Ammonia hydrogen production system in thermal power plant and working method

Abstract

The invention discloses an ammonia hydrogen production system in a thermal power plant and a working method. The system comprises a hydrogen production device, an air separation nitrogen production device and the like, the hydrogen production device is respectively connected with the oxygen storage tank and the hydrogen storage tank, the oxygen storage tank is respectively connected with other aerobic users and the gas mixer, the hydrogen storage tank is respectively connected with the gas mixer and the ammonia production device, the gas mixer is connected with the thermal power plant, and the air separation nitrogen production device is sequentially connected with the nitrogen storage tank and the ammonia production device. The ammonia production device is connected with the thermal power plant, the thermal power plant is respectively connected with the gas mixer and the step-down inverter, and the step-down inverter is connected with the hydrogen production device through a low-voltage direct-current circuit. The method comprises an electrolysis hydrogen and oxygen production part, a boiler ignition combustion-supporting part and an ammonia production denitration part, hydrogen is produced by using redundant electric power in a deep peak regulation stage of a thermal power plant unit through an alkaline electrolysis water process, and ammonia gas is synthesized by using nitrogen extracted by an air separation nitrogen production device and the produced hydrogen.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen and ammonia production from thermal power generation, and particularly to a hydrogen and ammonia production system and working method in a thermal power plant. Background Art

[0002] Promoting clean energy faces numerous challenges, such as high technical costs, energy storage difficulties, supply instability, and the complexity of grid connection. On the other hand, due to the demand for stable power supply, thermal power generation still occupies an irreplaceable position in the domestic power supply. With the changes in the power market demand and the increasing requirements for the penetration rate of renewable energy, power plants are facing the dual challenges of improving grid connection flexibility and broadening the operating load range.

[0003] As a zero-carbon energy conversion and storage solution, hydrogen production and energy storage technology can not only convert excess electric energy into high-value hydrogen energy through electrolytic water hydrogen production technology, but also convert it back into stable electric energy through hydrogen fuel cells, providing a new load regulation tool for the power system. However, the large space required for hydrogen storage and the long-distance transportation that must be carried out in the absence of nearby hydrogen energy users have greatly limited its wide application, especially the transportation cost has become the main obstacle in areas without nearby consumers.

[0004] In the daily operation of thermal power plants, the boiler burners relying on fossil fuels inevitably produce a large amount of carbon emissions and other pollutants during ignition and combustion support processes, thus exacerbating environmental pollution problems. In addition, to meet environmental protection regulations, urea purchased externally is often used in the process of denitrifying boiler flue gas, which makes the power plant subject to the price fluctuations of the urea market and also increases carbon emissions during the operation process, having an adverse impact on the environmental protection performance and economic benefits of the power plant. Summary of the Invention

[0005] To overcome the above-mentioned disadvantages of the prior art, the present invention proposes a hydrogen and ammonia production system and working method in a thermal power plant. The thermal power plant deploys a hydrogen and ammonia production system, and through the alkaline electrolytic water process, hydrogen is produced using redundant power during the low-demand period of electricity. The produced hydrogen is not only used for ignition and combustion support of the boiler, but also reacts with nitrogen extracted by an air separation device to synthesize ammonia, which is used to replace the externally purchased urea for boiler denitrification, effectively reducing the operating cost and environmental impact. This system realizes the self-sufficiency of the thermal power plant in chemical supply, and at the same time significantly reduces the minimum technical output of the unit and the grid-connected power of the thermal power generation unit, thus creating more space for the grid to accommodate new energy such as wind energy and solar energy, providing a continuous and practical energy solution.

