Thermal power flue gas carbon capture amine liquid purification system utilizing carbon dioxide purging

Abstract

The invention relates to the technical field of amine liquid purification, and discloses a thermal power flue gas carbon capture amine liquid purification system utilizing carbon dioxide purging, which is connected with a carbon capture system and comprises a resin desalination module respectively connected with a purification pipeline, a gas transmission pipeline, a liquid transmission pipeline and an alkali liquor box; valves are arranged on the purification pipeline, the gas conveying pipeline and the liquid conveying pipeline; the purification pipeline is connected with the filtering subsystem; the filtering subsystem is connected with an amine liquid pipeline; amine liquid of the carbon capture system is input into the filtering subsystem through an amine liquid pipeline; the gas pipeline is connected with a gas outlet of the carbon capture system, and the gas outlet is used for discharging CO2 product gas of the carbon capture system; a compressor is further connected between the air outlet and the air conveying pipeline; the liquid conveying pipeline is respectively connected with the circulating water tank and the desalted water tank. According to the invention, stable alkali liquor cleaning can be realized, and on the basis of ensuring the cleaning cleanliness of the alkali liquor, the amount of wastewater is greatly reduced, the purification period is shortened, the purification efficiency is improved, and the purification cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of amine liquid purification, and in particular to a thermal power flue gas carbon capture amine liquid purification system utilizing carbon dioxide purging. Background Art

[0002] As one of the current mainstream carbon capture technologies, the organic amine liquid used in the chemical absorption method faces degradation problems such as thermal degradation, oxidative degradation and chemical degradation during long-term operation; with the gradual development of flue gas carbon capture projects in thermal power and other industries, these degradation problems have gradually attracted attention. Heat-stable salts (HSS) such as formate, acetate, oxalate, and thiosulfate formed by the degradation of organic amine liquid will have many adverse effects if they are enriched in the carbon capture system for a long time, such as equipment corrosion, amine liquid loss, and reduced CO2 absorption efficiency.

[0003] In order to ensure that the carbon capture system can achieve long-term efficient and stable operation, it is crucial to maintain the quality of the organic amine liquid. At present, the thermal power industry usually draws on the mature experience of the petrochemical industry to implement amine liquid purification treatment to reduce the content of thermally stable salts therein, thereby restoring and improving the absorption capacity of the organic amine liquid and reducing its adverse effects on the carbon capture system. However, compared with the petrochemical industry, the thermal power industry, especially coal-fired power plants, face specific challenges in applying this technology: First, the wastewater treatment capacity is limited; the existing slag water treatment facilities of most coal-fired power plants have a small capacity and it is difficult to cope with the wastewater treatment volume required for large-scale amine liquid purification. Second, the absorption challenge in a low-concentration CO2 environment; the carbon dioxide concentration in coal-fired flue gas is low, making the amine liquid more susceptible to impurity ions (such as Na) during the absorption process. + ) leads to the decline of amine liquid performance. In addition, due to the low CO2 partial pressure, the amine liquid regeneration efficiency is also affected, further increasing the amine liquid consumption. Third, ion interference; during the absorption process, the sodium ions (Na + ) and other impurities will be mixed into the amine solution. The presence of these ions will affect the selectivity and regeneration effect of the amine solution, and ultimately reduce the overall carbon capture efficiency.

[0004] Therefore, in the amine liquid purification process of flue gas carbon capture in the thermal power industry, how to reduce the amount of wastewater while reducing the introduction of sodium ions during the alkali solution flushing during the resin regeneration process is an important issue that affects the long-term stable operation of the thermal power flue gas carbon capture device. At present, in the organic amine liquid purification technology, the ion exchange resin technology uses the principle of resin selective adsorption of anions in the organic amine liquid to remove thermally stable salts. This technology has the advantages of low desalination energy consumption, low organic amine loss and thorough desalination. It is the current mainstream organic amine liquid purification treatment technology. However, this technology has the disadvantages of large wastewater discharge, high alkali consumption, and the alkali solution will inevitably be brought into the carbon capture system. Summary of the invention

[0005] The present invention aims to provide a thermal power flue gas carbon capture amine liquid purification system using carbon dioxide purging, which can achieve stable alkali liquid cleaning and, on the basis of ensuring the cleanliness of the alkali liquid cleaning, greatly reduce the amount of wastewater, shorten the purification cycle, improve the purification efficiency, and reduce the purification cost.

