precipitate I;

[0061] (2) Take 225.9 g of zirconium nitrate and 38.10 g of cerium nitrate, add 500 g of water and stir to dissolve them under heating, add 45.0 g of urea, heat to 90 °C under stirring to carry out precipitation reaction, and keep at 90 °C for 45 minutes; then wash and separate the precipitate to obtain precipitate II;

[0062] (3) Place precipitate I and precipitate II in the same container, add 1500 g of water, stir and mix, and after mixing evenly, add 125.0 g of 40% by weight of SiO2 with a diameter of 20 nm and continue stirring; then add 30.0 g of 40% (by weight) of polysilicic acid with a diameter of 10 nm, heat to 75°C and stir thoroughly to mix and slurry;

[0063] (4) Add 20g of an aqueous solution containing 5.94g KOH and 200g of an aqueous solution containing 45.80g magnesium nitrate to the material obtained in step (3). Adjust the pH of the slurry with ammonia water so that the pH of the mixed slurry is 6.0. Then add 50g of a solution containing 0.79g PdCl2 and 1.10g RuCl3.

[0064] (5) While stirring, add 25 ml of anhydrous ethanol to the material obtained in step (4) at a rate of 5 ml / min. After the addition is complete, continue stirring for 15 minutes. After thorough stirring, the prepared slurry is subjected to microsphere forming in a spray dryer using conventional methods. Finally, microspheres with an inner diameter of 89 mm and a length of 1700 mm are formed. The catalyst was calcined at 500°C for 2.0 hours in a rotary calcining furnace (mm) to obtain a catalyst with the following composition:

[0065] 80% Fe by weight 100 Mn 60.0 Mg 30.0 Zr 60.0 K 10.0 Ce 10.0 Ru 0.25 Pd 0.25 O x +20 wt% SiO2

[0066] 2. Reduction, carbonization, and evaluation of catalysts

[0067] The obtained catalyst was reduced:

[0068] The temperature was increased to 300℃ using H2 / N2 gas with a volume concentration of 5% at a rate of 5℃ / min; the conditions were: pressure 3.0 MPa, catalyst loading 100 g, and catalyst loading 4000 mL·h. -1 ·g -1 Keep at 300℃ for 15 hours.

[0069] The catalyst is then carbonized:

[0070] Using CO / N2 gas with a volume concentration of 50%, the temperature was increased to 300℃ at a rate of 5℃ / min, under conditions of 3.0 MPa pressure, 100 g catalyst loading, and 4000 mL·h catalyst loading. -1 ·g -1 Keep at 300℃ for 15 hours.

[0071] Catalyst evaluation conditions:

[0072] millimeter fluidized bed reactor

[0073] Reaction temperature 300℃

[0074] Reaction pressure 1.5 MPa

[0075] The catalyst loading amount is equivalent to 100g of catalyst before reduction.

[0076] The catalyst loading was based on the amount of catalyst before reduction, at 3000 mL·h. -1 ·g -1

[0077] Raw material ratio (moles): H2 / CO = 2 / 1.

[0078] The experimental results of the synthesis reaction of the obtained catalyst are shown in Table 1, the results after 200 hours are shown in Table 2, and the catalyst wear data are shown in Table 3.

[0079] TEM images of the catalyst after reduction and carbonization treatment are shown below. Figure 1 and Figure 2 As shown, from Figure 2 The θ-Fe3C crystal plane is clearly visible, with an intergranular spacing of [missing information].

[0080]

Example 2

[0081] (1) Take 272.7 g of ferric nitrate, add 500 g of water and stir to dissolve it under heating, add 307.8 g of 50% manganese nitrate solution, add 160.0 g of urea, heat to 90 °C under stirring to carry out precipitation reaction, and keep at 90 °C for 45 minutes; then wash and separate the precipitate to obtain precipitate I.

