Electrolytic hydrogen production and ammonia synthesis system and method

Abstract

The invention provides an electrolytic hydrogen production and ammonia synthesis system and method. The system comprises a solid oxide electrolytic tank, an ammonia synthesis device, a heat exchange unit and an ammonia collection device, wherein the solid oxide electrolytic tank is provided with a water vapor feeding hole, an air feeding hole and a hydrogen-nitrogen mixed gas outlet; a hydrogen-nitrogen mixed gas outlet of the solid oxide electrolytic tank is connected with an inlet of the ammonia synthesis device, an outlet of the ammonia synthesis device is connected with an inlet of the heat exchange unit, an ammonia gas outlet of the heat exchange unit is connected with an inlet of the ammonia collection device, and a water vapor outlet of the heat exchange unit is connected with a water vapor feeding port of the solid oxide electrolytic tank. A gas outlet of the ammonia collecting device is connected with an inlet of the ammonia synthesizing device. The electrolytic reactor provided by the invention can simultaneously realize an electrolytic hydrogen production function and an air separation nitrogen production function, the whole process of the system is simplified, the energy consumption of air separation nitrogen production can be saved, and the total energy consumption of the system is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of renewable energy and synthetic ammonia technology, in particular to an electrolytic hydrogen synthesis ammonia system and method. BACKGROUND

[0002] The synthetic ammonia process refers to an industrial process of synthesizing ammonia by chemical reaction of nitrogen and hydrogen. The current synthetic ammonia process has problems of high energy consumption and complex system.

[0003] CN113479905B discloses a renewable energy synthetic ammonia system, which comprises a synthetic ammonia tower, an electrolytic water device, a nitrogen source providing device, a mixer, an ammonia condenser group, a gas-liquid separator and a tank; the nitrogen source of the system is air separation, and the hydrogen source is water electrolysis; the system is relatively complex, and the temperature and pressure of electrolytic hydrogen and synthetic ammonia are difficult to match.

[0004] CN110156047B discloses a synthetic ammonia method coupled with a solid oxide electrolysis cell and a fossil fuel synthetic ammonia system. The method comprises the following steps: hydrogen is prepared from fossil fuel, then mixed with nitrogen to perform a synthetic ammonia reaction; then the carbon dioxide gas generated in the hydrogen preparation step is collected, mixed with water vapor, and introduced into a solid oxide electrolysis cell for electrolysis, and the generated gas is returned to the hydrogen preparation step for recycling; the hydrogen preparation of this technology is fossil fuel hydrogen preparation, which is difficult to completely avoid carbon emissions.

[0005] CN218088976U discloses a container type synthetic ammonia system, which comprises an electrolytic water hydrogen production system, a hydrogen purification system and an ammonia synthesis system. The hydrogen of the system comes from the electrolytic water hydrogen production system, and the system only has a hydrogen production function. Since no nitrogen preparation facility is configured, the system is only suitable for scenes with a nitrogen source. SUMMARY

[0006] In order to solve the problems existing in the prior art, the present application provides an electrolytic hydrogen synthesis ammonia system and method. The system can realize the functions of electrolytic hydrogen production and air separation nitrogen production by using a solid oxide electrolysis cell, without the need for a low-temperature air separation nitrogen process, simplifying the overall process of the system and reducing the total energy consumption of the system.

[0007] In order to solve the above problems, according to the first aspect of the present application, an electrolytic hydrogen synthesis ammonia system is provided, which comprises:

[0008] a solid oxide electrolysis cell, an ammonia synthesis device, a heat exchange unit and an ammonia collecting device;

[0009] The solid oxide electrolysis cell has a water vapor inlet, an air inlet and a hydrogen-nitrogen mixed gas outlet.

[0010] The hydrogen-nitrogen mixed gas outlet of the solid oxide electrolysis cell is connected with the inlet of the ammonia synthesis device, the outlet of the ammonia synthesis device is connected with the inlet of the heat exchange unit, the ammonia gas outlet of the heat exchange unit is connected with the inlet of the ammonia collecting device, the water vapor outlet of the heat exchange unit is connected with the water vapor feed port of the solid oxide electrolysis cell, and the gas outlet of the ammonia collecting device is connected with the inlet of the ammonia synthesis device.

