Magnetic regulation catalyst, its preparation method and its application in ammonia-hydrogen energy catalytic conversion

Abstract

The application discloses a magnetic regulation catalyst, a preparation method thereof and application of the catalyst in ammonia-hydrogen energy catalytic conversion, and belongs to the technical field of ammonia synthesis and decomposition, and comprises a magnetic component and an electron spin regulation component; the magnetic component is a main magnetic component and / or a secondary magnetic component; the main magnetic component is one or two or more combinations of oxides of iron; the secondary magnetic component is one or two or more combinations of oxides of nickel and oxides of cobalt; and the electron spin regulation component is one or two or more combinations of scandium oxide, yttrium oxide and lanthanide oxides. The electron spin regulation component, as an electron transfer intermediate, is added to the magnetic regulation catalyst to regulate the electron spin state and magnetic moment of the main magnetic component and the secondary magnetic component, so that the catalyst has stronger N2 activation performance under the rapid adjustment of an electromagnetic field, and then the activation energy of N2 is significantly reduced, thereby improving the ammonia synthesis efficiency at low temperature and low pressure.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ammonia synthesis and decomposition, and particularly relates to a magnetic regulation catalyst, a preparation method thereof and ammonia-hydrogen energy catalytic conversion application thereof. BACKGROUND

[0002] At present, large-scale, high-density and long-time storage and cross-regional and low-cost transportation of hydrogen are the main bottlenecks faced by the rapid development of hydrogen energy industry. In recent years, ammonia is increasingly considered as the best hydrogen storage carrier and zero-carbon clean fuel. Ammonia has high energy density, and its volume energy density is about 13.6 MJ / L, 1L of liquid ammonia = 4.5L of high-pressure hydrogen (35.0MPa) = 1200L of normal temperature and pressure hydrogen. Ammonia has a mature technical system, standard specification and low-cost synthesis, storage and transportation, and can realize seasonal, long-distance and "carbon-free" "ammonia-hydrogen" energy storage. Studies have shown that among several types of electrically produced liquid fuels currently studied (liquid hydrogen, liquid ammonia, liquefied natural gas, methanol and organic liquid hydrogen), the cost of ammonia is the lowest, and the efficiency is only second to other electrically produced liquid fuel technologies. Ammonia is highly safe. The fire hazard of ammonia is only class B, and its explosion limit (16% to 25%) is narrower than that of hydrogen (4% to 76%), so it is safer. Its irritating odor is a reliable warning signal. Therefore, the development of ammonia as a hydrogen storage medium is expected to not only solve the problem of traditional high-pressure hydrogen storage and transportation, but also link renewable energy, hydrogen energy and traditional industries, and develop a "hydrogen-ammonia" green circular economy route.

[0003] The ammonia-hydrogen energy catalytic conversion is mainly divided into two reactions of ammonia synthesis and ammonia cracking, which are very dependent on the use of catalysts. The traditional ammonia synthesis catalyst is prepared by using magnetite (Fe3O4) as raw material according to the traditional melting method, and structural promoters mainly containing Al2O3 and SiO2 and electronic promoters mainly containing K2O and CaO are often added during preparation. The structural promoters mainly play a role in inhibiting the continuous growth of Fe microcrystalline grains in a high-temperature atmosphere, and the electronic promoters mainly play a role in improving the ability of Fe-d orbit to provide electrons to adsorbed N2. The structural catalysts such as Al2O3 and CaO are aimed at improving the activity and stability of the catalyst, and the principle is to use these high-melting-point and difficult-to-reduce oxides as spacers for active substances α-Fe crystals. The pore structure, specific surface area and α-Fe grain size of the catalyst have a decisive influence on the activity and stability of the catalyst. The advantages are high reaction activity and low price, but it is limited by the high reaction temperature and pressure and the huge energy consumption. At the same time, due to the low equilibrium concentration of ammonia synthesis at high temperature, it is destined to be inefficient. Compared with the traditional iron-based catalyst, the ruthenium-based catalyst belongs to the supported catalyst. The main difference between the two is the preparation method of the catalyst. The ruthenium-based catalyst is combined with the corresponding oxide by impregnation method to make it exist on the carrier, so as to meet the reaction demand of ammonia synthesis by improving the reduction property of ruthenium-based catalyst. Finally, the infrared dehydration treatment of the catalyst is carried out. The ruthenium-based catalyst can be mass-produced. The noble metal catalyst represented by ruthenium-based catalyst has some similarities with iron-based catalyst. The advantages are low temperature, high activity, small pressure and long service life. However, the ruthenium-based catalyst is limited by the problem of high cost, and cannot be mass-produced and used.

[0004] The ammonia cracking reaction requires a high temperature without the addition of catalyst, and the energy consumption of the system is large, while the presence of catalyst can reduce the temperature required for decomposition. The commonly used catalysts at present are nickel-based catalyst (main active component is single Ni metal) and ruthenium-based catalyst (main active component is single Ru metal). Ruthenium is the highest active catalyst for ammonia cracking reaction, and it is also the most studied ammonia cracking catalyst system. It is found that the addition of Li, Na and Cs in the ruthenium-based catalyst indeed has the ability to promote the catalyst, and the conversion frequency is about twice that of the catalyst without additive when Na and Cs are used, while Li shows the highest promotion. However, due to the fact that Ru is a noble metal, it is difficult to apply it to actual industrial production.

[0005] Nickel is the best performance and the most widely used catalyst in the non-noble metal catalyst for ammonia decomposition, which shows excellent application prospects. In nickel-based system, the appropriate catalyst additives further improve the performance of the catalyst, mainly in enhancing the basicity of the catalyst and enhancing the stability of the catalyst. Common additives mainly include alkali metals (K, Na, Cs), alkaline earth metals (Be, Mg, Ca) and rare earth metals (La, Ce). Although these additives have certain promoting effect on the catalyst, there are still problems such as low activity at low temperature and easy sintering, and there are still many imperfections in the application to industrial production.

