Preparation method of high-temperature methanol water reforming hydrogen copper-manganese-rare earth catalyst

Abstract

This invention belongs to the field of catalyst technology, specifically disclosing a method for preparing a copper-manganese-rare earth catalyst for high-temperature methanol-water reforming to produce hydrogen. The catalyst preparation method includes the following steps: (1) mixing copper compounds, manganese carbonate, rare earth elements, and alkali metal compounds in a specific mass percentage and then ball-milling to obtain a solid powder; (2) mixing the solid powder with a molding aid and then extruding it into strip-shaped catalysts; (3) drying the strip-shaped catalysts in an oven; and (4) transferring the dried strip-shaped catalysts to a muffle furnace for calcination. The catalyst prepared by this invention has a diameter of up to 2-5 mm, a mechanical strength >400 N / cm, and remains stable at a high temperature of 400℃. It is suitable for small and medium-sized hydrogen production plants, and can improve methanol conversion and reduce the CO concentration in the product gas during hydrogen production.

Description

[Technical Field]

[0001] This invention relates to the field of catalyst technology, and in particular to a method for preparing a high-temperature methanol-water reforming copper-manganese rare earth catalyst for hydrogen production. [Background Technology]

[0002] Hydrogen energy, as an important clean energy source, has received increasing attention in recent years. The hydrogen energy industry chain mainly focuses on preparation, storage, and application, with preparation being fundamental. There are many traditional methods for hydrogen production, such as water electrolysis, natural gas production, and coal production, but these methods suffer from high investment costs, limited raw material reserves, or high electricity consumption, limiting their development potential. In contrast, methanol reforming for hydrogen production, due to its abundant raw materials, ease of storage and transportation, low energy consumption, and high hydrogen yield, is gradually becoming one of the key technologies for development in the hydrogen production field.

[0003] The key to methanol reforming for hydrogen production lies in the catalyst. Currently, most research focuses on copper-zinc-aluminum catalysts, but these catalysts are only suitable for environments with reaction temperatures of 230–280°C, and are not suitable for the high-temperature environments of 350–450°C required for small mobile hydrogen production equipment and fuel cells. To develop high-temperature methanol reforming hydrogen production catalysts, researchers have modified copper catalysts. For example, Majid Taghizadeh (Int. J. Hydrogen Energy 43, 10926–10937 (2018)) found that the incorporation of cerium oxide and the use of surfactant-assisted impregnation methods can effectively control the size of copper particles and improve the uniform distribution of metal species. However, this methanol reforming hydrogen production catalyst is only suitable for reaction at 300℃ and cannot be used in high-temperature methanol reforming hydrogen production systems. On the other hand, Yasuyuki Matsumura (Journal of Power Sources, 272 (2014) 961-969) found that Y2O3 and In2O3 modified CnZn / ZrO2 catalysts can maintain stability for 5300h at 400℃, which is a long stability time. However, this catalyst cannot be prepared into small-particle-size catalysts of 1-3mm after being pressed into tablets, which limits its use in small mobile methanol hydrogen production systems. Chinese invention patent CN202111663665.7 discloses the use of a high-temperature self-activated nano-cuprous oxide-zinc oxide composite catalyst for methanol steam reforming to produce hydrogen. Using this catalyst eliminates the need for a hydrogen pre-reduction process, resulting in lower costs and greater safety. It also boasts high hydrogen production efficiency, high methanol conversion rate, and long-term stability at temperatures above 500°C. However, its byproduct, carbon monoxide, has a high content, making it unsuitable for mobile methanol reforming hydrogen production systems. Furthermore, this technology struggles to obtain catalysts with small particle sizes of 1-3 mm, thus limiting its application range. [Summary of the Invention]

[0004] In view of the above, it is necessary to provide a method for preparing a copper-manganese rare earth catalyst for high-temperature methanol-water reforming to produce hydrogen. The copper-manganese rare earth catalyst prepared by this invention can reach a diameter of 2-5 mm, has a mechanical strength >400 N / cm, remains stable at a high temperature of 400℃, exhibits high mechanical strength, good catalytic performance, good high-temperature thermal resistance, and low cost, and produces a product gas with extremely low CO concentration. It is suitable for high-temperature methanol-water steam reforming to produce hydrogen at 350-450℃, and is applicable to small and medium-sized hydrogen production plants, especially suitable for hydrogen production capacities less than 1000 m³ / h. 3 A mobile methanol reforming hydrogen production system with a capacity of [number] hours.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for preparing a copper-manganese rare earth catalyst for high-temperature methanol-water reforming to hydrogen production includes the following steps:

