Hydrogen-ammonia-methanol co-production system based on renewable energy sources in sea area

Abstract

The hydrogen-ammonia-methanol co-production system based on the renewable energy sources in the sea area is integrated on an offshore energy island floating platform, seawater is desalted through a reverse osmosis device and then provides a water source for a proton exchange membrane electrolytic cell (200), and hydrogen and oxygen are prepared from water through an electrolytic reaction and are stored in storage tanks respectively; the nitrogen and carbon dioxide combined trapping system separates nitrogen and carbon dioxide in air through a compressor and an adsorption device, and the nitrogen and the carbon dioxide are respectively stored in a buffer tank; the ammonia synthesis system uses nitrogen in the nitrogen buffer tank and hydrogen in the hydrogen storage tank to synthesize ammonia in the ammonia synthesis reactor and store the ammonia; and the methanol synthesis system is used for reacting carbon dioxide in the carbon dioxide buffer tank with hydrogen through a methanol reactor to generate methanol and storing the methanol. According to the system, efficient negative carbon integrated co-production of marine renewable energy to hydrogen, ammonia and methanol is achieved, efficient utilization and conversion of marine renewable energy are achieved, and the system has important significance in promoting development and utilization of the marine renewable energy, carbon emission reduction and flexible energy supply.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sea renewable energy conversion and utilization, in particular to a hydrogen-ammonia-methanol co-production system based on sea renewable energy. BACKGROUND

[0002] The offshore energy island is an offshore facility platform integrating energy processing and conversion, storage and deployment functions, which will gradually become an offshore energy supply hub in the future. The sea renewable energy hydrogen production technology based on the offshore energy island is a solution that can effectively solve the problems of deep sea power grid connection and high transportation cost. However, the large-scale hydrogen storage technology has hindered the development of this technology. Ammonia is not only a widely used chemical product, but also a high-quality hydrogen storage medium with mild storage and transportation conditions and high energy density. In addition, methanol, as an energy with high market demand and safe storage and transportation at room temperature, is also a highly potential hydrogen storage medium.

[0003] Currently, there are related patents for offshore renewable energy hydrogen production systems, green ammonia synthesis systems of renewable energy, and green methanol production systems of renewable energy. However, there is no related technology for the co-production of hydrogen, ammonia and methanol based on offshore renewable energy. Therefore, it is urgent to develop a hydrogen-ammonia-methanol co-production method and system based on offshore energy islands, which can not only realize the efficient co-production of hydrogen, ammonia and methanol, but also reduce the cost of methanol synthesis and meet the compactness requirements of equipment, and can supply energy to offshore users. SUMMARY

[0004] Therefore, the present application discloses a hydrogen-ammonia-methanol co-production system based on sea renewable energy, and the specific scheme is as follows: The hydrogen-ammonia-methanol co-production system based on sea renewable energy includes an offshore energy island floating platform and a seawater desalination system, an electrolytic water hydrogen production system, a nitrogen and carbon dioxide joint capture system, an ammonia synthesis system and a methanol synthesis system arranged on the offshore energy island floating platform; The seawater desalination system includes a reverse osmosis seawater desalination device for desalinating seawater; The electrolytic water hydrogen production system includes a proton exchange membrane electrolytic cell, an oxygen storage tank and a hydrogen storage tank. The proton exchange membrane electrolytic cell is communicated with the reverse osmosis seawater desalination device through a pipeline, and the oxygen storage tank and the hydrogen storage tank are respectively communicated with the proton exchange membrane electrolytic cell through a pipeline; The nitrogen-carbon dioxide combined capture system comprises a third compressor, a nitrogen and carbon dioxide capture device, a carbon dioxide buffer tank and a nitrogen buffer tank, the nitrogen and carbon dioxide capture device comprises a nitrogen adsorption mechanism and a carbon dioxide adsorption mechanism, the first compressor is connected with the nitrogen adsorption mechanism, the nitrogen adsorption mechanism is communicated with the nitrogen buffer tank through a pipeline, the gas outlet of the nitrogen adsorption mechanism is communicated with the gas inlet of the carbon dioxide adsorption mechanism, and the carbon dioxide adsorption mechanism is communicated with the carbon dioxide buffer tank through a pipeline. The ammonia synthesis system comprises a first ammonia synthesis reactor and an ammonia storage tank, the first ammonia synthesis reactor is communicated with the nitrogen buffer tank and the hydrogen storage tank respectively, and the first ammonia synthesis reactor is communicated with the ammonia storage tank through a pipeline. The methanol synthesis system comprises a methanol synthesis reactor and a methanol storage tank, the methanol synthesis reactor is communicated with the carbon dioxide buffer tank and the hydrogen storage tank respectively, and the methanol synthesis reactor is communicated with the methanol storage tank through a pipeline.

[0005] As a supplement to the technical scheme of the present application, the power generation system is arranged on the offshore energy island floating platform, the power generation system comprises a power generation device, a proton exchange membrane fuel cell stack and a storage battery, the power generation device is connected with each electrical equipment in the seawater desalination system, the water electrolysis hydrogen production system, the nitrogen-carbon dioxide combined capture system, the ammonia synthesis system and the methanol synthesis system. The proton exchange membrane fuel cell stack is communicated with the hydrogen storage tank, the hydrogen storage tank serves as a hydrogen source, and the hydrogen and the external air are transported into the fuel cell stack to generate electricity; the power generation device and the proton exchange membrane fuel cell stack are connected with the storage battery, and the storage battery stores electrical energy.

[0006] As a supplement to the technical scheme of the present application, the water electrolysis hydrogen production system further comprises an anode gas-water separator, a cathode gas-water separator, an oxygen remover, a dryer and a first compressor. The oxygen storage tank and the proton exchange membrane electrolytic cell are provided with the anode gas-water separator. The hydrogen storage tank and the proton exchange membrane electrolytic cell are provided with the cathode gas-water separator, the oxygen remover, the dryer and the first compressor in sequence along the hydrogen conveying direction.

[0007] As a supplement to the technical scheme of the present application, the hydrogen conveying system is further provided, the ammonia synthesis system further comprises a fourth compressor, a nitrogen conveying pipeline and a third electric valve, the first ammonia synthesis reactor is communicated with the nitrogen buffer tank through the nitrogen conveying pipeline, the fourth compressor is arranged on the nitrogen conveying pipeline, the third electric valve is arranged on the nitrogen conveying pipeline between the nitrogen buffer tank and the fourth compressor, the hydrogen storage tank of the water electrolysis hydrogen production system is communicated with the nitrogen conveying pipeline through the hydrogen conveying system, so that the hydrogen is conveyed into the first ammonia synthesis reactor through the nitrogen conveying pipeline, and the first ammonia synthesis reactor is communicated with the ammonia storage tank. The methanol synthesis system further comprises a fifth compressor, a carbon dioxide conveying pipeline, and a fourth electric valve; the carbon dioxide buffer tank is communicated with the methanol synthesis reactor through the carbon dioxide conveying pipeline, the fifth compressor is arranged on the carbon dioxide conveying pipeline, the hydrogen storage tank of the electrolytic water hydrogen production system is communicated with the carbon dioxide conveying pipeline through a hydrogen conveying system, so that hydrogen and carbon dioxide are conveyed into the methanol synthesis reactor through the carbon dioxide conveying pipeline to react to generate methanol, and the methanol synthesis reactor is communicated with a methanol storage tank.