[0006] To achieve the above object, the present invention adopts the following technical solutions: A hydrogen and ammonia production system in a thermal power plant, comprising a hydrogen production device, an air separation nitrogen production device, a thermal power plant, an ammonia production device, an oxygen storage tank, a hydrogen storage tank, a nitrogen storage tank, a gas mixer and a step-down and inversion device; The hydrogen production device is respectively connected to the oxygen storage tank and the hydrogen storage tank. The oxygen storage tank is respectively connected to other oxygen-requiring users and the gas mixer. The hydrogen storage tank is respectively connected to the gas mixer and the ammonia production device. The gas mixer is connected to the thermal power plant. The air separation nitrogen production device is sequentially connected to the nitrogen storage tank and the ammonia production device. The ammonia production device is connected to the thermal power plant. The thermal power plant is respectively connected to the gas mixer and the step-down and inversion device. The step-down and inversion device is connected to the hydrogen production device through a low-voltage direct current line.

[0007] A further improvement of the present invention lies in that the hydrogen production device includes a water supply tank, an alkaline electrolyte tank, an alkaline electrolytic cell, a separation, cooling and drying device and a low-voltage direct current line. The low-voltage direct current line is connected to the alkaline electrolytic cell. The alkaline electrolytic cell is respectively connected to the water supply tank, the alkaline electrolyte tank and the separation, cooling and drying device. The separation, cooling and drying device is respectively connected to the oxygen storage tank and the hydrogen storage tank.

[0008] A further improvement of the present invention lies in that the thermal power plant includes a boiler burner, a power generation system of the power plant, an air preheater and a denitration device; the boiler burner, the power generation system of the power plant, the air preheater and the denitration device are arranged in the thermal power plant. The gas mixer is connected to the boiler burner. The air preheater is connected to the gas mixer. The denitration device is connected to the ammonia production device. The power generation system of the power plant is connected to the step-down and inversion device.

[0009] A further improvement of the present invention lies in that the ammonia production device includes a hydrogen-nitrogen mixing device, a hydrogen-nitrogen reaction device, a gas separator, an ammonia storage tank, a hydrogen return pipeline and a nitrogen return pipeline; the hydrogen-nitrogen mixing device is connected to the hydrogen storage tank, the nitrogen storage tank and the hydrogen-nitrogen reaction device. The hydrogen-nitrogen reaction device is sequentially connected to the gas separator, the ammonia storage tank and the thermal power plant. The gas separator is connected to the hydrogen-nitrogen reaction device through the hydrogen return pipeline and the nitrogen return pipeline.

[0010] A working method of a hydrogen and ammonia production system in a thermal power plant, comprising an electrolytic hydrogen and oxygen production part, a boiler ignition and combustion support part and an ammonia production and denitration part. Hydrogen is produced by an alkaline electrolytic water process using the redundant power in the deep peak shaving stage of the thermal power plant unit. The produced hydrogen and oxygen are mixed with air and used for the ignition or combustion support of the boiler burner. At the same time, nitrogen extracted by the air separation nitrogen production device is used to synthesize ammonia with the produced hydrogen.

[0011] A further improvement of the present invention lies in the electrolytic hydrogen and oxygen production part. During the deep peak shaving stage of the thermal power unit, when the power generated by the unit exceeds the demand, the redundant power generated by the thermal power plant enters the step-down and inversion device, where it is stepped down and converted into direct current. Then it enters the alkaline electrolyzer through a low-voltage direct current line for electrolysis. The water supply tank and the alkaline electrolyte tank timely supplement water and alkaline electrolyte according to the electrolysis situation of the alkaline electrolyzer. The electrolysis products are separated, cooled, and dried in the separation, cooling, and drying device, and then the oxygen and hydrogen are respectively stored in the oxygen storage tank and the hydrogen storage tank.

[0012] A further improvement of the present invention lies in that the produced oxygen is used for the combustion support of the power plant boiler and other oxygen-requiring users.

[0013] A further improvement of the present invention lies in that the produced hydrogen is used to replace the fuel oil for combustion support in the power plant and to produce ammonia in the power plant.

[0014] A further improvement of the present invention lies in the boiler ignition and combustion support part. When the thermal power plant needs to ignite or support combustion, hydrogen enters the gas mixer from the hydrogen storage tank, and at the same time, oxygen enters the gas mixer from the oxygen storage tank. Air passes through the air preheater in the thermal power plant and enters the gas mixer. The flow rates of hydrogen, oxygen, and air are controlled and adjusted according to the boiler operation requirements and then enter the boiler burner.

