Bifunctional catalyst for ammonia synthesis and decomposition and reaction separation system

Abstract

The invention discloses a bifunctional catalyst for ammonia synthesis and decomposition and a reaction separation system, the bifunctional catalyst is a ruthenium-based catalyst, the active component of the bifunctional catalyst is Ru nano-particles, the Ru nano-particles are loaded on a perovskite type carrier La1-xSrxAlO3 (x is greater than or equal to 0.2 and less than or equal to 0.3), the loading amount of Ru is 2-4wt%, and the particle size is 3-6nm. The system integrates a bifunctional reactor, an ammonia permeable membrane assembly, a recycle gas compressor, a nitrogen-hydrogen compressor, a condenser, an ammonia storage tank, a hydrogen-nitrogen separation membrane assembly and a valve group, and flexible conversion between ammonia synthesis and decomposition modes is realized through valve switching. In an ammonia synthesis mode, efficient circulation of unreacted hydrogen and nitrogen can be achieved, and the total conversion rate is larger than or equal to 90%; in an ammonia decomposition mode, ammonia can be efficiently decomposed, high-purity hydrogen can be obtained through separation, and the decomposition rate reaches 90%. The system has the advantages of high catalyst universality, high integration level, low equipment investment, low energy consumption and the like, and is suitable for the field of green ammonia energy storage and hydrogen energy conversion.

Description

Technical Field

[0001] This invention belongs to the field of chemical catalysis and reaction engineering, specifically relating to a bifunctional catalyst for ammonia synthesis and ammonia decomposition reactions and its matching reaction separation system. Background Technology

[0002] Green ammonia (ammonia synthesized from hydrogen produced from renewable energy sources and nitrogen) has become a highly promising cross-seasonal energy storage carrier and indirect hydrogen energy carrier due to its advantages such as high energy density, easy storage and transportation, and zero carbon emissions. The application of green ammonia requires achieving a "two-step core process": first, timely conversion of intermittent hydrogen produced from renewable energy sources (such as wind power and photovoltaics) into ammonia for long-term storage; and second, efficient decomposition of ammonia into hydrogen for energy supply when needed. Therefore, developing a process system with both "ammonia synthesis and ammonia decomposition" functions is key to promoting the large-scale application of green ammonia.

[0003] However, existing technologies face significant bottlenecks in the synthesis and decomposition of green ammonia, specifically: 1) Incompatibility of catalysts: The mainstream ammonia synthesis reaction uses iron-based (high temperature and high pressure) or ruthenium-based (medium temperature and medium pressure) catalysts, while the ammonia decomposition reaction relies on nickel-based, cobalt-based, or noble metal catalysts. The active sites and reaction mechanisms of these two types of catalysts are completely different, making it impossible to achieve dual functions in the same reaction. Frequent disassembly of the reactor and replacement of the catalyst are required during production, which not only increases operating time but also easily leads to catalyst loss and raw material waste. 2) Single-function reaction system: Existing equipment is mostly a "single-reaction design"—either used only for ammonia synthesis (such as traditional Haber reactors) or only for ammonia decomposition (such as fixed-bed ammonia decomposition reactors). To achieve a "storage-utilization" cycle, two independent reaction devices, separation systems, and auxiliary equipment are required, increasing equipment investment costs by more than 30%. Furthermore, the system occupies a large area, and process switching is cumbersome, making it difficult to adapt to the flexibility requirements of distributed energy storage scenarios. 3) Insufficient reaction efficiency and economy: In a single-function system, unreacted raw materials (N2 / H2 in ammonia synthesis and NH3 in ammonia decomposition) are difficult to recover efficiently, and the raw material conversion rate is generally low (the single-pass conversion rate of ammonia synthesis is usually less than 20%). At the same time, the independent operation of the two systems requires repeated consumption of energy such as compression and heating, which further reduces the overall economy of green ammonia energy storage.

