Absorption apparatus for carbon dioxide in flue gas, and flue gas purification apparatus and control method therefor

Abstract

The present disclosure provides an absorption apparatus for carbon dioxide in flue gas, and a flue gas purification apparatus and a control method therefor. The absorption apparatus for carbon dioxide in flue gas comprises: an absorption tower. The absorption tower is provided with a mounting space and an inlet and an outlet which are communicated with the mounting space. The mounting space comprises a pre-washing section, an absorption section, a cooling section, a spraying section, and a packing section. An organic amine solution is provided in the absorption section. The inlet is communicated with the pre-washing section. The absorption section is arranged above the pre-washing section. The cooling section is arranged above the absorption section. The spraying section is arranged above the cooling section. The packing section is arranged above the spraying section and is communicated with the outlet. Flue gas flows in a direction from the pre-washing section to the packing section. The technical solution of the present disclosure effectively solves the problem in the related art of the high amine concentration in flue gas discharged from absorption towers.

Description

Absorption devices for carbon dioxide in flue gas, flue gas purification devices and their control methods

[0001] Cross-reference to related applications

[0002] This disclosure is based on and claims priority to Chinese Patent Application No. 202410916602.5, filed on July 9, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to the field of flue gas treatment equipment technology, and more specifically, to a device for absorbing carbon dioxide in flue gas, a flue gas purification device, and a control method thereof. Background Technology

[0004] When using chemical absorption to capture carbon dioxide, the organic amine solution in the absorption tower is highly volatile. As a result, the organic amine solution will be carried out with the flow of flue gas, which is called amine escape. This leads to a high amine concentration at the outlet of the absorption tower, which also increases the loss of organic amine solution and increases the cost of carbon capture.

[0005] In related technologies, the concentration of emitted organic amines can be controlled by washing the flue gas with water, thereby controlling amine escape. Although the concentration of amines in the emitted flue gas is reduced after washing, it is still a relatively high value, exceeding the relevant emission standards. Summary of the Invention

[0006] The main objective of this disclosure is to provide a carbon dioxide absorption device, a flue gas purification device, and a control method thereof to solve the problem of high amine concentration in the flue gas emitted from absorption towers in related technologies.

[0007] To achieve the above objectives, according to a first aspect of this disclosure, an absorption device for carbon dioxide in flue gas is provided, comprising: an absorption tower, wherein an installation space is provided within the absorption tower and an inlet and an outlet communicating with the installation space, the installation space including a pre-washing section, an absorption section, a cooling section, a spray section, and a packing section, wherein an organic amine solution is provided within the absorption section; wherein the inlet is communicating with the pre-washing section, the absorption section is positioned above the pre-washing section, the cooling section is positioned above the absorption section, the spray section is positioned above the cooling section, the packing section is positioned above the spray section and communicates with the outlet, and the flue gas flows from the pre-washing section to the packing section.

[0008] In some embodiments, the cooling section includes a dry packing layer, and the packing section includes a wet packing layer.

[0009] In some embodiments, the carbon dioxide absorption device in flue gas further includes a spray structure and a first heat exchanger. The spray structure is disposed in the spray section. The absorption tower includes a first liquid inlet and a first liquid outlet disposed at intervals in the spray section. A first end of the first heat exchanger is connected to the first liquid outlet, a second end of the first heat exchanger is connected to the first liquid inlet, and the first liquid inlet is connected to the spray structure.

[0010] According to a second aspect of this disclosure, a flue gas purification device is provided, including a device for absorbing carbon dioxide in flue gas and a regeneration tower connected to the device for absorbing carbon dioxide in flue gas, wherein the device for absorbing carbon dioxide in flue gas is the aforementioned device for absorbing carbon dioxide in flue gas.

[0011] In some embodiments, the flue gas purification device further includes a first connecting pipeline, a second heat exchanger, and a first branch pipeline. The regeneration tower has a second liquid inlet and a third liquid inlet spaced apart. The first end of the first connecting pipeline is connected to the bottom of the absorption section of the carbon dioxide absorption device in the flue gas. The first end of the second heat exchanger is connected to the second end of the first connecting pipeline. The second end of the second heat exchanger is connected to the second liquid inlet. The first end of the first branch pipeline is connected to the second end of the first connecting pipeline. The second end of the first branch pipeline is connected to the third liquid inlet.

