Synthetic ammonia control system and equipment thereof

Abstract

The embodiment of the invention provides a control system and equipment for ammonia synthesis. The system comprises a water electrolysis hydrogen production device, a nitrogen device, a gas mixing device, an ammonia synthesis device and a controller, the output end of the water electrolysis hydrogen production device is connected with the gas mixing device through a first pipeline, and the output end of the nitrogen device is connected with the gas mixing device through a second pipeline; the first pipeline comprises a first valve and a second valve, the adjusting precision of the first valve is smaller than that of the second valve, the second pipeline comprises a third valve and a fourth valve, and the adjusting precision of the third valve is smaller than that of the fourth valve; the controller is used for detecting the first hydrogen amount output by the water electrolysis hydrogen production device, determining the first load of the ammonia synthesis device based on the first hydrogen amount, and controlling the opening degrees of the first valve, the second valve, the third valve and the fourth valve based on the first load. The system is used for improving the production efficiency of synthetic ammonia.

Description

Technical Field

[0001] This application relates to the field of automation technology, and in particular to a control system and equipment for ammonia synthesis. Background Technology

[0002] With the rapid development of modern agriculture, the market demand for synthetic ammonia, a core raw material for nitrogen fertilizer production, has also experienced explosive growth, making it a key chemical product for ensuring agricultural production.

[0003] In existing technologies, a mixture of hydrogen and nitrogen in a predetermined ratio is introduced into an ammonia synthesis unit. With the help of a high-temperature and high-pressure environment and a special catalyst, the two gases undergo a chemical reaction to produce ammonia.

[0004] However, in actual production, the load of the ammonia synthesis unit is prone to rapid fluctuations, leading to an imbalance in the feed gas ratio and consequently resulting in low production efficiency of ammonia synthesis. Summary of the Invention

[0005] This application provides a control system and equipment for ammonia synthesis to improve the production efficiency of ammonia synthesis.

[0006] In a first aspect, embodiments of this application provide a control system for ammonia synthesis, including a water electrolysis hydrogen production device, a nitrogen device, a gas mixing device, an ammonia synthesis device, and a controller, wherein...

[0007] The output of the water electrolysis hydrogen production unit is connected to the gas mixing unit through the first pipeline, the output of the nitrogen unit is connected to the gas mixing unit through the second pipeline, and the output of the gas mixing unit is connected to the ammonia synthesis unit.

[0008] The first pipeline includes a first valve and a second valve, the adjustment accuracy of the first valve is less than that of the second valve; the second pipeline includes a third valve and a fourth valve, the adjustment accuracy of the third valve is less than that of the fourth valve.

[0009] The gas mixing device is used to mix the hydrogen output from the water electrolysis hydrogen production device with the nitrogen output from the nitrogen device to a preset ratio, and then transmit the mixed gas to the ammonia synthesis device.

[0010] Ammonia synthesis units are used to convert mixed gases into ammonia;

[0011] The controller is used to detect the first amount of hydrogen output from the water electrolysis hydrogen production unit, and based on the first amount of hydrogen, to determine the first load of the ammonia synthesis unit. Based on the first load, the controller controls the opening of the first valve, the second valve, the third valve, and the fourth valve so that the amount of hydrogen and nitrogen entering the gas mixing unit matches the first load.

[0012] In one possible implementation, the controller is specifically used for:

[0013] Determine the amount of second hydrogen required for the maximum ammonia production of the ammonia synthesis unit;

[0014] The ratio of the first hydrogen quantity to the second hydrogen quantity is determined as the first load.

[0015] In one possible implementation, the controller is specifically used for:

[0016] Determine the target hydrogen and nitrogen quantities required for the first load;

[0017] When the first load is less than or equal to the first threshold, the opening of the second valve is controlled to match the amount of hydrogen entering the gas mixing device with the target amount of hydrogen, and the opening of the fourth valve is controlled to match the amount of nitrogen entering the gas mixing device with the target amount of nitrogen.

[0018] When the first load is greater than the first threshold and less than the second threshold, the opening of the first valve and the second valve are controlled to match the amount of hydrogen entering the gas mixing device with the target amount of hydrogen, and the opening of the third valve and the fourth valve are controlled to match the amount of nitrogen entering the gas mixing device with the target amount of nitrogen.

[0019] When the first load is greater than or equal to the second threshold, the opening of the first valve is controlled to match the amount of hydrogen entering the gas mixing device with the target amount of hydrogen, and the opening of the third valve is controlled to match the amount of nitrogen entering the gas mixing device with the target amount of nitrogen.

[0020] In one possible implementation, when the first load is greater than a first threshold and less than a second threshold, the controller is specifically configured to:

[0021] The opening of the first valve is controlled, and when the difference between the amount of hydrogen entering the gas mixing device and the target amount of hydrogen is less than or equal to the third threshold, the opening of the first valve is maintained, and the opening of the second valve is controlled so that the amount of hydrogen entering the gas mixing device matches the target amount of hydrogen.

[0022] The opening of the third valve is controlled, and when the difference between the amount of nitrogen entering the gas mixing device and the target amount of nitrogen is less than or equal to the fourth threshold, the opening of the third valve is maintained, and the opening of the fourth valve is controlled so that the amount of nitrogen entering the gas mixing device matches the target amount of nitrogen.