[0082] (2) Take 14.34 g of zirconium nitrate and 14.50 g of cerium nitrate, add 100 g of water and stir to dissolve them under heating, add 5.0 g of urea, heat to 90 °C under stirring to carry out precipitation reaction, and keep at 90 °C for 45 minutes; then wash and separate the precipitate to obtain precipitate II;

[0083] (3) Place precipitate I and precipitate II in the same container, add 1500 g of water, stir and mix, and after mixing evenly, add 312.5 g of 40% by weight SiO2 material with a diameter of 40 nm, and continue stirring; then add 150 g of 40% (by weight) polysilicic acid material with a diameter of 5 nm, heat to 75°C and stir thoroughly to mix and slurry;

[0084] (4) Add 20g of an aqueous solution containing 0.45g KOH and 100g of an aqueous solution containing 8.6g magnesium nitrate to the material obtained in step (3). Adjust the pH of the slurry with ammonia water so that the pH of the mixed slurry is 6.0. Then add 50g of a solution containing 0.01g PdCl2 and 0.01g RuCl3.

[0085] (5) While stirring, add 20 ml of propanol to the material obtained in step (4) at a rate of 5 ml / min. After the addition is complete, continue stirring for 15 minutes. After thorough stirring, the prepared slurry is subjected to microsphere forming in a spray dryer using conventional methods. Finally, microspheres with an inner diameter of 89 mm and a length of 1700 mm are formed. The catalyst was calcined at 500°C for 2.0 hours in a rotary calcining furnace (mm) to obtain a catalyst with the following composition:

[0086] 50% Fe by weight 100 Mn 130.0 Mg 5.0 Zr 5.0 K 1.0 Ce 5.0 Ru 0.005 Pd 0.005 O x +50% by weight SiO2

[0087] 2. Reduction, carbonization, and evaluation of catalysts

[0088] The obtained catalyst was reduced, activated, and then subjected to a synthesis reaction. The evaluation conditions for the reduction, carbonization, and synthesis reactions were the same as in Example 1.

[0089] The experimental results of the synthesis reaction of the obtained catalyst are shown in Table 1, the results after 200 hours are shown in Table 2, and the catalyst wear data are shown in Table 3.

[0090] The TEM image of the catalyst obtained in Example 2 is similar. Figure 1 .

[0091]

Example 3

[0092] (1) Take 475.5 g of ferric nitrate, add 800 g of water and stir to dissolve it under heating, add 41.30 g of 50% manganese nitrate solution, add 140.0 g of urea, heat to 90 °C under stirring to carry out precipitation reaction, and keep at 90 °C for 45 minutes; then wash and separate the precipitate to obtain precipitate I;

[0093] (2) Take 150.0 g of zirconium nitrate and 25.30 g of cerium nitrate, add 500 g of water and stir to dissolve them under heating, add 50 g of urea, heat to 90 °C under stirring to carry out precipitation reaction, and keep at 90 °C for 45 minutes; then wash and separate the precipitate to obtain precipitate II;

[0094] (3) Place precipitate I and precipitate II in the same container, add 1500 g of water, stir and mix, and after mixing evenly, add 218.8 g of 40% by weight of SiO2 with a diameter of 5 nm and continue stirring; then add 75.0 g of 40% (by weight) of polysilicic acid with a diameter of 10 nm, heat to 75°C and stir thoroughly to mix and slurry;

[0095] (4) Add 20g of aqueous solution containing 3.95g KOH and 200g of aqueous solution containing 44.80g magnesium nitrate to the material obtained in step (3). Adjust the pH value of the slurry with ammonia water so that the pH of the mixed slurry is 6.0. Then add 50g of solution containing 0.52g PdCl2 and 0.73g RuCl3.

[0096] (5) While stirring, add 25 ml of n-butanol to the material obtained in step (4) at a rate of 5 ml / min. After the addition is complete, continue stirring for 15 minutes. After thorough stirring, the prepared slurry is subjected to microsphere forming in a spray dryer using conventional methods. Finally, microspheres with an inner diameter of 89 mm and a length of 1700 mm are formed. The catalyst was calcined at 500°C for 2.0 hours in a rotary calcining furnace (mm) to obtain a catalyst with the following composition:

[0097] 65% Fe by weight 100 Mn 10.0 Mg 15.0 Zr 30.0 K 5.0 Ce 5.0 Ru 0.15 Pd 0.15 O x +35% by weight SiO2

[0098] 2. Reduction, carbonization, and evaluation of catalysts

[0099] The obtained catalyst was reduced, activated, and then subjected to a synthesis reaction. The evaluation conditions for the reduction, carbonization, and synthesis reactions were the same as in Example 1.

[0100] The experimental results of the synthesis reaction of the obtained catalyst are shown in Table 1, the results after 200 hours are shown in Table 2, and the catalyst wear data are shown in Table 3.