[0008] As a supplement to the technical scheme of the present application, the hydrogen conveying system comprises a second compressor, a hydrogen conveying main pipeline, a first hydrogen conveying branch pipeline, a second hydrogen conveying branch pipeline, a first electric valve, and a second electric valve; the second compressor is communicated with the hydrogen storage tank through the hydrogen conveying main pipeline, one end of the first hydrogen conveying branch pipeline is communicated with the second compressor, the other end is communicated with the carbon dioxide conveying pipeline, and the first electric valve is arranged on the first hydrogen conveying branch pipeline; one end of the second hydrogen conveying branch pipeline is communicated with the second compressor, the other end is communicated with the nitrogen conveying pipeline, and the second electric valve is arranged on the second hydrogen conveying branch pipeline.

[0009] As a supplement to the technical scheme of the present application, the ammonia synthesis system further comprises a first heat exchanger, a second ammonia synthesis reactor, and an ammonia separator; the first heat exchanger is arranged between the first ammonia synthesis reactor and the second ammonia synthesis reactor, the second ammonia synthesis reactor is communicated with the ammonia separator, and the ammonia separator is communicated with the first ammonia synthesis reactor and an ammonia storage tank respectively.

[0010] As a supplement to the technical scheme of the present application, the methanol synthesis system further comprises a sixth compressor, a methanol separator, a second heat exchanger, a permeation evaporation membrane unit, and a reflux pipeline. The methanol synthesis reactor is communicated with the methanol separator, the methanol separator is communicated with the carbon dioxide conveying pipeline through the reflux pipeline, the sixth compressor is arranged on the carbon dioxide conveying pipeline, the methanol separator is communicated with the methanol storage tank through a methanol conveying pipeline, and the methanol conveying pipeline is provided with a second heat exchanger and a permeation membrane evaporation unit.

[0011] As a supplement to the technical scheme of the present application, a heat control system is further included, which comprises a seawater heat exchange pipeline; the seawater heat exchange pipeline is sequentially communicated with a proton exchange membrane electrolytic cell, a first heat exchanger, a second heat exchanger, and a nitrogen and carbon dioxide capturing device, so as to form a closed circulation cooling loop.

[0012] As a supplement to the technical scheme of the present application, the nitrogen and carbon dioxide capturing device comprises a first capturing reactor, a second capturing reactor, a metal isolation layer, a first gas conveying pipeline, a second gas conveying pipeline, a third gas conveying pipeline, a fourth gas conveying pipeline, a first gas discharge pipeline, a second gas discharge pipeline, a first stop valve, a second stop valve, a third stop valve, a fourth stop valve, a fifth stop valve, and a sixth stop valve. The first capturing reactor comprises a first nitrogen adsorption bed and a first carbon dioxide adsorption bed arranged adjacently, and the second capturing reactor comprises a second nitrogen adsorption bed and a second carbon dioxide adsorption bed arranged adjacently; each adsorption bed of the first capturing reactor and the second capturing reactor is coated with a metal isolation layer on the outside for isolating gas, and each adsorption bed is provided with a gas inlet and a gas outlet, and the metal isolation layer at the positions of the gas inlets and the gas outlets of the adsorption beds is provided with through holes. The gas inlets of the first nitrogen adsorption bed and the second nitrogen adsorption bed are connected with the third compressor through pipelines. The gas outlet of the first nitrogen adsorption bed is connected in communication with the gas inlet of the second carbon dioxide adsorption bed through a pipeline, the first nitrogen adsorption bed is connected in communication with a nitrogen buffer tank through a first gas conveying pipeline, the first stop valve is arranged on the first gas conveying pipeline, the second nitrogen adsorption bed is connected in communication with the nitrogen buffer tank through a second gas conveying pipeline, the second stop valve is arranged on the second gas conveying pipeline, the first carbon dioxide adsorption bed is connected in communication with a carbon dioxide buffer tank through a third gas conveying pipeline, the third stop valve is arranged on the third gas conveying pipeline, and the second carbon dioxide adsorption bed is connected in communication with the carbon dioxide buffer tank through a fourth gas conveying pipeline, and the fourth stop valve is arranged on the third gas conveying pipeline. The gas outlet of the first nitrogen adsorption bed is connected in communication with the gas inlet of the second carbon dioxide adsorption bed through a pipeline, the gas outlet of the second carbon dioxide adsorption bed is connected with a first gas discharge pipeline, and the fifth stop valve is arranged on the first gas discharge pipeline. The gas outlet of the second nitrogen adsorption bed is connected in communication with the gas inlet of the first carbon dioxide adsorption bed through a pipeline, the gas outlet of the first carbon dioxide adsorption bed is connected with a second gas discharge pipeline, and the sixth stop valve is arranged on the first gas discharge pipeline.

[0013] The material of the nitrogen adsorption bed is metal organic framework MOF-801, which generates heat when adsorbing nitrogen.

[0014] The material of the carbon dioxide adsorption bed is K2CO3 / ZrO2 solid adsorbent, which generates heat when adsorbing carbon dioxide. The nitrogen adsorption mechanism is a nitrogen adsorption bed, and the carbon dioxide adsorption mechanism is a carbon dioxide adsorption bed.

[0015] As a supplement to the technical scheme of the present application, the first trapping reactor and the second trapping reactor are structurally identical, each comprising a cylindrical core bed and an odd number of tubular beds; each tubular bed is in a concentrically sleeved relationship, the tubular bed on the outside is sleeved outside the inner bed, the materials of adjacent two beds are different, and metal isolation plates are arranged between adjacent two beds and on the outer surface of the outermost tubular bed.

[0016] Beneficial effects: The hydrogen-ammonia-methanol co-production system based on marine renewable energy disclosed in the present application has the following advantages: The hydrogen-ammonia-methanol co-production method and system based on the offshore energy island can realize the co-production of hydrogen, ammonia and methanol by using marine renewable energy, and can provide power for offshore floating oil and gas drilling platforms and oxygen for marine ranches. Ammonia and methanol can be directly transported by ships, reducing the cost and loss of land transportation, and being especially suitable for hydrogen energy sea transportation scenarios.

[0017] In another aspect of the present application, the energy consumption of carbon dioxide capture is significantly reduced. The nitrogen and carbon dioxide capture system increases the carbon dioxide concentration in the denitrogenated air from 0.041% to 0.187% by first adsorbing nitrogen, greatly reducing the energy consumption and cost of carbon dioxide capture, avoiding the high cost bottleneck of direct air capture, and laying a foundation for the commercialization of methanol synthesis. The nitrogen and carbon dioxide capture device adopts a modular concentric tubular bed structure, and realizes gas isolation through a metal isolation layer. In a limited space, the nitrogen and carbon dioxide capture functions are integrated to meet the compactness requirement of the offshore energy island floating platform. The nitrogen and carbon dioxide capture device couples the heat energy of bed adsorption heat release and desorption heat absorption, uses the heat generated during the adsorption process to drive desorption, and reduces external energy input. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The figure is a structural schematic diagram of the hydrogen-ammonia-methanol co-production system of the present application.

