A solid calcium-based carbon dioxide capture system coupled with a coal-fired boiler and method thereof

Abstract

A solid calcium-based carbon dioxide capture system and method coupled to a coal-fired boiler, belonging to the field of environmental protection technology. This system uses a fixed bed as the CO2 absorption reactor, employing solid CaO as the CO2 adsorbent. This eliminates the need for large amounts of water consumption and effectively avoids the problems associated with using liquid chemical reagents as CO2 adsorbents. Through fixed-bed technology, the system efficiently captures CO2 and regenerates the solid calcium-based adsorbent. Furthermore, it couples most of the heat from the high-temperature flue gas generated by the hot flue gas generator with the coal-fired boiler, promoting efficient energy recovery and significantly reducing the energy consumption for CO2 capture, providing an economically feasible strategy for achieving low-carbon goals. The technical solution provided by this invention enables the efficient capture of carbon dioxide from flue gas emitted by coal-fired power plants.

Description

Technical Field

[0001] This invention belongs to the field of environmental protection technology, specifically relating to a solid calcium-based carbon dioxide capture system coupled to a coal-fired boiler. Background Technology

[0002] Carbon dioxide capture technologies are categorized into pre-combustion capture, post-combustion capture, and oxy-fuel combustion. Pre-combustion capture and oxy-fuel combustion have significant limitations on coal-fired boilers and are difficult to apply to existing boilers. Post-combustion capture has less impact on coal-fired units, with liquid chemical absorption being one of the most mature and widely used technologies. It utilizes the chemical reaction between chemical reagents and carbon dioxide to separate CO2 from flue gas. This technology is largely mature and has been demonstrated on a small scale. However, this technology generally suffers from high energy consumption. Chemical absorption requires considerable energy during absorption and regeneration, especially the regeneration of the absorbent, which can lead to high overall energy consumption. Due to energy consumption and chemical usage, the operating cost of chemical absorption is relatively high, limiting its economic feasibility on a larger scale. The absorbent may have some environmental impact, such as emissions of volatile organic compounds and corrosion of equipment. Long-term operation may lead to equipment corrosion and blockage, increasing maintenance costs and operational complexity.

[0003] For example, patent document CN117839379A, published on April 9, 2024, discloses a high-pressure chemically coupled calcium-cycle carbon dioxide capture system and its application; this system is not suitable for coal-fired power units. Patent document CN114522533A, published on May 24, 2022, discloses a calcium-based heat carrier circulating flue gas carbon dioxide capture system and method. This system uses cyclone separation to achieve calcium-based circulating carbon dioxide capture, but the system introduces high-pressure air fluidized calcium-based absorbent, introducing air, increasing system energy consumption, and affecting the purity of captured carbon dioxide. Patent document CN114405247A, published on April 29, 2022, discloses a carbon dioxide capture system, which uses an air compressor for calcium-based carbon dioxide capture; this system is also not suitable for carbon dioxide capture in coal-fired power units.

[0004] Therefore, the present invention aims to develop an innovative CO2 capture method that reduces energy consumption, improves environmental compatibility, avoids equipment corrosion, and enhances system stability, in order to achieve better economic and environmental benefits. Summary of the Invention

[0005] The purpose of this invention is to provide a solid calcium-based carbon dioxide capture system coupled to a coal-fired boiler. This system uses a fixed bed as the reactor for absorbing CO2, and uses solid CaO as the CO2 adsorbent. It does not require the consumption of a large amount of water and can effectively avoid the problems of using liquid chemical reagents as CO2 adsorbents.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] The present invention provides a solid calcium-based carbon dioxide capture system coupled to a coal-fired boiler. The carbon dioxide capture system includes a high-temperature flue gas generator, a high-temperature regenerator assembly, a fixed bed assembly, a CO2 storage assembly, and a boiler assembly.

[0008] High-temperature flue gas generators are used to provide high-temperature flue gas for high-temperature regenerator components;

[0009] High-temperature regenerative furnace components are used to provide heat to the fixed-bed components and boiler components, respectively.

