Carbon dioxide absorbent regeneration system and method

Abstract

The application discloses a carbon dioxide absorbent regeneration system, which comprises a filter, an electrodialysis regeneration device, a concentrated chamber waste liquid kettle, a plurality of valves and a pump. The inlet and outlet of the electrodialysis regeneration device can be switched by opening and closing the valves, and the pump and the concentrated chamber waste liquid kettle are used to input lye into the electrodialysis regeneration device. The application also provides a carbon dioxide absorbent regeneration method, which is operated in the system, removes heat stable salts in the carbon dioxide absorbent, and thus realizes regeneration of the carbon dioxide absorbent. The carbon dioxide absorbent regeneration system provided by the application can effectively remove ions deposited on the surface of an ion exchange membrane in the electrodialysis regeneration device during operation, prolongs the service life of the ion exchange membrane, controls the ion concentration in the concentrated chamber and the dilute chamber of the electrodialysis regeneration device, and obtains a higher amine recovery rate and heat stable salt removal rate. The carbon dioxide absorbent regeneration method provided by the application can also recycle heat stable salts.

Description

Technical Field

[0001] This invention relates to a carbon dioxide absorbent regeneration system and method. Background Technology

[0002] CO2 capture, utilization, and storage (CCUS) technology is one of the most effective means of achieving large-scale carbon emission reduction. Solvent-based CO2 capture technology has advantages such as good separation efficiency and mature, reliable technology. It mainly utilizes a solution primarily composed of organic amines to absorb carbon dioxide through a physicochemical reaction, followed by regeneration in a regeneration tower. During regeneration, reactions with components in the flue gas are inevitable, generating thermally stable salts, causing amine loss and affecting absorption efficiency. The main methods for removing thermally stable salts from the amine solution include distillation, ion exchange, and electrodialysis. Compared to other methods, electrodialysis is highly efficient and has simple equipment, making it a more widely accepted technology.

[0003] Chinese patent authorization number "CN112742176A" discloses "a method and apparatus for purifying and removing heat-stable salts from amine solution". After the electrochemical adsorption electrode is saturated, the electrode is backwashed with deionized water or low-concentration amine solution. The resulting concentrated solution is filtered and further desalted by electrodialysis, and the amine solution is recovered.

[0004] Chinese patent application CN112495189 discloses a method for removing HSS during DETA carbon capture via three-compartment electrodialysis. This method uses a decarbonized organic amine solution containing sulfate as the feed solution, a sodium hydroxide solution as the alkali solution, deionized water as the salt solution, and a sodium sulfate electrolyte solution as the electrode solution. The solution is pumped into an electrodialysis unit with multiple membrane units using a centrifugal pump. Under an applied electric field, thermally stable anions in the feed solution migrate through anion exchange membranes to the salt chamber and are discharged. Simultaneously, hydroxide ions in the alkali chamber pass through anion exchange membranes into the feed chamber, converting the bound protonated amine into free amine, thereby regenerating the organic amine.

[0005] Although existing electrodialysis methods can effectively reduce the content of thermally stable salts in amine solutions, they also have problems such as large losses during amine regeneration and difficulty in recovering thermally stable salts from the concentrated solution after regeneration. Summary of the Invention

[0006] This invention addresses the problems of high amine loss and excessive wastewater generation in existing carbon dioxide absorbent regeneration technologies. Based on a two-compartment electrodialysis system, it effectively reduces amine loss during electrodialysis by adjusting the concentration of the brine in the concentration chamber. Simultaneously, by adjusting the composition of the brine in the concentration chamber, heat-stable salts can be purified through crystallization, further enhancing the purification effect of electrodialysis and reducing amine loss. During the electrodialysis cycle, this invention automatically switches the inlet and outlet directions of the electrodialysis system via valves, effectively reducing electron deposition on the anion and cation membranes and significantly extending the lifespan of the electrodialysis membrane stack.

[0007] As one aspect of the present invention, a carbon dioxide absorbent regeneration system is disclosed, comprising: a filter 1, valves 2, 3, 4, and 5; an electrodialysis regeneration device 6; a concentrate chamber waste vessel 7; a pump 8; and a pump 9; wherein one end of the pump 8 is connected to the filter 1, and the other end of the pump 8 is connected to valves 2 and 3; valve 2 is connected to the bottom of the electrodialysis regeneration device 6; valve 3 is connected to the top of the electrodialysis regeneration device 6; valve 4 is connected to the top of the electrodialysis regeneration device 6; valve 5 is connected to the bottom of the electrodialysis regeneration device 6; one end of the pump 9 is connected to the concentrate chamber waste vessel 7; and the other end of the pump 9 is connected to the bottom of the electrodialysis regeneration device 6.

[0008] In a feasible specific implementation, the filter 1 is a Y-type filter.

[0009] As another aspect of the present invention, a method for regenerating a carbon dioxide absorbent, operated in the aforementioned system, the method comprising:

[0010] (1) Open valves 2 and 4, close valves 3 and 5, and turn on pump 8. At this time, the carbon dioxide absorbent to be regenerated, which has been filtered and purified by the filter, flows into the bottom of the electrodialysis regeneration device 6 through pump 8 and valve 2.