[0023] In one possible implementation, the ammonia synthesis unit includes a compressor and a synthesis tower, with the input end of the compressor connected to the output end of a gas mixing device and the output end of the compressor connected to the input end of the synthesis tower.

[0024] The compressor is used to pressurize the mixed gas;

[0025] The synthesis tower is used to convert a mixed gas into ammonia;

[0026] The controller is also used to reduce the proportion of circulating gas in the synthesis tower and the pressure of the synthesis tower when the first load is less than or equal to the first threshold; and to increase the pressure of the synthesis tower when the first load is greater than or equal to the second threshold, wherein the circulating gas is an unreacted mixture of gases in the synthesis tower.

[0027] In one possible implementation, the controller is also used for:

[0028] Detect the hydrogen-nitrogen ratio at the compressor input;

[0029] When the deviation of the hydrogen-nitrogen ratio from the preset ratio is greater than or equal to the fifth threshold and less than the sixth threshold, an alarm message for hydrogen-nitrogen ratio mismatch at the compressor input is generated.

[0030] When the deviation of the hydrogen-nitrogen ratio from the preset ratio is greater than or equal to the sixth threshold, the shut-off valve at the compressor input is closed, the surge valve of the compressor is opened, and the vent valve at the compressor input is opened so that the mixed gas with the imbalanced hydrogen-nitrogen ratio can be vented through the vent valve.

[0031] In one possible implementation, the ammonia synthesis control system further includes an ammonia separation device, the input of which is connected to the output of the synthesis tower;

[0032] The ammonia separation unit is used to separate liquid ammonia and circulating gas.

[0033] In one possible implementation, the output of the circulating gas from the ammonia separator is also connected to the input of the compressor.

[0034] The ammonia separation unit is also used to transfer unreacted circulating gas to the compressor.

[0035] In one possible implementation, the first pipe further includes a first flow meter and a second flow meter, and the second pipe further includes a third flow meter and a fourth flow meter;

[0036] The first flow meter is used to detect the flow rate of the first valve;

[0037] The second flow meter is used to detect the flow rate of the second valve;

[0038] The third flow meter is used to detect the flow rate of the third valve;

[0039] The fourth flow meter is used to detect the flow rate of the fourth valve;

[0040] The controller is also used to correct the opening control of the first valve based on the flow rate detected by the first flow meter, correct the opening control of the second valve based on the flow rate detected by the second flow meter, correct the opening control of the third valve based on the flow rate detected by the third flow meter, and correct the opening control of the fourth valve based on the flow rate detected by the fourth flow meter.

[0041] Secondly, embodiments of this application provide a control device for synthetic ammonia, including the synthetic ammonia control system of any one of the first aspects.

[0042] The control system and equipment for ammonia synthesis provided in this application embodiment employ a dual-precision valve combination design with coarse and fine adjustments. The first and third valves can quickly respond to large flow demands to shorten system response time, while the second and fourth valves can precisely correct flow deviations, ensuring that hydrogen and nitrogen gases are mixed strictly in the optimal ratio for ammonia synthesis, reducing side reactions and raw material waste. Simultaneously, the controller uses the actual hydrogen output of the water electrolysis hydrogen production unit as the core basis to dynamically calculate the real-time load of the ammonia synthesis unit and precisely adjust the hydrogen and nitrogen gas supply according to load requirements. This avoids energy waste due to excess raw materials or idle unit capacity due to insufficient raw materials, ensuring that the ammonia synthesis unit always operates within the optimal load range, significantly improving the production efficiency of ammonia synthesis. Attached Figure Description

[0043] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0044] Figure 1 A schematic diagram of the control system for ammonia synthesis provided in this application embodiment. Figure 1 ;

[0045] Figure 2 A schematic diagram of the control system for ammonia synthesis provided in this application embodiment. Figure 2 ;

[0046] Figure 3 A schematic diagram of the control system for ammonia synthesis provided in this application embodiment. Figure 3 .

[0047] Figure label:

[0048] 10-Water electrolysis hydrogen production unit;

[0049] 20-Nitrogen gas device;

[0050] 30 - Gas mixing device;

[0051] 40-Ammonia Synthesis Unit;

[0052] 50-Controller;

[0053] 60 - First Pipeline;

[0054] 601 - First Valve;

[0055] 602 - Second valve;

[0056] 603 - First Flow Meter;

[0057] 604 - Second Flow Meter;

[0058] 70 - Second Pipeline;

[0059] 701 - Third Valve;

[0060] 702 - Fourth Valve;

[0061] 703 - Third Flow Meter;

[0062] 704 - Fourth Flow Meter;

[0063] 80-Ammonia Separation Unit.

[0064] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0065] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0066] To address the technical issues of rapid load fluctuations in the aforementioned ammonia synthesis unit leading to imbalances in the feedstock gas ratio and low production efficiency, the following technical concept is proposed: The actual hydrogen output of the water electrolysis hydrogen production unit 10 is quantified in real-time to determine the load. A dual-valve combination of "coarse adjustment + fine adjustment" dynamically matches the hydrogen-nitrogen feedstock ratio according to the load range. Combined with designs such as circulating gas recovery, dynamic optimization of unit parameters, and flow closed-loop correction, precise feedstock supply under load fluctuations is achieved. Simultaneously, a tiered alarm and emergency protection mechanism ensures system stability, ultimately significantly improving ammonia synthesis production efficiency, feedstock utilization, and operational safety, systematically resolving the core technical pain points caused by load fluctuations.