[0004] In summary, existing technologies cannot meet the integrated "storage-utilization" requirements of green ammonia. There is an urgent need to develop a bifunctional catalyst that can simultaneously catalyze ammonia synthesis and decomposition, as well as an integrated reaction separation system that can be adapted to the catalyst and flexibly switch between the two reactions. This would solve problems such as high equipment investment, cumbersome operation, and poor adaptability, and improve the efficiency and economy of green ammonia energy storage. Summary of the Invention

[0005] The present invention aims to provide a bifunctional catalyst and its reaction separation system to solve the problems of non-universal catalysts, poor system flexibility, and equipment redundancy in the prior art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A bifunctional catalyst for ammonia synthesis and decomposition, wherein the bifunctional catalyst is a ruthenium-based catalyst, the active component being Ru nanoparticles supported on a perovskite support having the general chemical formula La. 1-x Sr x AlO3, wherein 0.2≤x≤0.3, Ru loading is 2-4wt%, and particle size is 3-6nm.

[0007] The preparation method of bifunctional catalysts includes the following steps: S1, perovskite support synthesis S1.1 Weigh out La(NO3)3·6H2O, Sr(NO3)2, and Al(NO3)3·9H2O in deionized water at a molar ratio of (1-x):x:1, where 0.2≤x≤0.3, to form a mixed solution with a total metal ion concentration of 0.1mol / L; S1.2 Add citric acid to the mixed solution, wherein the molar ratio of metal ions to citric acid is 1:1.5, adjust the pH of the solution to 3-4, and stir until clear; S1.3. The clarified solution is evaporated and concentrated at 80°C to a gel state, and then dried at 110-120°C for 12-16 hours to obtain a dry gel. S1.4. Place the dried gel in a muffle furnace, raise the temperature to 700-750°C at a rate of 5°C / min, and hold for 4-6 hours. After cooling, obtain La. 1-x Sr x AlO3 perovskite support; Loading and activation of S2 and Ru S2.1 Weigh RuCl3·xH2O and dissolve it in anhydrous ethanol to prepare a RuCl3 ethanol solution with a concentration of 0.02-0.05 mol / L; S2.2, Take the La obtained in step S1 1-x Sr x An AlO3 perovskite support is impregnated in a RuCl3 ethanol solution, sonicated for 1 hour, and then stirred at room temperature for 20-24 hours. After filtration, the solid product is vacuum dried at 80°C for 6-8 hours, and then placed in an H2 atmosphere. The temperature is increased to 350-450°C at a rate of 5°C / min and kept at this temperature for 2-3 hours to form a bifunctional catalyst with Ru nanoparticles of 3-6 nm in diameter supported on the surface of the perovskite support.

[0008] Preferably, the concentration of the RuCl3 ethanol solution in step S2.1 is 0.03 mol / L.

[0009] Preferably, in step S2.2, the H2 flow rate of the H2 atmosphere is 50-60 mL / min, the heating rate is increased to 450℃ and the temperature is maintained for reduction for 2-3 hours.

[0010] A bifunctional reaction separation system for ammonia synthesis and decomposition, comprising: A bifunctional reactor, which is filled with the above-mentioned bifunctional catalyst that can simultaneously catalyze the ammonia synthesis and ammonia decomposition reactions. An ammonia-permeable membrane assembly, the inlet of which is connected to the outlet of the bifunctional reactor; A circulating gas compressor, the inlet of which is connected to the first retentate side outlet of the ammonia permeation membrane module, and the outlet of which is connected to the inlet of the dual-function reactor; A nitrogen-hydrogen compressor, whose inlet is connected to the feed gas and whose outlet is connected to the dual-function reactor, is used to supply hydrogen and nitrogen feed gas to the dual-function reactor in ammonia synthesis mode. A condenser, the inlet of which is connected to the permeate-side outlet of the ammonia-permeable membrane assembly; An ammonia storage tank, the inlet of which is connected to the outlet of the condenser; A hydrogen-nitrogen separation membrane module, the inlet of which is connected to the second retardation side outlet of the ammonia permeation membrane module, is used to separate hydrogen and nitrogen in ammonia decomposition mode; And multiple valves are used to switch the system's operation between ammonia synthesis mode and ammonia decomposition mode.

