A low-concentration carbon dioxide recovery and refining device

Abstract

The present invention relates to the technical field of carbon dioxide recovery and refining, and in particular to a low-concentration carbon dioxide recovery and refining device, comprising: a water-washing desulfurization unit, a carbon dioxide absorption unit, including an absorption component and a desorption component; a detection unit for respectively detecting the carbon dioxide concentration, the gas rising velocity at the gas inlet of the second absorption tower, the carbon dioxide absorption amount in the second absorption tower, the flow rate of the feed gas, and the flow rate of the carbon dioxide; and a control unit for respectively determining the pressure and vertical height of the nozzle according to the gas rising velocity and the carbon dioxide absorption amount, and determining the temperature of the rich liquid cooler according to the increase in the carbon dioxide concentration in the first absorption tower. This device solves the problem of low carbon dioxide recovery efficiency caused by the reduced contact area when the carbon dioxide absorbent re-enters the first absorption tower and contacts the feed gas in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon dioxide recovery and refining, and in particular to a low-concentration carbon dioxide recovery and refining device. Background Art

[0002] Low concentration of carbon dioxide ( Efficient recycling of wastewater (concentrations typically below 20%) has become a key challenge in industrial emission reduction and resource-based transformation. However, existing technologies face bottlenecks in practical applications, including low recycling efficiency, high energy consumption, and poor economic efficiency.

[0003] Chinese Patent Publication No. CN102019132B discloses a carbon dioxide recovery system, comprising: an absorber, which introduces exhaust gas containing carbon dioxide into contact with an absorbent, and allows the absorbent to absorb carbon dioxide in the exhaust gas, and the absorber reversibly absorbs or releases carbon dioxide above or below a predetermined temperature level; a regenerator, which releases carbon dioxide in the absorbent by heating the absorbent that has absorbed carbon dioxide and is located in the absorber; a reflux pipe, which flows the absorbent regenerated from the regenerator back to the absorber; and a filter, which is used to introduce at least part of the absorbent, remove solids accumulated in the introduced absorbent, and return the absorbent after the solids are removed to the vicinity of the site where the absorbent is introduced.

[0004] It can be seen from this that in the carbon dioxide recovery system, part of the raw gas leaves the second absorption tower without coming into contact with the carbon dioxide absorbent, resulting in low carbon dioxide recovery utilization rate; and because the carbon dioxide absorbent in the first absorption tower absorbs carbon dioxide and causes increased viscosity, the contact area of ​​the carbon dioxide absorbent re-entering the first absorption tower and the raw gas decreases, resulting in low carbon dioxide recovery efficiency. Summary of the Invention

[0005] To this end, the present invention provides a low-concentration carbon dioxide recovery and refining device to overcome the problems in the prior art of low carbon dioxide recovery utilization rate due to part of the raw gas leaving the second absorption tower without contacting the carbon dioxide absorbent, and low carbon dioxide recovery efficiency due to increased viscosity of the carbon dioxide absorbent in the first absorption tower absorbing carbon dioxide, resulting in a decrease in contact area when the carbon dioxide absorbent re-enters the first absorption tower and contacts the raw gas.

[0006] To achieve the above-mentioned object, the present invention provides a low-concentration carbon dioxide recovery and purification device, comprising:

[0007] Water washing and desulfurization unit, used to wash, cool and desulfurize the raw gas;

[0008] a carbon dioxide absorption unit connected to the water-washing desulfurization unit, comprising an absorption assembly for absorbing carbon dioxide from the feed gas through a carbon dioxide absorbent, and a desorption assembly connected to the absorption assembly for releasing carbon dioxide from the carbon dioxide absorbent to obtain gaseous carbon dioxide, the absorption assembly comprising a first absorption tower and a second absorption tower, a nozzle disposed at the top of the second absorption tower for spraying the carbon dioxide absorbent, a movement assembly connected to the nozzle for controlling the vertical movement of the nozzle, and a rich liquid cooler for cooling the absorbed carbon dioxide absorbent output from the first absorption tower;

[0009] a detection unit connected to the carbon dioxide absorption unit, for respectively detecting the carbon dioxide concentration, the gas rising speed at the gas inlet of the second absorption tower, the carbon dioxide absorption amount in the second absorption tower, the flow rate of the feed gas, and the flow rate of the carbon dioxide;

[0010] A control unit is respectively connected to the water washing and desulfurization unit, the carbon dioxide absorption unit and the detection unit, and is used to determine the pressure and vertical height of the nozzle according to the gas rising speed and the carbon dioxide absorption amount, and to determine the temperature of the rich liquid cooler according to the increase in the carbon dioxide concentration of the first absorption tower.

[0011] Furthermore, the absorption component further comprises:

[0012] a wire mesh demister, which is arranged above the nozzle and is used to eliminate bubbles generated by the combination of the carbon dioxide absorbent and the raw gas;

[0013] a first rich liquid pump connected to the bottom of the first absorption tower, for pumping out the absorbed carbon dioxide absorbent at the bottom of the first absorption tower;

[0014] a rich liquid circulation pump, disposed between the first absorption tower and the rich liquid cooler, for circulating the absorbed carbon dioxide absorbent at the bottom of the first absorption tower to the top of the first absorption tower;

[0015] a second rich liquid pump, disposed between the first absorption tower and the second absorption tower, for pumping the carbon dioxide absorbent in the absorbed state at the bottom of the second absorption tower to the top of the first absorption tower;

[0016] a lean liquid cooler, which is provided on the lean liquid conveying pipeline connected to the nozzle, and is used to cool the carbon dioxide absorbent flowing through the lean liquid conveying pipeline after the release;

[0017] The filter is arranged between the lean liquid cooler and the nozzle, and is used to filter the carbon dioxide absorbent that has finished being released and flows through the lean liquid conveying pipeline.

[0018] Furthermore, the parsing component includes:

[0019] a lean-rich liquid heat exchanger connected to the first rich liquid pump via a rich liquid delivery pipeline and to the lean liquid cooler via the lean liquid delivery pipeline, for performing heat exchange between the carbon dioxide absorbent that has finished releasing and flows through the lean liquid delivery pipeline and the carbon dioxide absorbent in an absorbed state and flows through the rich liquid delivery pipeline;

[0020] a desorption tower connected to the lean and rich liquid heat exchanger via a rich liquid delivery pipeline, for releasing carbon dioxide from the carbon dioxide absorbent in an absorbed state to obtain gaseous carbon dioxide;

[0021] a lean liquid pump connected to the bottom of the desorption tower, for pumping the carbon dioxide absorbent at the bottom of the desorption tower that has finished being released into the lean liquid delivery pipeline;

[0022] A gas output pipeline is connected to the top of the analytical tower and is used to output the gaseous carbon dioxide.

