Carbon capture system for municipal solid waste incineration flue gas

Abstract

The utility model relates to a kind of carbon capture system and method of domestic waste incineration flue gas, belong to carbon emission reduction technical field.System includes flue gas purification unit, carbon capture unit and CO2 separation unit, rich amine liquid is respectively heated and raised temperature with high-temperature flue gas, lean amine liquid through first heat exchanger, second heat exchanger before flowing to analysis tower, high-temperature flue gas, lean amine liquid realizes heat exchange and cooling, realizes the heat energy integration and cascade utilization inside system, make full use of flue gas waste heat as CO2 analysis process heat source.High-temperature flue gas is carried out secondary cooling treatment after heat recovery by waste heat boiler, then remove various pollutants by flue gas purification unit, clean flue gas enters into absorption tower to make CO2 be absorbed by amine liquid, then clean flue gas is discharged through chimney.Rich CO2 amine liquid is released high-purity CO2 after being heated and analyzed in carbon capture unit, and is collected and utilized, to realize the CO2 efficient emission reduction and resource of waste incineration flue gas.

Description

Technical Field

[0001] This utility model belongs to the field of carbon emission reduction technology and relates to a carbon capture system for flue gas from municipal solid waste incineration. Background Technology

[0002] Promoting a green and low-carbon transformation has long been a broad consensus in the international community. Against this backdrop, various industries have taken active steps to deepen carbon emission reduction efforts, striving to contribute to mitigating climate change. Municipal solid waste incineration, as a key method of urban solid waste treatment, plays an irreplaceable role in achieving "reduction, resource recovery, and harmless disposal" of waste. However, it cannot be ignored that this process generates a large amount of carbon dioxide. With the official launch of the national carbon emission trading market, the municipal solid waste incineration industry is highly likely to be further included in the scope of emission control, which means that the industry faces enormous pressure to reduce carbon emissions.

[0003] However, the application of carbon capture technology in the municipal solid waste incineration industry is still in its early stages, and mature and applicable solutions are currently lacking. Compared with flue gas from conventional coal-fired power plants, flue gas from municipal solid waste incineration has many significant characteristics, which bring multiple technical challenges to the application of carbon capture technology.

[0004] Firstly, the CO2 concentration in flue gas from municipal solid waste incineration is low, while the moisture and oxygen content are high. Typically, the CO2 concentration in flue gas from municipal solid waste incineration is between 8% and 12%, a significantly lower figure than that of coal-fired flue gas. This lower CO2 concentration leads to a substantial increase in energy consumption per unit of CO2 capture. Because to capture the same amount of carbon dioxide, a larger volume of flue gas needs to be processed under lower concentration conditions, which undoubtedly increases the difficulty and energy consumption of the carbon capture process. Simultaneously, the high moisture and oxygen content also negatively impacts the carbon capture process, potentially affecting the performance and stability of the capture equipment, further increasing the difficulty of applying the technology.

[0005] Secondly, the flue gas temperature from municipal solid waste incineration is relatively high, generally exceeding 140℃. If this high-temperature flue gas is directly introduced into an amine-based carbon capture system, the system's specific temperature requirements necessitate additional cooling units. These additional cooling units not only complicate the entire carbon capture system, increasing the number of devices and floor space required, but also significantly raise energy consumption and operating costs. Furthermore, the cooling process may introduce other problems, such as low cooling efficiency and difficulties in selecting and using the cooling medium, all of which pose significant challenges to the practical application of the technology.

[0006] Therefore, directly applying mature carbon capture technologies from other industries to the waste incineration sector will lead to a series of problems. The primary issue is system instability. Due to the unique properties of flue gas from municipal solid waste incineration, technologies from other industries may not be well-suited, resulting in frequent equipment malfunctions and disrupting normal carbon capture operations. Simultaneously, energy and material consumption will remain high, significantly increasing investment and operating costs, which severely restricts the large-scale application of this technology in the waste incineration industry. Therefore, developing carbon capture technologies suitable for the municipal solid waste incineration industry is urgently needed. Only by overcoming these technical challenges can the green and low-carbon transformation of the municipal solid waste incineration industry be achieved.