[0019] Figure 2 The figure is a structural schematic diagram of the hydrogen-ammonia-methanol co-production system of the present application.

[0020] Figure 3 The figure is a structural schematic diagram of the nitrogen and carbon dioxide capture device of the present application.

[0021] Figure 4 The figure is a structural schematic diagram of the first carbon capture device of the present application.

[0022] Figure 5 The figure is a sectional structural schematic diagram of the first carbon capture device of the present application.

[0023] Figure 6 The figure is a working principle schematic diagram of the first carbon capture device and the second carbon capture device of the present application.

[0024] Figure 7 Fig. 1 is a schematic diagram of the working principle of the first carbon capture device of the present application. In the figure: 100. water pump, 101. reverse osmosis seawater desalination device; 200. proton exchange membrane electrolyzer, 201. oxygen storage tank, 202. hydrogen storage tank, 203. anode gas water separator, 204. cathode gas water separator, 205. oxygen remover, 206. dryer, 207. first compressor; 300. third compressor, 301. nitrogen and carbon dioxide capture device, 302. carbon dioxide buffer tank, 303. nitrogen buffer tank, 304. first capture reactor, 305. second capture reactor, 306. metal isolation layer, 307. first gas delivery pipeline, 308. second gas delivery pipeline, 309. third gas delivery pipeline, 310. fourth gas delivery pipeline, 311. first gas discharge pipeline, 312. second gas discharge pipeline, 313. first shut-off valve, 314. second shut-off valve, 315. third shut-off valve, 316. fourth shut-off valve, 317. fifth shut-off valve, 318. sixth shut-off valve, 319. first nitrogen adsorption bed, 320. first carbon dioxide adsorption bed, 321. second nitrogen adsorption bed, 322. second carbon dioxide adsorption bed, 323. core bed, 324. first layer tubular bed, 325. second layer tubular bed, 326. third layer tubular bed; 400. first ammonia synthesis reactor, 401. ammonia storage tank, 402. fourth compressor, 403. nitrogen delivery pipeline, 404. third electric valve, 405. first heat exchanger, 406. second ammonia synthesis reactor, 407. ammonia separator; 500. methanol synthesis reactor, 501. methanol storage tank, 502. fifth compressor, 503. carbon dioxide delivery pipeline, 504. sixth compressor, 505. methanol separator, 506. second heat exchanger, 507. pervaporation membrane unit, 508. reflux pipeline, 509. fourth electric valve; 600. power generation device, 601. proton exchange membrane fuel cell stack, 602. battery; 700. second compressor, 701. hydrogen delivery main pipeline, 702. first hydrogen delivery branch pipeline, 703. second hydrogen delivery branch pipeline, 704. first electric valve, 705. second electric valve; 800. seawater heat exchange pipeline, 900. marine ranch, 1000. oil and gas drilling platform. DETAILED DESCRIPTION

[0025] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0026] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0027] like Figure 1 , Figure 2 As shown, the hydrogen-ammonia-methanol cogeneration system based on marine renewable energy includes a floating platform for offshore energy islands and a seawater desalination system, a water electrolysis hydrogen production system, a nitrogen and carbon dioxide co-capture system, an ammonia synthesis system, a methanol synthesis system, and a hydrogen transportation system installed on the floating platform for offshore energy islands.

[0028] The seawater desalination system includes a water pump 100 and a reverse osmosis seawater desalination unit 101. The water pump 100 draws seawater and transports it through pipelines to the reverse osmosis seawater desalination unit 101, where the salt and impurities in the seawater are removed by reverse osmosis membrane separation technology to produce freshwater that meets the standards.

[0029] The water electrolysis hydrogen production system includes a proton exchange membrane electrolyzer 200, an oxygen storage tank 201, and a hydrogen storage tank 202. A reverse osmosis seawater desalination unit 101 is connected to the proton exchange membrane electrolyzer 200 via pipelines to deliver fresh water into the electrolyzer 200, where oxygen and hydrogen are produced through water electrolysis. The oxygen storage tank 201 and hydrogen storage tank 202 are respectively connected to the proton exchange membrane electrolyzer 200 via pipelines to collect and store the oxygen and hydrogen generated by the electrolysis. The oxygen stored in the oxygen storage tank 201 can be transported to the marine ranch 900.

[0030] The nitrogen and carbon dioxide combined capture system comprises a third compressor 300, a nitrogen and carbon dioxide capture device 301, a carbon dioxide buffer tank 302 and a nitrogen buffer tank 303.

[0031] The carbon dioxide concentration in air is about 0.041%, which leads to high cost of the carbon dioxide capture process, and further leads to high cost of methanol leveling, which hinders large-scale commercial application. The carbon dioxide concentration in denitrogenated air is about 0.187%, which is about 4.6 times higher than that in air, greatly reducing the energy consumption and cost of the carbon dioxide capture process. The carbon dioxide adsorption mechanism is connected with the carbon dioxide buffer tank 302 through a pipeline, and is used for conveying the adsorbed carbon dioxide into the nitrogen buffer tank 303.

[0032] The ammonia synthesis system comprises a first ammonia synthesis reactor 400 and an ammonia storage tank 401. The methanol synthesis system comprises a methanol synthesis reactor 500 and a methanol storage tank 501.

[0033] Through the above setting, the hydrogen, ammonia and methanol can be co-produced by using the renewable energy in the sea area, the carbon dioxide is captured by using the denitrogenated air after the nitrogen capture, instead of directly capturing the carbon dioxide by using air, which greatly reduces the energy consumption and cost of the carbon dioxide capture process, and further significantly reduces the energy loss of the whole system.

[0034] As a supplement to the technical scheme of the present application, a power generation system is arranged on the offshore energy island floating platform, and the power generation system comprises a power generation device 600 connected with each electrical equipment in the seawater desalination system, the hydrogen production system by electrolysis of water, the nitrogen and carbon dioxide combined capture system, the ammonia synthesis system, the methanol synthesis system and the hydrogen delivery system, and is used for supplying electric energy to the electrical equipment.

[0035] As a supplement to the above technical scheme, the power generation system further comprises a proton exchange membrane fuel cell stack 601 and a storage battery 602, the proton exchange membrane fuel cell stack 601 is communicated with the hydrogen storage tank 202, the hydrogen storage tank 202 serves as a hydrogen source, and hydrogen is transported into the fuel cell stack together with ambient air to realize a power generation function. The power generation device 600 and the proton exchange membrane fuel cell stack 601 are connected with the storage battery 602, and the storage battery 602 is used for storing electric energy. Excess electric energy can be transported to the offshore oil and gas drilling platform 1000 to meet the power demand thereof.