[0023] Furthermore, the detection unit includes:

[0024] a first carbon dioxide concentration sensor, which is arranged in the air inlet passage of the cooling water washing tower in the water washing and desulfurization unit, and is used to detect the carbon dioxide concentration before the cooling water washing;

[0025] a second carbon dioxide concentration sensor, which is arranged in the gas output pipeline and is used to detect the carbon dioxide concentration in the gas output pipeline;

[0026] a third carbon dioxide concentration sensor, disposed in the first absorption tower, for detecting the carbon dioxide concentration in the first absorption tower;

[0027] a first gas flow sensor, which is arranged in the air inlet passage of the cooling water washing tower in the water washing and desulfurization unit, and is used to detect the flow rate of the raw gas flowing through the air inlet passage;

[0028] a second gas flow sensor, which is arranged in the gas output pipeline and is used to detect the flow rate of carbon dioxide in the gas output pipeline;

[0029] an ultrasonic flow meter, which is provided at the gas inlet of the second absorption tower and is used to detect the gas rising velocity of the raw gas at the gas inlet of the second absorption tower;

[0030] An online pH sensor is provided at the bottom of the second absorption tower, and is used to detect the pH value of the carbon dioxide absorbent in the bottom of the second absorption tower to determine the carbon dioxide absorption amount of the carbon dioxide absorbent.

[0031] Furthermore, the control unit is connected to the first carbon dioxide concentration sensor, the second carbon dioxide concentration sensor, the first gas flow sensor, and the second gas flow sensor, and is used to respectively obtain the carbon dioxide concentration before the cooling water washing, the carbon dioxide concentration of the gas output pipeline, the flow rate of the raw gas in the air intake channel, and the carbon dioxide flow rate of the gas output pipeline; determine the initial detection amount of carbon dioxide in the raw gas according to the carbon dioxide concentration before the cooling water washing and the flow rate of the raw gas in the air intake channel; determine the carbon dioxide output of the analysis component according to the carbon dioxide concentration of the gas output pipeline and the carbon dioxide flow rate of the gas output pipeline; and determine the recovery status of carbon dioxide according to the difference between the initial detection amount of carbon dioxide in the raw gas and the carbon dioxide output of the analysis component, wherein,

[0032] If the ratio of the difference to the initial detection amount is greater than or equal to the preset loss ratio, it is determined that the carbon dioxide recovery is abnormal, and the carbon dioxide concentration, the gas rising speed, the carbon dioxide absorption amount, the flow rate of the raw gas, and the flow rate of the carbon dioxide are collected to further determine the abnormal state;

[0033] If the ratio of the difference to the initial detection amount is less than the preset loss ratio, it is determined that the carbon dioxide recovery is normal.

[0034] Furthermore, the initial detection amount is the integral value of the product of the function of the carbon dioxide concentration relative to time and the function of the flow rate of the raw gas in the intake channel relative to time within a preset sampling period before the cooling water washing.

[0035] Furthermore, the carbon dioxide output is an integral value of the product of a carbon dioxide concentration in the gas output pipeline as a function of time and a carbon dioxide flow rate in the gas output pipeline as a function of time within a preset sampling period.

[0036] Furthermore, the control unit is connected to the nozzle, and is used to further determine that the nozzle is abnormal based on the gas rising speed being less than the first preset gas rising speed and the carbon dioxide absorption amount being greater than the preset carbon dioxide absorption amount, and increase the pressure of the nozzle.

[0037] Furthermore, the control unit is connected to the moving component to further determine that the vertical height of the nozzle is abnormal based on the gas rising speed being greater than or equal to a first preset gas rising speed and less than a second preset gas rising speed and based on the carbon dioxide absorption amount being less than or equal to a preset carbon dioxide absorption amount, and increase the vertical height of the nozzle through the moving component.

[0038] Furthermore, the control unit is connected to the rich liquid cooler, and is used to further determine that the temperature of the rich liquid cooler is abnormal based on the increase in carbon dioxide concentration in the first absorption tower being greater than a preset increase in carbon dioxide concentration, and to lower the temperature of the rich liquid cooler.

[0039] Compared with the prior art, the present invention has the beneficial effect that, by further determining that the nozzle is abnormal based on the fact that the gas rising speed is less than the first preset gas rising speed and the carbon dioxide absorption amount is greater than the preset carbon dioxide absorption amount, and increasing the pressure of the nozzle, the present invention solves the problem that due to the impact of the raw gas, part of the metal powder of the wire mesh demister falls into the nozzle, causing the direction of the nozzle to change, so that the nozzle sprays carbon dioxide absorbent toward the gas inlet of the second absorption tower, hindering the raw gas from entering the second absorption tower, causing the entry speed of the raw gas to slow down, and further causing the vertical contact position of the raw gas and the carbon dioxide absorbent to shift downward. Due to the downward shift of the vertical contact position of the raw gas and the carbon dioxide absorbent, part of the carbon dioxide absorbent may have repolymerized, resulting in part of the raw gas leaving the second absorption tower without contacting the carbon dioxide absorbent, resulting in the carbon dioxide not being completely absorbed into the carbon dioxide absorbent, resulting in the difference between the carbon dioxide output output by the analysis component within the preset sampling period and the initial detection amount of carbon dioxide in the raw gas and the proportion of the initial detection amount being greater than or equal to the preset loss proportion, thereby resulting in low utilization rate of carbon dioxide recovery. By increasing the pressure of the nozzle and thus reducing the upward flow rate of the raw gas, the probability of some metal powder in the wire mesh demister falling into the nozzle due to the impact of the raw gas and causing the direction of the nozzle to change is reduced, thereby improving the utilization rate of carbon dioxide recovery.

[0040] Furthermore, by obtaining the amount of carbon dioxide absorbed by the carbon dioxide absorbent in the second absorption tower, the vertical height of the nozzle is increased by the moving component based on the gas rise speed being greater than or equal to the first preset gas rise speed and less than the second preset gas rise speed, and based on the carbon dioxide absorbed by the carbon dioxide absorbent in the second absorption tower being less than or equal to the preset carbon dioxide absorption amount. This solves the problem that when the wire mesh demister, due to the impact of the raw gas, causes part of its metal powder to fall into the nozzle, the nozzle direction changes, causing the nozzle to spray carbon dioxide absorbent toward the gas inlet of the second absorption tower, hindering the raw gas from entering the second absorption tower, resulting in a slower entry speed of the raw gas. At this time, some carbon dioxide absorbent reaches the bottom of the second absorption tower without coming into contact with the raw gas. At this time, the raw gas just leaves the second absorption tower in large quantities during the time interval for the next carbon dioxide absorbent spray from the nozzle, resulting in not all carbon dioxide being absorbed by the carbon dioxide absorbent. As a result, the difference between the carbon dioxide output output by the analysis component and the initial detection amount of carbon dioxide in the raw gas within the preset sampling period and the ratio of the initial detection amount to be greater than or equal to the preset loss ratio, thereby resulting in low carbon dioxide recovery utilization rate. By increasing the vertical height of the nozzle through the moving component, the time from the carbon dioxide absorbent being sprayed from the nozzle to falling to the bottom of the second absorption tower is increased, the probability of the carbon dioxide absorbent contacting the raw gas is increased, and the situation in which the carbon dioxide absorbent reaches the bottom of the second absorption tower without contacting the raw gas is avoided, thereby improving the utilization rate of carbon dioxide recovery.

