Efficient desorption device based on less-water system

Abstract

The invention relates to the technical field of ship carbon emission reduction, in particular to an efficient desorption device based on a less-water system. According to the efficient desorption device based on the less-water system, a rich liquid main pipe is connected to the exterior of a tower body, a rich liquid diverter valve is arranged at the output end of the rich liquid main pipe, and a liquid outlet of the rich liquid diverter valve communicates with a rich liquid diverter mechanism and a tail gas heat exchange mechanism which are arranged in the tower body; an efficient desorption mechanism is connected above the tail gas heat exchange mechanism, and a demisting mechanism is arranged above the efficient desorption mechanism; a liquid outlet of the rich liquid distribution mechanism is located between the efficient desorption mechanism and the demisting mechanism, so that the desorption energy consumption of the ship carbon capture system is small, energy is fully utilized to improve the desorption efficiency of an absorbent, and the ship carbon capture system is simple and reasonable in structure, small in size and capable of effectively reducing the occupied space of a ship.

Description

Technical Field

[0001] The present invention relates to the technical field of ship carbon emission reduction, and particularly to an efficient desorption device based on a water-deficient system. Background Art

[0002] The greenhouse gas emissions of the shipping industry account for 3% of the global total emissions. In order to slow down the trend of global warming and achieve the goals of the Paris Climate Agreement, the International Maritime Organization (IMO) has issued guidelines on ship CO2 emission control, such as the Energy Efficiency Design Index (EEDI). IMO requires that by the end of 2050, the shipping industry should achieve a 50% carbon reduction based on 2008, which means that each ship should reduce about 85% of its CO 2 emissions. To address pollution prevention and CO 2 emission reduction issues, energy-saving measures and zero-carbon fuels are emerging continuously, such as desorption devices, but they consume a large amount of energy, resulting in poor speed and effectiveness of the carbon capture system deployed on ships. Because the current ship carbon capture system still uses traditional aqueous solution absorbents. Aqueous solution absorbents consume a large amount of energy during the desorption process, and it is difficult to achieve efficient desorption only relying on the energy provided by the ship engine exhaust gas. At the same time, in the existing ship carbon capture system, in order to effectively utilize the waste heat in the ship engine exhaust gas, a heat exchanger is used to heat the absorbent with the exhaust gas heat. However, in the existing system, the heat exchanger and the desorption tower are often arranged separately, resulting in excessive space occupation of the system. On the other hand, heating the rich absorbent solution with the waste heat of the ship engine exhaust gas will cause the CO 2 in the absorbent to desorb in advance, resulting in an increase in pipeline pressure, which in turn promotes the increase in the boiling point of the absorbent, making the rich solution a supersaturated liquid with gas under high pressure inside the pipeline. However, once the rich solution enters the desorption tower with a lower pressure, it will evaporate instantly, and the evaporated gas will flow out of the desorption tower from the top of the desorption tower without completing the conventional desorption process in the desorption tower, resulting in a significant reduction in the desorption effect.

[0003] In view of this, the present application aims to propose an efficient desorption device based on a water-deficient system to solve the problems of high desorption energy consumption, reduced desorption efficiency caused by the loss of absorbent from the top of the tower, and large space occupation of the device in the ship carbon capture system. Summary of the Invention

[0004] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art, and provide an efficient desorption device based on a water-deficient system.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows: An efficient desorption device based on a low-water system, including a tower body, a rich liquid main pipe is connected to the outside of the tower body, a rich liquid shunt valve is provided at the output end of the rich liquid main pipe, and the liquid outlet of the rich liquid shunt valve is communicated with a rich liquid shunt mechanism and a tail gas heat exchange mechanism arranged inside the tower body. An efficient desorption mechanism is connected above the tail gas heat exchange mechanism, and a demisting mechanism is provided above the efficient desorption mechanism; the liquid outlet of the rich liquid shunt mechanism is located between the efficient desorption mechanism and the demisting mechanism.

[0006] Further, the rich liquid shunt mechanism includes a rich liquid shunt pipe communicated with the rich liquid shunt valve, a spiral nozzle is installed at the output end of the rich liquid shunt pipe, and the spiral nozzle is arranged towards the efficient desorption mechanism.

