CN115254424A

CN115254424A - Tail gas treatment system that high efficiency was removed dust

Info

Publication number: CN115254424A
Application number: CN202210899625.0A
Authority: CN
Inventors: 王福清
Original assignee: Shanghai Xie Micro Environment Technology Co ltd
Current assignee: Shanghai Xie Micro Environment Technology Co ltd
Priority date: 2022-07-28
Filing date: 2022-07-28
Publication date: 2022-11-01
Anticipated expiration: 2042-07-28
Also published as: CN115254424B

Abstract

The invention discloses a tail gas treatment system for efficient dust removal, belongs to the technical field of semiconductor harmful gas treatment, and solves the problems that a spray tower cannot collect dust particles with small particle sizes in the prior art, a subsequent air outlet pipe is easily blocked, and the dust particles which are not collected are easily discharged to the atmospheric environment to cause environmental pollution. The tail gas treatment system comprises a combustion reactor, a water tank, a spray tower, an electrified dust collector and an air outlet pipe which are sequentially connected along the flow direction of tail gas; the electrified dust collector comprises an anode precipitation cylinder and a cathode arranged in the anode precipitation cylinder, the anode precipitation cylinder is connected with the gas outlet of the spray tower, the cathode is connected with the power supply unit, and the anode precipitation cylinder is grounded. The tail gas treatment system with high-efficiency dust removal can be used for treating tail gas generated by a generic semiconductor processing technology.

Description

Tail gas treatment system that high efficiency was removed dust

Technical Field

The invention belongs to the technical field of semiconductor harmful gas treatment, and particularly relates to a tail gas treatment system for efficient dust removal.

Background

In the prior art, dust particles in tail gas are usually captured by adopting a spray tower, but the spray tower can only capture dust particles with larger particle size, and the dust particles with smaller particle size which are not captured by the spray tower are directly discharged to an air outlet pipe along with the tail gas, so that the air outlet pipe is easily blocked.

In addition, the dust particles which are not captured are discharged to the atmosphere through the air outlet pipe, so that environmental pollution is caused.

Disclosure of Invention

In view of the above analysis, the present invention aims to provide an efficient dust removal tail gas treatment system, which solves the problems that a spray tower in the prior art cannot collect dust particles with small particle sizes, so that the subsequent air outlet pipe is easily blocked, and the dust particles which are not collected are discharged to the atmospheric environment, so as to cause environmental pollution.

The invention is mainly realized by the following technical scheme:

the invention provides a tail gas treatment system for efficient dust removal, which comprises a combustion reactor, a water tank, a spray tower, an electrified dust remover and an air outlet pipe, wherein the combustion reactor, the water tank, the spray tower, the electrified dust remover and the air outlet pipe are sequentially connected along the flow direction of tail gas; the electrified dust collector comprises an anode precipitation cylinder and a cathode arranged in the anode precipitation cylinder, the anode precipitation cylinder is connected with the gas outlet of the spray tower, the cathode is connected with the power supply unit, and the anode precipitation cylinder is grounded.

Furthermore, the combustion reactor and the spray tower are both arranged above the water tank, and the electrified dust collector is arranged above the spray tower.

Further, the combustion reactor comprises a thermal decomposition cavity, a reaction cavity and a heating unit, wherein the thermal decomposition cavity is located above the reaction cavity and is communicated with the reaction cavity through a fluid rotating flange without an overlapping area, a liquid outlet of the fluid rotating flange is communicated with the reaction cavity, and the fluid rotating flange is used for forming a spiral water film flowing spirally on the inner wall of the reaction cavity and driving tail gas in the reaction cavity to rotate.

Furthermore, the water tank comprises a tank body, an anti-corrosion layer arranged on the inner wall of the tank body and a water pump arranged above the tank body, and liquid in the tank body is supplied into the spray tower and the fluid rotating flange through the water pump.

Further, the spray tower comprises a spray box, an anticorrosive layer arranged on the inner wall of the spray box, and a packing layer, a spray nozzle and a multi-mesh material layer which are arranged in the spray box;

the packing layer, the spraying nozzle and the multi-mesh material layer are sequentially arranged along the direction from the air inlet to the air outlet of the spraying box.

Furthermore, one end of the anode precipitation cylinder, which is far away from the spray tower, is provided with a wall cleaning nozzle.

Further, the spray tower is connected with the anode precipitation cylinder through a buffer tube.

Further, the section area of the buffer tube is gradually increased along the direction from the spray tower to the anode precipitation cylinder.

Furthermore, one end of the buffer tube, which is close to the spray tower, is provided with a plurality of flow equalizing plates along the axial direction, flow equalizing holes are formed in the flow equalizing plates, and the flow equalizing holes in two adjacent flow equalizing plates are arranged in a staggered manner.

Furthermore, the tail gas treatment system is suitable for collecting dust particles with the particle size of 0.1-100 mu m.

