Renewable energy multistable ammonia synthesis system, control method and process

Abstract

The invention relates to the technical field of ammonia synthesis, and provides a renewable energy multistable ammonia synthesis system, a control method and a process. The production subsystem comprises a renewable energy power generation module; a hydrogen-nitrogen gas module; the ammonia synthesis module comprises an ammonia synthesis tower, a cooling separation unit, a temperature regulation unit and a circulator; the temperature adjusting unit is used for adjusting inlet gas temperature of the ammonia synthesis tower; the hydrogen-nitrogen module is connected with an inlet of the ammonia synthesis tower through the circulator; an inlet of the cooling separation unit is connected with an outlet of the ammonia synthesis tower, and a gas outlet is connected to an inlet of the ammonia synthesis tower through a gas loop and a circulator; the ammonia cooling module is used for providing cooling capacity for the cooling separation unit; the ammonia spraying module is used for adjusting the ammonia content of the inlet gas of the ammonia synthesis tower. Thus, rapid adjustment in the whole production load range can be achieved, safe and stable operation of equipment under the low production load is guaranteed, and the green ammonia production process adapts to the characteristics of renewable energy source volatility and randomness.

Description

Technical Field

[0001] The present invention relates to the technical field of synthetic ammonia, and in particular to a renewable energy multi-stable-state synthetic ammonia system, a control method and a process. Background Art

[0002] The development of renewable energy (wind / solar) has become a rigid demand and will become the main force of energy supply in the future, with a certain and broad market in the short and medium term. However, renewable energy generation is characterized by volatility and randomness, and its large-scale grid connection will bring a great impact to the power grid, threatening the safety and stability of the power system. Renewable energy (hydrogen production) synthetic ammonia (green ammonia) is one of the large-scale consumption methods of renewable energy such as wind / solar power generation, and is also one of the important technical routes for traditional chemical processes to achieve low-carbon and clean development.

[0003] The current difficulty and pain point of the green ammonia production process lies in the contradiction between the fluctuating output of the power supply (renewable energy) and the "safe, stable, long-term, full and optimal" operation requirements of the load side (traditional ammonia synthesis process). "Source-load mismatch" will lead to the following problems: 1) Unbalanced electricity between source and load: When the output of renewable energy changes rapidly (in seconds), the production load regulation of the green ammonia unit lags behind (usually in hours), resulting in power abandonment at the power source end (source > load) or power shortage at the load end (source < load) and emergency shutdown.

[0004] 2) When adjusting the production load of traditional synthetic ammonia, two problems will be faced: (1) The production load adjustment range is limited. The traditional ammonia synthesis module is generally 50~110%. It is generally believed that it cannot operate continuously and stably at a production load of ≤30%, resulting in limited matching space between power supply and load.

[0005] (2) When adjusting the production load of traditional synthetic ammonia, it is achieved by adjusting the air velocity (i.e., the circulating gas flow rate) and the system pressure, so the production load depends on the pressure. According to Formula 4-18-60 in the Fertilizer Engineering Series on Synthetic Ammonia: It can be seen that when synthetic ammonia is at a low production load (such as 35%), the system pressure will drop to 7.5MPa (the system pressure is 14MPa at 100% production load). For synthetic ammonia with renewable energy, especially when the power source is mainly photovoltaic, the ammonia synthesis module is bound to be at full load (100%) during the day, low production load (35% or even lower) at night (no photovoltaic output), and return to full load production status during the next day. Such a cycle will inevitably cause all equipment in the ammonia synthesis module to experience at least one pressure cycle of 14MPa→7.5MPa→14MPa every day. Fatigue analysis and anti-fatigue design must be carried out in accordance with Article 3.10.2.1 a of the "Steel Pressure Vessel-Analysis and Design Standard" (JB4732-95); or the design pressure of all equipment in the ammonia synthesis module must be greatly increased to 40MPa. Both anti-fatigue design and increased design pressure will lead to a significant increase in the manufacturing cost of ammonia synthesis module equipment.

[0006] Therefore, how to make the green ammonia production process truly adapt to the volatility and randomness of renewable energy is an important issue that needs to be solved urgently. Summary of the invention

[0007] The present invention provides a renewable energy multi-stable ammonia synthesis system, a control method and a process, which are used to solve the problem that the green ammonia production process in the prior art is difficult to adapt to the volatility and randomness of renewable energy output, can achieve rapid adjustment within the full production load range, and ensure safe and stable operation of the equipment at low production loads, so that the green ammonia production process can truly adapt to the volatility and randomness of renewable energy.

[0008] The present invention provides a renewable energy multi-stable ammonia synthesis system, comprising: a production subsystem; the production subsystem comprises: A renewable energy generation module for generating renewable electricity; A hydrogen and nitrogen module, used to prepare nitrogen and hydrogen required for synthesizing ammonia using the renewable electricity; An ammonia synthesis module comprises an ammonia synthesis tower, a cooling and separation unit, a temperature regulating unit and a circulation machine; the temperature regulating unit is used to regulate the temperature of the inlet gas of the ammonia synthesis tower; the hydrogen and nitrogen module is connected to the inlet of the ammonia synthesis tower through the circulation machine; the inlet of the cooling and separation unit is connected to the outlet of the ammonia synthesis tower, and the gas outlet is connected to the inlet of the ammonia synthesis tower through the gas loop and the circulation machine; An ammonia cooling module, used to provide cooling capacity for the cooling and separation unit; The ammonia injection module is used to adjust the ammonia content of the inlet gas of the ammonia synthesis tower.

[0009] According to a renewable energy multi-stable ammonia synthesis system provided by the present invention, the production subsystem further includes an energy storage module and a waste heat power generation module; The energy storage module is used to store renewable electricity; The waste heat power generation module includes a waste heat recovery unit and a waste heat power generation unit; the waste heat recovery unit is connected to the outlet of the ammonia synthesis tower and is used to recover waste heat in the gas product; the waste heat power generation unit uses the waste heat recovered by the waste heat recovery unit to generate electricity.

[0010] According to a renewable energy multi-stable ammonia synthesis system provided by the present invention, the cooling and separation unit comprises a water cooler, a primary ammonia separator, an ammonia cooler and a secondary ammonia separator connected in sequence; The outlet of the ammonia synthesis tower is connected to the inlet of the water cooler after passing through the waste heat recovery unit and the heat exchanger in sequence, and the outlet of the water cooler is connected to the inlet of the primary ammonia separator; The gas outlet of the primary ammonia separator is connected to the inlet of the secondary ammonia separator through the ammonia cooler, and an XV-1 valve is provided between the primary ammonia separator and the ammonia cooler; The liquid ammonia outlets of the primary ammonia separator and the secondary ammonia separator are connected to the ammonia injection module after being merged; The gas outlet of the secondary ammonia separator is connected to the circulation machine via the gas loop; The ammonia cooling module is used to provide cooling capacity for the ammonia cooler.

[0011] According to a renewable energy multi-stable ammonia synthesis system provided by the present invention, the production subsystem further includes a public auxiliary module; the public auxiliary module includes an emergency power generation unit; The gas outlet of the primary ammonia separator is connected to the circulation machine through a hot standby loop, and the hot standby loop is connected to an XV-2 valve.

[0012] According to a renewable energy multi-stable ammonia synthesis system provided by the present invention, the cooling and separation unit also includes a cold exchanger arranged between the primary ammonia separator and the ammonia cooler, and the gas outlet of the secondary ammonia separator is connected to the cold exchanger to provide a cold source for the cold exchanger.

[0013] According to a renewable energy multi-stable ammonia synthesis system provided by the present invention, the temperature adjustment unit includes an electric heater; The heat flow inlet of the heat exchanger is connected to the outlet of the ammonia synthesis tower, and the heat flow outlet is connected to the cooling and separation unit; The cold flow inlet of the heat exchanger is connected to the circulation machine, and the cold flow outlet is connected to the electric heater through a temperature control main circuit and connected to the inlet of the ammonia synthesis tower through a temperature control branch circuit; the outlet of the electric heater is connected to the inlet of the ammonia synthesis tower.

[0014] According to a renewable energy multi-stable ammonia synthesis system provided by the present invention, a multi-point ammonia injection unit is arranged before the inlet of the ammonia synthesis tower; The ammonia spray module includes an ammonia spray tank and an ammonia spray pump; the inlet of the ammonia spray tank is connected to the liquid ammonia outlet of the cooling and separation unit, and the outlet is connected to the multi-point ammonia spray unit through the ammonia spray pump; Alternatively, the ammonia injection module includes a liquid ammonia storage tank and an ammonia injection pump; the inlet of the liquid ammonia storage tank is connected to the liquid ammonia outlet of the cooling and separation unit, and the outlet is connected to the multi-point ammonia injection unit through the ammonia injection pump.

