A high-efficiency carbon dioxide gas decomposing device

Abstract

The application relates to the technical field of carbon dioxide conversion, and provides a high-efficiency carbon dioxide gas decomposition device which comprises a first pipe body, a second pipe body, a metal electrode and a carbon bed; the first pipe body and the second pipe body are both made of insulating materials, the second pipe body is sleeved on the first pipe body, a gap is left between the outer wall of the first pipe body and the inner wall of the second pipe body, a first gas inlet and a first gas outlet which are in communication with the gap are arranged on the second pipe body; the metal electrode is sleeved on the second pipe body, the metal electrode is used for being connected with a high-voltage power supply and serving as a discharging anode, a circulating solution is arranged in the first pipe body, and the solution in the first pipe body is used as a grounding electrode and a cooling element; the carbon bed is arranged at the first gas outlet, and the carbon bed is used for decomposing complex gas output by the first gas outlet again. The first pipe body, the second pipe body, the metal electrode and the carbon bed are used in cooperation, carbon dioxide is decomposed twice, and the carbon dioxide decomposition efficiency is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide conversion technology, and more specifically, to a highly efficient carbon dioxide gas decomposition device. Background Technology

[0002] Carbon dioxide (CO2), as a abundant, safe, inexpensive, and readily available renewable resource, can be chemically converted to obtain high-value-added energy, materials, and chemical products. Therefore, research on the activated conversion of CO2 has always been a hot topic, encompassing various fields of modern chemical synthesis, including fine chemicals, bulk chemistry, drug development, and bio-based polymers. However, research has revealed that CO2 often exhibits thermodynamic stability and relative kinetic inertness during its chemical conversion, and the products from CO2 chemical conversion are structurally limited and have low conversion efficiency.

[0003] Traditional CO2 thermal decomposition methods not only require harsh reaction conditions but also have low energy efficiency, necessitating the development of novel technologies to improve CO2 conversion efficiency. In recent years, several conversion methods have been developed, including photocatalysis, electrocatalysis, photoelectric reduction, and plasma conversion, all demonstrating promising application prospects. Among these, plasma conversion, due to its high catalytic efficiency and mild reaction conditions, is considered a strong alternative to pyrolysis.

[0004] Plasma is a physical state rich in various highly reactive species, including ions, electrons, excited-state atoms and molecules, and free radicals. These reactive particles can participate in a variety of chemical reactions. High-energy particles in low-temperature plasmas typically possess energies of several to tens of electron volts, sufficient to overcome the activation energies of many chemical reactions. Furthermore, the non-equilibrium characteristics of low-temperature plasmas result in electron temperatures far exceeding those of heavy particles. This non-equilibrium state can significantly promote chemical reactions, overcoming the limitations imposed by thermodynamic equilibrium on reaction pathways. Therefore, high-energy particles generated through methods such as gas discharge can decompose carbon dioxide into carbon monoxide and oxygen, achieving efficient carbon dioxide conversion and providing a new technological pathway for its resource utilization.

[0005] In technologies related to the plasma-based decomposition of carbon dioxide, common methods to improve gas conversion efficiency include optimizing the material and morphology of the high-voltage electrode, adjusting the gas inlet rate, controlling the reaction environment temperature, and introducing adsorbent materials. These methods primarily achieve their effects by altering external conditions. However, these approaches have relatively limited impact on improving carbon dioxide conversion efficiency. Furthermore, the generated oxygen typically requires further purification, increasing process complexity and cost. Summary of the Invention

[0006] The problem addressed by this invention is how to improve the efficiency of carbon dioxide decomposition.

[0007] To address the above problems, the present invention provides a high-efficiency carbon dioxide gas decomposition device, comprising a first tube, a second tube, a metal electrode, and a carbon bed;

[0008] Both the first tube and the second tube are made of insulating material. The second tube is sleeved on the first tube. A sealed gap is left between the outer wall of the first tube and the inner wall of the second tube. The second tube is provided with a first air inlet and a first air outlet that communicate with the gap.

