Ammonia production system and ammonia production method

Abstract

The application discloses a kind of ammonia production system and ammonia production method, it includes gas compression module, ammonia synthesis module and gas circulation module;Gas compression module includes the gas raw material inlet pipeline, buffer tank, compressor, gas raw material discharge pipeline connected in turn;Gas compression module further includes compressor control unit;Gas circulation module includes heat exchanger, water cooler, circulating machine;Gas circulation module further includes circulating machine control unit;The ammonia production system can be stably operated, and the conversion rate of synthetic ammonia is improved.

Description

Technical Field

[0001] This invention relates to an ammonia production system and ammonia production method. Background Technology

[0002] Liquid ammonia production primarily utilizes fossil fuels such as natural gas and coal. This process emits significant amounts of carbon dioxide per ton of liquid ammonia produced; for example, natural gas-based ammonia production emits as much as 4.2 tons of carbon dioxide per ton of ammonia, and coal-based ammonia production emits the same amount. Green energy ammonia production, on the other hand, uses renewable energy sources (such as solar and wind power) as the energy source and water and air as raw materials, resulting in virtually zero carbon dioxide emissions throughout the entire process.

[0003] Green energy ammonia production is an emerging green chemical process. From green energy to the complete ammonia synthesis process, we are still in the exploratory stage. In order to stabilize the production of green ammonia synthesis units, we need to ensure the stability of the chemical units by stabilizing green electricity.

[0004] Currently, green energy ammonia production still has significant drawbacks. For example, photovoltaic power generation can only generate electricity in stages due to diurnal variations; it is also affected by sunlight and weather conditions, resulting in significant differences in power generation at different times of the day. Wind power generation also varies greatly depending on the wind farm at different times of the day. However, for ammonia synthesis plants (chemical plants), the more stable the raw material supply, the more stable and safer the plant operation. The plant cannot suddenly reduce its load from 100% to 30% or increase it from 30% to 100% in a short period of time; it requires a certain amount of time, but the speed cannot be too fast. In special circumstances, it must be able to operate safely at ultra-low loads of 10%-30%. Existing green energy ammonia production technologies cannot currently solve these problems, thus significantly limiting the large-scale production of green energy ammonia. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the defect of unstable operation of the existing ammonia production system, and to provide an ammonia production system and ammonia production method, which can operate stably and improve the conversion rate of synthetic ammonia.

[0006] The present invention solves the above-mentioned technical problems through the following technical solution:

[0007] This invention provides an ammonia production system, which includes a gas compression module, an ammonia synthesis module, and a gas circulation module;

[0008] The gas compression module includes a gas feedstock inlet pipe, a buffer tank, a compressor, and a gas feedstock outlet pipe connected in sequence; the gas compression module also includes a compressor control unit; a gas feedstock circuit is provided between the gas feedstock outlet pipe and the buffer tank, and a gas feedstock circuit control valve is provided on the gas feedstock circuit; the compressor control unit includes a gas feedstock flow meter provided on the gas feedstock inlet pipe, the gas feedstock flow meter is electrically connected to the frequency converter of the compressor, and the frequency converter of the compressor is electrically connected to the gas feedstock circuit control valve;

[0009] The gas circulation module includes a heat exchanger, a water cooler, and a circulator; the gas circulation module also includes a circulator control unit; the heat exchanger has a first channel and a second channel, the heat exchanger is used to heat the raw material gas in the first channel and output it to the ammonia synthesis module, the second channel, the water cooler, the circulator and the first channel are connected to form a circulating gas regulation channel; the raw material gas discharge pipe is connected to the first channel, the raw material gas discharge pipe is provided with a gas circulation branch and is connected to the pipe between the second channel and the water cooler, the gas circulation branch is provided with a system loop control valve; the upstream and downstream of the circulator are connected through a circulating gas loop, the circulating gas loop is provided with a circulating gas loop control valve; the circulator control unit includes a circulating gas flow meter located on the upstream pipe of the circulator, the circulating gas flow meter is electrically connected to the system loop control valve and the frequency converter of the circulator, the frequency converter of the circulator is electrically connected to the circulating gas loop control valve;

[0010] The ammonia synthesis module is connected to the first channel and is located downstream of the first channel.

