A waste liquid treatment system for solution purification and recovery

Abstract

The present invention proposes a waste liquid treatment system for solution purification and recovery, comprising: a washing unit, an absorption and regeneration unit and a purification unit. The washing unit comprises a washing tower and a spray component, the spray component is connected to the washing tower, the absorption and regeneration unit comprises an absorption tower, a regeneration tower and a heat exchanger, a heat exchanger is provided between the absorption tower and the regeneration tower, and an absorbent can circulate between the absorption tower and the regeneration tower. The purification unit comprises a filtering component, an electrodialysis component and a resin purification component connected in sequence, the absorbent is purified in sequence by the filtering component, the electrodialysis component and the resin purification component, the resin purification component comprises a resin tank and a flushing component, the flushing component is used to pass regeneration liquid into the resin tank to flush the resin tank and generate alkaline solution, and the alkaline solution is used to pass into the spraying component. The waste liquid treatment system for solution purification and recovery of the present invention has the advantages of good treatment effect and high waste liquid utilization rate.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon capture, and in particular to a waste liquid treatment system for solution purification and recovery. Background Art

[0002] The flue gas generated by the combustion of coal-fired power plants is denitrified, dusted and desulfurized, and then pressurized by a blower before entering a composite absorption tower to absorb carbon dioxide. After the capture solution in the absorption tower reacts with the carbon dioxide in the flue gas, its exchange capacity will gradually decrease. Therefore, the capture solution after the reaction needs to be purified and recovered. The treatment methods for the capture solution include chemical absorption, solution washing, membrane separation and adsorption, among which chemical absorption is currently the most widely used and most mature technology.

[0003] In the related art, the organic amine solution in the chemical absorption method is a commonly used absorbent in the carbon dioxide capture process. After the absorbent contacts and reacts with the flue gas in the absorption tower, the corresponding carbamate or carbonate is generated, and the absorbent after the reaction needs to be purified, regenerated and other steps to release the carbon dioxide in the absorbent and recover the absorbent for recycling. Among them, when the absorbent after the reaction is treated, a large amount of waste liquid, such as alkaline waste liquid, is generated, so it is necessary to use one or more methods such as neutralization, evaporation, ion exchange, crystallization and chemical precipitation to treat the generated waste liquid. As a result, the waste liquid treatment equipment is too complicated, and the consumption of chemical solutions is increased, thereby increasing the cost of the overall system. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art to at least some extent. To this end, an embodiment of the present invention provides a waste liquid treatment system for solution purification and recovery, which has good treatment effect and high waste liquid utilization rate.

[0005] The waste liquid treatment system for solution purification and recovery according to the embodiment of the present invention comprises:

[0006] A washing unit, the washing unit comprising a washing tower and a spray assembly, the washing tower having a flue gas inlet and a flue gas outlet, the flue gas inlet being used to introduce flue gas after desulfurization and denitration, the spray assembly being connected to the washing tower so that a spray liquid circulates between the spray assembly and the washing tower, and removes impurities and cools the flue gas in the washing tower;

[0007] An absorption regeneration unit, the absorption regeneration unit comprising an absorption tower, a regeneration tower and a heat exchanger, the absorption tower having an absorption inlet and an absorption outlet, the regeneration tower having a regeneration inlet and a regeneration outlet, the absorption outlet, the cold side of the heat exchanger and the regeneration inlet are connected by a pipeline, the regeneration outlet, the hot side of the heat exchanger and the absorption inlet are connected by a pipeline, so that the absorbent can circulate between the absorption tower and the regeneration tower;

[0008] A purification unit, the purification unit comprising a filter assembly, an electrodialysis assembly and a resin purification assembly connected in sequence, the filter assembly having a filter inlet, a purification outlet and a purification inlet on a pipeline between the absorption inlet and the hot side of the heat exchanger, the purification outlet being located upstream of the purification inlet, the filter inlet being communicated with the purification outlet,

[0009] The resin purification component includes a resin tank and a flushing component, wherein the flushing component is connected to the resin tank and is used to introduce regeneration liquid into the resin tank to flush the resin tank and generate alkaline solution. The resin tank has an alkaline solution outlet and a clean liquid outlet, wherein the clean liquid outlet is connected to the purification inlet, and the alkaline solution outlet is connected to the spray component.

[0010] The waste liquid treatment system for solution purification and recovery of the embodiment of the present invention utilizes a purification unit to purify the absorbent discharged from the absorption tower through a filtration component, an electrodialysis component, and a resin purification component in sequence, and the alkali solution generated during the purification process is passed into the washing tower so as to be mixed with the spray liquid of the washing tower to neutralize the spray liquid used in the washing tower, thereby improving the impurity removal effect of the washing tower. In addition, in the heat exchange, the absorbent discharged from the absorption tower is exchanged with the absorbent discharged from the regeneration tower, which can ensure that the absorbent reduces the temperature of the absorbent discharged from the regeneration tower, so that the temperature of the absorbent passing into the purification unit reaches a suitable temperature to improve the purification effect.