[0007] (1) A solid mixture is prepared by mixing four components—copper compound, manganese carbonate, rare earth element, and alkali metal compound—at a mass percentage ratio of 60-70%:15-20%:1-5%:5-15%, with the sum of the mass percentages of the four components being 100%. The solid mixture is then added to a polytetrafluoroethylene ball milling jar containing zirconia grinding beads, and the jar is placed in a ball mill and milled at a speed of 150-250 r / min for 1-2 hours to obtain a solid powder with a particle size of 200-300 mesh. The copper compound is a mixture of copper aluminate and zinc chlorite; the rare earth element is yttrium oxide and / or praseodymium oxide; and the alkali metal compound is a mixture of magnesium hydroxide and calcium hydroxide.

[0008] (2) Add molding aid to the above solid powder, knead for 30 minutes, and then put it into an extruder for extrusion to obtain a strip catalyst with a diameter of 2-5 mm; the molding aid includes ammonium bicarbonate, silica sol and water;

[0009] (3) The obtained strip catalyst was placed in an oven and dried at 40°C for 12 hours;

[0010] (4) The dried strip catalyst is transferred to a muffle furnace and calcined in an air atmosphere at 350-450℃ for 4-6 hours. After cooling, it is cut into small segments of 3-8 mm to obtain the methanol-water reforming hydrogen production copper-manganese rare earth catalyst.

[0011] Furthermore, in step (1), the mass ratio of copper aluminate to copper zinc ore is 2:1.

[0012] Furthermore, in step (1), the copper aluminate is spinel phase copper aluminate.

[0013] Furthermore, the preparation method of the spinel phase copper aluminate is as follows: according to the Cu / Al molar ratio of 1:2, pseudoboehmite is repeatedly impregnated in copper nitrate solution. After impregnation, the pseudoboehmite is dried, uniformly ball-milled for 1 hour, and then placed in a muffle furnace. The temperature is raised to 950°C at a rate of 2°C / min and then cooled to obtain the spinel phase copper aluminate.

[0014] Furthermore, the preparation method of the green copper-zinc ore is as follows: a suspension of copper hydroxide, zinc hydroxide and sodium carbonate is placed in a crystallization reactor at a Cu / Zn molar ratio of 2:3, and a hydrothermal synthesis reaction is carried out at 150°C. Then, the mixture is filtered, washed with water and dried to obtain the green copper-zinc ore.

[0015] Furthermore, the green copper-zinc ore is (Cu 0.4 Zn 0.6 )2(OH)2CO3、(Cu 0.3 Zn 0.7 )2(OH)2CO3、(Cu 0.2 Zn 0.8 )2(OH)2CO3 and (Cu 0.1 Zn 0.9 At least one of )2(OH)2CO3.

[0016] Furthermore, in step (1), the molar ratio of Mg / Ca in the mixture of magnesium hydroxide and calcium hydroxide is 0.2-0.5:1.

[0017] Furthermore, in step (1), the mass ratio of the solid mixture to the zirconia grinding beads is 1:3-5.

[0018] Furthermore, in step (2), the mass ratio of the ammonium bicarbonate, the silica sol, and the water is 0.4:0.2:1.

[0019] Furthermore, in step (2), the mass ratio of the molding aid to the solid powder is 0.3-0.5.

[0020] The present invention has the following beneficial effects:

[0021] 1. The copper-manganese rare earth catalyst of this invention uses a mixture of spinel-phase copper aluminate and copper zinc ore as the copper source. The spinel-phase copper aluminate is a typical high-temperature resistant copper phase, and its spinel structure effectively inhibits copper grain growth at high temperatures. Meanwhile, copper zinc ore can form a CuO-ZnO composite porous structure at a certain temperature, exhibiting good structural stability and increasing the specific surface area of ​​the active phase. Furthermore, rare earth elements and manganese can synergistically catalyze the active phase, improving catalytic performance. The presence of alkali metals can enhance the efficiency of the water-CO conversion reaction and reduce the CO concentration in the product gas. In summary, the copper-manganese rare earth catalyst of this invention overcomes the shortcomings of traditional Cu-based catalysts, such as poor stability and high CO concentration in the product during methanol-water reforming hydrogen production at high temperatures. Its reaction temperature can reach 350-450℃, and it can operate at high temperatures for extended periods. When the catalyst of this invention is used in the methanol-water reforming hydrogen production reaction, the methanol conversion rate is as high as 98.3% after continuous operation for 360 hours at a reaction temperature of 400°C, and the CO concentration in the product gas can be as low as 0.3%.