[0011] (2) An alkaline solution is prepared in the concentrated waste liquid tank 7. The pump 9 is turned on. At this time, the alkaline solution in the concentrated waste liquid tank 7 flows into the bottom of the electrodialysis regeneration device 6 through the pump 9.

[0012] (3) Turn on the power switch of the electrodialysis regeneration device 6 to perform electrodialysis. The preliminarily purified carbon dioxide absorbent flows out from the top of the electrodialysis regeneration device 6 through the valve 4.

[0013] (4) Close valves 2 and 4, and open valves 3 and 5. At this time, the pre-purified carbon dioxide absorbent enters from the top of the electrodialysis regeneration device 6 through pump 8 and valve 3, and continues to run electrodialysis. The regenerated carbon dioxide absorbent flows out from the bottom of the electrodialysis regeneration device 6 through valve 5.

[0014] In a specific implementation, the power supply voltage of the electrodialysis regeneration device 6 is set to 0.5–15V.

[0015] In a specific implementation, the power supply voltage of the electrodialysis regeneration device 6 is preferably set to 3-15V.

[0016] In a specific implementation, the concentration of the alkaline solution prepared in the concentrated waste liquid tank 7 is 0.1 to 1 mol / L.

[0017] In a specific implementation, the alkaline solution prepared in the concentrated waste liquid tank 7 is one of KOH solution, K2CO3 solution and KHCO3 solution or any combination thereof.

[0018] In a specific implementation, the carbon dioxide absorbent regeneration method further includes the recovery of heat-stable salts: the waste liquid in the concentrate chamber waste liquid vessel 7 is treated using an evaporator crystallizer, and evaporated and crystallized at 100-120°C for 60-240 minutes. After cooling, heat-stable salts and an aqueous phase are obtained. After adding KOH to the aqueous phase, it is returned to the concentrate chamber waste liquid vessel 7 for continued use.

[0019] In a specific implementation, the evaporator crystallizer is a DTB type evaporator, a forced circulation type evaporator, or an Oslo type evaporator.

[0020] As another aspect of the present invention, it relates to the application of the above-mentioned carbon dioxide absorbent regeneration method in carbon dioxide capture, utilization and storage technology.

[0021] The carbon dioxide absorbent regeneration method provided by this invention utilizes an electrodialysis device for effective regeneration and recovery of the absorbent. By adjusting the concentration of the salt solution in the concentration chamber, amine loss can be significantly reduced. During the electrodialysis cycle, this invention automatically switches the inlet and outlet directions of the electrodialysis system via valves, thereby effectively reducing electron precipitation on the anion and cation membranes and significantly extending the lifespan of the electrodialysis membrane stack. Furthermore, by adding crystallized, heat-stabilized salts can be recycled as products, improving the resource recovery rate of the carbon dioxide absorbent and achieving a high amine recovery rate. Attached Figure Description

[0022] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0023] Figure 1 This is a schematic diagram of a carbon dioxide absorbent regeneration system according to an embodiment of the present invention;

[0024] Wherein: 1 is a filter, 2-5 are valves, 6 is an electrodialysis regeneration device, 7 is a concentrate chamber waste liquid tank, and 8 and 9 are pumps. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1

[0027] The carbon dioxide absorbent regeneration system in this embodiment can be referred to... Figure 1 ,like Figure 1 As shown, the system includes a filter 1, valves 2, 3, 4, and 5, an electrodialysis regeneration device 6, a concentrate chamber waste liquid tank 7, a pump 8, and a pump 9. One end of pump 8 is connected to the filter 1, and the other end is connected to valves 2 and 3. Valve 2 is connected to the bottom of the electrodialysis regeneration device 6, valve 3 is connected to the top of the electrodialysis regeneration device 6, valve 4 is connected to the top of the electrodialysis regeneration device 6, and valve 5 is connected to the bottom of the electrodialysis regeneration device 6. One end of pump 9 is connected to the concentrate chamber waste liquid tank 7, and the other end is connected to the bottom of the electrodialysis regeneration device 6. An alkaline solution is prepared in the concentrate chamber waste liquid tank 7.

[0028] The electrodialysis regeneration device 6 used in this embodiment of the invention refers to the working principle of the electrodialyzer described on pages 6-7 of the book "Electrodialysis Engineering" (published by Science Press in 1995, authored by Zhang Weirun). The electrodialysis regeneration device 6 includes multiple electrodialysis membrane stacks and a power source. Each electrodialysis membrane stack is composed of alternating cation exchange membranes, desalination chamber partitions, anion exchange membranes, and concentration chamber partitions. One set constitutes one membrane stack, and several membranes are stacked together. Electrode chamber partitions are added to both sides to form a membrane stack, with 10 pairs of membrane stacks. Electrodes, a water distribution plate, and a clamping plate are placed on both sides of the membrane stack to form the electrodialysis membrane stack. Other details are not elaborated further.

[0029] Calculation of heat-stable salt removal rate:

[0030] Heat-stable salt (HSS) removal rate = (concentration of heat-stable salt in the carbon dioxide absorbent to be regenerated - concentration of heat-stable salt in the regenerated carbon dioxide absorbent) / concentration of heat-stable salt in the carbon dioxide absorbent to be regenerated × 100%.

