CN217808782U - Synthetic ammonia coupling water electrolysis hydrogen production system - Google Patents

Abstract

The application provides a synthetic ammonia coupling water electrolysis hydrogen production system, which couples a synthetic ammonia system into the water electrolysis hydrogen production system, and is provided with a heat exchanger which is respectively connected with the synthetic ammonia system and the water electrolysis hydrogen production system so as to collect coolant after heat absorption in the system. The coolant after absorbing heat preheats the alkali liquor in the alkaline electrolytic cell, and the temperature rise process of the alkali liquor before starting the alkaline electrolytic cell is reduced, so that the alkaline electrolytic cell is quickly started, and the energy consumption is reduced. The power supply can better adapt to the fluctuation of a renewable energy power supply so as to keep high energy conversion efficiency and improve the overall energy efficiency. Furthermore, the coolant after absorbing heat cools the synthetic ammonia coupling electrolyzed water hydrogen production system again after cooling the low-temperature alkali liquor, so that the coolant can be recycled in the whole system without wasting heat energy and without an additional heating device, and can also be used as a heating source of the alkali liquor, so that the layout of the whole system is simpler.

Description

Synthetic ammonia coupling water electrolysis hydrogen production system

Technical Field

The invention relates to the technical field of hydrogen production, in particular to a system for producing hydrogen by coupling synthetic ammonia and electrolyzing water.

Background

The current industrial synthesis of ammonia adopts the Haber-Bosch method to synthesize N ₂ And H ₂ Introducing into a high-temperature and high-pressure reactor (450-500 ℃ and 20-30 MPa) to perform catalytic addition reaction to prepare NH 3. In the traditional process flow, H2 is prepared by coupling catalytic gasification/reforming of fossil fuel with water-gas shift reaction, and then CO2 discharged in the process is subjected to centralized capture treatment. Therefore, the industrial synthesis of ammonia has the problems of high energy consumption, high carbon emission and the like. Meanwhile, a large amount of heat energy can be released in the reaction of the synthetic ammonia, and the traditional synthetic ammonia process (the synthetic ammonia process and the reaction heat recovery process are respectively completed in an ammonia synthesis tower and a waste heat boiler, the number of equipment is large, and the system is complex), so that the development of an efficient and clean industrial synthetic ammonia technical route (for example, green hydrogen obtained by a renewable energy water electrolysis hydrogen production technology is used as a hydrogen source of the synthetic ammonia) has great strategic significance for the sustainable development of China.

At present, the hydrogen production technology by water electrolysis capable of realizing large-scale renewable energy consumption in China only comprises the alkaline water electrolysis technology. Alkaline cells tend to operate at steady power in traditional application scenarios, while for unsteady power input from fluctuating renewable energy sources, their system management suffers from a number of problems, of which heat management is a key one.

Thermal management has a great impact on the efficiency and safety of alkaline hydrogen production: on one hand, the alkaline electrolytic hydrogen production reaction has faster reaction kinetics and lower reaction chamber voltage at higher temperature, which is beneficial to reducing the power consumption in the hydrogen production process and reducing the cost. On the other hand, the electrolytic cell continuously generates heat in the working process, if the heat is continuously accumulated, the temperature is overhigh, the damage to the electrode and the membrane material of the electrolytic cell is easily caused, the reduction of the electrolytic performance is caused, and the mixing and explosion of hydrogen and oxygen are seriously caused. The heat dissipated by the alkaline electrolytic cell also causes the reduction of energy conversion efficiency, resulting in the increase of the overall hydrogen production cost by electrolysis. Therefore, the realization of precise temperature control through heat management is of great significance to the efficient and safe operation of the alkaline electrolysis cell.

The conventional alkaline electrolytic cell generally increases the temperature of the alkaline electrolytic cell in the starting stage through the heat dissipation of the electrolytic reaction, and the process is very slow, so that the alkaline electrolytic cell works in a low-temperature state for a long time, and high energy consumption and low efficiency are caused. Therefore, in order to overcome the defects of the prior art, a new technical solution needs to be provided.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide a synthetic ammonia coupling water electrolysis hydrogen production system, which realizes the high-efficiency heat management of a synthetic ammonia system and water electrolysis hydrogen production, and maintains the optimal temperature interval of an alkaline electrolytic cell under different operating conditions, especially under the condition of the fluctuation input of a renewable energy power supply, so as to maintain the high energy conversion efficiency; meanwhile, green hydrogen prepared by the water electrolysis hydrogen production system is fully utilized as a hydrogen source of synthetic ammonia, and the problem of environmental pollution of the traditional industrial synthetic ammonia is also solved.