[0101] The TEM image of the catalyst obtained in Example 3 is similar. Figure 1 .

[0102]

Example 4

[0103] (1) Take 347.5 g of ferric nitrate, add 500 g of water and stir to dissolve it under heating, add 180.1 g of 50% manganese nitrate solution, add 150.0 g of urea, heat to 90 °C under stirring to carry out precipitation reaction, and keep at 90 °C for 45 minutes; then wash and separate the precipitate to obtain precipitate I;

[0104] (2) Take 109.1 g of zirconium nitrate and 18.40 g of cerium nitrate, add 500 g of water and stir to dissolve them under heating, add 50.0 g of urea, heat to 90 °C under stirring to carry out precipitation reaction, and keep at 90 °C for 45 minutes; then wash and separate the precipitate to obtain precipitate II;

[0105] (3) Place precipitate I and precipitate II in the same container, add 1500 g of water, stir and mix, and after mixing evenly, add 250.0 g of 40% by weight of SiO2 with a diameter of 10 nm and continue stirring; then add 50.0 g of 40% (by weight) of polysilicic acid with a diameter of 8 nm, heat to 75°C and stir thoroughly to mix and slurry;

[0106] (4) Add 20g of aqueous solution containing 2.87g KOH and 200g of aqueous solution containing 30.00g calcium nitrate to the material obtained in step (3). Adjust the pH value of the slurry with ammonia water so that the pH of the mixed slurry is 6.0. Then add 50g of solution containing 0.37g PdCl2 and 1.75g ​​H2PtCl6·6H2O.

[0107] (5) While stirring, add 21 ml of acetone to the material obtained in step (4) at a rate of 5 ml / min. After the addition is complete, continue stirring for 15 minutes. After thorough stirring, the prepared slurry is subjected to microsphere forming in a spray dryer using the conventional method. Finally, microspheres with an inner diameter of 89 mm and a length of 1700 mm are formed. The catalyst was calcined at 500°C for 2.0 hours in a rotary calcining furnace (mm) to obtain a catalyst with the following composition:

[0108] 60% Fe by weight 100 Mn 60.0 Ca 15.0 Zr 30.0 K .5.0 Ce 5.0 Pt 0.15 Pd 0.15 Ox +40 wt% SiO2

[0109] 2. Reduction, carbonization, and evaluation of catalysts

[0110] The obtained catalyst was reduced, activated, and then subjected to a synthesis reaction. The evaluation conditions for the reduction, carbonization, and synthesis reactions were the same as in Example 1.

[0111] The experimental results of the synthesis reaction of the obtained catalyst are shown in Table 1, the results after 200 hours are shown in Table 2, and the catalyst wear data are shown in Table 3.

[0112] The TEM image of the catalyst obtained in Example 4 is similar. Figure 1 .

[0113]

Example 5

[0114] (1) Take 317.0 g of ferric nitrate, add 500 g of water and stir to dissolve it under heating, add 165.1 g of 50% manganese nitrate solution, add 140.0 g of urea, heat to 90 °C under stirring to carry out precipitation reaction, and keep at 90 °C for 45 minutes; then wash and separate the precipitate to obtain precipitate I;

[0115] (2) Take 100.0 g of zirconium nitrate and 11.3 g of cerium nitrate, add 500 g of water and stir to dissolve them under heating, add 70.0 g of urea, heat to 90 °C under stirring to carry out precipitation reaction, and keep at 90 °C for 45 minutes; then wash and separate the precipitate to obtain precipitate II.

[0116] (3) Place precipitate I and precipitate II in the same container, add 1500 g of water, stir and mix, and after mixing evenly, add 281.3 g of 40% by weight aluminum sol material with a diameter of 30 nm of Al2O3, and continue stirring; then add 25 g of 40% (by weight) polysilicic acid material with a diameter of 8 nm, heat to 75°C and stir thoroughly to mix and slurry;

[0117] (4) Add 20g of aqueous solution containing 2.63g KOH and 200g of aqueous solution containing 27.50g calcium nitrate to the material obtained in step (3). Adjust the pH value of the slurry with ammonia water so that the pH of the mixed slurry is 6.0. Then add 50g of solution containing 1.59g H2PtCl6·6H2O and 0.49g RuCl3.

