CN117695821A - Carbon trapping system - Google Patents
Carbon trapping system Download PDFInfo
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- CN117695821A CN117695821A CN202311649945.1A CN202311649945A CN117695821A CN 117695821 A CN117695821 A CN 117695821A CN 202311649945 A CN202311649945 A CN 202311649945A CN 117695821 A CN117695821 A CN 117695821A
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- absorbent
- lean
- absorption tower
- inlet
- carbon capture
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 96
- 229910052799 carbon Inorganic materials 0.000 title claims abstract description 70
- 239000007788 liquid Substances 0.000 claims abstract description 137
- 239000002250 absorbent Substances 0.000 claims abstract description 135
- 230000002745 absorbent Effects 0.000 claims abstract description 135
- 238000010521 absorption reaction Methods 0.000 claims abstract description 81
- 230000008929 regeneration Effects 0.000 claims abstract description 60
- 238000011069 regeneration method Methods 0.000 claims abstract description 60
- 238000004821 distillation Methods 0.000 claims abstract description 44
- 238000000909 electrodialysis Methods 0.000 claims abstract description 44
- 238000000108 ultra-filtration Methods 0.000 claims abstract description 42
- 239000000243 solution Substances 0.000 claims abstract description 41
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims abstract description 28
- 239000003546 flue gas Substances 0.000 claims abstract description 28
- 238000000746 purification Methods 0.000 claims abstract description 21
- 239000012267 brine Substances 0.000 claims abstract description 18
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 claims abstract description 18
- 238000010438 heat treatment Methods 0.000 claims description 8
- 150000003839 salts Chemical class 0.000 description 26
- 239000007787 solid Substances 0.000 description 23
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 18
- 239000002245 particle Substances 0.000 description 16
- 150000001412 amines Chemical class 0.000 description 9
- 229910002092 carbon dioxide Inorganic materials 0.000 description 9
- 239000001569 carbon dioxide Substances 0.000 description 9
- 238000003860 storage Methods 0.000 description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 238000003795 desorption Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 238000005516 engineering process Methods 0.000 description 5
- 239000007789 gas Substances 0.000 description 5
- 238000009825 accumulation Methods 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- 238000005265 energy consumption Methods 0.000 description 3
- 239000012535 impurity Substances 0.000 description 3
- 239000013618 particulate matter Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- HZAXFHJVJLSVMW-UHFFFAOYSA-N 2-Aminoethan-1-ol Chemical compound NCCO HZAXFHJVJLSVMW-UHFFFAOYSA-N 0.000 description 2
- 229940058020 2-amino-2-methyl-1-propanol Drugs 0.000 description 2
- BFSVOASYOCHEOV-UHFFFAOYSA-N 2-diethylaminoethanol Chemical compound CCN(CC)CCO BFSVOASYOCHEOV-UHFFFAOYSA-N 0.000 description 2
- 239000004480 active ingredient Substances 0.000 description 2
- CBTVGIZVANVGBH-UHFFFAOYSA-N aminomethyl propanol Chemical compound CC(C)(N)CO CBTVGIZVANVGBH-UHFFFAOYSA-N 0.000 description 2
- 238000010612 desalination reaction Methods 0.000 description 2
- ZBCBWPMODOFKDW-UHFFFAOYSA-N diethanolamine Chemical compound OCCNCCO ZBCBWPMODOFKDW-UHFFFAOYSA-N 0.000 description 2
- 230000005684 electric field Effects 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 230000002779 inactivation Effects 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 239000000049 pigment Substances 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 238000004064 recycling Methods 0.000 description 2
- 238000001179 sorption measurement Methods 0.000 description 2
- -1 alcohol amine Chemical class 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000003014 ion exchange membrane Substances 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 238000010525 oxidative degradation reaction Methods 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000000779 smoke Substances 0.000 description 1
Abstract
The invention relates to the technical field of carbon capture, and discloses a carbon capture system. The carbon trapping system comprises a flue gas carbon trapping unit and an absorbent purifying unit; the flue gas carbon capture unit comprises an absorption tower, a lean-rich liquid heat exchanger, a regeneration tower and a lean liquid cooler; the absorbent purifying unit comprises an ultrafiltration device, an electrodialysis device and a reduced pressure distillation device; the inlet of the ultrafiltration device and the absorbent inlet of the absorption tower are connected with the outlet of the lean liquid cooler; the inlet of the electrodialysis device and the absorbent inlet of the absorption tower are connected with the outlet of the ultrafiltration device; an absorbent outlet of the electrodialysis device is connected with an absorbent inlet of the absorption tower, and a strong brine outlet of the electrodialysis device is connected with an inlet of the reduced pressure distillation device; the outlet of the reduced pressure distillation device is connected with the absorbent inlet of the absorption tower. The carbon trapping system conveys the regenerated lean solution to the absorbent purifying unit for purification, and conveys the purified absorbent to the absorption tower for reuse, so that the stable operation of the whole carbon trapping system is well maintained.
