CN213160210U

CN213160210U - VOC photocatalytic treatment system

Info

Publication number: CN213160210U
Application number: CN202020611278.3U
Authority: CN
Inventors: 杨彦松; 易争明
Original assignee: Xiangtan University
Current assignee: Xiangtan University
Priority date: 2020-04-22
Filing date: 2020-04-22
Publication date: 2021-05-11
Anticipated expiration: 2030-04-22

Abstract

The utility model provides a VOC photocatalysis treatment system, which comprises a catalysis treatment device, a precipitation device and a catalyst regeneration device, wherein the catalysis treatment device and the catalyst regeneration device are arranged above the precipitation device, the precipitation device is divided into a first precipitation area, a second precipitation area, a first clarification area, a second clarification area and a third clarification area, the bottom of the catalysis treatment device is provided with a first opening communicated with the precipitation device, the first opening is right opposite to the first precipitation area, the bottom of the catalyst regeneration device is provided with a second opening communicated with the precipitation device, the second opening is right opposite to the second precipitation area, the VOC photocatalysis treatment system also comprises a first pipe body vertically extending from the first opening towards the direction of the first precipitation area and a second pipe body vertically extending from the second opening towards the direction of the second precipitation area, the tail end of the first pipe body is immersed in the liquid surface of the first settling zone.

Description

VOC photocatalysis treatment system

Technical Field

The utility model relates to an organic waste gas handles technical field, especially relates to a VOC photocatalysis processing system.

Background

In industrial production, particularly in the printing industry, exhaust gas generated in the production process includes a large amount of Volatile Organic Compounds (VOC), and is emitted through the surface of a printing material and discharged outside a workshop through a pipeline without any treatment, thereby causing serious pollution to the atmospheric environment.

In the related art, organic waste gas treatment is generally selected from activated carbon adsorption, solution absorption recovery, condensation recovery, combustion oxidation, and the like, but in the treatment process of the above methods, a large amount of raw materials are consumed, and the requirement of low energy consumption cannot be met, therefore, a photocatalytic degradation technology is gradually used, which is based on the principle that radicals with extremely high activity are generated in a reaction system, and then the pollutants are completely degraded into inorganic substances through the processes of addition, substitution, electron transfer, and the like between the radicals and organic pollutants in the waste gas, and the inorganic substances are discharged after forming clean gas, so that the pollution reduction effect is good. The existing VOC photocatalytic treatment system for treating waste gas by utilizing a photocatalytic degradation technology generally comprises a catalytic treatment device, a precipitation device and a catalyst regeneration device, wherein a catalyst in the catalytic treatment device drops into the precipitation device for precipitation after treating the waste gas, the precipitated and layered catalyst is sent into the catalyst regeneration device for regeneration, and the precipitated clear liquid and the regenerated catalyst are returned to the catalytic treatment device in a proper proportion for waste gas treatment so as to realize recycling. However, after the catalytic decomposition reaction is completed, the mixture of the catalyst, the liquid and the gas in the catalytic treatment device directly falls into the precipitation device, the gas enters the catalyst regeneration device through the upper space of the precipitation device, and the gas is not sufficiently purified again by the catalyst at the bottom layer of the precipitation device.

Therefore, there is a need to provide a new VOC photocatalytic treatment system to solve the above problems.

SUMMERY OF THE UTILITY MODEL

Based on the above problem, the utility model provides a new VOC photocatalysis processing system.

The utility model provides a VOC photocatalysis treatment system, including catalytic treatment device, sediment device and catalyst regeneration device, catalytic treatment device with catalyst regeneration device install in sediment device's top and mutual interval, sediment device is separated into and is located first settling zone of catalytic treatment device below, is located the second settling zone of catalyst regeneration device below, is located first settling zone with first settling zone between the second settling zone, is located first settling zone keeps away from the second settling zone of first settling zone one side and is located the third settling zone that the second settling zone kept away from first settling zone one side, the height of second settling zone with the third settling zone all is less than the height of first settling zone, first settling zone with the third settling zone respectively through the pipeline with catalyst regeneration device connects, the first clarification area is respectively connected with the catalytic treatment device and the catalyst regeneration device through pipelines, the second clarification area and the second sedimentation area are connected with the catalytic treatment device through pipelines, the bottom of the catalytic treatment device is provided with a first opening communicated with the sedimentation device, the first opening is just opposite to the first sedimentation area, the bottom of the catalyst regeneration device is provided with a second opening communicated with the sedimentation device, the second opening is just opposite to the second sedimentation area, waste gas enters from the catalytic treatment device and is discharged from the catalyst regeneration device, the VOC photocatalytic treatment system further comprises a first pipe body vertically extending from the first opening towards the direction close to the first sedimentation area and a second pipe body vertically extending from the second opening towards the direction close to the second sedimentation area, the tail end of the first pipe body is immersed in the liquid surface of the first settling zone, and the tail end of the second pipe body is exposed out of the liquid surface of the second settling zone.

