CN116510467A - Carbon trapping system - Google Patents

Carbon trapping system Download PDF

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Publication number
CN116510467A
CN116510467A CN202310657978.4A CN202310657978A CN116510467A CN 116510467 A CN116510467 A CN 116510467A CN 202310657978 A CN202310657978 A CN 202310657978A CN 116510467 A CN116510467 A CN 116510467A
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China
Prior art keywords
liquid
spray tower
carbon
heat exchanger
flue gas
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CN202310657978.4A
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Chinese (zh)
Inventor
靳鑫
王兵
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Tsinghua University
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Tsinghua University
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Priority to CN202310657978.4A priority Critical patent/CN116510467A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation 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
    • B01D53/14—Separation 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 by absorption
    • B01D53/1412—Controlling the absorption process
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation 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
    • B01D53/002—Separation 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 by condensation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation 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
    • B01D53/14—Separation 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 by absorption
    • B01D53/1418—Recovery of products
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation 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
    • B01D53/14—Separation 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 by absorption
    • B01D53/18—Absorbing units; Liquid distributors therefor
    • B01D53/185—Liquid distributors
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation 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
    • B01D53/26—Drying gases or vapours
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/50—Carbon dioxide
    • C01B32/55—Solidifying
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2257/00—Components to be removed
    • B01D2257/80—Water
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2210/00—Purification or separation of specific gases
    • C01B2210/0001—Separation or purification processing
    • C01B2210/0009—Physical processing
    • C01B2210/0025—Physical processing by absorption in liquids
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2210/00—Purification or separation of specific gases
    • C01B2210/0043—Impurity removed
    • C01B2210/0062—Water
    • Y—GENERAL 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
    • Y02C20/00—Capture or disposal of greenhouse gases
    • Y02C20/40—Capture or disposal of greenhouse gases of CO2

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Analytical Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Treating Waste Gases (AREA)

Abstract

The application provides a carbon capture system, a drying tower, a main heat exchanger, spray tower equipment and carbon capture liquid supply equipment; the flue gas dehydrated by the drying tower enters a main heat exchanger, the main heat exchanger pre-cools the flue gas, the pre-cooled flue gas enters spray tower equipment, carbon trapping liquid is input into the spray tower equipment by carbon trapping liquid supply equipment in the spray tower equipment for cooling, carbon dioxide in the flue gas is cooled to the sublimation temperature of the carbon dioxide to obtain dry ice, the dry ice is liquefied to obtain liquid carbon dioxide, and the liquid carbon dioxide passes through the main heat exchanger to obtain high-concentration liquid carbon dioxide. Through the carbon capture system provided by the embodiment of the application, the evaporation capacity of the flue gas to the carbon capture liquid can be reduced.

Description

Carbon trapping system
Technical Field
The application relates to the technical field of carbon capture, in particular to a carbon capture system.
Background
At present, the desublimation method in the low-temperature carbon capture method is attracting more and more attention. The desublimation method is a method for collecting and recycling the de-sublimated dry ice by inputting the flue gas discharged from a power plant into low-temperature (the temperature is lower than 195k (-78.15 ℃) carbon collecting equipment and using carbon collecting liquid in box-type low-temperature carbon collecting equipment to desublimate carbon dioxide in the flue gas, but if the temperature of the flue gas is higher, the carbon collecting liquid is evaporated in the process of desublimating the carbon dioxide in the flue gas by the carbon collecting liquid, so that the collecting efficiency of the carbon collecting liquid on the carbon dioxide in the flue gas is reduced.
Disclosure of Invention
In order to solve the above problems, an object of an embodiment of the present application is to provide a carbon capture system.
In a first aspect, embodiments of the present application provide a carbon capture system comprising: a drying tower, a main heat exchanger, a spray tower device and a carbon trapping liquid supply device;
the drying tower, the main heat exchanger, the spray tower equipment and the carbon capture liquid supply equipment are connected in sequence;
the flue gas dehydrated by the drying tower enters the main heat exchanger, the main heat exchanger performs precooling treatment on the flue gas, the flue gas after precooling treatment enters the spray tower equipment, the carbon trapping liquid in the spray tower equipment is input into the spray tower equipment by the carbon trapping liquid supply equipment for cooling, carbon dioxide in the flue gas is cooled to the sublimation temperature of the carbon dioxide to obtain dry ice, the dry ice is liquefied to obtain liquid carbon dioxide, and the liquid carbon dioxide passes through the main heat exchanger to obtain high-concentration liquid carbon dioxide.
