CN111729483A - Carbon dioxide capture system and method - Google Patents

Carbon dioxide capture system and method Download PDF

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Publication number
CN111729483A
CN111729483A CN202010717898.XA CN202010717898A CN111729483A CN 111729483 A CN111729483 A CN 111729483A CN 202010717898 A CN202010717898 A CN 202010717898A CN 111729483 A CN111729483 A CN 111729483A
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China
Prior art keywords
liquid
washing
washing liquid
gas
tower
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CN202010717898.XA
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Chinese (zh)
Inventor
孙路长
王争荣
王桦
王凯亮
吴冲
张丽亚
文潇贤
汪洋
何佳
张士明
陈志荣
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Jiangsu Huadian Jurong Power Generation Co ltd
China Huadian Engineering Group Co Ltd
Huadian Environmental Protection Engineering and Technology Co Ltd
Original Assignee
Jiangsu Huadian Jurong Power Generation Co ltd
China Huadian Engineering Group Co Ltd
Huadian Environmental Protection Engineering and Technology Co Ltd
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Priority to CN202010717898.XA priority Critical patent/CN111729483A/en
Publication of CN111729483A publication Critical patent/CN111729483A/en
Pending legal-status Critical Current

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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D53/00Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34Chemical or biological purification of waste gases
    • B01D53/46Removing components of defined structure
    • B01D53/48Sulfur compounds
    • B01D53/50Sulfur oxides
    • B01D53/501Sulfur oxides by treating the gases with a solution or a suspension of an alkali or earth-alkali or ammonium compound
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D53/00Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34Chemical or biological purification of waste gases
    • B01D53/46Removing components of defined structure
    • B01D53/62Carbon oxides
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D53/00Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34Chemical or biological purification of waste gases
    • B01D53/74General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/77Liquid phase processes
    • B01D53/78Liquid phase processes with gas-liquid contact
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D53/00Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34Chemical or biological purification of waste gases
    • B01D53/96Regeneration, reactivation or recycling of reactants
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2251/00Reactants
    • B01D2251/40Alkaline earth metal or magnesium compounds
    • B01D2251/404Alkaline earth metal or magnesium compounds of calcium
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2251/00Reactants
    • B01D2251/60Inorganic bases or salts
    • B01D2251/604Hydroxides
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2251/00Reactants
    • B01D2251/60Inorganic bases or salts
    • B01D2251/606Carbonates
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2257/00Components to be removed
    • B01D2257/50Carbon oxides
    • B01D2257/504Carbon dioxide
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02ATECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/20Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02CCAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
    • Y02C20/00Capture or disposal of greenhouse gases
    • Y02C20/40Capture or disposal of greenhouse gases of CO2

Abstract

The invention belongs to the technical field of gas capture, and particularly relates to a carbon dioxide capture system and a carbon dioxide capture method. The system comprises a pre-washing tower, a washing liquid recovery device, an absorption tower and a regeneration tower, wherein the washing liquid recovery device is communicated with the pre-washing tower, the washing liquid recovery device comprises a reaction box and a separation box which are communicated, and the reaction box and the separation box are respectively communicated with the pre-washing tower. Be provided with washing liquid recovery unit in this system, can handle the washing liquid, resume the basicity of washing liquid, make its cyclic utilization, the emission of washing liquid has been reduced, the utilization ratio of resource has been improved, can produce calcium-based salt when retrieving the washing liquid, can retrieve as the desulfurizer and recycle, the emission of waste liquid has been reduced, set up washing liquid recovery unit in this system, can realize dual resource recycle, the utilization ratio of resource has been improved, the energy consumption of system has been reduced and the cost of waste liquid treatment has been reduced.

Description

Carbon dioxide capture system and method
Technical Field
The invention belongs to the technical field of gas capture, and particularly relates to a carbon dioxide capture system and a carbon dioxide capture method.
Background
Carbon dioxide is one of the major components of greenhouse gases that contribute to global warming, contributing up to 55% to the greenhouse effect. The carbon dioxide discharged after fossil fuel combustion in a thermal power plant accounts for 30% of the global emission of the same fuel. Thus, the coal fired power plant that emits the most carbon dioxide in the industrial field is the industry with the most potential for carbon dioxide capture. Carbon capture has a variety of technical routes, among which the alcohol amine absorption method is widely used in thermal power generating units.
