Carbon dioxide recovery system and method

Abstract

The invention discloses a carbon dioxide recovery system and method.The system comprises absorption towers independently arranged for all combustion equipment and used for absorbing carbon dioxide in flue gas; the flue gas pipeline is connected with the combustion equipment and the absorption tower; the regeneration towers are communicated with the absorption towers so as to recover carbon dioxide in the carbon dioxide-rich absorption liquid; the carbon dioxide-rich absorption liquid supply pipeline is connected with the absorption tower and the regeneration tower. A carbon dioxide-poor absorption liquid supply pipeline and a flow control component can be further included to ensure the concentration of the carbon dioxide-rich absorption liquid; the operation of the regeneration tower is optimized by a carbon dioxide flow measuring device and a heating medium flow control component. The absorption tower is arranged close to combustion equipment, the length of a large-pipe-diameter flue gas pipeline is shortened, the cost and the arrangement difficulty are reduced, the carbon dioxide recovery efficiency is effectively improved through reasonable control and recovery processes, and the device is suitable for multiple combustion equipment places such as chemical plants and thermal power plants.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon dioxide recovery, and in particular to a system and method suitable for recovering carbon dioxide from flue gas discharged from combustion equipment. Background Art

[0002] In the fields of modern chemical production and power supply, chemical plants and thermal power plants widely use combustion equipment to meet production needs. During the operation of these combustion equipment, flue gas containing a large amount of carbon dioxide will inevitably be produced. As a major greenhouse gas, excessive emissions of carbon dioxide have a very serious negative impact on the global climate environment. Therefore, the effective recovery and treatment of carbon dioxide emitted by combustion equipment has become a key issue that needs to be urgently addressed in the current industrial field.

[0003] There are two main traditional carbon dioxide recovery schemes, but both have obvious defects. First, each combustion device is equipped with an independent absorption tower and regeneration tower. Although this method can accurately treat the flue gas of each combustion device, it requires a large number of equipment, and the cost of purchasing, installing and maintaining these equipment is extremely high, which greatly increases the operating burden of the enterprise. Second, an absorption tower and a regeneration tower are uniformly set up in the factory, and each scattered combustion device is connected to the absorption tower through a pipeline to achieve centralized treatment of flue gas. However, in actual applications, it is found that when there are some large combustion equipment in the factory, the outer diameter of the flue gas pipeline can often reach several meters. When arranging such a large diameter pipeline in the factory, there will be many insurmountable difficulties. For example, it takes up a lot of space, which may conflict with other equipment and buildings in the factory, and it will also bring huge challenges in the installation, support and maintenance of the pipeline, making this centralized treatment method difficult to put into practice in many cases.

[0004] In summary, the existing carbon dioxide recovery scheme cannot meet the requirements of cost control and practical feasibility at the same time. There is an urgent need to develop a new system and method that can effectively recover carbon dioxide and effectively reduce equipment costs and pipeline layout difficulties. Summary of the invention

[0005] The purpose of the present invention is to provide a carbon dioxide recovery system and method, aiming to solve the problems of high equipment cost and difficult pipeline layout in the existing carbon dioxide recovery technology, and to provide an efficient and economical carbon dioxide recovery system and method to achieve effective recovery of carbon dioxide in the flue gas emitted by combustion equipment, while reducing the system construction and operation costs and improving the feasibility and practicality of the recovery process.

[0006] In order to achieve the above object, the present invention adopts the following technical solution: A carbon dioxide recovery system, comprising: An absorption tower independently provided for each combustion device, the absorption tower being used to allow the flue gas discharged from the combustion device to be in full contact with the absorption liquid, so as to absorb the carbon dioxide in the flue gas into the absorption liquid; A flue gas pipeline connecting each combustion device to the corresponding absorption tower; At least one regeneration tower, the regeneration tower being communicated with each absorption tower and used for recovering carbon dioxide from the carbon dioxide-rich absorption liquid in the absorption tower, and the number of the regeneration towers being less than the number of the absorption towers; A carbon dioxide-rich absorption liquid supply pipeline, which is respectively connected to the absorption tower and at least one regeneration tower and is used for transporting the carbon dioxide-rich absorption liquid from the absorption tower to one or more regeneration towers, wherein the distance between each combustion device and the corresponding absorption tower is shorter than the distance between each combustion device and the regeneration tower, and the outer diameter of the flue gas pipeline is larger than the outer diameter of the carbon dioxide-rich absorption liquid supply pipeline.

