A doped iron-based catalyst for normal-parahydrogen conversion and its batch production method and application

Abstract

The present invention discloses a doped iron-based catalyst for normal parahydrogen conversion and its batch production method and application. The preparation method comprises the following steps: adding iron salt and active metal salt to water to obtain a mixed metal salt solution; under agitation, flowing a strong alkaline solution into the mixed metal salt solution, carrying out coprecipitation reaction, adjusting pH to 9-11; continuing to stir after 20-30min, stopping stirring, aging for a period of time at room temperature, filter pressing, obtaining a filter cake, the filter cake is washed, dried, crushed, granulated, sieved, and obtained a doped iron-based catalyst. The preparation method is simple in process, safe, and has mild reaction conditions, and is suitable for industrial batch preparation, with a single batch production capacity of 5-50kg. The obtained doped iron-based catalyst particles have good uniformity and high mechanical strength, effectively reducing the catalyst bed flow resistance, while catalytic activity is higher, not easily deactivated, and the doped active metal is evenly attached to the surface of the catalyst, and the catalyst is suitable for normal parahydrogen conversion reaction in industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of preparation of para-hydrogen conversion catalysts, and more specifically to a doped iron-based catalyst for para-hydrogen conversion, a batch production method, and applications thereof. Background Art

[0002] Liquid hydrogen is a crucial component of the hydrogen energy industry. The exothermic para-hydrogen conversion process during its cooling and liquefaction can cause evaporation, significantly impacting its storage and transportation. To minimize hydrogen losses during liquefaction and reliquefaction energy consumption, and to maximize the safe storage period of liquid hydrogen, para-hydrogen conversion catalysts (OP catalysts) are required to accelerate para-hydrogen conversion. US data have reported on hydrated iron oxide catalysts, one of the most widely used OP catalysts due to their high activity and safety, but the specific process has not been disclosed.

[0003] Currently, there is little research in China on hydrated iron oxide catalysts for ortho-parahydrogen conversion reactions. Chinese Patent Publication No. CN114367288A discloses a ortho-parahydrogen conversion catalyst, its preparation method, and its application. In this method, a weakly alkaline precipitant is used to precipitate iron from an iron salt to produce an iron-based catalyst. While alkaline conditions are easily controlled, the weakly alkaline precipitant in the raw materials (e.g., ammonia water, ammonium carbonate, ammonium bicarbonate) is highly volatile under reaction conditions (20-80°C). The ammonia gas released during the reaction is harmful to the human body, causing poisoning through respiratory inhalation and other tissue lesions such as damage to the central nervous system. This method also produces both waste gas and wastewater, and the nitrogen content easily exceeds the standard, making it difficult to treat.

[0004] Chinese patent publication number CN113797928A discloses a method for preparing a catalyst for the conversion of liquid hydrogen to para-hydrogen. This method is a laboratory pilot-scale preparation method in which a metal ion-doped catalyst is prepared via a hydrothermal reaction. However, the hydrothermal reaction must be carried out in a sealed high-pressure reactor at 130°C-160°C and 0.35MPa-0.70MPa, posing certain safety risks and resulting in low yields, making it unsuitable for industrial production.

[0005] Chinese patent publication number CN 112044457 A discloses a supported n-parahydrogen conversion catalyst and its preparation method. The catalyst's raw materials include a support, a non-metallic compound, and a metal oxide. This method involves a double impregnation process to attach non-metallic ions such as phosphorus, chlorine, and fluorine to the inner and outer surfaces of the support, while also attaching iron, chromium, ruthenium, and other metals to the inner and outer surfaces of the non-metallic-modified support. However, there are issues with the active metal's tendency to detach and escape, and significant variability in catalyst activity between batches.

[0006] In order to realize the domestic large-scale production of para-hydrogen catalysts, it is urgently necessary to develop a preparation method for para-hydrogen conversion catalysts with high catalytic activity, stable catalytic activity, high mechanical strength, stable activity in multiple batches of production, and suitable for industrial batch production to meet actual application needs. Summary of the Invention

[0007] In view of the above drawbacks, the first object of the present invention is to provide a method for mass production of doped iron-based catalysts. This method is simple, safe, and has mild reaction conditions, and is suitable for industrial batch production, with a single batch production capacity of 5-50 kg.