Because of the coal-fired power plantThe flue gas is generally from a wet desulphurization device or a wet electric precipitation device, and the temperature of the flue gas can reach 50-52 ℃ and exceeds the requirement of the proper inlet temperature of an absorption tower of a carbon capture device. Although ultra-clean emissions have been commonly achieved in power plants, the flue gas also contains small amounts of acid gases, such as SO2、SO3HCl and the like, can influence organic amine on CO in the flue gas2Absorption of (2). Therefore, the flue gas must be pretreated first. The pretreatment device is located in CO2Before the absorption tower, a packed tower is generally used, and acid gas in the flue gas is removed by using alkaline washing liquid, and simultaneously, the smoke temperature is reduced. The conventional prewashing liquid is a low-concentration NaOH solution, and the NaOH solution is stronger in alkalinity except for SO2、SO3Reacting with strong acidic gas such as HCl, and optionally CO2The reaction causes additional consumption of alkali and CO in the flue gas2Is lost. After the circulation operation is carried out for a certain time, the pH value of the pre-washing liquid is reduced, and alkali needs to be supplemented in time. The pre-washing liquid can also be enriched with a large amount of sulfate, sulfite and chloride, and the system needs to be discharged in time so as not to influence the pretreatment effect, which can cause a large amount of waste liquid discharge, and the operation of the waste water treatment facility of the power plant is greatly influenced under the condition that the current power plant requires zero discharge of waste water.
Chinese patent document CN110591769A discloses a blast furnace gas catalytic desulfurization device, which comprises a cooling tower, an absorption tower, a regeneration tower, a first liquid circulation pump 7, a filter 8, a cooling tower 1, a solvent absorbent tank 5, a catalyst tank 9, a heat exchanger 10, a second liquid circulation pump 11, a steam boiler 17, and a second spray device; the solvent absorption tank 5 is communicated with the first solvent tank 4, and the catalyst tank 9 and the first solvent tank 4 are both communicated with a liquid inlet of a first liquid circulating pump 7; a first gas-liquid contact device 2, a first spraying device and a first demisting device 6 are sequentially arranged between the gas inlet and the gas outlet at the top of the absorption tower from bottom to top, the liquid outlet of a second liquid circulating pump 11 is connected with the hydrothermal liquid inlet of a heat exchanger 10, and the hydrothermal liquid outlet of the heat exchanger 10 is connected with the second spraying device. But the cooling tower in the device can generate a large amount of waste liquid, and the resource waste is serious.
Disclosure of Invention
Therefore, the technical problem to be solved by the present invention is to overcome the defects of large wastewater generation amount, serious resource waste, etc. of the pretreatment system of the carbon dioxide capture device in the prior art, thereby providing a carbon dioxide capture system and a method thereof.
Therefore, the invention provides the following technical scheme.
The present invention provides a carbon dioxide capture system comprising,
the pre-washing tower is used for absorbing acid gas in the mixed gas and reducing the temperature of the mixed gas; a washing liquid storage device is arranged at the bottom of the pre-washing tower, and a first washing liquid outlet is formed in the side surface of the washing liquid storage device;
a washing liquid recovery device communicated with the prewashing tower; the washing liquid recovery device comprises a reaction box and a separation box which are communicated, and the reaction box and the separation box are respectively communicated with the prewashing tower;
an absorption tower for absorbing CO in the mixed gas2In communication with the pre-scrubber;
regeneration column for recovery of CO2And is communicated with the absorption tower.
The gas absorbed by the washing liquid in the pre-washing tower is mainly SO2Gas, absorbing a small amount of CO2A gas.
A stirrer is arranged in the reaction box;
a mud scraper is arranged in the separation box, and a slurry outlet is arranged at the bottom of the separation box.
A first packing layer, a first spraying device and a first demisting device are sequentially arranged in the prewashing tower from bottom to top;
the first spraying device is arranged above the washing liquid storage device;
the first washing liquid outlet is communicated with the first spraying device;
the top of the pre-washing tower is provided with a first exhaust port.
And a rich liquid storage device, a second packing layer, a second spraying device, a second demisting device and a second exhaust port are sequentially arranged in the absorption tower from bottom to top.
And a barren solution storage device, a third packing layer, a third spraying device, a third demisting device and a third exhaust port are sequentially arranged in the regeneration tower from bottom to top.
The rich liquid storage device is provided with a rich liquid outlet which is communicated with the third spraying device;
the barren liquor storage device is provided with a barren liquor outlet which is communicated with the second spraying device.
The regeneration tower is also provided with a gas-liquid distribution device, a liquid inlet hole and a liquid outlet hole;
a heater is arranged between the liquid outlet hole and the liquid inlet hole and used for recovering rich liquid;
the gas-liquid distribution device is arranged between the liquid outlet hole and the liquid inlet hole;
the liquid inlet hole is arranged below the third spraying device.