[0012] In some embodiments, the flue gas purification device further includes a second connecting pipeline, a third heat exchanger, a second branch pipeline, and a third connecting pipeline. The third heat exchanger has a fourth liquid inlet and a fifth liquid inlet spaced apart. The third heat exchanger also includes a second liquid outlet. The first end of the second connecting pipeline is connected to the top of the regeneration tower, and the second end of the second connecting pipeline is connected to the fourth liquid inlet. The first ends of the second branch pipeline and the first ends of the first branch pipeline are both connected to the second ends of the first connecting pipeline through the third connecting pipeline. The second end of the second branch pipeline is connected to the fifth liquid inlet, and the second liquid outlet is connected to the packing section.

[0013] In some embodiments, the flue gas purification device further includes a regenerated gas separator and a fourth connecting pipeline, a second liquid outlet is connected to the regenerated gas separator, the regenerated gas separator has a third liquid outlet, the absorption tower has a sixth liquid inlet disposed at the packing section, a first end of the fourth connecting pipeline is connected to the third liquid outlet, and a second end of the fourth connecting pipeline is connected to the sixth liquid inlet.

[0014] In some embodiments, the flue gas purification device further includes a fifth connecting pipeline, and the absorption tower also has a fourth liquid outlet disposed at the packing section. The first end of the fifth connecting pipeline is connected to the fourth liquid outlet, the second end of the fifth connecting pipeline is connected to the sixth liquid inlet, and the second end of the fourth connecting pipeline is connected to the middle part of the fifth connecting pipeline.

[0015] In some embodiments, the flue gas purification device further includes a third branch line, the regeneration tower has a seventh liquid inlet, the first end of the third branch line is connected to the middle of the fifth connecting line and is located between the fourth liquid outlet and the second end of the fourth connecting line, and the second end of the third branch line is connected to the seventh liquid inlet.

[0016] According to a third aspect of this disclosure, a control method for a flue gas purification device is provided, wherein the control method for the flue gas purification device includes:

[0017] The on / off state of the first branch pipeline and the first connecting pipeline is controlled according to the flow rate of the first branch pipeline.

[0018] The on / off status of the first branch pipeline and the first connecting pipeline, as well as the on / off status of the second branch pipeline and the first connecting pipeline, are controlled based on the sum of the flow rates of the first branch pipeline and the second branch pipeline.

[0019] In some embodiments, the step of controlling the connection between the first branch pipeline and the first connecting pipeline based on the flow rate of the first branch pipeline includes:

[0020] When the flow rate of the first branch pipeline exceeds the first threshold, the connection between the first branch pipeline and the first connecting pipeline is disconnected. The first threshold is greater than or equal to one-fifth of the sum of the flow rates of the first branch pipeline and the second branch pipeline and less than or equal to three-fifths of the sum of the flow rates of the first branch pipeline and the second branch pipeline.

[0021] In some embodiments, the step of simultaneously controlling the connection between the first branch pipeline and the first connecting pipeline and the connection between the second branch pipeline and the first connecting pipeline based on the sum of the flow rates of the first branch pipeline and the second branch pipeline includes:

[0022] When the sum of the flow rate of the first branch pipeline and the flow rate of the second branch pipeline exceeds the second threshold, the connection between the first branch pipeline and the first connecting pipeline and the connection between the second branch pipeline and the first connecting pipeline are cut off, wherein the second threshold is greater than or equal to one-eighth of the flow rate of the first connecting pipeline.

[0023] Using the technical solution disclosed herein, the absorption tower is equipped with an installation space, an inlet, and an outlet, both of which are connected to the installation space. The installation space includes a pre-washing section, an absorption section, a cooling section, a spray section, and a packing section arranged sequentially. An organic amine solution is placed within the absorption section. The inlet is connected to the pre-washing section, and the outlet is connected to the packing section. The flue gas flows from the pre-washing section to the packing section. Through this arrangement, the flue gas can enter the installation space through the inlet and sequentially pass through the pre-washing section, absorption section, cooling section, spray section, and packing section before exiting through the outlet. The pre-washing section pre-treats the flue gas, removing trace amounts of gypsum and other impurities. The organic amine solution in the absorption section absorbs carbon dioxide from the flue gas. The cooling section lowers the temperature of the flue gas. The spray section sprays liquid, which directly contacts the flue gas, absorbing organic amine molecules and further reducing the concentration of amines in the emitted flue gas. The packing section can further reduce the content of impurities such as organic amine molecules and aerosols in the flue gas, thereby reducing the concentration of amines in the emitted flue gas. Therefore, the technical solution disclosed herein effectively solves the problem of high amine concentrations in the flue gas emitted from absorption towers in related technologies. Attached Figure Description

[0024] The accompanying drawings, which form part of this disclosure, are used to provide a further understanding of this disclosure. The illustrative embodiments of this disclosure and their descriptions are used to explain this disclosure and do not constitute an undue limitation of this disclosure. In the drawings:

[0025] Figure 1 shows a schematic diagram of an embodiment of the flue gas purification device according to the present disclosure.

