CN216755997U - System for get rid of heat stable salt in industry carbon dioxide capture system - Google Patents

Abstract

The utility model relates to a system for removing heat stable salt in an industrial carbon dioxide capture system. The utility modelNovel process comprising CO₂Recovery system, its structural feature lies in: also included is a heat stable salt removal system, CO₂The recovery system is connected with the heat stable salt removing system, and the heat stable salt removing system comprises an ultrafiltration unit, an electrodialysis device, a concentrated solution storage tank, an alkali storage tank, a third pump, a fourth pump, a fifth pump, a sixth pump, a first valve and a second valve, wherein the third pump and the CO are connected₂The recovery system is connected, the ultrafiltration unit is connected with the third pump, the first valve is connected with the ultrafiltration unit, the electrodialysis device is connected with the first valve, the fourth pump is connected with the electrodialysis device, and CO₂The recovery system is connected with the fourth pump, the fifth pump is connected with the first valve, the concentrated solution storage tank is connected with the fifth pump, the sixth pump is connected with the concentrated solution storage tank, the alkali storage tank is connected with the sixth pump, and the second valve is connected with the electrodialysis device and the concentrated solution storage tank.

Description

System for get rid of heat stable salt in industry carbon dioxide capture system

Technical Field

The utility model relates to a system for removing heat stable salt in an industrial carbon dioxide capture system.

Background

In recent years, carbon dioxide (CO) has been generated by the combustion of fossil fuels₂) The global warming problem is getting worse and worse due to the caused greenhouse effect. 1800 to 2018 years of atmospheric CO₂The concentration of the nitrogen is increased from 0.28 percent to 0.4 percent, and the temperature of the earth is also increased by nearly 1.5 percent^oC, the corresponding negative effects are not negligible. Reduction of emissions has become an international issue for global environmental conservation. Although the climate change rule 2014-plus 2020 is overruled in China, the emission is reduced by 48.4 percent compared with that of 2005, which is not enough to reach the sustainable development target, so that the CO is further controlled₂And (4) discharging.

Driven by such background, the carbon capture, utilization and sequestration (CCSU) technology gradually draws the key attention of the fossil energy industry, and various CO₂Absorbents are also widely reported. Among them, amine liquid compounds are widely used due to their superior carbon absorption effect, and the most common alcohol amine liquids include Monoethanolamine (MEA), Diethanolamine (DEA), and Methyldiethanolamine (MDEA).

The alcohol amine liquid and CO in the combustion waste gas in the absorption tower₂Contact and absorb, thereby achieving the gas evolution effect. And then, the carbon dioxide is desorbed in the regeneration tower through the heating process to be absorbed, and simultaneously, the alcohol amine liquid is regenerated and recycled to the absorption tower for repeated use.

Into the CO₂Before the recovery system, the waste gas is subjected to a desulfurization and denitrification process, however, the waste gas still passes throughResidual sulfur oxides (SOx) and nitrogen oxides (NOx), which react with oxygen and degrade the amine, form Heat Stable Salts (HSS) that cannot be separated from the alcohol amine liquid in a regeneration column by conventional procedures and therefore accumulate in the alcohol amine liquid, and when its concentration in the amine liquid is higher than 2%, it causes multiple problems, the most serious of which is a decrease in the ability to absorb sulfur and carbon gases without reaching emission standards and corrosion of equipment, and, as stated above, must be removed for the normal operation and extended life of the system.

At present, the technologies capable of effectively removing the heat stable salt include a distillation method, an ion exchange resin method, a membrane separation method and an electrodialysis separation method, wherein the distillation method needs to add alkali to pretreat amine liquid, and the distillation energy consumption is higher; the method of adsorbing thermostable salt ions by ion exchange resin requires resin regeneration operation to achieve the effect of recycling, but a large amount of chemical agents are required in the process, a large amount of recovery liquid and cleaning waste liquid are generated, and the burden is caused to the environment; the Electrodialysis (ED) process in the membrane technology can achieve the effect of heat stable salt separation without consuming any chemical agent, however, protonated alcohol amine also exists in the purified amine liquid, and passes through the ion exchange membrane under the influence of an electric field, so that the loss of the amine compound is caused, the loss rate is in direct proportion to the running time period of electrodialysis, the result is equal to the loss of part of the amine liquid, and the economic burden is increased; all three methods have disadvantages.