The carbon dioxide capture system also comprises a first heat exchange device, wherein a hot liquid inlet of the first heat exchange device is communicated with the lean liquid outlet, and a hot liquid outlet of the first heat exchange device is communicated with the second spraying device;
and a cold liquid inlet of the first heat exchange device is communicated with the rich liquid outlet, and a cold liquid outlet of the first heat exchange device is communicated with the third spraying device.
The invention also provides a carbon dioxide capturing method, which adopts the carbon dioxide capturing system and comprises the following steps,
washing the mixed gas with a washing solution, and then mixing with CO2The gas absorption solvent is contacted to absorb CO2Absorbing the solvent with gas to form a rich solution;
heating the rich liquid after heat exchange to make CO2Gas is separated out, and the rich solution becomes lean solution;
exchanging heat between lean solution and rich solution, cooling, and mixing with CO2Gas contact to absorb CO2A gas.
The carbon dioxide capturing method further includes a step of recovering and reusing the washing liquid.
The technical scheme of the invention has the following advantages:
1. the invention provides a carbon dioxide capture system which comprises a prewashing tower, a washing liquid recovery device, an absorption tower and a regeneration tower, wherein the washing liquid recovery device is communicated with the prewashing tower, the washing liquid recovery device comprises a reaction box and a separation box which are communicated, and the reaction box and the separation box are respectively communicated with the prewashing tower. Be provided with washing liquid recovery unit in this system, can handle the washing liquid, resume the basicity of washing liquid, make its cyclic utilization, the emission of washing liquid has been reduced, the utilization ratio of resource has been improved, can produce calcium-based salt when retrieving the washing liquid, can retrieve as the desulfurizer and recycle, the emission of waste liquid has been reduced, set up washing liquid recovery unit in this system, can realize dual resource recycle, the utilization ratio of resource has been improved, the energy consumption of system has been reduced and the cost of waste liquid treatment has been reduced.
The washing liquid recovery device has the advantages of small occupied area, small investment and low cost, and the washing liquid can be recycled.
2. According to the carbon dioxide capture system provided by the invention, the stirrer is arranged in the reaction box, so that the recovery rate of the pre-washing liquid can be increased, and the problem of suspended matter sedimentation during the recovery of the pre-washing liquid can be prevented. A mud scraper is arranged in the separation box, which is helpful for separating liquid and solid in the separation box and preventing calcium-based salts from accumulating and scaling at the bottom.
When the washing liquid in the carbon dioxide capture system is recycled, lime milk can be fed into the reaction box by using a lime milk feeding device of a desulfurization wastewater system which is conventionally matched with an electric field, the washing liquid is recycled, lime milk feeding equipment is not required to be additionally added, the cost for treating the washing liquid is reduced, and the effective utilization of resources is realized. The clear liquid at the upper part of the separation tank recovers alkalinity and is sent to a pre-washing tower to circularly absorb acid gas in the mixed gas; the concentrated slurry at the bottom of the separation tank is rich in limestone and is pumped to a wet desulphurization absorption tower of a power plant to be used as SO2And (5) recycling the absorbent.
3. The method for capturing the carbon dioxide is simple and convenient to operate, low in energy consumption and capable of avoiding the problem of discharging a large amount of waste liquid.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 is a schematic view of the configuration of a carbon dioxide capturing system in example 1 of the present invention;
FIG. 2 is a schematic view of the structure of a pre-scrubber according to a second embodiment of example 1 of the present invention;
FIG. 3 is a schematic view of the structure of a preliminary washing column of the third embodiment in example 1 of the present invention;
reference numerals:
1-a prewashing tower; 2-an absorption column; 3-a regeneration tower; 4-a first heat exchange device; 5-a third circulation pump; 6-a fourth circulation pump; 7-a second cooler; 8-a washing liquid recovery device;
1-1-a wash liquor storage device; 1-2-a first packing layer; 1-3-a first spraying device; 1-4-a first defogging device; 1-5-a first exhaust port; 1-6-a first cooler; 1-7-a first circulation pump; 1-8-a first wash liquid outlet; 1-9-a first air inlet; 1-10-pH monitor; 1-11-a first wash liquid inlet; 1-12-a second wash liquid outlet; 1-13-a second wash inlet;
2-1-rich liquid storage device; 2-2-a second packing layer; 2-3-a second spraying device; 2-4-a second demisting device; 2-5-rich liquid outlet; 2-6-a second vent; 2-7-a second air inlet;
3-1-barren liquor storage means; 3-2-gas-liquid distribution device; 3-3-liter air cap; 3-4-a third packing layer; 3-5-a third demisting device; 3-6-a third spraying device; 3-7-liquid outlet holes; 3-8-liquid inlet hole; 3-9-a heater; 3-10-lean solution outlet; 3-11-a third vent;
8-1-reaction box; 8-2-separation tank; 8-3-a second circulation pump; 8-4-fifth circulation pump;
8-1-1-a first liquid inlet; 8-1-2-second liquid inlet; 8-1-3-stirrer; 8-1-4-a first drain outlet; 8-2-1-a second liquid outlet; 8-2-2-mud scraper; 8-2-3-a third liquid inlet; 8-2-4-slurry outlet.