[0006] The basic scheme provided by the present invention is: a thermal power flue gas carbon capture amine liquid purification system using carbon dioxide purge, connected to the carbon capture system, including: a resin desalination module, the resin desalination module is respectively connected to the purification pipeline, the gas pipeline, the liquid pipeline and the alkali liquid tank; the purification pipeline, the gas pipeline and the liquid pipeline are all provided with valves;

[0007] The purification pipeline is connected to the filtering subsystem; the filtering subsystem is connected to the amine liquid pipeline; the amine liquid of the carbon capture system is input into the filtering subsystem through the amine liquid pipeline;

[0008] The gas pipeline is connected to the gas outlet of the carbon capture system, and the gas outlet is used to discharge the CO2 product gas of the carbon capture system; a compressor is also connected between the gas outlet and the gas pipeline;

[0009] The liquid delivery pipeline is connected to the circulating water tank and the desalted water tank respectively.

[0010] The working principle and advantages of the present invention are:

[0011] In specific applications, the working principle of this system is as follows: the amine liquid of the carbon capture system is input into the filtration subsystem through the amine liquid pipeline, filtered by the filtration subsystem, and then enters the resin desalination module, where it is desalted and can be transported back to the carbon capture system through the amine liquid pipeline after desalination. The circulating water tank is activated again, and the water in the circulating water tank is pumped into the resin desalination module through the infusion pipeline, thereby completing the first flushing of the resin desalination module. The flushed water can be sent to the carbon capture system through the amine liquid pipeline, thereby achieving the purpose of recovering the amine liquid. The desalted water tank is activated again, and the desalted water in the desalted water tank is pumped into the resin desalination module through the infusion pipeline, thereby completing the second flushing of the resin desalination module. The desalted water after flushing can be returned to the circulating water tank through the infusion pipeline as the flushing water for the next cycle. The alkali liquid tank is activated again, and alkali liquid is input into the resin desalination module to regenerate the resin. After the regeneration is completed, the alkali liquid is discharged. The desalted water tank is activated again, and the resin desalination module is flushed for the third time to clean the alkali liquid for the first time, and the desalted water after flushing is discharged.

[0012] Then open the valve on the gas pipeline, and the CO2 product gas of the carbon capture system enters the gas pipeline from the gas outlet, and enters the resin desalination module after being processed by the compressor, where it is purged to achieve secondary cleaning of the alkaline solution in the resin desalination module. The cleaned CO2 product gas can be recycled.

[0013] The present invention discloses a thermal power flue gas carbon capture amine liquid purification system using carbon dioxide purge, which can achieve stable alkali liquid cleaning, and on the basis of ensuring the cleanliness of the alkali liquid cleaning, greatly reduce the amount of wastewater, shorten the purification cycle, improve the purification efficiency, and reduce the purification cost. The key point is: this solution uses the CO2 product gas of the carbon capture system in a breakthrough way, and cleans the resin desalination module (especially the alkali liquid cleaning) by purge, which can reduce the amount of wastewater and ensure the cleaning quality and efficiency.