[0031] Calculation of amine recovery rate in carbon dioxide absorbent:

[0032] The recovery rate of amines in carbon dioxide absorbent = the concentration of amines in the regenerated carbon dioxide absorbent / the concentration of amines in the carbon dioxide absorbent to be regenerated.

[0033] In this embodiment, the carbon dioxide absorbent to be regenerated is an amine solution, wherein the concentration of amine is 50% and the concentration of heat-stable salt is 3% (determined by ion chromatography).

[0034] Regeneration of carbon dioxide absorbent:

[0035] (1) The carbon dioxide absorbent to be regenerated is filtered and impurities are removed by filter 1, which is a Y-type filter;

[0036] (2) Open valves 2 and 4, close valves 3 and 5, turn on pump 8, and set the flow rate to 20L / h. At this time, the carbon dioxide absorbent to be regenerated after being filtered and cleaned flows into the bottom of the electrodialysis regeneration device 6 through pump 8 and valve 2.

[0037] (3) Prepare a 0.1 mol / L KOH solution in the concentrated waste liquid tank 7, turn on pump 9 and set the flow rate to 20 L / h; after pumps 8 and 9 are running stably, turn on the power switch of the electrodialysis regeneration device 6 and set the voltage to 5V. The electrodialysis regeneration device 6 runs for 180 minutes and the regenerated carbon dioxide absorbent flows out from the top of the electrodialysis regeneration device 6 through valve 4.

[0038] The concentration of amine in the regenerated carbon dioxide absorbent was 49%, and the concentration of heat-stable salt was 0.15%; the recovery rate of amine in the carbon dioxide absorbent was 98%, and the removal rate of heat-stable salt was 95%.

[0039] Recovery of heat-stabilized salts:

[0040] After running the carbon dioxide regeneration system of this embodiment 10 times and regenerating 10 batches of carbon dioxide absorbent, the concentration of heat-stable salts in the waste liquid in the concentration chamber waste liquid tank 7 increased to more than 27 wt%. The waste liquid in the concentration chamber waste liquid tank 7 was then subjected to evaporation and crystallization treatment using a DTB type evaporator at 100°C for 120 min. After cooling, heat-stable salts and an aqueous phase were obtained. The concentration of heat-stable salts in the aqueous phase decreased to below 0.5%. KOH was added to the aqueous phase until the pH reached 13, and the solution was then returned to the concentration chamber waste liquid tank 7 for reuse.

[0041] Example 2

[0042] The carbon dioxide absorbent regeneration system in this embodiment is the same as that in Embodiment 1, and can be referred to accordingly. Figure 1 .

[0043] In this embodiment, the carbon dioxide absorbent to be regenerated is an amine solution, wherein the concentration of amine is 50 wt% and the concentration of heat-stable salt is 3 wt% (determined by ion chromatography).

[0044] Regeneration of carbon dioxide absorbent:

[0045] (1) The carbon dioxide absorbent to be regenerated is filtered and impurities are removed by filter 1, which is a Y-type filter;

[0046] (2) Open valves 2 and 4, close valves 3 and 5, turn on pump 8, and set the flow rate to 20L / h. At this time, the carbon dioxide absorbent to be regenerated after being filtered and cleaned flows into the bottom of the electrodialysis regeneration device 6 through pump 8 and valve 2.

[0047] (3) Prepare a KOH solution with a concentration of 0.1 mol / L in the concentrated waste liquid tank 7, turn on pump 9 and set the flow rate to 20 L / h; after pump 8 and pump 9 are running stably, turn on the power switch of electrodialysis regeneration device 6 and set the voltage to 5V. Electrodialysis regeneration device 6 runs for 90 minutes and the preliminarily purified carbon dioxide absorbent flows out from the top of electrodialysis regeneration device 6 through valve 4.

[0048] (4) Close valves 2 and 4, and open valves 3 and 5. At this time, the pre-purified carbon dioxide absorbent enters from the top of the electrodialysis regeneration device 6 through pump 8 and valve 3. The electrodialysis regeneration device 6 continues to run for 90 minutes and flows out from the bottom of the electrodialysis regeneration device 6 through valve 5.

[0049] The concentration of amine in the regenerated carbon dioxide absorbent was 49%, and the concentration of heat-stable salt was 0.06%; the recovery rate of amine in the carbon dioxide absorbent was 98%, and the removal rate of heat-stable salt was 98%.

[0050] Recovery of heat-stabilized salts:

[0051] After running the carbon dioxide regeneration system of this embodiment 10 times and regenerating 10 batches of carbon dioxide absorbent, the concentration of heat-stable salt in the waste liquid in the concentration chamber waste liquid tank 7 increased to more than 30 wt%. The waste liquid in the concentration chamber waste liquid tank 7 was then subjected to evaporation and crystallization treatment using a DTB type evaporator at 120°C for 60 min. After cooling, heat-stable salt and aqueous phase were obtained. The concentration of heat-stable salt in the aqueous phase decreased to below 0.7 wt%. KOH was added to the aqueous phase until the pH reached 13, and then the solution was returned to the concentration chamber waste liquid tank 7 for reuse.