In order to achieve the above object, the present application provides a system for producing hydrogen by coupling synthesis ammonia with electrolyzed water, comprising:

a renewable energy source;

the water electrolysis hydrogen production system is connected with the renewable energy power supply so as to produce hydrogen and oxygen by utilizing the renewable energy power supply through electrolysis; the system for producing hydrogen by electrolyzing water comprises at least one gas-liquid separator and at least one alkaline electrolytic cell group, wherein each alkaline electrolytic cell group comprises at least one alkaline electrolytic cell; the alkaline electrolytic tank is connected with the gas-liquid separator;

the synthetic ammonia system comprises an ammonia synthesis tower, wherein the hydrogen inlet end of the ammonia synthesis tower is connected with the hydrogen outlet end of the water electrolysis hydrogen production system;

the heat exchanger is respectively connected with the water electrolysis hydrogen production system and the synthetic ammonia system and is used for collecting coolant absorbed by the water electrolysis hydrogen production system and the synthetic ammonia system; the heat exchanger is also connected with the alkaline electrolytic cell group and is used for heating or preserving heat of the alkali liquor in the alkaline electrolytic cell by utilizing the heat energy in the coolant after absorbing heat; and the number of the first and second groups,

the heat management control module is respectively connected with the heat exchanger and the alkaline electrolytic cell group; the heat management control module distributes the group number or the number of the alkaline electrolysis cells which can be heated according to the heat quantity of the coolant absorbing heat in the heat exchanger.

Optionally, in the system for producing hydrogen by coupling electrolyzed water with synthetic ammonia, the coolant in the system for producing hydrogen by electrolyzed water and the coolant in the system for producing hydrogen by synthetic ammonia are the same or different in type.

Optionally, in the system for producing hydrogen by coupling synthesis ammonia with electrolyzed water, the system for producing hydrogen by electrolyzed water further comprises a purification device and a hydrogen storage tank, and the gas-liquid separator, the purification device and the hydrogen storage tank are sequentially connected; wherein, the hydrogen outlet of the hydrogen storage tank and the hydrogen outlet of the purification equipment are both connected with the ammonia synthesis tower.

Optionally, in the system for producing hydrogen by coupling synthetic ammonia and electrolyzing water, the system for producing hydrogen by electrolyzing water further comprises a valve, the valve is arranged on a connecting pipeline between the heat exchanger and the alkaline electrolytic cell, the valve is used for controlling heat flowing into the alkaline electrolytic cell, the valve is connected with the thermal management control module, and the thermal management control module controls the start-stop state and the opening degree of the valve.

Optionally, the system for producing hydrogen by coupling electrolysis of water with synthetic ammonia further comprises a plurality of temperature sensors, one temperature sensor is arranged in each alkaline electrolysis cell and each heat exchanger, and the temperature sensors are used for detecting the temperature in the alkaline electrolysis cell and the temperature in the heat exchanger; and the temperature sensor is connected with the thermal management control module and feeds back the temperature in the alkaline electrolytic cell and the heat exchanger to the thermal management control module.

Optionally, in the system for producing hydrogen by coupling electrolyzed water with synthetic ammonia, when the number of the alkaline electrolytic cell groups in the system for producing hydrogen by electrolyzed water is at least two, the power of all alkaline electrolytic cells in each alkaline electrolytic cell group is the same, and the power of the alkaline electrolytic cells between each two alkaline electrolytic cell groups is different.

Optionally, in the system for producing hydrogen by coupling synthetic ammonia and electrolyzing water, the renewable energy power source is generated by a renewable energy power generation system, and the renewable energy power generation system is one or more of a wind power generation system, a solar power generation system, a hydroelectric power generation system, a geothermal power generation system, a tidal power generation system, or a wave power generation system.

