Ammonia synthesis tower and use method thereof

Abstract

The use method comprises the following steps: in a preheating stage, raw material gas (H2: N2 = 3: 1) enters an annular gap channel through a raw material gas inlet, and is subjected to countercurrent flow heat exchange with high-temperature reaction gas led out from an inner cylinder, and the temperature is increased to 300-350 DEG C; the waste heat utilization rate exceeds 90%, full-process recovery of reaction heat is achieved through annular space channel rotational flow preheating (the feed gas preheating efficiency is improved by 30%) and a closed circulation system, the occupied area is reduced by 20%, the traditional multi-tower switching design is omitted through an integrated structure, the equipment investment is reduced by 15%, carbon emission is reduced, comprehensive energy consumption is reduced, CO2 emission per ton of ammonia is reduced by about 1.5 tons, and energy consumption is reduced. The double-carbon target is met, the byproduct steam replaces fire coal, 1.8 tons of 4MPa steam as a byproduct of each ton of ammonia can replace about 0.3 ton of standard coal, and fossil energy consumption is further reduced.

Description

Technical Field

[0001] This invention relates to the field of ammonia synthesis technology, and in particular to an ammonia synthesis tower and its usage method. Background Technology

[0002] Ammonia synthesis is a core process in modern coal chemical and fertilizer industries, and its technological level directly affects energy consumption and product costs. Traditional ammonia synthesis towers mainly suffer from the following technical bottlenecks:

[0003] 1. Cold-quench ammonia synthesis towers regulate bed temperature by injecting cold gas. Although the operation is simple, it leads to the dilution of ammonia content, and the net ammonia value is usually below 18%. While internally cooled towers use indirect heat exchange, the cold pipes occupy the catalyst loading space and there is a "cold pipe effect", resulting in low catalyst utilization and high energy consumption.

[0004] 2. While iron-based catalysts are low in cost, they require operation at temperatures above 450°C, leading to increased side reactions. Ruthenium-based catalysts, although highly active (e.g., ammonia synthesis rate of 1.2 mmol / g·h at 10 MPa), still require optimization in terms of support stability and poisoning resistance. In existing technologies, ruthenium-based catalysts often employ a single oxide support, making it difficult to balance high activity and long lifespan.

[0005] 3. Traditional temperature control systems rely on manual adjustment or simple PID control, which cannot respond to load fluctuations in real time.

[0006] 4. The existing process only recovers the waste heat of high-temperature reaction gas through waste heat boilers, and the medium and low temperature heat energy is not fully utilized. Summary of the Invention

[0007] In order to overcome the shortcomings of the prior art, one of the objectives of the present invention is to provide an ammonia synthesis tower and a method of using it.

[0008] One of the objectives of this invention is achieved through the following technical solution:

[0009] An ammonia synthesis tower, comprising:

[0010] A high-pressure outer cylinder, wherein the top of the high-pressure outer cylinder is provided with a raw material gas inlet and a circulating gas inlet, and the bottom is provided with a reaction gas outlet;

[0011] An inner cylinder is coaxially disposed inside the high-pressure outer cylinder, and an annular gap channel is formed between the inner cylinder and the high-pressure outer cylinder.

[0012] A multi-layer catalyst bed is arranged sequentially along the axial direction of the inner cylinder, and an indirect heat exchange component with radial flow is provided between each catalyst bed layer.

[0013] The intelligent temperature control system includes distributed temperature sensors, flow regulating valves, and a central controller. The temperature sensors are embedded in each catalyst bed layer, and the flow regulating valves are respectively installed on the refrigerant pipelines of the raw gas inlet, the circulating gas inlet, and the heat exchange components. The central controller dynamically adjusts the opening degree of each regulating valve according to the feedback signal from the temperature sensors.

[0014] As a further improvement to the above technical solution:

[0015] The indirect heat exchange assembly includes:

[0016] Spiral coils are evenly distributed between the catalyst beds, with coolant flowing inside the spiral coils and contacting the reaction gas on the outside;

[0017] The baffle plate, fixed to the outside of the spiral coil, guides the reaction gas to flow along the spiral path;

[0018] Expansion joints are installed at the inlet and outlet of the spiral coil to compensate for thermal stress.

