System and method for capturing carbon dioxide

Abstract

The invention relates to the technical field of carbon dioxide trapping, in particular to a system and a method for trapping carbon dioxide. The system comprises an absorption tower which is provided with a gas inlet and a gas outlet which are oppositely arranged along the transverse direction of the absorption tower; the gas absorption assembly is arranged in the absorption tower, the gas absorption assembly comprises a liquid supply part and a spraying part, and the liquid supply part is communicated with the spraying part; the speed control assembly comprises a spraying control part arranged on the spraying part and a liquid supply control part optionally arranged on the liquid supply part, so that the speed control assembly is used for controlling intermittent spraying of the carbon dioxide absorbent in the gravity direction and controlling intermittent spraying of the carbon dioxide absorbent in the horizontal direction of the absorption tower; the spraying density of the carbon dioxide absorbent flowing out of the spraying piece is gradually increased. The system provided by the invention can solve the problems of high energy consumption, short replacement time and high maintenance cost of the existing absorption tower, and can realize high carbon dioxide capture efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon dioxide capture, and in particular to a system and method for capturing carbon dioxide. Background Art

[0002] Liquid adsorption of carbon dioxide from air refers to an emerging technology that uses chemical adsorbents to capture carbon dioxide from the air (L-DAC). When air passes through the surface of the chemical adsorbent, carbon dioxide reacts chemically with the solution. Chemical adsorbents include alkaline hydroxide solutions (KOH, NaOH, etc.), amine solutions (alkanolamine, ethanolamine, etc.), amino acid salt solutions, etc. The principle of L-DAC technology is as follows Figure 1 As shown, a chemical adsorbent first flows through the packing inside the air absorption tower, capturing carbon dioxide entering the absorption tower from the bottom of the absorption tower to form a carbon dioxide absorption liquid. The carbon dioxide captured by the adsorbent is then reduced and precipitated. The chemical adsorbent, after the reduction of the carbon dioxide absorption liquid, continues to capture carbon dioxide from the air inlet. The chemical adsorbent is sprayed inside the absorption tower, reacting with the carbon dioxide in the air as it flows from top to bottom through the packing.

[0003] However, in the height direction of the absorption tower, due to the effect of gravity, the concentration of the adsorbent solution tends to form a gradient when it flows from top to bottom, resulting in a saturated carbon dioxide capture rate in the solution air above the absorption tower and insufficient carbon dioxide utilization in the air below. In addition, in the radial depth direction of the absorption tower, the uneven distribution of airflow caused by the resistance of the filler will cause local wind speed differences, further resulting in a decrease in the contact efficiency between the adsorbent and carbon dioxide, affecting the overall capture performance. In response to the above problems, existing processes have attempted to alleviate them by optimizing the tower structure or improving the adsorbent formula, but have failed to fundamentally solve the problem of mismatch between the spraying method and the multi-dimensional fluid dynamics in the tower.

[0004] Therefore, a new carbon dioxide capture method is urgently needed to reduce energy consumption and maintenance costs, while improving the uniformity and stability of carbon dioxide capture efficiency. Summary of the Invention

[0005] The present invention aims to overcome the above-mentioned problems existing in the prior art and provide a system and method for capturing carbon dioxide. The system and method for capturing carbon dioxide of the present invention can reduce energy consumption and maintenance costs while also improving carbon dioxide capture efficiency.

[0006] In the existing methods for capturing carbon dioxide, the inlet of the carbon dioxide-containing gas is generally set at the bottom of the absorption tower, and the outlet is generally set at the top of the absorption tower. That is, the carbon dioxide-containing gas generally flows upward from the bottom of the absorption tower to contact the carbon dioxide absorbent. The inventors of the present invention found in their research that the setting of the inlet and outlet has the disadvantage that the absorbed gas will diffuse outside the absorption tower, causing gas reflux, affecting the concentration of carbon dioxide around the absorption tower, and thus reducing the carbon dioxide absorption efficiency. In addition, in order to more effectively capture carbon dioxide in the existing process, multiple carbon dioxide absorbent spray assemblies are generally distributed from top to bottom in the absorption tower to continuously spray carbon dioxide. However, continuous spraying increases the energy consumption, replacement and maintenance costs of the absorption tower.

[0007] The inventors of the present invention conducted further in-depth research and found that the use of a speed control component to control the intermittent spraying of carbon dioxide absorbent in the absorption tower can reduce the energy consumption, replacement and maintenance costs of the absorption tower. Furthermore, by setting the positions of the air inlet and the air outlet to laterally capture the gas containing carbon dioxide, and controlling the spraying speed of the carbon dioxide absorbent in different dimensions through the speed control component, that is, controlling the spraying density in different dimensions, it is possible to achieve high capture efficiency while reducing energy consumption.

[0008] In order to achieve the above objectives, the present invention provides a system for capturing carbon dioxide in a first aspect, the system comprising:

[0009] An absorption tower, the absorption tower having an air inlet and an air outlet, the air inlet and the air outlet being arranged opposite to each other in a transverse direction of the absorption tower;

[0010] A gas absorption assembly is disposed in the absorption tower and includes a liquid supply component and a spray component. The liquid supply component is in communication with the spray component and is configured to provide a carbon dioxide absorbent to flow out of the spray component along the direction of gravity to contact the carbon dioxide-containing gas to capture carbon dioxide from the air.

[0011] A speed control component includes a spray control component provided on the spray member, and optionally a liquid supply control component provided on the liquid supply member, for controlling the intermittent spraying of the carbon dioxide absorbent along the direction of gravity, and controlling the spray density of the carbon dioxide absorbent flowing out of the spray member to gradually increase along the horizontal direction of the absorption tower.

[0012] A second aspect of the present invention provides a method for capturing carbon dioxide, comprising: contacting carbon dioxide-containing gas flowing horizontally through an absorption tower with a carbon dioxide absorbent flowing out intermittently in the direction of gravity; wherein the spray density of the carbon dioxide absorbent gradually increases along the horizontal direction of the absorption tower.

[0013] Through the above technical solution, the present invention has at least the following advantages compared with the prior art:

[0014] The present invention controls the intermittent spraying of the carbon dioxide absorbent through a speed control component, which can solve the current problems of high energy consumption, short replacement time and high maintenance cost of the absorption tower. In addition, the air inlet and the air outlet on the absorption tower are relatively arranged along the horizontal direction of the absorption tower, that is, the carbon dioxide absorbent is controlled to capture carbon dioxide in the gas flowing horizontally through the absorption tower. At the same time, the speed control component is used to control the spray density of the carbon dioxide absorbent flowing out of the spray part along the horizontal direction of the absorption tower to gradually increase, which can achieve high carbon dioxide capture efficiency. The reason is that the method of the present invention can solve the problems of solution gradient changes and wind speed differences caused by the height and depth of the absorption tower. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Shown is a schematic diagram of the L-DAC technical principle in the background art.

[0016] Figure 2 Shown is a front view of a system for capturing carbon dioxide in accordance with some embodiments of the present invention.

[0017] Figure 3 Shown is a front cross-sectional view of a system for capturing carbon dioxide according to some embodiments of the present invention.

[0018] Figure 4 Shown is a left side view of a system for capturing carbon dioxide according to some embodiments of the present invention.

[0019] Figure 5 Shown is a right side view of a system for capturing carbon dioxide in accordance with some embodiments of the present invention.

[0020] Description of Reference Numerals

[0021] 1. Absorption tower 2. Air inlet 3. Air outlet

[0022] 4. Fan 5. Sprayer 6. Sprayer inlet pipeline

[0023] 7. Packing layer 8. Carbon dioxide absorbent container DETAILED DESCRIPTION

[0024] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention. In this article, unless otherwise specified, data ranges include endpoints.