Compared with the prior art, the synthetic ammonia coupling electrolyzed water hydrogen production system is formed by coupling a synthetic ammonia system into an electrolyzed water hydrogen production system, a heat exchanger is arranged in the system, the heat exchanger is respectively connected with the synthetic ammonia system and the electrolyzed water hydrogen production system and collects the coolant after heat absorption in the synthetic ammonia system and the electrolyzed water hydrogen production system, before starting the alkaline electrolytic cell, the coolant after heat absorption is utilized to preheat the alkali liquor in the alkaline electrolytic cell, the alkali liquor heating process before starting the alkaline electrolytic cell is reduced, the starting time is greatly shortened, the alkaline electrolytic cell is quickly started, the energy consumption is reduced, the fluctuation of a renewable energy power supply can be better adapted, the high energy conversion efficiency is kept, and the overall energy efficiency is improved. Furthermore, the coolant after absorbing heat can play a cooling role in the process steps needing cooling in the synthetic ammonia coupling electrolyzed water hydrogen production system after being cooled by low-temperature alkali liquor, so that the coolant can be recycled in the whole system and can also be used as a heating source of the alkali liquor under the conditions of no waste of heat energy and no need of an additional heating device, and the layout of the whole system is simpler and more efficient.

Drawings

FIG. 1 is a schematic diagram of a system for producing hydrogen by coupling synthesis ammonia with electrolysis water provided by an embodiment of the present application;

FIG. 2 is a flow chart of a method for producing hydrogen by coupling synthesis ammonia with electrolysis water provided by an embodiment of the application;

FIG. 3 is a flow chart of another method for producing hydrogen by coupling synthesis ammonia and electrolyzing water provided by the embodiment of the application;

FIG. 4 is a flow chart of a method for preheating lye in an alkaline electrolytic cell by using a coolant after absorbing heat according to an embodiment of the present application;

FIG. 5 is a flow chart of a method for thermal management of a system for hydrogen production by water electrolysis coupled with synthesis ammonia according to an embodiment of the present application;

FIG. 6 is a flow chart of another method for producing hydrogen by coupling synthesis ammonia with electrolysis water provided by the embodiments of the present application;

fig. 7 is a flow chart of another method for thermal management of a system for producing hydrogen by coupling electrolysis with synthetic ammonia according to an embodiment of the present application.

Wherein the reference numerals of figure 1 are as follows:

10-a water electrolysis hydrogen production system; 11-alkaline electrolysis cell; 12-a gas-liquid separator; 13-purification equipment; 14-a hydrogen storage tank; 20-a synthetic ammonia system; 21-a hydrogen source device; a 22-nitrogen source device; 23-an ammonia synthesis column; 30-a renewable energy source; 40-a heat exchanger; 50-a valve; 60-pipeline.

Detailed Description

In order to make the objects, advantages and features of the present invention clearer, the hydrogen production system by coupling the synthetic ammonia with the electrolyzed water provided by the present invention will be described in further detail below with reference to the accompanying drawings 1 to 7. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is provided for the purpose of facilitating and clearly illustrating embodiments of the present invention.

In order to facilitate an understanding of the invention, the invention is described in more detail below with reference to the accompanying drawings and specific examples. It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may be present. The terms "vertical," "horizontal," "left," "right," "inner," "outer," and the like as used herein are for descriptive purposes only. In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating relative importance or as implicitly indicating the number of technical features indicated. Thus, unless otherwise specified, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; "plurality" means two or more. The terms "comprises" and "comprising," and any variations thereof, are intended to cover a non-exclusive inclusion, such that one or more other features, integers, steps, operations, elements, components, and/or combinations thereof may be present or added.

Furthermore, unless expressly stated or limited otherwise, the terms "mounted," "connected," and "coupled" are to be construed broadly and encompass, for example, both fixed and removable coupling as well as integral coupling; can be mechanically or electrically connected; either directly or indirectly through intervening media, or through both elements. All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Furthermore, the technical features mentioned in the different embodiments of the invention described below can be combined with each other as long as they do not conflict with each other.

Fig. 1 is a schematic diagram of a system for producing hydrogen by water electrolysis coupled with synthetic ammonia according to an embodiment of the present application, wherein the direction of an arrow refers to the direction of coolant and hydrogen after heat absorption in the system for producing hydrogen by water electrolysis coupled with synthetic ammonia.

