Carbon reduction and decarburization method and system for coal-fired power plant

Abstract

The invention relates to a carbon reduction and decarbonization method and system for a coal-fired power plant. The carbon reduction and decarburization method for the coal-fired power plant comprises the following steps: S1, ammonia-process carbon capture: capturing carbon dioxide in flue gas by using ammonia water through a decarburization tower to generate an ammonium bicarbonate solution; s2, carbon sequestration of the pennisetum sinese, diluting the solution, using the diluted solution as a liquid nitrogen fertilizer for growth of the pennisetum sinese, using carbon dioxide in tail gas of a decarburization tower as a gas fertilizer through an automatic industrial planting system, and using a byproduct in a carbon capture process as a nitrogen fertilizer; and S3, biomass blending combustion is conducted, the mature pennisetum sinese is naturally aired and dried through boiler waste heat to be prepared into biomass fuel, and the biomass fuel replaces part of fire coal to be put into a power plant boiler for biomass blending combustion power generation. According to the carbon reduction and decarburization method for the coal-fired power plant, provided by the invention, triple carbon reduction technologies of carbon dioxide capture, plant carbon sequestration and biomass energy blending combustion are integrated, so that a closed-loop deep decarburization system is formed; while the carbon capture efficiency is improved, clean energy replacement and resource utilization are realized.

Description

Technical Field

[0001] This invention relates to the field of integrated decarbonization technology, and more specifically, to a method and system for reducing and decarbonizing carbon in coal-fired power plants. Background Technology

[0003] Carbon capture technology is one of the key technologies for addressing global climate change and reducing greenhouse gas emissions. Carbon capture technologies are mainly divided into pre-combustion capture, post-combustion capture, and oxy-fuel combustion. Pre-combustion capture has the advantages of low energy consumption and large capture capacity. However, due to the high gas pressure processed in pre-combustion capture, its application range is relatively limited. Oxy-fuel combustion technology is expensive. Post-combustion capture technology is suitable for traditional coal-fired power plants, mainly capturing CO2 from flue gas through chemical absorption. Based on the properties of the absorbent, post-combustion capture can be divided into inorganic ammonia capture and organic amine capture. Compared with organic amine capture, inorganic ammonia capture has received widespread attention due to its lower cost, lower energy consumption, and larger product demand.

[0004] Inorganic ammonia-based carbon capture technology utilizes ammonia water as an absorbent. Ammonia water reacts with CO2 to generate ammonium bicarbonate, which is then dissolved and crystallized to fix and utilize CO2. However, traditional carbon capture methods mostly focus on the direct capture of carbon dioxide, failing to effectively integrate carbon sequestration with energy utilization. Therefore, how to combine carbon sequestration with clean energy utilization while achieving carbon dioxide capture has become a current research hotspot. Thus, there is an urgent need to develop a carbon reduction, decarbonization, and recyclable system and method based on ammonia-based carbon capture, suitable for coal-fired power plants, to achieve the carbon reduction targets of coal-fired power plants. Summary of the Invention

[0005] The technical problem to be solved by this invention is how to combine carbon sequestration with clean energy utilization while achieving carbon dioxide capture, so as to achieve carbon reduction, decarbonization and recycling suitable for coal-fired power plants.

[0006] To address the aforementioned technical problems, according to one aspect of the present invention, a method for carbon reduction and decarbonization in coal-fired power plants is provided, comprising the following steps: S1, ammonia-based carbon capture, where carbon dioxide in flue gas is captured using ammonia water in a decarbonization tower to generate an ammonium bicarbonate solution; S2, giant reed carbon fixation, where the solution is diluted and used as liquid nitrogen fertilizer for the growth of giant reeds, and carbon dioxide in the tail gas of the decarbonization tower is used as gas fertilizer through an automated industrial planting system, while the byproducts of the carbon capture process are used as nitrogen fertilizer; S3, biomass co-firing, where mature giant reeds are naturally sun-dried and dried using boiler waste heat to produce biomass fuel, which replaces part of the coal in the power plant boiler for biomass co-firing power generation. This method integrates carbon dioxide capture, plant carbon fixation, and biomass co-firing technologies, forming a closed-loop deep decarbonization system. While improving carbon capture efficiency, it achieves clean energy substitution and resource utilization, demonstrating significant carbon reduction potential and environmental and economic benefits.

[0007] According to an embodiment of the present invention, a carbon reduction and decarbonization method for a coal-fired power plant is provided, wherein step S1 is the first stage of carbon reduction. Flue gas generated from the combustion of the coal-fired power plant enters from the lower middle part of the decarbonization tower and forms convection with the ammonia solution flowing down from the top of the tower, achieving full contact and completing a chemical reaction. Carbon dioxide is absorbed and fixed by the ammonia solution, ultimately existing as an ammonium bicarbonate solution and stored in a slurry tank. The saturated ammonium bicarbonate solution stored in the slurry tank is introduced into a neutralization tank through a pipeline, and water from a storage tank is introduced into the neutralization tank to appropriately dilute the slurry. When the pH and conductivity readings at the monitoring station meet the fertilization standards, a water pump is turned on to introduce liquid nitrogen fertilizer into the greenhouse, which is then sprayed onto the giant reed using an automatic sprinkler system. The gas fertilizer control valve is opened to blow the exhaust gas (carbon dioxide) discharged from the decarbonization tower into the greenhouse via a bidirectional fan as gas fertilizer for plant growth. Through the above process, carbon dioxide is recovered and reused through flue gas waste utilization.

