A device for recovering and purifying carbon dioxide from bio-fermentation tail gas

Abstract

The application relates to the tail gas treatment technical field and specifically discloses a biological fermentation tail gas carbon dioxide recovery and purification device, which comprises an absorption tower, a first filler layer and a first spraying assembly are arranged in the absorption tower; a desorption tower, a second filler layer and a second spraying assembly are arranged in the desorption tower; a first circulating pump is connected between the absorption tower and the second spraying assembly; a second circulating pump is connected between the desorption tower and the first spraying assembly; the first spraying assembly and the second spraying assembly both comprise a central pipe, a connecting pipe is rotationally connected to the central pipe, a liquid discharge pipe is connected to the connecting pipe, the liquid discharge pipe is provided with an outlet in a tangential direction of the connecting pipe, and a spraying head is further arranged on the liquid discharge pipe. The self-driven rotating spraying assembly is adopted, so that the dynamic and dead-angle-free uniform distribution of the absorbent in the tower is realized, the sealing leakage risk and the maintenance cost caused by external motor driving are eliminated, and the gas-liquid mass transfer efficiency is helped to be ensured.

Description

Technical Field

[0001] This application relates to the field of exhaust gas treatment technology, and in particular to a device for recovering and purifying carbon dioxide from bio-fermentation exhaust gas. Background Technology

[0002] The production process in the bio-fermentation industry generates a large amount of fermentation exhaust gas, which is rich in high concentrations of carbon dioxide. Recovering and purifying this carbon dioxide not only reduces greenhouse gas emissions, but also yields food-grade carbon dioxide with extremely high economic added value.

[0003] Currently, chemical or physical absorption methods are commonly used in industry to recover carbon dioxide from fermentation exhaust gases. This process generally relies on the coordinated operation of absorption and desorption towers: fermentation exhaust gases are usually purged by a fan or enter the absorption tower under their own pressure, where they are washed by a special absorbent to trap carbon dioxide; the carbon dioxide-rich absorbent is then pumped to the desorption tower, where purified carbon dioxide gas is released by heating or depressurization, and the depleted absorbent is then returned to the absorption tower, thus forming a recycling system.

[0004] To improve the capture efficiency of carbon dioxide in the absorption tower and the release efficiency in the desorption tower, a packing layer is usually installed inside the tower to increase the gas-liquid contact area, and a spray assembly is deployed above the packing layer to distribute the absorbent evenly from top to bottom. However, traditional spray assemblies mostly use fixed pipes and nozzles. Due to the obstruction of the packing layer and the turbulence of the gas flow from bottom to top, it is difficult for the absorbent sprayed at fixed positions to completely and evenly wet the entire packing cross-section. In areas of dense spraying, water tends to accumulate and directly penetrate the packing layer, while in areas of no spraying, the packing remains dry. This reduces the mass and heat transfer efficiency within the tower, resulting in a low carbon dioxide extraction rate from the fermentation tail gas and high energy consumption. Summary of the Invention

[0005] To address the aforementioned issues, this application provides a bio-fermentation tail gas carbon dioxide recovery and purification device.

[0006] The bio-fermentation tail gas carbon dioxide recovery and purification device provided in this application adopts the following technical solution: A bio-fermentation tail gas carbon dioxide recovery and purification device includes an absorption tower, wherein the absorption tower is provided with a first packing layer and a first spray assembly located on the side of the first packing layer near the top of the tower, the bottom of the absorption tower is used to contain an absorbent, and the bottom of the absorption tower is also provided with an inlet pipe for the fermentation tail gas to flow in. A desorption tower is provided with a second packing layer and a second spray assembly located on the side of the second packing layer near the top of the tower. The bottom of the desorption tower is used to contain the absorbent, and the top of the desorption tower is provided with an exhaust pipe for the treated gas to be discharged. The first circulating pump is connected between the bottom of the absorption tower and the second spray assembly; The second circulating pump is connected between the bottom of the desorption tower and the first spray assembly; Both the first spray assembly and the second spray assembly include: The central tube of the first spray assembly is connected to the top of the absorption tower, and the central tube of the second spray assembly is connected to the top of the desorption tower. A connecting pipe is rotatably connected to the central pipe; At least one drain pipe is connected to the connecting pipe, the drain pipe having an outlet arranged tangentially to the connecting pipe, such that the connecting pipe and the drain pipe rotate when the absorbent in the drain pipe is sprayed outward; the drain pipe is also provided with a spray head with an outlet facing the bottom of the tower.