[0007] A further improvement of the present invention lies in that it further comprises: A carbon dioxide-lean absorption liquid supply pipeline for supplying carbon dioxide-lean absorption liquid to each absorption tower.

[0008] A further improvement of the present invention lies in that the carbon dioxide-lean absorption liquid is obtained by removing carbon dioxide from the carbon dioxide-rich absorption liquid by the regeneration tower and serves as the absorption liquid in contact with the flue gas in the absorption tower.

[0009] A further improvement of the present invention lies in that it further comprises: A flow control component for controlling the flow rate of the carbon dioxide-lean absorption liquid flowing through each carbon dioxide-lean absorption liquid supply pipeline to ensure that the carbon dioxide concentration in the carbon dioxide-rich absorption liquid flowing out of each absorption tower is not lower than a preset lower limit concentration.

[0010] A further improvement of the present invention lies in that it further comprises: A carbon dioxide flow rate measuring device for obtaining the carbon dioxide flow rate flowing into the regeneration tower.

[0011] A further improvement of the present invention lies in that it further comprises: A heat medium flow control component for controlling the heat medium flow rate supplied to the regeneration tower to heat the carbon dioxide-rich absorption liquid in the regeneration tower.

[0012] A further improvement of the present invention lies in that the heat medium flow control component controls the heat medium flow rate according to the value detected by the carbon dioxide flow rate measuring device.

[0013] A carbon dioxide recovery method, comprising the following steps: Introducing the flue gas discharged from each combustion device into the absorption tower provided for it, so that the flue gas is in full contact with the absorption liquid, thereby enabling the carbon dioxide in the flue gas to be absorbed by the absorption liquid; The carbon dioxide-rich absorption liquid is combined and sent into at least one regeneration tower to recover carbon dioxide, where the number of regeneration towers is at least one less than the number of absorption towers; The distance between each combustion device and the absorption tower provided for it is shorter than the distance between each combustion device and at least one regeneration tower; The outer diameter of the flue gas pipeline connecting each combustion device and the corresponding absorption tower is larger than the outer diameter of each pipeline for supplying the carbon dioxide-rich absorption liquid from the absorption tower to at least one regeneration tower.

[0014] A further improvement of the present invention is that it further includes: supplying lean carbon dioxide absorption liquid to each absorption tower through a lean carbon dioxide absorption liquid supply pipeline.

[0015] A further improvement of the present invention is that it further includes: obtaining the carbon dioxide flow rate flowing into the regeneration tower through a carbon dioxide flow rate measuring device.

[0016] Compared with the prior art, the present invention has at least the following beneficial technical effects: The carbon dioxide recovery system and method provided by the present invention have cost reduction: Since the carbon dioxide recovery system and method of the present invention use regeneration towers with a quantity less than that of absorption towers to treat the carbon dioxide-rich absorption liquid generated by multiple combustion devices, compared with the traditional method of equipping each combustion device with an absorption tower and a regeneration tower, the quantity of regeneration towers and related supporting equipment is significantly reduced, thereby greatly reducing the costs in aspects such as equipment purchase, installation, and maintenance. Pipeline layout optimization: The absorption towers are arranged near the combustion devices. Combining the differences in the outer diameters of the flue gas pipelines and the absorption liquid pipelines, the length of the large-diameter flue gas pipelines is shortened, the difficulty and complexity of pipeline layout are reduced, the pipeline construction cost and space occupation are reduced, and the rationality and compactness of the factory layout are improved. Recovery efficiency improvement: By ensuring the appropriate concentration of the carbon dioxide-rich absorption liquid through the flow control component, and optimizing the heating process according to the carbon dioxide flow rate by the heat medium flow control component, the recovery rate of carbon dioxide in the regeneration tower is effectively increased, ensuring the efficient and stable operation of the entire recovery system, and improving the recovery efficiency and quality of carbon dioxide. Application scope expansion: The carbon dioxide recovery system and method of the present invention are not only applicable to the carbon dioxide recovery of combustion devices in a single factory, but also can be applied to a complex composed of multiple adjacent factories. By centrally treating the flue gas of different factories, the overall cost is further reduced, providing a feasible carbon dioxide emission reduction solution for more enterprises, and having a wide application prospect and promotion value. Brief Description of the Drawings

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 It is a configuration diagram of the carbon dioxide recovery system according to Embodiment 1 of the present invention.