[0008] A second object of the present invention is to provide a doped iron-based catalyst prepared using the aforementioned mass production method. This catalyst exhibits uniform particles, high mechanical strength, and effectively reduces the flow resistance of the catalyst bed. Furthermore, it exhibits high catalytic activity and is not susceptible to deactivation. The doped active metal is uniformly adhered to the catalyst surface, making it suitable for industrial production of normal-para-hydrogen conversion reactions.

[0009] The third object of the present invention is to provide a method for using the doped iron-based catalyst as described above in a para-hydrogen conversion reaction.

[0010] In order to achieve the above first purpose, the present invention adopts the following technical solutions:

[0011] The present invention discloses a method for batch production of a doped iron-based catalyst, comprising the following steps:

[0012] adding iron salt and active metal salt into water to obtain a mixed metal salt solution;

[0013] Under stirring conditions, a strong alkali solution is flowed into the mixed metal salt solution to carry out a coprecipitation reaction and adjust the pH to 9-11; stirring is continued for 20-30 minutes and then stopped, and the mixture is aged at room temperature for a period of time and filtered to obtain a filter cake. The filter cake is washed, dried, crushed, granulated, and sieved to obtain a doped iron-based catalyst.

[0014] Among the currently disclosed preparation processes for doped iron-based catalysts, most are based on small-scale laboratory tests. In the laboratory stage, there is no need to pay excessive attention to the severity of the preparation conditions (high temperature, high pressure), the treatment of wastewater and waste gas, the influence of mass transfer and heat transfer, the influence of catalyst particle size control on subsequent catalytic reactions, etc. Instead, it is only necessary to focus on the improvement of the catalyst in terms of activity and morphology. However, when industrial transformation is carried out, the preparation routes developed in the laboratory are usually less feasible and there is a problem of difficulty in industrial transformation. For example, the method of preparing doped iron-based catalysts by hydrothermal reaction in laboratory tests obviously cannot be directly transferred to industrial production. At the same time, the treatment of three wastes is also a key issue of concern in workshop production. Therefore, it is still difficult to develop a preparation method for doped iron-based catalysts suitable for industrial production.

[0015] The present invention is based on industrial production and adopts a co-precipitation method to prepare a doped iron-based catalyst. The process design of the method has the following considerations: 1) the co-precipitation method is used to prepare the doped iron-based catalyst. The preparation conditions are mild and can be carried out at room temperature, the temperature is easy to control, and the energy consumption is low; 2) a strong alkaline solution is used as a precipitant. Compared with a weak alkaline solution, it does not generate waste gas and will not cause harm to the human respiratory tract and nervous system as well as the atmospheric environment, thereby reducing the design investment of the production line for tail gas recovery and gas leakage prevention in industrial production; 3) the pH value at the precipitation endpoint is accurately controlled to reduce the impact of the strong alkaline precipitant on the catalytic performance and the amount of pure water used in the subsequent washing of the precipitate; 4) the temperature of the co-precipitation reaction and aging stage is controlled to be maintained at room temperature, thereby controlling the reaction rate; 5) the dried powder is further subjected to pulverization, granulation and sieving, which are essential steps for preparing the catalyst of the present invention. These steps can improve the uniformity and suitable particle size distribution of the catalyst particles, reduce the flow resistance of the catalyst bed, and at the same time, increase the mechanical strength of the catalyst to prevent the catalyst bed from pulverizing and causing device clogging during use.

[0016] Furthermore, the concentration of the iron salt in the mixed metal salt solution is 0.5-20 mol / L, and the ratio of the concentration of the active metal salt to the concentration of the iron salt is 0.005-0.30:1.

[0017] Furthermore, the active metal salt includes but is not limited to one or more of active metal nitrates, active metal sulfates and active metal chlorides.

[0018] Furthermore, the metal in the active metal salt includes but is not limited to one or more of Co, Ni, Ce and Al; illustratively, the active metal salt can be CoSO4·7H2O, Co(NO3)2·6H2O, CoCl2·6H2O, Ni(NO3)2·6H2O, NiSO4·7H2O, NiCl2·6H2O, Ce(NO3)3·6H2O, Ce2(SO4)3·8H2O, CeCl3·7H2O, Al(NO3)3·9H2O, Al2(SO4)3·16H2O, AlCl3·6H2O and the like.

[0019] In one embodiment, when adding the strong alkali solution, stirring should be turned on to enhance the mixing between the materials, so that the flowing strong alkali solution is fully in contact with the iron salt and the active metal salt and a precipitate is generated, which also facilitates more accurate collection of the pH value in the reaction system; after the pH reaches the target value, the addition of the strong alkali solution is stopped, and stirring is continued for 20-30 minutes, and then stirring is turned off and aged at room temperature to allow the precipitate to continue to grow, thereby reducing the influence of the stirring shear force on the product particle size.