[0014] Specifically, this scheme first excavates the reasons why the existing organic amine liquid purification technology (ion exchange resin technology) has the disadvantages of large wastewater discharge, high alkali consumption, and alkali liquid will inevitably be brought into the carbon capture system, and overcomes the difficulties, providing an effective path for the optimization of ion exchange resin technology. In ion exchange resin technology, after the resin is purified, deionized water is usually used to rinse the resin to prevent the regenerated alkali liquid from entering the system, and the deionized water is used as wastewater for external treatment after rinsing. The main function of this step is to reduce the amount of alkali liquid residual in the resin tank, but if the number of rinses is too large and the amount of rinses is too large, the amount of wastewater will increase; too few rinses and too low a rinse amount will cause alkali liquid to remain in the resin tank, which will be brought into the system by amine liquid in the next cycle. Based on this situation, this scheme did not choose to calculate and control the water volume or number of times according to the usual thinking, but designed a new purge technology, using the CO2 product gas of the carbon capture system instead of deionized water for alkali flushing / purging.

[0015] The key points of this technology are: first, CO2 product gas can be used to replace desalted water, which greatly reduces the amount of desalted water and the amount of wastewater generated from the source, can effectively reduce the wastewater treatment pressure of power plants, and is suitable for the actual conditions of most coal-fired power plants, with high application value; second, the use of CO2 product gas purging can be combined with the carbon capture system of the power plant to achieve a high degree of recycling of the regenerated gas of the carbon capture system, which has high environmental benefits. In addition, compared with compressed air purging, the CO2 product gas of the carbon capture system is a high-purity CO2 gas, which can provide greater pressure and improve the purging efficiency. In addition, the water content of compressed air in general power plants is relatively high, and there is also the risk of instrument and valve failure when water is brought in, while high-purity CO2 gas can be almost free of water, which greatly improves the stability of the system. This solution can not only ensure that the resin is thoroughly cleaned and avoid alkali liquid from being brought into the system, but also achieve the purpose of reducing the amount of regenerated wastewater and reducing the pressure of back-end wastewater treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The present invention is a schematic diagram of the system structure of an embodiment of a thermal power flue gas carbon capture amine liquid purification system using carbon dioxide purge. DETAILED DESCRIPTION

[0017] The following is a further detailed description through specific implementation methods:

[0018] The symbols in the drawings of the specification include: a first resin desalination module 1, a second resin desalination module 2, a filtering subsystem 3, a circulating water tank 4, a desalted water tank 5, an alkali liquid tank 6, a liquid infusion pipeline 7, a gas-liquid separator 8, a waste liquid discharge pipe 9, a pressure reducing valve 10, a purification pipeline 11, a gas pipeline 12, an amine liquid pipeline 13, and a valve 14.

[0019] The embodiment is basically as shown in the attached Figure 1 As shown: a thermal power flue gas carbon capture amine liquid purification system using carbon dioxide purging, connected to the carbon capture system, including: a resin desalination module, the resin desalination module is respectively connected to the purification pipeline 11, the gas pipeline 12, the liquid pipeline 7 and the alkali liquid tank 6; the purification pipeline 11, the gas pipeline 12 and the liquid pipeline 7 are all provided with valves 14 (in this embodiment, specifically electric valves).

[0020] In this embodiment, the resin desalination module is specifically an ion exchange resin desalination module, and there are two of them, including a first resin desalination module 1 and a second resin desalination module 2; and the two resin desalination modules are respectively connected to the purification pipeline 11, the gas pipeline 12, the liquid pipeline 7 and the alkali liquid tank 6. In the purge stage, the two resin desalination modules operate alternately. Valves 14 are respectively provided at the front and rear ends of the two resin desalination modules to facilitate the control of liquid or gas entering and exiting a resin desalination module separately.

[0021] The resin desalination module is connected to the alkali liquid tank 6 through an alkali liquid pipeline. The alkali liquid in the alkali liquid tank 6 is pumped into the resin desalination module through the alkali liquid pipeline, enters the resin bed in the resin desalination module from top to bottom for resin regeneration, and is discharged through the liquid infusion pipeline 7 after regeneration is completed.

