Efficient PVC particle-containing tail gas purification system and method

Abstract

The invention discloses an efficient PVC particle-containing tail gas purification system and method, and relates to the technical field of PVC treatment. A tangential tail gas inlet is formed in the middle of the side wall of the washing tower, a tail gas outlet is formed in the top, and a drain outlet is formed in the bottom; the input end of the first-stage venturi dust remover is connected to the output end of the cyclone separator; the second-stage venturi dust remover is coaxially arranged in the inner cavity of the washing tower, the top wall is hermetically connected with the top wall of the washing tower, the outer wall and the inner wall of the washing tower form an annular space, and the tangential tail gas inlet is communicated with the annular space; the water film generating device comprises a first group of water outlet holes formed in the inner wall of the washing tower in the annular space and a second group of water outlet holes formed in the outer wall of the secondary venturi dust remover; the particle intercepting layer is arranged above an air outlet of the second-stage Venturi dust remover; the airflow uniform distributor is arranged above the particle interception layer; and the spraying device comprises water injection nozzles which are symmetrically arranged at the upper end and the lower end of the demister. According to the system, PVC particles and impurities in tail gas are effectively removed through multi-stage purification, and the purification efficiency is high.

Description

Technical Field

[0001] The present application relates to the technical field of PVC treatment, and in particular to a highly efficient system and method for purifying tail gas containing PVC particles. Background Art

[0002] At present, polyvinyl chloride (PVC) occupies an important position and is widely used in many fields such as building materials, wire and cable manufacturing due to its good corrosion resistance, weather resistance and insulation properties.

[0003] However, the environmental problems caused by the PVC production process cannot be ignored. The PVC particles contained in the exhaust gas produced during production can cause harm to environmental health. At present, there are many problems in the actual operation of the equipment used to produce PVC. For example, the eight-cyclone separator is prone to sticking and bridging due to temperature influence, resulting in poor separation. The two-cyclone separator cannot discharge the material smoothly when the static electricity of the PVC resin is too large, which causes the exhaust gas to carry the material. The exhaust gas flows into the washing tower at a too fast flow rate, affecting the purification efficiency. These situations will increase the content of PVC particles in the exhaust gas flowing into the washing tower. At the same time, the traditional washing tower itself is also difficult to completely separate the PVC particles in the exhaust gas, which not only causes air pollution, but also leads to the loss of some PVC raw materials. Therefore, it is urgent to develop a high-efficiency exhaust gas washing tower equipment to solve the above problems. Summary of the Invention

[0004] The embodiments of the present application solve the problems raised in the background technology by providing an efficient system and method for purifying exhaust gas containing PVC particles.

[0005] In a first aspect, the embodiments of the present application provide an efficient exhaust gas purification system containing PVC particles, comprising: The scrubber has a tangential tail gas inlet in the middle of the side wall, a tail gas outlet at the top, and a sewage outlet at the bottom; A first-stage Venturi dust collector, the input end of which is connected to the output end of the cyclone separator, and is used to condense PVC particles in the exhaust gas through the scrubbing liquid, and the output end of which is connected to the tangential exhaust gas inlet; a secondary venturi dust collector, coaxially disposed in the inner cavity of the scrubber, with its top wall sealedly connected to the inner wall of the scrubber, its outer wall and the inner wall of the scrubber forming an annular space, and the tangential exhaust gas inlet communicating with the annular space; a water film generating device, comprising a first set of water outlet holes provided on the inner wall of the washing tower in the annular space and a second set of water outlet holes on the outer wall of the secondary venturi dust collector; a particle interception layer, disposed above the air outlet of the secondary Venturi dust collector; an air flow distributor, arranged above the particle interception layer; Multi-stage demister, including bottom, middle and top wire meshes with increasing mesh density along the airflow direction; The spraying device comprises water spraying ports symmetrically arranged at the upper and lower ends of the demister.

[0006] In combination with the first aspect, in a possible implementation, the efficient PVC particle-containing exhaust gas purification system also includes a guide vane; the guide vane is arranged in the air inlet of the secondary Venturi dust collector, and the inclination angle of the guide vane is 15-30°, which is used to uniformly conduct the airflow field of the exhaust gas.

[0007] In combination with the first aspect, in a possible implementation, the spray direction of the first group of water spray holes and the second group of water spray holes of the water film generating device forms an angle of 90-120° with the exhaust gas cyclone direction.