[0025] In the present invention, unless otherwise specified, "spray density" is defined as the spray volume of the carbon dioxide adsorbent per square meter of space at the bottom of the filler within one hour.

[0026] A first aspect of the present invention provides a system for capturing carbon dioxide, the system comprising:

[0027] The absorption tower 1 has an air inlet 2 and an air outlet 3, and the air inlet 2 and the air outlet 3 are arranged opposite to each other along the transverse direction of the absorption tower 1;

[0028] The gas absorption assembly is disposed in the absorption tower 1 and includes a liquid supply component and a spray component 5. The liquid supply component is connected to the spray component 5 and is used to provide a carbon dioxide absorbent to flow out of the spray component 5 along the direction of gravity to contact the carbon dioxide-containing gas to capture carbon dioxide;

[0029] The speed control component includes a spray control component arranged on the spray member 5, and optionally a liquid supply control component arranged on the liquid supply member, for controlling the intermittent spraying of the carbon dioxide absorbent along the direction of gravity, and controlling the spray density of the carbon dioxide absorbent flowing out of the spray member 5 to gradually increase along the horizontal direction of the absorption tower 1.

[0030] The system of the present invention can improve the capture efficiency of carbon dioxide while reducing energy consumption. The reason for this is that the air inlet 2 and the air outlet 3 of the present invention are arranged relative to each other along the horizontal direction of the absorption tower 1, which enables the system of the present invention to directly flow the gas after the carbon dioxide is captured to a distant place when absorbing gas, avoiding the formation of air backflow, which affects the carbon dioxide concentration in the absorption tower 1 and causes the problem of low capture efficiency. At the same time, the speed control component controls the horizontal direction of the absorption tower 1, and the spray density of the carbon dioxide absorbent flowing out of the spray part 5 gradually increases, which can solve the problem of different wind speeds caused by the horizontal filling depth of the absorption tower 1, and better improve the efficiency of capturing carbon dioxide.

[0031] According to the present invention, "optionally" means that a certain technical feature or step can be selectively adopted when implementing the scheme. In the present invention, the intermittent spraying of the carbon dioxide absorbent can be controlled by the liquid supply control component provided on the liquid supply component. When the liquid supply control component is not provided on the liquid supply component, the intermittent spraying of the carbon dioxide absorbent can be controlled by the spray control component provided on the spray component 5, and the speed and time of the spraying can be controlled.

[0032] According to the present invention, specifically, in some embodiments, during the process of capturing carbon dioxide-containing gas using a carbon dioxide capture system, carbon dioxide absorbent is supplied to the spray part 5 through the liquid supply part, and at the same time, the spray part 5 is controlled to intermittently spray the carbon dioxide absorbent in conjunction with the speed control component, so that the carbon dioxide absorbent flowing out of the spray part 5 along the gravity direction contacts with the carbon dioxide-containing gas flowing horizontally through the absorption tower 1 to capture carbon dioxide, and at the same time, the spray density of the carbon dioxide absorbent flowing out of the spray part 5 along the horizontal direction of the absorption tower 1 is gradually increased by controlling the speed control component.

[0033] According to the present invention, in some embodiments, the gas absorption assembly further includes a packing layer 7 , and the packing layer 7 is located below the corresponding spraying element 5 .

[0034] According to the present invention, specifically, in some embodiments, during the carbon dioxide capture process, the carbon dioxide absorbent falls from the spray element 5 to the corresponding packing layer 7 in the form of droplets and flows in the packing layer 7 in the form of a liquid film. The carbon dioxide-containing gas is in full contact with the carbon dioxide absorbent in the absorption tower 1, especially in the packing layer 7, so that the carbon dioxide in the gas fully reacts with the effective ingredients in the carbon dioxide absorbent, thereby capturing the carbon dioxide.

[0035] According to the present invention, the packing layer 7 is a conventional packing layer 7 in the art, including but not limited to a packing layer 7 filled with polyvinyl chloride material. It is known to those skilled in the art that the lateral depth of the packing layer 7 generally satisfies η=a*h. b , η is the absorption efficiency, a and b are constants, h is the lateral depth of the packing, a and b are related to the specific filling method, etc., and those skilled in the art can determine them according to actual conditions. When the absorption tower 1 reaches a certain depth, that is, when the packing layer 7 is filled with a certain lateral depth, the absorption efficiency increases less. At this time, the lateral depth of the packing layer 7 is determined. This filling method is a conventional filling method in the field. The present invention has no special restrictions on the packing layer 7 and will not be elaborated here.

[0036] According to the present invention, in some embodiments, at least m groups of gas absorption components with different longitudinal heights are arranged in the vertical direction of the absorption tower 1, where m is an integer not less than 2, and preferably m is an integer of 2-7, for example, 2, 3, 4, 5, 6 or 7.

[0037] In the present invention, at least m groups of gas absorption components with different vertical heights are arranged along the vertical direction of the absorption tower 1 so as to fully capture the carbon dioxide in the gas by spraying the carbon dioxide adsorbent.

[0038] According to the present invention, the liquid supply part and the spray part 5 can be conventional components in the field. For example, the spray part 5 can have multiple nozzles, and the liquid supply part can be a pipeline equipped with a pump. In some embodiments, the spray part 5 in the gas absorption component includes several nozzles arranged in a matrix along the cross-section of the absorption tower 1.

[0039] In the present invention, "several nozzles arranged in a matrix" refers to a row of nozzles arranged in a straight line continuously along the transverse direction of the absorption tower, and a row of nozzles arranged in a straight line continuously along the wide diameter direction (width direction or radial direction) of the absorption tower. As long as the purpose of the present invention can be achieved, the number of nozzles arranged in a row of nozzles in a straight line continuously in the transverse direction and the number of nozzles arranged in a row of nozzles in a straight line continuously in the wide diameter direction are not particularly limited. In some embodiments, the number of nozzles arranged in a straight line continuously in the transverse direction is an integer between 2 and 50, preferably an integer between 5 and 20; in some embodiments, the number of nozzles arranged in a straight line continuously in the wide diameter direction (width direction or radial direction) is an integer between 2 and 50, preferably an integer between 10 and 30; in addition, as long as the purpose of the present invention can be achieved, the distance between each nozzle is not particularly limited, and preferably is evenly distributed.

[0040] According to the present invention, in order to fully capture carbon dioxide, in some embodiments, a group of gas absorption components is disposed on the top of the absorption tower 1 .

[0041] According to the present invention, multiple groups of gas absorption components may be distributed at equal intervals or not. Preferably, in some embodiments, when m is 2, along the vertical direction of the absorption tower 1, the distance between two groups of gas absorption components Δh ≥ 0.5*h (for example, Δh = (0.5-0.8)*h, and the values ​​of Δh that can be cited include 0.5*h, 0.55*h, 0.6*h, 0.63*h, 0.7*h, 0.75*h or 0.8*h, etc.), where h is the height of the absorption tower 1; when m is an integer greater than 2, along the vertical direction of the absorption tower 1, the spacing between two adjacent groups of gas absorption components is recorded as Δh1 to Δh i , i is m-1, and Δh1 to Δh i The values ​​of Δh decrease in sequence, preferably i ≥0.5*(h-∑Δh i-1 ), such as Δh i =(0.5-0.8)*(h-∑Δh i-1 ).

