A catalyst for synthesizing low-carbon olefins from synthesis gas, a preparation method thereof and applications thereof

Abstract

The application discloses a catalyst for synthesizing low-carbon olefins from synthesis gas and a preparation method and application thereof. The catalyst comprises an active component, and the active component comprises iron elements, manganese elements, germanium elements, zirconium elements, D elements and alkali metal elements. The D elements are at least one selected from zinc, cobalt and nickel. The catalyst is an iron-based catalyst, which can solve the problem of low selectivity of low-carbon olefins in the prior art, and provides a method for directly synthesizing low-carbon olefins from synthesis gas. The method has the characteristics of low conversion rate of a reactant carbon monoxide and high selectivity of target products low-carbon olefins.

Description

Technical Field

[0001] This invention belongs to the technical field of catalysts, and particularly relates to catalysts for the synthesis of low-carbon olefins from syngas, their preparation methods, and applications. Background Technology

[0002] Low-carbon olefins (olefins with ≤4 carbon atoms), represented by ethylene and propylene, are basic raw materials for the chemical industry. Currently, the main raw materials for low-carbon olefins worldwide are petroleum hydrocarbons, with naphtha accounting for the majority, along with alkanes, hydrotreated diesel, and some heavy oils. Domestically and internationally, low-carbon olefins are mostly produced using natural gas or light petroleum distillates as feedstocks, employing steam cracking processes in ethylene complexes. Steam cracking is a high-energy-consuming process in petrochemicals and is entirely dependent on non-renewable petroleum resources. With the increasing scarcity of petroleum resources, there is an urgent need to find alternative resources. Therefore, research on using other resources to replace petroleum in the production of olefins has gained attention, and some of the world's leading oil companies and research institutions have conducted research and development in this area. Direct production of low-carbon olefins from syngas is currently one of the research hotspots. This involves converting syngas into hydrocarbons through a catalyst, specifically through the catalytic hydrogenation of CO on a metal catalyst, producing a mixture mainly composed of straight-chain alkanes and olefins.

[0003] Iron-based catalysts are commonly used for the direct synthesis of low-carbon olefins from syngas due to their superior performance and economic efficiency. The addition of supports and promoters during the preparation process can further improve the stability and selectivity of iron-based catalysts. The prepared catalysts require further activation before use to enhance their performance. However, with the maturation of syngas-to-low-carbon olefins technology, the preparation of iron-based catalysts also faces increasing challenges.

[0004] The successful preparation of iron-based catalysts is a key step in achieving good application results in the synthesis of low-carbon olefins from syngas. The catalytic effects of iron-based catalysts prepared by different methods also vary, and the selection of promoters and supports has an important impact on the various properties of the catalysts.

[0005] However, existing iron-based catalysts still suffer from low conversion rates of carbon monoxide and low selectivity for low-carbon olefins as the target product. Summary of the Invention

[0006] To overcome the problems existing in the prior art, this invention provides a catalyst for the production of low-carbon olefins from syngas and its preparation method. The catalyst is an iron-based catalyst, which can solve the problem of low selectivity for low-carbon olefins in the prior art. The method for the direct production of low-carbon olefins from syngas provided by this invention has the characteristics of high conversion rate of carbon monoxide as a reactant and high selectivity for low-carbon olefins as the target product.

[0007] One objective of this invention is to provide a catalyst for the synthesis of low-carbon olefins from syngas, comprising an active component including iron, manganese, germanium, zirconium, D, and an alkali metal element, wherein the D element is selected from at least one of zinc, cobalt, and nickel.

[0008] Preferably, each element in the active component exists in oxide form. More preferably, the catalyst includes an active component composed of iron, manganese, germanium, zirconium, dynamite, and alkali metal elements.

[0009] In a preferred embodiment, the alkali metal is selected from at least one of lithium, sodium, and potassium.

[0010] In a preferred embodiment, the molar ratio of manganese to iron in the catalyst is (30-130):100, preferably (40-120):100.

[0011] For example, in the catalyst, the molar ratio of manganese to iron is 30:100, 50:100, 70:100, 90:100, 110:100 or 130:100.

[0012] In a preferred embodiment, the molar ratio of germanium to iron in the catalyst is (4-30):100, preferably (4-15):100.

[0013] For example, in the catalyst, the molar ratio of germanium to iron is 4:100, 5:100, 10:100, 15:100, 20:100, 25:100 or 30:100.

[0014] In a preferred embodiment, the molar ratio of zirconium to iron in the catalyst is (10-60):100, preferably (15-40):100.

[0015] For example, in the catalyst, the molar ratio of zirconium to iron is 10:100, 20:100, 30:100, 40:100, 50:100 or 60:100.

[0016] In a preferred embodiment, the molar ratio of D to iron in the catalyst is (5-30):100, preferably (10-25):100.

[0017] For example, in the catalyst, the molar ratio of D to iron is 5:100, 10:100, 15:100, 20:100, 25:100 or 30:100.