[0015] A further improvement of the present invention lies in the ammonia production and denitrification part. Air is compressed, condensed, and filtered in the air separation and nitrogen production device, and then nitrogen is extracted and stored in the nitrogen storage tank using fractional distillation technology. Hydrogen in the hydrogen storage tank enters the hydrogen-nitrogen mixing device, and nitrogen in the nitrogen storage tank enters the hydrogen-nitrogen mixing device. Hydrogen and nitrogen are mixed in the hydrogen-nitrogen mixing device according to a set ratio and then enter the hydrogen-nitrogen reaction device, where an ammonia synthesis reaction occurs under high temperature and high pressure conditions. The reacted mixed gas enters the gas separator for the separation of ammonia, hydrogen, and nitrogen. The separated hydrogen and nitrogen are respectively returned to the hydrogen-nitrogen reaction device through the hydrogen reflux pipeline and the nitrogen reflux pipeline for reuse, while the separated ammonia enters the ammonia storage tank through a pipeline for storage. When the thermal power plant needs denitrification, ammonia in the ammonia storage tank enters the denitrification device and fully mixes with NOx in the flue gas at the tail of the boiler to undergo a reduction reaction for flue gas denitrification.

[0016] Compared with the prior art, the present invention has at least the following beneficial technical effects: A hydrogen and ammonia production system and working method in a thermal power plant provided by the present invention uses the alkaline electrolysis water process to produce hydrogen in the thermal power plant, effectively absorbing redundant power, avoiding the waste of excess power, and converting it into hydrogen. This not only reduces the grid-connected power of the thermal power unit, thereby reducing the minimum technical output of the unit, but also creates more space for the grid to absorb new energy such as wind energy and solar energy, thus improving the operation efficiency and response flexibility of the power generation system.

[0017] The system implemented in the present invention utilizes the hydrogen produced in the factory and transports it to the boiler burner for ignition or combustion support, replacing the use of traditional boiler ignition and combustion-supporting fuel oil. This not only reduces the dependence on and consumption of fossil fuels but also helps to reduce carbon emissions and the emissions of other harmful gases, making the boiler combustion process cleaner and more environmentally friendly. In addition, the introduction of hydrogen combustion support ensures that the thermal power unit can operate stably within a wider and more flexible load range, further providing a stable regulation capacity for the grid connection of new energy.

[0018] The system implemented in the present invention is configured with an air separation nitrogen production system, which is used together with hydrogen for ammonia synthesis, replacing the dependence on externally purchased urea and being used in the boiler denitrification process. This not only reduces the purchase and use costs of chemicals but also, due to on-site production, reduces the transportation and storage processes of chemicals, effectively reducing the environmental risks that may be caused by chemical leakage or improper handling. Description of the Drawings

[0019] Figure 1 It is a schematic structural diagram of a hydrogen and ammonia production system within a thermal power plant provided for the implementation of the present invention.

[0020] Figure 2 It is a schematic structural diagram of the hydrogen production device part in a hydrogen and ammonia production system within a thermal power plant provided for the implementation of the present invention.

[0021] Figure 3 It is a schematic structural diagram of the thermal power plant part in a hydrogen and ammonia production system within a thermal power plant provided for the implementation of the present invention.

[0022] Figure 4 It is a schematic structural diagram of the ammonia production device part in a hydrogen and ammonia production system within a thermal power plant provided for the implementation of the present invention.