[0011] In certain specific embodiments of the present invention, the compressor control unit is used to control the opening and closing degree of the gas raw material circuit control valve and the frequency of the frequency converter according to the flow rate measured by the gas raw material flow meter.

[0012] In certain specific embodiments of the present invention, the circulation machine control unit is used to control the opening and closing degree of the circulation loop control valve, the frequency of the frequency converter of the circulation machine, and the opening and closing degree of the circulation gas loop control valve according to the flow rate measured by the circulation gas flow meter.

[0013] In this invention, preferably, the ammonia synthesis module includes an ammonia synthesis reactor and a waste heat recovery unit; the first channel, the ammonia synthesis reactor, the waste heat recovery unit, and the second channel are connected in sequence.

[0014] In this invention, preferably, a cooling separation device is provided downstream of the water cooler, the cooling separation device being used to separate liquid ammonia.

[0015] Preferably, a water-cooled gas circulation loop is provided between the water cooler and the cooling separation device, and the water-cooled gas circulation loop is used to recover the gas separated by the cooling separation device.

[0016] The present invention also provides a method for producing ammonia, which employs the ammonia production system as described above, the method comprising the following steps:

[0017] The raw material gas is fed into the gas compression module through the gas feed pipe; the raw material gas undergoes an ammonia synthesis reaction in the ammonia synthesis module to generate liquid ammonia; a portion of the raw material gas entering the ammonia synthesis module and the residual gas after passing through the ammonia synthesis module enter the gas circulation module for circulation.

[0018] In this invention, preferably, the compressor control unit operates as follows: a gas feedstock flow meter is used to detect the flow rate of the gas feedstock entering the pipeline in real time, and the frequency of the compressor inverter and the opening and closing degree of the gas feedstock circuit control valve are adjusted according to the detected flow rate until the flow rate detected by the gas feedstock flow meter reaches a set threshold.

[0019] Preferably, the threshold for the flow rate detected by the gas feedstock flow meter is 30%-110% load, more preferably 50%-110% load. Here, 100% load means that, based on the device's capacity, the calculated feedstock gas flow rate is 100% load, 30% of the calculated feedstock gas flow rate is 30% load, and 110% of the calculated feedstock gas flow rate is 110% load.

[0020] Preferably, the compressor control unit operates in the following manner:

[0021] When the flow rate detected by the gas feedstock flow meter is 10%-30% of the load, the frequency of the compressor's inverter and the opening degree of the gas feedstock circuit control valve are increased; when the flow rate detected by the gas feedstock flow meter is 30%-50% of the load, the frequency of the compressor's inverter and the opening degree of the gas feedstock circuit control valve remain unchanged; when the flow rate detected by the gas feedstock flow meter is 50%-110% of the load, the frequency of the compressor's inverter is adjusted accordingly based on the flow rate detected by the gas feedstock flow meter, and the gas feedstock circuit control valve is closed.

[0022] In certain specific embodiments of the present invention, when the flow rate detected by the gas raw material flow meter is above 110% of the load, the gas raw material flow meter displays an overflow alarm and manually intervenes to reduce the supply of hydrogen and nitrogen.

[0023] In this invention, preferably, the circulation machine control unit operates as follows: a circulating gas flow meter is used to detect the flow rate of the upstream pipeline of the circulation machine in real time, and the frequency of the frequency converter of the circulation machine, the opening and closing degree of the system loop control valve and the opening and closing degree of the circulating gas loop control valve are adjusted according to the detected flow rate until the flow rate detected by the gas raw material flow meter reaches a set threshold.

[0024] Preferably, the threshold for the flow rate detected by the circulating gas flow meter is 30%-110% load, and more preferably 50%-110% load. Here, 110% load means that, based on the device's capacity, the calculated circulating gas flow rate is 110% load, and 30% of the calculated circulating gas flow rate is 30% load.