Compared with the prior art, the invention can realize at least one of the following beneficial effects:

according to the efficient dust removal tail gas treatment system, the electrified dust remover is arranged in the follow-up of the spray tower, high-voltage current provided by the power supply unit is introduced into the cathode in the electrified dust remover, an unbalanced electric field is generated between the electrified dust remover and the grounded anode precipitation cylinder, corona discharge is generated by the unbalanced electric field to ionize gas between the cathode and the anode precipitation cylinder, electrons in the gas move towards the anode precipitation cylinder and collide with dust particles to enable the dust particles to carry the electrons and to be negatively electrified, the negatively electrified dust particles continue to move towards the anode precipitation cylinder under the action of the electric field and are emitted after reaching the anode precipitation cylinder, and the dust particles are deposited on the anode precipitation cylinder, so that the capture of tiny dust particles is realized, and the problems of environment pollution caused by the blockage of a follow-up air outlet pipe and the discharge of tail gas with the dust particles into the environment are effectively solved.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and drawings.

Drawings

The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the invention, wherein like reference numerals are used to designate like parts throughout.

FIG. 1 is a schematic structural diagram of a high-efficiency dedusting tail gas treatment system according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a combustion reactor in an efficient dedusting exhaust gas treatment system according to an embodiment of the present invention;

FIG. 3 is a schematic view of a portion of a combustion reactor in an efficient dedusting exhaust treatment system according to an embodiment of the present invention;

FIG. 4 is a schematic diagram illustrating a connection between an air inlet assembly and a combustion reactor in an exhaust gas treatment system with high dust removal efficiency according to an embodiment of the present invention;

fig. 5 is a schematic structural diagram of a reaction chamber in the exhaust gas treatment system with high dust removal efficiency according to an embodiment of the present invention;

fig. 6 is a schematic structural diagram of a spray tower in the high-efficiency dust removal tail gas treatment system according to the first embodiment of the present invention;

fig. 7 is a schematic structural diagram of a fluid rotating flange in the exhaust gas treatment system with high-efficiency dust removal according to an embodiment of the present invention;

FIG. 8 is a top view of a fluid rotating flange in an exemplary embodiment of a high efficiency dust removal exhaust treatment system;

fig. 9 is a schematic structural diagram of a belt electric precipitator in the high-efficiency dust removal tail gas treatment system according to the first embodiment of the present invention;

fig. 10 is a schematic view of a connection structure between a belt electric dust collector and a buffer tube in the high-efficiency dust-removing tail gas treatment system according to an embodiment of the present invention;

fig. 11 is a schematic diagram illustrating an arrangement of an anode precipitation cylinder in the high-efficiency dust-removal tail gas treatment system according to an embodiment of the present invention;

fig. 12 is a schematic view of another arrangement of the anode precipitation cylinder in the high-efficiency dust-removing exhaust gas treatment system according to the first embodiment of the present invention.

Reference numerals are as follows:

1-a thermal decomposition chamber; 2-a reaction chamber; 3-a heating unit; 31-a flame generator; 32-liquid cooling liquid inlet pipe; 33-liquid cooling drain pipe; 4-a reaction gas supply unit; 5-a fluid rotating flange; 51-flange base; 52-an overflow launder; 53-overflow branch; 6-a water tank; 7-a handle; 8-an air intake assembly; 81-air inlet pipe; 82-a purge tube; 83-a connector; 84-a first elbow pipe; 85-a second elbow pipe; 86-third elbow pipe; 87-a stationary tube; 9-water level observation pipe; 10-a spray tower; 101-a spray box; 102-a filler layer; 103-a spray nozzle; 104-a multi-mesh material layer; 105-a backwash nozzle; 11-an air outlet pipe; 12-an electrified dust collector; 121-anode precipitation cylinder; 122-a cathode; 123-wall cleaning nozzle; 124-a dust removal shell; 125-observation window; 13-a buffer tube; 14-flow equalization plate.

Detailed Description

The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form a part hereof, and which together with the embodiments of the invention serve to explain the principles of the invention.

Example one

The embodiment provides a tail gas treatment system with high-efficiency dust removal, see fig. 1 to 12, which includes a combustion reactor, a water tank 6, a spray tower 10, an electrified dust remover 12 and an air outlet pipe 11, which are sequentially connected along the tail gas flowing direction, wherein the electrified dust remover 12 includes an anode precipitation cylinder 121 and a cathode 122 with spurs arranged in the anode precipitation cylinder 121, the anode precipitation cylinder 121 is connected with an air outlet of the spray tower, the cathode 122 is connected with a power supply unit (for example, a high-voltage power supply unit, the voltage provided by the high-voltage power supply unit can reach tens of thousands of volts), and the anode precipitation cylinder 121 is grounded.

In spatial position, illustratively, the combustion reactor and the spray tower 10 are both mounted above the water tank 6, and the charged dust collector 12 is provided above the spray tower 10.

In implementation, the power supply unit is turned on, high-voltage current provided by the power supply unit is introduced into the cathode 122, an unbalanced electric field is generated between the power supply unit and the grounded anode precipitation cylinder 121, corona discharge is generated by the unbalanced electric field to ionize gas between the cathode 122 and the anode precipitation cylinder 121, electrons in the gas move towards the anode precipitation cylinder 121, the dust particles are collided with the dust particles to carry the electrons and are negatively charged, the negatively charged dust particles continue to move towards the anode precipitation cylinder 121 under the action of the electric field, the electrons are emitted after reaching the anode precipitation cylinder 121, and the dust particles are deposited on the anode precipitation cylinder 121, so that the tiny dust particles are collected.

