CN108079759B

CN108079759B - Plasma equipment for treating pollutant in gas

Info

Publication number: CN108079759B
Application number: CN201810143657.1A
Authority: CN
Inventors: 王雨化
Original assignee: Shanghai Rui Construction Environmental Technology Co Ltd
Current assignee: Shanghai Rui Construction Environmental Technology Co Ltd
Priority date: 2018-02-09
Filing date: 2018-02-09
Publication date: 2020-03-06
Anticipated expiration: 2038-02-09
Also published as: CN108079759A; WO2019154304A1

Abstract

The invention discloses a plasma device for treating pollutants in gas, which comprises: the plasma treatment device comprises a treatment cavity and a plurality of electrodes, wherein the electrodes are fixed on the inner wall of the treatment cavity in a distributed manner and used for generating plasma so as to carry out plasma treatment on gas to be treated flowing through the treatment cavity to degrade pollutants in the gas; each electrode comprises a substrate, a columnar structure array and a needle-shaped structure array, wherein the columnar structure array is formed on the substrate and comprises a plurality of columnar structures; the needle-shaped structure array is formed on the substrate outside the plurality of columnar structures and at the bottoms of the plurality of columnar structures, and comprises a plurality of needle-shaped structures. By arranging the distributed electrodes in the processing cavity and replacing the existing integrated electrodes with the distributed electrodes, the efficiency of generating plasma in an electric field around the electrodes is improved, and the efficiency of treating pollutants in gas by the plasma is further improved.

Description

Plasma equipment for treating pollutant in gas

Technical Field

The invention relates to the technical field of plasma, in particular to plasma equipment for treating pollutants in gas.

Background

With the increasing degree of industrialization in China, the generated gas pollution is also increasingly serious, especially in the aspect of Volatile Organic Compounds (VOCs). Different from the prior art that a thermal power plant is centralized and a large amount of pollutant gas containing sulfur and nitrate, the volatile organic pollutant gas has the technical characteristics of disordered discharge, complex pollutant components, low overall concentration and the like, thereby causing great difficulty in enterprise management and government management.

The existing methods for treating VOCs in gas mainly focus on two modes, namely a regenerative thermal incineration method and a regenerative catalytic combustion method. The principle of the Regenerative Thermal Oxidation (RTO) is to heat organic waste gas to over 760 ℃ to oxidize and decompose the VOCs in the waste gas, and the generated high-temperature gas flows through and heats the ceramic heat accumulator to store heat, which can be used to preheat the subsequent organic waste gas to save fuel consumption, which is common in the decomposition of medium-low concentration VOCs. The Regenerative Catalytic Oxidation (RCO) has the characteristics of high-efficiency recovery of thermal energy by RTO and the advantage of low-temperature operation of Catalytic reaction, and the catalyst is placed above the heat storage material, can oxidize the waste gas at a low temperature of more than 200 ℃, and is applied to occasions with high waste gas concentration.

However, the above conventional gas treatment technology is mainly directed to the chemical production units of mass production, and mainly treats the high-concentration VOCs waste gas, so that the construction cost and the maintenance cost are high, and the gas treatment technology is not suitable for the occasions where a large amount of small-displacement and low-concentration VOCs waste gas is treated. The plasma has technical advantages in principle for treating pollutants in gas, especially low-concentration VOCs, and charged particles in the plasma have physical and chemical actions with gas molecules under an electric field to directly degrade the pollutant gas molecules; in the aspect of engineering application, the method also has the great advantages of less material consumption, convenient maintenance and no selectivity to the gas to be treated, and can treat various pollutant gases simultaneously. However, the conventional plasma generator structure mostly adopts a parallel flat plate or a coaxial cylinder, a cylinder and other structures, and is difficult to maintain or control the generation and transportation of plasma in a discharge space, so that the efficiency of pollutant gas treatment is easily weakened.

Therefore, in order to solve the increasingly severe gas pollution environment faced by the public, there is a need for improvement of related plasma equipment in response to the technical requirement of plasma processing of VOCs pollutants in gases.

Disclosure of Invention

The invention provides a plasma device for treating pollutants in gas, which is used for treating the pollutants in the gas more effectively.