[0042] According to the present invention, specifically, in some embodiments, when m is 3, along the vertical direction of the absorption tower, from top to bottom, the first gas absorption assembly is arranged at the top of the absorption tower, and the distance between the first gas absorption assembly and the second group of gas absorption assembly Δh1 = (0.5-0.8)*h, h is the height of the absorption tower, and the distance between the second gas absorption assembly and the third group of gas absorption assembly Δh2 = (0.5-0.8)*(h-Δh1); when m is 4, along the vertical direction of the absorption tower, from top to bottom, the first gas absorption assembly is arranged at the top of the absorption tower, and the distance between the first gas absorption assembly and the second group of gas absorption assembly Δh1 = (0.5-0.8)*h, h is the height of the absorption tower, the distance between the second gas absorption assembly and the third group of gas absorption assembly Δh2 = (0.5-0.8)*(h-Δh1), and the distance between the third gas absorption assembly and the fourth group of gas absorption assembly Δh3 = (0.5-0.8)*[h-(Δh1+Δh2)].

[0043] According to the present invention, in some embodiments, the speed control component is further used to control the spray density of the carbon dioxide absorbent in the m-1th group of spray elements 5 to be no lower than the spray density of the carbon dioxide absorbent in the mth group of spray elements 5 .

[0044] In the present invention, the speed control component controls the spray density of the carbon dioxide absorbent in the m-1 group of spray elements 5 to be no lower than the spray density of the carbon dioxide absorbent in the m group of spray elements 5, which can save energy and better improve the carbon dioxide capture efficiency.

[0045] According to the present invention, the speed control component may be a control valve installed on a corresponding component. In some embodiments, the spray control component includes a flow control valve provided on a spray head.

[0046] In the present invention, by controlling the opening, closing and opening size of the flow control valve provided on the nozzle, different flow rates of the carbon dioxide absorbent flowing out of the nozzle can be achieved, that is, the spray density of the carbon dioxide absorbent flowing out of the spray piece 5 can be gradually increased along the horizontal direction of the absorption tower 1. The speed control component can also be used to control the spray density of the carbon dioxide absorbent in the m-1 group of spray pieces 5 to be not lower than the spray density of the carbon dioxide absorbent in the m group of spray pieces 5, and the spray density of multiple nozzles in the width direction (or radial direction) of the absorption tower 1 to be the same.

[0047] According to the present invention, as long as the purpose of the present invention can be achieved, the absorption tower 1 can be any absorption tower 1 in the art. In some embodiments, the cross-section of the absorption tower 1 is square or circular, that is, the absorption tower 1 can be a rectangular or cylindrical absorption tower 1.

[0048] According to the present invention, in some embodiments, the cross section of the absorption tower 1 is square.

[0049] According to the present invention, in some embodiments, the air inlet 2 is provided at a partial side inlet of the absorption tower 1 .

[0050] In the present invention, the air inlet 2 is set at a part of the side inlet of the absorption tower 1, which can expand the range of the air inlet 2 and more effectively capture the carbon dioxide in the gas. For example, when the absorption tower 1 is a rectangular parallelepiped, its air inlet 2 is a vertical side of the rectangular parallelepiped.

[0051] According to the present invention, in some embodiments, the air outlet 3 is in a contraction shape, for example, the outlet is a prism.

[0052] In the present invention, energy loss can be reduced by optimizing the outlet shape, that is, the tapered structure. Specifically, in some embodiments, when the absorption tower 1 is a rectangular parallelepiped, its air inlet 2 is a vertical side surface of the rectangular parallelepiped, and the other vertical side surface arranged laterally opposite to the air inlet 2 serves as the bottom surface, gradually shrinking into a prism-shaped outlet.

[0053] According to the present invention, in some embodiments, the system of the present invention further includes: a gas conveying device, which is arranged at the air inlet 2 and / or the air outlet 3, so as to convey the carbon dioxide-containing gas into the absorption tower 1 through the air inlet 2 for contact to capture the carbon dioxide and then continue to convey it outside the system.

[0054] According to the present invention, in some embodiments, the gas delivery device includes a fan 4 disposed at the gas outlet 3 .

[0055] According to the present invention, specifically, in some embodiments, when the absorption tower 1 is a rectangular parallelepiped, its air inlet 2 is a vertical side surface of the rectangular parallelepiped, and the other vertical side surface arranged laterally opposite to the air inlet 2 serves as the bottom surface. The size of the fan 4 serves as the top surface of the prism, which shrinks into a prism-shaped outlet. The fan 4 draws the carbon dioxide-containing gas into the absorption tower 1 from the air inlet 2 to form a gas flow, and captures the carbon dioxide therein through the carbon dioxide adsorbent.

[0056] According to the present invention, in some embodiments, the system of the present invention further comprises a carbon dioxide absorbent containing device 8, which is disposed at the bottom of the absorption tower 1 to contain the carbon dioxide absorbent and the carbon dioxide absorbent after capturing carbon dioxide.

[0057] According to the present invention, in some embodiments, when the system of the present invention is started, all the carbon dioxide absorbent is in the carbon dioxide absorbent containing device 8, a certain amount of carbon dioxide absorbent is supplied to the liquid supply part and transported to each spray part 5, and at the same time contacts with the gas containing carbon dioxide to capture carbon dioxide, and the rich liquid after the contact is completed flows into the carbon dioxide absorbent containing device 8 again to mix with the remaining carbon dioxide adsorbent, and continues to circulate and contact with the gas containing carbon dioxide until all the effective components in the carbon dioxide absorbent containing device 8 are consumed.

[0058] A second aspect of the present invention provides a method for capturing carbon dioxide, comprising: contacting carbon dioxide-containing gas flowing horizontally through an absorption tower with a carbon dioxide absorbent that flows out intermittently in the direction of gravity; wherein the spray density of the carbon dioxide absorbent gradually increases along the horizontal direction of the absorption tower.

[0059] According to the present invention, the carbon dioxide absorbent flows out intermittently in the direction of gravity. The carbon dioxide absorbent flowing out for the first time flows through the absorption tower and reacts with the carbon dioxide in the carbon dioxide-containing gas flowing horizontally through the absorption tower. After flowing out for a period of time, the spraying is suspended. At this time, the carbon dioxide absorbent flowing out for the first time absorbs carbon dioxide and then slowly flows downward by its own gravity to continue absorbing carbon dioxide in the gas. After suspending the flow for a period of time, it continues to flow out, thereby achieving a solution for capturing the carbon dioxide absorbent that intermittently flows out of the carbon dioxide absorption tower. More importantly, the present invention has found through in-depth research that after the carbon dioxide-containing gas flows horizontally through the absorption tower and captures the carbon dioxide, it can flow directly to a distant place, avoiding the formation of air backflow at the air outlet of the absorption tower, affecting the carbon dioxide concentration in the absorption tower and causing low capture efficiency. At the same time, the solution of gradually increasing the spray density of the carbon dioxide absorbent along the horizontal direction of the absorption tower can better improve the capture efficiency of carbon dioxide. The reason is that in the setting of the horizontal gas capture carbon dioxide absorption tower, the wind speed at the air inlet is lower than the wind speed at the air outlet, and the spray density of the chemical absorbent is set at different horizontal depths inside the absorption tower. The spray density of the carbon dioxide absorbent at the air inlet of the absorption tower to the spray density of the chemical absorbent at the air outlet of the absorption tower is set from small to large. The carbon dioxide absorbent reacts with the carbon dioxide in the gas in the absorption tower. Therefore, the different horizontal spray densities of the chemical absorbent can solve the problem of different wind speeds caused by the horizontal depth of the absorption tower, thereby better improving the efficiency of capturing carbon dioxide.

[0060] According to the present invention, in some embodiments, the difference between the initial spray density of the carbon dioxide absorbent and the final spray density of the carbon dioxide absorbent along the horizontal direction of the absorption tower is 0.01-17m 3 ·m -2 ·h -1 , for example 0.01m 3 ·m-2 ·h -1 , 0.1m 3 ·m -2 ·h -1 , 0.9m 3 ·m -2 ·h -1 , 1m 3 ·m -2 ·h -1 , 1.3m 3 ·m -2 ·h -1 , 2m 3 ·m -2 ·h -1 , 3m 3 ·m -2 ·h -1 , 4m 3 ·m -2 ·h -1 , 5m 3 ·m -2 ·h -1 5.6m 3 ·m -2 ·h -1 , 8m 3 ·m -2 ·h -1 、10m 3 ·m -2 ·h -1 、12.8m 3 ·m -2 ·h -1 、15m 3 ·m -2 ·h -1 、17m 3 ·m -2 ·h -1 , or the range of any two values ​​above, preferably 0.05-5m 3 ·m -2 ·h -1 .