[0007] Further, a pressure stabilizing valve for maintaining the pressure difference between the tail gas heat exchange mechanism and the efficient desorption mechanism is provided between the tail gas heat exchange mechanism and the efficient desorption mechanism.

[0008] Further, the tail gas heat exchange mechanism includes a rich liquid input pipe communicated with the rich liquid shunt valve, the output end of the rich liquid input pipe is connected with a rich liquid input cavity, a heat exchange cavity and a gas-liquid mixture output cavity are sequentially communicated above the rich liquid input cavity, and an absorbent heat exchange pipe and a tail gas baffle connected to the tower body are installed in the heat exchange cavity. The gas-liquid mixture output cavity is connected to the pressure stabilizing valve.

[0009] Further, an exhaust gas input pipe and an exhaust gas output pipe communicated with the heat exchange cavity are provided on the side of the tower body, and the exhaust gas input pipe is located above the exhaust gas output pipe.

[0010] Further, the efficient desorption mechanism includes a gas-liquid mixture conveying pipeline installed in the tower body and communicated with the pressure stabilizing valve. A mixture disturbance plate is provided in the gas-liquid mixture conveying pipeline, and an overflow weir is provided at the top of the gas-liquid mixture conveying pipeline.

[0011] Further, a filling cavity communicated with the overflow weir and a lean liquid buffer cavity communicated with the filling cavity are provided outside the gas-liquid mixture conveying pipeline. The filling cavity is filled with high-efficiency catalytic packing, and a lean liquid outflow pipe extending outside the tower body is communicated with the lean liquid buffer cavity.

[0012] Further, the high-efficiency catalytic packing is a perforated plate of a metal-based catalyst loaded with Ti ions, and the perforated plate is corrugated.

[0013] Further, the demisting mechanism includes a primary demister and a secondary demister, and the primary demister is arranged below the secondary demister.

[0014] Further, an air outlet is opened at the top of the tower body, and the air outlet is communicated with the secondary demister.

[0015] Compared with the prior art, the technical solution of the present application has the following beneficial effects:

[0016] 1. By combining a pressure stabilizing valve and an improved tower structure, the present application overcomes the problem that the absorbent escapes from the upper part of the desorption tower due to flash evaporation instantaneously when it enters the desorption tower, which occurs in the traditional land carbon capture desorption tower structure.

[0017] 2. The present application realizes controllable flash evaporation through a pressure stabilizing valve. In the tail gas heat exchange mechanism, the high heat brought by the tail gas will make the absorbent become supersaturated. The temperature and pressure of the absorbent in the heat exchanger are much higher than those in the desorption tower. By using the throttling effect of the pressure stabilizing valve, the absorbent can be instantaneously reduced to the set pressure after passing through the pressure stabilizing valve. At this time, due to the high temperature, the absorbent will instantaneously boil and evaporate from the liquid state into a gas-liquid mixture, thus realizing controllable flash evaporation.

[0018] 3. The present application uses a mixture disturbance plate to re-convert the particulate small liquid droplets in the mixture into liquid in the form of forced disturbance after flash evaporation. At this time, CO in the absorbent 2 affected by high temperature will not be re-absorbed by the absorbent, and only the effective components of the absorbent will be changed back into liquid by the disturbance, which can greatly improve the desorption efficiency of the absorbent.

[0019] 4. In the present application, the liquid in the gas-liquid mixture conveying pipeline continuously accumulates and flows out through the overflow weir, and falls into the high-efficiency catalytic packing for secondary desorption. Since there is almost no carbamate in the absorbent at this time, the catalyst can be used as an intermediate carrier to bypass the traditional reaction path of using bicarbonate for desorption, thereby further enhancing the desorption effect.

[0020] 5. Through the controllable flash evaporation of the pressure stabilizing valve, the forced condensation of the mixing disturbance plate, and the secondary desorption in the catalytic packing, the present application can realize that the cavity in the high-efficiency desorption device of the ship carbon capture system is different from the traditional desorption tower, which is only a one-way reaction of spraying the absorbent from the top and falling to the bottom of the tower, and can realize a two-way reaction under the same volume condition, effectively extending the reaction time.