[0009] The metal electrode is sleeved on the second tube body, and the metal electrode is used to connect to a high-voltage power supply and serve as a discharge positive electrode. The first tube body is used to house a circulating solution, and the solution in the first tube body serves as a grounding electrode and a cooling function.

[0010] The carbon bed is disposed at the first gas outlet, and the carbon bed is used to further decompose the gas output from the first gas outlet.

[0011] Optionally, the carbon bed includes a reaction chamber, a silo, and a heating element. The reaction chamber is provided with a second air inlet and a second air outlet. The second air inlet is connected to the first air outlet, and the second air outlet is used to connect to a detection device. The silo is connected to the reaction chamber and is used to store activated carbon and transport the activated carbon to the reaction chamber. The heating element is disposed inside the reaction chamber.

[0012] Optionally, the silo has a funnel-shaped structure, with the small opening of the funnel-shaped structure communicating with the reaction chamber, and a sealing cover detachably connected to the large opening of the funnel-shaped structure.

[0013] Optionally, multiple heating elements are provided, and the multiple heating elements are arranged alternately in the reaction chamber.

[0014] Optionally, the carbon bed further includes a temperature control system connected to the heating element for acquiring and adjusting the temperature of the heating element.

[0015] Optionally, the first tube, the second tube, and the metal electrode are coaxially arranged with each other.

[0016] Optionally, the two ends of the first tube extend out from the two ends of the second tube, respectively.

[0017] Optionally, both the first tube and the second tube are quartz glass tubes.

[0018] Optionally, a catalyst is filled between the outer wall of the first tube and the inner wall of the second tube.

[0019] Optionally, the first air inlet and the first air outlet are respectively located at both ends of the second pipe.

[0020] The beneficial effects of the high-efficiency carbon dioxide gas decomposition device of the present invention are as follows: both the first tube and the second tube are made of insulating material. The second tube is sleeved on the first tube, and a gap is left between them. Carbon dioxide gas can be introduced through the first inlet on the second tube and discharged through the first outlet. The metal electrode is sleeved on the second tube and is used to connect to a high-voltage power supply and serve as the positive electrode for discharge. A circulating solution is placed inside the first tube and serves as a grounding electrode. Thus, the aqueous solution, the first tube, the second tube, and the metal electrode form a plasma discharge region. When the high-voltage power supply is turned on and carbon dioxide gas is introduced into the gap between the first tube and the second tube through the first inlet, the carbon dioxide gas undergoes initial decomposition, forming a complex gas mixed with carbon dioxide, oxygen, carbon monoxide, and oxygen ions, which is discharged through the first outlet. During the initial decomposition of carbon dioxide, the metal electrode is externally placed, and the low-temperature solution circulating inside the first tube continuously cools the gas, which can better control the temperature of the high-efficiency carbon dioxide gas decomposition device and thus improve the carbon dioxide conversion rate. The carbon bed is connected to the first gas outlet. The complex gas obtained after gas decomposition enters the carbon bed through the first gas outlet. The complex gas is further decomposed in the carbon bed using a catalyst (such as activated carbon). A large amount of oxygen is consumed, and the carbon monoxide content increases, forming a mixed gas mainly composed of carbon dioxide and carbon monoxide. This effectively improves the conversion rate of carbon dioxide and reduces the complexity of the converted gas. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the high-efficiency carbon dioxide gas decomposition device according to an embodiment of the present invention;

[0022] Figure 2 This is a schematic cross-sectional view of the high-efficiency carbon dioxide gas decomposition device according to an embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of the carbon bed and temperature control system according to an embodiment of the present invention.

[0024] Explanation of reference numerals in the attached figures:

[0025] 1-The first tube body;

[0026] 2-Second pipe body; 21-First air inlet; 22-First air outlet;

[0027] 3-Metal electrode;

[0028] 4-Carbon bed; 41-Reaction chamber; 411-Second air inlet; 412-Second air outlet; 42-Bag; 421-Sealing ring; 43-Heating element; 44-Sealing cover; 45-Temperature control system; 451-Thermistor; 452-First resistor; 453-Second resistor; 454-Third resistor; 455-Electromagnetic relay; 456-Diode; 457-Transistor. Detailed Implementation

[0029] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Although some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the accompanying drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0030] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; and the term "optionally" means "optional embodiments". Definitions of other terms will be given in the following description. It should be noted that the concepts of "first," "second," etc., mentioned in this invention are used only to distinguish different devices, modules, or units, and are not intended to limit the order of functions performed by these devices, modules, or units or their interdependencies.