In the solution provided in the first aspect of the embodiment of the present application, the main heat exchanger disposed in the carbon capturing system is used to pre-cool the flue gas dehydrated by the drying tower, and compared with the mode that in the related art, the high-temperature flue gas is de-sublimated by the carbon capturing liquid, which causes a large amount of evaporation of the carbon capturing liquid, the main heat exchanger is used to pre-cool the flue gas before the flue gas enters the spray tower device, so as to reduce the temperature of the flue gas entering the spray tower device, so that the temperature of the flue gas entering the spray tower device is reduced, and in the process that the temperature of the flue gas reduced by the carbon capturing liquid is reduced to the de-sublimation temperature of carbon dioxide, the evaporation amount of the flue gas to the carbon capturing liquid can be reduced due to the reduced temperature difference between the flue gas and the carbon capturing liquid; and the dry ice after the carbon dioxide in the flue gas is sublimated is collected by utilizing the spray tower equipment, so that the defects of difficult dry ice collection, equipment corrosion and poor thermal conductivity caused by condensation of the dry ice on the inner wall surface of the box-type low-temperature carbon capture equipment in the process of capturing the dry ice by using the box-type low-temperature carbon capture equipment are avoided as much as possible.
In order to make the above objects, features and advantages of the present application more comprehensible, preferred embodiments accompanied with figures are described in detail below.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 shows a schematic structural diagram of a carbon capture system provided in embodiment 1 of the present application.
Detailed Description
In the description of the present application, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," etc. indicate or are based on the orientation or positional relationship shown in the drawings, merely for convenience of description and to simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present application.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.
In the present application, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. 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.
Carbon dioxide trapping is a research focus of carbon emission reduction technology, and has the relation of improving trapping efficiency and reducing equipment energy consumption to the prospect of industrial application and achievement of national double-carbon targets. The main carbon emission of China, which is the major carbon emission of China and the major coal emission of China, comes from coal burning power generation of a thermal power plant, and the carbon emission has the characteristics of large discharge amount, concentrated emission and lower carbon dioxide concentration. The carbon capture technology is mainly three, including: a pre-combustion trapping technique, an oxygen-enriched combustion trapping technique, and a post-combustion trapping technique. The trapping adaptability after combustion is better, and the existing power plant system is not required to be modified, so that the method is more suitable for the national conditions of China. Post-combustion trapping techniques can be subdivided into: absorption, adsorption, membrane separation, biological microalgae treatment, low temperature, etc.
In recent years, the desublimation method among the low temperature methods has been attracting attention. The desublimation method is a method for inputting flue gas discharged from a power plant into low-temperature (the temperature is lower than 195k (-78.15 ℃) carbon trapping equipment, and using carbon trapping liquid in the box-type low-temperature carbon trapping equipment to desublimate carbon dioxide in the flue gas to obtain solid dry ice of the carbon dioxide, thereby trapping and recycling the desublimated dry ice. The method has the characteristics of high trapping rate, high concentration of trapped carbon dioxide, no secondary pollutant, environment friendliness and the like. However, if the temperature of the flue gas is high, the carbon trapping liquid is evaporated in the process of sublimating carbon dioxide in the flue gas by the carbon trapping liquid, so that the trapping efficiency of the carbon trapping liquid on the carbon dioxide in the flue gas is reduced.
Based on this, the following embodiments of the present application provide a carbon capturing system, in which a main heat exchanger disposed in the carbon capturing system is utilized to pre-cool flue gas dehydrated by a drying tower, so as to reduce the temperature of flue gas entering a spray tower device, so that the temperature of flue gas entering the spray tower device is reduced, and in the process of reducing the temperature of flue gas entering the spray tower device to the carbon dioxide sublimation temperature by a carbon capturing liquid, the evaporation amount of flue gas to the carbon capturing liquid can be reduced due to the reduction of the temperature difference between the flue gas with the carbon capturing liquid, so as to improve the capturing efficiency of carbon dioxide in the flue gas by the carbon capturing liquid; and the dry ice after the carbon dioxide in the flue gas is sublimated is collected by utilizing the spray tower equipment, so that the defects of difficult dry ice collection, equipment corrosion and poor thermal conductivity caused by condensation of the dry ice on the inner wall surface of the box-type low-temperature carbon capture equipment in the process of capturing the dry ice by using the box-type low-temperature carbon capture equipment are avoided as much as possible.
In order to make the above objects, features and advantages of the present application more comprehensible, the present application is described in further detail below with reference to the accompanying drawings and examples.
Examples
Referring to the schematic structural diagram of the carbon capturing system shown in fig. 1, this embodiment proposes a carbon capturing system, including: a drying tower 1, a main heat exchanger 2, a spray tower device and a carbon capture liquid supply device.