[0041] Furthermore, by obtaining the increase in carbon dioxide concentration in the first absorption tower, and based on the increase in carbon dioxide concentration in the first absorption tower being greater than a preset increase in carbon dioxide concentration, it is determined that the density of the carbon dioxide absorbent is abnormal, and the temperature of the rich liquid cooler is reduced. This solves the problem that the carbon dioxide absorbent in the first absorption tower absorbs carbon dioxide, causing its viscosity to increase, resulting in a decrease in the contact area of ​​the carbon dioxide absorbent re-entering the first absorption tower when it contacts the feed gas, thereby weakening the carbon dioxide absorption capacity of the carbon dioxide absorbent, thereby causing carbon dioxide to be trapped in the first absorption tower and difficult to be absorbed by the carbon dioxide absorbent, and further causing the difference between the carbon dioxide output output of the analysis component within a preset sampling period and the initial detection amount of carbon dioxide in the feed gas and the proportion of the initial detection amount to be greater than or equal to a preset loss proportion, thereby resulting in low carbon dioxide recovery efficiency. By reducing the temperature of the rich liquid cooler, the temperature of the carbon dioxide absorbent re-entering the first absorption tower is lower than the temperature of the feed gas entering the first absorption tower. When the two come into contact, the moisture in the feed gas is cooled to form partial water, which enters the carbon dioxide absorbent, reducing the viscosity of the carbon dioxide absorbent, improving the carbon dioxide absorption capacity of the carbon dioxide absorbent, and improving the efficiency of carbon dioxide recovery.

[0042] Furthermore, the control unit determines the recovery status of carbon dioxide based on the difference between the initial detection amount of carbon dioxide in the raw gas and the carbon dioxide output of the analysis component, and determines that the carbon dioxide recovery is abnormal based on the ratio of the difference to the initial detection amount being greater than or equal to a preset loss ratio. This solves the problem that the recovery and utilization rate of carbon dioxide is difficult to quantify and track, solves the problem that the decline in the recovery and utilization rate of carbon dioxide has not been identified for a long time, and improves the utilization rate of carbon dioxide recovery. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a schematic structural diagram of a low-concentration carbon dioxide recovery and purification device according to an embodiment of the present invention;

[0044] Figure 2 This is a structural block diagram of a low-concentration carbon dioxide recovery and refining device according to an embodiment of the present invention;

[0045] Figure 3 This is a structural block diagram of a carbon dioxide absorption unit in a low-concentration carbon dioxide recovery and purification device according to an embodiment of the present invention;

[0046] Figure 4 This is a schematic structural diagram of a carbon dioxide absorption unit in a low-concentration carbon dioxide recovery and refining device according to an embodiment of the present invention;

[0047] In the figure, 1-water washing and desulfurization unit, 2-carbon dioxide absorption unit, 3-compression adsorption unit, 4-freezing and liquefaction unit, 11-cooling water washing tower, 12-desulfurization tower, 21-absorption component, 22-analysis component, 31-dehumidification component, 32-drying component, 210-first absorption tower, 211-second absorption tower, 212-nozzle, 213-moving component, 214-rich liquid cooler, 215-first pipeline , 216- venting water washing tower, 217- second pipeline, 218- wire mesh demister, 219- first rich liquid pump, 2110- rich liquid circulation pump, 2111- second rich liquid pump, 2112- lean liquid cooler, 2113- lean liquid delivery pipeline, 2114- filter, 220- lean and rich liquid heat exchanger, 221- rich liquid delivery pipeline, 222- analysis tower, 223- lean liquid pump, 224- gas output pipeline. DETAILED DESCRIPTION

[0048] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are merely used to explain the present invention and are not intended to limit the present invention.

[0049] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0050] Furthermore, it should be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0051] See also Figure 1 、 Figure 2 、 Figure 3 as well as Figure 4 As shown, they are respectively a structural schematic diagram, a structural block diagram, a structural block diagram of a carbon dioxide absorption unit, and a structural schematic diagram of a carbon dioxide absorption unit of an embodiment of the present invention.

[0052] The low-concentration carbon dioxide recovery and refining device according to the embodiment of the present invention comprises:

[0053] The water washing and desulfurization unit 1 is used for washing, cooling and desulfurizing the raw gas, and includes a cooling water washing tower 11 for cooling the raw gas and a desulfurization tower 12 connected to the cooling water washing tower 11 for desulfurizing the raw gas;

[0054] Specifically, the components of the raw gas include: hydrogen sulfide, oxygen, nitrogen, water vapor, hydrocarbon organic matter, carbon monoxide, carbon dioxide, sulfur dioxide, and nitrogen oxides.

[0055] Specifically, the water washing and cooling process of the raw gas by the cooling water washing tower is a conventional technical means well known to those skilled in the art, and the water washing and cooling process will not be described in detail here; the principle of desulfurization is to add alkaline substances such as sodium hydroxide to react with sulfur-containing substances to complete desulfurization. The desulfurization process and principle are also well known to those skilled in the art, so they will not be described in detail here.

[0056] a carbon dioxide absorption unit 2 connected to the water-washing desulfurization unit 1, comprising an absorption assembly 21 for absorbing carbon dioxide in the feed gas through a carbon dioxide absorbent, and a desorption assembly 22 connected to the absorption assembly 21 for releasing carbon dioxide in the carbon dioxide absorbent to obtain gaseous carbon dioxide. The absorption assembly 21 comprises a first absorption tower 210 and a second absorption tower 211, a nozzle 212 disposed at the top of the second absorption tower 211 for spraying the carbon dioxide absorbent, a moving assembly 213 connected to the nozzle 212 for controlling the vertical movement of the nozzle 212, and a rich liquid cooler 214 for cooling the absorbed carbon dioxide absorbent output from the first absorption tower 210; the first absorption tower 210 and the second absorption tower 211 are connected via a first pipeline 215;

[0057] In implementation, the moving component 213 can be an electric telescopic rod. The principle of the electric telescopic rod adjusting the nozzle for vertical movement is that the extension and contraction of the electric telescopic rod drives the nozzle to move in the vertical direction. The pipeline connected to the nozzle in the second absorption tower is a soft pipeline with good elasticity. The soft pipeline can be a rubber hose or a spring-protected hose.

[0058] In this embodiment, the absorption component 21 also includes an emptying water washing tower 216, which is connected to the second absorption tower 211 through a second pipeline 217, and is used to remove the carbon dioxide absorbent entrained in the raw gas after the carbon dioxide is removed to obtain a quasi-exhaust raw gas, and discharge the quasi-exhaust raw gas.

[0059] Specifically, the absorption state means being in the state of absorbing carbon dioxide; the carbon dioxide absorbent that has finished releasing is the carbon dioxide absorbent output by the analysis tower that has completed the carbon dioxide release process and absorbed the heat of the non-circulating absorption state carbon dioxide absorbent output by the first absorption tower.

