Plasma reaction device and plasma generator

Abstract

The invention provides a plasma reaction device and a plasma generator. The plasma reaction device comprises a reaction cavity and an upper cover, wherein the upper cover covers the reaction cavity and comprises a central opening and an air inlet connector separated from the central opening; the plasma reaction device further comprises an air cooling disc arranged below the upper cover, the air cooling disc comprises an air inlet, an air outlet and a rotary airflow channel located between the air inlet and the air outlet, cooling air enters the air inlet through the air inlet connector, and rotary airflow is formed in the rotary airflow channel and exhausted through the air outlet. And cooling the upper cover. The plasma generator is mounted at a central opening of the upper cover; and a plasma nozzle of the plasma generator extends into the reaction cavity.

Description

Technical Field

[0001] The present invention relates to the field of waste gas treatment technology, and in particular to a plasma reaction device for treating waste gas by plasma thermal oxidation in the semiconductor and photovoltaic fields of the electronics industry and a related plasma generator. Background Art

[0002] The tail gas or waste gas generated during the production process in the fields of photovoltaics and semiconductors contains harmful gases, which are usually removed by combustion. The tail gas is ignited by high-temperature plasma when entering the reaction chamber of the reactor. Scrubber plasma generators generally use nitrogen as the carrier gas for plasma. The high-temperature nitrogen plasma needs to transfer heat to the exhaust gas and oxygen in the air to carry out high-temperature oxidation reactions, resulting in the generation of a large amount of nitrogen oxides during the oxidation process. In order to reduce the temperature of nitrogen oxides, a large amount of nitrogen is added for cooling, so the combustion completeness is poor and the processing efficiency is low, which is prone to explosion and re-combustion accidents at the tail of the equipment.

[0003] In addition, the high-temperature nitrogen plasma flame temperature that meets the equipment's operating conditions can reach 3000K to 6000K. In order to ensure that the reaction chamber shell does not overheat, a cooling water chamber is usually provided on the reaction chamber cover that matches the plasma generator nozzle to cool the reaction chamber cover to prevent it from burning. The disadvantage is that the cooling water takes away the heat, and the water cooling causes the temperature of the reaction chamber cover to be too low. The water vapor in the waste gas incineration process is easy to condense on the cover, and the ash produced by the incineration and the condensed water droplets are mixed together and gradually sintered around the plasma torch nozzle, blocking the contact between the high-temperature plasma and the waste gas, reducing the processing efficiency and shortening the maintenance interval. Moreover, during use, when the plasma arc is unstable or close to the edge, it is very easy to burn the cooling water chamber, which greatly reduces the reliability of the equipment. In addition, there are many cooling water interfaces in the cooling water chamber, resulting in a relatively high risk of water leakage. This equipment is generally installed in a dust-free workshop and is very sensitive to water leakage. Summary of the invention

[0004] The purpose of the present invention is to provide a plasma reaction device and a related plasma generator that at least partially solve the above problems; the gas required by the system itself is used to cool and protect the upper cover of the reaction chamber, and the gas entering the reaction chamber is heated at the same time. Since the temperature of the upper cover of the reaction chamber cooled by air is higher than that of the upper cover cooled by water, there is basically no condensation of water vapor on the upper cover of the reaction chamber, and the ash on the upper cover is a layer of dry ash, which can be easily blown away by the wind. The phenomenon of slagging on the upper side of the reaction chamber is rare, which prolongs the maintenance cycle, and the high-temperature plasma is fully in contact with the exhaust gas, and the treatment efficiency is high.

[0005] According to one aspect of the present invention, a plasma reaction device is provided, comprising: a reaction chamber; an upper cover, the upper cover covering the reaction chamber and comprising a central opening and an air inlet connector separated from the central opening; wherein the plasma reaction device also comprises an air cooling plate arranged below the upper cover, the air cooling plate comprising an air inlet, an air outlet and a swirling airflow channel located between the air inlet and the air outlet, the air inlet is aligned with the air inlet connector, and the air outlet is aligned with the central opening, so that cooling gas enters the air inlet through the air inlet connector, forms a rotating airflow in the swirling airflow channel and is discharged through the air outlet, thereby cooling the upper cover.

[0006] In one embodiment, the air cooling plate includes a plurality of concentric circumferential channel walls of the same shape, and a portion of the swirling airflow channel is formed between two adjacent circumferential channel walls.

[0007] In one embodiment, a connecting opening is provided on each circumferential channel wall to connect the swirling airflow channels inside and outside the connecting opening, and the connecting openings of two adjacent circumferential channel walls are staggered from each other in the circumferential direction so that the cooling airflow is diverted at each connecting opening and flows to the next connecting opening in the direction of the air outlet.