Detailed Description
The following examples are provided to further understand the present invention, not to limit the scope of the present invention, but to provide the best mode, not to limit the content and the protection scope of the present invention, and any product similar or similar to the present invention, which is obtained by combining the present invention with other prior art features, falls within the protection scope of the present invention.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "connected" and "communicating" are to be interpreted broadly, e.g., as being either fixedly connected, detachably connected, or integrally connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
Example 1
The present embodiment provides a carbon dioxide capture system, as shown in fig. 1, comprising,
a pre-washing tower 1 for absorbing acid gas (SO) in the mixed gas2Gas and CO2A gas); a washing liquid storage device 1-1 is arranged in the pre-washing tower 1, the washing liquid storage device is respectively provided with a first washing liquid outlet 1-8 and a first air inlet 1-9, the first washing liquid outlet 1-8 is used for discharging washing liquid, and the first air inlet 1-9 sends mixed gas into the pre-washing tower; the prewashing tower is also internally provided with a first spraying device 1-3, a first washing liquid outlet 1-8 is communicated with the first spraying device 1-3 through a first circulating pump 1-7 and a first cooler 1-6, the first cooler 1-6 is used for cooling the washing liquid to keep the temperature of the washing liquid at 38-42 ℃, and the washing liquid passes through the first circulating pump 1-7 and the first coolerAfter the device 1-6, the mixed gas is sprayed out from the first spraying device 1-3 to be washed and the SO in the mixed gas is absorbed2Gas and CO2A gas; a pH monitor 1-10 is arranged between the first circulating pump 1-7 and the first cooler 1-6 and is used for monitoring the pH value of the washing liquid. In the embodiment, the first air inlet 1-9 is positioned below the first spraying device 1-3, the temperature of the cleaning solution passing through the first cooler is kept at 40 +/-1 ℃, and the mixed gas is in countercurrent contact with the solvent sprayed by the first spraying device 1-3.
A washing liquid recovery device 8 communicated with the prewashing tower 1; the washing liquid recovery device 8 comprises a reaction box 8-1 and a separation box 8-2 which are communicated, the reaction box 8-1 is communicated with the prewashing tower 1 through a first washing liquid outlet 1-8 and a first circulating pump 1-7, the first circulating pump 1-7 pumps part of washing liquid into the reaction box 8-1 for recovery, a stirrer 8-1-3 is further arranged in the reaction box 8-1, and the stirrer 8-1-3 is used for stirring the washing liquid in the reaction box 8-1 to promote the washing liquid to fully react with lime milk, so that the recovery rate of the washing liquid is improved, and meanwhile, the bottom of the washing tank is prevented from depositing; the reaction box 8-1 is also provided with a first liquid inlet 8-1-1 for introducing a solvent for recovering the washing liquid into the reaction box 8-1; the washing liquid in the pre-washing tower flows into the reaction box 8-1 from the second liquid inlet 8-1-2 of the reaction box through the first circulating pump 1-7 to react, the washing liquid after the reaction flows out from the first liquid discharge port 8-1-4 and flows into the separation box 8-2 through the third liquid inlet 8-2-3, the separation box 8-2 is internally provided with a mud scraper 8-2-2, the mud scraper 8-2-2 is driven by a motor to rotate slowly, can prevent the bottom of the separator from accumulating and scaling, is beneficial to solid-liquid separation, obtains recycled washing liquid and slurry after separation, discharges the recycled washing liquid from the second liquid outlet 8-2-1, joined with the scrubbing liquid flowing out of the first scrubbing liquid outlet 1-8, and the slurry is drawn off by the second circulation pump 8-3, which slurry can be used for treating SO.2The gas and the second circulating pump are mainly used for recycling the slurry. When pH monitor 1-10 monitors pH of the washing liquid to be 7-9, discharging part of the washing liquid to a washing liquid recovery device for recovery, and allowing the recovered washing liquid to flow into the pre-washing tower again, specifically, the washing liquid flows out from a first circulation pump 1-7 and is divided into two branches, and the first branch flows through a first cooler 1-6 and then is sprayed from a first sprayerSpraying the spraying device 1-3, allowing the second branch flow to enter a reaction box 8-1 for reaction, allowing the reacted washing liquid to enter a separation box 8-2 for