[0008] According to an embodiment of the present invention, a carbon reduction and decarbonization method for coal-fired power plants is provided, wherein step S2 is a second stage of carbon reduction. Giant Napier grass is a highly efficient biological carbon-fixing plant with rapid growth and high carbon fixation capacity; the carbon absorption capacity of giant Napier grass can reach 20 to 30 tons per hectare per year; giant Napier grass is planted in greenhouses to improve planting efficiency; to optimize the growth environment of giant Napier grass, the system can control the spraying volume and frequency of ammonium bicarbonate solution to ensure that nitrogen fertilizer is effectively supplied to giant Napier grass at a suitable concentration; an automatic sprinkler system is used in the greenhouse where giant Napier grass is planted; the automatic sprinkler system provides... Nitrogen fertilizer is precisely applied to giant Napier grass to ensure it receives sufficient nutrients. A two-way fan and air vents are installed at the top of the greenhouse. When gas fertilizer needs to be applied, the gas fertilizer control valve is opened, and the two-way fan draws the gas fertilizer into the greenhouse through the air vents. When the ammonia concentration inside the greenhouse is too high, the ammonia discharge valve is opened and the gas fertilizer control valve is closed. The two-way fan then sends the ammonia from the greenhouse into the power plant boiler to mix with air for combustion, which also has a denitrification effect. After the giant Napier grass matures, the system uses an equipped automatic harvester to efficiently and quickly harvest the mature grass, reducing manual labor and improving harvesting efficiency.

[0009] According to an embodiment of the present invention, a carbon reduction and decarbonization method for coal-fired power plants is provided, wherein step S3 is the third stage of carbon reduction. The harvested giant reed grass has a high moisture content and therefore requires drying. Fresh giant reed grass has a moisture content between 70% and 85%, and excessive moisture will affect its storage and combustion. To save energy and reduce environmental pollution, the giant reed grass can be dried using a two-step drying method: natural sun exposure and boiler waste heat drying. First, the giant reed grass is placed on a drying bed and exposed to the sun to reduce its moisture content. When the moisture content is reduced to about 45%, the giant reed grass is placed in a drying bin. Boiler flue gas enters the air duct through a blower, and after the flue gas enters the drying bin to complete the drying of the giant reed grass, it returns to the boiler flue gas duct. In the drying chamber, boiler waste heat is used to dry the giant reed grass to a moisture content of 12%-15%. Giant reed grass performs excellently in the field of biomass power generation. The dried giant reed grass is used as biomass fuel in power plant boilers and co-fired with coal to generate electricity.

[0010] According to an embodiment of the present invention, a carbon reduction and decarbonization method for a coal-fired power plant is provided, wherein after performing step S3, the process can be repeated to step S1, and the flue gas generated by combustion is returned to the decarbonization tower system through a dedicated pipeline to achieve closed-loop treatment of CO2, and the flue gas generated by combustion is returned to the decarbonization tower to achieve carbon recycling.

[0011] According to another aspect of the present invention, a carbon reduction and decarbonization system for coal-fired power plants is provided, comprising: an ammonia-based carbon capture module for capturing carbon dioxide from flue gas using ammonia water through a decarbonization tower to generate ammonium bicarbonate solution; a giant reed carbon fixation module for diluting the solution and using it as liquid nitrogen fertilizer for the growth of giant reeds, utilizing carbon dioxide from the tail gas of the decarbonization tower as gas fertilizer through an automated industrial planting system, and using the by-product of the carbon capture process as nitrogen fertilizer; and a biomass co-firing module for processing mature giant reeds into biomass fuel after natural drying and drying with boiler waste heat, replacing part of the coal in the power plant boiler for biomass co-firing power generation; wherein, the ammonia-based carbon capture module for carbon dioxide capture, the giant reed carbon fixation module for plant carbon fixation, and the biomass co-firing module for biomass co-firing are integrated for a triple carbon reduction and decarbonization system, forming a closed-loop deep decarbonization system; while improving carbon capture efficiency, it realizes clean energy substitution and resource utilization, and has significant carbon reduction potential and environmental and economic benefits.

[0012] According to an embodiment of the present invention, a carbon reduction and decarbonization system for a coal-fired power plant includes an ammonia-based carbon capture module for the first stage of carbon reduction. The ammonia-based carbon capture module may include: a decarbonization tower connected to the flue gas outlet of the power plant boiler via a flue gas pipeline; a slurry tank for storing ammonium bicarbonate solution connected to the decarbonization tower; a neutralization water tank connected to a slurry-specific pipeline; a water storage tank connected to a monitoring station and a water pump; an automatic sprinkler head installed on a shed; and a gas-fertilizer control valve installed on the top of the decarbonization tower connected to the shed via a gas-fertilizer pipeline. The flue gas generated by the coal-fired power plant combustion enters from the lower middle part of the decarbonization tower and forms convection within the tower with the ammonia solution flowing down from the top, thereby achieving… The process involves thorough contact and completion of a chemical reaction. Carbon dioxide is absorbed and fixed by an ammonia solution, ultimately existing as an ammonium bicarbonate solution stored in a slurry tank. The saturated ammonium bicarbonate solution stored in the slurry tank is piped into a neutralization tank, and water from a storage tank is introduced into the neutralization tank to appropriately dilute the slurry. When the pH and conductivity readings at the monitoring station meet the fertilization standards, a water pump is turned on to introduce liquid nitrogen fertilizer into the greenhouse, which is then sprayed onto the giant reed using an automatic sprinkler system. The gas fertilizer control valve is opened, and the exhaust gas (carbon dioxide) from the decarbonization tower is blown into the greenhouse by a two-way fan as gas fertilizer for plant growth. Through this process, carbon dioxide is recovered and reused through flue gas waste utilization.