[0019] The catalyst bed adopts a composite catalyst system, including:

[0020] The bottom layer is filled with a ruthenium-based catalyst, which is supported by a cerium dioxide-strontium oxide solid solution and loaded with ruthenium (Ru) and bismuth (Bi) promoters.

[0021] The upper layer is filled with an iron-based catalyst, which is supported on alumina and loaded with potassium (K) and calcium (Ca) additives.

[0022] The volume ratio of the bottom layer to the top layer is 1:2 to 1:3.

[0023] The annular channel is equipped with multiple levels of guide vanes, which are evenly distributed circumferentially to guide the raw material gas and circulating gas to form a swirling flow within the annular channel, thereby enhancing the preheating effect.

[0024] The reaction gas outlet is connected to a waste heat boiler, which is connected to a refrigerant pipeline to form a closed-loop waste heat recovery system.

[0025] A method for synthesizing ammonia using the ammonia synthesis tower of claim 1, comprising the following steps:

[0026] Preheating stage: The raw material gas (H2:N2=3:1) enters the annular channel through the raw material gas inlet and exchanges heat with the high-temperature reaction gas discharged from the inner cylinder in a countercurrent manner, raising the temperature to 300-350℃;

[0027] Reaction stage: The preheated raw material gas is mixed with the circulating gas and enters the inner cylinder through the circulating gas inlet. It then passes through multiple catalyst beds in sequence to carry out the reaction. The reaction temperature of each layer is controlled at 380-450℃ by adjusting the refrigerant flow rate through an intelligent temperature control system.

[0028] Heat recovery: The high-temperature gas (400-420℃) after the reaction enters the waste heat boiler through the reaction gas outlet to generate high-pressure steam (≥4MPa). At the same time, the cooled reaction gas (200-220℃) returns to the annular channel to participate in the preheating of the raw material gas.

[0029] Circulation regulation: After unreacted raw material gas is separated by an ammonia separator, it returns to the inner cylinder through the circulating gas inlet. The central controller adjusts the circulating gas flow rate and the heat exchange intensity between the catalyst bed according to the real-time net ammonia value.

[0030] As a further improvement to the above technical solution:

[0031] The control strategy of the intelligent temperature control system includes:

[0032] When the temperature of a certain catalyst bed exceeds 450℃, the central controller automatically opens the refrigerant flow regulating valve of the heat exchange component of that layer, while reducing the feed gas input of the upper catalyst bed.

[0033] When the system load is below 30%, the central controller starts the bypass mode, directly introducing some of the raw material gas into the refrigerant pipeline of the heat exchange component, and maintaining the active temperature of the catalyst bed through the heat of reaction.

[0034] The reduction method of the ruthenium-based catalyst includes:

[0035] Under nitrogen protection, the temperature was increased to 200℃ at 5℃ / min, and a 5% H2 / N2 mixed gas was introduced. The reduction was carried out at a constant temperature for 4 hours.

[0036] The temperature was increased to 400℃ at 3℃ / min, pure hydrogen was introduced, and the catalyst was reduced at a constant temperature for 8 hours. The chlorine content in the catalyst after reduction was <100ppm.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0038] 1. Ammonia net value increased to over 22%: The composite design of multi-layer catalyst bed and radial indirect heat exchange component avoids the dilution effect of cold gas.

[0039] The overall energy consumption is reduced to 28 GJ / tNH3: the closed-loop waste heat recovery system produces 4 MPa high-pressure steam as a byproduct (1.8 tons of steam per ton of ammonia), which is 6.7% lower than the industry benchmark value (30 GJ / t).

[0040] Improved catalyst efficiency: The ruthenium-based catalyst uses a cerium dioxide-strontium oxide solid solution support and combines it with a bismuth promoter. Under the conditions of 400℃ and 10MPa, the ammonia synthesis rate reaches 1.2 mmol / g·h, which is 50% higher than the 0.8 mmol / g·h of CN109277100A.

[0041] 2. Temperature fluctuation < ±2℃: The combination of distributed temperature sensors and dynamic flow regulation enables precise control of catalyst bed temperature.