[0011] In some embodiments, the waste liquid treatment system for solution purification and recovery of the embodiments of the present invention also includes a concentration component, the washing tower has a spray inlet and a spray outlet, the spray component is connected to both the spray inlet and the spray outlet, the cold side inlet of the concentration component is connected to the spray outlet, and the hot side inlet of the concentration component is connected to the regeneration gas outlet of the regeneration tower, so that the regeneration gas discharged from the regeneration gas outlet of the regeneration tower passes into the concentration component and heats and concentrates the spray liquid.

[0012] In some embodiments, the alkali solution outlet is connected to a pipeline between the spray outlet and a cold side inlet of the concentration component through a pipeline.

[0013] In some embodiments, the purification unit further comprises a solution pump, which is disposed on a pipeline between the purification outlet and the filtration inlet, and is used to extract 10% to 15% of the absorbent in the absorption tower.

[0014] In some embodiments, the filtration assembly includes a filter and a plurality of buffer tanks, wherein the plurality of buffer tanks are arranged in parallel and connected between the filter and the electrodialysis assembly.

[0015] In some embodiments, the electrodialysis component includes an electrodialysis reactor and a drainage pipeline, the fresh water chamber of the electrodialysis reactor is connected to the cache tank, one end of the drainage pipeline is connected to the fresh water chamber of the electrodialysis reactor, and the other end of the drainage pipeline is connected to the cache tank, so that the liquid in the fresh water chamber of the electrodialysis reactor can flow into the cache tank through the drainage pipeline.

[0016] The electrodialysis component also includes a pole liquid circulation component and a waste liquid circulation component, the pole liquid circulation component includes a pole liquid tank and a first pump, the pole liquid tank, the first pump and the fresh water chamber of the electrodialysis reactor are connected by a pipeline, the pole liquid tank has a first water injection port, the first water injection port is used to inject water into the pole liquid tank, the pole liquid circulation component is connected to the fresh water chamber of the electrodialysis reactor, so as to circulate the absorbent in the fresh water chamber of the electrodialysis reactor between the fresh water chamber of the electrodialysis reactor and the pole liquid circulation component;

[0017] The waste liquid circulation component includes a waste liquid tank and a second pump, the waste liquid tank, the second pump and the concentrated water chamber of the electrodialysis reactor are connected by a pipeline, the waste liquid tank has a second water injection port, the second water injection port is used to inject water into the waste liquid tank, the waste liquid circulation component is connected to the concentrated water chamber of the electrodialysis reactor, so as to circulate the absorbent in the concentrated water chamber of the electrodialysis reactor between the concentrated water chamber of the electrodialysis reactor and the waste liquid circulation component. In some embodiments, the resin purification component also includes an alkali storage tank and a regeneration pipeline, the flushing component is connected to the alkali storage tank for passing regeneration liquid into the alkali storage tank, one end of the regeneration pipeline is connected to the alkali storage tank, and the other end of the regeneration pipeline is connected to the resin tank.

[0018] In some embodiments, the resin purification component further includes an alkali circulation pipeline, which is connected to the alkali storage tank so that part of the alkali solution in the alkali storage tank can circulate between the alkali circulation pipeline and the alkali storage tank.

[0019] In some embodiments, the resin purification assembly further includes a pressurizing member connected to the resin tank for introducing pressurized gas into the resin tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure of a waste liquid treatment system for solution purification and recovery according to an embodiment of the present invention.

[0021] Figure 2 It is a schematic structural diagram of a purification unit of a waste liquid treatment system for solution purification and recovery according to an embodiment of the present invention.

[0022] Reference numerals:

[0023] 100. Coal-fired power plant boiler, 200. Desulfurization and denitrification unit, 300. Coal powder solidification unit,

[0024] 1. Washing unit, 11. Washing tower, 111. Smoke inlet, 112. Smoke outlet, 113. Spray inlet, 114. Spray outlet, 12. Spray assembly,

[0025] 2. Absorption and regeneration unit, 21. Absorption tower, 22. Regeneration tower, 23. Heat exchanger, 24. Purification outlet, 25. Purification inlet,

[0026] 3. Purification unit,

[0027] 31. Filter assembly, 311. Activated carbon filter, 3111. Filter inlet, 312. Microporous filter, 313. Cache tank,

[0028] 32. Electrodialysis assembly, 321. Electrodialysis reactor, 322. Drainage pipeline, 323. Electrode liquid circulation assembly, 3231. Electrode liquid tank, 3232. First water injection port, 3233. First pump, 324. Waste liquid circulation assembly, 3241. Waste liquid tank, 3242. Second water injection port, 3243. Second pump,

[0029] 33. Resin purification assembly, 331. Resin tank, 332. Flushing assembly, 3321. Flushing outlet, 333. Alkali storage tank, 334. Regeneration pipeline, 335. Alkali circulation pipeline, 336. Pressurized parts,

[0030] 34. Alkali solution outlet,

[0031] 35. Clean liquid outlet,

[0032] 36. Solution pump,

[0033] 4. Concentration component. DETAILED DESCRIPTION

[0034] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0035] like Figure 1and Figure 2 As shown, the waste liquid treatment system for solution purification and recovery according to the embodiment of the present invention comprises: a washing unit 1 , an absorption and regeneration unit 2 and a purification unit 3 .