[0021] 6. The device of the present application is only applicable to the water-deficient absorbent used in the present application. The water-deficient absorbent in the present application has the advantages of high boiling point and low specific heat. Under the condition of the same tail gas energy supply, 100% desorption efficiency can be achieved. At the same time, due to the higher boiling point, it is more likely to condense after being disturbed by flash evaporation. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic structural diagram of a high-efficiency desorption device based on a water-deficient system in a preferred embodiment of the present invention.

[0023] Reference numerals: 100, tower body;

[0024] 1. Rich liquid main pipe; 2. Rich liquid shunt valve; 3. Rich liquid shunt mechanism; 4. Tail gas heat exchange mechanism; 5. Pressure stabilizing valve; 6. High-efficiency desorption mechanism; 7. Rich liquid input pipe; 8. Rich liquid shunt pipe; 9. Spiral spray head; 10. Rich liquid input cavity; 11. Exhaust gas input pipe; 12. Exhaust gas output pipe; 13. Tail gas baffle; 14. Absorbent heat exchange pipe; 15. Gas-liquid mixture output cavity; 16. Gas-liquid mixture conveying pipeline; 17. Mixture disturbance plate; 18. Overflow weir; 19. High-efficiency catalytic packing; 20. Lean liquid buffer cavity; 21. Lean liquid outflow pipe; 22. Primary demister; 23. Secondary demister. Specific embodiments

[0025] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0026] Referring to Figure 1 As shown, a preferred embodiment of the present invention, a high-efficiency desorption device based on a low-water system, includes a tower body 100. The outside of the tower body 100 is connected to a rich liquid main pipe 1. The output end of the rich liquid main pipe 1 is provided with a rich liquid shunt valve 2. The liquid outlet of the rich liquid shunt valve 2 is communicated with a rich liquid shunt mechanism 3 and a tail gas heat exchange mechanism 4 arranged inside the tower body 100. Above the tail gas heat exchange mechanism 4 is connected a high-efficiency desorption mechanism 6. Above the high-efficiency desorption mechanism 6 is provided a demisting mechanism; the liquid outlet of the rich liquid shunt mechanism 6 is located between the high-efficiency desorption mechanism 6 and the demisting mechanism, so that the desorption energy consumption of the ship carbon capture system is small, and the energy is fully utilized to improve the desorption efficiency of the absorbent. The structure of this application is simple, reasonable, and small in volume, and can effectively reduce the space occupied by the ship.

[0027] As a preferred embodiment of the present invention, it may also have the following additional technical features: The rich liquid shunt mechanism 3 includes a rich liquid shunt pipe 8 communicated with the rich liquid shunt valve 2. The output end of the rich liquid shunt pipe 8 is installed with a spiral spray head 9, and the spiral spray head 9 is arranged towards the high-efficiency desorption mechanism 6. This spiral spray head 9 is used to spray the rich liquid. By the way of rich liquid shunt, less absorbent can enter the tail gas heat exchange mechanism 4. Under the condition of constant heat, the less the absorbent, the higher the temperature that can be reached. At the same time, the shunted absorbent can also be sprayed from the top of the desorption tower to cool the desorbed gas, reduce the volatilization of components in the absorbent, and recover the heat in the desorbed gas.

[0028] In this embodiment, a pressure regulating valve 5 is provided between the tail gas heat exchange mechanism 4 and the high-efficiency desorption mechanism 6 to maintain the pressure difference between the tail gas heat exchange mechanism 4 and the high-efficiency desorption mechanism 6. Therefore, due to the heating effect of the tail gas in the tail gas heat exchange mechanism 4, the absorbent will be heated to become a high-temperature and high-pressure supersaturated liquid, and after passing through the pressure regulating valve 5, the pressure will be instantly reduced due to the interception effect, and the absorbent at this time will instantly evaporate the CO generated by the reaction in the absorbent. 2 Release it, greatly improving the desorption effect.

