Self-adaptive variable load working condition circulation-partition absorption CO2 capture strengthening device and flexible regulation and control method of self-adaptive variable load working condition circulation-partition absorption CO2 capture strengthening device

Abstract

The invention discloses a self-adaptive variable-load working condition cycle-partition absorption CO2 capture intensifying device and a flexible regulation and control method. The device comprises a demister, a second-stage liquid distributor, a second-stage packing layer, a second-stage adjustable gas rising cap, a second-stage liquid collector, a first-stage liquid distributor, a first-stage packing layer, a first-stage adjustable gas rising cap and a first-stage liquid collector from top to bottom, and graded circulation of an absorbent is realized through a second-stage liquid storage tank, a second-stage circulating pump, a first-stage liquid storage tank and a first-stage circulating pump. A circulation-partition absorption structure is adopted, flue gas redistribution is achieved through the adjustable gas rising cap, and the opening and closing proportion of the sealing cover is dynamically adjusted in combination with a flue gas flow rate regulation and control model based on load prediction, so that the carbon capture efficiency of the device is kept stable under the variable load working condition; the problem that the efficiency of a traditional carbon capture device is reduced due to flue gas parameter fluctuation is solved.

Description

Technical Field

[0001] This invention belongs to the field of carbon dioxide emission reduction technology, specifically relating to an adaptive variable load condition cyclic-zonal absorption CO2 capture enhancement device and flexible control method. Background Technology

[0002] With the escalation of global climate change, reducing CO2 emissions has become a top priority in addressing the greenhouse effect and environmental pollution. Carbon capture and storage (CCS) technology for fossil fuel use is gradually becoming an important technological approach to reduce industrial emissions, especially CO2 emissions from the power and chemical industries. Absorption-based CO2 capture technology, with its high absorption efficiency and mature industrial application experience, has become one of the most promising technologies, demonstrating enormous potential, particularly in large-scale industrial applications.

[0003] Existing carbon capture devices typically use the flue gas flow rate of generator sets operating at full load as the basic design parameter. However, due to significant variations in the operating load of generator sets at different times and frequent fluctuations in operating conditions, fluctuating flue gas volume and CO2 concentration lead to substantial changes. This results in reduced carbon capture efficiency, increased energy and material consumption, and even unplanned equipment shutdowns. Therefore, there is an urgent need to develop a highly adaptable, stable, low-cost, and highly efficient carbon capture system to meet the green and high-quality development needs of various industries. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide an adaptive variable load condition cyclic-zonal CO2 capture enhancement device and a flexible control method.

[0005] The specific technical solution is as follows:

[0006] An adaptive variable load condition circulating-zone absorption CO2 capture enhancement device, the main body of the device including, from top to bottom, a demister, a secondary liquid distributor, a secondary packing layer, a secondary adjustable lift cap, a secondary liquid collector, a primary liquid distributor, a primary packing layer, a primary adjustable lift cap, and a primary liquid collector. The secondary liquid collector is connected to a secondary storage tank through a pipeline. One outlet pipeline of the secondary storage tank is connected to the secondary liquid distributor through a secondary circulation pump, and the other outlet pipeline is connected to the primary storage tank. The outlet pipeline of the primary storage tank is connected to the primary liquid distributor through a primary circulation pump. The primary liquid collector is connected to the primary storage tank through a pipeline.

[0007] The device is configured as follows: After cooling, the flue gas is redistributed and mixed through a primary adjustable lift cap and then rises to the primary packing layer, where it contacts the absorbent in the primary packing layer for mass transfer. It then reaches the secondary adjustable lift cap, is redistributed and mixed again, and rises to the secondary packing layer, where it contacts the absorbent in the secondary packing layer for mass transfer. After the absorbent entrained in the gas is recovered by a demister, it is discharged into the atmosphere. The absorbent, from top to bottom, is evenly distributed by a secondary liquid distributor and falls to the secondary packing layer, where it captures carbon dioxide from the flue gas and then falls to the secondary liquid collector. It is then guided through a pipeline to the secondary storage tank. Part of the absorbent is returned to the secondary liquid distributor for further redistribution via a secondary circulation pump, while the other part overflows to the primary storage tank. Together with the absorbent in the primary storage tank, it is guided by a primary circulation pump to the primary liquid distributor, where it is evenly distributed and falls to the primary packing layer to capture carbon dioxide. It then falls to the primary liquid collector. The rich liquid at the bottom of the primary storage tank is guided by a rich liquid pump to the desorption tower for regeneration.