[0067] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0068] Figure 1 A schematic diagram of the control system for ammonia synthesis provided in this application embodiment. Figure 1 .like Figure 1 As shown, the system includes: a water electrolysis hydrogen production unit 10, a nitrogen unit 20, a gas mixing unit 30, an ammonia synthesis unit 40, and a controller 50, wherein...

[0069] The output end of the water electrolysis hydrogen production device 10 is connected to the gas mixing device 30 through the first pipe 60, the output end of the nitrogen device 20 is connected to the gas mixing device 30 through the second pipe 70, and the output end of the gas mixing device 30 is connected to the ammonia synthesis device 40.

[0070] The first pipeline 60 includes a first valve 601 and a second valve 602. The adjustment accuracy of the first valve 601 is less than that of the second valve 602. The second pipeline 70 includes a third valve 701 and a fourth valve 702. The adjustment accuracy of the third valve 701 is less than that of the fourth valve 702.

[0071] The gas mixing device 30 is used to mix the hydrogen output from the water electrolysis hydrogen production device 10 with the nitrogen output from the nitrogen device 20 to a preset ratio, and to transmit the mixed gas to the ammonia synthesis device 40.

[0072] Ammonia synthesis unit 40 is used to convert mixed gas into ammonia;

[0073] The controller 50 is used to detect the first amount of hydrogen output from the water electrolysis hydrogen production device 10, and based on the first amount of hydrogen, to determine the first load of the ammonia synthesis device 40. Based on the first load, the controller controls the opening of the first valve 601, the second valve 602, the third valve 701 and the fourth valve 702 so that the amount of hydrogen and nitrogen entering the gas mixing device 30 matches the first load.

[0074] Among them, the water electrolysis hydrogen production unit 10 is a specialized device for producing high-purity hydrogen through the water electrolysis reaction, and it is the core source of hydrogen in the ammonia synthesis process. The purity and flow rate stability of its output hydrogen directly affect the efficiency of subsequent ammonia synthesis, and it is usually equipped with flow and pressure detection modules to achieve process monitoring.

[0075] Nitrogen device 20 is a device used to provide nitrogen required for ammonia synthesis. Common forms include air separation devices (extracting nitrogen from the air through cryogenic separation or pressure swing adsorption) or liquid nitrogen vaporization systems. It is necessary to ensure that the purity of the output nitrogen is ≥99.9% to avoid impurities affecting the catalyst activity.

[0076] The gas mixing device 30 is a device with the functions of uniform gas mixing and proportion adjustment. It is usually equipped with a static mixer or stirring mechanism inside, which can accurately mix hydrogen and nitrogen according to the theoretical ratio required for ammonia synthesis (H2:N2=3:1), while eliminating gas turbulence and ensuring that the mixed gas composition is uniform and stable.

[0077] The ammonia synthesis unit 40 is the core reaction unit of the ammonia synthesis process, mainly composed of a synthesis tower, heat exchanger, separator, etc. Under high temperature (300-500℃), high pressure (10-30MPa) and iron-based catalyst, the hydrogen-nitrogen mixture is converted into ammonia, and the unreacted gas is recycled.

[0078] The controller 50 is typically a programmable logic controller 50 or the core control module of a distributed control system. It has functions such as data acquisition, logic operation, and instruction output. It can acquire equipment operating parameters in real time through sensors and control valve opening and other actions based on preset algorithms.

[0079] The first, second, third, and fourth valves are all control valves used to regulate the gas flow rate in the pipeline. Among them, "first valve 601" and "third valve 701" are coarse adjustment valves (such as gate valves and butterfly valves), with low adjustment accuracy (typically control error ±5%), suitable for rapid adjustment over a large flow range; "second valve 602" and "fourth valve 702" are fine adjustment valves (such as regulating valves and needle valves), with high adjustment accuracy (control error ≤ ±1%), used to achieve precise flow control based on coarse adjustment.

[0080] The first load is the real-time production capacity status of the ammonia synthesis unit 40, reflecting the maximum load of the mixed gas it can currently handle. It is related to parameters such as catalyst activity, reaction temperature and pressure, and circulating gas flow rate in the synthesis tower, and is the core basis for determining the supply of hydrogen and nitrogen gas.

[0081] Specifically, after the system starts up, the water electrolysis hydrogen production unit 10 and the nitrogen production unit 20 begin to work, producing hydrogen and nitrogen respectively. At this time, the controller 50 controls all valves to be in a small opening initial state by default, ensuring that the gas enters the first and second pipelines at a low flow rate and avoiding instantaneous high pressure impact on the equipment.

[0082] The controller 50 collects and records the initial hydrogen quantity in real time, which is the actual hydrogen flow rate currently output by the water electrolysis hydrogen production unit 10. This parameter is the "initial basis" for system adjustment, because hydrogen is a key raw material for the ammonia synthesis reaction, and its supply capacity directly determines the production ceiling of the entire system.