[0023] Description of the Reference Numerals: Hydrogen production device 1; Air separation nitrogen production device 2; Thermal power plant 3; Ammonia production device 4; Oxygen storage tank 5; Hydrogen storage tank 6; Nitrogen storage tank 7; Gas mixer 8; Step-down and inversion device 9; Other oxygen-requiring users 10; Water supply tank 101; Alkaline electrolyte tank 102; Alkaline electrolytic cell 103; Separation, cooling and drying device 104; Boiler burner 301; Boiler power generation system 302; Air preheater 303; Denitrification device 304; Hydrogen-nitrogen mixing device 401; Hydrogen-nitrogen reaction device 402; Gas separator 403; Ammonia storage tank 404; First oxygen pipeline 111; First hydrogen pipeline 112; High-voltage alternating current line 311; Air delivery pipeline 312; Ammonia pipeline 411; Second oxygen pipeline 511; Second hydrogen pipeline 611; Third hydrogen pipeline 612; Nitrogen pipeline 711; First gas pipeline 811; Low-voltage direct current line 911; Second gas pipeline 4021; Hydrogen return pipeline 4031; Nitrogen return pipeline 4032. Detailed Embodiments

[0024] In the following text, only some exemplary embodiments are briefly described. As those skilled in the art can recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the present invention. Therefore, the accompanying drawings and the description are considered to be exemplary in nature and not restrictive.

[0025] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality of" means two or more unless otherwise specifically defined.

[0026] In the present invention, unless otherwise clearly defined and limited, the terms "mounted", "connected", "coupled", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, an electrical connection, or a communication connection; it can be directly connected, or indirectly connected through an intermediate medium, and can be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] In the present invention, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through additional features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the first feature has a lower horizontal height than the second feature.

[0028] It should also be understood that the terms used in the specification of the present invention are merely for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include the plural forms.

[0029] It should be further understood that the term "and / or" used in the specification of the present invention and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0030] Various structural schematic diagrams according to the disclosed embodiments of the present invention are shown in the accompanying drawings. These figures are not drawn to scale, where for the purpose of clear expression, some details are enlarged and some details may be omitted. The shapes of various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary and may deviate in practice due to manufacturing tolerances or technical limitations. Those skilled in the art can additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0031] Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0032] Embodiment 1 As Figure 1 shown, a hydrogen and ammonia production system within a thermal power plant provided in this embodiment includes a hydrogen production device 1, an air separation nitrogen production device 2, a thermal power plant 3, an ammonia production device 4, an oxygen storage tank 5, a hydrogen storage tank 6, a nitrogen storage tank 7, a gas mixer 8, and a step-down and inversion device 9; the hydrogen production device 1 is respectively connected to the oxygen storage tank 5 and the hydrogen storage tank 6, the oxygen storage tank 5 is respectively connected to other oxygen-requiring users 10 and the gas mixer 8, the hydrogen storage tank 6 is respectively connected to the gas mixer 8 and the ammonia production device 4, the gas mixer 8 is connected to the thermal power plant 3, the air separation nitrogen production device 2 is sequentially connected to the nitrogen storage tank 7 and the ammonia production device 4, the ammonia production device 4 is connected to the thermal power plant 3, the thermal power plant 3 is respectively connected to the gas mixer 8 and the step-down and inversion device 9, and the step-down and inversion device 9 is connected to the hydrogen production device 1 through a low-voltage direct current line 911.

[0033] Embodiment 2 As Figure 1 shown, a hydrogen and ammonia production system within a thermal power plant provided in this embodiment includes a hydrogen production device 1, an air separation nitrogen production device 2, a thermal power plant 3, an ammonia production device 4, an oxygen storage tank 5, a hydrogen storage tank 6, a nitrogen storage tank 7, a gas mixer 8, a step-down and inversion device 9, other oxygen-requiring users 10, a first oxygen pipeline 111, a first hydrogen pipeline 112, a high-voltage alternating current line 311, an air delivery pipeline 312, an ammonia pipeline 411, a second oxygen pipeline 511, a second hydrogen pipeline 611, a third hydrogen pipeline 612, a nitrogen pipeline 711, a first gas pipeline 811, and a low-voltage direct current line 911.

