Coal-fired power plant system for boiler ammonia-doped combustion by utilizing urea hydrolysis ammonia production

Abstract

The utility model relates to a coal-fired power plant system for boiler ammonia-doped combustion through urea hydrolysis ammonia production. The coal-fired power plant system comprises a urea hydrolysis ammonia production module, an ammonia gas storage and conveying module, a coal-fired power plant ammonia-doped combustion module and a waste heat recovery and utilization module. The urea hydrolysis ammonia production module produces ammonia gas, and the waste heat recovery module utilizes waste heat through heat exchange. The ammonia gas storage and conveying module separates carbon dioxide and water vapor, and stores and conveys ammonia gas to the ammonia-doped combustion module of the coal-fired power plant. According to the module, ammonia gas and pulverized coal are mixed and combusted, by accurately controlling the mixing and combustion process, generation of nitric oxide is reduced, the combustion condition is optimized, and the environment-friendly requirement is met. The whole system realizes efficient utilization of ammonia gas and environment-friendly upgrading of a coal-fired power plant.

Description

Technical Field

[0001] This utility model relates to a coal-fired power plant system that utilizes urea hydrolysis to produce ammonia for boiler combustion with ammonia blending, belonging to the field of energy conservation and emission reduction technology for coal-fired power plants. Background Technology

[0002] With the acceleration of industrialization, coal-fired power plants have become crucial in the power supply. However, traditional coal-fired power plants suffer from problems such as low combustion efficiency, severe greenhouse gas emissions, and low energy utilization efficiency. Low combustion efficiency is mainly reflected in the incomplete combustion of pulverized coal, leading to a waste of coal resources. Severe greenhouse gas emissions are due to the large amounts of carbon dioxide (CO2) and other polluting gases produced by coal combustion, which have a serious impact on the environment. Low energy utilization efficiency is caused by the ineffective utilization of a large amount of waste heat during the production process of coal-fired power plants, resulting in energy waste.

[0003] In traditional coal-fired power plant denitrification systems, urea hydrolysis to ammonia production technology has gradually replaced liquid ammonia as the main method for preparing flue gas denitrification reducing agents. This process generates ammonia (NH3) through the hydrolysis of urea and is widely favored for its safety, efficiency, and environmental friendliness. However, this technology currently has a limitation: the ammonia produced by hydrolysis is only used in the denitrification process and has not been integrated with ammonia-blended combustion technology in coal-fired boilers. This isolated application hinders the full recycling of ammonia resources, thus limiting its further application potential in reducing carbon emissions. Utility Model Content

[0004] In order to solve the problems existing in the prior art, this utility model proposes a coal-fired power plant system that uses urea hydrolysis to produce ammonia for boiler combustion with ammonia blending.

[0005] The technical solution of this utility model is as follows:

[0006] A coal-fired power plant system that utilizes urea hydrolysis to produce ammonia for boiler combustion with ammonia blending includes a urea hydrolysis ammonia production module, an ammonia storage and transportation module, a coal-fired power plant ammonia blending combustion module, and a waste heat recovery and utilization module.

[0007] The urea hydrolysis ammonia production module is connected to the waste heat recovery and utilization module, the output end of the waste heat recovery and utilization module is connected to the input end of the ammonia storage and transportation module, and the output end of the ammonia storage and transportation module is connected to the input end of the ammonia-blended combustion module of the coal-fired power plant.

[0008] The urea hydrolysis ammonia production module is used to produce ammonia gas.

[0009] The ammonia storage and transportation module is used to separate carbon dioxide and water vapor from ammonia, store ammonia, and transport ammonia to the ammonia-blended combustion module of a coal-fired power plant.

[0010] The ammonia-blended combustion module for coal-fired power plants mixes ammonia gas with pulverized coal and uses it as a raw material for combustion in coal-fired power plants.

[0011] The waste heat recovery and utilization module is used for heat exchange.

[0012] As a preferred embodiment of the present invention, the urea hydrolysis ammonia production module includes a bucket elevator, a demineralized water conveying pipeline, a urea dissolving tank, a urea dissolving pump, a urea solution storage tank, a urea solution conveying pump, and a urea hydrolysis reactor.

[0013] Urea granules are transported to the input end of the urea dissolving tank via a bucket elevator. The output end of the demineralized water delivery pipeline is connected to the input end of the urea dissolving tank. The output end of the urea dissolving tank is connected to the input end of the urea solution storage tank via a urea dissolving pump. The output end of the urea solution storage tank is connected to the input end of the urea hydrolysis reactor via a urea solution delivery pump.