[0013] According to an embodiment of the present invention, a carbon reduction and decarbonization system for a coal-fired power plant includes a giant reed carbon fixation module for secondary carbon reduction. The giant reed carbon fixation module may include: a greenhouse, automatic sprinkler heads, a bidirectional fan, a CO2 concentration sensor, a controller, and an ammonia discharge valve. An air inlet is installed on the greenhouse, and the greenhouse and the power plant boiler are connected via an ammonia pipeline. An ammonia discharge valve is installed on the ammonia pipeline to open when the ammonia concentration in the greenhouse is too high, introducing ammonia into the power plant boiler for combustion with air. Giant reed is a highly efficient biological carbon-fixing plant with rapid growth and high carbon fixation capacity; its annual carbon absorption can reach 20 to 30 tons per hectare. Planting giant reed in a greenhouse improves the efficiency of its cultivation. To optimize the growth environment of the giant reed... The system regulates the spraying volume and frequency of ammonium bicarbonate solution to ensure effective nitrogen fertilizer supply to giant Napier grass at an appropriate concentration. An automatic sprinkler system is used inside the greenhouse where the giant Napier grass is grown. This system precisely applies nitrogen fertilizer to the grass, ensuring sufficient nutrient supply. A two-way fan and air vents are installed at the top of the greenhouse. When gas fertilizer needs to be applied, the gas fertilizer control valve is opened, and the two-way fan draws the gas fertilizer into the greenhouse through the air vents. When the ammonia concentration inside the greenhouse is too high, the ammonia discharge valve is opened, and the gas fertilizer control valve is closed. The two-way fan then sends the ammonia from the greenhouse into the power plant boiler to mix with air for combustion, which also has a denitrification effect. After the giant Napier grass matures, the system uses an equipped automatic harvester to efficiently and quickly harvest the mature grass, reducing manual labor and improving harvesting efficiency.

[0014] According to an embodiment of the present invention, a carbon reduction and decarbonization system for a coal-fired power plant includes a biomass co-firing module for third-stage carbon reduction. The biomass co-firing module may include: an automatic harvester, a drying chamber, an air duct, a fan, and a drying bin. The harvested giant reed grass has a high moisture content, thus requiring drying. Fresh giant reed grass has a moisture content between 70% and 85%, and excessive moisture will affect its storage and combustion. To save energy and reduce environmental pollution, the drying of the giant reed grass employs a two-step drying method: natural sun-drying and boiler waste heat drying. The process involves: first, placing giant reed grass on a drying bed to reduce its moisture content through sun exposure; when the moisture content drops to around 45%, placing the giant reed grass in a drying chamber; boiler flue gas entering the duct via a blower, then entering the drying chamber to dry the giant reed grass before returning to the boiler flue gas duct; and finally, using waste heat from the boiler in the drying chamber to dry the giant reed grass to a moisture content of 12%-15%. Giant reed grass performs exceptionally well in the field of biomass power generation, and the dried giant reed grass is used as biomass fuel in power plant boilers, co-fired with coal for power generation.

[0015] According to an embodiment of the present invention, a carbon reduction and decarbonization system for a coal-fired power plant is provided, wherein the flue gas generated by the combustion of the biomass co-firing module can be returned to the decarbonization tower system of the ammonia carbon capture module through a dedicated pipeline to achieve closed-loop treatment of CO2, and the flue gas generated by combustion is returned to the decarbonization tower to achieve carbon recycling.

[0016] Compared with the prior art, the technical solution provided by the embodiments of the present invention can achieve at least the following beneficial effects:

[0017] The carbon reduction and decarbonization method and system for coal-fired power plants according to the present invention can promote biological carbon sequestration. Giant Napier grass, as a highly efficient carbon sequestration plant, can absorb and fix large amounts of carbon dioxide during its growth. Its rapid growth characteristics make it an ideal carbon sequestration plant.

[0018] The carbon reduction and decarbonization method and system for coal-fired power plants according to the present invention provide a clean energy alternative by using biomass combustion to replace coal-fired power generation, which can effectively reduce carbon dioxide emissions from coal combustion and convert them into renewable clean energy, thus promoting low-carbon development.

[0019] The carbon reduction and decarbonization method and system for coal-fired power plants according to the present invention are environmentally friendly and sustainable. The present invention combines the multiple advantages of carbon dioxide capture, biological carbon sequestration and clean energy utilization, and has good environmental benefits and sustainable development potential.

[0020] The carbon reduction and decarbonization method and system for coal-fired power plants according to the present invention can reduce the operating costs of power plants. Using giant reed grass as biomass fuel to replace traditional coal can directly reduce the fuel procurement costs of power plants. Ammonium bicarbonate, a byproduct of ammonia carbon capture technology, is a high-quality nitrogen fertilizer that can be directly supplied to fertilizer plants for further processing, generating considerable economic benefits. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention.

[0022] Figure 1 This is a schematic diagram illustrating a carbon reduction and decarbonization method and system for a coal-fired power plant according to an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram showing the top of a greenhouse according to an embodiment of the present invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains. The terms “first,” “second,” and similar terms used in the specification and claims of this patent application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an” or “a” and similar terms do not indicate a limitation of quantity, but rather indicate the presence of at least one.

[0026] Figure 1 This is a schematic diagram illustrating a carbon reduction and decarbonization method and system for a coal-fired power plant according to an embodiment of the present invention.

[0027] like Figure 1 As shown, the carbon reduction and decarbonization method for coal-fired power plants includes the following steps:

[0028] S1, ammonia carbon capture: carbon dioxide in flue gas is captured by ammonia water in decarbonation tower 1 to generate ammonium bicarbonate solution.

[0029] S2, Giant Napier grass carbon fixation, the solution is diluted and used as liquid nitrogen fertilizer for the growth of Giant Napier grass 10. Through an automated industrial planting system, carbon dioxide in the tail gas of decarbonization tower 1 is used as gas fertilizer, and the by-product of the carbon capture process is used as nitrogen fertilizer.

[0030] S3. Biomass co-firing: After the mature giant reed grass 10 is naturally dried and dried with the waste heat of the boiler, it is made into biomass fuel, which replaces part of the coal and is put into the power plant boiler 16 for biomass co-firing power generation.

[0031] It integrates carbon dioxide capture, plant carbon sequestration and biomass co-firing technologies to form a closed-loop deep decarbonization system; while improving carbon capture efficiency, it realizes clean energy substitution and resource utilization, and has significant carbon reduction potential and environmental and economic benefits.