[0008] In combination with the first aspect, in a possible implementation, the particle interception layer is a Pall ring layer, which is used to capture condensed particles discharged from the secondary Venturi dust collector.

[0009] In combination with the first aspect, in a possible implementation, the airflow distributor is a honeycomb guide plate, the pores of which are parallel to the airflow direction to suppress turbulence.

[0010] In combination with the first aspect, in a possible implementation, the bottom wire mesh is a flat structure, and the middle wire mesh and the top wire mesh are both arched structures.

[0011] In combination with the first aspect, in a possible implementation, the first-stage Venturi dust collector and the second-stage Venturi dust collector each include a convergent air intake pipe, a throat pipe, and a divergent pipe that are connected in sequence, and a washing liquid injector is provided in the throat pipe; The convergent air inlet pipe of the first-stage Venturi dust collector is connected to the output end of the cyclone separator, and the end of the divergent pipe of the first-stage Venturi dust collector away from the throat pipe is connected to the tangential exhaust gas inlet; The tapered air inlet pipe of the secondary Venturi dust collector is provided with guide vanes.

[0012] In combination with the first aspect, in a possible implementation, a spiral guide groove is provided in the throat of the first-stage Venturi dust collector, and the washing liquid injector is arranged along the tangential direction of the spiral guide groove.

[0013] In a second aspect, an embodiment of the present application provides an efficient method for purifying exhaust gas containing PVC particles, characterized in that it includes the efficient exhaust gas purification system containing PVC particles according to the first aspect or any possible embodiment of the first aspect, and the method includes: The tail gas containing PVC particles is condensed into particles through the first-stage Venturi dust collector; The tail gas is introduced into the scrubber tangentially through the tangential tail gas inlet in the middle of the side wall of the scrubber, and the tail gas treated by the first-stage Venturi dust collector is introduced into the scrubber tangentially; Under the action of tangential force, the exhaust gas forms a vortex in the scrubber and clings to the inner wall of the scrubber, rotating from top to bottom in the annular space formed by the inner wall of the scrubber and the outer wall of the secondary Venturi dust collector. At the same time, the water outlet of the water film generating device begins to discharge water, forming a bidirectional adsorption water film on the inner wall of the scrubber and the outer wall of the secondary Venturi dust collector. During the exhaust gas rotation process, the water film fully contacts the exhaust gas, and the adhesive force of the water film adsorbs and condenses some PVC particles in the exhaust gas. The adsorbed PVC particles flow downward along the inner wall of the scrubber and the outer wall of the secondary venturi dust collector along with the water film, and are finally discharged through the sewage outlet at the bottom of the scrubber; The exhaust gas, after rotating and descending through the annular space, enters the interior of the secondary Venturi dust collector from the air inlet. In the secondary Venturi dust collector, the remaining PVC particles in the exhaust gas undergo secondary condensation, further increasing the particle size of the PVC particles. The upward airflow after being processed by the secondary Venturi dust collector carries some condensed PVC particles up to the particle interception layer, where the condensed particles are captured. The upward airflow continues to rise and passes through the airflow distributor installed above the particle interception layer, which evenly distributes the airflow and suppresses turbulence, so that the airflow enters the multi-stage demister with mesh density increasing along the airflow direction in a stable and uniform state for gradient filtration. The spray device flushes the intercepted particles to the sewage outlet; The clean exhaust gas after purification is discharged through the exhaust gas outlet.

[0014] One or more technical solutions provided in the embodiments of this application have at least the following technical effects: When the efficient PVC particle-containing exhaust gas purification system of the embodiment of the present application is working, the PVC particle-containing exhaust gas enters the first-stage Venturi dust collector after preliminary treatment by the cyclone separator, and is condensed into larger particles by the washing liquid. Then, it enters the washing tower tangentially through the tangential exhaust gas inlet, forming a vortex in the annular space. The first group of water outlet holes and the second group of water outlet holes of the water film generating device discharge water to form a reverse water film to adsorb the particles and discharge them through the sewage outlet. The exhaust gas enters the second-stage Venturi dust collector to condense the particles for a second time. The upward airflow passes through the particle interception layer to capture the particles. After being evenly distributed by the air flow distributor, it enters the multi-stage demister. The mesh density of the bottom screen, middle screen, and top screen increases gradually to achieve gradient filtration. The spray device flushes the particles intercepted by the demister screen to the sewage outlet. Finally, the clean exhaust gas is discharged from the exhaust outlet. This system effectively removes PVC particles and impurities in the exhaust gas through multi-stage purification, and has high purification efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following is a brief introduction to the drawings required for use in the description of the embodiments of the present application. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0016] Figure 1 A schematic diagram of the structure of an efficient exhaust gas purification system containing PVC particles provided in an embodiment of the present application; Figure 2 This is a schematic diagram of the structure of the tangential exhaust gas inlet provided in an embodiment of the present application.