[0025] Preferably, the circulation machine control unit operates in the following manner:

[0026] When the flow rate detected by the circulating gas flow meter is 10%-30% of the load, the frequency of the inverter of the circulating machine is maintained at the minimum control value, and the opening and closing degree of the system loop control valve and the opening and closing degree of the circulating gas loop control valve are increased; wherein, the minimum control value of the frequency of the inverter of the circulating machine means the minimum frequency to maintain the stable operation of the circulating machine.

[0027] When the flow rate detected by the circulating gas flow meter is 30%-50% of the load, the frequency of the inverter of the circulating machine is maintained at the minimum control value, the opening degree of the system loop control valve is increased, and the opening degree of the circulating gas loop control valve is decreased.

[0028] When the flow rate detected by the circulating gas flow meter is 50%-110% of the load, increase the frequency of the inverter of the circulating machine, reduce the opening degree of the system loop control valve, and close the circulating gas loop control valve.

[0029] When the flow rate detected by the circulating gas flow meter is above 110% of the load, the frequency of the inverter of the circulating machine is maintained at the maximum control value, the system loop control valve is closed, and the circulating gas loop control valve is closed; wherein, the maximum control value of the frequency of the inverter of the circulating machine means the maximum frequency to maintain the stable operation of the circulating machine.

[0030] In this invention, preferably, the raw material gas includes nitrogen and hydrogen.

[0031] In this invention, preferably, the range of the gas feedstock flow meter is 0-150% load, more preferably 10%-150% load.

[0032] In this invention, preferably, the range of the circulating air flow meter is 0-150% load, more preferably 10%-150% load.

[0033] In some specific embodiments of the present invention, the temperature of the ammonia synthesis reaction is 350-500°C.

[0034] In certain specific embodiments of the present invention, the time for the ammonia synthesis reaction can be conventional in the art.

[0035] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0036] The reagents and raw materials used in this invention are all commercially available.

[0037] The positive and progressive effects of this invention are as follows:

[0038] The ammonia production system provided by this invention integrates three modules—gas compression module, ammonia synthesis module, and gas circulation module—to form a multi-loop control system. This overcomes the instability of the ammonia production system caused by the unstable flow of raw material gas, improves the safety factor of the ammonia production system, and also increases the conversion rate of synthesized ammonia. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the ammonia production system in Example 1.

[0040] The attached figures are labeled as follows:

[0041] 1-Buffer tank; 2-Compressor; 3-Gas feedstock loop control valve; 4-Gas feedstock flow meter; 5-Compressor frequency converter; 6-Heat exchanger; 7-Water cooler; 8-Circulating machine; 9-System loop control valve; 10-Circulating gas loop control valve; 11-Circulating gas flow meter; 12-Circulating machine frequency converter; 13-Ammonia synthesis reactor; 14-Waste heat recovery unit; 15-Cooling separation device; 16-Product collection device;

[0042] 101-Gas feedstock inlet pipe; 102-Gas feedstock outlet pipe; 103-Gas feedstock circuit; 104-Gas circulation branch; 105-Circulating gas circuit; 106-Water-cooled gas circulation circuit. Detailed Implementation

[0043] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0044] Example 1

[0045] A schematic diagram of the ammonia production system in Example 1 is shown below. Figure 1 As shown.

[0046] It includes a gas compression module, an ammonia synthesis module, and a gas circulation module;

[0047] The gas compression module includes a gas raw material inlet pipe 101, a buffer tank 1, a compressor 2, and a gas raw material outlet pipe 102 connected in sequence; the gas compression module also includes a compressor control unit; a gas raw material circuit 103 is provided between the gas raw material outlet pipe 102 and the buffer tank 1, and a gas raw material circuit control valve 3 is provided on the gas raw material circuit 103; the compressor control unit includes a gas raw material flow meter 4 provided on the gas raw material inlet pipe 101, the gas raw material flow meter 4 is electrically connected to the compressor frequency converter 5, and the compressor frequency converter 5 is electrically connected to the gas raw material circuit control valve 3;