Description
Technical Field
The invention relates to the technical field of carbon capture, in particular to a carbon capture system.
Background
At present, the commonly used carbon trapping technology is a carbon trapping technology by a chemical absorption method, wherein the carbon trapping technology by the chemical absorption method utilizes alcohol amine absorption liquid to absorb CO in flue gas 2 The technology for realizing carbon trapping is the only technology capable of realizing carbon trapping on the scale of hundreds of thousands of tons and above at present. However, under the condition that the absorbent adopted in the existing carbon trapping system continuously runs for a long time, the regenerated absorbent can be aged to different degrees or even irreversibly deactivated due to the accumulation of smoke and dust, oxidative degradation of organic amine and the like, so that the overall running of the carbon trapping system is affected. The purification effect of the absorbent in the existing carbon capture system is difficult to achieve to the expected level, and the activity of the absorbent obtained after purification is reduced, so that the long-time stable and continuous operation of the carbon capture system is not facilitated.
Disclosure of Invention
The invention aims to solve the problems that the carbon trapping system is difficult to maintain stable operation for a long time and the like due to poor purifying effect of an absorbent in the carbon trapping system in the prior art, and provides the carbon trapping system.
In order to achieve the above object, an aspect of the present invention provides a carbon capture system including a flue gas carbon capture unit and an absorbent purification unit;
the flue gas carbon capture unit comprises an absorption tower, a lean-rich liquid heat exchanger, a regeneration tower and a lean liquid cooler;
the rich liquid from the absorption tower is conveyed to the lean-rich liquid heat exchanger and then conveyed to the regeneration tower for regeneration to obtain lean liquid;
the lean solution from the regeneration tower is conveyed to the lean-rich solution heat exchanger to exchange heat with the rich solution from the absorption tower, and the lean solution after heat exchange is conveyed to the lean solution cooler;
the absorbent purifying unit comprises an ultrafiltration device, an electrodialysis device and a reduced pressure distillation device;
the inlet of the ultrafiltration device and the absorbent inlet of the absorption tower are connected with the outlet of the lean liquid cooler;
the inlet of the electrodialysis device and the absorbent inlet of the absorption tower are connected with the outlet of the ultrafiltration device;
the absorbent outlet of the electrodialysis device is connected with the absorbent inlet of the absorption tower, and the strong brine outlet of the electrodialysis device is connected with the inlet of the reduced pressure distillation device;
the outlet of the reduced pressure distillation device is connected with the absorbent inlet of the absorption tower.
Preferably, the flue gas carbon capture unit further comprises a reboiler;
the rich liquid from the regeneration tower is circulated into the reboiler for heating, and then returned to the regeneration tower.
Preferably, the absorbent purification unit further comprises activated carbon means for treating the absorbent from the lean liquor cooler, followed by delivery to the ultrafiltration means.
Preferably, a first switching device is arranged between the ultrafiltration device and the electrodialysis device.
Preferably, a second switching device is arranged between the ultrafiltration device and the absorption tower.
Preferably, the electrodialysis device has an operating voltage of 40-100V.
Preferably, the reduced pressure distillation temperature of the reduced pressure distillation device is 150-180 ℃;
preferably, the reduced pressure distillation pressure of the reduced pressure distillation device is less than or equal to 10kPa.
Preferably, a rich liquid pump is arranged in the absorption tower and the lean and rich liquid heat exchanger and is used for conveying the rich liquid from the absorption tower to the lean and rich liquid heat exchanger.
Preferably, lean liquid pumps are arranged in the lean-rich liquid heat exchanger and the lean liquid cooler and are used for conveying lean liquid from the lean-rich liquid heat exchanger to the lean liquid cooler.