[0022] 2. This invention, through the mixing of solid powder and molding aids, enables the production of small-diameter strip-shaped copper-manganese rare earth catalysts with a diameter of 2-5 mm via extrusion molding. These catalysts possess high mechanical strength, with a radial strength >400 N / cm, superior to conventional cylindrical (>200 N / cm) and spherical (>140 N / cm) commercial high-temperature methanol reforming hydrogen production catalysts. This meets the needs of small and medium-sized methanol reforming hydrogen production equipment, especially for hydrogen production capacities less than 1000 m³ / min. 3 The need for small-particle-size catalysts in methanol reforming hydrogen production systems with a capacity of [number] h. [Attached Image Description]

[0023] Figure 1 The figures show the XRD patterns of the catalysts prepared in Examples 1-10 of this invention. In the figures, ● represents the diffraction characteristic peak of CuO, and ■ represents the diffraction characteristic peak of CuAl2O4.

[0024] Figure 2 The image shows an elemental scanning electron microscope (SEM) image of the catalyst prepared in Example 9 of this invention. In the image, A is an HRSEM image of the catalyst cross-section, B is a further elemental scanning image of Cu, C is an elemental scanning image of Zn, and D is an elemental scanning image of Mn.

[0025] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention.

Detailed Implementation Methods

[0026] This invention provides a method for preparing a copper-manganese rare earth catalyst for high-temperature methanol-water reforming to hydrogen production, comprising the following steps:

[0027] (1) A solid mixture is prepared by mixing four components, namely copper compound, manganese carbonate, rare earth and alkali metal compound, in a mass percentage ratio of 60-70%:15-20%:1-5%:5-15%, and the sum of the mass percentages of the four components is 100%. The solid mixture is added to a polytetrafluoroethylene ball milling jar containing zirconia grinding beads, and the ball milling jar is placed in a ball mill and ball milled at a speed of 150-250 r / min for 1-2 h to obtain a solid powder with a particle size of 200-300 mesh. The copper compound is a mixture of copper aluminate and zirconia ore, that is, it is prepared by mixing, grinding and sieving copper aluminate and zirconia ore. The rare earth is yttrium oxide and / or praseodymium oxide. The alkali metal compound is a mixture of magnesium hydroxide and calcium hydroxide. Rare earth and manganese can produce a synergistic catalytic effect with the active phase to improve the catalytic performance. The presence of alkali metal can improve the efficiency of the water-CO conversion reaction and reduce the CO content in the product gas.

[0028] (2) Add molding aid to the above solid powder, knead for 30 minutes, and then put it into an extruder for extrusion to obtain a strip catalyst with a diameter of 2-5 mm; the molding aid includes ammonium bicarbonate, silica sol and water;

[0029] (3) The obtained strip catalyst was placed in an oven and dried at 40°C for 12 hours;

[0030] (4) The dried strip catalyst is transferred to a muffle furnace and calcined in an air atmosphere at 350-450℃ for 4-6 hours. After cooling, it is cut into small segments of 3-8 mm to obtain the strip-shaped methanol reforming to hydrogen copper manganese rare earth catalyst.

[0031] In step (1), the rotational speed of the ball mill can be 150 r / min, 200 r / min, 230 r / min, or 250 r / min in actual operation, as long as it is within the range of 150 to 250 r / min. The ball milling time can be 1 hour, 1.5 hours, 1.8 hours, or 2 hours.

[0032] In step (4), the roasting temperature can be 350℃, 380℃, 400℃ or 450℃, etc., and the roasting time can be 4h, 4.5h, 5h or 6h, etc.

[0033] This invention enables the production of small-particle-size strip-shaped copper-manganese rare earth catalysts with a diameter of 2-5 mm by mixing solid powder and molding aids and using extrusion molding. The catalyst has the advantages of high mechanical strength, good catalytic performance, good high-temperature thermal performance, and low cost.

[0034] In step (1) of this invention, the preferred mass ratio of copper aluminate to copper zinc ore is 2:1, and the preferred copper aluminate is spinel-phase copper aluminate (CuAl2O4). Spinel-phase copper aluminate is a typical high-temperature resistant copper phase. At high temperatures, this spinel structure can effectively prevent the growth of copper grains, thereby avoiding a decrease in catalyst activity.