[0006] The traditional synthesis of ammonia and ammonia decomposition are both carried out in a single thermal field environment. The reaction gas, reaction intermediate species and catalyst are all in a state of disordered thermal motion under the definition of thermodynamics. The kinetics of the reaction has a strong dependence on the temperature of the system. Under high temperature conditions, the reaction has economically viable kinetics. Under low temperature conditions, there is a strong adsorption and desorption restriction relationship between the catalyst surface and the reaction gas or intermediate species, which is difficult to break through simply by designing new catalysts. Therefore, the synthesis of ammonia at low temperature and low pressure and the decomposition of ammonia at low temperature and high pressure have become scientific problems that have not been solved. By introducing a specific electromagnetic field into the reaction system and developing a ferromagnetic catalyst that has a real-time response to the electromagnetic field, it is expected to break the restriction relationship of the elementary reaction on the surface of the cheap ferromagnetic catalyst at low temperature, low pressure or low temperature and high pressure, thereby solving the problems of low temperature, low pressure synthesis of ammonia and low temperature, high pressure decomposition of ammonia.

[0007] Industrial catalytic synthesis of ammonia must be carried out at high temperature (450-600℃) and high pressure (>15MPa) to be effective, which consumes a lot of energy. The conversion rate of traditional catalysts is low under low temperature (<450℃) and low pressure (<15MPa) conditions. At 350℃ and 0.9MPa, the effect of traditional molten iron catalyst on ammonia synthesis is less than one tenth of that under high temperature and high pressure. Therefore, the development of low-temperature, low-pressure, high-efficiency catalysts is the key to reducing the energy consumption of ammonia synthesis. An ideal low-temperature, low-pressure, high-activity catalyst needs to have low N2 activation energy barrier and low NHx hydrogenation energy barrier at the same time to meet the high efficiency of ammonia synthesis at low temperature and low pressure. However, due to the constraints of the transition metal (TM) surface, this energy barrier assumption is difficult to achieve. The specific expression of the constraint relationship is that the transition metal elements with strong N adsorption also strongly bond NHx. Although strong N adsorption significantly enhances the π electron back-donation effect, greatly reduces the N2 activation energy barrier, but strong NHx adsorption leads to a high hydrogenation energy barrier; and for elements with weak N adsorption, the opposite is true. How to break through the constraint relationship has become the kinetic bottleneck of the development of low-temperature, low-pressure ammonia synthesis. In view of this bottleneck, a new catalytic reaction process and a new catalytic regulation strategy are urgently needed to solve the above bottleneck and improve the efficiency of ammonia synthesis at low temperature and low pressure. SUMMARY

[0008] The present application aims to overcome the problems of the prior art, and provide a magnetic regulation catalyst, a preparation method thereof, and an ammonia-hydrogen energy catalytic conversion application thereof.

[0009] The purpose of the present application is achieved by the following technical solution: a magnetic regulation catalyst, comprising a magnetic component and an electron spin regulation component; the magnetic component is a main magnetic component and / or a secondary magnetic component;

[0010] The main magnetic component is one or a combination of two or more of oxides of iron;

[0011] The secondary magnetic component is one or a combination of two or more of oxides of nickel, oxides of cobalt;

[0012] The electron spin regulation component is one or a combination of two or more of scandium oxide, yttrium oxide, lanthanide oxides.

[0013] In an example, the catalyst further comprises an electron transfer promotion component, which is one or a combination of two or more of lithium oxide, sodium oxide, potassium oxide, rubidium oxide, calcium oxide, cesium oxide, barium oxide.

[0014] In an example, the catalyst further comprises a structural strengthening component, which is one or a combination of two or more of silicon oxide, magnesium oxide, aluminum oxide, chromium oxide, vanadium oxide, titanium oxide.

[0015] In an example, the proportions of the main magnetic component, the secondary magnetic component, the electron spin regulation component, the electron transfer promotion component, and the structural strengthening component are 60-90wt%, 5-30wt%, 0.005-2wt%, 0.005-3wt%, and 0.5-5wt%, respectively.

[0016] In an example, the main magnetic component and the secondary magnetic component in the form of metal oxidation state are replaced by those in the form of metal state.

[0017] It should be further noted that the technical features of each example of the above method can be combined or replaced to form a new technical solution.

[0018] The present application also includes a preparation method of a magnetic regulation catalyst, which is used to prepare the catalyst of any one example or a combination of multiple examples, and the method comprises the following steps:

[0019] Grinding the catalyst raw material;

[0020] Ball milling the ground raw material at a speed of 200r / min-400r / min for 1-3h to realize the mixing treatment of the raw material;

[0021] The raw materials are placed in a water-cooled copper mold and filled with inert gas; the raw materials are preliminarily melted by using an electric arc furnace, the arc current is 10-900 A, the melting time is 80 s-100 h, and the arc is uniformly rotated around the filler during melting;

[0022] The molten raw materials are cooled to room temperature at a speed of 10-300 ℃ / min to obtain solid molten materials;

[0023] The solid molten materials are crushed and screened to obtain the catalyst.

[0024] In an example, the method comprises:

[0025] 2-5 g of the catalyst is weighed and placed in a fixed bed reactor;

[0026] The reactor is pre-reduced by flowing hydrogen, and the reactor is raised from the initial temperature of 18-22 ℃ to 190-210 ℃ in 35-45 min, maintained for 25-35 min, then raised to 490-510 ℃ in 145-155 min, maintained for 9.5-10.5 h, the reaction pressure is 0.9-10 bar, and the hydrogen flow is 100-1000 mL / min;

[0027] The reactor is cooled to room temperature to obtain the catalyst after pre-reduction.

[0028] The application of the magnetic regulation catalyst in ammonia-hydrogen energy catalytic conversion is based on any of the above catalyst examples or a combination of multiple catalyst examples, or based on the preparation method formed by combining any of the above examples or multiple examples, comprising the following steps:

[0029] 2 g-5 g of the catalyst is weighed and loaded into a fixed bed reactor;

[0030] Nitrogen and hydrogen are introduced for ammonia synthesis reaction, the nitrogen flow is 15-150 mL / min, the hydrogen flow is 45-350 mL / min, the nitrogen to hydrogen flow ratio is 1:2-1:3, and a heat field, a magnetic field, an electric field, or a heat field and an electromagnetic field are applied to the nitrogen, hydrogen and catalyst; the reaction temperature is 100-500 ℃, the pressure is 1-10 MPa; the electromagnetic field applied voltage is 1-150 kV, the applied current is 10-5000 mA, the frequency is 10 Hz-1 MHz, and the magnetic field strength is 9 mT-1 T.

