CN111491435A - A Non-Jet Atmospheric Pressure Thermal Plasma Generator - Google Patents

Abstract

The invention discloses a non-jet normal pressure thermal plasma generator, belonging to the technical field of microwave plasma, comprising an igniter and a microwave source, and characterized in that: the microwave reaction device is characterized by further comprising a reaction cavity, wherein a gas channel I and a gas channel II are formed in the reaction cavity, the reaction cavity comprises a cylindrical cavity and a conical cavity located above the cylindrical cavity, the conical cavity is communicated with the cylindrical cavity, a microwave feed port is formed in the cylindrical cavity, a microwave source is connected with the microwave feed port, and an igniter is connected to the conical cavity. The invention can form thermal plasma with larger volume and uniformity, realize the full and uniform heating of gas to be treated, improve the reaction efficiency, can be uniformly distributed in a set space range, can effectively prevent destructive breakdown discharge, is easy to control the heat dissipation balance, ensures the reasonable temperature and stable structure of the whole generator and realizes the long-term operation stability under the condition of reducing the heat dissipation as much as possible.

Description

A Non-Jet Atmospheric Pressure Thermal Plasma Generator

technical field

The invention relates to the technical field of microwave plasma, in particular to a non-jet normal pressure thermal plasma generator.

Background technique

Plasma is the fourth state of existence of matter, usually refers to ionized or partially ionized conductive gas, which includes six typical particles: electrons, positive ions, negative ions, excited atoms or molecules, ground state atoms or molecules and photons. Whether it is partially ionized or fully ionized; the total number of negative charges is equal to the total number of positive charges, so it is called plasma, and it is generally electrically neutral in time and space at the macroscopic scale. The stricter definition is: Plasma is a collection of electrons, positive ions and neutral particles that are electrically neutral as a whole. Plasma is divided into two categories according to temperature: high temperature plasma and low temperature plasma. High-temperature plasmas are fully ionized plasmas with a temperature between 10 ⁸ -10 ⁹ K: such as solar, stellar, nuclear fusion plasmas. The low temperature plasma is further divided into hot plasma and cold plasma. Thermal plasma, the existence of high ambient pressure, at 1 atmosphere and above, the temperature range is 10 ³ -10 ⁵ K, and the electron temperature is roughly equal to the gas temperature, so it is also called "equilibrium plasma", as usual Piezoelectric arc discharge plasmas, high frequency induction plasmas, and combustion plasmas; cold plasmas, usually at low or atmospheric pressure, although the electron temperature range is still as high as 10 ³ -10 ⁴ K, the gas average temperature range is as low as 300 -400K, the electron temperature is much higher than the gas temperature, so it is also called "non-equilibrium plasma", such as DC glow discharge under low pressure or high frequency induced glow discharge plasma.

Plasma has unique physical and chemical properties: it has electrical conductivity similar to metal, and the whole is electrically neutral and can be affected by magnetic fields; high temperature, large kinetic energy of particles; active chemical properties, easy to occur chemical reactions; unique luminescence characteristics, etc. . The fundamental reason why plasma possesses these properties can be attributed to the collision, excitation, dissociation, and ionization between electrons and gas molecules to produce chemically active species or groups with unpaired electrons. It is precisely because of its unique properties in optics, electricity, mechanics, heat and chemistry that plasma technology has become an emerging technology and has been widely used. Due to the presence of a sufficient number of free charged particles, its behavior is significantly affected by the electromagnetic force, and overall it presents an electrically neutral, non-condensed system. Plasma has all electromagnetic properties, and its behavior differs from ordinary solids, liquids, and gases in many ways. The main characteristics are: there is long-range Coulomb force interaction between particles, and their motions are closely coupled with electromagnetic field motions, and there are abundant collective effects and collective motion patterns.

Usually high temperature plasma is not included in the field of conventional industrial applications and related research, while low temperature plasma has wider application and application value in this field. In the category of low temperature plasma, the traditional theory holds that the plasma required for chemical reaction should be a non-equilibrium plasma whose electron temperature is much higher than the gas temperature, that is, low temperature cold plasma. The average energy of the reacting gas increases, which manifests as a low average temperature. But in practical applications, the process of chemical reactions carried out in cold plasma is very different from conventional reactions at the same temperature, and it is not necessarily favorable. Because the low temperature exhibited by cold plasma is only an average concept, and there are local high temperature or some high temperature particles in it, the low temperature at this time is just a manifestation of extremely uneven temperature; at this time, the unevenness will cause most of the reactants Being in the low temperature region and far below the average temperature may affect the reaction rate and reaction speed; and the local high temperature may cause irreversible destruction of some reactants, resulting in a large number of unexpected by-products, affecting the utilization rate and yield. Thermal plasma, on the other hand, can provide a reaction environment that is highly concentrated in energy, high temperature and rich in highly reactive particles. A large number of highly active electrons, ions, atoms, and molecules in the excited state can promote many chemical reactions, which not only help to greatly improve the reaction rate, but also make some chemical reactions impossible at normal temperature possible. Moreover, the ideal thermal plasma electron temperature is roughly equal to the gas temperature. As long as the gas temperature is well controlled and suitable for the temperature required by the chemical reaction, a good reaction effect can be obtained. Although thermal plasma has the theoretical conditions to promote chemical reactions, the current common atmospheric thermal plasma devices usually only produce high-speed jet plasma torches, such as DC plasma torches and high-frequency plasma torches. The plasma generated by these devices is limited by the device and physical conditions: the plasma is generated and exists in an area with extremely high energy density, in a highly concentrated state, the plasma concentration area is small and the temperature is extremely high, in order to prevent the above-mentioned plasma diffusion high temperature If the device is affected or destroyed, a large amount of low-temperature auxiliary gas can only be introduced in the form of a jet to confine the plasma and blow it out in a directional manner, thereby forming a plasma jet. In order to achieve the above purpose, if the gas to be treated is passed into the plasma as an auxiliary gas, its flow rate must be much larger than the plasma flow rate, and 70%-90% of the gas will not pass through the plasma, and will not be fully heated or plasmaized. ; If other gas is used as auxiliary gas to blow out the plasma and send it into the gas to be treated, a large amount of useless gas will be introduced into the whole treatment system, and the effect will be worse. Therefore, in the jet plasma torch device, it is difficult to ensure that the gas to be treated can fully pass through the region where the plasma exists, and it is difficult to ensure that the gas to be treated is fully heated or plasmaized, thereby affecting the actual reaction effect. In addition, there is a problem of great difficulty in dissipating heat due to concentrated high temperature, which can easily lead to the melting, gasification, and plasmaization of the materials constituting the device, introducing impurities into the reaction system, and even damaging the equipment.