Compared with the prior art, the efficient dedusting tail gas treatment system provided by the embodiment is characterized in that the charged dust collector 12 is arranged in the spray tower in the follow-up manner, in the charged dust collector 12, high-voltage current provided by the power supply unit is introduced into the cathode 122, an unbalanced electric field is generated between the charged dust collector 12 and the grounded anode precipitation cylinder 121, the unbalanced electric field generates corona discharge to ionize gas between the cathode 122 and the anode precipitation cylinder 121, electrons in the gas move towards the anode precipitation cylinder 121 and collide with dust particles to enable the dust particles to carry the electrons and to be negatively charged, the negatively charged dust particles continue to move towards the anode precipitation cylinder 121 under the action of the electric field, the electrons are emitted after reaching the anode precipitation cylinder 121, and the dust particles are deposited on the anode precipitation cylinder 121, so that the capture of tiny dust particles is realized, and the problems that the follow-up air outlet pipe 11 is blocked and tail gas with the dust particles is discharged into the environment to cause environmental pollution are effectively solved.

It should be noted that the exhaust gas treatment system with high dust removal efficiency of the embodiment is particularly suitable for a process with a large amount of dust particles, for example, a large amount of SiO may be generated in a CVD process in the photovoltaic industry₂The system can collect fine dust particles having a particle size range of 0.1 to 100 μm, particularly fine dust particles having a particle size of 10 μm or less.

It is worth noting that the dust particles will be deposited on the inner wall of the anode precipitation cylinder 121 continuously, in order to clean the inner wall of the anode precipitation cylinder 121 regularly, a wall cleaning nozzle 123 is disposed at one end of the anode precipitation cylinder 121 far away from the spray tower 10, when a large amount of dust particles on the inner wall of the anode precipitation cylinder 121 are accumulated, the back washing function can be started in a short time, and the liquid sprayed from the wall cleaning nozzle 123 can wash the inner wall of the anode precipitation cylinder 121, so that the dust particles on the inner wall of the anode precipitation cylinder 121 are flushed back to the spray tower 10 and further flow into the water tank 6.

Considering that the flow velocity of the tail gas in the anode precipitation cylinder 121 directly affects the dust particle collection efficiency, the lower the tail gas flow velocity, the higher the collection efficiency, therefore, the spray tower 10 is connected with the anode precipitation cylinder 121 through the buffer tube 13, and the cross-sectional area of the buffer tube 13 gradually increases along the direction from the spray tower 10 to the anode precipitation cylinder 121. Like this, under the unchangeable condition of gas outlet department pressure of spray column 10, along with the increase of the cross sectional area of buffer tube 13, the velocity of flow of tail gas can reduce gradually to can guarantee the abundant entrapment of dust granule in an anode precipitation section of thick bamboo 121, improve the entrapment efficiency.

In order to further reduce the flow rate of the tail gas, a plurality of flow equalizing plates 14 are axially arranged at one end of the buffer tube 13 close to the spray tower 10, flow equalizing holes are formed in the flow equalizing plates 14, and the flow equalizing holes in two adjacent flow equalizing plates 14 are arranged in a staggered manner, that is, the axes of the flow equalizing holes in two adjacent flow equalizing plates 14 are not coincident. Like this, through the hole of flow equalizing of staggered arrangement, can effectively prolong the flow path of tail gas, can also increase the flow resistance of tail gas simultaneously to can further reduce tail gas flow velocity.

Likewise, in addition to reducing the flow rate of the exhaust gas, the capturing efficiency may also be improved by increasing the number of the cathodes 122 and the anode precipitation cylinders 121, for example, the number of the cathodes 122 and the anode precipitation cylinders 121 is plural, and the number corresponds to one.

In order to effectively simplify the overall structure, the number of the buffer tubes 13 is one, and one buffer tube 13 corresponds to a plurality of anode precipitation cylinders 121, that is, the plurality of anode precipitation cylinders 121 are communicated with the air outlet of the spray tower through one buffer tube 13.

In order to increase the number of the anode precipitation cylinders 121 arranged in a certain volume as much as possible, the cross-sectional shape of the anode precipitation cylinder 121 may be, for example, a circle, and the anode precipitation cylinder 121 is divided into a central anode precipitation cylinder disposed in the center and a peripheral anode precipitation cylinder surrounding the central anode precipitation cylinder; or, the cross-sectional shape of the anode precipitation cylinder 121 may be regular hexagon, two adjacent anode precipitation cylinders 121 share the same side wall, and the plurality of anode precipitation cylinders 121 are arranged in a honeycomb shape, and with the anode precipitation cylinders 121 having such a shape, on one hand, there is no gap between two adjacent anode precipitation cylinders 121, so that the arrangement number of the anode precipitation cylinders 121 can be increased to the maximum, and on the other hand, because two adjacent anode precipitation cylinders 121 share the same side wall, the amount of material used by the anode precipitation cylinders 121 can be effectively reduced.

It is understood that, in order to protect the anode precipitation cylinder 121 and improve the integrity of the charged dust collector 12, the charged dust collector 12 further includes a dust collecting housing 124, and the anode precipitation cylinder 121 is disposed in the dust collecting housing 124.