[0022] The purification pipeline is connected to the filtering subsystem 3; the filtering subsystem 3 is connected to the amine liquid pipeline 13; the amine liquid of the carbon capture system is input into the filtering subsystem 3 through the amine liquid pipeline 13. The amine liquid pipeline 13 is arranged between the lean liquid water cooler and the absorption tower of the carbon capture system. A valve 14 is arranged at the front and rear ends of the filtering subsystem 3 to facilitate more accurate liquid flow control and to facilitate the maintenance and replacement of the filtering subsystem 3.

[0023] The filtering subsystem 3 includes a first security filter and a second security filter connected in series; the rated filtering accuracy of the first security filter is 1-5 μm; the rated filtering accuracy of the second security filter is 0.5-1 μm. Here, the stepped interception accuracy configuration of the two-stage filter is used to ensure efficient interception of suspended matter of different particle sizes, improve the removal rate of suspended matter, and avoid clogging of the filter element.

[0024] The gas pipeline 12 is connected to the gas outlet of the carbon capture system, and the gas outlet is used to discharge the CO2 product gas of the carbon capture system; and when the gas pipeline 12 is connected to the resin desalination module, its connection end is divided into two sub-pipelines, which are respectively connected to the first resin desalination module 1 and the second resin desalination module 2, and a valve is provided on each pipeline to facilitate accurate control of the passage, discharge and cutoff of the gas flow. A compressor, a dryer and a pressure reducing valve 10 are also connected between the gas outlet and the gas pipeline 12; the dryer is arranged after the compressor, and the pressure reducing valve 10 is arranged after the dryer, that is, the compressor, the dryer and the pressure reducing valve 10 are arranged in sequence. The CO2 product gas is a high-purity CO2 gas; after the CO2 product gas enters the resin desalination module through the gas pipeline 12, the resin bed in the resin desalination module is purged from bottom to top; the single purge time is set to 600s, and the purge flow rate is set to 5m 3 / h.

[0025] The resin desalination module is also connected to the gas-liquid separator 8; the CO2 product gas enters the gas-liquid separator 8 after the purge is completed; the exhaust port of the gas-liquid separator 8 is connected to the carbon capture system; the discharge port of the gas-liquid separator 8 is connected to the waste liquid discharge pipe 9.

[0026] The liquid infusion pipeline 7 is respectively connected to the circulating water tank 4 and the desalted water tank 5. Specifically, one end of the liquid infusion pipeline 7 is divided into two sub-pipelines, which are respectively connected to the circulating water tank 4 and the desalted water tank 5, and a valve is provided on each pipeline. After the water in the circulating water tank 4 is pumped into the resin desalination module through the liquid infusion pipeline 7, the resin bed in the resin desalination module is flushed from bottom to top, and after the flushing is completed, the resin bed enters the carbon capture system through the amine liquid pipeline 13; after the desalted water in the desalted water tank 5 is pumped into the resin desalination module through the liquid infusion pipeline 7, the resin bed in the resin desalination module is flushed from bottom to top, and after the flushing is completed, the resin bed enters the carbon capture system through the amine liquid pipeline 13.

[0027] In specific applications, the operation process of this purification system is as follows: there are two resin desalination modules, the resin filling volume of each desalination module is 160-200L, and the single-cycle inlet flow rate of the amine solution is set to 8-12m 3 / h, the pressure (specifically the pressure of the amine liquid entering the resin tank) is set to 0.4-0.6MPa:

[0028] Stage 1: Add amine solution.

[0029] The amine liquid enters the purification system from the amine liquid pipeline 13 between the lean liquid water cooler and the absorption tower of the carbon capture system. Since the lean liquid is under pressure here, no additional pump is set. After the amine liquid enters the purification system, it first passes through the filtering subsystem 3, and is filtered in turn by the first security filter and the second security filter, and then enters the first resin desalination module 1 from bottom to top. At this time, in the two resin desalination modules, when the module valve 14 on one side is opened and the amine liquid is flowing, the module valve 14 on the other side is closed. In this embodiment, it is tentatively determined that the valve 14 at the first resin desalination module 1 is opened, and the valve 14 at the second resin desalination module 2 is closed. After completing desalination in the first resin desalination module 1, the amine liquid returns to the amine liquid pipeline 13 and is pumped into the carbon capture system again.