According to the carbon trapping system, the flue gas carbon trapping unit is combined with the absorbent purifying unit, the regenerated absorbent is conveyed to the absorbent purifying unit for purification, the absorbent is purified according to the content of solid particles and heat stability salt in the absorbent, when the content of the solid particles in the absorbent exceeds a threshold value but the content of the heat stability salt does not reach the threshold value yet, the absorbent can be conveyed to the ultrafiltration device for treatment, and the absorbent obtained after treatment can be directly returned to the absorption tower for reuse; when the contents of solid particles and heat-stable salts in the absorbent exceed a certain value, the absorbent can be firstly conveyed into an ultrafiltration device to remove the solid particles, then conveyed into an electrodialysis device to be treated, and an external electric field is utilized to drive the ions of the heat-stable salts to directionally move so as to separate organic amine components from the heat-stable salts in the absorbent and effectively remove the salts in the absorbent; and further, the concentrated brine obtained in the electrodialysis device is distilled under reduced pressure, the organic amine remained in the concentrated brine is further recovered, and the recovered organic amine is returned to the absorption tower for use.
The content of solid particles in the absorbent for carbon capture in the absorption tower after purification can be controlled below 10mg/L, the content of heat stability salt is below 1.0wt%, and the long-acting stable operation of the carbon capture system is realized through the mutual cooperation of the flue gas carbon capture unit and the absorbent purification unit.
Drawings
FIG. 1 is a schematic diagram of a carbon capture system according to the present invention.
Description of the reference numerals
1, a flue gas carbon capture unit; 2 an absorbent purification unit;
11 an absorption tower; 12 lean-rich liquid heat exchanger;
13 a regeneration tower; 14 lean liquid cooler;
15 reboiler; 16 a rich liquid pump;
17 lean liquid pump; 18, induced draft fan;
21 an ultrafiltration device; 22 electrodialysis device;
23 a reduced pressure distillation apparatus; 24 activated carbon device;
25 water tank.
Detailed Description
The following describes specific embodiments of the present invention in detail with reference to the drawings. It should be understood that the detailed description and specific examples, while indicating and illustrating the invention, are not intended to limit the invention.
The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.
In the description of the present application, the term "comprise" and any variations thereof are intended to cover a non-exclusive inclusion, such that one or more other features, integers, steps, operations, elements, components, and/or groups thereof may be present or added.
Furthermore, unless explicitly specified and limited otherwise, the terms "connected," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; either directly or indirectly through intermediaries, or in communication with each other. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art as the case may be.
The carbon capture system of the invention comprises a flue gas carbon capture unit 1 and an absorbent purification unit 2, see e.g. 1 in combination. In the present invention, CO in the flue gas to be treated is absorbed by the amine absorbent in the tower 11 of the flue gas carbon capture unit 1 2 And (5) carrying out absorption treatment and purifying the flue gas to be treated. In addition, the absorbent purifying unit 2 is adopted to purify the lean solution (absorbent) regenerated in the regeneration tower 13 of the flue gas carbon capturing unit 1, the absorbent from the lean solution cooler 14 is treated by the ultrafiltration device 21, the electrodialysis device 22 and the reduced pressure distillation device 23 in the absorbent purifying unit 2, the solid particles and the heat-stable salt in the absorbent are treated, the treated absorbent is conveyed into the absorption tower 11 for recycling, the content of the solid particles and the heat-stable salt in the absorbent is controlled in a reasonable range, and the optimization of the performance of the absorbent is realized, so that the efficient and stable operation of the carbon capturing system is ensured.
In the present invention, the flue gas carbon capturing unit 1 includes an absorption tower 11, a lean-rich liquid heat exchanger 12, a regeneration tower 13, and a lean liquid cooler 14.
In the invention, the absorption tower 11 is used for treating the flue gas to be treated, and CO in the flue gas to be treated is absorbed by amine absorption liquid 2 The rich liquid is absorbed and then transferred to the lean-rich liquid heat exchanger 12 for heat exchange.
In a specific embodiment, the rich liquid outlet of the absorption tower 11 is located at the bottom of the tower.
In a specific embodiment, the amine absorbent in the absorption tower 11 may be one or more of Monoethanolamine (MEA), diethanolamine (DEA), 2-amino-2-methyl-1-propanol (AMP) and N, N-Diethylethanolamine (DEEA), which are common in the art.
In a specific embodiment, an induced draft fan 18 is further disposed in the flue gas carbon capture unit 1, and the induced draft fan 18 is used for conveying the flue gas to be treated into the absorption tower 11 for treatment. Specifically, the induced draft fan 18 may be of a type commonly known in the art.