The drying tower 1, the main heat exchanger 2, the spray tower equipment and the carbon trapping liquid supply equipment are connected in sequence.
The flue gas dehydrated by the drying tower 1 enters the main heat exchanger 2, the main heat exchanger 2 performs precooling treatment on the flue gas, the flue gas after precooling treatment enters the spray tower equipment, the carbon trapping liquid in the spray tower equipment, which is input into the spray tower equipment by the carbon trapping liquid supply equipment, is cooled, carbon dioxide in the flue gas is cooled to the sublimation temperature of carbon dioxide to obtain dry ice, the dry ice is liquefied to obtain liquid carbon dioxide, and the liquid carbon dioxide passes through the main heat exchanger 2 to obtain high-concentration liquid carbon dioxide.
In one embodiment, the high concentration of liquid carbon dioxide may refer to a low concentration of 80% or more of liquid carbon dioxide.
The drying tower 1 is used for removing water and drying the flue gas subjected to dust removal, desulfurization and denitrification so as to prevent the pipeline from generating ice blockage.
The main heat exchanger 2 is used for pre-cooling the dried flue gas, reducing the temperature of the flue gas, reducing the evaporation of carbon capture liquid in the next step, and recovering the cold energy of the decarbonized flue gas and liquid carbon dioxide.
For better desublimation of carbon dioxide in flue gas, the carbon capture liquid may be, but is not limited to: isopentane liquid or isopentane-n-pentane mixed liquid. Preferably, the isopentane liquid component is added to the carbon capture liquid when the carbon capture liquid is desired to have a low temperature and a high carbon capture rate.
Illustratively, when the carbon capture liquid is a low temperature isopentane liquid, the temperature of the low temperature isopentane liquid may be, but is not limited to: the temperature of the 80% carbon capture rate low temperature isopentane liquid was 168.15K (-105 ℃), the temperature of the 90% carbon capture rate low temperature isopentane liquid was 153.15K (-120 ℃), and the temperature of the 99% carbon capture rate low temperature isopentane liquid was 138.15K (-135 ℃).
In order to further improve the capturing efficiency of carbon dioxide in the flue gas, in the carbon capturing system provided in this embodiment, the spray tower device includes: a first spray tower 3 and a second spray tower 4; accordingly, the carbon capture liquid comprises: a first liquid trapping medium fed to the first spray tower 3 and a second liquid trapping medium fed to the second spray tower 4; the dry ice comprises: a first portion of dry ice from the first spray tower 3 and a second portion of dry ice from the second spray tower 4.
From the above description, it is clear that: the first liquid trapping medium and the second liquid trapping medium may be used separately but are not limited to: isopentane liquid or isopentane-n-pentane mixed liquid.
Alternatively, the first spray tower 3 and the second spray tower 4 may be separately employed as low-temperature spray towers.
In one embodiment, the first spray tower 3 and the second spray tower 4 are respectively provided with a solid-liquid collecting tank, a lower air inlet, an upper carbon capture liquid inlet, a nozzle and a top air outlet; wherein, the solid-liquid collecting vat sets up the bottom at first spray column 3 and second spray column 4 respectively, and the lower part air inlet can set up the lower part at first spray column 3 and second spray column 4 respectively and the air inlet mode of lower part air inlet is from supreme down, and upper portion carbon entrapment liquid entry can set up the upper portion at first spray column 3 and second spray column 4 respectively, and upper portion carbon entrapment liquid entry passes through hose connection with the nozzle, and the top gas outlet setting sets up the top at first spray column 3 and second spray column 4 respectively.
The top air outlet of the first spray tower 3 is connected with the lower air inlet of the second spray tower 4; the top gas outlet of the second spray tower 4 is connected with the main heat exchanger 2.
The first spray tower 3 is respectively connected with the main heat exchanger 2 and the second spray tower 4, and the first spray tower 3 and the second spray tower 4 are respectively connected with the carbon capture liquid supply equipment.
The first spray tower 3 is used for cooling the carbon dioxide gas in the flue gas to below a desublimation point by spraying a first liquid trapping medium with a first temperature under the atmospheric pressure, separating most of carbon dioxide in the flue gas in the form of dry ice, obtaining a first part of dry ice and collecting the first part of dry ice.
And the second spray tower 4 is used for cooling the carbon dioxide gas in the flue gas to below a desublimation point by spraying a second liquid trapping medium with a second temperature under the atmospheric pressure, and if necessary, the second liquid trapping medium with a lower temperature than the first liquid trapping medium sprayed by the first spray tower 3 can be used for desublimating the carbon dioxide in the cold flue gas, the residual carbon dioxide in the cold flue gas after the carbon trapping of the first spray tower 3 is subjected to secondary desublimation, and a second part of dry ice obtained after the secondary desublimation is collected.