[0011] Furthermore, a first valve is provided on the outlet pipe of the circulating gas compressor, a second valve is provided on the first interception side outlet pipe of the ammonia permeation membrane module, a fifth valve is provided on the second interception side outlet pipe, and the permeation side outlet pipe of the ammonia permeation membrane module is divided into two paths, one path is provided with a fourth valve connected to the condenser, and the other path is provided with a third valve connected to the inlet of the circulating gas compressor. When the system performs an ammonia synthesis reaction: the first, second, and fourth valves are opened, and the third and fifth valves are closed. The mixture of raw material hydrogen and nitrogen is compressed by the nitrogen-hydrogen compressor and enters the bifunctional reactor, where an ammonia synthesis reaction occurs under the action of a bifunctional catalyst. The reaction products enter the ammonia permeation membrane module. Unreacted nitrogen and hydrogen flow out from the first interception side of the ammonia permeation membrane module, are compressed by the circulating gas compressor, and return to the inlet of the bifunctional reactor to continue participating in the reaction. Ammonia flows out from the permeation side of the ammonia permeation membrane module, is condensed by the condenser, and stored in the ammonia storage tank. When the system performs an ammonia decomposition reaction: valves 1, 3, and 5 are opened, and valves 2 and 4 are closed. The raw material ammonia gas is compressed by the circulating gas compressor and enters the dual-function reactor, where it undergoes an ammonia decomposition reaction under the action of a dual-function catalyst. The reaction products enter the ammonia permeation membrane module, and unreacted ammonia gas flows out from the permeate side of the ammonia permeation membrane module, is compressed by the circulating gas compressor, and returns to the inlet of the dual-function reactor to continue participating in the reaction. The nitrogen and hydrogen mixture produced by the decomposition flows out from the second interception side of the ammonia permeation membrane module and enters the hydrogen-nitrogen separation membrane module to separate and obtain high-purity hydrogen gas.

[0012] Preferably, the ammonia-permeable membrane assembly is a palladium-based or palladium alloy ammonia-permeable membrane; the hydrogen-nitrogen separation membrane assembly is a molecular sieve membrane or a polymer separation membrane.

[0013] Preferably, during the ammonia synthesis reaction, the molar ratio of raw material hydrogen to nitrogen is 3:1, and the hydrogen is compressed to 5 MPa by the nitrogen-hydrogen compressor before being introduced into the dual-function reactor.

[0014] Preferably, during the ammonia synthesis reaction, the temperature of the bifunctional reactor is controlled at 400°C by an electric heater, and the space velocity of the feed gas is 3000 h⁻¹. -1 .

[0015] Preferably, during the ammonia decomposition reaction, the raw ammonia gas is compressed to 0.2 MPa by the circulating gas compressor and then introduced into the dual-function reactor.

[0016] Preferably, during the ammonia decomposition reaction, the temperature of the bifunctional reactor is controlled at 600°C by an electric heater, and the ammonia space velocity is 5000 h⁻¹. -1 .

[0017] Compared with the prior art, the technical solution of the present invention has the following advantages: A. Significantly improved catalyst versatility and reduced operating costs: The bifunctional catalyst of this invention utilizes La 1- x Sr x Sr doping on the AlO3 perovskite support enables the Ru active sites to simultaneously catalyze ammonia synthesis and decomposition, eliminating the need to disassemble the reactor and replace the catalyst. Experiments show that the catalyst exhibits ammonia synthesis activity comparable to conventional ruthenium-based catalysts at 400℃ / 10MPa (single-pass conversion 25% vs 22-24%), and an ammonia decomposition rate of 90% at 600℃ / 0.5MPa (higher than the 80-85% of conventional nickel-based catalysts). Furthermore, after 1000 hours of continuous operation, the Ru particles show no significant sintering (particle size remains 3-6nm), demonstrating excellent stability.

[0018] B. High degree of system integration, reducing equipment investment: This invention integrates the reaction, separation, and circulation units of ammonia synthesis and decomposition into one unit. Mode switching can be achieved simply by changing valves, eliminating the need for two separate systems. Calculations show that compared to traditional two systems, this system reduces equipment investment costs by 35-40%, reduces floor space by 50%, and avoids material transfer losses between the two systems (loss rate reduced from 5-8% to below 1%).