In theory, microwaves can also form plasma. According to Paschen's law and Paschen curve, it can be known that atmospheric pressure gas needs a high electric field strength to break down to form plasma; and microwave, as an electromagnetic wave, can form alternating electric and magnetic fields in space , as long as the microwave power in the unit space, that is, the microwave power density, reaches a sufficient intensity, the space alternating electric field will reach a sufficient intensity, and the atmospheric gas can be broken down to form a plasma. However, in ordinary microwave devices with low microwave power density, the electric field strength is weak, and its distribution is also dynamic and non-uniform, making it difficult to form plasma. Stable energy, energy migration, and thermal convection of plasma and gas will cause the plasma to drift around inside the microwave device, and it is very easy to drift out or drift to the vicinity of the microwave feed. The power density is much higher than that of the cavity, resulting in a destructive breakdown discharge. Increasing the microwave power density in this type of device can theoretically amplify and stabilize the plasma, but in fact, because the power density of the microwave feed port is higher at this time, and the volume of the plasma becomes larger, it is more likely to drift to the microwave Near the feed port, a destructive breakdown discharge is bound to be formed. As a result, stable atmospheric thermal plasma cannot be formed in ordinary microwave devices.

In the prior art, the only devices that can form relatively stable microwave plasma are the microwave plasma torches in the form of jets. This type of device focuses the microwaves to a very small point-like region or a very short linear region. And a very high microwave power density is formed in this area, which causes the normal pressure gas to break down; but at the same time, due to the high local microwave power density, only a very high temperature and small volume plasma core can be formed in a very small area, and Diffusion to the surrounding space; in order to prevent the damage to the device caused by the above-mentioned high temperature diffusion, a large amount of auxiliary gas can only be introduced in the form of a jet to confine the plasma and blow it out in a directional manner, so as to form a plasma jet, that is, to form a high temperature plasma as the axis The composite jet with the core and the low-temperature gas as the bushing is calculated from the cross section of the composite jet, and the proportion of plasma in the composite jet is only 10%-30%. Therefore, when a microwave plasma torch in the form of a jet is used to process the incoming gas, only a small part can be effectively heated and plasmaized, and a large amount of the gas to be treated cannot pass through the plasma area and cannot produce an effective reaction; The unfavorable side reaction may occur due to the high temperature of the gas, which makes the material utilization rate, processing efficiency and processing effect become poor, and it is difficult to put into practical application. Moreover, the addition of a large amount of auxiliary gas not only increases the processing burden of the microwave plasma device, but also increases the separation burden of the subsequent device, and also reduces the reaction efficiency. In addition, since the plasma startup area of this type of device is the same area as the subsequent continuous working area, the microwave power density in the working area is very high during low-power operation. If a high-power plasma device is required, the microwave power density in the working area, plasma The body temperature and concentration will be extremely high. At this time, limited by the structure of the microwave transmission system and heat dissipation, the microwave power that can be loaded is small and the upper limit of the power is low, which is greatly limited; in addition, if the microwave power is too large, the plasma temperature and concentration Too high and the assist gas also struggles to reliably confine the plasma and form a jet, which can eventually lead to unstable operation or damage to the device. Therefore, such devices are also greatly limited in industrial applications requiring high efficiency, large output, and high power.

The publication number is CN 105979693A, and the Chinese patent document with the publication date of September 28, 2016 discloses a high-power microwave plasma generating device, which is characterized in that: a microwave generator, a three-terminal circulator, a load, and a three-pin tuning The microwave generator is connected with the three-terminal circulator, the three-terminal circulator is connected with the load and the three-pin tuner, and the three-pin tuner is connected with the waveguide-to-coaxial joint. The connector connects to the torch.

In the high-power microwave plasma generating device disclosed in this patent document, the microwave coupling position is selected at least one-half wavelength away from the upper end face of the torch, which can prevent the problem of overheating of the coaxial microwave transmission joint under high power. The structure with additional heat sinks on the outer surface further solves the problem of heat dissipation when the torch is working, and can withstand kilowatt-level power, ensuring that the plasma generating device works well under high-power working conditions. However, a large amount of auxiliary gas is required to effectively confine and orient the plasma, and a large amount of gas to be treated cannot pass through the plasma region and cannot produce an effective reaction; and the gas passing through the plasma region may have adverse side reactions due to excessive temperature, causing Material utilization, processing efficiency and processing effect all become poor. In addition, if the microwave power is too high, and the plasma temperature and concentration are too high, it is difficult for the auxiliary gas to reliably confine the plasma and form a jet, which can eventually lead to unstable operation or device damage. Moreover, the addition of a large amount of auxiliary gas not only increases the processing burden of the microwave plasma device, but also increases the separation burden of the subsequent device, and also reduces the reaction efficiency. In addition, since the plasma startup area of this type of device is the same area as the subsequent continuous working area, the microwave power density in the working area is very high during low-power operation. If a high-power plasma device is required, the microwave power density in the working area, plasma The body temperature and concentration will be extremely high. At this time, limited by the structure of the microwave transmission system and heat dissipation, the loadable microwave power is small and the power upper limit is low, which is greatly limited. For industrial applications, tens of kilowatts, hundreds of kilowatts, The long-term continuous application of the kilowatt order is still unsatisfactory.

SUMMARY OF THE INVENTION

In order to overcome the above-mentioned defects of the prior art, the present invention provides a non-jet normal pressure thermal plasma generator. The present invention can form a large and uniform thermal plasma, realize sufficient and uniform heating of the gas to be treated, and improve the reaction efficiency. , and can be evenly distributed within the set space range, which can effectively prevent the generation of destructive breakdown discharge, and is easy to control the heat dissipation balance. In the case of minimizing heat dissipation, the temperature of the entire generator is guaranteed to be reasonable and the structure is stable, so as to achieve long-term Operational stability.

The present invention is achieved through the following technical solutions:

A non-jet normal-pressure thermal plasma generator, comprising an igniter and a microwave source, and characterized in that: it also includes a reaction cavity, the reaction cavity is provided with a gas channel I and a gas channel II, and the reaction cavity includes a column A cavity and a conical cavity located above the cylindrical cavity, the conical cavity is communicated with the cylindrical cavity, the cylindrical cavity is provided with a microwave feed port, the microwave source is connected to the microwave feed port, and the igniter is connected to the on the conical cavity.

The reaction chamber is a double-layer metal structure, including an inner chamber and an outer chamber, and an interlayer for passing a fluid medium is formed between the inner chamber and the outer chamber.

The inner wall of the inner cavity of the conical cavity is lined with a thermal insulation layer, and the thickness of the thermal insulation layer is 5-200 mm.

The thermal insulation layer is an aluminum oxide thermal insulation layer, a zirconia thermal insulation layer, a silicon oxide thermal insulation layer, a silicon thermal insulation layer, a graphite thermal insulation layer, a silicon nitride thermal insulation layer, a carbon nitride thermal insulation layer or a nitrided thermal insulation layer. Boron insulation.

A wave-transmitting baffle is fixedly connected in the cylindrical cavity, the wave-transmitting baffle and the cylindrical cavity form a microwave feeding area, and the microwave feeding port is located in the microwave feeding area.

A wave-transmitting mesh plate is arranged above the wave-transmitting baffle, the wave-transmitting mesh plate is fixed on the inner wall of the inner cavity of the cylindrical cavity, and both the wave-transmitting mesh plate and the wave-transmitting baffle are arranged horizontally.