The pre-cooled flue gas enters the first spray tower 3, the carbon dioxide in the flue gas is cooled to the sublimation temperature of the carbon dioxide by a first liquid trapping medium with a first temperature which is input into the first spray tower 3 in the first spray tower 3 by the carbon trapping liquid supply device, the first part of dry ice and cold flue gas are obtained, the first part of dry ice is liquefied to obtain liquid carbon dioxide of the first part of dry ice, the liquid carbon dioxide of the first part of dry ice is processed by the main heat exchanger to obtain high-concentration liquid carbon dioxide, and the cold flue gas is input into the second spray tower.
The carbon trapping liquid supply device inputs a first liquid trapping medium in the first spray tower 3, and sprays the first liquid trapping medium onto the flue gas by a nozzle in the first spray tower 3 to cool the flue gas. The cold flue gas is obtained after the flue gas is cooled in the first spray tower 3 by a first liquid trapping medium with a first temperature. The temperature of the cold flue gas is lower than that of the flue gas after the precooling operation.
Specifically, the pre-cooled flue gas enters a first spray tower 3 from a lower air inlet of the first spray tower 3, and is sprayed and cooled by a first liquid trapping medium with a first temperature, which is input into the first spray tower by the carbon trapping liquid supply device in the first spray tower 3, so as to obtain the first part of dry ice and cold flue gas; wherein the first liquid trapping medium is introduced into the first spray tower through an upper carbon trapping liquid inlet provided at an upper portion of the first spray tower 3.
For better collection of dry ice, the bottoms of the first spray tower 3 and the second spray tower 4 are respectively provided with a solid-liquid collecting tank (not shown in the figure). In the first spray tower 3, a first part of dry ice and a part of first liquid trapping medium fall into a bottom solid-liquid collecting tank, and flow out of the first spray tower 3 from the bottom of the solid-liquid collecting tank, and after the first part of dry ice flowing out of the first spray tower 3 is liquefied, liquid carbon dioxide of the first part of dry ice is obtained.
The cold flue gas output by the first spray tower 3 enters the second spray tower 4, the temperature of the cold flue gas is reduced by a second liquid trapping medium with a second temperature which is input into the second spray tower 4 by the carbon trapping liquid supply device in the second spray tower, the carbon dioxide in the cold flue gas is reduced to the sublimation temperature of the carbon dioxide, the second part of dry ice is obtained, the liquefied second part of dry ice is obtained, the liquid carbon dioxide of the second part of dry ice is obtained after the main heat exchanger 2 is processed, and the high-concentration liquid carbon dioxide is obtained; wherein the first temperature is higher than the second temperature.
In one embodiment, the first temperature is higher than the second temperature, but is both lower than the sublimation temperature of carbon dioxide. Specifically, cold flue gas is output from a top air outlet arranged at the top of the first spray tower 3, enters a second spray tower 4 from a lower air inlet of the second spray tower 4, is cooled by a second liquid trapping medium with a second temperature, which is input into the second spray tower 4 by the carbon trapping liquid supply device, in the second spray tower 4, and obtains the second part of dry ice; wherein the second liquid trapping medium is introduced into the second spray tower 4 through an upper carbon trapping liquid inlet provided at an upper portion of the second spray tower 4.
In the second spray tower 4, a second part of dry ice and a part of second liquid trapping medium fall into a solid-liquid collecting tank arranged in the second spray tower 4, and flow out of the second spray tower 4 from the bottom of the solid-liquid collecting tank, and after the second part of dry ice flowing out of the second spray tower 4 is liquefied, the liquid carbon dioxide of the second part of dry ice is obtained.
For example, if the first liquid trapping medium having the first temperature uses a low temperature isopentane liquid having a temperature of 168.15K (-105 ℃) and 80% carbon trapping rate, the second liquid trapping medium having the second temperature may use a low temperature isopentane liquid having a temperature of 153.15K (-120 ℃) and 90% carbon trapping rate, or a low temperature isopentane liquid having a temperature of 138.15K (-135 ℃) and 99% carbon trapping rate.
If the first liquid trapping medium having the first temperature uses a low temperature isopentane liquid having a temperature of 153.15K (-120 ℃) and a 90% carbon trapping rate, the second liquid trapping medium having the second temperature may use a low temperature isopentane liquid having a temperature of 138.15K (-135 ℃) and a 99% carbon trapping rate.