Referring to fig. 1, the present application provides a system for producing hydrogen by coupling synthesis ammonia with electrolysis water, comprising: renewable energy source 30, water electrolysis hydrogen production system 10, ammonia synthesis system 20, heat exchanger 40, and thermal management control module (not shown in the figures). The water electrolysis hydrogen production system 10 is connected with the renewable energy power supply 30 to electrolyze water by using the renewable energy power supply 30 to produce hydrogen and oxygen. The hydrogen produced by the water electrolysis hydrogen production system 10 can be stored, or can be transported to the hydrogen source device 21 in the ammonia synthesis system 20 to be used as a raw material for ammonia synthesis reaction. The water electrolysis hydrogen production system 10 comprises at least one set of gas-liquid separator 12 and at least one set of alkaline electrolytic cell group, wherein each set of alkaline electrolytic cell group comprises at least one alkaline electrolytic cell 11; the alkaline electrolytic bath 11 is connected to the gas-liquid separator 12. The ammonia synthesis system 20 comprises an ammonia synthesis tower 23, and the hydrogen inlet end of the ammonia synthesis tower 23 is connected with the hydrogen outlet end of the water electrolysis hydrogen production system 10.

The heat exchanger 40 is respectively connected with the hydrogen production system by water electrolysis 10 and the synthetic ammonia system 20, and is used for collecting the coolant absorbed by the hydrogen production system by water electrolysis 10 and the synthetic ammonia system 20. The heat exchanger 40 is further connected to the alkaline electrolytic cell bank, and heats or preserves heat of the alkaline solution in the alkaline electrolytic cell 11 by using heat energy in the coolant after absorbing heat.

The heat management control module is respectively connected with the heat exchanger 40 and the alkaline electrolytic cell group. The thermal management control module distributes the number of groups or number of the alkaline electrolytic cells 11 that can be heated according to the heat of the coolant that absorbs heat in the heat exchanger 40.

The synthetic ammonia coupling water electrolysis hydrogen production system is formed by coupling a synthetic ammonia system 20 into a water electrolysis hydrogen production system 10, and a heat exchanger 40 is arranged in the system, wherein the heat exchanger 40 is respectively connected with the synthetic ammonia system 20 and the water electrolysis hydrogen production system 10. And collecting the coolant after absorbing heat in the ammonia synthesis system 20 and the electrolyzed water hydrogen production system 10, and before starting the alkaline electrolytic cell 11, preheating the alkaline solution in the alkaline electrolytic cell 11 by using the coolant after absorbing heat, so that the temperature rise process of the alkaline solution before starting the alkaline electrolytic cell 11 is reduced, and the starting time of the alkaline electrolytic cell 11 is greatly shortened, thereby realizing the quick starting of the alkaline electrolytic cell 11, reducing the energy consumption, better adapting to the fluctuation of the renewable energy power supply 30, keeping the high energy conversion efficiency, and improving the overall energy efficiency. Furthermore, the coolant after heat absorption can play a cooling role in the process steps needing cooling in the synthetic ammonia coupling electrolyzed water hydrogen production system after being cooled by the low-temperature alkali liquor, so that the coolant can be recycled in the whole system and can also be used as a heating source of the alkali liquor under the conditions of no waste of heat energy and no need of an additional heating device, and the layout of the whole system is simpler and more efficient.

Specifically, the heat exchanger 40 is connected to the gas-liquid separator 12 in the system 10 for producing hydrogen from electrolyzed water. The heat exchanger 40 is connected to the ammonia converter in the ammonia-hydrogen synthesis system 20.

Wherein, the coolant in the hydrogen production system by electrolyzing water 10 and the coolant in the ammonia synthesis system 20 are the same or different in type. When the coolant in the system for producing hydrogen by electrolyzing water 10 and the coolant in the system for synthesizing ammonia 20 are the same in type, the system for producing hydrogen by electrolyzing water coupled with synthesizing ammonia only needs one kind of cooling source, and the heat exchanger 40 only needs one containing area to contain the coolant after absorbing heat. When the coolant in the hydrogen production system by water electrolysis 10 and the coolant in the ammonia synthesis system 20 are different in type, the hydrogen production system by water electrolysis coupled with ammonia synthesis has two different cooling sources, and then the heat exchanger 40 needs to have two independent accommodating areas to accommodate two different endothermic coolants respectively.

Referring to fig. 1, the system 10 for producing hydrogen by electrolyzing water further includes a purification device 13 and a hydrogen storage tank 14, and the gas-liquid separator 12, the purification device 13 and the hydrogen storage tank 14 are connected in sequence. Wherein, the hydrogen outlet of the hydrogen storage tank 14 and the hydrogen outlet of the purification device 13 are both connected with the ammonia synthesis tower 23. That is, in the case that the renewable energy source 30 is sufficient, the hydrogen produced by the alkaline electrolyzer 11 is purified by the purification device 13 and then directly supplied to the ammonia synthesis system 20 as the hydrogen source 21 of the ammonia synthesis, so that the hydrogen source 21 does not need to be further purified in the ammonia synthesis system 20, thereby saving the process steps in the ammonia synthesis system 20. The hydrogen gas produced by the system is stored in the hydrogen storage tank 14, and when the renewable energy power source 30 is in short, the hydrogen gas in the hydrogen storage tank 14 can be delivered to the hydrogen source device 21 in the synthetic ammonia system 20 as a backup hydrogen source 21 in the synthetic ammonia reaction.