[0008] Furthermore, the demister is a mesh or combined type demister, the primary liquid distributor and the secondary liquid distributor are plug-in type liquid distributors or sawtooth overflow distributors, and the packing used in the primary packing layer and the secondary packing layer is MELLAPAK, FLEXIPAC or PALL, with packing structure parameters of 500Y, 500X, 250X or 250Y.

[0009] Furthermore, the first-stage adjustable lift cap and the second-stage adjustable lift cap, from top to bottom, consist of a welded cap, a closable lift pipe, and a base. The bottom of the closable lift pipe has a controllable sealing cover, which is controlled to open and close by a pneumatic or electric actuator to adjust the flue gas flow rate. The diameter and height of the lift pipe are designed according to the gas-liquid volume when the engine is at full load.

[0010] A flexible control method for an adaptive variable load condition cyclic-zonal CO2 capture enhancement device includes the following steps:

[0011] 1) Based on online and historical operating data, establish a database covering parameters such as fuel type, unit operating conditions, flue gas volume, flue gas velocity, and capture effect;

[0012] 2) Based on the database, combined with knowledge of fuel combustion mechanism and operation experience, analyze the response relationship between unit operating conditions, fuel type and flue gas volume, and establish an accurate prediction model for unit flue gas volume that adapts to variable load conditions;

[0013] 3) Based on the database and the accurate prediction model of flue gas volume, analyze the response relationship between flue gas volume, the percentage of open sealed covers and flue gas velocity, and establish an accurate prediction model of flue gas velocity inside the enhancement device.

[0014] 4) When the operating conditions of the unit fluctuate, the flue gas volume is predicted by the accurate flue gas volume prediction model, the flue gas velocity is predicted by the accurate flue gas velocity prediction model, and the flue gas velocity is adjusted to a stable range by opening and closing the sealing cover at the bottom of part of the riser pipe, thereby optimizing the carbon capture efficiency.

[0015] Furthermore, the accurate prediction model for unit flue gas volume described in step 2) is expressed as follows: , in For the theoretical flue gas volume, m 3 / g; For total air volume, m 3 / g; For the theoretical air volume, m 3 / g; The theoretical flue gas volume calculation formula is: , For the theoretical flue gas volume, m 3 / g; The fuel water content; For fuel nitrogen content; , In the formula, Theoretical air volume , , , These represent the carbon, hydrogen, sulfur, and oxygen content of the fuel, respectively.

[0016] Furthermore, the precise prediction model for the flue gas velocity inside the enhancement device in step 3) is described as follows: , Where V is the flue gas velocity, m / s; n is the number of air lift caps opened, and D is the diameter of the air lift pipe, m.

[0017] The beneficial effects of this invention are as follows:

[0018] 1) To address the problem of large fluctuations in flue gas parameters and reduced flue gas carbon capture efficiency caused by large load changes during unit operation, this invention provides an adaptive variable load condition cyclic-segment absorption CO2 capture enhancement device and flexible control method. By using the cyclic-segment absorption method, the flue gas carbon capture effect is enhanced. Furthermore, by combining the adaptive variable load condition cyclic-segment absorption CO2 capture enhancement flexible control method, stable and efficient CO2 capture is achieved.

[0019] 2) The adjustable gas lift cap provided by the present invention, through a controllable opening and closing closed cover, combined with a unit flue gas volume accurate prediction model adapted to variable load conditions and an internal flue gas velocity accurate prediction model of the enhancement device, achieves accurate control of the internal flue gas velocity of the enhancement device, thus ensuring carbon capture efficiency. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the device of the present invention;

[0021] In the diagram: 1. Demister; 2. Secondary liquid distributor; 3. Secondary packing layer; 4. Secondary adjustable air lift cap; 5. Secondary liquid collector; 6. Secondary liquid storage tank; 7. Secondary circulation pump; 8. Primary liquid distributor; 9. Primary packing layer; 10. Primary adjustable air lift cap; 11. Primary liquid collector; 12. Primary liquid storage tank; 13. Primary circulation pump. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments, but the scope of protection of the present invention is not limited thereto.