[0032] The carbon reduction and decarbonization method and system for coal-fired power plants according to the present invention provide a clean energy alternative by using biomass combustion to replace coal-fired power generation, which can effectively reduce carbon dioxide emissions from coal combustion and convert them into renewable clean energy, thus promoting low-carbon development.

[0033] According to one or more embodiments of the present invention, a method for carbon reduction and decarbonization in a coal-fired power plant is provided, wherein step S1 is the first stage of carbon reduction, in which the flue gas generated by combustion in the coal-fired power plant enters from the lower middle part of the decarbonization tower 1 and forms convection with the ammonia solution flowing down from the top of the tower, achieving full contact and completing the chemical reaction; wherein, carbon dioxide is absorbed and fixed by the ammonia solution, and finally exists in the form of ammonium bicarbonate solution and is stored in the slurry tank 2; the saturated ammonium bicarbonate solution stored in the slurry tank 2 is introduced into the middle stage through a pipeline. Water from storage tank 4 is introduced into neutralization tank 5 to dilute the slurry appropriately. When the pH and conductivity readings at monitoring station 7 meet the fertilization standards, water pump 6 is turned on to introduce liquid nitrogen fertilizer into greenhouse 8, which is then sprayed onto giant reed grass 10 using an automatic sprinkler system. Gas fertilizer control valve 18 is opened to blow the exhaust gas (carbon dioxide) discharged from decarbonization tower 1 into greenhouse 8 through bidirectional fan 19 for use as gas fertilizer for plant growth. Through the above process, carbon dioxide is recovered and reused through flue gas waste utilization.

[0034] According to one or more embodiments of the present invention, a method for carbon reduction and decarbonization in coal-fired power plants is provided, wherein step S2 is a second stage of carbon reduction, and giant reed 10 is a highly efficient biological carbon-fixing plant with rapid growth and high carbon fixation capacity; the carbon absorption capacity of giant reed 10 can reach 20 to 30 tons per hectare per year; giant reed 10 is planted in greenhouse 8 to improve the planting efficiency of giant reed 10; in order to optimize the growth environment of giant reed 10, the system regulates the spraying amount and frequency of ammonium bicarbonate solution to ensure that nitrogen fertilizer is effectively supplied to giant reed 10 at a suitable concentration; an automatic sprinkler system is used in greenhouse 8 where giant reed 10 is planted; the automatic sprinkler system provides precise water to giant reed 10. Nitrogen fertilizer is applied to ensure that the giant Napier grass 10 receives sufficient nutrients. A two-way fan 19 and an air inlet 20 are installed on the top of the greenhouse 8. When it is necessary to apply gas fertilizer to the giant Napier grass 10, the gas fertilizer control valve 18 is opened, and the two-way fan 19 is used to allow the gas fertilizer to flow from the air inlet 20 into the greenhouse 8. When the ammonia concentration in the greenhouse 8 is too high, the ammonia discharge valve 23 is opened and the gas fertilizer control valve 18 is closed. The two-way fan 19 is used to send the ammonia in the greenhouse 8 into the power plant boiler 16 to mix with air for combustion, which also has a denitrification effect. After the giant Napier grass 10 matures, the system uses the equipped automatic harvester 11 to harvest the mature giant Napier grass 10 efficiently and quickly, reducing manual labor and improving harvesting efficiency.

[0035] According to one or more embodiments of the present invention, a method for reducing carbon emissions in coal-fired power plants is provided, wherein step S3 is the third stage of carbon reduction. The harvested giant reed grass 10 has a high moisture content and therefore requires drying. Fresh giant reed grass 10 has a moisture content between 70% and 85%, and excessive moisture will affect its storage and combustion. To save energy and reduce environmental pollution, the drying of giant reed grass 10 employs a two-step drying method: natural sun exposure and boiler waste heat drying. First, the giant reed grass 10 is placed on a drying bed and exposed to sunlight to reduce its moisture content. Water content; when the moisture content drops to about 45%, the giant reed grass 10 is placed in the drying bin 15; the flue gas from the boiler enters the air duct 13 through the blower 14, and after the flue gas enters the drying bin 15 to dry the giant reed grass 10, it returns to the boiler flue gas duct 17; the giant reed grass 10 is dried to a moisture content of 12%-15% in the drying chamber 12 using the waste heat of the boiler; the giant reed grass 10 performs well in the field of biomass power generation, and the dried giant reed grass 10 is used as biomass fuel in the power plant boiler 16 and co-fired with coal to generate electricity.

[0036] According to one or more embodiments of the present invention, a carbon reduction and decarbonization method for a coal-fired power plant is provided, wherein after performing step S3, the process is repeated to step S1, and the flue gas generated by combustion is returned to the decarbonization tower 1 system through a dedicated pipeline to achieve closed-loop treatment of CO2, and the flue gas generated by combustion is returned to the decarbonization tower 1 to achieve carbon recycling.

[0037] Figure 2 This is a schematic diagram showing the top of the greenhouse 8 according to an embodiment of the present invention.

[0038] like Figure 1 and Figure 2 As shown, the carbon reduction and decarbonization system for coal-fired power plants includes: an ammonia carbon capture module, a giant reed carbon fixation module, and a biomass co-firing module.

[0039] The ammonia-based carbon capture module is used to capture carbon dioxide from flue gas using ammonia water through decarbonation tower 1, generating ammonium bicarbonate solution.

[0040] The giant reed carbon fixation module is used to dilute the solution and use it as liquid nitrogen fertilizer for the growth of giant reed 10. Through an automated industrial planting system, carbon dioxide in the tail gas of decarbonization tower 1 is used as gas fertilizer, while the by-product of the carbon capture process is used as nitrogen fertilizer.

[0041] The biomass co-firing module is used to produce biomass fuel from mature giant reed grass 10 after natural sun drying and boiler waste heat drying, which replaces part of the coal in the power plant boiler 16 for biomass co-firing power generation.