In the present invention, the lean-rich liquid heat exchanger 12 is configured to exchange heat between the rich liquid from the absorption tower 11 and the lean liquid from the regeneration tower 13, heat the rich liquid by using heat of the lean liquid, and then convey the heated rich liquid to the regeneration tower 13 for regeneration and desorption. In a specific embodiment, the lean-rich liquid heat exchanger 12 is a plate heat exchanger structure or a shell-and-tube heat exchanger structure, and may specifically be a plate heat exchanger or a shell-and-tube heat exchanger which are common in the art. In the present invention, the materials transported in the tube side and the shell side of the lean-rich liquid heat exchanger 12 are not limited, and for example, lean liquid may be transported for the tube side and rich liquid may be transported for the shell side; or the tube side conveys rich liquid, and the shell side conveys lean liquid.
In a preferred embodiment, a rich liquid pump 16 is disposed in the absorption tower 11 and the lean-rich liquid heat exchanger 12, and is used for conveying the rich liquid from the absorption tower 11 to the lean-rich liquid heat exchanger 12 for heat exchange. The rich liquid pump 16 may be a pump commonly used in the art for delivering liquid, for example, a centrifugal pump, a screw pump, or a gear pump commonly used in the art.
In the present invention, the regeneration tower 13 is configured to perform heating desorption regeneration on the rich liquid initially heated in the lean-rich liquid heat exchanger 12 to obtain a lean liquid.
In a preferred embodiment, the carbon capture unit 1 further includes a reboiler 15, where the reboiler 15 is configured to exchange heat a part of the rich liquid from the regeneration tower 13 with steam, heat a part of the rich liquid with steam, and return the heated part of the rich liquid to the regeneration tower 13 to raise the temperature inside the regeneration tower 13, so that the temperature inside the regeneration tower 13 is raised to reach the regeneration temperature of the rich liquid, and promote desorption regeneration of the rich liquid to obtain a lean liquid.
In a specific embodiment, the rich liquid from the regeneration tower 13 is circulated into the reboiler 15 for heating, and then returned to the regeneration tower 13. It will be appreciated that only a portion of the rich liquor from the regeneration column 13 is recycled to the reboiler 15 for heating.
In a preferred embodiment, the regeneration temperature in the regeneration column 13 is 80-120 ℃.
In a preferred embodiment, the flue gas carbon capture unit 1 further includes a carbon dioxide storage tank 19 for storing carbon dioxide gas obtained by desorption of the rich liquid in the regeneration tower 13, and the stored carbon dioxide gas can be transported to a next process for preparing the rest of chemicals, so as to realize recycling of carbon dioxide.
In the present invention, the lean solution from the regeneration tower 13 is sent to the lean-rich solution heat exchanger 12 to exchange heat with the rich solution from the absorption tower 11, and the lean solution after heat exchange is sent to the lean solution cooler 14 to be further cooled.
In a specific embodiment, the lean solution obtained after the thermal desorption regeneration in the regeneration tower 13 still has a higher temperature, and the high-temperature lean solution is conveyed to the lean-rich solution heat exchanger 12 to exchange heat with the rich solution from the absorption tower 11, so that the lean solution is used for heating the rich solution, thereby realizing the utilization of lean solution heat and saving the energy consumption of carbon capture. The rich liquid after heat exchange and temperature rise in the lean-rich liquid heat exchanger 12 is conveyed to the regeneration tower 13 to be further heated for desorption regeneration to obtain lean liquid, and the lean liquid after heat exchange and temperature reduction is conveyed to the lean liquid cooler 14 for temperature reduction treatment.
In a preferred embodiment, a lean liquid pump 17 is disposed in the lean-rich liquid heat exchanger 12 and the lean liquid cooler 14, and is used for conveying the lean liquid after heat exchange in the lean-rich liquid heat exchanger 12 to the lean liquid cooler 14 for treatment. The lean liquid pump 17 may be a liquid transfer pump common in the art, for example, a centrifugal pump, a screw pump, or a gear pump common in the art.
In the present invention, the lean solution cooler 14 is used for cooling the lean solution from the lean-rich solution heat exchanger 12, so that the temperature of the lean solution meets the temperature requirement of the absorbent in the absorption tower 11.
In the present invention, in order to recover the absorption performance of the regenerated absorbent (i.e., the cooled lean solution in the lean solution cooler 14), and avoid the problems of reduced carbon capturing effect caused by reduced activity, the absorbent cooled in the lean solution cooler 14 is sent to the absorbent purifying unit 2 for purification treatment, so as to remove solid particles and soluble heat stable salts in the absorbent, and achieve efficient purification, so that the content of the solid particles in the absorbent sent to the absorbing tower 11 for use can be controlled below 10mg/L, the content of the heat stable salts is below 1.0wt%, and the rapid inactivation of the absorbent caused by the accumulation of impurities is avoided, and the continuous and stable operation of the carbon capturing system is ensured.