[0011] In some preferred embodiments of the present application, the ammonia synthesis device comprises a gas compression device and an ammonia synthesizer connected in series; the gas compression device has a hydrogen-nitrogen mixed gas inlet and a compressed gas outlet; the ammonia synthesizer has a compressed gas inlet and an ammonia gas outlet; the hydrogen-nitrogen mixed gas inlet is connected with the hydrogen-nitrogen mixed gas outlet of the solid oxide electrolysis cell, and the compressed gas outlet of the gas compression device is connected with the inlet of the heat exchange unit.

[0012] In some preferred embodiments of the present application, the heat exchange unit comprises a waste heat utilization device, a cooling device and an ammonia cooler connected in series; the waste heat utilization device has a waste heat gas first inlet, a waste heat gas first outlet, a hot water inlet and a water vapor outlet; the cooling device has a waste heat gas second inlet, a waste heat gas second outlet, a cold water inlet and a hot water outlet; the ammonia cooler has an ammonia gas inlet and a cooling gas outlet; wherein the waste heat gas first inlet is connected with the outlet of the ammonia synthesis device, the waste heat gas first outlet is connected with the waste heat gas second inlet, the waste heat gas second outlet is connected with the ammonia gas inlet, and the cooling gas outlet is connected with the inlet of the ammonia collecting device; the hot water outlet of the cooling device is connected with the hot water inlet of the waste heat utilization device, and the water vapor outlet is connected with the water vapor feed port of the solid oxide electrolysis cell. The waste heat utilization device uses the product gas from the ammonia synthesis device to heat the hot water to obtain water vapor, which is used in the solid oxide electrolysis cell, and the cooling device uses the cooled product gas from the waste heat utilization device to heat the cold water to generate water vapor for input into the waste heat utilization device.

[0013] In some preferred embodiments of the present application, the ammonia collecting device comprises an ammonia separator and an ammonia storage; the ammonia separator has a cooling gas inlet, a separated gas outlet and a separated liquid outlet, and the ammonia storage is provided with a liquid inlet; wherein the cooling gas inlet is connected with the outlet of the heat exchange unit, the separated gas outlet is connected with the inlet of the ammonia synthesis device, and the separated liquid outlet is connected with the liquid inlet of the ammonia storage (the ammonia storage is used to store liquid ammonia).

[0014] The system can realize the functions of electrolytic hydrogen production and air separation nitrogen production by using the solid oxide electrolysis cell, without the need for low-temperature air separation nitrogen production process, simplifying the overall process of the system and reducing the total energy consumption of the system.

[0015] In the system, the ammonia outlet of the ammonia synthesis device is connected with the heat exchange unit; the gas taken out from the ammonia outlet has residual heat, so that the gas can enter the heat exchange unit, thereby fully utilizing the heat energy and reducing the energy consumption.

[0016] In some preferred embodiments of the present application, the gas outlet of the ammonia separator is connected with the hydrogen-nitrogen mixed gas inlet of the gas compression device. The circulating gas can be obtained through the gas outlet of the ammonia separator, and the circulating gas is a mixed gas of hydrogen and nitrogen, which can be input into the ammonia synthesis device for recycling.

[0017] In some preferred embodiments of the present application, the water vapor outlet of the residual heat utilization device of the heat exchange unit is connected with the water vapor inlet of the solid oxide electrolysis cell. According to such an embodiment, the water vapor material can be fully utilized to realize internal circulation of the material.

[0018] In some preferred embodiments of the present application, the solid oxide electrolysis cell is composed of more than one solid oxide cell in parallel or in series. Preferably, such a modular design is used to flexibly adjust the production scale of synthetic ammonia.

[0019] In some preferred embodiments of the present application, the cold water inlet of the cooling device is used to input cold water to prepare hot water and water vapor through heat exchange. The cold water in the present application can be water at room temperature, and the temperature can be 15-35°C or other temperatures convenient for operators to obtain.