[0007] Therefore, there is an urgent need for a carbon capture system and process that can adapt to the characteristics of flue gas from municipal solid waste incineration and achieve "high-efficiency absorption, low-consumption operation, and long-term stable operation" to fill the technological gap in this field and help the waste incineration industry achieve green and low-carbon transformation. Utility Model Content

[0008] In view of this, the purpose of this utility model is to provide a carbon capture system for flue gas from municipal solid waste incineration, which does not require additional cooling units, simplifies the system structure, and achieves efficient absorption and stable operation with low energy consumption and low cost.

[0009] To achieve the above objectives, this utility model provides the following technical solution: A carbon capture system for flue gas from municipal solid waste incineration includes a flue gas purification unit, a carbon capture unit, and a CO2 separation unit; The flue gas purification unit includes a first heat exchanger and an absorption tower connected in sequence; the first heat exchanger is connected to the high-temperature flue gas outlet of the waste heat boiler. The carbon capture unit includes an absorption subunit and a desorption / regeneration subunit, wherein the absorption subunit includes the absorption tower shared with the flue gas purification unit; the absorption tower and the desorption / regeneration subunit are connected by an amine liquid circulation pipeline through a rich amine channel and a poor amine channel; the CO2 gas outlet of the desorption / regeneration subunit is connected to the CO2 separation unit, and the rich amine liquid that reacts in the desorption / regeneration subunit releases CO2 gas, which is output and stored in the CO2 separation unit; The carbon capture unit further includes a second heat exchanger. The rich amine channel is connected in sequence to the low-temperature end of the second heat exchanger and the first heat exchanger. The lean amine channel is connected to the high-temperature end of the second heat exchanger. The rich amine channel exchanges heat with the high-temperature flue gas through the first heat exchanger, and the rich amine channel exchanges heat with the lean amine channel through the second heat exchanger.

[0010] Optionally, the flue gas purification unit further includes a bag filter connected to the outlet end of the first heat exchanger.

[0011] Optionally, the flue gas purification unit further includes a water washing and cooling tower, which is connected between the bag filter and the absorption tower.

[0012] Optionally, the flue gas outlet of the absorption tower is connected to a chimney.

[0013] Optionally, the analytical regeneration subunit includes an analytical tower.

[0014] Optionally, the CO2 separation unit includes a condensation separation subunit connected to the CO2 gas outlet of the analytical regeneration subunit.

[0015] Optionally, the CO2 separation unit may further include a storage subunit connected to the outlet end of the condensation separation subunit.

[0016] The beneficial effects of this utility model are as follows: This invention provides a highly efficient carbon capture system and method for municipal solid waste incineration flue gas. It eliminates the need for additional cooling units, simplifying the system configuration and achieving efficient absorption and stable operation with low energy consumption and low cost. This invention combines mature waste incineration flue gas purification technology with amine-based carbon capture technology, forming an integrated solution encompassing energy recovery, pollutant control, and efficient carbon dioxide capture. This achieves efficient synergy and tiered energy utilization among the various treatment units, improving the overall system's economic efficiency and operational stability. Building upon the ultra-low emissions of pollutants from conventional municipal solid waste incineration, it further enables efficient CO2 capture and resource recovery from the flue gas, truly bringing waste incineration towards near-zero emissions, demonstrating significant environmental benefits and social significance. Specifically, this invention fully utilizes the waste heat of flue gas as a heat source for the CO2 desorption process through internal thermal energy integration and cascade utilization. On the one hand, it uses high-temperature flue gas to heat the amine-rich liquid, reducing the external heating source requirement for the desorption process. On the other hand, it recovers waste heat within the system through heat exchange between the lean and rich amine liquids, significantly reducing the operating energy consumption of the carbon capture unit and solving the key bottleneck of high energy consumption in traditional amine-based carbon capture systems. The carbon capture system of this invention adopts a stepped cooling, multi-stage purification, and amine regeneration process, possessing good load adaptability and operational flexibility. It can adapt to the large fluctuations in the composition of waste incineration flue gas, ensuring the long-term stable operation of the carbon capture system.