Distillation separates the amine liquid and the heat stable salt by thermal distillation. Distillation requires heating of the amine liquid to achieve evaporation, with a relatively high energy consumption.

The ion exchange resin is used for adsorbing heat stable salt by utilizing an adsorption principle, and then the purification of amine liquid is achieved. The resin can be recycled, but requires a large amount of sodium hydroxide for recovery, and also has a large amount of cleaning solution. Ion exchange resins can generate large amounts of cleaning waste, increasing the discharge burden.

The electrodialysis process utilizes the effect that under the action of an electric field, anions and cations respectively move towards an anode and a cathode to achieve the separation effect, and partial amine liquid can be protonated to form part of the heat-stable salt ions in MDEA feed liquidMDEAH⁺Under the influence of the electric field force, the water passes through the cation exchange membrane and migrates to the concentration chamber, so that the MDEA is lost. Electrodialysis Process partially protonated amine MDEAH⁺Will permeate the ion exchange membrane and cause losses.

The CN207276521 patent technology directly utilizes alkali to reduce protonated amine liquid, although the loss rate of concentration is not large, the volume loss is not negligible, a large amount of volume is lost, and even if the concentration is not reduced, the loss of the polyamine liquid can be calculated according to the volume.

The Removal of heat stable salts from N-methyl pyridine amine water using electrochemical system a pilot-scale stuck doi: 10.5004/dwt.2020.25935 in-line alkali addition is used to neutralize the protonated amine with the same effect, although it is good, that the alkali addition, i.e. sodium hydroxide (NaOH), brings the system with the external sodium ion Na⁺ 。

Reference documents: factor analysis and improvement measures of amine liquid loss in the electrodialysis desalination process.

And removing the heat-heat stable salt-fixing salt in the decarburized organic amine by a bipolar membrane electrodialysis method.

SUMMERY OF THE UTILITY MODEL

The present invention is directed to overcoming the above-mentioned deficiencies in the prior art and providing a system for removing thermally stable salts in an industrial carbon dioxide capture system that is structurally designed to be reasonable.

The technical scheme adopted by the utility model for solving the problems is as follows: the system for removing heat stable salt in industrial carbon dioxide capture system comprises CO₂Recovery system, its structural feature lies in: further comprising a heat stable salt removal system, the CO₂The recovery system is connected with a heat-stable salt removing system, the heat-stable salt removing system comprises an ultrafiltration unit, an electrodialysis device, a concentrated solution storage tank, an alkali storage tank, a third pump, a fourth pump, a fifth pump, a sixth pump, a first valve and a second valve, and the third pump and the CO are connected₂The recovery system is connected, ultrafiltration unit and No. three pumps are connected, a valve is connected with ultrafiltration unit, electrodialysis device and a valve are connected, No. four pumps are connected with electrodialysis device, CO₂Recovery system is connected with No. four pumps, No. five pumps are connected with a valve, the concentrate holding vessel is connected with No. five pumps, No. six pumps are connected with the concentrate holding vessel, the alkali holding vessel is connected with No. six pumps, No. two valves are connected with electrodialysis device and concentrate holding vessel.

Further, the CO is₂Recovery system includes absorption tower, regenerator column, amine liquid holding vessel, condenser, heat exchanger, No. one heat exchanger, No. two heat exchangers, No. three heat exchangers, No. four heat exchangers, a pump and No. two pumps, the absorption tower is connected with a pump, a pump is connected with a heat exchanger, a heat exchanger is connected with the amine liquid holding vessel, amine liquid holding vessel is connected with No. four heat exchangers, No. four heat exchangers are connected with the absorption tower, the regenerator column is connected with No. three heat exchangers, No. three heat exchangers are connected with No. two pumps, No. two pumps are connected with a heat exchanger, a heat exchanger is connected with the regenerator column, the regenerator column is connected with No. two heat exchangers, No. two heat exchangers are connected with the condenser, the condenser is connected with the regenerator column.

Furthermore, the third pump is connected with an amine liquid storage tank, and the amine liquid storage tank is connected with the fourth pump.