[0052] By switching valves and adjusting the inlet and outlet of the electrodialysis system, the removal rate of heat-stable salts can be effectively improved, while maintaining a high amine recovery rate.

[0053] Example 3

[0054] The carbon dioxide absorbent regeneration system in this embodiment is the same as that in Embodiment 1, and can be referred to accordingly. Figure 1 .

[0055] In this embodiment, the carbon dioxide absorbent to be regenerated is an amine solution, wherein the concentration of amine is 50 wt% and the concentration of heat-stable salt is 3 wt% (determined by ion chromatography).

[0056] Regeneration of carbon dioxide absorbent:

[0057] (1) The carbon dioxide absorbent to be regenerated is filtered and impurities are removed by filter 1, which is a Y-type filter;

[0058] (2) Open valves 2 and 4, close valves 3 and 5, turn on pump 8, and set the flow rate to 20L / h. At this time, the carbon dioxide absorbent to be regenerated after being filtered and cleaned flows into the bottom of the electrodialysis regeneration device 6 through pump 8 and valve 2.

[0059] (3) Prepare a KOH solution with a concentration of 0.1 mol / L in the concentrated waste liquid tank 7, turn on pump 9 and set the flow rate to 20 L / h; after pump 8 and pump 9 are running stably, turn on the power switch of the electrodialysis regeneration device 6 and set the voltage to 0.5V. The electrodialysis regeneration device 6 runs for 90 minutes, and the preliminarily purified carbon dioxide absorbent flows out from the top of the electrodialysis regeneration device 6 through valve 4.

[0060] (4) Close valves 2 and 4, and open valves 3 and 5. At this time, the pre-purified carbon dioxide absorbent enters from the top of the electrodialysis regeneration device 6 through pump 8 and valve 3. The electrodialysis regeneration device 6 continues to run for 90 minutes and flows out from the bottom of the electrodialysis regeneration device 6 through valve 5.

[0061] The concentration of amine in the regenerated carbon dioxide absorbent was 49%, and the concentration of heat-stable salt was 0.6%; the recovery rate of amine in the carbon dioxide absorbent was 98%, and the removal rate of heat-stable salt was 80%.

[0062] Recovery of heat-stabilized salts:

[0063] After running the carbon dioxide regeneration system of this embodiment 10 times and regenerating 10 batches of carbon dioxide absorbent, the concentration of heat-stable salts in the waste liquid in the concentration chamber waste liquid tank 7 can be increased to more than 30 wt%. The waste liquid in the concentration chamber waste liquid tank 7 is then subjected to evaporation and crystallization treatment using a DTB type evaporator at 120°C for 120 min. After cooling, heat-stable salts and an aqueous phase are obtained. The concentration of heat-stable salts in the aqueous phase is reduced to below 0.3 wt%. After adding KOH to the aqueous phase until the pH reaches 13, it is returned to the concentration chamber waste liquid tank 7 for reuse.

[0064] Example 4

[0065] The carbon dioxide absorbent regeneration system in this embodiment is the same as that in Embodiment 1, and can be referred to accordingly. Figure 1 .

[0066] In this embodiment, the carbon dioxide absorbent to be regenerated is an amine solution, wherein the concentration of amine is 50 wt% and the concentration of heat-stable salt is 3 wt% (determined by ion chromatography).

[0067] Regeneration of carbon dioxide absorbent:

[0068] (1) The carbon dioxide absorbent to be regenerated is filtered and impurities are removed by filter 1, which is a Y-type filter;

[0069] (2) Open valves 2 and 4, close valves 3 and 5, turn on pump 8, and set the flow rate to 20L / h. At this time, the carbon dioxide absorbent to be regenerated after being filtered and cleaned flows into the bottom of the electrodialysis regeneration device 6 through pump 8 and valve 2.

[0070] (3) Prepare a 0.1 mol / L KOH solution in the concentrated waste liquid tank 7, turn on pump 9 and set the flow rate to 20 L / h; after pump 8 and pump 9 are running stably, turn on the power switch of electrodialysis regeneration device 6 and set the voltage to 15V. Electrodialysis regeneration device 6 runs for 90 minutes and the preliminarily purified carbon dioxide absorbent flows out from the top of electrodialysis regeneration device 6 through valve 4.

[0071] (4) Close valves 2 and 4, and open valves 3 and 5. At this time, the pre-purified carbon dioxide absorbent enters from the top of the electrodialysis regeneration device 6 through pump 8 and valve 3. The electrodialysis regeneration device 6 continues to run for 90 minutes and flows out from the bottom of the electrodialysis regeneration device 6 through valve 5.

[0072] The concentration of amine in the regenerated carbon dioxide absorbent was 48%, and the concentration of heat-stable salt was 0.01%. The recovery rate of amine in the carbon dioxide absorbent was 96%, and the removal rate of heat-stable salt was 99.7%.