[0018] In a preferred embodiment, the molar ratio of alkali metal to iron in the catalyst is (1-10):100, preferably (2-8):100.

[0019] For example, in the catalyst, the molar ratio of alkali metal to iron is 1:100, 2:100, 4:100, 6:100, 8:100 or 10:100.

[0020] In a preferred embodiment, the active component comprises a composition of the following formula:

[0021] Fe 100 Mn a Ge b Zr c D d E e O x Wherein: element D is selected from at least one of zinc, cobalt, and nickel; element E represents an alkali metal element; the value of a ranges from 30 to 130, preferably from 40 to 120; the value of b ranges from 4 to 30, preferably from 4 to 15; the value of c ranges from 10 to 60, preferably from 15 to 40; the value of d ranges from 5 to 30, preferably from 10 to 25; the value of e ranges from 1 to 10, preferably from 2 to 8; and x is the total number of oxygen atoms required to satisfy the oxidation states of each element in the catalyst.

[0022] In a preferred embodiment, the XPS spectrum of the catalyst has a characteristic peak of 707.5 ± 1.0 eV, which is attributed to iron.

[0023] The presence of this characteristic peak indicates that the iron atoms are in a special chemical environment. This iron in a specific chemical environment serves as the main component of the catalyst in this invention. It has a good effect on the adsorption, cracking, intermediate product generation, target product generation, and desorption of reactants in the synthesis of low-carbon olefins from syngas. As a result, the catalyst performance, namely the carbon monoxide conversion rate and the low-carbon olefin selectivity, is very high.

[0024] In a further preferred embodiment, the XPS spectrum of the catalyst further exhibits a characteristic peak of 721 eV ± 1.0 eV, which is attributed to iron.

[0025] In a preferred embodiment, the catalyst further contains a binder.

[0026] In a further preferred embodiment, the adhesive is selected from at least one of silicon dioxide, aluminum oxide, and titanium dioxide.

[0027] In a further preferred embodiment, the binder content is 2 to 15 wt% of 100 wt% of the catalyst, for example, 2 wt%, 5 wt%, 8 wt%, 10 wt%, 12 wt% or 15 wt%.

[0028] The catalyst described in this invention, under the synergistic effect of iron, manganese, germanium, zirconium, D, and alkali metal elements (preferably all of which are indispensable), has the characteristics of high conversion rate of carbon monoxide reactant and high selectivity of low-carbon olefins as target product.

[0029] The second objective of this invention is to provide a method for preparing a catalyst for the synthesis of low-carbon olefins from syngas, preferably for preparing the catalyst described in the first objective of this invention. The preparation method includes: precipitating and aging a solution containing an iron precursor and a solution containing a zirconium precursor, then mixing the mixture with raw materials including a solution containing a manganese precursor, a solution containing a germanium precursor, a solution containing a D element precursor, and a solution containing an alkali metal element precursor, and then drying (e.g., spray drying) and calcining to obtain the catalyst.

[0030] In a preferred embodiment, the preparation method includes:

[0031] (1) Mix the solution containing the iron precursor and the solution containing the zirconium precursor to obtain dispersion I;

[0032] (2) The precipitant is mixed with the dispersion I, and after precipitation and aging, dispersion II is obtained;

[0033] (3) Separate the solid phase from the dispersion II, wash it, and obtain the precipitate;

[0034] (4) The precipitate is mixed with a solution containing a manganese precursor, a solution containing a germanium precursor, a solution containing a D element precursor, and a binder. The pH is adjusted, and then a solution containing an alkali metal element precursor is added. The mixture is then dried (e.g., spray dried) and calcined to obtain the catalyst.

[0035] In a preferred embodiment, the iron precursor is selected from at least one of iron nitrates, iron carbonates, and iron oxalates, preferably from iron nitrates.

[0036] In a preferred embodiment, the zirconium precursor is selected from at least one of zirconium nitrate, zirconium carbonate, and zirconium oxalate, preferably from zirconium nitrate.

[0037] In a preferred embodiment, the manganese precursor is selected from at least one of manganese nitrate, manganese carbonate, and manganese oxalate, preferably manganese nitrate.

[0038] In a preferred embodiment, the germanium precursor is selected from at least one of germanium nitrate, germanium carbonate, and germanium oxalate, preferably from germanium nitrate.

[0039] In a preferred embodiment, the D element precursor is selected from at least one of the following: nitrates of D element, carbonates of D element, and oxalates of D element, preferably nitrates of D element.

[0040] In a preferred embodiment, the alkali metal precursor is selected from at least one of alkali metal nitrates, alkali metal carbonates, and alkali metal hydroxides, preferably from alkali metal hydroxides.

[0041] In this invention, the “solution” mentioned in steps (1) and (4) preferably refers to an aqueous solution.

