Ammonia gas cracking device of plasma coupled catalyst and preparation method of catalyst and catalyst carrier of ammonia gas cracking device
By designing the arc discharge zone and the spatial matching of the catalyst module in the ammonia cracking device, a catalyst carrier carrying the active components is prepared, which solves the problems of high energy consumption and catalyst deactivation in the hydrogen production process of ammonia gas decomposition and achieves high efficiency ammonia conversion.
Patent Information
- Application Number
- CN202510607795.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-13
- Publication Date
- 2025-08-01
AI Technical Summary
In the prior art, the hydrogen production process of ammonia gas decomposition has problems such as high energy consumption, easy sintering and inactivation of catalysts, low utilization of active particles and insufficient energy transfer efficiency. In particular, traditional thermal catalysis methods and emerging plasma catalysis technologies have insufficient ammonia conversion and energy utilization.
By designing an ammonia cracking device for plasma coupled catalysts, the arc discharge zone is used to spatially match the catalyst module to realize the utilization of energy gradients, and combining high-temperature thermal effects and high-energy electronic activation, a catalyst carrier carrying active components is prepared, including processing cylindrical support, calcining, acid/alkali etching, coating transition layer and loading precious metal precursors, to make a honeycomb catalyst carrier.
It significantly improves the ammonia conversion rate, solves the problems of high energy consumption and catalyst deactivation, and realizes an efficient ammonia decomposition and hydrogen production process.
Smart Images
Figure CN120393900A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to an ammonia cracking device with a plasma-coupled catalyst, and a preparation method for the catalyst and the catalyst carrier thereof. Background Art
[0002] Ammonia is regarded as an ideal hydrogen energy carrier due to its high hydrogen storage density (17.6 wt%) and easy liquefaction characteristics. However, the process of decomposing ammonia to produce hydrogen faces double challenges of energy efficiency and reaction rate. The traditional thermal catalytic method needs to operate at a high temperature of >600°C, with high energy consumption and easy sintering and deactivation of the catalyst. The emerging plasma catalytic technology can reduce the reaction temperature, but is limited by low utilization rate of active particles and insufficient energy transfer efficiency. For example, dielectric barrier discharge (DBD) plasma, due to its low-temperature characteristics (gas temperature close to room temperature) and the random distribution of micro-discharge filaments, is difficult to stimulate the deep dissociation of ammonia, resulting in generally low ammonia conversion rate (<10%), and the thermal effect cannot be used to synergistically enhance the catalytic activity.
[0003] In contrast, alternating current arc discharge plasma has characteristics of high energy density, local ultra-high temperature and continuous discharge, and can directly break the N-H bond through double paths of thermal cracking and high-energy electron bombardment, significantly improving the reaction kinetics. However, there are problems such as uncontrollable generation of by-products (such as nitrides) and serious energy dissipation in single arc discharge. In addition, traditional powder catalysts are prone to sintering or local overheating and deactivation at the arc high temperature, and the gas-solid contact efficiency is low. Summary of the Invention
[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide an ammonia cracking device with a plasma-coupled catalyst, and a preparation method for the catalyst and the catalyst carrier thereof, realizing the spatial matching of the arc discharge area and the catalyst module, achieving the utilization of energy gradient, the high-temperature thermal effect, the activation of high-energy electrons and the deep coupling of the surface reaction of the catalyst.
[0005] To achieve the above purpose, the first technical solution of the present invention is realized as follows. It is an ammonia cracking device with a plasma-coupled catalyst, characterized by comprising: An intake cavity, a quartz tube and an outlet cavity; the intake cavity is installed at the intake end of the quartz tube, and the intake port of the intake cavity is communicated with the intake end of the quartz tube. The outlet cavity is installed at the outlet end of the quartz tube, and the outlet port of the outlet cavity is communicated with the outlet end of the quartz tube; and A catalyst carrier loaded with active components, a high-voltage electrode rod and a grounding electrode rod; the catalyst carrier is located in the middle of the quartz tube, and the gas at the intake end of the quartz tube passes through the catalyst carrier and then is discharged from the outlet end of the quartz tube. The electrode ends of the high-voltage electrode rod and the grounding electrode rod are located in the catalyst carrier to generate an arc in the catalyst carrier, and the distance between the electrode ends of the high-voltage electrode rod and the grounding electrode rod is 2-10 mm.