[0007] By adopting the above technical solution, a spray head facing the bottom of the tower is installed on the drain pipe, so that part of the absorbent is sprayed downwards; another part of the absorbent is sprayed out from a tangentially set outlet. The reaction force generated drives the connecting pipe and the drain pipe to rotate, realizing self-driven spraying without the need for an external motor. This design not only eliminates the risk of air leakage and maintenance difficulties caused by the motor and sealing shaft at the top of the tower, but also allows the sprayed absorbent to better cover the entire packing layer, avoiding dead corners caused by fixed spraying, thus enhancing the gas-liquid contact effect inside the tower, thereby enhancing the absorption and desorption of carbon dioxide.

[0008] In addition, the desorption tower generates a dynamic water curtain as the absorbent is discharged through the rotating drain pipe, effectively integrating multiple functions. This water curtain forms a continuous dynamic barrier within the tower. Under centrifugal force, the water curtain causes droplets to collide at high speed with and forcefully break up foam in the rising gas, enhancing the separation efficiency of droplets and allowing for a more compact tower design. The water curtain eliminates the need for static filters and other physical media, thus eliminating the risk of frequent shutdowns for cleaning due to impurities and ensuring long-term continuous and stable operation of the unit. Crucially, this rotating water curtain, composed of cold absorbent, not only breaks up the foam when it comes into direct contact with the rising high-temperature gas but also simultaneously preheats the absorbent. This design cleverly couples the defoaming function and waste heat recovery function into the same process, improving the overall energy efficiency of the system.

[0009] Optionally, a heat exchanger is provided between the pipeline where the first circulating pump is located and the pipeline where the second circulating pump is located.

[0010] By adopting the above technical solution, the low-temperature rich solution output from the absorption tower and the high-temperature lean solution output from the desorption tower can exchange heat in a heat exchanger. This design utilizes the temperature difference of the circulating liquids within the system to achieve energy recovery and reuse. The rich solution is preheated before entering the desorption tower, reducing the additional energy consumption required for subsequent heating; the lean solution is cooled before returning to the absorption tower, which is more conducive to the absorption of carbon dioxide in the absorption tower. Therefore, the heat exchanger optimizes the thermal balance of the entire system and reduces energy consumption during operation.

[0011] Optionally, a recovery mechanism is also included, comprising a condenser, a compressor, and a collection tank. The input end of the condenser is connected to the exhaust pipe. The condenser is used to separate carbon dioxide and moisture from the gas discharged from the desorption tower. The output end of the condenser for discharging carbon dioxide is connected to the compressor, and the compressor is connected to the collection tank.

[0012] By employing the above technical solution, the high-temperature carbon dioxide gas released from the top of the desorption tower enters the condenser, where the water vapor is condensed and separated, thereby improving the purity of the carbon dioxide gas. Subsequently, the dried carbon dioxide gas is compressed by a compressor and stored in a collection tank for later storage or utilization. This complete recovery process ensures the high purity of the carbon dioxide product and achieves effective recovery of exhaust gas resources.

[0013] Optionally, a pretreatment mechanism may also be included, which includes a filter and a cooler disposed on the intake pipe.

[0014] By adopting the above technical solution, the fermentation exhaust gas entering the device first passes through a filter to remove solid impurities, protecting the subsequent first and second packing layers. Subsequently, the gas is cooled by a cooler; the lower temperature facilitates the capture of carbon dioxide by the absorbent. The pre-cooled gas enters from the bottom of the absorption tower, ensuring full contact with the absorbent flowing downwards, thus improving the efficiency of the initial absorption stage.

[0015] Optionally, each of the connecting pipes is provided with a fan blade on the side of the drain pipe near the top of the tower, so that the fan blade rotates together with the connecting pipe.

[0016] By adopting the above technical solution, the fan blades can rotate together with the connecting pipe. When the fan blades rotate, they force the rising airflow passing through them to rotate as well. At this time, because the small droplets entrained in the airflow are much denser and heavier than the gas, under the action of the centrifugal force of this high-speed rotation, the small droplets mixed with the gas will be thrown outward and separated, directly hitting the inner wall of the tower, thereby better removing the droplets entrained in the airflow. This design eliminates the drawbacks of traditional static wire mesh demisters that are prone to clogging and require regular cleaning, making it more convenient.