[0083] The controller 50 calculates the first load of the ammonia synthesis unit 40 based on a preset hydrogen quantity-load correspondence model. This model is established based on the stoichiometric relationship of the ammonia synthesis reaction (3 volumes of hydrogen correspond to 2 volumes of ammonia) and actual operating data of the unit. For example, if the first hydrogen quantity is 300 Nm³ / h (standard cubic meters per hour), combined with correction parameters such as catalyst activity coefficient and reaction conversion rate, the maximum corresponding load that the synthesis unit can currently handle can be calculated (e.g., the capacity to convert and generate 200 Nm³ of ammonia per hour). If the first hydrogen quantity fluctuates, the first load will also be dynamically adjusted accordingly to ensure that the load matches the feedstock supply capacity.

[0084] Based on the first load, controller 50 calculates the "target hydrogen quantity" and "target nitrogen quantity" (matched in a 3:1 ratio) entering gas mixing device 30, and then controls the opening of each valve in two steps:

[0085] 1. Coarse Adjustment Stage: Prioritize adjusting the first valve 601 (hydrogen coarse adjustment valve) and the third valve 701 (nitrogen coarse adjustment valve). For example, if the target hydrogen flow rate is 300 Nm³ / h and the current hydrogen flow rate is 200 Nm³ / h, the controller 50 will quickly increase the opening of the first valve 601, causing the hydrogen flow rate to rapidly approach the target value; simultaneously, it will proportionally increase the opening of the third valve 701, causing the nitrogen flow rate to approach 100 Nm³ / h (3:1 ratio). This stage utilizes the large adjustment range of the coarse adjustment valves to shorten the time it takes for the flow rate to reach the target range.

[0086] 2. Fine-tuning Phase: When the hydrogen flow rate in the first pipeline 60 approaches 300 Nm³ / h and the nitrogen flow rate in the second pipeline 70 approaches 100 Nm³ / h, the controller 50 switches to fine-tuning mode. By adjusting the slight openings of the second valve 602 and the fourth valve 702, the flow rates are precisely corrected. For example, if the hydrogen flow rate is stable at 295 Nm³ / h, the controller 50 fine-tunes the opening of the second valve 602 by 0.5% to bring the flow rate up to 300 Nm³ / h; if the nitrogen flow rate is 98 Nm³ / h, the controller fine-tunes the opening of the fourth valve 702 by 0.2% to ensure the hydrogen-nitrogen ratio is strictly maintained at 3:1.

[0087] Possibly, precisely regulated hydrogen and nitrogen enter the gas mixing device 30, where they are uniformly mixed before being input into the ammonia synthesis unit 40 at a stable flow rate. Simultaneously, the controller 50 monitors parameters such as the outlet ammonia yield, reaction temperature, and pressure of the ammonia synthesis unit 40 in real time. If the ammonia yield is found to be lower than expected, it will trace back to check for fluctuations in the initial hydrogen flow, recalculate the initial load, and adjust the valve opening, forming a closed-loop system of "acquisition-calculation-control-feedback" to ensure stable production.

[0088] The ammonia synthesis control system provided in this application embodiment employs a dual-precision valve combination design with coarse and fine adjustments. The first and third valves can quickly respond to large flow demands to shorten the system response time, while the second and fourth valves can precisely correct flow deviations, ensuring that hydrogen and nitrogen gases are mixed strictly in the optimal ratio for the ammonia synthesis reaction, reducing side reactions and raw material waste. Simultaneously, the controller 50 uses the actual hydrogen output of the water electrolysis hydrogen production unit 10 as the core basis to dynamically calculate the real-time load of the ammonia synthesis unit 40 and precisely adjusts the hydrogen and nitrogen gas supply according to load requirements. This avoids energy waste due to excess raw materials or idle capacity of the unit due to insufficient raw materials, ensuring that the ammonia synthesis unit 40 always operates within the optimal load range, significantly improving the production efficiency of ammonia synthesis.

[0089] Figure 2 A schematic diagram of the control system for ammonia synthesis provided in this application embodiment. Figure 2 .

[0090] In one possible implementation, the controller 50 is specifically configured to: determine the second amount of hydrogen required for the maximum ammonia production corresponding to the ammonia synthesis unit 40; and determine the ratio of the first amount of hydrogen to the second amount of hydrogen as the first load.

[0091] The second hydrogen quantity is the theoretical amount of hydrogen required for the ammonia synthesis unit 40 to achieve maximum ammonia production under design conditions (such as full-load operation) (determined by parameters such as unit capacity and reaction efficiency).

[0092] Specifically, the controller 50, based on the design parameters of the ammonia synthesis unit 40 (such as maximum ammonia production, hydrogen-nitrogen reaction ratio, conversion rate, etc.), pre-calculates or calls the preset second hydrogen quantity corresponding to the maximum ammonia production (e.g., a maximum ammonia production of 500 kg / h corresponds to a second hydrogen quantity of 500 Nm³ / h). The controller 50 monitors the first hydrogen quantity output by the water electrolysis hydrogen production unit 10 in real time (e.g., 400 Nm³ / h) and calculates the load value (e.g., 400 ÷ 500 × 100% = 80%) using the formula "first load = (first hydrogen quantity ÷ second hydrogen quantity) × 100%".

