CN108283869B

CN108283869B - Method for treating pollutants in gas by plasma

Info

Publication number: CN108283869B
Application number: CN201810143772.9A
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: WO2019154302A1; CN108283869A

Abstract

The invention discloses a method for processing pollutants in gas by plasma, which is characterized in that electrodes distributed in a processing cavity are independently controlled and driven, part of the electrodes are used as gas sensors to collect concentration information of the gas, and parameters of driving voltage loaded on the electrodes are adjusted according to the collected gas concentration information, so that the processing efficiency of the plasma formed in the processing cavity is continuously optimized, the matching of the state of the plasma and the content of the pollutants in the processed gas is realized, and the technical effects of high efficiency and energy saving are achieved; the refinement of the treatment of pollutants in the gas is improved.

Description

Method for treating pollutants in gas by plasma

Technical Field

The invention relates to the technical field of plasma, in particular to a method for treating pollutants in gas by using plasma.

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 the related plasma processing method for the technical requirement of plasma processing VOCs pollutants in the gas.

Disclosure of Invention

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

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

s1, performing plasma treatment on pollutants in the gas by using a plasma device; the plasma equipment comprises a processing cavity and a plurality of electrodes, wherein the electrodes are fixed on the inner wall of the processing cavity in a distributed manner; step S1 specifically includes:

s101, loading external sensing driving signals on partial electrodes arranged at the gas flow inlet end of a processing cavity, enabling the electrodes to be used as gas sensors, and initially collecting concentration information of gas in the processing cavity;

s102, independently loading external voltage driving signals to all electrodes in the processing cavity, forming plasma in the processing cavity, and carrying out plasma processing on gas in the processing cavity;

s103, loading external sensing driving signals on partial electrodes arranged at the airflow outlet end of the processing cavity, enabling the electrodes to be used as gas sensors, and collecting concentration information of gas in the processing cavity again;

s104, optimizing the parameters of the external voltage driving signals loaded on each electrode according to the concentration information of the gas collected again;

s105: the above steps S103 to S104 are repeated so that the parameters of the external voltage driving signals loaded on the respective electrodes are continuously optimized.

In one embodiment of the present invention, the external sensing driving signal is loaded by an external sensing driving circuit.

In one embodiment of the invention, the external voltage driving signal is loaded by an external voltage driving circuit.

In an embodiment of the present invention, between step S101 and step S102, S1011 is further included: the application of the external sensing drive signal to the partial electrode disposed at the gas flow inlet end of the process chamber is stopped.

In an embodiment of the present invention, between step S103 and step S104, S1031 is further included: and sending the concentration information of the gas collected again to an external control circuit.

In an embodiment of the present invention, the step S104 specifically includes: and the external control circuit adjusts the parameters of the external voltage driving signals loaded on each electrode according to the received concentration information of the gas collected again.

In an embodiment of the present invention, the parameters of the external voltage driving signal in step 104 include the amplitude of the driving voltage and the duration loading time of the driving voltage.

In an embodiment of the present invention, between step S103 and step S104, S1031 is further included: and stopping the application of the external sensing drive signal to the partial electrode arranged at the gas flow outlet end of the processing chamber.

In an embodiment of the present invention, before the step S1, the method further includes the step S0: and washing the gas with water or filtering the gas by a filter element.

In an embodiment of the present invention, after the step S1, the method further includes the step S2: and carrying out ozone treatment on the gas after the plasma treatment.