[0008] In one embodiment, the communicating openings of two adjacent circumferential channel walls are staggered by 30 to 150 degrees in the circumferential direction.

[0009] In one embodiment, the communicating openings of two adjacent circumferential channel walls are circumferentially staggered and opposite to each other by 180 degrees.

[0010] In one embodiment, the circumferential channel wall is a polygonal channel wall.

[0011] In one embodiment, the circumferential channel wall is a circular channel wall.

[0012] In one embodiment, the swirling airflow channel is a continuous spiral channel.

[0013] According to another aspect of the present invention, a plasma generator is provided, which is configured to be used in conjunction with the above-mentioned plasma reaction device, comprising a cathode and an anode installed below the cathode, wherein the interior of the anode is hollow and provided with a longitudinal airflow channel, wherein the longitudinal airflow channel includes an upper section, a middle section and a lower section in sequence from the inlet to the outlet of the anode, and a primary swirl air inlet hole tangentially surrounding the plasma generator is provided on the side wall of the inlet of the anode, and a carrier gas forms a swirling airflow through the primary swirl air inlet hole and enters the longitudinal airflow channel, wherein the lower section protrudes longitudinally from the bottom transverse flange of the plasma generator, so that when the bottom transverse flange of the plasma generator is installed on the upper cover, the nozzle of the plasma generator extends into the interior of the reaction chamber, and the distance from the lower surface of the upper cover is greater than or equal to 5 mm.

[0014] In one embodiment, a secondary cyclone inlet hole tangentially surrounding the plasma generator is provided on the side wall below the arc landing point of the anode, so that the carrier gas entering from the primary cyclone inlet hole is mixed with the carrier gas entering from the secondary cyclone inlet hole.

[0015] In one embodiment, the inlet of the anode is configured to allow oxygen to flow in.

[0016] In one embodiment, a distance L between the outlet of the lower section and the lower surface of the air cooling plate is greater than or equal to 5 mm.

[0017] In the plasma reaction device of the present invention, the upper cover of the reaction chamber is cooled by an air cooling plate, which replaces the solution of the cooling water chamber in the prior art. The air flow channel in the air cooling plate adopts a swirling design, such as a concentric ring or a spiral shape, so that the cooling gas forms a vortex in the air flow channel and the upper cover is cooled step by step or progressively, which greatly reduces the possibility of dust agglomeration at the confluence of the plasma jet and the reaction chamber, and effectively ensures the processing efficiency.

[0018] In addition, the present invention provides a plasma generator with a simple structure, easy disassembly and assembly, and a small size. It is used in conjunction with a plasma reaction device, and can use, for example, pure oxygen as a plasma carrier gas. The generated plasma is 1000K to 3000K, for example, 1000K to 2000K, which is greatly reduced compared to the high-temperature nitrogen plasma of 3000K to 6000K in the prior art, so that the reaction temperature is reduced, and the safety and operating life are improved; in addition, the combustion flame with the exhaust gas has strong stability and good combustion completeness, which can greatly reduce the explosion and re-combustion accidents of the tail dust. In addition, by additionally arranging a tangential secondary swirl air inlet below the anode arc point of the plasma generator, the power supply is kept stable and the service life of the plasma generator is increased. In addition, the lower end outlet of the plasma generator is lengthened, so that the outlet position of the high-temperature plasma is far away from the opening of the reaction chamber, and the position where the high-temperature plasma reacts with the exhaust gas is moved down to a deep position inside the reaction chamber, avoiding the generation and accumulation of ash piles near the opening of the reaction chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to better understand the above and other purposes, features, advantages and functions of the present invention, reference may be made to the preferred embodiments shown in the accompanying drawings. The same reference numerals in the accompanying drawings refer to the same components. It should be understood by those skilled in the art that the accompanying drawings are intended to schematically illustrate the preferred embodiments of the present invention and have no limiting effect on the scope of the present invention, and the components in the drawings are not drawn to scale.

[0020] Figure 1 FIG. 1 is a schematic diagram of a plasma generator generating plasma according to an embodiment of the present invention.

[0021] Figure 2 Schematic diagram of air cooling of a reaction chamber upper cover and an air cooling plate according to an embodiment of the present invention.

[0022] Figure 3 Schematic diagram of an air-cooled plate according to one embodiment of the present invention.

[0023] Figure 4 It is a schematic diagram of the assembly and use of a plasma generator and a plasma reaction device according to one embodiment of the present invention. DETAILED DESCRIPTION

[0024] Now, with reference to the accompanying drawings, the specific embodiments of the present invention will be described in detail. What is described here is only the preferred embodiment of the present invention, and those skilled in the art can think of other ways to implement the present invention based on the preferred embodiment, and other ways also fall within the scope of the present invention.