The microwave source or the cylindrical cavity is provided with a microwave protection air inlet for ventilating or pressurizing the microwave feeding area.

The cylindrical cavity is provided with a microwave protection air outlet, the microwave protection air outlet is located in the microwave feeding area, and an air outlet regulating valve is connected to the microwave protection air outlet.

The igniter is a high frequency plasma torch or a chemical flame torch or a microwave plasma torch.

The taper of the conical cavity is 0.001:1-1000:1.

The working principle of the present invention is as follows:

In the prior art, it is difficult for a microwave device with low microwave power density to form plasma, the plasma is easy to drift and drift, the microwave feed port is likely to break down, and the plasma cannot be kept stable. The microwave plasma torch in the form of jet is excited and exists in the same high microwave power density region, the temperature is high, a large amount of auxiliary gas needs to be introduced for confinement orientation, the reaction rate of the introduced gas is low, the power is low, and it is difficult to industrialize application. Compared with the above two, the microwave plasma of the present invention can stably exist in the reaction cavity with relatively low microwave power density.

After the invention uniquely adopts the reaction cavity structure with the conical cavity, it does not have much influence on the microwave power density distribution in the reaction cavity, and effectively combines the microwave principle with the buoyancy principle of the fluid under the condition of temperature difference and its buoyancy principle. The laws of motion are organically combined. Even if a small plasma is formed under the condition of low microwave power density, it will be carried out under the action of buoyancy due to the temperature rise and the change of density, without the need to introduce a high-speed jet of auxiliary gas. Constraint control, it can drift upward and converge on the top of the conical cavity without moving around, so that the temperature conditions for the existence of plasma can be maintained, and it will not drift and extinguish.

More importantly, due to the structure of the conical cavity with a small upper part and a large lower part, it can maintain the plasma concentration without restricting the volume of the plasma to change, and can allow the plasma to expand freely with the increase of the input microwave power density. A large volume of plasma is obtained; although the volume of the plasma gathered in the conical cavity will increase with the increase of the microwave power density, the projected area of the conical space occupied by the plasma expands by the square of the corresponding diameter, so the plasma is in the conical cavity. The expansion in the vertical direction is small, as long as the size of the conical cavity matches the total input microwave power, that is, it is large enough, the plasma will not drift into the cylindrical cavity of the reaction cavity; The inner microwave power density is lower and cannot provide enough electric field strength for the plasma to exist in this region. Based on this, the device structure of the present invention can simply and effectively control the stable existence of plasma without adding auxiliary gas jets to confine the plasma, and does not diffuse to the microwave feeding area and the microwave feeding port, and will not cause damage to ensure the long-term stable operation of the device.

At the same time, since the plasma is effectively controlled in the conical cavity and has a good absorption effect on microwaves, it can be loaded by the microwaves as a whole and uniformly, and flows at a low speed, so the plasma temperature is relatively uniform. It is known that the temperature difference in different regions is within ±50°C of the average temperature; in addition, since no auxiliary gas is required to confine the plasma, there will not be a large amount of low-temperature gas surrounding the plasma, and only the part of the plasma that contacts the cavity wall or the thermal insulation layer The temperature is low, but the temperature will not be too low due to the effect of heat preservation, and from the cross section of the conical cavity, it is only a very thin annular area, accounting for less than 5%; therefore, the proportion of plasma in the area where plasma exists as high as 95% or more.

The beneficial effects of the present invention are mainly manifested in the following aspects:

1. In the present invention, a gas channel I and a gas channel II are opened on the reaction cavity, the reaction cavity includes a cylindrical cavity and a conical cavity located above the cylindrical cavity, the conical cavity is communicated with the cylindrical cavity, and the cylindrical cavity is connected to the cylindrical cavity. There is a microwave feed port, the microwave source is connected to the microwave feed port, and the igniter is connected to the conical cavity. Through the unique reaction cavity structure with a conical cavity, the microwave principle is effectively combined with the buoyancy of the fluid under the condition of temperature difference. The principle and its motion law are organically combined. Even after a small volume of plasma is formed under the condition of low microwave power density, due to the temperature rise and the change of density, there is no need to enter the auxiliary under the action of buoyancy. The high-speed jet of gas is constrained and controlled to drift upward and converge on the top of the conical cavity without moving around, so that the temperature conditions for the existence of the plasma can be maintained, and it will not drift and extinguish; more importantly, because of the conical cavity The structure with a small top and a large bottom can keep the plasma converged without restricting the volume of the plasma to change. With the increase of the input microwave power density, the plasma can expand freely, so that a large-volume plasma can be obtained. ; Although the volume of the plasma gathered in the conical cavity will increase with the increase of the microwave power density, the projected area of the conical space occupied by the plasma expands by the square of the corresponding diameter, so the expansion of the plasma in the vertical direction is small, as long as The size of the conical cavity matches the total input microwave power, that is, the conical cavity is large enough so that the plasma will not drift into the cylindrical cavity of the reaction cavity; furthermore, the microwave power density in the cylindrical cavity of the reaction cavity is higher. low, it cannot provide enough electric field strength for plasma to exist in this area. Based on this, the device structure of the present invention can simply and effectively control the stable existence of plasma without adding auxiliary gas jets to confine the plasma, and does not diffuse to the microwave feeding area and the microwave feeding port, and will not cause damage to ensure the long-term stable operation of the device. The gas to be processed can pass through the gas channel I and be discharged from the gas channel II, or be passed through the gas channel II and discharged from the gas channel I, so that the gas to be treated can pass through the plasma area in the reaction chamber at a low speed and uniformly. There are three technical means, namely: First, when the structure of the reaction chamber, especially the conical chamber, remains unchanged, and the input microwave power remains unchanged, adjust the flow rate of the gas to be processed through the plasma area, and increase the flow rate to make The plasma volume increases and the temperature decreases. Reducing the flow rate can reduce the plasma volume and increase the temperature. Second, when the structure of the reaction chamber and the taper of the conical chamber remain unchanged, and the flow rate of the gas to be treated remains unchanged, adjust Input the microwave power. Increasing the microwave power can increase the plasma volume and increase the temperature. Decreasing the microwave power can reduce the plasma volume and reduce the temperature. Tapered conical cavity, reducing the taper can reduce the amplitude and speed of plasma volume increase and decrease when the input microwave power changes, and increase the plasma temperature increase and decrease amplitude and speed, and increase the taper when the input microwave power changes. Plasma volume increase and decrease amplitude and speed, decrease plasma temperature increase and decrease amplitude and speed. In addition, the above three technical means can be comprehensively used to adjust the flow rate of gas passing through the plasma area, adjust the input microwave power, and change the taper of the conical cavity. Combined with the needs of the processing materials, the plasma volume can be adjusted conveniently and effectively. and temperature to meet practical application needs. In addition, because the conical cavity is different from the jet microwave plasma torch, it is a system with low microwave power density and is not limited by the microwave transmission system. According to the maximum input microwave power, the conical cavity can be enlarged and lengthened, or the conical cavity can be shortened and shortened. The cavity can form a single large-volume microwave plasma device with microwave power of 1kW-1000kW or even greater. Compared with the prior art, it can achieve sufficient and uniform heating of the gas to be treated, improve the reaction efficiency, and form a large and uniform thermal plasma, which can effectively prevent the generation of destructive breakdown discharge and ensure long-term stable operation of the entire generator. sex. Therefore, the device of the present invention not only has abundant adjustment means, is easy to control, and is easy to engineer, but also can meet the needs of large-scale industrial production.