[0006] In this technical solution, a cylindrical perforation is provided in the catalyst carrier, and the electrode ends of the high-voltage electrode rod and the ground electrode rod are located in the cylindrical perforation of the catalyst carrier. The inner diameter of the cylindrical perforation of the catalyst carrier is greater than the distance between the electrode ends of the high-voltage electrode rod and the ground electrode rod.
[0007] In order to achieve the above object, the second technical solution of the present invention is implemented as follows. It is an ammonia cracking device of a plasma-coupled catalyst and a preparation method of its catalyst and catalyst carrier, which is characterized by including the following steps: Step 1 Process at least one of cordierite honeycomb ceramics, foam ceramics, FeCrAl alloy, porous alumina, and silicon carbide into a cylinder, cut off a piece of the cylinder axially to form a perforation, and the radius of the perforation is greater than the electrode spacing. Step 2 The cylinder processed in Step 1 is calcined at 600 - 800 °C for 1 - 3 hours. Acid / alkali etching or transition layer coating can be optionally added. The acid includes nitric acid or hydrochloric acid. The concentration of nitric acid is 5 - 15 wt%, and the concentration of hydrochloric acid is 3 - 10 wt%. The alkali includes sodium hydroxide solution, and the concentration of sodium hydroxide is 1 - 5 mol / L. The transition layer includes Al2O3 or SiO2 sol coating, and the coating thickness of the transition layer is 10 - 50 μm. Step 3 Perform equal-volume impregnation, ultrasonic-assisted impregnation, or vacuum impregnation on the carrier processed in Step 2, repeat 2 - 5 times, with a loading amount of 0.5 - 5 wt%. The impregnating solution components include noble metal precursors or transition metal precursors and solvents. The precursors include chlorides or nitrates of Ru, Pt, Pd, Rh, Ni, Co, or Fe. The solvents include acidic aqueous solutions or mixtures of ethanol and water. The mass concentration ratio of the precursor to the solvent is 5 - 20 g / L. After the loading is completed, remove the excess impregnating solution by centrifugation.
[0008] Step 4 Place the carrier after Step 3 in air or an inert atmosphere and treat it at 400 - 600 °C for 2 - 4 hours, with a heating rate of 1 - 10 °C / min to convert the precursor into an oxide. Step 5 Place the calcined carrier into a mixed gas of H2 and N2, or a mixed gas of H2 and Ar, or a CO atmosphere. The proportion of H2 is 1 - 10%, and reduce it at 300 - 600 °C for 2 - 6 hours to make a honeycomb catalyst carrier with a catalyst.
[0009] In this technical solution, in Step 2, the carrier is first placed in acid or alkali etching or transition layer coating and then calcined at 600 - 800 °C for 1 - 3 hours.
[0010] In this technical solution, polyvinylpyrrolidone is added as a nano-dispersant to the impregnation solution in Step 3, and the mass ratio of polyvinylpyrrolidone to the metal precursor is 1:10 to 1:5 to inhibit the aggregation of metal particles.
[0011] In this technical solution, the acid includes nitric acid or hydrochloric acid, the concentration of nitric acid is 5-15 wt%, and the concentration of hydrochloric acid is 3-10 wt%; the base includes sodium hydroxide solution, and the concentration of sodium hydroxide is 1-5 mol / L; the transition layer includes an Al2O3 or SiO2 sol coating, and the coating thickness of the transition layer is 10-50 μm.
[0012] In this technical solution, a second component and an auxiliary agent are introduced by impregnation in Step 3. The second component is a composite active component of Ru and Ni, and the molar ratio of Ru to Ni is 1:10 to 1:1; the auxiliary agent includes CeO2 or La2O3 or K2O, and based on the total mass of the catalyst, the proportion of the auxiliary agent is 0.1-3 wt%, which is used to improve the anti-coking ability.