[0073] Recovery of heat-stabilized salts:

[0074] After running the carbon dioxide regeneration system of this embodiment 10 times and regenerating 10 batches of carbon dioxide absorbent, the concentration of heat-stable salts in the waste liquid in the concentration chamber waste liquid tank 7 increased to more than 30 wt%. The waste liquid in the concentration chamber waste liquid tank 7 was then subjected to evaporation and crystallization treatment using a DTB type evaporator at 100°C for 240 min. After cooling, heat-stable salts and an aqueous phase were obtained. The concentration of heat-stable salts in the aqueous phase decreased to below 0.3 wt%. KOH was added to the aqueous phase until the solution pH reached 13, and then the solution was returned to the concentration chamber waste liquid tank 7 for reuse.

[0075] Example 5

[0076] The carbon dioxide absorbent regeneration system in this embodiment is the same as that in Embodiment 1, and can be referred to accordingly. Figure 1 .

[0077] In this embodiment, the carbon dioxide absorbent to be regenerated is an amine solution, wherein the concentration of amine is 30 wt% and the concentration of heat-stable salt is 3 wt% (determined by ion chromatography).

[0078] Regeneration of carbon dioxide absorbent:

[0079] (1) The carbon dioxide absorbent to be regenerated is filtered and impurities are removed by filter 1, which is a Y-type filter;

[0080] (2) Open valves 2 and 4, close valves 3 and 5, turn on pump 8, and set the flow rate to 20L / h. At this time, the carbon dioxide absorbent to be regenerated after being filtered and cleaned flows into the bottom of the electrodialysis regeneration device 6 through pump 8 and valve 2.

[0081] (3) Prepare a 0.1 mol / L KOH solution in the concentrated waste liquid tank 7, turn on pump 9 and set the flow rate to 20 L / h; after pump 8 and pump 9 are running stably, turn on the power switch of electrodialysis regeneration device 6 and set the voltage to 15V. Electrodialysis regeneration device 6 runs for 90 minutes and the preliminarily purified carbon dioxide absorbent flows out from the top of electrodialysis regeneration device 6 through valve 4.

[0082] (4) Close valves 2 and 4, and open valves 3 and 5. At this time, the pre-purified carbon dioxide absorbent enters from the top of the electrodialysis regeneration device 6 through pump 8 and valve 3. The electrodialysis regeneration device 6 continues to run for 90 minutes and flows out from the bottom of the electrodialysis regeneration device 6 through valve 5.

[0083] The concentration of amine in the regenerated carbon dioxide absorbent was 29.1%, and the concentration of heat-stable salt was 0.01%. The recovery rate of amine in the carbon dioxide absorbent was 97%, and the removal rate of heat-stable salt was 99.7%.

[0084] Recovery of heat-stabilized salts:

[0085] After running the carbon dioxide regeneration system of this embodiment 10 times and regenerating 10 batches of carbon dioxide absorbent, the concentration of heat-stable salts in the waste liquid in the concentration chamber waste liquid tank 7 increases to more than 30 wt%. The waste liquid in the concentration chamber waste liquid tank 7 is then subjected to evaporation and crystallization treatment using a forced circulation evaporator at 100°C for 120 min. After cooling, heat-stable salts and an aqueous phase are obtained. The concentration of heat-stable salts in the aqueous phase drops to below 0.5 wt%. KOH is added to the aqueous phase until the pH reaches 13, and then the phase is returned to the concentration chamber waste liquid tank 7 for reuse.

[0086] Example 6

[0087] The carbon dioxide absorbent regeneration system in this embodiment is the same as that in Embodiment 1, and can be referred to accordingly. Figure 1 .

[0088] In this embodiment, the carbon dioxide absorbent to be regenerated is an amine solution, wherein the concentration of amine is 30 wt% and the concentration of heat-stable salt is 3 wt% (determined by ion chromatography).

[0089] Regeneration of carbon dioxide absorbent:

[0090] (1) The carbon dioxide absorbent to be regenerated is filtered and impurities are removed by filter 1, which is a Y-type filter;

[0091] (2) Open valves 2 and 4, close valves 3 and 5, turn on pump 8, and set the flow rate to 20L / h. At this time, the carbon dioxide absorbent to be regenerated after being filtered and cleaned flows into the bottom of the electrodialysis regeneration device 6 through pump 8 and valve 2.

[0092] (3) Prepare a K2CO3 solution with a concentration of 1 mol / L in the concentrated waste liquid tank 7, turn on pump 9 and set the flow rate to 20 L / h; after pump 8 and pump 9 are running stably, turn on the power switch of electrodialysis regeneration device 6 and set the voltage to 15V. Electrodialysis regeneration device 6 runs for 90 minutes, and the preliminarily purified carbon dioxide absorbent flows out from the top of electrodialysis regeneration device 6 through valve 4.

[0093] (4) Close valves 2 and 4, and open valves 3 and 5. At this time, the pre-purified carbon dioxide absorbent enters from the top of the electrodialysis regeneration device 6 through pump 8 and valve 3. The electrodialysis regeneration device 6 continues to run for 90 minutes and flows out from the bottom of the electrodialysis regeneration device 6 through valve 5.

[0094] The concentration of amine in the regenerated carbon dioxide absorbent was 29.7%, and the concentration of heat-stable salt was 0.06%. The recovery rate of amine in the carbon dioxide absorbent was 99%, and the removal rate of heat-stable salt was 98%.