[0015] According to a renewable energy multi-stable ammonia synthesis system provided by the present invention, the hydrogen-nitrogen module comprises a nitrogen production unit, an electrolytic hydrogen production unit, a hydrogen-nitrogen compressor and a hydrogen-nitrogen ratio adjustment unit; The nitrogen production unit, the electrolytic hydrogen production unit and the hydrogen and nitrogen compressor all adopt a configuration of basic load plus adjustment load.

[0016] According to a renewable energy multi-stable ammonia synthesis system provided by the present invention, the ammonia cooling module includes a basic refrigeration device and a regulating refrigeration device.

[0017] According to a renewable energy multi-stable ammonia synthesis system provided by the present invention, the production subsystem further includes a data acquisition module, and the data acquisition module includes: A temperature monitoring unit, used to monitor the gas inlet / outlet temperature of the ammonia synthesis tower; A pressure monitoring unit, used to monitor the gas inlet pressure of the ammonia synthesis tower; A flow monitoring unit, used to monitor the flow of the hydrogen and nitrogen modules and the circulating gas flow; A liquid level monitoring unit, used to monitor the liquid level of liquid ammonia in the ammonia injection module; The component monitoring unit is used to monitor the ammonia content of the inlet gas of the ammonia synthesis tower.

[0018] According to a renewable energy multi-stable ammonia synthesis system provided by the present invention, each valve in the production subsystem is interlocked and controlled with the data acquisition module.

[0019] A renewable energy multi-stable ammonia synthesis system provided by the present invention further includes a control subsystem; the control subsystem includes: The basic process control module is pre-set with multiple steady-state working conditions corresponding to different production loads, and control parameters of each module in the production subsystem corresponding to different steady-state working conditions; Other control modules are used to predict the amount of renewable electricity at different time scales, where the amount of renewable electricity includes the amount of electricity generated by the renewable energy generation module and the amount of electricity stored by the energy storage module; The multi-stable scheduling module has a built-in comprehensive power consumption corresponding to several steady-state operating conditions. The adjustment direction is determined according to the amount of renewable electricity predicted by other control modules and the comprehensive power consumption. When the difference is positive, the control parameters of the next-level steady-state operating condition in the basic process module are called to adjust the current steady-state operating condition to the next-level steady-state operating condition. When the difference is negative, the control parameters of the previous-level steady-state operating condition in the basic process module are called to adjust the current steady-state operating condition to the previous-level steady-state operating condition. When the difference is zero, the current steady-state operating condition is maintained.

[0020] The present invention also provides a production process of renewable energy multi-stable ammonia synthesis, which is applicable to any one of the renewable energy multi-stable ammonia synthesis systems described above; When the output of the renewable energy power generation module changes, the gas parameters (temperature, pressure, flow rate, ammonia content) at the outlet of the ammonia synthesis tower are maintained. ) remain unchanged, adjust the inlet gas parameters of the ammonia synthesis tower (temperature and ammonia content ) to change the degree to which the inlet gas of the ammonia synthesis tower approaches the reaction equilibrium, thereby adjusting the net ammonia value at the inlet and outlet of the ammonia synthesis tower.

[0021] According to a production process of renewable energy multi-stable ammonia synthesis provided by the present invention, when the renewable energy power generation module has no output for a short time, the hydrogen nitrogen module and the ammonia cooling module are turned off, the XV-1 valve is closed, the XV-2 valve is opened, and the liquid ammonia at the outlets of the primary ammonia separator and the secondary ammonia separator are all returned to the inlet of the ammonia synthesis tower through the ammonia injection module, thereby realizing a short-term hot standby function; The electricity required for short-term hot standby is provided jointly by the energy storage module and the waste heat power generation module.

[0022] According to a production process of renewable energy multi-stable ammonia synthesis provided by the present invention, when the renewable energy power generation module has no output for a long time, the hydrogen nitrogen module and the ammonia cooling module are turned off, the XV-1 valve is opened, the XV-2 valve is closed, and the circulating gas is directly returned to the inlet of the circulating machine after passing through the water cooler and the first-level ammonia separator in sequence, and the liquid ammonia at the outlet of the first-level ammonia separator is all returned to the inlet of the ammonia synthesis tower through the ammonia injection module, so as to realize the long-term hot standby function; The cold exchanger, ammonia cooling module, and primary ammonia separator are in shutdown state; The electricity required for long-term hot standby is jointly provided by the emergency power generation unit, energy storage module and waste heat power generation module of the public auxiliary module.

[0023] The present invention also provides a control method for a renewable energy multi-stable ammonia synthesis system, comprising the following steps: Divide the multi-level steady-state working conditions step by step according to different production loads, and determine the control parameters of each module in the production subsystem under different levels of steady-state working conditions and the comprehensive power consumption of the production subsystem; At preset time intervals, predict the amount of renewable electricity at different time scales, where the amount of renewable electricity includes the amount of electricity generated by the renewable energy power generation module and the amount of electricity stored by the energy storage module; Determine the adjustment direction according to the difference between the amount of renewable electricity and the corresponding comprehensive power consumption under the current steady-state condition; When the difference is positive, the current steady-state operating condition is adjusted to the next level steady-state operating condition. When the difference is negative, the current steady-state operating condition is adjusted to the previous level steady-state operating condition. When the difference is zero, the current steady-state operating condition is maintained.

[0024] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, a control method for a renewable energy multi-stable ammonia synthesis system as described in any one of the above-mentioned methods is implemented.

[0025] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements a control method for a renewable energy multi-stable ammonia synthesis system as described in any one of the above.

[0026] The present invention also provides a computer program product, comprising a computer program, which, when executed by a processor, implements the control method of any one of the above-mentioned renewable energy multi-stable ammonia synthesis systems.

[0027] The renewable energy multi-stable ammonia synthesis system and control method provided by the present invention ensures that the circulating gas flow rate in the ammonia synthesis module remains unchanged through the circulation machine when the output of the renewable energy power generation module changes, thereby avoiding fatigue analysis and anti-fatigue design caused by pressure reduction of each device of the ammonia synthesis module when the production load is low; by maintaining the gas parameters (temperature, pressure, flow, ammonia content) at the outlet of the ammonia synthesis tower ) remain unchanged, so that the operating parameters of the subsequent equipment of the ammonia synthesis tower remain unchanged, and only the inlet gas parameters of the ammonia synthesis tower (temperature, ammonia content) are adjusted. ), to change the degree to which the inlet gas of the ammonia synthesis tower approaches the reaction equilibrium (chemical thermodynamics), thereby changing the net ammonia value of the inlet and outlet of the ammonia synthesis tower ( = - ), assisted by the joint regulation of the hydrogen-nitrogen module and the ammonia cooling module, the ammonia synthesis module can be quickly adjusted within the full production load range (0~110%), which is simple to operate and easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 It is a schematic diagram of the structure of a renewable energy multi-stable ammonia synthesis system provided in an embodiment of the present invention.

[0030] Figure 2 It is a working principle diagram of the control subsystem provided by an embodiment of the present invention.

[0031] Figure 3 It is a flow chart of a control method of a renewable energy multi-stable ammonia synthesis system provided by an embodiment of the present invention.

[0032] Figure 4 It is a schematic diagram of the structure of an electronic device provided by an embodiment of the present invention.