[0010] The fixed bed assembly is used to store CaCO3 particles, and after decomposing them into CO2 and CaO under the action of heat, the CO2 is sent to the CO2 storage assembly for storage. The CO2 storage assembly is used to provide heating energy for the high-temperature regenerative furnace assembly.

[0011] The boiler assembly is used to generate flue gas under the action of heat, and sends it to the fixed bed assembly to react with CaO to remove CO2 from the flue gas.

[0012] Furthermore, in a preferred embodiment, the above-mentioned high-temperature regenerative furnace assembly includes a first high-temperature regenerative furnace and a second high-temperature regenerative furnace.

[0013] The fixed bed assembly includes a first fixed bed, a second fixed bed, and a waste heat recovery device;

[0014] Both the first and second fixed beds are connected to the waste heat recovery device;

[0015] The first fixed bed is connected to the first high-temperature regenerator, and the second fixed bed is connected to the second high-temperature regenerator.

[0016] Furthermore, in a preferred embodiment, the CO2 storage component includes a first CO2 cooler, a CO2 booster fan, a second CO2 cooler, a CO2 booster device, and a CO2 storage tank;

[0017] Both the first CO2 cooler and the second CO2 cooler are connected to the fixed bed assembly;

[0018] The second CO2 cooler is connected to the CO2 storage tank via a CO2 booster device;

[0019] Both the CO2 storage tank and the first CO2 cooler are connected to the CO2 booster fan;

[0020] The CO2 booster fan is connected to the first high-temperature regenerator and the second high-temperature regenerator, respectively.

[0021] Furthermore, in a preferred embodiment, the boiler assembly includes a coal-fired boiler, a dust collector, and a desulfurization tower;

[0022] Coal-fired boilers are used to generate flue gas by means of heat, and then send it to a dust collector;

[0023] The dust collector removes dust from the flue gas and then sends it to the desulfurization tower for desulfurization.

[0024] The desulfurization tower sends the desulfurized flue gas to the fixed bed assembly.

[0025] Furthermore, in a preferred embodiment, the system is further provided with multiple valves.

[0026] Furthermore, in a preferred embodiment, carbon dioxide capture is achieved by opening and closing the aforementioned multiple valves.

[0027] Furthermore, in a preferred embodiment, the opening and closing of the aforementioned multiple valves is achieved through a control system.

[0028] This invention also provides a solid calcium-based carbon dioxide capture method coupled to a coal-fired boiler. The carbon dioxide capture method is based on a solid calcium-based carbon dioxide capture system coupled to a coal-fired boiler as described in any one of the above-mentioned methods. The carbon dioxide capture method specifically includes the following steps:

[0029] Step 1: Add solid CaCO3 particles to the first and second fixed beds respectively, and close all valves;

[0030] Step 2: Open the valves between the high-temperature flue gas generator and the first high-temperature regenerator, between the first high-temperature regenerator and the first fixed bed, the outlet of the first fixed bed, and between the CO2 booster and the CO2 storage tank. Start the high-temperature flue gas generator. The high-temperature flue gas heats the heat storage body in the first high-temperature regenerator. At the same time, the high-temperature flue gas heats the CaCO3 particles in the first fixed bed, causing them to decompose into CO2 and CaO. The CO2 is first cooled by the second CO2 cooler, and then pressurized by the CO2 booster and stored in the CO2 storage tank.

[0031] Step 3: Close the valves between the first high-temperature regenerator and the first fixed bed, and the valves at the outlet of the first fixed bed. Open the valves between the high-temperature flue gas generator and the second high-temperature regenerator, between the second high-temperature regenerator and the coal-fired boiler, between the desulfurization tower and the first fixed bed, and between the first fixed bed and the waste heat recovery device. Start the high-temperature flue gas generator. The high-temperature flue gas heats the heat storage body in the second high-temperature regenerator. The high-temperature flue gas enters the coal-fired boiler. After the heat of the flue gas is fully utilized, it enters the dust collector and the desulfurization tower, and then enters the first fixed bed. CO2 in the flue gas reacts with CaO to generate CaCO3. The flue gas after removing CO2 enters the waste heat recovery device.