[0013] The advantages of the present invention compared with the prior art are as follows: the spatial matching between the arc discharge area and the catalyst module realizes the utilization of energy gradient, high-temperature thermal effect, and the deep coupling of high-energy electron activation and the surface reaction of the catalyst. Brief Description of the Drawings
[0014] Figure 1 is a schematic structural diagram of the present invention; Figure 2 is a top view of the present invention; Figure 3 is Figure 2 the A-A cross-sectional view of Figure 4 is the voltage curve at different ammonia gas flow rates when the input power of the present invention is 90 W; Figure 5 is the voltage curve at different input powers when the ammonia gas inlet flow rate of the present invention is 100 ml / min; Figure 6 is the ammonia conversion rate under different ammonia gas flow rates and different input power conditions with an electrode gap of 8 mm. Detailed Embodiments
[0015] The following further describes the detailed embodiments of the present invention with reference to the drawings. It should be noted here that the description of these embodiments is for helping to understand the present invention, but does not limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. Embodiment
[0016] As shown Figures 1 to 3 in the figure, it is an ammonia cracking device with a plasma-coupled catalyst, including: An intake chamber 2, a quartz tube 3, and an outlet chamber 4; the intake chamber 2 is installed at the intake end of the quartz tube 3, and the intake port 21 of the intake chamber 2 is communicated with the intake end of the quartz tube 3. The outlet chamber 4 is installed at the outlet end of the quartz tube 3, and the outlet port 41 of the outlet chamber 4 is communicated with the outlet end of the quartz tube 3; and A catalyst support 6 loaded with an active component, a high-voltage electrode rod 1, and a grounding electrode rod 5; the catalyst support 6 is located in the middle of the quartz tube 3. The gas at the intake end of the quartz tube 3 passes through the catalyst support 6 and then is discharged from the outlet end of the quartz tube 3. The electrode ends of the high-voltage electrode rod 1 and the grounding electrode rod 5 are located in the catalyst support 6 to generate an arc in the catalyst support 6. The distance between the electrode ends of the high-voltage electrode rod 1 and the grounding electrode rod 5 is 2 - 10 mm.
[0017] During operation, connect the electrodes, place a catalyst in the coupling area of the electrode spacing, introduce ammonia into the quartz tube reactor, start the high-voltage power supply to generate arc plasma, and use the arc thermal effect and the synergistic effect of the catalyst to achieve ammonia decomposition:
[0018] In this embodiment, a cylindrical perforation is provided in the catalyst support 6. The electrode ends of the high-voltage electrode rod 1 and the grounding electrode rod 5 are located in the cylindrical perforation of the catalyst support 6. The inner diameter of the cylindrical perforation of the catalyst support 6 is greater than the distance between the electrode ends of the high-voltage electrode rod 1 and the grounding electrode rod 5. Embodiment
[0019] As shown Figures 1 to 3 in the figure, it is an ammonia cracking device with a plasma-coupled catalyst, and a preparation method of the ammonia cracking device with a plasma-coupled catalyst, its catalyst, and its catalyst support, which is characterized by including the following steps: Step 1 Process at least one of cordierite honeycomb ceramics, foam ceramics, FeCrAl alloy, porous alumina, and silicon carbide into a cylinder, cut off a piece of the cylinder along the axial direction to form a perforation 32, and the radius of the perforation 32 is greater than the electrode spacing; Step 2 The cylinder processed in Step 1 is calcined at 600 - 800 °C for 1 - 3 hours. Acid / alkali etching or transition layer coating can be optionally added. The acid includes nitric acid or hydrochloric acid. The concentration of nitric acid is 5 - 15 wt%, and the concentration of hydrochloric acid is 3 - 10 wt%. The alkali includes sodium hydroxide solution, and the concentration of sodium hydroxide is 1 - 5 mol / L. The transition layer includes an Al2O3 or SiO2 sol coating, and the coating thickness of the transition layer is 10 - 50 μm; Step 3 The carrier processed in Step 2 is subjected to equal-volume impregnation, ultrasonic-assisted impregnation, or vacuum impregnation, with the number of repetitions being 2 - 5 times, the loading amount being 0.5 - 5 wt%, and the impregnating solution components including a noble metal precursor or a transition metal precursor and a solvent. The precursor includes chlorides or nitrates of Ru, Pt, Pd, Rh, Ni, Co, or Fe, and the solvent includes an acidic aqueous solution or a mixed solution of ethanol and water. The mass concentration ratio of the precursor to the solvent is 5 - 20 g / L. After the loading is completed, the excess impregnating solution is removed by centrifugation.