[0031] The application of the magnetic regulation catalyst in ammonia-hydrogen energy catalytic conversion is based on any of the above catalyst examples or a combination of multiple catalyst examples, or based on the preparation method formed by combining any of the above examples or multiple examples, comprising the following steps:

[0032] 1-10g of the catalyst is weighed and loaded into a fixed bed reactor;

[0033] The ammonia decomposition reaction is carried out by introducing ammonia gas, the ammonia gas flow is 200-400 mL / min, and a heat field, a magnetic field, an electric field or a heat field and an electromagnetic field are applied to the ammonia gas and the catalyst; the reaction temperature is 100-1000 DEG C, the pressure is 0.01-5 MPa; the electromagnetic field applied voltage is 5-100 kV, the applied current is 50-2000 mA, the frequency is 100 Hz-1 MHz, and the magnetic field strength is 7 mT-0.9 T.

[0034] Compared with the prior art, the present application has the following advantages:

[0035] 1. In an example, an electron spin regulating component as an electron transfer intermediate is added to the magnetic regulation catalyst, the electron spin state and magnetic moment of the main magnetic component and the auxiliary magnetic component are regulated, so that the catalyst has stronger N2 activation performance under the rapid adjustment of the electromagnetic field, thereby significantly reducing the activation energy of N2, thereby improving the ammonia synthesis efficiency at low temperature and low pressure; at the same time, the main magnetic component exists in the form of an oxide, the formed crystal grains are finer after melting, and the crystal structure is more stable, which is beneficial to fully disperse other components in the crystal phase; the auxiliary magnetic component exists in the form of an oxide, which is more easily combined with the metal ions in the main magnetic component in the crystal gap, and the electron transfer efficiency of the main magnetic component is enhanced by the change of the magnetic property of the auxiliary magnetic component in the high-temperature magnetic field, the work function is reduced, and the catalytic activity is enhanced.

[0036] 2. In an example, an electron transfer promoting component is added to the magnetic regulation catalyst, which is uniformly distributed on the surface of alpha-Fe, reduces the electron work function of the iron surface, and promotes the desorption and adsorption of ammonia.

[0037] 3. In an example, a structure strengthening component is added to the magnetic regulation catalyst, and the metal ions in the structure strengthening component enter the oxygen ion dense packing tetrahedron and octahedron gap of the spinel structure, which plays a role in isolating alpha-Fe, makes the crystal grains smaller and more stable, and improves the catalyst activity and stability.

[0038] 4. In an example, during the preparation of the catalyst, the introduction of inert gas can avoid redox reaction; by adjusting the arc temperature through the current, an extremely high temperature (about 2000 DEG C) can be instantly reached, the molten material can be quickly changed into a liquid state, and the turbulent motion is more obvious at the extremely high temperature, so that the molten material is fully mixed and uniform in the liquid state; rapidly cooling to room temperature at a speed of about 200 DEG C / min, this process makes the liquid molten material which has been mixed and uniform quickly cool to solid state, and because the solidification time is extremely short, the crystal phase can be quickly fixed, finally making the catalyst components mixed uniformly.

[0039] 5. In an example, by pre-reducing the metal oxide state catalyst to obtain a catalyst in the form of a metal state, a catalyst with alternative existence forms is provided.

[0040] 6. In an example, in the ammonia synthesis reaction, cobalt or nickel atoms are uniformly distributed in the α-Fe, which makes the α-Fe crystal grains significantly smaller, the lattice is distorted, promotes more Fe

[111] surface exposure, increases the number of active centers, and at the same time improves the pore structure, the number of 40-70A0 micropores increases, which is beneficial to the transfer of reactants and products, and at the same time enhances the low-temperature activity of the iron catalyst. At the same time, cobalt or nickel as a secondary magnetic component of the ferromagnetic state metal under the regulation of the electromagnetic field, the d-band lone electron orbit of α-Fe forms a bonding electron domain with the bonding orbit of nitrogen and hydrogen molecules faster, so as to improve the ammonia synthesis efficiency at low temperature and low pressure. BRIEF DESCRIPTION OF DRAWINGS

[0041] The specific embodiments of the present application will be further described in conjunction with the accompanying drawings, which are used to provide further understanding of the present application, and form a part of the present application. In these drawings, the same reference numerals represent the same or similar parts. The schematic embodiments of the present application and their descriptions are used to explain the present application, and do not constitute an improper limitation on the present application.

[0042] Figure 1 A schematic diagram of the composition of the catalyst provided for an example of the present application is shown.

[0043] Figure 2 A schematic diagram of the composition of the catalyst provided for a preferred example of the present application is shown. DETAILED DESCRIPTION

[0044] The technical solutions of the present application will be described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0045] In the description of the present application, it should be noted that the directions or positional relationships indicated by "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like are based on the directions or positional relationships described in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the ordinal numbers (such as "first and second", "first to fourth", etc.) are used to distinguish objects, and are not limited to the order, and cannot be understood as indicating or implying relative importance.

[0046] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0047] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0048] In one example, a magnetically modulated catalyst, such as Figure 1 As shown, it includes magnetic components and electron spin modulation components; the magnetic components include primary magnetic components and secondary magnetic components. The magnetic components and electron spin modulation components are melted together under high temperature (1600-2100℃) and then cooled to form a magnetically modulated catalyst.

[0049] The main magnetic component is one or a combination of two or more of the following: iron(III) oxide (Fe3O4), iron(II) oxide (Fe2O3), and ferrous(II) oxide (FeO). Compared with directly using metals and alloys, the main magnetic component has the advantage of forming finer grains and a more stable crystal structure by melting in the form of oxides, which is conducive to the full dispersion of other components in the crystal phase.

[0050] Furthermore, the secondary magnetic component is one or a combination of two or more of nickel tetroxide (Ni3O4), nickel oxide (Ni2O3), nickel suboxide (NiO), cobalt tetroxide (Co3O4), cobalt oxide (Co2O3), and cobalt suboxide (CoO). Compared to directly using metals and alloys, the advantage of the secondary magnetic component is that the oxide form makes it easier for its metal ions to combine with the metal ions in the primary magnetic component in the crystal voids. In a high-temperature magnetic field, the change in the magnetism of the secondary magnetic component enhances the electron transfer efficiency of the primary magnetic component, reduces the work function, and enhances catalytic activity.