[0095] Recovery of heat-stabilized salts:

[0096] After running the carbon dioxide regeneration system of this embodiment 10 times and regenerating 10 batches of carbon dioxide absorbent, the concentration of heat-stable salts in the waste liquid in the concentration chamber waste liquid tank 7 can be increased to more than 30 wt%. The waste liquid in the concentration chamber waste liquid tank 7 is then subjected to evaporation and crystallization treatment using an Oslo-type evaporator at 100°C for 120 min. After cooling, heat-stable salts and an aqueous phase are obtained. The concentration of heat-stable salts in the aqueous phase can be reduced to below 0.5 wt%. After adding KOH to the aqueous phase until the pH is 13, it is returned to the concentration chamber waste liquid tank 7 for reuse.

[0097] Example 7

[0098] The carbon dioxide absorbent regeneration system in this embodiment is the same as that in Embodiment 1, and can be referred to accordingly. Figure 1 .

[0099] In this embodiment, the carbon dioxide absorbent to be regenerated is an amine solution, wherein the concentration of amine is 30 wt% and the concentration of heat-stable salt is 3 wt% (determined by ion chromatography).

[0100] Regeneration of carbon dioxide absorbent:

[0101] (1) The carbon dioxide absorbent to be regenerated is filtered and impurities are removed by filter 1, which is a Y-type filter;

[0102] (2) Open valves 2 and 4, close valves 3 and 5, turn on pump 8, and set the flow rate to 20L / h. At this time, the carbon dioxide absorbent to be regenerated after being filtered and cleaned flows into the bottom of the electrodialysis regeneration device 6 through pump 8 and valve 2.

[0103] (3) Prepare a 1 mol / L KHCO3 solution in the concentrated waste liquid tank 7, turn on pump 9 and set the flow rate to 20 L / h; after pump 8 and pump 9 are running stably, turn on the power switch of electrodialysis regeneration device 6 and set the voltage to 3V. Electrodialysis regeneration device 6 runs for 90 minutes and the preliminarily purified carbon dioxide absorbent flows out from the top of electrodialysis regeneration device 6 through valve 4.

[0104] (4) Close valves 2 and 4, and open valves 3 and 5. At this time, the pre-purified carbon dioxide absorbent enters from the top of the electrodialysis regeneration device 6 through pump 8 and valve 3. The electrodialysis regeneration device 6 continues to run for 90 minutes and flows out from the bottom of the electrodialysis regeneration device 6 through valve 5.

[0105] The concentration of amine in the regenerated carbon dioxide absorbent was 29.4%, and the concentration of heat-stable salt was 0.09%. The recovery rate of amine in the carbon dioxide absorbent was 98%, and the removal rate of heat-stable salt was 97%.

[0106] Recovery of heat-stabilized salts:

[0107] After running the carbon dioxide regeneration system of this embodiment 10 times and regenerating 10 batches of carbon dioxide absorbent, the concentration of heat-stable salts in the waste liquid in the concentration chamber waste liquid tank 7 increased to more than 30%. The waste liquid in the concentration chamber waste liquid tank 7 was then subjected to evaporation and crystallization treatment using an Oslo-type evaporator at 100°C for 120 minutes. After cooling, heat-stable salts and an aqueous phase were obtained. The concentration of heat-stable salts in the aqueous phase decreased to below 0.5 wt%. KOH was added to the aqueous phase until the pH reached 13, and then the phase was returned to the concentration chamber waste liquid tank 7 for reuse.

[0108] Example 8

[0109] The carbon dioxide absorbent regeneration system in this embodiment is the same as that in Embodiment 1, and can be referred to accordingly. Figure 1 .

[0110] In this embodiment, the carbon dioxide absorbent to be regenerated is an amine solution, wherein the concentration of amine is 30 wt% and the concentration of heat-stable salt is 3 wt% (determined by ion chromatography).

[0111] Regeneration of carbon dioxide absorbent:

[0112] (1) The carbon dioxide absorbent to be regenerated is filtered and impurities are removed by filter 1, which is a Y-type filter;

[0113] (2) Open valves 2 and 4, close valves 3 and 5, turn on pump 8, and set the flow rate to 20L / h. At this time, the carbon dioxide absorbent to be regenerated after being filtered and cleaned flows into the bottom of the electrodialysis regeneration device 6 through pump 8 and valve 2.

[0114] (3) Prepare a 1 mol / L KOH solution in the concentrated waste liquid tank 7, turn on pump 9 and set the flow rate to 20 L / h; after pump 8 and pump 9 are running stably, turn on the power switch of electrodialysis regeneration device 6 and set the voltage to 10V. Electrodialysis regeneration device 6 runs for 90 minutes and the preliminarily purified carbon dioxide absorbent flows out from the top of electrodialysis regeneration device 6 through valve 4.

[0115] (4) Close valves 2 and 4, and open valves 3 and 5. At this time, the pre-purified carbon dioxide absorbent enters from the top of the electrodialysis regeneration device 6 through pump 8 and valve 3. The electrodialysis regeneration device 6 continues to run for 90 minutes and flows out from the bottom of the electrodialysis regeneration device 6 through valve 5.