[0033] Reference numerals: 1. Production subsystem; 1-10. Renewable energy power generation module; 1-20. Hydrogen and nitrogen module; 1-210. Nitrogen production unit; 1-220. Electrolytic hydrogen production unit; 1-230. Hydrogen and nitrogen compressor; 1-30. Ammonia synthesis module; 1-300. Ammonia synthesis tower; 1-301. Multi-point ammonia injection unit; 1-310. Circulator; 1-320. Water cooler; 1-321. Primary ammonia separator; 1-322. Ammonia cooler; 1-323. Secondary ammonia separator; 1-324. Liquid ammonia main line; 1-325. XV4 valve; 1-326. Liquid ammonia branch line; 1-327. XV3 valve; 1-328. Cold exchanger; 1-330. Heat exchanger; 1-331. Electric heater; 1-332, temperature control main circuit; 1-333, temperature control branch circuit; 1-334, TV3 valve; 1-335, TV2 valve; 1-336, hot standby circuit; 1-337, XV2 valve; 1-338, XV1 valve; 1-40, ammonia injection module; 1-410, ammonia injection tank; 1-420, ammonia injection pump; 1-430, ammonia injection pipeline; 1-440, TV1 valve; 1-50, ammonia cooling module; 1-60, waste heat recovery unit; 1-61, waste heat power generation unit; 1-70, energy storage module; 1-80, public auxiliary module; 2, control subsystem; 2-10, basic process control module; 2-11, other control modules; 2-12, multi-stable scheduling module. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] In order to facilitate the understanding of the renewable energy multi-stable ammonia synthesis system, control method and process provided by the present invention, its application background is first introduced. With the global emphasis on reducing greenhouse gas emissions and achieving the "dual carbon" goal, renewable energy such as wind energy and solar energy have gradually become the main sources of energy supply. However, these energy sources have obvious volatility and intermittency, which poses a challenge to the stable operation of the power system. Especially when accessing the power grid on a large scale, how to effectively absorb these unstable power sources has become an urgent problem to be solved.

[0036] Green ammonia (ammonia synthesized from nitrogen and hydrogen produced by renewable energy) is considered as an effective way to solve the above problems as a clean energy carrier. It not only helps to improve the utilization rate of renewable energy, but also promotes the green transformation of the chemical industry.

[0037] However, the existing green ammonia production technology faces the problem of poor matching between the power supply end and the load end: 1) Unbalanced electricity between source and load: When the output of renewable energy changes rapidly (in seconds), the production load regulation of the green ammonia unit lags behind (usually in hours), resulting in power abandonment at the power source end (source > load) or power shortage at the load end (source < load) and emergency shutdown.

[0038] 2) The traditional ammonia synthesis process is difficult to operate stably under low load, which limits its ability to adapt to changes in renewable energy output.

[0039] 3) When adjusting the production load of traditional synthetic ammonia, it is achieved by adjusting the space velocity (i.e., circulating gas flow) and system pressure. Therefore, the production load depends on the pressure. Frequent pressure changes will accelerate equipment aging, increase maintenance costs and safety hazards. At the same time, in order to adapt to these changes, the equipment may require higher design standards, thereby increasing the initial investment cost.

[0040] In view of the above problems, the present invention provides a renewable energy multi-stable ammonia synthesis system, control method and process, which can achieve rapid adjustment within the full production load range, ensure safe and stable operation of the equipment at low production load, and realize short-term / long-term hot standby function, so that the green ammonia production process can truly adapt to the volatility and randomness of renewable energy.

[0041] Combine the following Figure 1-Figure 4The invention describes a renewable energy multi-stable ammonia synthesis system, a control method and a process.

[0042] Reference Figure 1 A renewable energy multi-stable ammonia synthesis system includes a production subsystem 1, the production subsystem 1 includes a renewable energy power generation module 1-10, a hydrogen-nitrogen module 1-20, an ammonia synthesis module 1-30, an ammonia cooling module 1-50 and an ammonia injection module 1-40; wherein the renewable energy power generation module 1-10 is used to generate renewable electricity; the hydrogen-nitrogen module 1-20 is used to use the renewable electricity generated by the renewable energy power generation module 1-10 to prepare nitrogen and hydrogen required for synthesizing ammonia.

[0043] The ammonia synthesis module 1-30 includes an ammonia synthesis tower 1-300, a cooling and separation unit, a temperature control unit and a circulation machine 1-310; wherein the ammonia synthesis tower 1-300 is a device for synthesizing ammonia from hydrogen and nitrogen; the hydrogen-nitrogen module 1-20 is connected to the inlet of the ammonia synthesis tower 1-300 through the circulation machine 1-310, and the inlet of the cooling and separation unit is connected to the outlet of the ammonia synthesis tower 1-300, which is used to cool the ammonia in the gas product into liquid ammonia and separate it, and the gas outlet of the cooling and separation unit is connected to the inlet of the ammonia synthesis tower 1-300 through the gas loop and the circulation machine 1-310; the ammonia cooling module 1-50 is used to provide cooling capacity for the cooling and separation unit, and the ammonia injection module 1-40 is used to adjust the ammonia content of the inlet gas of the ammonia synthesis tower 1-300.

[0044] In actual operation, the hydrogen-nitrogen module 1-20 uses the renewable electricity generated by the renewable energy power generation module 1-10 to prepare hydrogen and nitrogen. The hydrogen and nitrogen are introduced into the ammonia synthesis tower 1-300 through the circulation machine 1-310 to react and synthesize ammonia. The gas product discharged from the outlet of the ammonia synthesis tower 1-300 enters the cooling and separation unit. The cooling and separation unit can cool the ammonia in the gas product into liquid ammonia and separate it. The gas outlet of the cooling and separation unit is connected to the inlet of the ammonia synthesis tower 1-300 through the gas loop and the circulation machine 1-310, so that the gas separated by the cooling and separation unit can flow back to the ammonia synthesis tower 1-300 to react and form circulating gas; the gas flow in the ammonia synthesis module 1-30 can be adjusted by the circulation machine 1-310, and the temperature of the gas entering the inlet of the ammonia synthesis tower 1-300 can be adjusted by the temperature control unit; the ammonia injection module 1-40 can spray liquid ammonia into the inlet of the ammonia synthesis tower 1-300, thereby adjusting the ammonia content of the inlet gas of the ammonia synthesis tower 1-300.

[0045] When the output of the renewable energy power generation module 1-10 changes, the circulating gas flow rate in the ammonia synthesis module 1-30 is kept constant through the circulating machine 1-310, thereby avoiding fatigue analysis and anti-fatigue design caused by pressure reduction of each device in the ammonia synthesis module 1-30 when the production load is low; by maintaining the outlet gas parameters (temperature, pressure, flow, ammonia content) of the ammonia synthesis tower 1-300 ) remains unchanged, so that the operating parameters of the subsequent equipment of the ammonia synthesis tower 1-300 do not change, and only the inlet gas parameters (temperature, ammonia content) of the ammonia synthesis tower 1-300 are adjusted. ), to change the degree to which the inlet gas of the ammonia synthesis tower 1-300 approaches the reaction equilibrium (chemical thermodynamics), thereby changing the net value of ammonia inlet and outlet of the ammonia synthesis tower 1-300 ( = - ), assisted by the joint regulation of the hydrogen-nitrogen module 1-20 and the ammonia cooling module 1-50, the ammonia synthesis module 1-30 can be quickly adjusted within the full production load (0~110%) range, which is simple to operate and easy to implement.

[0046] It should be noted here that the outlet gas parameters (temperature, pressure, flow rate, ammonia content) of the ammonia synthesis tower 1-300 ) is maintained unchanged by: 1) When the ammonia synthesis process, the structure of the ammonia synthesis tower 1-300, the type of ammonia synthesis catalyst and the production stage (early, middle and late stages) are determined, the ammonia content of the outlet gas That is, it is a constant, which can be calculated by reaction thermodynamics and equilibrium temperature distance ΔT. ΔT is determined by thermodynamics (equilibrium temperature curve), catalyst performance (optimal temperature curve), and the structural form of the ammonia synthesis tower 1-300.

[0047] 2) When adjusting the production load of the ammonia synthesis module 1-30, by maintaining the rotation speed of the circulation machine 1-310 unchanged, it can be ensured that the circulating gas flow in the ammonia synthesis module 1-30 does not change basically, and the operating pressure of each equipment can be kept stable, avoiding fatigue analysis and anti-fatigue design.

[0048] 3) When the circulating gas flow rate in the ammonia synthesis module 1-30 remains unchanged, the operating pressure of each device remains basically unchanged, thereby ensuring that the outlet gas pressure of the ammonia synthesis tower 1-300 remains unchanged.

[0049] 4) When the circulating gas flow rate remains unchanged, the outlet gas temperature of the ammonia synthesis tower 1-300 can be kept constant by adjusting the inlet ammonia injection amount, thereby ensuring that all subsequent equipment of the ammonia synthesis tower 1-300 can maintain relatively stable operating parameters.

[0050] Gas parameters at the inlet of ammonia synthesis tower 1-300 (temperature, ammonia content ) is adjusted in the following way: 1) The temperature of the gas at the inlet of the ammonia synthesis tower 1-300 can be adjusted by the temperature control unit.

[0051] 2) By adjusting the amount of ammonia sprayed from the ammonia spray module 1-40 to the inlet of the ammonia synthesis tower 1-300, the ammonia content of the inlet gas of the ammonia synthesis tower 1-300 can be adjusted. .