[0035] In step (1) of the present invention, the preparation method of the spinel phase copper aluminate is as follows: according to the Cu / Al molar ratio of 1:2, the pseudoboehmite is repeatedly impregnated in copper nitrate solution. After impregnation, the pseudoboehmite is dried, uniformly ball-milled for 1 hour, and then placed in a muffle furnace. The temperature is raised to 950°C at a rate of 2°C / min and then cooled to obtain the spinel phase copper aluminate.

[0036] The preparation method of the green copper-zinc ore is as follows: A suspension of copper hydroxide, zinc hydroxide, and sodium carbonate is placed in a crystallization reactor at a Cu / Zn molar ratio of 2:3, and a hydrothermal synthesis reaction is carried out at 150°C. The mixture is then filtered, washed with water, and dried to obtain the green copper-zinc ore. The green copper-zinc ore product prepared by the above method is (Cu... 0.4 Zn 0.6 )2(OH)2CO3、(Cu 0.3 Zn 0.7 )2(OH)2CO3、(Cu 0.2 Zn 0.8 )2(OH)2CO3 and (Cu 0.1 Zn 0.9 The single pure substance or a mixture of two or more substances in 2(OH)2CO3. Therefore, the resulting green copper-zinc ore is (Cu 0.4 Zn 0.6 )2(OH)2CO3、(Cu 0.3 Zn 0.7 )2(OH)2CO3、(Cu 0.2 Zn 0.8 )2(OH)2CO3 and (Cu 0.1 Zn 0.9 At least one of 2(OH)2CO3. The green copper-zinc ore can form a CuO-ZnO composite structure at a certain temperature, which not only improves the dispersibility of the active phase but also enhances the stability of the catalyst.

[0037] In a preferred embodiment of the present invention, the green copper-zinc ore is preferably (Cu 0.4 Zn 0.6 )2(OH)2CO3.

[0038] In step (1) of the present invention, preferably, the molar ratio of Mg / Ca in the mixture of magnesium hydroxide and calcium hydroxide is 0.2-0.5:1.

[0039] In step (1) of the present invention, the mass ratio of the solid mixture to the zirconia grinding beads is preferably 1:3-5, and more preferably 1:4.

[0040] In step (2) of the present invention, preferably, the mass ratio of the molding aid to the solid powder is 0.3-0.5; the mass ratio of the ammonium bicarbonate, the silica sol and the water is 0.4:0.2:1, that is, the molding aid is mainly obtained by uniformly mixing ammonium bicarbonate, the silica sol and the water.

[0041] The catalyst prepared by the above method is suitable for high-temperature methanol reforming hydrogen production processes. When used for hydrogen production of less than 1000 m³ / h, the catalyst prepared by the above method is suitable for applications involving hydrogen production. 3 A methanol reforming hydrogen production system with a capacity of [number] h operates under the following process conditions: reaction temperature 350-450℃, pressure 0.2-3 MPa, and volume hourly space velocity (VHSV) 0.5-3.0 h⁻¹. -1 In the CH3OH / H2O raw material reaction solution, the mass fraction of CH3OH is 45-55%.

[0042] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0043] Example 1

[0044] 1. Preparation of copper compounds

[0045] (1) Preparation of spinel phase copper aluminate

[0046] Weigh 48.6g of copper nitrate nonahydrate, add an appropriate amount of water and stir to dissolve. Adjust the pH of the solution to 7 by adding dilute ammonia dropwise, then add distilled water to adjust the solution volume to 252ml. After thorough stirring, obtain a copper nitrate solution with a copper concentration of 0.8mol / L. Weigh 31.38g of boehmite, add 63ml of the above copper nitrate solution for impregnation, and dry at 40℃ for 5h after impregnation. Repeat this process three times. Weigh 36g of the impregnated and dried boehmite and 150g of zirconia grinding beads into a ball mill jar and ball mill at 200r / min for 1h. After ball milling, place the boehmite in a muffle furnace and heat to 950℃ at 2℃ / min in an air atmosphere. After cooling, obtain CuAl2O4 with a spinel phase.

[0047] (2) Preparation of green copper-zinc ore

[0048] 9.75 g of copper hydroxide and 14.90 g of zinc hydroxide were weighed into a polytetrafluoroethylene-lined container, and 60 ml of an aqueous solution prepared with 21.20 g of sodium carbonate was added and stirred thoroughly. After adding a stirring rotor, the container was sealed in a crystallization reactor and transferred to an oil bath. The oil bath temperature was raised to 150°C, and the mixture was stirred for 10 hours to allow it to react completely. After the reaction, the precipitate was filtered, washed with water, and dried to obtain green copper-zinc ore.

