Pre-swirl device and flue gas cleaning system and method

Abstract

The application discloses a pre-rotation cyclone device, a flue gas purification system and a purification method. The system comprises three pre-rotation cyclone devices for water washing dust removal, pollutant absorption and absorbent regeneration. The pre-rotation cyclone device comprises an outer cylinder, a plurality of pre-rotation cyclones and upper, middle and lower layer partitions. The outer cylinder is provided with a gas outlet and a liquid outlet. The cylinder wall between the upper and middle layer partitions is provided with a first radial inlet, and the cylinder wall between the middle and lower layer partitions is provided with a second radial inlet. The pre-rotation unit of the pre-rotation cyclone comprises a cylindrical absorption cavity and a first tangential feed channel located between the upper and middle layer partitions. The cylindrical absorption cavity is arranged on the middle and lower layer partitions, and the cavity wall between the middle and lower layer partitions is provided with a liquid inlet hole. The fluid mixing unit comprises a cylindrical mixing cavity. The cyclone separation unit comprises an upper layer cylindrical separation cavity, an overflow pipe and an underflow pipe. The cylindrical mixing cavity is tangentially connected with the upper layer cylindrical separation cavity. The overflow pipe outlet is located above the upper layer partition, and the underflow pipe outlet is located below the lower layer partition.

Description

Technical Field

[0001] This invention belongs to the field of waste gas treatment technology, specifically, it relates to a pre-rotating cyclone device, a flue gas purification system, and a purification method. Background Technology

[0002] With the advancement of modern industry, while bringing greater convenience to life, air pollution caused by fuels used in transportation and industrial production has become increasingly serious. Pollutants such as CO2, H2S, NOx, SO2, and VOCs in exhaust gases enter the atmosphere, causing severe damage to atmospheric structure and leading to various climate problems. In recent years, people's environmental awareness has gradually increased, and air pollution has attracted worldwide attention and widespread societal concern, resulting in a surge of research on exhaust gas treatment. Among these efforts, the most significant focus is on controlling carbon emissions from the exhaust of automobiles, airplanes, and ships, as well as from the combustion of fossil fuels such as coal, oil, and natural gas.

[0003] Currently, there are three main methods for capturing carbon from waste gas: pre-combustion treatment, post-combustion treatment, and pure oxygen combustion. In the current chemical and energy industry, the most widely used method is post-combustion treatment, which involves cooling, dust removal, desulfurization, and denitrification of the flue gas before sending it to CO2 capture equipment to complete the capture and separation of CO2.

[0004] Common methods for CO2 separation and capture include membrane separation, cryogenic separation (low-temperature distillation), adsorbent adsorption, physical absorption, and chemical solvent absorption. Membrane separation requires relatively simple materials, but for flue gas with complex compositions, the separation process is easily affected by other gas components in the waste gas besides the target analyte, and the separation efficiency is low. Cryogenic separation is mainly suitable for the absorption and capture of high-concentration CO2, but it has the disadvantage of a long process route. Adsorbent adsorption achieves capture by contacting CO2 with the adsorbent, but once the adsorbent and CO2 are adsorbed and bound, they are difficult to separate, which is not conducive to regeneration. Physical absorption generally uses high pressure and low temperature for absorption and desorption uses reduced pressure or increased temperature. It uses a small amount of absorbent and does not require heating for regeneration, but this method is only suitable for conditions with high CO2 partial pressure, and the degree of CO2 removal is not high. Chemical solvent absorption is currently the most widely used flue gas CO2 capture process in industry. This method removes CO2 from the mixed gas by fully contacting natural gas containing CO2 with a chemical absorbent. The CO2-rich absorbent solution can be regenerated by heating to remove CO2 and obtain a lean solution for recycling.

[0005] In industrial applications of chemical solvent absorption, cooled mixed flue gas is typically fed into an absorption tower. The amine-rich solution, after absorbing CO2, recovers heat through a lean-rich solution heat exchanger and is then sent to a regeneration tower for high-temperature regeneration, producing a lean amine solution. The high-concentration CO2 that is removed is then condensed and separated to remove water vapor before proceeding to subsequent treatment stages. However, traditional tower structures require a large floor space, have short gas-liquid contact times, and low absorption reaction efficiency, failing to achieve the desired flue gas purification effect. Summary of the Invention

[0006] The present invention was made to solve the above-mentioned problems, and its purpose is to provide a pre-rotating cyclone device, a flue gas purification system, and a purification method.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A pre-rotating cyclone device includes an outer cylinder, a plurality of pre-rotating cyclones located inside the outer cylinder and connected in parallel, and an upper baffle, a middle baffle, and a lower baffle arranged from top to bottom inside the outer cylinder, wherein:

[0009] The outer cylinder has a gas outlet at the top and a liquid outlet at the bottom. A first radial inlet is provided on the cylinder wall between the upper and middle partitions, and a second radial inlet is provided on the cylinder wall between the middle and lower partitions.