[0061] According to the present invention, it can be understood that the initial spray density of the carbon dioxide absorbent refers to the spray density of carbon dioxide at the air inlet end along the horizontal direction of the absorption tower, and the termination spray density refers to the spray density of carbon dioxide at the air outlet end along the horizontal direction of the absorption tower. In the present invention, the difference between the initial spray density of the carbon dioxide absorbent and the termination spray density of the carbon dioxide absorbent is controlled within the above range, which can better improve the carbon dioxide capture efficiency.

[0062] According to the present invention, multiple groups of lateral outflow sources can be arranged along the horizontal direction of the absorption tower, that is, in the horizontal direction, so that the spray density of the carbon dioxide absorbent gradually increases. In some embodiments, along the horizontal direction of the absorption tower, the difference in spray density between two adjacent groups of carbon dioxide absorbent along the horizontal direction of the absorption tower is independently 0.01-8.5m 3 ·m -2 ·h -1 , for example 0.01m 3 ·m -2 ·h -1 , 0.05m 3 ·m -2 ·h -1 , 0.1m 3 ·m -2 ·h -1 , 0.2m 3 ·m -2 ·h -1 , 0.3m 3 ·m -2 ·h -1 , 0.5m 3 ·m -2 ·h -1 , 0.8m 3 ·m -2 ·h -1 , 1m 3 ·m -2 ·h -1 , 1.3m 3 ·m -2 ·h -1 , 1.6m 3 ·m -2 ·h -1 , 1.8m 3 ·m -2 ·h -1 , 2m 3 ·m -2 ·h -1 , 3m 3 ·m -2 ·h -1 , 4m 3 ·m -2 ·h -1 , 5m 3 ·m -2 ·h -1 、6m 3 ·m -2 ·h -1 , 8.5m 3 ·m -2 ·h -1, or a range consisting of any two of the above values. In some preferred cases, the difference in spray density between two adjacent groups of carbon dioxide absorbents is preferably independently 0.05-3m 3 ·m -2 ·h -1 .

[0063] In the present invention, controlling the difference in spray density between two adjacent groups of carbon dioxide absorbents within the above range, that is, controlling the change value of the spray density within the above range, can better improve the carbon dioxide capture efficiency.

[0064] According to the present invention, in order to gradually increase the spray density of the carbon dioxide absorbent along the horizontal direction of the absorption tower, a plurality of groups of lateral carbon dioxide absorbent outflow sources with different spray densities can be provided in the present invention. As long as the purpose of the present invention can be achieved, the number of lateral carbon dioxide absorbent outflow sources is not particularly limited. In some embodiments, the number of changes in the initial spray density of the carbon dioxide absorbent along the horizontal direction of the absorption tower is recorded as Δn, and Δn is an integer between 2 and 50, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 20, 30, 40, 50, or a range consisting of any two of the above values; in some preferred cases, Δn is an integer between 5 and 20.

[0065] In the present invention, the number of times the spray density of the carbon dioxide absorbent is gradually changed is controlled within the above range, which can better balance the energy consumption and capture efficiency.

[0066] According to the present invention, the spray density of the first group of carbon dioxide absorbents at the inlet end (i.e., the initial spray density) is not particularly limited and can be selected by those skilled in the art as needed. For example, the initial maximum absorption efficiency in the first group of spray assemblies corresponding to conditions such as wind speed and the concentration of the active ingredient in the carbon dioxide absorbent can be selected. Generally, the wind speed is 0.5-3 m / s, the concentration of the active ingredient in the carbon dioxide absorbent is 0.2-12 mol / L, and the initial spray density in the first group of spray assemblies is generally 1-80 m / s. 3 ·m -2 ·h -1 Specifically, the initial spray density in the first group of spray components can be 1m 3 ·m -2 ·h -1 , 3m 3 ·m -2 ·h -1 , 5m 3 ·m -2 ·h -1 、6m 3 ·m -2 ·h -1 , 8m 3 ·m-2 ·h -1 、12m 3 ·m -2 ·h -1 , 20m 3 ·m -2 ·h -1 、30m 3 ·m -2 ·h -1 50m 3 ·m -2 ·h -1 、80m 3 ·m -2 ·h -1 , or a range consisting of any two of the above values.

[0067] According to the present invention, in order to achieve the spray density of each group of carbon dioxide absorbents in the horizontal direction of the absorption tower, multiple points can be set in the wide diameter direction, that is, the sum of the outflow sources in the wide diameter direction is set to achieve the corresponding spray density.

[0068] The term "outflow source in the wide-diameter direction" refers to the outflow points of the carbon dioxide absorbent distributed in the radial or width direction. The outflow points of the carbon dioxide absorbent are arranged in a straight line and continuously along the wide-diameter direction (such as a row of nozzles each flowing out the carbon dioxide absorbent). There is no special limitation on the number of carbon dioxide absorbent outflow points distributed in the wide-diameter direction, as long as the corresponding spray density can be achieved in the end. Generally, the spray density corresponding to each point is the same, that is, the flow rate at each point is evenly distributed.

[0069] According to the present invention, as long as the purpose of the present invention can be achieved, the interval time of intermittently spraying the carbon dioxide absorbent can be selected within a wide range, and is generally selected comprehensively based on the height of the absorption tower, the concentration of the carbon dioxide absorbent, the spray density, and the capture time. In some embodiments, the interval time of intermittently spraying the carbon dioxide absorbent is 10-120s, for example, 10s, 20s, 30s, 40s, 50s, 60s, 70s, 80s, 90s, 100s, 120s, or a range consisting of any two of the above values.

[0070] According to the present invention, in some embodiments, along the vertical direction of the absorption tower, at least m groups of carbon dioxide absorbents of different longitudinal heights intermittently flow out, where m is an integer not less than 2, and preferably m is an integer of 2-7.

[0071] In the present invention, at least two groups of carbon dioxide absorbents with different vertical heights are set to intermittently flow out. The effective ingredients in the carbon dioxide absorbent flowing out of the first group along the vertical direction of the absorption tower are quickly consumed. The rich liquid after the reaction cannot effectively capture the carbon dioxide in the air below the filler when flowing through the bottom of the tower. The carbon dioxide absorbent flowing out later and the rich liquid flowing down from the upper part can still capture the carbon dioxide in the gas together, which can more effectively capture the carbon dioxide in the gas.

[0072] According to the present invention, the intervals of the carbon dioxide absorbent flowing out at different vertical heights may be the same or different. Preferably, the intervals of the carbon dioxide absorbent spraying are the same.

[0073] According to the present invention, optionally, at the initial stage of operation, multiple groups of carbon dioxide absorbers with different longitudinal heights intermittently flow out and work simultaneously. In the middle or late stage, the flow of one or more groups of carbon dioxide absorbers can be closed, and the remaining carbon dioxide absorber groups continue to flow out intermittently until the operation is stopped.

[0074] According to the present invention, in some embodiments, along the vertical direction of the absorption tower, the spray density of the m-1th group of carbon dioxide absorbent is not lower than the spray density of the mth group of carbon dioxide absorbent.

[0075] In the present invention, the spray density of the carbon dioxide absorbent flowing out of the absorption tower in the vertical direction is controlled to gradually decrease, thereby saving energy consumption and more efficiently capturing carbon dioxide in the gas.