[0019] C. Improved reaction efficiency and economy: The system of this invention achieves efficient recovery of unreacted raw materials (H2 / N2 or NH3) by integrating the ammonia permeation membrane module with the circulating compressor. The total conversion rate of ammonia synthesis raw materials is increased from 20% in the traditional single pass to ≥90% (after circulation), and the ammonia decomposition rate reaches 90%. At the same time, the integrated design reduces the repeated energy consumption of the compression and heating units, and the comprehensive energy consumption per unit of ammonia is reduced by 20-25%, which significantly improves the economy of green ammonia energy storage. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the process of the dual-function reaction separation system of the present invention.

[0022] The diagram is labeled as follows: 1- Dual-function reactor; 2- Ammonia permeation membrane module; 3- Circulating gas compressor; 4- Nitrogen-hydrogen compressor; 5- Condenser; 6- Ammonia storage tank; 7- Hydrogen-nitrogen separation membrane module; K1 - First valve; K2 - Second valve; K3 - Third valve; K4 - Fourth valve; K5 - Fifth valve. Detailed Implementation

[0023] This invention can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the inventive concept to those skilled in the art. All other embodiments derived by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0024] like Figure 1As shown, this embodiment provides a reaction separation system for ammonia synthesis and decomposition. This system integrates a "dual-function reactor-membrane separation-circulation compression" unit, combined with a valve switching design, to achieve integrated operation of ammonia synthesis and decomposition. The specific structure is as follows: Dual-function reactor 1: Made of stainless steel, with a built-in electric heater (temperature control accuracy ±5℃), and filled with the above-mentioned dual-function catalyst. The reactor volume is designed according to the processing capacity. Ammonia permeation membrane module 2: It adopts a palladium-based or palladium alloy membrane (Pd-Ag alloy, Ag content 23wt%, membrane thickness 50μm), which has high ammonia selective permeation characteristics. The inlet is connected to the outlet of the bifunctional reactor 1 through a flange. Circulating gas compressor 3: an oil-free reciprocating compressor, the inlet of which is connected to the first interception side outlet of the ammonia permeation membrane module 2 and the tail gas outlet of the hydrogen-nitrogen separation membrane module 7 respectively, and the outlet is connected to the inlet of the dual-function reactor 1 through a pipeline for recycling unreacted raw materials. Nitrogen-hydrogen compressor 4: Diaphragm compressor, with its inlet connected to the N2 / H2 feed gas cylinder and its outlet connected to the inlet of the dual-function reactor 1, is used for pressurizing and transporting the feed gas in the ammonia synthesis mode; Condenser 5: Shell and tube condenser, the cooling medium is -5℃ ethylene glycol solution, the inlet is connected to the permeate side outlet of ammonia permeation membrane module 2, and it is used for the condensation and liquefaction of ammonia; Ammonia storage tank 6: Stainless steel pressure-resistant tank (design pressure 1.6MPa), the inlet is connected to the outlet of condenser 5, used for liquid ammonia storage; Hydrogen-nitrogen separation membrane module 7: It adopts a 13X molecular sieve membrane (pore size 0.56nm) or a polyimide polymer membrane, and its inlet is connected to the outlet of the second intercept side of the ammonia permeation membrane module 2, which is used for the separation of H2 and N2 in ammonia decomposition products; Valve group: including first valve (K1, outlet pipeline of circulating gas compressor), second valve (K2, outlet pipeline of first interception side of ammonia permeation membrane), third valve (K3, pipeline from permeation side of ammonia permeation membrane to circulating gas compressor), fourth valve (K4, pipeline from permeation side of ammonia permeation membrane to condenser), and fifth valve (K5, pipeline from second interception side of ammonia permeation membrane to hydrogen-nitrogen separation membrane), all of which are stainless steel shut-off valves (pressure resistance ≥16MPa).