In order to enable an operator to know the dust particle trapping amount in the anode precipitation cylinder 121 in real time, the dust removing housing 124 is provided with an observation window 125, the observation window 125 is made of a transparent material, and the operator can know the dust particle trapping amount in the anode precipitation cylinder 121 in real time through the observation window 125.

For the structure of the combustion reactor, specifically, the combustion reactor includes a thermal decomposition chamber 1, a reaction chamber 2, a heating unit 3, and a reactant gas supply unit 4, the thermal decomposition chamber 1 is located above the reaction chamber 2, the two are communicated through a fluid rotating flange 5 and do not have an overlapping region, a liquid outlet of the fluid rotating flange 5 is communicated with the reaction chamber 2, the fluid rotating flange 5 is used for forming a spiral water film flowing spirally on an inner wall of the reaction chamber 2 and driving tail gas in the reaction chamber 2 to rotate, illustratively, the reactant gas is one or a mixture of two or more of air, oxygen, hydrogen, and ammonia, the heating unit 3 is used for providing heat for the thermal decomposition chamber 1, and an air outlet of the reactant gas supply unit 4 is located on a side wall of the thermal decomposition chamber 1 near one end of the fluid rotating flange 5. It should be noted that the spiral water film means that the water flow has a certain tangential velocity, so that the water film can be in a spiral rotation state on the inner wall of the reaction chamber 2.

When the method is implemented, tail gas generated in the pan-semiconductor production process enters the thermal decomposition cavity 1, and in the thermal decomposition cavity 1, the tail gas is heated to be more than 1400 ℃ under the heating of the heating unit 3, so that part of harmful gas is thermally decomposed; when the tail gas which is not subjected to thermal decomposition passes through the gas outlet of the reaction gas supply unit 4, the tail gas is in contact with the reaction gas and is fully mixed with the reaction gas, and the reaction gas is driven to enter the reaction cavity 2 together for oxidation or reduction reaction, so that part of the tail gas which is not subjected to thermal decomposition is further converted into dust particles or gas which is easily dissolved in water; dust particles and water-soluble gas interact with a water film on the inner wall of the reaction cavity 2, the dust particles and the water-soluble gas are taken away from the reaction cavity 2 by the water film and flow into the water tank 6, tail gas after reaction in the reaction cavity 2 further flows into the spray tower 10 along the space above the liquid level of the water tank, and the spray tower 10 realizes the treatment of the tail gas generated in the conventional semiconductor production process.

The combustion reactor adopting the structure has the following beneficial effects:

because the existence of spiral water film, under the high temperature environment of reaction chamber 2, a large amount of heats can be taken away in the gasification of water, can protect the reaction chamber for a long time not receive the damage for the hydrogen of maximum flow to 150slm can be handled to the reaction chamber, and the hydrogen of 50slm is handled to conventional equipment intelligence the biggest. Meanwhile, as the heat exchange efficiency of the spiral water curtain is far greater than that of the existing jacket heat exchange type reaction cavity, the higher heat exchange efficiency can treat more harmful gases or the same harmful gases under the condition of the same reaction cavity volume, thereby greatly reducing required equipment.

Thermal decomposition chamber 1 and reaction chamber 2 communicate through fluid rotary flange 5 and do not have the overlap region, can guarantee that the reaction of harmful gas and reaction gas all goes on in reaction chamber 2, and can not go on in thermal decomposition chamber 1, thereby can avoid generating dust granule and corrosive gas in thermal decomposition chamber 1, the life and the maintenance cycle of extension thermal decomposition chamber 1, it needs to explain, thermal decomposition chamber 1's main function is heating tail gas and the partial harmful gas of thermal decomposition, its structure is comparatively complicated (has partial dead zone and dog-ear etc.), be difficult to accomplish complete corrosion protection, dust granule and corrosive gas can cause serious corruption to thermal decomposition chamber 1 in thermal decomposition chamber 1.

In order to realize thermal decomposition, the temperature in the thermal decomposition cavity 1 can reach more than 1400 ℃, and the thermal decomposition cavity 1 and the reaction cavity 2 are independently arranged, so that on one hand, a spiral water film is arranged in the reaction cavity 2, most of heat can be taken away by the spiral water film, the thermal decomposition cavity 1 and the reaction cavity 2 are independently arranged, and the influence of the spiral water film on the temperature of the thermal decomposition cavity 1 can be avoided; on the other hand, it is possible to ensure that the harmful gas is thermally decomposed without oxidation/reduction reaction, and to avoid the formation of by-products (e.g., nitrogen oxides: NO, NO)₂Etc.), it is noted that the bottom gas is nitrogen except harmful gas in the tail gas, and the temperature of the nitrogen and the oxygen is above 1000 DEG CA large amount of nitrogen oxides, which are also one of the atmospheric pollutants, are generated in the environment, and cannot be treated by the spray tower 10, and environmental pollution is caused after the nitrogen oxides are discharged.