[0060] a detection unit connected to the carbon dioxide absorption unit 2, for respectively detecting the carbon dioxide concentration, the gas rising speed at the gas inlet of the second absorption tower 211, the carbon dioxide absorption amount in the second absorption tower 211, the flow rate of the feed gas, and the flow rate of the carbon dioxide;

[0061] A control unit is respectively connected to the water washing desulfurization unit 1, the carbon dioxide absorption unit 2 and the detection unit, and is used to determine the pressure of the nozzle 212 and the vertical height of the nozzle 212 according to the gas rising speed and the carbon dioxide absorption amount, and to determine the temperature of the rich liquid cooler 214 according to the increase in the carbon dioxide concentration of the first absorption tower 210.

[0062] In this embodiment, the low-concentration carbon dioxide recovery and purification device further includes a compression adsorption unit 3, which is connected to the carbon dioxide absorption unit 2 and includes a dehumidification component 31 for removing moisture from the gaseous carbon dioxide and a drying component 32 for removing moisture from the gaseous carbon dioxide;

[0063] Among them, the dehumidification component 31 includes a dehumidifier connected end to end, a buffer tank for stabilizing the gas pressure fluctuation in the dehumidification component 31, a compressor for receiving the gas from the buffer tank and compressing it, and a high-pressure cold dryer for deeply dehumidifying the high-pressure and high-temperature gas output by the compressor. The drying component 32 is a drying bed skid.

[0064] Specifically, the compressor uses three stages of compression. After each stage, the gas enters the compressor's cooler for cooling with cooling water, then enters the compressor's water distributor for water separation before entering the next stage of compression. Pressure regulating valves are installed at the compressor outlet and the buffer tank inlet, controlling the pressure at 0.105 MPa to prevent the compressor from developing a vacuum.

[0065] The compressed mixed gas first passes through a high-pressure cold dryer to cool to 10°C, removing most of the water before entering the drying bed skid. The combined cooling and dehydration methods of the high-pressure cold dryer and the molecular sieve adsorption dehydration of the drying bed skid ensure the desired moisture content of the final product. This achieves superior process results and ensures higher quality than using the drying bed skid alone. Furthermore, since most of the condensed water is removed during the cooling and dehydration process, the dehydration load on the drying bed skid is reduced, minimizing the number of regenerations and saving regeneration energy.

[0066] In practice, the desiccant skid regeneration utilizes "zero-gas consumption" regeneration technology. This means that no carbon dioxide or foreign air is consumed during the desiccant skid regeneration process. The regeneration process consists of two phases: hot-blow and cold-blow. During the hot-blow phase, a blower directs air through an electric heater to heat the air before it enters the regenerated desiccant skid for heating. After the desiccant skid is heated, it enters the cold-blow phase for cooling. A blower draws cold air through the skid, removing heat from the skid before cooling it to room temperature in a cooler. The cooled air then enters the blower inlet and is re-cooled to the skid for cooling, thus recycling the air.

[0067] In this embodiment, the low-concentration carbon dioxide recovery and purification device further includes a freezing and liquefaction unit 4, which is connected to the compression adsorption unit 3 and is used to liquefy the gaseous carbon dioxide into liquid carbon dioxide, including a precooler, a condenser and a refrigeration unit.

[0068] Specifically, the mixed gas enters the precooler, exchanges heat with the condenser, and is cooled to 8°C before entering the condenser. Inside the condenser, it exchanges cold with the Freon refrigerant from the refrigeration unit and is cooled to -25°C. Simultaneously, the carbon dioxide component in the mixed gas liquefies into liquid carbon dioxide. The refrigeration unit uses a screw unit with Freon as the refrigerant, is equipped with a refrigerator economizer, and utilizes low-temperature barrel pump technology. As the refrigerant flows, the pressure drop in the pipelines causes the refrigerant to vaporize after the pressure in the pipeline drops below that of saturated vapor, wasting the refrigerant's cooling capacity. The use of a refrigerant economizer in conjunction with a low-temperature barrel pump increases the refrigerant's cooling efficiency by at least 10%. Furthermore, since the heat exchanger is filled with refrigerant, the heat exchange area occupied by vaporized gas is reduced, saving heat exchanger space.

[0069] Specifically, the absorption component 21 further includes:

[0070] a wire mesh demister 218 , which is disposed above the nozzle 212 and is used to eliminate bubbles generated by the combination of the carbon dioxide absorbent and the feed gas;

[0071] a first rich liquid pump 219 connected to the bottom of the first absorption tower 210 for pumping out the absorbed carbon dioxide absorbent at the bottom of the first absorption tower 210;

[0072] a rich liquid circulation pump 2110 , which is disposed between the first absorption tower 210 and the rich liquid cooler 214 and is used to circulate the absorbed carbon dioxide absorbent at the bottom of the first absorption tower 210 to the top of the first absorption tower 210 ;

[0073] a second rich liquid pump 2111 disposed between the first absorption tower 210 and the second absorption tower 211 for pumping the absorbed carbon dioxide absorbent at the bottom of the second absorption tower 211 to the top of the first absorption tower 210;

[0074] a lean liquid cooler 2112 , which is provided on a lean liquid delivery pipeline 2113 connected to the nozzle 212 , and is used to cool the carbon dioxide absorbent flowing through the lean liquid delivery pipeline 2113 after it has finished being released;

[0075] The filter 2114 is disposed between the lean liquid cooler 2112 and the nozzle 212 and connected to the lean liquid delivery pipeline 2113 , and is used to filter the carbon dioxide absorbent that has finished being released and flows through the lean liquid delivery pipeline 2113 .

[0076] Specifically, the parsing component 22 includes:

[0077] a lean-rich liquid heat exchanger 220 connected to the first rich liquid pump 219 via a rich liquid delivery pipeline 221 and to the lean liquid cooler 2112 via the lean liquid delivery pipeline 2113, for performing heat exchange between the carbon dioxide absorbent that has finished releasing and flows through the lean liquid delivery pipeline 2113 and the carbon dioxide absorbent in an absorbed state and flows through the rich liquid delivery pipeline 221;

[0078] a desorption tower 222 connected to the lean-rich liquid heat exchanger 220 via a rich liquid delivery pipeline 221, for releasing carbon dioxide from the carbon dioxide absorbent in an absorbed state to obtain gaseous carbon dioxide;

[0079] a lean liquid pump 223 connected to the bottom of the desorption tower 222 for pumping the carbon dioxide absorbent at the bottom of the desorption tower 222 into the lean liquid delivery pipeline 2113;

[0080] The gas output pipeline 224 is connected to the top of the analytical tower 222 for outputting the gaseous carbon dioxide.