[0036] The washing unit 1 includes a washing tower 11 and a spray assembly 12. The washing tower 11 has a flue gas inlet 111 and a flue gas outlet 112. The flue gas inlet 111 is used to introduce flue gas after desulfurization and denitrification. The spray assembly 12 is connected to the washing tower 11 so that the spray liquid circulates between the spray assembly 12 and the washing tower 11, and removes impurities and cools the flue gas in the washing tower 11.

[0037] Specifically, Figure 1 As shown, the spray assembly 12 includes a spray pipeline and a spray pump arranged on the spray pipeline. When the spray pump is started, the spray liquid can be sprayed from the top of the washing tower 11 into the washing tower 11, so that the spray liquid can contact the flue gas introduced into the washing tower 11, thereby utilizing the spray liquid to remove harmful gases such as sulfur dioxide and nitrogen oxides in the flue gas, and can also cool the flue gas.

[0038] It is understandable that if Figure 1 As shown, the flue gas source may be a coal-fired power plant boiler 100. Before entering the scrubbing tower 11, the flue gas may be subjected to desulfurization, denitrification, dust removal and other treatments using a desulfurization and denitrification unit 200. The treated flue gas is passed into the scrubbing tower 11 for spraying and cooling, wherein the spraying liquid may be water in order to remove harmful gases such as sulfur dioxide and nitrogen oxides carried in the flue gas.

[0039] The absorption and regeneration unit 2 includes an absorption tower 21, a regeneration tower 22 and a heat exchanger 23. The absorption tower 21 has an absorption inlet and an absorption outlet, and the regeneration tower 22 has a regeneration inlet and a regeneration outlet. The absorption outlet, the cold side of the heat exchanger 23 and the regeneration inlet are connected by a pipeline, and the regeneration outlet, the hot side of the heat exchanger 23 and the absorption inlet are connected by a pipeline so that the absorbent can circulate between the absorption tower 21 and the regeneration tower 22.

[0040] like Figure 1 As shown, the absorbent introduced into the absorption tower 21 contacts the flue gas in the absorption tower 21 to capture the carbon dioxide in the flue gas. The absorbent after reacting with the flue gas enters the regeneration tower 22 through the absorption outlet, the heat exchanger 23 and the regeneration inlet for regeneration. The regenerated absorbent is introduced into the absorption tower 21 again through the regeneration outlet, the heat exchanger 23 and the absorption inlet to react with the flue gas again. Thus, the absorbent discharged from the regeneration outlet exchanges heat with the absorbent discharged from the absorption outlet in the heat exchanger 23, so that the absorbent discharged from the absorption outlet is heated, while the absorbent discharged from the regeneration outlet is cooled, so as to facilitate the subsequent purification of the absorbent and to continue to react with the flue gas in the absorption tower 21. Among them, the flow of the absorbent can be driven by a pump.

[0041] The purification unit 3 includes a filter component 31, an electrodialysis component 32 and a resin purification component 33 connected in sequence. The filter component 31 has a filter inlet 3111. The pipeline between the absorption inlet and the hot side of the heat exchanger 23 is provided with a purification outlet 24 and a purification inlet 25. The purification outlet 24 is located upstream of the purification inlet 25. The filter inlet 3111 is connected to the purification outlet 24. The resin purification component 33 includes a resin tank 331 and a flushing component 332. The flushing component 332 is connected to the resin tank 331. The flushing component 332 is used to pass regeneration liquid into the resin tank 331 to flush the resin tank 331 and generate alkaline solution. The resin tank 331 has an alkaline solution outlet 34 and a clean liquid outlet 35. The clean liquid outlet 35 is connected to the purification inlet 25, and the alkaline solution outlet 34 is connected to the spray component 12.