In order to solve the above problems, the present invention provides a plasma apparatus for treating contaminants in a gas, comprising:

the treatment cavity is provided with a gas flow inlet end and a gas flow outlet end, and gas to be treated enters from the gas flow inlet end and flows out from the gas flow outlet end;

the electrodes are fixed on the inner wall of the processing cavity in a distributed mode and used for generating plasma so as to carry out plasma processing on the gas to be processed flowing through the processing cavity and degrade pollutants in the gas;

each electrode comprises a substrate, a columnar structure array and a needle-shaped structure array, wherein the columnar structure array is formed on the substrate and comprises a plurality of columnar structures; the needle-shaped structure array is formed on the substrate outside the plurality of columnar structures and at the bottoms of the plurality of columnar structures, and comprises a plurality of needle-shaped structures.

In one embodiment of the invention, each electrode is independently connected to an external driving circuit to independently control the generation of plasma by the external circuit.

In an embodiment of the present invention, the apparatus further includes a gas sensor disposed in the processing chamber, and configured to collect, in real time, concentration information of the gas in the processing chamber, and feed back the collected concentration information of the gas to an external control circuit; and the external control circuit adjusts the driving parameters of the external driving circuit according to the received concentration information of the gas.

In one embodiment of the invention, the gas sensor is disposed at both the gas flow inlet end and the gas flow outlet end of the processing chamber.

In one embodiment of the invention, part of the electrodes in the plurality of electrodes are also connected with an external sensing driving signal to be used as the gas sensor.

In one embodiment of the invention, the plurality of electrodes are equally spaced in an axial direction of the process chamber and equally centered on a radial cross-sectional plane of the process chamber.

In one embodiment of the invention, the number of electrodes on the same plane in axial position is not less than 2.

In one embodiment of the invention, the axial position of the electrode is not less than 2.

In one embodiment of the invention, the projections of the electrodes on different radial cross-sectional planes on the same radial cross-sectional plane coincide or are arranged with an angular difference.

In one embodiment of the invention, the device further comprises a water washing or filter element pre-treatment section, and the water washing or filter element pre-treatment section is arranged at the airflow inlet end of the treatment cavity.

In one embodiment of the invention, the device further comprises an ozone treatment section, wherein the ozone treatment section is arranged at the airflow outlet end of the treatment cavity.

In one embodiment of the invention, the inner diameter of the treatment chamber is no greater than 300 mm and the size of the electrode is no greater than 3 cm.

In one embodiment of the present invention, needle-like structures are also formed on the top and/or the side walls of the plurality of columnar structures.

In one embodiment of the present invention, the tips of the needle-like structures form a heterojunction structure with the metal particles.

In one embodiment of the invention, the number of the processing chambers is multiple, and the multiple processing chambers are connected in series or in parallel.

Due to the adoption of the technical scheme, compared with the prior art, the invention has the following advantages and positive effects:

1) according to the plasma equipment for treating the pollutants in the gas, the distributed electrodes are arranged in the treatment cavity and replace the conventional integrated electrodes, so that the efficiency of generating plasma in an electric field around the electrodes is improved, and the efficiency of treating the pollutants in the gas by the plasma is further improved.

2) According to the plasma equipment for treating the pollutants in the gas, provided by the invention, each electrode is independently connected with the external driving circuit or the signal circuit so as to independently control the generation of the plasma by the external circuit, and the adjustment of the working state of each electrode is realized through the modulation of the external circuit, so that the density and the distribution of the plasma in the treatment cavity are controlled, and the refinement of the treatment of the pollutants in the gas is further improved.

3) According to the plasma equipment for treating pollutants in gas, the gas sensor is arranged in the treatment cavity and used for acquiring the concentration information of the gas in the treatment cavity in real time and feeding back the acquired concentration information of the gas to the external control circuit; and the external control circuit adjusts the driving parameters of the external driving circuit according to the received concentration information of the gas. Therefore, the matching of the plasma state and the pollutant content in the treated gas is realized, and the technical effects of high efficiency and energy saving are achieved.

4) According to the plasma equipment for treating pollutants in gas, provided by the invention, the external sensing driving signal is accessed to part of the electrodes to provide the concentration information of the gas in the treatment cavity in real time, and part of the electrodes are skillfully utilized to be used as gas sensors, so that the equipment is simpler and more compact in structure and lower in cost.