separation to obtain recovered washing liquid and slurry, allowing the recovered washing liquid to be discharged from a second liquid discharge port 8-2-1, converging the washing liquid flowing out from a first washing liquid outlet 1-8, allowing the washing liquid to enter a first circulating pump 1-7 again, adjusting the valve openings of the first branch flow and the second branch flow of the first circulating pump, adjusting the flow rates of the first branch flow and the second branch flow, and further controlling the recovery amount of the washing liquid. In this embodiment, when the pH is less than 8, the washing solution is recovered, the washing solution can be, but is not limited to, an alkaline solvent, the washing solution in this embodiment is a NaOH solution, and the NaOH solution absorbs the acidic gas (SO) in the mixed gas2And CO2Gas) to form three solutions of sodium sulfate, sodium sulfite and sodium carbonate; the solvent for recycling the washing liquid is slaked lime solution, the slaked lime can be added by using the existing lime milk adding device, the slaked lime enters the reaction box 8-1 from the first liquid inlet 8-1-1, the slaked lime respectively reacts with sodium sulfate, sodium sulfite and sodium carbonate to obtain NaOH solution and slurry (the main components are calcium sulfite, calcium sulfate and calcium carbonate), the NaOH solution is recycled, when the concentration of the slurry reaches 5-10 wt%, the slurry is discharged from the slurry outlet 8-2-4 and can be used for recycling SO in a desulfurization absorption system2The second liquid outlet 8-2-1 is communicated with the first washing liquid outlet 1-8; the level of the liquid level in the reaction box is higher than that in the separation box; the ratio of the flow rate of the first substream to the flow rate of the second substream is 9: 1; the liquid level height of the washing liquid in the reaction box 8-1 is higher than that of the washing liquid in the separation box 8-2, the liquid level height of the washing liquid in the separation box 8-2 is higher than that of the washing liquid in the washing liquid storage device 1-1, and the washing liquid can flow into the separation box from the reaction box and then flow into the washing liquid storage device under the action of gravity.
An absorption tower 2 for absorbing CO in the mixed gas2And is communicated with the prewashing tower.
A regeneration tower 3 for regenerating CO2Absorption of solvent and recovery of CO2And is communicated with the absorption tower.
As another alternative, as shown in FIG. 2, a second washing liquid inlet 1-13 is further provided on the washing liquid storage device 1-1 of the pre-washing tower 1, the separation tank 8-2 is communicated with the washing liquid storage device 1-1 through a second liquid outlet 8-2-1, the separation tank 8-2 separates the washing liquid after washing the gas to obtain the recovered washing liquid and slurry, and the recovered washing liquid is recovered to the pre-washing tower through a second washing liquid inlet 1-13 for recycling.
As another alternative, as shown in FIG. 3, the washing liquid storage means 1-1 of the prewashing tower 1 is further provided with a second washing liquid outlet 1-12 and a first washing liquid inlet 1-11; the reaction box 8-1 is communicated with the second washing liquid outlet 1-12 through a fifth circulating pump 8-4, the separation box 8-2 is communicated with the first washing liquid inlet 1-11, when the pH of the washing liquid is between 7 and 9, under the action of the fifth circulating pump 8-4, part of the washing liquid is controlled to be discharged from the second washing liquid outlet, part of the washing liquid enters the washing liquid recovery device to be recovered, the part of the washing liquid firstly enters the reaction box 8-1 to react and then enters the separation box 8-2 to be separated, the separated washing liquid flows into the washing liquid storage device 1-1 through the first washing liquid inlet 1-11 again to be recycled, and the washing effect of the washing liquid is improved.
As a preferable embodiment, a first packing layer 1-2 and a first demisting device 1-4 are also arranged in the prewashing tower 1, the first packing layer 1-2 is arranged above the washing liquid storage device 1-1, the first packing layer 1-2 is arranged below the first spraying device 1-3, and the first demisting device 1-4 is arranged above the first spraying device 1-3; the first filler layer 1-2 can be one layer or a plurality of layers; the material of the first filler layer 1-2 is random packing; in the embodiment, the first packing layer is a layer made of PP plastic, and the first demisting device is a stainless steel wire mesh demister; the first inlet openings 1-9 are located below the first packing layer.