[0032] Step 4: Open the valves between the CO2 storage tank and the CO2 booster fan, between the CO2 booster fan and the first high-temperature regenerator, between the first high-temperature regenerator and the first fixed bed, and at the outlet of the first fixed bed. CO2 is drawn from the CO2 storage tank, pressurized by the CO2 booster fan, and sent to the first high-temperature regenerator for heating. Then it enters the first fixed bed to heat the CaCO3 particles, which are decomposed into CO2 and CaO. A portion of the CO2 is cooled by the CO2 cooler and then pressurized by the CO2 booster fan before being sent to the CO2 storage tank. Another portion of the CO2 is cooled by the first CO2 cooler and then pressurized by the CO2 booster fan before being sent to the first high-temperature regenerator for heating. The high-temperature CO2 is then used to circulate and heat the CaCO3.

[0033] Step 5: After the system is running normally, the two regenerable furnaces operate alternately, one for heat storage and the other for releasing heat to heat CO2. The two fixed-bed reactors also operate alternately, one for absorbing CO2 in the flue gas and the other for decomposing CaCO3 to generate CO2 and CaO, thus realizing absorbent regeneration and carbon dioxide capture.

[0034] Furthermore, in a preferred embodiment, natural gas is used as fuel in the flue gas generator during the start-up phase. Once the system is running normally, the fuel in the flue gas generator can be replaced with coal or other fuels.

[0035] Furthermore, in a preferred embodiment, the above-described carbon dioxide capture method is applicable to the capture of carbon dioxide in flue gas emitted from coal-fired power plants.

[0036] The beneficial effects of this invention are as follows:

[0037] 1. This invention provides a solid calcium-based carbon dioxide capture system coupled to a coal-fired boiler. Through fixed-bed technology, it can efficiently capture CO2 and regenerate the solid calcium-based absorbent. Furthermore, it couples most of the heat from the high-temperature flue gas generated by the hot flue gas generator with the coal-fired boiler, which not only promotes efficient energy recovery but also significantly reduces the energy consumption for CO2 capture, providing an economically feasible strategy for achieving low-carbon goals.

[0038] 2. The present invention provides a solid calcium-based carbon dioxide capture system coupled to a coal-fired boiler, which is equipped with an independent high-temperature flue gas generator to provide a heat source for the decomposition of CaCO3 into CaO and CO2.

[0039] 3. The present invention provides a solid calcium-based carbon dioxide capture system coupled to a coal-fired boiler, which uses a regenerative furnace to store part of the heat of the high-temperature flue gas in the flue gas generator in a regenerator for heating CO2.

[0040] 4. The solid calcium-based carbon dioxide capture system coupled to a coal-fired boiler provided by the present invention uses a fixed bed as a reactor for CO2 absorption and CaO regeneration, which can ensure sufficient contact between CO2 and CaO powder, and the reaction efficiency can be guaranteed.

[0041] 5. The present invention provides a solid calcium-based carbon dioxide capture system coupled to a coal-fired boiler, which uses high-temperature CO2 to heat CaCO3 without introducing other gas components, ensuring that no other gases are produced in the decomposition of CaCO3 into CO2, and thus guaranteeing the purity of CO2.

[0042] 6. The present invention provides a solid calcium-based carbon dioxide capture system coupled with a coal-fired boiler, which uses high-temperature CO2 as part of the high-temperature CO2 at the outlet of the fixed bed, and uses it as a heat source for CaCO3 decomposition. The heat required for heating by the regenerator is small, which reduces the cost.

[0043] The technical solution provided by this invention can achieve efficient capture of carbon dioxide in the flue gas emitted by coal-fired power plants. Attached Figure Description

[0044] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0045] Figure 1 This is a schematic diagram of a solid calcium-based carbon dioxide capture system coupled to a coal-fired boiler, as described in this invention.