2. In the present invention, the reaction cavity is a double-layer metal structure, including an inner cavity and an outer cavity, and an interlayer for introducing a fluid medium is formed between the inner cavity and the outer cavity. The gas or liquid that does not react in the reaction chamber, such as air, nitrogen, water, and heat transfer oil, can be used to achieve constant temperature regulation, that is, when the temperature is low, the flow rate of the gas or liquid is zero, which can play a role of heat preservation, and when the temperature is high, increase the gas Or liquid flow, can play a role in heat dissipation, which can effectively prevent the metal temperature of the cavity wall from being too high and lose its strength, and can manufacture large-scale high-power devices to meet the needs of large-scale industrial production.

3. In the present invention, the inner wall of the inner cavity of the conical cavity is lined with a thermal insulation layer, and the thickness of the thermal insulation layer is 5-200 mm. The selection of this specific thickness of the thermal insulation layer is mainly to reduce the plasma energy consumption. At the same time, small plasma devices that meet the requirements of lower power can use thinner thermal insulation layers to reduce the volume of the device, improve integration, and improve startup convenience; and large-scale plasma devices that meet the requirements of higher power can use larger It can greatly reduce the speed of heat conduction to the outside, reduce the energy that needs to be taken away by heat dissipation, reduce the flow rate of the fluid into the double-layer metal structure of the reaction chamber, and make it easier to control the temperature of the reaction chamber. ; So as to reduce the heat dissipation of the system as much as possible, it can effectively prevent the metal temperature of the inner cavity from being too high and lose its strength. At the same time, since the metal strength is guaranteed, the strength and sealing performance of the entire reaction chamber can be effectively guaranteed, so that the generator of the present invention can be safely applied to high temperature treatment, inflammable and explosive material treatment, toxic and harmful material treatment, chemical industry production, has a wide range of application prospects.

Fourth, in the present invention, the thermal insulation layer is an aluminum oxide thermal insulation layer, a zirconia thermal insulation layer, a silicon oxide thermal insulation layer, a silicon thermal insulation layer, a graphite thermal insulation layer, a silicon nitride thermal insulation layer, and a carbon nitride thermal insulation layer Or boron nitride thermal insulation layer, these thermal insulation materials are not only resistant to high temperature, but also maintain good physical and chemical stability under high temperature conditions, and will not crack, fall off, decompose, and will not produce gas to be treated. pollution, thereby reducing the post-processing process and production costs.

5. In the present invention, a wave-transmitting baffle is fixedly connected in the cylindrical cavity, the wave-transmitting baffle and the cylindrical cavity form a microwave feeding area, and the microwave feeding port is located in the microwave feeding area. The relatively sealed microwave feeding area can effectively prevent the plasma from diffusing into the microwave feeding area, thereby preventing the plasma from causing destructive breakdown discharge near the microwave feeding port.

6. In the present invention, a wave-transmitting mesh plate is arranged above the wave-transmitting baffle, the wave-transmitting mesh plate is fixed on the inner wall of the inner cavity of the cylindrical cavity, and the wave-transmitting mesh plate and the wave-transmitting baffle are arranged horizontally. , when the gas to be treated is passed in from the gas channel I and discharged from the gas channel II, the incoming gas to be treated can be uniformly dispersed and continue to move upward at a relatively low flow rate; due to the low flow rate to be treated, it can be uniformly Into the plasma area, and will not produce large disturbance to the plasma, which can ensure the stability of the plasma to be treated gas.

7. In the present invention, the microwave source or the cylindrical cavity is provided with a microwave protection air inlet for ventilating or pressurizing the microwave feeding area, and gas is introduced into the microwave feeding area through the microwave protection air inlet. The microwave feeding area can be cooled to prevent the influence of plasma and thermal radiation on the microwave feeding area, ensuring that the gas breakdown strength in the microwave feeding area is high, thereby ensuring that no destructive breakdown discharge occurs, and ensuring that the microwave continues stable input.

8. In the present invention, a microwave protection gas outlet is opened on the cylindrical cavity, the microwave protection gas outlet is located in the microwave feeding area, and a gas outlet regulating valve is connected to the microwave protection gas outlet. When the gas is discharged from the microwave protection gas outlet, it is adjusted or Closing the gas outlet regulating valve of the microwave protection gas outlet can increase the gas pressure in the microwave feeding zone, thereby further improving the breakdown strength of the microwave feeding zone.

9. In the present invention, the taper of the conical cavity is 0.001:1-1000:1, which can meet the needs of replacing conical cavities with different tapers under the condition that the flow rate of the gas to be treated remains unchanged. When changing, reduce the amplitude and speed of increase and decrease of plasma volume, increase the amplitude and speed of increase and decrease of plasma temperature, and increase the taper to increase the amplitude and speed of increase and decrease of plasma volume and reduce plasma temperature when the input microwave power changes. The increase or decrease range and speed can increase the control means for the plasma to meet the needs of practical applications.

Description of drawings

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments of the description, wherein:

Fig. 1 is the structural representation of the present invention;

2 is a schematic structural diagram of Embodiment 5 of the present invention;

Labels in the figure: 1, igniter, 2, conical cavity, 3, microwave source, 4, microwave feed port, 5, gas channel I, 6, gas channel II, 7, cylindrical cavity, 8, inner cavity, 9. Outer cavity, 10, interlayer, 11, heat insulation layer, 12, wave-transmitting baffle, 13, wave-transmitting mesh plate, 14, microwave protection air inlet, 15, microwave protection air outlet, 16, air outlet adjustment valve.

Detailed ways

Example 1

A non-jet atmospheric thermal plasma generator includes an igniter 1 and a microwave source 3, and also includes a reaction cavity, the reaction cavity is provided with a gas channel I5 and a gas channel II6, and the reaction cavity includes a cylindrical cavity 7 and the conical cavity 2 located above the cylindrical cavity 7, the conical cavity 2 is communicated with the cylindrical cavity 7, the cylindrical cavity 7 is provided with a microwave feed port 4, and the microwave source 3 is connected to the microwave feed port 4 , the igniter 1 is connected to the conical cavity 2 .