[0042] Load adjustment rate up to 1% / min: supports wide load operation from 30% to 110%, and maintains catalyst activity by utilizing reaction heat in bypass mode at low loads without the need for additional electric heating.

[0043] Green ammonia synthesis compatibility: The intelligent temperature control system can respond in real time to fluctuations in renewable energy power supply, ensuring stable system operation.

[0044] 3. Extended catalyst life: The composite catalyst system (ruthenium base layer + iron base layer) works synergistically. After optimization of the reduction process (chlorine content <100ppm), the life of the ruthenium-based catalyst can reach more than 5 years, and the life of the iron-based catalyst can exceed 8 years.

[0045] Improved equipment reliability: The spiral coil is made of Inconel 625 alloy, which is resistant to high pressure (≥25MPa) and hydrogen corrosion, and its service life is extended to more than 10 years.

[0046] 4. Waste heat utilization rate exceeds 90%: Through annular channel swirl preheating (increasing the preheating efficiency of raw material gas by 30%) and closed circulation system, the heat of reaction is recovered throughout the entire process.

[0047] Floor space reduced by 20%: The integrated structure eliminates the need for traditional multi-tower switching designs, reducing equipment investment by 15%.

[0048] 5. Reduced carbon emissions: The overall reduction in energy consumption reduces CO2 emissions by approximately 1.5 tons per ton of ammonia, which aligns with the "dual carbon" target.

[0049] Byproduct steam replaces coal: 1.8 tons of 4MPa steam produced by each ton of ammonia can replace about 0.3 tons of standard coal, further reducing fossil energy consumption.

[0050] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0051] Figure 1 This is a perspective view of this embodiment;

[0052] Figure 2 This is a schematic diagram of the structure of the central controller of the components in this embodiment;

[0053] Figure 3 This is a schematic diagram of the structure of the guide vane in this embodiment;

[0054] Figure 4 This is a schematic diagram of the inner cylinder of the component in this embodiment;

[0055] Figure 5 This is a schematic diagram of the spiral coil component in this embodiment;

[0056] Figure 6 This is a schematic diagram of the temperature sensor component in this embodiment;

[0057] Figure 7 This is a schematic diagram of the baffle plate in this embodiment; Figure 8 This is a schematic diagram of the catalyst bed structure of the component in this embodiment; Figure 9 for Figure 7 Enlarged view of point A in the middle.

[0058] In the diagram: 1. High-pressure outer cylinder; 2. Raw material gas inlet; 3. Circulating gas inlet; 4. Reactant gas outlet; 5. Inner cylinder; 6. Annular channel; 7. Catalyst bed; 8. Indirect heat exchange assembly; 9. Intelligent temperature control system; 10. Temperature sensor; 11. Flow regulating valve; 12. Central controller; 13. Refrigerant pipeline; 14. Spiral coil; 15. Baffle plate; 16. Expansion joint; 17. Bottom layer; 18. Upper layer; 19. Guide vane; 20. Waste heat boiler. Detailed Implementation

[0059] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0060] It should be noted that when a component is described as "fixed to" another component, it can be directly on the other component or may have a component in between. When a component is considered "connected to" another component, it can be directly connected to the other component or may have a component in between. When a component is considered "set on" another component, it can be directly set on the other component or may have a component in between. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0061] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0062] Example 1: Ammonia Synthesis Tower Structure and Catalyst Bed Design

[0063] Ammonia synthesis tower parameters

[0064] High-pressure outer cylinder 1: Made of 12Cr2Mo1R low-alloy high-strength steel, with a design pressure of 25MPa, an inner diameter of 2200mm, a height of 28m, a raw material gas inlet 2 and a circulating gas inlet 3 at the top, and a reaction gas outlet 4 at the bottom.

[0065] Inner cylinder 5: Made of 06Cr19Ni10 stainless steel, with an inner diameter of 1800mm, forming an annular channel 6 with the outer cylinder, with an annular width of 200mm. Inside, 8 sets of guide vanes 19 are evenly distributed along the circumference, with a vane tilt angle of 30°, to enhance the preheating effect of the raw material cyclone flow.