Preferably, the sediment device include the roof, with the relative diapire that sets up of roof, connection the roof with the lateral wall of diapire, be fixed in two baffles that diapire and mutual interval set up and be fixed in diapire and symmetry interval set up in two the first baffle and the second baffle of baffle both sides, the roof the diapire reaches the lateral wall cooperation forms accommodation space, the height of baffle, first baffle and second baffle is less than the height of lateral wall, first baffle, two baffles and second baffle cooperation will accommodation space separates the formation intercommunication from a left side to the right side in proper order second clarification area, first settling zone, first clarification area, second settling zone and third clarification area, catalytic treatment device with catalyst regeneration device install in the roof.

Preferably, the first partition board includes a first body portion vertically fixed to the bottom wall and a first extending portion extending from an end of the first body portion away from the bottom wall to a direction close to the bottom wall and located below the first tube, and the second partition board includes a second body portion vertically fixed to the bottom wall and a second extending portion extending from an end of the second body portion away from the bottom wall to a direction close to the bottom wall and located below the second tube.

Preferably, an orthographic projection of the first extension part towards the catalytic treatment device at least partially falls into the pipe orifice of the first pipe body, and an orthographic projection of the second extension part towards the catalytic treatment device at least partially falls into the pipe orifice of the second pipe body.

Preferably, an included angle between the first extending portion and the first body portion is 30-45 °, and an included angle between the second extending portion and the second body portion is 30-45 °.

Preferably, the lateral wall corresponds first play liquid hole has been seted up to the position of first settling zone, corresponds the second play liquid hole has been seted up to the position of first settling zone, corresponds the third play liquid hole has been seted up to the position of second settling zone, corresponds the fourth play liquid hole has been seted up to the position of second settling zone, corresponds the fifth play liquid hole has been seted up to the position of third settling zone, first play liquid hole, second go out liquid hole and the third go out liquid hole all set up in lateral wall bottom position, first go out liquid hole with the fifth play liquid hole respectively through the pipeline with catalyst regeneration device connects, the second go out liquid hole respectively with catalyst treatment device with catalyst regeneration device connects, the third go out liquid hole with the fourth go out liquid hole respectively through the pipeline with catalyst treatment device connects.

Preferably, catalytic treatment device including have the air inlet first casing, accept in first nozzle in the first casing and with the catalysis light source that first nozzle interval set up, waste gas by the air inlet gets into, first nozzle pass through the pipeline with second goes out liquid hole, third and goes out liquid hole and fourth and go out liquid hole intercommunication for drench and spout the treatment fluid, including the catalyst in the treatment fluid.

Preferably, the first nozzle is arranged in the direction opposite to the moving direction of the gas, and the catalyst is TiO₂。

Preferably, the catalyst regeneration device comprises a second shell with a gas outlet, a second nozzle contained in the second shell, a packing layer arranged below the second nozzle, a microwave device annularly arranged around the packing layer, a demisting layer fixed at one end of the second shell close to the gas outlet, and a mechanical baffle fixed at one end of the second shell close to the precipitation device, wherein the second nozzle and the packing layer are positioned between the demisting layer and the mechanical baffle, the treated gas is discharged from the gas outlet, the second nozzle is communicated with the first liquid outlet through a pipeline, and the direction of the second nozzle is opposite to the moving direction of the gas.