[0036] As a preferred technical scheme of the present application, a hydrogen delivery system is further included, and the ammonia synthesis system further comprises a fourth compressor 402, a nitrogen delivery pipeline 403 and a third electric valve 404. The first ammonia synthesis reactor 400 is communicated with the nitrogen buffer tank 303 through the nitrogen delivery pipeline 403, the fourth compressor 402 is arranged on the nitrogen delivery pipeline 403, and the third electric valve 404 is arranged on the nitrogen delivery pipeline 403 between the nitrogen buffer tank 303 and the fourth compressor 402. The fourth compressor 402 is used for delivering nitrogen into the first ammonia synthesis reactor 400, the hydrogen storage tank 202 of the water electrolysis hydrogen production system is communicated with the nitrogen delivery pipeline 403 through the hydrogen delivery system, so that hydrogen is delivered into the first ammonia synthesis reactor 400 through the nitrogen delivery pipeline 403, and nitrogen and hydrogen in the first ammonia synthesis reactor 400 react to generate ammonia. The first ammonia synthesis reactor 400 is communicated with the ammonia storage tank 401, and the ammonia storage tank 401 is used for storing ammonia.

[0037] Preferably, the methanol synthesis system further comprises a fifth compressor 502, a carbon dioxide delivery pipeline 503 and a fourth electric valve 509. The carbon dioxide buffer tank 302 is communicated with the methanol synthesis reactor 500 through the carbon dioxide delivery pipeline 503, the fifth compressor 502 is arranged on the carbon dioxide delivery pipeline 503, and the fourth electric valve 509 is arranged on the carbon dioxide delivery pipeline 503 between the fifth compressor 502 and the carbon dioxide buffer tank 302, and is used for delivering carbon dioxide in the carbon dioxide buffer tank 302 into the methanol synthesis reactor 500. The hydrogen storage tank 202 of the water electrolysis hydrogen production system is communicated with the carbon dioxide delivery pipeline 503 through the hydrogen delivery system, so that hydrogen and carbon dioxide are delivered into the methanol synthesis reactor 500 through the carbon dioxide delivery pipeline 503 to react to generate methanol. The methanol synthesis reactor 500 is communicated with the methanol storage tank 501, and the methanol storage tank 501 is used for storing methanol.

[0038] The hydrogen delivery system comprises a second compressor 700, a hydrogen delivery main pipeline 701, a first hydrogen delivery branch pipeline 702, a second hydrogen delivery branch pipeline 703, a first electric valve 704, and a second electric valve 705. The second compressor 700 is communicated with the hydrogen storage tank 202 through the hydrogen delivery main pipeline 701. One end of the first hydrogen delivery branch pipeline 702 is communicated with the second compressor 700, and the other end is communicated with the carbon dioxide delivery pipeline 503. The first electric valve 704 is arranged on the first hydrogen delivery branch pipeline 702 and controls the opening and closing of the first hydrogen delivery branch pipeline 702. One end of the second hydrogen delivery branch pipeline 703 is communicated with the second compressor 700, and the other end is communicated with the nitrogen delivery pipeline 403. The second electric valve 705 is arranged on the second hydrogen delivery branch pipeline 703 and controls the opening and closing of the second hydrogen delivery branch pipeline 703.

[0039] As a preferred technical scheme of the present application, the ammonia synthesis system further comprises a first heat exchanger 405, a second ammonia synthesis reactor 406, and an ammonia separator 407. The first heat exchanger 405 is arranged between the first ammonia synthesis reactor 400 and the second ammonia synthesis reactor 406. The second ammonia synthesis reactor 406 is communicated with the ammonia separator 407. The ammonia separator 407 is communicated with the first ammonia synthesis reactor 400 and the ammonia storage tank 401 respectively.

[0040] The first heat exchanger 405 utilizes the waste heat of the high-temperature synthesis gas at the outlet of the first ammonia synthesis reactor 400 to preheat the gas entering the second ammonia synthesis reactor 406, thereby reducing the energy consumption of the system and providing suitable initial temperature conditions for the catalytic reaction in the second ammonia synthesis reactor 406, which guarantees the efficient reaction.

[0041] The first ammonia synthesis reactor 400 is used for further reaction of the completely reacted gas in the second ammonia synthesis reactor 406, and then the gas is introduced into the ammonia separator 407. The ammonia separator 407 separates the generated liquid ammonia from the unreacted gaseous raw materials by condensation, compression or other separation technologies. The separated liquid ammonia is delivered to the ammonia storage tank 401 for storage. The unreacted nitrogen, hydrogen and other raw material gases are sent back to the first ammonia synthesis reactor 400, realizing the recycling of raw materials and greatly improving the economy and raw material utilization rate of the entire ammonia synthesis system.

[0042] As a preferred technical scheme of the present application, the methanol synthesis system further comprises a sixth compressor 504, a methanol separator 505, a second heat exchanger 506, a pervaporation membrane unit 507, and a reflux pipeline 508.

[0043] The methanol synthesis reactor 500 is communicated with a methanol separator 505, the methanol separator 505 is communicated with a carbon dioxide conveying pipeline 503 through a reflux pipeline 508, a sixth compressor 504 is arranged on the carbon dioxide conveying pipeline 503, the methanol separator 505 is communicated with a methanol storage tank 501 through a methanol conveying pipeline, and the methanol conveying pipeline is provided with a second heat exchanger 506 and a permeation membrane evaporation unit.

[0044] The gas-liquid mixture at the outlet of the methanol synthesis reactor 500 firstly enters the methanol separator 505 for preliminary separation, the unreacted gas after separation is connected to the carbon dioxide conveying pipeline 503 through the reflux pipeline 508, the sixth compressor 504 is arranged on the conveying pipeline, and is used for pressurizing the circulating gas and sending it back to the reaction system; the separated crude methanol enters the methanol storage tank 501 through the methanol conveying pipeline in turn and passes through the second heat exchanger 506 and the permeation membrane evaporation unit. The second heat exchanger 506 and the permeation membrane evaporation unit on the methanol conveying pipeline constitute a refining treatment unit of crude methanol, and realize the dual functions of heat recovery and product purification. The second heat exchanger 506 is used for reducing the temperature of the crude methanol before being conveyed to the permeation membrane evaporation unit through a heat exchange medium such as circulating water or a coolant, so as to provide suitable feeding conditions for the subsequent membrane separation process and avoid damage to the membrane material caused by high temperature, and meanwhile realize the cyclic utilization of energy.

[0045] Since the offshore energy island floating platform has high requirements on compact space, the traditional nitrogen capture system and carbon dioxide capture system suitable for land are directly connected to realize the joint adsorption system equipment, which is difficult to meet the requirements of compactness. Figures 3 to 7 As shown in the figure, as the preferred technical solution of the present application, the nitrogen and carbon dioxide capture device 301 comprises a first capture reactor 304, a second capture reactor 305, a metal isolation layer 306, a first gas conveying pipeline 307, a second gas conveying pipeline 308, a third gas conveying pipeline 309, a fourth gas conveying pipeline 310, a first gas discharge pipeline 311, a second gas discharge pipeline 312, a first stop valve 313, a second stop valve 314, a third stop valve 315, a fourth stop valve 316, a fifth stop valve 317, a sixth stop valve 318, the first capture reactor 304 comprises a first nitrogen adsorption bed layer 319 and a first carbon dioxide adsorption bed layer 320 arranged adjacently, and the second capture reactor 305 comprises a second nitrogen adsorption bed layer 321 and a second carbon dioxide adsorption bed layer 322 arranged adjacently.

[0046] The adsorption bed layers of the first capture reactor 304 and the second capture reactor 305 are both coated with the metal isolation layer 306 for isolating gas.