[0051] Furthermore, the electron spin modulation component is one or a combination of two or more of the following: lanthanum oxide, cerium oxide, yttrium oxide, terbium oxide, samarium oxide, praseodymium oxide, neodymium oxide, holmium oxide, gadolinium oxide, erbium oxide, scandium oxide, dysprosium oxide, thulium oxide, ytterbium oxide, lutetium oxide, europium oxide, scandium oxide, and promethium oxide. As an electron transfer intermediate, the electron spin modulation component increases the range of α-Fe electron spin motion, raising its Fermi level and enabling more rapid bonding under rapid electromagnetic field modulation.

[0052] In an example, the catalyst further comprises an electron transfer promoting component, which is one or a combination of two or more of lithium oxide, sodium oxide, potassium oxide, rubidium oxide, calcium oxide, cesium oxide, barium oxide. The electron transfer promoting component is uniformly distributed on the surface of the alpha-Fe, which reduces the electron work function of the iron surface and promotes the desorption and adsorption of ammonia.

[0053] In an example, the catalyst further comprises a structure strengthening component, which is one or a combination of two or more of silicon oxide, magnesium oxide, aluminum oxide, chromium oxide, vanadium oxide, titanium oxide. The structure strengthening component enters the oxygen ion dense-packed tetrahedron and octahedron voids of the spinel structure, which plays a role of isolating alpha-Fe, makes the crystal grains smaller and stable, and improves the activity and stability of the catalyst.

[0054] In an example, the proportions of the main magnetic component, the auxiliary magnetic component, the electron spin regulating component, the electron transfer promoting component, and the structure strengthening component are 60-90wt%, 5-30wt%, 0.005-2wt%, 0.005-3wt%, and 0.5-5wt%, respectively.

[0055] In an example, the main magnetic component and the auxiliary magnetic component in the metal oxide state are replaced by the metal state. The catalyst of the present application has two structures, one structure in which the main magnetic component and the auxiliary magnetic component exist in the metal oxide state, and the other structure in which the main magnetic component and the auxiliary magnetic component exist in the metal state. The catalyst structure in which the main magnetic component and the auxiliary magnetic component exist in the metal oxide state is reduced by hydrogen to obtain the catalyst in which the main magnetic component and the auxiliary magnetic component exist in the metal state.

[0056] The above examples are combined to obtain a preferred example of the present application, as shown in Figure 2 The magnetic regulation catalyst comprises a main magnetic component, an auxiliary magnetic component, an electron spin regulating component, an electron transfer promoting component, and a structure strengthening component. The above components are melted together under high temperature conditions and form the magnetic regulation catalyst after cooling.

[0057] The present application also comprises a preparation method of a magnetic regulation catalyst, which is used to prepare the catalyst formed by any one of the above examples or a combination of multiple examples. The preparation method comprises the following steps:

[0058] S1: grinding treatment is performed on the catalyst raw material;

[0059] S2: the ground raw material is ball milled at a speed of 200r / min-400r / min for 1-3h to realize the mixing treatment of the raw material;

[0060] S3: Put the raw materials in a water-cooled copper mold and fill with inert gas; use an electric arc furnace to preliminarily melt the raw materials, the arc current is 10-900 A, and the melting time is 80 s-100 h; then adjust the arc current to 10-900 A for melting for 80 s-100 h, and the arc rotates uniformly around the filler during melting;

[0061] S4: Cool the melted raw materials to room temperature at a speed of 10 ℃ / min-300 ℃ / min to obtain solid molten materials;

[0062] S5: Crush and screen the solid molten materials to obtain the catalyst.

[0063] In step S1, the raw materials are ground using aagate mortar, and a certain proportion of the raw materials is placed in the mortar for grinding for 30 min. The raw materials can be magnetic components and electron spin regulation components, or can be magnetic components, electron spin regulation components, electron transfer promotion components, and structure strengthening components.

[0064] In step S2, the raw materials are mixed using a planetary ball mill. The ground raw materials are placed in a ball mill tank and ground at a speed of 200 r / min-400 r / min for 1-3 h. Further, the planetary ball mill moves in X and Y space 360° constantly changing position through the planetary disc, and under the action of the geometry of the grinding carrier and the special movement mode, high-frequency and high-intensity collisions, shearing and friction between the grinding medium and the sample (raw materials) are generated, which ultimately makes the sample achieve excellent grinding effect, with the characteristics of fast processing speed, small and uniform sample size.

[0065] In step S3, the raw materials are melted using a vacuum high-temperature alloy micro electric arc furnace, and the melting temperature is adjusted by controlling the electric arc furnace current. The ball-milled raw materials are placed in a water-cooled copper mold, and argon is filled to -0.05 MPa. An arc is struck with a current of 20 A, and after the arc is stabilized, it is adjusted to 80 A (about 1700 ℃) for preliminary melting for 3 min. After the filler is completely melted, the current is increased to 140 A (about 2000 ℃) to fully melt the filler, and the current is maintained for 3 min. During this period, the arc rotates uniformly around the filler, so that the filler is uniformly heated, and the hot turbulent flow is fully flowing, and the various additives are uniformly distributed. Further, through the direct pump and molecular pump system, the vacuum chamber where the ball-milled raw materials are located is pumped to a low vacuum state (≤6.67.0*10 -3 Pa), and then high-purity argon is filled to maintain the vacuum chamber in an inert atmosphere, so that the high-temperature melting without oxygen does not occur. Further, by controlling the current size to adjust the arc temperature, an extremely high temperature (about 2000 ℃) can be instantly reached, which can quickly make the molten material become liquid, and the turbulent flow is more obvious at an extremely high temperature, so that the molten material is fully mixed and uniform in the liquid state.

[0066] In step S4, the cooling uses a water-cooled copper mold. After the smelting is stopped, the molten material is rapidly cooled to room temperature at a rate of 200℃ / min under the rapid circulation of cold water, forming a hemispherical molten material. Further, the water-cooled copper mold is rapidly cooled to room temperature at a rate of 200℃ / min through the rapid circulation of cold water, which rapidly cools the liquid molten material that has been uniformly mixed into a solid state. Because the solidification time is extremely short, the crystal phase can be quickly fixed, and the final catalyst components are uniformly mixed.