[0017] Optionally, the drain pipe includes a first pipe body and a second pipe body connected to the first pipe body; the first pipe body is connected to the connecting pipe and communicates with the interior of the connecting pipe, and the interior of the first pipe body is provided with a partition, the partition dividing the interior of the first pipe body into a first receiving cavity and a second receiving cavity, the first receiving cavity and the second receiving cavity are connected only at one end near the connecting pipe; the second pipe body is arranged tangentially along the central pipe, the first end of the second pipe body is connected to the first receiving cavity, and the second end of the second pipe body is used for the absorbent to be sprayed out; the spray head is connected to the second receiving cavity.

[0018] By adopting the above technical solution, the first receiving chamber is dedicated to supplying water to the tangential outlet, providing the power to drive the rotation; the second receiving chamber is dedicated to supplying water to the vertically downward spray head, achieving uniform liquid distribution. Therefore, by adding only one baffle, functional diversion can be achieved, ensuring the drainage pressure from the first receiving chamber to guarantee smooth rotation of the connecting pipe. More importantly, when multiple drainage pipes are installed, it ensures the symmetrical distribution of liquid mass within each drainage pipe, thereby solving the dynamic imbalance problem that may occur when the multi-functional arm rotates at high speed, ensuring the stability and reliability of the rotating structure's operation.

[0019] Optionally, the spray head is an atomizing spray head.

[0020] By employing the above technical solution, the atomizing nozzle can break the absorbent into a large number of fine droplets and then spray them out, increasing the surface area of ​​the liquid. When these droplets come into contact with the rising carbon dioxide gas, they provide more gas-liquid contact interfaces, thereby enhancing the mass transfer process and increasing the absorption and desorption rates of carbon dioxide.

[0021] Optionally, the outlet of the drain pipe is tapered.

[0022] By adopting the above technical solution, the tapered outlet increases the flow rate of the liquid ejected and enhances the reaction force generated by the liquid ejected from the tangential outlet. This provides a stronger driving torque for the rotation of the connecting pipe, helps to overcome fluid viscous resistance, and ensures that the rotation can be carried out continuously and stably under various working conditions.

[0023] Optionally, the drain pipe is provided in multiple sets, each set arranged in a ring at intervals, and the multiple sets of drain pipes are arranged at intervals along the axial direction of the central pipe.

[0024] By adopting the above technical solution, the multi-layered drainage pipe group arranged along the central pipe axis forms a multi-level rotating spray network, which enables the absorbent to be evenly distributed at different heights in the tower, forming a multi-step interception and washing of rising gas, further improving the sufficiency of gas-liquid contact and the utilization rate of the tower space.

[0025] Optionally, the length of the multiple sets of drain pipes increases sequentially from the side furthest from the top of the tower to the side closest to the top of the tower.

[0026] By adopting the above technical solution, the rising airflow carrying foam exhibits a flow characteristic of upward movement from the center and gradual diffusion towards the inner wall of the tower during diffusion within the tower. The shorter lower drain pipe intercepts the original high-concentration foam in the central area; while as the airflow diffuses outward and upward, the longer upper drain pipe can accurately intercept residual foam attempting to escape along the inner wall of the tower, thus achieving comprehensive coverage of the entire cross-section of the tower. The structure of a longer upper section and a shorter lower section ensures that the droplets ejected from the longer upper drain pipe fall along the outer edge, cleverly avoiding the core water curtain area of ​​the shorter lower drain pipe. This allows each water curtain layer to independently exert its strongest impact and cutting effect. Furthermore, at the same rotational speed, the longer the drain pipe, the greater the speed and force of the water jet at the end; the large, fragile foam at the bottom is broken by the water droplets ejected from the shorter drain pipe; while the small, stubborn foam that floats to the upper layer is broken by the water curtain formed by the droplets ejected from the longer drain pipe.

[0027] In summary, this application includes the following beneficial technical effects: 1. The self-driven rotating spray assembly enables dynamic and uniform distribution of the absorbent within the tower without dead angles, while eliminating the risk of sealing leakage and maintenance costs associated with external motor drive, thus helping to ensure gas-liquid mass transfer efficiency.