[0048] The gas circulation module includes a heat exchanger 6, a water cooler 7, and a circulator 8; the gas circulation module also includes a circulator control unit; the heat exchanger 6 has a first channel and a second channel, the heat exchanger 6 is used to heat the raw material gas in the first channel and output it to the ammonia synthesis module, the second channel, the water cooler 7, the circulator 8 and the first channel are connected to form a circulating gas regulation channel; the gas raw material discharge pipe 102 is connected to the first channel, the gas raw material discharge pipe 102 is provided with a gas circulation branch 104 and is connected to the pipe between the second channel and the water cooler 7, the gas circulation branch 104 is provided with a system loop control valve 9; the upstream and downstream of the circulator 8 are connected through a circulating gas loop 105, the circulating gas loop 105 is provided with a circulating gas loop control valve 10; the circulator control unit includes a circulating gas flow meter 11 located in the upstream pipe of the circulator 8, the circulating gas flow meter 11 is electrically connected to the system loop control valve 9 and the frequency converter 12 of the circulator, the frequency converter 12 of the circulator is electrically connected to the circulating gas loop control valve 10;

[0049] The ammonia synthesis module is connected to the first channel and is located downstream of the first channel.

[0050] The ammonia synthesis module includes an ammonia synthesis reactor 13 and a waste heat recovery unit 14; the first channel, the ammonia synthesis reactor 13, the waste heat recovery unit 14, and the second channel are connected in sequence.

[0051] Downstream of the water cooler is a cooling separation device 15, which is used to separate liquid ammonia.

[0052] A water-cooled gas circulation loop 106 is also provided between the water cooler and the cooling separation device 15. The water-cooled gas circulation loop 106 is used to recover the gas separated by the cooling separation device 15.

[0053] A product collection device 16 is provided downstream of the cooling separation device 15.

[0054] Example 2

[0055] Example 2 uses the ammonia production system of Example 1.

[0056] The feedstock gases are nitrogen and hydrogen, with the nitrogen to hydrogen flow ratio controlled between 2.8 and 3.2:1. Based on the unit's capacity (20,000 tons / year, 2.5 tons / hour), the calculated feedstock gas flow rate at 100% load is 6600 Nm³. 3 / h.

[0057] The flow rate of the circulating gas at 100% load is: V 循环气 =m 产 *(1+Y 出 ) / Y 出 =2.5*1000*(1+14%) / 14%=20357Nm 3 / h; where V 循环气 The flow rate of the circulating gas is expressed in Nm³. 3 / h,m 产 Y represents the production capacity of the product, expressed in kg / h. 出 The mass content of ammonia at the outlet of the ammonia synthesis reactor, in units of %.

[0058] The ammonia production method includes the following steps:

[0059] The raw material gas is fed into the gas compression module through a gas feed pipeline; after passing through the ammonia synthesis module, the raw material gas is converted into liquid ammonia; part of the raw material gas entering the ammonia synthesis module and the residual gas after passing through the ammonia synthesis module enter the gas circulation module for circulation.

[0060] The threshold for the flow rate detected by the gas feedstock flow meter is 50%-110% of the load;

[0061] The compressor control unit operates as follows:

[0062] When the flow rate detected by the gas feedstock flow meter is 10%-30% of the load, the frequency of the compressor's inverter and the opening degree of the gas feedstock circuit control valve are increased. When the flow rate detected by the gas feedstock flow meter is 30%-50% of the load, the frequency of the compressor's inverter and the opening degree of the gas feedstock circuit control valve remain unchanged. When the flow rate detected by the gas feedstock flow meter is 50%-110% of the load, the frequency of the compressor's inverter is adjusted accordingly based on the flow rate detected by the gas feedstock flow meter, and the gas feedstock circuit control valve is closed. When the flow rate detected by the gas feedstock flow meter is above 110% of the load, the gas feedstock flow meter displays an overflow alarm, and manual intervention is performed to reduce the supply of hydrogen and nitrogen.