With continued reference to fig. 1, in one embodiment, the system 10 for producing hydrogen by electrolyzing water further includes a valve 50, the valve 50 is disposed on a connecting pipe 60 connecting the heat exchanger 40 and the alkaline electrolytic cell 11, the valve 50 is used for controlling heat flowing into the alkaline electrolytic cell 11, and the valve 50 is connected to the thermal management control module, and the thermal management control module controls the on-off state and the opening degree of the valve 50. The intelligent distribution of the heat energy contained in the heat-absorbed coolant in the thermal management control module is facilitated.

Further, the system for producing hydrogen by coupling and electrolyzing water in synthetic ammonia further comprises a plurality of temperature sensors (not shown in the figure), wherein one temperature sensor is arranged in each of the alkaline electrolysis cell 11 and the heat exchanger 40, and the temperature sensors are used for detecting the temperature in the alkaline electrolysis cell 11 and the temperature in the heat exchanger 40. And the temperature sensor is connected with the thermal management control module and feeds back the temperature in the alkaline electrolytic cell 11 and the heat exchanger 40 to the thermal management control module. The thermal management control module can calculate the total heat quantity of the coolant after absorbing heat in the heat exchanger 40 according to the temperature of the coolant after absorbing heat in the coolant, calculate the heat quantity required when the alkali liquor in each alkaline electrolytic cell 11 is preheated to a preset temperature according to the temperature of the alkali liquor in each alkaline electrolytic cell 11, and then match the total heat quantity in the heat exchanger 40 with the number of the alkaline electrolytic cells 11 needing to preheat the alkali liquor.

In yet another embodiment, when there are at least two groups of alkaline cells in the system 10, the power of all alkaline cells 11 in each group of alkaline cells is the same, and the power of the alkaline cells 11 between each two groups of alkaline cells is different. In the setting of the alkaline electrolytic cell groups with different powers, the number of the alkaline electrolytic cells 11 can be intelligently started according to the fluctuation of the input power of the renewable energy power supply 30, and the total heat energy in the heat exchanger 40 can be flexibly and intelligently matched with the number of the alkaline electrolytic cells 11 needing to preheat the alkali liquor. The adaptability of the synthesis ammonia coupling water electrolysis hydrogen production system to wider power fluctuation is improved, and the starting speed and flexibility of the synthesis ammonia coupling water electrolysis hydrogen production system are improved.

Wherein the renewable energy power source 30 is generated by a renewable energy power generation system, and the renewable energy power generation system is one or more of a wind power generation system, a solar power generation system, a hydroelectric power generation system, a geothermal power generation system, a tidal power generation system, or a wave power generation system. The green hydrogen can be produced by green electricity. Of course, the renewable energy power source can be directly used for water electrolysis hydrogen production after being generated by the renewable energy power generation system, or can be used for water electrolysis hydrogen production after being generated by the renewable energy power generation system and being merged into a power grid.

Referring to fig. 2 in conjunction with fig. 1. On the other hand, the application also provides a hydrogen production method by coupling synthetic ammonia and electrolyzing water, and provides the hydrogen production system by coupling synthetic ammonia and electrolyzing water, which comprises the following steps:

executing S110: the ammonia synthesis system 20 uses hydrogen and nitrogen as raw materials, and the hydrogen and the nitrogen are mixed to carry out ammonia synthesis reaction. The hydrogen gas may be the hydrogen gas purified by the purification device 13 and then enter the hydrogen source device 21, or the hydrogen gas stored in the hydrogen storage tank 14 and then enter the hydrogen source device 21. Specifically, before the system for producing hydrogen by coupling and electrolyzing water in the synthetic ammonia is never started, the hydrogen supplied to the hydrogen source device 21 is purified hydrogen provided from the outside. After the synthesis ammonia coupling water electrolysis hydrogen production system is started, the hydrogen supplied to the hydrogen source device 21 is the hydrogen stored in the hydrogen storage tank 14 after the last work of the water electrolysis hydrogen production system 10 is finished. In the working process of the system for producing hydrogen by coupling and electrolyzing water in the synthesis ammonia, the hydrogen purified by the purifying device 13 is directly supplied to the hydrogen source device 21. The synthetic ammonia system further comprises a nitrogen source device 22, and nitrogen enters the nitrogen source device 22 after purification treatment to serve as a nitrogen source for synthetic ammonia reaction. Thereby realizing the preparation of green ammonia by green hydrogen.