[0042] Among them, the ammonia carbon capture module for carbon dioxide capture, the giant Napier grass carbon fixation module for plant carbon fixation, and the biomass co-firing module for biomass energy co-firing are integrated into a triple carbon reduction system to form a closed-loop deep decarbonization system. While improving carbon capture efficiency, it realizes clean energy substitution and resource utilization, and has significant carbon reduction potential and environmental and economic benefits.

[0043] The carbon reduction and decarbonization method and system for coal-fired power plants according to the present invention can promote biological carbon sequestration. Giant Napier grass 10, as a highly efficient carbon sequestration plant, can absorb and fix large amounts of carbon dioxide during its growth. Its rapid growth characteristics make it an ideal carbon sequestration plant.

[0044] According to one or more embodiments of the present invention, a carbon reduction and decarbonization system for a coal-fired power plant is provided, wherein an ammonia-based carbon capture module is used for the first stage of carbon reduction. The ammonia-based carbon capture module includes: a decarbonization tower 1, which is connected to the flue gas outlet of a power plant boiler 16 via a flue gas pipe 17; the decarbonization tower 1 is connected to a slurry tank 2 for storing ammonium bicarbonate solution; the slurry tank 2 is connected to a neutralization water tank 5 via a dedicated slurry pipe 3; the neutralization water tank 5 is connected to a water storage tank 4, a monitoring station 7, and a water pump 6; the water pump 6 is connected to an automatic sprinkler head 9 installed on a greenhouse 8; the top of the decarbonization tower 1 is connected to the greenhouse 8 via a gas-fertilizer pipe; and a gas-fertilizer control valve 18 is installed on the gas-fertilizer pipe.

[0045] In this process, the flue gas generated by the combustion of coal-fired power plants enters from the lower middle part of the decarbonization tower 1 and forms convection with the ammonia solution flowing down from the top of the tower, achieving full contact and completing the chemical reaction. Carbon dioxide is absorbed and fixed by the ammonia solution, ultimately existing as ammonium bicarbonate solution and stored in the slurry tank 2. The saturated ammonium bicarbonate solution stored in the slurry tank 2 is introduced into the neutralization water tank 5 through a pipeline, and water from the storage tank 4 is introduced into the neutralization water tank 5 to appropriately dilute the slurry. When the pH and conductivity readings at the monitoring station 7 meet the fertilization standards, the water pump 6 is turned on to introduce liquid nitrogen fertilizer into the greenhouse 8, which is then sprayed onto the giant reed grass 10 using the automatic sprinkler system 9. The gas fertilizer control valve 18 is opened to blow the exhaust gas (carbon dioxide) discharged from the decarbonization tower 1 into the greenhouse 8 through the bidirectional fan 19 as gas fertilizer for plant growth. Through the above process, carbon dioxide is recovered and reused through flue gas waste utilization.

[0046] According to one or more embodiments of the present invention, a carbon reduction and decarbonization system for a coal-fired power plant is provided, wherein a giant reed carbon fixation module is used for a second stage of carbon reduction. The giant reed carbon fixation module includes: a greenhouse 8, an automatic sprinkler head 9, a bidirectional fan 19, a CO2 concentration sensor 21, a controller 22, and an ammonia discharge valve 23. An air inlet 20 is provided on the greenhouse 8. The greenhouse 8 and the power plant boiler 16 are connected through an ammonia pipeline. The ammonia pipeline is provided with an ammonia discharge valve 23, which is used to open the ammonia discharge valve 23 when the ammonia concentration in the greenhouse 8 is too high, so that the ammonia is introduced into the power plant boiler 16 and mixed with air for combustion.

[0047] Giant Napier grass 10 is a highly efficient biological carbon-fixing plant with rapid growth and high carbon fixation capacity. It can absorb 20 to 30 tons of carbon per hectare per year. Planting giant Napier grass 10 in greenhouse 8 improves planting efficiency. To optimize the growth environment, the spraying volume and frequency of ammonium bicarbonate solution are systematically controlled to ensure effective nitrogen fertilizer supply at an appropriate concentration. An automatic sprinkler system is used in greenhouse 8 to precisely apply nitrogen fertilizer to the plant, ensuring it receives sufficient nutrients. The system provides a variety of fertilizers; a two-way fan 19 and an air inlet 20 are installed on the top of greenhouse 8; when it is necessary to apply gas fertilizer to giant Napier grass 10, the gas fertilizer control valve 18 is opened, and the two-way fan 19 is used to allow the gas fertilizer to flow from the air inlet 20 into greenhouse 8; when the ammonia concentration in greenhouse 8 is too high, the ammonia discharge valve 23 is opened and the gas fertilizer control valve 18 is closed, and the two-way fan 19 is used to send the ammonia in greenhouse 8 into the power plant boiler 16 to mix with air for combustion, which also has a denitrification effect; after the giant Napier grass 10 matures, the system uses the equipped automatic harvester 11 to harvest the mature giant Napier grass 10 efficiently and quickly, reducing manual labor and improving harvesting efficiency.

[0048] According to one or more embodiments of the present invention, a carbon reduction and decarbonization system for a coal-fired power plant is provided, wherein a biomass co-firing module is used for third-stage carbon reduction, and the biomass co-firing module includes: an automatic harvester 11, a drying chamber 12, an air duct 13, a fan 14, and a hay drying bin 15.

[0049] The harvested giant reed grass 10 has a high moisture content, so it needs to be dried. The moisture content of fresh giant reed grass 10 is between 70% and 85%, and excessive moisture will affect its storage and combustion. In order to save energy and reduce environmental pollution, the drying of giant reed grass 10 adopts a two-step drying method of natural sun exposure and boiler waste heat drying. First, the giant reed grass 10 is placed on the drying bed and exposed to the sun to reduce its moisture content. When the moisture content is reduced to about 45%, the giant reed grass 10 is placed in the drying bin 15. The flue gas from the boiler enters the air duct 13 through the blower 14, and after the flue gas enters the drying bin 15 to complete the drying of the giant reed grass 10, it returns to the boiler flue gas duct 17. In the drying chamber 12, the boiler waste heat is used to dry the giant reed grass 10 to a moisture content of 12%-15%. Giant reed grass 10 performs well in the field of biomass power generation. The dried giant reed grass 10 is used as biomass fuel in the power plant boiler 16 and co-fired with coal to generate electricity.