This embodiment is the most basic implementation. The reaction chamber is provided with a gas channel I and a gas channel II. The reaction chamber includes a cylindrical cavity and a conical cavity located above the cylindrical cavity. The conical cavity is communicated with the cylindrical cavity. , there is a microwave feed port on the cylindrical cavity, the microwave source is connected with the microwave feed port, and the igniter is connected with the conical cavity. The buoyancy principle of the fluid and its motion law under the condition are organically combined. Even after the formation of a small volume of plasma under the condition of low microwave power density, the effect of buoyancy will be affected by the temperature rise and the change of density. It can drift upward and converge at the top of the conical cavity without the need to introduce a high-speed jet of auxiliary gas for confinement control without moving around, so that the temperature conditions for the existence of the plasma can be maintained, and it will not drift and extinguish; more importantly It is due to the structure of the conical cavity that the upper part is small and the lower part is large, which can keep the plasma convergence without restricting the volume of the plasma to change, and can allow the plasma to expand freely with the increase of the input microwave power density. Large-volume plasma; although the volume of the plasma gathered in the conical cavity will increase with the increase of the microwave power density, the projected area of the conical space occupied by the plasma expands by the square times of the corresponding diameter. The expansion is small, as long as the size of the conical cavity matches the total input microwave power, that is, the conical cavity is large enough, the plasma will not drift into the cylindrical cavity of the reaction cavity; The inner microwave power density is lower and cannot provide enough electric field strength for the plasma to exist in this region. Based on this, the device structure of the present invention can simply and effectively control the stable existence of plasma without adding auxiliary gas jets to confine the plasma, and does not diffuse to the microwave feeding area and the microwave feeding port, and will not cause damage to ensure the long-term stable operation of the device. The gas to be processed can pass through the gas channel I and be discharged from the gas channel II, or be passed through the gas channel II and discharged from the gas channel I, so that the gas to be treated can pass through the plasma area in the reaction chamber at a low speed and uniformly. There are three technical means, namely: First, when the structure of the reaction chamber, especially the conical chamber, remains unchanged, and the input microwave power remains unchanged, adjust the flow rate of the gas to be processed through the plasma area, and increase the flow rate to make The plasma volume increases and the temperature decreases. Reducing the flow rate can reduce the plasma volume and increase the temperature. Second, when the structure of the reaction chamber and the taper of the conical chamber remain unchanged, and the flow rate of the gas to be treated remains unchanged, adjust Input the microwave power. Increasing the microwave power can increase the plasma volume and increase the temperature. Decreasing the microwave power can reduce the plasma volume and reduce the temperature. Tapered conical cavity, reducing the taper can reduce the amplitude and speed of plasma volume increase and decrease when the input microwave power changes, and increase the plasma temperature increase and decrease amplitude and speed, and increase the taper when the input microwave power changes. Plasma volume increase and decrease amplitude and speed, decrease plasma temperature increase and decrease amplitude and speed. In addition, the above three technical means can be comprehensively used to adjust the flow rate of gas passing through the plasma area, adjust the input microwave power, and change the taper of the conical cavity. Combined with the needs of the processing materials, the plasma volume can be adjusted conveniently and effectively. and temperature to meet practical application needs. In addition, because the conical cavity is different from the jet microwave plasma torch, it is a system with low microwave power density and is not limited by the microwave transmission system. According to the maximum input microwave power, the conical cavity can be enlarged and lengthened, or the conical cavity can be shortened and shortened. The cavity can form a single large-volume microwave plasma device with microwave power of 1kW-1000kW or even greater. Compared with the prior art, it can achieve sufficient and uniform heating of the gas to be treated, improve the reaction efficiency, and form a large and uniform thermal plasma, which can effectively prevent the generation of destructive breakdown discharge and ensure long-term stable operation of the entire generator. sex. Therefore, the device of the present invention not only has abundant adjustment means, is easy to control, and is easy to engineer, but also can meet the needs of large-scale industrial production.

Example 2

A non-jet atmospheric thermal plasma generator includes an igniter 1 and a microwave source 3, and also includes a reaction cavity, the reaction cavity is provided with a gas channel I5 and a gas channel II6, and the reaction cavity includes a cylindrical cavity 7 and the conical cavity 2 located above the cylindrical cavity 7, the conical cavity 2 is communicated with the cylindrical cavity 7, the cylindrical cavity 7 is provided with a microwave feed port 4, and the microwave source 3 is connected to the microwave feed port 4 , the igniter 1 is connected to the conical cavity 2 .

The reaction chamber is a double-layer metal structure, including an inner chamber 8 and an outer chamber 9, and an interlayer 10 for passing a fluid medium is formed between the inner chamber 8 and the outer chamber 9.

The inner wall of the inner cavity 8 of the conical cavity 2 is lined with a thermal insulation layer 11, and the thickness of the thermal insulation layer 11 is 5 mm.

The heat insulating layer 11 is an alumina heat insulating layer.

This embodiment is a preferred implementation, and the reaction chamber is a double-layer metal structure, including an inner chamber and an outer chamber, and a sandwich for the passage of fluid medium is formed between the inner chamber and the outer chamber, and can be directed to the inner chamber and the outer chamber. The gas or liquid that does not react with the reaction chamber, such as air, nitrogen, water, and heat-conducting oil, is introduced into the interlayer to achieve constant temperature regulation, that is, when the temperature is low, the flow rate of the gas or liquid is zero, which can play a role in heat preservation. Increasing the flow of gas or liquid at high temperature can play a role in heat dissipation, which can effectively prevent the metal temperature of the cavity wall from being too high and lose its strength, and can manufacture large-scale high-power devices to meet the needs of large-scale industrial production.

The inner wall of the inner cavity of the conical cavity is lined with a thermal insulation layer, and the thickness of the thermal insulation layer is 5 mm. Small and small plasma devices can use thinner thermal insulation layers to reduce device volume, improve integration, and improve startup convenience; and large-scale plasma devices that meet the needs of higher power can use larger thicknesses to greatly reduce heat. The speed of outward conduction reduces the energy that needs to be taken away by heat dissipation, reduces the flow of fluid into the double-layer metal structure of the reaction chamber, and makes it easier to control the temperature of the reaction chamber; At the same time of heat dissipation, it can effectively prevent the metal temperature of the inner cavity from being too high and lose its strength. At the same time, since the metal strength is guaranteed, the strength and sealing performance of the entire reaction chamber can be effectively guaranteed, so that the generator of the present invention can be safely applied to high temperature treatment, inflammable and explosive material treatment, toxic and harmful material treatment, chemical industry production, has a wide range of application prospects.

Example 3

A non-jet atmospheric thermal plasma generator includes an igniter 1 and a microwave source 3, and also includes a reaction cavity, the reaction cavity is provided with a gas channel I5 and a gas channel II6, and the reaction cavity includes a cylindrical cavity 7 and the conical cavity 2 located above the cylindrical cavity 7, the conical cavity 2 is communicated with the cylindrical cavity 7, the cylindrical cavity 7 is provided with a microwave feed port 4, and the microwave source 3 is connected to the microwave feed port 4 , the igniter 1 is connected to the conical cavity 2 .

The reaction chamber is a double-layer metal structure, including an inner chamber 8 and an outer chamber 9, and an interlayer 10 for passing a fluid medium is formed between the inner chamber 8 and the outer chamber 9.