5) According to the plasma equipment for treating the pollutants in the gas, provided by the invention, the electrodes are distributed in a uniform topological manner, and the flow field control effect on the gas in the treatment cavity is also realized by combining the distance difference, the angle difference and the working time difference on the position, so that the regulation of the treatment speed of the pollutants in the gas is facilitated.

6) According to the plasma equipment for treating pollutants in gas, the electrode fully utilizes the cross-scale matching of the columnar structure and the needle-shaped structure, wherein the needle-shaped structure has a geometric tip effect (namely the top end of the structure with high length-diameter ratio can generate a local enhanced electric field), and the local electric field is gathered to promote the direct conversion of the gas to a plasma state; the side wall of the columnar structure contains a large number of surface states, so that the propagation and maintenance of plasma in the diffusion process in the space can be further promoted, and high-density plasma distribution in a large range can be formed efficiently under the condition of low voltage driving.

7) The plasma equipment for processing pollutants in gas provided by the invention has the advantages that the columnar structure of the electrode can form a needle-shaped structure on the top end and/or the side wall of the columnar structure besides the needle-shaped structure is distributed on the bottom, and the tip effect and the surface state effect can form a large-range high-density plasma distribution under a lower driving voltage.

8) According to the plasma equipment for treating pollutants in gas, the top end of the needle-shaped structure of the electrode and the metal particles form a metal particle-needle structure heterojunction structure, and the heterojunction structure can provide more surface states, so that electrons are more likely to be separated from neutral gas molecules in the process of ionizing gas molecules to form plasma, and the generation efficiency of the plasma is further improved.

Drawings

FIG. 1 is a schematic perspective view of a plasma apparatus for treating contaminants in a gas according to an embodiment of the present invention;

FIG. 2 is a left side view of a plasma apparatus for treating contaminants in a gas provided by an embodiment of the present invention;

FIG. 3 is a schematic diagram of the distribution of various electrodes in a plasma apparatus for treating contaminants in a gas, according to an embodiment of the present invention;

fig. 4 is a schematic perspective view of an electrode in a plasma apparatus for treating contaminants in a gas according to an embodiment of the present invention.

In the figure: 1-process chamber, 2-electrode, 21-substrate, 22-columnar structure, 23-needle structure, a 1-first electrode, a 2-third electrode, a 3-fourth electrode, b 1-second electrode, b 2-fifth electrode, b 3-sixth electrode, c 1-seventh electrode, c 2-eighth electrode, c 3-ninth electrode.

Detailed Description

The plasma apparatus for treating contaminants in a gas according to the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments. Advantages and features of the present invention will become apparent from the following description and from the claims. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present invention.

Before the present invention is proposed, the present inventors have conducted intensive studies on a plasma apparatus for treating contaminants in a gas, which is currently possible, as follows:

1) plasma devices for treating pollutants in gases have been reported, the electrodes of which generally take the shape of parallel plates or coaxial parallel cylinders, in which it is desired to achieve a spatial distribution of the plasma that matches the extent of the electrodes; in order to further reduce the initial voltage of plasma generated by gas discharge, the conventional electrode surface is also designed with a tip shape in a macro scale, or is provided with a micro-nano needle-like material/structure in a micro scale. However, since the discharge between the electrode plates occurs preferentially at the tip of the surface protrusion or the micro-scale needle tip, and the discharge generation at other positions of the same electrode with the equal potential is suppressed, the expected technical effect of the spatial distribution of the plasma matching with the electrode range is difficult to achieve, thereby reducing the removal efficiency of the pollutants in the gas.

2) The reported plasma devices for treating pollutants in gases usually employ a pair of electrodes, i.e. a system of two opposite electrodes, so that the technical means, controllable parameter types and control value range for controlling the electrodes to generate plasma by driving circuit signal changes are quite limited. For example, assuming that the plasma density distribution from the inlet end to the outlet end can only be raised and lowered integrally by changing the driving voltage through the parallel electrode plates of the whole processing chamber, however, since a large amount of intermediate states and charged particles generated at the inlet end position migrate to the outlet end direction along with the flow field, more effective plasma generation efficiency near the outlet end is facilitated, that is, imbalance of the axial distribution of the plasma is caused, which is not beneficial to removing pollutants in the gas.