[0047] Each adsorption bed is provided with an air inlet and an air outlet, the metal isolation layer 306 at the air inlet and the air outlet of the adsorption bed is provided with a through hole, so that the pipeline can pass through the through hole of the metal isolation layer 306 and communicate with the air inlet and the air outlet of the adsorption bed.

[0048] The air inlets of the first nitrogen adsorption bed 319 and the second nitrogen adsorption bed 321 are connected with the third compressor 300 through pipelines, and a stop valve is arranged on the pipeline communicating with the third compressor 300.

[0049] The air outlet of the first nitrogen adsorption bed 319 is communicated with the air inlet of the second carbon dioxide adsorption bed 322 through a pipeline, the first nitrogen adsorption bed 319 is communicated with the nitrogen buffer tank 303 through a first gas conveying pipeline 307, a first stop valve 313 is arranged on the first gas conveying pipeline 307, the second nitrogen adsorption bed 321 is communicated with the nitrogen buffer tank 303 through a second gas conveying pipeline 308, and a second stop valve 314 is arranged on the second gas conveying pipeline 308.

[0050] The first carbon dioxide adsorption bed 320 is communicated with the carbon dioxide buffer tank 302 through a third gas conveying pipeline 309, and a third stop valve 315 is arranged on the third gas conveying pipeline 309. The second carbon dioxide adsorption bed 322 is communicated with the carbon dioxide buffer tank 302 through a fourth gas conveying pipeline 310, and a fourth stop valve 316 is arranged on the third gas conveying pipeline 309.

[0051] The air outlet of the second carbon dioxide adsorption bed 322 is connected with a first gas discharge pipeline 311, and the first gas discharge pipeline 311 is provided with a fifth stop valve 317. The air outlet of the first carbon dioxide adsorption bed 320 is connected with a second gas discharge pipeline 312, and the first gas discharge pipeline 311 is provided with a sixth stop valve 318.

[0052] The "air inlet" and the "air outlet" on each bed are through holes opened on the metal isolation layer 306, so that the pipeline can communicate with the bed.

[0053] The material of the nitrogen adsorption bed is metal organic framework MOF-801, which generates heat when adsorbing nitrogen.

[0054] The material of the carbon dioxide adsorption bed is K2CO3 / ZrO2 solid adsorbent, which generates heat when adsorbing carbon dioxide.

[0055] The nitrogen and carbon dioxide capturing device 301 needs to be filled with nitrogen and carbon dioxide before use. The treatment steps are as follows: first, air is sent to the first nitrogen adsorption bed 319 in the first capturing reactor 304 through the air compressor, and the first nitrogen adsorption bed 319 adsorbs nitrogen in the air. Then, the air after denitrogenation is sent to the second carbon dioxide adsorption bed 322 in the second capturing reactor 305, and the second carbon dioxide adsorption bed 322 adsorbs carbon dioxide. The fourth stop valve 316 is closed, and the air is discharged through the first gas discharge pipeline 311. Through the above arrangement, the first nitrogen adsorption bed 319 is filled with nitrogen, and the second carbon dioxide adsorption bed 322 is filled with carbon dioxide.

[0056] After the nitrogen and carbon dioxide filling treatment is completed, the nitrogen and carbon dioxide capturing device 301 can be recycled. The specific use steps are as follows: first, air is sent to the second nitrogen adsorption bed 321 in the second capturing reactor 305 through the air compressor, and the second nitrogen adsorption bed 321 adsorbs nitrogen. The heat generated is transferred to the second carbon dioxide adsorption bed 322 through the second isolation layer. The first stop valve 313, the fourth stop valve 316, and the sixth stop valve 318 are opened, and the second stop valve 314, the third stop valve 315, and the fifth stop valve 317 are closed. The carbon dioxide adsorbed by the second carbon dioxide adsorption bed 322 is desorbed and sent to the carbon dioxide buffer tank 302 through the fourth gas conveying pipeline 310. The air after denitrogenation is sent to the first carbon dioxide adsorption bed 320. The first carbon dioxide adsorption bed 320 adsorbs carbon dioxide in the air and generates heat, which is transferred to the first nitrogen adsorption bed 319 through the first isolation layer. The first nitrogen adsorption bed 319 desorbs nitrogen under the heat, and the nitrogen desorbed by the first nitrogen adsorption bed 319 is sent to the nitrogen buffer tank 303 through the first gas conveying pipeline 307. At the same time, the air after adsorption by the first carbon dioxide adsorption bed 320 is discharged through the second gas discharge pipeline 312.

[0057] The above process realizes the adsorption of carbon dioxide by the first carbon dioxide adsorption bed 320 and the adsorption of nitrogen by the second nitrogen adsorption bed 321. Air can be sent to the first nitrogen adsorption bed 319. The second stop valve 314, the third stop valve 315, and the fifth stop valve 317 are opened, and the first stop valve 313, the fourth stop valve 316, and the sixth stop valve 318 are closed. The first carbon dioxide adsorption bed 320 desorbs carbon dioxide, the second nitrogen adsorption bed 321 desorbs nitrogen, the first nitrogen adsorption bed 319 adsorbs nitrogen, and the second carbon dioxide adsorption bed 322 adsorbs carbon dioxide. Heat energy is coupled and recycled, and the energy consumption for desorption is reduced.

[0058] In addition to the above, the first carbon dioxide adsorption bed 320 that has been filled with carbon dioxide and the first nitrogen adsorption bed 319 that has not been filled with nitrogen can be directly assembled to form the first capture reactor 304, and the second nitrogen adsorption bed 321 that has been filled with nitrogen and the second carbon dioxide adsorption bed 321 that has not been filled with carbon dioxide can be directly assembled to form the second capture reactor 305.

[0059] As shown in Figure 6 , Figure 7 , in use, air is directly introduced into the first nitrogen adsorption bed 319 of the first capture reactor 304, and the first nitrogen adsorption bed 319 adsorbs nitrogen and generates heat, causing the carbon dioxide in the first carbon dioxide adsorption bed 320 to desorb. The denitrified air is transported into the second carbon dioxide adsorption bed 322 of the second capture reactor 305, and the second carbon dioxide adsorption bed 322 adsorbs carbon dioxide and generates heat, causing the nitrogen in the second nitrogen adsorption bed 321 to desorb.

[0060] After the above steps are completed, air is filled into the second nitrogen adsorption bed 321 of the second capture reactor 305, and the second nitrogen adsorption bed 321 adsorbs nitrogen in the air, while the carbon dioxide in the second carbon dioxide adsorption bed 322 desorbs; then denitrified air is introduced into the first carbon dioxide adsorption bed 320 of the first capture reactor 304, and the first carbon dioxide adsorption bed 320 adsorbs carbon dioxide, while the first carbon dioxide adsorption bed 320 desorbs carbon dioxide.