Compared with the prior art, the VOC photocatalytic treatment system provided by the utility model can enable the waste gas to contact and react with the catalyst again in the liquid by arranging the first pipe body with the tail end immersed in the liquid surface of the precipitation device at the first opening part communicated with the precipitation device, thereby enhancing the degradation effect; under the certain condition of the sedimentation device volume, a second clarification area and a third clarification area are additionally separated on the left side of a first sedimentation area and the right side of a second sedimentation area serving as a solid-liquid sedimentation area, the volumes of the first sedimentation area and the second sedimentation area can be compressed, the first sedimentation area and the second sedimentation area are made to be more narrow and long, the falling speed of a solid-phase catalyst is accelerated, and the second clarification area and the third clarification area can be used for supplementing the shortage of clear liquid of the first clarification area.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained without inventive work, wherein:

fig. 1 is a schematic block diagram of a VOC photocatalytic treatment system provided by the present invention;

fig. 2 is a schematic view of a part of the structure connection of the VOC photocatalytic treatment system provided by the present invention;

fig. 3 is a schematic view of the structure of the ultraviolet lamp shown in fig. 2.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

Referring to fig. 1 and 2, the present invention provides a VOC photocatalytic treatment system 100, which includes a catalytic treatment device 1, a precipitation device 2, a pipeline 3, a catalyst regeneration device 4, a first pipe 5 and a second pipe 6. The catalytic treatment device 1 and the catalyst regeneration device 4 are arranged above the precipitation device 2 and are spaced from each other, and the pipeline 3 is used for connecting various components of the VOC photocatalytic treatment system 100.

The catalytic treatment device 1 treats the waste gas by using a photocatalytic degradation technology, and the principle is that free radicals with extremely strong activity are generated in a reaction system, and then the pollutants are completely degraded into inorganic matters through the processes of addition, substitution, electron transfer and the like between the free radicals and organic pollutants in the waste gas, and the inorganic matters are discharged after forming clean gas, so that the catalytic treatment device has a good pollution reduction effect.

The catalytic treatment device 1 includes a first housing 11 having an accommodating space, a first nozzle 12 accommodated in the first housing 11, and a catalytic light source 13 accommodated in the first housing 11 and spaced apart from the first nozzle 12.

The first casing 11 is a hollow cylindrical structure, the top of the first casing is provided with an air inlet 111, waste gas to be treated enters the accommodating space from the air inlet 111 to complete catalytic degradation, and the bottom of the first casing is provided with a first opening 112 communicated with the precipitation device 2.

The top of the first casing 11 is provided with an air inlet 111, the bottom thereof is provided with a first opening 112, and the waste gas to be treated enters the accommodating space through the air inlet 111 to complete catalytic degradation.

The first nozzle 12 is used for spraying a treatment liquid, the treatment liquid contains a catalyst, and preferably, the catalyst is TiO₂It has the advantages of high activity, high stability, low cost, no toxicity, etc. The setting direction of the first nozzle 12 is opposite to the air flow movement direction, that is, the first nozzle 12 is arranged towards the air inlet 111, the treatment liquid sprayed out from the first nozzle 12 is upwards sprayed out in a spiral shape at a high speed and is directly contacted with the exhaust gas reversely entering the first shell 11, when the two-phase momentum reaches a balance, a section of standing wave area which is formed by foam and highly turbulent is formed, the contact area of the two phases of air and liquid in the standing wave area is large, the update frequency is high, and extremely high mass transfer efficiency and degradation effect can be obtained.

Furthermore, the treatment liquid sprayed out from the first nozzle 12 moves along the direction toward the gas inlet 111, and then descends under the action of gravity to form two sections of movement paths, so that the contact time of the catalyst and the waste gas can be prolonged, and the degradation effect can be enhanced.

Furthermore, the number of the first nozzles 12 is two, the two first nozzles 12 are spaced from each other, and the sum of the lifts of the two first nozzles 12 is equal to the height of the first shell 11 by adjusting the spraying force and the distance of the first nozzles 12, so that the treatment liquid is uniformly distributed in the accommodating space, the contact area between the waste gas and the treatment liquid is increased, and the degradation effect is further enhanced. In other embodiments, the number of the first nozzles 12 may be any other number, which is not limited by the present invention.

The catalytic light source 13 provides a light source for catalytic degradation reaction, and is fixedly connected with the first shell 11. Specifically, the catalytic light source 13 includes an ultraviolet lamp 131 and a power source 132 connected to the ultraviolet lamp 131, the ultraviolet lamp 131 is fixed to the inner wall of the first casing 11, and the power source 132 is disposed on the outer wall of the first casing 11. Further, the number of the catalytic light sources 13 is plural, the ultraviolet light sources 13 are spaced from each other, and the number of the catalytic light sources 13 can be adjusted according to the intensity of light required for the catalytic degradation reaction.