[0067] In step S5, the crushing uses a zirconia / tungsten carbide / corundum double-roller crusher. The above hemispherical molten material is first lightly hit with a hammer to break it into pieces of about 10mm, and then added to the zirconia double-roller crusher for extrusion crushing to particles of 0.01mm-5mm. The particle sorting uses a screen to sort the ammonia synthesis catalyst. The above particles of 0.01mm-5mm are sieved using a 6-18 mesh screen.

[0068] In an example, the preparation method further comprises reducing the obtained catalyst structure in the form of a metal oxidation state by hydrogen to obtain a catalyst in the form of a metal state, and the pre-reduction comprises the following steps:

[0069] S6: 2g-5g of the catalyst is weighed and placed in a quartz fixed bed reactor;

[0070] S7: The pre-reduction treatment is performed by flowing hydrogen, the reactor is raised from the initial temperature of 18-22℃ to 190-210℃ in 35-45min, maintained for 25-35min, then raised to 490-510℃ in 145-155min, maintained for 9.5-10.5h, the reaction pressure is 0.9-10bar, and the hydrogen flow rate is 100-1000mL / min;

[0071] S8: The reactor is cooled to room temperature, the reactor is disassembled, the catalyst is poured into an aluminum tray, and the catalyst in the above aluminum tray is placed in a vacuum drying box for storage.

[0072] The application also includes an ammonia synthesis method based on a magnetically controlled catalyst, which is applied based on the catalyst formed according to any one of the above examples or a combination of multiple examples, or a catalyst prepared based on the preparation method according to any one of the above examples or a combination of multiple examples, and comprises the following steps:

[0073] 2g-5g of the catalyst is weighed and loaded into a quartz fixed bed reactor;

[0074] The ammonia synthesis reaction is carried out by introducing nitrogen and hydrogen, the flow rate of nitrogen is 15-150 mL / min, the flow rate of hydrogen is 45-350 mL / min, the flow rate ratio of nitrogen to hydrogen is 1:2-1:3, and a thermal field, a magnetic field, an electric field or a thermal field and an electromagnetic field are applied to the nitrogen, hydrogen and catalyst; the reaction temperature is 100-500 DEG C, the pressure is 1-10 MPa; the voltage of the electromagnetic field is 1-150 kV, the applied current is 10-5000 mA, the frequency is 10 Hz-1 MHz, and the magnetic field strength is 9 mT-1 T.

[0075] Specifically, the four iron oxide is used as the main magnetic component, the four cobalt oxide and the nickel oxide are used as the auxiliary magnetic component, the lanthanum oxide is used as the electronic spin regulation component, the potassium oxide and the calcium oxide are used as the electronic transfer promotion component, and the aluminum oxide and the silicon oxide are used as the structure strengthening component. The above components are placed in an agate mortar as raw materials for grinding, and then the ground raw materials are mixed in a planetary ball mill. The mixed raw materials are placed in a vacuum alloy micro-arc furnace for melting, and then cooled in a water-cooled copper mold after melting is stopped. The cooled melt is lightly tapped into 10 mm pieces with a hammer, and then crushed to 0.01-5 mm particles with a zirconia double-roller crusher, and finally the particles are sorted by using 6-mesh and 18-mesh screens. The sorted material is an ammonia synthesis catalyst, and after filling, pre-reducing and discharging, 2g of the catalyst is weighed and filled in a quartz fixed-bed reactor. The reaction temperature is first increased from 20 DEG C to 500 DEG C, and then decreased to 350 DEG C, the pressure is 0.9 MPa, and the ammonia synthesis reaction is carried out by introducing nitrogen and hydrogen. The ammonia concentration at the outlet of the reactor is measured by using a laser ammonia analyzer during the reaction, and after the reading is stable, an electromagnetic field is applied to the reactor. The ammonia concentration at the outlet of the reactor is continuously measured until the reading is stable.

[0076] The catalytic mechanism of the application is that: the cobalt atoms are uniformly distributed in the alpha-Fe, the alpha-Fe grain is obviously smaller, the lattice is distorted, more Fe

[111] surfaces are exposed, the number of active centers is increased, the pore structure is improved, the number of 40-70 A0 micropores is increased, which is beneficial to the transfer of reactants and products, and the low-temperature activity of the iron catalyst is enhanced. At the same time, the cobalt as the auxiliary magnetic component of the ferromagnetic metal is adjusted under the electromagnetic field, the d-band lone electron orbit of alpha-Fe forms a bonding electron domain with the bonding orbit of nitrogen and hydrogen molecules faster, so that the ammonia synthesis efficiency is improved at low temperature and low pressure.

[0077] Nickel is a ferromagnetic metal at room temperature, when it exceeds 356.7 ℃ (Curie temperature), nickel is converted from ferromagnetic state to paramagnetic state, it will be easier to control the movement of α-Fe electron by controlling magnetic field, make the catalyst Fermi level rise, work function decrease, electron more easily enter N2 anti-bonding orbital to promote its broken bond, also more easily fill single electron in N2, H2 front molecular orbital into the orbital containing lone electron in iron atom d band, rapidly form Fe-N bond and Fe-H bond on the surface of catalyst, and then can realize the regulation of catalytic synthesis process. At the same time, the presence of nickel metal promotes the adsorption of H2 and the desorption of NH X .

[0078] The uniform distribution of lanthanum oxide in α-Fe crystal grains improves the range of α-Fe electron spin movement as an electron transfer intermediate, makes its Fermi level rise, and forms bond more quickly under the rapid adjustment of electromagnetic field.

[0079] Further, the mass fraction of ferroferric oxide is 95.6%, the mass fraction of ferrocobalt oxide is 0.5%, the mass fraction of nickel oxide is 0.05%, and the mass fraction of lanthanum oxide is 0.05%. The mass fraction of potassium oxide is 1%, the mass fraction of calcium oxide is 1%, the mass fraction of aluminum oxide is 1.5%, and the mass fraction of silicon oxide is 0.35%.

[0080] Further, the rotation speed of the planetary ball mill is 400 r / min, and the time is 2 h.