[0028] 2. By introducing fan blades, efficient dynamic defoaming and waste heat recovery pretreatment are achieved in the rotating spray zone. The functions of defoaming, preheating and distribution are combined into a single rotating structure, which simplifies the internal structure of the tower and improves working efficiency.

[0029] 3. The dual-chamber design with baffles inside the drain pipe ensures separation of the rotary drive and vertical spraying functions, while also giving the rotary structure good dynamic balance performance, thus ensuring stable operation and long service life under high-speed rotation. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall structure of the bio-fermentation tail gas carbon dioxide recovery and purification device according to an embodiment of this application; Figure 2 This is a cross-sectional view of a bio-fermentation tail gas carbon dioxide recovery and purification device according to an embodiment of this application; Figure 3 yes Figure 2 A magnified view of a portion of point A in the middle; Figure 4 This is a schematic diagram of the structure of the second spray component in the bio-fermentation tail gas carbon dioxide recovery and purification device according to an embodiment of this application; Figure 5 yes Figure 4 A magnified view of a portion of point B in the middle.

[0031] Reference numerals: 1. Absorption tower; 11. First packing layer; 12. Inlet pipe; 13. Outlet pipe; 131. Regulating valve; 2. First spray assembly; 3. Desorption tower; 31. Second packing layer; 32. Exhaust pipe; 33. Heating element; 4. Second spray assembly; 41. Central pipe; 42. Connecting pipe; 421. Fan blade; 43. Drain pipe; 431. First pipe body; 4311. Baffle; 4312. First receiving cavity; 4313. Second receiving cavity; 432. Second pipe body; 44. Spray head; 5. First circulating pump; 6. Second circulating pump; 7. Heat exchanger; 8. Recovery mechanism; 81. Condenser; 82. Compressor; 83. Collection tank; 9. Pretreatment mechanism; 91. Filter; 92. Cooler; 10. Rotary sealing joint. Detailed Implementation

[0032] The following combination Figures 1-5 This application will be described in further detail.

[0033] This application discloses a device for recovering and purifying carbon dioxide from bio-fermentation tail gas. (Refer to...) Figure 1 The bio-fermentation tail gas carbon dioxide recovery and purification device includes an absorption tower 1 and a desorption tower 3. In this embodiment, the absorption tower 1 and the desorption tower 3 are arranged vertically in the height direction as an example for illustration.

[0034] Reference Figure 2 The absorption tower 1 contains a first packing layer 11, above which is a first spray assembly 2, installed at the top of the absorption tower 1. Below the first packing layer 11, a cavity is provided inside the absorption tower 1 for storing the absorbent, which is an aqueous solution of an alcohol amine or an alkaline solution. The absorbent is used to absorb carbon dioxide from the fermentation exhaust gas to achieve preliminary separation of carbon dioxide. An inlet pipe 12 is also provided at the bottom of the absorption tower 1 for the fermentation exhaust gas to flow into, located below the first packing layer 11. An outlet pipe 13 is provided at the top of the absorption tower 1, and a regulating valve 131 is installed on the outlet pipe 13, allowing the absorbed gas in the absorption tower 1 to be discharged in a timely manner.

[0035] The desorption tower 3 has a second packing layer 31 inside, and a second spray assembly 4 is provided above the second packing layer 31, which is installed at the top of the desorption tower 3. A cavity for storing the absorbent is provided below the second packing layer 31 inside the desorption tower 3. A heating element 33, which is a heating coil, is provided at the bottom of the desorption tower 3; in other embodiments, the heating element 33 may also be a heating wire. The heating element 33 is used to heat the absorbent at the bottom of the desorption tower 3, thereby reducing the solubility of carbon dioxide in the absorbent and releasing the carbon dioxide from the absorbent more quickly. An exhaust pipe 32 is provided at the top of the desorption tower 3 for discharging the treated gas.