[0017] This invention achieves efficient CO2 capture while obtaining high-purity CO2 product gas through analysis, condensation and separation, providing possibilities for subsequent resource utilization (such as chemical raw materials, carbon utilization technology, etc.), realizing the transformation from "waste gas treatment" to "carbon resource recovery", which has both environmental benefits and potential economic value.

[0018] Other advantages, objectives, and features of this invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination and study, or may be learned from practice of this invention. The objectives and other advantages of this invention can be realized and obtained through the following description. Attached Figure Description

[0019] To make the objectives, technical solutions, and advantages of this utility model clearer, the preferred embodiments of this utility model will be described in detail below with reference to the accompanying drawings, wherein: Figure 1 This is a schematic diagram of the overall carbon capture system of this utility model; Figure 2 This is a schematic diagram of a flue gas purification unit; Figure 3 This is a schematic diagram of a carbon capture unit; Figure 4 This is a schematic diagram of a CO2 separation unit.

[0020] Figure label: 1. Flue gas purification unit, 11. Waste heat boiler, 12. First heat exchanger, 13. Bag filter, 14. Water washing cooling tower, 15. Absorption tower, 16. Chimney, 2. Carbon capture unit, 21. Desorption tower, 22. Second heat exchanger, 23. Rich amine channel, 24. Poor amine channel, 3. CO2 separation unit, 31. Condensation separation subunit, 32. Storage subunit. Detailed Implementation

[0021] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this utility model. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0022] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the present invention. To better illustrate the embodiments of the present invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0023] In the accompanying drawings of this utility model, the same or similar reference numerals correspond to the same or similar components. In the description of this utility model, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting this utility model. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0024] Please see Figures 1-4 This invention relates to a carbon capture system for municipal solid waste incineration flue gas, comprising a flue gas purification unit 1, a carbon capture unit 2, and a CO2 separation unit 3. The purpose of this carbon capture system is as follows: the high-temperature flue gas generated during incineration first recovers heat through a waste heat boiler 11; then it undergoes cooling treatment to reach a suitable temperature; subsequently, it passes through the flue gas purification unit 1 to deeply remove various pollutants; the purified flue gas enters an amine absorption tower 15, where CO2 is selectively absorbed by the amine liquid, and then the clean flue gas is discharged through a chimney 16. The CO2-rich amine liquid enters the carbon capture unit 2, where it is heated and decomposed to release high-purity CO2, which is then separated, collected, and utilized by the CO2 separation unit 3, thereby achieving efficient carbon dioxide emission reduction and resource recovery from waste incineration flue gas.

[0025] The flue gas purification unit 1 is a pretreatment stage that removes interfering substances such as sulfides, nitrates, and dust, and absorbs CO2. The absorbed flue gas is then discharged into the atmosphere. The flue gas purification unit 1 includes a first heat exchanger 12, a bag filter 13, a water washing cooling tower 14, an absorption tower 15, and a chimney 16, which are connected in sequence along the flue gas flow direction. The first heat exchanger 12 is connected to the high-temperature flue gas outlet of the waste heat boiler 11.