[0019] Figure 2 It is a layout diagram of the carbon dioxide recovery system according to Embodiment 1 of the present invention.

[0020] Figure 3 It is an improved layout diagram of the carbon dioxide recovery system according to Embodiment 1 of the present invention.

[0021] Figure 4 It is a configuration diagram of the carbon dioxide recovery system according to Embodiment 2 of the present invention.

[0022] Explanation of reference numerals: 100 - carbon dioxide recovery system, 1 - boiler, 2 - gas turbine, T1 - first absorption tower, T2 - second absorption tower, D1 - regeneration tower, D2 - rich-liquid / lean-liquid heat exchanger, D3 - carbon dioxide utilization device, D4 - compressor; B1 - first blower, B2 - second blower, C1 - first cooler, C2 - second cooler, M1 - first carbon dioxide flow measurement device, M2 - second carbon dioxide flow measurement device, M3 - rich carbon dioxide flow measurement device, V1 - first flow control valve, V2 - second flow control valve, V3 - heat medium flow control valve.

[0023] 11 - first pipeline, 21 - second pipeline, 12 - first outflow pipe, 22 - second outflow pipe, 20 - combined inflow pipe, 30 - outflow pipe, 31 - medium supply pipeline, 32 - medium discharge pipeline, 13 - first lean carbon dioxide absorption liquid supply pipe, 23 - second lean carbon dioxide absorption liquid supply pipe, P1 - first exhaust pipe, P2 - second exhaust pipe, 41 - carbon dioxide pipeline. Detailed embodiments

[0024] In the following, only some exemplary embodiments are briefly described. As those skilled in the art can recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the present invention. Therefore, the drawings and the description are considered to be exemplary in nature rather than restrictive.

[0025] 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 quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality of" means two or more unless otherwise specifically defined.

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

[0027] It should be understood that when used in this specification and the appended claims, the terms "comprises" and "comprising" indicate the presence of the described features, wholes, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

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

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

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

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

[0032] Embodiment 1 AsFigure 1 As shown in the figure, a carbon dioxide recovery system 100 provided by the present invention includes a plurality of absorption towers, namely a first absorption tower T1 and a second absorption tower T2. These absorption towers are respectively used to make the flue gas discharged from a plurality of combustion devices (such as a boiler 1 and a gas turbine 2) fully contact with the absorption liquid to absorb carbon dioxide in the flue gas. It also includes a regeneration tower D1 connected to the first absorption tower T1 and the second absorption tower T2.

[0033] The boiler 1 and the gas turbine 2 are respectively connected to the first absorption tower T1 and the second absorption tower T2 through a first pipeline 11 and a second pipeline 21. The first pipeline 11 and the second pipeline 21 are respectively equipped with a first blower B1, a second blower B2, a first cooler C1 and a second cooler C2. The first blower B1 and the second blower B2 can be installed on the inlet side of the cooler C1 and the second cooler C2.

[0034] The first absorption tower T1 and the second absorption tower T2 are respectively provided with a first outflow pipe 12 and a second outflow pipe 22. The carbon dioxide-rich absorption liquid flows out through the first outflow pipe 12 and the second outflow pipe 22, and is connected to the regeneration tower D1 through a combined inflow pipe 20, so that the carbon dioxide-rich absorption liquid flows into the regeneration tower D1 after being combined. Between the combination point of the combined inflow pipe 20 and the inlet of the regeneration tower D1, a rich-liquid / lean-liquid heat exchanger D2 is provided, which is used to make the carbon dioxide-rich absorption liquid in the combined inflow pipe 20 exchange heat with the carbon dioxide-lean absorption liquid in the outflow pipe 30 of the regeneration tower D1. The combined inflow pipe 20 can also be omitted, and the outflow pipe of each absorption tower can be directly connected to the regeneration tower D1. At this time, a carbon dioxide-rich absorption liquid heat exchanger needs to be provided to make the carbon dioxide-rich absorption liquid in the first outflow pipe 12 and the second outflow pipe 22 exchange heat with the carbon dioxide-lean absorption liquid in the first carbon dioxide-lean absorption liquid supply pipe 13 and the second carbon dioxide-lean absorption liquid supply pipe 23 respectively.