[0017] Icons: 1-washing tower; 11-tangential exhaust gas inlet; 12-exhaust gas outlet; 13-sewage outlet; 2-first-stage Venturi dust collector; 3-second-stage Venturi dust collector; 4-water film generating device; 5-particle intercepting layer; 6-air flow distributor; 7-multi-stage demister; 71-bottom layer wire mesh; 72-middle layer wire mesh; 73-top layer wire mesh; 8-spraying device; 9-guide vane. DETAILED DESCRIPTION

[0018] The following will be combined with the accompanying drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.

[0019] In the description of the embodiments of the present application, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limitations on the present application. The terms "first", "second" and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. In addition, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be a communication between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0020] The present application embodiment provides an efficient exhaust gas purification system containing PVC particles, such as Figures 1 to 2 As shown. This efficient PVC particle exhaust gas purification system includes: The washing tower 1 is provided with a tangential tail gas inlet 11 in the middle of the side wall, a tail gas outlet 12 at the top, and a sewage outlet 13 at the bottom.

[0021] The first-stage Venturi dust collector 2 has an input end connected to the output end of the cyclone separator and is used to condense PVC particles in the exhaust gas through the scrubbing liquid, and the output end is connected to the tangential exhaust gas inlet 11.

[0022] The secondary venturi dust collector 3 is coaxially arranged in the inner cavity of the washing tower 1, with its top wall sealedly connected to the inner wall of the washing tower 1, its outer wall and the inner wall of the washing tower 1 forming an annular space, and the tangential exhaust gas inlet 11 is connected to the annular space.

[0023] The water film generating device 4 includes a first set of water outlet holes arranged on the inner wall of the washing tower 1 in the annular space and a second set of water outlet holes on the outer wall of the secondary venturi dust collector 3 .

[0024] The particle interception layer 5 is arranged above the air outlet of the secondary Venturi dust collector 3.

[0025] The air flow distributor 6 is arranged above the particle interception layer 5 .

[0026] The multi-stage demister 7 comprises a bottom layer wire mesh 71, a middle layer wire mesh 72 and a top layer wire mesh 73, the mesh density of which increases gradually along the airflow direction.

[0027] The spray device 8 comprises water spray ports symmetrically arranged at the upper and lower ends of the demister.

[0028] It should be noted that when this efficient exhaust gas purification system containing PVC particles is in operation, the exhaust gas containing PVC particles enters the first-stage Venturi dust collector 2 after preliminary treatment by the cyclone separator, and is condensed into larger particles using the washing liquid. It then enters the washing tower 1 tangentially through the tangential exhaust gas inlet 11, forming a vortex in the annular space. The first group of water outlet holes and the second group of water outlet holes of the water film generating device 4 discharge water to form a reverse water film to adsorb the particles and discharge them through the sewage outlet 13. The exhaust gas enters the second-stage Venturi dust collector 3 to condense the particles for a second time. The upward airflow passes through the particle interception layer 5 to capture the particles, and then enters the multi-stage demister 7 after being evenly distributed through the airflow distributor 6. The mesh density of the bottom screen 71, the middle screen 72, and the top screen 73 increases gradually to achieve gradient filtration. The spray device 8 flushes the particles intercepted by the demister screen to the sewage outlet 13. Finally, the clean exhaust gas is discharged from the exhaust outlet 12. This system effectively removes PVC particles and impurities in the exhaust gas through multi-stage purification, and has high purification efficiency.

[0029] In the embodiment of the present application, the efficient PVC particle-containing exhaust gas purification system further includes guide vanes 9. These vanes are positioned within the air inlet of the secondary Venturi dust collector 3. The guide vanes 9 have an inclination angle of 15-30° and are used to uniformly distribute the exhaust gas flow field. These guide vanes reorganize the exhaust gas flow field, which may otherwise be uneven, contain high-speed and low-speed areas, vortices, or biased flow.