[0076] According to the present invention, in some embodiments, along the vertical direction of the absorption tower, the difference between the initial spray density of the m-1 group of carbon dioxide absorbents and the initial spray density of the m group of carbon dioxide absorbents is 0.5-14m 3 ·m -2 ·h -1 , for example 0.5m 3 ·m -2 ·h -1 、1.54m 3 ·m -2 ·h -1 , 2.9m 3 ·m -2 ·h -1 、3.36m 3 ·m -2 ·h -1 、6.65m 3 ·m -2 ·h -1 , 7m 3 ·m -2 ·h -1 , 8m 3 ·m -2 ·h-1 , 9m 3 ·m -2 ·h -1 、10m 3 ·m -2 ·h -1 、12m 3 ·m -2 ·h -1 、14m 3 ·m -2 ·h -1 , or the range of any two of the above values, preferably 1-9m 3 ·m -2 ·h -1 .

[0077] According to the present invention, as long as the purpose of the present invention can be achieved, the source of the carbon dioxide-containing gas is not particularly limited. In some embodiments, the carbon dioxide-containing gas includes air and / or industrial exhaust gas.

[0078] DAC technology uses physical or chemical methods to absorb carbon dioxide from the atmosphere, then releases high-purity carbon dioxide through heating, electrochemical reactions, or pressure reduction for storage or reuse. While capturing carbon dioxide from air is used as an example to illustrate the advantages of this invention, it is not intended to limit the scope of this invention.

[0079] According to the present invention, the carbon dioxide absorbent refers to a liquid solution capable of reacting with carbon dioxide, which is any solution in the art that can capture carbon dioxide in gas. In some embodiments, the carbon dioxide absorbent includes an alkaline aqueous solution; the alkaline aqueous solution refers to a solution containing water that can release hydroxide ions, and its concentration can be selected in a wide range, for example, the concentration of the alkaline aqueous solution is 0.2-12 mol / L.

[0080] Examples of the alkaline solution used in the present invention include aqueous sodium hydroxide solution, aqueous potassium hydroxide solution, aqueous ammonia solution, and the like.

[0081] According to the present invention, in some embodiments, the method further includes: circulating all or part of the contacted material as a carbon dioxide absorbent for intermittent spraying, preferably circulating all of it as a carbon dioxide absorbent for intermittent spraying, for example, using a batch of carbon dioxide absorbent to capture carbon dioxide in the carbon dioxide-containing gas, the carbon dioxide-containing gas flowing horizontally through the absorption tower is in contact with the carbon dioxide absorbent intermittently flowing out in the direction of gravity, the rich liquid after contact is mixed with the remaining carbon dioxide absorbent and continues to contact the carbon dioxide-containing gas until all the effective ingredients in the carbon dioxide absorbent react with the carbon dioxide.

[0082] In the present invention, the carbon dioxide adsorbent after capturing carbon dioxide serves as the contact material, and may contain effective components that can adsorb carbon dioxide. It is contacted with the carbon dioxide-containing gas together with the remaining carbon dioxide adsorbent to capture carbon dioxide. This not only saves carbon dioxide adsorbent material, but also achieves a high capture efficiency for carbon dioxide using the method of the present invention.

[0083] According to the present invention, in some embodiments, the method for capturing carbon dioxide provided in the second aspect of the present invention can be performed using the system for capturing carbon dioxide provided in the first aspect of the present invention.

[0084] According to the present invention, in some embodiments, Figure 2-Figure 5 As shown, a system for capturing carbon dioxide is provided, the system comprising:

[0085] The absorption tower 1 is in the shape of a rectangular parallelepiped and has an air inlet 2 and an air outlet 3. The air inlet 2 and the air outlet 3 are arranged opposite to each other along the horizontal direction of the absorption tower 1. The left vertical side of the absorption tower 1 is the air inlet 2. The right side of the absorption tower 1 is uniformly contracted in the horizontal direction to form a prism-shaped air outlet 3 with a top surface size that can accommodate the size of the fan 4.

[0086] Three groups of gas absorption components are arranged in the absorption tower 1 at different longitudinal heights along the vertical direction of the absorption tower 1. Each group of gas absorption components includes a liquid supply component, a spray component 5 and a packing layer 7. The liquid supply component is connected to the spray component 5, and the packing layer 7 is located below the corresponding spray component 5. Multiple nozzles evenly distributed in the transverse direction and multiple nozzles evenly distributed in the width direction are used as the spray component 5.

[0087] A speed control assembly includes a flow control valve provided on each nozzle to control the intermittent spraying of the carbon dioxide absorbent and to control the spray density of the carbon dioxide absorbent flowing out of the spray element 5 to gradually increase along the horizontal direction of the absorption tower 1;

[0088] A fan 4 is provided at the air outlet 3;

[0089] The carbon dioxide absorbent container 8 is arranged at the bottom of the absorption tower 1 .

[0090] According to the present invention, in some embodiments, a method for capturing carbon dioxide is provided. Figure 2-Figure 5 The system shown in FIG. 1 includes the following steps:

[0091] The KOH aqueous solution is delivered from the carbon dioxide absorbent container 8 through the liquid supply components in each gas absorption assembly to the corresponding spray component inlet pipe 6. The air is then delivered to the absorption tower 1 through the air inlet 2 by the fan 4 at the air outlet 3. The air contacts the KOH aqueous solution and captures carbon dioxide before being delivered to the outside of the system.

[0092] In the three groups of gas absorption components: the spray density of the multiple groups of KOH aqueous solutions intermittently sprayed from the air inlet 2 to the air outlet 3 by the multiple nozzles evenly distributed in the transverse direction is set from small to large, and the spray density of the KOH aqueous solutions intermittently sprayed by the multiple nozzles evenly distributed in the width direction in the three groups of gas absorption components is kept consistent;

[0093] The interval time of spraying the KOH aqueous solution from the nozzle is 10-120 seconds. When the KOH aqueous solution is sprayed out of each group of gas absorption components in the absorption tower 1, the KOH aqueous solution passes through the corresponding packing layer 7 to react with carbon dioxide in the air to capture carbon dioxide in the air. After the nozzle stops spraying for 10-120 seconds, it continues to spray out the KOH aqueous solution according to the above steps to capture carbon dioxide in the air. This start and stop process is repeated. At this time, each packing layer 7 contains the KOH aqueous solution and the potassium carbonate solution after reacting with carbon dioxide. The KOH aqueous solution in each packing layer 7 continues to react with carbon dioxide in the air during the gradual decline process and finally flows into the carbon dioxide absorbent holding device 8 at the bottom of the absorption tower 1 and mixes with the remaining KOH aqueous solution. After that, it is circulated through each liquid supply part to the corresponding spray part inlet pipeline 6 to continue capturing carbon dioxide in the air until the KOH aqueous solution in the carbon dioxide absorbent holding device 8 is completely converted into K2CO3 aqueous solution.

[0094] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0095] Example 1-1

[0096] Reference Figure 2-Figure 5 , the annual air capture carbon dioxide capacity is 3,000 tons. The rectangular absorption tower 1 is 20 meters high and 20 meters wide. Along the vertical direction of the absorption tower 1, three groups of gas absorption components are arranged in the absorption tower 1; the spray parts 5 in the three groups of gas absorption components all adopt 10 groups of nozzles evenly distributed in the transverse direction and 20 nozzles evenly distributed in the width direction; the transverse depth of each packing layer 7 is 10 meters; along the vertical direction of the absorption tower 1, the first group of gas absorption components is at the top of the absorption tower 1, the second group of gas absorption components is 12 meters from the top, and the third group of gas absorption components is 16 meters from the top; the left vertical side of the absorption tower 1 is the air inlet 2; the right side of the absorption tower 1 is evenly contracted in the horizontal direction to form a prism-shaped air outlet 3 of the size of the top surface that can accommodate the size of the fan 4, and the fan 4 is arranged at the air outlet 3;

[0097] A batch of KOH aqueous solution with a concentration of 7.5 mol / L is delivered from the carbon dioxide absorbent container 8 through the liquid supply components in each gas absorption assembly to the corresponding spray component inlet pipeline 6. The air is then delivered to the absorption tower 1 through the air inlet 2 by the fan 4 at the air outlet 3. The air contacts the KOH aqueous solution and captures carbon dioxide before being delivered to the outside of the system. The wind speed at the air inlet is 0.9 m / s, and the wind speed at the air outlet is 1.4 m / s.