[0023] Reference Figure 1 An adaptive variable load condition circulating-zone absorption CO2 capture enhancement device is disclosed. The main body of the device includes, from top to bottom, a demister 1, a secondary liquid distributor 2, a secondary packing layer 3, a secondary adjustable lift cap 4, a secondary liquid collector 5, a primary liquid distributor 8, a primary packing layer 9, a primary adjustable lift cap 10, and a primary liquid collector 11. The secondary liquid collector 5 is connected to a secondary storage tank 6 via a pipeline. One outlet pipeline of the secondary storage tank 6 is connected to the secondary liquid distributor 2 via a secondary circulation pump 7, and the other outlet pipeline is connected to a primary storage tank 12. The outlet pipeline of the primary storage tank 12 is connected to the primary liquid distributor 8 via a primary circulation pump 13. The primary liquid collector 11 is connected to the primary storage tank 12 via a pipeline.

[0024] Demister 1 is a mesh or combined type demister. The primary liquid distributor 8 and the secondary liquid distributor 2 are plug-in type liquid distributors or sawtooth overflow distributors. The primary packing layer 9 and the secondary packing layer 3 use MELLAPAK, FLEXIPAC or PALL packings with packing structure parameters of 500Y, 500X, 250X or 250Y.

[0025] The first-stage adjustable lift cap 10 and the second-stage adjustable lift cap 4 consist of a welded cap, a closable lift pipe, and a base, from top to bottom. The bottom of the closable lift pipe has a controllable sealing cover, which is controlled to open and close by a pneumatic or electric actuator (structure reference CN120403322A) to adjust the flue gas flow rate. The diameter and height of the lift pipe are designed according to the gas-liquid volume when the engine is under full load.

[0026] Example 1

[0027] Using the apparatus described above, for a 600MW coal-fired power unit, the flue gas volume under full power conditions is approximately 2.1 million Nm³. 3 / h, the CO2 concentration in the flue gas is about 12 vol.%. After cooling, the flue gas is redistributed and mixed by the first-stage adjustable lift cap 10 and then rises to the first-stage packing layer 9, where it contacts the absorbent in the first-stage packing layer 9 for mass transfer. After reaching the second-stage adjustable lift cap 4, it is redistributed and mixed and then rises to the second-stage packing layer 3, where it contacts the absorbent in the second-stage packing layer 3 for mass transfer. After passing through the demister 1 to recover the absorbent entrained in the gas, it is discharged into the atmosphere. The absorbent descends from top to bottom, being evenly distributed by the secondary liquid distributor 2 before falling to the secondary packing layer 3. There, it contacts the flue gas and captures CO2, then falls into the secondary liquid collector 5. From there, it is piped to the secondary storage tank 6. Part of the absorbent is guided back to the secondary liquid distributor 2 by the secondary circulation pump 7, while the remaining portion overflows into the primary circulation tank 12. Together with some of the absorbent in the primary circulation tank 12, it is guided by the primary circulation pump 13 to the primary liquid distributor 8. After being evenly distributed by the primary liquid distributor 8, it falls to the primary packing layer 9, where it contacts the flue gas and captures CO2, before falling into the primary liquid collector 11. The rich liquid at the bottom of the primary storage tank 12 is guided by the rich liquid pump to the desorption tower for regeneration.

[0028] In this embodiment, the demister 1 is a combined demister; the liquid distributor is a plug-in liquid distributor; the packing is MELLAPAK, and the packing structure parameter is 250Y.

[0029] In the face of the above-mentioned situation, the carbon capture rate of the circulating-partition absorption CO2 capture enhancement device constructed by the present invention can reach 90%, while the carbon capture rate of conventional carbon capture devices is only 73%.

[0030] Example 2

[0031] The present invention employs a flexible control method for enhanced CO2 capture under adaptive variable load conditions using a cyclic-zonal absorption system. Based on a precise prediction model of the unit's flue gas volume and a calculation model of the flue gas velocity inside the enhancement device, a method for enhanced CO2 capture under adaptive variable load conditions is established, with the CO2 concentration in the flue gas at the capture device outlet serving as a constraint indicator. When the unit's operating conditions fluctuate, the precise prediction model of the unit's flue gas volume enables accurate prediction of the unit's flue gas volume under different operating conditions. Furthermore, by combining this with a precise prediction model of the flue gas velocity inside the enhancement device, the precise prediction of the flue gas velocity inside the capture device under different operating conditions is achieved. Finally, by opening and closing the bottom sealing cover of the partial riser pipe, stable control of the flue gas velocity inside the capture device under different operating conditions is achieved, thereby achieving optimal carbon capture performance.