[0010] The pre-rotating cyclone separator includes a pre-rotating unit, a fluid mixing unit, and a cyclone separation unit connected in sequence. The pre-rotating unit includes a vertically arranged cylindrical absorption chamber, a mandrel arranged along the center line of the cylindrical absorption chamber, and a first tangential feed channel connected to the upper part of the cylindrical absorption chamber. The first tangential feed channel is located between the upper partition and the middle partition. The cylindrical absorption chamber passes through the middle partition and the lower partition, and several liquid inlet holes are opened on the cavity wall between the middle partition and the lower partition. The fluid mixing unit includes a cylindrical mixing chamber arranged horizontally below the lower partition and several guide vanes arranged in the cylindrical mixing chamber. The cyclone separation unit includes an upper cylindrical separation chamber, a lower conical separation chamber, a top overflow pipe, and a bottom underflow pipe arranged coaxially. The outlet of the cylindrical mixing chamber is tangentially connected to the upper cylindrical separation chamber. The outlet of the overflow pipe is located above the upper partition, and the outlet of the underflow pipe is located below the lower partition.

[0011] Furthermore, the fluid mixing unit also includes a fixed rod disposed on the center line of the cylindrical mixing cavity, two guide vanes as a group, several groups of guide vanes arranged along the length of the fixed rod, two guide vanes in the same group disposed opposite to each other on both sides of the fixed rod and inclined in opposite directions, intersecting and staggering each other.

[0012] A flue gas purification system includes three pre-rotating cyclone devices as described above. Each pre-rotating cyclone device is a water washing dust removal device, a pollutant absorption device, and an absorbent regeneration device, wherein:

[0013] The first radial inlet of the water washing dust removal device is used to introduce the flue gas to be treated, and the second radial inlet is used to introduce the washing water.

[0014] The first radial inlet of the pollutant absorption device is connected to the gas outlet of the water washing dust removal device, and the liquid outlet of the pollutant absorption device is connected to the first radial inlet of the absorbent regeneration device.

[0015] The liquid outlet of the absorbent regeneration device is connected to the second radial inlet of the pollutant absorption device;

[0016] The flue gas purification system also includes a reboiler, and the bottom of the absorbent regeneration device is provided with a bypass liquid outlet, which is connected to the reboiler inlet, and the reboiler outlet is connected to the second radial inlet of the absorbent regeneration device.

[0017] Heat exchangers are installed in two passages: between the liquid outlet of the pollutant absorption device and the first radial inlet of the absorbent regeneration device, and between the liquid outlet of the absorbent regeneration device and the second radial inlet of the pollutant absorption device. A microchannel separator is also provided outside the second radial inlet of the pollutant absorption device.

[0018] Furthermore, the flue gas purification system also includes a water tank connected to the liquid outlet and second radial inlet of the water washing dust removal device, and the outlet of the water tank is equipped with a liquid pump.

[0019] Preferably, the heat exchanger is a plate heat exchanger, and a liquid pump is installed on each of the two passages through the heat exchanger.

[0020] Preferably, the microchannel separator is a cross-flow nanofiltration microchannel separator, and the equivalent diameter of the particulate filter media used in the microchannel separator is 0.21 mm to 0.4 mm.

[0021] Furthermore, the flue gas purification system also includes a micro cyclone separator connected to the gas outlet of the absorbent regeneration device and the inlet of the reboiler, which is used to separate a small amount of absorbent liquid entrained in the gaseous pollutants.

[0022] Furthermore, the flue gas purification system also includes a dosing tank connected to the second radial inlet of the absorbent regeneration device, and a liquid pump is installed in the passage between the dosing tank and the absorbent regeneration device.

[0023] A flue gas purification method, using the above-mentioned flue gas purification system, includes:

[0024] Water washing dust removal process: The flue gas to be treated and the washing water are passed into the water washing dust removal device to shake and wash the particulate matter in the flue gas. The washing water and particulate matter are discharged into the water pool and the flue gas flows to the pollutant absorption device.

[0025] Pollutant absorption stage: The absorbent filtered by the microchannel separator is introduced into the pollutant absorption device, where it comes into contact with and reacts with the pollutants in the flue gas. The purified gas after removing the pollutants is discharged, and the rich liquid of the absorbent that has absorbed the pollutants flows to the absorbent regeneration device after being heated by the heat exchanger.

[0026] Absorbent regeneration stage: At the same time as the rich absorbent solution enters the absorbent regeneration device, the lean absorbent solution heated by the reboiler is also introduced into the absorbent regeneration device to mix with it. The rich absorbent solution and the lean absorbent solution react at high temperature to regenerate the rich solution into a lean solution. Part of the regenerated lean absorbent solution flows to the reboiler for heating, while the other part of the lean absorbent solution exchanges heat with the rich solution in the heat exchanger to cool down before returning to the pollutant absorption device.