[0098] In the first gas absorption assembly, 10 groups of nozzles evenly distributed laterally spray intermittently from the air inlet 2 to the air outlet 3, and the spray density of 10 groups of KOH aqueous solutions is 8.00m 3 ·m -2 ·h -1 、8.15m 3 ·m -2 ·h -1 , 8.30m 3 ·m -2 ·h -1 、8.45m 3 ·m -2 ·h -1 、8.60m 3 ·m -2 ·h -1 , 8.75m 3 ·m -2 ·h -1 、8.90m 3 ·m -2 ·h -1 、9.05m 3 ·m -2 ·h -1 、9.15m 3 ·m -2 ·h -1 , 9.30m 3 ·m -2 ·h -1 Setting from small to large;

[0099] In the second gas absorption component, 10 groups of nozzles evenly distributed laterally spray intermittently from the air inlet 2 to the air outlet 3, and the spray density of 10 groups of KOH aqueous solutions is 2.65m 3 ·m -2 ·h -1 , 2.75m 3 ·m -2 ·h -1 , 2.85m 3 ·m -2 ·h -1 , 2.95m 3 ·m -2 ·h-1 3.05m 3 ·m -2 ·h -1 3.15m 3 ·m -2 ·h -1 3.25m 3 ·m -2 ·h -1 3.35m 3 ·m -2 ·h -1 、3.45m 3 ·m -2 ·h -1 、3.55m 3 ·m -2 ·h -1 Setting from small to large;

[0100] In the third gas absorption component, 10 groups of nozzles evenly distributed laterally spray intermittently from the air inlet 2 to the air outlet 3, and the spray density of 10 groups of KOH aqueous solutions is 0.1m 3 ·m -2 ·h -1 , 0.2m 3 ·m -2 ·h -1 , 0.3m 3 ·m -2 ·h -1 , 0.4m 3 ·m -2 ·h -1 , 0.5m 3 ·m -2 ·h -1 , 0.6m 3 ·m -2 ·h -1 , 0.7m 3 ·m -2 ·h -1 , 0.8m 3 ·m -2 ·h -1 , 0.9m 3 ·m -2 ·h -1 , 1.0m 3 ·m -2 ·h -1 Setting from small to large;

[0101] The spray density of the KOH aqueous solution intermittently sprayed by 20 nozzles uniformly distributed in the width direction in the three groups of gas absorption components remains consistent, and the spray density of each corresponds to the spray density of 10 groups of KOH aqueous solutions intermittently sprayed from the direction of the air inlet 2 to the air outlet 3 by 10 groups of nozzles uniformly distributed in the transverse direction;

[0102] The interval time for spraying the KOH aqueous solution from each group of gas absorption components is 45 seconds. When the KOH aqueous solution is sprayed out from each group of gas absorption components in the absorption tower 1, the KOH aqueous solution passes through the corresponding packing layer 7 to react with carbon dioxide in the air to capture carbon dioxide in the air. After the nozzle stops spraying for 45 seconds, it continues to spray out the KOH aqueous solution according to the above steps to capture carbon dioxide in the air, and this start and stop process is repeated. At this time, each packing layer 7 contains the KOH aqueous solution and the potassium carbonate solution after reacting with carbon dioxide. The KOH aqueous solution in each packing layer 7 continues to react with carbon dioxide in the air during the gradual decline process, and finally flows into the carbon dioxide absorbent holding device 8 at the bottom of the absorption tower 1, mixes with the remaining KOH aqueous solution, and is circulated through each liquid supply component to the corresponding spray component inlet pipeline 6 to continue capturing carbon dioxide in the air until the KOH aqueous solution in the carbon dioxide absorbent holding device 8 is completely converted into K2CO3 aqueous solution.

[0103] After 3 days of operation, the second and third gas absorption components were stopped, and the first group of gas absorption components continued to work intermittently until the KOH aqueous solution was completely converted into the K2CO3 aqueous solution.

[0104] After 120 hours of operation, all the KOH aqueous solution was converted into K2CO3 aqueous solution, and the power consumption was 12160.8kW·h.

[0105] Compared with Comparative Example 1, the processing time is shortened by 16.7% and the power consumption is reduced by 18.7%.

[0106] Example 1-2

[0107] The method of Example 1 is as follows, except that:

[0108] The spray density of the 10 groups of KOH aqueous solutions intermittently sprayed from the direction of the air inlet 2 to the direction of the air outlet 3 by the 10 groups of nozzles uniformly distributed laterally in the first group of gas absorption components is 9.21m 3 ·m -2 ·h -1 9.22m 3 ·m -2 ·h -1 9.23m 3 ·m -2 ·h -1 9.24m 3·m -2 ·h -1 、9.25m 3 ·m -2 ·h -1 、9.26m 3 ·m -2 ·h -1 、9.27m 3 ·m -2 ·h -1 、9.28m 3 ·m -2 ·h -1 、9.29m 3 ·m -2 ·h -1 , 9.30m 3 ·m -2 ·h -1 Setting from small to large;

[0109] The spray density of the 10 groups of KOH aqueous solutions intermittently sprayed from the direction of the air inlet 2 to the direction of the air outlet 3 by the 10 groups of nozzles uniformly distributed laterally in the second group of gas absorption components is 3.46m 3 ·m -2 ·h -1 3.47m 3 ·m -2 ·h -1 、3.48m 3 ·m -2 ·h -1 、3.49m 3 ·m -2 ·h -1 , 3.5m 3 ·m -2 ·h -1 、3.51m 3 ·m -2 ·h -1 、3.52m 3 ·m -2 ·h -1 、3.53m 3 ·m -2 ·h -1 、3.54m 3 ·m -2 ·h -1 、3.55m 3 ·m -2 ·h -1 Setting from small to large;

[0110] In the third gas absorption component, 10 groups of nozzles evenly distributed laterally spray intermittently from the air inlet 2 to the air outlet 3, and the spray density of 10 groups of KOH aqueous solutions is 0.91m 3 ·m -2 ·h -1 、0.92m 3 ·m -2 ·h -1 、0.93m 3 ·m -2 ·h -1 、0.94m 3 ·m -2 ·h -1 , 0.95m 3 ·m -2 ·h -1 、0.96m 3 ·m -2 ·h -1 、0.97m 3 ·m -2 ·h -1 、0.98m 3 ·m -2 ·h -1 , 0.99m 3 ·m -2 ·h -1 、1.00m 3 ·m -2 ·h -1 Setting from small to large;

[0111] After 132 hours of operation, all the KOH aqueous solution was converted into K2CO3 aqueous solution, and the power consumption was 13492.0kW·h.

[0112] Compared with Comparative Example 1, the processing time is shortened by 8.3% and the power consumption is reduced by 9.8%.

[0113] Examples 1-3

[0114] The method of Example 1-1 is as follows, except that:

[0115] The first group of gas absorption components is at the top of the absorption tower 1, the second group of gas absorption components is 10 meters from the top, and the third group of gas absorption components is 14 meters from the top.

[0116] After 128 days of operation, all the KOH aqueous solution was converted into K2CO3 aqueous solution, and the electricity consumption was 13133.0kW·h.