In a preferred embodiment, the top of the prewash tower 1 is provided with a first exhaust port 1-5, the absorption tower 2 is provided with a second intake port 2-7, and the prewash tower 1 and the absorption tower 2 are communicated through the first exhaust port 1-5 and the second intake port 2-7.
As a preferred embodiment of the method of the present invention,the absorption tower is internally provided with a rich liquid storage device 2-1, a second packing layer 2-2, a second spraying device 2-3 and a second demisting device 2-4 in sequence from bottom to top, the tower top of the absorption tower is also provided with a second exhaust port 2-6, and the second packing layer 2-2 is made of random or structured packing which can be one layer or multiple layers. In the embodiment, the second packing layer 2-2 is two layers and is made of a structured packing layer, the second demister 2-4 is a stainless steel wire gauze demister, and the second air inlet is positioned below the second packing layer; for absorbing CO2The gas solvent is alcohol amine solution, specifically organic amine mixed solution of monoethanolamine MEA, hindered amine AMP and piperazine PZ with molar ratio of 1:1:1, and absorbs CO2Forming a rich solution from the alcohol amine solution after the gas is gasified, and storing the rich solution in a rich solution storage device; the alcohol amine solution is sprayed out from the second spraying device to absorb CO in a countercurrent manner2A gas.
As a preferred embodiment, the carbon dioxide capturing system further comprises a first heat exchange device 4, and the absorption tower 2 and the regeneration tower 3 are communicated through the first heat exchange device 4; the absorption tower 2 is also provided with a rich liquid outlet 2-5, the regeneration tower 3 is provided with a lean liquid outlet 3-10 and a third spraying device 3-6, a hydrothermal inlet of the first heat exchange device 4 is communicated with the lean liquid outlet 3-10 through a fourth circulating pump 6, a hydrothermal outlet is communicated with the second spraying device 2-3 through a second cooler 7, a cold liquid inlet of the first heat exchange device 4 is communicated with the rich liquid outlet 2-5 through a third circulating pump 5, and a cold liquid outlet is communicated with the third spraying device 3-6; the rich liquid is sprayed out from the third spraying devices 3-6 after heat exchange by the first heat exchange device 4. The temperature in the regeneration tower is high, which is beneficial to CO2The gas is separated out from the rich liquid, the temperature in the absorption tower is low, and the CO is favorably separated out2The absorption of gas before entering the regeneration tower, the temperature of the rich liquid can be increased and the temperature of the lean liquid can be reduced after the heat exchange between the rich liquid and the lean liquid, which is beneficial to CO in the absorption tower2CO absorption and regeneration tower for gas2The separation of the gas and the heat exchange between the rich solution and the lean solution can also reduce the energy loss caused by heating the rich solution and cooling the lean solution.
As a preferred embodiment, a barren solution storage device 3-1, a gas-liquid distribution device 3-2, a third packing layer 3-4 and a fourth stripping layer are arranged in the regeneration tower from bottom to top in sequenceThe fog device 3-5, the third spray device 3-6 is arranged between the third packing layer 3-4 and the fourth demisting device 3-5; the gas-liquid distribution device 3-2 is also provided with a gas lifting cap 3-3, the gas lifting cap 3-3 is used for preventing the liquid sprayed by the third spraying device 3-6 from flowing into the barren solution storage device 3-1 and ensuring CO separated out from the tower bottom2The gas may flow from bottom to top. The regeneration tower is also provided with a liquid inlet hole 3-8 and a liquid outlet hole 3-7, the liquid inlet hole 3-8 and the liquid outlet hole 3-7 are respectively arranged at two sides of the gas-liquid distribution device 3-2, the liquid inlet hole 3-8 is arranged below the gas-liquid distribution device 3-2, a heater 3-9 is also arranged between the liquid inlet hole 3-8 and the liquid outlet hole 3-7, rich liquid is sprayed out from the third spraying device 3-6, stored on the gas-liquid distribution device after passing through a third packing layer, and enters the heater 3-9 through the liquid outlet hole 3-7 to be heated, so that CO in the rich liquid is sprayed out from the third spraying device 3-6 and then enters the2Separating out gas, changing rich solution into lean solution, feeding into lean solution storage device 3-1, and separating out CO2The gas is exhausted from a third exhaust port 3-11 after passing through the air lifting cap, the third packing layer and the third demisting device; the material of the third packing layers 3-4 is structured packing, which can be one layer or a plurality of layers. In this embodiment, the third packing layers 3 to 4 are made of stainless steel structured packing and have two layers, and the third demister is a stainless steel wire mesh demister.