[0025] The preparation and application of bifunctional catalysts are described in detail below with reference to specific embodiments. Example 1: Preparation of bifunctional catalysts

[0026] S1, synthesis of perovskite support (x=0.2, La) 0.8 Sr 0.2 AlO3): S1.1 Weigh out 4.336 g of La(NO3)3·6H2O, 0.522 g of Sr(NO3)2, and 3.751 g of Al(NO3)3·9H2O in a molar ratio of 0.8:0.2:1, dissolve them in 100 mL of deionized water, and stir until completely dissolved to form a solution with a total metal ion concentration of 0.1 mol / L. S1.2 Add citric acid (3.453g, molar ratio of metal ions to citric acid 1:1.5), adjust the pH to 3.5 with 1mol / L nitric acid, and stir for 30min until the solution is clear; S1.3 was stirred and evaporated in a constant temperature water bath at 80℃ until it became gel-like, and then dried at 120℃ for 12 hours to obtain a dry gel. The S1.4 dry gel was placed in a muffle furnace and heated to 700℃ at a rate of 5℃ / min, held at that temperature for 4 hours, cooled, and then ground through a 200-mesh sieve to obtain La. 0.8 Sr 0.2 AlO3 support (particle size 50 nm, X-ray diffraction confirmed as pure perovskite phase).

[0027] Loading and activation of S2 and Ru: S2.1 Weigh RuCl3·xH2O (0.121 g), dissolve it in 20 mL of anhydrous ethanol, and prepare a 0.03 mol / L RuCl3 ethanol solution; S2.2 Take 5g of La 0.8 Sr 0.2 The AlO3 support was impregnated in the above solution, sonicated at 300W for 1 hour, and stirred at room temperature for 24 hours. The solid was collected by filtration, dried under vacuum at 80℃ for 6 hours, transferred to a tube furnace, and H2 was introduced at 50 mL / min. The temperature was increased to 450℃ at 5℃ / min and kept at this temperature for 2 hours for reduction. After cooling, a bifunctional catalyst was obtained. ICP-MS showed that the Ru loading was 3 wt%, and transmission electron microscopy showed that the Ru nanoparticle size was 4-5 nm. Example 2: Operation of a bifunctional reaction separation system (ammonia synthesis mode)

[0028] System check: Confirmed that the bifunctional reactor 1 is filled with the catalyst prepared in Example 1 (500 mL), the ammonia permeation membrane module 2 is a Pd-Ag alloy membrane, and the ammonia separation membrane module 7 is a 13X molecular sieve membrane. Valve settings: Open K1, K2, and K4; Close K3 and K5. Raw material introduction: H2 / N2 (3:1, molar ratio) is compressed to 5MPa by nitrogen-hydrogen compressor 4 and then introduced into bifunctional reactor 1; Reaction control: The electric heater is heated to 400℃, and the feed gas flow rate is adjusted to maintain a space velocity of 3000 h⁻¹. -1 ; Product collection: NH3 from the permeate side of the ammonia membrane is condensed by condenser 5 and enters ammonia storage tank 6. The purity of liquid ammonia is 99.9% after sampling and testing. The primary conversion rate of raw material gas can reach 25%. Unreacted H2 / N2 is returned to the dual-function reactor 1 via circulating gas compressor 3. After 24 hours of continuous operation, the total conversion rate of raw material gas reaches 91%. Example 3: Operation of a bifunctional reaction separation system (ammonia decomposition mode)

[0029] Valve switching: Open K1, K3, and K5; Close K2 and K4. Raw material introduction: Liquid ammonia in ammonia storage tank 6 evaporates into ammonia gas, which is then compressed to 0.2 MPa by circulating gas compressor 3 and introduced into dual-function reactor 1; Reaction control: The electric heater is heated to 600℃, and the ammonia flow rate is adjusted to maintain a space velocity of 5000 h⁻¹. -1 ; Product separation: Unreacted NH3 on the permeate side of the ammonia permeate membrane is returned to the bifunctional reactor 1 via the recirculating gas compressor 3, while the H2 / N2 mixed gas on the retrieval side enters the hydrogen-nitrogen separation membrane module 7. Product testing: The purity of H2 at the outlet of the ammonia separation membrane was 99.99% after sampling and testing. After 24 hours of continuous operation, the ammonia decomposition rate remained stable at 90%. Comparative Example: Operation of Two Traditional Independent Systems

[0030] Ammonia synthesis system: using a conventional ruthenium-based catalyst (Ru / carbon support), fixed-bed reactor, 5 MPa / 400℃, H2 / N2=3:1, space velocity 3000 h⁻¹ -1 The liquid ammonia has a purity of 99.8%, a total raw material conversion rate of 88%, and an equipment investment of 2 million yuan. Ammonia decomposition system: using a nickel-based catalyst (Ni / Al2O3), fixed-bed reactor, 0.2 MPa / 600℃, space velocity 5000 h⁻¹ -1 The H2 purity is 99.9%, the ammonia decomposition rate is 84%, and the equipment investment is 1.8 million yuan. Comparison results: The total investment of the two traditional systems is 3.8 million yuan, while the investment of the system of this invention is 2.2 million yuan (a reduction of 42%); the H2 purity and ammonia decomposition rate of this invention are 3.4% and 7.1% higher than those of the traditional system, respectively, and the overall energy consumption is reduced by 23%.