[0025] In this document, the term “plasma generator” refers to a device for generating plasma, which may also be referred to as a “plasma torch.” The term “plasma reaction device” refers to a device in which the plasma generated by the plasma generator reacts with the exhaust gas, including a reaction chamber, such as a reactor.

[0026] The present invention uses, for example, pure oxygen as a plasma carrier gas to replace the nitrogen in the prior art. Pure oxygen can rapidly oxidize the combustible components in the exhaust gas at high temperature, and the energy consumption is reduced by more than half compared with the prior art. It is an ideal new process for exhaust gas treatment. In addition, compared with the high-temperature nitrogen plasma flame of 3000K to 6000K in the prior art, the use of pure oxygen as the carrier gas of the plasma generator reduces the temperature of the plasma flow. For example, its temperature can be 1000K to 3000K, such as 1000K to 2000K. Accordingly, a pure oxygen plasma generator refers to a device that generates oxygen plasma by ionizing oxygen, wherein the generated oxygen plasma is a high-temperature oxygen plasma, and its temperature can be 1000K to 3000K, preferably 1000K to 2000K, and the high-temperature oxygen plasma includes positive ions, negative ions, O + , O 2+ , O - , O 2- , O 3- , ground state particles, excited state particles and other particles.

[0027] A pure oxygen plasma generator (hereinafter referred to as an oxygen plasma generator, or simply referred to as a plasma generator) is described below in conjunction with the accompanying drawings. Figure 1 A cross section of a pure oxygen plasma generator along its central axis and its gas inlet path are shown.

[0028] Specifically, the pure oxygen plasma generator is an axial single arc chamber self-stabilizing arc length plasma generator, including a cathode 1, an electron emitter 2, an anode 3, an anode inner core 4, an anode water chamber 5, and a cathode water chamber 6. The electron emitter 2 is embedded in the bottom of the inner hole at the lower end of the cathode 1 by crimping. The anode 3 is provided with tangential air inlet holes at two locations, and the two are coaxially arranged. The lower end of the cathode 1 is in the shape of a truncated cone, and the upper section is in the shape of a cylinder. The angle of the truncated cone is 10° to 15° smaller than the angle of the concave inverted truncated cone at the entrance of the anode 3, which is convenient for the flow of the carrier gas. In addition, the electron emitter 2 is fixed in the hole at the lower end of the cathode 1 by crimping. After the crimping is completed, the end faces of the cathode 1 and the electron emitter 2 are processed with a turning tool to be flush, flat and smooth. The electron emitter 2 is made of a metal material, such as hafnium, zirconium or silver.

[0029] The inlet of the anode 3 is in the shape of a concave inverted truncated cone, and the angle is generally 100° to 150°. The lower end of the truncated cone of the cathode 1 is connected to the inlet of the anode 3 by shape matching. A cyclone air chamber is formed between the anode 3 and the cathode 1. A primary cyclone air inlet 301 is provided on the side wall of the inverted truncated cone inlet of the anode 3 (correspondingly, the figure shows that the first-stage air intake enters the primary cyclone air inlet 301). The primary cyclone air inlet 301 is not oriented perpendicular to the longitudinal center axis of the plasma generator, but tangentially surrounds the plasma generator and gradually leads to the cyclone air chamber, so that the carrier gas moves in a circular rotation along the air inlet channel of the annular air inlet to form a rotating airflow, that is, a cyclone. As shown in the figure, the anode 3 includes a cylindrical hollow longitudinal airflow channel extending between the inlet and the outlet (i.e., the nozzle of the plasma generator), and the longitudinal airflow channel includes an upper section 31, a middle section 32 and a lower section 33 in sequence from the inlet to the outlet. The diameter of the upper section 31 is smaller than that of the middle section 32 and the lower section 33, the diameter of the middle section 32 is larger than that of the lower section 33, and a chamfer for transition is provided at the connection between the upper section 31, the middle section 32 and the lower section 33. The pure oxygen gas flow enters the upper section 31 through the air inlet and the anode inlet in a swirl manner, and the direction of the channel changes to a longitudinal downward direction. However, the swirl maintains its own rotational momentum (i.e., continues to maintain the swirl), and then flows in a longitudinal downward direction. The gas flow flows through the upper section 31 and enters the middle section 32. At this time, the diameter of the gas flow channel becomes larger, the flow rate becomes slower, and the gas flow is rectified. The anode arc drop point is located at the middle section 32, where there is an O-ring groove to ensure water cooling of the anode and minimize anode ablation; a secondary swirl air inlet 302 is provided below the anode arc drop point (i.e., the lower part of the middle section 32) (correspondingly, the figure shows the secondary air intake entering the secondary swirl air inlet 302), and its structure is the same as the primary swirl air inlet 301, which will not be repeated here. When the primary swirl flows through the middle section 32, the secondary swirl merges, and the two continue to flow together through the lower section 33. Since the diameter of the lower section 33 is reduced, the gas velocity is accelerated.