[0026] The above-mentioned figures include the following reference numerals: 10, absorption tower; 11, installation space; 111, pre-washing section; 112, absorption section; 113, cooling section; 114, spray section; 115, packing section; 20, spray structure; 30, first heat exchanger; 100, regeneration tower; 110, first connecting pipeline; 120, second heat exchanger; 130, first branch pipeline; 140, second connecting pipeline; 150, third heat exchanger; 160, second branch pipeline; 170, third connecting pipeline; 180, regeneration gas separator; 190, fourth connecting pipeline; 200, fifth connecting pipeline; 210, third branch pipeline. Detailed Implementation

[0027] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this disclosure or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0028] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this disclosure. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms “comprising” and / or “including” are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0029] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of this disclosure. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0030] In related technologies, the following problems exist in the process of carbon dioxide capture using chemical absorption:

[0031] (1) During the carbon dioxide capture process by chemical absorption, due to the high volatility of organic amine solution, the organic amine solution in each section of the absorption tower will be carried out with the flue gas at the bottom of the tower, resulting in amine escape, which leads to higher pollutant emissions at the outlet of the absorption tower, increased absorbent loss, and continuous increase in carbon capture operation costs.

[0032] (2) Water washing is currently the most common method for controlling amine escape. Although the amine capture efficiency at the top of the absorption section can reach more than 95% by traditional water washing, the amine concentration in the flue gas discharged after water washing is still higher than 45 ppm, which is higher than the relevant emission standards.

[0033] (3) The temperature of the regeneration gas in the regeneration tower is relatively high, generally 90°C to 100°C. The conventional process is to remove this part of the heat using a regeneration gas water cooler, so this part of the heat is used less.

[0034] (4) In traditional processes, the condensate in the regenerated gas separator is usually sent back to the regeneration tower, and this part of the condensate and cooling capacity is not fully utilized.

[0035] As shown in Figure 1, the carbon dioxide absorption device in the flue gas of this embodiment includes an absorption tower 10. The absorption tower 10 has an installation space 11 and an inlet and an outlet connected to the installation space 11. The installation space 11 includes a pre-washing section 111, an absorption section 112, a cooling section 113, a spray section 114, and a packing section 115. An organic amine solution is disposed in the absorption section 112. The inlet is connected to the pre-washing section 111. The absorption section 112 is located above the pre-washing section 111, the cooling section 113 is located above the absorption section 112, the spray section 114 is located above the cooling section 113, and the packing section 115 is located above the spray section 114 and connected to the outlet. The flue gas flows from the pre-washing section 111 to the packing section 115.

[0036] Using the technical solution of this embodiment, the absorption tower 10 is provided with an installation space 11, an inlet, and an outlet, both of which are connected to the installation space 11. The installation space 11 includes a pre-washing section 111, an absorption section 112, a cooling section 113, a spray section 114, and a packing section 115 arranged sequentially. An organic amine solution is provided in the absorption section 112. The inlet is connected to the pre-washing section 111, and the outlet is connected to the packing section 115. The flue gas flows from the pre-washing section 111 to the packing section 115. Through the above arrangement, the flue gas can enter the installation space 11 through the inlet and pass through the pre-washing section 111, the absorption section 112, the cooling section 113, the spray section 114, and the packing section 115 in sequence, before flowing out through the outlet. The pre-washing section 111 can pre-treat the flue gas, removing trace amounts of gypsum and other impurities carried by the flue gas. The organic amine solution in the absorption section 112 can absorb carbon dioxide in the flue gas. The cooling section 113 can reduce the temperature of the flue gas. The spray section 114 can spray liquid, and the liquid sprayed by the spray section 114 can directly contact the flue gas, absorbing organic amine molecules in the flue gas and further reducing the concentration of amines in the emitted flue gas. The packing section 115 can further reduce the content of organic amine molecules and aerosols and other impurities in the flue gas, that is, reduce the concentration of amines in the emitted flue gas. Therefore, the technical solution of this embodiment effectively solves the problem of high amine concentration in the flue gas emitted by the absorption tower 10 in related technologies.