3) Plasma equipment for treating pollutants in gas is reported, wherein an electrode structure is only used for generating plasma to generate physical and chemical reaction with pollutant molecules to be treated, and voltage and current signals on the electrode are mainly monitored for preventing overload, ignition and other safety related considerations. Research results show that the electrical signal of the electrode of the plasma generator has great correlation with the characteristics of the gas components between the electrodes, and the electrode can be used as a gas sensing device. However, in the current plasma generator for treating pollutants in gas, the electrode is an integral structure only reaching the function of the treatment gas, the monitoring of the gas composition at the local position of the treatment cavity is neither accurate nor practical, and a matched gas sensor is often required to provide feedback, so that the cost, the volume and the complexity of the system are increased.

4) The reported electrode structure of the plasma generator, such as the needle structure directly introduced into the micro-nano scale, microscopically utilizes the surface state provided by the needle structure, and has been proved to promote more charge energy transfer required for ionization, but because only the needle structure is adopted, the effective range is still limited to the surface of the needle structure, and the electrode structure cannot be effectively maintained and promoted in the space where the plasma diffuses and drifts.

The applicant discovers that the whole of the traditional integrated plasma generating electrode is broken into parts, and more means can be provided for controlling plasma by utilizing a discrete small gas discharge electrode and independent driving of each electrode through the design research on the microstructure, spatial distribution and driving mode of the plasma generator and the physical experiment of gas discharge; a sensing system for monitoring gas components is formed by utilizing a part of electrodes, and the change of the gas components is collected to be used as the basis for adjusting the state of the plasma, so that the efficiency and the technical effect of treating pollutants in the gas by the plasma are further optimized. In addition, through research on the aspect of plasma generation mechanism and experiments of generating plasmas through a large amount of gas discharge, the combination of a needle-shaped structure with the diameter ranging from several micrometers to nanometer scales and a micrometer-scale columnar structure is found, the defect that the action range of a plasma generator electrode fine structure in the process of generating plasmas is limited can be effectively overcome, and the enhancement effect of plasma generation locally extends from the tip of the needle-shaped structure to a diffusion space formed by the columnar structure.

Based on the above research, the inventors of the present application have creatively designed a plasma apparatus for treating pollutants in a gas, please refer to fig. 1 and fig. 2, and as shown in fig. 1 and fig. 2, the present embodiment provides a plasma apparatus for treating pollutants in a gas, which includes a processing chamber 1 and a plurality of electrodes 2, wherein the processing chamber 1 has a gas flow inlet end and a gas flow outlet end, and a gas to be treated enters from the gas flow inlet end and flows out from the gas flow outlet end. A plurality of electrodes 2 are distributively fixed on the inner wall of the processing chamber 1, and the plurality of electrodes 2 are used for generating plasma to perform plasma processing on the gas to be processed flowing through the processing chamber 1 so as to degrade pollutants in the gas.

As shown in fig. 4, each electrode 2 includes a substrate 21, a columnar structure array formed on the substrate 21, and a needle-like structure array including a plurality of columnar structures 22; an array of needle-like structures is formed on the substrate 21 outside the plurality of pillar-like structures 22 and at the bottom of the plurality of pillar-like structures 22, the array of needle-like structures including a plurality of needle-like structures 23. The electrode fully utilizes the cross-scale matching of the columnar structure and the needle-shaped structure, wherein the needle-shaped structure has a tip effect in geometry (namely the top end of the structure with high length-diameter ratio can generate a local enhanced electric field), and the local electric field is concentrated to promote the direct conversion of gas to a plasma state; the side wall of the columnar structure contains a large number of surface states, so that the propagation and maintenance of plasma in the diffusion process in the space can be further promoted, and high-density plasma distribution in a large range can be formed efficiently under the condition of low voltage driving.

As a preferred embodiment, each electrode 2 is independently connected to an external driving circuit to independently control the generation of plasma by the external circuit. The distributed electrode structure ensures that the plasma can be present at each position near the electrode in the processing chamber, and the driving circuit independently connected with the electrode can further adjust the parameters of the plasma near the electrode, such as generation or stop, density, electron temperature, diffusion range and the like. Specifically, the external driving circuit generates a driving voltage to the corresponding electrode, the driving voltage may be, for example, a direct current, an alternating current or a pulse high voltage, and the generation efficiency and the controllability of the plasma can be further optimized by combining the applied voltage with the spatial position distribution of the electrode.