[0020] Furthermore, in industrial production, the rate and time of addition of the strong alkali solution need to be controlled to achieve the purpose of controlling the co-precipitation reaction rate in the reactor, wherein the rate of addition of the strong alkali solution is 3.35-5.2 kg / min, and the addition time is controlled within 40-75 min.

[0021] In a specific embodiment, during the co-precipitation process, the reaction system will continuously release heat due to the reaction, and the temperature will rise significantly. In order to ensure that the temperature of the co-precipitation process is always at room temperature, the cold cycle should be opened in time to cool the reaction system to ensure that the reaction temperature does not change too much, which is conducive to uniform growth of the precipitate.

[0022] Furthermore, the aging time is 12-16 hours, and the aging process under static conditions is conducive to better growth of the precipitate.

[0023] In one embodiment, filter pressing is used for solid-liquid separation. Compared with traditional centrifuge filtration, it has a larger processing capacity. At the same time, it can fully wash all parts of the filter cake during washing, reducing the residual alkali salt and the generation of wastewater, and the washing efficiency is higher.

[0024] Furthermore, the drying conditions are first drying at 20-80° C. for 2-10 hours, and then drying at 100-150° C. for 0.5-16 hours.

[0025] Furthermore, the alkali used in the strong alkali solution is a strong base weak acid salt, including but not limited to one or more of potassium hydroxide, sodium hydroxide, sodium bicarbonate and sodium carbonate, and its mass concentration is 7%-30%.

[0026] Furthermore, in order to further reduce the impact of the strong alkaline precipitant on the catalyst and the amount of pure water used in the subsequent precipitate washing, the pH of the co-precipitation reaction should be controlled at 9-9.5. The pH value can be monitored by adding a pH monitoring device to the reaction tank to achieve precise control of the pH.

[0027] In order to achieve the above second purpose, the present invention adopts the following technical solutions:

[0028] The present invention discloses a doped iron-based catalyst for normal-parahydrogen conversion. The doped iron-based catalyst is prepared by the above-mentioned preparation method.

[0029] Furthermore, the doped iron-based catalyst is in the form of irregular particles, and the average crushing force of a single particle is 3-7N / particle. The higher single particle crushing force can keep the catalyst in a complete particle state during the ortho-parahydrogen conversion reaction, thereby preventing the catalyst bed from pulverizing.

[0030] Those skilled in the art will appreciate that the particle size of the doped iron-based catalyst affects the catalyst's accumulation state within the reaction apparatus and its contact state with the raw materials, thereby affecting the catalyst's catalytic activity. In one embodiment, the doped iron-based catalyst is sieved to a particle size of 10-120 mesh. Preferably, a particle size of 30-50 mesh results in a higher catalytic activity.

[0031] In order to achieve the third object, the present invention adopts the following technical solutions:

[0032] The present invention discloses an application of the doped iron-based catalyst in a para-hydrogen conversion reaction.

[0033] The application is also carried out in the context of industrial production, so the inventors have considered future practical applications in terms of the single-particle crushing force value and particle size of the catalyst. Specifically, in industrial production, since the ortho-parahydrogen conversion reaction requires continuous blowing of high-flow gas into the device, the catalyst will collide with the inner wall of the device when swept by the gas, so the mechanical strength of the catalyst should be improved; in addition, the particle size of the catalyst not only affects the contact between the catalyst and the reaction system, but also affects the accumulation state of the catalyst. This is not obvious in the small-scale test stage. In industrial production, particles that are too large or too small are not conducive to the reaction.

[0034] In one specific embodiment, in order to ensure that the doped iron-based catalyst can be better applied in the industrial production of normal-parahydrogen conversion, the average crushing force of a single doped iron-based catalyst should be no less than 3N / particle. At the same time, after the catalyst is fully activated, it is placed in a catalyst activity evaluation device and catalyzes the conversion of normal-parahydrogen into parahydrogen under the reaction conditions of 1.36atm&77K and 1200cc(H2) / min / cc(catalyst). The obtained parahydrogen content should be above 40%.