Example 2
This example provides a method for capturing carbon dioxide using the carbon dioxide capturing system (fig. 1) provided in example 1, comprising the steps of,
the cleaning solution flows out through a first cleaning solution outlet and is sprayed out from a first spraying device, the mixed gas is introduced into the prewashing tower 1 through a first gas inlet, the mixed gas is in countercurrent contact with the cleaning solution, and the cleaning solution absorbs SO in the mixed gas2Gas and part of CO2Monitoring the pH value of the washing liquid during the washing process, when the pH value of the washing liquid is lower than 8, dividing the first circulating pump into a first branch flow and a second branch flow, wherein the flow ratio of the first branch flow to the second branch flow is 9:1, spraying the washing mixed gas from the first spraying device from the first branch flow, enabling the second branch flow to flow into a reaction box 8-1 to react with slaked lime, then enabling the reacted washing liquid to flow into a separation box to be separated, obtaining the recycled washing liquid and slurry, and washing the recycled washing liquid and slurryThe liquid is converged with the washing liquid flowing out from the washing liquid outlet, and then enters a first circulating pump until the washing liquid is strongly alkaline and the pH value reaches 11, the washing liquid is stopped to be led into a washing liquid recovery device, and the slurry is discharged and then recycled;
the washed mixed gas is conveyed into the absorption tower, the mixed gas flows from bottom to top, and the ethanolamine solution in the absorption tower is sprayed out from the second spraying device and is mixed with CO2Gas countercurrent contact for absorbing CO2Forming a rich solution by the ethanolamine solution after the gas is generated, storing the rich solution in a rich solution storage device, and exhausting the residual gas from a second exhaust port;
the rich liquid enters the regeneration tower after heat exchange, is sprayed out from the third spraying device, and after heating, CO is enabled to be generated2Gas is separated out from the rich solution, the rich solution forms a barren solution, the barren solution is stored in a barren solution storage device, flows out of the regeneration tower, enters the absorption tower after heat exchange, is sprayed out from the second spraying device, and reversely absorbs CO2A gas; recovered CO2And the gas is discharged from the third exhaust port and collected.
Example 3
This example provides a method for capturing carbon dioxide using the carbon dioxide capturing system (shown in fig. 3) provided in example 1, comprising the steps of,
the cleaning solution flows out through a first cleaning solution outlet and is sprayed out from a first spraying device, the mixed gas is introduced into the prewashing tower 1 through a first gas inlet, the mixed gas is in countercurrent contact with the cleaning solution, and the cleaning solution absorbs SO in the mixed gas2Gas and part of CO2Monitoring the pH value of the washing liquid during the process, when the pH value of the washing liquid is lower than 8, pumping part of the washing liquid into a reaction box 8-1 by a fifth circulating pump to react with slaked lime, then enabling the reacted washing liquid to flow into a separation box for separation to obtain recycled washing liquid and slurry, enabling the recycled washing liquid to flow into a washing liquid storage device 1-1 through a first washing liquid inlet 1-11, recycling until the pH value reaches 10, stopping introducing the washing liquid into a washing liquid recycling device, and discharging the slurry for recycling;
the washed mixed gas is conveyed into an absorption tower, the mixed gas flows from bottom to top, and the ethanolamine solution in the absorption towerSprayed out of the second spraying device and is mixed with CO2Gas countercurrent contact for absorbing CO2Forming a rich solution by the ethanolamine solution after the gas is generated, storing the rich solution in a rich solution storage device, discharging the residual gas from a second gas outlet, and collecting the residual gas;
the rich liquid enters the regeneration tower after heat exchange, is sprayed out from the third spraying device, and after heating, CO is enabled to be generated2Gas is separated out from the rich solution, the rich solution forms a barren solution which is stored in a barren solution storage device, the barren solution flows out of the regeneration tower, enters the absorption tower after heat exchange, is sprayed out from the second spraying device, and absorbs CO in a countercurrent mode2A gas.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications of the invention may be made without departing from the spirit or scope of the invention.

Claims (10)

1. A carbon dioxide capture system, comprising,
the pre-washing tower is used for absorbing acid gas in the mixed gas and reducing the temperature of the mixed gas; a washing liquid storage device is arranged at the bottom of the pre-washing tower, and a first washing liquid outlet is formed in the side surface of the washing liquid storage device;
a washing liquid recovery device communicated with the prewashing tower; the washing liquid recovery device comprises a reaction box and a separation box which are communicated, and the reaction box and the separation box are respectively communicated with the prewashing tower;
an absorption tower for absorbing CO in the mixed gas2In communication with the pre-scrubber;
regeneration column for recovery of CO2And is communicated with the absorption tower.