Further, the third pump is connected with CO₂Recovery system passes through eighteen flow path connections, ultrafiltration unit passes through nineteen flow path connections with No. three pumps, a valve passes through twenty flow path connections with ultrafiltration unit, electrodialysis device is connected with a valve, No. four pumps pass through twenty-eight flow path connections with electrodialysis device, CO₂Recovery system passes through twenty-ninth runner with No. four pumps and is connected, No. five pumps pass through twenty-first runner with a valve and are connected, concentrate holding vessel passes through twenty-two runners (22) with No. five pumps and is connected, No. six pumps pass through twenty-three runner with the concentrate holding vessel and are connected, alkali holding vessel passes through twenty-four runner with No. six pumps and is connected, No. two valves and electrodialysis device and concentrate holding vessel are respectively through twenty-seven runner and twenty-five runner connection, No. two valves and twenty-six runnerAnd connecting the flow passages.

Furthermore, the absorption tower is connected with a first flow channel and a second flow channel, the absorption tower is connected with a first pump through a fourth flow channel, the first pump is connected with a first heat exchanger through a fifth flow channel, the first heat exchanger is connected with an amine liquid storage tank through a sixth flow channel, the amine liquid storage tank is connected with a third flow channel, the amine liquid storage tank is connected with a fourth heat exchanger through a seventh flow channel, the fourth heat exchanger is connected with the absorption tower through an eighth flow channel, the regeneration tower is connected with a third heat exchanger through an eleventh flow channel and a twelfth flow channel, the third heat exchanger is connected with a second pump through a tenth flow channel, the second pump is connected with the first heat exchanger through a fourteenth flow channel, the first heat exchanger is connected with the regeneration tower through a ninth flow channel, and the regeneration tower is connected with the second heat exchanger through a fifteenth flow channel, the second heat exchanger is connected with the condenser through a sixteen-channel, the condenser is connected with a seventeen-channel, and the condenser is connected with the regeneration tower through a thirteen-channel.

Furthermore, the first valve and the second valve are both multi-channel valves.

Compared with the prior art, the utility model has the following advantages: CO removal using electrodialysis principles₂The heat stable salt accumulated in the system is captured, the original concentrated solution is subjected to secondary treatment to achieve the aim of minimizing amine liquid loss, the first stage process is an electrodialysis desalination unit to separate the heat stable salt from the amine liquid system, the heat stable salt and the amine liquid system comprise a common anion removal unit and a special anion removal unit, the second stage process is to recover the amine compound in the first batch of waste liquid, and the electrodialysis device can be operated to reduce the operation space and the cost.

Can effectively remove CO on the premise of not increasing investment cost significantly₂The most troublesome heat of the recovery system stabilizes salt, and the effect of making the best use of the substances is achieved, the amine liquid is not compromised, the extremely-caused recovery is achieved, and the recovery can be realized.

The amine liquid lost by the traditional electrodialysis process is recycled, the amine liquid is also a liquid polluting the nature, can be recycled in the concentrated solution and is not discharged after being recycled, so that the method is environment-friendly and low in cost, and a larger alkali storage tank and a larger concentrated solution storage tank are not needed.

The concept of concentrating the primary concentrated solution again is firstly put forward to achieve ultimate recovery, the loss of the amine solution is minimized, the amine solution is more effectively recovered, and the amine solution with certain additional danger is avoided being treated.

Drawings

FIG. 1 is a schematic diagram of a system for removing thermally stable salts in an industrial carbon dioxide capture system according to an embodiment of the present invention.

In the figure: CO 2₂A recovery system 99, a thermally stable salt removal system 100,

An absorption tower 1, a regeneration tower 2, an amine liquid storage tank 3, a condenser 4, an ultrafiltration unit 5, an electrodialysis device 6, a concentrated solution storage tank 7, an alkali storage tank 8,

A first pump 61, a second pump 62, a third pump 63, a fourth pump 64, a fifth pump 65, a sixth pump 66,

First heat exchanger 71, second heat exchanger 72, third heat exchanger 73, fourth heat exchanger 74,

First channel 81, second channel 82, third channel 83, fourth channel 84, fifth channel 85, sixth channel 86, seventh channel 87, eighth channel 88, ninth channel 89, tenth channel 810, eleventh channel 811, twelfth channel 812, thirteenth channel 813, fourteenth channel 814, fifteenth channel 815, sixteenth channel 816, seventeen channel 817, eighteen channel 818, nineteen channel 819, twenty-first channel 820, twenty-first channel 821, twenty-second channel 822, twenty-third channel 823, twenty-fourth channel 824, twenty-fifth channel 825, twenty-sixth channel 826, twenty-seventh channel 827, twenty-eighth channel 828, twenty-ninth channel 829,

A first valve 91 and a second valve 92.