[0052] By adopting the above technical solution, rapid adjustment can be achieved within the entire production load range, and safe and stable operation of the equipment can be ensured at low production loads.

[0053] According to different needs and application scenarios, the renewable energy power generation module 1-10 and the hydrogen and nitrogen module 1-20 can be configured in different forms.

[0054] In one embodiment of the present invention, the renewable energy generation module 1-10 uses wind / solar power generation equipment. It should be noted that the specific structure and working principle of the wind or solar power generation equipment can refer to the prior art and will not be described in detail in the embodiment of the present invention.

[0055] The hydrogen-nitrogen module 1-20 includes a nitrogen production unit 1-210, an electrolytic hydrogen production unit 1-220, a hydrogen-nitrogen compressor 1-230, and a hydrogen-nitrogen ratio adjustment unit. Among them, the nitrogen production unit 1-210, the electrolytic hydrogen production unit 1-220, and the hydrogen-nitrogen compressor 1-230 (group) all adopt a typical configuration of 1+N (1 is the basic load, and N is multiple sets of adjustment loads).

[0056] The main purpose of nitrogen production unit 1-210 is to produce nitrogen, which specifically includes a basic nitrogen production unit, a regulating nitrogen production unit and necessary nitrogen storage facilities; among them, the basic nitrogen production unit can adopt a cryogenic nitrogen production air separation (ASU) device or a large-scale pressure swing adsorption (PSA) nitrogen production unit. The ASU device separates nitrogen by liquefied air, while the PSA device produces nitrogen by adsorbing oxygen in the air. The basic nitrogen production unit is set to 1 set to meet the nitrogen demand under the basic load of the system. The regulating nitrogen production unit can adopt a PSA nitrogen production unit, the number of which is ≥ 0 sets. When the basic nitrogen production unit cannot meet the production demand, the regulating nitrogen production unit can be started to increase the nitrogen production. The nitrogen storage facilities are used to store the produced nitrogen, and specifically, high-pressure storage tanks or other types of storage containers can be used.

[0057] The electrolytic hydrogen production unit 1-220 produces hydrogen by electrolyzing water, and includes an electrolyzer, separation and purification equipment, and necessary hydrogen storage facilities, wherein the electrolyzer may be an alkaline electrolyzer (ALK), a proton exchange membrane electrolyzer (PEM), a high-temperature solid oxide electrolyzer (SOEC), or an anion exchange membrane electrolyzer (AEM), etc., with a quantity of ≥ 1 set. The separation and purification equipment is used to purify the hydrogen, and the hydrogen storage facilities are used to store the produced hydrogen.

[0058] It should be pointed out that the electrolytic cell, separation and purification equipment and hydrogen storage facilities in the electrolytic hydrogen production unit 1-220 are commonly used equipment for producing, separating and storing hydrogen in the existing hydrogen production process. The specific structure and working principle can refer to the existing technology and will not be repeated in the embodiments of the present invention.

[0059] The hydrogen and nitrogen compressor 1-230 includes a basic compressor, a regulating compressor and necessary interstage cooling / separation facilities. Among them, the basic compressor can be a centrifugal compressor or a large reciprocating compressor, the number is 1 set; the regulating compressor is a reciprocating compressor of the same specification, the number is ≥ 0 sets. The hydrogen and nitrogen ratio regulating unit is used to ensure that the mixing ratio (volume ratio or molar ratio) of hydrogen and nitrogen is a certain value, usually 3.

[0060] Ammonia synthesis tower 1-300 is a key equipment for synthesizing ammonia through catalytic reaction of nitrogen and hydrogen under high temperature and pressure. There are no special restrictions on the specific number of catalytic beds (two layers / three layers / four layers), fluid flow mode (axial / radial / axial radial), bed cooling method (cold shock type / intermediate heat exchange type) and the catalyst used, and any form of existing mature technology and its process combination can be used.

[0061] The outlet of the hydrogen-nitrogen module 1-20 is connected to the inlet of the ammonia synthesis tower 1-300 through the circulation machine 1-310. The circulation machine 1-310 can introduce hydrogen and nitrogen in a specific ratio into the ammonia synthesis tower 1-300 for chemical reaction; the outlet of the ammonia synthesis tower 1-300 is connected to the cooling and separation unit, and the gas product discharged through the outlet of the ammonia synthesis tower 1-300 enters the cooling and separation unit. The cooling and separation unit can cool the ammonia in the gas product into liquid ammonia and separate it, and the separated gas flows back to the ammonia synthesis tower 1-300 through the gas loop to continue to participate in the reaction.

[0062] In one embodiment of the present invention, the cooling and separation unit includes a water cooler 1-320, a primary ammonia separator 1-321, an ammonia cooler 1-322, and a secondary ammonia separator 1-323 connected in sequence; wherein the gas inlet of the water cooler 1-320 is connected to the outlet of the ammonia synthesis tower 1-300, and the gas outlet is connected to the inlet of the primary ammonia separator 1-321; the gas outlet of the primary ammonia separator 1-321 is connected to the inlet of the secondary ammonia separator 1-323 after passing through the ammonia cooler 1-322; the primary ammonia separator 1-321 and the secondary ammonia separator The liquid ammonia outlet of 1-323 is connected to the liquid ammonia storage tank after merging with the liquid ammonia main line 1-324, and is connected to the ammonia injection module 1-40 through the liquid ammonia branch line 1-326. The liquid ammonia main line 1-324 is connected with an XV4 valve 1-325, and the liquid ammonia branch line 1-326 is connected with an XV3 valve 1-327. In the flow direction of liquid ammonia, the XV4 valve 1-325 is located downstream of the connection point between the liquid ammonia branch line 1-326 and the liquid ammonia main line 1-324; the gas outlet of the secondary ammonia separator 1-323 is connected to the circulation machine 1-310 through the above-mentioned gas reflux.

[0063] In actual work, the gas product discharged from the outlet of the ammonia synthesis tower 1-300 is firstly cooled by the water cooler 1-320, and part of the ammonia gas is condensed into liquid, and then enters the primary ammonia separator 1-321 for gas-liquid separation. The liquid ammonia is discharged into the liquid ammonia main path 1-324 through the liquid ammonia outlet of the primary ammonia separator 1-321. The gas is cooled again by the ammonia cooler 1-322 and enters the secondary ammonia separator 1-323 for gas-liquid separation. The liquid ammonia is discharged into the liquid ammonia main path 1-324 through the liquid ammonia outlet of the secondary ammonia separator 1-323. The separated gas is refluxed to the ammonia synthesis tower 1-300 through the gas loop and the circulation machine 1-310 to continue to participate in the reaction.

[0064] Specifically, the water cooler 1-320 provides cooling capacity through a water cooling unit, and the water cooling unit is connected to the cooling water inlet / outlet of the water cooler 1-320 to provide cooling water for the water cooler 1-320. The ammonia cooling module 1-50 is used to provide cooling capacity for the ammonia cooler 1-322.

[0065] More specifically, the ammonia cooling module 1-50 includes a basic refrigeration device and a regulating refrigeration device; wherein the basic refrigeration device is an ammonia compression refrigeration cycle, the number of which is 1 set, and is used to meet the cooling demand of the ammonia cooler 1-322 under the system base load; the regulating refrigeration device is an ammonia compression refrigeration cycle or an ammonia absorption refrigeration cycle, the number of which is ≥ 0 sets. When the basic refrigeration device cannot meet the cooling demand, the regulating refrigeration device can be started to increase the cooling capacity.

[0066] In one embodiment of the present invention, the cooling and separation unit further includes a cold exchanger 1-328; the cold exchanger 1-328 is disposed between the primary ammonia separator 1-321 and the ammonia cooler 1-322; the gas outlet of the secondary ammonia separator 1-323 is connected to the cold exchanger 1-328 via a gas loop to provide a cold source for the cold exchanger 1-328.

[0067] In actual application, the gas separated by the primary ammonia separator 1-321 passes through the cold exchanger 1-328 and the ammonia cooler 1-322 in turn and then enters the secondary ammonia separator 1-323. The gas can reach a very low temperature after passing through the ammonia cooler 1-322, so the temperature of the gas discharged from the secondary ammonia separator 1-323 is very low. When this part of the low-temperature gas flows through the ammonia cooler 1-322, it can provide a cold source for the ammonia cooler 1-322 to cool the gas discharged from the primary ammonia separator 1-321, so as to fully utilize the cold capacity. The reflux after passing through the ammonia cooler 1-322 is introduced into the ammonia synthesis tower 1-300 through the circulation machine 1-310, and the temperature of the gas entering the ammonia synthesis tower 1-300 can be adjusted by the temperature control unit.