[0020] Step 4 The carrier after Step 3 is treated at 400 - 600 °C for 2 - 4 hours in air or an inert atmosphere, with a heating rate of 1 - 10 °C / min, to convert the precursor into an oxide. Step 5 The calcined carrier is placed in a mixed gas of H2 and N2, a mixed gas of H2 and Ar, or a CO atmosphere. The proportion of H2 is 1 - 10%, and it is reduced at 300 - 600 °C for 2 - 6 hours to produce a honeycomb catalyst carrier 2 with a catalyst. Optionally, a nano-dispersant such as PVP is added to inhibit metal agglomeration.
[0021] In this embodiment, in Step 2, the carrier is first placed in an acid or base for etching or a transition layer is coated, and then it is calcined at 600 - 800 °C for 1 - 3 hours.
[0022] In this embodiment, polyvinylpyrrolidone is added as a nano-dispersant to the impregnating solution in Step 3, and the mass ratio of polyvinylpyrrolidone to the metal precursor is 1:10 to 1:5 to inhibit metal particle agglomeration.
[0023] In this embodiment, the acid includes nitric acid or hydrochloric acid. The concentration of nitric acid is 5 - 15 wt%, and the concentration of hydrochloric acid is 3 - 10 wt%. The base includes a sodium hydroxide solution, and the concentration of sodium hydroxide is 1 - 5 mol / L. The transition layer includes an Al2O3 or SiO2 sol coating, and the coating thickness of the transition layer is 10 - 50 μm.
[0024] In this embodiment, a second component and an additive are introduced during the impregnation in Step 3. The second component is a composite active component of Ru and Ni, and the molar ratio of Ru to Ni is 1:10 to 1:1. The additive includes CeO2, La2O3, or K2O, and based on the total mass of the catalyst, the proportion of the additive is 0.1 - 3 wt% to improve the anti-coking ability.
[0025] The above has made a detailed description of the embodiments of the present invention in conjunction with the accompanying drawings, but the present invention is not limited to the described embodiments. For those of ordinary skill in the art, various changes, modifications, substitutions, and variations of these embodiments still fall within the protection scope of the present invention without departing from the principles and purposes of the present invention.
Claims
1. An ammonia cracking device with a plasma-coupled catalyst, characterized in that Comprising: An intake chamber (2), a quartz tube (3) and an exhaust chamber (4); the intake chamber (2) is installed at the intake end of the quartz tube (3), and the intake port (21) of the intake chamber (2) is communicated with the intake end of the quartz tube (3), the exhaust chamber (4) is installed at the exhaust end of the quartz tube (3), and the exhaust port (41) of the exhaust chamber (4) is communicated with the exhaust end of the quartz tube (3); and A catalyst carrier (6) loaded with an active component, a high-voltage electrode rod (1) and a grounding electrode rod (5); the catalyst carrier (6) is located in the middle of the quartz tube (3), and the gas at the intake end of the quartz tube (3) is discharged from the exhaust end of the quartz tube (3) after passing through the catalyst carrier (6), the electrode ends of the high-voltage electrode rod (1) and the grounding electrode rod (5) are located in the catalyst carrier (6) so as to generate an electric arc in the catalyst carrier (6), and the distance between the electrode ends of the high-voltage electrode rod (1) and the grounding electrode rod (5) is 2-10 mm.