In a specific embodiment, a control valve (not shown in fig. 1) is disposed between the lean solution cooler 14 and the absorption tower 11, and is used for controlling the flow rate of the absorbent delivered to the absorption tower 11 by the lean solution cooler 14, and when the content of solid particulate matters and heat-stable salts in the absorbent in the lean solution cooler 14 is low, in order to save carbon capturing energy consumption, a part of the absorbent in the lean solution cooler 14 may be delivered to the absorbent purifying unit 2 for treatment.
In the present invention, the absorbent purifying unit 2 includes an ultrafiltration device 21, an electrodialysis device 22, and a reduced pressure distillation device 23.
In a specific embodiment, the inlet of the ultrafiltration device 21 and the absorbent inlet of the absorption column 11 are both connected to the outlet of the lean liquor cooler 14, and the inlet of the electrodialysis device 22 and the absorbent inlet of the absorption column 11 are both connected to the inlet of the ultrafiltration device 21. In the present invention, the ultrafiltration device 21 is used to remove fine solid particulate impurities from the absorbent. The ultrafiltration device 21 may be an ultrafiltration system commonly known in the art, and the specific structure thereof may be referred to in the art, for example, a tubular ultrafiltration system, and the specific structure thereof will not be described herein.
In a specific embodiment, the electrodialysis device 22 is provided with an absorbent outlet connected to the absorbent inlet of the absorption tower 11 and a strong brine outlet connected to the inlet of the reduced pressure distillation device 23. The electrodialysis device 22 is used for treating materials from the ultrafiltration device 21, driving ions of the heat-stable salt to directionally move through an external electric field, and penetrating through an ion exchange membrane in the electrodialysis system to separate organic amine components from the heat-stable salt, so that salt in the absorbent is effectively removed, and the heat-stable salt in the absorbent is removed.
In a preferred embodiment, the electrodialysis device 22 operates at a voltage of 40-100V. The operating voltage refers to the voltage at which the electrodialysis device 22 is operated.
In a specific embodiment, two materials can be obtained after the treatment of the electrodialysis device 22, one of the two materials is the absorbent after the removal of the heat-stable salt, and the other material can be directly conveyed to the absorption tower 11 for use, and the other material is the strong brine obtained after the desalination, wherein the strong brine also contains a certain content of absorbent active ingredients, and the absorbent active ingredients in the strong brine can be extracted after the treatment, and the absorbent obtained by the extraction can be conveyed to the absorption tower 11 for use as well, so that the loss of the absorbent is further reduced. The absorbent outlet of the electrodialysis device 22 is used for delivering the absorbent subjected to desalination treatment to the absorption tower 11, and the strong brine outlet is used for delivering the strong brine to the reduced pressure distillation device 23.
In the present invention, the reduced pressure distillation apparatus 23 is used for distilling and recovering the effective absorbent component remaining in the strong brine from the electrodialysis apparatus 22, and the recovered absorbent can be returned to the absorption tower 11 for use.
In a specific embodiment, a water tank 25 is further disposed between the electrodialysis device 22 and the reduced pressure distillation device 23, and is configured to store the concentrated brine from the electrodialysis device 22, and after the concentrated brine in the water tank 25 reaches a certain storage amount, the concentrated brine is conveyed to the reduced pressure distillation device 23 for distillation treatment.
In a preferred embodiment, the reduced pressure distillation temperature of the reduced pressure distillation apparatus 23 is 150 to 180 ℃, the reduced pressure distillation pressure is less than or equal to 10kPa, for example, 6 to 8kPa (the reduced pressure distillation pressure is absolute pressure), and the recovery temperature of the reduced pressure distillation apparatus 23 is set in a lower range, so that the thermal degradation of the amine absorbent can be further reduced, the effective recovery rate of the effective component in the absorbent is more than 95%, and the loss of the effective component in the absorbent is avoided. In the present invention, the reduced pressure distillation temperature and reduced pressure distillation pressure of the reduced pressure distillation apparatus 23 are both the temperature and pressure set when the reduced pressure distillation apparatus 23 is operated.
In a specific embodiment, the outlet of the reduced pressure distillation apparatus 23 is connected to the absorbent inlet of the absorption tower 11.