[0029] In this embodiment, the exhaust gas heat exchange mechanism 4 includes a rich liquid input pipe 7 connected to the rich liquid diverter valve 2, the output end of the rich liquid input pipe 7 is connected to a rich liquid input chamber 10, the upper part of the rich liquid input chamber 10 is connected to a heat exchange chamber and a gas-liquid mixture output chamber 15 in sequence, the heat exchange chamber is installed with an absorbent heat exchange pipe 14 connected to the tower body and an exhaust baffle 13, the gas-liquid mixture output chamber 15 is connected to the pressure regulating valve 5; and the side of the tower body 100 is provided with an exhaust gas input pipe 11 and an exhaust gas output pipe 12 connected to the heat exchange chamber, the exhaust gas input pipe 11 is located above the exhaust gas output pipe 12. Among them, the exhaust gas heat exchange mechanism 4 is mainly used to utilize the waste heat of the exhaust gas from the engine, heat the rich liquid by the heat of the engine exhaust gas, and make the CO in the rich liquid 3 2- / HCO 3 - The first step reaction releases CO 2 .

[0030] In this embodiment, the high-efficiency desorption mechanism 6 includes a gas-liquid mixture delivery pipeline 16 installed in the tower body 100 and connected to the pressure-stabilizing valve 5, a mixture disturbance plate 17 is provided in the gas-liquid mixture delivery pipeline 16, an overflow weir 18 is provided at the top of the gas-liquid mixture delivery pipeline 16, a filling chamber 19 connected to the overflow weir 18 and a lean liquid buffer chamber 20 connected to the filling chamber 19 are provided outside the gas-liquid mixture delivery pipeline 16, the filling chamber 19 is filled with high-efficiency catalytic filler, and the lean liquid buffer chamber 20 is connected to a lean liquid outflow pipe 21 extending from the outside of the tower body 100. The high-efficiency desorption mechanism 6 enhances the desorption effect by enhancing the separation of the gas-liquid mixture, allowing the gas to flow out from the top of the tower, and the liquid undergoes secondary desorption during the falling process.

[0031] The mixture disturbance plate 17 is used to utilize the forced blocking effect in the gas-liquid mixture delivery pipeline 16 to force condensation of the evaporated mixture flowing out from the rear of the pressure regulating valve 5. At this time, due to the high temperature of the mixture, the CO 2 The condensation products will not be reabsorbed again, and the condensation products will continue to accumulate in the pipeline and flow out from the overflow weir 18.

[0032] In this embodiment, the high-efficiency catalytic packing is a perforated plate of a metal-based catalyst loaded with Ti ions, and the perforated plate is corrugated. This high-efficiency catalytic packing can catalyze the carbamate in the absorbent and extend the reaction area and residence time of the absorbent through a dense void structure.

[0033] In this embodiment, the demisting mechanism includes a primary demister 22 and a secondary demister 23. The primary demister 22 is arranged below the secondary demister 23, and an air outlet is opened at the top of the tower body 100. The air outlet is communicated with the secondary demister 23. After the mixed gas is cooled by the rich liquid of the absorbent, it continues to flow upward, passes through the primary demister 22 for primary demisting, and condenses the residual absorbent in the mixed gas again. Finally, the mixed gas passes through the secondary demister to deeply condense the residual absorbent in the mixed gas. Finally, it is discharged from the top of the desorption tower and enters the subsequent process.

[0034] The absorbent used in a high-efficiency desorption device based on a low-water system in this application is a low-water absorbent with a polyamine structure, which is composed of a chain amine molecule with a primary amine group at the end side of the molecule and a tertiary amine group in the molecule, an organic solvent with a low specific heat capacity, and water. The proportion is that the mass concentration of the polyamine molecule is 20%-30%, the mass concentration of the organic solvent is 40%-60%, and the mass concentration of water is 10%-40%

[0035] During use, the rich liquid of the absorbent enters the high-efficiency desorption device from the main rich liquid pipe 1 and is divided into two fluid streams at the rich liquid shunt valve 2. Among them, a small amount of absorbent enters the desorption tower from above the desorption tower through the rich liquid shunt mechanism 3, and another part of the larger amount of absorbent enters the desorption tower from the bottom of the desorption tower through the rich liquid input pipe 7.