[0035] The beneficial effects of the present invention are as follows:

[0036] The present invention provides a method for preparing a doped iron-based catalyst suitable for industrial production. The method optimizes the process route and preparation condition parameters according to workshop production requirements, and ultimately prepares a doped iron-based catalyst with high catalytic activity, not easily deactivated, uniform particles, and high mechanical strength. The entire preparation process is simple and safe, and the reaction conditions are mild. It is suitable for industrial batch preparation, and the single batch production capacity reaches 5-50kg, which can meet actual application needs.

[0037] The prepared catalyst is doped with elements such as cobalt, nickel, cerium, and aluminum and is prepared by a co-precipitation method, which effectively reduces the flow resistance of the catalyst bed. Moreover, the uniform adhesion of the doped metal active substance on the catalyst surface makes the catalyst activity significantly improved compared with traditional hydrated iron oxide catalysts. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0039] Figure 1 The catalytic performance test result notification sheet of Example 5 is shown. DETAILED DESCRIPTION

[0040] In order to more clearly illustrate the present invention, the present invention is further described below in conjunction with preferred embodiments and drawings. Those skilled in the art should understand that the following specific description is illustrative rather than restrictive and should not be used to limit the scope of protection of the present invention.

[0041] Example 1 (workshop pilot program)

[0042] Prepare a precursor solution containing metal active substances by dissolving 50 kg of hydrated ferric nitrate and 1.8 kg of hydrated cobalt nitrate in 150 kg of water to prepare a mixed metal salt solution; prepare a sodium hydroxide solution with a mass fraction of 7.2%;

[0043] The invention adopts a co-precipitation method, wherein an alkali solution is added to a mixed metal salt solution under stirring at a rate of 3.35-5.2 kg / min, and the pH value of the system is adjusted to 9.12 within about 45-70 minutes. After stirring for 30 minutes, stirring is stopped, and the temperature of the reaction system is controlled to age at room temperature for 12 hours. After aging, the filter is pressed to obtain a filter cake, which is washed with pure water multiple times until the filtrate is neutral. The filter cake is dried in an industrial oven at 40°C for 6 hours and then at 110°C for 16 hours. After drying, it is crushed, granulated, and sieved to obtain a 30-50 mesh iron-based catalyst doped with cobalt.

[0044] After being fully activated, the catalyst was placed in a catalyst activity evaluation device at 77K and a certain space velocity. A gas chromatograph was used to collect data and measure the catalyst activity in the liquid nitrogen temperature zone at a certain space velocity.

[0045] The catalyst was tested for mechanical strength using a particle strength tester. Three groups of catalysts were taken, with 20-30 particles in each group. When the data was collected, the highest and lowest values ​​of each group were removed and the average value was calculated. The test results are summarized as follows:

[0046] Table 1 Catalytic activity and mechanical strength of cobalt-doped iron-based catalysts

[0047] Reaction conditions catalytic activity Average crushing force of single particle (30-50 mesh) <![CDATA[1.36 atm & 77 K, 1200 cc(H2) / min / cc(catalyst)]]> 41.84% parahydrogen content 3.38N / piece

[0048] Example 2 (workshop pilot program)

[0049] Prepare a precursor solution containing metal active substances by dissolving 50 kg of hydrated ferric nitrate and 1.8 kg of hydrated nickel nitrate in 150 kg of water to prepare a mixed metal salt solution; prepare a 7.0% by mass sodium carbonate solution;

[0050] The invention adopts a co-precipitation method, wherein an alkali solution is added to a mixed metal salt solution under stirring at a rate of 3.35-5.2 kg / min, and the pH value of the system is adjusted to 9.23 within about 50-70 minutes. The stirring is continued for 30 minutes and then stopped. The temperature of the reaction system is controlled to age at room temperature for 12 hours, and the system is filtered. After the aging is completed, the system is filtered to obtain a filter cake, which is washed with pure water multiple times until the filtrate is neutral. The filter cake is dried in an industrial oven at 40°C for 8 hours and then at 115°C for 16 hours. After drying, the system is crushed, granulated, and sieved to obtain a 30-50 mesh iron-based catalyst doped with nickel.

[0051] After being fully activated, the catalyst was placed in a catalyst activity evaluation device at 77K and a certain space velocity. A gas chromatograph was used to collect data and measure the catalyst activity in the liquid nitrogen temperature zone at a certain space velocity.