Detailed Description

The present invention will be described in further detail below by way of examples with reference to the accompanying drawings, which are illustrative of the present invention and are not to be construed as limiting the present invention.

Examples are given.

Referring to fig. 1, it should be understood that the structures, ratios, sizes, and the like shown in the drawings are only used for understanding and reading the disclosure, and are not used for limiting the conditions that the present invention can be implemented, so they have no technical essence, and any structural modifications, ratio changes or size adjustments should fall within the scope of the present invention without affecting the function and the achievable purpose of the present invention. In the present specification, the terms "upper", "lower", "left", "right", "middle" and "one" are used for clarity of description, and are not used to limit the scope of the present invention, and the relative relationship between the terms and the relative positions may be changed or adjusted without substantial technical changes.

The system for removing heat stable salt in the industrial carbon dioxide capture system in the embodiment comprises CO₂Recovery system 99 and thermally stable salt removal system 100, CO₂The recovery system 99 is connected to a thermally stable salt removal system 100.

The thermostable salt removal system 100 in this embodiment includes an ultrafiltration unit 5, an electrodialysis device 6, a concentrate storage tank 7, an alkali storage tank 8, a third pump 63, a fourth pump 64, a fifth pump 65, a sixth pump 66, a first valve 91, and a second valve 92, the third pump 63, and CO₂The recovery system 99 is connected, the ultrafiltration unit 5 is connected with the third pump 63, the first valve 91 is connected with the ultrafiltration unit 5, the electrodialysis device 6 is connected with the first valve 91, the fourth pump 64 is connected with the electrodialysis device 6, and CO is introduced into the system₂The recovery system 99 is connected with No. four pump 64, and No. five pump 65 are connected with valve 91, and concentrate holding vessel 7 is connected with No. five pump 65, and No. six pump 66 is connected with concentrate holding vessel 7, and alkali holding vessel 8 is connected with No. six pump 66, and No. two valve 92 is connected with electrodialysis device 6 and concentrate holding vessel 7, and No. one valve 91 and No. two valve 92 are multichannel valves.

CO in this example₂The recovery system 99 comprises an absorption column 1 and a recovery towerRaw tower 2, amine liquid storage tank 3, condenser 4, heat exchanger 71, heat exchanger 72, heat exchanger 73, heat exchanger 74, pump 61 and pump 62, the absorption tower 1 is connected with a first pump 61, the first pump 61 is connected with a first heat exchanger 71, the first heat exchanger 71 is connected with an amine liquid storage tank 3, the amine liquid storage tank 3 is connected with a fourth heat exchanger 74, the fourth heat exchanger 74 is connected with the absorption tower 1, the regeneration tower 2 is connected with a third heat exchanger 73, the third heat exchanger 73 is connected with a second pump 62, the second pump 62 is connected with the first heat exchanger 71, the first heat exchanger 71 is connected with the regeneration tower 2, the regeneration tower 2 is connected with the second heat exchanger 72, the second heat exchanger 72 is connected with a condenser 4, the condenser 4 is connected with the regeneration tower 2, the third pump 63 is connected with the amine liquid storage tank 3, and the amine liquid storage tank 3 is connected with a fourth pump 64.