[0036] The fluid with a larger flow rate enters the tail gas heat exchange mechanism 4 at the bottom of the desorption tower through the rich liquid input pipe 7. The tail gas heat exchange mechanism 4 mainly uses the waste heat in the ship engine tail gas to heat the absorbent through a shell-and-tube structure, so that the CO 2 released again in a chemical reaction manner. Limited by the reaction time, most of the CO released in the tail gas heat exchange mechanism 4 2 comes from the HCO contained in the rich liquid 3 - / CO 3 2- , and a small part of the CO decomposed from the carbamate 2. In the tail gas heat exchange mechanism 4, the rich absorbent input pipe 7 enters the rich liquid input chamber 10 at the bottom of the desorption tower, slowly accumulates and rises in the rich liquid input chamber 10, and then enters the absorbent heat exchange pipe 14. In the absorbent heat exchange pipe 14, the absorbent is heated by heat exchange from the outside of the pipe by the waste gas entering from the waste gas input pipe 11, and thus becomes a supersaturated liquid with gas at high temperature and high pressure. With the continuous supply of absorbent at the bottom of the tower, the gas-liquid mixture in the absorbent heat exchange pipe 14 will continuously rise, enter the gas-liquid mixture output chamber 15, and finally reach the pressure stabilizing valve 5. After the heat exchange, the waste gas will be discharged from the waste gas output pipe.

[0037] At the pressure stabilizing valve 5, the gas-liquid mixture remains in a high temperature and high pressure state. Through the throttling action of the pressure stabilizing valve 5, the pressure of the gas-liquid mixture drops instantaneously. Under low pressure, the boiling point of the liquid will decrease. At this time, since the gas-liquid mixture still maintains a high energy state, most of the liquid in the gas-liquid mixture will flash into steam. In the original gas-liquid mixture, the gas composition is mainly CO released by the desorption of the absorbent 2 , and the liquid composition is mainly the rich absorbent and dissolved CO 2 . Through the flashing process, the CO dissolved in the liquid phase 2 will also be released, realizing the separation of CO 2 from the liquid phase, which can effectively improve the desorption efficiency.

[0038] The gas-liquid mixture leaving the pressure stabilizing valve 5 will enter the gas-liquid mixture conveying pipeline 16, and a mixture disturbing plate 17 is arranged in the gas-liquid mixture conveying pipeline 16. Under the forced disturbance of the mixture disturbing plate 17, the fine steam droplets in the gas-liquid mixture are transformed into larger droplets, which adhere to the surface of the mixture disturbing plate 17 and gradually accumulate into a flow stream, while the gas bypasses the disturbing plate and continues to rise, finally realizing gas-liquid separation in the gas-liquid mixture conveying pipeline 16.

[0039] The accumulated flow stream is continuously conveyed upward, falls through the overflow weir 18 into the high-efficiency catalytic packing outside the gas-liquid mixture conveying pipeline 16. In the high-efficiency catalytic packing, the absorbent falling from above wets the surface of the packing, forms a liquid film on the surface of the packing, and a catalytic reaction occurs under the action of the catalyst loaded on the packing to further release CO 2 . At this time, the main source of CO 2 is the unreacted carbamate in the absorbent. Since the high-efficiency catalytic packing has dense pores inside, it can effectively extend the residence time of the absorbent, and under the catalysis of the catalyst, CO 2 can be further released, finally realizing the ultra-high efficiency desorption of the absorbent. The absorbent that has completed all desorption tasks will accumulate in the lean liquid buffer chamber 20 below the high-efficiency desorption mechanism 6, and finally flow out from the lean liquid outflow pipe 21.

[0040] The gas released in the high-efficiency desorption mechanism 6 is mainly CO 2 , but there may still be some uncondensed absorbent. The mixed gas will flow upward above the high-efficiency desorption mechanism 6 and be cooled by the rich absorbent liquid sprayed from the spiral nozzle 9 during the flow. At this time, the temperature of the mixed gas is relatively high, while the temperature of the rich absorbent liquid is relatively low. The rich absorbent liquid will play a certain cooling role on the mixed gas, and the rich absorbent liquid will condense and carry away part of the uncondensed absorbent in the gas. And because the CO 2 loading of the rich absorbent liquid is large, there will be no situation of CO 2 re-absorption, and due to the heat exchange effect, the temperature of the rich absorbent liquid further rises, and it can meet the minimum temperature requirement for catalytic desorption after falling onto the high-efficiency catalytic packing 19. The mixed gas continues to flow upward after being cooled by the rich absorbent liquid, passes through the primary demister 22 for primary demisting, and condenses the residual absorbent in the mixed gas again. Finally, the mixed gas will pass through the secondary demister to deeply condense the residual absorbent in the mixed gas. Finally, it is discharged from the top of the desorption tower and enters the subsequent process.