Referring to fig. 3, the ultraviolet lamp 131 includes a plurality of lamps 1311 and a transparent cover 1312 covering the lamps 1311, and the lamps 1311 are distributed in a ring array along a central axis of the first housing 11, which may ensure uniform distribution of light intensity in the accommodating space; the lamp cover 1312 plays a role in waterproofing, prevents the lamp tube 1312 from contacting the treatment liquid, and prolongs the service life of the lamp tube 1312.

The settling device 2 is a square or round box-shaped structure and comprises a top wall 21, a bottom wall 22 arranged opposite to the top wall 21, a side wall 23 connecting the top wall 21 and the bottom wall 22, two partition plates 24 fixed on the bottom wall 22 and spaced from each other, and a first partition plate 25 and a second partition plate 26 fixed on the bottom wall 22 and symmetrically arranged at two sides of the two partition plates 24 at intervals. The catalytic treatment apparatus 1 and the catalyst regeneration apparatus 4 are mounted on the ceiling wall 21, and the height of the partition plate 24, the first partition plate 25, and the second partition plate 26 is smaller than the height of the side wall 23.

The top wall 21, the bottom wall 22 and the side wall 23 cooperate to form a containing space, the first partition plate 25, the two partition plates 24 and the second partition plate 26 cooperate to sequentially partition the containing space from left to right to form a second clarification zone 40, a first sedimentation zone 10, a first clarification zone 20, a second sedimentation zone 30 and a third clarification zone 50 which are communicated with each other, the first settling zone 10 is located below the catalytic treatment unit 1, the second settling zone 30 is located below the catalyst regeneration unit 4, the first clarification zone 20 is located between the first settling zone 10 and the second settling zone 30, the second clarification zone 40 is located at the side of the first settling zone 10 remote from the first clarification zone 20, the third clarification zone 50 is located on the side of the second settling zone 30 remote from the first clarification zone 20, the height of both the second fining zone 40 and the third fining zone 50 is lower than the height of the first fining zone 20.

It is understood that after the catalytic decomposition reaction is completed, the catalyst surface in the treatment solution may be attached with particulate impurities in the exhaust gas or insoluble substances generated after the degradation reaction, the activity is reduced to form contaminated catalyst, the contaminated catalyst falls along with the treatment solution, enters the first settling zone 10 through the first opening 112 to settle, after the contaminated catalyst is accumulated to a certain extent, the liquid level in the first settling zone 10 rises, and the supernatant in the first settling zone 10 passes through the partition plate 24 and the first partition plate 25 to enter the first clarifying zone 20 and the second clarifying zone 40, respectively.

A first liquid outlet hole 231 is formed in the position, corresponding to the first settling zone 10, of the side wall 23; a second liquid outlet 232 is arranged at the position corresponding to the first clarification zone 20; a third liquid outlet 233 is arranged at the position corresponding to the second settling zone 30; a fourth liquid outlet 234 is arranged at a position corresponding to the second clarification zone 40, and a fifth liquid outlet 235 is arranged at a position corresponding to the third clarification zone 50. The first liquid outlet 231, the second liquid outlet 232 and the third liquid outlet 233 are all disposed at the bottom of the sidewall 23.

The pipeline 3 comprises a first pipeline 31 communicated with the first liquid outlet 231 and the catalyst regeneration device 4, a second pipeline 32 communicated with the second liquid outlet 232 and the catalytic treatment device 1, a third pipeline 33 communicated with the second liquid outlet 232 and the catalyst regeneration device 4, a fourth pipeline 34 communicated with the third liquid outlet 233 and the catalytic treatment device 1, a fifth pipeline 35 communicated with the fourth liquid outlet 234 and the catalytic treatment device 1, and a sixth pipeline 36 communicated with the fifth liquid outlet 235 and the catalyst regeneration device 4.