Moreover, the carbon dioxide in the cold flue gas sent to the second spray tower is not much and the temperature is lower, so the mass of the liquid drops of the second liquid trapping medium sprayed by the second spray tower is smaller than that of the first liquid trapping medium sprayed by the first spray tower.
In one embodiment, this drop mass can be adjusted according to the air intake, but the general principle is that the first spray tower 3 sprays more drops of the first liquid trapping medium than the second spray tower 4 sprays the second liquid trapping medium but the temperature of the first liquid trapping medium is higher than the temperature of the second liquid trapping medium.
Optionally, the first liquid trapping medium and the second liquid trapping medium have a droplet diameter of 2 mm or less.
As can be seen from the above description, the first spray tower 3 is larger in volume than the second spray tower 4 and the first liquid trapping medium in the first spray tower 3 is at a higher temperature than the second liquid trapping medium in the second spray tower 4. Then, the first spray tower 3 and the second spray tower 4 are used in series, the first spray tower 3 is used for removing most of carbon dioxide in the flue gas, and the rest enters the second spray tower 4 to carry out carbon capture by using carbon capture liquid with lower temperature. Illustratively, the first spray tower 3 is capable of desublimating 80% of the carbon dioxide in the flue gas, and the second spray tower 4 recondenses 90% of the carbon dioxide in the Hua Leng flue gas. Of course, the carbon capturing ratio of the first spray tower 3 and the second spray tower 4 may be freely adjusted according to actual needs, and carbon capturing may be performed by completely using the first spray tower 3. The main purpose of carbon capture of carbon dioxide using the first spray tower 3 and the second spray tower 4 in series is then to make the carbon capture amount of the carbon capture system more adjustable and to enable further energy savings.
The first spray tower 3 and the second spray tower 4 are arranged in a stepped mode, so that the carbon trapping rate of the carbon trapping system can reach 99%, and the carbon trapping device has the characteristics of higher carbon trapping rate and energy consumption saving.
In order to exhaust the flue gas after the carbon capturing operation obtained after the treatment in the first spray tower 3 and the second spray tower 4, the carbon capturing system provided in this embodiment further includes: a chimney connected to the main heat exchanger 2; the second spray tower 4 can obtain the second part of dry ice and obtain the flue gas after the carbon trapping operation, and the flue gas after the carbon trapping operation is discharged by the second spray tower 4 and then is discharged from the chimney after the heat exchange operation of the main heat exchanger 2. And the flue gas after the carbon trapping operation is discharged from a top gas outlet arranged at the top of the second spray tower 4.
The main heat exchanger 2 performs heat exchange operation on the flue gas after the carbon trapping operation (namely, the flue gas discharged from the top air outlet arranged at the top of the second spray tower 4), recovers the cold energy carried by the flue gas after the carbon trapping operation, and the recovered cold energy is used for pre-cooling the flue gas dehydrated by the drying tower. Therefore, the cold energy carried by the flue gas after the carbon trapping operation can be recycled, the carbon dioxide trapping efficiency is improved as much as possible, and the consumption of the carbon trapping liquid is not increased as much as possible, so that the method has the advantages of environment friendliness and energy conservation.
In order to be able to input a first liquid trapping medium having a first temperature to the first spray tower 3 and a second liquid trapping medium having a second temperature to the second spray tower 4, specifically, in the carbon trapping system proposed in the present embodiment, the carbon trapping liquid supply device includes: a first refrigeration heat exchanger 8 and a second refrigeration heat exchanger 13; the first refrigeration heat exchanger 8 is connected with the first spray tower 3; the second refrigeration heat exchanger 13 is connected with the second spray tower 4.
The first refrigeration heat exchanger 8 is capable of supplying a first liquid capturing medium having a first temperature to the first spray tower 3. The second refrigeration heat exchanger 13 is capable of supplying a second liquid capturing medium having a second temperature to the second spray tower 4.
In order to supplement the second liquid capturing medium in the second refrigeration heat exchanger 13, a carbon capturing liquid supplementing inlet is provided on the second refrigeration heat exchanger 13. By providing the carbon trapping liquid supplementing inlet on the second refrigeration heat exchanger 13, the carbon trapping liquid taken away or evaporated by the flue gas can be supplemented to ensure the carbon trapping efficiency of the carbon trapping system.