[0068] In order to facilitate the regulation of the temperature of the inlet gas entering the ammonia synthesis tower 1-300, the temperature control unit includes an electric heater 1-331; a heat exchanger is connected to the outlet of the ammonia synthesis tower 1-300, the hot flow inlet of the heat exchanger 1-330 is connected to the outlet of the ammonia synthesis tower 1-300, and the hot flow outlet is connected to the cooling separation unit; the cold flow inlet of the heat exchanger 1-330 is connected to the circulation machine 1-310, and the cold flow outlet is connected to the inlet of the electric heater 1-331 through the temperature control main path 1-332, and the outlet of the electric heater 1-331 is connected to the inlet of the ammonia synthesis tower 1-300.

[0069] Specifically, the synthesis of ammonia from hydrogen and nitrogen is an exothermic reaction under high temperature and pressure. Therefore, the gas product discharged from the outlet of the ammonia synthesis tower 1-300 has a very high temperature. After passing through the heat exchanger 1-330, the gas product can preheat the gas entering the ammonia synthesis tower 1-300. The gas preheated by the heat exchanger 1-330 flows through the electric heater 1-331 through the temperature control main path 1-332, and enters the ammonia synthesis tower 1-300 after being heated by the electric heater.

[0070] In order to further facilitate the control of the temperature of the inlet gas of the ammonia synthesis tower, the temperature control unit also includes a temperature control branch 1-333. The cold outlet of the heat exchanger 1-330 is directly connected to the inlet of the ammonia synthesis tower 1-300 through the temperature control branch 1-333. The TV3 valve 1-334 is connected to the temperature control main road 1-332, and the TV2 valve 1-335 is connected to the temperature control branch 1-333. In the flow direction of the gas, the TV3 valve 1-334 is located downstream of the connection point between the temperature control branch 1-333 and the temperature control main road 1-332. By controlling the ratio of the airflow flowing through the temperature control main road 1-332 and the temperature control branch 1-333, the gas temperature can be accurately controlled.

[0071] The temperature of the inlet gas of the ammonia synthesis tower 1-300 can be adjusted by the temperature control unit, and the ammonia content of the inlet gas of the ammonia synthesis tower 1-300 can be adjusted by the ammonia injection module 1-40. In one embodiment of the present invention, the ammonia injection module 1-40 includes an ammonia injection tank 1-410 and an ammonia injection pump 1-420; wherein the inlet of the ammonia injection tank 1-410 is connected to the liquid ammonia outlet of the cooling and separation unit, and the outlet is connected to the inlet of the ammonia synthesis tower 1-300 through the ammonia injection pump 1-420.

[0072] Specifically, the inlet of the ammonia spray tank 1-410 is connected to the liquid ammonia main line 1-324 through the liquid ammonia branch line 1-326. The liquid ammonia discharged from the liquid ammonia outlets of the primary ammonia separator 1-321 and the secondary ammonia separator 1-323 has two flow paths, one is flowing into the liquid ammonia storage tank through the liquid ammonia main line 1-324 for storage, and the other is flowing into the ammonia spray tank 1-410 through the liquid ammonia branch line 1-326; the ammonia spray tank 1-410 can buffer the liquid ammonia, the inlet of the ammonia spray pump 1-420 is connected to the ammonia spray tank 1-410, and the outlet is connected to the gas inlet of the ammonia synthesis tower 1-300 through the ammonia spray pipeline 1-430. The ammonia spray pipeline 1-430 is connected to the TV1 valve 1-440. The amount of ammonia sprayed can be controlled by controlling the opening of the TV1 valve 1-440, thereby regulating the ammonia content of the inlet gas of the ammonia synthesis tower 1-300.

[0073] In another embodiment of the present invention, the ammonia injection module 1-40 includes a liquid ammonia storage tank and an ammonia injection pump 1-420; wherein the inlet of the liquid ammonia storage tank is connected to the liquid ammonia outlet of the cooling and separation unit, and the outlet is connected to the inlet of the ammonia synthesis tower 1-300 through the ammonia injection pump 1-420. In this way, liquid ammonia can be directly extracted from the liquid ammonia storage tank during ammonia injection.

[0074] Specifically, a multi-point ammonia injection unit 1-301 is provided at the gas inlet of the ammonia synthesis tower 1-300, and the multi-point ammonia injection unit 1-301 is connected to the ammonia injection pipeline 1-430. Compared with single-point injection, multi-point injection can make liquid ammonia mix with the inlet gas of the ammonia synthesis tower 1-300 more quickly and evenly.

[0075] In order to make more effective use of the heat of synthetic ammonia, in one embodiment of the present invention, the production subsystem 1 also includes a waste heat power generation module; the waste heat power generation module includes a waste heat recovery unit 1-60 and a waste heat power generation unit 1-61; the waste heat recovery unit 1-60 is connected to the outlet of the ammonia synthesis tower 1-300, specifically located between the outlet of the ammonia synthesis tower 1-300 and the heat exchanger 1-330, and is used to recover waste heat in the gas product; the waste heat power generation unit 1-61 generates electricity using the waste heat recovered by the waste heat recovery unit 1-60.

[0076] Specifically, the waste heat recovery unit 1-60 may be a waste heat boiler or a multi-component molten salt heat storage unit.

[0077] In actual work, affected by the output of renewable energy power generation modules 1-10, when the production load is adjusted rapidly between (0~production load upper limit%), the circulating gas flow rate in the ammonia synthesis module 1-30 and the operating pressure of each equipment are maintained basically constant (△P≤20%Pdesign, that is, the pressure fluctuation range does not exceed 20% of the design pressure), thereby avoiding fatigue analysis and anti-fatigue design that may be required for each equipment in the ammonia synthesis module 1-30 under low production load conditions.

[0078] In a multi-stable synthetic ammonia preparation system at low production load, when the production load needs to be increased / decreased, the full production load (0~110%) can be adjusted by adjusting the hydrogen and nitrogen modules 1-20, the refrigeration module, the ammonia injection module 1-40 and the temperature control unit: The nitrogen production unit 1-210 in the hydrogen and nitrogen module 1-20 can start / stop and adjust the nitrogen production unit in sequence; the electrolytic hydrogen production unit 1-220 can start / stop the corresponding number of electrolysis equipment in sequence; the hydrogen and nitrogen compressor 1-230 can start / stop and adjust the compressor in sequence; the refrigeration module can start / stop the ammonia cooling module 1-50 in sequence. By controlling the opening of the TV1 valve 1-440 on the ammonia injection pipeline 1-430, the ammonia injection amount at the gas inlet of the ammonia synthesis tower 1-300 is adjusted in real time to increase / reduce the ammonia content of the inlet gas of the ammonia synthesis tower 1-300 By controlling the power of the electric heater 1-331 and the opening of the TV3 valve 1-334 on the temperature control main circuit 1-332, the inlet gas temperature of the ammonia synthesis tower 1-300 is increased / decreased. Thus, the inlet gas parameters of the ammonia synthesis tower 1-300 are adjusted, and then the ammonia synthesis module 1-30 is quickly adjusted within the full production load range.

[0079] In actual applications, when renewable energy has no output, the electrolytic hydrogen production unit 1-220 in the hydrogen-nitrogen module 1-20 stops running, resulting in the ammonia synthesis module 1-30 lacking sufficient raw gas and electricity required for normal operation. Therefore, it can only be shut down immediately. After the shutdown, the post-processing of the entire system (drainage, nitrogen filling and replacement, etc.) and the passivation operation of the catalyst are relatively cumbersome. What is more serious is that when renewable energy is output again, the hydrogen-nitrogen module 1-20 and the ammonia synthesis module 1-30 need to be restarted in sequence until normal production, which will last for several days and consume a lot of manpower, material and financial resources, and greatly affect the stability and reliability of the operation of the entire system.

[0080] In order to solve the above problems, in one embodiment of the present invention, the production subsystem 1 further includes an energy storage module 1-70 for storing renewable electricity. The energy storage module 1-70 can store the renewable electricity generated by the renewable energy generation module 1-10, thereby smoothing the volatility of the renewable electricity.