[0042] In a preferred embodiment, the molar ratio of iron in the iron precursor to zirconium in the zirconium precursor is 100:(10-60), preferably 100:(15-40); and / or, the molar ratio of iron in the iron precursor to manganese in the manganese precursor is 100:(30-130), preferably 100:(40-120); and / or, the molar ratio of iron in the iron precursor to germanium in the germanium precursor is... The molar ratio is 100:(4-30), preferably 100:(4-15); and / or, the molar ratio of iron in the iron precursor to D element in the D element precursor is 100:(5-30), preferably 100:(10-25); and / or, the molar ratio of iron in the iron precursor to alkali metal element in the alkali metal element precursor is 100:(1-10), preferably 100:(2-8).

[0043] In a preferred embodiment, the precipitant in step (2) is selected from alkaline precipitants, preferably from at least one of ammonia, urea, and organic amines; more preferably, the organic amine is selected from at least one of methylamine, ethylamine, and ethylenediamine.

[0044] In a further preferred embodiment, in step (2), the molar amount of the precipitant is greater than or equal to the sum of the molar amounts of iron in the iron precursor, zirconium in the zirconium precursor, manganese in the manganese precursor, germanium in the germanium precursor, D in the D precursor, and alkali in the alkali metal precursor.

[0045] Preferably, the ratio of the precipitant to the sum of the molar amounts of iron in the iron precursor, zirconium in the zirconium precursor, manganese in the manganese precursor, germanium in the germanium precursor, D in the D precursor, and alkali in the alkali metal precursor is 1:(1-2), more preferably 1:(1-1.5), for example 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, or 1:2.

[0046] In a preferred embodiment, in step (2), the precipitation is carried out at room temperature to 95°C, preferably at 50°C to 90°C; more preferably, the temperature is maintained for 0.2 to 4 hours, preferably 0.5 to 3 hours.

[0047] For example, in step (2), the precipitation is carried out at 50°C, 60°C, 70°C, 80°C, 90°C or 95°C; and kept at the temperature for 0.2h, 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h or 4h.

[0048] In a preferred embodiment, in step (2), the aging is carried out at room temperature, preferably for 10 to 30 hours, such as 10 hours, 12 hours, 15 hours, 18 hours, 20 hours, 22 hours, 25 hours, 28 hours or 30 hours.

[0049] In a preferred embodiment, in step (3), water is used for washing.

[0050] In a preferred embodiment, in step (4), the adhesive is selected from at least one of silicon dioxide, aluminum oxide, and titanium dioxide.

[0051] In a further preferred embodiment, based on a total weight of 100 wt% of iron in the iron precursor, zirconium in the zirconium precursor, manganese in the manganese precursor, germanium in the germanium precursor, D in the D precursor, and alkali metal in the alkali metal precursor, the amount of binder is 3 to 25 wt%, for example, 3 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, or 25 wt%.

[0052] In a preferred embodiment, in step (4), the pH is adjusted to 1 to 6, for example, 1, 2, 3, 4, 5 or 6.

[0053] In a preferred embodiment, in step (4), the roasting temperature is 300-800°C and the time is 2-12 hours.

[0054] In a further preferred embodiment, in step (4), the calcination temperature is 400-700°C and the time is 3-10 hours.

[0055] In a preferred embodiment, the catalyst is first subjected to reduction and carbonization treatment before use.

[0056] In a preferred embodiment, the reduction treatment conditions include: a pressure of 0–2 MPa; and / or a catalyst loading of 3000–6000 mL·h. -1 ·g -1 ; and / or, the temperature is 200–550°C; and / or, the time is 12–48 hours; and / or, the heating rate is 1–15°C / minute.

[0057] For example, pressures of 0 MPa, 0.2 MPa, 0.5 MPa, 0.8 MPa, 1 MPa, 1.2 MPa, 1.5 MPa, 1.8 MPa, or 2 MPa; and / or catalyst loadings of 3000, 3500, 4000, 4500, 5000, 5500, or 6000 mL·h. -1 ·g -1 ; and / or, the temperature is 200°C, 250°C, 300°C, 350°C, 400°C, 450°C, 500°C, or 550°C; and / or, the time is 12, 15, 20, 25, 30, 35, 40, 45, or 48 hours; and / or, the heating rate is 1, 2, 5, 8, 10, 12, or 15°C / minute.

[0058] In a further preferred embodiment, the atmosphere of the reduction treatment is a mixture of H2 and N2; preferably, based on the total volume of the mixture, the volume concentration of H2 is 1% to 20% and the volume concentration of N2 is 80% to 99%.

[0059] For example, based on the total volume of the gas mixture, the volume concentration of H2 is 1%, 2%, 5%, 8%, 10%, 12%, 15%, 18%, or 20%, and the volume concentration of N2 is 82%, 85%, 88%, 90%, 92%, 95%, 98%, or 99%.

[0060] In a preferred embodiment, the carbonization treatment conditions include: a pressure of 0–2 MPa; and / or a catalyst loading of 3000–6000 mL·h. -1 ·g -1 ; and / or, the temperature is 200–550°C; and / or, the time is 12–48 hours; and / or, the heating rate is 3–20°C / minute.