[0030] In this stage, the purification time is set to 300s.

[0031] Stage 2, circulating water flushing.

[0032] The water in the circulating water tank 4 is pumped into the first resin desalination module 1 through the liquid delivery pipe 7 to flush the resin bed in the resin desalination module from bottom to top, and after the flushing is completed, it enters the carbon capture system through the amine liquid pipe 13 to achieve the purpose of recovering the amine liquid.

[0033] In this stage, the circulating water volume is set to 60L and the duration is 120s.

[0034] Stage 3, demineralized water rinse.

[0035] The desalted water in the desalted water tank 5 is pumped into the first resin desalination module 1 through the liquid delivery pipe 7 to flush the resin bed in the first resin desalination module 1 from bottom to top, and after the flushing is completed, it enters the carbon capture system through the amine liquid pipe 13 to achieve the purpose of recovering the amine liquid.

[0036] In this stage, the flushing water volume is set to 60L and the duration is 120s.

[0037] Stage 4: deionized water flushing and recovery.

[0038] The deionized water in the deionized water tank 5 is pumped into the first resin deionization module 1 again to flush the resin bed in the first resin deionization module 1 from bottom to top, and after flushing, it returns to the circulating water tank 4 through the liquid infusion pipe 7 as flushing water for the next cycle.

[0039] In this stage, the flushing water volume is set to 60L and the duration is 120s.

[0040] Stage 5, resin regeneration.

[0041] The alkali liquid in the alkali liquid tank 6 is pumped into the first resin desalination module 1 , and enters the resin bed in the first resin desalination module 1 from top to bottom for resin regeneration, and is discharged through the liquid delivery pipeline 7 after the regeneration is completed.

[0042] In this stage, the alkali consumption is set to 80L and the duration is 200s.

[0043] Stage 6, lye rinse.

[0044] The desalted water in the desalted water tank 5 is pumped into the first resin desalination module 1 through the liquid delivery pipe 7 to flush the resin bed in the first resin desalination module 1 from bottom to top to take away the residual alkali solution. After the flushing is completed, it is discharged through the waste liquid discharge pipe 9 for external treatment.

[0045] In this stage, the flushing water volume is set to 60L and the duration is 120s. Here, compared with the demineralized water flushing method used in the traditional purification scheme, in order to ensure that the alkali solution flushing is as clean as possible, the traditional scheme generally requires 180L of demineralized water, divided into 2 or 3 flushings, and the duration is 360s. This scheme greatly reduces the water consumption and duration of this stage, and uses stage 7 to ensure the cleanliness of the flushing.

[0046] Stage 7, next round of purification and lye rinse.

[0047] The electric valves of the liquid pipelines before and after the first resin desalination module 1 are closed, and the electric valves of the liquid pipelines before and after the second resin desalination module 2 are opened to start the next round of amine liquid purification.

[0048] At this time, the amine liquid enters the second resin desalination module 2 for purification, and the first resin desalination module 1 is separated. When the second resin desalination module 2 is normally purified, the CO2 product gas of the carbon capture system is compressed by the compressor and dried by the dryer (the purity of CO2 is above 99.9%) and introduced into the amine liquid purification system, and the CO2 gas pressure is reduced from 2.2MPa to 0.6-1.0Mpa through the pressure reducing valve 10, and then the resin bed of the first resin desalination module 1 is purged from bottom to top, and enters the gas-liquid separator after the purging is completed; the gaseous CO2 enters the carbon capture system from the pipeline between the lean liquid water cooler and the absorption tower, and is absorbed again (optionally, the gaseous CO2 is directly returned to the compressor for compression), so as to realize the recycling of CO2; the purged alkali liquid enters the waste liquid discharge pipe 9 after the gas-liquid separator and is discharged as waste liquid.