[0030] It should be noted that a guide blade 9 with an inclination angle of 15-30° is arranged in the air inlet of the secondary Venturi dust collector 3, which can cleverly guide the airflow field of the exhaust gas entering the secondary Venturi dust collector 3 evenly, avoiding local turbulence or uneven flow rate in the airflow, so that the exhaust gas is mixed with the washing liquid in the secondary Venturi dust collector 3 more fully and evenly, further improving the effect of secondary condensation of PVC particles, enhancing the removal ability of the entire exhaust gas purification system for PVC particles, and helping to improve the quality and efficiency of exhaust gas purification.

[0031] In the embodiment of the present application, the spray direction of the first and second groups of water spray holes in the water film generating device 4 forms an angle of 90-120 degrees with the direction of the exhaust gas vortex. This design allows the sprayed water to fully contact the exhaust gas with a greater impact force, effectively enhancing the water film's adsorption of PVC particles and other impurities in the exhaust gas, improving the water film's efficiency in capturing pollutants. It also promotes uniform distribution of the water film within the annular space, enhancing the cleaning effect on the inner wall of the scrubber tower 1 and the outer wall of the secondary venturi dust collector 3, further improving the purification efficiency of the exhaust gas purification system.

[0032] In the embodiment of the present application, the particle interception layer 5 is a ball ring layer, which is used to capture the agglomerated particles discharged from the secondary venturi dust collector 3. Specifically, the surface of the ball ring layer is provided with an anti-stick coating. The anti-stick coating is a polytetrafluoroethylene coating.

[0033] It should be noted that the particle interception layer 5 adopts a ball ring layer. The ball ring layer has a large specific surface area and good fluid distribution performance, which can significantly increase the contact area between the airflow and the ball ring layer, so that the condensed particles discharged from the secondary Venturi dust collector 3 are easier to be captured when passing through, thereby improving the particle interception efficiency, and effectively preventing the condensed particles that have not been completely removed from entering the subsequent purification link with the airflow, avoiding the accumulation of particles in subsequent equipment to cause blockage or affect the purification effect, thereby ensuring the stable and efficient operation of the entire exhaust purification system, and ensuring that the quality of the exhaust gas finally discharged meets environmental protection requirements.

[0034] In the embodiment of the present application, the airflow distributor 6 is a honeycomb guide plate, the pores of which are parallel to the airflow direction to suppress turbulence.

[0035] It should be noted that the airflow distributor 6 is configured as a honeycomb guide plate with the duct parallel to the airflow direction. This design can cleverly organize and guide the airflow, making the originally turbulent airflow stable and uniform, effectively suppressing the generation of turbulence. The uniform and stable airflow enters the subsequent purification process such as the demister, which can significantly improve the efficiency and quality of the defoaming and other purification operations, ensure that the droplets and particles in the exhaust gas are more fully removed, avoid the purification dead corners caused by uneven airflow, and thus improve the purification effect and operational reliability of the entire PVC particle-containing exhaust gas purification system.

[0036] In the embodiment of the present application, the bottom screen 71 is a flat structure, and the middle screen 72 and the top screen 73 are both arched structures.

[0037] It should be noted that the bottom screen 71 adopts a flat structure, which can preliminarily and smoothly intercept larger particle droplets and particles in the airflow, playing a basic filtering role; the middle screen 72 and the top screen 73 are designed as an arch structure. On the one hand, it increases the contact area with the airflow, extends the airflow path, and gives small particle droplets and particles in the airflow more opportunities to be intercepted. On the other hand, the arch structure can guide the airflow to be evenly distributed, avoiding local airflow that is too fast and resulting in incomplete defoaming, thereby improving the gradient filtration effect of the multi-stage defoamer 7 on droplets and particles in the exhaust gas, and improving the exhaust gas purification quality.

[0038] In the embodiment of the present application, both the primary and secondary Venturi dust collectors 2 and 3 include a sequentially connected converging inlet pipe, a throat pipe, and a diverging pipe, with a scrubbing liquid injector disposed within the throat pipe. The converging inlet pipe of the primary Venturi dust collector 2 is connected to the output of the cyclone separator, while the diverging pipe of the primary Venturi dust collector 2, at the end remote from the throat pipe, is connected to the tangential exhaust gas inlet 11. Guide vanes 9 are disposed within the converging inlet pipe of the secondary Venturi dust collector 3.