[0041] On the premise of no conflict, those skilled in the art can freely combine and superimpose the above-mentioned additional technical features.

[0042] It can be understood that the present invention is described through some embodiments. Those skilled in the art know that without departing from the spirit and scope of the present invention, various changes or equivalent replacements can be made to these features and embodiments. In addition, under the teaching of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application belong to the scope protected by the present invention.

Claims

1. An efficient desorption device based on a low-water system, characterized in that: It comprises a tower body, the outside of which is connected to a rich liquid main pipe, the output end of which is provided with a rich liquid diverter valve, the liquid outlet of the rich liquid diverter valve is connected to a rich liquid diverter mechanism and an exhaust gas heat exchange mechanism arranged inside the tower body, a high-efficiency desorption mechanism is connected above the exhaust gas heat exchange mechanism, a defogger mechanism is provided above the high-efficiency desorption mechanism; the liquid outlet of the rich liquid diverter mechanism is located between the high-efficiency desorption mechanism and the defogger mechanism.

2. The high-efficiency desorption device based on a low-water system according to claim 1, characterized in that: The rich liquid diversion mechanism comprises a rich liquid diversion pipe connected to the rich liquid diversion valve, and a spiral nozzle is installed at the output end of the rich liquid diversion pipe, and the spiral nozzle is arranged toward the high-efficiency desorption mechanism.

3. The high-efficiency desorption device based on a low-water system according to claim 1, characterized in that: A pressure stabilizing valve for maintaining the pressure difference between the exhaust gas heat exchange mechanism and the high-efficiency desorption mechanism is provided between the exhaust gas heat exchange mechanism and the high-efficiency desorption mechanism.

4. The high-efficiency desorption device based on a low-water system according to claim 3 is characterized in that: The exhaust gas heat exchange mechanism includes a rich liquid input pipe connected to the rich liquid diverter valve, the output end of the rich liquid input pipe is connected to a rich liquid input chamber, the top of the rich liquid input chamber is connected to a heat exchange chamber and a gas-liquid mixture output chamber in sequence, and the heat exchange chamber is installed with an absorbent heat exchange tube connected to the tower body and an exhaust gas baffle; the gas-liquid mixture output chamber is connected to the pressure stabilizing valve.

5. The high-efficiency desorption device based on a low-water system according to claim 4, characterized in that: The side of the tower body is provided with an exhaust gas input pipe and an exhaust gas output pipe which are connected with the heat exchange cavity, and the exhaust gas input pipe is located above the exhaust gas output pipe.

6. The high-efficiency desorption device based on a low-water system according to claim 3, characterized in that: The high-efficiency desorption mechanism comprises a gas-liquid mixture delivery pipeline installed in the tower body and connected to the pressure-stabilizing valve, a mixture disturbance plate is arranged in the gas-liquid mixture delivery pipeline, and an overflow weir is arranged on the top of the gas-liquid mixture delivery pipeline.

7. The high-efficiency desorption device based on a low-water system according to claim 6, characterized in that: A filling chamber connected to the overflow weir and a lean liquid buffer chamber connected to the filling chamber are provided outside the gas-liquid mixture delivery pipeline. The filling chamber is filled with high-efficiency catalytic filler, and the lean liquid buffer chamber is connected to a lean liquid outflow pipe extending outside the tower body.

8. The high-efficiency desorption device based on a low-water system according to claim 7, characterized in that: The high-efficiency catalytic filler is a perforated plate of a metal-based catalyst loaded with Ti ions, and the perforated plate is corrugated.

9. The high-efficiency desorption device based on a low-water system according to claim 1, characterized in that: The defogger mechanism comprises a primary defogger and a secondary defogger, and the primary defogger is arranged below the secondary defogger.

10. The high-efficiency desorption device based on a low-water system according to claim 9, characterized in that: An air outlet is provided at the top of the tower body, and the air outlet is communicated with the secondary demister.

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