Harmful gases can generate dust particles and water-soluble gases in the reaction chamber 2, wherein the dust particles can gradually accumulate in the reaction chamber 2 to block the reaction chamber 2 if not cleaned in time. Through the arrangement of the fluid rotating flange 5, water flow with tangential component velocity can flow spirally on the inner wall of the reaction cavity 2 after meeting the inner wall of the reaction cavity 2, covers the whole inner wall of the reaction cavity 2 and has the characteristic of spiral flow, so that the coverage uniformity of a spiral water film can be improved, the problem of uneven distribution of the water film formed in a natural overflow mode is effectively solved, the corrosion of corrosive gas generated by tail gas on the side wall of the reaction cavity 2 is avoided, and the service life of the reaction cavity 2 is effectively prolonged; the spiral water film can further drive the tail gas in the reaction cavity 2 to rotate, the retention time of the tail gas in the reaction cavity 2 is prolonged, dust particles and water-soluble gas can contact and mix with the tail gas which flows in a rotating manner and the water film, and the dust particles and the water-soluble gas are trapped by the water film and flow into the subsequent water tank 6, so that the dust particles can be prevented from blocking the reaction cavity 2; because pyrolysis chamber 1 and reaction chamber 2 intercommunication, heating element 3 has certain heating effect to the spiral water film equally, the spiral water film after being heated can further promote high temperature tail gas and external heat and mass rate through flowing, in addition, because the spiral water film has certain tangential velocity, the flow path length of water film at 2 lateral walls of reaction chamber has been prolonged in other words, high temperature tail gas and external heat and mass rate also can be strengthened, further avoid reaction chamber 2 because of the damage that high temperature produced, the life of extension reaction chamber 2.

In practical applications, the high-efficiency dust-removing tail gas treatment system of the embodiment can be used for the types of tail gas generated by the semi-conductor processing technology, and is shown in table 1:

TABLE 1 types of exhaust gases generated by the generic semiconductor process

Process for the preparation of a coating	Produced tail gas
		Cleaning of	Cl₂、ClF₃、NF₃、C₂H₆、SF₆HCl, etc
Deposition of	NH₃、N₂O、TEOS、SiH₄、NO、WF₆Etc. of
		Lithography	Ar、F₂Ne, kr, he, etc
Etching of	NF₃、C₄F₈、COS、CF₄、C₂F₆、HF、CH₃F、SiF₄、SF₆、BCl₃Etc. of
		Ion implantation	BF₃、B₂H₆、AsH₃、TEB、TEPO、PH₃Etc. of
Epitaxy	HCl、SiH₂Cl₂、SiHCl₃、H₂Etc. of

The total flow of the tail gas which can be treated by the system is 200-3000L/min, the removal efficiency of harmful gas can reach more than 99% by adopting the tail gas treatment system for high-efficiency dust removal, and the treated gas can be directly discharged to the atmospheric environment.

For the function of the water tank 6, which is specifically both the reaction chamber and the base of the spray tower 10, and is also capable of storing circulating spray water, the water tank 6 contains a liquid (including but not limited to sodium hydroxide, sodium carbonate, sodium bicarbonate, potassium hydroxide, etc.) for providing liquid to the spray tower 10 and the spiral water film.

As for the structure of the water tank 6, specifically, it may include a tank body, a corrosion prevention layer provided on an inner wall of the tank body, and a water pump provided above the tank body, through which liquid in the tank body is supplied into the spray tower 10 and the fluid rotary flange 5, and illustratively, the material of the tank body may be a stainless steel material or an engineering plastic (e.g., an engineering PP material), and the corrosion prevention layer may be a teflon layer.

In order to facilitate an operator to know the temperature of liquid in the water tank in real time, a plurality of temperature sensors for detecting the temperature of the liquid in the tank body are arranged in the tank body, once the temperature of the liquid exceeds a threshold value, the gas cooling effect is relatively poor, early warning can be given out, the spraying flow is adjusted through PLC program feedback, the fresh water flow in the tank body is adjusted, and the effects of energy conservation and water conservation are achieved.

As for the structure of the spray tower 10, specifically, the spray tower comprises a spray box 101, an anticorrosive layer arranged on the inner wall of the spray box 101, a packing layer 102, spray nozzles 103 and a multi-mesh material layer 104 arranged in the spray box 101, wherein the number of the spray nozzles 103 is multiple, the gas outlet of the water tank is connected with the gas inlet of the spray box 101 through an upper flange, the gas outlet of the spray box 101 is communicated with an anode precipitation cylinder 121 through an upper flange, and the packing layer 102, the spray nozzles 103 and the multi-mesh material layer 104 are sequentially arranged along the direction from the gas inlet to the gas outlet of the spray box 101, so that on one hand, dust particles in tail gas can be removed through the packing layer 102, and gas which is easy to dissolve in water can be absorbed through the spray nozzles 103; on the other hand, as the tail gas contains a large amount of water vapor and part of fine dust particles (< 10 μm) after being sprayed, the water vapor and the dust particles are discharged to a subsequent pipeline to cause liquid accumulation, blockage and corrosion, and the removal operation is needed, the multi-mesh material layer 104 is a multi-mesh material which is woven by corrosion-resistant high-strength filiform materials (such as engineering PP, polytetrafluoroethylene, fluorinated ethylene propylene, chlorine partial resin and the like) to form a filiform net, and when the liquid drops and the dust particles pass through the multi-mesh material layer, the small liquid drops are converged and flow back to the spraying tower 10 and the water tank 6 as large liquid drops; fine dust particles are trapped within the mesh material.

Illustratively, the material of the spray box 101 may be a stainless steel material or an engineering plastic (e.g., an engineering PP material), and the corrosion-resistant layer may be a teflon layer.