[0116] The concentration of amine in the regenerated carbon dioxide absorbent was 28.5%, and the concentration of heat-stable salt was 0.03%. The recovery rate of amine in the carbon dioxide absorbent was 95%, and the removal rate of heat-stable salt was 99%.

[0117] Recovery of heat-stabilized salts:

[0118] After running the carbon dioxide regeneration system of this embodiment 10 times and regenerating 10 batches of carbon dioxide absorbent, the concentration of heat-stable salt in the waste liquid in the concentration chamber waste liquid tank 7 increased to more than 30 wt%. The waste liquid in the concentration chamber waste liquid tank 7 was then subjected to evaporation and crystallization treatment using an Oslo-type evaporator at 100°C for 120 min. After cooling, heat-stable salt and aqueous phase were obtained. The concentration of heat-stable salt in the aqueous phase decreased to below 0.5 wt%. KOH was added to the aqueous phase until the pH reached 13, and then the solution was returned to the concentration chamber waste liquid tank 7 for reuse.

[0119] Comparative Example 1

[0120] The carbon dioxide absorbent regeneration system in this comparative example can be referenced. Figure 1 The difference from Example 1 is that water is provided in the concentrated waste liquid tank 7.

[0121] The carbon dioxide absorbent to be regenerated in this comparative example is an amine solution with an amine concentration of 50 wt% and a heat-stable salt concentration of 3 wt% (determined by ion chromatography).

[0122] Regeneration of carbon dioxide absorbent:

[0123] (1) The carbon dioxide absorbent to be regenerated is filtered and impurities are removed by filter 1, which is a Y-type filter;

[0124] (2) Open valves 2 and 4, close valves 3 and 5, turn on pump 8, and set the flow rate to 20L / h. At this time, the carbon dioxide absorbent to be regenerated after being filtered and cleaned flows into the bottom of the electrodialysis regeneration device 6 through pump 8 and valve 2.

[0125] (3) Water is prepared in the concentrated waste liquid tank 7, pump 9 is turned on and the flow rate is set to 20L / h; after pump 8 and pump 9 are running stably, the power switch of the electrodialysis regeneration device 6 is turned on and the voltage is set to 5V. The electrodialysis regeneration device 6 runs for 180 minutes and the regenerated carbon dioxide absorbent flows out from the top of the electrodialysis regeneration device 6 through valve 4.

[0126] The concentration of amine in the regenerated carbon dioxide absorbent was 42.5%, and the concentration of heat-stable salt was 0.21%. The recovery rate of amine in the carbon dioxide absorbent was 85%, and the removal rate of heat-stable salt was 93%.

[0127] As can be seen from the above examples and comparative examples, the amine recovery rate of Examples 1-8 is 95%-99%, and the heat-stable salt removal rate is 80%-99.7%, both of which are higher. By switching the inlet and outlet of the electrodialysis regeneration device through valves and pumping alkaline solution into the electrodialysis regeneration device, the ion concentrations in the concentrated and dilute chambers of the electrodialysis regeneration device are made comparable, thereby improving the electrodialysis efficiency. At the same time, it effectively removes ions deposited on the surface of the ion exchange membrane in the electrodialysis regeneration device, extends the service life of the ion exchange membrane, and further improves the electrodialysis efficiency.

[0128] The carbon dioxide absorbent regeneration systems of Examples 1-8 can be summarized as follows:

[0129] The carbon dioxide absorbent regeneration system includes a filter 1, valves 2, 3, 4, and 5, an electrodialysis regeneration device 6, a concentrate chamber waste vessel 7, a pump 8, and a pump 9. One end of pump 8 is connected to filter 1, and the other end of pump 8 is connected to valves 2 and 3. Valve 2 is connected to the bottom of electrodialysis regeneration device 6, valve 3 is connected to the top of electrodialysis regeneration device 6, valve 4 is connected to the top of electrodialysis regeneration device 6, and valve 5 is connected to the bottom of electrodialysis regeneration device 6. One end of pump 9 is connected to the concentrate chamber waste vessel 7, and the other end of pump 9 is connected to the bottom of electrodialysis regeneration device 6.

[0130] Among them, filter 1 is a Y-type filter.

[0131] The carbon dioxide absorbent regeneration methods in Examples 1-8 can be summarized as follows:

[0132] (1) Open valves 2 and 4, close valves 3 and 5, and turn on pump 8. At this time, the carbon dioxide absorbent to be regenerated, which has been filtered and purified by the filter, flows into the bottom of the electrodialysis regeneration device 6 through pump 8 and valve 2.

[0133] (2) An alkaline solution is prepared in the concentrated waste liquid tank 7. The pump 9 is turned on. At this time, the alkaline solution in the concentrated waste liquid tank 7 flows into the bottom of the electrodialysis regeneration device 6 through the pump 9.

[0134] (3) Turn on the power switch of the electrodialysis regeneration device 6 to perform electrodialysis. The preliminarily purified carbon dioxide absorbent flows out from the top of the electrodialysis regeneration device 6 through the valve 4.

[0135] (4) Close valves 2 and 4, and open valves 3 and 5. At this time, the pre-purified carbon dioxide absorbent enters from the top of the electrodialysis regeneration device 6 through pump 8 and valve 3, and continues to run electrodialysis. The regenerated carbon dioxide absorbent flows out from the bottom of the electrodialysis regeneration device 6 through valve 5.