[0118] (5) While stirring, add 25 ml of butanone to the material obtained in step (4) at a rate of 5 ml / min. After the addition is complete, continue stirring for 15 minutes. After thorough stirring, the prepared slurry is subjected to microsphere forming in a spray dryer using the conventional method. Finally, microspheres with an inner diameter of 89 mm and a length of 1700 mm are formed. The catalyst was calcined at 500°C for 2.0 hours in a rotary calcining furnace (mm) to obtain a catalyst with the following composition:

[0119] 55% Fe by weight 100 Mn 60.0 Ca 15.0 Zr 30.0 K .5.0 La 5.0 Pt 0.15 Ru 0.15 O x +45% by weight Al2O3

[0120] 2. Reduction, carbonization, and evaluation of catalysts

[0121] The obtained catalyst was reduced, activated, and then subjected to a synthesis reaction. The evaluation conditions for the reduction, carbonization, and synthesis reactions were the same as in Example 1.

[0122] The experimental results of the synthesis reaction of the obtained catalyst are shown in Table 1, the results after 200 hours are shown in Table 2, and the catalyst wear data are shown in Table 3.

[0123] The TEM image of the catalyst obtained in Example 5 is similar. Figure 1 .

[0124]

Example 6

[0125] (1) Take 397.0 g of ferric nitrate, add 600 g of water and stir to dissolve it under heating, add 260.8 g of 50% manganese nitrate solution, add 180.0 g of urea, heat to 90 °C under stirring to carry out precipitation reaction, and keep at 90 °C for 45 minutes; then wash and separate the precipitate to obtain precipitate I;

[0126] (2) Take 125.3 g of zirconium nitrate, 7.10 g of lanthanum nitrate and 10.60 g of cerium nitrate, add 500 g of water and stir to dissolve under heating, add 50.0 g of urea, heat to 90 °C under stirring to carry out precipitation reaction, and keep at 90 °C for 45 minutes; then wash and separate the precipitate to obtain precipitate II;

[0127] (3) Place precipitate I and precipitate II in the same container, add 1500 g of water, stir and mix, and after mixing evenly, add 187.5 g of 40% by weight of TiO2 with a diameter of 20 nm and continue stirring; then add 100 g of 40% (by weight) of tetraethoxysilane with a diameter of 8 nm, heat to 75°C and stir thoroughly to mix and slurry;

[0128] (4) Add 20g of aqueous solution containing 3.29g KOH and 200g of aqueous solution containing 42.50g cobalt nitrate to the material obtained in step (3). Adjust the pH value of the slurry with ammonia water so that the pH of the mixed slurry is 6.0. Then add 50g of solution containing 3.32g H2PtCl6·6H2O.

[0129] (5) While stirring, add 25 ml of propanol to the material obtained in step (4) at a rate of 5 ml / min. After the addition is complete, continue stirring for 15 minutes. After thorough stirring, the prepared slurry is subjected to microsphere forming in a spray dryer using conventional methods. Finally, microspheres with an inner diameter of 89 mm and a length of 1700 mm are formed. The catalyst was calcined at 500°C for 2.0 hours in a rotary calcining furnace (mm) to obtain a catalyst with the following composition:

[0130] 70% Fe by weight 100 Mn 60.0 Co 15.0 Zr 30.0 K .5.0 La 2.5 Ce 2.5 Pt 0.25 2O x +30% by weight TiO2

[0131] 2. Reduction, carbonization, and evaluation of catalysts

[0132] The obtained catalyst was reduced, activated, and then subjected to a synthesis reaction. The evaluation conditions for the reduction, carbonization, and synthesis reactions were the same as in Example 1.

[0133] The experimental results of the synthesis reaction of the obtained catalyst are shown in Table 1, the results after 200 hours are shown in Table 2, and the catalyst wear data are shown in Table 3.

[0134] The TEM image of the catalyst obtained in Example 6 is similar. Figure 1 .

[0135]

Examples 7-14

[0136] Examples 7-14 used the catalyst obtained in Example 1. Compared with Example 1, the catalyst evaluation conditions were changed, i.e., orthogonal experimental design was used to supplement the implementation of the optimal scheme, as detailed in Table 4. The experimental results of the synthesis reaction of the obtained catalyst are shown in Table 1, the 200-hour results are shown in Table 2, and the catalyst wear data are shown in Table 3.