[0081] When the renewable energy power generation module 1-10 has no output for a short time (for example, hours), the electricity required by the production subsystem 1 can be provided by the energy storage module 1-70, or jointly provided by the energy storage module 1-70 and the waste heat power generation module. The ammonia synthesis module 1-30 maintains normal operation, and the hydrogen-nitrogen module 1-20 stops operating, resulting in a lack of sufficient raw gas required for normal operation in the ammonia synthesis module 1-30. Therefore, the synthetic ammonia unit is in a state of no hydrogen-nitrogen input and no liquid ammonia output, but the ammonia synthesis module 1-30 maintains normal circulation, and the circulation volume and the operating pressure of each equipment remain unchanged. Specifically, the liquid ammonia discharged from the liquid ammonia outlet of the cooling and separation unit is returned to the inlet of the ammonia synthesis tower 1-300 through the ammonia injection module 1-40, realizing a short-term hot standby function and avoiding the impact of frequent start and stop on the entire system.

[0082] Through the above technical scheme, short-term hot standby of the ammonia synthesis module 1-30 can be achieved, and when the renewable energy power generation module 1-10 has no output for a long time (daily level), in order to achieve long-term hot standby function, in one embodiment of the present invention, the production subsystem 1 also includes a public auxiliary module 1-80; the public auxiliary module (1-80) includes an emergency power generation unit, which is used to provide emergency power; the gas outlet of the first-level ammonia separator 1-321 is connected to the circulation machine 1-310 through the hot standby loop 1-336; the pipeline from the gas outlet of the first-level ammonia separator 1-321 to the ammonia cooler 1-322 is connected with an XV2 valve 1-337, and the hot standby loop 1-336 is connected with an XV1 valve 1-338.

[0083] Under short-term hot standby conditions, XV4 valve 1-325 and XV1 valve 1-338 are closed, XV3 valve 1-327 and XV2 valve 1-337 are opened, and the liquid ammonia discharged from the liquid ammonia outlet of the cooling separation unit is returned to the inlet of the ammonia synthesis tower 1-300 through the ammonia injection module 1-40, realizing the short-term hot standby function.

[0084] Under extreme working conditions, when the renewable energy power generation module 1-10 has no output for a long time (daily level), the hydrogen-nitrogen module 1-20 and the ammonia cooling module 1-50 are closed, the XV4 valve 1-325 and the XV2 valve 1-337 are disconnected, the XV3 valve 1-327 and the XV1 valve 1-338 are opened, and the circulating gas passes through the water cooler 1-320 and the first-stage ammonia separator 1-321 in turn and then directly returns to the inlet of the circulating machine 1-310. The liquid ammonia at the outlet of the first-stage ammonia separator 1-321 is all returned to the inlet of the ammonia synthesis tower 1-300 through the ammonia injection module 1-40, realizing a long-term hot standby function.

[0085] Under long-term hot standby conditions, the cold exchanger 1-328, the ammonia cooler 1-322, and the secondary ammonia separator 1-323 are in a shutdown state. During long-term hot standby, the power required by the circulation machine 1-310, the electric heater 1-331, and the ammonia injection pump 1-420 can be provided by the public auxiliary module 1-80, or can be provided jointly by the public auxiliary module 1-80 and the energy storage module 1-70 and / or the waste heat power generation module.

[0086] In one embodiment of the present invention, the production subsystem 1 further includes a data acquisition module for collecting operating parameters of each module in the production subsystem 1 .

[0087] Specifically, the data acquisition module may include a temperature monitoring unit, a pressure monitoring unit, a flow monitoring unit, a liquid level monitoring unit and a component monitoring unit, etc.; wherein the temperature monitoring unit is used to monitor the gas inlet / outlet temperature of the ammonia synthesis tower 1-300; the pressure monitoring unit is used to monitor the gas inlet pressure of the ammonia synthesis tower 1-300; the flow monitoring unit is used to monitor the flow of the hydrogen-nitrogen module 1-20 and the circulating gas flow (located in the gas outlet pipeline of the water cooler 1-320); the liquid level monitoring unit is used to monitor the liquid level of the ammonia spray tank 1-410; the component monitoring unit is used to monitor the ammonia content of the inlet gas of the ammonia synthesis tower 1-300.

[0088] For ease of control, refer to Figures 1 to 3The renewable energy multi-stable ammonia synthesis system also includes a control subsystem 2; the control subsystem 2 includes at least a basic process control module 2-10, other control modules 2-11 and a multi-stable scheduling module 2-12; the basic process control module 2-10 is pre-set with multi-level steady-state conditions corresponding to different production loads, and control parameters of each module in the production subsystem 1 under different steady-state conditions; other control modules 2-11 are used to predict the amount of renewable electricity at different time scales, and the amount of renewable electricity includes the power generation of renewable energy power generation modules 1-10 and The amount of electricity stored in the energy storage module 1-70; the multi-stable-state scheduling module 2-12 has built-in comprehensive power consumption corresponding to several steady-state conditions, and determines the adjustment direction according to the amount of renewable electricity and the comprehensive power consumption predicted by other control modules 2-11. When the difference is positive, the control parameters of the next-level steady-state condition in the basic process module 2-10 are called to adjust the current steady-state condition to the next-level steady-state condition. When the difference is negative, the control parameters of the previous-level steady-state condition in the basic process module 2-10 are called to adjust the current steady-state condition to the previous-level steady-state condition. When the difference is zero, the current steady-state condition is maintained.

[0089] Specifically, several typical steady-state working conditions are preset in the basic process control module 2-10, such as working condition 1, working condition 2, working condition 3... working condition N-2, working condition N-1, working condition N, and their production loads are 0, 10%, 20%... 90%, 100%, 110% respectively, and can also be set to other N consecutive or discontinuous integers that increase in sequence, where the working condition corresponding to the N-1 integer is 100% production load. Each working condition corresponds to a set of control parameters, which include but are not limited to the operating status of each device in the production subsystem 1, the opening of the valve, the set values ​​of the operating parameters (temperature, pressure, flow, liquid level, component) of each module, and the interlocking logic between multiple valves.

[0090] The other control modules 2-11 can predict the power generation of the renewable energy generation module 1-10 and the remaining power (SOC) of the energy storage module 1-70 at different time scales (minutes, hours, days, weeks) in the future, and send the renewable power to the multi-stable scheduling module 2-12.

[0091] The multi-stable dispatch module 2-12 has built-in comprehensive power consumption of each typical steady-state condition. The whole system power balance program (source + storage-load) calculates and solves the current steady-state condition (m condition) and takes corresponding adjustment measures according to source + storage-load: <0, it is judged that the power will be insufficient in the future and the production load should be reduced, so the m-1 working condition is called; =0, judging the future power balance, the production load should remain unchanged, and the current m working condition should be maintained; >0, it is judged that there will be excess electricity in the future and the production load should be increased, so the m+1 working condition is called.

[0092] The adjustment direction is determined according to the power and electricity balance program of the whole system, and the control parameters of the adjacent level steady-state conditions in the basic process control module 2-10 are directly called to adjust each module in the production subsystem 1 from the current m condition to the adjacent steady-state condition, thereby realizing continuous and stable production of multiple steady states and quasi-steady states.

[0093] Specifically, the basic process control module 2-10 is a DCS / SIS system; the other control modules 2-11 include functions such as wind / solar power prediction and energy storage remaining power SOC recording, which are usually integrated into the unified energy management system EMS of the whole plant; the multi-stable scheduling module 2-12 can be integrated into the EMS of the whole plant or set up separately.

[0094] It is to be understood that, without mutual contradiction, those skilled in the art may combine and combine the different embodiments or examples and the features of the different embodiments or examples described in this specification.

[0095] In one aspect, the present invention further provides a process for producing ammonia synthesized from renewable energy in multiple stable states, which is applicable to the system for synthesizing ammonia synthesized from renewable energy in multiple stable states provided in any of the above embodiments, and comprises the following steps: When the output of renewable energy power generation module 1-10 changes, maintain the outlet gas parameters (temperature, pressure, flow rate, ammonia content) of ammonia synthesis tower 1-300 ) remain unchanged, adjust the inlet gas parameters (temperature and ammonia content) of the ammonia synthesis tower 1-300 ), to change the degree to which the inlet gas of the ammonia synthesis tower 1-300 approaches the reaction equilibrium, thereby adjusting the net ammonia value at the inlet and outlet of the ammonia synthesis tower 1-300.