[0037] It should be noted that "liquid" refers to water.

[0038] As shown in Figure 1, in this embodiment, the cooling section 113 includes a dry packing layer, and the packing section 115 includes a wet packing layer. The flue gas temperature decreases when passing through the dry packing layer. When the flue gas moves within the wet packing section 115, it comes into contact with the moisture within the wet packing section 115, thereby further reducing the content of impurities such as organic amine molecules and aerosols in the flue gas.

[0039] As shown in Figure 1, in this embodiment, the carbon dioxide absorption device in the flue gas further includes a spray structure 20 and a first heat exchanger 30. The spray structure 20 is disposed at the spray section 114. The absorption tower 10 includes a first liquid inlet and a first liquid outlet spaced apart at the spray section 114. The first end of the first heat exchanger 30 is connected to the first liquid outlet, and the second end of the first heat exchanger 30 is connected to the first liquid inlet. The first liquid inlet is connected to the spray structure 20. Liquid can be sprayed into the spray section 114 through the spray structure 20. The sprayed liquid can absorb impurities such as organic amine molecules and aerosols in the flue gas. The first heat exchanger 30 can absorb the heat of the liquid flowing out through the first liquid outlet and transport the lower-temperature liquid through the first liquid inlet into the spray section 114 to absorb impurities such as organic amine molecules and aerosols in the flue gas again.

[0040] The spray structure 20 includes multiple spray heads. The first heat exchanger 30 includes an exhaust gas scrubbing heat exchanger.

[0041] As shown in Figure 1, the flue gas purification device of this embodiment includes a carbon dioxide absorption device for flue gas and a regeneration tower 100 connected to the carbon dioxide absorption device. The carbon dioxide absorption device is the one described above. In use, the cooling section 113 reduces the temperature of the flue gas, the spraying section 114 absorbs organic amine molecules in the flue gas, and the packing section 115 reduces the concentration of organic amine molecules in the flue gas, thereby reducing the concentration of amines in the discharged flue gas. The flue gas purification device with the carbon dioxide absorption device described above also has the aforementioned advantages.

[0042] As shown in Figure 1, in this embodiment, the flue gas purification device further includes a first connecting pipeline 110, a second heat exchanger 120, and a first branch pipeline 130. The regeneration tower 100 has a second liquid inlet and a third liquid inlet spaced apart. The first end of the first connecting pipeline 110 is connected to the bottom of the absorption section 112 of the carbon dioxide absorption device in the flue gas. The first end of the second heat exchanger 120 is connected to the second end of the first connecting pipeline 110, and the second end of the second heat exchanger 120 is connected to the second liquid inlet. The first end of the first branch pipeline 130 is connected to the second end of the first connecting pipeline 110, and the second end of the first branch pipeline 130 is connected to the third liquid inlet. After the organic amine solution reacts with carbon dioxide in the absorption section 112, part of it can flow from the first connecting pipeline 110 to the first branch pipeline 130 and enter the regeneration tower 100 for quenching through the third liquid inlet. The other part can enter the regeneration tower 100 sequentially through the second heat exchanger 120 and the second liquid inlet. The second heat exchanger 120 can heat the organic amine solution rich in carbon dioxide, and the regeneration tower 100 can desorb the organic amine solution rich in carbon dioxide after it has been heated by the second heat exchanger 120, thereby regenerating the carbon dioxide gas.

[0043] As shown in Figure 1, in this embodiment, the flue gas purification device further includes a second connecting pipeline 140, a third heat exchanger 150, a second branch pipeline 160, and a third connecting pipeline 170. The third heat exchanger 150 has a fourth liquid inlet and a fifth liquid inlet spaced apart. The third heat exchanger 150 also includes a second liquid outlet. The first end of the second connecting pipeline 140 is connected to the top of the regeneration tower 100, and the second end of the second connecting pipeline 140 is connected to the fourth liquid inlet. The first ends of the second branch pipeline 160 and the first ends of the first branch pipeline 130 are both connected to the second end of the first connecting pipeline 110 through the third connecting pipeline 170. The second end of the second branch pipeline 160 is connected to the fifth liquid inlet, and the second liquid outlet is connected to the packing section 115. The high-temperature regeneration gas discharged from the regeneration tower 100 can enter the third heat exchanger 150 via the second connecting pipeline 140 to heat the carbon dioxide-rich organic amine solution flowing in via the second branch pipeline 160. This utilizes the excess heat in the third heat exchanger 150, thereby greatly reducing regeneration energy consumption. The third connecting pipeline 170 connects the first connecting pipeline 110 and the first branch pipeline 130, and also connects the first connecting pipeline 110 and the second branch pipeline 160.