[0049] (3) Mixing

[0050] Weigh 25.00g of the spinel phase copper aluminate and 12.50g of green copper zinc ore obtained above, mix and grind them evenly to obtain the copper compound.

[0051] 2. Catalyst Preparation

[0052] (1) Preparation of solid powder

[0053] Weigh out 35.00g of the above copper compound, 7.50g of manganese carbonate, 1.00g of yttrium oxide, 1.50g of praseodymium oxide, 1.20g of magnesium hydroxide, and 3.80g of calcium hydroxide, and mix them evenly to obtain a solid mixture. Transfer the obtained solid mixture to a polytetrafluoroethylene ball milling jar containing zirconia grinding balls. At a mass ratio of zirconia grinding balls to solid mixture of 4:1, ball mill at a speed of 200r / min for 1h, and sieve to obtain a solid powder of 200-300 mesh.

[0054] (2) Preparation of molding aids

[0055] Weigh out 4.00g of ammonium bicarbonate, 0.16g of silica sol and 10.00g of water, mix and stir evenly to obtain the molding aid.

[0056] (3) Extrusion strip

[0057] Weigh 40.0g of the above solid powder, add 14.16g of the above molding aid, mix thoroughly for 30 minutes, then transfer to a mold with a diameter of 4mm for extrusion to obtain a strip catalyst with a diameter of 4mm.

[0058] (4) Drying

[0059] The obtained strip catalyst was transferred to an oven and dried at 40°C for 12 hours. Then it was placed in a muffle furnace and calcined at 350°C for 4 hours in an air atmosphere at a rate of 0.5°C / min. After cooling, it was cut to a length of 4-5 mm to obtain the corresponding catalyst.

[0060] Example 2

[0061] 1. Preparation of copper compounds

[0062] Same as Example 1.

[0063] 2. Catalyst Preparation

[0064] Weigh out 32.50g of the above copper compound, 10.00g of manganese carbonate, 1.00g of yttrium oxide, 1.50g of praseodymium oxide, 1.20g of magnesium hydroxide, and 3.80g of calcium hydroxide, mix them evenly to obtain a solid mixture, and the remaining preparation steps are the same as in Example 1.

[0065] Example 3

[0066] 1. Preparation of copper compounds

[0067] Same as Example 1.

[0068] 2. Catalyst Preparation

[0069] Weigh out 37.50g of the above copper compound, 5.00g of manganese carbonate, 1.00g of yttrium oxide, 1.50g of praseodymium oxide, 1.20g of magnesium hydroxide, and 3.80g of calcium hydroxide, mix them evenly to obtain a solid mixture, and the remaining preparation steps are the same as in Example 1.

[0070] Example 4

[0071] 1. Preparation of copper compounds

[0072] Same as Example 1.

[0073] 2. Catalyst Preparation

[0074] Weigh 35.00g of the above copper compound, 7.50g of manganese carbonate, 1.50g of yttrium oxide, 1.00g of praseodymium oxide, 1.20g of magnesium hydroxide, and 3.80g of calcium hydroxide, and mix them evenly to obtain a solid mixture. The remaining preparation steps are the same as in Example 1.

[0075] Example 5

[0076] 1. Preparation of copper compounds

[0077] Same as Example 1.

[0078] 2. Catalyst Preparation

[0079] Weigh out 37.50g of the above copper compound, 7.50g of manganese carbonate, 1.20g of magnesium hydroxide, and 3.80g of calcium hydroxide, mix them evenly to obtain a solid mixture, and the remaining preparation steps are the same as in Example 1.

[0080] Example 6

[0081] 1. Preparation of copper compounds

[0082] Same as Example 1.

[0083] 2. Catalyst Preparation

[0084] Weigh out 32.50g of the above copper compound, 7.50g of manganese carbonate, 1.00g of yttrium oxide, 1.50g of praseodymium oxide, 1.79g of magnesium hydroxide, and 5.70g of calcium hydroxide, and mix them evenly to obtain a solid mixture. The remaining preparation steps are the same as in Example 1.

[0085] Example 7

[0086] 1. Preparation of copper compounds

[0087] Same as Example 1.

[0088] 2. Catalyst Preparation

[0089] Weigh 37.50g of the above copper compound, 10.0g of manganese carbonate, 1.00g of yttrium oxide, and 1.50g of praseodymium oxide, mix them evenly to obtain a solid mixture, and the remaining preparation steps are the same as in Example 1.

[0090] Example 8

[0091] 1. Preparation of copper compounds

[0092] Same as Example 1.