[0014] The output end of the urea hydrolysis reactor is connected to the input end of the waste heat recovery and utilization module;

[0015] The urea dissolving tank is used to dissolve urea particles into a urea solution;

[0016] The urea solution storage tank is used to store urea solution.

[0017] In a preferred embodiment of this utility model, the waste heat recovery and utilization module includes a waste heat recovery device;

[0018] The waste heat recovery device is connected to the urea hydrolysis reactor;

[0019] The output end of the waste heat recovery device is connected to the ammonia storage and transportation module.

[0020] The waste heat recovery device is used for heat exchange, preheating the input urea solution to the urea hydrolysis reactor, and preheating other process water in the coal-fired power plant system.

[0021] In a preferred embodiment of the present invention, the ammonia storage and transportation module includes a cooler, a separator, and an ammonia storage tank.

[0022] The output end of the waste heat recovery device is connected to the input end of the cooler, the output end of the cooler is connected to the input end of the separator, the output end of the separator is connected to the input end of the ammonia storage tank, and is connected to the input end of the urea hydrolysis reactor through a filter. The output end of the ammonia storage tank is connected to the ammonia-blended combustion module of the coal-fired power plant through an ammonia transmission pipeline.

[0023] The ammonia storage tank is equipped with a pressure monitoring device and a safety valve;

[0024] The safety valve is used for pressure relief.

[0025] As a preferred embodiment of this utility model, the ammonia gas transmission pipeline is equipped with a pressure regulating device, a flow regulating device, an ammonia gas leakage detection device, and an emergency shut-off valve.

[0026] As a preferred embodiment of the present invention, the ammonia-blended combustion module for a coal-fired power plant includes a coal-fired boiler, pulverized coal and primary air conveying pipelines, and a control system.

[0027] The coal-fired boiler includes an ignition device, a mixed ammonia burner, and a boiler furnace.

[0028] The boiler furnace is equipped with a furnace monitoring system;

[0029] The furnace monitoring system is communicatively connected to the control system;

[0030] The output end of the ammonia gas conveying pipeline and the output end of the pulverized coal and primary air conveying pipeline are connected to the input end of the mixed ammonia burner.

[0031] The output end of the ammonia-mixed burner is connected to the input end of the boiler furnace;

[0032] The ammonia-mixed burner is used to mix pulverized coal and ammonia carried by the primary air.

[0033] The ignition device is used to ignite the mixed pulverized coal and ammonia gas.

[0034] The control system is used to control the operating parameters of the ammonia-mixed burner.

[0035] This utility model has the following beneficial effects:

[0036] This utility model's waste heat recovery device recovers the heat from the urea hydrolysis reaction, which is used to preheat the urea solution entering the urea hydrolysis reactor and to preheat other process water in coal-fired power plant systems, reducing system energy consumption and improving energy utilization efficiency. By precisely controlling the mixing and combustion process of ammonia and pulverized coal, the combustion conditions are optimized, effectively reducing the generation of nitrogen oxides during pulverized coal combustion and meeting environmental protection requirements. Detection devices on the ammonia delivery pipeline promptly detect leaks, and emergency shut-off valves quickly cut off the gas supply to prevent accidents from escalating and ensure safe system operation. Pressure monitoring devices in the ammonia storage tank monitor the pressure in real time; in case of overpressure, the safety valve automatically releases pressure to ensure storage safety. Attached Figure Description

[0037] Figure 1 This is a module connection diagram of this utility model.

[0038] Figure 2 This is a system connection diagram of this utility model.

[0039] The symbols in the attached diagram are as follows:

[0040] 1. Bucket elevator; 2. Demineralized water conveying pipeline; 3. Urea dissolving tank; 4. Urea dissolving pump; 5. Urea solution storage tank; 6. Urea solution conveying pump; 7. Urea hydrolysis reactor; 8. Waste heat recovery device; 9. Cooler; 10. Separator; 11. Ammonia storage tank; 12. Pressure monitoring device; 13. Safety valve; 14. Ammonia conveying pipeline; 15. Pressure regulating device; 16. Flow regulating device; 17. Ammonia leak detection device; 18. Emergency shut-off valve; 19. Coal-fired boiler; 20. Pulverized coal and primary air conveying pipeline; 21. Ignition device; 22. Mixed ammonia burner; 23. Boiler furnace; 24. Furnace monitoring system; 25. Control system; 26. Filter. Detailed Implementation

[0041] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0042] It should be understood that the step numbers used in the text are for ease of description only and are not intended to limit the order in which the steps are performed.