[0026] Specifically, the flue gas purification unit 1 receives high-temperature flue gas discharged from the outlet of the waste heat boiler 11, typically exceeding 170℃ (approximately 185-195℃), requiring two-stage cooling processes. The first cooling process lowers the temperature above 170℃ to a level suitable for entering the bag filter 13, generally around 140℃ (approximately 135-145℃). In this innovative application, a heat exchanger is used to cool the flue gas from above 170℃ to around 140℃, utilizing the released heat in the carbon capture unit 2. After the first cooling, the flue gas passes through the bag filter 13 for dust removal, ensuring the cleanliness of the downstream flue gas; the dust content is generally no higher than 5-30 mg / Nm³. 3The flue gas temperature after passing through bag filter 13 is approximately 130-140℃. The flue gas undergoes a second cooling process to further reduce its temperature to the suitable range required by the carbon capture unit, typically 40-60℃. This second cooling uses a water scrubbing tower, which quickly and accurately lowers the flue gas temperature and removes acidic gases, ensuring the purity of the flue gas entering the carbon capture unit 2. The cooled flue gas then enters the CO2 absorption tower 15, where it mixes with amine solution. The amine solution fully absorbs the CO2 in the flue gas. After the CO2 is completely absorbed, the flue gas is discharged into the atmosphere through chimney 16 at a temperature of approximately 50-60℃.

[0027] Carbon capture unit 2 functions to efficiently separate and enrich CO2 from the clean flue gas from flue gas purification unit 1, thereby achieving carbon emission reduction. Carbon capture unit 2 includes an absorption subunit and a desorption / regeneration subunit, supplemented by an amine liquid circulation and heat exchange system. The core equipment of the absorption subunit is the absorption tower 15, shared with flue gas purification unit 1, which provides the CO2 absorption site. The flue gas with absorbed CO2 is discharged from the top of the absorption tower 15; while the amine liquid (referred to as rich amine liquid) that has absorbed CO2 is discharged from the bottom of the absorption tower 15, at a temperature of approximately 55-65℃. An amine liquid circulation pipeline is formed between the absorption tower 15 and the desorption / regeneration subunit via a rich amine channel 23 and a lean amine channel 24.

[0028] In this process, this invention innovatively proposes a two-stage heating process to raise the temperature of the rich amine solution to meet the temperature requirements for CO2 release reaction. The first stage of heating serves as preheating of the rich amine solution. A second heat exchanger 22 is installed on the amine solution circulation pipeline. The rich amine channel 23 is sequentially connected to the low-temperature end of the second heat exchanger 22 and the first heat exchanger 12; the lean amine channel 24 is connected to the high-temperature end of the second heat exchanger 22. The low-temperature medium of the second heat exchanger 22 is the rich amine solution that has absorbed CO2 and is discharged from the absorption tower 15; the high-temperature medium is the lean amine solution that has undergone CO2 desorption and is being circulated back to the absorption tower 15. After heat exchange between the rich and lean amine solutions, the temperature rises to approximately 80-90°C, but this is still not sufficient to meet the temperature requirements for CO2 release from the rich amine solution. Therefore, a second heating process is required for the preheated rich amine solution. The secondary heating of the rich amine solution utilizes the high-temperature flue gas temperature at the outlet of the waste heat boiler 11 in the flue gas purification unit 1. The rich amine solution is used as a low-temperature medium and introduced into the first heat exchanger 12 at the outlet of the waste heat boiler 11. The rich amine solution is heated by the high-temperature flue gas at the outlet of the waste heat boiler 11 to the reaction temperature for CO2 release, which is approximately 105-115℃. The rich amine solution that has reached the CO2 release reaction temperature is then sent to the desorption and regeneration subunit.

[0029] The core equipment of the desorption and regeneration subunit is the desorption tower 21. Inside the desorption tower, the amine-rich liquid has been heated by the high-temperature flue gas to the temperature condition where the chemical bonds between the amine-rich liquid and CO2 are broken, thereby releasing high-purity CO2 gas. The purified flue gas comes into contact with the lean amine liquid in the tower. During this process, the amine liquid and CO2 in the flue gas undergo a selective chemical reaction to form weakly bonded compounds, thereby transferring CO2 from the flue gas phase to the liquid phase for capture. The amine liquid that has released CO2 (i.e., the lean amine liquid) is sent to the absorption tower 15. During its passage through the lean amine channel 24, it is cooled by heat exchange with the amine-rich liquid at the second heat exchanger 22, reaching the reaction temperature conditions for CO2 absorption before entering the absorption tower 15, at which point the temperature is approximately 75-85℃. The absorption tower 15 realizes the CO2 capture process, including CO2 absorption and release, through amine liquid circulation and heat exchange.