[0042] like Figure 1 As shown, part of the absorbent is passed through the purification outlet 24 into the filter assembly 31 for filtration, so that part of the organic matter, particulate impurities, solid particulate impurities, etc. in the absorbent are removed by the filter unit. The filtered absorbent is passed through the electrodialysis assembly 32 and the resin purification assembly 33 in sequence for purification. Optionally, the filter assembly 31 can be a combination of one or more filters, for example, Figure 1 and Figure 2 As shown, the filter assembly 31 is an activated carbon filter 311 and a microporous filter 312 connected in sequence. The activated carbon filter 311 can remove organic matter, odor, pigments and some heavy metal ions in the absorbent, while the microporous filter 312 can remove solid particles and suspended matter in the absorbent to prevent impurities in the absorbent from contaminating the ion membrane in the electrodialysis reactor 321, which not only extends the service life of the ion membrane, but also improves the desalination efficiency and water quality.

[0043] In addition, the alkali solution outlet 34 can pass an alkaline solution (such as sodium hydroxide, etc.) into the spray component 12. The alkaline solution is mixed with the spray liquid in the spray component 12 and then passed into the washing tower 11, so that the acidity of the spray liquid is reduced, thereby reducing the degree of corrosion of the spray liquid on the conveying pipeline and other contact equipment.

[0044] It should be noted that the absorbent can be an amine liquid for capturing carbon dioxide in flue gas. Accordingly, the absorbent is first passed into the electrodialysis component 32 and then into the resin purification component 33, so that the charged ions in the absorbent can be removed quickly and deeply, while improving the purification efficiency of the absorbent, it can also reduce the processing burden of the resin purification component 33, thereby avoiding premature saturation of the resin tank 331 in the resin purification unit 3, reducing the supporting equipment set for the saturation of the resin tank 331, and reducing the complexity of the overall system. Thus, the waste liquid treatment system for solution purification and recovery of the embodiment of the present invention uses the purification unit 3 to purify the absorbent discharged from the absorption tower 21 through the filter component 31, the electrodialysis component 32 and the resin purification component 33 in sequence, and the alkali solution generated during the purification process is passed into the washing tower 11 so as to be mixed with the spray liquid of the washing tower 11 to neutralize the spray liquid used by the washing tower 11, thereby improving the impurity removal effect of the washing tower 11. In addition, by exchanging heat between the absorbent discharged from the absorption tower 21 and the absorbent discharged from the regeneration tower 22, the absorbent can reduce the temperature of the absorbent discharged from the regeneration tower 22, so that the temperature of the absorbent entering the purification unit 3 reaches an appropriate temperature to improve the purification effect.

[0045] In some embodiments, the waste liquid treatment system for solution purification and recovery of the embodiments of the present invention also includes a concentration component 4, the washing tower 11 has a spray inlet 113 and a spray outlet 114, the spray component 12 is connected to both the spray inlet 113 and the spray outlet 114, the cold side inlet of the concentration component 4 is connected to the spray outlet 114, and the hot side inlet of the concentration component 4 is connected to the regeneration gas outlet of the regeneration tower 22, so that the regeneration gas discharged from the regeneration gas outlet of the regeneration tower 22 enters the concentration component 4 and heats and concentrates the spray liquid.

[0046] It is understandable that if Figure 1 As shown, a portion of the spray liquid after heat exchange with the flue gas in the scrubber 11 is extracted by the spray assembly 12 and passed into the concentration assembly 4, and then the regeneration gas discharged from the regeneration gas outlet is used as a heat source to heat the spray liquid in the concentration assembly 4, thereby achieving heating and concentration of the spray liquid, and further achieving the reuse of the heat of the regeneration gas, and correspondingly reducing the energy consumed by cooling the regeneration gas. The concentration assembly 4 is a device for evaporating and concentrating the solution, such as an evaporator.

[0047] Optionally, the waste liquid treatment system for solution purification and recovery of the embodiment of the present invention also includes a coal powder solidification unit 300, which is connected to the concentration component 4 and the coal-fired power plant boiler 100, so that the concentrated spray liquid can be solidified and crushed with the coal powder, and then sent to the coal-fired power plant boiler 100 through a conveyor for combustion to generate heat for power generation, thereby further avoiding waste of resources and improving the energy utilization rate of the system.

[0048] In some embodiments, the alkali solution outlet 34 is connected to the pipeline between the spray outlet 114 and the cold side inlet of the concentration assembly 4 through a pipeline. Figure 1 and Figure 2 As shown, part of the spray liquid can be mixed with the alkali solution (such as sodium hydroxide) discharged from the alkali solution outlet 34 before entering the concentration component 4, so that the spray liquid and the alkali solution are fully mixed before entering the concentration component 4. In other words, the alkali solution discharged from the alkali solution outlet 34 can react with some substances in the spray liquid, such as neutralizing the acidic substances (sulfuric acid, nitric acid, etc.) in the spray liquid, thereby reducing the acidity of the spray liquid and reducing the corrosion degree of the spray liquid to the conveying pipeline and other contact equipment.

[0049] Preferably, the purification unit 3 further comprises a solution pump 36 , which is disposed on a pipeline between the purification outlet 24 and the filtration inlet 3111 , and is used to extract 10% to 15% of the absorbent in the absorption tower 21 .