In a preferred embodiment, the absorbent cleaning unit 2 further comprises an activated carbon device 24, wherein the activated carbon device 24 is used for removing large solid particles and accumulated pigments from the absorbent in the lean liquor cooler 14, and then sending the large solid particles and accumulated pigments to the ultrafiltration device 21 for treatment. Specifically, the activated carbon device 24 may be an activated carbon device for removing particulates in a solution, which is commonly known in the art, and the specific structure thereof will not be described herein.
In the invention, according to the different components of the absorbent to be purified, the purification modes of the absorbent are divided into two types, when solid particles in the absorbent exceed a threshold value but the heat stability salt does not reach the threshold value yet, the absorbent can be purified by the ultrafiltration device 21, and the treated absorbent is directly conveyed into the absorption tower 11 for carbon capture; when the solid particulate matter and the heat stable salt content in the absorbent exceeds the threshold value, the absorbent may be purified by the ultrafiltration device 21, the electrodialysis device 22, and the reduced pressure distillation device 23 together. Specifically, the absorbent treated by the ultrafiltration device 21 is sent to the electrodialysis device 22 to be treated, the desalted absorbent obtained by the electrodialysis device 22 is sent to the absorption tower 11 to be utilized, the concentrated brine obtained by the electrodialysis device 22 is sent to the reduced pressure distillation device 23 to be treated, and the obtained absorbent is sent to the absorption tower 11 to be utilized.
In a preferred embodiment, a first switching device is provided between the ultrafiltration device 21 and the electrodialysis device 22 for adjusting the operation of the absorbent purification unit 2.
In a preferred embodiment, a second switching device is provided between the ultrafiltration device 21 and the absorption tower 11 for adjusting the operating mode of the absorbent purification unit 2 together with the first switching device.
In a specific embodiment, when the solid particulate matter in the absorbent exceeds a threshold value but the heat stability salt does not reach the threshold value yet, the first switching device may be selected to be turned off and the second switching device may be selected to be turned on; when the contents of solid particles and heat stable salts in the absorbent exceed the threshold value, the first switching device can be selectively turned on, and the second switching device can be turned off. In particular, the first and second switching devices may be means for regulating the flow of liquid, which are common in the art, for example control valves or electrically operated valves.
In a specific embodiment, a suspended matter detector and a conductivity meter are further disposed between the lean solution cooler 14 and the activated carbon device 24, where the suspended matter detector is used to detect the content of solid particulate matters in the absorbent, and the conductivity meter is used to detect the change of the conductivity of the absorbent, so as to determine the concentration of the heat-stable salt in the absorbent, and by detecting the content of the solid particulate matters and the heat-stable salt in the absorbent delivered to the absorbent purifying unit 2, it is determined in which way to purify the absorbent, i.e. to ensure that the absorbent is treated with low energy consumption, and further ensure long-term stable operation of the carbon capturing system.
The present invention will be described in detail by way of examples, but the scope of the present invention is not limited thereto.
The following embodiments are implemented with a carbon capture system including a flue gas carbon capture unit 1 and an absorbent purification unit 2, referring in conjunction to fig. 1;
the carbon capture unit 1 comprises an absorption tower 11, a lean-rich liquid heat exchanger 12, a regeneration tower 13, a lean liquid cooler 14, a reboiler 15, a rich liquid pump 16, a lean liquid pump 17, an induced draft fan 18 and a carbon dioxide storage tank 19;
the absorbent purifying unit 2 comprises an ultrafiltration device 21, an electrodialysis device 22, a reduced pressure distillation device 23, an activated carbon device 24 and a water tank 25;
an outlet of the induced draft fan 18 is connected with a flue gas inlet of the absorption tower 11, a rich liquid outlet of the absorption tower 11 is connected with an inlet of the rich liquid pump 16, and an outlet of the rich liquid pump 16 is connected with a rich liquid inlet of the lean rich liquid heat exchanger 12; a rich liquor outlet of the lean rich liquor heat exchanger 12 is connected with a first rich liquor inlet of the regeneration tower 13, and a rich liquor outlet of the regeneration tower 13 is connected with a rich liquor inlet of the reboiler 15; the rich liquid outlet of the reboiler 15 is connected with the second rich liquid inlet of the regeneration tower 13; a lean liquid outlet of the regeneration tower 13 is connected with a lean liquid inlet of the lean-rich liquid heat exchanger 12; the gas outlet of the regeneration tower 13 is connected with the carbon dioxide storage tank 19; a lean liquid outlet of the lean-rich liquid heat exchanger 12 is connected with an inlet of the lean liquid pump 17, and an outlet of the lean liquid pump 17 is connected with an inlet of the lean liquid cooler 14;
the inlet of the activated carbon device 24 and the absorbent inlet of the absorption tower 11 are connected with the outlet of the lean liquid cooler 14;
the outlet of the activated carbon device 24 is connected with the inlet of the ultrafiltration device 21;
the inlet of the electrodialysis device 22 and the absorbent inlet of the absorption tower 11 are connected with the outlet of the ultrafiltration device 21;
the absorbent outlet of the electrodialysis device 22 is connected with the absorbent inlet of the absorption tower 11, and the strong brine outlet of the electrodialysis device 22 is connected with the inlet of the water tank 25; the outlet of the water tank 25 is connected with the inlet of the reduced pressure distillation apparatus 23;
the outlet of the reduced pressure distillation apparatus 23 is connected to the absorbent inlet of the absorption tower 11;
a first switching device is arranged between the ultrafiltration device 21 and the electrodialysis device 22, and is a control valve;
a second switching device is arranged between the ultrafiltration device 21 and the absorption tower 11, and the switching device is a control valve;
the ultrafiltration device 21 is a tube ultrafiltration.