[0030] The anode core 4 is fixed to the anode water chamber 5 by screws, and the upper part of the anode core 4 is provided with a swirl hole for anode water cooling. The anode core 4 is generally provided with an air inlet swirl hole with a purge function on the current equipment, but after the reaction chamber of the reactor abandons the water cooling chamber, the function of the air inlet swirl hole is set on the air cooling plate 7, and the plasma generator reduces the function of one nitrogen gas, and the structure is greatly simplified. The outer diameter of the plasma generator is only 80mm, and the structure is simple and easy to disassemble; the plasma temperature is high, the operation is stable, and it can be used continuously for more than 3000 hours. In addition to the simple structure and stable use of the plasma generator, pure oxygen is used as the plasma carrier gas. It has been found through experiments that the combustible components in the exhaust gas will burn instantly after encountering the high-temperature pure oxygen plasma, without the intermediate process of heat transfer, so the flame stability is strong and the combustion is complete, which can greatly reduce the explosion and re-combustion accidents of the tail dust.

[0031] It should be noted that the structure of the plasma generator (i.e., oxygen plasma generator) is described herein using pure oxygen as the plasma carrier gas, but this is only an example and is not restrictive; the plasma generator described herein may also use other gases as the plasma carrier gas, such as nitrogen. That is, the structural improvement of the plasma generator is not limited by the type of plasma carrier gas, for example, the design concept of the secondary swirl inlet and the design concept of lengthening the jet outlet of the plasma generator or lengthening the lower section of the longitudinal air flow channel may also be applied to conventional plasma generators using nitrogen as the plasma carrier gas.

[0032] Typically, a plasma generator is assembled with a reactor, so that high-temperature plasma enters the reaction chamber of the reactor from the plasma generator, and exhaust gas also enters the reaction chamber through a corresponding opening in the reaction chamber, and the two meet to cause a combustion reaction. The reaction chamber of the reactor is usually provided with an upper cover, covering the opening of the reaction chamber, and an opening is provided on the upper cover. The plasma generator is installed on the upper cover at its lower end (e.g., outlet or plasma nozzle), so that the lower section of the longitudinal airflow channel of the anode is aligned with the opening of the upper cover, and then the high-temperature plasma passes through the lower section of the longitudinal airflow channel of the anode and enters the reaction chamber through the opening of the upper cover, and burns with the exhaust gas in the reaction chamber. The lower end of the plasma generator and the upper cover can be connected by threads, or connected together by snap fit or other connection methods.

[0033] In the prior art, there are two characteristics regarding the connection between the reaction chamber and the plasma generator and the related combustion reaction. On the one hand, when the plasma generator is installed on the upper cover, the outlet of the plasma generator is adjacent to the opening of the reaction chamber, so that when the high-temperature plasma is ejected at the outlet of the plasma generator, it will first and immediately react with the exhaust gas near the opening of the reaction chamber. On the other hand, since the upper cover covers the opening of the reaction chamber and the combustion of high-temperature plasma and exhaust gas occurs at the opening of the reaction chamber, the temperature at the upper cover and its vicinity is high and needs to be cooled. The prior art usually uses a cooling water chamber to cool the upper cover of the reaction chamber. However, due to the high humidity of the cooling water chamber, the toxic and corrosive exhaust gas in the reaction chamber is easily condensed and liquefied when it contacts the cooling water chamber, so that the condensed droplets are easily accumulated at the outlet of the plasma generator and the opening of the reaction chamber, thereby generating agglomeration of water vapor and dust. With the accumulation of time, the agglomeration is sintered and accumulated into ash slag at the outlet of the plasma generator and the opening of the reaction chamber, that is, an ash slag pile. The presence of the ash pile reduces or blocks the airflow path at the outlet of the plasma generator, affecting the ejection of plasma from the outlet of the plasma generator, making it impossible for the plasma to have comprehensive and good contact with the exhaust gas, reducing the reaction effect of the plasma and the exhaust gas, and causing a decrease in reaction efficiency.

[0034] In addition, since the combustion reaction occurs near the opening of the reaction chamber, the upper cover and the cooling water chamber, the high-temperature plasma can easily burn out the cooling water chamber and other parts in some cases. Moreover, the ash pile sintered at the opening of the reaction chamber requires manual cleaning, which increases the workload and maintenance time.