[0020] The present application also provides an electrolytic hydrogen synthesis ammonia method realized according to the above system.

[0021] In some preferred embodiments of the present application, air is introduced into the cathode of the solid oxide electrolysis cell through the air inlet, and water vapor is introduced into the cathode of the solid oxide electrolysis cell through the water vapor inlet; an electrolysis reaction is performed, a first hydrogen-nitrogen mixed gas is taken out from the anode of the solid oxide electrolysis cell, the first hydrogen-nitrogen mixed gas is led out through the hydrogen-nitrogen mixed gas outlet, and enters the gas compression device for compression treatment to obtain compressed gas.

[0022] The compressed gas is sent into the ammonia synthesizer to perform a synthetic ammonia reaction to obtain product gas.

[0023] The product gas is sent into the heat exchange unit to perform heat exchange with water to obtain heated water material and cooled product gas.

[0024] The cooled product gas is sent into the ammonia collection device to obtain liquid ammonia and a second hydrogen-nitrogen mixed gas.

[0025] In some preferred embodiments of the present application, the temperature of the synthetic ammonia reaction is 400-500°C, and the operating pressure is 7-15 MPa.

[0026] The method provided by the application can sufficiently realize recycling of materials and energy and reduce total energy consumption of the system.

[0027] In some preferred embodiments of the application, the temperature of the electrolysis reaction is 650-850℃. According to the preferred method of the application, the utilization of heat is more sufficient.

[0028] In some preferred embodiments of the application, in the electrolysis reaction, the molar ratio of the water vapor to the air is 1:2-4.

[0029] In some preferred embodiments of the application, the circulating gas is obtained via a gas outlet of the ammonia separator, and the circulating gas is sent into a compressed gas inlet of the gas compression device; and in the gas compression device, the molar ratio of the first hydrogen-nitrogen mixed gas to the circulating gas is 1:2-3.5.

[0030] In some preferred embodiments of the application, the solid oxide electrolysis cell is powered by renewable electricity.

[0031] Compared with the prior art, the application has the beneficial technical effects including:

[0032] The electrolysis stack provided by the application can simultaneously realize the functions of electrolytic hydrogen production and air separation nitrogen production, simplifies the overall process of the system, and can save the air separation nitrogen unit, simplifies the system process, and can realize synthesis of ammonia only by using water and air, can obtain a high hydrogen conversion rate, can fully utilize materials and energy, reduce energy consumption, improve the integration of the system, and has strong application scene applicability. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 FIG. 1 is a schematic diagram of an electrolytic hydrogen production and ammonia synthesis system according to the application.

[0034] The reference signs include:

[0035] 1-solid oxide electrolysis cell, 2-ammonia synthesis device, 3-heat exchange unit, 4-ammonia collection device;

[0036] 21-gas compression device, 22-ammonia synthesizer, 31-waste heat utilization device, 32-cooling device, 33-ammonia cooler, 41-ammonia separator, 42-ammonia storage;

[0037] 101 - water vapor inlet, 102 - air inlet, 103 - hydrogen-nitrogen mixture outlet; 2101 - hydrogen-nitrogen mixture inlet, 2102 - compressed gas outlet, 2201 - compressed gas inlet, 2202 - ammonia gas outlet, 3101 - first waste heat gas inlet, 3102 - first waste heat gas outlet, 3103 - hot water inlet, 3104 - water vapor outlet, 3201 - second waste heat gas inlet, 3202 - second waste heat gas outlet, 3203 - cold water inlet, 3204 - hot water outlet, 3301 - ammonia gas inlet, 3302 - cooling gas outlet, 4101 - cooling gas inlet, 4102 - separated gas outlet, 4103 - separated liquid outlet. DETAILED DESCRIPTION

[0038] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present application, the technical solutions of the present application will be described in detail below, but it should not be understood as limiting the scope of the present application.

[0039] Example 1

[0040] The present embodiment provides a renewable energy electrolytic hydrogen synthesis ammonia system. The schematic diagram of the system is shown in Figure 1 .