[0036] Absorption tower 1 and desorption tower 3 are connected by a liquid circulation pipeline. A first circulation pump 5 is installed on the pipeline connecting the bottom of absorption tower 1 to the second spray assembly 4. The first circulation pump 5 pumps the carbon dioxide-rich solution from the bottom of absorption tower 1 to the second spray assembly 4 at the top of desorption tower 3, and then sprays it out through the second spray assembly 4. A second circulation pump 6 is installed on the pipeline connecting the bottom of desorption tower 3 to the first spray assembly 2. The second circulation pump 6 pumps the low-carbon dioxide solution from the bottom of desorption tower 3 to the first spray assembly 2 at the top of absorption tower 1, and then sprays it out through the first spray assembly 2. Both the rich and lean solutions are absorbents, differing only in their internal carbon dioxide content. Therefore, under the action of the first circulation pump 5 and the second circulation pump 6, the absorbents in absorption tower 1 and desorption tower 3 can circulate.

[0037] The first circulating pump 5 is installed on the outside of the absorption tower 1, and the second circulating pump 6 is installed on the outside of the desorption tower 3. The input ends of the first circulating pump 5 and the second circulating pump 6 are both located below the liquid level inside the corresponding tower body to ensure normal liquid transport.

[0038] In the absorption tower 1, the gas to be treated flows in from the bottom of the absorption tower 1 and flows upward. The first spray assembly 2 sprays the lean liquid with a low carbon dioxide content downward, so that the lean liquid can fall more evenly into the first packing layer 11. The lean liquid comes into full contact with the fermentation tail gas to be treated in the first packing layer 11, and absorbs the carbon dioxide in the fermentation tail gas into the absorbent. Then the carbon dioxide content in the absorbent increases, so that the lean liquid becomes rich liquid, and the rich liquid falls to the bottom of the absorption tower 1.

[0039] In desorption tower 3, under internal heating, carbon dioxide in the absorbent at the bottom of desorption tower 3 is released and flows upward. The second spray assembly 4 sprays the rich liquid with a high carbon dioxide content downward. The rich liquid comes into full contact with the carbon dioxide in the second packing layer 31. Due to the high temperature, the rich liquid will not continue to absorb carbon dioxide, but will instead release the carbon dioxide, thereby further increasing the content of gaseous carbon dioxide in desorption tower 3. The carbon dioxide is then discharged through the exhaust pipe 32 at the top of desorption tower 3. At this time, the rich liquid in the second packing layer 31 becomes lean liquid, and the lean liquid falls to the bottom of desorption tower 3.

[0040] A heat exchanger 7 is installed between the pipelines containing the first circulating pump 5 and the second circulating pump 6. The low-temperature rich liquid flowing out of the absorption tower 1 and the high-temperature lean liquid flowing out of the desorption tower 3 cross-flow in the heat exchanger 7, exchanging heat. The rich liquid is preheated, and the lean liquid is cooled, thereby achieving efficient recovery and reuse of energy within the system.

[0041] Reference Figure 2 , Figure 3 and Figure 4 The first spray assembly 2 and the second spray assembly 4 have the same structure. The structure of the second spray assembly 4 will be used as an example for explanation. The second spray assembly 4 includes a vertically arranged central pipe 41, which is fixedly installed on the top of the desorption tower 3. The top end of the central pipe 41 is located outside the desorption tower 3, and the bottom end is located inside the desorption tower 3. The bottom end of the central pipe 41 is connected to a freely rotatable connecting pipe 42 via a rotary sealing joint 10, allowing the connecting pipe 42 to rotate relative to the central pipe 41. A support frame (not shown in the figure) can also be fixedly installed on the inner wall of the desorption tower 3, allowing the connecting pipe 42 to be rotatably connected to the support frame, thereby providing better support for the connecting pipe 42 and ensuring the normal operation of the rotating part.

[0042] Several drain pipes 43 extend outward from the side wall of the connecting pipe 42; multiple drain pipes 43 are arranged in a circumferential array. One end of the drain pipe 43 is connected to the interior of the connecting pipe 42, and the other end of the drain pipe 43 is open, with the opening of the drain pipe 43 tangential to the connecting pipe 42. Therefore, when the absorbent in the central pipe 41 flows into the connecting pipe 42, it can continue to flow into the drain pipe 43. Then, the absorbent in the drain pipe 43 is sprayed outward along the tangentially arranged opening, which generates a tangential reaction force. This reaction force pushes the connecting pipe 42, along with all the drain pipes 43, to rotate around the axis of the central pipe 41. Multiple spray heads 44 are also provided on the drain pipe 43. The spray heads 44 are atomizing nozzles. The input end of the spray head 44 is connected to the inside of the drain pipe 43, and the output end of the spray head 44 faces downward. Therefore, the spray head 44 can rotate together with the drain pipe 43, thereby expanding the spray range and allowing the falling absorbent to come into more full contact with the second packing layer 31, thus enhancing the gas-liquid mass transfer effect.