[0063] The threshold for the flow rate detected by the circulating air flow meter is 50%-110% of the load;

[0064] The circulation machine control unit operates as follows:

[0065] When the flow rate detected by the circulating gas flow meter is 10%-30% of the load, the frequency of the inverter of the circulating machine is maintained at the minimum control value, and the opening and closing degree of the system loop control valve and the circulating gas loop control valve are increased; where the minimum control value of the frequency of the inverter of the circulating machine means the minimum frequency to maintain the stable operation of the circulating machine.

[0066] When the flow rate detected by the circulating gas flow meter is 30%-50% of the load, maintain the frequency of the frequency converter of the circulating machine at the minimum control value, increase the opening degree of the system loop control valve, and decrease the opening degree of the circulating gas loop control valve.

[0067] When the flow rate detected by the circulating gas flow meter is 50%-110% of the load, increase the frequency of the inverter of the circulating machine, reduce the opening and closing degree of the system loop control valve, and close the circulating gas loop control valve.

[0068] When the flow rate detected by the circulating gas flow meter is above 110% of the load, the frequency of the inverter of the circulating machine is maintained at the maximum control value, the system loop control valve is closed, and the circulating gas loop control valve is closed; where the maximum control value of the frequency of the inverter of the circulating machine means the maximum frequency to maintain the stable operation of the circulating machine.

[0069] After passing through the ammonia synthesis module, the raw material gas undergoes a synthesis reaction to produce liquid ammonia. The temperature of the ammonia synthesis reaction is 350-500°C. The gas after the reaction is cooled and condensed to separate liquid ammonia. The unreacted gas enters the gas circulation module, where it is pressurized by the compressor and participates in the reaction again.

[0070] The range of the gas feedstock flow meter is 10%-150% load, and the range of the circulating gas flow meter is 10%-150% load.

[0071] Using the above-described apparatus and method, the system can automatically adjust in real time between 30% and 110% load, ensuring stable operation. Furthermore, the method of this invention allows for stable operation even at 10% to 30% load, enabling production to resume at any time. While ensuring stable operation, the above-described apparatus and method can tolerate hydrogen and nitrogen fluctuations exceeding 3% / min.

[0072] Comparative Example 1

[0073] The ammonia production system of Comparative Example 1 does not contain a compressor control unit, that is, it includes a gas compression module, an ammonia synthesis module and a gas circulation module; the gas compression module includes a gas feedstock inlet pipe, a buffer tank, a compressor and a gas feedstock outlet pipe connected in sequence, and the gas feedstock outlet pipe is connected to the first channel of the heat exchanger; the rest of the structure is the same as that of Example 1.

[0074] The type and flow rate of the raw material gas in Comparative Example 1 are the same as those in Example 2, and the ammonia production system described above is used.

[0075] Using the device and method of Comparative Example 1, even if the compressor circuit itself, i.e. the compressor control unit, is turned on under ultra-low load of 10%-30%, it cannot meet the actual situation, and the device cannot continue to operate and can only be shut down.

[0076] Comparative Example 2

[0077] The ammonia production system of Comparative Example 2 does not contain a circulation control unit, that is, it includes a gas compression module, an ammonia synthesis module and a gas circulation module; the gas circulation module does not have a circulating gas loop, and the rest of the structure is the same as that of Example 1.

[0078] The type and flow rate of the raw material gas in Comparative Example 2 are the same as those in Example 2, and the ammonia production system described above is used.

[0079] Using the apparatus and method of Comparative Example 2, the pressure of the entire system also drops significantly under ultra-low loads of 10%-30%. As a result of the drop, the single-pass hydrogen conversion rate is low, and the heat released by the reaction is divided into two parts. One part is carried away by thermal radiation (this part of the heat loss is basically fixed), and the other part of the heat is carried out of the ammonia synthesis reactor by the reaction gas. Due to the reduced load of the apparatus, the heat of reaction cannot meet the needs of these two parts of heat removal, and the temperature of the catalytic bed in the ammonia synthesis reactor will collapse.