[0034] Among them, the hydrogen production device 1 is connected to the oxygen storage tank 5 through the first oxygen pipeline 111 and to the hydrogen storage tank 6 through the first hydrogen pipeline 112; the oxygen storage tank 5 is connected to other oxygen-requiring users 10 and to the gas mixer 8 through the second oxygen pipeline 511; the hydrogen storage tank 6 is connected to the gas mixer 8 through the second hydrogen pipeline 611 and to the ammonia production device 4 through the third hydrogen pipeline 612; the gas mixer 8 is connected to the thermal power plant 3 through the first gas pipeline 811; the air separation nitrogen production device 2 is successively connected to the nitrogen storage tank 7, the nitrogen pipeline 711, and the ammonia production device 4; the ammonia production device 4 is connected to the thermal power plant 3 through the ammonia pipeline 411; the thermal power plant 3 is connected to the gas mixer 8 through the air delivery pipeline 312 and to the step-down inverter device 9 through the high-voltage alternating current line 311; the step-down inverter device 9 is connected to the hydrogen production device 1 through the low-voltage direct current line 911.

[0035] As Figure 2 shown, the hydrogen production device 1 includes a water supply tank 101, an alkaline electrolyte tank 102, an alkaline electrolytic cell 103, a separation, cooling and drying device 104, a first oxygen pipeline 111, a first hydrogen pipeline 112, and a low-voltage direct current line 911.

[0036] Among them, the low-voltage direct current line 911 is connected to the alkaline electrolytic cell 103, and the alkaline electrolytic cell 103 is respectively connected to the water supply tank 101, the alkaline electrolyte tank 102, and the separation, cooling and drying device 104. The separation, cooling and drying device 104 is respectively connected to the first oxygen pipeline 111 and the first hydrogen pipeline 112.

[0037] As Figure 3 shown, the thermal power plant 3 includes a boiler burner 301, a power plant power generation system 302, an air preheater 303, a denitration device 304, a high-voltage alternating current line 311, an air delivery pipeline 312, an ammonia pipeline 411, and a first gas pipeline 811.

[0038] Among them, the boiler burner 301, the power plant power generation system 302, the air preheater 303, and the denitration device 304 are reasonably arranged in the thermal power plant 3. The first gas pipeline 811 is connected to the boiler burner 301, the air preheater 303 is connected to the air delivery pipeline 312, the denitration device 304 is connected to the ammonia pipeline 411, and the power plant power generation system 302 is connected to the high-voltage alternating current line 311.

[0039] As Figure 4 shown, the ammonia production device 4 includes a hydrogen-nitrogen mixing device 401, a hydrogen-nitrogen reaction device 402, a gas separator 403, an ammonia storage tank 404, an ammonia pipeline 411, a third hydrogen pipeline 612, a nitrogen pipeline 711, a second gas pipeline 4021, a hydrogen return pipeline 4031, and a nitrogen return pipeline 4032.

[0040] Among them, the hydrogen-nitrogen mixing device 401 is connected to the third hydrogen pipeline 612, the nitrogen pipeline 711, and the hydrogen-nitrogen reaction device 402. The hydrogen-nitrogen reaction device 402 is sequentially connected to the second gas pipeline 4021, the gas separator 403, the ammonia storage tank 404, and the ammonia pipeline 411. The gas separator 403 is connected to the hydrogen-nitrogen reaction device 402 through the hydrogen return pipeline 4031 and the nitrogen return pipeline 4032.

[0041] Example 3 As Figure 1 shown, a working method of a hydrogen and ammonia production system in a thermal power plant provided in this embodiment includes an electrolytic hydrogen and oxygen production part, a boiler ignition and combustion support part, and an ammonia production and denitration part. Hydrogen is produced by using the redundant power in the deep peak shaving stage of Unit 3 of the thermal power plant through the alkaline electrolytic water process. The produced hydrogen and oxygen are mixed with air and used for the ignition or combustion support of the boiler burner 301. At the same time, nitrogen gas extracted by the air separation nitrogen production device 2 is used to synthesize ammonia with the produced hydrogen.