[0061] As a supplement to the technical scheme of the present application, the first capture reactor 304 and the second capture reactor 305 have the same structure and each include a cylindrical core bed 323 and an odd number of tubular beds. Each tubular bed is concentrically sleeved, and the tubular bed on the outside is sleeved outside the inner bed. The materials of adjacent beds are different. For example, when the core bed 323 is a nitrogen adsorption bed and the number of tubular beds is three, the first tubular bed 324 is sleeved outside the core bed 323, and the first tubular bed is a carbon dioxide adsorption bed; the second tubular bed 325 is sleeved outside the first tubular bed 324, and the second tubular bed is a nitrogen adsorption bed; and the third tubular bed 326 is sleeved outside the second tubular bed 325, and the third tubular bed is a carbon dioxide adsorption bed. Metal isolation plates are arranged between adjacent beds and on the outer surface of the outermost tubular bed. The metal isolation layer 306 is formed between adjacent metal isolation plates and the corresponding bed, and the outer periphery of the outermost tubular bed is covered by the metal isolation layer 306. The metal isolation layer 306 is used to achieve gas isolation.

[0062] For example, when the number of tubular beds is 3 and the core bed 323 is a carbon dioxide adsorption bed, the first layer of tubular beds 324 is sleeved outside the core bed 323, and the first layer of tubular beds is a nitrogen adsorption bed; the second layer of tubular beds 325 is sleeved outside the first layer of tubular beds 324, and the second layer of tubular beds is a carbon dioxide adsorption bed. The third layer of tubular beds 326 is sleeved outside the second layer of tubular beds 325, and the second layer of tubular beds is a nitrogen adsorption bed.

[0063] When the number of tubular beds is 1, the first layer of tubular beds 324 is sleeved outside the core bed 323, the core bed 323 is a nitrogen adsorption bed, and the first layer of tubular beds is a carbon dioxide adsorption bed.

[0064] As a supplement to the technical scheme of the application, the water electrolysis hydrogen production system further comprises an anode gas-water separator 203, a cathode gas-water separator 204, an oxygen remover 205, a dryer 206, and a first compressor 207.

[0065] The oxygen storage tank 201 and the proton exchange membrane electrolysis tank 200 are provided with an anode gas-water separator 203 for gas-water separation treatment of oxygen generated by the anode, thereby ensuring safe and efficient operation of subsequent equipment.

[0066] The hydrogen storage tank 202 and the proton exchange membrane electrolysis tank 200 are provided with, in sequence along the hydrogen conveying direction, a cathode gas-water separator 204, an oxygen remover 205, a dryer 206, and a first compressor 207. The cathode gas-water separator performs gas-water separation treatment on hydrogen generated by the cathode. The oxygen remover 205 removes oxygen mixed in the hydrogen. The dryer 206 further removes water mixed in the hydrogen. The first compressor 207 provides kinetic energy for gas conveying.

[0067] As a supplement to the technical scheme of the present application, a heat control system is further included, which comprises a seawater heat exchange pipeline 800. The seawater heat exchange pipeline 800 is sequentially connected with the proton exchange membrane electrolyzer 200, the first heat exchanger 405, the second heat exchanger 506 and the nitrogen and carbon dioxide capture device 301, forming a closed circulation cooling loop. The cooling water is driven to circulate in the seawater heat exchange pipeline 800 by the water pump 100, and when the cooling water flows through the proton exchange membrane electrolyzer 200, the first heat exchanger 405 and the second heat exchanger 506, heat exchange is performed with each device, effectively reducing the energy loss in the system operation. The cooling water carrying residual heat after heat exchange of the devices can be used as a backup heat source of the nitrogen and carbon dioxide capture device 301, participating in the gas desorption process, realizing the recycling of residual heat, and further improving the comprehensive energy utilization efficiency of the system. When the heat generated by the first nitrogen adsorption bed 319 in the first capture reactor 304 adsorbing nitrogen in the air cannot meet the desorption of carbon dioxide in the first carbon dioxide adsorption bed 320, or the heat generated by the first carbon dioxide adsorption bed 320 in the first capture reactor 304 adsorbing carbon dioxide in the denitrogenated air cannot meet the desorption of nitrogen in the first nitrogen adsorption bed 319, the heat control system can be used to supply heat to the corresponding bed, so that the bed can smoothly desorb nitrogen or carbon dioxide.

[0068] Preferably, water supply coils are arranged in the nitrogen adsorption bed and the carbon dioxide adsorption bed in the first capture reactor 304 and the second capture reactor 305, and the supply of hot water is controlled by valves.

[0069] Hot water can be supplied to the corresponding bed through the water supply coil, for example, when the first nitrogen adsorption bed 319 in the first capture reactor 304 adsorbs nitrogen in the air, the first carbon dioxide adsorption bed 320 in the first capture reactor 304 needs to absorb heat to realize the desorption of carbon dioxide, at this time hot water is input into the water supply coil of the first carbon dioxide adsorption bed 320, and the first carbon dioxide adsorption bed 320 rapidly absorbs heat and desorbs carbon dioxide. Through the arrangement of the water supply coil, the heat required for the desorption process of the corresponding bed is met.

[0070] Part of the heat in the water supply coil can be supplied by the heat control system, and the heat in the water supply coil can also be supplied by converting the electric energy of the power generation system into heat energy.

[0071] The hydrogen-ammonia-methanol co-production system based on the offshore energy island can be established at 35.0°N, 123.0°E in the northern sea area of the South China Sea, and the renewable energy power generation system includes a wind turbine with a rated power of 300 MW, a floating photovoltaic panel array with a power of 140 MW and a wave energy conversion device array with a power of 60 MW. When the wind speed in the sea area is 8 m / s and the solar irradiance is 700 W / m 2, the actual output power of the wind turbine generator, the floating photovoltaic panel array and the wave energy conversion device are 185 MW, 95 MW and 52 MW, respectively, i.e. the total output power of the renewable energy power generation system is 332 MW. 5 MW of the electric energy is preferentially supplied to the oil and gas drilling platform 1000, and the remaining 328 MW of the electric energy is used in the proton exchange membrane electrolyzer 200 in the water electrolysis hydrogen production system and all the compressors and water pumps 100 in the system. In the seawater desalination system, seawater at 20°C is pressurized to 10 MPa by the water pump 100 and then enters the reverse osmosis seawater desalination device 101 to be treated into fresh water. In the water electrolysis hydrogen production system, the fresh water is sent into the proton exchange membrane electrolyzer 200 operating at 80°C and 2.0 MPa, and in the proton exchange membrane electrolyzer 200, water is electrolyzed into oxygen and hydrogen by consuming electric energy. The yield of the generated oxygen and hydrogen is 8.95 kg / s and 1.25 kg / s, respectively. The oxygen is dehydrated by the anode gas-water separator 203 and stored in the oxygen storage tank 201, and is continuously supplied to the marine ranching 900 according to the demand. The hydrogen is dehydrated by the anode gas-water separator 203 and removed from the trace oxygen by the oxygen remover 205, and then enters the dryer 206 for further drying. The dried hydrogen is then pressurized by the first compressor 207 and stored in the hydrogen storage tank 202. Part of the hydrogen in the storage tank is pressurized to 20 MPa by the second compressor 700, and then adjusted by the second electric valve 705 and the first electric valve 704 to be delivered to the ammonia synthesis system and the methanol synthesis system at a mass flow rate of 0.5 kg / s, respectively.