[0043] The aforementioned structure not only enables rotating spraying, expanding the spray range, but also allows the continuously sprayed absorbent from the rotating drain pipe 43 to form a dynamic water curtain barrier within the desorption tower 3. When carbon dioxide gas containing foam rises through this water curtain, the high-speed droplets collide violently with the foam. During this process, the foam is broken up by the droplets and forcibly separated from the gas. The separated liquid components are then carried back to the bottom of the tower by the water curtain or by their own gravity. This process achieves highly efficient defoaming, avoiding the clogging risk associated with using static wire mesh demisters.

[0044] The outlet at the end of the drain pipe 43 is tapered, which accelerates the flow of internal liquid during the discharge process and enhances the reaction force used to drive the connecting pipe 42 to rotate.

[0045] Furthermore, multiple sets of drain pipes 43 are provided; in this embodiment, two sets of drain pipes 43 are provided, and the two sets of drain pipes 43 are arranged at intervals in the vertical direction. The length of the lower drain pipe 43 is less than the length of the upper drain pipe 43, so the water curtain formed by the liquid sprayed by the rotating drain pipe 43 has different coverage ranges.

[0046] The advantages of this design are twofold: First, it rationally distributes the water distribution area across the drain pipes 43 at different heights, avoiding water flow interference caused by concentrated spraying at the same height, resulting in a more uniform distribution. Second, this multi-layered water curtain, unfolding in an inverted cone shape, better matches the gas's movement trajectory from bottom to top and gradually towards the edges within the tower. This ensures that the rising airflow is thoroughly covered by the corresponding water curtain at different heights, extending the gas-liquid contact time and further improving the washing, absorption, and desorption efficiency of carbon dioxide. Furthermore, the multiple water curtains increase the probability of gas-liquid collision, thereby further enhancing the defoaming effect.

[0047] A fan blade 421 is fixedly installed on the connecting pipe 42 above the drain pipe 43. Multiple fan blades 421 are arranged in a circular array. When the connecting pipe 42 rotates, the fan blades 421 rotate synchronously. The blade angle of attack of the fan blade 421 follows the spin direction formed by the tangential backlash of the fluid, acting as a swirling separation guide plate during rotation, coordinating with the forced upward airflow to change direction and generate centrifugal vortices. Therefore, the rotation of the fan blade 421 causes the upward airflow to rotate, and the foam entrained in the rotating airflow can be thrown outward under the action of centrifugal force, thereby further enhancing the separation effect of foam entrained in the airflow. In addition, in the desorption tower 3, the cold, rich liquid droplets sprayed from the spray head 44 can collide and mix with the rising high-temperature gas in this area, causing the rich liquid droplets to be partially heated, realizing the recovery and utilization of waste heat in the airflow.

[0048] Reference Figure 4 and Figure 5 Furthermore, the drain pipe 43 includes a first pipe body 431 and a second pipe body 432. The first pipe body 431 is arranged radially along the connecting pipe 42. One end of the first pipe body 431 communicates with the interior of the connecting pipe 42, and the other end of the first pipe body 431 is closed, allowing the absorbent in the connecting pipe 42 to enter the interior of the first pipe body 431. A partition 4311 is provided inside the first pipe body 431. Both sides of the partition 4311 are fixedly connected to the inner wall of the first pipe body 431. The end of the partition 4311 away from the connecting pipe 42 abuts against the inner wall of the end of the first pipe body 431, and the end of the partition 4311 near the connecting pipe 42 and the inner wall of the end of the first pipe body 431 are spaced apart. Therefore, the partition 4311 can divide the inner cavity of the first pipe body 431 into a first receiving cavity 4312 and a second receiving cavity 4313, and the first receiving cavity 4312 and the second receiving cavity 4313 are connected only at the end near the connecting pipe 42.