[0046] In this table, 1 represents a coal-fired boiler, 2 represents a dust collector, 3 represents a desulfurization tower, 4 represents the first fixed bed, 5 represents the second fixed bed, 6 represents the first high-temperature regenerator, 7 represents the second high-temperature regenerator, 8 represents a high-temperature flue gas generator, 9 represents a CO2 storage tank, 10 represents a waste heat recovery device, 11 represents the first CO2 cooler, 12 represents a CO2 booster fan, 13 represents the second CO2 cooler, 14 represents a CO2 booster device, and 15-28 and 30-31 represent valves. Detailed Implementation

[0047] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of this application with unnecessary detail.

[0048] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.

[0049] Implementation Method 1: This implementation method provides a solid calcium-based carbon dioxide capture system coupled to a coal-fired boiler. The system uses a fixed bed as the reactor for absorbing CO2, and uses solid CaO as the CO2 adsorbent. It does not require the consumption of a large amount of water and can effectively avoid the problem of using liquid chemical reagents as CO2 adsorbents.

[0050] The system includes a high-temperature flue gas generator 8, a high-temperature regenerator assembly, a fixed bed assembly, a CO2 storage assembly, and a boiler assembly;

[0051] The high-temperature flue gas generator 8 is used to provide high-temperature flue gas for the high-temperature regenerator components;

[0052] High-temperature regenerative furnace components are used to provide heat to the fixed-bed components and boiler components, respectively.

[0053] The fixed bed assembly is used to store CaCO3 particles, and after decomposing them into CO2 and CaO under the action of heat, the CO2 is sent to the CO2 storage assembly for storage. The CO2 storage assembly is used to provide heating energy for the high-temperature regenerative furnace assembly.

[0054] The boiler assembly is used to generate flue gas under the action of heat, and sends it to the fixed bed assembly to react with CaO to remove CO2 from the flue gas.

[0055] Implementation Method 2, see below Figure 1 This embodiment describes a specific example of a solid calcium-based carbon dioxide capture system coupled to a coal-fired boiler, as described in Embodiment 1.

[0056] The aforementioned high-temperature regenerator assembly includes a first high-temperature regenerator 6 and a second high-temperature regenerator 7.

[0057] The aforementioned fixed bed assembly includes a first fixed bed 4, a second fixed bed 5, and a waste heat recovery device 10;

[0058] The aforementioned CO2 storage assembly includes a first CO2 cooler 11, a CO2 booster fan 12, a second CO2 cooler 13, a CO2 booster device 14, and a CO2 storage tank 9;

[0059] The aforementioned boiler components include a coal-fired boiler 1, a dust collector 2, and a desulfurization tower 3;

[0060] like Figure 1 As shown, the specific structure of the carbon dioxide capture system is as follows:

[0061] The high-temperature flue gas generator 8 is connected to the first high-temperature regenerator 6 and the second high-temperature regenerator 7, respectively, to provide high-temperature flue gas, which heats the heat storage medium in the high-temperature regenerators. The first high-temperature regenerator 6 is connected to the first fixed bed 4 and the coal-fired boiler 1, respectively; the second high-temperature regenerator 7 is connected to the second fixed bed 5 and the coal-fired boiler 1, respectively. The two high-temperature regenerators can provide heat to the fixed beds, allowing the solid CaCO3 particles in the fixed beds to decompose into CO2 and CaO under the heat of the regenerators; they can also provide heat to the coal-fired boiler 1. In practical applications, the two high-temperature regenerators can operate alternately, with one used for heat storage and the other used for releasing heat to heat CO2. The two fixed-bed reactors also operate alternately, with one used to absorb CO2 from the flue gas and the other used to decompose CaCO3 to generate CO2 and CaO, thus achieving absorbent regeneration and carbon dioxide capture.

[0062] The outlets of both the first fixed bed 4 and the second fixed bed 5 are connected to the first CO2 cooler 11 and the second CO2 cooler 13, allowing the CO2 decomposed from the fixed beds to be cooled by the CO2 coolers. The second CO2 cooler 13 is connected to the CO2 storage tank 9 via a CO2 booster device 14, so that the CO2 pressurized by the CO2 booster device is sent to the CO2 storage tank 9 for storage. The CO2 storage tank 9 is located on the inlet CO2 replenishment pipeline of the CO2 booster fan 12. At the same time, the first CO2 cooler 11 is connected to the CO2 booster fan 12, so that the cooled CO2 can be directly sent to the CO2 booster fan 12.