2. The carbon dioxide capture system of claim 1, wherein an agitator is disposed within the reaction tank;
a mud scraper is arranged in the separation box, and a slurry outlet is arranged at the bottom of the separation box.
3. The carbon dioxide capture system of claim 1 or 2, wherein a first packing layer, a first spraying device and a first demisting device are arranged in the prewashing tower from bottom to top in sequence;
the first spraying device is arranged above the washing liquid storage device;
the first washing liquid outlet is communicated with the first spraying device;
the top of the pre-washing tower is provided with a first exhaust port.
4. The carbon dioxide capture system according to any one of claims 1 to 3, wherein a rich liquid storage device, a second filler layer, a second spray device, a second demister and a second exhaust port are arranged in the absorption tower from bottom to top in sequence.
5. The carbon dioxide capture system of any one of claims 1 to 4, wherein a lean solution storage device, a third packing layer, a third spray device, a third demister and a third exhaust port are arranged in the regeneration tower from bottom to top in sequence.
6. The carbon dioxide capture system of claim 5, wherein the rich liquid storage device is provided with a rich liquid outlet, the rich liquid outlet being in communication with the third spraying device;
the barren liquor storage device is provided with a barren liquor outlet which is communicated with the second spraying device.
7. The carbon dioxide capture system of any of claims 1-6, wherein the regeneration tower is further provided with a gas-liquid distribution device, a liquid inlet hole and a liquid outlet hole;
a heater is arranged between the liquid outlet hole and the liquid inlet hole and used for recovering rich liquid;
the gas-liquid distribution device is arranged between the liquid outlet hole and the liquid inlet hole;
the liquid inlet hole is arranged below the third spraying device.
8. The carbon dioxide capture system of claim 6 or 7, further comprising a first heat exchange device having a hot liquid inlet in communication with the lean liquid outlet and a hot liquid outlet in communication with the second spray device;
and a cold liquid inlet of the first heat exchange device is communicated with the rich liquid outlet, and a cold liquid outlet of the first heat exchange device is communicated with the third spraying device.
9. A carbon dioxide capturing method characterized by using the carbon dioxide capturing system according to any one of claims 1 to 8, comprising the steps of,
washing the mixed gas with a washing solution, and then mixing with CO2The gas absorption solvent is contacted to absorb CO2Absorbing the solvent with gas to form a rich solution;
heating the rich liquid after heat exchange to make CO2Gas is separated out, and the rich solution becomes lean solution;
exchanging heat between lean solution and rich solution, cooling, and mixing with CO2Gas contact to absorb CO2A gas.
10. The method for capturing carbon dioxide according to claim 9, further comprising a step of recovering and reusing the washing liquid.
CN202010717898.XA 2020-07-23 2020-07-23 Carbon dioxide capture system and method Pending CN111729483A (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112680256A (en) * 2020-12-14 2021-04-20 长春东狮科技(集团)有限责任公司 Device and method for wet dechlorination and desulfurization of blast furnace gas
CN114307579A (en) * 2022-01-05 2022-04-12 南方电网电力科技股份有限公司 Desulfurization and carbon entrapment integration system
CN114669177A (en) * 2022-03-09 2022-06-28 中国矿业大学 Low-energy-consumption CO2Trapping and compression refining process
CN115090099A (en) * 2022-06-20 2022-09-23 江苏新世纪江南环保股份有限公司 Method for removing impurities in ammonia decarburization system
WO2024016502A1 (en) * 2022-07-18 2024-01-25 势加透博(北京)科技有限公司 Carbon dioxide trapping method and gas absorption system

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112680256A (en) * 2020-12-14 2021-04-20 长春东狮科技(集团)有限责任公司 Device and method for wet dechlorination and desulfurization of blast furnace gas
CN112680256B (en) * 2020-12-14 2022-06-14 长春东狮科技(集团)有限责任公司 Device and method for wet dechlorination and desulfurization of blast furnace gas
CN114307579A (en) * 2022-01-05 2022-04-12 南方电网电力科技股份有限公司 Desulfurization and carbon entrapment integration system
CN114669177A (en) * 2022-03-09 2022-06-28 中国矿业大学 Low-energy-consumption CO2Trapping and compression refining process
CN114669177B (en) * 2022-03-09 2024-01-26 中国矿业大学 Low-energy-consumption CO 2 Trapping and compression refining process
CN115090099A (en) * 2022-06-20 2022-09-23 江苏新世纪江南环保股份有限公司 Method for removing impurities in ammonia decarburization system
WO2024016502A1 (en) * 2022-07-18 2024-01-25 势加透博(北京)科技有限公司 Carbon dioxide trapping method and gas absorption system

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