[0096] When the renewable energy power generation module 1-10 has no output for a short time, the hydrogen-nitrogen module 1-20 and the ammonia cooling module 1-50 are turned off, the XV-1 valve 1-336 is closed, the XV-2 valve 1-338 is opened, and the liquid ammonia at the outlets of the primary ammonia separator 1-321 and the secondary ammonia separator 1-323 are all returned to the inlet of the ammonia synthesis tower through the ammonia injection module 1-40, realizing the short-term hot standby function; the power required for short-term hot standby is jointly provided by the energy storage module 1-70 and the waste heat power generation module.

[0097] When the renewable energy power generation module 1-10 has no output for a long time, the hydrogen-nitrogen module 1-20 and the ammonia cooling module 1-50 are closed, the XV-1 valve 1-336 is opened, and the XV-1 valve 1-338 is closed. The circulating gas passes through the water cooler 1-320 and the first-stage ammonia separator 1-321 in turn and directly returns to the inlet of the circulation machine 1-310. The liquid ammonia at the outlet of the first-stage ammonia separator 1-321 is all returned to the inlet of the ammonia synthesis tower 1-300 through the ammonia injection module 1-40, realizing the long-term hot standby function; the cold exchanger 1-328, the ammonia cooling module 1-50, and the first-stage ammonia separator 1-323 are in a shutdown state; the electricity required for long-term hot standby is jointly provided by the emergency power generation unit of the public auxiliary module 1-80, the energy storage module 1-70 and the waste heat power generation module.

[0098] The control method of the renewable energy multi-stable ammonia synthesis system provided by the present invention is described below. The control method of the renewable energy multi-stable ammonia synthesis system described below and the control system of the renewable energy multi-stable ammonia synthesis system described above can be referred to each other.

[0099] Reference Figure 3 , a control method for a renewable energy multi-stable ammonia synthesis system, comprising the following steps: S100, dividing the multi-level steady-state working conditions step by step according to different production loads, and determining the control parameters of each module in the production subsystem 1 and the comprehensive power consumption of the production subsystem 1 under different levels of steady-state working conditions.

[0100] S101. Forecast the amount of renewable electricity at different time scales at preset time intervals. The amount of renewable electricity includes the amount of electricity generated by the renewable energy generation modules 1-10 and the amount of electricity stored in the energy storage modules 1-70.

[0101] S102: determining an adjustment direction according to the difference between the amount of renewable electricity and the corresponding comprehensive power consumption under the current steady-state working condition.

[0102] S104. When the difference is positive, adjust the current steady-state condition to the next steady-state condition; when the difference is negative, adjust the current steady-state condition to the previous steady-state condition; when the difference is zero, maintain the current steady-state condition.

[0103] Specifically, the control parameters of each module in the production subsystem 1 under different steady-state conditions and the comprehensive power consumption of the production subsystem 1 can be preset.

[0104] Figure 4 An example of a physical structure diagram of an electronic device is shown in FIG. Figure 4As shown, the electronic device may include: a processor 310 , a communications interface 320 , a memory 330 and a communication bus 340 , wherein the processor 310 , the communications interface 320 , and the memory 330 communicate with each other via the communication bus 340 . The processor 310 can call the logic instructions in the memory 330 to execute the control method of the renewable energy multi-stable ammonia synthesis system, which method includes: dividing the multi-level steady-state operating conditions step by step according to different production loads, and determining the control parameters of each module in the production subsystem 1 under different levels of steady-state operating conditions and the comprehensive power consumption of the production subsystem 1; predicting the amount of renewable electricity at different time scales at preset time intervals, and the amount of renewable electricity includes the power generation of renewable energy power generation modules 1-10 and the amount of electricity stored in the energy storage module 1-70; determining the adjustment direction according to the difference between the amount of renewable electricity and the corresponding comprehensive power consumption under the current steady-state operating condition; when the difference is positive, adjusting the current steady-state operating condition to the next level of steady-state operating condition, when the difference is negative, adjusting the current steady-state operating condition to the previous level of steady-state operating condition, and when the difference is zero, maintaining the current steady-state operating condition.

[0105] In addition, the logic instructions in the above-mentioned memory 330 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0106] On the other hand, the present invention also provides a computer program product, which includes a computer program, which can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the control method of the renewable energy multi-stable ammonia synthesis system provided by the above methods, the method including: dividing the multi-level steady-state operating conditions step by step according to different production loads, and determining the control parameters of each module in the production subsystem 1 under different levels of steady-state operating conditions and the comprehensive power consumption of the production subsystem 1; predicting the amount of renewable electricity at different time scales at preset time intervals, the amount of renewable electricity including the amount of electricity generated by the renewable energy power generation modules 1-10 and the amount of electricity stored in the energy storage modules 1-70; determining the adjustment direction according to the difference between the amount of renewable electricity and the corresponding comprehensive power consumption under the current steady-state operating condition; when the difference is positive, adjusting the current steady-state operating condition to the next level of steady-state operating condition, when the difference is negative, adjusting the current steady-state operating condition to the previous level of steady-state operating condition, and when the difference is zero, maintaining the current steady-state operating condition.

[0107] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to execute the control method of the renewable energy multi-stable ammonia synthesis system provided by the above-mentioned methods, the method comprising: dividing the multi-level steady-state operating conditions step by step according to different production loads, and determining the control parameters of each module in the production subsystem 1 under different levels of steady-state operating conditions and the comprehensive power consumption of the production subsystem 1; predicting the amount of renewable electricity at different time scales at preset time intervals, the amount of renewable electricity including the amount of electricity generated by the renewable energy power generation modules 1-10 and the amount of electricity stored in the energy storage modules 1-70; determining the adjustment direction according to the difference between the amount of renewable electricity and the corresponding comprehensive power consumption under the current steady-state operating condition; when the difference is positive, adjusting the current steady-state operating condition to the next level of steady-state operating condition, when the difference is negative, adjusting the current steady-state operating condition to the previous level of steady-state operating condition, and when the difference is zero, maintaining the current steady-state operating condition.

[0108] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0109] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0110] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A renewable energy multi-stable ammonia synthesis system, characterized in that: include: Production subsystem (1); The production subsystem (1) comprises: A renewable energy generation module (1-10) for generating renewable electricity; A hydrogen-nitrogen module (1-20) for preparing nitrogen and hydrogen required for synthesizing ammonia using the renewable electricity; An ammonia synthesis module (1-30) comprises an ammonia synthesis tower (1-300), a cooling and separation unit, a temperature adjustment unit and a circulation machine (1-310); the temperature adjustment unit is used to adjust the temperature of the inlet gas of the ammonia synthesis tower (1-300); the hydrogen-nitrogen module (1-20) is connected to the inlet of the ammonia synthesis tower (1-300) through the circulation machine (1-310); the inlet of the cooling and separation unit is connected to the outlet of the ammonia synthesis tower (1-300), and the gas outlet is connected to the inlet of the ammonia synthesis tower (1-300) through the gas loop and the circulation machine (1-310); An ammonia cooling module (1-50), used to provide cooling capacity for the cooling separation unit; The ammonia injection module (1-40) is used to adjust the ammonia content of the inlet gas of the ammonia synthesis tower (1-300).

2. The renewable energy multi-stable ammonia synthesis system according to claim 1, characterized in that: The production subsystem (1) further comprises an energy storage module (1-70) and a waste heat power generation module; The energy storage module (1-70) is used to store renewable electricity; The waste heat power generation module comprises a waste heat recovery unit (1-60) and a waste heat power generation unit (1-61); the waste heat recovery unit (1-60) is connected to the outlet of the ammonia synthesis tower (1-300) and is used to recover waste heat in the gas product; the waste heat power generation unit (1-61) generates electricity using the waste heat recovered by the waste heat recovery unit (1-60).

3. The renewable energy multi-stable ammonia synthesis system according to claim 2, characterized in that: The cooling and separation unit comprises a water cooler (1-320), a primary ammonia separator (1-321), an ammonia cooler (1-322) and a secondary ammonia separator (1-323) which are connected in sequence; The outlet of the ammonia synthesis tower (1-300) passes through the waste heat recovery unit (1-60) and the heat exchanger (1-330) in sequence and is connected to the inlet of the water cooler (1-320), and the outlet of the water cooler (1-320) is connected to the inlet of the primary ammonia separator (1-321); The gas outlet of the primary ammonia separator (1-321) is connected to the inlet of the secondary ammonia separator (1-323) through the ammonia cooler (1-322), and an XV-1 valve (1-336) is provided between the primary ammonia separator (1-321) and the ammonia cooler (1-322); The liquid ammonia outlets of the primary ammonia separator (1-321) and the secondary ammonia separator (1-323) are connected to the ammonia injection module (1-40) after being merged; The gas outlet of the secondary ammonia separator (1-323) is connected to the circulation machine (1-310) via the gas loop; The ammonia cooling module (1-40) is used to provide cooling capacity for the ammonia cooler (1-322).