[0081] Specifically, the detection unit includes:

[0082] A first carbon dioxide concentration sensor is provided in the air inlet passage of the cooling water washing tower 11 in the water washing desulfurization unit 1 to detect the carbon dioxide concentration before cooling water washing;

[0083] a second carbon dioxide concentration sensor, disposed in the gas output pipeline 224 and configured to detect the carbon dioxide concentration in the gas output pipeline 224;

[0084] a third carbon dioxide concentration sensor, disposed in the first absorption tower 210 , for detecting the carbon dioxide concentration in the first absorption tower 210 ;

[0085] a first gas flow sensor, which is arranged in the air inlet passage of the cooling water washing tower 11 in the water washing desulfurization unit 1 and is used to detect the flow rate of the raw gas flowing through the air inlet passage;

[0086] a second gas flow sensor, which is disposed in the gas output pipeline 224 and is used to detect the flow rate of carbon dioxide in the gas output pipeline 224;

[0087] an ultrasonic flow meter, which is provided at the gas inlet of the second absorption tower 211 and is used to detect the rising velocity of the raw gas at the gas inlet of the second absorption tower 211;

[0088] An online pH sensor is provided at the bottom of the second absorption tower 211 to detect the pH value of the carbon dioxide absorbent in the bottom of the second absorption tower 211 to determine the carbon dioxide absorption amount of the carbon dioxide absorbent.

[0089] Specifically, carbon dioxide (CO2) reacts with alkaline absorbents (such as NaOH, MEA, etc.) to produce carbonates or bicarbonates, resulting in a decrease in the pH value of the absorbent. The general reaction formula is: CO2 + 2OH - →CO3 2- +H2O or CO2+OH - →HCO3 - .

[0090] The initial pH of the alkaline absorbent is high (e.g. pH of NaOH solution is ≈ 13). As the CO2 absorption increases, the OH - is consumed, generating HCO3 - / CO3 2- The pH value gradually decreases (to 8-10). The pH change is quantitatively related to the amount of CO2 absorbed.

[0091] The pH sensor detects H in the absorbent through a glass electrode + Activity, convert the signal into pH value. Through the calibration curve or algorithm, the pH change is converted into CO2 absorption (mol / L), the formula is: Δ[CO2] ∝ (pH0- pH t ), where pH0 is the initial value, pH t It is a real-time value.

[0092] Specifically, the control unit is connected to the first carbon dioxide concentration sensor, the second carbon dioxide concentration sensor, the first gas flow sensor, and the second gas flow sensor to respectively obtain the carbon dioxide concentration before the cooling water washing, the carbon dioxide concentration of the gas output pipeline 224, the flow rate of the raw gas in the air intake channel, and the carbon dioxide flow rate of the gas output pipeline 224, determine the initial detection amount of carbon dioxide in the raw gas according to the carbon dioxide concentration before the cooling water washing and the flow rate of the raw gas in the air intake channel, determine the carbon dioxide output of the analysis component 22 according to the carbon dioxide concentration of the gas output pipeline 224 and the carbon dioxide flow rate of the gas output pipeline 224, and determine the recovery status of carbon dioxide according to the difference between the initial detection amount of carbon dioxide in the raw gas and the carbon dioxide output of the analysis component 22, wherein,

[0093] If the ratio of the difference to the initial detection amount is greater than or equal to the preset loss ratio, it is determined that the carbon dioxide recovery is abnormal, and the carbon dioxide concentration, the gas rising speed, the carbon dioxide absorption amount, the flow rate of the raw gas, and the flow rate of the carbon dioxide are collected to further determine the abnormal state;

[0094] If the ratio of the difference to the initial detection amount is less than the preset loss ratio, it is determined that the carbon dioxide recovery is normal.

[0095] Optionally, when the carbon dioxide absorption unit 2 is at a temperature of 30° C. to 50° C. and a pressure of 0.1 MPa to 0.3 MPa, the preset loss ratio may be in the range of [15%, 20%].

[0096] Preferably, in this embodiment, when the carbon dioxide absorption unit 2 is at a temperature of 30° C. to 50° C. and a pressure of 0.1 MPa to 0.3 MPa, the preset loss ratio is preferably 18%.

[0097] It can be understood by those skilled in the art that the preferred setting of 18% is a preferred embodiment when the carbon dioxide absorption unit 2 is at a temperature of 30°C to 50°C and a pressure of 0.1MPa to 0.3MPa. In actual application or implementation, those skilled in the art can adaptively adjust or replace the preset loss ratio according to changes in the temperature and pressure conditions of the carbon dioxide absorption unit 2.

[0098] During implementation, the control unit determines the recovery status of carbon dioxide based on the difference between the initial detection amount of carbon dioxide in the raw gas and the carbon dioxide output of the analysis component 22, and determines that the carbon dioxide recovery is abnormal based on the ratio of the difference to the initial detection amount being greater than or equal to a preset loss ratio. This solves the problem that the recovery and utilization rate of carbon dioxide is difficult to quantify and track, solves the problem that the decline in the recovery and utilization rate of carbon dioxide has not been identified for a long time, and improves the utilization rate of carbon dioxide recovery.

[0099] Specifically, the initial detection amount is the integral value of the product of the function of the carbon dioxide concentration relative to time and the function of the flow rate of the raw gas in the intake channel relative to time within a preset sampling period before the cooling water washing.

[0100] Specifically, the carbon dioxide output is the integral value of the product of the carbon dioxide concentration in the gas output pipeline as a function of time and the carbon dioxide flow rate in the gas output pipeline as a function of time within a preset sampling period.

[0101] Optionally, when the carbon dioxide absorption unit 2 is at a temperature of 30° C. to 50° C. and a pressure of 0.1 MPa to 0.3 MPa, the preset sampling period may be in the range of [10 min, 20 min].

[0102] Preferably, in this embodiment, when the carbon dioxide absorption unit 2 is at a temperature of 30° C. to 50° C. and a pressure of 0.1 MPa to 0.3 MPa, the preset sampling period is preferably 15 minutes.

[0103] It can be understood by those skilled in the art that the preferred setting of 15 minutes is a preferred embodiment when the carbon dioxide absorption unit 2 is at a temperature of 30°C to 50°C and a pressure of 0.1MPa to 0.3MPa. In actual application or implementation, those skilled in the art can adaptively adjust or replace the preset sampling period according to changes in the temperature and pressure conditions of the carbon dioxide absorption unit 2.

[0104] Specifically, the control unit is connected to the nozzle 212 and is used to further determine that the nozzle 212 is abnormal based on the gas rising speed being less than the first preset gas rising speed and the carbon dioxide absorption amount being greater than the preset carbon dioxide absorption amount, and increase the pressure of the nozzle 212.

[0105] Optionally, when the carbon dioxide absorption unit 2 is at a temperature of 30° C. to 50° C. and a pressure of 0.1 MPa to 0.3 MPa, the first preset gas rising speed may be in an optional range of [0.3 m / s, 0.5 m / s].

[0106] Preferably, in this embodiment, when the carbon dioxide absorption unit 2 is at a temperature of 30° C. to 50° C. and a pressure of 0.1 MPa to 0.3 MPa, the preferred embodiment of the first preset gas rising speed is 0.4 m / s.