[0044] The third heat exchanger 150 includes a regeneration gas cooler.

[0045] As shown in Figure 1, in this embodiment, the flue gas purification device further includes a regenerator 180 and a fourth connecting pipeline 190. A second liquid outlet is connected to the regenerator 180, which has a third liquid outlet. The absorption tower 10 has a sixth liquid inlet located at the packing section 115. The first end of the fourth connecting pipeline 190 is connected to the third liquid outlet, and the second end is connected to the sixth liquid inlet. The condensate separated in the regenerator 180 has a lower temperature and fewer impurities, allowing it to enter the absorption tower 10 via the fourth connecting pipeline 190. This serves both as makeup water and reduces the temperature of the condensate fed into the packing section 115, thereby improving the recovery rate of organic amines in the flue gas.

[0046] The condensate separated in the regenerated gas separator 180 is generally below 30°C. The gas discharged from the regenerated gas separator flows to the carbon dioxide compressor.

[0047] As shown in Figure 1, in this embodiment, the flue gas purification device further includes a fifth connecting pipeline 200, and the absorption tower 10 also has a fourth liquid outlet located at the packing section 115. The first end of the fifth connecting pipeline 200 is connected to the fourth liquid outlet, the second end of the fifth connecting pipeline 200 is connected to a sixth liquid inlet, and the second end of the fourth connecting pipeline 190 is connected to the middle of the fifth connecting pipeline 200. The fifth connecting pipeline 200 allows liquid flowing out of the packing section 115 to flow back into the packing section 115. Condensate flowing in the fourth connecting pipeline 190 can flow out through the fifth connecting pipeline 200 into the packing section 115.

[0048] As shown in Figure 1, in this embodiment, the flue gas purification device further includes a third branch pipeline 210. The regeneration tower 100 has a seventh liquid inlet. The first end of the third branch pipeline 210 is connected to the middle of the fifth connecting pipeline 200 and is located between the fourth liquid outlet and the second end of the fourth connecting pipeline 190. The second end of the third branch pipeline 210 is connected to the seventh liquid inlet. The third branch pipeline 210 allows the condensate flowing out of the fifth connecting pipeline 200 to flow into the regeneration tower 100 to ensure the water balance of the regeneration tower 100.

[0049] The flue gas purification device in this embodiment has the following advantages:

[0050] (1) Amine Escape and Aerosol Control at the Top of Absorber 10: Amine emission control is divided into three sections (from bottom to top: cooling section 113, spray section 114, and packing section 115). The first section uses cooling section 113, where the flue gas from the outlet of absorption section 112 passes through an empty packed tower. The dry packing layer of cooling section 113 significantly reduces the temperature of the flue gas, while simultaneously recovering gaseous organic amines and other organic compounds, reducing the organic amine content in the flue gas by ten orders of magnitude. Spray section 114 sprays circulating water through spray heads, allowing direct contact with the flue gas and absorbing organic amine molecules. The outlet of spray section 114 is cooled by a tail gas scrubbing heat exchanger before returning to spray section 114, ensuring that spray section 114 has a low operating temperature (below 30°C) and improving the capture rate of organic amines in the flue gas. Circulating water is introduced into the upper part of the packing section 115, and the flue gas comes into contact with the circulating water in the packing from bottom to top, further reducing the content of impurities such as organic amine molecules and aerosols in the flue gas. The removal rate of aerosols with a diameter greater than 3μm through the spray section 114 and the packing section 115 can reach over 99%. A baffle plate demister or wire mesh demister is installed at the top of the packing section 115 according to the liquid particle size distribution at the flue gas outlet, achieving a removal rate of over 99.99% for aerosols with a particle size less than 3μm at the outlet of the packing section 115. Finally, a wet electrostatic precipitator is added to further remove aerosols with a particle size less than 3μm in the flue gas, achieving an amine concentration of less than 10ppm at the outlet of the absorption tower 10.

[0051] (2) Utilization of heat from carbon dioxide regeneration gas: The heat in the carbon dioxide regeneration gas at the outlet of regeneration tower 100 is recycled and utilized. A portion of the organic amine solution rich in carbon dioxide at the bottom of absorption tower 10 is extracted and exchanged with the regeneration gas at the top outlet of regeneration tower 100. After absorbing the heat in this portion of the regeneration gas, the organic amine solution rich in carbon dioxide can increase the temperature of this portion of the organic amine solution rich in carbon dioxide, and then it is sent back to regeneration tower 100 for regeneration.