[0072] Air is pressurized to 1 MPa by the third compressor 300 and enters the nitrogen and carbon dioxide capture reactor. In the nitrogen and carbon dioxide capture device 301, nitrogen and carbon dioxide in the air are adsorbed and stored in the nitrogen buffer tank 303 and the carbon dioxide buffer tank 302. The carbon dioxide is captured by the low-temperature solid adsorption technology with a weak base at a regeneration temperature of 80-100°C in the carbon dioxide capture device, and the cost of carbon dioxide capture is 180 dollars per ton, which is 20% lower than the direct air carbon dioxide capture cost of 225 dollars per ton. In the ammonia synthesis system, the nitrogen from the nitrogen buffer tank 303 is adjusted in flow rate by the third electric valve 404, pressurized to 20 MPa by the fourth compressor 402, and mixed with 0.5 kg / s of hydrogen to enter the first ammonia synthesis reactor 400. Hydrogen and nitrogen synthesize ammonia in the first ammonia synthesis reactor 400 under the reaction conditions of 375°C and 20 MPa. The ammonia generated by the reaction and the unreacted gas are maintained at 375°C by the first heat exchanger 405 and enter the second ammonia synthesis reactor 406 for further reaction to synthesize ammonia. The ammonia and unreacted gas flowing out of the second ammonia synthesis reactor 406 are separated by the ammonia separator 407, and the unreacted gas is recycled back to the first ammonia synthesis reactor 400 to continue to participate in the reaction. The separated ammonia with a flow rate of 4.25 kg / s is stored in the ammonia storage tank 401. The carbon dioxide in the carbon dioxide buffer tank 302 is adjusted in flow rate by the fourth electric valve 509, pressurized to 20 MPa by the fifth compressor 502, mixed with hydrogen from the electrolytic water hydrogen production system, and then enters the methanol synthesis reactor 500. Methanol is generated in the methanol synthesis reactor 500 at a temperature and pressure of 210°C and 20 MPa, respectively. The generated methanol flows through the methanol separator 505 and is separated from the unreacted gas. The unreacted gas is pressurized to 20 MPa by the sixth compressor 504, mixed with fresh hydrogen and carbon dioxide, and then enters the methanol synthesis reactor 500 for further reaction. The separated methanol is then purified in the pervaporation membrane unit 507 and stored in the methanol storage tank 501 with a purity of 99.9% and a flow rate of 8.0 kg / s. The hydrogen-ammonia-methanol co-production system based on the offshore energy island produces 1.58×104 tons of hydrogen, 1.34×105 tons of ammonia, and 2.52×105 tons of methanol per year. The system can provide 4.38×104 MWh of electric energy for offshore drilling platforms and 2.82×105 tons of oxygen for marine ranching 900. The cost of methanol is 260 dollars per ton, which is 13.3% lower than the current direct air capture carbon dioxide cost.

[0073] The above merely describes preferred embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art, according to the technical scheme and inventive concept of the present application, can make equivalent replacements or changes within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A hydrogen-ammonia-methanol cogeneration system based on marine renewable energy, characterized in that, This includes floating platforms for offshore energy islands, as well as seawater desalination systems, water electrolysis hydrogen production systems, nitrogen and carbon dioxide combined capture systems, ammonia synthesis systems, and methanol synthesis systems installed on these platforms. The seawater desalination system includes a reverse osmosis seawater desalination unit (101) for desalinating seawater; The water electrolysis hydrogen production system includes a proton exchange membrane electrolyzer (200), an oxygen storage tank (201), and a hydrogen storage tank (202); the proton exchange membrane electrolyzer (200) is connected to the reverse osmosis seawater desalination unit (101) through a pipeline, and the oxygen storage tank (201) and the hydrogen storage tank (202) are respectively connected to the proton exchange membrane electrolyzer through pipelines; The nitrogen and carbon dioxide combined capture system includes a third compressor (300), a nitrogen and carbon dioxide capture device (301), a carbon dioxide buffer tank (302), and a nitrogen buffer tank (303). The nitrogen and carbon dioxide capture device (301) includes a nitrogen adsorption mechanism and a carbon dioxide adsorption mechanism. The first compressor (207) is connected to the nitrogen adsorption mechanism, and the nitrogen adsorption mechanism is connected to the nitrogen buffer tank (303) through a pipeline. The outlet of the nitrogen adsorption mechanism is connected to the inlet of the carbon dioxide adsorption mechanism, and the carbon dioxide adsorption mechanism is connected to the carbon dioxide buffer tank (302) through a pipeline. The ammonia synthesis system includes a first ammonia synthesis reactor (400) and an ammonia storage tank (401); the first ammonia synthesis reactor (400) is connected to a nitrogen buffer tank (303) and a hydrogen storage tank (202) respectively, and the first ammonia synthesis reactor (400) and the ammonia storage tank (401) are connected by pipelines; The methanol synthesis system includes a methanol synthesis reactor (500) and a methanol storage tank (501); the methanol synthesis reactor (500) is connected to a carbon dioxide buffer tank (302) and a hydrogen storage tank (202) respectively, and the methanol synthesis reactor (500) and the methanol storage tank (501) are connected by pipelines.

2. The hydrogen-ammonia-methanol cogeneration system based on marine renewable energy according to claim 1, characterized in that, It also includes a power generation system installed on a floating platform of an offshore energy island. The power generation system includes a power generation device (600), a proton exchange membrane fuel cell stack (601), and a storage battery (602). The power generation device (600) is connected to various electrical equipment in the seawater desalination system, the water electrolysis hydrogen production system, the nitrogen and carbon dioxide combined capture system, the ammonia synthesis system, and the methanol synthesis system. The proton exchange membrane fuel cell stack (601) is connected to the hydrogen storage tank (202), which serves as a hydrogen source and is transported to the fuel cell stack along with the outside air to generate electricity. Both the power generation device (600) and the proton exchange membrane fuel cell stack (601) are connected to the battery (602), which stores electrical energy.

3. The hydrogen-ammonia-methanol cogeneration system based on marine renewable energy according to claim 1, characterized in that, The water electrolysis hydrogen production system also includes an anode gas-water separator (203), a cathode gas-water separator (204), a deaerator (205), a dryer (206), and a first compressor (207); An anode gas-water separator (203) is provided between the oxygen storage tank (201) and the proton exchange membrane electrolyzer (200). The hydrogen storage tank (202) and the proton exchange membrane electrolyzer (200) are sequentially provided with a cathode gas-water separator (204), a deaerator (205), a dryer (206), and a first compressor (207) along the hydrogen transport direction.

4. The hydrogen-ammonia-methanol cogeneration system based on marine renewable energy as described in claim 1, characterized in that, It also includes a hydrogen delivery system, and the ammonia synthesis system further includes a fourth compressor (402), a nitrogen delivery pipeline (403), and a third electric valve (404); the first ammonia synthesis reactor (400) is connected to a nitrogen buffer tank (303) through the nitrogen delivery pipeline (403), the fourth compressor (402) is installed on the nitrogen delivery pipeline (403), the third electric valve (404) is installed on the nitrogen delivery pipeline (403) between the nitrogen buffer tank (303) and the fourth compressor (402), the hydrogen storage tank (202) of the water electrolysis hydrogen production system is connected to the nitrogen delivery pipeline (403) through the hydrogen delivery system, so that hydrogen is delivered to the first ammonia synthesis reactor (400) through the nitrogen delivery pipeline (403), and the first ammonia synthesis reactor (400) is connected to the ammonia storage tank (401); The methanol synthesis system also includes a fifth compressor (502), a carbon dioxide delivery pipeline (503), and a fourth electric valve (509); the carbon dioxide buffer tank (302) is connected to the methanol synthesis reactor (500) through the carbon dioxide delivery pipeline (503), the fifth compressor (502) is installed on the carbon dioxide delivery pipeline (503), the hydrogen storage tank (202) of the water electrolysis hydrogen production system is connected to the carbon dioxide delivery pipeline (503) through the hydrogen delivery system, so that hydrogen and carbon dioxide are delivered together through the carbon dioxide delivery pipeline (503) to the methanol synthesis reactor (500) to react and generate methanol, and the methanol synthesis reactor (500) is connected to the methanol storage tank (501).