[0061] For example, the carbonization treatment conditions include: a pressure of 0, 0.2, 0.5, 0.8, 1, 1.2, 1.5, 1.8, or 2 MPa; and / or a catalyst loading of 3000, 3500, 4000, 4500, 5000, 5500, or 6000 mL·h. -1 ·g -1 ; and / or, the temperature is 200°C, 250°C, 300°C, 350°C, 400°C, 450°C, 500°C, or 550°C; and / or, the time is 12, 15, 20, 25, 30, 35, 40, 45, or 48 hours; and / or, the heating rate is 3, 5, 8, 10, 12, 15, 18, or 20°C / minute.

[0062] In a further preferred embodiment, the atmosphere for the carbonization treatment is a mixture of CO and / or C2H4 and N2; preferably, based on the total volume of the mixture (100%), the total volume concentration of CO and / or C2H4 is 10% to 60% (e.g., 10%, 20%, 30%, 40%, 50%, or 60%), and the volume concentration of N2 is 40% to 90% (e.g., 40%, 50%, 60%, 70%, 80%, or 90%); more preferably, based on the total volume concentration of CO and C2H4 (100%), CO is 0% to 100%, preferably 20% to 80% (e.g., 20%, 40%, 60%, or 80%), and C2H4 is 0% to 100%, preferably 20% to 80% (e.g., 20%, 40%, 60%, or 80%).

[0063] A third objective of this invention is to provide a catalyst obtained using the preparation method described in the second objective of this invention.

[0064] The fourth objective of this invention is to provide the application of the catalyst described in the first objective of this invention or the catalyst obtained by the preparation method described in the second objective of this invention in the direct preparation of low-carbon olefins from syngas.

[0065] The fifth objective of this invention is to provide a method for the direct preparation of low-carbon olefins from syngas, comprising: reacting H2 with CO in the presence of a catalyst, wherein the catalyst is selected from the catalyst described in the first objective of this invention or the catalyst obtained by the preparation method described in the second objective of this invention.

[0066] In a preferred embodiment, the catalyst is subjected to the reduction treatment and the carbonization treatment prior to the contact.

[0067] In a preferred embodiment, the reaction temperature is 200–600°C; and / or the reaction pressure is 0.5–10 MPa; and / or, based on the amount of catalyst before reduction, the volume hourly space velocity of the syngas is 100–8000 mL·h.-1 ·g -1 ; and / or, the H2 / CO molar ratio in the synthesis gas is 0.1 to 5.

[0068] For example, the reaction temperature is 200°C, 300°C, 400°C, 500°C, or 600°C; and / or, the reaction pressure is 0.5, 0.6, 0.7, 0.8, 0.9, or 10 MPa; and / or, based on the amount of catalyst before reduction, the syngas volume hourly space velocity is 100, 200, 500, 800, 1000, 2000, 4000, 6000, or 8000 mL·h. -1 ·g -1 ; and / or, the H2 / CO molar ratio in the synthesis gas is 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5 or 5.

[0069] In a preferred embodiment, the low-carbon olefin is a C2-C4 olefin.

[0070] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values; these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. In the following, various technical solutions can, in principle, be combined with each other to obtain new technical solutions, which should also be considered as specifically disclosed herein.

[0071] Compared with the prior art, the present invention has the following beneficial effects: The microspherical fluidized bed catalyst provided by the present invention, by utilizing the interaction between various promoters, especially Ge, and the catalyst main agent Fe, can increase the carbon monoxide conversion rate and increase the C2 content in the low-carbon olefin product during the direct production of low-carbon olefins from fluidized bed syngas. ＝ +C3 ＝ :C4 ＝ The ratio of ) is beneficial to the production of more valuable ethylene and propylene. Attached Figure Description

[0072] Figure 1 The XPS spectrum of the catalyst obtained in Example 1 is shown. Detailed Implementation

[0073] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0074] It should also be noted that the various specific technical features described in the following embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the various possible combinations will not be described separately in this invention.

[0075] Furthermore, various embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention. The resulting technical solutions are part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0076] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0077] The catalyst composition in the examples is a theoretical value inferred from the amount of raw materials used.

[0078]

Example 1

[0079] (1) Take 427.2 g of ferric nitrate, add 1000 g of water, stir to dissolve, and obtain material I. Take 157.3 g of zirconium nitrate, add 500 g of water, heat and stir until dissolved, and obtain material II.

[0080] Mix material I and material II, add 360g of urea, heat to 90℃ with stirring to carry out precipitation reaction, and maintain at 90℃ for 30 minutes; after precipitation is completed, let it age at room temperature for 20 hours; then wash (with water) and separate to obtain the precipitate.