[0080] Using the apparatus and method of this invention, the single-pass hydrogen conversion efficiency, power consumption, and heat recovery of the apparatus are consistent with those of conventional ammonia plants in the prior art, within a load range of 30%-110%. Generally, when increasing or decreasing the load of conventional plants, if the fluctuations in hydrogen and nitrogen exceed 3% / min, planned contingency measures are required in advance. However, with the high amplitude and high frequency fluctuations of green energy, the unpredictability in the short term often causes hydrogen and nitrogen fluctuations to exceed 3% / min, leading to unstable operation of the plant. With the control system of this invention, real-time automatic adjustment can be achieved, enabling stable operation of the plant. Furthermore, with the method of this invention, the plant can also operate stably under loads of 10%-30%, allowing for immediate resumption of production.

[0081] Compared with Comparative Example 1, Example 2 can ensure stable operation of the device even under ultra-low loads of 10%-30%, keeping the device in a hot state and allowing it to quickly resume full-load production at any time based on the conditions of nitrogen and hydrogen at the front end.

[0082] Compared with Comparative Example 2, under ultra-low loads of 10%-30%, Example 2 reduces the gas flow rate in the ammonia synthesis reactor, thereby reducing the corresponding reaction gas flow rate and increasing the total gas flow rate of the entire system. This creates a pressure-forcing effect, increasing the system pressure and improving the hydrogen conversion efficiency within the ammonia synthesis reactor. Simultaneously, due to the reduced inlet gas flow rate of the ammonia synthesis reactor, the heat carried away by the reaction gas is reduced, effectively retaining the reaction heat within the ammonia synthesis reaction tower. This effectively solves the temperature drop problem in the catalytic bed of the ammonia synthesis reactor and prepares for a rapid increase in the unit's production load in the future.

Claims

1. An ammonia production system, characterized in that, It includes a gas compression module, an ammonia synthesis module, and a gas circulation module; The gas compression module includes a gas feedstock inlet pipe, a buffer tank, a compressor, and a gas feedstock outlet pipe connected in sequence; the gas compression module also includes a compressor control unit; a gas feedstock circuit is provided between the gas feedstock outlet pipe and the buffer tank, and a gas feedstock circuit control valve is provided on the gas feedstock circuit; the compressor control unit includes a gas feedstock flow meter provided on the gas feedstock inlet pipe, the gas feedstock flow meter is electrically connected to the frequency converter of the compressor, and the frequency converter of the compressor is electrically connected to the gas feedstock circuit control valve; The gas circulation module includes a heat exchanger, a water cooler, and a circulator; the gas circulation module also includes a circulator control unit; the heat exchanger has a first channel and a second channel, the heat exchanger is used to heat the raw material gas in the first channel and output it to the ammonia synthesis module, the second channel, the water cooler, the circulator and the first channel are connected to form a circulating gas regulation channel; the raw material gas discharge pipe is connected to the first channel, the raw material gas discharge pipe is provided with a gas circulation branch and is connected to the pipe between the second channel and the water cooler, the gas circulation branch is provided with a system loop control valve; the upstream and downstream of the circulator are connected through a circulating gas loop, the circulating gas loop is provided with a circulating gas loop control valve; the circulator control unit includes a circulating gas flow meter located on the upstream pipe of the circulator, the circulating gas flow meter is electrically connected to the system loop control valve and the frequency converter of the circulator, the frequency converter of the circulator is electrically connected to the circulating gas loop control valve; The ammonia synthesis module is connected to the first channel and is located downstream of the first channel.

2. The ammonia production system as described in claim 1, characterized in that, The ammonia synthesis module includes an ammonia synthesis reactor and a waste heat recovery unit; the first channel, the ammonia synthesis reactor, the waste heat recovery unit, and the second channel are connected in sequence.

3. The ammonia production system as described in claim 1, characterized in that, Downstream of the water cooler is a cooling separation device used to separate liquid ammonia.