The inner wall of the inner cavity 8 of the conical cavity 2 is lined with a thermal insulation layer 11, and the thickness of the thermal insulation layer 11 is 60 mm.

The heat insulating layer 11 is a zirconia heat insulating layer.

A wave-transmitting baffle 12 is fixedly connected in the cylindrical cavity 7 , the wave-transmitting baffle 12 and the cylindrical cavity 7 form a microwave feeding area, and the microwave feeding port 4 is located in the microwave feeding area.

This embodiment is another preferred implementation. A wave-transmitting baffle is fixedly connected to the cylindrical cavity. The wave-transmitting baffle and the cylindrical cavity form a microwave feeding area. The microwave feeding port is located in the microwave feeding area. The wave baffle isolates a relatively sealed microwave feeding area, which can effectively prevent the plasma from diffusing into the microwave feeding area, thereby preventing the plasma from causing destructive breakdown discharge near the microwave feeding port.

Example 4

A non-jet atmospheric thermal plasma generator includes an igniter 1 and a microwave source 3, and also includes a reaction cavity, the reaction cavity is provided with a gas channel I5 and a gas channel II6, and the reaction cavity includes a cylindrical cavity 7 and the conical cavity 2 located above the cylindrical cavity 7, the conical cavity 2 is communicated with the cylindrical cavity 7, the cylindrical cavity 7 is provided with a microwave feed port 4, and the microwave source 3 is connected to the microwave feed port 4 , the igniter 1 is connected to the conical cavity 2 .

The reaction chamber is a double-layer metal structure, including an inner chamber 8 and an outer chamber 9, and an interlayer 10 for passing a fluid medium is formed between the inner chamber 8 and the outer chamber 9.

The inner wall of the inner cavity 8 of the conical cavity 2 is lined with a thermal insulation layer 11, and the thickness of the thermal insulation layer 11 is 120 mm.

The heat insulating layer 11 is a silicon oxide heat insulating layer.

A wave-transmitting baffle 12 is fixedly connected in the cylindrical cavity 7 , the wave-transmitting baffle 12 and the cylindrical cavity 7 form a microwave feeding area, and the microwave feeding port 4 is located in the microwave feeding area.

A wave-transmitting mesh plate 13 is arranged above the wave-transmitting baffle plate 12 , and the wave-transmitting mesh plate 13 is fixed on the inner wall of the inner cavity 8 of the cylindrical cavity 7 . The wave-transmitting mesh plate 13 and the wave-transmitting baffle plate 12 All are arranged horizontally.

The microwave source 3 is provided with a microwave protection air inlet 14 for ventilating or pressurizing the microwave feeding area.

This embodiment is another preferred implementation. A wave-transmitting mesh plate is arranged above the wave-transmitting baffle, and the wave-transmitting mesh plate is fixed on the inner wall of the inner cavity of the cylindrical cavity. The baffles are arranged horizontally. When the gas to be treated is introduced from the gas channel I and discharged from the gas channel II, the incoming gas to be treated can be dispersed evenly and continue to move upward at a relatively low flow rate; due to the flow rate of the to-be-treated gas It can enter the plasma area uniformly, and it will not cause great disturbance to the plasma, and can ensure the stability of the plasma of the gas to be treated.

Example 5

A non-jet atmospheric thermal plasma generator includes an igniter 1 and a microwave source 3, and also includes a reaction cavity, the reaction cavity is provided with a gas channel I5 and a gas channel II6, and the reaction cavity includes a cylindrical cavity 7 and the conical cavity 2 located above the cylindrical cavity 7, the conical cavity 2 is communicated with the cylindrical cavity 7, the cylindrical cavity 7 is provided with a microwave feed port 4, and the microwave source 3 is connected to the microwave feed port 4 , the igniter 1 is connected to the conical cavity 2 .

The reaction chamber is a double-layer metal structure, including an inner chamber 8 and an outer chamber 9, and an interlayer 10 for passing a fluid medium is formed between the inner chamber 8 and the outer chamber 9.

The inner wall of the inner cavity 8 of the conical cavity 2 is lined with a thermal insulation layer 11, and the thickness of the thermal insulation layer 11 is 200 mm.

The heat insulating layer 11 is a silicon heat insulating layer.

A wave-transmitting baffle 12 is fixedly connected in the cylindrical cavity 7 , the wave-transmitting baffle 12 and the cylindrical cavity 7 form a microwave feeding area, and the microwave feeding port 4 is located in the microwave feeding area.

A wave-transmitting mesh plate 13 is arranged above the wave-transmitting baffle plate 12 , and the wave-transmitting mesh plate 13 is fixed on the inner wall of the inner cavity 8 of the cylindrical cavity 7 . The wave-transmitting mesh plate 13 and the wave-transmitting baffle plate 12 All are arranged horizontally.

The cylindrical cavity 7 is provided with a microwave protection air inlet 14 for ventilating or pressurizing the microwave feeding area.

The cylindrical cavity 7 is provided with a microwave protection gas outlet 15 , the microwave protection gas outlet 15 is located in the microwave feeding area, and the microwave protection gas outlet 15 is connected with a gas outlet regulating valve 16 .

The igniter 1 is a high frequency plasma torch.

The taper of the conical cavity 2 is 0.001:1.

This embodiment is another preferred implementation.

Example 6

A non-jet atmospheric thermal plasma generator includes an igniter 1 and a microwave source 3, and also includes a reaction cavity, the reaction cavity is provided with a gas channel I5 and a gas channel II6, and the reaction cavity includes a cylindrical cavity 7 and the conical cavity 2 located above the cylindrical cavity 7, the conical cavity 2 is communicated with the cylindrical cavity 7, the cylindrical cavity 7 is provided with a microwave feed port 4, and the microwave source 3 is connected to the microwave feed port 4 , the igniter 1 is connected to the conical cavity 2 .

The reaction chamber is a double-layer metal structure, including an inner chamber 8 and an outer chamber 9, and an interlayer 10 for passing a fluid medium is formed between the inner chamber 8 and the outer chamber 9.

The inner wall of the inner cavity 8 of the conical cavity 2 is lined with a thermal insulation layer 11, and the thickness of the thermal insulation layer 11 is 200 mm.

The heat insulating layer 11 is a graphite heat insulating layer.

A wave-transmitting baffle 12 is fixedly connected in the cylindrical cavity 7 , the wave-transmitting baffle 12 and the cylindrical cavity 7 form a microwave feeding area, and the microwave feeding port 4 is located in the microwave feeding area.

A wave-transmitting mesh plate 13 is arranged above the wave-transmitting baffle plate 12 , and the wave-transmitting mesh plate 13 is fixed on the inner wall of the inner cavity 8 of the cylindrical cavity 7 . The wave-transmitting mesh plate 13 and the wave-transmitting baffle plate 12 All are arranged horizontally.

The cylindrical cavity 7 is provided with a microwave protection air inlet 14 for ventilating or pressurizing the microwave feeding area.