Normally, the third pump 63 is connected to CO₂The recovery system 99 is connected through eighteen flow channels 818, the ultrafiltration unit 5 is connected with the third pump 63 through a nineteen flow channel 819, the first valve 91 is connected with the ultrafiltration unit 5 through a twentieth flow channel 820, the electrodialysis device 6 is connected with the first valve 91, the fourth pump 64 is connected with the electrodialysis device 6 through a twenty-eight flow channel 828, and CO is discharged from the first pump and the second pump₂The recovery system 99 is connected with the fourth pump 64 through a twenty-ninth flow channel 829, the fifth pump 65 is connected with the first valve 91 through a twenty-first flow channel 821, the concentrated solution storage tank 7 is connected with the fifth pump 65 through a twenty-second flow channel 822, the sixth pump 66 is connected with the concentrated solution storage tank 7 through a twenty-third flow channel 823, the alkali storage tank 8 is connected with the sixth pump 66 through a twenty-fourth flow channel 824, the second valve 92 is connected with the electrodialysis device 6 and the concentrated solution storage tank 7 through a twenty-seventh flow channel 827 and a twenty-fifth flow channel 825, and the second valve 92 is connected with a twenty-sixth flow channel 826.

In general, the absorption tower 1 is connected with a first flow passage 81 and a second flow passage 82, the absorption tower 1 is connected with a first pump 61 through a fourth flow passage 84, the first pump 61 is connected with a first heat exchanger 71 through a fifth flow passage 85, the first heat exchanger 71 is connected with an amine liquid storage tank 3 through a sixth flow passage 86, the amine liquid storage tank 3 is connected with a third flow passage 83, the amine liquid storage tank 3 is connected with a fourth heat exchanger 74 through a seventh flow passage 87, the fourth heat exchanger 74 is connected with the absorption tower 1 through an eighth flow passage 88, the regeneration tower 2 is connected with a third heat exchanger 73 through an eleventh flow passage 811 and a twelfth flow passage 812, the third heat exchanger 73 is connected with a second pump 62 through a tenth flow passage 810, the second pump 62 is connected with the first heat exchanger 71 through a fourteenth flow passage 814, the first heat exchanger 71 is connected with the regeneration tower 2 through a ninth flow passage 89, the regeneration tower 2 is connected with the second heat exchanger 72 through a fifteenth flow passage 815, the second heat exchanger 72 is connected to the condenser 4 through a sixteen flow passage 816, the condenser 4 is connected to a seventeen flow passage 817, and the condenser 4 is connected to the regeneration tower 2 through a thirteenth flow passage 813.

The working method of the system for removing the heat-stable salt in the industrial carbon dioxide capture system in the embodiment comprises the following steps:

containing CO₂When the gas enters the lower part of the absorption tower 1 from the first flow passage 81, the gas contains CO₂CO in gas₂The ammonia liquid is absorbed by the amine liquid flowing out from the eighth flow passage 88, the purified gas is discharged from the second flow passage 82 at the top of the absorption tower 1, and the rich liquid reaches the first pump 61 through the fourth flow passage 84, and then is heated by the first heat exchanger 71 through the fifth flow passage 85, and reaches the regeneration tower 2.

The third heat exchanger 73 heats the eleventh flow passage 811 to generate steam, and CO of the amine liquid is released from the twelfth flow passage 812₂The gas is fed into the regeneration tower 2 through the twelfth flow passage 812, and the gas in the twelfth flow passage 812 heats the rich liquid in the fifth flow passage 85 again and releases CO₂Releasing CO₂The amine solution becomes poor solution and absorbs CO again₂。

The rich liquid in the fifth flow path 85 is preheated by heating in the tenth flow path 810 and passing the purified amine liquid through the second pump 62 to the first heat exchanger 71, the heat of the amine liquid in the tenth flow path 810 is recovered, and then the poor liquid is transported to the amine liquid storage tank 3 through the sixth flow path 86.

Part of the amine liquid in the amine liquid storage tank 3 reaches the fourth heat exchanger 74 through the seventh flow passage 87, and after cooling, reaches the top of the absorption tower 1 through the eighth flow passage 88 to be subjected to CO again₂Absorbing and realizing the circulation of amine liquid.

When CO is present₂The heat stable salt in the 99 amine liquid absorbent of the recovery system exceeds a certain rangeThe heat stable salt removal system 100 is started, part of the amine liquid passes through the eighteen flow channel 818 to the third pump 63, the discharged amine liquid is transported to the ultrafiltration unit 5 through the nineteen flow channel 819, and the ultrafiltration unit 5 can effectively remove insoluble particles, floating grease and other substances which can affect the electrodialysis operation, such as organic matter blockage of an electrodialysis membrane stack, so that the service life of an ion exchange membrane is greatly shortened, and the amine liquid is removed;

the amine liquid filtered by the ultrafiltration unit 5 reaches the first valve 91 from the twenty-first flow channel 820 to enter the electrodialysis device 6 for desalination, the heat stable salt and the amine liquid are separated in the desalination process, the treated amine liquid reaches the fourth pump 64 through the twenty-eighth flow channel 828, and returns to the amine liquid storage tank 3 from the twenty-ninth flow channel 829.