[0052] (3) Utilization of cooling capacity of condensate from regenerated gas separator 180: After cooling, the condensate obtained by regenerated gas through regenerated gas separator 180 has a low temperature. Since there are fewer impurities in the water in regenerated gas separator 180, it is sent to the outlet of packing section 115 at the top of absorption tower 10. It can be used as makeup water and can also reduce the temperature of condensate sent to wet conditioning section, thereby improving the recovery rate of organic amines in flue gas at the outlet of absorption tower 10.

[0053] (4) The amine recovery and escape control section at the top of the absorber 10 consists of three parts: a cooling section 113, a spray section 114, and a packing section 115. The cooling section 113 uses conventional M250Y or M252Y type packing. The cooling section 113 is generally only wetted with a small amount of water, which can significantly reduce the flue gas temperature and is used to recover organic amines and other organic substances in the flue gas at the outlet of the absorber section 112. Through the cooling section 113, the amount of organic amines entrained at the outlet of the absorber section 112 can generally be reduced by an order of magnitude. The spray section 114 sprays low-temperature circulating water into the tower to dissolve the gaseous organic substances entrained in the flue gas. The packing section 115 also uses conventional M250Y or M252Y type packing, and generally introduces low-temperature circulating water to further remove gaseous organic substances and aerosols and other impurities in the flue gas. Acids such as sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid, chromic acid, hydrofluoric acid, and mixed acids can be added to the circulating water in the spray section 114 and the packing section 115 to control aerosol generation, thereby improving the removal rate of gaseous organic matter. A baffle plate demister or wire mesh demister is installed on the packing section 115 according to the particle size distribution of the liquid at the flue gas outlet, and finally a wet electrostatic precipitator is installed.

[0054] (5) Utilization of heat from regenerated gas: Part of the rich liquid from the absorption tower 10 is sent to the regenerated gas cooler for heating, and part is sent to the regeneration tower 100 for quenching. The high-temperature regenerated gas discharged from the top of the regeneration tower 100 is sent to the third heat exchanger 150 to heat part of the rich liquid from the absorption tower 10. This allows the use of excess heat in the third heat exchanger 150, thereby greatly reducing regeneration energy consumption.

[0055] (6) The condensate separated in the regenerated gas separator 180 has a low temperature (generally below 30℃). Since there are fewer impurities in the water in the regenerated gas separator 180, it is sent to the top packing section 115 of the absorption tower 10. This serves as makeup water and also reduces the temperature of the condensate sent to the wet conditioning section, thereby improving the recovery rate of organic amines in the flue gas at the outlet of the absorption tower 10. To ensure the water balance of the regeneration tower 100 section, a branch is set at the outlet of the packing section 115 at the top of the absorption tower 10, and the discharged condensate can be returned to the regeneration tower 100 section.

[0056] The flow rate of the first connecting pipeline 110 is 4000 t / h, and the temperature of the fluid flowing in the first connecting pipeline 110 is 40℃ to 50℃. The flow rate of the third connecting pipeline 170 is 500 t / h. The flow rate of the first branch pipeline 130 is 300 t / h, and the temperature of the fluid flowing in the first branch pipeline 130 is 40℃ to 50℃. The flow rate of the second branch pipeline 160 is 200 t / h, and the temperature of the fluid flowing in the second branch pipeline 160 is 40℃ to 50℃. The flow rate of the fourth connecting pipeline 190 is 40 t / h, and the temperature of the fluid flowing in the fourth connecting pipeline 190 is 40℃ to 50℃. The flow rate of the second connecting pipeline 140 is 220 t / h, and the temperature of the fluid flowing in the second connecting pipeline 140 is 85℃ to 105℃. The flow rate of the third branch pipeline 210 is 40t / h, and the temperature of the fluid flowing in the third branch pipeline 210 is 40℃ to 50℃.

[0057] As shown in Figure 1, the control method of the flue gas purification device in this embodiment controls the flue gas purification device. The control method of the flue gas purification device includes:

[0058] The on / off state of the first branch pipeline 130 and the first connecting pipeline 110 is controlled according to the flow rate of the first branch pipeline 130.