[0052] The catalyst was tested for mechanical strength using a particle strength tester. Three groups of catalysts were taken, with 20-30 particles in each group. When the data was collected, the highest and lowest values ​​of each group were removed and the average value was calculated. The test results are summarized as follows:

[0053] Table 2 Catalytic activity and mechanical strength of nickel-doped iron-based catalysts

[0054] Reaction conditions catalytic activity Average crushing force of single particle (30-50 mesh) <![CDATA[1.36 atm & 77 K, 1200 cc(H2) / min / cc(catalyst)]]> 40.27% parahydrogen content 3.27N / piece

[0055] Example 3 (workshop pilot program)

[0056] Prepare a precursor solution containing metal active substances by dissolving 50 kg of hydrated ferric nitrate and 2.69 kg of hydrated cerium nitrate in 150 kg of water to prepare a mixed metal salt solution; prepare a 7.1% sodium bicarbonate solution;

[0057] The invention adopts a co-precipitation method, wherein an alkali solution is added to a mixed metal salt solution under stirring at a rate of 3.35-5.2 kg / min, and the pH value of the system is adjusted to 9.53 within about 50-75 minutes. After stirring for 30 minutes, stirring is stopped, and the temperature of the reaction system is controlled to age at room temperature for 12 hours. After aging, the system is filtered to obtain a filter cake, which is washed with pure water multiple times until the filtrate is neutral. The filter cake is dried in an industrial oven at 40°C for 7 hours and then at 150°C for 16 hours. After drying, the filter cake is crushed, granulated, and sieved to obtain a 30-50 mesh iron-based catalyst doped with cerium.

[0058] After being fully activated, the catalyst was placed in a catalyst activity evaluation device at 77K and a certain space velocity. A gas chromatograph was used to collect data and measure the catalyst activity in the liquid nitrogen temperature zone at a certain space velocity.

[0059] The catalyst was tested for mechanical strength using a particle strength tester. Three groups of catalysts were taken, with 20-30 particles in each group. When the data was collected, the highest and lowest values ​​of each group were removed and the average value was calculated. The test results are summarized as follows:

[0060] Table 3 Catalytic activity and mechanical strength of cerium-doped iron-based catalysts

[0061] Reaction conditions catalytic activity Average crushing force of single particle (30-50 mesh) <![CDATA[1.36 atm & 77 K, 1200 cc(H2) / min / cc(catalyst)]]> 43.94% parahydrogen content 3.25N / piece

[0062] Example 4 (workshop pilot program)

[0063] Prepare a precursor solution containing metal active substances by dissolving 50 kg of hydrated ferric nitrate and 9.28 kg of hydrated aluminum nitrate in 150 kg of water to prepare a mixed metal salt solution; prepare an 8.5% by mass sodium hydroxide solution;

[0064] The invention adopts a co-precipitation method, wherein an alkali solution is added to a mixed metal salt solution under stirring at a rate of 3.35-5.2 kg / min, and the pH value of the system is adjusted to 9.14 within about 45-65 minutes. After stirring for 30 minutes, stirring is stopped, and the temperature of the reaction system is controlled to age at room temperature for 12 hours. After aging, the filter is pressed to obtain a filter cake, which is washed with pure water multiple times until the filtrate is neutral. The filter cake is dried in an industrial oven at 50°C for 6 hours and then at 110°C for 16 hours. After drying, it is crushed, granulated, and sieved to obtain a 30-50 mesh iron-based catalyst doped with aluminum.

[0065] After being fully activated, the catalyst was placed in a catalyst activity evaluation device at 77K and a certain space velocity. A gas chromatograph was used to collect data and measure the catalyst activity in the liquid nitrogen temperature zone at a certain space velocity.

[0066] The catalyst was tested for mechanical strength using a particle strength tester. Three groups of catalysts were taken, with 20-30 particles in each group. When the data was collected, the highest and lowest values ​​of each group were removed and the average value was calculated. The test results are summarized as follows:

[0067] Table 4 Catalytic activity and mechanical strength of aluminum-doped iron-based catalysts

[0068] Reaction conditions catalytic activity Average crushing force of single particle (30-50 mesh) <![CDATA[1.36 atm & 77 K, 1200 cc(H2) / min / cc(catalyst)]]> 44.8% parahydrogen content 3.45N / piece

[0069] Example 5 (workshop pilot program)

[0070] Prepare a precursor solution containing metal active substances by dissolving 50 kg of hydrated ferric nitrate, 2.68 kg of hydrated cerium nitrate, and 9.28 kg of hydrated aluminum nitrate in 150 kg of water to prepare a mixed metal salt solution; prepare a 9% by mass sodium hydroxide solution;

[0071] The invention adopts the co-precipitation method, and adds the alkali solution to the mixed metal salt solution under stirring at a rate of 3.35-5.2 kg / min. The pH value of the system is adjusted to 9.02 within about 45-60 minutes, and stirring is stopped after continuing for 30 minutes. The temperature of the reaction system is controlled to age at room temperature for 12 hours. After aging, the filter is pressed to obtain a filter cake, which is washed with pure water many times until the filtrate is neutral. The filter cake is dried in an industrial oven at 40°C for 6 hours and then at 110°C for 16 hours. After drying, it is crushed, granulated, and sieved to obtain a 30-50 mesh iron-based catalyst doped with cerium and aluminum elements.