[0035] The first absorption tower T1 and the second absorption tower T2 are equipped with a first carbon dioxide-lean absorption liquid supply pipe 13 and a second carbon dioxide-lean absorption liquid supply pipe 23. The first carbon dioxide-lean absorption liquid supply pipe 13 and the second carbon dioxide-lean absorption liquid supply pipe 23 are connected to the outflow pipe 30 of the regeneration tower D1, and the carbon dioxide-lean absorption liquid is obtained by removing carbon dioxide from the carbon dioxide-rich absorption liquid in the regeneration tower D1.

[0036] The first absorption tower T1 and the second absorption tower T2 are also provided with a first exhaust pipe P1 and a second exhaust pipe P2, which are used to discharge the flue gas that has fully contacted the absorption liquid.

[0037] The regeneration tower D1 and the carbon dioxide utilization device D3 are connected by a carbon dioxide pipeline 41. The carbon dioxide pipeline 41 is used to transport the carbon dioxide recovered from the carbon dioxide-rich absorption liquid. A compressor D4 is equipped on the carbon dioxide pipeline 41 to increase the pressure of the carbon dioxide. In addition, a heat exchanger is provided in the regeneration tower D1, and a heating medium is supplied through a heating medium supply pipeline 31 to heat the carbon dioxide-rich absorption liquid. The heated heating medium flows out through a discharge pipeline 32.

[0038] Operation process: The flue gases discharged from the boiler 1 and the gas turbine 2 respectively pass through the first pipeline 11 and the second pipeline 21, are transported by the first blower B1 and the second blower B2, and are respectively cooled by the first cooler C1 and the second cooler C2, and then flow into the corresponding first absorption tower T1 and second absorption tower T2. The flue gases flowing into the first absorption tower T1 and the second absorption tower T2 are in full contact with the incoming lean carbon dioxide absorption liquid through the first lean carbon dioxide absorption liquid supply pipe 13 and the second lean carbon dioxide absorption liquid supply pipe 23, so that at least a part of the carbon dioxide in the flue gas is absorbed by the absorption liquid. The carbon dioxide-rich absorption liquid after absorbing carbon dioxide flows out from the first absorption tower T1 and the second absorption tower T2, and then flows out through the first outflow pipe 12 and the second outflow pipe 22 respectively.

[0039] After the carbon dioxide-rich absorption liquid flows out through the first outflow pipe 12 and the second outflow pipe 22 respectively and merges, it flows into the merging inflow pipe 20 of the regeneration tower D1, and then flows into the regeneration tower D1. In the regeneration tower D1, the carbon dioxide-rich absorption liquid releases carbon dioxide by being heated by a heating medium. The heating medium is supplied to the heat exchanger of the regeneration tower D1 by the pipeline 31, and the absorption liquid is transformed into a lean carbon dioxide absorption liquid. The heating medium that heats the carbon dioxide-rich absorption liquid flows out of the heat exchanger through the pipeline 32 after releasing heat.

[0040] The carbon dioxide released from the regeneration tower D1 is led out through the carbon dioxide pipeline 41, boosted by the compressor D4, and supplied to the device D3 that uses carbon dioxide. At the same time, the lean carbon dioxide absorption liquid flows out of the regeneration tower D1 through the outflow pipe 30, and is respectively distributed to the first lean carbon dioxide absorption liquid supply pipe 13 and the second lean carbon dioxide absorption liquid supply pipe 23, and is supplied to the first absorption tower T1 and the second absorption tower T2 as the absorption liquid.

[0041] Technical effect: In this embodiment 1, the carbon dioxide recovery system 100 is provided with only one regeneration tower D1, which is used to recover carbon dioxide from the carbon dioxide-rich absorption liquid that absorbs carbon dioxide from the flue gases respectively from multiple combustion devices (such as the boiler 1 and the gas turbine 2), and only one rich-liquid / lean-liquid heat exchanger D2 is provided. Compared with the scheme of equipping each combustion device with an absorption tower and a regeneration tower, the carbon dioxide recovery system 100 significantly reduces the cost of carbon dioxide recovery.