[0093] By defining the first load as the ratio of the first hydrogen quantity to the second hydrogen quantity required for maximum ammonia production, the load quantification of the ammonia synthesis unit 40 becomes more intuitive and accurate. This solves the complexity of load assessment relying on multi-parameter calculations, ensuring that subsequent regulation can strictly match the actual capacity of the unit, avoiding raw material waste or capacity idleness due to load judgment deviations, and providing a clear quantitative basis for efficient production.

[0094] In one possible implementation, the controller 50 is specifically configured to: determine the target amount of hydrogen and the target amount of nitrogen required for the first load; when the first load is less than or equal to a first threshold, control the opening of the second valve 602 to match the amount of hydrogen entering the gas mixing device 30 with the target amount of hydrogen, and control the opening of the fourth valve 702 to match the amount of nitrogen entering the gas mixing device 30 with the target amount of nitrogen; and when the first load is greater than the first threshold and less than the second threshold, control the opening of the first valve 601 and the second valve 602. The opening degree of the first valve 601 is controlled to match the amount of hydrogen entering the gas mixing device 30 with the target amount of hydrogen, and the opening degree of the third valve 701 and the fourth valve 702 is controlled to match the amount of nitrogen entering the gas mixing device 30 with the target amount of nitrogen; when the first load is greater than or equal to the second threshold, the opening degree of the first valve 601 is controlled to match the amount of hydrogen entering the gas mixing device 30 with the target amount of hydrogen, and the opening degree of the third valve 701 is controlled to match the amount of nitrogen entering the gas mixing device 30 with the target amount of nitrogen.

[0095] The target hydrogen / nitrogen quantity is the theoretical demand for hydrogen and nitrogen entering the gas mixing device 30, calculated based on the first load (in a 3:1 ratio). For example, 80% load corresponds to a target hydrogen quantity of 480 Nm³ / h and a target nitrogen quantity of 160 Nm³ / h.

[0096] The first threshold and the second threshold are critical values ​​for dividing the load range (e.g., the first threshold is 30% and the second threshold is 70%), which are used to determine the valve control strategy (fine-tuning / coarse-tuning + fine-tuning / coarse-tuning).

[0097] Specifically, the controller 50 determines the target hydrogen and nitrogen quantities based on the first load and a 3:1 ratio.

[0098] Low load (≤ first threshold, e.g., ≤30%): Adjust only the second valve 602 (hydrogen fine adjustment) and the fourth valve 702 (nitrogen fine adjustment). Due to the small flow requirement, the fine adjustment valves are sufficient to meet the accuracy requirements, avoiding excessive adjustment errors from the coarse adjustment valves.

[0099] Medium load (> first threshold and < second threshold, such as 30%-70%): Simultaneously adjust the first valve 601 (hydrogen coarse adjustment), the second valve 602 (hydrogen fine adjustment), the third valve 701 (nitrogen coarse adjustment), and the fourth valve 702 (nitrogen fine adjustment). Coarse adjustment quickly approaches the target, while fine adjustment corrects deviations, balancing efficiency and accuracy.

[0100] High load (≥ second threshold, e.g., ≥70%): Adjust only the first valve 601 (hydrogen coarse adjustment) and the third valve 701 (nitrogen coarse adjustment). Due to the large flow demand, the adjustment range of the coarse adjustment valve is sufficient to cover the demand and the response is faster, avoiding insufficient stroke of the fine adjustment valve.

[0101] The valve control strategy (fine adjustment / coarse adjustment + fine adjustment / coarse adjustment) can be flexibly selected according to the load range (low, medium, high), which not only ensures the flow regulation accuracy at low loads, but also improves the response speed at medium and high loads, realizing efficient matching of hydrogen and nitrogen gas under different loads and further optimizing production efficiency.

[0102] In one possible implementation, when the first load is greater than a first threshold and less than a second threshold; the controller 50 is specifically configured to:

[0103] The opening of the first valve 601 is controlled, and when the difference between the amount of hydrogen entering the gas mixing device 30 and the target amount of hydrogen is less than or equal to a third threshold, the opening of the first valve 601 is maintained, and the opening of the second valve 602 is controlled to match the amount of hydrogen entering the gas mixing device 30 with the target amount of hydrogen; the opening of the third valve 701 is controlled, and when the difference between the amount of nitrogen entering the gas mixing device 30 and the target amount of nitrogen is less than or equal to a fourth threshold, the opening of the third valve 701 is maintained, and the opening of the fourth valve 702 is controlled to match the amount of nitrogen entering the gas mixing device 30 with the target amount of nitrogen.

[0104] Among them, the third threshold and the fourth threshold are the allowable deviation values ​​between the flow rate and the target amount during the coarse adjustment stage (such as ±5 Nm³ / h), which are used to trigger the condition for switching from coarse adjustment to fine adjustment.