[0107] It can be understood by those skilled in the art that the preferred setting of 0.4 m / s is a preferred embodiment when the carbon dioxide absorption unit 2 is at a temperature of 30°C to 50°C and a pressure of 0.1 MPa to 0.3 MPa. In actual application or implementation, those skilled in the art can adaptively adjust or replace the first preset gas rising speed according to changes in the temperature and pressure conditions of the carbon dioxide absorption unit 2.

[0108] Optionally, when the carbon dioxide absorption unit 2 is at a temperature of 30° C. to 50° C. and a pressure of 0.1 MPa to 0.3 MPa, the preset carbon dioxide absorption amount may be in an optional range of [0.25 kg / m³, 0.35 kg / m³].

[0109] Preferably, in this embodiment, when the carbon dioxide absorption unit 2 is at a temperature of 30° C. to 50° C. and a pressure of 0.1 MPa to 0.3 MPa, the preset carbon dioxide absorption amount is preferably 0.30 kg / m³.

[0110] It can be understood by those skilled in the art that the preferred setting of 0.30 kg / m³ is a preferred embodiment when the carbon dioxide absorption unit 2 is at a temperature of 30°C to 50°C and a pressure of 0.1 MPa to 0.3 MPa. In actual application or implementation, those skilled in the art can make adaptive adjustments or replacements to the preset carbon dioxide absorption amount according to changes in the temperature and pressure conditions of the carbon dioxide absorption unit 2.

[0111] In practice, when the carbon dioxide absorption unit 2 is at a temperature of 30°C to 50°C and a pressure of 0.1MPa to 0.3MPa, and the gas rising speed is less than the first preset gas rising speed by 0.1m / s and the carbon dioxide absorption amount is greater than the preset carbon dioxide absorption amount by 0.10kg / m³, the pressure of the nozzle 212 is adjusted to 1.1 times the current pressure of the nozzle 212; when the gas rising speed is less than the first preset gas rising speed by more than 0.1m / s, the pressure of the nozzle 212 is adjusted to the current pressure of the nozzle 212 for every 0.1m / s of excess. 12, and when the carbon dioxide absorption amount is greater than the preset carbon dioxide absorption amount by more than 0.10 kg / m³, the pressure of the nozzle 212 is adjusted to 1.1 times the current pressure of the nozzle 212 for every 0.10 kg / m³ that exceeds; for example, in a possible embodiment, the gas rising speed is less than the first preset gas rising speed by 0.2 m / s, and the carbon dioxide absorption amount is greater than the preset carbon dioxide absorption amount by 0.20 kg / m³. At this time, the pressure of the nozzle 212 is adjusted to 1.1×1.1×1.1=1.331 times the original pressure of the nozzle 212.

[0112] In practice, by further determining that the nozzle 212 is abnormal based on the fact that the gas rising speed is less than the first preset gas rising speed and the carbon dioxide absorption amount is greater than the preset carbon dioxide absorption amount, and increasing the pressure of the nozzle 212, the problem that the wire mesh demister 218 causes part of its metal powder to fall into the nozzle 212 under the impact of the raw gas, thereby causing the direction of the nozzle 212 to change, causing the nozzle 212 to spray carbon dioxide absorbent toward the gas inlet of the second absorption tower 211, hindering the raw gas from entering the second absorption tower 211, causing the entry speed of the raw gas to slow down, and then causing the raw gas and The vertical contact position of the carbon dioxide absorbent is offset downward. Since the vertical contact position between the raw gas and the carbon dioxide absorbent is offset downward, part of the carbon dioxide absorbent may have repolymerized, resulting in part of the raw gas leaving the second absorption tower 211 without contacting the carbon dioxide absorbent, resulting in the carbon dioxide not being completely absorbed into the carbon dioxide absorbent, resulting in the difference between the carbon dioxide output of the analytical component 22 and the initial detection amount of carbon dioxide in the raw gas within the preset sampling period and the proportion of the initial detection amount being greater than or equal to the preset loss proportion, thereby leading to the problem of low utilization rate of carbon dioxide recovery. By increasing the pressure of the nozzle 212 and thereby reducing the upward flow rate of the raw gas, the probability of part of the metal powder of the wire mesh demister 218 falling into the nozzle 212 due to the impact of the raw gas, resulting in a change in the direction of the nozzle 212, is reduced, thereby improving the utilization rate of carbon dioxide recovery.

[0113] Specifically, the control unit is connected to the moving component 213, and is used to further determine that the vertical height of the nozzle 212 is abnormal based on the fact that the gas rising speed is greater than or equal to the first preset gas rising speed and less than the second preset gas rising speed and based on the fact that the carbon dioxide absorption amount is less than or equal to the preset carbon dioxide absorption amount, and increase the vertical height of the nozzle 212 through the moving component 213.

[0114] Optionally, when the carbon dioxide absorption unit 2 is at a temperature of 30° C. to 50° C. and a pressure of 0.1 MPa to 0.3 MPa, the second preset gas rising speed may be in the range of [0.6 m / s, 1.0 m / s].

[0115] Preferably, in this embodiment, when the carbon dioxide absorption unit 2 is at a temperature of 30° C. to 50° C. and a pressure of 0.1 MPa to 0.3 MPa, the preferred embodiment of the second preset gas rising speed is 0.8 m / s.

[0116] It can be understood by those skilled in the art that the preferred setting of 0.8 m / s is a preferred embodiment when the carbon dioxide absorption unit 2 is at a temperature of 30°C to 50°C and a pressure of 0.1 MPa to 0.3 MPa. In actual application or implementation, those skilled in the art can adaptively adjust or replace the second preset gas rising speed according to changes in the temperature and pressure conditions of the carbon dioxide absorption unit 2.

[0117] In practice, when the carbon dioxide absorption unit 2 is at a temperature of 30°C to 50°C and a pressure of 0.1MPa to 0.3MPa, the gas rising speed is greater than or equal to the first preset gas rising speed and less than the second preset gas rising speed by 0.1m / s, and the carbon dioxide absorption amount is less than the preset carbon dioxide absorption amount by 0.10kg / m³, the vertical height of the nozzle 212 is adjusted to 1.2 times the vertical height of the current nozzle 212. When the carbon dioxide absorption amount is less than the preset carbon dioxide absorption amount by more than 0.10kg / m³, the vertical height of the nozzle 212 is adjusted to the current vertical height of the nozzle 212 for every 0.10kg / m³ that exceeds When the value of the gas rising speed being greater than or equal to the first preset gas rising speed and less than the second preset gas rising speed exceeds 0.1 m / s, the vertical height of the nozzle 212 is adjusted to 1.2 times the vertical height of the current nozzle 212 for every 0.1 m / s exceeding. For example, in a possible embodiment, the carbon dioxide absorption amount is less than the preset carbon dioxide absorption amount by 0.20 kg / m³, and the gas rising speed is greater than or equal to the first preset gas rising speed and less than the second preset gas rising speed by 0.2 m / s. At this time, the vertical height of the nozzle 212 is adjusted to 1.2×1.2×1.2=1.728 times the original vertical height of the nozzle 212.