[0136] The power supply voltage of the electrodialysis regeneration device 6 is set to 0.5–15V.

[0137] The alkaline solution prepared in the concentrated waste liquid tank 7 is one of KOH solution, K2CO3 solution and KHCO3 solution or any combination thereof, and the concentration of the alkaline solution is 0.1 to 1 mol / L.

[0138] The carbon dioxide absorbent regeneration methods in Examples 1-8 also include the recovery of heat-stable salts:

[0139] The waste liquid in the concentrate chamber waste liquid tank 7 is treated using an evaporator crystallizer. The liquid is evaporated and crystallized at 100-120℃ for 60-240 minutes. After cooling, a heat-stable salt and an aqueous phase are obtained. KOH is added to the aqueous phase, and the liquid is then returned to the concentrate chamber waste liquid tank 7 for reuse.

[0140] The evaporator crystallizer is a DTB type evaporator, a forced circulation type evaporator, or an Oslo type evaporator.

[0141] Furthermore, in Examples 1-8, the heat-stable salt removal rate of Examples 1-2 and Examples 4-8 is 97% to 99.7%, and the heat-stable salt removal rate is even higher; the power supply voltage of the electrodialysis regeneration device 6 is preferably set to 3 to 15V.

Claims

1. A carbon dioxide absorbent regeneration system, characterized in that, include: The system comprises a filter (1), a valve (2), a valve (3), a valve (4), a valve (5), an electrodialysis regeneration device (6), a concentrate chamber waste liquid vessel (7), a pump (8), and a pump (9); wherein one end of the pump (8) is connected to the filter (1), the other end of the pump (8) is connected to the valve (2) and the valve (3), the valve (2) is connected to the bottom of the electrodialysis regeneration device (6), the valve (3) is connected to the top of the electrodialysis regeneration device (6), the valve (4) is connected to the top of the electrodialysis regeneration device (6), the valve (5) is connected to the bottom of the electrodialysis regeneration device (6), one end of the pump (9) is connected to the concentrate chamber waste liquid vessel (7), and the other end of the pump (9) is connected to the bottom of the electrodialysis regeneration device (6).

2. The carbon dioxide absorbent regeneration system according to claim 1, characterized in that, The filter (1) is a Y-type filter.

3. A method for regenerating carbon dioxide absorbent, characterized in that, Operating in the system of claim 1, the carbon dioxide absorbent regeneration method comprises: (1) Open valves (2) and (4), close valves (3) and (5), and turn on pump (8). At this time, the carbon dioxide absorbent to be regenerated, which has been filtered and purified by the filter, flows into the bottom of the electrodialysis regeneration device (6) through pump (8) and valve (2). (2) Prepare an alkaline solution in the concentrated waste liquid tank (7), turn on the pump (9), and the alkaline solution in the concentrated waste liquid tank (7) flows into the bottom of the electrodialysis regeneration device (6) through the pump (9); (3) Turn on the power switch of the electrodialysis regeneration device (6) to perform electrodialysis. The preliminarily purified carbon dioxide absorbent flows out from the top of the electrodialysis regeneration device (6) through the valve (4). (4) Close valves (2) and (4), and open valves (3) and (5). At this time, the preliminarily purified carbon dioxide absorbent enters from the top of the electrodialysis regeneration device (6) through pump (8) and valve (3) and continues to run electrodialysis. The regenerated carbon dioxide absorbent flows out from the bottom of the electrodialysis regeneration device (6) through valve (5).

4. The carbon dioxide absorbent regeneration method according to claim 3, characterized in that, The power supply voltage of the electrodialysis regeneration device (6) is set to 0.5-15V.

5. The carbon dioxide absorbent regeneration method according to claim 3, characterized in that, The power supply voltage of the electrodialysis regeneration device (6) is set to 3-15V.

6. The carbon dioxide absorbent regeneration method according to claim 3, characterized in that, The concentration of the alkaline solution prepared in the concentrated waste liquid tank (7) is 0.1 to 1 mol / L.

7. The carbon dioxide absorbent regeneration method according to claim 6, characterized in that, The alkaline solution is one of KOH solution, K2CO3 solution and KHCO3 solution or any combination thereof.

8. The carbon dioxide absorbent regeneration method according to claim 3, characterized in that, The carbon dioxide absorbent regeneration method also includes the recovery of heat-stable salts: the waste liquid in the concentrate chamber waste liquid vessel (7) is treated by using an evaporator crystallizer, and evaporated and crystallized at 100-120°C for 60-240 min. After cooling, heat-stable salts and an aqueous phase are obtained. After adding KOH to the aqueous phase, it is returned to the concentrate chamber waste liquid vessel (7) for continued use.

9. The carbon dioxide absorbent regeneration method according to claim 8, characterized in that, The evaporator crystallizer is a DTB type evaporator, a forced circulation type evaporator, or an Oslo type evaporator.

10. The application of the carbon dioxide absorbent regeneration method according to any one of claims 3-9 in carbon dioxide capture, utilization and storage technology.

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