[0137]

Example 15

[0138] The difference compared to Example 1 is as follows:

[0139] Catalyst evaluation conditions:

[0140] millimeter fluidized bed reactor

[0141] Reaction temperature 200℃

[0142] Reaction pressure 0.6 MPa

[0143] The catalyst loading amount is equivalent to 100g of catalyst before reduction.

[0144] The catalyst loading was based on the amount of catalyst before reduction, at 1500 mL·h. -1 ·g -1

[0145] Raw material ratio (moles): H2 / CO = 0.2 / 1.

[0146] The experimental results of the synthesis reaction of the obtained catalyst are shown in Table 1, the results after 200 hours are shown in Table 2, and the catalyst wear data are shown in Table 3.

[0147]

Comparative Example 1

[0148] (1) Take 358.0 g of ferric nitrate, add 500 g of water and stir to dissolve it under heating, add 186.4 g of 50% manganese nitrate solution, add 130.0 g of urea, heat to 90 °C under stirring to carry out precipitation reaction, and keep at 90 °C for 45 minutes; then wash and separate the precipitate to obtain precipitate I;

[0149] (2) Take 225.9 g of zirconium nitrate and 38.10 g of cerium nitrate, add 500 g of water and stir to dissolve them under heating, add 45.0 g of urea, heat to 90 °C under stirring to carry out precipitation reaction, and keep at 90 °C for 45 minutes; then wash and separate the precipitate to obtain precipitate II;

[0150] (3) Place precipitate I and precipitate II in the same container, add 1500 g of water, stir and mix, and after mixing evenly, add 125.0 g of 40% by weight of SiO2 with a diameter of 20 nm, heat to 75°C and continue stirring to mix and slurry.

[0151] (4) Add 20g of an aqueous solution containing 5.94g KOH and 200g of an aqueous solution containing 45.80g magnesium nitrate to the material obtained in step (3). Adjust the pH of the slurry with ammonia water to make the pH of the mixed slurry = 6.0. Then add 50g of a solution containing 0.79g PdCl2 and 1.10g RuCl3; after adding, continue stirring for 15 minutes. After thorough stirring, the prepared slurry is subjected to microsphere forming in a spray dryer according to the conventional method. Finally, the microspheres are formed with an inner diameter of 89 mm and a length of 1700 mm. The catalyst was calcined at 500°C for 2.0 hours in a rotary calcining furnace (mm) to obtain a catalyst with the following composition:

[0152] 80% Fe by weight 100 Mn 60.0 Mg 30.0 Zr 60.0 K 10.0 Ce 10.0 Ru 0.25 Pd0.25 O x +20 wt% SiO2

[0153] The obtained catalyst was reduced, carbonized, and then synthesized. The evaluation conditions for the reduction, carbonization, and synthesis reactions were the same as in Example 1.

[0154] The experimental results of the synthesis reaction of the obtained catalyst are shown in Table 1, the results after 200 hours are shown in Table 2, and the catalyst wear data are shown in Table 3.

[0155] TEM images of the catalyst obtained in Comparative Example 1 are as follows: Figure 3 As shown in the figure, the θ-Fe3C crystal plane was not observed.

[0156] [Comparative Example 2]

[0157] Take 358.0 g of ferric nitrate, heat it, add 500 g of water and stir to dissolve it, then add 186.4 g of 50% manganese nitrate solution to obtain solution I. Take 225.9 g of zirconium nitrate and 38.10 g of cerium nitrate, heat them, add 500 g of water and stir to dissolve them to obtain solution II. Mix solution I and solution II, stir, add 175.0 g of urea, heat to 90°C with stirring to carry out the precipitation reaction, and maintain at 90°C for 45 minutes; then wash and separate the precipitate.

[0158] Add 1500 g of water to the precipitate obtained above, stir and mix thoroughly. Then add 125.0 g of 40% by weight silica sol material with a SiO2 diameter of 20 nm, heat to 75°C and continue stirring to mix and slurry. Add 20 g of aqueous solution containing 5.94 g of KOH and 200 g of aqueous solution containing 45.80 g of magnesium nitrate. Adjust the pH of the slurry with ammonia water to make the pH of the mixed slurry = 6.0. Then add 50 g of solution containing 0.79 g of PdCl2 and 1.10 g of RuCl3. After the addition is complete, continue stirring for 15 minutes.