[0063] The coal-fired boiler 1 is connected in sequence to the dust collector 2 and the desulfurization tower 3; the desulfurization tower 3 is connected to the first fixed bed 4 and the second fixed bed 5 respectively, and the outlets of the first fixed bed 4 and the second fixed bed 5 are connected to the waste heat recovery device 10 respectively; so that when the flue gas in the high-temperature regenerator enters the coal-fired boiler 1, the heat of the flue gas is fully utilized and then it enters the dust collector 2 and the desulfurization tower 3 for treatment, and then the flue gas is sent to the first fixed bed 4 or the second fixed bed 5. The CaO in the fixed bed reacts with the CO2 in the flue gas to generate CaCO3. The flue gas after removing CO2 enters the waste heat recovery device 10. Finally, the clean flue gas without CO2 is discharged into the atmosphere.

[0064] Furthermore, the CO2 booster fan 12 is connected to the first high-temperature regenerative furnace 6 and the second high-temperature regenerative furnace 7, respectively. This allows the CO2 decomposed from the fixed bed to reheat the CaCO3 particles without introducing other gaseous components, ensuring that no other gases are produced during the decomposition of CaCO3 into CO2, thus guaranteeing the purity of the CO2. It also allows the use of a portion of the high-temperature CO2 from the fixed bed outlet as a heat source for CaCO3 decomposition, requiring less heat for heating in the regenerative furnaces and reducing costs.

[0065] The carbon dioxide capture system proposed in this embodiment uses a fixed bed as the reactor for CO2 absorption and CaO regeneration, ensuring sufficient contact between CO2 and CaO powder and guaranteeing reaction efficiency. Simultaneously, the system includes an independent high-temperature flue gas generator to provide a heat source for the decomposition of CaCO3 into CaO and CO2. A regenerative furnace is used to store a portion of the heat from the high-temperature flue gas in the generator within a regenerator, which is then used to heat the CO2.

[0066] Implementation Method 3, see below Figure 1 This embodiment is described in detail below. It adds multiple valves to the above embodiment to achieve carbon dioxide capture by controlling the opening of the valves.

[0067] like Figure 1 As shown, valves 15 and 16 are respectively installed at the connection points between the CO2 booster fan 12 and the first high-temperature regenerator 6 and the second high-temperature regenerator 7; valves 17 and 18 are respectively installed at the connection points between the high-temperature flue gas generator 8 and the first high-temperature regenerator 6 and the second high-temperature regenerator 7; valves 19 and 20 are respectively installed at the connection points between the first high-temperature regenerator 6 and the second high-temperature regenerator 7 and the coal-fired boiler 1; valve 21 is installed between the first high-temperature regenerator 6 and the first fixed bed 4; and a valve is installed at the outlet of the first fixed bed 4. Valve 25 is installed; valve 22 is installed between the second high-temperature regenerator 7 and the second fixed bed 5, and valve 26 is installed at the outlet of the second fixed bed 5; valves 23 and 24 are installed between the desulfurization tower 3 and the first fixed bed 4 and the second fixed bed 5, respectively; valves 27 and 28 are installed between the first fixed bed 4, the second fixed bed 5 and the waste heat recovery device, respectively; valve 30 is installed between the CO2 booster equipment 14 and the CO2 storage tank 9; and valve 31 is installed between the CO2 storage tank 9 and the CO2 booster fan 12.

[0068] Implementation Method 4: This implementation method provides a carbon dioxide capture method based on a solid calcium-based carbon dioxide capture system coupled to a coal-fired boiler, as described in any of the above implementation methods. The method specifically includes the following steps:

[0069] Step 1: Add solid CaCO3 particles to the first and second fixed beds respectively, and close all valves.