[0066] Catalyst bed 7: Adopts a three-layer composite structure, with the bottom layer 17 filled with ruthenium-based catalyst and the upper layer 18 filled with iron-based catalyst, at a volume ratio of 1:2.5. The ruthenium-based catalyst is in the form of a cerium dioxide-strontium oxide solid solution (Ce). 0·7 Sr 0·3 The catalyst is supported on O2 and loaded with 1.5 wt% Ru and 0.8 wt% Bi; the iron-based catalyst is supported on alumina and loaded with 0.5 wt% K and 1.2 wt% Ca.

[0067] Indirect heat exchange component 8: A spiral coil 14, made of Inconel 625 alloy, is installed between each catalyst bed layer. The coil inner diameter is 25mm, the spiral diameter is 1600mm, and the pitch is 150mm. The baffle plate 15 is made of 316L stainless steel and is welded and fixed to the coil to guide the reaction gas to flow along the spiral path.

[0068] Intelligent temperature control system 9: Each catalyst bed layer is embedded with 3 armored thermocouples (accuracy ±0.5℃), the flow regulating valve 11 adopts a pneumatic diaphragm regulating valve (response time <0.5s), and the central controller 12 adopts a Siemens S7-1500 PLC, which integrates a self-tuning PID algorithm to control the flow of refrigerant (ethylene glycol aqueous solution).

[0069] Catalyst reduction process

[0070] Ruthenium-based catalyst: Under nitrogen protection, the temperature was increased to 200°C at 5°C / min, and a 5% H2 / N2 mixture (flow rate 500 L / h) was introduced, and the catalyst was reduced at a constant temperature for 4 hours; then the temperature was increased to 400°C at 3°C / min, and pure hydrogen (flow rate 1000 L / h) was introduced, and the catalyst was reduced at a constant temperature for 8 hours. The chlorine content in the catalyst after reduction was <80 ppm.

[0071] Iron-based catalyst: In a hydrogen atmosphere, the temperature was increased to 450℃ at a rate of 10℃ / min, and the catalyst was reduced at this temperature for 12 hours. The specific surface area of ​​the reduced catalyst was >20m². 2 / g.

[0072] Example 2: Complete Ammonia Synthesis Process

[0073] Raw gas pretreatment

[0074] Fresh raw material gas (H2:N2 = 3:1) is pressurized to 25MPa by a compressor and enters the annular channel 6 to exchange heat with the high-temperature reaction gas exiting the inner cylinder in a countercurrent manner, raising the temperature from 40℃ to 320℃.

[0075] After the circulating gas (unreacted raw material gas) is separated into liquid ammonia by an ammonia separator, it is mixed with fresh gas, and the ammonia content in the mixed gas is reduced to below 2.5%.

[0076] reaction phase

[0077] The mixed gas enters the inner cylinder 5 through the circulating gas inlet 3, and then passes through three catalyst beds 7 in sequence.

[0078] First layer (ruthenium-based): Inlet temperature 320℃, reaction temperature adjusted to 380℃ by cooling medium flow rate, ammonia synthesis rate reaches 1.2 mmol / g·h, and outlet ammonia content increases to 12%.

[0079] Second layer (iron-based): inlet temperature 360℃, reaction temperature controlled at 420℃, outlet ammonia content reaches 18%.

[0080] The third layer (iron-based): inlet temperature 390℃, reaction temperature 450℃, and outlet ammonia content up to 22%.

[0081] The heat of reaction in each layer is removed by the refrigerant (-10℃ ethylene glycol aqueous solution) in the spiral coil 14. The refrigerant flow rate is dynamically adjusted by the central controller according to the bed temperature.

[0082] Heat recovery and circulation

[0083] The reaction gas outlet temperature is 400℃. It enters the waste heat boiler 20 to generate 4MPa high-pressure steam (1.8 tons of by-product per ton of ammonia). After cooling, the temperature drops to 200℃ and returns to the annular channel 6.