[0050] It can be understood that the absorbent comes into contact with the flue gas in the absorption tower 21. Since the absorbent can be used repeatedly, the impurity content in the absorbent will gradually increase. Then, a part of the solution in the absorption tower 21 is extracted by the solution pump 36 and passed into the purification unit 3. The absorbent purified by the purification unit 3 is then passed into the absorption tower 21, thereby avoiding excessive impurity content in the absorbent, thereby ensuring the absorption effect of the absorbent.

[0051] Preferably, the filter assembly 31 includes a filter and a plurality of cache tanks 313, and the plurality of cache tanks 313 are arranged in parallel and connected between the filter and the electrodialysis assembly. It is understandable that the plurality of cache tanks 313 are arranged in parallel, which can increase the overall storage space of the absorbent, and the functions of the cache tanks 313 arranged in parallel or a single cache tank 313 are not affected by the states of other cache tanks 313, and even if a cache tank 313 leaks, is blocked, or other accidents occur, the other cache tanks 313 can still remain safe and can operate normally, thereby reducing the risk of the entire system being shut down due to a single point of failure.

[0052] In some embodiments, the electrodialysis component 32 includes an electrodialysis reactor 321 and a drainage pipeline 322, the fresh water chamber of the electrodialysis reactor 321 is connected to the cache tank 313, one end of the drainage pipeline 322 is connected to the fresh water chamber of the electrodialysis reactor 321, and the other end of the drainage pipeline 322 is connected to the cache tank 313, so that the liquid in the fresh water chamber of the electrodialysis reactor 321 can flow into the cache tank 313 through the drainage pipeline 322.

[0053] Specifically, Figure 1 and Figure 2As shown, a pump is provided on the drainage pipeline 322, and the pump can be started to extract the liquid in the fresh water chamber and pass it into the cache tank 313. It can be understood that the drainage pipeline 322 can be connected to one or more cache tanks 313, that is, the liquid in the fresh water chamber can be extracted and passed into the cache tank 313 for storage by using the drainage pipeline 322. Then, the multiple cache tanks 313 can be divided into two types, one for receiving the absorbent discharged from the filter unit, and the other for receiving the liquid discharged from the fresh water chamber. Therefore, according to the actual working conditions, the absorbent in the cache tank 313 (receiving the absorbent discharged from the filter unit) is passed into the electrodialysis reactor 321, and the first purification treatment of the absorbent is carried out; the liquid in the cache tank 313 (receiving the liquid discharged from the fresh water chamber) is passed into the electrodialysis reactor 321, and the multiple purification functions of the absorbent are carried out.

[0054] In other words, the parallel arrangement of multiple cache tanks 313 can not only realize the storage of absorbent, but also provide storage space for multiple purification treatments of the absorbent to improve the purification effect.

[0055] like Figure 1 and Figure 2 As shown, the electrodialysis assembly also includes a cathode liquid circulation assembly 323 and a waste liquid circulation assembly 324. The cathode liquid circulation assembly 323 includes an cathode liquid tank 3231 and a first pump 3233. The cathode liquid tank 3231, the first pump 3233 and the fresh water chamber are connected by a pipeline. The cathode liquid tank 3231 has a first water injection port 3232. The first water injection port 3232 is used to inject water into the cathode liquid tank 3231. The cathode liquid circulation assembly 323 is connected to the fresh water chamber to transfer the amine solution in the fresh water chamber to the fresh water chamber. The waste liquid circulation component 324 comprises a waste liquid tank 3241 and a second pump 3243, the waste liquid tank 3241, the second pump 3243 and the concentrated water chamber are connected by a pipeline, the waste liquid tank 3241 has a second water injection port 3242, and the second water injection port 3242 is used to inject water into the waste liquid tank 3241, and the waste liquid circulation component 324 is connected to the concentrated water chamber to circulate the amine liquid introduced into the concentrated water chamber between the concentrated water chamber and the waste liquid circulation component 324.

[0056] It can be understood that the purpose of introducing water into the polar liquid tank 3231 and the waste liquid tank 3241 is to provide the required solution for the migration of ions in the absorbent, and to take away the ions that migrate from the concentrated water chamber to the fresh water chamber to ensure the water quality of the fresh water chamber. The concentrated water chamber is used to recycle ions, re-concentrate the ions that migrate to the concentrated water chamber, and provide solution for the next electrodialysis process.

[0057] That is, the extreme liquid circulation component 323 and the waste liquid circulation component 324 can circulate the liquid in the fresh water chamber and the concentrated water chamber using the first pump 3233 and the second pump 3243 respectively, thereby maintaining the performance and efficiency of the system.