[0039] It should be noted that both the first-stage Venturi dust collector 2 and the second-stage Venturi dust collector 3 adopt a structure in which a tapered air inlet pipe, a throat pipe and a diverging pipe are connected in sequence, and a washing liquid injector is provided in the throat pipe. This design enables the exhaust gas to accelerate in the tapered air inlet pipe, the throat pipe and the washing liquid to fully mix and condense the particles, and the diverging pipe to decelerate, thereby effectively enhancing the condensation effect on PVC particles; the tapered air inlet pipe of the first-stage Venturi dust collector 2 is connected to the output end of the cyclone separator, and the diverging pipe is connected to the tangential exhaust gas inlet 11, so as to realize the orderly transportation of the exhaust gas and the connection with the subsequent treatment; the guide blades 9 are provided in the tapered air inlet pipe of the second-stage Venturi dust collector 3, which can evenly guide the exhaust gas, so that it can be mixed more fully with the washing liquid, thereby improving the secondary condensation efficiency, and thereby comprehensively improving the removal ability and purification effect of the entire exhaust gas purification system for PVC particles.

[0040] In the embodiment of the present application, a spiral guide groove is provided in the throat of the first-stage Venturi dust collector 2, and the washing liquid injector is arranged along the tangential direction of the spiral guide groove.

[0041] It should be noted that the spiral guide groove guides the exhaust gas into a spiral flow, increasing its residence time and turbulence within the throat, ensuring more complete contact and more uniform mixing between the scrubbing liquid and the exhaust gas. The placement of the scrubbing liquid injector tangentially along the spiral guide groove further enhances this spiral flow effect, ensuring that the scrubbing liquid is precisely injected into the core area of ​​the exhaust gas flow, thereby enhancing the scrubbing liquid's wetting, adsorption, and agglomeration effects on the PVC particles.

[0042] The embodiment of the present application provides an efficient method for purifying tail gas containing PVC particles, characterized in that it includes the above-mentioned efficient tail gas purification system containing PVC particles, and the method includes: S1: The tail gas containing PVC particles is condensed into particles through the first-stage Venturi dust collector 2.

[0043] It should be noted that exhaust gas containing PVC particles is introduced into the primary Venturi dust collector 2, where it is accelerated through a converging inlet pipe and then enters the throat pipe. At the throat pipe, a scrubbing liquid injector sprays scrubbing liquid at a specific pressure and flow rate into the airflow at high speed, thoroughly mixing and violently colliding the scrubbing liquid and exhaust gas. The scrubbing liquid's wetting, adsorption, and agglomeration properties cause the PVC particles in the exhaust gas to collide and bond with each other, agglomerating into particles larger than 50 μm. After being decelerated through a diverging pipe, the exhaust gas is then tangentially introduced through the diverging pipe into the tangential exhaust gas inlet 11 of the scrubbing tower 1.

[0044] S2: The tail gas is introduced into the washing tower 1 tangentially through the tail gas inlet 11 in the middle of the side wall of the washing tower 1, and the tail gas treated by the first-stage venturi dust collector 2 is introduced into the washing tower 1 tangentially.

[0045] S3: Under the influence of tangential forces, the exhaust gas forms a vortex within scrubber 1. It clings closely to the inner wall of scrubber 1 and rotates downward in the annular space formed by the inner wall of scrubber 1 and the outer wall of secondary Venturi dust collector 3. Simultaneously, the outlet holes of water film generating device 4 begin to discharge water, forming a bidirectional adsorption water film on the inner wall of scrubber 1 and the outer wall of secondary Venturi dust collector 3. During this swirling motion of the exhaust gas, the water film fully contacts the exhaust gas, utilizing its adhesive force to absorb and condense some of the PVC particles in the exhaust gas.

[0046] S4: The adsorbed PVC particles flow downward along the inner wall of the washing tower 1 and the outer wall of the secondary venturi dust collector 3 along with the water film, and are finally discharged through the sewage outlet 13 at the bottom of the washing tower 1.

[0047] S5: The tail gas after rotating and descending through the annular space enters the interior of the secondary venturi dust collector 3 from the air inlet. In the secondary venturi dust collector 3, the remaining PVC particles in the tail gas are subjected to secondary condensation, so that the particle size of the PVC particles is further increased.