[0032] The accurate prediction models for unit flue gas volume and internal flue gas velocity of the enhancement device, which are adapted to variable load conditions, include the following steps:

[0033] S1: Based on online and historical operating data, establish a database covering parameters such as fuel type, unit operating conditions, flue gas volume, flue gas velocity, and capture effect;

[0034] S2: Based on the database established in step S1, and combined with the combustion mechanisms and operational experience of different types of fuels, analyze the response relationship between unit operating conditions, fuel type, and flue gas volume. Establish a flue gas volume prediction model for the unit under different operating conditions, and further combine historical operating data of fuel type, unit operating conditions, and flue gas volume to establish an accurate flue gas volume prediction model adapted to variable load conditions;

[0035] S3: Based on the database established in step S1, and combined with the accurate flue gas volume prediction model and operational experience, analyze the response relationship between flue gas volume, the percentage of open sealed covers, and flue gas velocity. Establish flue gas velocity prediction models under different operating conditions, and further combine the percentage of open sealed covers and historical flue gas volume data to establish an accurate flue gas velocity prediction model inside the enhanced device.

[0036] The accurate prediction model for unit flue gas volume described in step 2) is expressed as follows: , in For the theoretical flue gas volume, m 3 / g; For total air volume, m 3 / g; For the theoretical air volume, m 3 / g; The theoretical flue gas volume calculation formula is: , For the theoretical flue gas volume, m 3 / g; The fuel water content; For fuel nitrogen content; , In the formula, Theoretical air volume , , , These represent the carbon, hydrogen, sulfur, and oxygen content of the fuel, respectively.

[0037] The precise prediction model for the flue gas velocity inside the enhancement device in step 3) is expressed as follows: , Where V is the flue gas velocity, m / s; n is the number of air lift caps opened, and D is the diameter of the air lift pipe, m.

[0038] For a 600MW coal-fired power unit, its flue gas volume under full power conditions is approximately 2.1 million Nm³. 3 / h, the CO2 concentration in the flue gas is about 12 vol.%. When its power is reduced from 100% to 75%, the carbon capture rate of conventional carbon capture processes is reduced from 69% to 60%. After using the adaptive variable load condition cycle-zone absorption CO2 capture enhancement flexible control method described in this invention, the carbon capture rate is reduced from 90% to 89%, and the carbon capture effect is efficient and stable.

[0039] Comparative Example

[0040] Using the system described in Example 1 and the flexible control method described in Example 2, for a certain 20000Nm 3 The / h flue gas volume engineering verification platform has a CO2 concentration of approximately 4.6 vol.% in the flue gas. When the flue gas volume changes, the carbon capture rate changes of the conventional process and the process described in this invention are shown in Table 1. As can be seen from Table 1, the carbon capture rate under the new process is basically stable at over 90%, while the conventional carbon capture process decreases by 5% and the carbon capture rate is less than 75%.

[0041] Table 1. Changes in carbon capture rate between conventional processes and flexible control methods

[0042]