[0072] After being fully activated, the catalyst was placed in a catalyst activity evaluation device at 77K and a certain space velocity. A gas chromatograph was used to collect data and measure the catalyst activity in the liquid nitrogen temperature zone at a certain space velocity.

[0073] The catalyst was tested for mechanical strength using a particle strength tester. Three groups of catalysts were taken, with 20-30 particles in each group. When the data was collected, the highest and lowest values ​​of each group were removed and the average value was calculated. The test results are summarized as follows:

[0074] Table 5 Catalytic activity and mechanical strength of cerium-aluminum doped iron-based catalysts

[0075] Reaction conditions catalytic activity Average crushing force of single particle (30-50 mesh) <![CDATA[1.36 atm & 77 K, 1200 cc(H2) / min / cc(catalyst)]]> 45.54% parahydrogen content 3.5N / piece

[0076] Example 6 (workshop pilot program)

[0077] Prepare a precursor solution containing metal active substances by dissolving 50 kg of hydrated ferric nitrate, 1.8 kg of hydrated cobalt nitrate, and 9.28 kg of aluminum nitrate in 150 kg of water to prepare a mixed metal salt solution; prepare an 8.9% by mass sodium hydroxide solution;

[0078] The invention adopts the co-precipitation method, and adds the alkali solution to the mixed metal salt solution under stirring at a flow rate of 3.35-5.2 kg / min. The pH value of the system is adjusted to 9.10 in about 45-60 minutes, and stirring is stopped after continuing for 30 minutes. The temperature of the reaction system is controlled to age at room temperature for 12 hours. After aging, the filter is pressed to obtain a filter cake, which is washed with pure water many times until the filtrate is neutral. The filter cake is dried in an industrial oven at 45°C for 6 hours, and then dried at 110°C for 16 hours. After drying, it is crushed, granulated, and sieved to obtain a 30-50 mesh iron-based catalyst doped with cobalt and aluminum elements.

[0079] After being fully activated, the catalyst was placed in a catalyst activity evaluation device at 77K and a certain space velocity. A gas chromatograph was used to collect data and measure the catalyst activity in the liquid nitrogen temperature zone at a certain space velocity.

[0080] The catalyst was tested for mechanical strength using a particle strength tester. Three groups of catalysts were taken, with 20-30 particles in each group. When the data was collected, the highest and lowest values ​​of each group were removed and the average value was calculated. The test results are summarized as follows:

[0081] Table 6 Catalytic activity and mechanical strength of cobalt-aluminum doped iron-based catalysts

[0082] Reaction conditions catalytic activity Average crushing force of single particle (30-50 mesh) <![CDATA[1.36 atm & 77 K, 1200 cc(H2) / min / cc(catalyst)]]> 45.36% parahydrogen content 3.26N / piece

[0083] Comparative Example 1 (Workshop Pilot Scheme)

[0084] Prepare a precursor solution containing metal active substances by dissolving 50 kg of hydrated ferric nitrate in 150 kg of water; prepare a sodium hydroxide solution with a mass fraction of 7.3%;

[0085] Under stirring conditions, the alkali solution is added to the ferric nitrate solution at a flow rate of 3.35-5.2 kg / min, and the pH of the system is adjusted to 9.25 within about 45-70 minutes. After continuing stirring for 30 minutes, stirring is stopped, and the temperature of the reaction system is controlled to age at room temperature for 12 hours. After aging, the filter is pressed to obtain a filter cake, which is washed with pure water multiple times until the filtrate is neutral. The filter cake is dried in an industrial oven at 40°C for 6 hours, then dried at 110°C for 16 hours, and then crushed, granulated, and sieved to obtain a 30-50 mesh iron-based catalyst.

[0086] After being fully activated, the catalyst was placed in a catalyst activity evaluation device at 77K and a certain space velocity. A gas chromatograph was used to collect data and measure the catalyst activity in the liquid nitrogen temperature zone at a certain space velocity.