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 method for processing the pollutants in the gas by the plasma, the electrodes distributed in the processing cavity are independently controlled and driven, meanwhile, part of the electrodes are used as gas sensors, the concentration information of the gas is collected, and the parameters of the driving voltage loaded on the electrodes are adjusted according to the collected gas concentration information, so that the processing efficiency of the plasma formed in the processing cavity is continuously optimized, the matching of the state of the plasma and the content of the pollutants in the processed gas is realized, and the technical effects of high efficiency and energy saving are achieved; the refinement of the treatment of pollutants in the gas is 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 method for treating contaminants in a gas by using plasma 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 made, the present inventors have conducted intensive studies on the currently possible methods of plasma treating contaminants in gases, and the following were specifically studied:

1) reported methods for plasma treatment of contaminants in gases, using plasma equipment with electrodes generally in the form of parallel plates or concentric parallel cylinders, are intended to achieve a plasma spatial distribution matching 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 methods for treating pollutants in gas by plasma generally use 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 very 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) The reported method for treating pollutants in gas by plasma adopts the electrode structure of plasma equipment which is only set for generating plasma to generate physical and chemical reaction with pollutant molecules to be treated, and the monitoring of voltage and current signals on the electrode is mainly used 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.

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.

Based on the above research, the inventors of the present application have creatively devised a method of plasma treating contaminants in a gas, including S1 plasma treating the contaminants in the gas using a plasma apparatus; referring to fig. 1-3, the plasma apparatus includes a processing chamber 1 and a plurality of electrodes 2, wherein the plurality of electrodes 2 are distributively fixed on an inner wall of the processing chamber 1; step S1 specifically includes:

s101, loading external sensing driving signals on partial electrodes arranged at the gas flow inlet end of the processing cavity 1, enabling the electrodes to be used as gas sensors, and initially collecting concentration information of gas in the processing cavity;

specifically, as shown in fig. 3, an external sensing driving signal is applied to a portion of the electrodes disposed at the gas flow inlet end of the process 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 function 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;

specifically, the external control circuit controls the external driving circuit to drive the electrodes of the whole section of the processing chamber, and plasma processing is performed on the gas flow flowing through the processing chamber, wherein the driving signals loaded on the respective electrodes are independently controlled, for example, the first electrode a1, the third electrode a2 and the fourth electrode a3 are loaded with positive high voltage of 10kV level, the second electrode b1, the fifth electrode b2 and the sixth electrode b3 are grounded, the seventh electrode c1, the eighth electrode c2 and the ninth electrode c3 are loaded with 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, and for any one of the electrodes, for example, 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;

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;

specifically, 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 amplitude of the voltage applied to the first electrode a1 and the seventh electrode c1 near the gas flow inlet end, shortening the duration of the driving voltage applied to the third electrode a2 and the eighth electrode c2 in the middle section, and decreasing the amplitude of the voltage applied to the fourth electrode a3 and the ninth electrode c3 near the gas flow outlet end.

S105: the above steps S103 to S104 are repeated so that the parameters of the external voltage driving signals loaded on the respective electrodes are continuously optimized. The judgment standard for continuously optimizing the parameters of the external voltage driving signal is as follows: the discharge current of the electrode used as the gas sensor is maintained at a low level. This is because the electrical characteristics of the gas discharged in the electric field are related to the type and concentration of the gas itself, when the treatment effect is optimized, the concentration of the treated gas is low, and the electrical signal will show that the discharge current is lower than the initial discharge current under the condition of higher than the discharge initial voltage; so that the resulting discharge current of the gas sensor is also maintained at a low level.

And the external sensing driving signal is loaded through an external sensing driving circuit. The external voltage driving signal is loaded through the external voltage driving circuit.

Specifically, between step S101 and step S102, S1011 is further included: the application of the external sensing drive signal to the partial electrode disposed at the gas flow inlet end of the process chamber is stopped.

Between step S103 and step S104, S1031 is further included: and sending the concentration information of the gas collected again to an external control circuit.

As a preferred embodiment, the step S104 specifically includes: and the external control circuit adjusts the parameters of the external voltage driving signals loaded on each electrode according to the received concentration information of the gas collected again.

Specifically, the parameters of the external voltage driving signal in step 104 include the amplitude of the driving voltage and the duration of the loading time of the driving voltage.

Between step S103 and step S104, S1031 is further included: and stopping the application of the external sensing drive signal to the partial electrode arranged at the gas flow outlet end of the processing chamber.