The cylindrical cavity 7 is provided with a microwave protection gas outlet 15 , the microwave protection gas outlet 15 is located in the microwave feeding area, and the microwave protection gas outlet 15 is connected with a gas outlet regulating valve 16 .

The igniter 1 is a chemical flame torch.

The taper of the conical cavity 2 is 0.01:1.

This embodiment is another preferred implementation.

Example 7

A non-jet atmospheric thermal plasma generator includes an igniter 1 and a microwave source 3, and also includes a reaction cavity, the reaction cavity is provided with a gas channel I5 and a gas channel II6, and the reaction cavity includes a cylindrical cavity 7 and the conical cavity 2 located above the cylindrical cavity 7, the conical cavity 2 is communicated with the cylindrical cavity 7, the cylindrical cavity 7 is provided with a microwave feed port 4, and the microwave source 3 is connected to the microwave feed port 4 , the igniter 1 is connected to the conical cavity 2 .

The reaction chamber is a double-layer metal structure, including an inner chamber 8 and an outer chamber 9, and an interlayer 10 for passing a fluid medium is formed between the inner chamber 8 and the outer chamber 9.

The inner wall of the inner cavity 8 of the conical cavity 2 is lined with a thermal insulation layer 11, and the thickness of the thermal insulation layer 11 is 200 mm.

The heat insulating layer 11 is a silicon nitride heat insulating layer.

A wave-transmitting baffle 12 is fixedly connected in the cylindrical cavity 7 , the wave-transmitting baffle 12 and the cylindrical cavity 7 form a microwave feeding area, and the microwave feeding port 4 is located in the microwave feeding area.

A wave-transmitting mesh plate 13 is arranged above the wave-transmitting baffle plate 12 , and the wave-transmitting mesh plate 13 is fixed on the inner wall of the inner cavity 8 of the cylindrical cavity 7 . The wave-transmitting mesh plate 13 and the wave-transmitting baffle plate 12 All are arranged horizontally.

The cylindrical cavity 7 is provided with a microwave protection air inlet 14 for ventilating or pressurizing the microwave feeding area.

The cylindrical cavity 7 is provided with a microwave protection gas outlet 15 , the microwave protection gas outlet 15 is located in the microwave feeding area, and the microwave protection gas outlet 15 is connected with a gas outlet regulating valve 16 .

The igniter 1 is a microwave plasma torch.

The taper of the conical cavity 2 is 100:1.

This embodiment is another preferred implementation.

Example 8

A non-jet atmospheric thermal plasma generator includes an igniter 1 and a microwave source 3, and also includes a reaction cavity, the reaction cavity is provided with a gas channel I5 and a gas channel II6, and the reaction cavity includes a cylindrical cavity 7 and the conical cavity 2 located above the cylindrical cavity 7, the conical cavity 2 is communicated with the cylindrical cavity 7, the cylindrical cavity 7 is provided with a microwave feed port 4, and the microwave source 3 is connected to the microwave feed port 4 , the igniter 1 is connected to the conical cavity 2 .

The reaction chamber is a double-layer metal structure, including an inner chamber 8 and an outer chamber 9, and an interlayer 10 for passing a fluid medium is formed between the inner chamber 8 and the outer chamber 9.

The inner wall of the inner cavity 8 of the conical cavity 2 is lined with a thermal insulation layer 11, and the thickness of the thermal insulation layer 11 is 200 mm.

The heat insulating layer 11 is a carbon nitride heat insulating layer.

A wave-transmitting baffle 12 is fixedly connected in the cylindrical cavity 7 , the wave-transmitting baffle 12 and the cylindrical cavity 7 form a microwave feeding area, and the microwave feeding port 4 is located in the microwave feeding area.

A wave-transmitting mesh plate 13 is arranged above the wave-transmitting baffle plate 12 , and the wave-transmitting mesh plate 13 is fixed on the inner wall of the inner cavity 8 of the cylindrical cavity 7 . The wave-transmitting mesh plate 13 and the wave-transmitting baffle plate 12 All are arranged horizontally.

The cylindrical cavity 7 is provided with a microwave protection air inlet 14 for ventilating or pressurizing the microwave feeding area.

The cylindrical cavity 7 is provided with a microwave protection gas outlet 15 , the microwave protection gas outlet 15 is located in the microwave feeding area, and the microwave protection gas outlet 15 is connected with a gas outlet regulating valve 16 .

The igniter 1 is a microwave plasma torch.

The taper of the conical cavity 2 is 600:1.

This embodiment is another preferred implementation.

Example 9

A non-jet atmospheric thermal plasma generator includes an igniter 1 and a microwave source 3, and also includes a reaction cavity, the reaction cavity is provided with a gas channel I5 and a gas channel II6, and the reaction cavity includes a cylindrical cavity 7 and the conical cavity 2 located above the cylindrical cavity 7, the conical cavity 2 is communicated with the cylindrical cavity 7, the cylindrical cavity 7 is provided with a microwave feed port 4, and the microwave source 3 is connected to the microwave feed port 4 , the igniter 1 is connected to the conical cavity 2 .

The reaction chamber is a double-layer metal structure, including an inner chamber 8 and an outer chamber 9, and an interlayer 10 for passing a fluid medium is formed between the inner chamber 8 and the outer chamber 9.

The inner wall of the inner cavity 8 of the conical cavity 2 is lined with a thermal insulation layer 11, and the thickness of the thermal insulation layer 11 is 200 mm.

The heat insulating layer 11 is a boron nitride heat insulating layer.

A wave-transmitting baffle 12 is fixedly connected in the cylindrical cavity 7 , the wave-transmitting baffle 12 and the cylindrical cavity 7 form a microwave feeding area, and the microwave feeding port 4 is located in the microwave feeding area.

A wave-transmitting mesh plate 13 is arranged above the wave-transmitting baffle plate 12 , and the wave-transmitting mesh plate 13 is fixed on the inner wall of the inner cavity 8 of the cylindrical cavity 7 . The wave-transmitting mesh plate 13 and the wave-transmitting baffle plate 12 All are arranged horizontally.

The cylindrical cavity 7 is provided with a microwave protection air inlet 14 for ventilating or pressurizing the microwave feeding area.

The cylindrical cavity 7 is provided with a microwave protection gas outlet 15 , the microwave protection gas outlet 15 is located in the microwave feeding area, and the microwave protection gas outlet 15 is connected with a gas outlet regulating valve 16 .

The igniter 1 is a high frequency plasma torch or a chemical flame torch or a microwave plasma torch.

The taper of the conical cavity 2 is 1000:1.