[0159] After thorough mixing, the prepared slurry was subjected to microsphere forming in a spray dryer using conventional methods, ultimately producing particles with an inner diameter of 89 mm and a length of 1700 mm. The catalyst was calcined at 500°C for 2.0 hours in a rotary calcining furnace (mm) to obtain a catalyst with the following composition:

[0160] 80% Fe by weight 100 Mn 60.0 Mg 30.0 Zr 60.0 K 10.0 Ce 10.0 Ru 0.25 Pd 0.25 O x +20 wt% SiO2

[0161] The obtained catalyst was reduced, carbonized, and then synthesized. The evaluation conditions for the reduction, carbonization, and synthesis reactions were the same as in Example 1.

[0162] The experimental results of the synthesis reaction of the obtained catalyst are shown in Table 1, the results after 200 hours are shown in Table 2, and the catalyst wear data are shown in Table 3.

[0163] The TEM images of the catalyst obtained in Comparative Example 2 are similar. Figure 3 .

[0164] [Comparative Example 3]

[0165] Take 439.4 g of ferric nitrate, heat it, add 500 g of water and stir to dissolve it, add 130.0 g of urea, heat it to 90 °C with stirring to carry out the precipitation reaction, and keep it at 90 °C for 45 minutes; then wash and separate the precipitate to obtain precipitate I.

[0166] Take 277.3 g of zirconium nitrate and 46.80 g of cerium nitrate, add 500 g of water and stir to dissolve them under heating, add 100.0 g of urea, heat to 90 °C under stirring to carry out precipitation reaction, and keep at 90 °C for 45 minutes; then wash and separate the precipitate to obtain precipitate II.

[0167] Precipitates I and II were placed in the same container, and 1500 g of water was added. The mixture was stirred until homogeneous. Then, 125.0 g of 40% by weight SiO2 (20 nm diameter) silica sol material was added, and stirring continued. Next, 30.0 g of 40% by weight polysilicic acid (10 nm diameter) material was added, and stirring was thorough. Then, 20 g of an aqueous solution containing 7.29 g of KOH and 200 g of an aqueous solution containing 82.80 g of magnesium nitrate were added. The pH of the slurry was adjusted to 6.0 using ammonia. Then, 50 g of a solution containing 0.79 g of PdCl2 and 1.13 g of RuCl3 was added. While stirring, 25 mL of anhydrous ethanol was added at a rate of 5 mL / min. After the addition was complete, stirring continued for 15 minutes.

[0168] After thorough mixing, the prepared slurry was subjected to microsphere forming in a spray dryer using conventional methods, ultimately producing particles with an inner diameter of 89 mm and a length of 1700 mm. The catalyst was calcined at 500°C for 2.0 hours in a rotary calcining furnace (mm) to obtain a catalyst with the following composition:

[0169] 80% Fe by weight 100 Mg 30.0 Zr 60.0 K 10.0 Ce 10.0 Ru 0.25 Pd 0.25 O x +20 wt% SiO2

[0170] The obtained catalyst was reduced, carbonized, and then synthesized. The evaluation conditions for the reduction, carbonization, and synthesis reactions were the same as in Example 1.

[0171] The experimental results of the synthesis reaction of the obtained catalyst are shown in Table 1, the results after 200 hours are shown in Table 2, and the catalyst wear data are shown in Table 3.

[0172] The TEM images of the catalyst obtained in Comparative Example 3 are similar. Figure 3 .

[0173] [Comparative Example 4]

[0174] (1) Take 179.1 g of ferric nitrate, add 500 g of water and stir to dissolve it under heating, add 93.2 g of 50% manganese nitrate solution, add 130.0 g of urea, heat to 90 °C under stirring to carry out precipitation reaction, and keep at 90 °C for 45 minutes; then wash and separate the precipitate to obtain precipitate I;

[0175] (2) Take 113.0 g of zirconium nitrate and 19.10 g of cerium nitrate, add 500 g of water and stir to dissolve them under heating, add 45.0 g of urea, heat to 90 °C under stirring to carry out precipitation reaction, and keep at 90 °C for 45 minutes; then wash and separate the precipitate to obtain precipitate II;