Example 1
The flue gas to be treated is conveyed into the absorption tower 11 through an induced draft fan 18, is mixed with an absorbent and is subjected to carbon capture, after absorption is finished, rich liquid in the absorption tower 11 is conveyed into the lean-rich liquid heat exchanger 12 through a rich liquid pump 16 to exchange heat, and is conveyed into the regeneration tower 13 to be regenerated to obtain lean liquid, wherein the regeneration temperature in the regeneration tower 13 is 95 ℃; the gas desorbed in the regeneration tower 13 is conveyed to the carbon dioxide storage tank 19 for storage;
part of the rich liquid from the regeneration tower 13 is circulated into the reboiler 15 for heating, and then returned to the regeneration tower 13;
in the lean-rich liquid heat exchanger 12, the lean liquid from the regeneration tower 13 exchanges heat with the rich liquid from the rich liquid pump 16, the rich liquid after heat exchange is conveyed to the regeneration tower 13, and the lean liquid after heat exchange is conveyed to the lean liquid cooler 14 for cooling through the lean liquid pump 17;
when the content of solid particles in the regenerated absorbent exceeds a threshold value, but the content of the heat stability salt does not exceed the threshold value, closing the first switch device, and opening the second switch device; the absorbent from the lean solution cooler 14 is sent to the activated carbon device 24 for adsorption filtration, then sent to the ultrafiltration device 21 for treatment, and the treated absorbent is sent to the absorption tower 11 for utilization, wherein the content of solid particles in the absorbent in the absorption tower 11 after purification is 2.0mg/L.
Example 2
The flue gas to be treated is conveyed into the absorption tower 11 through an induced draft fan 18, is mixed with an absorbent and is subjected to carbon capture, after absorption is finished, rich liquid in the absorption tower 11 is conveyed into the lean-rich liquid heat exchanger 12 through a rich liquid pump 16 to exchange heat, and is conveyed into the regeneration tower 13 to be regenerated to obtain lean liquid, wherein the regeneration temperature in the regeneration tower 13 is 110 ℃; the gas desorbed in the regeneration tower 13 is conveyed to the carbon dioxide storage tank 19 for storage;
part of the rich liquid from the regeneration tower 13 is circulated into the reboiler 15 for heating, and then returned to the regeneration tower 13;
in the lean-rich liquid heat exchanger 12, the lean liquid from the regeneration tower 13 exchanges heat with the rich liquid from the rich liquid pump 16, the rich liquid after heat exchange is conveyed to the regeneration tower 13, and the lean liquid after heat exchange is conveyed to the lean liquid cooler 14 for cooling through the lean liquid pump 17;
when the contents of solid particles and heat-stable salt in the regenerated absorbent exceed the threshold value, the first switching equipment is turned on, and the second switching equipment is turned off; the absorbent from the lean solution cooler 14 is conveyed to the activated carbon device 24 for adsorption filtration, then conveyed to the ultrafiltration device 21 for treatment, the treated absorbent is conveyed to the electrodialysis device 22 for treatment, and the obtained purified absorbent is conveyed to the absorption tower 11 for utilization; the concentrated brine obtained by the electrodialysis device 22 is conveyed to a water tank 25 for storage, then conveyed to the reduced pressure distillation device 23 for treatment, the temperature of reduced pressure distillation is 170 ℃, the pressure of reduced pressure distillation is 2kPa, and the absorbent obtained after treatment is conveyed to the absorption tower 11 for use. The solid particulate matter content in the absorbent in the absorption tower 11 after purification was 1.5mg/L, and the heat-stable salt content was 0.7% by weight.