Executing S120: the coolant absorbs at least part of the heat released by the synthesis ammonia reaction. When only the synthetic ammonia system 20 is started, the coolant only needs to cool the synthetic ammonia system 20 to absorb the heat released by the synthetic ammonia reaction.

Execution of S130: the heat exchanger 40 collects the coolant after absorbing heat in the ammonia synthesis system 20.

Execution of S140: the heat energy of the coolant absorbing heat in the heat exchanger 40 is used for preheating the alkali liquor in the alkaline electrolytic cell 11. The conventional alkaline electrolytic cell 11 has the technical characteristics that the temperature of the alkaline solution is slowly increased during cold start, and the alkaline solution needs a long time to reach the working temperature. Sometimes, in order to start quickly, there is also a technical scheme of electrically heating the alkali liquor, however, a large amount of electric power is consumed, and the comprehensive energy efficiency is poor. In all the embodiments, the coolant after absorbing heat in the heat exchanger 40 is used as a heating source for preheating the alkali liquor in the alkaline electrolytic cell 11, so that the power can be saved, and the alkaline electrolytic cell 11 can be started quickly.

Executing S150: starting the alkaline electrolytic tank 11 with preheated alkaline liquid to carry out electrolytic hydrogen production. The produced hydrogen gas is purified and then directly supplied to the ammonia synthesis system 20 and/or stored in the hydrogen storage tank 14. That is, when the amount of hydrogen produced by the water electrolysis hydrogen production system 10 is greater than the required amount of hydrogen in the ammonia synthesis system 20 during the peak of renewable energy, the produced hydrogen is stored in the hydrogen storage tank 14 as a backup hydrogen source for the ammonia synthesis system 20.

The heat generated in the ammonia synthesis system 20 is absorbed by the coolant, and then the coolant after heat absorption is used as a heat transfer medium to preheat the alkali liquor in the alkaline electrolytic cell 11 to be started. The method makes full use of a large amount of heat energy released in the ammonia synthesis process, improves the utilization rate of the heat energy and reduces the energy consumption. Meanwhile, the alkaline electrolytic cell 11 does not need to wait for the renewable energy power supply 30 to heat the alkali liquor in the alkaline electrolytic cell 11 to the working temperature and then produce hydrogen, so that the alkaline electrolytic cell 11 can be started quickly, and the hydrogen production efficiency of the alkaline electrolytic cell 11 is improved when the renewable energy power supply 30 outputs a certain power.

Referring to fig. 3, in conjunction with fig. 1-2. In one embodiment, in performing S150: after the step of starting the alkaline electrolytic bath 11 with preheated alkaline liquor to perform electrolytic hydrogen production, the method also comprises the following steps:

executing S160: the coolant absorbs at least part of the heat of the water electrolysis hydrogen production system 10;

executing S170: the heat exchanger 40 collects the coolant absorbed in the water electrolysis hydrogen production system 10. That is, after the hydrogen production system 10 starts producing hydrogen, the coolant in the hydrogen production system 10 is collected by the heat exchanger 40 after absorbing the preheating of the hydrogen production system 10.

Executing S180: the heat energy of the coolant absorbing heat in the heat exchanger 40 is used to preheat the alkali liquor in the other non-activated alkaline electrolytic cells 11.

Referring to fig. 4, in conjunction with fig. 1. Wherein, executing S140: the method for preheating the alkali liquor in the alkaline electrolytic cell 11 by utilizing the heat energy of the coolant after absorbing heat in the heat exchanger 40 comprises the following steps:

execution of S141: real-time heat information is obtained for the heat-absorbed coolant in the heat exchanger 40.

Executing S142: and acquiring heat information required when the alkali liquor in each alkaline electrolytic cell 11 needs to be preheated to a preset temperature.

Executing S143: the amount of heat of the coolant having absorbed heat in the heat exchanger 40 that can heat the alkaline electrolytic cell 11 at the same time is counted.