[0176] (3) Place precipitate I and precipitate II in the same container, add 1500 g of water, stir and mix, and after mixing evenly, add 375.0 g of 40% by weight of SiO2 with a diameter of 20 nm and continue stirring; then add 30.0 g of 40% (by weight) of polysilicic acid with a diameter of 10 nm, heat to 75°C and stir thoroughly to mix and slurry;

[0177] (4) Add 20g of an aqueous solution containing 2.97g KOH and 200g of an aqueous solution containing 33.80g magnesium nitrate to the material obtained in step (3). Adjust the pH of the slurry with ammonia water so that the pH of the mixed slurry is 6.0. Then add 50g of a solution containing 0.32g PdCl2 and 0.46g RuCl3.

[0178] (5) While stirring, add 25 ml of anhydrous ethanol to the material obtained in step (4) at a rate of 5 ml / min. After the addition is complete, continue stirring for 15 minutes. After thorough stirring, the prepared slurry is subjected to microsphere forming in a spray dryer using conventional methods. Finally, microspheres with an inner diameter of 89 mm and a length of 1700 mm are formed. The catalyst was calcined at 500°C for 2.0 hours in a rotary calcining furnace (mm) to obtain a catalyst with the following composition:

[0179] 40% Fe by weight 100 Mn 60.0 Mg 30.0 Zr60.0 K 10.0 Ce 10.0 Ru 0.25 Pd 0.25 O x +60 wt% SiO2

[0180] The obtained catalyst was reduced, carbonized, and then synthesized. The evaluation conditions for the reduction, carbonization, and synthesis reactions were the same as in Example 1.

[0181] The experimental results of the synthesis reaction of the obtained catalyst are shown in Table 1, the results after 200 hours are shown in Table 2, and the catalyst wear data are shown in Table 3.

[0182] The TEM images of the catalyst obtained in Comparative Example 4 are similar. Figure 3 .

[0183] Table 1 Catalyst activity at the initial stage of reaction

[0184]

[0185]

[0186] Table 2 Catalyst activity after 200 h of reaction.

[0187]

[0188] Note: C2 0 ~C4 0 It represents ethane, propane, and butane.

[0189] Table 3. Catalyst wear at different time points in the examples and comparative examples.

[0190]

[0191] Table 4. Changes in reaction conditions in Examples 7-14

[0192]

[0193]

[0194] The embodiments described above are merely detailed descriptions of the technical solutions of the present invention, but the present invention is not limited to the above embodiments, that is, the present invention does not depend on the steps described in the above embodiments to be implemented. In summary, any improvements made to the present invention by those skilled in the art, including the substitution of the raw materials and additives described in the present invention, the selection of specific implementation methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a catalyst for the direct synthesis of low-carbon olefins from syngas, characterized in that, The catalyst has θ-Fe3C crystal planes with a plane spacing of 2.7~3.7 Å. The catalyst precursor includes a support and an active component, wherein the active component includes a composite oxide of iron, manganese, zirconium, component A, alkali metal elements, lanthanides, and group VIII noble metal elements, and component A is selected from at least one of cobalt and alkaline earth metal elements. In the catalyst precursor, the molar ratio of iron to manganese, component A, zirconium, and lanthanides is 100:10~130:1~30:5~60:0.1~10.

0. The molar ratio of the metal element to the Group VIII noble metal element is 0.1~10:0.01~0.50, the molar ratio of iron to the alkali metal element is 100:0.1~100:10.0, and the molar ratio of iron to the Group VIII noble metal element is 100:0.01~100:0.50; in the catalyst precursor, based on the weight of the catalyst precursor, the content of the support is 20%~50%, and the content of the active component, calculated as oxide, is 50%~80%; the preparation method of the catalyst includes the following steps: (1) Prepare solution I by mixing iron source and manganese source, add urea to precipitate, and obtain precipitate I; (2) Prepare solution II by mixing zirconium source and lanthanide rare earth source, add urea to precipitate, and obtain precipitate II; (3) Mix and pulp precipitate I, precipitate II, binder sol and carrier sol; (4) Add a solution containing alkali metal and component A to the material obtained in step (3). First, add an acid-base regulator to adjust the pH value of the slurry to 1~6, and then add a solution containing Group VIII noble metal. (5) Add surface tension modifier to the material obtained in step (4), mix evenly, spray dry the above mixed slurry into shape, and calcine to obtain catalyst precursor; (6) The catalyst precursor obtained in step (5) is subjected to reduction and carbonization treatment to obtain the catalyst; The adhesive sol mentioned in step (3) is selected from at least one of polysilicic acid sol or tetraethoxysilane sol; The surface tension modifier mentioned in step (5) is selected from at least one of ethanol, propanol, n-butanol, acetone, and butanone.