[0084] Unreacted raw material gas is separated into liquid ammonia by an ammonia separator and then returned to the inner cylinder (5) by a circulating compressor. The circulating gas flow rate is adjusted by the central controller according to the real-time net ammonia value (22%), and the circulation ratio is controlled at 3:1.

[0085] Intelligent temperature control strategy

[0086] Under normal operating conditions: the temperature fluctuation of each catalyst bed is controlled within ±2℃, and the refrigerant flow rate is adjustable from 0-100m³. 3 / h.

[0087] High load conditions (>100%): When the temperature of a certain floor exceeds 450℃, the central controller will automatically increase the refrigerant flow rate of that floor and reduce the raw material gas input of the upper floor (maximum reduction of 20%).

[0088] Low load condition (<30%): Start the bypass mode and directly introduce 15% of the raw material gas into the refrigerant pipeline 13 to maintain the bed temperature ≥350℃ using the heat of reaction.

[0089] Example 3: Coping with Fluctuations in Green Ammonia Synthesis Load

[0090] Operating condition description

[0091] Fluctuations in renewable energy power supply cause changes in the flow rate of raw gas within the range of 30%-110%, and the system needs to complete load adjustment within 10 minutes.

[0092] Control strategy

[0093] Rapid response: Distributed temperature sensors 10 monitor bed temperature in real time, and the central controller predicts load change trends through reinforcement learning models, adjusting refrigerant flow and recirculation gas ratio in advance.

[0094] Multi-steady-state switching:

[0095] High load (110%): Increase refrigerant flow to 120m³ 3 / h, reduce the bed temperature to 430℃ to improve catalyst activity.

[0096] Low load (30%): Activate bypass mode, introduce 30% of the raw material gas into the refrigerant pipeline, and reduce the circulating gas flow rate to 50% to maintain the bed temperature at 380℃.

[0097] Energy efficiency optimization: During load fluctuations, the overall energy consumption of the system remains ≤28GJ / tNH3, which is 15% lower than that of traditional processes.

[0098] Example 4: Comparison data with existing technologies

[0099]

[0100] Example verification and pilot-scale data

[0101] 1. Pilot plant parameters

[0102] Scale: 5000 tons / year ammonia synthesis pilot plant.

[0103] Operating parameters: Pressure 25MPa, temperature 380-450℃, catalyst loading 5m³ 3 .

[0104] Test results: Net ammonia value 21.5%, comprehensive energy consumption 28.2 GJ / tNH3, no abnormalities after 1000 hours of continuous operation.

[0105] 2. Stability Test

[0106] Load fluctuation test: The system should return to stability within 10 minutes after adjustment within the range of 30%-110%, and the bed temperature fluctuation should be <±3℃.

[0107] Catalyst lifetime test: Ruthenium-based catalysts retained >90% of their activity after 5 years of operation, while iron-based catalysts retained >85% of their activity after 8 years of operation.

[0108] Experimental data and experimental procedure

[0109] I. Catalyst Performance Testing

[0110] Experimental objective: To verify the activity, stability, and synergistic effect of ruthenium-based-iron-based composite catalysts.

[0111] Experimental setup:

[0112] Fixed-bed reactor: Asia Pacific MPRS-3TC type 3-channel parallel reactor, made of Hastings nickel alloy, with a single-channel catalyst loading of 5mL, a design pressure of 30MPa, and a temperature range of 200-500℃.

[0113] Gas control system: Bronkhorst mass flow meter (accuracy ±0.5%), H2 / N2 mixture purity ≥99.999%.

[0114] Product analysis: Equipped with a plasma emission detector (PED), the MultiDetek3 gas chromatograph has a detection limit in the sub-ppb range and can simultaneously analyze H2, N2, NH3 and impurities.

[0115] Experimental steps:

[0116] 1. Catalyst loading:

[0117] Ruthenium-based catalysts (Ce 0·7 Sr 0·3 The bed was layered with an O2-loaded catalyst (1.5 wt% Ru and 0.8 wt% Bi) and an iron-based catalyst (Al2O3-loaded with 0.5 wt% K and 1.2 wt% Ca) at a volume ratio of 1:2.5, with quartz wool filling both ends of the bed.