[0048] It should be noted that in the secondary Venturi dust collector 3, the exhaust gas undergoes the process of acceleration, mixing and condensation again, and the washing liquid is further sprayed at the throat to perform secondary condensation on the remaining PVC particles in the exhaust gas, so that the particle size is further increased, thereby improving the efficiency of subsequent separation.

[0049] S6: The upward airflow after being processed by the secondary Venturi dust collector 3 carries part of the condensed PVC particles and rises to the particle interception layer 5, where the condensed particles are captured.

[0050] It should be noted that the particle interception layer 5 is a ball ring layer, which has a large specific surface area and good fluid distribution performance. It can increase the contact area between the airflow and the ball ring layer, effectively capture the condensed particles discharged from the secondary Venturi dust collector 3, and prevent the particles from entering the subsequent purification link with the airflow.

[0051] S7: The upward airflow continues to rise and passes through the airflow distributor 6 arranged above the particle interception layer 5, which evenly distributes the airflow and suppresses turbulence, so that the airflow enters the multi-stage demister 7 with a mesh density increasing along the airflow direction in a stable and uniform state for gradient filtration, and the spray device 8 flushes the retained particles to the sewage outlet 13.

[0052] It should be noted that the airflow distributor 6 is a honeycomb guide plate, the channels of which are parallel to the airflow direction, which can evenly distribute the airflow, suppress turbulence, and allow the airflow to enter the subsequent demister in a stable and uniform state, thereby improving the defoaming effect.

[0053] The spraying device 8, symmetrically arranged at the upper and lower ends of the multi-stage demister 7, starts working to flush the particles and droplets trapped by the multi-stage demister 7, causing them to separate from the multi-stage demister 7 and flow along with the water flow to the sewage outlet 13. The spraying device 8 of the present application is provided with four groups of water outlets, two groups each at the upper and lower ends of the demister.

[0054] S8: The clean exhaust gas is discharged through the exhaust outlet 12. PVC particles and other impurities have been effectively removed, resulting in clean exhaust gas. The clean exhaust gas is discharged into the atmosphere through the exhaust outlet 12 at the top of the scrubber 1.

[0055] It should be noted that the high-efficiency PVC particle-containing exhaust gas purification method of the present application, with the help of a unique purification system, uses the first-level Venturi dust collector 2 to efficiently condense PVC particles, and the tangential air intake causes the exhaust gas to form a vortex in the washing tower 1 and fully contact with the bidirectional adsorption water film to adsorb the particles. The second-level Venturi dust collector 3 condenses the remaining particles for a second time, the Pall ring layer effectively captures the condensed particles, the honeycomb guide plate allows the airflow to enter the multi-stage demister 7 for gradient filtration evenly and stably, and the spray device 8 flushes the retained particles, ultimately achieving efficient removal of PVC particles and other impurities, and discharging clean exhaust gas, which significantly improves the exhaust gas purification efficiency and quality, ensures that emissions meet standards and the system operates stably and reliably.

[0056] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other. Each embodiment focuses on the differences from other embodiments.

[0057] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit the present application. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some or all of the technical features therein can be replaced by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present application.

Claims

1. An efficient tail gas purification system containing PVC particles, characterized in that: include: A washing tower (1) is provided with a tangential tail gas inlet (11) in the middle of the side wall, a tail gas outlet (12) at the top, and a sewage outlet (13) at the bottom; A first-stage Venturi dust collector (2), the input end of which is connected to the output end of the cyclone separator, and is used to condense PVC particles in the exhaust gas through a scrubbing liquid, and the output end of which is connected to the tangential exhaust gas inlet (11); A secondary Venturi dust collector (3) is coaxially arranged in the inner cavity of the scrubbing tower (1), the top wall of which is sealedly connected to the inner wall of the scrubbing tower (1), the outer wall of which forms an annular space with the inner wall of the scrubbing tower (1), and the tangential tail gas inlet (11) is connected to the annular space; A water film generating device (4) comprising a first set of water outlet holes arranged on the inner wall of the washing tower (1) and a second set of water outlet holes on the outer wall of the secondary venturi dust collector (3) in the annular space; A particle interception layer (5) is provided above the air outlet of the secondary Venturi dust collector (3); An airflow distributor (6) is arranged above the particle interception layer (5); A multi-stage demister (7) comprising a bottom screen (71), a middle screen (72), and a top screen (73) with increasing mesh density along the airflow direction; The spray device (8) comprises water spray ports symmetrically arranged at the upper and lower ends of the demister.