5. The hydrogen-ammonia-methanol co-production system based on marine renewable energy according to claim 4, characterized in that, The hydrogen delivery system includes a second compressor (700), a main hydrogen delivery pipeline (701), a first hydrogen delivery branch pipeline (702), a second hydrogen delivery branch pipeline (703), a first electric valve (704), and a second electric valve (705). The second compressor (700) is connected to a hydrogen storage tank (202) through the main hydrogen delivery pipeline (701). One end of the first hydrogen delivery branch pipeline (702) is connected to the second compressor (700), and the other end is connected to a carbon dioxide delivery pipeline (503). The first electric valve (704) is installed on the first hydrogen delivery branch pipeline (702). One end of the second hydrogen delivery branch pipeline (703) is connected to the second compressor (700), and the other end is connected to a nitrogen delivery pipeline (403). The second electric valve (705) is installed on the second hydrogen delivery branch pipeline (703).

6. The hydrogen-ammonia-methanol co-production system based on marine renewable energy according to claim 5, characterized in that, The ammonia synthesis system further includes a first heat exchanger (405), a second ammonia synthesis reactor (406), and an ammonia separator (407). The first heat exchanger (405) is provided between the first ammonia synthesis reactor (400) and the second ammonia synthesis reactor (406). The second ammonia synthesis reactor (406) is connected to the ammonia separator (407). The ammonia separator (407) is connected to the first ammonia synthesis reactor (400) and the ammonia storage tank (401) respectively.

7. The hydrogen-ammonia-methanol cogeneration system based on marine renewable energy according to claim 6, characterized in that, The methanol synthesis system also includes a sixth compressor (504), a methanol separator (505), a second heat exchanger (506), a pervaporation membrane unit (507), and a reflux pipeline (508). The methanol synthesis reactor (500) is connected to the methanol separator (505), the methanol separator (505) is connected to the carbon dioxide delivery pipeline (503) through the reflux pipeline (508), the sixth compressor (504) is installed on the carbon dioxide delivery pipeline (503), the methanol separator (505) is connected to the methanol storage tank (501) through the methanol delivery pipeline, and the methanol delivery pipeline is equipped with a second heat exchanger (506) and a permeate membrane evaporation unit.

8. The hydrogen-ammonia-methanol cogeneration system based on marine renewable energy according to claim 7, characterized in that, It also includes a heat control system, which includes a seawater heat exchange pipeline (800); the seawater heat exchange pipeline (800) is connected in sequence to a proton exchange membrane electrolyzer (200), a first heat exchanger (405), a second heat exchanger (506) and a nitrogen and carbon dioxide capture device (301) to form a closed-loop cooling circuit.

9. The hydrogen-ammonia-methanol cogeneration system based on marine renewable energy according to claim 1, characterized in that, The nitrogen and carbon dioxide capture device (301) includes a first capture reactor (304), a second capture reactor (305), a metal isolation layer (306), a first gas delivery pipeline (307), a second gas delivery pipeline (308), a third gas delivery pipeline (309), a fourth gas delivery pipeline (310), a first gas discharge pipeline (311), a second gas discharge pipeline (312), a first shut-off valve (313), a second shut-off valve (314), a third shut-off valve (315), a fourth shut-off valve (316), a fifth shut-off valve (317), and a sixth shut-off valve (318). The first trapping reactor (304) includes a first nitrogen adsorption bed (319) and a first carbon dioxide adsorption bed (320) arranged adjacent to each other, and the second trapping reactor (305) includes a second nitrogen adsorption bed (321) and a second carbon dioxide adsorption bed (322) arranged adjacent to each other; each adsorption bed of the first trapping reactor (304) and the second trapping reactor (305) is covered with a metal isolation layer (306) to isolate the gas, and each adsorption bed is provided with an inlet and an outlet, and the metal isolation layer (306) located at the inlet and outlet of the adsorption bed is provided with through holes; The air inlets of the first nitrogen adsorption bed (319) and the second nitrogen adsorption bed (321) are both connected to the third compressor (300) through pipelines; The outlet of the first nitrogen adsorption bed (319) is connected to the inlet of the second carbon dioxide adsorption bed (322) through a pipeline. The first nitrogen adsorption bed (319) is connected to the nitrogen buffer tank (303) through the first gas delivery pipeline (307). The first shut-off valve (313) is installed on the first gas delivery pipeline (307). The second nitrogen adsorption bed (321) is connected to the nitrogen buffer tank (303) through the second gas delivery pipeline (308). The second shut-off valve (314) is installed on the second gas delivery pipeline (307). The first carbon dioxide adsorption bed (320) is connected to the carbon dioxide buffer tank (302) through the third gas transmission pipeline (309), and the third shut-off valve (315) is installed on the third gas transmission pipeline (309); the second carbon dioxide adsorption bed (322) is connected to the carbon dioxide buffer tank (302) through the fourth gas transmission pipeline (310), and the fourth shut-off valve (316) is installed on the third gas transmission pipeline (309); The outlet of the first nitrogen adsorption bed (319) is connected to the inlet of the second carbon dioxide adsorption bed (322) through a pipeline. The outlet of the second carbon dioxide adsorption bed (322) is connected to a first gas discharge pipeline (311), and a fifth shut-off valve (317) is provided on the first gas discharge pipeline (311). The outlet of the second nitrogen adsorption bed (321) is connected to the inlet of the first carbon dioxide adsorption bed (320) through a pipeline. The outlet of the first carbon dioxide adsorption bed (320) is connected to a second gas discharge pipeline (312). A sixth shut-off valve (318) is provided on the first gas discharge pipeline (311). The nitrogen adsorption bed is made of metal-organic framework MOF-801, which generates heat when adsorbing nitrogen. The carbon dioxide adsorption bed is made of K2CO3 / ZrO2 solid adsorbent, which generates heat when adsorbing carbon dioxide. The nitrogen adsorption mechanism is a nitrogen adsorption bed, and the carbon dioxide adsorption mechanism is a carbon dioxide adsorption bed.

10. The hydrogen-ammonia-methanol cogeneration system based on marine renewable energy according to claim 9, characterized in that, The first trapping reactor (304) and the second trapping reactor (305) have the same structure, both including a cylindrical core bed (323) and an odd number of tubular beds; the tubular beds are concentrically nested, with the outermost tubular bed nested outside the innermost bed, the materials of adjacent two beds are different, and metal isolation plates are provided between adjacent two beds and on the outer surface of the outermost tubular bed.

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