[0117] Compared with Comparative Example 1, the processing time is shortened by 11.1% and the power consumption is reduced by 12.2%.

[0118] Comparative Example 1

[0119] According to the existing process, the same batch and the same KOH aqueous solution in Example 1-1 were used to capture carbon dioxide in the air. Specifically, the method of Example 1-1 was followed, except that:

[0120] In the first gas absorption assembly, 10 groups of nozzles evenly distributed laterally spray intermittently from the air inlet 2 to the air outlet 3, and the spray density of the 10 groups of KOH aqueous solutions is 9.3m 3 ·m -2 ·h -1 ;

[0121] In the second gas absorption component, 10 groups of nozzles evenly distributed laterally spray intermittently from the air inlet 2 to the air outlet 3, and the spray density of the 10 groups of KOH aqueous solutions is 3.55m 3 ·m -2 ·h -1 Setting from small to large;

[0122] In the third group of gas absorption components: 8 nozzles evenly distributed laterally spray 8 groups of KOH aqueous solutions from the direction of air inlet 2 to the direction of air outlet 3, with the spray density of 1.0m 3 ·m -2 ·h -1 Setting from small to large;

[0123] During operation, the three groups of gas absorption components work continuously and uninterruptedly.

[0124] After 144 days of operation, all the KOH aqueous solution was converted into K2CO3 aqueous solution, and the electricity consumption was 14957.9kW·h.

[0125] Example 2-1

[0126] The method of Example 1-1 is as follows, except that:

[0127] The rectangular absorption tower 1, which captures 2,000 tons of carbon dioxide annually, is 16 meters high and 16 meters wide. Two sets of gas absorption assemblies are installed vertically inside the absorption tower 1. The spray elements 5 in both sets of gas absorption assemblies use eight sets of nozzles evenly distributed laterally and 16 nozzles evenly distributed widthwise. Each packing layer 7 has a horizontal depth of 9 meters. Vertically, the first set of gas absorption assemblies is at the top of the absorption tower 1, and the second set is 10 meters from the top.

[0128] A batch of 8 mol / L KOH aqueous solution is delivered from the carbon dioxide absorbent container 8 through the liquid supply components in each gas absorption assembly to the corresponding spray component inlet pipe 6; the wind speed at the air inlet end is 0.9 m / s, and the wind speed at the air outlet end is 1.3 m / s;

[0129] In the first gas absorption component, 8 groups of nozzles evenly distributed laterally spray intermittently from the air inlet 2 to the air outlet 3. The spray density of the 8 groups of KOH aqueous solutions is 8.15m 3 ·m -2 ·h -1 , 8.2m 3 ·m -2 ·h -1 , 8.25m 3 ·m -2 ·h -1 , 8.3m 3 ·m -2 ·h -1 、8.35m 3 ·m -2 ·h -1 , 8.4m 3 ·m -2 ·h -1 、8.45m 3 ·m -2 ·h -1 , 8.5m 3 ·m -2 ·h -1 Setting from small to large;

[0130] In the second gas absorption component, 8 groups of nozzles evenly distributed laterally spray intermittently from the air inlet 2 to the air outlet 3, and the spray density of the 8 groups of KOH aqueous solutions is 1.5m 3 ·m -2 ·h -1 , 1.6m 3 ·m -2 ·h -1 , 1.7m 3 ·m -2 ·h -1 , 1.8m 3 ·m -2 ·h -1 , 1.9m 3 ·m -2 ·h -1 , 2m 3 ·m -2 ·h -1 , 2.1m 3 ·m -2 ·h -1 , 2.2m 3 ·m -2 ·h -1 Setting from small to large;

[0131] The spray density of the KOH aqueous solution intermittently sprayed by the 16 nozzles uniformly distributed in the width direction in the two groups of gas absorption components remains consistent, and the spray density of each corresponds to the spray density of the 8 groups of KOH aqueous solutions intermittently sprayed by the 8 groups of nozzles uniformly distributed in the transverse direction from the air inlet 2 to the air outlet 3;

[0132] The interval time for spraying KOH aqueous solution from each group of gas absorption components is 40s;

[0133] After 3 days of operation, the second set of gas absorption components was stopped, and the first set of gas absorption components continued to work intermittently until the KOH aqueous solution was completely converted into the K2CO3 aqueous solution.

[0134] After 120 hours of operation, all the KOH aqueous solution was converted into K2CO3 aqueous solution, and the power consumption was 9312kW·h.

[0135] Compared with Comparative Example 2, the processing time is shortened by 16.7% and the power consumption is reduced by 19%.

[0136] Example 2-2

[0137] The method of Example 2-1 is followed, except that:

[0138] Along the vertical direction of the absorption tower 1, four groups of gas absorption components are arranged in the absorption tower 1; the spraying parts 5 in the four groups of gas absorption components all use 8 groups of nozzles evenly distributed in the transverse direction and 16 nozzles evenly distributed in the width direction; the transverse depth of each packing layer 7 is 9 meters; along the vertical direction of the absorption tower 1, the first group of gas absorption components is at the top of the absorption tower 1, the second group of gas absorption components is 8 meters from the top, the third group of gas absorption components is 12 meters from the top; the fourth group of gas absorption components is 15 meters from the top. In the first group of gas absorption components: the 8 groups of nozzles evenly distributed in the transverse direction spray out 8 groups of KOH aqueous solutions intermittently from the direction of the air inlet 2 to the direction of the air outlet 3, and the spray density is 6.15m 3 ·m -2 ·h -1 , 6.2m 3 ·m -2 ·h -1 、6.25m 3 ·m -2 ·h -1 、6.3m 3 ·m -2 ·h -1 、6.35m 3 ·m -2 ·h -1 、6.4m 3 ·m -2 ·h -1 、6.45m 3·m -2 ·h -1 、6.5m 3 ·m -2 ·h -1 Setting from small to large;

[0139] In the second gas absorption component, 8 groups of nozzles evenly distributed laterally spray intermittently from the air inlet 2 to the air outlet 3, and the spray density of 8 groups of KOH aqueous solutions is 4.15m 3 ·m -2 ·h -1 , 4.2m 3 ·m -2 ·h -1 4.25m 3 ·m -2 ·h -1 , 4.3m 3 ·m -2 ·h -1 , 4.35m 3 ·m -2 ·h -1 4.4m 3 ·m -2 ·h -1 4.45m 3 ·m -2 ·h -1 , 4.5m 3 ·m -2 ·h -1 Setting from small to large;

[0140] In the third gas absorption component, 8 groups of nozzles evenly distributed laterally spray intermittently from the air inlet 2 to the air outlet 3, and the spray density of the 8 groups of KOH aqueous solutions is 1.15m 3 ·m -2 ·h -1 , 1.2m 3 ·m -2 ·h -1 , 1.25m 3 ·m -2 ·h -1 , 1.3m 3 ·m -2 ·h -1 , 1.35m 3 ·m -2 ·h -1 , 1.4m 3 ·m -2 ·h -1 , 1.45m 3 ·m -2 ·h -1 , 1.5m3 ·m -2 ·h -1 Setting from small to large;

[0141] In the fourth gas absorption component, eight groups of nozzles evenly distributed laterally spray intermittently from the air inlet 2 to the air outlet 3, and the spray density of the eight groups of KOH aqueous solutions is 0.15m 3 ·m -2 ·h -1 , 0.2m 3 ·m -2 ·h -1 , 0.25m 3 ·m -2 ·h -1 , 0.3m 3 ·m -2 ·h -1 , 0.35m 3 ·m -2 ·h -1 , 0.4m 3 ·m -2 ·h -1 , 0.45m 3 ·m -2 ·h -1 , 0.5m 3 ·m -2 ·h -1 Setting from small to large;

[0142] The spray density of the KOH aqueous solution intermittently sprayed by the 16 nozzles uniformly distributed in the width direction in the four groups of gas absorption components remains consistent, and the spray density of each corresponds to the spray density of the 8 groups of KOH aqueous solutions intermittently sprayed from the direction of the air inlet 2 to the air outlet 3 by the 8 groups of nozzles uniformly distributed in the transverse direction;

[0143] The interval time for spraying the KOH aqueous solution from each group of gas absorption components is 40s;

[0144] After 3 days of operation, the second, third and fourth groups of gas absorption components are stopped, and the first group of gas absorption components continues to work intermittently until the KOH aqueous solution is completely converted into the K2CO3 aqueous solution.