[0027] Furthermore, the flue gas purification system also includes a micro cyclone separator connected to the gas outlet of the absorbent regeneration device and the inlet of the reboiler;

[0028] The flue gas purification method also includes a gas drying step: the high-concentration pollutant gas released during absorbent regeneration enters a micro-cyclone separator, which separates a small amount of absorbent entrained in the pollutant gas to obtain dry pollutant gas. The separated absorbent flows into a reboiler for heating.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. In the pre-rotating cyclone device of the present invention, the fluid sequentially passes through the pre-rotating unit, the fluid mixing unit, and the cyclone separation unit of the pre-rotating cyclone, resulting in a long flow path and more sufficient contact and reaction time between substances. Through the breaking up of the liquid by the rotating turbulence in the pre-rotating unit and the guiding of the fluid by the blades in the fluid mixing unit, the specific surface area of ​​the fluid can be effectively increased, making the contact between the two fluids entering the pre-rotating cyclone more sufficient and the mixing more uniform. Since the pre-rotating unit provides the droplets with initial rotation speed and revolution speed, it can enhance the internal self-circulation of the droplets, accelerate the liquid film renewal rate, and improve the mass transfer efficiency.

[0031] 2. In the pre-rotating cyclone device of the present invention, multiple pre-rotating cyclones are installed in parallel in the same outer cylinder, which can greatly improve the waste gas treatment capacity and treatment efficiency.

[0032] 3. In the flue gas purification system and purification method of the present invention, a pre-rotating cyclone device is used in the water washing dust removal, pollutant absorption and absorbent regeneration stages, which can reduce operating costs. The structure of the pre-rotating cyclone device can achieve high efficiency in dust removal and desorption, and the equipment occupies a small area. The loss of amine liquid in the system is small, the gas-liquid contact time is long, the absorption reaction efficiency is high, and a more ideal flue gas purification effect can be achieved. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the pre-rotating cyclone device;

[0034] Figure 2 This is a schematic diagram of the structure of a pre-rotating cyclone.

[0035] Figure 3 This is a cross-sectional view of the fluid mixing unit;

[0036] Figure 4 This is a fluid flow diagram of a flue gas purification system;

[0037] Figure 5 This is a flowchart of a flue gas purification method.

[0038] Icon labels:

[0039] 100-Pre-rotating cyclone device, 100a-Water washing dust removal device, 100b-Pollutant absorption device, 100c-Absorbent regeneration device;

[0040] 10-Outer cylinder, 11-Gas outlet, 12-Liquid outlet, 13-First radial inlet, 14-Second radial inlet, 15-First outer chamber, 16-Second outer chamber, 17-Third outer chamber, 18-Fourth outer chamber, 19-Bypass liquid outlet;

[0041] 20-Pre-rotating hydrocyclone, 21-Pre-rotating unit, 211-Cylindrical absorption chamber, 2111-Liquid inlet, 212-Core rod, 213-First tangential feed channel, 22-Fluid mixing unit, 221-Cylindrical mixing chamber, 222-Guide vane, 223-Fixed rod, 23-Swirl separation unit, 231-Upper cylindrical separation chamber, 232-Lower conical separation chamber, 233-Overflow pipe, 234-Underflow pipe;

[0042] 31-Upper partition, 32-Middle partition, 33-Lower partition;

[0043] 201-Reboiler, 202-Heat exchanger, 203-Microchannel separator, 204-Water tank, 205-Liquid pump, 206-Micro cyclone separator, 207-Water cooler, 208-Air pump, 209-Dosing tank. Detailed Implementation

[0044] To make the technical means, creative features, objectives and effects of the present invention easy to understand, the following embodiments, in conjunction with the accompanying drawings, specifically illustrate the pre-rotating cyclone device, flue gas purification system and purification method of the present invention.

[0045] Example 1

[0046] like Figures 1-3As shown, this embodiment provides a pre-rotating cyclone device 100, including: an outer cylinder 10, a plurality of pre-rotating cyclones 20 located inside the outer cylinder 10 and connected in parallel, and an upper baffle 31, a middle baffle 32, and a lower baffle 33 arranged from top to bottom inside the outer cylinder 10, wherein:

[0047] The outer cylinder 10 has a gas outlet 11 at the top and a liquid outlet 12 at the bottom. A first radial inlet 13 is provided on the cylinder wall between the upper partition 31 and the middle partition 32, and a second radial inlet 14 is provided on the cylinder wall between the middle partition 32 and the lower partition 33.

[0048] The pre-rotating cyclone separator 20 includes a pre-rotating unit 21, a fluid mixing unit 22, and a cyclone separation unit 23 connected in sequence. The pre-rotating unit 21 includes a vertically arranged cylindrical absorption chamber 211, a core rod 212 arranged along the centerline of the cylindrical absorption chamber 211, and a first tangential feed channel 213 connected to the upper part of the cylindrical absorption chamber 211. The first tangential feed channel 213 is located between the upper partition 31 and the middle partition 32. The cylindrical absorption chamber 211 passes through the middle partition 32 and the lower partition 33. Several liquid inlet holes 2111 are formed on the cavity wall of the cylindrical absorption chamber 211 located between the middle partition 32 and the lower partition 33. The fluid mixing unit 22 includes a cylindrical mixing chamber 221 arranged laterally below the lower partition 33 and several guide vanes 222 disposed within the cylindrical mixing chamber 221. The cyclone separation unit 23 includes an upper cylindrical separation chamber 231, a lower conical separation chamber 232, a top overflow pipe 233, and a bottom underflow pipe 234, all coaxially arranged. The outlet of the cylindrical mixing chamber 221 is tangentially connected to the upper cylindrical separation chamber 231. The outlet of the overflow pipe 233 is located above the upper partition 31, and the outlet of the underflow pipe 234 is located below the lower partition 33.