In order to liquefy the dry ice flowing out of the first spray tower 3 and the second spray tower 4, it is necessary to perform solid-liquid separation on the mixture of the first part of dry ice flowing out of the first spray tower 3 and part of the first liquid trapping medium and the mixture of the second part of dry ice flowing out of the second spray tower 4 and part of the second liquid trapping medium, respectively, that is: solid-liquid separation of dry ice and carbon capture liquid flowing out of the spray tower apparatus is required. In order to perform solid-liquid separation on dry ice and carbon trapping liquid flowing out of the spray tower apparatus, the carbon trapping system provided in this embodiment further includes: a circulation pump 5, a solid-liquid separator 6 and a melting pump 7.
The circulating pump 5 is respectively connected with the first spray tower 3, the second spray tower 4 and the solid-liquid separator 6; the solid-liquid separator 6 is also connected with the first refrigeration heat exchanger 8 and the melting pump 7; the melt pump 7 is also connected to the main heat exchanger 2.
A circulation pump 5 for conveying the dry ice and part of the carbon capture liquid mixture exiting the spray tower apparatus to a solid-liquid separator 6.
And the solid-liquid separator 6 is used for separating the dry ice from the carbon trapping liquid in a rolling mode.
And a melting pump 7 for liquefying the dry ice into liquid carbon dioxide and sending the liquid carbon dioxide to the main heat exchanger 2 for cold recovery.
The mixture of the dry ice and the carbon capture liquid flows out from the bottom of the first spray tower and the bottom of the second spray tower respectively, enters a solid-liquid separator 6 for solid-liquid separation after passing through a circulating pump 5, and is separated from the mixture of the dry ice and the carbon capture liquid.
Optionally, the solid-liquid separator 6 separates dry ice and a carbon-captured liquid from the mixture of dry ice and the carbon-captured liquid by means of rolling.
The separated dry ice is conveyed into the melting pump 7, the liquid carbon dioxide is obtained after the temperature is raised and liquefied by the melting pump 7, and the liquid carbon dioxide enters the main heat exchanger 2 and is obtained after the cold energy of the main heat exchanger 2 is recovered. The method can recycle the cold energy carried by the liquid carbon dioxide to be stored, can recycle the cold energy in the liquid carbon dioxide while completing carbon dioxide capture, and pre-cool the flue gas by utilizing the recycled cold energy, thereby having the advantages of green, environment protection and energy conservation.
The separated carbon capture liquid is input into the first refrigeration heat exchanger, cooled to a first temperature by the first refrigeration heat exchanger, and then conveyed into the first spray tower to sublimate the flue gas in the first spray tower. And the separated carbon trapping liquid is input into the first refrigeration heat exchanger, part of the carbon trapping liquid flowing out of the spray tower equipment is recycled, the supplementing amount of the carbon trapping liquid is reduced as much as possible, and the use cost of the carbon trapping system is reduced.
When the liquid carbon dioxide passes through the main heat exchanger, the main heat exchanger carries out heat exchange operation on the passing liquid carbon dioxide, the cold energy carried in the liquid carbon dioxide is recovered in a heat exchange operation mode, and the recovered cold energy is used for carrying out precooling treatment on the flue gas dehydrated by the drying tower. The method can recycle the cold energy carried by the liquid carbon dioxide to be stored, can recycle the cold energy in the liquid carbon dioxide while completing carbon dioxide capture, and pre-cool the flue gas by utilizing the recycled cold energy, thereby having the advantages of green, environment protection and energy conservation.
In order to cool down and recycle part of the carbon trapping liquid flowing out of the spray tower device, the carbon trapping system provided in this embodiment further includes: a first compressor 9, a second compressor 11, a first throttle valve 10 and a second throttle valve 12; the first compressor 9 and the first throttle valve 10 are connected with each other and are respectively connected with the first refrigeration heat exchanger 8; the second compressor 11 and the second throttle valve 12 are connected to each other and to the second refrigeration heat exchanger 13, respectively.
Specifically, the first refrigeration heat exchanger 8 and the second refrigeration heat exchanger 13 are also provided with: a refrigerant outlet and a refrigerant inlet; wherein the refrigerant outlet of the first refrigeration heat exchanger 8 is connected to one side of the first compressor 9 via a first throttle valve 10, and the other side of the first compressor is connected to the refrigerant inlet of the first refrigeration heat exchanger. The refrigerant outlet of the second refrigeration heat exchanger 13 is connected to one side of the second compressor 12 through the second throttle valve 12, and the other side of the second compressor 12 is connected to the refrigerant inlet of the second refrigeration heat exchanger 13.
The first compressor 9 and the first throttle valve 10 connected with the first refrigeration heat exchanger 8 are arranged, and the refrigerant output by the first compressor 9 is utilized to cool the part of the carbon trapping liquid flowing out of the spray tower equipment to the first temperature, so that the purpose of recycling the part of the carbon trapping liquid flowing out of the spray tower equipment is achieved.