The carbon capture system can quickly absorb carbon dioxide in the flue gas, can realize deep purification of the regenerated absorbent, avoids quick inactivation of the absorbent caused by accumulation of impurities, ensures the stability of the activity of the absorbent, and simultaneously ensures continuous and stable operation of the carbon capture system
The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.
Claims (10)
1. A carbon capture system, characterized in that the carbon capture system comprises a flue gas carbon capture unit (1) and an absorbent purification unit (2);
the flue gas carbon capture unit (1) comprises an absorption tower (11), a lean-rich liquid heat exchanger (12), a regeneration tower (13) and a lean liquid cooler (14);
the rich liquid from the absorption tower (11) is conveyed to the lean-rich liquid heat exchanger (12) and then conveyed to the regeneration tower (13) for regeneration to obtain lean liquid;
the lean solution from the regeneration tower (13) is conveyed to the lean-rich solution heat exchanger (12) to exchange heat with the rich solution from the absorption tower (11), and the lean solution after heat exchange is conveyed to the lean solution cooler (14);
the absorbent purifying unit (2) comprises an ultrafiltration device (21), an electrodialysis device (22) and a reduced pressure distillation device (23);
the inlet of the ultrafiltration device (21) and the absorbent inlet of the absorption tower (11) are connected with the outlet of the lean liquid cooler (14);
the inlet of the electrodialysis device (22) and the absorbent inlet of the absorption tower (11) are connected with the outlet of the ultrafiltration device (21);
an absorbent outlet of the electrodialysis device (22) is connected with an absorbent inlet of the absorption tower (11), and a strong brine outlet of the electrodialysis device (22) is connected with an inlet of the reduced pressure distillation device (23);
the outlet of the reduced pressure distillation device (23) is connected with the absorbent inlet of the absorption tower (11).
2. The carbon capture system of claim 1, wherein the flue gas carbon capture unit (1) further comprises a reboiler (15);
the rich liquid from the regeneration tower (13) is circulated into the reboiler (15) for heating, and then returned to the regeneration tower (13).
3. The carbon capture system according to claim 1, wherein the absorbent purification unit (2) further comprises an activated carbon device (24) for treating the absorbent from the lean liquor cooler (14) before being fed to the ultrafiltration device (21).
4. The carbon capture system according to claim 1, characterized in that a first switching device is arranged between the ultrafiltration device (21) and the electrodialysis device (22).
5. The carbon capture system according to claim 1, characterized in that a second switching device is provided between the ultrafiltration device (21) and the absorption tower (11).
6. The carbon capture system of claim 1, wherein the electrodialysis device (22) operates at a voltage of 40-100V.
7. The carbon capture system of claim 1, wherein the reduced pressure distillation temperature of the reduced pressure distillation apparatus (23) is 150-180 ℃.
8. The carbon capture system according to claim 1, wherein the reduced pressure distillation pressure of the reduced pressure distillation apparatus (23) is 10kPa or less.
9. The carbon capture system according to claim 1, characterized in that a rich liquid pump (16) is provided in the absorption tower (11) and the lean rich liquid heat exchanger (12) for conveying rich liquid from the absorption tower (11) into the lean rich liquid heat exchanger (12).
10. The carbon capture system according to claim 1, characterized in that a lean liquid pump (17) is arranged in the lean-rich liquid heat exchanger (12) and the lean liquid cooler (14) for conveying lean liquid from the lean-rich liquid heat exchanger (12) into the lean liquid cooler (14).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311649945.1A CN117695821A (en) | 2023-12-04 | 2023-12-04 | Carbon trapping system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311649945.1A CN117695821A (en) | 2023-12-04 | 2023-12-04 | Carbon trapping system |
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| Publication Number | Publication Date |
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| CN117695821A true CN117695821A (en) | 2024-03-15 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202311649945.1A Pending CN117695821A (en) | 2023-12-04 | 2023-12-04 | Carbon trapping system |
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| Country | Link |
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| CN (1) | CN117695821A (en) |
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- 2023-12-04 CN CN202311649945.1A patent/CN117695821A/en active Pending
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