[0049] Specifically, the upper partition 31, the middle partition 32 and the lower partition 33 are arranged at intervals, and the edges of the partitions are sealed to the inner wall of the outer cylinder 10, thereby dividing the interior of the outer cylinder 10 into four independent spaces, which are referred to as the first outer chamber 15, the second outer chamber 16, the third outer chamber 17 and the fourth outer chamber 18 from top to bottom for ease of description. Overflow pipe 233 is installed on upper partition 31, middle partition 32 and lower partition 33. The outlet of overflow pipe 233 is located in the first outer chamber 15. Gas outlet 11 is connected to the first outer chamber 15 so that gas can flow out of outer cylinder 10. First radial inlet 13 is connected to the second outer chamber 16 so as to introduce gas, liquid or gas-liquid mixture into outer cylinder 10. Second radial inlet 14 is connected to the third outer chamber 17 so as to introduce liquid into outer cylinder 10. The outlet of underflow pipe 234 is located in the fourth outer chamber 18 so as to introduce liquid out of outer cylinder 10. Liquid outlet 12 is connected to the fourth outer chamber 18 so as to allow liquid to flow out of outer cylinder 10.

[0050] Furthermore, the fluid mixing unit 22 also includes a fixed rod 223 disposed on the center line of the cylindrical mixing chamber 221, with two guide vanes 222 forming a group, and several groups of guide vanes 222 arranged along the length of the fixed rod 223. Two guide vanes 222 in the same group are disposed opposite each other on both sides of the fixed rod 223, inclined in opposite directions, and staggered. Preferably, all guide vanes 222 are at a 45° angle to the horizontal plane, and two guide vanes 222 in the same group are perpendicular to each other. After the fluid enters the fluid mixing unit 22, due to the guiding effect of the guide vanes 222, the fluids on both sides will cross-movement when passing through two guide vanes 222 in the same group, allowing fluids A and B to be further and fully mixed, while also prolonging the contact and reaction time between them.

[0051] Appendix Figure 1 In order to clearly illustrate the internal structure of the pre-rotating cyclone device 100, only two pre-rotating cyclones 20 are shown inside the cylinder 10. In practical applications, the pre-rotating cyclone device 100 can be equipped with thousands or tens of thousands of pre-rotating cyclones 20, which are installed in parallel in the same outer cylinder 10, which can significantly improve the waste gas treatment capacity and treatment efficiency.

[0052] When the pre-rotating cyclone device 100 is working, fluid A (gas, liquid, or gas-liquid mixture) enters the second outer chamber 16 through the first radial inlet 13 and flows into each pre-rotating cyclone 20 through the first tangential feed channel 213. Fluid B (liquid) enters the third outer chamber 17 through the second radial inlet 14, forms a jet through the liquid inlet hole 2111 on the cylindrical absorption chamber 211, enters the cylindrical absorption chamber 211 and contacts fluid A, then flows into the fluid mixing unit 22 for further thorough mixing, and finally enters the cyclone separation unit 23 for gas-liquid separation. The gas separated by each pre-rotating hydrocyclone 20 flows out from the overflow pipe 233 and merges into the first outer chamber 15, and finally flows out of the pre-rotating hydrocyclone device 100 from the gas outlet 11 at the top of the outer cylinder 10; while the liquid separated by each pre-rotating hydrocyclone 20 flows out from the bottom flow pipe 234 and merges into the fourth outer chamber 18, and finally flows out of the pre-rotating hydrocyclone device 100 from the liquid outlet 12 at the bottom of the outer cylinder 10.

[0053] During this process, fluid A enters the pre-rotation unit 21 through the first tangential feed channel 213 and forms a rotating turbulent flow in the cylindrical absorption cavity 211. Fluid B enters the cylindrical absorption cavity 211 in the form of a jet. Due to the radial velocity gradient of the three-dimensional rotating turbulent flow of fluid A in the cylindrical absorption cavity 211, the continuous fluid B is tangentially broken and atomized by the rotating turbulent flow to form microdroplets, which increases the specific surface area of ​​the liquid and makes the contact between fluids A and B more sufficient. At the same time, the rotating turbulent flow causes the droplets to generate self-revolution coupling, which strengthens the internal self-circulation of the droplets and helps to improve the reaction efficiency of fluids A and B.

[0054] When the pre-rotating cyclone device 100 of this embodiment is used to capture carbon dioxide in flue gas, the flue gas is introduced into the pre-rotating cyclone device 100 as fluid A, and the absorbent (amine liquid) is introduced into the pre-rotating cyclone device 100 as fluid B. The rotating turbulence generated in the pre-rotating cyclone device 20 can effectively increase the specific surface area of ​​the absorbent and enhance the mass transfer between gas and liquid. The fluid passes through the pre-rotating unit 21, the fluid mixing unit 22 and the cyclone separation unit 23 in sequence. The flow path is long, and the contact and reaction time between substances is more sufficient. The cyclone separation unit 23 can separate the absorbent entrained in the purified flue gas, protecting the environment while reducing the amount of absorbent loss.