[0042] As Figure 2 shown, even if multiple combustion devices (such as boiler 1 and gas turbine 2) are scattered throughout the plant area, the first absorption tower T1 and the second absorption tower T2 equipped for each combustion device can be arranged near the combustion device. At this time, the distances L1 and L2 between the boiler 1, gas turbine 2 and their corresponding first absorption tower T1, second absorption tower T2 are shorter than the distances L11 and L22 between the regeneration tower D1 and the boiler 1, gas turbine 2. The outer diameters of the first flue gas pipes 11 and second pipes 21 connecting the combustion device and the first absorption tower T1, second absorption tower T2 are generally much larger than the outer diameters of the absorption liquid pipes (i.e., the first outflow pipe 12, second outflow pipe 22 and inflow pipe 20) connecting the first absorption tower T1, second absorption tower T2 and the regeneration tower D1. Arranging the first absorption tower T1 and the second absorption tower T2 near the combustion device can shorten the lengths of the large-diameter first flue gas pipes 11 and second pipes 21, which is beneficial to cost savings and optimization of the plant layout space.

[0043] In this Embodiment 1, the boiler 1 and gas turbine 2 are taken as examples of multiple combustion devices, but the combustion devices are not limited to these, and any device that emits carbon dioxide-containing flue gas due to combustion can be used. The number of combustion devices is not limited to two and can be more. In addition, in this Embodiment 1, the combustion devices are installed in the same plant area, but the present invention is not limited thereto. For example, as Figure 3 shown, in a complex where multiple factories F1, F2, F3, F4 are adjacent, a carbon dioxide recovery system 200 can also be set up. Among them, the absorption towers T01, T02, T03, T04 are arranged near each factory to absorb carbon dioxide in the flue gas emitted from each factory, and a regeneration tower D01 connected to each of the absorption towers T01 to T04 is set up. Different from the carbon dioxide recovery system 1 of Embodiment 1, the carbon dioxide recovery system 200 does not recover carbon dioxide from the flue gas emitted by multiple combustion devices in one factory, but recovers carbon dioxide from the flue gas emitted by a complex of multiple adjacent factories. By treating the flue gas of multiple factories of different companies, the cost of the carbon dioxide recovery system can be further reduced, enabling factories that were originally unable to install a carbon dioxide recovery system to also treat the flue gas emitted by combustion devices at low cost.

[0044] Embodiment 2 The carbon dioxide recovery system of this Embodiment 2 is formed by adding and optimizing a carbon dioxide recovery operation device on the basis of Embodiment 1.

[0045] As Figure 4As shown, in Embodiment 2 of the present invention, the first pipeline 11 and the second pipeline 21 of the carbon dioxide recovery system 100 are respectively provided with a first carbon dioxide flow measuring device M1 and a second carbon dioxide flow measuring device M2, which are used to detect the carbon dioxide flow contained in the flue gas between the first cooler C1, the second cooler C2 and the first absorption tower T1, the second absorption tower T2. The first carbon dioxide flow measuring device M1 and the second carbon dioxide flow measuring device M2 are composed of a flow sensor for detecting the flue gas flow and a concentration sensor for detecting the carbon dioxide concentration in the flue gas. By multiplying the values detected by the two sensors, the carbon dioxide flow flowing into each of the first absorption tower T1 and the second absorption tower T2 can be obtained. If the first blower B1 and the second blower B2 are respectively installed downstream of the first cooler C1 and the second cooler C2, the first carbon dioxide flow measuring device M1 and the second carbon dioxide flow measuring device M2 can be respectively arranged between the first blower B1, the second blower B2 and the first absorption tower T1, the second absorption tower T2.

[0046] CO 2 The lean absorption liquid supply pipes, namely the first lean carbon dioxide absorption liquid supply pipe 13 and the second lean carbon dioxide absorption liquid supply pipe 23, are respectively equipped with a first flow control valve V1 and a second flow control valve V2. These flow control valves are used to control the flow of the lean carbon dioxide absorption liquid flowing through the first lean carbon dioxide absorption liquid supply pipe 13 and the second lean carbon dioxide absorption liquid supply pipe 23, and the first flow control valve V1 and the second flow control valve V2 are respectively electrically interlocked with the first carbon dioxide flow measuring device M1 and the second carbon dioxide flow measuring device M2.