As a preferred embodiment, the apparatus further comprises a gas sensor, disposed in the processing chamber 1, and configured to collect, in real time, concentration information of the gas in the processing chamber 1, and feed back the collected concentration information of the gas to an external control circuit; the external control circuit adjusts the drive parameters of the external drive circuit according to the received concentration information of the gas. So that the generation efficiency and controllability of the plasma can be further optimized.

As a further preferred embodiment, both the gas flow inlet end and the gas flow outlet end of the process chamber 1 are provided with gas sensors.

In order to make the device more compact, the applicant skillfully utilizes partial electrodes as gas sensors, and particularly realizes the function of the gas sensors by additionally connecting the partial electrodes into external sensing driving signals, so as to acquire the concentration information of the gas in the processing chamber 1 near the electrodes in real time. In the environment in which the processing chamber operates, the types of the processed gases are generally relatively fixed, and the concentration may fluctuate to some extent; as far as the processing chamber is concerned, the efficiency of removing the pollutants in the gas is attenuated to a certain extent along with the aging of the components such as the electrode, the power supply and the like, and the concentration of the processed gas is changed to a certain extent under the same processing parameters. The ionization of gas under strong electric field will produce discharge current, the initial voltage of the discharge process is related to the gas type, the magnitude of the current will correspond to the concentration of the gas, therefore, we only need to monitor the voltage current signal flowing on the discharge electrode in real time, as feedback, the driving signal on each plasma generator electrode of the processing section can be adjusted accordingly, thereby more finely and efficiently regulating and controlling the processing section. Since the principle of gas discharge is still used in nature, the electrode used for gas treatment itself can also be used for gas sensing, resulting in higher overall integration and lower cost.

As a preferred embodiment, the plurality of electrodes 2 are equally spaced in the axial direction of the process chamber and equally centered on a radial cross-sectional plane of the process chamber. That is, the positions of the electrodes 2 on the inner surface of the process chamber 1 will be periodically distributed on the coordinates with the central axis of the process chamber 1 as the linear coordinate, as exemplified by the number of electrodes on the radial section of the process chamber being 3, as shown in fig. 1, the coordinates of the electrodes 2 on the axial line will be concentrated on 3 points, and the distance between two adjacent points is the same; meanwhile, the electrodes with the same axis coordinate are positioned on the same radial cross section plane, and the electrodes are uniformly distributed relative to the axis when viewed from the left side, as in the device for treating pollutants in gas by using plasma in fig. 1, the electrode 2 has 3 electrodes on any radial cross section plane, and the central angles formed by adjacent electrodes are equal and are 120 degrees.

As a preferred embodiment, the number of the electrodes 2 on the same plane at the axial position is not less than 2, that is, at least one pair of electrode pairs on the same radial cross-sectional plane, and the electrodes can generate plasma with distribution characteristics meeting the treatment requirements of pollutants in the gas at the axial position through voltage drive control.

As a preferred embodiment, the axial position of the electrode is not less than 2, namely the coordinate of the electrode on the inner wall of the processing chamber 1 is not less than 2 on the axial line, namely the radial section plane containing the electrode is not less than 2, so as to ensure that the plasma can be regulated in a segmented mode in the gas flow direction.

As a further preferred embodiment, the projections of the electrodes on different radial cross-sectional planes onto the same radial cross-sectional plane coincide or are arranged with an angular difference. As shown in fig. 2, the electrodes on the radial plane at the center position in the axial direction have a central angle difference of 60 degrees as a whole from the electrodes on the other radial planes in the left side view. Such a design facilitates the formation of a specific plasma guiding flow field.

As a further preferred embodiment, a water washing or filter element pre-treatment section is further arranged at the gas flow inlet end of the treatment chamber 1, and the pre-washing or filter element can primarily remove part of particulate matters, so as to help protect the plasma electrode.

As a further preferred embodiment, an ozone treatment section is provided at the air flow outlet end of the treatment chamber 1 to remove ozone inevitably generated by the electrode 2 during operation.

Wherein, as an embodiment, the inner diameter of the processing chamber 1 is not more than 300 mm, and the size of the electrode 2 is not more than 3 cm. The size ratio of the electrode 2 to the processing chamber 1 can ensure the concentration of the plasma generated in the processing chamber 1 and ensure that the gas flowing through the processing chamber 1 is effectively purified.