[0055] Example 2

[0056] like Figure 4 As shown, this embodiment provides a flue gas purification system, including three pre-rotating cyclone devices 100 as described in Embodiment 1. The three pre-rotating cyclone devices 100 are a water washing dust removal device 100a, a pollutant absorption device 100b, and an absorbent regeneration device 100c. Using the same devices in the water washing dust removal, pollutant absorption, and absorbent regeneration stages can reduce operating costs. The structure of the pre-rotating cyclone device 100 can achieve high efficiency in both dust removal and desorption operations.

[0057] The first radial inlet 13 of the water washing dust removal device 100a is used to introduce the flue gas to be treated, and the second radial inlet 14 is used to introduce washing water; the first radial inlet 13 of the pollutant absorption device 100b is connected to the gas outlet 11 of the water washing dust removal device 100a, and the liquid outlet 12 of the pollutant absorption device 100b is connected to the first radial inlet 13 of the absorbent regeneration device 100c; the liquid outlet 12 of the absorbent regeneration device 100c is connected to the second radial inlet 14 of the pollutant absorption device 100b. The flue gas purification system also includes a reboiler 201 and an outer cylinder 10 of the absorbent regeneration device 100c. An additional bypass liquid outlet 19 is provided at the bottom, which is connected to the inlet of the reboiler 201. The outlet of the reboiler 201 is connected to the second radial inlet 14 of the absorbent regeneration device 100c. Heat exchangers 202 are installed on two passages between the liquid outlet 12 of the pollutant absorption device 100b and the first radial inlet 13 of the absorbent regeneration device 100c, and between the liquid outlet 12 of the absorbent regeneration device 100c and the second radial inlet 14 of the pollutant absorption device 100b. A microchannel separator 203 is also provided outside the second radial inlet 14 of the pollutant absorption device 100b.

[0058] Specifically, the flue gas purification system also includes a water tank 204 connected to the liquid outlet 12 and the second radial inlet 14 of the water washing dust removal device 100a. The water tank can hold recycled washing water. A liquid pump 205 is installed at the outlet of the water tank 204. Under the action of the liquid pump 205, the washing water flows from the water tank 204 into the water washing dust removal device 100a, and then flows out from the liquid outlet 12 of the water washing dust removal device 100a back to the water tank 204, forming a cycle. The water washing dust removal process can remove solid particles in the flue gas before the flue gas comes into contact with the absorbent and reacts, which can reduce the risk of system blockage and failure, reduce wear on subsequent flow parts, reduce operating noise, and extend the service life of the equipment.

[0059] An air pump 208 is provided in the passage between the gas outlet 11 of the water washing dust removal device 100a and the first radial inlet 13 of the pollutant absorption device 100b. The air pump 208 can assist the flue gas to circulate in the system and facilitate stable control of the gas flow rate entering the pollutant absorption device.

[0060] Heat exchanger 202 enables heat exchange between the rich and lean absorbent solutions flowing through it, recovering heat from the lean solution for heating the rich solution, effectively reducing system energy consumption and improving energy utilization. In this embodiment, heat exchanger 202 adopts a novel plate heat exchanger, which, compared to traditional tubular heat exchangers, has advantages such as high heat exchange efficiency, low heat loss, compact and lightweight structure, small footprint, and long service life. A liquid pump 205 is installed on each of the two passages through heat exchanger 202 to assist fluid flow in the system, increase flow rate, and ensure stable system operation.

[0061] The microchannel separator 203 can adopt an existing structure. In this embodiment, the microchannel separator 203 is a cross-flow nanofiltration microchannel separator as described in CN115180744A. The equivalent diameter of the particulate filter media used in the microchannel separator 203 is 0.21 mm to 0.4 mm, which filters out particulate matter in the absorbent and reduces the risk of equipment clogging.

[0062] The flue gas purification system also includes a microcyclone separator 206 connected to the gas outlet 11 of the absorbent regeneration device 100c and the inlet of the reboiler 201. The microcyclone separator 206 is used to separate the small amount of absorbent liquid entrained in the gaseous pollutants, reduce absorbent loss, and increase the number of times the absorbent can be recycled.

[0063] A water cooler 207 is installed on the passage between the absorbent regeneration device 100c and the micro cyclone separator 206, and on the passage between the heat exchanger 202 and the microchannel separator 203, respectively, to cool down the gas and liquid generated after the absorbent is regenerated at high temperature, thereby improving the safety and stability of the system operation.

[0064] The flue gas purification system of this embodiment can be used to capture gaseous pollutants such as carbon dioxide and hydrogen sulfide in flue gas. The corresponding absorbent is amine liquid, such as monoethanolamine (MEA), diethanolamine (DEA), diisopropanolamine (DIPA), N-methyldiethanolamine (MDEA), etc. These absorbents can be regenerated by heating to achieve the recycling of absorbents.