[0093] 2. Catalyst Preparation

[0094] (1) Preparation of solid powder

[0095] Weigh out 32.50g of the above copper compound, 7.50g of manganese carbonate, 1.00g of yttrium oxide, 1.50g of praseodymium oxide, 1.79g of magnesium hydroxide, and 5.70g of calcium hydroxide, and mix them evenly to obtain a solid mixture. Transfer the obtained solid mixture to a polytetrafluoroethylene ball milling jar containing zirconia grinding beads. At a mass ratio of zirconia grinding beads to solid mixture of 4:1, ball mill at a speed of 200r / min for 1h, and sieve to obtain a solid powder of 200-300 mesh.

[0096] (2) Preparation of molding aids

[0097] Weigh out 4.50g of ammonium bicarbonate, 1.80g of silica sol and 11.25g of water, mix and stir evenly to obtain the molding aid.

[0098] (3) Extrusion strip

[0099] Weigh 40.0g of the above solid powder, add 17.55g of the above molding aid, mix thoroughly for 30 minutes, then transfer to a mold with a diameter of 4mm for extrusion to obtain a strip catalyst with a diameter of 4mm.

[0100] (4) Drying

[0101] The obtained strip catalyst was transferred to an oven and dried at 40°C for 12 hours. Then it was placed in a muffle furnace and calcined at 350°C for 4 hours in an air atmosphere. After cooling, it was cut to a length of 4-5 mm to obtain the corresponding catalyst.

[0102] Example 9

[0103] 1. Preparation of copper compounds

[0104] Same as Example 1.

[0105] 2. Catalyst Preparation

[0106] (1) Preparation of solid powder

[0107] Weigh out 32.50g of the above copper compound, 7.50g of manganese carbonate, 1.00g of yttrium oxide, 1.50g of praseodymium oxide, 1.79g of magnesium hydroxide, and 5.70g of calcium hydroxide, and mix them evenly to obtain a solid mixture. Transfer the obtained solid mixture to a polytetrafluoroethylene ball milling jar containing zirconia grinding beads. At a mass ratio of zirconia grinding beads to solid mixture of 4:1, ball mill at a speed of 200r / min for 1h, and sieve to obtain a solid powder of 200-300 mesh.

[0108] (2) Preparation of molding aids

[0109] Weigh out 4.50g of ammonium bicarbonate, 1.80g of silica sol and 11.25g of water, mix and stir evenly to obtain the molding aid.

[0110] (3) Extrusion strip

[0111] Weigh 40.0g of the above solid mixture, add 17.55g of the above molding aid, knead thoroughly for 30 minutes, then transfer to a mold with a diameter of 4mm for extrusion to obtain a strip-shaped catalyst with a diameter of 4mm.

[0112] (4) Drying

[0113] The obtained strip catalyst was transferred to an oven and dried at 40°C for 12 hours. Then it was placed in a muffle furnace and calcined at 420°C for 4 hours in an air atmosphere. After cooling, it was cut to a length of 4-5 mm to obtain the corresponding catalyst.

[0114] Example 10

[0115] 1. Preparation of copper compounds

[0116] Same as Example 1.

[0117] 2. Catalyst Preparation

[0118] (1) Preparation of solid powder

[0119] Weigh out 32.50g of the above copper compound, 7.50g of manganese carbonate, 1.00g of yttrium oxide, 1.50g of praseodymium oxide, 1.79g of magnesium hydroxide, and 5.70g of calcium hydroxide, and mix them evenly to obtain a solid mixture. Transfer the obtained solid mixture to a polytetrafluoroethylene ball milling jar containing zirconia grinding beads. At a mass ratio of zirconia grinding beads to solid mixture of 4:1, ball mill at a speed of 200r / min for 1h, and sieve to obtain a solid powder of 200-300 mesh.

[0120] (2) Preparation of molding aids

[0121] Weigh out 4.50g of ammonium bicarbonate, 1.80g of silica sol and 11.25g of water, mix and stir evenly to obtain the molding aid.

[0122] (3) Extrusion strip

[0123] Weigh 40.0g of the above solid mixture, add 17.55g of the above molding aid, knead thoroughly for 30 minutes, then transfer to a mold with a diameter of 2mm for extrusion to obtain a strip-shaped catalyst with a diameter of 2mm.

[0124] (4) Drying

[0125] The obtained strip catalyst was transferred to an oven and dried at 40°C for 12 hours. Then it was placed in a muffle furnace and calcined at 420°C for 4 hours in an air atmosphere. After cooling, it was cut to a length of 4-5 mm to obtain the corresponding catalyst.