Specifically, the real-time total heat in the heat exchanger 40 is calculated by obtaining the real-time heat information of the coolant absorbing heat in the heat exchanger 40, and the heat required when the alkali liquor in each alkaline electrolytic cell 11 needs to be preheated to the preset temperature is calculated by obtaining the heat information required when the alkali liquor in each alkaline electrolytic cell 11 needs to be preheated to the preset temperature. So that the thermal management control module can match the number of pre-heated alkaline electrolyzers 11 according to the real-time total heat in the heat exchanger 40. Of course, the number of alkaline cells 11 in the matched pre-heating can be combined with the real-time output power of the renewable energy source 30.

Further, when both the ammonia synthesis system 20 and the water electrolysis hydrogen production system 10 are in an operating state, S141: acquiring real-time heat information of the coolant absorbing heat in the heat exchanger 40 may also be performed in S170: the heat exchanger 40 collects the coolant absorbed heat in the water electrolysis hydrogen production system 10.

With reference to fig. 1, the method for producing hydrogen by coupling and electrolyzing water in the synthesis of ammonia further comprises the following steps:

the hydrogen produced by the electrolysis in the alkaline electrolysis cell 11 is supplied to the ammonia synthesis system 20 as the raw material for ammonia synthesis. Therefore, the hydrogen source 21 in the ammonia synthesis process is green hydrogen, the hydrogen source 21 does not need to be purified, the pollution to the environment is reduced compared with the traditional ammonia synthesis process, and the method is beneficial to environmental protection.

Referring to fig. 5, in conjunction with fig. 1. In another aspect, the present application further provides a thermal management method for hydrogen production by coupling synthesis ammonia with electrolyzed water, which provides the above hydrogen production system by coupling synthesis ammonia with electrolyzed water, and the thermal management method for the hydrogen production system by electrolyzed water comprises the following steps:

executing S210: the ammonia synthesis system 20 is started. The ammonia synthesis system 20 begins the ammonia synthesis reaction and releases a large amount of heat.

Executing S220: the endothermic coolant in the ammonia synthesis system 20 is collected. After the synthesis ammonia reaction releases a large amount of heat, the coolant begins to absorb the heat released by the reaction to cool the synthesis ammonia system 20. The coolant after absorbing heat is collected by the heat exchanger 40.

Executing S230: and preheating the alkali liquor in the alkaline electrolytic cell 11 by utilizing the heat energy of the coolant after heat absorption.

Executing S240: and detecting the temperature of the preheated alkali liquor. The temperature of the preheated lye is transmitted to the thermal management control module by a temperature sensor in the alkaline electrolytic cell 11.

Executing S250: judging whether the temperature of the preheated alkali liquor is not lower than the preset temperature, if so, executing S270: starting the alkaline electrolytic cell 11 and preheating the alkali liquor in the alkaline electrolytic cell 11 which is not preheated by using the heat energy of the coolant after heat absorption; if not, executing S230: the heat energy of the coolant after absorbing heat is used for continuously heating the alkali liquor in the alkaline electrolytic tank 11. The thermal management control module compares the temperature of the alkali liquor inside the alkaline electrolytic cell 11 sensed by the temperature sensor with a preset temperature, so as to judge whether the temperature of the preheated alkali liquor is not lower than the preset temperature.

Wherein the preset temperature is 80-95 ℃. For example: 80 ℃, 85 ℃, 90 ℃ and 95 ℃. The start-up time of the alkaline cell 11 is directly related to the temperature of the alkaline liquid. When the temperature of the alkaline electrolytic cell 11 reaches 80-95 ℃, the time of the alkali liquor temperature rise process after the water electrolysis hydrogen production system 10 is powered on can be greatly shortened, so that the starting speed of the alkaline electrolytic cell 11 can be accelerated, and the stability of the alkaline electrolytic cell 11 is also improved.

Referring to fig. 6, in conjunction with fig. 1. Further, in executing S230: before the step of preheating the alkali liquor in the alkaline electrolytic cell 11 by using the heat energy of the coolant after heat absorption, the method further comprises the following steps:

executing S221: acquiring real-time heat information of the coolant after heat absorption;

executing S222: acquiring heat information required when alkali liquor in each alkaline electrolytic cell 11 needs to be preheated to a preset temperature;

executing S223: the amount of heat of the coolant after the heat absorption can be calculated to heat the alkaline electrolytic cell 11 at the same time.