[0065] For sulfur dioxide pollutants in flue gas, alkaline (alkali metal salt) solutions such as NaOH, Na2CO3, and Na2SO3 are typically used as absorbents. These absorbents cannot be directly regenerated by heating. Furthermore, the flue gas purification system also includes a dosing tank 209 connected to the second radial inlet 14 of the absorbent regeneration device 100c. A liquid pump 205 is installed in the passage between the dosing tank 209 and the absorbent regeneration device 100c to pump the liquid absorbent. Additionally, a valve can be installed in the passage between the dosing tank 209 and the absorbent regeneration device 100c as needed. The valve can be closed to block the passage when no dosing is required. Alternatively, the dosing tank 209 and the pump 205 can be detachable; if the absorbent does not require regeneration, it does not need to be connected to the absorbent regeneration device 100c. When the flue gas purification system is used to capture sulfur dioxide in flue gas, slurries such as CaCO3 and Ca(OH)2 can be added to the dosing tank as agents to assist in the regeneration of the absorbent. This allows the slurry to react with the desulfurization waste liquid that has absorbed SO2 in the absorbent regeneration device 100c to generate CaSO3, thereby regenerating the absorbent.

[0066] Example 3

[0067] like Figure 4 , 5 As shown, this embodiment provides a flue gas purification method, which uses the flue gas purification device of Embodiment 2, and includes:

[0068] Water washing dust removal process: The flue gas to be treated and the washing water are passed into the water washing dust removal device 100a. The water washing dust removal device 100a is used to shake and wash the particulate matter in the flue gas. The washing water and particulate matter are discharged into the water tank 204. The flue gas flows to the pollutant absorption device 100b.

[0069] Pollutant absorption stage: The absorbent filtered by the microchannel separator 203 is introduced into the pollutant absorption device 100b, where it comes into contact with and reacts with the pollutants in the flue gas. The purified gas after removing the pollutants is discharged, and the rich liquid of the absorbent that has absorbed the pollutants flows to the absorbent regeneration device 100c after being heated by the heat exchanger 202.

[0070] Absorbent regeneration stage: Simultaneously, the rich absorbent solution enters the absorbent regeneration device 100c, while the lean absorbent solution, heated by the reboiler 201, is also introduced into the absorbent regeneration device 100c and mixed with it. The rich and lean absorbent solutions react at high temperature, regenerating the rich solution into a lean solution. A portion of the regenerated lean absorbent solution flows to the reboiler 201 for heating, used for absorbent regeneration. The other portion of the lean absorbent solution, after cooling by exchanging heat with the rich solution in the heat exchanger 202, returns to the pollutant absorption device 100b for the absorption of pollutants in the flue gas.

[0071] Furthermore, the flue gas purification method also includes a gas drying step: the high-concentration pollutant gas released during absorbent regeneration enters the micro-cyclone separator 206, where it separates a small amount of absorbent entrained in the pollutant gas, resulting in dried pollutant gas, which facilitates the subsequent utilization of the high-concentration pollutant gas. The separated absorbent flows into the reboiler 201 for heating, which reduces absorbent loss and increases the number of absorbent cycles.

[0072] Specifically, this embodiment takes the capture of carbon dioxide in flue gas as an example, and uses amine liquid as the absorbent. In the pollutant absorption stage, the temperature of the absorbent is 15℃~60℃, and the velocity of the flue gas entering the first tangential feed channel 213 in the pollutant absorption device 100b is greater than 30m / s. In the absorbent regeneration stage, when the absorbent enters the pre-rotating cyclone 20 of the absorbent regeneration device 100c, the temperature of the rich absorbent solution is 30℃~60℃, and the temperature of the lean absorbent solution is 50℃~70℃. After being cooled by the heat exchanger 202, the temperature of the regenerated lean solution is 35℃~55℃.

[0073] Furthermore, if the absorbent used to treat pollutants requires additional chemical addition for regeneration, the chemical and the absorbent lean liquid flowing out after being heated by the reboiler 201 are introduced together from the second radial inlet 14 into the third outer chamber 17 of the absorbent regeneration device 100c, and then enter the cylindrical absorption chamber 211 through the liquid inlet holes 2111 on each of the pre-rotating hydrocyclones 20. The chemical, absorbent lean liquid and absorbent rich liquid in the cylindrical absorption chamber 211 come into contact and react, so that the absorbent rich liquid is regenerated into lean liquid.

[0074] Example 4

[0075] The inventors verified the effectiveness of the invention through the following experiments. However, it should be understood that these experimental configurations are for illustrative purposes only and do not constitute a limitation on the scope of the invention. Test methods not specifically specified in the following descriptions are generally performed under conventional conditions or as recommended by the manufacturer.