[0043] It should be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0044] The terms “comprising” and “including” indicate the presence of the described feature, whole, step, operation, element and / or component, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0045] The term “and / or” refers to any combination of one or more of the associated listed items, as well as all possible combinations, and includes these combinations.

[0046] Example 1:

[0047] See Figure 1-2 A coal-fired power plant system that utilizes urea hydrolysis to produce ammonia for boiler combustion with ammonia blending includes a urea hydrolysis ammonia production module, an ammonia storage and transportation module, a coal-fired power plant ammonia blending combustion module, and a waste heat recovery and utilization module.

[0048] The urea hydrolysis ammonia production module is connected to the waste heat recovery and utilization module, the output end of the waste heat recovery and utilization module is connected to the input end of the ammonia storage and transportation module, and the output end of the ammonia storage and transportation module is connected to the input end of the ammonia-blended combustion module of the coal-fired power plant.

[0049] The urea hydrolysis ammonia production module is used to produce ammonia gas.

[0050] The ammonia storage and transportation module is used to separate carbon dioxide and water vapor from ammonia, store ammonia, and transport ammonia to the ammonia-blended combustion module of a coal-fired power plant.

[0051] The ammonia-blended combustion module for coal-fired power plants mixes ammonia gas with pulverized coal and uses it as a raw material for combustion in coal-fired power plants.

[0052] The waste heat recovery and utilization module is used for heat exchange.

[0053] As a preferred embodiment of the present invention, the urea hydrolysis ammonia production module includes a bucket elevator 1, a demineralized water conveying pipeline 2, a urea dissolving tank 3, a urea dissolving pump 4, a urea solution storage tank 5, a urea solution conveying pump 6, and a urea hydrolysis reactor 7.

[0054] Urea granules are transported to the input end of urea dissolving tank 3 via bucket elevator 1. The output end of demineralized water conveying pipeline 2 is connected to the input end of urea dissolving tank 3. The output end of urea dissolving tank 3 is connected to the input end of urea solution storage tank 5 via urea dissolving pump 4. The output end of urea solution storage tank 5 is connected to the input end of urea hydrolysis reactor 7 via urea solution conveying pump 6.

[0055] The output end of the urea hydrolysis reactor 7 is connected to the input end of the waste heat recovery and utilization module;

[0056] The urea dissolving tank 3 is used to dissolve urea particles into urea solution;

[0057] The urea solution storage tank 5 is used to store urea solution.

[0058] In a preferred embodiment of the present invention, the waste heat recovery and utilization module includes a waste heat recovery device 8;

[0059] The waste heat recovery device 8 is connected to the urea hydrolysis reactor 7;

[0060] The output end of the waste heat recovery device 8 is connected to the ammonia storage and transportation module.

[0061] The waste heat recovery device (8) is used for heat exchange, preheating the input urea solution of the urea hydrolysis reactor (7), and preheating other process water in the coal-fired power plant system.

[0062] In this embodiment, the waste heat recovery device 8 uses a shell-and-tube heat exchanger to transfer the heat of the high-temperature mixed gas discharged from the hydrolysis reactor 7 to the urea solution entering the urea hydrolysis reactor 7 and other process water in the coal-fired power plant system.

[0063] In a preferred embodiment of the present invention, the ammonia storage and transportation module includes a cooler 9, a separator 10, and an ammonia storage tank 11.

[0064] The output end of the waste heat recovery device 8 is connected to the input end of the cooler 9, the output end of the cooler 9 is connected to the input end of the separator 10, the output end of the separator 10 is connected to the input end of the ammonia storage tank 11, and is connected to the input end of the urea hydrolysis reactor 7 through the filter 26. The output end of the ammonia storage tank 11 is connected to the ammonia-blended combustion module of the coal-fired power plant through the ammonia conveying pipeline 14.

[0065] The ammonia storage tank 11 is equipped with a pressure monitoring device 12 and a safety valve 13;

[0066] The safety valve 13 is used for pressure relief.

[0067] As a preferred embodiment of the present invention, the ammonia gas transmission pipeline 14 is provided with a pressure regulating device 15, a flow regulating device 16, an ammonia gas leakage detection device 17, and an emergency shut-off valve 18.

[0068] As a preferred embodiment of the present invention, the ammonia-blended combustion module for a coal-fired power plant includes a coal-fired boiler 19, a pulverized coal and primary air conveying pipeline 20, and a control system 25.