[0043] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An adaptive variable load condition cyclic-zonal absorption CO2 capture enhancement device, characterized in that, The main body of the device includes, from top to bottom, a demister (1), a secondary liquid distributor (2), a secondary packing layer (3), a secondary adjustable air-lift cap (4), a secondary liquid collector (5), a primary liquid distributor (8), a primary packing layer (9), a primary adjustable air-lift cap (10), and a primary liquid collector (11). The secondary liquid collector (5) is connected to the secondary storage tank (6) through a pipe. One outlet pipe of the secondary storage tank (6) is connected to the secondary liquid distributor (2) through a secondary circulation pump (7), and the other outlet pipe is connected to the primary storage tank (12). The outlet pipe of the primary storage tank (12) is connected to the primary liquid distributor (8) through a primary circulation pump (13). The primary liquid collector (11) is connected to the primary storage tank (12) through a pipe. The device is configured as follows: after cooling, the flue gas is redistributed and mixed by the first-stage adjustable lift cap (10) and then rises to the first-stage packing layer (9), where it contacts the absorbent in the first-stage packing layer (9) for mass transfer. After reaching the second-stage adjustable lift cap (4), it is redistributed and mixed again and rises to the second-stage packing layer (3), where it contacts the absorbent in the second-stage packing layer (3) for mass transfer. After the absorbent entrained in the gas is recovered by the demister (1), it is discharged into the atmosphere. The absorbent, from top to bottom, is evenly distributed by the second-stage liquid distributor (2) and falls to the second-stage packing layer (3) to capture carbon dioxide in the flue gas. The absorbent then falls to the secondary liquid collector (5), and is guided through the pipeline to the secondary storage tank (6). Part of the absorbent is returned to the secondary liquid distributor (2) via the secondary circulation pump (7) for re-distribution. The other part overflows to the primary storage tank (12), and together with the absorbent in the primary storage tank (12), it is guided by the primary circulation pump (13) to the primary liquid distributor (8). After being distributed, it falls to the primary packing layer (9) to capture carbon dioxide, and falls to the primary liquid collector (11). The bottom rich liquid in the primary storage tank (12) is guided to the desorption tower for regeneration by the rich liquid pump.

2. The adaptive variable load condition cyclic-zonal absorption CO2 capture enhancement device as described in claim 1, characterized in that, The demister (1) is a mesh or combined demister, the primary liquid distributor (8) and the secondary liquid distributor (2) are plug-in liquid distributors or sawtooth overflow distributors, and the packing used in the primary packing layer (9) and the secondary packing layer (3) is MELLAPAK, FLEXIPAC or PALL, and the packing structure parameters are 500Y, 500X, 250X or 250Y.

3. The adaptive variable load condition cyclic-zonal absorption CO2 capture enhancement device as described in claim 1, characterized in that, The first-level adjustable lift cap (10) and the second-level adjustable lift cap (4) consist of a welded cap, a closable lift pipe, and a base from top to bottom. The bottom of the closable lift pipe has a controllable sealing cover. The sealing cover is controlled to open and close by a pneumatic or electric actuator to adjust the flue gas flow rate. The diameter and height of the lift pipe are designed according to the gas-liquid volume when the engine is at full load.

4. A flexible control method for an adaptive variable load condition cyclic-zonal CO2 capture enhancement device as described in claim 1, characterized in that, Includes the following steps: 1) Based on online and historical operating data, establish a database covering parameters such as fuel type, unit operating conditions, flue gas volume, flue gas velocity, and capture effect; 2) Based on the database, combined with knowledge of fuel combustion mechanism and operation experience, analyze the response relationship between unit operating conditions, fuel type and flue gas volume, and establish an accurate prediction model for unit flue gas volume that adapts to variable load conditions; 3) Based on the database and the accurate prediction model of flue gas volume, analyze the response relationship between flue gas volume, the percentage of open sealed covers and flue gas velocity, and establish an accurate prediction model of flue gas velocity inside the enhancement device. 4) When the operating conditions of the unit fluctuate, the flue gas volume is predicted by the accurate flue gas volume prediction model, the flue gas velocity is predicted by the accurate flue gas velocity prediction model, and the flue gas velocity is adjusted to a stable range by opening and closing the sealing cover at the bottom of part of the riser pipe, thereby optimizing the carbon capture efficiency.

5. The flexible control method as described in claim 4, characterized in that, The accurate prediction model for unit flue gas volume described in step 2) is expressed as follows: ， in For the theoretical flue gas volume, m 3 / g; For total air volume, m 3 / g; For the theoretical air volume, m 3 / g; The theoretical flue gas volume calculation formula is: ， For the theoretical flue gas volume, m 3 / g; The fuel water content; This refers to the nitrogen content of the fuel. ， In the formula, Theoretical air volume , , , These represent the carbon, hydrogen, sulfur, and oxygen content of the fuel, respectively.

6. The flexible control method as described in claim 5, characterized in that, The precise prediction model for the flue gas velocity inside the enhancement device in step 3) is expressed as follows: ， Where V is the flue gas velocity, m / s; n is the number of air lift caps opened, and D is the diameter of the air lift pipe, m.

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