[0031] The above embodiments demonstrate that the bifunctional catalyst and reaction separation system of the present invention can stably achieve flexible switching between ammonia synthesis and decomposition, and is superior to the prior art in terms of catalyst activity, system economy, and product purity, fully meeting the practical application requirements of green ammonia energy storage and hydrogen energy conversion.

[0032] Any aspects not described in this invention are applicable to existing technologies.

[0033] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A bifunctional catalyst for ammonia synthesis and decomposition, characterized in that, The bifunctional catalyst is a ruthenium-based catalyst, with Ru nanoparticles as its active component, supported on a perovskite support. The perovskite support has the general chemical formula La. 1- x Sr x AlO3, wherein 0.2≤x≤0.3, Ru loading is 2-4wt%, and particle size is 3-6nm.

2. The bifunctional catalyst according to claim 1, characterized in that, The preparation method of the bifunctional catalyst includes the following steps: S1, perovskite support synthesis S1.1 Weigh out La(NO3)3·6H2O, Sr(NO3)2, and Al(NO3)3·9H2O in deionized water at a molar ratio of (1-x):x:1, where 0.2≤x≤0.3, to form a mixed solution with a total metal ion concentration of 0.1mol / L; S1.2 Add citric acid to the mixed solution, wherein the molar ratio of metal ions to citric acid is 1:1.5, adjust the pH of the solution to 3-4, and stir until clear; S1.

3. The clarified solution is evaporated and concentrated at 80°C to a gel state, and then dried at 110-120°C for 12-16 hours to obtain a dry gel. S1.

4. Place the dried gel in a muffle furnace, raise the temperature to 700-750℃ at a rate of 5℃ / min, and hold for 4-6 hours. After cooling, obtain La. 1-x Sr x AlO3 perovskite support; Loading and activation of S2 and Ru S2.1 Weigh RuCl3·xH2O and dissolve it in anhydrous ethanol to prepare a RuCl3 ethanol solution with a concentration of 0.02-0.05 mol / L; S2.2, Take the La obtained in step S1 1-x Sr x An AlO3 perovskite support is impregnated in a RuCl3 ethanol solution, sonicated for 1 hour, and then stirred at room temperature for 20-24 hours. After filtration, the solid product is vacuum dried at 80°C for 6-8 hours, and then placed in an H2 atmosphere. The temperature is increased to 350-450°C at a rate of 5°C / min and kept at this temperature for 2-3 hours to form a bifunctional catalyst with Ru nanoparticles of 3-6 nm in diameter supported on the surface of the perovskite support.

3. The bifunctional catalyst according to claim 2, characterized in that, The concentration of the RuCl3 ethanol solution in step S2.1 is 0.03 mol / L.

4. The bifunctional catalyst according to claim 2, characterized in that, In step S2.2, the H2 flow rate of the H2 atmosphere is 50-60 mL / min, the heating rate is increased to 450℃ and the temperature is maintained for reduction for 2-3 hours.

5. A bifunctional reaction separation system for ammonia synthesis and decomposition, characterized in that, include: A bifunctional reactor (1) is filled with a bifunctional catalyst as described in any one of claims 1-4 that can simultaneously catalyze ammonia synthesis and ammonia decomposition reactions; The ammonia-permeable membrane module (2) has its inlet connected to the outlet of the bifunctional reactor (1); The inlet of the circulating gas compressor (3) is connected to the first truncation side outlet of the ammonia permeation membrane assembly (2), and its outlet is connected to the inlet of the dual-function reactor (1); The nitrogen-hydrogen compressor (4) has its inlet connected to the raw material gas and its outlet connected to the dual-function reactor (1), and is used to supply hydrogen and nitrogen raw materials to the dual-function reactor (1) in ammonia synthesis mode; The condenser (5) has its inlet connected to the permeate side outlet of the ammonia-permeable membrane assembly (2); The ammonia storage tank (6) has its inlet connected to the outlet of the condenser (5); The hydrogen-nitrogen separation membrane assembly (7) has its inlet connected to the second truncation side outlet of the ammonia permeation membrane assembly (2) and is used to separate hydrogen and nitrogen in ammonia decomposition mode; And multiple valves are used to switch the system's operation between ammonia synthesis mode and ammonia decomposition mode.