[0035] In order to avoid the disadvantages of the above-mentioned water cooling solution, the present invention proposes an air cooling solution as an alternative, that is, using gas cooling to cool the upper cover. Specifically, an air cooling plate 7 is provided, such as Figure 2 and Figure 3 As shown, the top of the air cooling plate 7 is open so that the cooling gas can directly contact the upper cover 8 for cooling; however, this is only an example and is not restrictive. The top of the air cooling plate 7 can be closed. The air cooling plate 7 is connected to the lower part of the upper cover 8 of the reaction chamber, and the connection method can be, for example, welding, bolt connection, riveting, gluing, and various other suitable connection methods. Figure 3The air cooling plate 7 includes an air inlet 71, an air outlet 72, and a swirling airflow channel 73 between the air inlet and the air outlet, wherein the air outlet 72 of the air cooling plate 7 is located in the center and aligned with the position of the central opening of the upper cover 8. The figure shows that the air outlet 72 is connected to the airflow channel 73 via a plurality of air outlet holes, and the extension direction of the air outlet holes is not perpendicular to the vertical direction, but tangentially surrounds the vertical direction, so that the cooling gas leaves tangentially through the air outlet holes, forming a circumferential rotating airflow in the air outlet 72. The number and arrangement of the air outlet holes shown in the figure are only examples and are not restrictive; the air outlet holes can be other numbers and spaced evenly or unevenly around the circumferential direction. For example, the air outlet holes can be 2, 3, 5, 6, 7, 8 or more; in one embodiment, the number of the air outlet holes can be 1. The air inlet 71 of the air cooling plate 7 is located at the circumferential outer edge, and an air inlet connector 10 is provided on the upper cover 8 at a position corresponding to the air inlet 71 of the air cooling plate 7, so as to transport the cooling gas to the air inlet 71 of the air cooling plate 7 through the opening of the air inlet connector, and then the cooling gas passes through the air flow channel 73 to reach the air outlet 72. Figure 3 The air cooling plate 7 is shown to be circular in shape, which is only an example, and the air cooling plate 7 may be other suitable shapes, such as triangle, rectangle, pentagon, hexagon and other polygonal shapes, and other suitable regular and irregular shapes.

[0036] Figure 3 The swirling airflow channel 73 is shown in the form of a multi-stage airflow channel of multiple concentric circular rings, each circular ring channel represents a primary airflow channel or represents a part of a multi-stage airflow channel, and the cooling airflow flows through the multi-stage airflow channel to achieve step-by-step cooling. The circular ring channels 73 are separated from each other by multiple concentric circular channel walls 74, and each channel wall is provided with a connecting opening 741, which runs through the height and depth of the entire channel wall, so that a whole gap or notch is formed on the channel wall, and then the channel on the inner side of the channel wall and the channel on the outer side are connected to achieve the circulation of the cooling airflow. The channel wall 74 is circumferential, and multiple channel walls 74 can be concentric with the same shape, and a part of the swirling airflow channel 73 is formed between two adjacent channel walls 74, so that the airflow channel 73 can be in an annular form, such as a circular form.

[0037] In one embodiment, if Figure 3As shown, the connecting openings 741 of two adjacent channel walls 74 are not adjacent to each other, but are opposite to each other, that is, they are opposite to each other at a distance of 180 degrees along the diameter direction of the air-cooling plate 7. The arrangement is made so that the connecting opening 741 of every other channel wall 74 is located on one side of the center of the air-cooling plate 7 along the diameter direction of the air-cooling plate 7, and the connecting openings 741 of the remaining channel walls 74 are located on the other opposite side. For example, along the radial direction from the outside to the inside, the connecting openings of the first channel wall, the third channel wall, the fifth channel wall, and the seventh channel wall are located on one side of the center of the air-cooling plate 7, while the connecting openings of the second channel wall, the fourth channel wall, and the sixth channel wall are located on the other opposite side of the center of the air-cooling plate 7, and the air inlet of the air-cooling plate 7 and the connecting opening of the first channel wall are opposite to each other. As shown Figure 3 As shown by the arrows, the cooling gas is split into two air flow branches from the air inlet 71, which respectively travel along the two halves of the first annular channel formed between the outer wall of the air cooling plate 7 and the first channel wall to the first connecting opening of the first channel wall, that is, one air flow branch travels along the right half of the first annular channel in a clockwise direction to the first connecting opening, and the other air flow branch travels along the left half of the first annular channel in a counterclockwise direction to the first connecting opening.

[0038] Similarly, starting from the first connecting opening, the cooling gas is divided into two airflow branches, which travel along the left and right halves of the second annular channel between the first channel wall and the second channel wall in the clockwise direction and the counterclockwise direction to the second connecting opening of the second channel wall. In the same way, the cooling gas circulates in this way until it reaches the outlet 72 at the center of the air cooling plate 7. The cooling gas is guided to form a swirl in the annular channel, and after flowing through the tangential outlet hole, a swirl is also formed in the outlet 72, so that the cooling gas leaves the outlet hole tangentially. It should be pointed out that the connecting openings of the channel wall are 180 degrees apart in the diameter direction. It is only an example, and it can also have various other configurations. For example, the connecting opening of each channel wall can be set at any position of the channel wall in the circumferential direction, as long as the connecting openings of the two adjacent channel walls are staggered from each other, so that the airflow can form a swirl in the airflow channel. For example, the communicating openings of two adjacent channel walls are staggered at an angle greater than 0 degree and less than or equal to 180 degrees, for example, 30 degrees, 45 degrees, 60 degrees, 90 degrees, 120 degrees, 150 degrees and any other suitable angle.