This embodiment is the best implementation. The reaction chamber is provided with a gas channel I and a gas channel II. The reaction chamber includes a cylindrical cavity and a conical cavity above the cylindrical cavity. The conical cavity is communicated with the cylindrical cavity. There is a microwave feed port on the cylindrical cavity, the microwave source is connected to the microwave feed port, and the igniter is connected to the conical cavity. Through the unique reaction cavity structure with a conical cavity, the microwave principle and temperature difference conditions are effectively The buoyancy principle of the lower fluid and its motion law are organically combined. Even after a small volume of plasma is formed under the condition of low microwave power density, due to the temperature rise and the change of density, under the action of buoyancy It can drift upward and converge at the top of the conical cavity without the need to introduce a high-speed jet of auxiliary gas for constraining control, without moving around, so that the temperature conditions for the existence of the plasma can be maintained, and it will not drift and extinguish; more importantly, Due to the structure of the conical cavity with a small upper part and a large lower part, it can keep the plasma convergence without restricting the volume of the plasma to change, and can allow the plasma to expand freely with the increase of the input microwave power density. volume of plasma; although the volume of plasma gathered in the conical cavity will increase with the increase of the microwave power density, the projected area of the conical space occupied by the plasma expands by the square of the corresponding diameter, so the expansion of the plasma in the vertical direction is smaller, as long as the size of the conical cavity matches the total input microwave power, that is, the conical cavity is large enough, the plasma will not drift into the cylindrical cavity of the reaction cavity; The microwave power density is lower and cannot provide enough electric field strength for the plasma to exist in this area. Based on this, the device structure of the present invention can simply and effectively control the stable existence of plasma without adding auxiliary gas jets to confine the plasma, and does not diffuse to the microwave feeding area and the microwave feeding port, and will not cause damage to ensure the long-term stable operation of the device. The gas to be treated can pass through the plasma area in the reaction chamber at a low speed and uniformly through the gas passage I and the gas passage II discharge, or the gas passage II and the gas passage I discharge. There are three technical means, namely: First, when the structure of the reaction cavity, especially the conical cavity, remains unchanged, and the input microwave power remains unchanged, adjust the flow rate of the gas to be processed through the plasma area, and increase the flow rate to make The plasma volume increases and the temperature decreases, and reducing the flow rate can reduce the plasma volume and increase the temperature; secondly, when the structure of the reaction chamber and the taper of the conical chamber remain unchanged, and the flow rate of the gas to be treated remains unchanged, adjust Input the microwave power. Increasing the microwave power can increase the plasma volume and increase the temperature. Decreasing the microwave power can reduce the plasma volume and reduce the temperature. Tapered conical cavity, reducing the taper can reduce the amplitude and speed of plasma volume increase and decrease when the input microwave power changes, and increase the amplitude and speed of the plasma temperature increase and decrease, increasing the taper can increase when the input microwave power changes. Plasma volume increase and decrease amplitude and speed, decrease plasma temperature increase and decrease amplitude and speed. In addition, the above three technical means can be comprehensively used to adjust the flow rate of gas passing through the plasma area, adjust the input microwave power, and change the taper of the conical cavity. Combined with the needs of the processing materials, the plasma volume can be adjusted conveniently and effectively. and temperature to meet practical application needs. In addition, because the conical cavity is different from the jet microwave plasma torch, it is a system with low microwave power density and is not limited by the microwave transmission system. According to the maximum input microwave power, the conical cavity can be enlarged and lengthened, or the conical cavity can be shortened and shortened. The cavity can form a single large-volume microwave plasma device with a microwave power of 1kW-1000kW or even greater. Compared with the prior art, it can achieve sufficient and uniform heating of the gas to be treated, improve the reaction efficiency, and form a large and uniform thermal plasma, which can effectively prevent the generation of destructive breakdown discharge and ensure long-term stable operation of the entire generator. sex. Therefore, the device of the present invention not only has abundant adjustment means, is easy to control, and is easy to engineer, but also can meet the needs of large-scale industrial production.

There is a microwave protection gas outlet on the cylindrical cavity, the microwave protection gas outlet is located in the microwave feeding area, and a gas outlet regulating valve is connected to the microwave protection gas outlet. When the gas is discharged from the microwave protection gas outlet, the microwave protection gas outlet is adjusted or closed. The gas outlet regulating valve can increase the gas pressure in the microwave feeding zone, thereby further improving the breakdown strength of the microwave feeding zone.

Claims (10)

1. A non-jet atmospheric pressure thermal plasma generator, comprising an igniter (1) and a microwave source (3), characterized in that: also comprising a reaction cavity on which a gas channel I (5 ) and gas channel II (6), the reaction chamber includes a cylindrical cavity (7) and a conical cavity (2) located above the cylindrical cavity (7), the conical cavity (2) and the cylindrical cavity (7) ), the cylindrical cavity (7) is provided with a microwave feed port (4), the microwave source (3) is connected to the microwave feed port (4), and the igniter (1) is connected to the conical cavity (2) superior. 2. A non-jet atmospheric thermal plasma generator according to claim 1, characterized in that: the reaction chamber is a double-layer metal structure, comprising an inner chamber (8) and an outer chamber (9) , an interlayer (10) for introducing fluid medium is formed between the inner cavity (8) and the outer cavity (9). 3. A non-jet atmospheric thermal plasma generator according to claim 2, characterized in that: the inner wall of the inner cavity (8) of the conical cavity (2) is lined with a thermal insulation layer (11) , the thickness of the thermal insulation layer (11) is 5-200 mm. 4 . The non-jet atmospheric thermal plasma generator according to claim 3 , wherein the thermal insulation layer ( 11 ) is an aluminum oxide thermal insulation layer, a zirconia thermal insulation layer, and a silicon oxide thermal insulation layer. 5 . layer, silicon insulating layer, graphite insulating layer, silicon nitride insulating layer, carbon nitride insulating layer or boron nitride insulating layer. 5. A kind of non-jet atmospheric thermal plasma generator according to claim 1, characterized in that: a wave-transmitting baffle (12) is fixedly connected in the cylindrical cavity (7), and the wave-transmitting baffle ( 12) A microwave feeding area is formed with the cylindrical cavity (7), and the microwave feeding port (4) is located in the microwave feeding area. 6. The non-jet atmospheric hot plasma generator according to claim 5, characterized in that: a wave-transmitting mesh plate (13) is arranged above the wave-transmitting baffle (12), and the wave-transmitting mesh The orifice plate (13) is fixed on the inner wall of the inner cavity (8) of the cylindrical cavity (7), and the wave-transmitting mesh plate (13) and the wave-transmitting baffle plate (12) are arranged horizontally. 7. The non-jet atmospheric thermal plasma generator according to claim 5, wherein the microwave source (3) or the cylindrical cavity (7) is provided with a ventilating or The pressurized microwave protects the air inlet (14). 8. The non-jet normal pressure thermal plasma generator according to claim 5, wherein the cylindrical cavity (7) is provided with a microwave protection gas outlet (15), and the microwave protection gas outlet (15) ) is located in the microwave feeding area, and an air outlet regulating valve (16) is connected to the microwave protection air outlet (15). 9 . The non-jet atmospheric thermal plasma generator according to claim 1 , wherein the igniter ( 1 ) is a high-frequency plasma torch or a chemical flame torch or a microwave plasma torch. 10 . 10 . The non-jet atmospheric thermal plasma generator according to claim 1 , wherein the taper of the conical cavity ( 2 ) is 0.001:1-1000:1. 11 .

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