[0069] The coal-fired boiler 19 includes an ignition device 21, a mixed ammonia burner 22, and a boiler furnace 23.

[0070] The boiler furnace 23 is equipped with a furnace monitoring system 24;

[0071] The furnace monitoring system 24 is communicatively connected to the control system 25;

[0072] The output end of the ammonia gas conveying pipeline 14 and the output end of the pulverized coal and primary air conveying pipeline 20 are connected to the input end of the mixed ammonia burner 22.

[0073] The output end of the ammonia-mixed burner 22 is connected to the input end of the boiler furnace 23;

[0074] The ammonia-mixed burner 22 is used to mix pulverized coal and ammonia carried by the primary air.

[0075] The ignition device 21 is used to ignite the mixed coal powder and ammonia gas;

[0076] The control system 25 is used to control the operating parameters of the ammonia-mixed burner 22.

[0077] System Principle:

[0078] Urea granules are fed into a urea dissolving tank 3 via a bucket elevator 1, where they are dissolved in water from a demineralized water pipe 2 to form a urea solution with a mass fraction between 40% and 60%. The solution is then transported to a urea solution storage tank 5 for storage via a urea dissolving pump 4.

[0079] Using urea solution transfer pump 6, the urea solution in storage tank 5 is further transported to urea hydrolysis reactor 7, where a hydrolysis reaction occurs, generating a high-temperature mixed gas containing ammonia, carbon dioxide, and water vapor. This high-temperature mixed gas first flows through waste heat recovery device 8 for heat exchange, and then enters cooler 9 for further temperature reduction. Afterward, the gas enters separator 10, where moisture and carbon dioxide are removed through physical and chemical means, ultimately yielding ammonia with a purity exceeding 99%. Simultaneously, the residual liquid separated from separator 10 is filtered by filter 26 and returned to urea hydrolysis reactor 7 for recycling, minimizing raw material waste.

[0080] The purified ammonia gas is stored in ammonia storage tank 11, the pressure of which is precisely controlled between 0.2 and 0.4 MPa. To ensure storage safety, the pressure inside the storage tank is monitored in real time by a pressure monitoring device 12. Once the pressure exceeds the preset upper limit, the safety valve 13 will immediately activate to implement safety measures such as pressure relief.

[0081] According to the ammonia-blended combustion load requirements of the coal-fired power plant, ammonia gas can be delivered to the nozzle of the ammonia-blended burner 22 of the coal-fired boiler 19 at a stable and controlled flow rate and pressure through the ammonia gas transmission pipeline 14, as well as the pressure regulating device 15 and the flow regulating device 16 on the pipeline; if the ammonia gas leakage detection device 17 detects an ammonia gas leak during the transmission process, the transmission will be interrupted through the emergency shut-off valve 18 to ensure safety.

[0082] At the nozzle of the ammonia-mixed burner 22, pulverized coal from the pulverized coal and primary air conveying pipe 20 is precisely mixed with air and ammonia from the ammonia conveying pipe 14. This mixture is ignited by the ignition device 21 and fed into the boiler furnace 23 for efficient combustion in a preset ratio. It is worth mentioning that the nozzle angle of the ammonia-mixed burner 22 can be flexibly adjusted within a certain range, and its injection rate can also be finely controlled according to the actual combustion conditions.

[0083] During combustion, the furnace monitoring system 24 continuously and in real-time monitors important parameters such as furnace temperature, oxygen content, and nitrogen oxide emissions. If the furnace temperature rises abnormally, the system adjusts the strategy promptly, for example, by increasing the ammonia ratio to reduce combustion intensity. Similarly, if nitrogen oxide emissions exceed the standard, the control system 25 quickly adjusts the operating parameters of the ammonia-mixed burner 22, such as by reducing the injection rate or adjusting the nozzle angle, to optimize the ammonia injection strategy, thereby further improving the combustion process and effectively reducing nitrogen oxide emissions.