[0081] Further, the arc furnace uses 20 A current to arc, 80 A current (about 1700 ℃) to preliminarily melt, and the time is 3 min. Then use 140 A current to fully melt, and the time is 3 min. Further, the cooling process speed is 200 ℃ / min.

[0082] Further, the pre-reduction reactor temperature is 500 ℃, the pressure is 1 bar, the hydrogen flow rate is 200 ml / min, and the time is 10 h. Further, the reactor temperature rising program is that the initial temperature is 20 ℃, which rises to 200 ℃ after 40 min, keeps at 200 ℃ for 30 min, then rises to 500 ℃ after 150 min, and keeps at 500 ℃ for 10 h.

[0083] Further, the ammonia synthesis reaction temperature program is that the reactor temperature rising program is that the initial temperature is 20 ℃, which rises to 200 ℃ after 40 min, keeps at 200 ℃ for 30 min, then rises to 500 ℃ after 150 min, and keeps at 500 ℃ for 30 min, then reduces to 350 ℃ after 30 min.

[0084] Further, the nitrogen flow rate is 50 ml / min, and the hydrogen flow rate is 150 ml / min.

[0085] Further, the electromagnetic field parameters are: applied voltage 9.5 kV, applied current 190.0 mA, frequency 8.4 kHz, and magnetic field intensity 100 mT.

[0086] The application also includes an ammonia decomposition method based on a magnetically regulated catalyst, which is formed based on any one of the above examples or a combination of multiple examples, or is prepared based on a preparation method formed based on any one of the above examples or a combination of multiple examples, and includes the following steps:

[0087] 6-10 g of the catalyst is weighed and loaded into a quartz fixed-bed reactor;

[0088] 4%-6% of ammonia gas is introduced for ammonia decomposition reaction, the ammonia gas flow is 200-400 mL / min, and a thermal field, a magnetic field, an electric field, or a thermal field and an electric field are applied to the ammonia gas and the catalyst; the reaction temperature is 100-1000 DEG C, the pressure is 0.01-5 MPa; the electromagnetic field has an applied voltage of 5-100 kV, an applied current of 50-2000 mA, a frequency of 100 Hz-1 MHz, and a magnetic field intensity of 7 mT-0.9 T. The above components are used as raw materials, placed in an agate mortar for raw material grinding, and then the ground raw materials are mixed in a planetary ball mill. The mixed raw materials are placed in a vacuum alloy micro-arc furnace for raw material melting, and after melting is stopped, the molten material is cooled in a water-cooled copper mold. The cooled molten material is lightly tapped into 10 mm or so pieces with a hammer, and then broken into 0.01-5 mm particles with a zirconia double-roller crusher, and finally, particle sorting is performed using 6-mesh and 18-mesh screens. The sorted material is an ammonia decomposition catalyst, and after filling, pre-reduction, and unloading, 8 g of the catalyst is weighed and loaded into a quartz fixed-bed reactor. The reaction temperature is 300 DEG C, 350 DEG C, 400 DEG C, 450 DEG C, 500 DEG C, 550 DEG C, or 600 DEG C, the pressure is 0.53 MPa, and 5% of ammonia gas is introduced for ammonia decomposition reaction. During the reaction process, a laser ammonia analyzer is used to measure the ammonia concentration at the reactor outlet, and after the reading is stable, an electromagnetic field is applied to the reactor. The ammonia concentration at the reactor outlet is continuously measured until the reading is stable.

[0089] The catalytic mechanism of the application is as follows:

[0090] The nickel-iron bimetallic catalyst is a new non-noble metal catalyst for ammonia decomposition reaction. Through the interaction between nickel and iron, more defects are generated on the surface of the catalyst, thereby increasing the adsorption of ammonia and changing the rate-limiting step of the ammonia decomposition reaction. The nickel-iron bimetallic catalyst with cerium oxide as the carrier can regulate the d-band center of the active site and significantly improve the catalytic performance of ammonia cracking. Importantly, the nickel-iron alloy can form metal particles with a diameter of 5-10 nm on the cerium oxide carrier, greatly exposing the active area. Under the regulation of the electromagnetic field, the highly dispersed active sites can enhance the hydrogen removal capacity, thereby making the nickel-iron bimetallic particles have high hydrogen generation activity. After adding three kinds of additives, namely, electron spin regulation component, electron transfer promotion component and structure strengthening component, they are doped into the nickel-iron bimetallic lattice, thereby exposing more oxygen vacancies to the catalyst, which is the reason why the catalyst has high ammonia decomposition activity, thereby improving the ammonia decomposition efficiency.

[0091] Further, the mass fraction of ferric oxide is 38.46%, the mass fraction of nickel oxide is 57.64%, the mass fraction of cerium oxide is 0.05%, the mass fraction of potassium oxide is 1%, the mass fraction of calcium oxide is 1%, the mass fraction of aluminum oxide is 1.5%, and the mass fraction of silicon oxide is 0.35%.

[0092] Further, the planetary ball mill rotates at a speed of 400 r / min for 2 h.

[0093] Further, the arc furnace is ignited with a current of 20 A, and the preliminary melting is carried out with a current of 80 A (about 1700℃) for 3 min. Then, the sufficient melting is carried out with a current of 140 A for 3 min. Further, the cooling process is carried out at a speed of 200℃ / min.

[0094] Further, the pre-reduction reactor temperature is 700℃, the pressure is 1 bar, the hydrogen flow rate is 100 ml / min, and the time is 12 h. Further, the reactor temperature program is that the initial temperature is 20℃, and it is raised to 500℃ for 100 min, then to 700℃ for 40 min, and kept at 700℃ for 12 h.

[0095] Further, the ammonia decomposition reaction temperature program is that the reactor temperature program is that the initial temperature is 20℃, and it is raised to 300℃ for 60 min, then the temperature raising rate is 5℃ / min for every 50℃.

[0096] Further, the ammonia flow rate is 380 ml / min.

[0097] Further, the electromagnetic field parameters are that the applied voltage is 8.2 kV, the applied current is 172.0 mA, the frequency is 8.0 kHz, and the magnetic field strength is 80 mT.