[0058] In some embodiments, the resin purification component 33 includes a resin tank 331 and a flushing component 332, the flushing component 332 is connected to the resin tank 331, the alkali solution outlet 34 is located on the resin tank 331, and the alkali solution outlet 34 is connected to the inlet of the buffer tank 313 through a pipeline. The flushing component 332 is used to pass regeneration liquid into the resin tank 331 to flush the resin tank 331 to generate a heat-stable salt solution and alkali solution, and pass the alkali solution in the resin tank 331 into the buffer tank 313.

[0059] Specifically, Figure 1 and Figure 2 As shown, the absorbent discharged from the electrodialysis reactor 321 is passed into the resin tank 331 , and the absorbent can remove the remaining ions of the absorbent by passing through the ion exchange resin in the resin tank 331 , thereby achieving a second purification of the absorbent.

[0060] It is understandable that during the purification of the amine solution by the resin tank 331, the ion exchange resin in the resin tank 331 gradually becomes saturated. By introducing the regeneration liquid into the resin tank 331 by the flushing assembly, the activity of the resin can be restored through ion exchange, and impurities on the resin can also be removed.

[0061] It should be noted that the regeneration liquid can be a mixture of desalted water and an alkaline solution (such as sodium hydroxide solution), and the regeneration liquid contains a small amount of ions, such as sodium ions or hydrogen ions. When the regeneration liquid is passed into the resin tank 331, the ions in the regeneration liquid are exchanged with the ions on the resin, thereby restoring the exchange capacity of the resin. In other words, the resin can be cleaned with desalted water to remove the resin surface and loose particles; the ions in the alkaline solution are exchanged with the ions in the resin to achieve the regeneration of the resin.

[0062] In addition, the inventors found that bound amine ions still exist in the organic amine solution, and the bound amine ions will be removed when passing through the ion exchange resin, which not only causes the loss of amine solution, but also increases the saturation rate of the ion exchange resin, which is not conducive to the purification and recovery of the amine solution. Therefore, taking the MDEA organic amine solution (methyldiethanolamine) as an example, the absorbent will undergo the following reactions during operation:

[0063]

[0064] in, It is a heat stable salt. To bind the amine cation, It is a heat-stable salt anion.

[0065] The waste liquid treatment system for solution purification and recovery of the embodiment of the present invention adds an alkaline solution (sodium hydroxide solution) before the organic amine solution is passed into the electrodialysis reactor 321 to convert the bound amine cations into neutral free amine molecules. When the amine solution enters the electrodialysis module, most of the heat-stable salt anions and sodium ions in the amine solution are quickly removed by the electrodialysis device, and the remaining small amount of heat-stable salt anions and sodium ions are deeply purified by the anion / cation exchange resin method to achieve the purpose of efficiently and deeply removing impurities in the organic amine solution. In addition, the sodium hydroxide solution used for the regeneration of the ion exchange resin is reduced, and the waste sodium hydroxide solution generated can be used to release the bound amine ions of the amine solution, thereby realizing the recovery and recycling of the waste liquid.

[0066] In some embodiments, the resin purification component 33 also includes an alkali storage tank 333 and a regeneration pipeline 334. The flushing component 332 is connected to the alkali storage tank 333 for introducing regeneration liquid into the alkali storage tank 333. One end of the regeneration pipeline 334 is connected to the alkali storage tank 333, and the other end of the regeneration pipeline 334 is connected to the resin tank 331.

[0067] Specifically, Figure 1 As shown, the alkali storage tank 333 is used to store alkaline solutions, such as sodium hydroxide solutions, etc. The flushing component 332 is connected to the alkali storage tank 333 through a pipeline so that the regeneration liquid is passed into the alkali storage tank 333 and the regeneration liquid is mixed with the sodium hydroxide solution, thereby achieving the function of adjusting the sodium hydroxide concentration.

[0068] It is understandable that the alkaline solution in the alkali storage tank 333 is mixed with the regeneration liquid to make the concentration of the alkaline solution adjustable, so as to fully clean the resins with different saturation levels to better remove impurities and pollutants in the resins and ensure that the flushing effect reaches the expected effect. In addition, alkaline solutions of different concentrations can also prevent excessive expansion of the resin and prevent the resin from deforming or falling off due to expansion.

[0069] In other words, the alkali storage tank 333 is used to store alkaline solution, that is, after the resin tank 331 reaches the saturation level, the alkaline solution in the alkali storage tank 333 is passed into the resin tank 331 through the regeneration pipeline 334, so as to flush the resin tank 331, so as to restore the exchange capacity of the resin tank 331. In addition, the flushing component 332 can directly pass the regeneration liquid into the alkali storage tank 333, so that the regeneration liquid is mixed with the alkaline liquid in the alkali storage tank 333, thereby changing the concentration of the alkaline solution in the alkali storage tank 333, so that the resin tanks 331 with different saturation levels can be backflushed to ensure the flushing effect.