[0081] (2) Under stirring, add 296.7 g of manganese nitrate solution, 100 ml of a solution containing 19.51 g of tetrahydroxygermanium, 200 ml of a solution containing 56.62 g of zinc nitrate, and 62.5 g of 40% (by weight) silica sol material to the above precipitate. Then adjust the pH of the above slurry with ammonia water to make the pH of the mixed slurry = 6.0. After stirring evenly, add 50 g of a solution containing 3.55 g of KOH. After the material is thoroughly stirred, the prepared slurry is subjected to microsphere forming in a spray dryer according to conventional methods. 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:

[0082] 90% Fe by weight 100 Mn 80 Ge 18 Zr 35 Zn 18 K5O x +10 wt% SiO2

[0083] The XPS spectrum of the obtained catalyst is shown in the figure. Figure 1 a. As can be clearly seen from the figure, the displacement of the iron is at 707.5 eV.

[0084]

Example 2

[0085] (1) Take 642.6 g of ferric nitrate, add 1000 g of water, stir and dissolve to obtain material I. Take 135.2 g of zirconium nitrate, add 500 g of water, heat and stir until dissolved to obtain material II.

[0086] Material I and Material II were mixed, and 430 g of urea was added. The mixture was heated to 90°C with stirring to carry out a precipitation reaction, and the temperature was maintained at 90°C for 30 minutes. After precipitation, the mixture was aged at room temperature for 20 hours. Then, the precipitate was obtained by washing (with water) and separating.

[0087] (2) Under stirring, add 223.1 g of manganese nitrate solution, 100 ml of a solution containing 16.31 g of tetrahydroxygermanium, 200 ml of a solution containing 47.32 g of zinc nitrate, and 25.00 g of 40% (by weight) silica sol material to the above precipitate. Then adjust the pH of the above slurry with ammonia water to make the pH of the mixed slurry = 6.0. After stirring evenly, add 50 g of a solution containing 2.13 g of KOH. After the material is thoroughly stirred, the prepared slurry is subjected to microsphere forming in a spray dryer according to conventional methods. 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:

[0088] 96% Fe by weight 100 Mn 40 Ge 10 Zr 20 Zn 10 K2O x +4% by weight SiO2

[0089] The shift of iron in the XPS spectrum of the obtained catalyst is at 708.2 eV.

[0090]

Example 3

[0091] (1) Take 323.9 g of ferric nitrate, add 1000 g of water, stir and dissolve to obtain material I. Take 170.3 g of zirconium nitrate, add 500 g of water, heat and stir until dissolved to obtain material II.

[0092] Mix material I and material II, add 330 g of urea, heat to 90°C with stirring to carry out precipitation reaction, and maintain at 90°C for 30 minutes; after precipitation, let it age at room temperature for 20 hours; then wash (with water) and separate to obtain the precipitate.

[0093] (2) Under stirring, add 337.4 g of manganese nitrate solution, 100 ml of a solution containing 20.54 g of tetrahydroxygermanium, 200 ml of a solution containing 59.62 g of zinc nitrate, and 81.25 g of 40% (by weight) silica sol material to the above precipitate. Then adjust the pH value of the above slurry with ammonia water to make the pH of the mixed slurry = 6.0. After stirring evenly, add 50 g of a solution containing 4.30 g of KOH. After the material is thoroughly stirred, the prepared slurry is subjected to microsphere forming in a spray dryer according to conventional methods. 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:

[0094] 87% Fe by weight 100 Mn 120 Ge 25 Zr 50 Zn 25 K8O x +13% by weight SiO2

[0095] The shift of iron in the XPS spectrum of the obtained catalyst is at 707.1 eV.

[0096]

Example 4

[0097] (1) Take 431.5 g of ferric nitrate, add 1000 g of water, stir to dissolve, and obtain material I. Take 158.8 g of zirconium nitrate, add 500 g of water, heat and stir until dissolved, and obtain material II.

[0098] Mix material I and material II, add 360g of urea, heat to 90℃ with stirring to carry out precipitation reaction, and maintain at 90℃ for 30 minutes; after precipitation is completed, let it age at room temperature for 20 hours; then wash (with water) and separate to obtain the precipitate.

[0099] (2) Under stirring, add 299.6 g of manganese nitrate solution, 100 ml of a solution containing 19.71 g of tetrahydroxygermanium, 100 ml of a solution containing 28.59 g of zinc nitrate, 100 ml of a solution containing 27.70 g of cobalt nitrate, and 62.5 g of 40% (by weight) silica sol material to the above precipitate. Then adjust the pH value of the above slurry with ammonia water to make the pH of the mixed slurry = 6.0. After stirring evenly, add 50 g of a solution containing 3.58 g of KOH. After the material is thoroughly stirred, the prepared slurry is subjected to microsphere forming in a spray dryer according to conventional methods. 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:

[0100] 90% Fe by weight 100 Mn 80 Ge18 Zr 35 Zn9Co9K5O x +10 wt% SiO2

[0101] The XPS spectrum of the obtained catalyst shows an iron shift at 706.8 eV.