[0118] In implementation, by obtaining the amount of carbon dioxide absorbed in the carbon dioxide absorbent in the second absorption tower 211, it is determined that the vertical height of the nozzle 212 is increased by the moving component 213 based on the fact that the gas rising speed is greater than or equal to the first preset gas rising speed and less than the second preset gas rising speed and based on the fact that the amount of carbon dioxide absorbed in the carbon dioxide absorbent in the second absorption tower 211 is less than or equal to the preset carbon dioxide absorption amount. The invention solves the problem that when part of the metal powder of the wire mesh demister 218 falls into the nozzle 212 under the impact of the raw gas, the direction of the nozzle 212 changes, and the nozzle 212 sprays the carbon dioxide absorbent toward the gas inlet of the second absorption tower 211, which hinders the raw gas from entering the second absorption tower 211, resulting in the entry speed of the raw gas being slowed down. At this time, part of the carbon dioxide absorbent has reached the bottom of the second absorption tower 211 without coming into contact with the raw gas. At this time, the raw gas leaves the second absorption tower 211 in large quantities during the time interval of the next carbon dioxide absorbent spraying by the nozzle 212, resulting in the carbon dioxide not being completely absorbed into the carbon dioxide absorbent, resulting in the difference between the carbon dioxide output of the analysis component 22 within the preset sampling period and the initial detection amount of carbon dioxide in the raw gas and the proportion of the initial detection amount being greater than or equal to the preset loss proportion, thereby resulting in the low utilization rate of carbon dioxide recovery. By increasing the vertical height of the nozzle 212 through the moving component 213, the time from the carbon dioxide absorbent being sprayed from the nozzle 212 to falling to the bottom of the second absorption tower 211 is increased, and the probability of the carbon dioxide absorbent contacting with the raw gas is increased, thereby avoiding the situation where the carbon dioxide absorbent reaches the bottom of the second absorption tower 211 without contacting the raw gas, and improving the utilization rate of carbon dioxide recovery.

[0119] Specifically, the control unit is connected to the rich liquid cooler 214, and is used to further determine that the temperature of the rich liquid cooler 214 is abnormal based on the increase in carbon dioxide concentration in the first absorption tower 210 being greater than the preset carbon dioxide concentration increase, and to reduce the temperature of the rich liquid cooler 214.

[0120] Optionally, when the carbon dioxide absorption unit 2 is at a temperature of 30°C to 50°C and a pressure of 0.1 MPa to 0.3 MPa, the preset carbon dioxide concentration increase can be in an optional range of [0.10 kg / m³, 0.20 kg / m³].

[0121] Preferably, in this embodiment, when the carbon dioxide absorption unit 2 is at a temperature of 30°C to 50°C and a pressure of 0.1MPa to 0.3MPa, the preset carbon dioxide concentration increase is preferably 0.15kg / m³.

[0122] It can be understood by those skilled in the art that the preferred setting of 0.15 kg / m³ is a preferred embodiment when the carbon dioxide absorption unit 2 is at a temperature of 30°C to 50°C and a pressure of 0.1 MPa to 0.3 MPa. In actual application or implementation, those skilled in the art can make adaptive adjustments or replacements to the preset carbon dioxide concentration increase according to changes in the temperature and pressure conditions of the carbon dioxide absorption unit 2.

[0123] In implementation, when the carbon dioxide absorption unit 2 is at a temperature of 30°C to 50°C and a pressure of 0.1MPa to 0.3MPa, when the increase in carbon dioxide concentration is greater than the preset increase in carbon dioxide concentration by within 0.03kg / m³, the temperature of the rich liquid cooler 214 is reduced by 0.5°C. When the increase in carbon dioxide concentration is greater than the preset increase in carbon dioxide concentration by more than 0.03kg / m³, the temperature of the rich liquid cooler 214 is reduced by 0.5°C for every 0.01kg / m³ that exceeds the preset increase in carbon dioxide concentration. For example, in a possible embodiment, the increase in carbon dioxide concentration is greater than the preset increase in carbon dioxide concentration by 0.05kg / m³, and at this time, the temperature of the rich liquid cooler 214 is reduced by 0.5°C+0.5°C+0.5°C=1.5°C.

[0124] In practice, the increase in carbon dioxide concentration in the first absorption tower 210 is obtained. If the increase in carbon dioxide concentration in the first absorption tower 210 is greater than a preset increase in carbon dioxide concentration, the density of the carbon dioxide absorbent is determined to be abnormal, and the temperature of the rich liquid cooler 214 is reduced. This solves the problem of increased viscosity of the carbon dioxide absorbent in the first absorption tower 210 due to absorption of carbon dioxide, which reduces the contact area between the carbon dioxide absorbent re-entering the first absorption tower 210 and the feed gas, weakening the carbon dioxide absorbent's ability to absorb carbon dioxide. This in turn causes carbon dioxide to be trapped in the first absorption tower 210 and difficult to be absorbed by the carbon dioxide absorbent. This, in turn, causes the difference between the carbon dioxide output of the analysis component 22 during a preset sampling period and the initial detected amount of carbon dioxide in the feed gas, and the ratio of the initial detected amount to be greater than or equal to a preset loss ratio, leading to low carbon dioxide recovery efficiency. By lowering the temperature of the rich liquid cooler 214, the temperature of the carbon dioxide absorbent re-entering the first absorption tower 210 is lower than the temperature of the raw gas entering the first absorption tower 210. When the two come into contact, the moisture in the raw gas is cooled to form partial moisture, which enters the carbon dioxide absorbent, reduces the viscosity of the carbon dioxide absorbent, increases the carbon dioxide absorption capacity of the carbon dioxide absorbent, and improves the efficiency of carbon dioxide recovery.

[0125] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

Claims

1. A low-concentration carbon dioxide recovery and purification device, characterized in that: include: Water washing and desulfurization unit, used to wash, cool and desulfurize the raw gas; a carbon dioxide absorption unit connected to the water-washing desulfurization unit, comprising an absorption assembly for absorbing carbon dioxide from the feed gas through a carbon dioxide absorbent, and a desorption assembly connected to the absorption assembly for releasing carbon dioxide from the carbon dioxide absorbent to obtain gaseous carbon dioxide, the absorption assembly comprising a first absorption tower and a second absorption tower, a nozzle disposed at the top of the second absorption tower for spraying the carbon dioxide absorbent, a movement assembly connected to the nozzle for controlling the vertical movement of the nozzle, and a rich liquid cooler for cooling the absorbed carbon dioxide absorbent output from the first absorption tower; a detection unit connected to the carbon dioxide absorption unit, for respectively detecting the carbon dioxide concentration, the gas rising speed at the gas inlet of the second absorption tower, the carbon dioxide absorption amount in the second absorption tower, the flow rate of the feed gas, and the flow rate of the carbon dioxide; A control unit is respectively connected to the water washing and desulfurization unit, the carbon dioxide absorption unit and the detection unit, and is used to determine the pressure and vertical height of the nozzle according to the gas rising speed and the carbon dioxide absorption amount, and to determine the temperature of the rich liquid cooler according to the increase in the carbon dioxide concentration of the first absorption tower.