4. The ammonia production system as described in claim 3, characterized in that, A water-cooled gas circulation loop is also provided between the water cooler and the cooling separation device, which is used to recover the gas separated by the cooling separation device.

5. A method for producing ammonia, characterized in that, It employs an ammonia production system as described in any one of claims 1-4, and the ammonia production method includes the following steps: The raw material gas is fed into the gas compression module through the gas feed pipe; the raw material gas undergoes an ammonia synthesis reaction in the ammonia synthesis module to generate liquid ammonia; a portion of the raw material gas entering the ammonia synthesis module and the residual gas after passing through the ammonia synthesis module enter the gas circulation module for circulation.

6. The ammonia production method as described in claim 5, characterized in that, The compressor control unit operates as follows: a gas feedstock flow meter is used to detect the flow rate of the gas feedstock entering the pipeline in real time. Based on the detected flow rate, the frequency of the compressor's frequency converter and the opening and closing degree of the gas feedstock circuit control valve are adjusted until the flow rate detected by the gas feedstock flow meter reaches a set threshold.

7. The ammonia production method as described in claim 6, characterized in that, The threshold for the flow rate detected by the gas feedstock flow meter is 30%-110% of the load; The compressor control unit operates in the following manner: When the flow rate detected by the gas feedstock flow meter is 10%-30% of the load, the frequency of the compressor's inverter and the opening degree of the gas feedstock circuit control valve are increased; when the flow rate detected by the gas feedstock flow meter is 30%-50% of the load, the frequency of the compressor's inverter and the opening degree of the gas feedstock circuit control valve remain unchanged; when the flow rate detected by the gas feedstock flow meter is 50%-110% of the load, the frequency of the compressor's inverter is adjusted accordingly based on the flow rate detected by the gas feedstock flow meter, and the gas feedstock circuit control valve is closed.

8. The ammonia production method as described in claim 5, characterized in that, The circulation machine control unit operates as follows: a circulating gas flow meter is used to detect the flow rate of the upstream pipeline of the circulation machine in real time. Based on the detected flow rate, the frequency of the frequency converter of the circulation machine, the opening and closing degree of the system loop control valve, and the opening and closing degree of the circulating gas loop control valve are adjusted until the flow rate detected by the gas raw material flow meter reaches the set threshold.

9. The ammonia production method as described in claim 8, characterized in that, The threshold for the flow rate detected by the circulating air flow meter is 30%-110% of the load; The circulation machine control unit operates in the following manner: When the flow rate detected by the circulating gas flow meter is 10%-30% of the load, the frequency of the inverter of the circulating machine is maintained at the minimum control value, and the opening and closing degree of the system loop control valve and the opening and closing degree of the circulating gas loop control valve are increased; wherein, the minimum control value of the frequency of the inverter of the circulating machine means the minimum frequency to maintain the stable operation of the circulating machine. When the flow rate detected by the circulating gas flow meter is 30%-50% of the load, the frequency of the inverter of the circulating machine is maintained at the minimum control value, the opening degree of the system loop control valve is increased, and the opening degree of the circulating gas loop control valve is decreased. When the flow rate detected by the circulating gas flow meter is 50%-110% of the load, increase the frequency of the inverter of the circulating machine, reduce the opening degree of the system loop control valve, and close the circulating gas loop control valve. When the flow rate detected by the circulating gas flow meter is above 110% of the load, the frequency of the inverter of the circulating machine is maintained at the maximum control value, the system loop control valve is closed, and the circulating gas loop control valve is closed; wherein, the maximum control value of the frequency of the inverter of the circulating machine means the maximum frequency to maintain the stable operation of the circulating machine.

10. The ammonia production method according to claim 5, characterized in that, The ammonia production method satisfies one or more of the following conditions: (a) The raw material gas includes nitrogen and hydrogen; (b) The range of the gas feedstock flow meter is 0-150% load; (c) The range of the circulating air flow meter is 0-150% load.

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