[0070] Step 2: Open the valves between the high-temperature flue gas generator and the first high-temperature regenerator, between the first high-temperature regenerator and the first fixed bed, the outlet of the first fixed bed, and between the CO2 booster and the CO2 storage tank. Start the high-temperature flue gas generator. The high-temperature flue gas heats the heat storage body in the first high-temperature regenerator. At the same time, the high-temperature flue gas heats the CaCO3 particles in the first fixed bed, causing them to decompose into CO2 and CaO. The CO2 is first cooled by the second CO2 cooler, and then pressurized by the CO2 booster and stored in the CO2 storage tank.

[0071] Step 3: Close the valves between the first high-temperature regenerator and the first fixed bed, and the valves at the outlet of the first fixed bed. Open the valves between the high-temperature flue gas generator and the second high-temperature regenerator, between the second high-temperature regenerator and the coal-fired boiler, between the desulfurization tower and the first fixed bed, and between the first fixed bed and the waste heat recovery device. Start the high-temperature flue gas generator. The high-temperature flue gas heats the heat storage body in the second high-temperature regenerator. The high-temperature flue gas enters the coal-fired boiler. After the heat of the flue gas is fully utilized, it enters the dust collector and the desulfurization tower, and then enters the first fixed bed. CO2 in the flue gas reacts with CaO to generate CaCO3. The flue gas after removing CO2 enters the waste heat recovery device.

[0072] Step 4: Open the valves between the CO2 storage tank and the CO2 booster fan, between the CO2 booster fan and the first high-temperature regenerator, between the first high-temperature regenerator and the first fixed bed, and at the outlet of the first fixed bed. CO2 is drawn from the CO2 storage tank, pressurized by the CO2 booster fan, and then sent to the first high-temperature regenerator for heating. It then enters the first fixed bed to heat the CaCO3 particles, decomposing them into CO2 and CaO. A portion of the CO2 is cooled by the CO2 cooler and then pressurized by the CO2 booster equipment before being sent to the CO2 storage tank. A portion of the CaCO3... O2 After being cooled by the first CO2 cooler, the CO2 is pressurized by the CO2 booster fan and sent to the first high-temperature regenerator for heating. The high-temperature CO2 is then used to circulate and heat the CaCO3, ensuring the decomposition efficiency of CaCO3.

[0073] Step 5: After the system is running normally, the two regenerable furnaces operate alternately, one for heat storage and the other for releasing heat to heat CO2. The two fixed-bed reactors also operate alternately, one for absorbing CO2 in the flue gas and the other for decomposing CaCO3 to generate CO2 and CaO, thus realizing absorbent regeneration and carbon dioxide capture.

[0074] In practical applications, this implementation method is specifically as follows:

[0075] To prevent the introduction of other gases into the flue gas from decomposing CaCO3, natural gas is used as fuel in the flue gas generator 8 during the start-up phase. Once the system is running normally, the fuel in the flue gas generator 8 can be replaced with coal or other fuels.

[0076] Step 1: Add sufficient solid CaCO3 particles to the first fixed bed 4 and the second fixed bed 5 respectively, and keep all valves in the system closed. Open valves 18, 22, 26 and 30, start the high-temperature flue gas generator 8, and heat the heat storage body in the second high-temperature regenerator 7 with the high-temperature flue gas. At the same time, the high-temperature flue gas heats the CaCO3 particles in the second fixed bed 5, causing them to decompose into CO2 and CaO. The CO2 is first cooled by the CO2 cooler 13, and then pressurized by the CO2 booster equipment and stored in the CO2 storage tank 9. The CO2 storage tank 9 is set on the CO2 replenishment pipeline at the inlet of the CO2 booster fan.

[0077] Step Two: Close valves 18, 22, and 26; open valves 16, 19, 24, and 28; start the high-temperature flue gas generator. The generated high-temperature flue gas is used to heat the heat storage medium in the first high-temperature regenerator 6. Then, the flue gas enters the coal-fired boiler 1. After the heat of the flue gas is fully utilized, it enters the dust collector 2 and the desulfurization tower 3. The flue gas passes through the second fixed bed 5, where CO2 reacts with CaO to form CaCO3. The flue gas after removing CO2 enters the waste heat recovery device 10. Finally, the clean flue gas without CO2 is discharged into the atmosphere.