The separated heat stable salt reaches a concentrated solution storage tank 7 through a twenty-seventh flow passage 827, the concentrated solution in the concentrated solution storage tank 7 also contains amine compounds transferred by protonation, so that the amine compounds need to be added with alkali to recover the protonated amine, the alkali storage tank 8 enters a sixth pump 66 through a twenty-fourth flow passage 824, the concentrated solution reaches the concentrated solution storage tank 7 through a twenty-thirteen flow passage 823, a stirring system is arranged in the concentrated solution storage tank 7 for uniform mixing, then the concentrated solution reaches an electrodialysis device 6 through a twenty-first flow passage 821 through a twenty-twelfth flow passage 822 to a fifth pump 65 to recover the amine solution, the amine solution is separated into desalted solution again through the electrodialysis device 6, the amine solution enters an amine solution storage tank 3 and is discharged through a second valve 92 to a twenty-sixth flow passage 826.

Specifically, CO₂The recovery system works according to the following principle:

when containing CO₂When the gas enters the lower part of the absorption tower 1 from the first flow passage 81, the gas contains CO₂CO in gas₂The amine liquid is absorbed from the eighth flow path 88, the purified gas is discharged from the second flow path 82 at the top of the absorption tower 1, and the saturated amine liquid (rich liquid) reaches the first pump 61 through the fourth flow path 84, and then is heated by the first heat exchanger 71 through the fifth flow path 85, and reaches the regeneration tower 2.

Heat exchanger No. three 73 heats channel No. eleven 811 to generate steam, and during this process, a very small portion of the amine liquid is released from channel No. twelve 812Divided CO₂The gas is fed into the regeneration tower 2 through the twelfth flow path 812, and the gas in the twelfth flow path 812 heats the rich liquid in the fifth flow path 85 again, releases carbon dioxide, and releases CO₂The amine liquid becomes poor liquid which can absorb CO again₂。

The heat of the amine liquid in the tenth flow path 810 is recovered by heating the amine liquid in the tenth flow path 810, and the purified amine liquid is passed through the second pump 62 to the first heat exchanger 71 to preheat the rich liquid in the fifth flow path 85, and then the poor liquid is transported to the amine liquid storage tank 3 through the sixth flow path 86.

Then, a part of the amine liquid in the amine liquid storage tank 3 reaches the fourth heat exchanger 74 through the seventh flow path 87, and after cooling, reaches the top of the absorption tower 1 through the eighth flow path 88 to be subjected to CO again₂Absorption, thus achieving one circulation of the amine liquid.

Specifically, the thermally stable salt removal system 100 operates as follows:

when CO is present₂When the heat stable salt in the amine liquid absorbent of the recovery system 99 exceeds a certain range, the heat stable salt removal system 100 is started, part of the amine liquid passes through an eighteen-type flow channel 818 to a third-type pump 63, the discharged amine liquid is transported to the ultrafiltration unit 5 through a nineteen-type flow channel 819, and the ultrafiltration unit 5 can effectively remove insoluble particles, floating grease and other substances which can affect the electrodialysis operation, such as organic matter blockage of an electrodialysis membrane stack, so that the service life of an ion exchange membrane is greatly shortened, and the substances are removed; the amine liquid filtered by the ultrafiltration unit 5 reaches the first valve 91 from the No. twenty flow channel 820 to enter the electrodialysis device 6 for desalination, the heat stable salt and the amine liquid are separated in the process, the treated amine liquid reaches the No. four pump 64 through the twenty-eight flow channel 828, and returns to the amine liquid storage tank 3 from the twenty-nine flow channel 829.