[0084] In this application embodiment, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent the existence of A alone, A and B simultaneously, or B alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, at least one of a, b, and c can represent: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, and c can be single or multiple. The above descriptions are merely embodiments of this utility model and do not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made using the content of this utility model's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A coal-fired power plant system that utilizes urea hydrolysis to produce ammonia for boiler ammonia-blended combustion, characterized in that, This includes a urea hydrolysis ammonia production module, an ammonia storage and transportation module, an ammonia-blended combustion module for coal-fired power plants, and a waste heat recovery and utilization module. The urea hydrolysis ammonia production module is connected to the waste heat recovery and utilization module, the output end of the waste heat recovery and utilization module is connected to the input end of the ammonia storage and transportation module, and the output end of the ammonia storage and transportation module is connected to the input end of the ammonia-blended combustion module of the coal-fired power plant. The urea hydrolysis ammonia production module is used to produce ammonia gas. The ammonia storage and transportation module is used to separate carbon dioxide and water vapor from ammonia, store ammonia, and transport ammonia to the ammonia-blended combustion module of a coal-fired power plant. The ammonia-blended combustion module for coal-fired power plants mixes ammonia gas with pulverized coal and uses it as a raw material for combustion in coal-fired power plants. The waste heat recovery and utilization module is used for heat exchange.

2. The coal-fired power plant system for ammonia production via urea hydrolysis for boiler combustion according to claim 1, characterized in that, The urea hydrolysis ammonia production module includes a bucket elevator (1), a demineralized water conveying pipeline (2), a urea dissolving tank (3), a urea dissolving pump (4), a urea solution storage tank (5), a urea solution conveying pump (6), and a urea hydrolysis reactor (7); Urea granules are transported to the input end of the urea dissolving tank (3) via a bucket elevator (1). The output end of the demineralized water conveying pipeline (2) is connected to the input end of the urea dissolving tank (3). The output end of the urea dissolving tank (3) is connected to the input end of the urea solution storage tank (5) via a urea dissolving pump (4). The output end of the urea solution storage tank (5) is connected to the input end of the urea hydrolysis reactor (7) via a urea solution conveying pump (6). The output end of the urea hydrolysis reactor (7) is connected to the input end of the waste heat recovery and utilization module; The urea dissolving tank (3) is used to dissolve urea particles into urea solution; The urea solution storage tank (5) is used to store urea solution.

3. The coal-fired power plant system for ammonia production via urea hydrolysis for boiler combustion according to claim 2, characterized in that, The waste heat recovery and utilization module includes a waste heat recovery device (8); The waste heat recovery device (8) is connected to the urea hydrolysis reactor (7); The output end of the waste heat recovery device (8) is connected to the ammonia storage and transportation module; The waste heat recovery device (8) is used for heat exchange, preheating the input urea solution of the urea hydrolysis reactor (7), and preheating other process water in the coal-fired power plant system.

4. The coal-fired power plant system for ammonia production via urea hydrolysis for boiler combustion according to claim 3, characterized in that, The ammonia storage and transportation module includes a cooler (9), a separator (10), and an ammonia storage tank (11); The output end of the waste heat recovery device (8) is connected to the input end of the cooler (9), the output end of the cooler (9) is connected to the input end of the separator (10), the output end of the separator (10) is connected to the input end of the ammonia storage tank (11) and the input end of the urea hydrolysis reactor (7) through the filter (26), and the output end of the ammonia storage tank (11) is connected to the ammonia-blended combustion module of the coal-fired power plant through the ammonia conveying pipeline (14); The ammonia storage tank (11) is equipped with a pressure monitoring device (12) and a safety valve (13); The safety valve (13) is used for pressure relief.

5. The coal-fired power plant system for ammonia production via urea hydrolysis for boiler combustion according to claim 4, characterized in that, The ammonia transmission pipeline (14) is equipped with a pressure regulating device (15), a flow regulating device (16), an ammonia leak detection device (17), and an emergency shut-off valve (18).

6. The coal-fired power plant system for ammonia production via urea hydrolysis for boiler combustion according to claim 5, characterized in that, The ammonia-blended combustion module for the coal-fired power plant includes a coal-fired boiler (19), pulverized coal and primary air conveying pipelines (20), and a control system (25); The coal-fired boiler (19) includes an ignition device (21), a mixed ammonia burner (22), and a boiler furnace (23); The boiler furnace (23) is equipped with a furnace monitoring system (24); The furnace monitoring system (24) is communicatively connected to the control system (25); The output end of the ammonia gas conveying pipeline (14) and the output end of the pulverized coal and primary air conveying pipeline (20) are connected to the input end of the mixed ammonia burner (22); The output end of the ammonia-mixed burner (22) is connected to the input end of the boiler furnace (23); The ammonia-mixed burner (22) is used to mix the pulverized coal and ammonia carried by the primary air. The ignition device (21) is used to ignite the mixed coal powder and ammonia gas; The control system (25) is used to control the operating parameters of the ammonia-mixed burner (22).

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