In practical applications, the number of the processing chambers 1 may be provided in plural, and the plural processing chambers are connected in series or in parallel. In particular, the serial connection is suitable for larger gas fluxes to be treated in order to cope with the more stringent treatment requirements of pollutants in the gas.

Referring to fig. 4, in the electrode 2 of the present invention, as a preferred embodiment, needle-like structures are also formed on the top and/or side walls of the plurality of pillar-like structures 22, and the needle-like structures may be, for example, carbon nanotubes, zinc oxide nanowires, silicon carbide nanowires, silicon nanometers, gallium arsenide nanowires, gallium nitride nanowires, etc. By providing needle-like structures on the tips and/or sidewalls of the columnar structures 22, a greater contact area and opportunity with the plasma is provided, which positively facilitates the maintenance and proliferation of the plasma movement.

As a further preferred embodiment, the tip of the needle-like structure 23 forms a heterojunction structure with the metal particles, so that the surface state effect provided by the metal particles can be superimposed on the tip effect, further promoting the plasma generation.

The substrate 21 is a silicon wafer, and in order to ensure effective transmission of driving signals, a high-conductivity silicon wafer with low resistivity is preferably selected, wherein the high-conductivity silicon wafer refers to a silicon wafer with the resistivity below dozens of ohm-cm level. Of course, the invention is not limited thereto, and other materials can be selected as the substrate. The columnar structure array is formed by etching the substrate, and the aspect ratio (width-to-depth ratio) of the single columnar structure 22 is not less than 2, and the height is not less than 100 microns. Preferably, the spacing between adjacent columnar structures 22 in the columnar structure array is not less than the diameter of the columnar structures 22 to ensure sufficient geometric effects and provide sufficient surface states during plasma propagation and movement. Wherein, the etching adopts a graphical catalyst film as a catalyst. Specifically, the patterned catalyst thin film includes a lower thin film, the lower thin film is in contact with the substrate 21, and the lower thin film is made of a noble metal and is used for catalyzing etching of the substrate to form a columnar structure. The patterned catalyst film also comprises an upper film, the upper film is positioned on the lower film, and the upper film is made of any one or combination of iron, gold, silver, titanium, palladium, nickel, gallium, zinc and alloy and/or oxide thereof and is used for catalyzing the growth of the needle-shaped structure.

In addition, the aspect ratio of the individual needle-like structures 23 is not less than 10 and the diameter is not more than 10 μm to ensure the tip effect of the needle-like structures 23 during the plasma generation.

Referring to fig. 3, the method for using the plasma apparatus for treating the contaminants in the gas according to the present embodiment includes the following steps:

s101, initially collecting concentration information of gas in a processing cavity;

specifically, an external sensing driving signal is applied to a part of electrodes disposed at a gas flow inlet end of the processing chamber, for example, the first electrode a1 is applied with the external sensing driving signal, the second electrode b1 is grounded, and an electric field required for generating plasma by gas discharge is formed, so that the first electrode a1 and the second electrode b1 serve as gas sensors; the external sensing driving signal is, for example, a scanning type direct current voltage gradually increased from 0V to 10kV, when the loading voltage exceeds the discharge threshold voltage, a current signal is generated in the circuit loop, and electric signals such as a discharge starting voltage, a discharge current and the like are collected and sent to the external control circuit;

s102, carrying out plasma processing on the gas in the processing chamber

An external control circuit controls an external driving circuit to drive electrodes of the whole section of the processing cavity, and plasma processing is performed on the air flow flowing through the processing cavity, wherein driving signals loaded on the electrodes are independently controlled, for example, a positive high voltage of 10kV level is loaded on a first electrode a1, a third electrode a2 and a fourth electrode a3, a second electrode b1, a fifth electrode b2 and a sixth electrode b3 are grounded, a negative high voltage of 10kV level with the same magnitude but opposite polarity as the loading voltage loaded on the first electrode a1, the third electrode a2 and the fourth electrode a3 is loaded on a seventh electrode c1, an eighth electrode c2 and a ninth electrode c3, and for any one of the electrodes, such as the grounded fifth electrode b2, a strong electric field is formed among the eighth electrode c2, the fourth electrode a3, the sixth electrode b3 and the third electrode a 2;

s103, collecting the concentration information of the gas in the processing cavity again;