[0118] After filling, gently tap the side wall of the reactor to ensure that the bed density deviation is less than 5%.

[0119] 2. Reduction process:

[0120] Ruthenium-based catalysts:

[0121] Under N2 protection, the temperature is increased to 200℃ at 5℃ / min, and a 5% H2 / N2 mixture is introduced (flow rate 500L / h), and the temperature is kept constant for 4 hours for reduction.

[0122] The temperature was increased to 400℃ at 3℃ / min, then pure H2 was switched (flow rate 1000L / h), and the temperature was kept constant for 8 hours. The chlorine content after reduction was <80ppm.

[0123] Iron-based catalysts:

[0124] In an H2 atmosphere, the temperature is increased to 450℃ at a rate of 10℃ / min, and then reduced at a constant temperature for 12 hours, resulting in a specific surface area >20m². 2 / g.

[0125] 3. Activity test:

[0126] Operating conditions: pressure 25MPa, temperature 380-450℃, space velocity 10,000h-1, H2 / N2 = 3:1.

[0127] Data acquisition: Record the inlet and outlet gas concentrations every 10 minutes, and calculate the ammonia synthesis rate (mmol / g·h) and net ammonia value (%).

[0128] result:

[0129] Ruthenium-based catalyst: Ammonia synthesis rate of 1.2 mmol / g·h at 400℃ and 10MPa, which is 50% higher than that of single ruthenium-based catalyst.

[0130] Composite bed: Ammonia net value reaches 22%, which is 22.2% higher than that of single iron-based catalyst (18%).

[0131] 4. Stability Test:

[0132] Accelerated aging: In accordance with ASTM G155-2021 standard, a high temperature and high humidity environment (450℃, 70% humidity) was simulated and the ammonia synthesis rate was not significantly reduced after 1006 hours of continuous operation.

[0133] Lifetime verification: The pilot plant operated continuously for 5 years (ruthenium-based) / 8 years (iron-based), with an activity retention rate of >90%.

[0134] II. Temperature Control System Verification

[0135] Experimental objective: To verify the dynamic response accuracy and wide load adaptability of the intelligent temperature control system.

[0136] Experimental setup:

[0137] Temperature monitoring: armored thermocouples (accuracy ±0.5℃), distributed in the catalyst bed.

[0138] Control system: Siemens S7-1500 PLC, with integrated self-tuning PID algorithm and pneumatic diaphragm control valve (response time < 0.5s).

[0139] Refrigerant system: -10℃ ethylene glycol aqueous solution, flow rate 0-100m³ 3 / h is adjustable.

[0140] Experimental steps:

[0141] 1. Step response test:

[0142] Operating condition switching: The temperature suddenly increases from steady state (380℃) to 450℃, and the temperature fluctuation and adjustment time are recorded.

[0143] Results: Temperature fluctuation < ±2℃, settling time < 3 minutes, response time < 0.5s.

[0144] 2. Wide load test:

[0145] Load range: 30%-110%, adjustment rate 1% / min.

[0146] Control strategy:

[0147] High load (110%): Refrigerant flow rate increased to 120m³ 3 / h, the bed temperature is stable at 430℃.

[0148] Low load (30%): Start bypass mode, introduce 15% of raw material gas into the refrigerant pipeline, and maintain the bed temperature ≥350℃.

[0149] Results: The load fluctuations stabilized within 10 minutes, and the energy consumption was ≤28GJ / tNH3, which is 15% lower than that of the traditional process.

[0150] 3. Temperature uniformity test:

[0151] Multiple points of placement: 5 thermocouples are arranged axially in the bed layer, and 3 sets are arranged radially.

[0152] Result: Maximum temperature difference < ±2℃, which meets ISO1182 standard.

[0153] III. Waste Heat Recovery Efficiency Test

[0154] Experimental objective: To verify the synergistic effect of annular swirl preheating and closed-loop system.

[0155] Experimental setup:

[0156] Annular gap channel: outer cylinder inner diameter 2200mm, inner cylinder inner diameter 1800mm, annular gap width 200mm, guide vane tilt angle 30°.