[0078] Step 3: Simultaneously, valves 15, 21, 25, and 31 are opened to draw CO2 from the CO2 storage tank 9. After being pressurized by the CO2 booster fan 12, CO2 is sent to the first high-temperature regenerative furnace 6 for heating. Then, it enters the first fixed bed 4 to heat the CaCO3 particles, decomposing them into CO2 and CaO. A portion of the CO2 is cooled by the CO2 cooler 13 and then pressurized by the CO2 booster fan 14 before being sent to the CO2 storage tank 9. Another portion of the CO2 is cooled by the CO2 cooler 11 and then pressurized by the CO2 booster fan 12 before being sent to the first high-temperature regenerative furnace 6 for heating. The high-temperature CO2 is then used to circulate and heat the CaCO3, ensuring the efficient decomposition of CaCO3.

[0079] Step 4: Once the system is running normally, the two regenerable furnaces operate alternately. When one is used for heat storage, the other is used for releasing heat to heat CO2. The two fixed-bed reactors also operate alternately, one for absorbing CO2 from the flue gas and the other for decomposing CaCO3 to generate CO2 and CaO, thus achieving absorbent regeneration and carbon dioxide capture.

[0080] It should be understood that, when used in this specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0081] It should also be understood that the terminology used in this application specification is for the purpose of describing particular embodiments only and is not intended to limit the application. As used in this application 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.

[0082] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0083] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0084] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A solid calcium-based carbon dioxide capture system coupled to a coal-fired boiler, characterized in that, Includes a high-temperature flue gas generator (8), a high-temperature regenerator assembly, a fixed bed assembly, a CO2 storage assembly, and a boiler assembly; The high-temperature flue gas generator (8) is used to provide high-temperature flue gas for the high-temperature regenerator assembly; High-temperature regenerative furnace components are used to provide heat to the fixed-bed components and boiler components, respectively. The boiler assembly is used to generate flue gas under the action of heat, and send it to the fixed bed assembly to react with CaO to remove CO2 from the flue gas; The fixed bed assembly is used to store CaCO3 particles, and after decomposing them into CO2 and CaO under the action of heat, the CO2 is sent to the CO2 storage assembly for storage. The CO2 storage assembly is used to provide heating energy for the high-temperature regenerative furnace assembly. The boiler components include a coal-fired boiler (1), a dust collector (2), and a desulfurization tower (3); A coal-fired boiler (1) is used to generate flue gas by means of heat and send it to a dust collector (2); The dust collector (2) sends the flue gas to the desulfurization tower (3) for desulfurization after dust removal treatment; The desulfurization tower (3) sends the desulfurized flue gas to the fixed bed assembly; The high-temperature regenerator assembly includes a first high-temperature regenerator (6) and a second high-temperature regenerator (7). The fixed bed assembly includes a first fixed bed (4), a second fixed bed (5), and a waste heat recovery device (10); The first fixed bed (4) and the second fixed bed (5) are both connected to the waste heat recovery device (10); the first fixed bed (4) is connected to the first high temperature heat storage furnace (6), and the second fixed bed (5) is connected to the second high temperature heat storage furnace (7); The two high-temperature regenerators provide heat to the fixed bed assembly, so that the solid CaCO3 particles in the fixed bed assembly decompose into CO2 and CaO under the heat of the regenerator, and also provide heat to the coal-fired boiler (1). The two high-temperature regenerators can operate alternately, with one used for heat storage and the other for releasing heat to heat CO2; the two fixed beds also operate alternately, with one used for absorbing CO2 from the flue gas and the other used for decomposing CaCO3 to generate CO2 and CaO, thus realizing absorbent regeneration and carbon dioxide capture. The CO2 storage assembly includes a first CO2 cooler (11), a CO2 booster fan (12), a second CO2 cooler (13), a CO2 booster device (14), and a CO2 storage tank (9). Both the first CO2 cooler (11) and the second CO2 cooler (13) are connected to the fixed bed assembly; The second CO2 cooler (13) is connected to the CO2 storage tank (9) via a CO2 booster device (14); The CO2 storage tank (9) and the first CO2 cooler (11) are both connected to the CO2 booster fan (12); The CO2 booster fan (12) is connected to the first high-temperature heat storage furnace (6) and the second high-temperature heat storage furnace (7), respectively.