In order to properly clean the inner wall of the spray box 101 (i.e., the inner wall of the anticorrosive coating) and reduce the accumulation of dust particles, a back-flush nozzle 105 is provided at the upper portion of the spray box 101, and the dust particles are flushed and returned to the spray tower 10 and the water tank 6 by water flow.

In order to form a water film flowing spirally, the fluid rotating flange 5 has the following structure: the water supply device comprises a flange base body 51, an overflow groove 52 and overflow branch pipes 53, wherein the overflow groove 52 and the overflow branch pipes 53 are arranged on the flange base body 51, the water supply unit is communicated with the overflow groove 52 through the overflow branch pipes 53, the included angle between the liquid inlet of each overflow branch pipe 53 and the tangential direction of the side wall of the overflow groove 52 is alpha, and alpha is more than 0 degree and less than 90 degrees. In operation, water flow enters the overflow groove 52 through the overflow branch 53, and the water flow guided by the overflow branch 53 enters the overflow groove 52 to form a rotating water flow which gradually rises and overflows from the overflow groove 52 into the reaction chamber 2 to form a spiral water film completely covering the inner wall of the reaction chamber 2.

Illustratively, the number of the overflow branch pipes 53 is 2-8, 2-8 overflow branch pipes 53 are uniformly arranged along the axial direction of the overflow groove 52, alpha is more than or equal to 30 degrees and less than or equal to 75 degrees, the water flow speed in the overflow branch pipes 53 is 10-100L/min, and the water flow temperature is 15-30 ℃.

Considering that the liquid inlet angle and the water flow of the overflow branch pipe 53 affect whether the water film can completely cover the side wall of the reaction chamber 2, the liquid inlet angle and the water flow speed need to be determined according to parameters such as tail gas composition, tail gas flow and water pressure, firstly, the tail gas composition (especially the gas proportion of the dust particles generated by monosilane and the like) and the tail gas flow affect the generation amount of the dust particles, and exemplarily, according to the actual situation, the flow of monosilane is divided into low flow (less than 0.5L/min), medium flow (0.5-1.2L/min) and high flow (more than 1.2L/min); secondly, the water pressure affects the inflow of water and the form of a water film, and is classified into a low water pressure (0.4 to 0.6 Mpa) and a normal water pressure (0.6 to 1.0 Mpa) according to actual conditions.

In the practical application process, parameters are adjusted according to actual conditions and experimental data on site to achieve complete coverage of the water film on the inner wall surface, and specific parameters are shown in table 2.

TABLE 2 relationship between silane flow, water pressure, feed Angle, number and Water flow

Illustratively, preferred ranges or preferred values for the above specific parameters are found in table 3.

TABLE 3 preferred ranges for silane flow, water pressure, feed Angle, number and Water flow

Flow rate of monosilane	Water pressure	Angle/degree of feed liquid	Number of overflow ports	Water flow (L/min)
					Low flow rate	Low water pressure	35 to 40 (e.g., 45)	2～3	7
Middle flow rate	Low water pressure	40 to 45 (e.g., 45)	3～4	4
					High flow rate	Low water pressure	45 to 50 (e.g., 50)	4～6	6
Low flow rate	Normal water pressure	50-55 (e.g., 50)	4～5	5
					Middle flow rate	Normal water pressure	55 to 65 (e.g., 50)	5～6	5
High flow rate	Normal water pressure	65-70 (e.g., 52)	6～8	6

As for the structure of the reaction gas supply unit 4, specifically, it includes a plurality of reaction gas nozzles, the plurality of reaction gas nozzles are uniformly arranged along the axial direction of the thermal decomposition chamber 1, the compressed reaction gas provides the reaction gas to the end of the thermal decomposition chamber 1 close to the fluid rotating flange 5 through the plurality of reaction gas nozzles, and in the flowing process of the tail gas along the thermal decomposition chamber 1, the tail gas contacts with the reaction gas and is fully mixed, and drives the reaction gas to enter the reaction chamber 2 together for oxidation or reduction reaction, further converting the harmful gas which is not thermally decomposed into dust particles or gas which is easily dissolved in water.

In order to ensure the heating efficiency of the heating unit 3, the heating unit 3 exemplarily includes a flame generator 31 (for example, a gas flame generator 31 or a plasma flame generator 31 or other forms of flame generators 31) disposed at the top end of the thermal decomposition chamber 1, a torch head of the flame generator 31 is located in the thermal decomposition chamber 1, and a flame (which may also be a plasma flame) generated by the flame generator 31 extends at least into the thermal decomposition chamber 1, which may also extend through the thermal decomposition chamber 1 and into the reaction chamber 2 in an initial stage to initiate a reaction in the reaction chamber 2.

In order to further increase the temperature in the thermal decomposition chamber 1 and promote the thermal decomposition of the harmful gas, especially PFCs gas, the temperature of which needs to reach above 1400 ℃ to be able to perform the thermal decomposition or oxidation reaction, the flame generator 31 may be a plasma flame generator 31, because the temperature of the flame generated by the plasma flame generator 31 is high and can reach above 3000 ℃, so that the temperature in the thermal decomposition chamber 1 can be rapidly heated to above 2000 ℃ and far above 1400 ℃, thereby ensuring the thermal decomposition effect of the harmful gas.