[0050] According to one or more embodiments of the present invention, a carbon reduction and decarbonization system for a coal-fired power plant is provided, wherein the flue gas generated by the combustion of the biomass co-firing module is returned to the decarbonization tower 1 system of the ammonia carbon capture module through a dedicated pipeline to achieve closed-loop treatment of CO2, and the flue gas generated by combustion is returned to the decarbonization tower 1 to achieve carbon recycling.

[0051] The carbon reduction and decarbonization method and system for coal-fired power plants according to the present invention are environmentally friendly and sustainable. The present invention combines the multiple advantages of carbon dioxide capture, biological carbon sequestration and clean energy utilization, and has good environmental benefits and sustainable development potential.

[0052] When in use, a triple carbon reduction system based on "ammonia carbon capture - giant reed grass carbon fixation - biomass co-firing" will be constructed within the power plant. The specific process of this system is as follows:

[0053] Flue gas from the power plant boiler is introduced into decarbonization tower 1. Inside the tower, the flue gas undergoes sufficient convective contact and chemical reaction with ammonia water sprayed from the top of the tower. Approximately 80% of the CO2 is absorbed, generating ammonium bicarbonate slurry, which is stored in slurry tank 2. The saturated ammonium bicarbonate slurry is transported to neutralization water tank 5 through pipeline 3. Water from storage tank 4 is injected into neutralization water tank 5 to dilute the slurry. Monitoring station 7 monitors the pH and conductivity of the diluted solution in real time. When the pH stabilizes and the conductivity meets the fertilization standard, water pump 6 starts, transporting the diluted liquid nitrogen fertilizer through pipeline to the giant reed planting greenhouse 8.

[0054] Inside the intelligent greenhouse, the automatic sprinkler system 9 precisely and evenly sprays liquid nitrogen fertilizer onto the giant Napier grass 10 according to its growth stage, providing the nitrogen source needed for growth. Simultaneously, CO2 from the exhaust gas treated by the decarbonization tower is supplied into the greenhouse via a gas fertilizer supply pipeline, controlled by the controller 22, through a bidirectional fan 19 and an air outlet 20. A CO2 concentration sensor 21 installed inside the greenhouse monitors the concentration in real time. When the concentration falls below a set threshold, the gas fertilizer control valve 18 opens to replenish CO2; when the concentration reaches the ideal range, it closes. This "liquid fertilizer + gas fertilizer" model jointly promotes the efficient photosynthesis of the giant Napier grass, converting the atmospheric CO2 fixed during its rapid growth into biomass.

[0055] After the mature giant reed grass is harvested by the automatic harvester 11, it is first naturally sun-dried to reduce its moisture content to about 45%. Then, the giant reed grass is transferred to the drying bin 15, where it is dried again by the flue gas drawn from the tail of the boiler through the fan 14 into the air duct 13, and finally the moisture content is stabilized at 12%-15%.

[0056] The dried giant reed grass is processed into biomass fuel and delivered to the power plant boiler 16 for co-firing with coal to generate electricity. The flue gas produced by combustion is guided back to the decarbonization tower 1 system through flue gas pipe 17, where CO2 is captured again, thus forming a complete "deep carbon treatment" closed loop.

[0057] Based on the carbon reduction and decarbonization method and system for coal-fired power plants of the present invention, triple carbon reduction is achieved. The carbon reduction effect of the system is illustrated below through calculations:

[0058] A power plant emits 100 × 10⁻⁶ tons of flue gas per hour. 4 m 3 Of this, 0.05% of the flue gas enters the decarbonization tower for decarbonization. The amount of carbon dioxide fixed in the decarbonization tower can be calculated using formula (1):

[0059] (1)

[0060] In the formula, S represents the total decarbonization volume in m³. 3 A represents the total flue gas volume in m. 3 / h, 100×10 4 m 3 / h; a represents the percentage of total flue gas entering the decarbonization tower, 0.05%; C represents the percentage of carbon dioxide in the flue gas, taken as 15%; The decarbonization efficiency is expressed as 80%; T represents the decarbonization time in hours, expressed as 3000 hours. The total fixed volume of carbon dioxide calculated using the formula is 1.8 × 10⁻⁶. 5 m 3 The density of carbon dioxide is known to be 1.98 kg / m³. 3Substituting into formula (2), the calculated carbon dioxide fixation mass is 356.4 tons.

[0061] (2)

[0062] Giant Napier grass typically absorbs 20 to 30 tons of CO2 per hectare per year. The power plant planted 80 mu (approximately 5.3 hectares) of giant Napier grass. The carbon sequestration of the giant Napier grass was calculated using formula (3), where s is the carbon absorption of the giant Napier grass and h is the planting area of ​​the giant Napier grass. The calculated value was 132.25 tons.

[0063] (3)

[0064] The electricity generated by burning giant reed grass per mu is equivalent to the electricity generated by burning 4-5 tons of raw coal. 80 mu of giant reed grass can replace 360 ​​tons of coal for power generation. The carbon dioxide emissions of 70 tons of coal are approximately between 161 and 196 tons. In formula (4), h represents the planting area of ​​giant reed grass. K represents the amount of coal that can be replaced by burning giant reed grass per mu. K is taken as 4.5 tons. Using formula (4), it can be obtained that 80 mu of giant reed grass as biomass to replace coal for power generation can reduce carbon emissions by approximately 977 tons.

[0065] (4)

[0066] The power plant's comprehensive decarbonization system, which utilizes ammonia carbon capture, giant reed grass for carbon sequestration, and biomass combustion to achieve triple carbon reduction, has a total annual carbon reduction of 1465.65 tons.