[0102]

Example 5

[0103] (1) Take 431.0 g of ferric nitrate, add 1000 g of water, stir and dissolve to obtain material I. Take 158.6 g of zirconium nitrate, add 500 g of water, heat and stir until dissolved to obtain material II.

[0104] Mix material I and material II, add 370 g of urea, heat to 90°C with stirring to carry out precipitation reaction, and maintain at 90°C for 30 minutes; after precipitation, let it age at room temperature for 20 hours; then wash (with water) and separate to obtain the precipitate.

[0105] (2) Under stirring, add 299.3 g of manganese nitrate solution, 100 ml of a solution containing 19.68 g of tetrahydroxygermanium, 200 ml of a solution containing 57.12 g of zinc nitrate, and 62.5 g of 40% (by weight) silica sol material to the above precipitate. Then adjust the pH of the above slurry with ammonia water to make the pH of the mixed slurry = 6.0. After stirring evenly, add 50 g of a solution containing 2.15 g of KOH and 0.80 g of NaOH. After the material is thoroughly stirred, the prepared slurry is subjected to microsphere forming in a spray dryer according to conventional methods. 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:

[0106] 90% Fe by weight 100 Mn 80 Ge 18 Zr 35 Zn 18 K3Na2O x +10 wt% SiO2

[0107] The shift of iron in the XPS spectrum of the obtained catalyst is at 707.1 eV.

[0108] Comparative Example 1

[0109] (1) Take 427.2 g of ferric nitrate, add 1000 g of water, stir to dissolve, and obtain material I. Take 157.3 g of zirconium nitrate, add 500 g of water, heat and stir until dissolved, and obtain material II.

[0110] Mix material I and material II, add 360 grams of urea, heat to 90°C with stirring to carry out precipitation reaction, and maintain at 90°C for 30 minutes.

[0111] (2) Under stirring, add 296.7 g of manganese nitrate solution, 100 ml of a solution containing 19.51 g of tetrahydroxygermanium, 200 ml of a solution containing 56.62 g of zinc nitrate, and 62.5 g of 40% (by weight) silica sol to the above materials. Then adjust the pH of the slurry with ammonia water to make the pH of the mixed slurry = 6.0. After stirring evenly, add 50 g of a solution containing 3.55 g of KOH. After the material is thoroughly stirred, the prepared slurry is subjected to microsphere forming in a spray dryer according to conventional methods. Finally, the microspheres are formed with an inner diameter of 89 mm and a length of 1700 mm. The catalyst was prepared by calcining at 500°C for 2.0 hours in a rotary calcining furnace (mm) to produce a catalyst.

[0112] The XPS spectrum of the obtained catalyst is shown in the figure. Figure 1 b. It is clear from the figure that the iron displacement is at 710.1 eV.

[0113] Comparative Example 2

[0114] Repeat the process of Example 1, except that tetrahydroxygermanium solution is not used in step (2).

[0115] (1) Take 427.2 g of ferric nitrate, add 1000 g of water, stir to dissolve, and obtain material I. Take 157.3 g of zirconium nitrate, add 500 g of water, heat and stir until dissolved, and obtain material II.

[0116] Mix material I and material II, add 360g of urea, heat to 90℃ with stirring to carry out precipitation reaction, and maintain at 90℃ for 30 minutes; after precipitation is completed, let it age at room temperature for 20 hours; then wash (with water) and separate to obtain the precipitate.

[0117] (2) Under stirring, add 296.7 g of manganese nitrate solution, 200 ml of zinc nitrate solution containing 56.62 g, and 62.5 g of 40% (by weight) silica sol material to the above precipitate. Then adjust the pH of the above slurry with ammonia water to make the pH of the mixed slurry = 6.0. After stirring evenly, add 50 g of solution containing 3.55 g of KOH. After the material is thoroughly stirred, 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 prepared by calcining at 500°C for 2.0 hours in a rotary calcining furnace (mm) to produce a catalyst.

[0118] The XPS spectrum of the obtained catalyst shows an iron shift at 705.2 eV.

[0119] Comparative Example 3

[0120] (1) Take 427.2 g of ferric nitrate, add 1000 g of water, stir to dissolve, and obtain material I.

[0121] 360 grams of urea were added to material I and heated to 90°C with stirring to carry out a precipitation reaction, and the temperature was maintained at 90°C for 30 minutes. After precipitation, the mixture was left to age at room temperature for 20 hours. Then, the precipitate was washed and separated to obtain the precipitate.

[0122] (2) Under stirring, add 296.7 g of manganese nitrate solution, 100 ml of a solution containing 19.51 g of tetrahydroxygermanium, 200 ml of a solution containing 56.62 g of zinc nitrate, and 62.5 g of 40% (by weight) silica sol material to the above precipitate. Then adjust the pH of the above slurry with ammonia water to make the pH of the mixed slurry = 6.0. After stirring evenly, add 50 g of a solution containing 3.55 g of KOH. After the material is thoroughly stirred, the prepared slurry is subjected to microsphere forming in a spray dryer according to conventional methods. Finally, the microspheres are formed with an inner diameter of 89 mm and a length of 1700 mm. The catalyst was prepared by calcining at 500°C for 2.0 hours in a rotary calcining furnace (mm) to produce a catalyst.