2. The preparation method according to claim 1, characterized in that, The precipitation reaction in step (1) is carried out at a temperature of 70~90℃ and a reaction time of 10~60 minutes; and / or, the precipitation reaction in step (2) is carried out at a temperature of 70~90℃ and a reaction time of 10~60 minutes; and / or, the mixing and pulping in step (3) is carried out in a water bath at 70~100℃.

3. The preparation method according to claim 1, characterized in that, The carrier sol is at least one of silica sol, titanium sol or alumina sol, and the solid content of the carrier sol is 20% to 50%; and / or, in step (3), the mass ratio of the carrier sol to the binder sol is 2 to 15; and / or, in step (4), the acid-base regulator is one of ammonia or nitric acid.

4. The preparation method according to claim 1, characterized in that, Component A is an alkaline earth metal.

5. The preparation method according to claim 3, characterized in that, The binder sol has a binder particle size of 1~10nm; and / or, the carrier sol has a solid particle size of 5~40nm.

6. The preparation method according to claim 1, characterized in that, In step (5), a surface tension modifier is added while stirring. The stirring speed is 20-60 rpm and the stirring time is 10-30 minutes. And / or, the calcination temperature in step (5) is 400-1000℃ and the calcination time is 0.15-10 hours.

7. The preparation method according to claim 6, characterized in that, The roasting temperature in step (5) is 450~800℃; the roasting time is 0.5~8 hours.

8. The preparation method according to claim 1, characterized in that, In step (6), the reduction process includes: (1) Using H2 / N2 gas with a volume concentration of 3%~25%, the temperature is increased to 250~650℃ at a rate of 3~25℃ / min; (2) At a pressure of 0~5MPa and a catalyst precursor loading of 3000~6000mL·h -1 ·g -1 Maintain at 250-650℃ for 12-48 hours; And / or, the carbonization process includes: (1) Using CO / N2 gas with a CO volume concentration of 40%~100%, the temperature is increased to 250~550℃ at a rate of 3~25℃ / min; (2) At a pressure of 0~5MPa and a catalyst precursor loading of 3000~6000mL·h -1 ·g -1 Keep at 200~550℃ for 12~48 hours.

9. The catalyst for direct synthesis of low-carbon olefins from syngas prepared by the preparation method according to any one of claims 1-8.

10. The catalyst for direct synthesis of low-carbon olefins from syngas according to claim 9, characterized in that, In the catalyst precursor, the alkali metal is selected from at least one of the group consisting of Li, Na, K, Rb and Cs; the lanthanide rare earth element is selected from at least one of the group consisting of La, Ce, Pr and Nd; the group VIII noble metal element is selected from at least one of the group consisting of Pd, Pt, Ru and Rh; and the alkaline earth metal is selected from at least one of the group consisting of Mg and Ca.

11. The application of the catalyst for direct synthesis of low-carbon olefins from syngas according to any one of claims 9-10 in the reaction of direct synthesis of low-carbon olefins from syngas.

12. The application according to claim 11, characterized in that, The reaction temperature is 200–500 °C; and / or, the reaction pressure is 0.5–8.0 MPa; and / or, the volume hourly space velocity of the syngas, based on the amount of catalyst precursor, is 100–8000 mL·h. -1 ·g -1 ; and / or, the H2 / CO molar ratio in the syngas is 0.1~5.

0.

13. The application according to claim 12, characterized in that, The reaction temperature is 220–450 °C; and / or, the reaction pressure is 0.8–6.0 MPa; and / or, the volume hourly space velocity of the syngas, based on the amount of catalyst precursor, is 500–6000 mL·h. -1 ·g -1 ; and / or, the H2 / CO molar ratio in the syngas is 0.5~3.

0.

14. The application according to claim 13, characterized in that, The volume hourly space velocity of the synthesis gas, based on the amount of catalyst precursor, is 2000~6000 mL·h. -1 ·g -1 .

Images