[0041] The system comprises a solid oxide electrolysis cell 1, an ammonia synthesis device 2, a heat exchange unit 3 and an ammonia collection device 4.

[0042] The solid oxide electrolysis cell 1 has a water vapor inlet 101, an air inlet 102 and a hydrogen-nitrogen mixture outlet 103.

[0043] The ammonia synthesis device 2 comprises a gas compression device 21 and an ammonia synthesizer 22 connected in series; the gas compression device 21 has a hydrogen-nitrogen mixture inlet 2101 and a compressed gas outlet 2102, and the ammonia synthesizer 22 has a compressed gas inlet 2201 and an ammonia gas outlet 2202.

[0044] The heat exchange unit 3 comprises a waste heat utilization device 31, a cooling device 32 and an ammonia cooler 33 connected in series; the waste heat utilization device 31 has a first waste heat gas inlet 3101, a first waste heat gas outlet 3102, a hot water inlet 3103 and a water vapor outlet 3104; the cooling device 32 has a second waste heat gas inlet 3201, a second waste heat gas outlet 3202, a cold water inlet 3203 and a hot water outlet 3204; the ammonia cooler 33 has an ammonia gas inlet 3301 and a cooling gas outlet 3302.

[0045] The ammonia collection device 4 comprises an ammonia separator 41 and an ammonia storage 42; the ammonia separator 41 has a cooling gas inlet 4101, a separated gas outlet 4102 and a separated liquid outlet 4103, and the ammonia storage 42 is provided with a liquid inlet 4201.

[0046] The water vapor feeding port 101 and the air feeding port 102 of the solid oxide electrolysis cell 1 are respectively used for inputting water vapor and air raw materials, the hydrogen-nitrogen mixed gas outlet 103 is connected with the hydrogen-nitrogen mixed gas inlet 2101 of the gas compression device 21, the compressed gas outlet 2102 of the gas compression device 21 is connected with the compressed gas inlet 2201 of the ammonia synthesizer 22, the ammonia gas outlet 2202 of the ammonia synthesizer 22 is connected with the first waste heat gas inlet 3101 of the waste heat utilization device 31, the first waste heat gas outlet 3102 of the waste heat utilization device 31 is connected with the second waste heat gas inlet 3201 of the cooling device 32, the second waste heat gas outlet 3202 of the cooling device 32 is connected with the ammonia gas inlet 3301 of the ammonia cooler 33, the cooling gas outlet 3302 of the ammonia cooler 33 is connected with the cooling gas inlet 4101 of the ammonia separator 41, the separated gas outlet 4102 of the ammonia separator 41 is connected with the hydrogen-nitrogen mixed gas inlet 2101 of the gas compression device 21, and the separated liquid outlet 4103 of the ammonia separator 41 is connected with the liquid inlet 4201 of the ammonia storage 42;

[0047] The cooling water inlet 3203 of the cooling device 32 is used for inputting cooling water, the hot water outlet 3204 of the cooling device 32 is connected with the hot water inlet 3103 of the waste heat utilization device 31, and the water vapor outlet 3104 of the waste heat utilization device 31 is connected with the water vapor feeding port 101 of the solid oxide electrolysis cell 1;

[0048] The solid oxide electrolysis cell 1 is composed of more than one solid oxide cell in parallel or in series.

[0049] The method for synthesizing ammonia by using the above system is as follows:

[0050] The air and the water vapor (including a direct water vapor source and water vapor from the waste heat utilization device 31) enter the cathode of the solid oxide electrolysis cell 1 through the air feeding port 102 and the water vapor feeding port 101 of the solid oxide electrolysis cell 1 respectively, the feeding molar ratio of the air and the water vapor is 1 / 2, and the electrolysis reaction is carried out at 750℃; the first hydrogen-nitrogen mixed gas is generated at the anode of the solid oxide electrolysis cell 1 and is extracted through the hydrogen-nitrogen mixed gas outlet 103, the temperature of the first hydrogen-nitrogen mixed gas is 720℃, and the pressure is 0.1 MPa;