[0123] The XPS spectrum of the obtained catalyst shows an iron shift at 707.5 eV.

[0124] Comparative Example 4

[0125] Repeat the process of Example 1, except that zinc nitrate solution is not used in step (2).

[0126] (1) Take 427.2 g of ferric nitrate, add 1000 g of water, stir and dissolve to obtain material I. Take 157.3 g of zirconium nitrate, add 500 g of water, heat and stir to dissolve to obtain material II.

[0127] Mix material I and material II, add 360g of urea, heat to 90℃ with stirring to carry out precipitation reaction, and maintain at 90℃ for 30 minutes; after precipitation is completed, let it age at room temperature for 20 hours; then wash (with water) and separate to obtain the precipitate.

[0128] (2) Under stirring, add 296.7 g of manganese nitrate solution, 100 ml of a solution containing 19.51 g of tetrahydroxygermanium, and 62.5 g of 40% (by weight) silica sol material to the above precipitate. Then adjust the pH of the slurry with ammonia water to make the pH of the mixed slurry = 6.0. After stirring evenly, add 50 g of a solution containing 3.55 g of KOH. After the material is thoroughly stirred, the prepared slurry is subjected to microsphere forming in a spray dryer according to conventional methods. Finally, the microspheres are formed with an inner diameter of 89 mm and a length of 1700 mm. The catalyst was prepared by calcining at 500°C for 2.0 hours in a rotary calcining furnace (mm) to produce a catalyst.

[0129] The shift of iron in the XPS spectrum of the obtained catalyst is at 709.2 eV.

[0130] [Experimental Example] Direct Preparation of Low-Carbon Olefins from Syngas

[0131] Experiments were conducted to synthesize low-carbon olefins using the catalysts prepared in the examples and comparative examples, under the following experimental conditions:

[0132] (1) Reduction of the obtained catalyst: The temperature was increased to 300℃ at 3℃ / min using 5 vol% H2 / 95 vol% N2 gas; the catalyst was subjected to a pressure of 1.0 MPa, a catalyst loading of 100 g, and a catalyst loading of 4000 mL·h. -1 ·g -1 Keep at 300℃ for 15 hours.

[0133] (2) Further carbonization of the catalyst: Using a mixture of 20 vol% C2H4 and CO (of which 30 vol% C2H4 and 70 vol% CO) / 80 vol% N2 gas, the temperature is increased to 350°C at a rate of 5°C / min, under a pressure of 1.0 MPa, a catalyst loading of 100 g, and a catalyst loading of 4000 mL·h. -1 ·g -1 Keep at 350℃ for 20 hours.

[0134] (3) The reaction for preparing low-carbon olefins is carried out under the following conditions:

[0135] millimeter fluidized bed reactor

[0136] Reaction temperature 330℃

[0137] Reaction pressure 2.0 MPa

[0138] The catalyst loading amount is equivalent to 100 grams of catalyst before reduction.

[0139] The catalyst loading was based on the amount of catalyst before reduction, at 4000 mL·h. -1 ·g -1

[0140] Raw material ratio (moles): H2 / CO = 3 / 1.

[0141] The experimental results are shown in the table below:

[0142] Table 1

[0143]

[0144]

[0145] As can be seen from the table above, the catalysts in each example have excellent performance: the CO conversion rate is greater than 90%, and the product contains (C2)＝ +C3 ＝ ):C4 ＝ It is greater than 4.0, which is far superior to the corresponding values ​​of each comparison.

[0146] In the product (C2) ＝ +C3 ＝ ):C4 ＝ A higher ratio is better; a higher ratio indicates that the product contains ethylene (C2). ＝ ), propylene (C3) ＝ High content of ) and butene (C4) ＝ The content of ) is low, while the market demand for ethylene and propylene is far greater than the demand for butene.

[0147] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

Claims

1. A catalyst for producing low-carbon olefins from syngas, comprising an active component including iron, manganese, germanium, zirconium, alkali metal, and an alkali metal, wherein the alkali metal is selected from at least one of zinc, cobalt, and nickel; the XPS spectrum of the catalyst has a characteristic peak of 707.5 ± 1.0 eV, attributed to iron; wherein in the catalyst: the molar ratio of manganese to iron is (30~130):100, the molar ratio of germanium to iron is (4~30):100, the molar ratio of zirconium to iron is (10~60):100, the molar ratio of alkali metal to iron is (5~30):100, and the molar ratio of alkali metal to iron is (1~10):

100.

2. The catalyst according to claim 1, characterized in that, The alkali metal is selected from at least one of lithium, sodium, and potassium.