[0039] In other embodiments, the multi-stage airflow channel of the air cooling plate 7 can be other various suitable shapes and structures. In another embodiment, the multi-stage airflow channel may not be a concentric annular ring, but a concentric polygon, such as a triangle, rectangle or square, pentagon, hexagon or other polygon. Correspondingly, the channel wall is a corresponding concentric polygonal structure, such as a triangle, rectangle or square, pentagon, hexagon or other polygon, and each channel wall is provided with a connecting opening for gas diversion, and the connecting openings of two adjacent channel walls are staggered from each other, so that the airflow can form a swirl in the airflow channel. For example, the angle at which the connecting openings of two adjacent channel walls are staggered from each other is greater than 0 degrees and less than or equal to 180 degrees, for example, staggered 30 degrees, 45 degrees, 60 degrees, 90 degrees, 120 degrees, 150 degrees and any other suitable angle.

[0040] In another embodiment, the multi-stage airflow channel can be spiral, and the channel wall is a continuous spiral channel wall, and there is no connecting opening on the channel wall to divert the gas, so that the cooling airflow starts at the air inlet and goes directly along the spiral channel wall or the spiral airflow channel, thereby forming a rotating vortex in the airflow channel.

[0041] The cooling airflow is delivered to the air inlet 71 of the air cooling plate 7 through the opening of the air inlet connector 10 of the upper cover 8, and then the cooling gas passes through the air flow channel to reach the air outlet 72 of the air cooling plate 7 and the central opening of the upper cover 8, and is mixed with the plasma ejected from the lower end outlet of the plasma generator (i.e., the outlet of the lower section 33 of the plasma nozzle or the longitudinal air flow channel) and is ejected into the reaction chamber. Through this air cooling method and the corresponding air cooling plate arrangement, the possibility of dust agglomeration at the junction of the plasma jet and the reaction chamber is greatly reduced, and the processing efficiency is effectively guaranteed. The cooling gas can be pure oxygen or air. In one embodiment, even for the technical solution of using nitrogen as the plasma carrier gas in the prior art, the problem of ash pile can be avoided by using the air cooling solution proposed in the present invention instead of the water cooling solution; for example, air or nitrogen can be used as the cooling gas to avoid the problem of ash pile in the prior art.

[0042] In addition, in order to avoid the above-mentioned ash pile problem, the present invention further proposes to lengthen the jet outlet of the plasma generator, so that when the plasma generator is installed on the upper cover, the jet outlet of the plasma generator is no longer located near the opening of the reaction chamber, but extends to a deeper position in the reaction chamber, that is, the outlet position of the high-temperature plasma is far away from the opening of the reaction chamber, and the position where the high-temperature plasma reacts with the exhaust gas is moved down to a deep position inside the reaction chamber, avoiding the generation and accumulation of ash piles near the opening of the reaction chamber. Specifically, Figure 2 and Figure 4As shown, the lower end of the outlet of the lower section 33 of the longitudinal airflow channel of the plasma generator 11 (i.e., the plasma nozzle of the plasma generator or the jet outlet of the plasma generator) extends into the reaction chamber, and the distance from the lower surface of the upper cover 8 is greater than or equal to 5 mm. Figure 2 and Figure 4 , it is shown that when the air cooling plate 7 is installed, the distance L between the outlet of the lower section 33 of the longitudinal air flow channel of the plasma generator 11 (i.e., the plasma nozzle of the plasma generator or the jet outlet of the plasma generator) and the lower surface of the air cooling plate 7 is greater than or equal to 5 mm. In the scheme where the air cooling plate 7 is not used, for example, a conventional cooling water chamber is used or the air cooling plate 7 is not installed, the distance between the outlet of the lower section 33 of the longitudinal air flow channel of the plasma generator 11 and the lower surface of the upper cover 8 is greater than or equal to 5 mm.

[0043] With the above arrangement, when the plasma generator is mounted on the upper cover 8 of the reaction chamber, the generated oxygen plasma enters the reaction chamber 12 through the outlet of the plasma generator 11 to a position and depth greater than or equal to 5 mm from the opening of the reaction chamber 12 .