[0126] The inventors tested and analyzed the average radial strength and performance of the catalysts prepared in Examples 1-10 above in the high-temperature methanol reforming catalytic hydrogen reaction. The specific methods are as follows:

[0127] The average radial strength of the catalyst (i.e., the mechanical strength of the catalyst) was measured using a particle strength tester, in N / cm.

[0128] Performance testing of catalytic hydrogenation in high-temperature methanol reforming: The test was conducted in a fixed-bed microreactor. A catalyst sample of 2.0 g was used, with quartz sand as an inert bed to immobilize the catalyst in the temperature-controlled section of the reactor tubes. The reaction temperature was 400℃, the reaction pressure was 1.6 MPa, and the reactants were a solution of methanol and water at a mass ratio of 1:1. The feed hourly space velocity (WHSV) was 0.9 h⁻¹. -1 .

[0129] The CO concentration of the outflow gas was analyzed online using a Fuli gas-liquid chromatograph. The condensate was collected per unit reaction time, and the CH3OH concentration was analyzed to calculate the residual amount. The chromatograph was equipped with dual detectors, TCD and FID, and the packed column was TDX-01.

[0130] The methanol conversion rate is calculated based on the number of carbon moles, specifically as follows:

[0131] Methanol conversion rate: (total CH3OH - residual CH3OH) / total CH3OH, where total CH3OH represents the total molar amount of methanol entering the reaction apparatus, and residual CH3OH represents the molar amount of methanol remaining in the tail liquid after the reaction.

[0132] CO concentration in the catalytic product gas: Calculated by peak fitting of the full spectrum of the product gas gas using the area normalization method.

[0133] The test results are shown in Table 1 below.

[0134] Table 1. Performance evaluation test results of the catalysts prepared in Examples 1-10

[0135]

[0136] Comparative analysis of the data in Table 1:

[0137] The data comparison of Examples 1-3 shows that the mechanical strength and thermal stability of the catalyst in Example 2 are better than those of the catalysts in Example 1 and Example 3, indicating that within the mass percentage range of the present invention, increasing the proportion of manganese carbonate can improve the mechanical strength and thermal stability of the catalyst.

[0138] A comparison of the data from Examples 1 and 4 shows that the activity and stability of the catalysts are comparable, indicating that changing the ratio of yttrium oxide and praseodymium oxide has almost no effect on the performance of the catalyst. However, a comparison of the data from Examples 4 and 5 shows that the activity and stability of the catalyst in Example 5 are significantly lower than those in Example 4, while the CO concentration in the catalytic product gas is higher. This indicates that the catalyst prepared without the addition of the rare earth elements of this invention has poor catalytic activity and stability, and produces more byproducts.

[0139] A comparison of the data from Examples 1 and 6 shows that the catalyst in Example 6 exhibits improved stability and mechanical strength, and a lower CO concentration in the catalytic product gas. This indicates that within the mass percentage range of the present invention, increasing the proportion of alkali metal compounds can improve the stability and mechanical strength of the catalyst and reduce byproducts. However, a comparison of the data from Examples 6 and 7 shows that, compared to the catalyst in Example 6, the catalyst in Example 7 exhibits significantly reduced mechanical strength and stability, while the CO concentration in the product gas increases. This indicates that the catalyst prepared without the addition of the alkali metal compounds of the present invention has reduced mechanical strength and stability, and produces more byproducts.

[0140] A comparison of the data from Examples 8 and 9 shows that the mechanical strength of the catalyst in Example 9 is improved compared to Example 8, indicating that within the calcination temperature range of the present invention, increasing the calcination temperature can improve the mechanical strength of the catalyst. A comparison of the data from Examples 9 and 10 shows that, compared to Example 10, the mechanical strength, stability, and CO concentration in the catalytic product gas of the two small-sized strip catalysts are not significantly different, indicating that preparing a catalyst with a diameter smaller than that of the present invention (3-8 mm) has basically no effect on improving the performance of the catalyst.

[0141] The inventors also performed XRD scans on the catalysts of Examples 1-10 above, and the obtained scan patterns are as follows: Figure 1 As shown. By Figure 1 It can be seen that there are no obvious CuO and CuAl2O4 diffraction characteristic peaks in the catalysts of Examples 1-10, indicating that the Cu-containing phases in the catalysts of Examples 1-10 are all highly dispersed.

[0142] The inventors also performed electron microscopy scanning on the elements in the catalyst of Example 9, and the resulting scanning electron microscope images are shown below. Figure 2 As shown. By Figure 2 It can be seen that Cu is highly dispersed in the catalyst.