[0105] Specifically, when the load is moderate (e.g., the initial load is between 30% and 70%), the controller 50 adopts a "coarse adjustment priority, fine adjustment supplement" strategy:

[0106] Hydrogen regulation: First, control the opening of the first valve 601 (coarse adjustment) to increase / decrease, and monitor the amount of hydrogen entering the mixing device in real time; when the difference between the amount of hydrogen and the target amount of hydrogen is ≤ the third threshold (e.g., ±5 Nm³ / h), lock the opening of the first valve 601 and switch to the second valve 602 (fine adjustment) for fine adjustment until it is completely matched to the target value.

[0107] Nitrogen regulation: Synchronously control the third valve 701 (coarse adjustment). When the difference between the nitrogen quantity and the target nitrogen quantity is ≤ the fourth threshold (e.g., ±2 Nm³ / h), lock the opening of the third valve 701 and switch to the fourth valve 702 (fine adjustment) for fine adjustment to ensure accurate ratio.

[0108] In the medium load range, a step-by-step control logic of "coarse adjustment approximation + fine adjustment locking" is adopted. By setting the third and fourth thresholds to trigger switching, the coarse adjustment valve is used to quickly reduce the flow deviation, while the fine adjustment valve is used to eliminate minor errors. This balances the adjustment efficiency and accuracy, reduces wear caused by frequent valve operation, and ensures the stability of the hydrogen-nitrogen ratio in the core range of medium load, thereby improving the reaction conversion rate.

[0109] In one possible implementation, such as Figure 2 As shown: Ammonia synthesis unit 40 includes a compressor and a synthesis tower. The input end of the compressor is connected to the output end of the gas mixing unit 30, and the output end of the compressor is connected to the input end of the synthesis tower.

[0110] The compressor is used to pressurize the mixed gas;

[0111] The synthesis tower is used to convert a mixed gas into ammonia;

[0112] The controller 50 is also used to reduce the proportion of circulating gas in the synthesis tower and the pressure of the synthesis tower when the first load is less than or equal to the first threshold; and to increase the pressure of the synthesis tower when the first load is greater than or equal to the second threshold, wherein the circulating gas is an unreacted mixture of gases in the synthesis tower.

[0113] Specifically, while adjusting the valves, controller 50 simultaneously optimizes the operating parameters of ammonia synthesis unit 40:

[0114] Low load (first load ≤ first threshold, such as ≤30%): reduce the proportion of circulating gas (reduce the amount of unreacted gas circulating and avoid energy waste); reduce the pressure of the synthesis tower (adapt to low load reaction conditions and reduce compressor energy consumption).

[0115] High load (first load ≥ second threshold, such as ≥70%): Increase the synthesis tower pressure (promote the forward reaction and improve the conversion rate); the circulating gas volume ratio is operated at the default optimal value (to ensure that unreacted gases are fully recovered).

[0116] For example, when the first load is a low load of 20%: the synthesis tower pressure drops from 20MPa to 15MPa, and the recirculated gas ratio drops from 80% to 50%, reducing compressor power consumption. When the first load is a high load of 90%: the synthesis tower pressure is increased to 25MPa, the recirculated gas ratio remains at 80%, unreacted gas is fully circulated, and the reaction conversion rate is improved.

[0117] By dynamically adjusting the pressure and circulating gas ratio of the synthesis tower under different loads, the operating parameters of the unit are deeply adapted to the load requirements: reducing pressure and circulating ratio at low loads reduces energy consumption, while increasing pressure at high loads promotes the reaction, thus achieving a balance between energy consumption and reaction efficiency.

[0118] In one possible implementation, the controller 50 is further configured to: detect the hydrogen-nitrogen ratio at the compressor input; generate an alarm message indicating a hydrogen-nitrogen ratio imbalance at the compressor input when the deviation of the hydrogen-nitrogen ratio from the preset ratio is greater than or equal to a fifth threshold and less than a sixth threshold; and close the shut-off valve at the compressor input, open the compressor surge valve, and open the vent valve at the compressor input when the deviation of the hydrogen-nitrogen ratio from the preset ratio is greater than or equal to the sixth threshold, so that the mixed gas with an imbalanced hydrogen-nitrogen ratio is vented through the vent valve.

[0119] Among them, the shut-off valve / surge valve / vent valve are safety control valves, used to shut off the gas source, prevent compressor surge, and discharge substandard gas, respectively.

[0120] Specifically, the controller 50 monitors the hydrogen-nitrogen mixing ratio at the compressor input in real time. If the deviation is ≥ the fifth threshold and < the sixth threshold (e.g., 0.3 ≤ deviation < 0.8): an alarm message (e.g., audible and visual alarm) is generated to prompt operator intervention. If the deviation is ≥ the sixth threshold (e.g., ≥ 0.8): emergency protection is triggered, closing the compressor input shut-off valve (stopping gas intake), opening the surge valve (protecting the compressor), and opening the vent valve (releasing substandard gas) to prevent substandard gas from entering the synthesis tower and causing catalyst poisoning.

[0121] By classifying the deviation in the hydrogen-nitrogen ratio, timely early warning and intervention can be provided when the imbalance is slight to prevent the deviation from expanding. In the event of a severe imbalance, the compressor and synthesis tower catalyst can be protected by cutting off the gas source and venting substandard gases, thereby reducing the risk of equipment damage and production interruption and ensuring the safe and stable operation of the system.