[0047] The inflow pipe 20 is provided with a rich carbon dioxide flow measuring device M3, which is used to obtain the carbon dioxide flow in the rich carbon dioxide absorption liquid. The rich carbon dioxide flow measuring device M3 can be composed of a flow sensor for detecting the flow of the rich carbon dioxide absorption liquid flowing through the inflow pipe 20 (i.e., the flow into the regeneration tower D1) and a concentration sensor for detecting the carbon dioxide concentration in the rich carbon dioxide absorption liquid. By multiplying the values detected by the two sensors, the rich carbon dioxide flow flowing into the regeneration tower D1 can be detected. The heating medium supply pipeline 31 is equipped with a heat medium flow control valve V3, which is used to control the flow of the heating medium supplied to the heat exchanger of the regeneration tower D1, and the heat medium flow control valve V3 is electrically interlocked with the rich carbon dioxide flow measuring device M3. Other configurations are the same as those in Embodiment 1.

[0048] Operation process: Similar to Embodiment 1, the flue gases discharged from the boiler 1 and the gas turbine 2 flow into the first absorption tower T1 and the second absorption tower T2 through the first pipeline 11 and the second pipeline 21 respectively. In this Embodiment 2, before the flue gases flow into the first absorption tower T1 and the second absorption tower T2, the first carbon dioxide flow measuring device M1 and the second carbon dioxide flow measuring device M2 detect the carbon dioxide flow contained in the flue gases respectively. After that, the carbon dioxide in the flue gases is absorbed into the absorption liquid in the first absorption tower T1 and the second absorption tower T2. After the carbon dioxide-rich absorption liquid recovers carbon dioxide in the regeneration tower D1, the operation of supplying the carbon dioxide-lean absorption liquid to the first absorption tower T1 and the second absorption tower T2 again is the same as that in Embodiment 1.

[0049] The amount of carbon dioxide that can be absorbed in the first absorption tower T1 and the second absorption tower T2 can be estimated based on the inflowing carbon dioxide flow and the flow of the components in the absorption liquid that can absorb carbon dioxide. Furthermore, the carbon dioxide concentration in the carbon dioxide-rich absorption liquid flowing out of the first absorption tower T1 and the second absorption tower T2 can be estimated. The relationship between the carbon dioxide flow flowing into the first absorption tower T1 and the second absorption tower T2 and the flow of the absorption components in the absorption liquid supplied to the first absorption tower T1 and the second absorption tower T2 is determined in advance to ensure that the carbon dioxide concentration in the carbon dioxide-rich absorption liquid flowing out of the first absorption tower T1 and the second absorption tower T2 is not lower than the preset lower limit concentration. If only the concentration of the absorption components is determined, the flow of the absorption components can be calculated by multiplying the flow of the absorption liquid by the concentration of the absorption components in the absorption liquid.

[0050] According to the above-mentioned correlation between the carbon dioxide flow and the absorption component flow, the first flow control valve V1 and the second flow control valve V2 control the flow of the absorption liquid supplied to the first absorption tower T1 and the second absorption tower T2 respectively based on the values detected by the first carbon dioxide flow measuring device M1 and the second carbon dioxide flow measuring device M2, so that the carbon dioxide concentration in the carbon dioxide-rich absorption liquid flowing out of the first absorption tower T1 and the second absorption tower T2 is not lower than the preset lower limit concentration.

[0051] Before the carbon dioxide-rich absorption liquid flows into the regeneration tower D1 through the inlet pipe 20, the carbon dioxide flow measuring device M3 detects the carbon dioxide flow in the carbon dioxide-rich absorption liquid. If the carbon dioxide flow flowing into the regeneration tower D1 is relatively high, it is necessary to increase the heat given to the carbon dioxide-rich absorption liquid in the regeneration tower D1, that is, increase the flow of the heating medium supplied to the heat exchanger of the regeneration tower. Therefore, the heat medium flow control valve V3 controls the flow of the heating medium supplied to the heat exchanger of the regeneration tower D1 according to the value detected by the carbon dioxide flow measuring device M3, realizing the optimized use of the heating medium.

[0052] Summary of technical effects: The carbon dioxide recovery system of the present invention effectively reduces the equipment cost by setting a regeneration tower with a quantity less than that of the absorption tower, and solves the cost problem of carbon dioxide treatment for multiple combustion devices.

[0053] Reasonably arrange the positions of the combustion devices, absorption towers and regeneration towers, and match pipes with different outer diameters, making the pipe layout more economical and efficient and reducing the layout difficulty.