The first pipeline 31 is used for conveying the contaminated catalyst in the first precipitation zone 10 to the catalyst regeneration device 4 for secondary purification of exhaust gas and cyclic regeneration; the second pipeline 32 is used for conveying the clear liquid in the first clarification zone 20 to the catalytic treatment device 1 and a catalyst forming treatment liquid, the third line 33 is used to deliver the clean liquid in the first clarification zone 20 to the catalyst regeneration unit 4 to rinse the regenerated catalyst, the fourth line 34 is used for re-conveying the catalyst in the second settling zone 30 to the catalytic treatment unit 1, the fifth pipeline 35 is used for conveying the clear liquid in the second clarification zone 40 to the catalytic treatment device 1 and the catalyst forming treatment liquid as a supplement when the clear liquid in the first clarification zone 20 is insufficient, the sixth line 36 is used to deliver the clean liquid in the third clarification zone 50 to the catalyst regeneration unit 4 to rinse the regenerated catalyst as a supplement to the lack of clean liquid in the first clarification zone 20. It will be appreciated that the second line 32, the fourth line 34 and the fifth line 35 are connected to the first nozzle 12.

It should be noted that, corresponding still need be equipped with valve, pump body or other supporting subassembly on first pipeline 31, second pipeline 32, third pipeline 33, fourth pipeline 34, fifth pipeline 35 and the sixth pipeline 36, it selects the conventional means in this field can, the utility model discloses do not describe to this redundantly.

The catalyst regeneration device 4 can perform secondary treatment on the exhaust gas, and can also perform treatment on the polluted catalyst to recover the activity of the polluted catalyst, so that the cyclic utilization of the catalyst is realized. Specifically, the catalyst regeneration device 4 includes a second casing 41, a defogging layer 42 housed in the second casing 41, a second nozzle 43, a filler layer 44, a mechanical baffle 45, and a microwave device 46 annularly disposed around the filler layer 44, where the defogging layer 42, the second nozzle 43, the filler layer 44, and the mechanical baffle 45 are sequentially disposed at intervals from top to bottom.

The second casing 41 is a hollow cylindrical structure, the top of which is provided with an air outlet 411, the treated clean air is discharged from the air outlet 411, and the bottom of which is provided with a second opening 412 communicated with the sedimentation device 2.

The defogging layer 42 is used for absorbing moisture or fine particulate matters in the clean gas, and may further ensure the cleanliness of the exhaust gas, and specifically, the defogging layer 32 is disposed at one end of the second housing 41 close to the air outlet 411 and fixed on the inner wall of the second housing 41.

The second nozzle 43 is connected with the first pipeline 31, the third pipeline 33 and the sixth pipeline 36, valves for controlling the pipeline to be conducted and closed are respectively arranged on the first pipeline 31, the third pipeline 33 and the sixth pipeline 36, when the first pipeline 31 is conducted, the second nozzle 43 sprays slurry-shaped polluted catalyst on the packing layer 44, after the catalyst on the packing layer 44 reaches a certain thickness, the first pipeline 31 is closed, after the catalytic regeneration of the polluted catalyst is completed, the third pipeline 33 is opened, the second nozzle 43 sprays clear liquid to wash the catalyst and drop the catalyst to the second settling zone 30, if the clear liquid in the first settling zone 20 is insufficient, the sixth pipeline 36 is opened, and the clear liquid in the third settling zone 50 is conveyed to the second nozzle 43 to carry out spraying and washing on the catalyst. The second nozzles 43 are arranged in a direction opposite to the direction of movement of the gas flow, i.e. the second nozzles 43 are arranged in a direction towards the settling device 2.

The packing layer 44 is used for supporting the contaminated catalyst and providing a reaction site for the regeneration of the contaminated catalyst, and specifically, the packing layer 44 is made of a loose material and can allow liquid to pass through, so as to leave the contaminated catalyst. The packing layer 44 is provided in a plurality, and the packing layers 44 are spaced from each other, so that the probability of the contaminated catalyst adhering to the packing layer can be increased.

The microwave device 46 is fixedly connected to the second housing 41, and is configured to perform microwave treatment on the contaminated catalyst attached to the packing layer 44 to recover the activity of the catalyst. Further, the thickness of the packing layer 44 is matched with the microwave frequency band of the microwave device 46, and the thickness of the packing layer 44 is set to a thickness through which microwaves can penetrate.

The microwave devices 46 include a waveguide 461 connected to the filler layer 44 and microwave sources 462 connected to the waveguide 461, the waveguide 461 is sandwiched between the second housing 41 and the filler layer 44, and the microwave sources 462 are fixed to the outer wall of the second housing 41, it can be understood that the number of the microwave devices 46 corresponds to the number of the filler layers 44, that is, one filler layer corresponds to one microwave device 46.