2. The low-concentration carbon dioxide recovery and purification device according to claim 1, characterized in that: The absorbent assembly further comprises: a wire mesh demister, which is arranged above the nozzle and is used to eliminate bubbles generated by the combination of the carbon dioxide absorbent and the raw gas; a first rich liquid pump connected to the bottom of the first absorption tower, for pumping out the absorbed carbon dioxide absorbent at the bottom of the first absorption tower; a rich liquid circulation pump, disposed between the first absorption tower and the rich liquid cooler, for circulating the absorbed carbon dioxide absorbent at the bottom of the first absorption tower to the top of the first absorption tower; a second rich liquid pump, disposed between the first absorption tower and the second absorption tower, for pumping the carbon dioxide absorbent in the absorbed state at the bottom of the second absorption tower to the top of the first absorption tower; a lean liquid cooler, which is provided on the lean liquid conveying pipeline connected to the nozzle, and is used to cool the carbon dioxide absorbent flowing through the lean liquid conveying pipeline after the release; The filter is arranged between the lean liquid cooler and the nozzle, and is used to filter the carbon dioxide absorbent that has finished being released and flows through the lean liquid conveying pipeline.

3. The low-concentration carbon dioxide recovery and purification device according to claim 2, characterized in that: The parsing component includes: a lean-rich liquid heat exchanger connected to the first rich liquid pump via a rich liquid delivery pipeline and to the lean liquid cooler via the lean liquid delivery pipeline, for performing heat exchange between the carbon dioxide absorbent that has finished releasing and flows through the lean liquid delivery pipeline and the carbon dioxide absorbent in an absorbed state and flows through the rich liquid delivery pipeline; a desorption tower connected to the lean and rich liquid heat exchanger via a rich liquid delivery pipeline, for releasing carbon dioxide from the carbon dioxide absorbent in an absorbed state to obtain gaseous carbon dioxide; a lean liquid pump connected to the bottom of the desorption tower, for pumping the carbon dioxide absorbent at the bottom of the desorption tower that has finished being released into the lean liquid delivery pipeline; A gas output pipeline is connected to the top of the analytical tower and is used to output the gaseous carbon dioxide.

4. The low-concentration carbon dioxide recovery and purification device according to claim 3, characterized in that: The detection unit comprises: a first carbon dioxide concentration sensor, which is arranged in the air inlet passage of the cooling water washing tower in the water washing and desulfurization unit, and is used to detect the carbon dioxide concentration before the cooling water washing; a second carbon dioxide concentration sensor, which is arranged in the gas output pipeline and is used to detect the carbon dioxide concentration in the gas output pipeline; a third carbon dioxide concentration sensor, disposed in the first absorption tower, for detecting the carbon dioxide concentration in the first absorption tower; a first gas flow sensor, which is arranged in the air inlet passage of the cooling water washing tower in the water washing and desulfurization unit, and is used to detect the flow rate of the raw gas flowing through the air inlet passage; a second gas flow sensor, which is arranged in the gas output pipeline and is used to detect the flow rate of carbon dioxide in the gas output pipeline; an ultrasonic flow meter, which is provided at the gas inlet of the second absorption tower and is used to detect the gas rising velocity of the raw gas at the gas inlet of the second absorption tower; An online pH sensor is provided at the bottom of the second absorption tower, and is used to detect the pH value of the carbon dioxide absorbent in the bottom of the second absorption tower to determine the carbon dioxide absorption amount of the carbon dioxide absorbent.

5. The low-concentration carbon dioxide recovery and purification device according to claim 4, characterized in that: The control unit is connected to the first carbon dioxide concentration sensor, the second carbon dioxide concentration sensor, the first gas flow sensor, and the second gas flow sensor to respectively obtain the carbon dioxide concentration before the cooling water washing, the carbon dioxide concentration of the gas output pipeline, the flow rate of the raw gas in the air intake channel, and the carbon dioxide flow rate of the gas output pipeline; the initial detection amount of carbon dioxide in the raw gas is determined according to the carbon dioxide concentration before the cooling water washing and the flow rate of the raw gas in the air intake channel; the carbon dioxide output amount of the analysis component is determined according to the carbon dioxide concentration of the gas output pipeline and the carbon dioxide flow rate of the gas output pipeline; the recovery status of carbon dioxide is determined according to the difference between the initial detection amount of carbon dioxide in the raw gas and the carbon dioxide output amount of the analysis component, wherein, If the ratio of the difference to the initial detection amount is greater than or equal to the preset loss ratio, it is determined that the carbon dioxide recovery is abnormal, and the carbon dioxide concentration, the gas rising speed, the carbon dioxide absorption amount, the flow rate of the raw gas, and the flow rate of the carbon dioxide are collected to further determine the abnormal state; If the ratio of the difference to the initial detection amount is less than the preset loss ratio, it is determined that the carbon dioxide recovery is normal.

6. The low-concentration carbon dioxide recovery and purification device according to claim 5, characterized in that: The initial detection amount is the integral value of the product of the function of the carbon dioxide concentration relative to time and the function of the flow rate of the raw gas in the intake channel relative to time within a preset sampling period before the cooling water washing.

7. The low-concentration carbon dioxide recovery and purification device according to claim 6, characterized in that: The carbon dioxide output is an integral value of the product of a carbon dioxide concentration in the gas output pipeline as a function of time and a carbon dioxide flow rate in the gas output pipeline as a function of time within a preset sampling period.

8. The low-concentration carbon dioxide recovery and purification device according to claim 7, characterized in that: The control unit is connected to the nozzle, and is used to further determine that the nozzle is abnormal based on the gas rising speed being less than a first preset gas rising speed and the carbon dioxide absorption amount being greater than a preset carbon dioxide absorption amount, and increase the pressure of the nozzle.

9. The low-concentration carbon dioxide recovery and purification device according to claim 8, characterized in that: The control unit is connected to the moving component, and is used to further determine that the vertical height of the nozzle is abnormal based on the fact that the gas rising speed is greater than or equal to the first preset gas rising speed and less than the second preset gas rising speed and based on the fact that the carbon dioxide absorption amount is less than or equal to the preset carbon dioxide absorption amount, and increase the vertical height of the nozzle through the moving component.

10. The low-concentration carbon dioxide recovery and purification device according to claim 9, characterized in that: The control unit is connected to the rich liquid cooler, and is used to further determine that the temperature of the rich liquid cooler is abnormal based on the increase in carbon dioxide concentration in the first absorption tower being greater than a preset carbon dioxide concentration increase, and to reduce the temperature of the rich liquid cooler.

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