Considering that the flame temperature generated by the flame generator 31 is high, in order to promote the heat dissipation of the flame generator 31, the heating unit 3 further comprises a liquid cooling loop, the liquid cooling loop comprises a liquid cooling cavity, and a liquid cooling liquid inlet pipe 32 and a liquid cooling liquid outlet pipe 33 which are positioned outside the liquid cooling cavity, the liquid cooling cavity is positioned on the outer wall of the flame generator 31, the liquid cooling liquid inlet pipe 32 and the liquid cooling liquid outlet pipe 33 are respectively communicated with the liquid cooling cavity, the three parts form the liquid cooling loop, and the cooling liquid (for example, cooling water with the temperature of 20-25 ℃) cools the side wall of the flame generator 31 among the liquid cooling liquid inlet pipe 32, the liquid cooling liquid outlet pipe 33 and the liquid cooling cavity. It should be noted that, for the liquid-cooling chamber, the outer shell of the flame generator 31 may be processed into a double-layer shell, and the cavity between the double-layer shell is used as the liquid-cooling chamber. Like this, through the setting of liquid cooling return circuit, can carry out effectual cooling to flame generator 31's shell, can avoid flame generator 31's the condition emergence that the high temperature caused the damage basically.

In order to further improve the corrosion resistance of the side wall of the reaction chamber 2, the inner wall of the reaction chamber 2 is provided with a corrosion-resistant layer (e.g., teflon layer), by which the corrosion resistance of the inner wall of the reaction chamber 2 can be effectively improved.

In order to further improve the high temperature resistance of the pyrolysis chamber 1, the inner wall of the pyrolysis chamber 1 is provided with a fireproof layer, and the pyrolysis chamber 1 can be effectively protected by the fireproof layer due to the high temperature resistance of the pyrolysis chamber 1.

In order to facilitate the installation and replacement of the reaction chamber 2, the side wall of the reaction chamber 2 is provided with a handle 7, and an operator can install and replace the reaction chamber 2 more conveniently by holding the handle 7.

It can be understood that, in order to convey the exhaust gas from the processing equipment of the semiconductor processing equipment into the thermal decomposition chamber 1, the above-mentioned exhaust gas treatment system for efficient dust removal further comprises a plurality of air inlet assemblies 8, the exhaust gas outlet of the processing equipment of the semiconductor processing equipment is connected with the air inlet of the thermal decomposition chamber 1 through the air inlet assemblies 8, for example, 4 to 6 air inlet assemblies 8 are provided, and the plurality of air inlet assemblies 8 are uniformly distributed along the axial direction of the thermal decomposition chamber 1.

To the structure of the air inlet component 8, particularly, the structure comprises an air inlet pipe 81, an elbow and a connecting piece 83 which are connected in sequence, wherein an air inlet of the air inlet pipe 81 is communicated with a tail gas outlet of processing equipment of a generic semiconductor, an air outlet of the air inlet pipe 81 is communicated with the elbow through the connecting piece 83, an air outlet of the elbow is communicated with the thermal decomposition cavity 1, and the tail gas is introduced into the thermal decomposition cavity 1 through the air inlet pipe 81 and the elbow in sequence.

The intake pipe 81 can be a stainless steel pipe, end flanges are arranged at both ends of the intake pipe, one end of the intake pipe 81 is communicated with a tail gas outlet of the processing equipment of the semi-conductor through one end flange, and the other end of the intake pipe 81 is communicated with the connecting piece 83 through the other end flange.

The connecting member 83 may be a corrugated stainless steel pipe or a straight stainless steel pipe with flanges at both ends thereof, and plays a role in connecting the air inlet pipe 81 and the elbow, wherein the connecting member 83 is preferably a corrugated stainless steel pipe, because the corrugated stainless steel pipe can eliminate radial and circumferential tolerances, is convenient to install, and can also avoid damage caused by stress.

Considering that dust particles may flow into the air inlet assembly 8 and deposit on the elbow, the air inlet assembly 8 further includes a purge pipe 82, the elbow is a three-way elbow and includes a first elbow pipe 84, a second elbow pipe 85 and a third elbow pipe 86 which are communicated with each other, wherein the first elbow pipe 84 is communicated with the air outlet of the air inlet pipe 81, the second elbow pipe 85 is communicated with the purge pipe 82, the air outlet end of the purge pipe 82 is provided with a purge nozzle, and the third elbow pipe 86 is communicated with the thermal decomposition chamber 1, so that, under the control of the purge pipe 82, when the exhaust gas treatment system for high efficiency dust removal is operated for a certain time (e.g., 1 hour), a part of the dust particles are accumulated at the elbow, at this time, the purge pipe 82 can be opened for a certain time (e.g., 2 seconds), nitrogen gas under a certain pressure is released into the elbow, the nitrogen gas is circulated and purged into the thermal reaction chamber, and the dust particles in the elbow are prevented from being blocked by the air flow and taken away by the air inlet assembly 8.

Illustratively, the included angle between the axis of the second elbow pipe 85 and the axis of the third elbow pipe 86 is β,90 ° < β ≦ 180 °, the included angle between the axis of the first elbow pipe 84 and the axis of the third elbow pipe 86 is γ, the purge gas of the purge pipe 82 is inert gas (e.g., nitrogen, etc.) and the purge flow rate is 10 to 100L/min, where γ is 0 ° < γ ≦ 90 °.