[0051] The first hydrogen-nitrogen mixed gas is mixed with the circulating gas circulated back from the ammonia separator 41, wherein the molar ratio of the first hydrogen-nitrogen mixed gas to the circulating gas is 1 / 3, the mixed gas enters the other compression device 21 through the hydrogen-nitrogen mixed gas inlet 2101; after being compressed by the gas compression device 21, the mixed gas exits through the compressed gas outlet 2102 and enters the ammonia synthesizer 22 through the compressed gas inlet 2201;

[0052] The ammonia synthesizer 22 is an ammonia synthesis reactor, the control pressure is 7 MPa, the temperature is 450 ℃, the hydrogen conversion rate is 30%, and the total energy consumption per ton of ammonia is 29 MJ / t.

[0053] The product gas from the ammonia gas outlet 2202 of the ammonia synthesizer 22 first enters the waste heat utilization device 31 through the waste heat gas first inlet 3101, and through heat exchange, the hot water in the waste heat utilization device 31 is converted into water vapor at 400 ℃, then exits through the waste heat gas first outlet 3102, and enters the cooling device 32 through the waste heat gas second inlet 3201, and through heat exchange, the cold water in the cooling device 32 is heated to hot water at 60 ℃, then exits through the waste heat gas second outlet 3202, and is cooled by the ammonia cooler 33 through the ammonia gas inlet 3301, the cooled mixed gas exits through the cooling gas outlet 3302, and enters the ammonia separator 41 through the cooling gas inlet 4101 for gas-liquid separation, the separated liquid ammonia exits through the separation liquid outlet 4103, and enters the ammonia storage 42 through the liquid inlet 4201, and the gaseous hydrogen-nitrogen mixed gas exits through the separation gas outlet 4102, and is mixed with the hydrogen-nitrogen mixed gas from the hydrogen-nitrogen mixed gas outlet 103 of the solid oxide electrolysis cell 1.

[0054] Example 2

[0055] The embodiment provides a renewable energy electrolysis hydrogen synthesis ammonia process, which is different from the embodiment 1 in that process conditions are different, and specifically includes the following:

[0056] In the electrolysis reaction, the molar ratio of air to water vapor is 1 / 3, and the reaction is carried out at 650 ℃. The temperature of the first hydrogen-nitrogen mixed gas collected is 620 ℃, and the pressure is 0.12 MPa. The molar ratio of the first hydrogen-nitrogen mixed gas to the circulating gas is 1 / 2.

[0057] In the ammonia synthesis reaction, the pressure of the synthesis tower is 8 MPa, the temperature is 400 ℃, the hydrogen conversion rate is 18%, and the total energy consumption per ton of ammonia is 31 MJ / t.

[0058] In the heat exchange process, the waste heat utilization device 31 converts the hot water into water vapor at 350 ℃, and then the water vapor enters the cooling device 32 to heat the cold water to hot water at 60 ℃.

[0059] Example 3

[0060] The embodiment provides a renewable energy electrolysis hydrogen synthesis ammonia process, which is different from the embodiment 1 in that process conditions are different, and specifically includes the following:

[0061] In the electrolysis reaction, the molar ratio of air to water vapor is 1 / 2.5, and the reaction is carried out at 850 ℃. The temperature of the first hydrogen-nitrogen mixed gas collected is 820 ℃, and the pressure is 0.13 MPa. The molar ratio of the first hydrogen-nitrogen mixed gas to the circulating gas is 1 / 2.5.

[0062] In the ammonia synthesis reaction, the pressure in the synthesis tower is 11 MPa, the temperature is 500℃, the hydrogen conversion rate is 32%, and the total energy consumption per ton of ammonia is 28 MJ / t.

[0063] During the heat exchange process, the waste heat utilization device 31 converts the hot water into 450°C steam, which then enters the cooling device 32 to heat the cold water to 60°C.

[0064] Example 4

[0065] This embodiment provides a renewable energy electrolysis process for hydrogen production and ammonia synthesis, which differs from Embodiment 1 in that the process conditions are different, specifically including:

[0066] In the electrolysis reaction, the molar ratio of air to water vapor is 1 / 4, and the reaction is carried out at 650℃. The temperature of the first hydrogen-nitrogen mixture extracted is 620℃, and the pressure is 0.1 MPa. The molar ratio of the first hydrogen-nitrogen mixture to the circulating gas is 1 / 3.