2. The solid calcium-based carbon dioxide capture system coupled to a coal-fired boiler according to claim 1, characterized in that, The system is also equipped with multiple valves.

3. A solid calcium-based carbon dioxide capture system coupled to a coal-fired boiler according to claim 2, characterized in that, Carbon dioxide capture is achieved by opening and closing multiple valves.

4. A solid calcium-based carbon dioxide capture system coupled to a coal-fired boiler according to claim 2, characterized in that, The control system enables the opening and closing of multiple valves.

5. A carbon dioxide capture method implemented by a solid calcium-based carbon dioxide capture system coupled to a coal-fired boiler as described in any one of claims 1-4, characterized in that, The method is as follows: Step 1: Add solid CaCO3 particles to the first and second fixed beds respectively, and close all valves; Step 2: Open the valves between the high-temperature flue gas generator and the first high-temperature regenerator, between the first high-temperature regenerator and the first fixed bed, the outlet of the first fixed bed, and between the CO2 booster and the CO2 storage tank. Start the high-temperature flue gas generator. The high-temperature flue gas heats the heat storage body in the first high-temperature regenerator. At the same time, the high-temperature flue gas heats the CaCO3 particles in the first fixed bed, causing them to decompose into CO2 and CaO. The CO2 is first cooled by the second CO2 cooler, and then pressurized by the CO2 booster and stored in the CO2 storage tank. Step 3: Close the valves between the first high-temperature regenerator and the first fixed bed, and the valves at the outlet of the first fixed bed. Open the valves between the high-temperature flue gas generator and the second high-temperature regenerator, between the second high-temperature regenerator and the coal-fired boiler, between the desulfurization tower and the first fixed bed, and between the first fixed bed and the waste heat recovery device. Start the high-temperature flue gas generator. The high-temperature flue gas heats the heat storage body in the second high-temperature regenerator. The high-temperature flue gas enters the coal-fired boiler. After the heat of the flue gas is fully utilized, it enters the dust collector and the desulfurization tower, and then enters the first fixed bed. CO2 in the flue gas reacts with CaO to generate CaCO3. The flue gas after removing CO2 enters the waste heat recovery device. Step 4: Open the valves between the CO2 storage tank and the CO2 booster fan, between the CO2 booster fan and the first high-temperature regenerator, between the first high-temperature regenerator and the first fixed bed, and at the outlet of the first fixed bed. CO2 is drawn from the CO2 storage tank, pressurized by the CO2 booster fan, and sent to the first high-temperature regenerator for heating. Then it enters the first fixed bed to heat the CaCO3 particles, which are decomposed into CO2 and CaO. A portion of the CO2 is cooled by the CO2 cooler and then pressurized by the CO2 booster fan before being sent to the CO2 storage tank. Another portion of the CO2 is cooled by the first CO2 cooler and then pressurized by the CO2 booster fan before being sent to the first high-temperature regenerator for heating. The high-temperature CO2 is then used to circulate and heat the CaCO3. Step 5: After the system is running normally, the two regenerable furnaces operate alternately, one for heat storage and the other for releasing heat to heat CO2. The two fixed-bed reactors also operate alternately, one for absorbing CO2 in the flue gas and the other for decomposing CaCO3 to generate CO2 and CaO, thus realizing absorbent regeneration and carbon dioxide capture.

6. The solid calcium-based carbon dioxide capture method coupled to a coal-fired boiler according to claim 5, characterized in that, During the start-up phase, the flue gas generator uses natural gas as fuel. Once the system is running normally, the fuel in the flue gas generator can be replaced with coal or other fuels.

7. The solid calcium-based carbon dioxide capture method coupled to a coal-fired boiler according to claim 5, characterized in that, This method is suitable for capturing carbon dioxide in flue gas emitted from coal-fired power plants.

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