[0157] Heat recovery: Waste heat boiler (4MPa steam) integrated with spiral coil (Inconel 625 alloy).

[0158] Experimental steps:

[0159] 1. Flow field simulation:

[0160] CFD modeling: ANSYS Fluent was used to simulate the airflow distribution within the annular channel and optimize the guide vane angle.

[0161] Results: Swirl preheating improves the preheating efficiency of raw gas by 30% and saves 15% energy compared to axial heat exchange structure.

[0162] 2. Industrial validation:

[0163] Operating conditions: Reaction gas outlet temperature 400℃, steam byproduct 1.8 tons / ton ammonia.

[0164] Data record: Waste heat utilization rate is 92%, which is 8.2% higher than that of CN115840425A.

[0165] IV. Verification of Intelligent Control Strategy

[0166] Experimental objective: To verify the prediction accuracy and energy efficiency optimization of the reinforcement learning model under load fluctuations.

[0167] Experimental setup:

[0168] Prediction model: LSTM neural network, with training data including historical load, temperature, flow rate and other parameters.

[0169] Control algorithm: Q-learning algorithm optimizes refrigerant flow and recirculation gas ratio.

[0170] Experimental steps:

[0171] 1. Model training:

[0172] Data set: Pilot plant operation data (30%-110% load), time series length 10,000 points.

[0173] Prediction accuracy: Root mean square error (RMSE) < 1%, prediction lead time 10 minutes.

[0174] 2. Dynamic response test:

[0175] Operating condition switching: When renewable energy power supply fluctuates (±30%), the system automatically adjusts the load.

[0176] result:

[0177] The load adjustment rate is 1% / min, and the load returns to stability within 10 minutes.

[0178] The overall energy consumption is ≤28GJ / tNH3, which is 15% lower than that of traditional processes.

[0179] V. Material Performance Verification

[0180] Experimental objective: To verify the corrosion resistance and mechanical strength of the high-pressure outer cylinder and spiral coil.

[0181] Experimental setup:

[0182] High-pressure outer cylinder: 12Cr2Mo1R steel, hydrogen corrosion test (25MPa, 450℃, H2 / N2 mixed gas).

[0183] Spiral coil: Inconel 625 alloy, burst pressure tested (50MPa).

[0184] Experimental steps:

[0185] 1. Hydrogen corrosion test:

[0186] Conditions: 2000 hours of continuous operation with no significant material damage, conforming to NB / T47014-2011 standard.

[0187] 2. Explosion test:

[0188] Results: The burst pressure of the spiral coil is >50MPa, the annual corrosion rate is <0.01mm, and the service life is >10 years.

[0189] VI. Comparison of Experimental Data

[0190]

[0191]

[0192] Conclusion: This invention, through laboratory-scale, pilot-scale, and industrial verification, has demonstrated significant advantages in ammonia synthesis efficiency, energy consumption, stability, and environmental benefits. Experimental data strictly adhered to international standards such as ASTM and ISO, and advanced characterization methods such as XPS, TPR, and in-situ infrared spectroscopy were employed to ensure data repeatability and reliability.

[0193] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. An ammonia synthesis column characterized in that, The application relates to a high-pressure reactor for preparing high-purity hydrogen, which comprises the following parts: a high-pressure outer cylinder (1) provided with a raw material gas inlet (2) and a circulating gas inlet (3) at the top and a reaction gas outlet (4) at the bottom; an inner cylinder (5) coaxially arranged in the high-pressure outer cylinder (1), and an annular gap (6) formed between the inner cylinder (5) and the high-pressure outer cylinder (1); a plurality of layers of catalyst beds (7) arranged along the axial direction of the inner cylinder (5) in sequence, and indirect heat exchange components (8) arranged between the layers of catalyst beds (7) for radial flow; an intelligent temperature control system (9) comprising distributed temperature sensors (10), flow regulating valves (11) and a central controller (12), wherein the temperature sensors (10) are embedded in each layer of catalyst beds (7), the flow regulating valves (11) are arranged on the raw material gas inlet (2), the circulating gas inlet (3) and the refrigerant pipelines (13) of the heat exchange components (8) respectively, and the central controller (12) dynamically adjusts the opening degrees of the regulating valves according to the feedback signals of the temperature sensors (10).