[0031] It should be noted that the terms "a" and "a plurality of" used in this invention are illustrative rather than restrictive. Those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0032] like Figures 1 to 3 As shown in the figure, an embodiment of the present invention provides a high-efficiency carbon dioxide gas decomposition device, which includes a first tube 1, a second tube 2, a metal electrode 3 and a carbon bed 4.

[0033] Both the first tube 1 and the second tube 2 are made of insulating material. The second tube 2 is sleeved on the first tube 1. There is a gap between the outer wall of the first tube 1 and the inner wall of the second tube 2. The second tube 2 is provided with a first air inlet 21 and a first air outlet 22 that communicate with the gap.

[0034] The metal electrode 3 is sleeved on the second tube 2, and the metal electrode 3 is used to connect to a high-voltage power supply and serve as a discharge positive electrode. The first tube 1 is used to house a circulating solution, and the solution in the first tube 1 serves as a grounding electrode and a cooling function.

[0035] Specifically, both the first tube 1 and the second tube 2 are straight tubes made of insulating material, such as glass tubes. The diameter of the second tube 2 is larger than that of the first tube 1. When the second tube 2 is fitted onto the first tube 1, there is a gap between the first tube 1 and the second tube 2. The end of the second tube 2 is sealed to the outer wall of the first tube 1, and the gap is used to allow carbon dioxide gas to pass through. The metal electrode 3 can be made of iron ring, copper ring, etc., and is fitted onto the outer wall of the second tube 2. The first tube 1 is a water pipe with an inlet and an outlet at each end. The inlet and outlet are used for the flow of solution (e.g., a sodium chloride solution of a certain concentration) to form a circulation within the first tube to ensure that the temperature remains low. The aqueous solution serves as a water electrode and is grounded. Thus, the aqueous solution, the first tube 1, the second tube 2, and the metal electrode 3 form a plasma discharge region.

[0036] In use, a low-temperature solution of a certain concentration is introduced into the first tube 1 and grounded. The metal electrode 3 is energized, and carbon dioxide is introduced into the gap between the first tube 1 and the second tube 2 through the first air inlet 21. The carbon dioxide gas reacts in this area to form a complex gas mixed with carbon dioxide, oxygen, carbon monoxide and oxygen ions.

[0037] The carbon bed 4 is disposed at the first gas outlet 22, and the carbon bed 4 is used to further decompose the complex gas output from the first gas outlet 22.

[0038] Specifically, after carbon dioxide undergoes one decomposition, a complex gas mixture of carbon monoxide, carbon dioxide, and oxygen is obtained. A carbon bed 4 is then used to further decompose this complex gas. The carbon bed 4 is connected to the first outlet 22. The complex gas discharged from the first outlet 11 undergoes further decomposition via a catalyst (e.g., activated carbon) within the carbon bed 4, resulting in a significant reduction in oxygen content and a substantial increase in carbon monoxide content. This produces a more concentrated mixture of carbon dioxide and carbon monoxide, reducing the complexity of the carbon dioxide decomposition process. The outlet of the carbon bed 4 can be connected to specialized equipment via a rubber hose, allowing the mixture after the two decompositions to be analyzed for its composition and content.