[0042] Example 4 In a hydrogen and ammonia production system in a thermal power plant of the present invention, hydrogen is produced by using the redundant power in the deep peak shaving stage of Unit 3 of the thermal power plant through the alkaline electrolytic water process. The produced hydrogen and oxygen are mixed with air and used for the ignition or combustion support of the boiler burner 301. At the same time, nitrogen gas extracted by the air separation nitrogen production device 2 is used to synthesize ammonia with the produced hydrogen, replacing the purchased urea for boiler denitration. This system not only enables the thermal power plant to achieve self-sufficiency in chemical requirements, but also significantly improves energy efficiency and economy. At the same time, it comprehensively utilizes the resources and technologies of the thermal power plant, consumes redundant power during the low power demand period, reduces the grid-connected power of the thermal power generation unit, and creates more space for the grid to absorb new energy such as wind energy and solar energy, thereby improving the operating efficiency and response flexibility of the entire power generation system and effectively supporting the green transformation of the power system. The working method of this system includes an electrolytic hydrogen and oxygen production part, a boiler ignition and combustion support part, and an ammonia production and denitration part.

[0043] For the electrolytic hydrogen and oxygen production part, during the deep peak shaving stage of the thermal power generation unit, when the power generated by the unit exceeds the demand, the redundant power generated by the thermal power plant 3 enters the step-down inverter device 9 through the high-voltage alternating current line 311, completes step-down and is converted into direct current, and enters the alkaline electrolytic cell 103 through the low-voltage direct current line 911 for electrolysis. The water supply tank 101 and the alkaline electrolyte tank 102 timely supplement water and alkaline electrolyte according to the electrolysis situation of the alkaline electrolytic cell 103. The electrolyzed products are separated, cooled, and dried for oxygen and hydrogen in the separation, cooling, and drying device 104, and then the oxygen and hydrogen are stored in the oxygen storage tank 5 and the hydrogen storage tank 6 respectively through the first oxygen pipeline 111 and the first hydrogen pipeline 112. The produced oxygen is used for boiler combustion support in the power plant and other oxygen-requiring users 10, and the produced hydrogen is used to replace the fuel oil for combustion support in the power plant and to produce ammonia in the power plant.

[0044] For the boiler ignition and combustion support part, when the thermal power plant 3 needs ignition or combustion support, hydrogen enters the gas mixer 8 from the hydrogen storage tank 6 through the second hydrogen pipeline 611. At the same time, oxygen enters the gas mixer 8 from the oxygen storage tank 5 through the second oxygen pipeline 511. Air passes through the air preheater 303 in the thermal power plant 3 and enters the gas mixer 8 through the air delivery pipeline 312. The flow rates of hydrogen, oxygen, and air are controlled and adjusted according to the boiler operation requirements and enter the boiler burner 301 through the first gas pipeline 811 to ensure the stability and efficiency of the combustion process.

[0045] For the ammonia production and denitrification part, air is compressed, condensed, and filtered in the air separation and nitrogen production device 2, and nitrogen is extracted and stored in the nitrogen storage tank 7 by using fractional distillation technology. Hydrogen in the hydrogen storage tank 6 enters the hydrogen-nitrogen mixing device 401 through the third hydrogen pipeline 612, and nitrogen in the nitrogen storage tank 7 enters the hydrogen-nitrogen mixing device 401 through the nitrogen pipeline 711. Hydrogen and nitrogen are mixed in the hydrogen-nitrogen mixing device 401 according to a set ratio and then enter the hydrogen-nitrogen reaction device 402, where an ammonia synthesis reaction occurs under high temperature and high pressure conditions. The reaction mixture gas enters the gas separator 403 through the second gas pipeline 4021 for separation of ammonia, hydrogen, and nitrogen. The separated hydrogen and nitrogen are respectively recycled to the hydrogen-nitrogen reaction device 402 through the hydrogen return pipeline 4031 and the nitrogen return pipeline 4032 for reuse, while the separated ammonia enters the ammonia storage tank 404 for storage through a pipeline. When the thermal power plant 3 needs denitrification, ammonia in the ammonia storage tank 404 enters the denitrification device 304 through the ammonia pipeline 411 and fully mixes with NOx in the flue gas at the boiler tail to undergo a reduction reaction for flue gas denitrification.