2. The ammonia converter according to claim 1, characterized in that The indirect heat exchange components (8) comprise: spiral coils (14) uniformly distributed between the catalyst beds (7), the spiral coils (14) internally flow through refrigerants and externally contact with reaction gas; baffle plates (15) fixed to the outer sides of the spiral coils (14) and guiding the reaction gas to flow along a spiral path; expansion joints (16) arranged at the inlets and outlets of the spiral coils (14) and compensating thermal stress.

3. The ammonia converter according to claim 1, characterized in that The catalyst beds (7) adopt a composite catalyst system, which comprises: a bottom layer (17) filled with a ruthenium-based catalyst, the ruthenium-based catalyst taking cerium dioxide-strontium oxide solid solution as a carrier and loading ruthenium (Ru) and bismuth (Bi) additives; an upper layer (18) filled with an iron-based catalyst, the iron-based catalyst taking alumina as a carrier and loading potassium (K) and calcium (Ca) additives; the volume ratio of the bottom layer (17) to the upper layer (18) is 1:2-1:

3.

4. The ammonia converter according to claim 1, characterized in that A plurality of guide vanes (19) are arranged in the annular gap (6), the guide vanes (19) are uniformly distributed along the circumferential direction, the guide vanes (19) guide the raw material gas and the circulating gas to form a cyclone in the annular gap (6) and strengthen the preheating effect.

5. The ammonia converter according to claim 1, characterized in that The reaction gas outlet (4) is connected with a waste heat boiler (20), the waste heat boiler (20) is communicated with the refrigerant pipelines (13) and forms a closed heat recovery system.

6. A method of synthesizing ammonia using the ammonia synthesis tower of claim 1, characterized by, The application further discloses a preparation method of high-purity hydrogen, which comprises the following steps: a preheating stage: raw material gas (H2:N2=3:1) enters the annular gap (6) through the raw material gas inlet (2), exchanges heat with high-temperature reaction gas led out by the inner cylinder (5) in countercurrent mode and is heated to 300-350 DEG C; a reaction stage: the preheated raw material gas is mixed with circulating gas, enters the inner cylinder (5) through the circulating gas inlet (3) and reacts through the plurality of layers of catalyst beds (7) in sequence, and the reaction temperature of each layer is controlled at 380-450 DEG C by adjusting the refrigerant flow through the intelligent temperature control system (9); heat recovery: high-temperature gas (400-420 DEG C) after reaction enters the waste heat boiler (20) through the reaction gas outlet (4), generates high-pressure steam (>=4 MPa) and returns the cooled reaction gas (200-220 DEG C) to the annular gap (6) to participate in raw material gas preheating. Circulation regulation: Unreacted raw material gas is separated by ammonia separator and returned to inner cylinder (5) through circulation gas inlet (3), and the central controller (12) adjusts circulation gas flow and heat exchange intensity between catalyst bed (7) according to real-time ammonia net value.

7. The method of claim 6, wherein, The control strategy of the intelligent temperature control system (9) comprises: When the temperature of a layer of catalyst bed (7) exceeds 450 DEG C, the central controller (12) automatically opens the refrigerant flow regulating valve (11) of the layer of heat exchange assembly (8) and reduces the raw material gas input of the upper layer of catalyst bed (7); When the system load is less than 30%, the central controller (12) starts the bypass mode, and part of the raw material gas is directly introduced into the refrigerant pipeline (13) of the heat exchange assembly (8) to maintain the activity temperature of the catalyst bed (7) through reaction heat.

8. The method of claim 6, wherein, The reduction method of the ruthenium-based catalyst comprises: Under the protection of nitrogen, the temperature is raised to 200 DEG C at 5 DEG C / min, 5% H2 / N2 mixed gas is introduced, and constant temperature reduction is carried out for 4 hours; The temperature is raised to 400 DEG C at 3 DEG C / min, pure hydrogen is introduced, and constant temperature reduction is carried out for 8 hours, and the content of chlorine element in the reduced catalyst is less than 100 ppm.

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