[0049] The second tube 432 is arranged tangentially to the central tube 41. One end of the second tube 432 is connected to the end of the first tube 431 away from the connecting tube 42, and the second tube 432 communicates with the first receiving cavity 4312. The other end of the second tube 432 is provided with a tapered opening, so that the internal liquid can provide rotational power when it is sprayed outward. The spray head 44 is fixedly installed on the outer wall of the bottom of the drain pipe 43, and the input end of the spray head 44 communicates with the second receiving cavity 4313.

[0050] Therefore, the liquid entering the drain pipe 43 naturally splits at the inlet near the connecting pipe 42. One part enters the first receiving chamber 4312 and then flows to the tangential outlet to provide power; the other part enters the second receiving chamber 4313 and then flows to the spray head 44 to achieve liquid distribution. This structure ensures that the liquid weight in each drain pipe 43 is consistent, providing higher dynamic balance performance for the entire rotating part, and ensuring smooth and reliable operation.

[0051] To achieve a better spraying effect, the drain pipes 43 can be multi-layered. In this embodiment, multiple sets of drain pipes 43 are installed at intervals along the axial direction of the central pipe 41, each set consisting of multiple drain pipes 43 arranged in a ring at intervals. The multiple layers of drain pipes 43 form a three-dimensional spray network. The overhang length of the multiple drain pipes 43 increases sequentially from bottom to top. In this way, the spray coverage gradually expands from bottom to top, forming a gradient distribution that matches the gas diffusion pattern, further increasing the gas-liquid contact area.

[0052] Reference Figure 2 To better recover carbon dioxide from the fermentation exhaust gas, the device also includes a pretreatment unit 9 and a recovery unit 8. The pretreatment unit 9 includes a filter 91 and a cooler 92, both of which are installed on the inlet pipe 12. The fermentation exhaust gas first passes through the filter 91 to remove impurities, then passes through the cooler 92 to cool down, and then enters from the bottom of the absorption tower 1, where it comes into countercurrent contact with the absorbent flowing from top to bottom, thus beginning the carbon dioxide absorption process.

[0053] The recovery mechanism 8 includes a condenser 81, a compressor 82, and a collection tank 83. The input end of the condenser 81 is connected to the exhaust pipe 32 at the top of the desorption tower 3. The condenser 81 has two output ends: one for discharging separated moisture and the other for discharging separated carbon dioxide. The output end of the condenser 81 for discharging carbon dioxide is connected to the input end of the compressor 82, and the output end of the compressor 82 is connected to the collection tank 83. The high-humidity carbon dioxide gas released from the top of the desorption tower 3 enters the condenser 81, where the moisture is condensed and separated. The dry carbon dioxide gas is then compressed by the compressor 82 and stored in the collection tank 83, completing the recovery and storage of high-purity carbon dioxide.

[0054] The implementation principle of the bio-fermentation tail gas carbon dioxide recovery and purification device in this application embodiment is as follows: After pretreatment by impurity removal and cooling, the fermentation tail gas enters from the bottom of the absorption tower 1 and comes into countercurrent contact with the absorbent that is uniformly sprayed down through the first spray assembly 2. Carbon dioxide is captured by the absorbent to form a rich liquid, which falls to the bottom of the absorption tower 1. The rich liquid at the bottom of the absorption tower 1 is pumped to the second spray assembly 4 at the top of the desorption tower 3. The second spray assembly 4 sprays the rich liquid downwards uniformly. The lean liquid at the bottom of the desorption tower 3 releases carbon dioxide gas under heating conditions. The carbon dioxide gas moves upward and comes into countercurrent contact with the falling rich liquid. Then, the carbon dioxide gas is discharged through the exhaust pipe 32 at the top of the desorption tower 3. The lean liquid at the bottom of the desorption tower 3 is pumped back to the first spray assembly 2 at the top of the absorption tower 1 for reuse. The carbon dioxide gas discharged from the desorption tower 3 is recovered after condensation and compression.

[0055] Throughout the process, the first spray assembly 2 and the second spray assembly 4 utilize the liquid's own energy to achieve uniform liquid distribution. They also integrate defoaming and preheating functions, further ensuring the quality of the recycled products and the system's low energy consumption.