[0046] The hydrogen and ammonia production system deployed inside the thermal power plant in the present invention uses the redundant power during the deep peak shaving stage of the unit to produce hydrogen through the alkaline electrolysis water process, reducing the deep peak shaving load of the unit. The hydrogen generated in the system is used for ignition or combustion support of the boiler burner, replacing traditional boiler fuel, thereby reducing the dependence on fossil fuels and carbon emissions. At the same time, hydrogen and nitrogen are used to synthesize ammonia to replace purchased urea for boiler denitrification, reducing the operating cost and the use of chemical substances. This system ensures the stable operation of the thermal power unit within a wider load range, provides a stable regulation capacity for new energy grid connection, significantly improves the response flexibility and operating efficiency of the power generation system, and promotes the optimization of the energy structure.

[0047] The foregoing has shown and described the basic principles, main features and advantages of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention. Any reference signs in the claims should not be construed as limiting the claims involved.

[0048] In addition, it should be understood that although this specification is described in terms of embodiments, not every embodiment only contains an independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only to illustrate the technical idea of the present invention, and the protection scope of the present invention cannot be limited thereby. Any modification made on the basis of the technical solution according to the technical idea proposed by the present invention falls within the protection scope of the claims of the present invention.

Claims

1. A hydrogen and ammonia production system in a thermal power plant, characterized in that: It comprises a hydrogen production device (1), an air separation nitrogen production device (2), a thermal power plant (3), an ammonia production device (4), an oxygen storage tank (5), a hydrogen storage tank (6), a nitrogen storage tank (7), a gas mixer (8) and a step-down inverter device (9); The hydrogen production device (1) is connected to an oxygen storage tank (5) and a hydrogen storage tank (6) respectively. The oxygen storage tank (5) is connected to other oxygen demanding users (10) and a gas mixer (8) respectively. The hydrogen storage tank (6) is connected to the gas mixer (8) and an ammonia production device (4) respectively. The gas mixer (8) is connected to a thermal power plant (3). The air separation nitrogen production device (2) is connected to a nitrogen storage tank (7) and an ammonia production device (4) in sequence. The ammonia production device (4) is connected to a thermal power plant (3). The thermal power plant (3) is connected to a gas mixer (8) and a step-down inverter device (9) respectively. The step-down inverter device (9) is connected to the hydrogen production device (1) via a low voltage DC line (911).

2. A hydrogen and ammonia production system in a thermal power plant according to claim 1, characterized in that: The hydrogen production device (1) comprises a water supply tank (101), an alkaline electrolyte tank (102), an alkaline electrolytic cell (103), a separation cooling and drying device (104) and a low-voltage direct current line (911). The low-voltage direct current line (911) is connected to the alkaline electrolytic cell (103). The alkaline electrolytic cell (103) is respectively connected to the water supply tank (101), the alkaline electrolyte tank (102) and the separation cooling and drying device (104). The separation cooling and drying device (104) is respectively connected to an oxygen storage tank (5) and a hydrogen storage tank (6).

3. A hydrogen and ammonia production system in a thermal power plant according to claim 2, characterized in that: The thermal power plant (3) comprises a boiler burner (301), a power generation system (302), an air preheater (303) and a denitration device (304); the boiler burner (301), the power generation system (302), the air preheater (303) and the denitration device (304) are arranged in the thermal power plant (3); the gas mixer (8) is connected to the boiler burner (301), the air preheater (303) is connected to the gas mixer (8), the denitration device (304) is connected to the ammonia production device (4), and the power generation system (302) is connected to the step-down inverter device (9).

4. A hydrogen and ammonia production system in a thermal power plant according to claim 3, characterized in that: The ammonia production device (4) comprises a hydrogen-nitrogen mixing device (401), a hydrogen-nitrogen reaction device (402), a gas separator (403), an ammonia storage tank (404), a hydrogen reflux pipeline (4031) and a nitrogen reflux pipeline (4032); the hydrogen-nitrogen mixing device (401) is connected to the hydrogen storage tank (6), the nitrogen storage tank (7) and the hydrogen-nitrogen reaction device (402); the hydrogen-nitrogen reaction device (402) is connected to the gas separator (403), the ammonia storage tank (404) and the thermal power plant (3) in sequence; and the gas separator (403) is connected to the hydrogen-nitrogen reaction device (402) via the hydrogen reflux pipeline (4031) and the nitrogen reflux pipeline (4032).