[0067] In the ammonia synthesis reaction, the pressure in the synthesis tower is 15 MPa, the temperature is 460℃, the hydrogen conversion rate is 34%, and the total energy consumption per ton of ammonia is 28.5 MJ / t.

[0068] During the heat exchange process, the waste heat utilization device 31 converts the hot water into water vapor at 410°C, which then enters the cooling device 32 to heat the cold water to 60°C.

[0069] Example 5

[0070] This embodiment provides a renewable energy electrolysis process for hydrogen production and ammonia synthesis, which differs from Embodiment 1 in that the process conditions are different, specifically including:

[0071] In the electrolysis reaction, the molar ratio of air to water vapor is 1 / 2.4, and the reaction is carried out at 700℃. The temperature of the first hydrogen-nitrogen mixture extracted is 680℃, and the pressure is 0.1 MPa. The molar ratio of the first hydrogen-nitrogen mixture to the circulating gas is 1 / 3.5.

[0072] In the ammonia synthesis reaction, the pressure in the synthesis tower is 10 MPa, the temperature is 420℃, the hydrogen conversion rate is 22%, and the total energy consumption per ton of ammonia is 30.5 MJ / t.

[0073] During the heat exchange process, the waste heat utilization device 31 converts the hot water into 370°C water vapor, which then enters the cooling device 32 to heat the cold water to 50°C.

[0074] Example 6

[0075] This embodiment provides a renewable energy electrolysis process for hydrogen production and ammonia synthesis, which differs from Embodiment 1 in that the process conditions are different, specifically including:

[0076] In the electrolysis reaction, the molar ratio of air to water vapor is 1 / 3.6, and the reaction is carried out at 800℃. The temperature of the first hydrogen-nitrogen mixture extracted is 780℃, and the pressure is 0.12 MPa. The molar ratio of the first hydrogen-nitrogen mixture to the circulating gas is 1 / 2.8.

[0077] In the ammonia synthesis reaction, the pressure in the synthesis tower is 8 MPa, the temperature is 430℃, the hydrogen conversion rate is 20%, and the total energy consumption per ton of ammonia is 30 MJ / t.

[0078] During the heat exchange process, the waste heat utilization device 31 converts the hot water into 380°C water vapor, which then enters the cooling device 32 to heat the cold water to 60°C.

Claims

1. An electrolytic hydrogen production and ammonia synthesis system, characterized in that, include: Solid oxide electrolytic cell (1), ammonia synthesis device (2), heat exchange unit (3) and ammonia collection device (4); The solid oxide electrolytic cell (1) has a steam inlet (101), an air inlet (102), and a hydrogen-nitrogen mixed gas outlet (103); The hydrogen-nitrogen mixed gas outlet (103) of the solid oxide electrolytic cell (1) is connected to the inlet of the ammonia synthesis device (2), the outlet of the ammonia synthesis device (2) is connected to the inlet of the heat exchange unit (3), the ammonia outlet of the heat exchange unit (3) is connected to the inlet of the ammonia collection device (4), the steam outlet of the heat exchange unit (3) is connected to the steam feed port (101) of the solid oxide electrolytic cell (1), and the gas outlet of the ammonia collection device (4) is connected to the inlet of the ammonia synthesis device (2).

2. The electrolytic hydrogen production and ammonia synthesis system according to claim 1, characterized in that, The ammonia synthesis device (2) includes a gas compression device (21) and an ammonia synthesizer (22) connected in series; the gas compression device (21) has a hydrogen-nitrogen mixed gas inlet (2101) and a compressed gas outlet (2102); the ammonia synthesizer (22) has a compressed gas inlet (2201) and an ammonia outlet (2202); The hydrogen-nitrogen mixed gas inlet (2101) is connected to the hydrogen-nitrogen mixed gas outlet (103) of the solid oxide electrolysis cell (1), and the compressed gas outlet (2102) of the gas compression device (21) is connected to the inlet of the heat exchange unit (3).