2. The efficient tail gas purification system containing PVC particles according to claim 1 is characterized in that: Also includes guide vanes (9); The guide vane (9) is arranged in the air inlet of the secondary Venturi dust collector (3), and the guide vane (9) has an inclination angle of 15-30 degrees, and is used to conduct the air flow field of the exhaust gas uniformly.

3. The efficient tail gas purification system containing PVC particles according to claim 1 is characterized in that: The spray direction of the first group of water spray holes and the second group of water spray holes of the water film generating device (4) forms an angle of 90-120° with the exhaust gas cyclone direction.

4. The efficient tail gas purification system containing PVC particles according to claim 1 is characterized in that: The particle interception layer (5) is a ball ring layer, which is used to capture condensed particles discharged from the secondary Venturi dust collector (3).

5. The efficient tail gas purification system containing PVC particles according to claim 1 is characterized in that: The airflow distributor (6) is a honeycomb guide plate, the pores of which are parallel to the airflow direction to suppress turbulence.

6. The efficient tail gas purification system containing PVC particles according to claim 1 is characterized in that: The bottom layer wire mesh (71) is a flat structure, and the middle layer wire mesh (72) and the top layer wire mesh (73) are both arched structures.

7. The efficient tail gas purification system containing PVC particles according to claim 2 is characterized in that: The first-stage Venturi dust collector (2) and the second-stage Venturi dust collector (3) both comprise a gradually converging air intake pipe, a throat pipe and a gradually diverging pipe that are connected in sequence, and a washing liquid injector is provided in the throat pipe; The converging air inlet pipe of the first-stage Venturi dust collector (2) is connected to the output end of the cyclone separator, and the end of the diverging pipe of the first-stage Venturi dust collector (2) away from the throat pipe is connected to the tangential exhaust gas inlet (11); A guide vane (9) is provided in the tapered air inlet pipe of the secondary Venturi dust collector (3).

8. The efficient tail gas purification system containing PVC particles according to claim 7 is characterized in that: A spiral guide groove is provided in the throat of the first-stage Venturi dust collector (2), and the washing liquid injector is arranged along the tangent direction of the spiral guide groove.

9. An efficient method for purifying tail gas containing PVC particles, characterized in that: The method comprises the efficient PVC particle-containing tail gas purification system according to any one of claims 1 to 8, wherein the method comprises: The tail gas containing PVC particles is condensed into particles by passing through a first-stage Venturi dust collector (2); The tail gas is introduced into the scrubbing tower (1) tangentially through the tail gas inlet (11) in the middle of the side wall of the scrubbing tower (1) after being treated by the first-stage venturi dust collector (2); Under the action of the tangential force, the exhaust gas forms a vortex in the washing tower (1) and closely adheres to the inner wall of the washing tower (1), rotating from top to bottom in the annular space formed by the inner wall of the washing tower (1) and the outer wall of the secondary venturi dust collector (3); at the same time, the water outlet of the water film generating device (4) starts to discharge water, forming a bidirectional adsorption water film on the inner wall of the washing tower (1) and the outer wall of the secondary venturi dust collector (3); during the exhaust gas rotation process, the water film fully contacts the exhaust gas, and utilizes the adhesive force of the water film to adsorb and condense some PVC particles in the exhaust gas; The adsorbed PVC particles flow downward along the inner wall of the washing tower (1) and the outer wall of the secondary venturi dust collector (3) along with the water film, and are finally discharged through the sewage outlet (13) at the bottom of the washing tower (1); The tail gas, after rotating and descending through the annular space, enters the interior of the secondary Venturi dust collector (3) from the air inlet thereof; in the secondary Venturi dust collector (3), the remaining PVC particles in the tail gas are subjected to secondary condensation, so that the particle size of the PVC particles is further increased; The upward airflow after being processed by the secondary Venturi dust collector (3) carries part of the condensed PVC particles and rises to the particle interception layer (5), where the condensed particles are captured by the particle interception layer (5); The upward airflow continues to rise and passes through the airflow distributor (6) disposed above the particle interception layer (5), which evenly distributes the airflow and suppresses turbulence, so that the airflow enters the multi-stage demister (7) with a mesh density increasing along the airflow direction in a stable and uniform state for gradient filtration. The spray device (8) flushes the intercepted particles to the sewage outlet (13); The clean exhaust gas after purification is discharged through the exhaust gas outlet (12).

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