5. The operating method of a hydrogen-ammonia production system in a thermal power plant according to claim 4, characterized in that: The invention comprises an electrolytic hydrogen and oxygen production part, a boiler ignition and combustion-supporting part and an ammonia production and denitrification part. The redundant electricity of the thermal power plant (3) during the deep peak regulation stage is used to produce hydrogen through an alkaline water electrolysis process. The produced hydrogen and oxygen are mixed with air and used for ignition or combustion-supporting of the boiler burner (301). At the same time, the nitrogen extracted from the air separation nitrogen production device (2) and the produced hydrogen are used to synthesize ammonia.

6. The operating method of a hydrogen-ammonia production system in a thermal power plant according to claim 5, characterized in that: In the electrolytic hydrogen and oxygen production part, during the deep peak regulation stage of the thermal power unit, when the power generated by the unit exceeds the demand, the redundant power generated by the thermal power plant (3) enters the step-down inverter device (9), completes the step-down and conversion into direct current, and enters the alkaline electrolytic cell (103) through the low-voltage direct current line (911) for electrolysis. The water supply tank (101) and the alkaline electrolyte tank (102) replenish water and alkaline electrolyte in time according to the electrolysis situation of the alkaline electrolytic cell (103). The products after electrolysis are separated, cooled and dried in the separation, cooling and drying device (104), and then the oxygen and hydrogen are stored in the oxygen storage tank (5) and the hydrogen storage tank (6), respectively.

7. The operating method of a hydrogen-ammonia production system in a thermal power plant according to claim 5, characterized in that: The produced oxygen is used to support combustion in power plant boilers and for other oxygen-demanding users (10).

8. The operating method of a hydrogen-ammonia production system in a thermal power plant according to claim 5, characterized in that: The produced hydrogen is used to replace the fuel oil in power plants and to produce ammonia in power plants.

9. The operating method of a hydrogen-ammonia production system in a thermal power plant according to claim 5, characterized in that: In the boiler ignition and combustion-supporting part, when the thermal power plant (3) needs ignition or combustion-supporting, hydrogen enters the gas mixer (8) from the hydrogen storage tank (6), and oxygen enters the gas mixer (8) from the oxygen storage tank (5). Air enters the gas mixer (8) through the air preheater (303) in the thermal power plant (3), and the flow rates of hydrogen, oxygen and air are controlled and adjusted according to the boiler operation requirements to enter the boiler burner (301).

10. The operating method of a hydrogen-ammonia production system in a thermal power plant according to claim 5, characterized in that: In the ammonia production and denitrification part, after air is compressed, condensed and filtered in the air separation nitrogen production device (2), nitrogen is extracted by distillation technology and stored in the nitrogen storage tank (7), the hydrogen in the hydrogen storage tank (6) enters the hydrogen-nitrogen mixing device (401), and the nitrogen in the nitrogen storage tank (7) enters the hydrogen-nitrogen mixing device (401). The hydrogen and nitrogen are mixed in the hydrogen-nitrogen mixing device (401) according to a set ratio and then enter the hydrogen-nitrogen reaction device (402), where an ammonia synthesis reaction is carried out under high temperature and high pressure conditions. The mixed gas after the reaction The gas enters the gas separator (403) to separate ammonia, hydrogen and nitrogen. The separated hydrogen and nitrogen are respectively returned to the hydrogen-nitrogen reaction device (402) through the hydrogen reflux pipeline (4031) and the nitrogen reflux pipeline (4032) for reuse, while the separated ammonia enters the ammonia storage tank (404) through the pipeline for storage. When the thermal power plant (3) needs to denitrate, the ammonia in the ammonia storage tank (404) enters the denitrification device (304) and is fully mixed with the NOx in the flue gas at the tail of the boiler to generate a reduction reaction to denitrate the flue gas.

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