[0044] At the same time, the cooling gas reaches the central opening of the upper cover 8 through the gas outlet of the air cooling plate 7. At this time, since the lower end of the plasma generator 11 extends downward through the central opening of the upper cover 8 to a depth of 5 mm or more, the cooling gas moves downward along the lower end of the plasma generator 11 to reach the lower end outlet of the plasma generator 11 and mixes with the oxygen plasma. For example, when pure oxygen is used as the cooling gas, the pure oxygen is mixed with the oxygen plasma and reacts with the exhaust gas.

[0045] The working process of the plasma reaction device of the present invention and the matching oxygen plasma generator is described below. The oxygen plasma generator 11 is assembled on the plasma reaction device. Specifically, the lower end outlet of the oxygen plasma generator 11 passes through the central opening of the upper cover 8 of the plasma reaction device and extends into the reaction chamber of the plasma reaction device. For example, the distance of the extension is greater than or equal to 5 mm. Since the air cooling plate 7 is arranged below the upper cover 8, the lower end outlet of the oxygen plasma generator 11 also passes through the air outlet of the air cooling plate 7, so that oxygen plasma can enter the reaction chamber of the plasma reaction device through the lower end outlet of the oxygen plasma generator. After assembly, the relevant reaction begins to occur.

[0046] Pure oxygen gas enters through the primary swirl air inlet hole at the top of the anode 3, and is guided in the annular tangential direction of the primary swirl air inlet hole 301, and is transformed from a straight airflow into a swirl airflow, and enters the longitudinal airflow channel along the inverted truncated cone inlet of the anode 3, and is rectified in the middle section 32 of the longitudinal airflow channel with a larger diameter. At this time, another stream of pure oxygen gas is transformed from a straight airflow into a swirl airflow through the secondary swirl air inlet hole 302 at the lower part of the middle section 32. These two streams of air become oxygen plasma in the oxygen plasma generator, and while maintaining their own rotation, they flow downward along the longitudinal airflow channel through the lower section 33, and are accelerated and sprayed into the reaction chamber of the plasma reaction device to a certain depth (for example, greater than or equal to 5 mm) through the outlet of the lower section 33 with a smaller diameter (that is, the lower end outlet of the oxygen plasma generator 11), thereby undergoing an oxidation reaction with the exhaust gas in the reaction chamber.

[0047] At the same time, the upper cover 8 is cooled. Specifically, the cooling gas enters the air cooling plate 7 through the opening of the air inlet joint 10 on the upper cover 8 and reaches the air inlet 71 of the air cooling plate 7. The cooling gas passes through the air flow channel 73 from the air inlet 71 to cool the upper cover 8, and then forms a swirl to reach the air outlet 72, and finally is sprayed into the reaction chamber 12 along the outer surface of the lower end of the oxygen plasma generator 11.

[0048] The present invention provides a plasma reaction device, wherein an upper cover of a reaction chamber is cooled by an air cooling plate, replacing a solution of a cooling water chamber in the prior art. An air flow channel in the air cooling plate adopts a swirling design, such as a concentric ring or a spiral shape, so that the cooling gas forms a swirl in the air flow channel, and the upper cover is cooled step by step or progressively, thereby greatly reducing the possibility of dust agglomeration at the junction of a plasma jet and a reaction chamber, and effectively ensuring the processing efficiency.

[0049] In addition, the present invention provides a plasma generator with a simple structure, easy disassembly and assembly, and a small size. It is used in conjunction with a plasma reaction device, and can use, for example, pure oxygen as a plasma carrier gas. The generated plasma is 1000K to 3000K, for example, 1000K to 2000K, which is greatly reduced compared to the high-temperature nitrogen plasma of 3000K to 6000K in the prior art, so that the reaction temperature is reduced, and the safety and operating life are improved; in addition, the combustion flame with the exhaust gas has strong stability and good combustion completeness, which can greatly reduce the explosion and re-combustion accidents of the tail dust. In addition, by additionally arranging a tangential secondary swirl air inlet below the anode arc point of the plasma generator, the power supply is kept stable and the service life of the plasma generator is improved. In addition, the lower end outlet of the plasma generator is lengthened, so that the outlet position of the high-temperature plasma is far away from the opening of the reaction chamber, and the position where the high-temperature plasma reacts with the exhaust gas is moved down to a deep position inside the reaction chamber, avoiding the generation and accumulation of ash piles near the opening of the reaction chamber.

[0050] The above description of various embodiments of the present invention is provided to one of ordinary skill in the relevant art for the purpose of description. It is not intended that the present invention be exclusive or limited to a single disclosed embodiment. As above, a person of ordinary skill in the field of the above teachings will understand the various substitutions and variations of the present invention. Therefore, although some alternative embodiments are specifically described, a person of ordinary skill in the art will understand or relatively easily develop other embodiments. The present invention is intended to include all substitutions, modifications and variations of the present invention described herein, as well as other embodiments that fall within the spirit and scope of the present invention described above.