[0098] To illustrate the promoting effect of the magnetic regulation catalyst on ammonia synthesis and decomposition, the following ammonia synthesis and decomposition experiments and control experiments are given:

[0099] Example 1

[0100] Nitrogen and hydrogen were used as raw materials, Fe3O4 / Co3O4 / Ni2O3 / Al2O3 / SiO2 / K2O / La2O3 / CeO2 multi-component material was used as catalyst, and a thermal field, a magnetic field and an electric field were applied to nitrogen, hydrogen and the catalyst at the same time, or a thermal field and an electromagnetic field were applied to nitrogen, hydrogen and the catalyst at the same time. The total gas pressure of nitrogen and hydrogen was 3.0 MPa; the molar ratio of nitrogen and hydrogen was 1:3. The temperature of the applied thermal field was 350°C; the strength of the electric field was 9 kV (8.4 KHz); the strength of the magnetic field was 100 Gs (10 KHz). The actual outlet concentration of ammonia is shown in Table 1.

[0101] Example 2

[0102] Nitrogen and hydrogen were used as raw materials, Fe3O4 / Co3O4 / Ni2O3 / Al2O3 / SiO2 / K2O / La2O3 / CeO2 multi-component material was used as catalyst, and a thermal field, a magnetic field and an electric field were applied to nitrogen, hydrogen and the catalyst at the same time, or a thermal field and an electromagnetic field were applied to nitrogen, hydrogen and the catalyst at the same time. The total gas pressure of nitrogen and hydrogen was 5.0 MPa; the molar ratio of nitrogen and hydrogen was 1:3. The temperature of the applied thermal field was 350°C; the strength of the electric field was 12 kV (10 KHz); the strength of the magnetic field was 150 Gs (10 KHz). The actual outlet concentration of ammonia is shown in Table 1.

[0103] Example 3

[0104] Nitrogen and hydrogen were used as raw materials, Fe3O4 / Co3O4 / Ni2O3 / Al2O3 / SiO2 / K2O / La2O3 / CeO2 multi-component material was used as catalyst, and a thermal field, a magnetic field and an electric field were applied to nitrogen, hydrogen and the catalyst at the same time, or a thermal field and an electromagnetic field were applied to nitrogen, hydrogen and the catalyst at the same time. The total gas pressure of nitrogen and hydrogen was 7.0 MPa; the molar ratio of nitrogen and hydrogen was 1:3. The temperature of the applied thermal field was 350°C; the strength of the electric field was 15 kV (12 KHz); the strength of the magnetic field was 200 Gs (10 KHz). The actual outlet concentration of ammonia is shown in Table 1.

[0105] Example 4

[0106] Example 1

[0107] Example 2

[0108] Example 3

[0109] Example 4

[0110] Example 5

[0111] Comparative Example 1

[0112] Comparative Example 2

[0113] Comparative Example 3

[0114] Nitrogen and hydrogen were used as raw materials, Fe3O4 / Co3O4 / Ni2O3 / Al2O3 / SiO2 / K2O / La2O3 / CeO2 multi-component material was used as catalyst, and only heat field was applied to nitrogen, hydrogen and catalyst. The total gas pressure of nitrogen and hydrogen was 5 MPa; the molar ratio of nitrogen and hydrogen was 1:3. The temperature of the applied heat field was 350℃; the actual outlet concentration of ammonia was shown in Table 1.

[0115] Comparative Example 3

[0116] Nitrogen and hydrogen were used as raw materials, Fe3O4 / Co3O4 / Ni2O3 / Al2O3 / SiO2 / K2O / La2O3 / CeO2 multi-component material was used as catalyst, and only heat field was applied to nitrogen, hydrogen and catalyst. The total gas pressure of nitrogen and hydrogen was 7 MPa; the molar ratio of nitrogen and hydrogen was 1:3. The temperature of the applied heat field was 350℃; the actual outlet concentration of ammonia was shown in Table 1.

[0117] Comparative Example 4

[0118] Nitrogen and hydrogen were used as raw materials, Fe3O4 / Co3O4 / Ni2O3 / Al2O3 / SiO2 / K2O / La2O3 / CeO2 multi-component material was used as catalyst, and only heat field was applied to nitrogen, hydrogen and catalyst. The total gas pressure of nitrogen and hydrogen was 5 MPa; the molar ratio of nitrogen and hydrogen was 1:3. The temperature of the applied heat field was 450℃; the actual outlet concentration of ammonia was shown in Table 1.

[0119] Comparative Example 5

[0120] Nitrogen and hydrogen were used as raw materials, Fe3O4 / Co3O4 / Ni2O3 / Al2O3 / SiO2 / K2O / La2O3 / CeO2 multi-component material was used as catalyst, and only heat field was applied to nitrogen, hydrogen and catalyst. The total gas pressure of nitrogen and hydrogen was 7 MPa; the molar ratio of nitrogen and hydrogen was 1:3. The temperature of the applied heat field was 450℃; the actual outlet concentration of ammonia was shown in Table 1.

[0121] Comparative Example 6

[0122] Nitrogen and hydrogen were used as raw materials, Fe3O4 / Co3O4 / Ni2O3 / Al2O3 / SiO2 / K2O / La2O3 / CeO2 multi-component material was used as catalyst, and only heat field was applied to nitrogen, hydrogen and catalyst. The total gas pressure of nitrogen and hydrogen was 10 MPa; the molar ratio of nitrogen and hydrogen was 1:3. The temperature of the applied heat field was 450℃; the actual outlet concentration of ammonia was shown in Table 1.

[0123] Comparative Example 7

[0124] Example 1 100% of ammonia gas was used as a raw material, Fe3O4 / Co3O4 / Ni2O3 / Al2O3 / SiO2 / K2O / La2O3 / Y2O3 multicomponent material was used as a catalyst, and only a thermal field was applied to the ammonia gas and the catalyst. The gas pressure of the ammonia gas was 2 MPa. The temperature at which the thermal field was applied was 400°C. The actual decomposition rate of the ammonia is shown in Table 2.

[0125] Comparative Example 8

[0126] 100% of ammonia gas was used as a raw material, Fe3O4 / Co3O4 / Ni2O3 / Al2O3 / SiO2 / K2O / La2O3 / Y2O3 multicomponent material was used as a catalyst, and only a thermal field was applied to the ammonia gas and the catalyst. The gas pressure of the ammonia gas was 2 MPa. The temperature at which the thermal field was applied was 450°C. The actual decomposition rate of the ammonia is shown in Table 2.