On the other hand, the separated thermostable salt reaches the concentrated solution storage tank 7 through the twenty-seventh flow passage 827, the concentrated solution also contains amine compounds transferred by protonation, so that the protonated amine needs to be recovered by adding alkali, the alkali storage tank 8 enters the sixth pump 66 through the twenty-fourth flow passage 824, reaches the concentrated solution storage tank 7 through the twenty-thirteen flow passage 823, the concentrated solution storage tank 7 is uniformly mixed by a stirring system, and then reaches the electrodialysis device 6 through the twenty-first flow passage 821 by the twenty-twelfth flow passage 822 to the fifth pump 65 to recover the amine solution, and is separated into desalted solution again through the electrodialysis device 6, namely, the amine solution enters the amine solution storage tank 3, and the concentrated solution is almost free of amine compounds and is discharged through the second valve 92 to the twenty-sixth flow passage 826.

Specifically, the electrodialysis operation principle is as follows:

cations are migrated to the cathode side by the electric field force, anions are migrated to the anode by the electric field force, and the cations are blocked or permeable by an anion-cation exchange membrane arranged in the module according to a certain structure in the migration process. When the path on which the anions travel again encounters the anion exchange membrane (C-membrane), the anions are permeable, and when the path on which the anions travel again encounters the cation exchange membrane, the anions are blocked from being permeable.

Because of the special properties and structure, the heat-stable salts in the form of anions and the amines in the form of cations are separated into the so-called concentrated solution, and the other amine solutions are returned to CO again after the adsorption properties are restored₂In the recovery system 99, the concentration of the amine liquid entering the electrodialysis is between 20% and 50% under normal conditions, the content of heat stable salt is more than 2%, after treatment, the concentration of the amine liquid measured by the desalting solution has some loss, the content of the heat stable salt can reach less than 1%, the concentration of the amine in the concentrated solution, the concentration of the heat stable salt and the volume of the liquid can slowly rise, the amine on the concentrated solution side can be basically understood as the amine compound after protonation, the concentration inside the concentrated solution can reach about 10%, and CO after treatment is finished₂The amine solution from the recovery system 99 is then used to treat the concentrate and re-enter the electrodialysis device 6 before the protonated amine is removed with sodium hydroxide.

MDEAH⁺+OH^-←→MDEA+H₂O

Therefore, the amine does not appear in an ionic form any more and cannot be distributed to the concentrated solution by the electrodialysis device 6, the effect of recovering the amine solution can be achieved, the economic burden of the amine solution is greatly reduced, the amine solution is called as secondary amine solution recovery, 99% of the amine solution lost in the first electrodialysis desalination can be effectively recovered, the economic burden can be reduced, and sustainable circulation can be achieved.

In addition, it should be noted that the specific embodiments described in the present specification may be different in the components, the shapes of the components, the names of the components, and the like, and the above description is only an illustration of the structure of the present invention. Equivalent or simple changes in the structure, characteristics and principles of the utility model are included in the protection scope of the patent. Various modifications, additions and substitutions for the specific embodiments described may be made by those skilled in the art without departing from the scope of the utility model as defined in the accompanying claims.

Claims (6)

1. A system for removing heat stable salts from an industrial carbon dioxide capture system comprising CO₂A recovery system (99), characterized by: further comprising a thermally stable salt removal system (100), the CO₂The recovery system (99) is connected with the heat-stable salt removal system (100), the heat-stable salt removal system (100) comprises an ultrafiltration unit (5), an electrodialysis device (6), a concentrated solution storage tank (7), an alkali storage tank (8), a third pump (63), a fourth pump (64), a fifth pump (65), a sixth pump (66), a first valve (91) and a second valve (92), and the third pump (63) is connected with the CO₂Recovery system (99) are connected, ultrafiltration unit (5) are connected with No. three pump (63), valve (91) are connected with ultrafiltration unit (5), electrodialysis device (6) are connected with valve (91), No. four pump (64) are connected with electrodialysis device (6), CO₂Recovery system (99) is connected with No. four pump (64), No. five pump (65) are connected with valve (91), concentrate holding vessel (7) are connected with No. five pump (65), the concentrate holding vesselNo. six pumps (66) are connected with a concentrated solution storage tank (7), an alkali storage tank (8) is connected with the No. six pumps (66), and a No. two valve (92) is connected with an electrodialysis device (6) and the concentrated solution storage tank (7).