3. The catalyst according to claim 1, characterized in that, In the catalyst: The molar ratio of manganese to iron is (40~120):100; and / or, The molar ratio of germanium to iron is (4~15):100; and / or, The molar ratio of zirconium to iron is (15~40):

100.

4. The catalyst according to claim 1, characterized in that, In the catalyst: The molar ratio of D to iron is (10~25):100; and / or, The molar ratio of alkali metal elements to iron is (2~8):

100.

5. The catalyst according to any one of claims 1 to 4, characterized in that, The catalyst further contains a binder.

6. The catalyst according to claim 5, characterized in that, The adhesive is selected from at least one of silicon dioxide, aluminum oxide, and titanium dioxide.

7. The catalyst according to claim 5, characterized in that, The content of binder is 2 to 15 wt% of 100 wt% of the catalyst.

8. A method for preparing a catalyst for the synthesis of low-carbon olefins from syngas, the preparation method comprising: (1) Mix the solution containing the iron precursor and the solution containing the zirconium precursor to obtain dispersion I; (2) Mix the precipitant with the dispersion I, and after precipitation and aging, obtain dispersion II; (3) Separate the solid phase from dispersion II, wash, and obtain the precipitate; (4) The precipitate is mixed with a solution containing manganese precursor, a solution containing germanium precursor, a solution containing D element precursor, and a binder. The pH is adjusted, and then a solution containing alkali metal element precursor is added. The mixture is then dried and calcined to obtain the catalyst. In step (2), the precipitation is carried out at 50~95℃, and the aging is carried out at room temperature for 12~30h.

9. The preparation method according to claim 8, characterized in that, The iron precursor is selected from at least one of iron nitrate, iron carbonate, and iron oxalate; and / or, the zirconium precursor is selected from at least one of zirconium nitrate, zirconium carbonate, and zirconium oxalate; and / or, the manganese precursor is selected from at least one of manganese nitrate, manganese carbonate, and manganese oxalate; and / or, the germanium precursor is selected from at least one of germanium nitrate, germanium carbonate, and germanium oxalate; and / or, the D element precursor is selected from at least one of D element nitrate, D element carbonate, and D element oxalate; and / or, the alkali metal element precursor is selected from at least one of alkali metal nitrate, alkali metal carbonate, and alkali metal hydroxide.

10. The preparation method according to claim 8, characterized in that, The molar ratio of iron in the iron precursor to zirconium in the zirconium precursor is 100:(10~60); and / or, the molar ratio of iron in the iron precursor to manganese in the manganese precursor is 100:(30~130); and / or, the molar ratio of iron in the iron precursor to germanium in the germanium precursor is 100:(4~30); and / or, the molar ratio of iron in the iron precursor to D in the D element precursor is 100:(5~30); and / or, the molar ratio of iron in the iron precursor to alkali metal in the alkali metal element precursor is 100:(1~10).

11. The preparation method according to claim 8, characterized in that, The molar ratio of iron in the iron precursor to zirconium in the zirconium precursor is 100:(15~40); and / or, the molar ratio of iron in the iron precursor to manganese in the manganese precursor is 100:(40~120); and / or, the molar ratio of iron in the iron precursor to germanium in the germanium precursor is 100:(4~15); and / or, the molar ratio of iron in the iron precursor to D in the D element precursor is 100:(10~25); and / or, the molar ratio of iron in the iron precursor to alkali metal in the alkali metal element precursor is 100:(2~8).

12. The preparation method according to claim 8, characterized in that, The precipitant in step (2) is selected from alkaline precipitants; and / or, In step (4), the adhesive is selected from at least one of silica, alumina, and titanium dioxide; and / or, In step (4), adjust the pH to 1-6; and / or, In step (4), the roasting temperature is 300~800℃ and the time is 2~12h.

13. The preparation method according to claim 12, characterized in that, The precipitant in step (2) is selected from at least one of ammonia, urea, and organic amines.

14. A catalyst obtained by the preparation method according to any one of claims 8 to 13.

15. The application of the catalyst according to any one of claims 1 to 7 or the catalyst obtained by the preparation method according to any one of claims 8 to 13 in the direct preparation of low-carbon olefins from syngas.

16. A method for directly preparing low-carbon olefins from syngas, comprising: In the presence of a catalyst, H2 reacts with CO, wherein the catalyst is selected from the catalysts described in any one of claims 1 to 7 or the catalysts obtained by the preparation method described in any one of claims 8 to 13.

17. The method according to claim 16, characterized in that, The catalyst is first subjected to reduction and carbonization treatment before contact.

18. The method according to claim 16, characterized in that, The reaction temperature is 200–600 °C; and / or the reaction pressure is 0.5–10 MPa; and / or, based on the amount of catalyst before reduction, the volume hourly space velocity of the syngas is 100–8000 mL·h. -1 ·g -1 ; and / or, the H2 / CO molar ratio in the syngas is 0.1~5.

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