The second refrigeration heat exchanger 13, the second compressor 12 and the second throttle valve 11 cool the isopentane liquid by exchanging heat with the refrigerant, and the isopentane liquid is supplemented by external addition. The temperature of the second liquid trapping medium sprayed by the second spray tower is lower than that of the first liquid trapping medium sprayed by the first spray tower, and the temperature of the second liquid trapping medium sprayed by the second spray tower is ensured to reach-120 ℃ or-135 ℃ by uniformly cooling down by the second compressor 12 in consideration of the difference between the temperatures of the carbon trapping liquids stored or used as described above, thereby ensuring higher carbon trapping rate.
According to the carbon trapping system, the spray tower equipment is adopted to directly spray the carbon trapping liquid to the pre-cooled flue gas, the carbon trapping liquid is used for desublimating and trapping carbon dioxide gas, and the dry ice formed by desublimation is brought out of the spray tower equipment by the carbon trapping liquid, so that the problems that the dry ice is difficult to collect and the heat conduction is affected by a dry ice layer due to condensation on the wall surface of the spray tower equipment are avoided; moreover, the first spray tower and the second spray tower are used in series, and the first spray tower and the second spray tower respectively use carbon capture liquid with different temperatures to capture carbon dioxide in the flue gas in a segmented mode, so that the carbon capture rate is improved, the refrigeration consumption is reduced, and the whole carbon capture system can select capture modes with different carbon capture rates according to actual requirements; furthermore, through setting up main heat exchanger, can carry out the precooling to the flue gas, and carry out the cold volume to flue gas and the liquid carbon dioxide after decarbonization and retrieve to at last provide the carbon dioxide liquid of high concentration, do benefit to the storage.
In summary, this embodiment proposes a carbon capturing system, pre-cooling the flue gas dehydrated by the drying tower by using a main heat exchanger disposed in the carbon capturing system, and compared with the mode that the high-temperature flue gas is greatly evaporated by using the carbon capturing liquid in the de-sublimation process in the related art, the method of pre-cooling the flue gas by using the main heat exchanger before the flue gas enters the spray tower device, so as to reduce the temperature of the flue gas entering the spray tower device, so that the temperature of the flue gas entering the spray tower device is reduced, and in the process that the temperature of the flue gas reduced by the carbon capturing liquid is reduced to the de-sublimation temperature of carbon dioxide, the evaporation amount of the flue gas to the carbon capturing liquid can be reduced due to the reduced temperature difference between the flue gas and the carbon capturing liquid; and the dry ice after the carbon dioxide in the flue gas is sublimated is collected by utilizing the spray tower equipment, so that the defects of difficult dry ice collection, equipment corrosion and poor thermal conductivity caused by condensation of the dry ice on the inner wall surface of the box-type low-temperature carbon capture equipment in the process of capturing the dry ice by using the box-type low-temperature carbon capture equipment are avoided as much as possible.
The foregoing is merely specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily think about changes or substitutions within the technical scope of the present application, and the changes and substitutions are intended to be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (10)

1. A carbon capture system, comprising: a drying tower, a main heat exchanger, a spray tower device and a carbon trapping liquid supply device;
the drying tower, the main heat exchanger, the spray tower equipment and the carbon capture liquid supply equipment are connected in sequence;
the flue gas dehydrated by the drying tower enters the main heat exchanger, the main heat exchanger performs precooling treatment on the flue gas, the flue gas after precooling treatment enters the spray tower equipment, the carbon trapping liquid in the spray tower equipment is input into the spray tower equipment by the carbon trapping liquid supply equipment for cooling, carbon dioxide in the flue gas is cooled to the sublimation temperature of the carbon dioxide to obtain dry ice, the dry ice is liquefied to obtain liquid carbon dioxide, and the liquid carbon dioxide passes through the main heat exchanger to obtain high-concentration liquid carbon dioxide for storage.