[0145] After 136 hours of operation, all the KOH aqueous solution was converted into K2CO3 aqueous solution, and the power consumption was 10829.3kW·h.

[0146] Compared with Comparative Example 2, the processing time is shortened by 5% and the power consumption is reduced by 5.8%.

[0147] Example 2-3

[0148] The method of Example 2-1 is followed, except that:

[0149] The first group of gas absorption components is at the top of the absorption tower 1, and the second group of gas absorption components is 6 meters away from the top.

[0150] After 128 hours of operation, all the KOH aqueous solution was converted into K2CO3 aqueous solution, and the power consumption was 10369.4kW·h.

[0151] Compared with Comparative Example 2, the processing time is shortened by 11.1% and the power consumption is reduced by 9.8%.

[0152] Comparative Example 2

[0153] According to the existing process, the same batch and the same KOH aqueous solution in Example 2-1 were used to capture carbon dioxide from the air. Specifically, the method of Example 2-1 was followed, except that:

[0154] In the first set of gas absorption components: the eight groups of nozzles evenly distributed laterally spray from the air inlet 2 to the air outlet 3, and the spray density of the eight groups of KOH aqueous solutions is 8.3m 3 ·m -2 ·h -1 ;

[0155] The second set of gas absorption components does not work;

[0156] During operation, the first group of gas absorption components works continuously and uninterruptedly.

[0157] After 144 hours of operation, all the KOH aqueous solution was converted into K2CO3 aqueous solution, and the power consumption was 11496kW·h.

[0158] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A system for capturing carbon dioxide, characterized in that: The system includes: An absorption tower (1), the absorption tower (1) having an air inlet (2) and an air outlet (3), the air inlet (2) and the air outlet (3) being arranged opposite to each other in a transverse direction of the absorption tower (1); A gas absorption component is provided in the absorption tower (1), and comprises a liquid supply component and a spray component (5). The liquid supply component is in communication with the spray component (5) and is used to provide a carbon dioxide absorbent to flow out of the spray component (5) in a gravity direction to contact with the gas containing carbon dioxide to capture carbon dioxide; A speed control component, the speed control component includes a spray control component arranged on the spray component (5), and optionally a liquid supply control component arranged on the liquid supply component, for controlling the intermittent spraying of the carbon dioxide absorbent along the direction of gravity, and controlling the spray density of the carbon dioxide absorbent flowing out of the spray component (5) to gradually increase along the horizontal direction of the absorption tower (1).

2. The system according to claim 1, wherein: The gas absorption component further comprises a packing layer (7), wherein the packing layer (7) is located below the corresponding spraying element (5); and / or, at least m groups of gas absorption components with different longitudinal heights are arranged along the vertical direction of the absorption tower (1), where m is an integer not less than 2, and preferably m is an integer from 2 to 7; and / or The spraying part (5) in the gas absorption assembly comprises a plurality of spray heads arranged in a matrix along the cross section of the absorption tower (1).

3. The system according to claim 2, wherein: m is an integer from 2 to 7; and / or, a group of gas absorption components is arranged at the top of the absorption tower (1); and / or, when m is 2, along the vertical direction of the absorption tower (1), the distance Δh between two groups of gas absorption components is ≥ 0.5*h, where h is the height of the absorption tower (1); when m is an integer greater than 2, along the vertical direction of the absorption tower (1), the distance between two adjacent groups of gas absorption components is sequentially recorded as Δh1 to Δh i , i is an integer not less than 2, and Δh1 to Δh i The values ​​of are successively reduced, Δh1≥0.5*h, where h is the height of the absorption tower (1); And / or, the speed control component is further used to control the spraying density of the carbon dioxide absorbent in the m-1th group of spraying parts (5) to be not lower than the spraying density of the carbon dioxide absorbent in the mth group of spraying parts (5); And / or, the spray control component includes a flow control valve arranged on the spray head.

4. The system according to claim 1, wherein: The cross section of the absorption tower (1) is square or circular; And / or, the air inlet (2) is provided at a part of the side inlet of the absorption tower (1); And / or, the air outlet (3) is in a contraction shape.

5. The system according to any one of claims 1 to 4, wherein: The system further comprises: a gas conveying device, the gas conveying device being arranged at the gas inlet (2) and / or the gas outlet (3), for conveying the gas containing carbon dioxide into the absorption tower (1) through the gas inlet (2), performing the contact to capture carbon dioxide, and then continuing to convey the gas out of the system; preferably, the gas conveying device comprises a fan (4) arranged at the gas outlet (3); And / or, the system further comprises a carbon dioxide absorbent containing device (8), wherein the carbon dioxide absorbent containing device (8) is arranged at the bottom of the absorption tower (1) for containing the carbon dioxide absorbent and the carbon dioxide absorbent after capturing carbon dioxide.

6. A method for capturing carbon dioxide, characterized in that: The method includes: The carbon dioxide-containing gas flowing horizontally through the absorption tower comes into contact with the carbon dioxide absorbent flowing out intermittently in the direction of gravity; Wherein, the spraying density of the carbon dioxide absorbent gradually increases along the horizontal direction of the absorption tower.

7. The method according to claim 6, wherein: Along the horizontal direction of the absorption tower, the difference between the initial spray density of the carbon dioxide absorbent and the final spray density of the carbon dioxide absorbent is 0.01-17m 3 ·m -2 ·h -1 , preferably 0.05-5m 3 ·m -2 ·h -1 ; and / or, along the horizontal direction of the absorption tower, the difference in spray density between two adjacent groups of carbon dioxide absorbents is independently 0.01-8.5 m 3 ·m -2 ·h -1 , preferably 0.05-3m 3 ·m -2 ·h -1 .

8. The method according to claim 6, wherein: The number of times the initial spray density of the carbon dioxide absorbent changes along the horizontal direction of the absorption tower is recorded as Δn, where Δn is an integer between 2 and 50, preferably an integer between 5 and 20; And / or, the interval time of intermittent spraying of the carbon dioxide absorbent is 10-120s.

9. The method according to claim 6, wherein: At least m groups of carbon dioxide absorbents of different longitudinal heights are intermittently flowed out along the vertical direction of the absorption tower, where m is an integer not less than 2, and preferably m is an integer from 2 to 7; Preferably, along the vertical direction of the absorption tower, the spray density of the m-1th group of carbon dioxide absorbent is not lower than the spray density of the mth group of carbon dioxide absorbent; More preferably, along the vertical direction of the absorption tower, the difference between the initial spray density of the m-1th group of carbon dioxide absorbent and the initial spray density of the mth group of carbon dioxide absorbent is 0.5-14m 3 ·m -2 ·h -1 , preferably 1-9m 3 ·m -2 ·h -1 .

10. The method according to any one of claims 6 to 9, wherein: The carbon dioxide-containing gas includes air and / or industrial tail gas; and / or, the carbon dioxide absorbent comprises an alkaline aqueous solution, preferably the concentration of the alkaline aqueous solution is 0.2-12 mol / L; And / or, the method further comprises: recycling all or part of the contacted material as a carbon dioxide absorbent to perform the intermittent spraying.

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