[0049] In this stage, the purge duration is set to 600s and the purge flow rate is set to 5m 3 / h.

[0050] Stage 8, resin module switching.

[0051] In the new round of amine liquid purification, the resin bed of the first resin desalination module 1 can be continuously purged, which prolongs the purging time and further reduces the residual alkali solution. After the second resin desalination module 2 completes the system purification, it is also separated out for purging, and the system switches to the first resin desalination module 1 for the next round of purification.

[0052] To further demonstrate the superiority and effectiveness of the present scheme, in this embodiment, under the same conditions, the present scheme and the traditional scheme were used to conduct purification experiments on the amine liquid of the same carbon capture device of a power plant; the experimental results are shown in Tables 1 and 2.

[0053] Here, the conventional solution refers to the existing solution of flushing the resin tank with deionized water after the resin is regenerated in stage 5, and discharging the deionized water as wastewater.

[0054] (1) In this scheme, the time required for a single purification cycle is reduced from 1220s (traditional scheme) to 980s, and 17 purification cycles can be added in 24 hours a day, thereby improving the purification effect and shortening the purification cycle. In addition, the comparison of the thermally stable salt content of the carbon capture system during the implementation of this scheme and the traditional scheme is shown in Table 1. It can be found that the thermally stable salt content of the system purified by this scheme decreases faster, and the purification effect is significantly improved.

[0055] Table 1 Comparison of heat stable salt content

[0056]

[0057] (2) In this scheme, the wastewater volume in a single cycle is reduced from 260L (traditional scheme) to 140L. Furthermore, the wastewater volume in 24 hours a day can be reduced from 18.4t to 12.3t, a reduction of 6.1t per day. The comparison of the system wastewater volume during the implementation of this scheme and the traditional scheme is shown in Table 2. It can be found that within a large purification cycle (30 days), the wastewater volume can be reduced by 180t, greatly reducing the wastewater treatment pressure of the power plant.

[0058] Table 2 Wastewater volume comparison table

[0059]

[0060] The present embodiment provides a thermal power flue gas carbon capture amine liquid purification system using carbon dioxide purge, which can achieve stable alkali liquid cleaning, and on the basis of ensuring the cleanliness of the alkali liquid cleaning, greatly reduce the amount of wastewater, shorten the purification cycle, improve the purification efficiency, and reduce the purification cost. The key point is that, first, this solution uses the CO2 product gas of the carbon capture system in a breakthrough way, and cleans the resin desalination module by purge, which can reduce the amount of wastewater and ensure the cleaning quality and efficiency. Specifically, this solution uses CO2 product gas to replace desalted water, which can greatly reduce the amount of desalted water and the amount of wastewater generated, and reduce the wastewater treatment pressure of the power plant; and it can be combined with the carbon capture system of the power plant. Compared with compressed air purge, the CO2 product gas of the carbon capture system is a high-purity CO2 gas, which can provide greater pressure and improve the purge efficiency. In addition, the water content of compressed air in general power plants is relatively high, and there is also a risk of instrument and valve failure when water is brought in, while high-purity gas can be almost free of water, which greatly improves the stability of the system. This technology can not only ensure that the resin is cleaned thoroughly and avoid alkali solution from entering the system, but also reduce the amount of regeneration wastewater and reduce the pressure of back-end wastewater treatment.

[0061] Second, this solution sets up two resin desalination modules, which can be switched for use. When purging the alkali solution, it will not affect the use of the purification system. Compared with setting up only one resin desalination module, it can extend the purging time to ensure that the alkali solution is purged cleanly; second, it can reduce the duration of each purification cycle and improve the purification efficiency.