3. The electrolytic hydrogen production and ammonia synthesis system according to claim 1, characterized in that, The heat exchange unit (3) includes a waste heat utilization device (31), a cooling device (32), and an ammonia cooler (33) connected in series. The waste heat utilization device (31) has a first waste heat gas inlet (3101), a first waste heat gas outlet (3102), a hot water inlet (3103), and a steam outlet (3104). The cooling device (32) has a second waste heat gas inlet (3201), a second waste heat gas outlet (3202), a cold water inlet (3203), and a hot water outlet (3204). The ammonia cooler (33) has an ammonia gas inlet (3301) and a cooling gas outlet (3302). The first waste heat gas inlet (3101) is connected to the outlet of the ammonia synthesis device (2), the first waste heat gas outlet (3102) is connected to the second waste heat gas inlet (3201), the second waste heat gas outlet (3202) is connected to the ammonia inlet (3301), and the cooling gas outlet (3302) is connected to the inlet of the ammonia collection device (4). The hot water outlet (3204) is connected to the hot water inlet (3103), and the steam outlet (3104) is connected to the steam feed inlet (101) of the solid oxide electrolysis cell (1).

4. The electrolytic hydrogen production and ammonia synthesis system according to claim 1, characterized in that, The ammonia collection device (4) includes an ammonia separator (41) and an ammonia storage device (42); the ammonia separator (41) has a cooling gas inlet (4101), a separated gas outlet (4102) and a separated liquid outlet (4103), and the ammonia storage device (42) is provided with a liquid inlet (4201); The cooling gas inlet (4101) is connected to the outlet of the heat exchange unit (3), the separated gas outlet (4102) is connected to the inlet of the ammonia synthesis device (2), and the separated liquid outlet (4103) is connected to the liquid inlet (4201).

5. A method for electrolytic hydrogen production and ammonia synthesis, characterized in that, The process is carried out using the electrolytic hydrogen production and ammonia synthesis system according to any one of claims 1 to 4.

6. The method for electrolytic hydrogen production and ammonia synthesis according to claim 5, characterized in that, include: Air is introduced into the cathode of the solid oxide electrolytic cell (1) through the air inlet (102), and water vapor is introduced into the cathode of the solid oxide electrolytic cell (1) through the water vapor inlet (101); an electrolysis reaction is carried out, and a first hydrogen-nitrogen mixture is extracted from the anode of the solid oxide electrolytic cell (1). The first hydrogen-nitrogen mixture is discharged through the hydrogen-nitrogen mixture outlet (103) and enters the gas compression device (21) for compression treatment to obtain compressed gas; The compressed gas is fed into an ammonia synthesizer (22) to carry out an ammonia synthesis reaction and obtain product gas; The product gas is sent into the heat exchange unit (3) to exchange heat with water, so as to obtain heated water material and cooled product gas. The cooled product gas is sent into an ammonia collection device (4) to obtain liquid ammonia and a second hydrogen-nitrogen mixture.

7. The method for electrolytic hydrogen production and ammonia synthesis according to claim 6, characterized in that, The ammonia synthesis reaction is carried out at a temperature of 400–500°C and an operating pressure of 7–15 MPa.

8. The method for electrolytic hydrogen production and ammonia synthesis according to claim 6, characterized in that, The electrolysis reaction is carried out at a temperature of 650–850°C.

9. The method for electrolytic hydrogen production and ammonia synthesis according to claim 6, characterized in that, In the electrolysis reaction, the molar ratio of water vapor to air is 1:2 to 4.

10. The method for electrolytic hydrogen production and ammonia synthesis according to claim 6, characterized in that, A circulating gas is obtained through the gas outlet (4102) of the ammonia separator (41), and the circulating gas is sent to the hydrogen-nitrogen mixture inlet (2101) of the gas compression device (21); and in the gas compression device (21), the molar ratio of the first hydrogen-nitrogen mixture to the circulating gas is 1:2 to 3.5.

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