[0030] The desorbed CO2 gas and water vapor mixture is discharged from the desorption tower and enters the CO2 separation unit 3. The CO2 separation unit 3 includes a condensation separation subunit 31 connected to the CO2 gas outlet of the desorption tower 21. The outlet end of the condensation separation subunit 31 is connected to a storage subunit 32 to collect and store the CO2 gas. The core equipment of the CO2 separation unit 3 is mainly a condenser, which cools the CO2 gas to a temperature of approximately 35-45°C, and after separation by the separator, high-purity CO2 product gas is obtained.

[0031] The purpose of this carbon capture system is as follows: The high-temperature flue gas generated from incineration first recovers heat through a waste heat boiler 11; then it undergoes cooling treatment to reach a suitable temperature; subsequently, it passes through a flue gas purification unit 1 to deeply remove various pollutants; the purified flue gas enters an amine absorption tower 15, where CO2 is selectively absorbed by the amine liquid, and then the clean flue gas is discharged through a chimney 16. The CO2-rich amine liquid enters the carbon capture unit 2, where it is heated and decomposed to release high-purity CO2, which is then separated, collected, and utilized by the CO2 separation unit 3, thereby achieving efficient carbon dioxide emission reduction and resource recovery from waste incineration flue gas.

[0032] A carbon capture method for the aforementioned carbon capture system specifically includes the following steps: Flue gas from municipal solid waste incineration absorbs heat in a waste heat boiler 11 and is then discharged to the first heat exchanger 12 of the flue gas purification unit 1 for heat exchange. After the high-temperature flue gas temperature decreases, it passes through a bag filter 13 connected to the outlet of the first heat exchanger 12 for desulfurization, denitrification, and dust removal. The flue gas then enters a water washing and cooling tower 14 for secondary cooling, removing acidic gases. After secondary cooling in the water washing and cooling tower 14, the flue gas enters an absorption tower 15 and mixes with a lean amine solution. During this process, the amine solution undergoes a selective chemical reaction with CO2 in the flue gas, forming a weakly bound compound, thereby transferring CO2 from the flue gas phase to the liquid phase for capture. The flue gas with absorbed CO2 is discharged from the top of the absorption tower 15, while the CO2-rich amine solution is discharged from the bottom of the absorption tower 15 into the amine solution circulation pipeline.

[0033] As the rich amine liquid flows through the rich amine channel 23 to the desorption and regeneration subunit, it undergoes two stages of heating: it exchanges heat with the lean amine liquid through the second heat exchanger 22 and then exchanges heat with the high-temperature flue gas through the first heat exchanger 12 to heat the rich amine liquid to the reaction temperature for releasing CO2. After reaching the CO2 release reaction temperature, the rich amine liquid releases CO2 gas after passing through the desorption and regeneration subunit. As the lean amine liquid that has released CO2 is sent back to the absorption tower 15 through the lean amine channel 24, it exchanges heat with the rich amine liquid through the second heat exchanger 22.

[0034] The CO2 gas outlet of the analysis regeneration subunit is connected to a condenser, a separator, and a storage subunit 32. The high-purity CO2 gas obtained after cooling by the condenser and separation by the separator is stored in the storage subunit 32 for easy use.

[0035] This invention provides a high-efficiency carbon capture system and method for municipal solid waste incineration flue gas. It eliminates the need for additional cooling units, simplifying the system configuration and achieving efficient absorption and stable operation with low energy consumption and low cost. This invention combines mature waste incineration flue gas purification technology with amine-based carbon capture technology, forming an integrated solution encompassing energy recovery, pollutant control, and efficient carbon dioxide capture. This achieves efficient synergy and tiered energy utilization among the various treatment units, improving the overall system's economic efficiency and operational stability. Building upon the ultra-low emissions of pollutants from conventional municipal solid waste incineration, it further enables efficient CO2 capture and resource recovery from the flue gas, truly bringing waste incineration towards near-zero emissions, demonstrating significant environmental benefits and social significance.