2. The system for removing thermostable salt in an industrial carbon dioxide capture system as claimed in claim 1, wherein: the CO is₂The recovery system (99) comprises an absorption tower (1), a regeneration tower (2), an amine liquid storage tank (3), a condenser (4), a first heat exchanger (71), a second heat exchanger (72), a third heat exchanger (73), a fourth heat exchanger (74), a first pump (61) and a second pump (62), wherein the absorption tower (1) is connected with the first pump (61), the first pump (61) is connected with the first heat exchanger (71), the first heat exchanger (71) is connected with the amine liquid storage tank (3), the amine liquid storage tank (3) is connected with the fourth heat exchanger (74), the fourth heat exchanger (74) is connected with the absorption tower (1), the regeneration tower (2) is connected with the third heat exchanger (73), the third heat exchanger (73) is connected with the second pump (62), and the second pump (62) is connected with the first heat exchanger (71), the first heat exchanger (71) is connected with the regeneration tower (2), the regeneration tower (2) is connected with the second heat exchanger (72), the second heat exchanger (72) is connected with the condenser (4), and the condenser (4) is connected with the regeneration tower (2).

3. The system for removing thermostable salt in an industrial carbon dioxide capture system as claimed in claim 2, wherein: the third pump (63) is connected with the amine liquid storage tank (3), and the amine liquid storage tank (3) is connected with the fourth pump (64).

4. The system for removing thermostable salt in an industrial carbon dioxide capture system as claimed in claim 1, wherein: the third pump (63) and CO₂The recovery system (99) is connected with an eighteen-type flow passage (818), and the ultrafiltration unit (5) and the third pump (63) are connected with each other through a nineteen-phase flow passageNo. 819 is connected, the first valve (91) is connected with an ultrafiltration unit (5) through a No. twenty flow channel (820), the electrodialysis device (6) is connected with the first valve (91), the fourth pump (64) is connected with the electrodialysis device (6) through a No. twenty-eight flow channel (828), and the CO is discharged from the first pump and is discharged from the second pump₂The recovery system (99) is connected with a fourth pump (64) through a twenty-ninth flow channel (829), the fifth pump (65) is connected with a first valve (91) through a twenty-first flow channel (821), the concentrated solution storage tank (7) is connected with the fifth pump (65) through a twenty-second flow channel (822), the sixth pump (66) is connected with the concentrated solution storage tank (7) through a twenty-third flow channel (823), the alkali storage tank (8) is connected with the sixth pump (66) through a twenty-fourth flow channel (824), the second valve (92) is connected with the electrodialysis device (6) and the concentrated solution storage tank (7) through a twenty-seventh flow channel (827) and a twenty-fifth flow channel (825), and the second valve (92) is connected with the twenty-sixth flow channel (826).

5. The system for removing thermostable salt in an industrial carbon dioxide capture system as claimed in claim 2, wherein: the absorption tower (1) is connected with a first flow passage (81) and a second flow passage (82), the absorption tower (1) is connected with a first pump (61) through a fourth flow passage (84), the first pump (61) is connected with a first heat exchanger (71) through a fifth flow passage (85), the first heat exchanger (71) is connected with an amine liquid storage tank (3) through a sixth flow passage (86), the amine liquid storage tank (3) is connected with a third flow passage (83), the amine liquid storage tank (3) is connected with a fourth heat exchanger (74) through a seventh flow passage (87), the fourth heat exchanger (74) is connected with the absorption tower (1) through an eighth flow passage (88), the regeneration tower (2) is connected with the third heat exchanger (73) through an eleventh flow passage (811) and a twelfth flow passage (812), the third heat exchanger (73) is connected with the second pump (62) through a tenth flow passage (810), the second pump (62) is connected with the first heat exchanger (71) through a fourteen-channel (814), the first heat exchanger (71) is connected with the regeneration tower (2) through a ninth-channel (89), the regeneration tower (2) is connected with the second heat exchanger (72) through a fifteenth-channel (815), the second heat exchanger (72) is connected with the condenser (4) through a sixteenth-channel (816), the condenser (4) is connected with a seventeen-channel (817), and the condenser (4) is connected with the regeneration tower (2) through a thirteen-channel (813).

6. The system for removing thermostable salt in an industrial carbon dioxide capture system as claimed in claim 1, wherein: the first valve (91) and the second valve (92) are both multi-channel valves.

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