The mechanical baffle 45 is arranged at one end of the second shell 41 close to the settling device 2, the catalyst subjected to microwave regeneration is washed by the clear liquid sprayed by the second nozzle 43 and falls onto the mechanical baffle 45, after a certain amount of the catalyst is accumulated, the mechanical baffle 45 is opened, the catalyst falls into the second settling zone 30 for settling, after the liquid level in the second settling zone 30 rises, the clear liquid on the upper layer of the second settling zone 30 can also flow over the partition plate 24 and the second partition plate 26 to enter the first settling zone 20 and the third settling zone 50 respectively. Mechanical baffle 45 still includes rather than assorted induction mechanism, control mechanism and actuating mechanism, it adopt in this field conventional technical means can, the utility model discloses do not describe to this repeatedly.

The first opening 112 is disposed opposite to the first settling zone 10, and the second opening 412 is disposed opposite to the second settling zone 30.

The first pipe 5 extends vertically from the first opening 112 toward the first settling area 10, and the end of the first pipe 5 is immersed in the liquid surface of the first settling area 10. The tail end of the first pipe body 5 is immersed in the liquid level of the first settling zone 10, so that the waste gas can be contacted and reacted with the catalyst again in the liquid, and the degradation effect is enhanced.

The second pipe 6 extends vertically from the second opening 412 toward the second settling zone 30, and the end of the second pipe 6 is exposed to the liquid surface of the second settling zone 30. The gas discharged into the liquid surface of the first settling zone 10 gradually rises to the liquid surface and enters the catalyst regeneration device 4 through the second pipe body 6.

Further, the first partition 25 includes a first body 251 fixed perpendicularly to the bottom wall 22, and a first extending portion 252 extending obliquely from an end of the first body 251 away from the bottom wall 22 to a direction approaching the bottom wall 22 and located below the first tube 5. The first extension part 252 can be used for guiding the flow, and can buffer the falling speed of the treatment liquid, so as to prevent the treatment liquid from splashing around. Preferably, the orthographic projection of the first extension 252 towards the catalytic treatment device 1 falls at least partially into the mouth of the first pipe body 5. Preferably, the included angle between the first extending portion 252 and the first body 251 is 30-45 °.

The second partition 26 includes a second body portion 261 fixed perpendicularly to the bottom wall 22, and a second extending portion 262 extending obliquely from an end of the second body portion 261 away from the bottom wall 22 toward a direction close to the bottom wall 22 and located below the second tube 6. The second extension part 262 can be used for guiding the flow and buffering the falling speed of the treatment liquid, so as to prevent the treatment liquid from splashing around. Preferably, the orthographic projection of said second extension 262 towards said catalyst regeneration device 4 at least partially falls inside the mouth of said second tubular body 6. Preferably, an included angle between the second extending portion 262 and the second body portion 261 is 30-45 °.

The above embodiments of the present invention are only described, and it should be noted that, for those skilled in the art, modifications can be made without departing from the inventive concept, but these all fall into the protection scope of the present invention.

Claims

1. A VOC photocatalytic treatment system comprises a catalytic treatment device, a precipitation device and a catalyst regeneration device, wherein the catalytic treatment device and the catalyst regeneration device are arranged above the precipitation device and are mutually spaced, the precipitation device is divided into a first precipitation area positioned below the catalytic treatment device, a second precipitation area positioned below the catalyst regeneration device, a first clarification area positioned between the first precipitation area and the second precipitation area, a second clarification area positioned on one side of the first precipitation area far away from the first clarification area, and a third clarification area positioned on one side of the second precipitation area far away from the first clarification area, the heights of the second clarification area and the third clarification area are lower than that of the first clarification area, and the first precipitation area and the third clarification area are respectively connected with the catalyst regeneration device through pipelines, the first clarification zone is respectively connected with the catalytic treatment device and the catalyst regeneration device through pipelines, the second clarification zone and the second sedimentation zone are connected with the catalytic treatment device through pipelines, the bottom of the catalytic treatment device is provided with a first opening communicated with the sedimentation device, the first opening is just opposite to the first sedimentation zone, the bottom of the catalyst regeneration device is provided with a second opening communicated with the sedimentation device, the second opening is just opposite to the second sedimentation zone, and waste gas enters from the catalytic treatment device and is discharged from the catalyst regeneration device, and the VOC photocatalytic treatment system is characterized by further comprising a first pipe body vertically extending from the first opening towards the direction close to the first sedimentation zone and a second pipe body vertically extending from the second opening towards the direction close to the second sedimentation zone, the tail end of the first pipe body is immersed in the liquid surface of the first settling zone, and the tail end of the second pipe body is exposed out of the liquid surface of the second settling zone.