[0070] Preferably, the resin purification component 33 further includes an alkali circulation pipeline 335 , which is connected to the alkali storage tank 333 , so that part of the alkali solution in the alkali storage tank 333 can circulate between the alkali circulation pipeline 335 and the alkali storage tank 333 .

[0071] Specifically, Figure 1 As shown, a pump is provided on the alkali circulation pipeline 335, one end of the alkali circulation pipeline 335 is connected to the bottom of the alkali storage tank 333, and the other end of the alkali circulation pipeline 335 is connected to the top of the alkali storage tank 333, so that the pump can be used to extract the alkaline solution near the bottom of the alkali storage tank 333 and pass it into the top position of the alkali storage tank 333, thereby ensuring that the alkaline solution can be more fully mixed under the circulation action of the circulation pipeline, so that the alkaline solution and the regeneration liquid are mixed more evenly.

[0072] That is to say, the alkali circulation pipeline 335 can extract the alkaline liquid in the alkali storage tank 333, and the alkali circulation pipeline 335 discharges the extracted alkaline liquid into the alkali storage tank 333, so as to realize the circulation of the alkaline liquid between the alkali storage tank 333 and the alkali circulation pipeline 335, thereby accelerating the full mixing of the alkaline solution and the regeneration liquid in the alkali storage tank 333.

[0073] In some embodiments, the resin purification assembly 33 further includes a pressurizing member 336, which is connected to the resin tank 331 to pass pressurized gas into the resin tank 331. The pressurizing member 336 can pass a gas with a certain pressure into the resin tank 331, so that a certain pressure can be maintained in the resin tank 331, thereby ensuring the physical state and filtering effect of the resin.

[0074] It should be noted that the pressurized gas introduced by the pressurizing member 336 into the resin tank 331 may be an inert gas such as nitrogen, and the gas pressure range is 0.1MPa to 0.5MPa. In other words, when selecting the pressurized gas, the appropriate gas and pressure may be selected according to factors such as the type of resin, specific requirements of the system, and safety.

[0075] Preferably, there are multiple resin tanks 331, and the multiple resin tanks 331 are arranged in parallel. Figure 1 As shown, multiple parallel resin tanks 331 are provided to ensure the reliability and efficient operation of the amine liquid treatment system, that is, multiple parallel resin tanks 331 can perform amine liquid treatment at the same time. When one resin tank 331 fails or needs maintenance, other parallel resin tanks 331 can continue to work, ensuring the continuous operation of the water treatment system and reducing downtime. In addition, the parallel resin tanks 331 can share the amine liquid treatment load, avoid overloading of a certain resin tank 331, and help extend the service life of the resin.

[0076] Optionally, the flushing assembly 332 includes a flushing outlet 3321 , and the flushing outlet 3321 is connected to the regeneration pipeline 334 and the alkali storage tank 333 through pipelines.

[0077] Specifically, Figure 1As shown, the pipeline connected to the flushing outlet 3321 is divided into two branches, one of which is connected to the alkali storage tank 333 so that the regeneration liquid can directly enter the alkali storage tank 333; the other branch is connected to the regeneration pipeline 334, so that the regeneration liquid discharged from the flushing outlet 3321 can enter the regeneration pipeline 334, and after mixing with the liquid in the regeneration pipeline 334, it can be passed into the resin tank 331. A control valve is provided on the branch, so that when the concentration of the solution adjusted by the alkali storage tank 333 does not meet the requirements, the control valve can be opened to allow the regeneration liquid to be passed into the regeneration pipeline 334 to be directly mixed with the solution, thereby accelerating the concentration adjustment of the alkaline solution.

[0078] That is to say, the flushing outlet 3321 of the flushing component 332 is connected to the regeneration pipeline 334, so that the flushing component 332 can pass the regeneration liquid into the regeneration pipeline 334, and mix it with the alkaline liquid in the regeneration pipeline 334 before passing it into the resin tank 331, thereby further ensuring the concentration of the alkaline liquid passed into the resin tank 331.

[0079] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0080] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0081] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0082] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0083] In the present invention, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0084] Although the above embodiments have been shown and described, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments by those of ordinary skill in the art are all within the scope of protection of the present invention.