[0087] The catalyst was tested for mechanical strength using a particle strength tester. Three groups of catalysts were taken, with 20-30 particles in each group. When the data was collected, the highest and lowest values ​​of each group were removed and the average value was calculated. The test results are summarized as follows:

[0088] Table 7 Catalytic activity and mechanical strength of iron-based catalysts

[0089] Reaction conditions catalytic activity Average crushing force of single particle (30-50 mesh) <![CDATA[1.36 atm & 77 K, 1200 cc(H2) / min / cc(catalyst)]]> 36.45% parahydrogen content 2.91N / piece

[0090] Comparative Example 2 (laboratory test plan)

[0091] Prepare a precursor solution containing metal active substances by dissolving 50g of hydrated ferric nitrate and 1.8g of hydrated nickel nitrate in 150g of water to prepare a mixed metal salt solution; prepare a sodium hydroxide solution with a mass fraction of 10%;

[0092] Under stirring conditions, the alkali solution is added to the ferric nitrate solution at a flow rate of 10 g / min, and the pH of the system is adjusted to 11 in about 20-30 minutes. After continuing stirring for 30 minutes, stirring is stopped, and the temperature of the reaction system is controlled to age at room temperature for 12 hours. After aging, it is filtered to obtain a filter cake, and the filter cake is washed with pure water multiple times until the filtrate is neutral. The filter cake is dried in an oven at 80°C for 4 hours, and then dried at 130°C for 15 hours. After drying, it is crushed, granulated, and sieved to obtain a 20-40 mesh iron-based catalyst doped with nickel.

[0093] After being fully activated, the catalyst was placed in a catalyst activity evaluation device at 77K and a certain space velocity. A gas chromatograph was used to collect data and measure the catalyst activity in the liquid nitrogen temperature zone at a certain space velocity.

[0094] The catalyst was tested for mechanical strength using a particle strength tester. Three groups of catalysts were taken, with 20-30 particles in each group. When the data was collected, the highest and lowest values ​​of each group were removed and the average value was calculated. The test results are summarized as follows:

[0095] Table 8 Catalytic activity and mechanical strength of iron-based catalysts

[0096] Reaction conditions catalytic activity Average crushing force of single particle (20-40 mesh) <![CDATA[1.36 atm & 77 K, 1200 cc (H2) / min / cc (catalyst)]]> 42.65% parahydrogen content 3.71N / piece

[0097] Comparative Example 3 (Workshop Pilot Scheme)

[0098] Prepare a precursor solution containing metal active substances by dissolving 50 kg of hydrated ferric nitrate and 1.8 kg of hydrated nickel nitrate in 150 kg of water to prepare a mixed metal salt solution; prepare a 10% by mass sodium carbonate solution;

[0099] The invention adopts the co-precipitation method, and adds the alkali solution to the mixed metal salt solution under stirring at a flow rate of 10 kg / min. The pH value of the system is adjusted to 11 in about 20-30 minutes, and stirring is stopped after continuing for 30 minutes. The temperature of the reaction system is controlled to age at room temperature for 12 hours, and filter press is performed. After the aging is completed, filter press is performed to obtain a filter cake, and the filter cake is washed with pure water many times until the filtrate is neutral. The filter cake is dried in an industrial oven at 80°C for 4 hours, and then dried at 130°C for 15 hours. After drying, it is crushed, granulated, and sieved to obtain a 20-40 mesh iron-based catalyst doped with nickel element.

[0100] After being fully activated, the catalyst was placed in a catalyst activity evaluation device at 77K and a certain space velocity. A gas chromatograph was used to collect data and measure the catalyst activity in the liquid nitrogen temperature zone at a certain space velocity.

[0101] The catalyst was tested for mechanical strength using a particle strength tester. Three groups of catalysts were taken, with 20-30 particles in each group. When the data was collected, the highest and lowest values ​​of each group were removed and the average value was calculated. The test results are summarized as follows:

[0102] Table 9 Catalytic activity and mechanical strength of nickel-doped iron-based catalysts

[0103] Reaction conditions catalytic activity Average crushing force of single particle (20-40 mesh) <![CDATA[1.36 atm & 77 K, 1200 cc(H2) / min / cc(catalyst)]]> 32.78% parahydrogen content 3.57N / piece

[0104] Comparative Example 4 (Workshop Pilot Scheme)