[0127] Comparative Example 9

[0128] 100% of ammonia gas was used as a raw material, Fe3O4 / Co3O4 / Ni2O3 / Al2O3 / SiO2 / K2O / La2O3 / Y2O3 multicomponent material was used as a catalyst, and only a thermal field was applied to the ammonia gas and the catalyst. The gas pressure of the ammonia gas was 2 MPa. The temperature at which the thermal field was applied was 500°C. The actual decomposition rate of the ammonia is shown in Table 2.

[0129] Comparative Example 10

[0130] 100% of ammonia gas was used as a raw material, Fe3O4 / Co3O4 / Ni2O3 / Al2O3 / SiO2 / K2O / La2O3 / Y2O3 multicomponent material was used as a catalyst, and only a thermal field was applied to the ammonia gas and the catalyst. The gas pressure of the ammonia gas was 2 MPa. The temperature at which the thermal field was applied was 550°C. The actual decomposition rate of the ammonia is shown in Table 2.

[0131] Comparative Example 11

[0132] 100% of ammonia gas was used as a raw material, Fe3O4 / Co3O4 / Ni2O3 / Al2O3 / SiO2 / K2O / La2O3 / Y2O3 multicomponent material was used as a catalyst, and only a thermal field was applied to the ammonia gas and the catalyst. The gas pressure of the ammonia gas was 2 MPa. The temperature at which the thermal field was applied was 600°C. The actual decomposition rate of the ammonia is shown in Table 2.

[0133] Table 1 Actual exit concentration of ammonia results of Examples 1 to 3 and Comparative Examples 1 to 6

[0134]

[0135] Table 2 Ammonia decomposition rate results of Examples 4 to 6 and Comparative Examples 7 to 11

[0136]

[0137] As can be seen from Tables 1 and 2, the ammonia synthesis and decomposition efficiency is greatly improved under the same conditions after using the catalyst of the present application, and effective ammonia synthesis and decomposition at low temperature and low pressure is realized.

[0138] The above detailed description is a detailed description of the present application, and cannot be considered as limiting the specific embodiments of the present application to these descriptions. For those skilled in the art to which the present application belongs, without departing from the concept of the present application, a number of simple deductions and substitutions can be made, which should be considered as falling within the protection scope of the present application.

Claims

1. A magnetic regulatory catalyst for the catalytic conversion application of ammonia-hydrogen energy sources, characterized by, The magnetic regulation catalyst is prepared by a melting method, and comprises a magnetic component and an electron spin regulation component. The main magnetic component is one or more than two combinations of oxides of iron. The auxiliary magnetic component is one or more than two combinations of oxides of nickel and oxides of cobalt. The electron spin regulation component is one or more than two combinations of scandium oxide, yttrium oxide and lanthanide oxides, which are added to the magnetic regulation catalyst as electron transfer intermediates to regulate the electron spin state and magnetic moment of the main magnetic component and the auxiliary magnetic component. The magnetic regulation catalyst is used for ammonia synthesis reaction, which comprises the following steps: 2g-5g of the catalyst is weighed and loaded in a fixed bed reactor; nitrogen and hydrogen are introduced for ammonia synthesis reaction, the nitrogen flow rate is 15-150mL / min, the hydrogen flow rate is 45-350mL / min, the nitrogen to hydrogen flow rate ratio is 1:2-1:3, and a heat field, a magnetic field, an electric field or a heat field and an electromagnetic field are simultaneously applied to the nitrogen, hydrogen and catalyst; the reaction temperature is 100-500℃, the pressure is 1-10MPa; the electromagnetic field has a voltage of 1-150kV, a current of 10-5000mA, a frequency of 10Hz-1MHz, and a magnetic field strength of 9mT-1T.

2. The magnetic regulated catalyst according to claim 1 for the catalytic conversion of ammonia-hydrogen energy sources, characterized in that, The catalyst further comprises an electron transfer promotion component, which is one or more than two combinations of lithium oxide, sodium oxide, potassium oxide, rubidium oxide, calcium oxide, cesium oxide and barium oxide.

3. The magnetic regulated catalyst according to claim 2 for the catalytic conversion of ammonia-hydrogen energy sources, characterized in that, The catalyst further comprises a structure strengthening component, which is one or more than two combinations of silicon oxide, magnesium oxide, aluminum oxide, chromium oxide, vanadium oxide and titanium oxide.

4. The magnetic regulated catalyst of claim 3 for the catalytic conversion of ammonia-hydrogen energy sources, characterized by, The proportion of the main magnetic component, the auxiliary magnetic component, the electron spin regulation component, the electron transfer promotion component and the structure strengthening component is 60-90wt%, 5-30wt%, 0.005-2wt%, 0.005-3wt% and 0.5-5wt%, respectively.

5. The magnetic regulated catalyst of claim 1 for the catalytic conversion of ammonia-hydrogen energy sources, characterized in that, The preparation method of the catalyst comprises the following steps: The catalyst raw material is ground; The ground raw material is ball milled at a speed of 200r / min-400r / min for 1-3h to realize mixing treatment of the raw material; The raw material is placed in a water-cooled copper mold and inert gas is filled; the raw material is preliminarily melted by an electric arc furnace, the arc current is 20A, and the melting time is 80s-100h; after the filler is completely melted, the current is increased, and the arc current is adjusted to 140A, and the melting is carried out for 80s-100h, and the arc rotates around the filler at a uniform speed during the melting; The melted raw material is cooled to room temperature at a speed of 10℃ / min-300℃ / min to obtain solid molten material; The solid molten material is crushed and sieved to obtain the catalyst.

6. The magnetic regulated catalyst of claim 1 for the catalytic conversion of ammonia-hydrogen energy sources, characterized in that, The application comprises: 2-5g of the catalyst is weighed and loaded in a fixed bed reactor; The reactor is pre-reduced by flowing hydrogen from an initial temperature of 18-22 °C to 190-210 °C over 35-45 min, held for 25-35 min, then raised to 490-510 °C over 145-155 min, held for 9.5-10.5 h, with a reaction pressure of 0.9-10 bar and a hydrogen flow of 100-1000 mL / min; The reactor is cooled to room temperature to obtain the pre-reduced catalyst.

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