[0051] Reference numerals:

[0052] 1 cathode

[0053] 2Electron emitter

[0054] 3 Anode

[0055] 301 primary swirl air inlet

[0056] 302 secondary swirl air inlet

[0057] 31 Upper section of the longitudinal airflow channel

[0058] 32 Middle section of the longitudinal airflow channel

[0059] 33 Lower section of the longitudinal airflow channel

[0060] 4Anode core

[0061] 5Anode water chamber

[0062] 6Cathode water chamber

[0063] 7 air-cooled plates

[0064] 71 Air Inlet

[0065] 72 outlet

[0066] 73 Rotary airflow channel

[0067] 74 channel wall

[0068] 741 Unicom opening

[0069] 8 Upper cover

[0070] 9 Plasma

[0071] 10 Air intake connector

[0072] 11 Plasma Generator

[0073] 12 reaction chambers

Claims

1. A plasma reaction device, comprising: Reaction chamber (12); An upper cover (8), the upper cover (8) covers the reaction chamber (12) and comprises a central opening and an air inlet connector (10) separated from the central opening; The plasma reaction device is characterized in that the plasma reaction device further comprises an air cooling plate (7) arranged below the upper cover (8), the air cooling plate (7) comprising an air inlet (71), an air outlet (72) and a swirling airflow channel (73) located between the air inlet (71) and the air outlet (72), the air inlet (71) being aligned with the air inlet connector (10), and the air outlet (72) being aligned with the central opening, so that cooling gas enters the air inlet (71) via the air inlet connector (10), forms a swirling airflow in the swirling airflow channel (73) and is discharged via the air outlet (72), thereby cooling the upper cover (8).

2. The plasma reaction device according to claim 1, characterized in that: The air cooling plate (7) comprises a plurality of concentric circumferential channel walls (74) of the same shape, and a portion of the swirling airflow channel (73) is formed between two adjacent circumferential channel walls (74).

3. The plasma reaction device according to claim 2, characterized in that: A connecting opening (741) is provided on each circumferential channel wall (74) to connect the swirling airflow channels (73) on the inner and outer sides of the connecting opening (741); the connecting openings (741) of two adjacent circumferential channel walls (74) are staggered from each other in the circumferential direction, so that the cooling airflow is split at each connecting opening (741) and flows to the next connecting opening in the direction of the air outlet (72).

4. The plasma reaction device according to claim 3, characterized in that: The communicating openings (741) of two adjacent circumferential channel walls (74) are staggered by 30 to 150 degrees in the circumferential direction.

5. The plasma reaction device according to claim 3, characterized in that: The communicating openings (741) of two adjacent circumferential channel walls (74) are circumferentially staggered and opposed to each other by 180 degrees.

6. The plasma reaction device according to claim 4 or 5, characterized in that: The circumferential channel wall (74) is a polygonal channel wall.

7. The plasma reaction device according to claim 4 or 5, characterized in that: The circumferential channel wall (74) is a circular channel wall.

8. The plasma reaction device according to claim 1, characterized in that: The swirling airflow channel (73) is a continuous spiral channel.

9. A plasma generator, configured to be used in conjunction with a plasma reaction device according to any one of claims 1 to 8, comprising a cathode (1) and an anode (3) installed below the cathode (1), wherein the interior of the anode is hollow and provided with a longitudinal airflow channel, wherein the longitudinal airflow channel includes an upper section (31), a middle section (32) and a lower section (33) in sequence from the inlet to the outlet of the anode (3), and a primary swirl air inlet (301) tangentially surrounding the plasma generator is provided on the side wall of the inlet of the anode, and a carrier gas forms a swirling airflow through the primary swirl air inlet (301) and enters the longitudinal airflow channel, characterized in that: The lower section (33) protrudes longitudinally from the bottom transverse flange of the plasma generator, so that when the bottom transverse flange of the plasma generator is installed on the upper cover (8), the outlet of the lower section (33) extends into the interior of the reaction chamber (12) and the distance from the lower surface of the upper cover (8) is greater than or equal to 5 mm.

10. The plasma generator according to claim 9, characterized in that: A secondary cyclone inlet hole (302) tangentially surrounding the plasma generator is provided on the side wall below the arc landing point of the anode (3), so that the carrier gas entering from the primary cyclone inlet hole (301) is mixed with the carrier gas entering from the secondary cyclone inlet hole (302).

11. The plasma generator according to claim 9, characterized in that: The inlet of the anode (3) is configured to allow oxygen to flow into the anode.

12. The plasma generator according to claim 9, characterized in that: The distance L between the outlet of the lower section (33) and the lower surface of the air cooling plate (7) is greater than or equal to 5 mm.

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