[0054] Utilize flow control components and carbon dioxide flow measurement devices, etc., to ensure that the concentration of the carbon dioxide-rich absorption liquid is appropriate, improve the carbon dioxide recovery rate of the regeneration tower, optimize the use of the heating medium, and enhance the recovery efficiency and operation stability of the entire system.

[0055] The carbon dioxide recovery method of the present invention absorbs carbon dioxide by separately contacting the flue gas of the combustion device with the absorption liquid, then combines the carbon dioxide-rich absorption liquid to heat and recover carbon dioxide in the regeneration tower, and uses fewer regeneration towers, reducing the system cost, and has significant advantages compared with the traditional method of separately equipping an absorption tower and a regeneration tower for each combustion device.

Claims

1. A carbon dioxide recovery system, characterized in that: include: An absorption tower independently provided for each combustion device, the absorption tower being used to fully contact the flue gas discharged by the combustion device with the absorption liquid so as to absorb the carbon dioxide in the flue gas into the absorption liquid; Flue gas ducts connecting each combustion device to the corresponding absorption tower; At least one regeneration tower, the regeneration tower being in communication with each absorption tower and used for recovering carbon dioxide from the carbon dioxide-rich absorption liquid of the absorption tower, and the number of the regeneration towers is less than the number of the absorption towers; A carbon dioxide-rich absorption liquid supply pipeline is respectively connected to the absorption tower and at least one regeneration tower, and is used to transport the carbon dioxide-rich absorption liquid from the absorption tower to one or more regeneration towers, wherein the distance between each combustion device and the corresponding absorption tower is shorter than the distance between each combustion device and the regeneration tower, and the outer diameter of the flue gas pipeline is larger than the outer diameter of the carbon dioxide-rich absorption liquid supply pipeline.

2. A carbon dioxide recovery system according to claim 1, characterized in that: Also includes: The lean carbon dioxide absorption liquid supply pipeline is used to supply the lean carbon dioxide absorption liquid to each absorption tower.

3. A carbon dioxide recovery system according to claim 2, characterized in that: The lean carbon dioxide absorption liquid is obtained by removing carbon dioxide from the rich carbon dioxide absorption liquid in the regeneration tower, and serves as the absorption liquid in contact with the flue gas in the absorption tower.

4. A carbon dioxide recovery system according to claim 1, characterized in that: Also includes: The flow control component is used to control the flow through each carbon dioxide-lean absorption liquid supply pipeline to ensure that the carbon dioxide concentration in the carbon dioxide-rich absorption liquid flowing out of each absorption tower is not lower than a preset lower limit concentration.

5. A carbon dioxide recovery system according to claim 1, characterized in that: Also includes: The carbon dioxide flow measuring device is used to obtain the carbon dioxide flow flowing into the regeneration tower.

6. The carbon dioxide recovery system according to claim 5, characterized in that: Also includes: The heat medium flow control component is used to control the heat medium flow supplied to the regeneration tower to heat the carbon dioxide-rich absorption liquid in the regeneration tower.

7. The carbon dioxide recovery system according to claim 6, characterized in that: The heat medium flow control component controls the heat medium flow according to the value detected by the carbon dioxide flow measurement device.

8. A method for recovering carbon dioxide, characterized in that: The following steps are involved: The flue gas discharged from each combustion device is passed into the absorption tower provided therefor, so that the flue gas is fully in contact with the absorption liquid, so that the carbon dioxide in the flue gas is absorbed by the absorption liquid; Combining the carbon dioxide-rich absorption liquids and sending them to at least one regeneration tower to recover carbon dioxide, wherein the number of regeneration towers is at least one less than the number of absorption towers; The distance between each combustion device and the absorption tower provided therefor is shorter than the distance between each combustion device and at least one regeneration tower; The outer diameter of the flue gas duct connecting each combustion device and the corresponding absorption tower is larger than the outer diameter of each pipeline supplying the carbon dioxide-rich absorption liquid from the absorption tower to at least one regeneration tower.

9. A method for recovering carbon dioxide according to claim 8, characterized in that: Also includes: The carbon dioxide-lean absorption liquid is supplied to each absorption tower through the carbon dioxide-lean absorption liquid supply pipe.

10. A method for recovering carbon dioxide according to claim 8, characterized in that: Also includes: The carbon dioxide flow rate flowing into the regeneration tower is obtained by a carbon dioxide flow measuring device.

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