[0056] The above are optional embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made to the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A bio-fermentation tail gas carbon dioxide recovery and purification device, characterized in that, include: An absorption tower (1) is provided with a first packing layer (11) and a first spray assembly (2) located on the side of the first packing layer (11) near the top of the tower. The bottom of the absorption tower (1) is used to contain the absorbent. The bottom of the absorption tower (1) is also provided with an air inlet pipe (12) for the fermentation tail gas to flow in. The desorption tower (3) is provided with a second packing layer (31) and a second spray assembly (4) located on the side of the second packing layer (31) near the top of the tower. The bottom of the desorption tower (3) is used to contain the absorbent, and the top of the desorption tower (3) is provided with an exhaust pipe (32) for the treated gas to be discharged. The first circulating pump (5) is connected between the bottom of the absorption tower (1) and the second spray assembly (4); The second circulating pump (6) is connected between the bottom of the desorption tower (3) and the first spray assembly (2); Both the first spray assembly (2) and the second spray assembly (4) include: The central tube (41) of the first spray assembly (2) is connected to the top of the absorption tower (1), and the central tube (41) of the second spray assembly (4) is connected to the top of the desorption tower (3). Connecting pipe (42) is rotatably connected to the central pipe (41); At least one drain pipe (43) is connected to the connecting pipe (42), the drain pipe (43) having an outlet arranged tangentially to the connecting pipe (42) so that the connecting pipe (42) and the drain pipe (43) rotate when the absorbent in the drain pipe (43) is sprayed outward; the drain pipe (43) is also provided with a spray head (44) with an outlet facing the bottom of the tower.

2. The bio-fermentation tail gas carbon dioxide recovery and purification device according to claim 1, characterized in that: A heat exchanger (7) is provided between the pipeline where the first circulating pump (5) is located and the pipeline where the second circulating pump (6) is located.

3. The bio-fermentation tail gas carbon dioxide recovery and purification device according to claim 1, characterized in that: It also includes a recycling mechanism (8), which includes a condenser (81), a compressor (82) and a collection tank (83). The input end of the condenser (81) is connected to the exhaust pipe (32). The condenser (81) is used to separate carbon dioxide and moisture from the gas discharged from the desorption tower (3). The output end of the condenser (81) for discharging carbon dioxide is connected to the compressor (82). The compressor (82) is connected to the collection tank (83).

4. The bio-fermentation tail gas carbon dioxide recovery and purification device according to claim 1, characterized in that: It also includes a pretreatment mechanism (9), which includes a filter (91) and a cooler (92) disposed on the air intake pipe (12).

5. The bio-fermentation tail gas carbon dioxide recovery and purification device according to claim 1, characterized in that: Each of the connecting pipes (42) is provided with a fan blade (421) on the side of the drain pipe (43) near the top of the tower, so that the fan blade (421) rotates together with the connecting pipe (42).

6. The bio-fermentation tail gas carbon dioxide recovery and purification device according to claim 1, characterized in that: The drain pipe (43) includes a first pipe body (431) and a second pipe body (432) connected to the first pipe body (431); the first pipe body (431) is connected to the connecting pipe (42) and communicates with the interior of the connecting pipe (42); the interior of the first pipe body (431) is provided with a partition (4311), the partition (4311) divides the interior of the first pipe body (431) into a first receiving cavity (4312) and a second receiving cavity (4313), the first receiving cavity (4312) and the second receiving cavity (4313) are connected only at one end near the connecting pipe (42); the second pipe body (432) is arranged tangentially along the central pipe (41), the first end of the second pipe body (432) is connected to the first receiving cavity (4312), and the second end of the second pipe body (432) is used for the absorbent to be sprayed out; the spray head (44) is connected to the second receiving cavity (4313).

7. The bio-fermentation tail gas carbon dioxide recovery and purification device according to claim 1, characterized in that: The spray head (44) is an atomizing nozzle.

8. The bio-fermentation tail gas carbon dioxide recovery and purification device according to claim 1, characterized in that: The outlet of the drain pipe (43) is tapered.

9. The bio-fermentation tail gas carbon dioxide recovery and purification device according to claim 1, characterized in that: The drain pipe (43) is provided in multiple sets, each set is arranged in a ring at intervals, and the multiple sets of drain pipes (43) are arranged at intervals along the axial direction of the central pipe (41).

10. The bio-fermentation tail gas carbon dioxide recovery and purification device according to claim 9, characterized in that: The length of the multiple sets of drain pipes (43) increases sequentially from the side furthest from the top of the tower to the side closest to the top of the tower.

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