[0039] In this embodiment, both the first tube 1 and the second tube 2 are made of insulating material. The second tube 2 is fitted onto the first tube 1 with a gap between them. Carbon dioxide gas can be introduced through the first inlet on the second tube 2 and discharged through the first outlet. The metal electrode 3 is fitted onto the second tube 2 and is used to connect to a high-voltage power supply and serve as the positive electrode for discharge. A circulating solution is placed inside the first tube 1 as a grounding electrode. Thus, the aqueous solution, the first tube 1, the second tube 2, and the metal electrode 3 form a plasma discharge region. When the high-voltage power supply is turned on and carbon dioxide gas is introduced into the gap between the first tube 1 and the second tube 2 through the first inlet, the carbon dioxide gas undergoes initial decomposition, forming a complex gas mixed with carbon dioxide, oxygen, carbon monoxide, and oxygen ions, which is discharged through the first outlet. During the initial decomposition of carbon dioxide, the metal electrode 3 is externally placed, and the low-temperature solution circulating inside the first tube 1 continuously cools the gas, which can better control the temperature of the high-efficiency carbon dioxide gas decomposition device and thus improve the carbon dioxide conversion rate. The carbon bed 4 is connected to the first gas outlet 22. The complex gas obtained after gas decomposition enters the carbon bed 4 through the first gas outlet 22. The complex gas is further decomposed in the carbon bed 4 using a catalyst (such as activated carbon). A large amount of oxygen is consumed, and the carbon monoxide content increases, forming a mixed gas mainly composed of carbon dioxide and carbon monoxide. This effectively improves the conversion rate of carbon dioxide and reduces the complexity of the gas after conversion.

[0040] Optionally, the carbon bed 4 includes a reaction chamber 41, a hopper 42, and a heating element 43. The reaction chamber 41 is provided with a second air inlet 411 and a second air outlet 412. The second air inlet 411 is connected to the first air outlet 22, and the second air outlet 412 is used to connect to a detection device. The hopper 42 is connected to the reaction chamber 41 and is used to store activated carbon and transport the activated carbon to the reaction chamber 41. The heating element 43 is disposed inside the reaction chamber 41.

[0041] Specifically, such as Figure 2 and Figure 3 As shown, to ensure that the carbon bed 4 can provide sufficient reaction steps, reaction catalyst, and reaction temperature, a reaction chamber 41, a material silo 42, and a heating element 43 are provided. The second air inlet 411 of the reaction chamber 41 is connected to the first air outlet 22 and is used to introduce the complex gas after the initial decomposition of carbon dioxide. The material silo 42 is used to store the catalyst for the carbon reaction, such as activated carbon. The activated carbon can react rapidly with oxygen in the complex gas to convert oxygen into carbon monoxide. The heating element 43 heats the reaction chamber 41 to increase the temperature and increase the reaction rate. After a second reaction, a mixed gas containing carbon dioxide and carbon monoxide is discharged from the second air outlet 412 and can be connected to a detection device for testing.

[0042] Optionally, the hopper 42 has a funnel-shaped structure, with the small opening of the funnel-shaped structure communicating with the reaction chamber 41, and a sealing cover 44 detachably connected to the large opening.

[0043] Specifically, such as Figure 3 As shown, during the carbon reaction of complex gases in the carbon bed 4, the catalyst in the silo 42 is consumed. To facilitate timely replenishment of the catalyst, the silo 42 is designed as a funnel-shaped structure. The small opening of the funnel structure is connected to the reaction chamber 41. The catalyst stored in the silo 42 enters the reaction chamber below through the small opening of the funnel structure to replenish the catalyst lost in the reaction. A sealing cover 44 is detachably connected to the large opening of the funnel structure, allowing for the removal and replenishment of external catalyst through the opening and closing of the sealing cover 44. It should be noted that a sealing ring 421 is provided on the inner wall of the funnel structure near the large opening, which abuts against the sealing cover 44 to improve the sealing performance of the silo 42.

[0044] Optionally, such as Figure 2 As shown, multiple heating elements 43 are provided, and the multiple heating elements 43 are staggered in the reaction chamber 41. This can change the flow path of the complex gas, increase the reaction time of the complex gas in the reaction chamber 41, thereby improving the reaction efficiency of the complex gas, while also ensuring the temperature and temperature uniformity of the reaction chamber 41.

[0045] Optionally, the carbon bed 4 further includes a temperature control system 45, which is connected to the heating element 43 and is used to acquire and adjust the temperature of the heating element 43.