As a preferred embodiment, before the step S1, the method further includes step S0: and washing the gas with water or filtering the gas by a filter element. The preposed water washing or the filter element can primarily remove partial particles, and the plasma electrode is protected. And the gas is washed by water before the plasma treatment, so that part of organic gas molecules can be hydrophilic to form a gas-micro liquid drop mixture; and thus may be degraded during plasma processing by ionizing the gas-droplet mixture. The gas to be treated is washed by water, and then the gas after washing is subjected to plasma treatment to degrade pollutants in the gas, so that the defect that the ionization of Volatile Organic Compounds (VOC) gas cannot be effectively promoted because the gas is only subjected to pre-filtration before the plasma treatment in the traditional method for treating the pollutants in the gas is solved.

As a preferred embodiment, after the step S1, the method further includes step S2: carrying out ozone treatment on the gas after the plasma treatment; ozone inevitably generated by the electrode 2 during operation can be removed.

Referring to fig. 1 and 2, as shown in fig. 1 and 2, the plasma processing apparatus for processing pollutants in a gas according to the present embodiment includes a processing chamber 1 and a plurality of electrodes 2, the processing chamber 1 has a gas flow inlet end and a gas flow outlet end, and a gas to be processed 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.

According to the method for processing the pollutants in the gas by the plasma, the electrodes distributed in the processing cavity are independently controlled and driven, meanwhile, part of the electrodes are used as gas sensors, the concentration information of the gas is collected, and the parameters of the driving voltage loaded on the electrodes are adjusted according to the collected gas concentration information, so that the processing efficiency of the plasma formed in the processing cavity is continuously optimized, the matching of the state of the plasma and the content of the pollutants in the processed gas is realized, and the technical effects of high efficiency and energy saving are achieved; the refinement of the treatment of pollutants in the gas is improved.

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 method for plasma processing contaminants in a gas, comprising:

s1: carrying out plasma treatment on pollutants in the gas by using a plasma device; the plasma equipment comprises a processing cavity and a plurality of electrodes, wherein the electrodes are fixed on the inner wall of the processing cavity in a distributed manner; step S1 specifically includes:

s101: loading external sensing driving signals on partial electrodes arranged at the airflow inlet end of the processing cavity, enabling the electrodes to be used as gas sensors, and initially collecting concentration information of gas in the processing cavity;

s102: independently loading external voltage driving signals to all electrodes in the processing cavity, forming plasma in the processing cavity, and carrying out plasma processing on gas in the processing cavity;

s103: loading external sensing driving signals on partial electrodes arranged at the airflow outlet end of the processing cavity, enabling the electrodes to be used as gas sensors, and acquiring concentration information of gas in the processing cavity again;

s104: optimizing parameters of external voltage driving signals loaded on each electrode according to the concentration information of the gas collected again;

2. The method of claim 1, wherein the external sense drive signal is applied by an external sense drive circuit.

3. The method of claim 1, wherein the external voltage drive signal is applied by an external voltage drive circuit.

4. The method of claim 1, further comprising between step S101 and step S102S 1011: the application of the external sensing drive signal to the partial electrode disposed at the gas flow inlet end of the process chamber is stopped.

5. A method for plasma processing contaminants in gases as claimed in claim 1, further comprising between step S103 and step S104S 1031: and sending the concentration information of the gas collected again to an external control circuit.

6. The method of claim 5, wherein the step S104 is embodied as: and the external control circuit adjusts the parameters of the external voltage driving signals loaded on each electrode according to the received concentration information of the gas collected again.

7. The method of claim 1, wherein the parameters of the external voltage driving signal in step S104 include the magnitude of the driving voltage and the duration of the driving voltage.

8. A method for plasma processing contaminants in gases as claimed in claim 1, further comprising between step S103 and step S104S 1031: and stopping the application of the external sensing drive signal to the partial electrode arranged at the gas flow outlet end of the processing chamber.

9. The method of claim 1, further comprising, before the step S1, S0: and washing the gas with water or filtering the gas by a filter element.

10. The method of claim 1 or 9, further comprising, after the step S1, S2: and carrying out ozone treatment on the gas after the plasma treatment.