[0143] The above description is a detailed description of the preferred embodiments of the present invention. However, the embodiments are not intended to limit the scope of the patent application of the present invention. All equivalent changes or modifications made under the technical spirit of the present invention should fall within the patent scope covered by the present invention.

Claims

1. A method for preparing a high-temperature methanol-water reforming hydrogen production copper-manganese rare earth catalyst, characterized in that, Includes the following steps: (1) A solid mixture is prepared by mixing four components, namely copper compound, manganese carbonate, rare earth oxide and alkali metal compound, in a mass percentage ratio of 60-70%:15-20%:1-5%:5-15%, and the sum of the mass percentages of the four components is 100%. The solid mixture is added to a polytetrafluoroethylene ball milling jar containing zirconia grinding beads, and the ball milling jar is placed in a ball mill and ball milled at a speed of 150-250 r / min for 1-2 h to obtain a solid powder with a particle size of 200-300 mesh. The copper compound is a mixture of copper aluminate and zirconia ore. The rare earth oxide is yttrium oxide and / or praseodymium oxide. The alkali metal compound is a mixture of magnesium hydroxide and calcium hydroxide. (2) Add molding aid to the above solid powder, knead for 30 minutes, and then put it into an extruder for extrusion to obtain a strip catalyst with a diameter of 2-5 mm; the molding aid includes ammonium bicarbonate, silica sol and water; (3) The obtained strip catalyst was placed in an oven and dried at 40°C for 12 h; (4) The dried strip catalyst is transferred to a muffle furnace and calcined in an air atmosphere at 350-450℃ for 4-6 h. After cooling, it is cut into small segments of 3-8 mm to obtain the methanol-water reforming hydrogen copper-manganese rare earth catalyst.

2. The preparation method of the high-temperature methanol-water reforming copper-manganese rare earth catalyst for hydrogen production according to claim 1, characterized in that, In step (1), the mass ratio of copper aluminate to copper zinc ore is 2:

1.

3. The preparation method of the copper-manganese rare earth catalyst for high-temperature methanol-water reforming to hydrogen production according to claim 1, characterized in that, In step (1), the copper aluminate is spinel phase copper aluminate.

4. The preparation method of the copper-manganese rare earth catalyst for high-temperature methanol-water reforming to hydrogen production according to claim 3, characterized in that, The preparation method of the spinel phase copper aluminate is as follows: according to the Cu / Al molar ratio of 1:2, pseudoboehmite is repeatedly impregnated in copper nitrate solution. After impregnation, the pseudoboehmite is dried, uniformly ball-milled for 1 hour, and then placed in a muffle furnace. The temperature is raised to 950°C at a rate of 2°C / min and then cooled to obtain the spinel phase copper aluminate.

5. The method for preparing a high-temperature methanol-water reforming copper-manganese rare earth catalyst for hydrogen production according to claim 1, characterized in that, In step (1), the preparation method of the green copper zinc ore is as follows: according to the molar ratio of Cu / Zn of 2:3, a suspension of copper hydroxide, zinc hydroxide and sodium carbonate is placed in a crystallization reaction vessel and subjected to a hydrothermal synthesis reaction at 150°C. Then, the mixture is filtered, washed with water and dried to obtain the green copper zinc ore.

6. The method for preparing a high-temperature methanol-water reforming copper-manganese rare earth catalyst for hydrogen production according to claim 1 or 5, characterized in that, The green copper-zinc ore is (Cu 0.4 Zn 0.6 )2(OH)2CO3、(Cu 0.3 Zn 0.7 )2(OH)2CO3、(Cu 0.2 Zn 0.8 )2(OH)2CO3 and (Cu 0.1 Zn 0.9 At least one of )2(OH)2CO3.

7. The method for preparing a high-temperature methanol-water reforming copper-manganese rare earth catalyst for hydrogen production according to claim 1, characterized in that, In step (1), the molar ratio of Mg / Ca in the mixture of magnesium hydroxide and calcium hydroxide is 0.2-0.5:

1.

8. The method for preparing a high-temperature methanol-water reforming copper-manganese rare earth catalyst for hydrogen production according to claim 1, characterized in that, In step (1), the mass ratio of the solid mixture to the zirconia grinding beads is 1:

4.

9. The preparation method of a high-temperature methanol-water reforming copper-manganese rare earth catalyst for hydrogen production according to claim 1, characterized in that, In step (2), the mass ratio of the molding aid to the solid powder is 0.3-0.5.

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