[0046] Specifically, such as Figure 3As shown, to ensure temperature stability in the reaction chamber 41 of the carbon bed 4, a temperature control system 45 is connected to the heating element 43 to detect the temperature in the reaction chamber 41 and adjust the temperature of the heating element 43 based on the acquired temperature. The temperature control system 45 includes an electromagnetic relay 455. The switching terminal of the electromagnetic relay 455 forms a circuit with the 220V power supply and the heating element 43. One end of the electromagnet of the electromagnetic relay 455 is connected to the power supply (12V power supply), and the other end is connected to the collector of a transistor 457. The emitter of the transistor 457 is grounded and connected in sequence to a first resistor 452 and a thermistor 451. The other end of the thermistor 451 is connected between the 12V power supply and the electromagnet, and the thermistor 451 (a PTC type) is placed in the reaction chamber 41. A second resistor 453 is disposed between the transistor 457, the first resistor 452, and... Between thermistors 451 and 452, during operation, thermistors 451 detect the temperature inside the reaction chamber 41. The resistance of thermistors 451 increases with rising temperature. The first resistor 452 and the second resistor 453 are ordinary resistors, enabling the temperature control system to operate normally. When the base voltage of transistor 457 is sufficiently high, a circuit is formed between the collector and emitter of the transistor. When the temperature inside the reaction chamber 41 is too low, the value of thermistor 451 decreases, the base voltage of transistor 457 increases, the emitter and collector of transistor 451 are connected, and the electromagnetic relay 455 closes, heating the heating element 43. It should be noted that the temperature inside the reaction chamber 41 can be changed by altering the resistance of the first resistor 452.

[0047] Furthermore, the temperature control system 45 also includes a third resistor 454 and a diode 456. The negative terminal of the diode 456 is connected between the electromagnet of the electromagnetic relay 455 and the power supply, and the negative terminal of the diode 456 is connected between the electromagnet of the electromagnetic relay 455 and the collector of the transistor 457. The two ends of the third resistor 454 are electrically connected to the base and emitter of the transistor 457 respectively, for the purpose of protecting the circuit.

[0048] Optionally, the first tube 1, the second tube 2, and the metal electrode 3 are coaxially arranged with each other.

[0049] In this embodiment, as Figure 1 and Figure 2 As shown, the first tube 1, the second tube 2, and the metal electrode 3 are arranged coaxially with each other, which can ensure the uniformity of the plasma discharge reaction in the decomposition of carbon dioxide.

[0050] Optionally, the two ends of the first tube 1 extend out to the two ends of the second tube 2.

[0051] Specifically, such as Figure 1As shown, the two ends of the first tube 1 extend to the two ends of the second tube 2 respectively, and the aqueous solution in the first tube can uniformly cool the plasma discharge reaction that takes place in the gap between the two.

[0052] Optionally, both the first tube 1 and the second tube 2 are quartz glass tubes.

[0053] Optionally, a catalyst is filled between the outer wall of the first tube 1 and the inner wall of the second tube 2.

[0054] Specifically, a catalyst is filled between the outer wall of the first tube 1 and the inner wall of the second tube 2. Under the action of the catalyst, carbon dioxide gas forms a complex gas that mixes carbon dioxide, oxygen, carbon monoxide and oxygen ions. Under the action of plasma, it forms a more complex chemical reaction, further improving the carbon dioxide conversion rate.

[0055] Optionally, the first air inlet 21 and the first air outlet 22 are respectively disposed at both ends of the second pipe body 2.

[0056] Specifically, such as Figure 2 As shown, the first air inlet 21 and the first air outlet 22 are respectively set at both ends of the second pipe body 2, so that after carbon dioxide enters the gap between the first pipe body 1 and the second pipe body 2 through the first air inlet 21, it has a certain flow distance in the gap, so that the carbon dioxide is fully decomposed and then flows out through the first air outlet 22, thereby increasing the decomposition efficiency of carbon dioxide.

[0057] In one embodiment of the present invention, the specific data of each structure are as follows:

[0058] The first tube 1 has a length of 180mm, a cross-sectional radius of 12mm, and a wall thickness of 1mm;

[0059] The second tube 2 has a length of 140mm, a cross-sectional radius of 20mm, and a wall thickness of 1mm.