[0059] The on / off state of the first branch pipeline 130 and the first connecting pipeline 110, and the on / off state of the second branch pipeline 160 and the first connecting pipeline 110 are controlled based on the sum of the flow rates of the first branch pipeline 130 and the second branch pipeline 160.

[0060] With the above settings, the on / off state of the first branch line 130 and the first connecting line 110 can be controlled, as can the on / off state of the second branch line 160 and the first connecting line 110, thereby controlling the flow of the carbon dioxide-rich organic amine solution.

[0061] It should be noted that either of the above two steps can control the on / off state of the first branch pipeline 130 and the first connecting pipeline 110.

[0062] The steps for controlling the connection between the first branch pipeline 130 and the first connecting pipeline 110 based on the flow rate of the first branch pipeline 130 include:

[0063] When the flow rate of the first branch pipeline 130 exceeds the first threshold, the connection between the first branch pipeline 130 and the first connecting pipeline 110 is disconnected. The first threshold is greater than or equal to one-fifth of the sum of the flow rates of the first branch pipeline 130 and the second branch pipeline 160 and less than or equal to three-fifths of the sum of the flow rates of the first branch pipeline 130 and the second branch pipeline 160.

[0064] With the above settings, the connection and disconnection between the first branch pipeline 130 and the first connecting pipeline 110 can be controlled according to the flow rate of the first branch pipeline 130.

[0065] The steps of simultaneously controlling the connection between the first branch pipeline 130 and the first connecting pipeline 110 and the connection between the second branch pipeline 160 and the first connecting pipeline 110 based on the sum of the flow rates of the first branch pipeline 130 and the second branch pipeline 160 include:

[0066] When the sum of the flow rate of the first branch pipeline 130 and the flow rate of the second branch pipeline 160 exceeds the second threshold, the connection between the first branch pipeline 130 and the first connecting pipeline 110 and the connection between the second branch pipeline 160 and the first connecting pipeline 110 are cut off, wherein the second threshold is greater than or equal to one-eighth of the flow rate of the first connecting pipeline 110.

[0067] With the above settings, the connection between the first branch pipeline 130 and the first connecting pipeline 110 can be controlled according to the flow rate of the first branch pipeline 130 and the flow rate of the second branch pipeline 160, and the connection between the second branch pipeline 160 and the first connecting pipeline 110 can also be controlled.

[0068] In the description of this disclosure, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings and is only for the convenience of describing this disclosure and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this disclosure; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0069] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0070] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this disclosure.

[0071] The above description is merely a preferred embodiment of this disclosure and is not intended to limit this disclosure. Various modifications and variations can be made to this disclosure by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A device for absorbing carbon dioxide in flue gas, comprising: An absorption tower (10) is provided with an installation space (11) and an inlet and an outlet connected to the installation space (11). The installation space (11) includes a pre-washing section (111), an absorption section (112), a cooling section (113), a spraying section (114), and a packing section (115). An organic amine solution is provided in the absorption section (112). The inlet is connected to the pre-wash section (111), the absorption section (112) is located above the pre-wash section (111), the cooling section (113) is located above the absorption section (112), the spray section (114) is located above the cooling section (113), the packing section (115) is located above the spray section (114) and is connected to the outlet, and the flue gas flows from the pre-wash section (111) to the packing section (115).

2. The carbon dioxide absorption device in flue gas according to claim 1, wherein the cooling section (113) includes a dry packing layer and the packing section (115) includes a wet packing layer.

3. The carbon dioxide absorption device in flue gas according to claim 1 or 2, wherein the carbon dioxide absorption device in flue gas further includes a spray structure (20) and a first heat exchanger (30), the spray structure (20) is disposed at the spray section (114), the absorption tower (10) includes a first liquid inlet and a first liquid outlet disposed at intervals at the spray section (114), the first end of the first heat exchanger (30) is connected to the first liquid outlet, the second end of the first heat exchanger (30) is connected to the first liquid inlet, and the first liquid inlet is connected to the spray structure (20).

4. A flue gas purification device, comprising a device for absorbing carbon dioxide in flue gas and a regeneration tower (100) connected to the device for absorbing carbon dioxide in flue gas, wherein the device for absorbing carbon dioxide in flue gas is the device for absorbing carbon dioxide in flue gas according to any one of claims 1 to 3.