2. The photocatalytic VOC treatment system of claim 1, wherein said precipitation device comprises a top wall, a bottom wall disposed opposite to said top wall, side walls connecting said top wall and said bottom wall, two partition plates fixed to said bottom wall and spaced apart from each other, and a first partition plate and a second partition plate fixed to said bottom wall and spaced apart symmetrically on both sides of said two partition plates, the top wall, the bottom wall and the side wall are matched to form an accommodating space, the heights of the partition board, the first partition board and the second partition board are smaller than the height of the side wall, the first partition plate, the two partition plates and the second partition plate are matched to sequentially partition the accommodating space from left to right to form the second clarification zone, the first settling zone, the first clarification zone, the second settling zone and the third settling zone which are communicated with each other, and the catalytic treatment device and the catalyst regeneration device are arranged on the top wall.

3. The VOC photocatalytic treatment system according to claim 2, wherein the first partition plate includes a first body portion vertically fixed to the bottom wall and a first extending portion extending obliquely from an end of the first body portion remote from the bottom wall toward the bottom wall and located under the first pipe, and the second partition plate includes a second body portion vertically fixed to the bottom wall and a second extending portion extending obliquely from an end of the second body portion remote from the bottom wall toward the bottom wall and located under the second pipe.

4. The VOC photocatalytic treatment system of claim 3, wherein an orthographic projection of said first extension toward said catalytic treatment device at least partially falls within a mouth of said first tube, and an orthographic projection of said second extension toward said catalyst regeneration device at least partially falls within a mouth of said second tube.

5. The VOC photocatalytic treatment system of claim 3, wherein the included angle between the first extending portion and the first body portion is 30-45 °, and the included angle between the second extending portion and the second body portion is 30-45 °.

6. The photocatalytic VOC treatment system according to claim 2, wherein said sidewall has a first exit hole at a position corresponding to said first settling zone, a second liquid outlet hole is arranged at the position corresponding to the first clarification zone, a third liquid outlet hole is arranged at the position corresponding to the second sedimentation zone, a fourth liquid outlet hole is arranged at the position corresponding to the second clarification zone, a fifth liquid outlet hole is arranged at the position corresponding to the third clarification zone, the first liquid outlet hole, the second liquid outlet hole and the third liquid outlet hole are all arranged at the bottom of the side wall, the first liquid outlet and the fifth liquid outlet are respectively connected with the catalyst regeneration device through pipelines, the second liquid outlet is respectively connected with the catalytic treatment device and the catalyst regeneration device through pipelines, the third liquid outlet and the fourth liquid outlet are respectively connected with the catalytic treatment device through pipelines.

7. The photocatalytic VOC treatment system according to claim 6, wherein said catalytic treatment device comprises a first housing having an air inlet, a first nozzle housed in said first housing, and a catalytic light source spaced from said first nozzle, wherein exhaust gas enters from said air inlet, said first nozzle is communicated with said second, third and fourth liquid outlets through a pipe for spraying a treatment liquid, said treatment liquid comprising a catalyst.

8. The photocatalytic VOC treatment system according to claim 7 wherein the first nozzle is disposed in a direction opposite to the direction of gas movement and the catalyst is TiO₂。

9. The photocatalytic VOC treatment system according to claim 6 wherein said catalyst regeneration device comprises a second housing having an air outlet, a second nozzle housed in said second housing, a packing layer disposed under said second nozzle, a microwave device disposed around said packing layer, a defogging layer secured to one end of said second housing near said air outlet, and a mechanical baffle secured to one end of said second housing near said precipitation device, said second nozzle and said packing layer being disposed between said defogging layer and said mechanical baffle, wherein said treated air is exhausted from said air outlet, said second nozzle is in communication with said first outlet via a conduit, and said second nozzle is oriented in a direction opposite to the direction of movement of the air.