2. The carbon capture system of claim 1, wherein the carbon capture fluid comprises: a first liquid trapping medium and a second liquid trapping medium; the dry ice comprises: a first portion of dry ice and a second portion of dry ice;
the spray tower apparatus comprises: a first spray tower and a second spray tower;
the first spray tower is respectively connected with the main heat exchanger and the second spray tower, and the first spray tower and the second spray tower are respectively connected with the carbon trapping liquid supply equipment;
the pre-cooled flue gas enters a first spray tower, a first liquid trapping medium with a first temperature is input into the first spray tower by the carbon trapping liquid supply device in the first spray tower to cool, carbon dioxide in the flue gas is cooled to the sublimation temperature of the carbon dioxide to obtain a first part of dry ice and cold flue gas, the first part of dry ice is liquefied to obtain liquid carbon dioxide of the first part of dry ice, the liquid carbon dioxide of the first part of dry ice passes through the main heat exchanger to obtain high-concentration liquid carbon dioxide, and the cold flue gas is input into a second spray tower;
the cold flue gas enters the second spray tower, the second liquid trapping medium with a second temperature is input into the second spray tower by the carbon trapping liquid supply device in the second spray tower for cooling, carbon dioxide in the cold flue gas is cooled to the sublimation temperature of the carbon dioxide, so as to obtain second part of dry ice, the second part of dry ice is liquefied to obtain liquid carbon dioxide of the second part of dry ice, and the liquid carbon dioxide of the second part of dry ice passes through the main heat exchanger to obtain high-concentration liquid carbon dioxide; wherein the first temperature is higher than the second temperature.
3. The carbon capture system of claim 2, further comprising: a chimney connected to the primary heat exchanger;
the second spray tower can obtain the second part of dry ice and also obtain the flue gas after the carbon trapping operation, and the flue gas after the carbon trapping operation is discharged by the second spray tower and then is discharged from the chimney after the heat exchange operation of the main heat exchanger;
and the main heat exchanger carries out heat exchange operation on the flue gas passing through the carbon trapping operation, recovers cold energy carried by the flue gas after the carbon trapping operation, and the recovered cold energy is used for carrying out precooling treatment on the flue gas dehydrated by the drying tower.
4. The carbon capture system of claim 2, wherein the carbon capture liquid supply apparatus comprises: a first refrigeration heat exchanger 8 and a second refrigeration heat exchanger 13;
the first refrigeration heat exchanger is connected with the first spray tower; the second refrigeration heat exchanger is connected with the second spray tower;
the first refrigeration heat exchanger is capable of inputting a first liquid trapping medium with a first temperature to the first spray tower;
the second refrigeration heat exchanger is capable of inputting a second liquid capture medium having a second temperature to the second spray tower.
5. The carbon capture system of claim 4, further comprising: a circulation pump, a solid-liquid separator, and a melting pump;
the circulating pump is respectively connected with the first spray tower, the second spray tower and the solid-liquid separator; the solid-liquid separator is also connected with the first refrigeration heat exchanger and the melting pump; the melting pump is also connected with the main heat exchanger;
the mixture of the dry ice and the carbon capture liquid flows out from the bottom of the first spray tower and the bottom of the second spray tower respectively, enters a solid-liquid separator for solid-liquid separation after passing through a circulating pump, and is separated from the mixture of the dry ice and the carbon capture liquid;
the separated dry ice is conveyed into the melting pump, the liquid carbon dioxide is obtained after the temperature is raised and liquefied by the melting pump, and the liquid carbon dioxide enters the main heat exchanger and is obtained after the cold energy of the main heat exchanger is recovered;
the separated carbon capture liquid is input into the first refrigeration heat exchanger, cooled to a first temperature by the first refrigeration heat exchanger, and then conveyed into the first spray tower to sublimate the flue gas in the first spray tower.
6. The carbon capture system of claim 5, wherein the primary heat exchanger exchanges heat with the passing liquid carbon dioxide, recovers cold energy carried in the liquid carbon dioxide by way of the exchange operation, and the recovered cold energy is used for pre-cooling flue gas dehydrated by the drying tower.
7. The carbon capture system of claim 5, wherein the solid-liquid separator separates the dry ice and the carbon capture fluid from the mixture of dry ice and the carbon capture fluid by rolling.
8. The carbon capture system of claim 4, wherein a carbon capture liquid make-up inlet is provided on the second refrigeration heat exchanger.
9. The carbon capture system of claim 4, further comprising: a first compressor, a second compressor, a first throttle valve, and a second throttle valve;
the first compressor and the first throttle valve are connected with each other and are respectively connected with the first refrigeration heat exchanger;
the second compressor and the second throttle valve are connected with each other and are respectively connected with the second refrigeration heat exchanger.
10. The carbon capture system of any one of claims 1-9, wherein the carbon capture fluid is an isopentane fluid or an isopentane-n-pentane mixed fluid.
CN202310657978.4A 2023-06-05 2023-06-05 Carbon trapping system Pending CN116510467A (en)

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Application Number Priority Date Filing Date Title
CN202310657978.4A CN116510467A (en) 2023-06-05 2023-06-05 Carbon trapping system

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Application Number Priority Date Filing Date Title
CN202310657978.4A CN116510467A (en) 2023-06-05 2023-06-05 Carbon trapping system

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