4. The renewable energy multi-stable ammonia synthesis system according to claim 3, characterized in that: The production subsystem (1) further comprises a public auxiliary module (1-80); the public auxiliary module (1-80) comprises an emergency power generation unit; The gas outlet of the primary ammonia separator (1-321) is connected to the circulation machine (1-310) via a hot standby loop (1-336), and the hot standby loop (1-336) is connected to an XV-2 valve (1-338).

5. The renewable energy multi-stable ammonia synthesis system according to claim 3, characterized in that: The cooling separation unit also includes a cold exchanger (1-328) arranged between the primary ammonia separator (1-321) and the ammonia cooler (1-322), and the gas outlet of the secondary ammonia separator (1-323) is connected to the cold exchanger (1-328) to provide a cold source for the cold exchanger (1-328).

6. The renewable energy multi-stable ammonia synthesis system according to claim 3, characterized in that: The temperature adjustment unit comprises an electric heater (1-331); The heat flow inlet of the heat exchanger (1-330) is connected to the outlet of the ammonia synthesis tower (1-300), and the heat flow outlet is connected to the cooling and separation unit; The cold flow inlet of the heat exchanger (1-330) is connected to the circulation machine (1-310), and the cold flow outlet is connected to the electric heater (1-331) through the temperature control main line (1-332), and is connected to the inlet of the ammonia synthesis tower (1-300) through the temperature control branch line (1-333); the outlet of the electric heater (1-331) is connected to the inlet of the ammonia synthesis tower (1-300).

7. The renewable energy multi-stable ammonia synthesis system according to claim 1, characterized in that: A multi-point ammonia injection unit (1-301) is provided before the inlet of the ammonia synthesis tower (1-300); The ammonia spray module (1-40) comprises an ammonia spray tank (1-410) and an ammonia spray pump (1-420); the inlet of the ammonia spray tank (1-410) is connected to the liquid ammonia outlet of the cooling separation unit, and the outlet is connected to the multi-point ammonia spray unit (1-301) through the ammonia spray pump (1-420); Alternatively, the ammonia injection module (1-40) comprises a liquid ammonia storage tank and an ammonia injection pump (1-420); the inlet of the liquid ammonia storage tank is connected to the liquid ammonia outlet of the cooling separation unit, and the outlet is connected to the multi-point ammonia injection unit (1-301) through the ammonia injection pump (1-420).

8. The renewable energy multi-stable ammonia synthesis system according to claim 1, characterized in that: The hydrogen-nitrogen module (1-20) comprises a nitrogen production unit (1-210), an electrolytic hydrogen production unit (1-220), a hydrogen-nitrogen compressor (1-230) and a hydrogen-nitrogen ratio adjustment unit; The nitrogen production unit (1-210), the electrolytic hydrogen production unit (1-220) and the hydrogen-nitrogen compressor (1-230) all adopt a configuration of base load plus adjustment load.

9. The renewable energy multi-stable ammonia synthesis system according to claim 1, characterized in that: The ammonia cooling module (1-50) includes a basic refrigeration device and a regulating refrigeration device.

10. The renewable energy multi-stable ammonia synthesis system according to claim 1, characterized in that: The production subsystem (1) further comprises a data acquisition module, wherein the data acquisition module comprises: A temperature monitoring unit, used to monitor the gas inlet / outlet temperature of the ammonia synthesis tower (1-300); A pressure monitoring unit, used to monitor the gas inlet pressure of the ammonia synthesis tower (1-300); A flow monitoring unit, used to monitor the flow of the hydrogen and nitrogen modules (1-20) and the circulating gas flow; A liquid level monitoring unit, used for monitoring the liquid level of liquid ammonia in the ammonia injection module (1-40); The component monitoring unit is used to monitor the ammonia content of the inlet gas of the ammonia synthesis tower (1-300).

11. The renewable energy multi-stable ammonia synthesis system according to claim 10, characterized in that: Each valve in the production subsystem is interlocked and controlled with the data acquisition module.

12. The renewable energy multi-stable ammonia synthesis system according to any one of claims 1 to 11, characterized in that: It also includes a control subsystem (2); the control subsystem (2) includes: The basic process control module (2-10) is pre-set with multiple steady-state working conditions corresponding to different production loads, and control parameters of each module in the production subsystem (1) corresponding to different steady-state working conditions; Other control modules (2-11) are used to predict the amount of renewable electricity at different time scales, wherein the amount of renewable electricity includes the amount of electricity generated by the renewable energy generation module (1-10) and the amount of electricity stored by the energy storage module (1-70); The multi-stable scheduling module (2-12) has built-in comprehensive power consumption corresponding to several steady-state conditions, and determines the adjustment direction according to the amount of renewable electricity predicted by other control modules (2-11) and the comprehensive power consumption. When the difference is positive, the control parameters of the next-level steady-state condition in the basic process module (2-10) are called to adjust the current steady-state condition to the next-level steady-state condition. When the difference is negative, the control parameters of the previous-level steady-state condition in the basic process module (2-10) are called to adjust the current steady-state condition to the previous-level steady-state condition. When the difference is zero, the current steady-state condition is maintained.

13. A process for producing multi-stable ammonia synthesis from renewable energy, applicable to the multi-stable ammonia synthesis system from renewable energy as claimed in any one of claims 1 to 12, characterized in that: When the output of the renewable energy power generation module (1-10) changes, the outlet gas parameters (temperature, pressure, flow rate, ammonia content) of the ammonia synthesis tower (1-300) are maintained. ) remain unchanged, adjust the inlet gas parameters (temperature and ammonia content) of the ammonia synthesis tower (1-300) ), in order to change the degree to which the inlet gas of the ammonia synthesis tower (1-300) approaches the reaction equilibrium, thereby adjusting the net ammonia value at the inlet and outlet of the ammonia synthesis tower (1-300).

14. The process for producing multi-stable ammonia synthesis from renewable energy according to claim 13, characterized in that: When the renewable energy power generation module (1-10) has no output for a short period of time, the hydrogen nitrogen module (1-20) and the ammonia cooling module (1-50) are turned off, the XV-1 valve (1-336) is closed, the XV-2 valve (1-338) is opened, and the liquid ammonia at the outlets of the primary ammonia separator (1-321) and the secondary ammonia separator (1-323) are all returned to the inlet of the ammonia synthesis tower through the ammonia injection module (1-40), thereby realizing a short-term hot standby function; The power required for short-term hot standby is provided jointly by the energy storage module (1-70) and the waste heat power generation module.

15. The renewable energy multi-stable ammonia synthesis system according to claim 14, characterized in that: When the renewable energy power generation module (1-10) has no output for a long time, the hydrogen nitrogen module (1-20) and the ammonia cooling module (1-50) are closed, the XV-1 valve (1-336) is opened, and the XV-1 valve (1-338) is closed. The circulating gas passes through the water cooler (1-320) and the first-stage ammonia separator (1-321) in sequence and then directly returns to the inlet of the circulation machine (1-310). The liquid ammonia at the outlet of the first-stage ammonia separator (1-321) is all returned to the inlet of the ammonia synthesis tower (1-300) through the ammonia injection module (1-40), thereby realizing a long-term hot standby function; The cold exchanger (1-328), the ammonia cooling module (1-50), and the primary ammonia separator (1-323) are in shutdown state; The power required for long-term hot standby is jointly provided by the emergency power generation unit of the public auxiliary module (1-80), the energy storage module (1-70) and the waste heat power generation module.

16. A control method for a renewable energy multi-stable ammonia synthesis system, characterized in that: The following steps are involved: Dividing the multiple steady-state working conditions step by step according to different production loads, and determining the control parameters of each module in the production subsystem (1) and the comprehensive power consumption of the production subsystem (1) under different steady-state working conditions; At preset time intervals, the amount of renewable electricity at different time scales is predicted, wherein the amount of renewable electricity includes the amount of electricity generated by the renewable energy generation module (1-10) and the amount of electricity stored by the energy storage module (1-70); Determine the adjustment direction according to the difference between the amount of renewable electricity and the corresponding comprehensive power consumption under the current steady-state condition; When the difference is positive, the current steady-state operating condition is adjusted to the next level steady-state operating condition. When the difference is negative, the current steady-state operating condition is adjusted to the previous level steady-state operating condition. When the difference is zero, the current steady-state operating condition is maintained.

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