specifically, an external sensing driving signal is applied to a part of the electrodes disposed at the gas flow outlet end of the processing chamber, for example, the fourth electrode a3 is applied with the external sensing driving signal, the sixth electrode b3 is grounded, and an electric field required for generating plasma by gas discharge is formed, so that the fourth electrode a3 and the sixth electrode b3 are used as gas sensors; the external sensing driving signal is, for example, a scanning type direct current voltage gradually increased from 0V to 10kV, when the loading voltage exceeds the discharge threshold voltage, a current signal is generated in the circuit loop, and electric signals such as a discharge starting voltage, a discharge current and the like are collected and sent to the external control circuit;

s104: adjusting parameters of a drive signal applied to an electrode

The external control circuit adjusts the driving parameters of the external driving circuit according to the acquired gas concentration information again, such as increasing the amplitudes of the voltages applied to the first electrode a1 and the seventh electrode c1 near the gas flow inlet end, shortening the duration of the driving voltages applied to the third electrode a2 and the eighth electrode c2 in the middle section, and reducing the amplitudes of the voltages applied to the fourth electrode a3 and the ninth electrode c3 near the gas flow outlet end.

S105: and repeating the steps S103-S104, and feeding back and optimizing the loaded driving signal according to the acquired sensing signal.

According to the plasma equipment for treating the pollutants in the gas, provided by the invention, the traditional integrated electrode is decomposed into the multipoint independently controlled plasma generating electrode, so that the fine control of the pollutants in the gas is realized, and the treatment efficiency is improved; the electrode for processing partial gas pollutants is skillfully applied to real-time monitoring of gas concentration information, and the provided feedback information further optimizes the technical effect of processing the pollutants in the gas.

The above description is only for the purpose of describing the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention, and any variations and modifications made by those skilled in the art based on the above disclosure are within the scope of the appended claims.

Claims

1. A plasma apparatus for treating contaminants in a gas, comprising:

2. The plasma apparatus for treating contaminants in a gas according to claim 1, wherein each electrode is independently connected to an external driving circuit to independently control the generation of the plasma by the external circuit.

3. The apparatus of claim 2, further comprising a gas sensor disposed within said process chamber for collecting information about the concentration of the gas within said process chamber in real time and feeding back the collected information about the concentration of the gas to an external control circuit; and the external control circuit adjusts the driving parameters of the external driving circuit according to the received concentration information of the gas.

4. A plasma apparatus for treating contaminants in a gas according to claim 3, wherein the gas sensor is disposed at both the gas flow inlet end and the gas flow outlet end of the process chamber.

5. The plasma apparatus for treating contaminants in a gas according to claim 3 or 4, wherein a portion of said plurality of electrodes are further coupled to an external sensing drive signal for use as said gas sensor.

6. The plasma apparatus for treating contaminants in a gas according to claim 1, wherein the plurality of electrodes are equally spaced in an axial direction of the process chamber and equally centered on a radial cross-sectional plane of the process chamber.

7. A plasma apparatus for treating contaminants in gases according to claim 6 wherein the number of electrodes on the same plane at the same axial position is no less than 2.

8. The plasma apparatus for treating contaminants in a gas according to claim 6, wherein the axial position of the electrode is not less than 2.

9. A plasma apparatus for treating contaminants in gases according to claim 6, wherein the projections of the electrodes on different radial cross-sectional planes onto the same radial cross-sectional plane coincide or are angularly offset.

10. A plasma apparatus for treating contaminants in a gas according to claim 1, further comprising a water wash or cartridge pre-treatment section disposed at a gas flow inlet end of the treatment chamber.

11. The plasma apparatus for treating contaminants in a gas according to claim 1 or 10, further comprising an ozone treatment section disposed at the gas flow outlet end of the treatment chamber.

12. The plasma apparatus for treating contaminants in a gas according to claim 1, wherein the process chamber has an inner diameter of no greater than 300 mm and the electrode has a dimension of no greater than 3 cm.

13. The apparatus of claim 1, wherein said columnar structures have needle-like structures formed on the top and/or sidewalls thereof.

14. The plasma apparatus for treating contaminants in a gas according to claim 1, wherein the tips of the needle-like structures form a heterojunction structure with the metal particles.

15. The plasma apparatus for treating contaminants in a gas according to claim 1, wherein the number of the process chambers is plural, and the plural process chambers are connected in series or in parallel.