Claims

1. A waste liquid treatment system for solution purification and recovery, characterized in that: include: A washing unit, the washing unit comprising a washing tower and a spray assembly, the washing tower having a flue gas inlet and a flue gas outlet, the flue gas inlet being used to introduce flue gas after desulfurization and denitration, the spray assembly being connected to the washing tower so that a spray liquid circulates between the spray assembly and the washing tower, and removes impurities and cools the flue gas in the washing tower; An absorption regeneration unit, the absorption regeneration unit comprising an absorption tower, a regeneration tower and a heat exchanger, the absorption tower having an absorption inlet and an absorption outlet, the regeneration tower having a regeneration inlet and a regeneration outlet, the absorption outlet, the cold side of the heat exchanger and the regeneration inlet are connected by a pipeline, the regeneration outlet, the hot side of the heat exchanger and the absorption inlet are connected by a pipeline, so that the absorbent can circulate between the absorption tower and the regeneration tower; A purification unit, the purification unit comprising a filter assembly, an electrodialysis assembly and a resin purification assembly connected in sequence, the filter assembly having a filter inlet, a purification outlet and a purification inlet on a pipeline between the absorption inlet and the hot side of the heat exchanger, the purification outlet being located upstream of the purification inlet, the filter inlet being communicated with the purification outlet, The resin purification component includes a resin tank and a flushing component, the flushing component is connected to the resin tank, the flushing component is used to pass regeneration liquid into the resin tank to flush the resin tank and generate alkaline solution, the resin tank has an alkaline solution outlet and a clean liquid outlet, the clean liquid outlet is connected to the purification inlet, and the alkaline solution outlet is connected to the spray component; The electrodialysis component comprises an electrodialysis reactor, and before the absorbent enters the electrodialysis reactor, an alkaline solution is added through the alkaline solution outlet.

2. The waste liquid treatment system for solution purification and recovery according to claim 1, characterized in that: It also includes a concentration component, the washing tower has a spray inlet and a spray outlet, the spray component is connected to both the spray inlet and the spray outlet, the cold side inlet of the concentration component is connected to the spray outlet, and the hot side inlet of the concentration component is connected to the regeneration gas outlet of the regeneration tower, so that the regeneration gas discharged from the regeneration gas outlet of the regeneration tower passes into the concentration component and heats and concentrates the spray liquid.

3. The waste liquid treatment system for solution purification and recovery according to claim 2, characterized in that: The alkali solution outlet is connected to the pipeline between the spray outlet and the cold side inlet of the concentration component through a pipeline.

4. The waste liquid treatment system for solution purification and recovery according to claim 3 is characterized in that: The purification unit further comprises a solution pump, which is arranged on a pipeline between the purification outlet and the filtration inlet, and is used to extract 10% to 15% of the absorbent in the absorption tower.

5. The waste liquid treatment system for solution purification and recovery according to claim 4, characterized in that: The filter assembly includes a filter and a plurality of cache tanks, and the plurality of cache tanks are arranged in parallel and connected between the filter and the electrodialysis assembly.

6. The waste liquid treatment system for solution purification and recovery according to claim 5, characterized in that: The electrodialysis component also includes a drainage pipeline. The fresh water chamber of the electrodialysis reactor is connected to the cache tank. One end of the drainage pipeline is connected to the fresh water chamber of the electrodialysis reactor, and the other end of the drainage pipeline is connected to the cache tank, so that the liquid in the fresh water chamber of the electrodialysis reactor can flow into the cache tank through the drainage pipeline.

7. The waste liquid treatment system for solution purification and recovery according to claim 6, characterized in that: The electrodialysis component also includes a pole liquid circulation component and a waste liquid circulation component, the pole liquid circulation component includes a pole liquid tank and a first pump, the pole liquid tank, the first pump and the fresh water chamber of the electrodialysis reactor are connected by a pipeline, the pole liquid tank has a first water injection port, the first water injection port is used to inject water into the pole liquid tank, the pole liquid circulation component is connected to the fresh water chamber of the electrodialysis reactor, so as to circulate the absorbent in the fresh water chamber of the electrodialysis reactor between the fresh water chamber of the electrodialysis reactor and the pole liquid circulation component; The waste liquid circulation component includes a waste liquid tank and a second pump, the waste liquid tank, the second pump and the concentrated water chamber of the electrodialysis reactor are connected by a pipeline, the waste liquid tank has a second water injection port, the second water injection port is used to inject water into the waste liquid tank, the waste liquid circulation component is connected to the concentrated water chamber of the electrodialysis reactor to circulate the absorbent in the concentrated water chamber of the electrodialysis reactor between the concentrated water chamber of the electrodialysis reactor and the waste liquid circulation component.

8. The waste liquid treatment system for solution purification and recovery according to any one of claims 1 to 7, characterized in that: The resin purification component also includes an alkali storage tank and a regeneration pipeline. The flushing component is connected to the alkali storage tank for introducing regeneration liquid into the alkali storage tank. One end of the regeneration pipeline is connected to the alkali storage tank, and the other end of the regeneration pipeline is connected to the resin tank.

9. The waste liquid treatment system for solution purification and recovery according to claim 8, characterized in that: The resin purification component also includes an alkali circulation pipeline, which is connected to the alkali storage tank so that part of the alkali solution in the alkali storage tank can circulate between the alkali circulation pipeline and the alkali storage tank.

10. The waste liquid treatment system for solution purification and recovery according to claim 9, characterized in that: The resin purification assembly further includes a pressurizing member, which is connected to the resin tank and is used to introduce pressurized gas into the resin tank.

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