[0067] The carbon reduction and decarbonization method and system for coal-fired power plants according to the present invention can reduce the operating costs of power plants. Using giant reed grass as biomass fuel to replace traditional coal can directly reduce the fuel procurement costs of power plants. Ammonium bicarbonate, a byproduct of ammonia carbon capture technology, is a high-quality nitrogen fertilizer that can be directly supplied to fertilizer plants for further processing, generating considerable economic benefits.

[0068] The above description is merely an exemplary embodiment of the present invention and is not intended to limit the scope of protection of the present invention, which is determined by the appended claims.

Claims

1. A method for reducing and decarbonizing carbon in coal-fired power plants, comprising the following steps: S1. Ammonia carbon capture: Carbon dioxide in flue gas is captured by ammonia water in a decarbonation tower to generate ammonium bicarbonate solution. S2. Giant Napier grass carbon fixation: The solution is diluted and used as liquid nitrogen fertilizer for the growth of giant Napier grass. Through an automated industrial planting system, carbon dioxide in the tail gas of the decarbonization tower is used as gas fertilizer, while the by-product of the carbon capture process is used as nitrogen fertilizer. S3. Biomass co-firing: Mature giant reeds are naturally sun-dried and then dried using waste heat from boilers to produce biomass fuel, which replaces a portion of coal in power plant boilers for biomass co-firing power generation. in, It integrates carbon dioxide capture, plant carbon sequestration, and biomass co-firing technologies to form a closed-loop deep decarbonization system. While improving carbon capture efficiency, it also achieves clean energy substitution and resource utilization, demonstrating significant carbon reduction potential and environmental and economic benefits.

2. The carbon reduction and decarbonization method for coal-fired power plants as described in claim 1, wherein, Step S1 is the first stage of carbon reduction. The flue gas generated by the coal-fired power plant enters from the lower middle part of the decarbonization tower and forms convection with the ammonia solution flowing down from the top of the tower, achieving full contact and completing the chemical reaction. Among them, carbon dioxide is absorbed and fixed by the ammonia solution, and finally exists in the form of ammonium bicarbonate solution and is stored in the slurry tank. The saturated ammonium bicarbonate solution stored in the slurry tank is introduced into the neutralization water tank through pipeline, and water from the water storage tank is introduced into the neutralization water tank to appropriately dilute the slurry. When the pH and conductivity readings at the monitoring station meet the fertilization standards, the water pump is turned on to introduce liquid nitrogen fertilizer into the greenhouse, and the automatic sprinkler system is used to spray it on the giant reed grass. The gas fertilizer control valve is opened to blow the tail gas discharged from the decarbonization tower, i.e., carbon dioxide, into the greenhouse through a two-way fan as gas fertilizer needed for plant growth. Through the above process, carbon dioxide is recovered and reused through flue gas waste utilization.

3. The carbon reduction and decarbonization method for coal-fired power plants as described in claim 1, wherein, Step S2 is the second stage of carbon reduction. Giant Napier grass is a highly efficient biological carbon-fixing plant with rapid growth and high carbon fixation capacity; its annual carbon absorption can reach 20 to 30 tons per hectare. Planting giant Napier grass in greenhouses improves planting efficiency. To optimize the growth environment, the system regulates the spraying volume and frequency of ammonium bicarbonate solution to ensure effective nitrogen fertilizer supply at an appropriate concentration. An automatic sprinkler system is used in the greenhouses where giant Napier grass is planted. This automatic sprinkler system precisely applies nitrogen fertilizer to the giant Napier grass, ensuring optimal carbon reduction. The grass receives ample nutrient supply; bidirectional fans and air vents are installed at the top of the greenhouse; when it is necessary to apply gas fertilizer to the giant Napier grass, the gas fertilizer control valve is opened, and the bidirectional fans allow the gas fertilizer to flow into the greenhouse from the air vents; when the ammonia concentration in the greenhouse is too high, the ammonia discharge valve is opened and the gas fertilizer control valve is closed, and the bidirectional fans send the ammonia in the greenhouse into the power plant boiler to mix with air for combustion, which also has a denitrification effect; after the giant Napier grass matures, the system uses the equipped automatic harvester to efficiently and quickly harvest the mature giant Napier grass, reducing manual labor and improving harvesting efficiency.

4. The carbon reduction and decarbonization method for coal-fired power plants as described in claim 1, wherein, Step S3 is the third stage of carbon reduction. The harvested giant reed grass has a high moisture content, thus requiring drying. Fresh giant reed grass has a moisture content between 70% and 85%, and excessive moisture will affect its storage and combustion. The drying process employs a two-step method: natural sun exposure and boiler waste heat drying. First, the giant reed grass is placed on a drying bed and exposed to the sun to reduce its moisture content. When the moisture content drops to approximately 45%, the giant reed grass is placed in a drying chamber. Boiler flue gas enters the duct through a blower, then enters the drying chamber to complete the drying of the giant reed grass before returning to the boiler flue gas duct. In the drying chamber, boiler waste heat is used to dry the giant reed grass to a moisture content of 12%-15%. Giant reed grass performs excellently in biomass power generation; the dried giant reed grass is used as biomass fuel in power plant boilers, co-fired with coal for power generation.

5. The carbon reduction and decarbonization method for coal-fired power plants as described in claim 1, wherein, After executing step S3, the process returns to step S1. The flue gas generated by combustion is returned to the decarbonization tower system through a dedicated pipeline to achieve closed-loop treatment of CO2 and carbon recycling.