[0036] Specifically, this invention fully utilizes the waste heat of flue gas as a heat source for the CO2 desorption process through internal thermal energy integration and tiered utilization. On the one hand, high-temperature flue gas is used to heat the amine-rich liquid, reducing the external heating source requirement for the desorption process. On the other hand, waste heat within the system is recovered through heat exchange between the lean and rich amine liquids, significantly reducing the operating energy consumption of carbon capture unit 2 and solving the key bottleneck of high energy consumption in traditional amine-based carbon capture systems. The carbon capture system of this invention adopts a stepped cooling, multi-stage purification, and amine regeneration process, possessing good load adaptability and operational flexibility. It can adapt to the large fluctuations in the composition of waste incineration flue gas, ensuring the long-term stable operation of the carbon capture system.

[0037] This invention achieves efficient CO2 capture while obtaining high-purity CO2 product gas through analysis, condensation and separation, providing possibilities for subsequent resource utilization (such as chemical raw materials, carbon utilization technology, etc.), realizing the transformation from "waste gas treatment" to "carbon resource recovery", which has both environmental benefits and potential economic value.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of this technical solution, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A carbon capture system for flue gas from municipal solid waste incineration, characterized in that: It includes a flue gas purification unit (1), a carbon capture unit (2), and a CO2 separation unit (3); The flue gas purification unit (1) includes a first heat exchanger (12) and an absorption tower (15) connected in sequence; the first heat exchanger (12) is connected to the high-temperature flue gas outlet of the waste heat boiler (11); The carbon capture unit (2) includes an absorption subunit and a desorption and regeneration subunit, wherein the absorption subunit includes the absorption tower (15) shared with the flue gas purification unit (1); the absorption tower (15) and the desorption and regeneration subunit are connected by an amine liquid circulation pipeline through an amine-rich channel (23) and an amine-poor channel (24); the CO2 gas outlet of the desorption and regeneration subunit is connected to the CO2 separation unit (3), and the amine-rich liquid that reacts in the desorption and regeneration subunit releases CO2 gas, which is output and stored in the CO2 separation unit (3); The carbon capture unit (2) further includes a second heat exchanger (22). The rich amine channel (23) is connected in sequence to the low-temperature end of the second heat exchanger (22) and the first heat exchanger (12). The poor amine channel (24) is connected to the high-temperature end of the second heat exchanger (22). The rich amine channel (23) exchanges heat with the high-temperature flue gas through the first heat exchanger (12). The rich amine channel (23) exchanges heat with the poor amine channel (24) through the second heat exchanger (22).

2. The carbon capture system for municipal solid waste incineration flue gas according to claim 1, characterized in that: The flue gas purification unit (1) also includes a bag filter (13) connected to the outlet end of the first heat exchanger (12).

3. The carbon capture system for municipal solid waste incineration flue gas according to claim 2, characterized in that: The flue gas purification unit (1) also includes a water washing cooling tower (14), which is connected between the bag filter (13) and the absorption tower (15).

4. The carbon capture system for municipal solid waste incineration flue gas according to claim 1, characterized in that: The flue gas outlet of the absorption tower (15) is connected to the chimney (16).

5. The carbon capture system for municipal solid waste incineration flue gas according to claim 1, characterized in that: The analytical regeneration subunit includes an analytical tower (21).

6. The carbon capture system for municipal solid waste incineration flue gas according to claim 1, characterized in that: The CO2 separation unit (3) includes a condensation separation subunit (31) connected to the CO2 gas outlet of the analytical regeneration subunit.

7. The carbon capture system for municipal solid waste incineration flue gas according to claim 6, characterized in that: The CO2 separation unit (3) also includes a storage subunit (32) connected to the outlet end of the condensation separation subunit (31).

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