Therefore, the waste heat generated by the operation of the ammonia synthesis system 20 and the water electrolysis hydrogen production system 10 can be fully utilized, and the overall energy efficiency is improved.

Referring to fig. 7 in conjunction with fig. 1. Wherein, in executing S260: after the step of starting the alkaline electrolytic cell 11, the method further comprises the steps of:

executing S270: collecting the coolant absorbed by the water electrolysis hydrogen production system 10;

executing S280: the heat energy of the coolant absorbing heat in the heat exchanger 40 is used to preheat the alkali liquor in the other non-activated alkaline electrolytic cells 11.

It can be seen that the number of alkaline cells 11 that are rapidly activated is based on the precise control of the thermal energy in the heat exchanger 40 by the thermal management control module, which is advantageous in increasing the achievable upper temperature limit and thus maintaining high energy conversion efficiency.

The above description is only for the purpose of describing the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention, and any variations and modifications made by those skilled in the art based on the above disclosure are within the scope of the appended claims.

Claims (7)

1. A system for producing hydrogen by coupling synthesis ammonia and electrolyzing water is characterized by comprising:

a renewable energy source;

the water electrolysis hydrogen production system is connected with the renewable energy power supply so as to produce hydrogen and oxygen by utilizing the renewable energy power supply through electrolysis; the system for producing hydrogen by electrolyzing water comprises at least one gas-liquid separator and at least one alkaline electrolytic cell group, wherein each alkaline electrolytic cell group comprises at least one alkaline electrolytic cell; the alkaline electrolytic tank is connected with the gas-liquid separator;

the synthetic ammonia system comprises an ammonia synthesis tower, wherein the hydrogen inlet end of the ammonia synthesis tower is connected with the hydrogen outlet end of the water electrolysis hydrogen production system;

the heat exchanger is respectively connected with the water electrolysis hydrogen production system and the synthetic ammonia system and is used for collecting coolant absorbed by the water electrolysis hydrogen production system and the synthetic ammonia system; the heat exchanger is also connected with the alkaline electrolytic cell group and is used for heating or preserving heat of the alkali liquor in the alkaline electrolytic cell by utilizing the heat energy in the coolant after absorbing heat; and (c) a second step of,

the heat management control module is respectively connected with the heat exchanger and the alkaline electrolytic cell group; the heat management control module distributes the number of groups or the number of the alkaline electrolysis cells which can be heated according to the heat quantity of the coolant absorbing heat in the heat exchanger.

2. The system for producing hydrogen by coupling electrolysis of water according to claim 1, wherein the coolant in the system for producing hydrogen by electrolysis of water and the coolant in the system for producing ammonia by synthesis are the same or different in kind.

3. The system for producing hydrogen by electrolyzing water through coupling synthesis ammonia according to claim 1, further comprising a purification device and a hydrogen storage tank, wherein the gas-liquid separator, the purification device and the hydrogen storage tank are connected in sequence; wherein, the hydrogen outlet of the hydrogen storage tank and the hydrogen outlet of the purification equipment are both connected with the ammonia converter.

4. A system for producing hydrogen by coupling electrolyzed water according to claim 2, further comprising a valve, wherein the valve is arranged on a connecting pipeline between the heat exchanger and the alkaline electrolytic tank, the valve is used for controlling the heat flowing into the alkaline electrolytic tank, and is connected with the thermal management control module, and the thermal management control module controls the start-stop state and the opening degree of the valve.

5. The system for producing hydrogen by coupling electrolysis water with synthetic ammonia according to claim 2, further comprising a plurality of temperature sensors, one temperature sensor being disposed in each of the alkaline electrolysis cell and the heat exchanger, the temperature sensors being configured to detect the temperature in the alkaline electrolysis cell and the heat exchanger; and the temperature sensor is connected with the thermal management control module and feeds back the temperature in the alkaline electrolytic cell and the heat exchanger to the thermal management control module.

6. A system for producing hydrogen by coupling electrolysis of water according to claim 1, wherein when there are at least two groups of alkaline cells in the system, the power of all alkaline cells in each group is the same, and the power of alkaline cells between each group is different.

7. The system for producing hydrogen by coupling electrolysis of water according to claim 1, wherein the renewable energy power source is generated by a renewable energy power generation system that is one or more of a wind power generation system, a solar power generation system, a hydro power generation system, a geothermal power generation system, a tidal power generation system, or a wave power generation system.

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