In order to know the pressure of the exhaust gas in the intake pipe 81 and the fluency of the elbow in real time, a pressure sensor is arranged on the side wall of the intake pipe 81. Like this, can know the air feed pressure in the intake pipe 81 in real time through pressure sensor, when the elbow appears blockking up, the corresponding rising of tail gas pressure meeting in the intake pipe 81 to can make the operator discover blocking phenomenon, in time open and sweep pipe 82.

For the installation of the pressure sensor, specifically, the side wall of the air inlet pipe 81 is provided with a fixed pipe 87, the pressure sensor is arranged in the fixed pipe 87, the probe of the pressure sensor extends into the air inlet pipe 81, the fixed pipe 87 is inclined downwards along the direction gradually approaching to the side wall of the air inlet pipe 81, and the included angle between the fixed pipe 87 and the axial direction of the air inlet pipe 81 is exemplarily 40-60 ° (for example, 45 °). Because the tail gas outlet of the processing equipment of the generic semiconductor is negative pressure, the fixed pipe 87 which is obliquely fixed can avoid the accumulation of dust particles to cause the reading deviation of the pressure sensor.

It is worth noting that, in the process of tail gas treatment, the inner wall of the reaction cavity 2 is always corroded by corrosive gas, the tightness of the reaction cavity 2 is crucial to the effect of tail gas treatment, and in order to enable an operator to visually judge whether the reaction cavity 2 leaks, the high-efficiency dust removal tail gas treatment system further comprises a water level observation tube 9, the side wall of the reaction cavity 2 is of a sandwich structure and comprises an inner layer and an outer layer, a cavity between the inner layer and the outer layer is a sandwich cavity, and the water level observation tube 9 is communicated with the sandwich cavity between the inner layer and the outer layer, so that once the inner layer of the reaction cavity 2 leaks due to corrosion, leaked water can enter the sandwich cavity, and since the water level observation tube 9 is communicated with the sandwich cavity, accordingly, the water level rise in the water level observation tube 9 can be observed correspondingly, and therefore early warning can be provided for the operator, and the operator is reminded that the inner layer of the reaction cavity 2 leaks without disassembling the reaction cavity 2.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.

Claims

1. The tail gas treatment system for efficient dust removal is characterized by comprising a combustion reactor, a water tank, a spray tower, an electrified dust remover and an air outlet pipe which are sequentially connected along the flow direction of tail gas;

the electrified dust remover comprises an anode precipitation cylinder and a cathode arranged in the anode precipitation cylinder, the anode precipitation cylinder is connected with a gas outlet of the spray tower, the cathode is connected with the power supply unit, and the anode precipitation cylinder is grounded.

2. The high-efficiency dust removal tail gas treatment system according to claim 1, wherein the combustion reactor and the spray tower are both arranged above the water tank, and the charged dust remover is arranged above the spray tower.

3. The tail gas treatment system for efficient dust removal according to claim 1, wherein the combustion reactor comprises a thermal decomposition chamber, a reaction chamber and a heating unit, the thermal decomposition chamber is located above the reaction chamber, the thermal decomposition chamber and the reaction chamber are communicated through a fluid rotating flange without an overlapping area, a liquid outlet of the fluid rotating flange is communicated with the reaction chamber, and the fluid rotating flange is used for forming a spiral water film flowing spirally on the inner wall of the reaction chamber and driving the tail gas in the reaction chamber to rotate.

4. The high-efficiency dust removal tail gas treatment system as claimed in claim 1, wherein the water tank comprises a tank body, an anti-corrosion layer arranged on the inner wall of the tank body, and a water pump arranged above the tank body, and liquid in the tank body is supplied into the spray tower and the fluid rotating flange through the water pump.

5. The tail gas treatment system for efficient dust removal according to claim 1, wherein the spray tower comprises a spray box, an anticorrosive layer arranged on the inner wall of the spray box, and a filler layer, a spray nozzle and a multi-mesh material layer which are arranged in the spray box;

the packing layer, the spray nozzle and the multi-mesh material layer are sequentially arranged along the direction from the air inlet to the air outlet of the spray box.

6. The tail gas treatment system for high-efficiency dust removal according to any one of claims 1 to 5, wherein a wall cleaning nozzle is arranged at one end of the anode precipitation cylinder, which is far away from the spray tower.

7. The high efficiency dust removal exhaust treatment system according to any one of claims 1 to 5, wherein the spray tower is connected to the anode precipitation tank through a buffer tube.

8. The high efficiency dust extraction exhaust treatment system of claim 7, wherein the buffer tube has a gradually increasing cross-sectional area from the spray tower to the anode precipitation cylinder.

9. The exhaust gas treatment system for high-efficiency dust removal according to claim 7, wherein a plurality of flow equalizing plates are axially disposed on one end of the buffer tube close to the spray tower, flow equalizing holes are formed in the flow equalizing plates, and the flow equalizing holes in two adjacent flow equalizing plates are staggered.

10. The high-efficiency dust removal tail gas treatment system according to any one of claims 1 to 5 and 8 to 9, wherein the tail gas treatment system is suitable for collecting dust particles with the particle size of 0.1-100 μm.