[0122] In one possible implementation, such as Figure 2 As shown, the ammonia synthesis control system also includes an ammonia separation device 80, the input end of which is connected to the output end of the synthesis tower; the ammonia separation device 80 is used to separate liquid ammonia and circulating gas.

[0123] Specifically, the ammonia generated in the synthesis tower and the unreacted mixed gas enter the ammonia separation unit 80. The ammonia is liquefied by cooling (e.g., to below -33°C), and the liquid ammonia is discharged from the bottom (as a product), while the unreacted circulating gas (hydrogen + nitrogen) is discharged from the top.

[0124] The ammonia separation unit 80 effectively separates liquid ammonia from unreacted gases, ensuring the purity of the ammonia product and laying the foundation for the recovery and utilization of unreacted hydrogen and nitrogen gases. This avoids the waste of direct emission of raw materials, improves the overall utilization rate of raw materials, and reduces the raw material consumption per unit of ammonia product.

[0125] In one possible implementation, the output of the ammonia separation unit 80 is also connected to the input of the compressor; the ammonia separation unit 80 is also used to transfer unreacted circulating gas to the compressor.

[0126] Specifically, the recycle gas (with a hydrogen-to-nitrogen ratio still close to 3:1) separated by the ammonia separator 80 is discharged from the output end. The recycle gas is transported through a pipeline to the compressor input end, where it is mixed with the new mixed gas output from the gas mixing unit 30. The mixed gas is then pressurized by the compressor and re-enters the synthesis tower, where unreacted hydrogen and nitrogen continue to participate in ammonia synthesis, improving the raw material utilization rate.

[0127] In one possible implementation, the first pipe 60 further includes a first flow meter 603 and a second flow meter 604, and the second pipe 70 further includes a third flow meter 703 and a fourth flow meter 704.

[0128] The first flow meter 603 is used to detect the flow rate of the first valve 601;

[0129] The second flow meter 604 is used to detect the flow rate of the second valve 602;

[0130] The third flow meter 703 is used to detect the flow rate of the third valve 701;

[0131] The fourth flow meter 704 is used to detect the flow rate of the fourth valve 702;

[0132] The controller 50 is also used to correct the opening control of the first valve 601 based on the flow rate detected by the first flow meter 603, correct the opening control of the second valve 602 based on the flow rate detected by the second flow meter 604, correct the opening control of the third valve 701 based on the flow rate detected by the third flow meter 703, and correct the opening control of the fourth valve 702 based on the flow rate detected by the fourth flow meter 704.

[0133] Among them, the first, second, third, and fourth flow meters are flow detection devices (such as vortex flow meters) installed downstream of the first, second, third, and fourth valves, respectively, to measure the actual output flow of the corresponding valves in real time.

[0134] Specifically, each flow meter detects the output flow of its corresponding valve (e.g., the first flow meter 603 measures the hydrogen flow of the first valve 601) and transmits the data to the controller 50. The controller 50 compares the measured flow with the target flow and calculates the deviation (e.g., target 200 Nm³ / h, measured 190 Nm³ / h, deviation -10 Nm³ / h). Based on the deviation, the valve opening is corrected (e.g., the original command for the first valve 601 is 40%, but due to the low flow, it is corrected to 42%) until the measured flow matches the target.

[0135] By using flow meters to monitor the flow rate of each valve in real time and correct the opening, a closed-loop control of "command-detection-correction" is formed. This effectively offsets the flow deviation caused by factors such as valve wear and changes in pipeline resistance, ensuring that the amount of hydrogen and nitrogen entering the mixing unit always accurately matches the target value. This avoids the imbalance of reaction ratio caused by flow errors and further improves production stability and efficiency.

[0136] In one possible implementation, Figure 3 A schematic diagram of the control system for ammonia synthesis provided in this application embodiment. Figure 3 .like Figure 3 As shown, Figure 3 The control system for synthetic ammonia provided in the paper has a first valve 601 and a second valve 602 connected in parallel, as well as a third valve 701 and a fourth valve 702 connected in parallel.

[0137] It should be noted that, Figure 3 The control system for ammonia synthesis provided can implement the above embodiments and achieve the corresponding beneficial effects, which will not be elaborated further here.

[0138] This application provides a control device for ammonia synthesis, including the ammonia synthesis control system provided in any of the above embodiments.

[0139] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A control system for ammonia synthesis, characterized in that, It includes a water electrolysis hydrogen production unit, a nitrogen unit, a gas mixing unit, an ammonia synthesis unit, and a controller, among which, The output of the water electrolysis hydrogen production device is connected to the gas mixing device through a first pipe, the output of the nitrogen device is connected to the gas mixing device through a second pipe, and the output of the gas mixing device is connected to the ammonia synthesis device. The first pipeline includes a first valve and a second valve, the adjustment accuracy of the first valve is less than that of the second valve, and the second pipeline includes a third valve and a fourth valve, the adjustment accuracy of the third valve is less than that of the fourth valve. The gas mixing device is used to mix the hydrogen output from the water electrolysis hydrogen production device with the nitrogen output from the nitrogen device to a preset ratio, and to transmit the mixed gas to the ammonia synthesis device; The ammonia synthesis device is used to convert the mixed gas into ammonia; The controller is used to detect the first amount of hydrogen output from the water electrolysis hydrogen production device, and based on the first amount of hydrogen, determine the first load of the ammonia synthesis device, and based on the first load, control the opening of the first valve, the second valve, the third valve and the fourth valve so that the amount of hydrogen and nitrogen entering the gas mixing device matches the first load.