[0076] An experiment was conducted using the flue gas purification system of Example 2 to capture CO2 gas with amine solution. The specific experimental results are recorded below:

[0077] 1. Experimental conditions

[0078] Flue gas properties: The flue gas used in this experiment was taken from the waste gas produced in an industrial plant in Zhejiang Province. Its composition is shown in Table 1 below:

[0079] Table 1

[0080] type <![CDATA[Flow rate (Nm 3 / h)]]> <![CDATA[CO2(%)]]> <![CDATA[N2(%)]]> <![CDATA[H2O(%)]]> flue gas 320000 13.6 74.5 7.5

[0081] The absorbent used in the experiment was a 20% concentration monoethanolamine absorbent.

[0082] 2. Experimental Procedure

[0083] First, with 320000 Nm 3 Flue gas is introduced into the water washing dust removal device 100a at a flow rate of / h, while water washing water is introduced at a flow rate of 1200m³ / h. 3 A flow rate of [amount] / h enters the water washing dust removal device 100a and comes into contact with the flue gas. The rotating turbulence generated by the flue gas breaks up and atomizes the washing water, allowing for full contact between the gas and liquid. Particulate impurities are mixed into the washing water, thus achieving dust removal from the gas. After water washing dust removal, the washing water is discharged back to the water tank 204, and the flue gas is discharged into the pollutant absorption device 100b.

[0084] The flue gas after dust removal has a flux of 320,000 Nm³. 3 / h enters the pollutant absorption device 100b, and simultaneously, the absorbent (lean amine solution) at 45°C is introduced at 1200m 3 The amine solution enters the pollutant absorption device 100b and comes into contact with the flue gas. After the lean amine solution is broken and atomized, the amine droplets generate high-speed self-revolutionary motion in the cyclone separator. At the same time, the gas-liquid contact area increases and the internal self-circulation of the droplets is strengthened, which enhances the absorption of CO2 in the flue gas. The purified flue gas after removing CO2 is discharged, and the rich amine solution that has absorbed CO2 flows into the absorbent regeneration device 100c.

[0085] The amine-rich solution is heated to 55°C by heat exchanger 202 and then enters the absorbent regeneration unit 100c at a flow rate of 1600 m³ / s. 3 / h; simultaneously, the lean amine solution heated by reboiler 201 is kept at a temperature of 100℃ and a flow rate of 400m 3 The flow rate is / h. It enters the absorbent regeneration device 100c and exchanges heat with the rich amine liquid. The temperature of the mixed amine liquid in the pre-rotating hydrocyclone 20 is about 60°C. The rich amine liquid is regenerated to obtain a lean amine liquid and releases a high concentration of CO2.

[0086] Part of the regenerated lean amine solution is returned to the pollutant absorption unit 100b to absorb CO2 in the flue gas; the remainder enters the reboiler 201 for the regeneration of the rich amine solution. Specifically, the lean amine solution returning to the pollutant absorption unit 100b first passes through the heat exchanger 202 to reduce its temperature to 45°C, then enters the microchannel separator 203 to remove fine particulate pollutants, and finally enters the pollutant absorption unit 100b.

[0087] 3. Experimental Results

[0088] The composition of the exhaust gas generated during the entire experiment is shown in Table 2 below:

[0089] Table 2

[0090] type <![CDATA[Flow rate (Nm 3 / h)]]> <![CDATA[CO2(%)]]> <![CDATA[N2(%)]]> <![CDATA[H2O(%)]]> Purify flue gas 320000 2.7 74.5 18.4 <![CDATA[High-concentration CO2]]> 33000 99.5 0.3 0.2

[0091] As shown in Tables 1 and 2, after purification, the CO2 concentration in the flue gas decreased from 13.6% to 2.7%, with a removal efficiency of 80.15%. The high-concentration CO2 gas generated by amine desorption reached a CO2 concentration of 99.5%, making it usable. In this embodiment, the lean amine solution regenerated from the rich amine solution continued to absorb CO2, and its absorption efficiency did not fluctuate significantly.

[0092] In summary, the pre-rotating cyclone device, flue gas purification system, and flue gas purification method of the present invention can achieve good pollutant removal effect, and the equipment occupies a small area, with little amine liquid loss, long gas-liquid contact time, and high absorption reaction efficiency, thus achieving a more ideal flue gas purification effect.

[0093] The above embodiments are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention.

Claims

1. A pre-rotating cyclone device, characterized in that, It includes an outer cylinder, multiple pre-rotating cyclones located inside the outer cylinder and connected in parallel, and upper, middle, and lower baffles arranged from top to bottom inside the outer cylinder, wherein: The outer cylinder has a gas outlet at the top and a liquid outlet at the bottom. A first radial inlet is provided on the cylinder wall between the upper partition and the middle partition, and a second radial inlet is provided on the cylinder wall between the middle partition and the lower partition. The pre-rotating cyclone separator includes a pre-rotating unit, a fluid mixing unit, and a cyclone separation unit connected in sequence. The pre-rotating unit includes a vertically arranged cylindrical absorption chamber, a mandrel arranged along the centerline of the cylindrical absorption chamber, and a first tangential feed channel connected to the upper part of the cylindrical absorption chamber, located between an upper partition and a middle partition. The cylindrical absorption chamber passes through the middle partition and a lower partition, with several liquid inlet holes formed on the cavity wall between the middle and lower partitions. The fluid mixing unit includes a cylindrical mixing chamber arranged laterally below the lower partition and several guide vanes disposed within the cylindrical mixing chamber. The cyclone separation unit includes an upper cylindrical separation chamber, a lower conical separation chamber, a top overflow pipe, and a bottom underflow pipe arranged coaxially. The outlet of the cylindrical mixing chamber is tangentially connected to the upper cylindrical separation chamber. The outlet of the overflow pipe is located above the upper partition, and the outlet of the underflow pipe is located below the lower partition. The upper, middle, and lower partitions are spaced apart, and the edges of the partitions are sealed to the inner wall of the outer cylinder, thereby dividing the interior of the outer cylinder into four independent spaces.