[0105] Prepare a precursor solution containing metal active substances by dissolving 50 kg of hydrated ferric nitrate and 1.8 kg of hydrated nickel nitrate in 150 kg of water to prepare a mixed metal salt solution; prepare a 10% by mass sodium carbonate solution;

[0106] The invention adopts the co-precipitation method, and adds the alkali solution to the mixed metal salt solution under stirring at a flow rate of 10 kg / min. The pH value of the system is adjusted to 11 in about 20-30 minutes, and stirring is stopped after continuing for 30 minutes. The temperature of the reaction system is controlled to age at room temperature for 12 hours, and filter press is performed. After the aging is completed, filter press is performed to obtain a filter cake, and the filter cake is washed with pure water many times until the filtrate is neutral. The filter cake is dried in an industrial oven at 80°C for 4 hours, and then dried at 130°C for 15 hours. After drying, it is crushed, granulated, and sieved to obtain a 30-50 mesh iron-based catalyst doped with nickel element.

[0107] After being fully activated, the catalyst was placed in a catalyst activity evaluation device at 77K and a certain space velocity. A gas chromatograph was used to collect data and measure the catalyst activity in the liquid nitrogen temperature zone at a certain space velocity.

[0108] The catalyst was tested for mechanical strength using a particle strength tester. Three groups of catalysts were taken, with 20-30 particles in each group. When the data was collected, the highest and lowest values ​​of each group were removed and the average value was calculated. The test results are summarized as follows:

[0109] Table 10 Catalytic activity and mechanical strength of nickel-doped iron-based catalysts

[0110] Reaction conditions catalytic activity Average crushing force of single particle (30-50 mesh) <![CDATA[1.36 atm & 77 K, 1200 cc(H2) / min / cc(catalyst)]]> 34.45% parahydrogen content 3.01N / piece

[0111] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for batch production of a doped iron-based catalyst, characterized in that: The steps include: Prepare a precursor solution containing metal active substances by dissolving 50 kg of hydrated ferric nitrate, 2.68 kg of hydrated cerium nitrate, and 9.28 kg of hydrated aluminum nitrate in 150 kg of water to prepare a mixed metal salt solution; prepare a 9% by mass sodium hydroxide solution; The invention adopts a co-precipitation method, wherein an alkali solution is added to a mixed metal salt solution under stirring at a rate of 3.35-5.2 kg / min, and the pH value of the system is adjusted to 9.02 within 45-60 minutes. The stirring is continued for 30 minutes and then stopped. The temperature of the reaction system is controlled to age at room temperature for 12 hours. After the aging is completed, the filter is pressed to obtain a filter cake, which is washed with pure water many times until the filtrate is neutral. The filter cake is dried in an industrial oven at 40°C for 6 hours and then at 110°C for 16 hours. After drying, the filter cake is crushed, granulated, and sieved to obtain a 30-50 mesh iron-based catalyst doped with cerium and aluminum elements.

2. A method for batch production of a doped iron-based catalyst, characterized in that: The steps include: Prepare a precursor solution containing metal active substances by dissolving 50 kg of hydrated ferric nitrate, 1.8 kg of hydrated cobalt nitrate, and 9.28 kg of aluminum nitrate in 150 kg of water to prepare a mixed metal salt solution; prepare an 8.9% by mass sodium hydroxide solution; The method adopts the co-precipitation method. Under stirring conditions, the alkali solution is added to the mixed metal salt solution at a flow rate of 3.35-5.2 kg / min. The pH value of the system is adjusted to 9.10 in 45-60 minutes. The stirring is stopped after continuing for 30 minutes. The temperature of the reaction system is controlled to age at room temperature for 12 hours. After the aging is completed, the filter is pressed to obtain a filter cake. The filter cake is washed with pure water many times until the filtrate is neutral. The filter cake is dried in an industrial oven at 45°C for 6 hours and then at 110°C for 16 hours. After drying, it is crushed, granulated and sieved to obtain a 30-50 mesh iron-based catalyst doped with cobalt and aluminum elements.

3. A doped iron-based catalyst for conversion of normal and para-hydrogen, characterized in that: The doped iron-based catalyst is prepared by the batch production method according to claim 1 or 2; The doped iron-based catalyst is in the form of irregular particles, and the average crushing force of a single particle is 3-7N / particle; The particle size of the doped iron-based catalyst is 30-50 meshes.

4. Use of the doped iron-based catalyst as claimed in claim 3 in a para-hydrogen conversion reaction.

Images