[0060] When the second tube 2 is fitted onto the first tube 1, the second tube 2 is located in the center of the first tube 1. The outer surface of the first air inlet 21 is 10mm away from the left end of the first tube 1 and protrudes from the outer surface of the second tube 2. The first air inlet 21 is 20mm long and has a radius of 3mm. The outer surface of the first air outlet 22 is 50mm away from the right end of the first tube 1 and protrudes from the outer surface of the second tube 2. The first air outlet 22 is 20mm long and has a radius of 3mm.

[0061] The reaction chamber 41 of the carbon bed 4 is a hollow cylinder with a cross-sectional radius of 8 mm, a length of 10 mm, and a wall thickness of 1 mm.

[0062] The sealing cover 44 has a radius of 7mm and matches the large opening size of the hopper 42;

[0063] Thermistor 451 is a PTC 10kΩ, the first resistor 452 is a 20kΩ resistor, the second resistor 453 and the third resistor 454 are 5kΩ resistors, the transistor 457 is an NPN type SS8050 transistor, the maximum current of the electromagnetic relay 455 is about 1A, and the diode 456 is a common rectifier diode 1N4007.

[0064] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A high-efficiency carbon dioxide gas decomposition device, characterized in that, It includes a first tube (1), a second tube (2), a metal electrode (3), and a carbon bed (4); Both the first tube (1) and the second tube (2) are made of insulating material. The second tube (2) is sleeved on the first tube (1). There is a sealed gap between the outer wall of the first tube (1) and the inner wall of the second tube (2). The second tube (2) is provided with a first air inlet (21) and a first air outlet (22) that communicate with the gap. The metal electrode (3) is sleeved on the second tube (2), and the metal electrode (3) is used to connect to the high voltage power supply and serve as the positive electrode for discharge. The first tube (1) is used to set a circulating solution, and the solution in the first tube (1) serves as a grounding electrode and a cooling function. The carbon bed (4) is disposed at the first gas outlet (22), and the carbon bed (4) is used to convert the oxygen in the gas output from the first gas outlet (22) into carbon monoxide; The carbon bed (4) includes a reaction chamber (41), a hopper (42), and a heating element (43). The reaction chamber (41) is provided with a second air inlet (411) and a second air outlet (412). The second air inlet (411) is connected to the first air outlet (22). The second air outlet (412) is used to connect to a detection device. The hopper (42) is connected to the reaction chamber (41). The hopper (42) is used to store activated carbon and transport the activated carbon to the reaction chamber (41). The heating element (43) is disposed inside the reaction chamber (41). Multiple heating elements (43) are provided, and the multiple heating elements (43) are arranged alternately in the reaction chamber (41).

2. The high-efficiency carbon dioxide gas decomposition device according to claim 1, characterized in that, The hopper (42) has a funnel-shaped structure. The small opening of the funnel-shaped structure is connected to the reaction chamber (41), and a sealing cover (44) is detachably connected to the large opening of the funnel-shaped structure.

3. The high-efficiency carbon dioxide gas decomposition device according to claim 1, characterized in that, The carbon bed (4) also includes a temperature control system (45), which is connected to the heating element (43) and is used to acquire and adjust the temperature of the heating element (43).

4. The high-efficiency carbon dioxide gas decomposition device according to claim 1, characterized in that, The first tube (1), the second tube (2), and the metal electrode (3) are arranged coaxially with each other.

5. The high-efficiency carbon dioxide gas decomposition device according to claim 1, characterized in that, The two ends of the first tube (1) extend out to the two ends of the second tube (2).

6. The high-efficiency carbon dioxide gas decomposition device according to claim 1, characterized in that, Both the first tube (1) and the second tube (2) are quartz glass tubes.

7. The high-efficiency carbon dioxide gas decomposition device according to claim 1, characterized in that, A catalyst is filled between the outer wall of the first tube (1) and the inner wall of the second tube (2).

8. The high-efficiency carbon dioxide gas decomposition device according to claim 1, characterized in that, The first air inlet (21) and the first air outlet (22) are respectively located at both ends of the second tube (2).

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