2. The control system for ammonia synthesis according to claim 1, characterized in that, The controller is specifically used for: Determine the second hydrogen quantity required for the maximum ammonia production of the ammonia synthesis unit; The ratio of the first hydrogen quantity to the second hydrogen quantity is determined as the first load.

3. The control system for ammonia synthesis according to claim 2, characterized in that, The controller is specifically used for: Determine the target hydrogen and nitrogen quantities required for the first load; When the first load is less than or equal to the first threshold, the opening of the second valve is controlled to match the amount of hydrogen entering the gas mixing device with the target amount of hydrogen, and the opening of the fourth valve is controlled to match the amount of nitrogen entering the gas mixing device with the target amount of nitrogen. When the first load is greater than the first threshold and less than the second threshold, the opening of the first valve and the second valve is controlled to match the amount of hydrogen entering the gas mixing device with the target amount of hydrogen, and the opening of the third valve and the fourth valve is controlled to match the amount of nitrogen entering the gas mixing device with the target amount of nitrogen. When the first load is greater than or equal to the second threshold, the opening of the first valve is controlled to match the amount of hydrogen entering the gas mixing device with the target amount of hydrogen, and the opening of the third valve is controlled to match the amount of nitrogen entering the gas mixing device with the target amount of nitrogen.

4. The control system for ammonia synthesis according to claim 3, characterized in that, When the first load is greater than a first threshold and less than a second threshold; the controller is specifically used to: The opening degree of the first valve is controlled, and when the difference between the amount of hydrogen entering the gas mixing device and the target amount of hydrogen is less than or equal to a third threshold, the opening degree of the first valve is maintained, and the opening degree of the second valve is controlled so that the amount of hydrogen entering the gas mixing device matches the target amount of hydrogen. The opening of the third valve is controlled, and when the difference between the amount of nitrogen entering the gas mixing device and the target amount of nitrogen is less than or equal to a fourth threshold, the opening of the third valve is maintained, and the opening of the fourth valve is controlled so that the amount of nitrogen entering the gas mixing device matches the target amount of nitrogen.

5. The control system for ammonia synthesis according to any one of claims 1-4, characterized in that, The ammonia synthesis unit includes a compressor and a synthesis tower. The input end of the compressor is connected to the output end of the gas mixing unit, and the output end of the compressor is connected to the input end of the synthesis tower. The compressor is used to pressurize the mixed gas; The synthesis tower is used to convert the mixed gas into ammonia; The controller is also configured to reduce the proportion of circulating gas in the synthesis tower and the pressure of the synthesis tower when the first load is less than or equal to a first threshold; and to increase the pressure of the synthesis tower when the first load is greater than or equal to a second threshold, wherein the circulating gas is an unreacted mixed gas in the synthesis tower.

6. The control system for ammonia synthesis according to claim 5, characterized in that, The controller is also used for: The hydrogen-nitrogen ratio at the compressor input terminal is detected; When the deviation of the hydrogen-nitrogen ratio from the preset ratio is greater than or equal to the fifth threshold and less than the sixth threshold, an alarm message indicating a hydrogen-nitrogen ratio mismatch at the compressor input is generated. When the deviation of the hydrogen-nitrogen ratio from the preset ratio is greater than or equal to the sixth threshold, the shut-off valve at the compressor input is closed, the surge valve at the compressor is opened, and the vent valve at the compressor input is opened so that the mixed gas with the imbalanced hydrogen-nitrogen ratio is vented through the vent valve.

7. The control system for ammonia synthesis according to claim 5, characterized in that, The ammonia synthesis control system also includes an ammonia separation device, the input end of which is connected to the output end of the synthesis tower. The ammonia separation device is used to separate liquid ammonia and circulating gas.

8. The control system for ammonia synthesis according to claim 7, characterized in that, The output end of the circulating gas of the ammonia separation device is also connected to the input end of the compressor; The ammonia separation unit is also used to transfer unreacted circulating gas to the compressor.

9. The control system for ammonia synthesis according to any one of claims 1-4, characterized in that, The first pipe also includes a first flow meter and a second flow meter, and the second pipe also includes a third flow meter and a fourth flow meter; The first flow meter is used to detect the flow rate of the first valve; The second flow meter is used to detect the flow rate of the second valve; The third flow meter is used to detect the flow rate of the third valve; The fourth flow meter is used to detect the flow rate of the fourth valve; The controller is also configured to correct the opening control of the first valve based on the flow rate detected by the first flow meter, correct the opening control of the second valve based on the flow rate detected by the second flow meter, correct the opening control of the third valve based on the flow rate detected by the third flow meter, and correct the opening control of the fourth valve based on the flow rate detected by the fourth flow meter.

10. An apparatus for synthesizing ammonia, characterized in that, The control system for synthesizing ammonia as described in any one of claims 1-9.

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