2. The pre-rotating cyclone device according to claim 1, characterized in that: The fluid mixing unit also includes a fixed rod disposed on the center line of the cylindrical mixing cavity. Two guide vanes form a group, and several groups of guide vanes are arranged along the length of the fixed rod. Two guide vanes in the same group are disposed opposite each other on both sides of the fixed rod and are inclined in opposite directions, intersecting and staggering each other.

3. A flue gas purification system, characterized in that, The device includes three pre-rotating cyclone devices as described in any one of claims 1-2, wherein the three pre-rotating cyclone devices are respectively a water washing dust removal device, a pollutant absorption device, and an absorbent regeneration device, wherein: The first radial inlet of the water washing dust removal device is used to introduce the flue gas to be treated, and the second radial inlet is used to introduce the washing water. The first radial inlet of the pollutant absorption device is connected to the gas outlet of the water washing dust removal device, and the liquid outlet of the pollutant absorption device is connected to the first radial inlet of the absorbent regeneration device. The liquid outlet of the absorbent regeneration device is connected to the second radial inlet of the pollutant absorption device; The flue gas purification system also includes a reboiler, and the bottom of the absorbent regeneration device is provided with a bypass liquid outlet, which is connected to the reboiler inlet, and the reboiler outlet is connected to the second radial inlet of the absorbent regeneration device. Heat exchangers are installed in two passages between the liquid outlet of the pollutant absorption device and the first radial inlet of the absorbent regeneration device, and between the liquid outlet of the absorbent regeneration device and the second radial inlet of the pollutant absorption device. A microchannel separator is also provided outside the second radial inlet of the pollutant absorption device.

4. The flue gas purification system according to claim 3, characterized in that, Also includes: A water tank is connected to the liquid outlet and the second radial inlet of the water washing dust removal device, and a liquid pump is provided at the outlet of the water tank.

5. The flue gas purification system according to claim 3, characterized in that: The heat exchanger is a plate heat exchanger, and a liquid pump is installed on each of the two passages through the heat exchanger.

6. The flue gas purification system according to claim 3, characterized in that: The microchannel separator is a cross-flow nanofiltration microchannel separator, and the equivalent diameter of the particulate filter media used in the microchannel separator is 0.21 mm to 0.4 mm.

7. The flue gas purification system according to claim 3, characterized in that, Also includes: A microcyclone separator is connected to the gas outlet of the absorbent regeneration device and the inlet of the reboiler. This microcyclone separator is used to separate small amounts of absorbent liquid entrained in gaseous pollutants.

8. The flue gas purification system according to claim 3, characterized in that, Also includes: A dosing tank is connected to the second radial inlet of the absorbent regeneration device, and a liquid pump is installed in the passage between the dosing tank and the absorbent regeneration device.

9. A method for purifying flue gas, characterized in that, Using the flue gas purification system of claim 3, including: Water washing dust removal process: The flue gas to be treated and the washing water are passed into the water washing dust removal device to shake and wash the particulate matter in the flue gas. The washing water and particulate matter are discharged into the water tank and the flue gas flows to the pollutant absorption device. Pollutant absorption stage: The absorbent filtered by the microchannel separator is introduced into the pollutant absorption device, where it comes into contact with and reacts with the pollutants in the flue gas. The purified gas after removing the pollutants is discharged, and the rich liquid of the absorbent that has absorbed the pollutants flows to the absorbent regeneration device after being heated by the heat exchanger. Absorbent regeneration stage: At the same time as the rich absorbent solution enters the absorbent regeneration device, the lean absorbent solution heated by the reboiler is also introduced into the absorbent regeneration device and mixed with it. The rich absorbent solution and the lean absorbent solution react at high temperature, regenerating the rich solution into a lean solution. Part of the regenerated lean absorbent solution flows to the reboiler for heating, while the other part of the lean absorbent solution exchanges heat with the rich solution in the heat exchanger to cool down before returning to the pollutant absorption device.

10. The flue gas purification method according to claim 9, characterized in that: The flue gas purification system also includes a micro cyclone separator connected to the gas outlet of the absorbent regeneration device and the inlet of the reboiler; The flue gas purification method further includes a gas drying step: the high-concentration pollutant gas released during absorbent regeneration enters a micro-cyclone separator, which separates a small amount of absorbent entrained in the pollutant gas to obtain dry pollutant gas, and the separated absorbent flows into the reboiler for heating.

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