5. The flue gas purification device according to claim 4, wherein the flue gas purification device further comprises a first connecting pipeline (110), a second heat exchanger (120) and a first branch pipeline (130), the regeneration tower (100) having a second liquid inlet and a third liquid inlet spaced apart, the first end of the first connecting pipeline (110) being connected to the bottom of the absorption section (112) of the carbon dioxide absorption device in the flue gas, the first end of the second heat exchanger (120) being connected to the second end of the first connecting pipeline (110), the second end of the second heat exchanger (120) being connected to the second liquid inlet, the first end of the first branch pipeline (130) being connected to the second end of the first connecting pipeline (110), and the second end of the first branch pipeline (130) being connected to the third liquid inlet.

6. The flue gas purification device according to claim 5, wherein the flue gas purification device further comprises a second connecting pipeline (140), a third heat exchanger (150), a second branch pipeline (160) and a third connecting pipeline (170), the third heat exchanger (150) having a fourth liquid inlet and a fifth liquid inlet spaced apart, the third heat exchanger (150) further comprising a second liquid outlet, the first end of the second connecting pipeline (140) being connected to the top of the regeneration tower (100), the second end of the second connecting pipeline (140) being connected to the fourth liquid inlet, the first end of the second branch pipeline (160) and the first end of the first branch pipeline (130) being connected to the second end of the first connecting pipeline (110) through the third connecting pipeline (170), the second end of the second branch pipeline (160) being connected to the fifth liquid inlet, and the second liquid outlet being connected to the packing section (115).

7. The flue gas purification device according to claim 6, wherein the flue gas purification device further includes a regenerated gas separator (180) and a fourth connecting pipeline (190), the second liquid outlet is connected to the regenerated gas separator (180), the regenerated gas separator (180) has a third liquid outlet, the absorption tower (10) has a sixth liquid inlet disposed at the packing section (115), the first end of the fourth connecting pipeline (190) is connected to the third liquid outlet, and the second end of the fourth connecting pipeline (190) is connected to the sixth liquid inlet.

8. The flue gas purification device according to claim 7, wherein the flue gas purification device further includes a fifth connecting pipeline (200), the absorption tower (10) further has a fourth liquid outlet disposed at the packing section (115), the first end of the fifth connecting pipeline (200) is connected to the fourth liquid outlet, the second end of the fifth connecting pipeline (200) is connected to the sixth liquid inlet, and the second end of the fourth connecting pipeline (190) is connected to the middle part of the fifth connecting pipeline (200).

9. The flue gas purification device according to claim 8, wherein the flue gas purification device further includes a third branch pipeline (210), the regeneration tower (100) has a seventh liquid inlet, the first end of the third branch pipeline (210) is connected to the middle of the fifth connecting pipeline (200) and is located between the fourth liquid outlet and the second end of the fourth connecting pipeline (190), and the second end of the third branch pipeline (210) is connected to the seventh liquid inlet.

10. A control method for a flue gas purification device, controlling the flue gas purification device according to any one of claims 4 to 9, wherein the control method for the flue gas purification device comprises: The on / off state of the first branch pipeline (130) and the first connecting pipeline (110) is controlled according to the flow rate of the first branch pipeline (130); The on / off state of the first branch pipeline (130) and the first connecting pipeline (110) and the on / off state of the second branch pipeline (160) are controlled according to the sum of the flow rate of the first branch pipeline (130) and the flow rate of the second branch pipeline (160).

11. The control method of the flue gas purification device according to claim 10, the step of controlling the connection between the first branch pipeline (130) and the first connecting pipeline (110) according to the flow rate of the first branch pipeline (130) includes: When the flow rate of the first branch line (130) exceeds the first threshold, the connection between the first branch line (130) and the first connecting line (110) is disconnected. The first threshold is greater than or equal to one-fifth of the sum of the flow rate of the first branch line (130) and the flow rate of the second branch line (160) and less than or equal to three-fifths of the sum of the flow rate of the first branch line (130) and the flow rate of the second branch line (160).

12. The control method of the flue gas purification device according to claim 11, the step of simultaneously controlling the connection between the first branch pipeline (130) and the first connecting pipeline (110) and the connection between the second branch pipeline (160) and the first connecting pipeline (110) based on the sum of the flow rate of the first branch pipeline (130) and the flow rate of the second branch pipeline (160) includes: When the sum of the flow rate of the first branch line (130) and the flow rate of the second branch line (160) exceeds a second threshold, the connection between the first branch line (130) and the first connecting line (110) and the connection between the second branch line (160) and the first connecting line (110) are cut off, wherein the second threshold is greater than or equal to one-eighth of the flow rate of the first connecting line (110).

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