6. A carbon reduction and decarbonization system for coal-fired power plants, wherein, include: The ammonia-based carbon capture module is used to capture carbon dioxide from flue gas using ammonia water through a decarbonation tower, generating ammonium bicarbonate solution. The giant reed carbon fixation module is used to dilute the solution and use it as liquid nitrogen fertilizer for the growth of giant reed grass. Through an automated industrial planting system, carbon dioxide in the tail gas of the decarbonization tower is used as gas fertilizer, while the by-product of the carbon capture process is used as nitrogen fertilizer. The biomass co-firing module is used to process mature giant reeds into biomass fuel after natural drying and waste heat drying in boilers. This fuel replaces a portion of the coal used in power plant boilers for biomass co-firing power generation. Among them, the ammonia carbon capture module for carbon dioxide capture, the giant reed carbon fixation module for plant carbon fixation, and the biomass co-firing module for biomass energy co-firing are integrated into a triple carbon reduction system for carbon reduction and decarbonization, forming a closed-loop deep decarbonization system. While improving carbon capture efficiency, it achieves clean energy substitution and resource utilization, demonstrating significant carbon reduction potential and environmental and economic benefits.

7. The carbon reduction and decarbonization system for coal-fired power plants as described in claim 6, wherein, The ammonia-based carbon capture module is used for the first stage of carbon reduction. The module includes a decarbonization tower connected to the flue gas outlet of a power plant boiler via a flue gas pipeline. The decarbonization tower is connected to a slurry tank for storing ammonium bicarbonate solution. The slurry tank is connected to a neutralization water tank via a dedicated slurry pipeline. The neutralization water tank is connected to a water storage tank, a monitoring station, and a water pump. The water pump is connected to automatic sprinkler heads installed on the greenhouse. The top of the decarbonization tower is connected to the greenhouse via a gas-fertilizer pipeline, which is equipped with a gas-fertilizer control valve. In this process, flue gas from the coal-fired power plant enters the lower part of the decarbonization tower and forms convection currents with the ammonia solution flowing down from the top of the tower, achieving full contact and completing the chemical reaction. Carbon dioxide is absorbed and fixed by the ammonia solution, ultimately existing as ammonium bicarbonate solution and stored in the slurry tank. The saturated ammonium bicarbonate solution stored in the slurry tank is introduced into a neutralization tank through pipelines, and water from a storage tank is introduced into the neutralization tank to appropriately dilute the slurry. When the pH and conductivity readings at the monitoring station meet the fertilization standards, the water pump is turned on to introduce liquid nitrogen fertilizer into the greenhouse, which is then sprayed onto the giant reed using an automatic sprinkler system. The gas fertilizer control valve is opened to blow the exhaust gas (carbon dioxide) from the decarbonization tower into the greenhouse via a two-way fan as gas fertilizer for plant growth. Through this process, carbon dioxide is recovered and reused through flue gas waste utilization.

8. The carbon reduction and decarbonization system for coal-fired power plants as described in claim 6, wherein, The giant reed carbon fixation module is used for secondary carbon reduction. The module includes: a greenhouse, automatic sprinkler heads, a two-way fan, a CO2 concentration sensor, a controller, and an ammonia discharge valve. The greenhouse is equipped with a gas inlet, and the greenhouse and the power plant boiler are connected via an ammonia pipeline. The ammonia pipeline is equipped with an ammonia discharge valve, which is used to open the valve when the ammonia concentration inside the greenhouse is too high, allowing the ammonia to be introduced into the power plant boiler and mixed with air for combustion. Giant Napier grass is a highly efficient biological carbon-fixing plant with rapid growth and high carbon fixation capacity; it can absorb 20 to 30 tons of carbon per hectare per year. Planting giant Napier grass in greenhouses improves planting efficiency. To optimize the growth environment, the spraying volume and frequency of ammonium bicarbonate solution are systematically controlled to ensure effective nitrogen fertilizer supply at an appropriate concentration. Automatic sprinkler systems are used in the greenhouses where giant Napier grass is grown; these systems precisely apply nitrogen fertilizer to ensure the plant receives adequate nitrogen. The system ensures a sufficient supply of nutrients; bidirectional fans and air vents are installed at the top of the greenhouse; when it is necessary to apply gas fertilizer to the giant Napier grass, the gas fertilizer control valve is opened, and the bidirectional fans allow the gas fertilizer to flow into the greenhouse from the air vents; when the ammonia concentration in the greenhouse is too high, the ammonia discharge valve is opened and the gas fertilizer control valve is closed, and the bidirectional fans send the ammonia in the greenhouse into the power plant boiler to mix with air for combustion, which also has a denitrification effect; after the giant Napier grass matures, the system uses the equipped automatic harvester to efficiently and quickly harvest the mature giant Napier grass, reducing manual labor and improving harvesting efficiency.

9. The carbon reduction and decarbonization system for coal-fired power plants as described in claim 6, wherein, The biomass co-firing module is used for the third stage of carbon reduction. The biomass co-firing module includes: an automatic harvester, a drying chamber, an air duct, a fan, and a hay drying bin. Giant Napier grass has a high moisture content after harvesting, so it needs to be dried. Fresh giant Napier grass has a moisture content between 70% and 85%, and excessive moisture will affect its storage and combustion. The drying of giant Napier grass adopts a two-step drying method: natural sun exposure and boiler waste heat drying. First, the giant Napier grass is placed on a drying bed and exposed to the sun to reduce its moisture content. When the moisture content is reduced to about 45%, the giant Napier grass is placed in a drying bin. Boiler flue gas enters the air duct through a blower, enters the drying bin to complete the drying of the giant Napier grass, and then returns to the boiler flue gas duct. In the drying room, boiler waste heat is used to dry the giant Napier grass to a moisture content of 12%-15%. Giant Napier grass performs well in the field of biomass power generation. The dried giant Napier grass is used as biomass fuel in power plant boilers and co-fired with coal to generate electricity.

10. The carbon reduction and decarbonization system for coal-fired power plants as described in claim 6, wherein, The flue gas generated by the biomass co-firing module is returned to the decarbonization tower system of the ammonia carbon capture module through a dedicated pipeline, realizing closed-loop treatment of CO2, and the flue gas generated by combustion is returned to the decarbonization tower to realize carbon recycling.

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