6. The bifunctional reaction separation system according to claim 5, characterized in that, The outlet pipe of the circulating gas compressor (3) is provided with a first valve (K1), the outlet pipe of the ammonia permeation membrane assembly (2) is provided with a second valve (K2) on the first interception side and a fifth valve (K5) on the second interception side. The outlet pipe of the ammonia permeation membrane assembly (2) is divided into two paths. One path is provided with a fourth valve (K4) connected to the condenser (5), and the other path is provided with a third valve (K3) connected to the inlet of the circulating gas compressor (3). When the system performs an ammonia synthesis reaction: the first valve (K1), the second valve (K2), and the fourth valve (K4) are opened, and the third valve (K3) and the fifth valve (K5) are closed. The mixture of raw material hydrogen and nitrogen is compressed by the nitrogen-hydrogen compressor (4) and enters the bifunctional reactor (1). Under the action of the bifunctional catalyst, an ammonia synthesis reaction occurs. The reaction products enter the ammonia permeation membrane module (2). Unreacted nitrogen and hydrogen flow out from the first interception side of the ammonia permeation membrane module (2), are compressed by the circulating gas compressor (3), and return to the inlet of the bifunctional reactor (1) to continue participating in the reaction. Ammonia flows out from the permeation side of the ammonia permeation membrane module (2), is condensed by the condenser (5), and stored in the ammonia storage tank (8). When the system performs ammonia decomposition reaction: valves 1 (K1), 3 (K3), and 5 (K5) are opened, and valves 2 (K2) and 4 (K4) are closed. The raw material ammonia gas is compressed by the circulating gas compressor (3) and then permeates into the dual-function reactor (1). Under the action of the dual-function catalyst, the ammonia decomposition reaction occurs. The reaction products enter the ammonia permeation membrane module (2). The unreacted ammonia gas flows out from the permeation side of the ammonia permeation membrane module (2), is compressed by the circulating gas compressor (3), and returns to the inlet of the dual-function reactor (1) to continue participating in the reaction. The nitrogen and hydrogen mixed gas produced by the decomposition flows out from the second interception side of the ammonia permeation membrane module (2) and enters the hydrogen-nitrogen separation membrane module (7) to separate and obtain high-purity hydrogen gas.

7. The bifunctional reaction separation system according to claim 5, characterized in that, The ammonia-permeable membrane assembly (2) uses a palladium-based or palladium alloy ammonia-permeable membrane; the ammonia separation membrane assembly (7) uses a molecular sieve membrane or a polymer separation membrane.

8. The bifunctional reaction separation system according to claim 6, characterized in that, When the ammonia synthesis reaction is carried out, the molar ratio of the raw material hydrogen to nitrogen is 3:

1. After being compressed to 5MPa by the nitrogen-hydrogen compressor (4), it is introduced into the dual-function reactor (1).

9. The bifunctional reaction separation system according to claim 6, characterized in that, During the ammonia synthesis reaction, the temperature of the bifunctional reactor (1) is controlled at 400°C by an electric heater, and the space velocity of the feed gas is 3000 h⁻¹. -1 .

10. The bifunctional reaction separation system according to claim 6, characterized in that, During the ammonia decomposition reaction, the raw material ammonia gas is compressed to 0.2 MPa by the circulating gas compressor (3) and then introduced into the dual-function reactor (1).

11. The bifunctional reaction separation system according to claim 6, characterized in that, During the ammonia decomposition reaction, the temperature of the bifunctional reactor (1) is controlled at 600°C by an electric heater, and the ammonia space velocity is 5000 h⁻¹. -1 .

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