2. The ammonia cracking device of the plasma-coupled catalyst according to claim 1, characterized in that A cylindrical perforation is provided in the catalyst carrier (6), the electrode ends of the high-voltage electrode rod (1) and the grounding electrode rod (5) are located in the cylindrical perforation of the catalyst carrier (6), and the inner diameter of the cylindrical perforation of the catalyst carrier (6) is greater than the distance between the electrode ends of the high-voltage electrode rod (1) and the grounding electrode rod (5).
3. The ammonia cracking device of the plasma-coupled catalyst, its catalyst and the preparation method of the catalyst carrier according to claim 1, characterized in that Including the following steps: Step One At least one of cordierite honeycomb ceramics, foam ceramics, ferritic chromium-aluminum alloy, porous alumina and silicon carbide is processed into a cylinder, and a piece of the cylinder is cut axially to form a perforation (32), and the radius of the perforation (32) is greater than the electrode distance; Step Two The cylinder processed in Step One is calcined at 600-800 °C for 1-3 hours, and acid / alkali etching or transition layer coating can be optionally added. The acid includes nitric acid or hydrochloric acid, the concentration of nitric acid is 5-15 wt%, and the concentration of hydrochloric acid is 3-10 wt%; the alkali includes sodium hydroxide solution, and the concentration of sodium hydroxide is 1-5 mol / L; the transition layer includes an Al2O3 or SiO2 sol coating, and the coating thickness of the transition layer is 10-50 μm; Step Three The carrier treated in Step Two is subjected to equal-volume impregnation or ultrasonic-assisted impregnation or vacuum impregnation, and the number of repetitions is 2-5 times, the loading amount is 0.5-5 wt%, and the impregnation liquid components include a noble metal precursor or a transition metal precursor and a solvent. The precursor includes chlorides or nitrates of Ru or Pt or Pd or Rh or Ni or Co or Fe, and the solvent includes an acidic aqueous solution or a mixed solution of ethanol and water. The mass concentration ratio of the precursor to the solvent is 5-20 g / L. After the loading is completed, the excess impregnation liquid is removed by centrifugation; Step Four The carrier after Step Three is treated at 400-600 °C in air or an inert atmosphere for 2-4 hours, and the heating rate is 1-10 °C / min to convert the precursor into an oxide; Step Five Put the calcined support into a mixed gas of H2 and N2 or a mixed gas of H2 and Ar or a CO atmosphere. The proportion of H2 is 1-10%, and reduce it at 300-600°C for 2-6 hours to make a honeycomb catalyst support (2) with a catalyst. Optionally, add a nano-dispersant (such as PVP) to inhibit metal agglomeration.
4. The ammonia cracking device of the plasma-coupled catalyst and the preparation method of the catalyst and the catalyst carrier according to claim 5, characterized in that In the second step, first put the support into acid or alkali etching or transition layer coating, and then calcine it at 600-800°C for 1-3 hours.
5. The ammonia cracking device of the plasma-coupled catalyst and the preparation method of the catalyst and the catalyst carrier according to claim 5, characterized in that Add polyvinylpyrrolidone as a nano-dispersant to the impregnation solution in the third step. The mass ratio of polyvinylpyrrolidone to the metal precursor is 1:10 to 1:5 to inhibit metal particle agglomeration.
6. The ammonia cracking device of the plasma-coupled catalyst and the preparation method of the catalyst and the catalyst carrier according to claim 6, characterized in that The acid includes nitric acid or hydrochloric acid. The concentration of nitric acid is 5-15 wt%, and the concentration of hydrochloric acid is 3-10 wt%. The alkali includes sodium hydroxide solution, and the concentration of sodium hydroxide is 1-5 mol / L. The transition layer includes an Al2O3 or SiO2 sol coating, and the coating thickness of the transition layer is 10-50μm.
7. The ammonia cracking device of the plasma-coupled catalyst and the preparation method of the catalyst and the catalyst carrier according to claim 5, characterized in that Introduce the second component and the promoter by impregnation in the third step. The second component is a composite active component of Ru and Ni, and the molar ratio of Ru to Ni is 1:10 to 1:
1. The promoter includes CeO2 or La2O3 or K2O. Based on the total mass of the catalyst, the proportion of the promoter is 0.1-3 wt% to improve the anti-coking ability.