[0062] The above is only an embodiment of the present invention. The common sense such as the known specific structure and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field are aware of all the common technical knowledge in the technical field of the invention before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement the scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for the ordinary technicians in the relevant field to implement this application. It should be pointed out that for the technicians in this field, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. A carbon capture amine liquid purification system for thermal power flue gas using carbon dioxide purge, connected to a carbon capture system, characterized in that: include: A resin desalination module, wherein the resin desalination module is respectively connected to a purification pipeline, a gas pipeline, a liquid infusion pipeline and an alkali liquid tank; valves are provided on the purification pipeline, the gas pipeline and the liquid infusion pipeline; The purification pipeline is connected to the filtering subsystem; the filtering subsystem is connected to the amine liquid pipeline; the amine liquid of the carbon capture system is input into the filtering subsystem through the amine liquid pipeline; The gas pipeline is connected to the gas outlet of the carbon capture system, and the gas outlet is used to discharge the CO2 product gas of the carbon capture system; a compressor is also connected between the gas outlet and the gas pipeline; The liquid delivery pipeline is connected to the circulating water tank and the desalted water tank respectively.

2. The carbon capture amine liquid purification system for thermal power flue gas using carbon dioxide purge according to claim 1 is characterized in that: A dryer is also connected between the air outlet and the air pipeline; the dryer is arranged after the compressor.

3. The carbon capture amine liquid purification system for thermal power flue gas using carbon dioxide purge according to claim 2 is characterized in that: A pressure reducing valve is also connected between the gas outlet and the gas pipeline; the pressure reducing valve is arranged after the dryer.

4. The carbon capture amine liquid purification system for thermal power flue gas using carbon dioxide purge according to claim 1 is characterized in that: The filtering subsystem includes a first security filter and a second security filter; the rated filtering accuracy of the first security filter is 1-5 μm; the rated filtering accuracy of the second security filter is 0.5-1 μm.

5. The carbon capture amine liquid purification system for thermal power flue gas using carbon dioxide purge according to claim 1 is characterized in that: The resin desalination modules are provided with two, including a first resin desalination module and a second resin desalination module; and the two resin desalination modules are respectively connected to the purification pipeline, the gas pipeline, the liquid pipeline and the alkali liquid tank.

6. A thermal power flue gas carbon capture amine liquid purification system using carbon dioxide purge according to claim 5, characterized in that: During the purge phase, the two resin desalination modules operate alternately.

7. The carbon capture amine liquid purification system for thermal power flue gas using carbon dioxide purge according to claim 1 is characterized in that: The water in the circulating water tank is pumped into the resin desalination module through the liquid delivery pipeline, and then the resin bed in the resin desalination module is flushed from bottom to top, and after the flushing is completed, the water enters the carbon capture system through the amine liquid pipeline; The desalted water in the desalted water tank is pumped into the resin desalination module through the liquid delivery pipeline, and then the resin bed in the resin desalination module is flushed from bottom to top. After the flushing is completed, the desalted water enters the carbon capture system through the amine liquid pipeline or is discharged through the waste liquid discharge pipe for external treatment.

8. The carbon capture amine liquid purification system for thermal power flue gas using carbon dioxide purge according to claim 1 is characterized in that: After the CO2 product gas enters the resin desalination module through the gas pipeline, the resin bed in the resin desalination module is purged from bottom to top.

9. A thermal power flue gas carbon capture amine liquid purification system using carbon dioxide purge according to claim 8, characterized in that: The resin desalination module is also connected to a gas-liquid separator; the CO n The product gas enters the gas-liquid separator after the purging is completed; the exhaust port of the gas-liquid separator is connected to the carbon capture system; the liquid discharge port of the gas-liquid separator is connected to the waste liquid discharge pipe.

10. The thermal power flue gas carbon capture amine liquid purification system using carbon dioxide purge according to claim 8, characterized in that: The single purge duration is set to 600s and the purge flow rate is set to 5m 3 / h.

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