CN105180183A - Plasma combustion-supporting Swiss roll combustor - Google Patents

Abstract

The invention provides a plasma combustion-supporting swiss roll burner, which belongs to the technical field of low calorific value gas utilization. Including combustion chamber and spiral plate channel, specifically including burner shell, deflector, porous medium, inlet channel, outlet channel, discharge device, ozone inlet, temperature measuring hole, ignition hole, observation hole, metal high voltage electrode plate, The electrode lead wire and the exhaust chimney. The burner is round or square, and the upper and lower ends are sealed by sealing plates. There are heat-resistant materials, and the combustion chamber is wrapped with heat-insulating materials. The discharge device and deflector are located at the entrance of the combustion chamber, and the ozone inlet is set at the outermost ring of the spiral plate channel. The burner is combined with a plasma discharge device or an ozone generator and a porous medium material to achieve the purposes of reducing energy consumption, eliminating poison and the like.

Description

A plasma-assisted combustion swiss roll burner

technical field

The invention relates to the technical field of low calorific value gas (exhaust gas) utilization, in particular to a plasma combustion-supporting swiss roll burner.

Background technique

my country is a country with a large energy demand, but the efficiency of energy utilization cannot reach a high level due to the defects of technical means. When people exploit and use various energy resources, some "waste gas" containing a small amount of combustible components and low calorific value is directly discharged into the atmosphere without being utilized, such as gas emitted during coal mining and torches in petrochemical industries. Evacuated hydrocarbon waste gas, associated natural gas discharged from oil and gas field exploitation, landfill gas generated from landfill, flammable and toxic waste gas generated during chemical industry production, etc. The direct discharge of these "exhaust gases" containing combustible components or toxic gases pollutes the environment and wastes energy.

Generally, gases with a calorific value less than 6.28MJ/ ^m3 are called low calorific value gases, but the calorific value of the "exhaust gas" mentioned in the previous section is much lower than this value. Due to the restriction of the flammability limit, traditional combustion methods cannot be used. deal directly with. Taking methane gas as an example, its flammability limit is about 5%-15% under normal conditions, and the calorific value of the above-mentioned low calorific value combustible waste gas is converted into methane, and the corresponding volume concentration of methane is generally between 0.5-3%, which is much lower than In the flammable limit range, the conventional combustion organization method cannot be used for direct treatment, and enterprises often choose to discharge directly, causing environmental pollution.

At present, the technologies for treating these low calorific value combustible waste gases in industry mainly include: combustion technology, biological purification technology, membrane separation technology, adsorption technology and condensation technology, among which combustion is currently the most important and most effective treatment method. There are three main types of combustion: direct combustion, thermal combustion, and catalytic combustion. When the combustible components are low, direct combustion is not enough to maintain; when the combustible components are very low, thermal combustion or regenerative combustion can no longer keep the temperature at the temperature required for combustion; when the combustible components are slightly higher, the combustion temperature is also If it is high, it will lead to problems such as catalyst failure. Therefore, a better treatment method is to recycle the heat of the flue gas and add additional energy to the system to help deal with extremely low calorific value combustible exhaust gas, and the Swiss roll burner can achieve this purpose.

The existing Swiss roll burners are mostly researched on the micro-scale of MEMS, and due to the large specific surface area of its structure, the problem of heat dissipation is relatively serious and the fuel concentration is near the equivalence ratio. Bulk discharge technology combined with Swiss roll burners of medium and large sizes is the application phase.

Contents of the invention

The technical problem to be solved by the present invention is to provide a plasma combustion-supporting swiss roll burner, which is suitable for industrial "waste gas" with a small amount of combustible components and low calorific value, such as low calorific value blast furnace gas and coke oven gas discharged from the iron and steel industry. Combustion of methane gas discharged during coal mining, hydrocarbon waste gas evacuated by flare in petrochemical industry, associated natural gas discharged in oil and gas field exploitation, landfill gas generated by landfill, flammable and toxic waste gas generated during chemical industry production, etc. .

The burner includes a burner shell, a combustion chamber, a spiral plate channel, an upper cover plate and a lower bottom plate, specifically including a deflector plate, a porous medium, an air inlet channel, an air outlet channel, a discharge device, an ozone inlet, a temperature measuring hole, and an ignition chamber. hole, observation hole, metal high-voltage electrode plate, electrode lead wire and exhaust chimney, the burner is sealed by the upper cover plate and the lower bottom plate, and the observation hole is set on the upper cover plate to observe the ignition and combustion state and monitor whether the flame is extinguished. The two ends of the spiral plate channel are the inlet channel and the air outlet channel respectively. The combustion chamber is located in the center of the spiral plate channel. The deflector and the discharge device are located at the entrance of the combustion chamber. The porous medium is located in the center of the combustion chamber. At the inlet, two temperature measuring holes are set at the opposite position of the outermost ring of the spiral plate channel, and two temperature measuring holes are set at the opposite position of the innermost ring of the spiral plate channel. The discharge device is composed of a metal high-voltage electrode plate set on an insulating material. The high-voltage electrode plate leads out the lead wires of the electrodes, and the exhaust chimney is connected to the outside of the gas outlet channel.

Among them, the burner is square or circular, the upper cover plate, the lower bottom plate of the burner and each spiral plate are sealed with each other, and the surfaces of the high temperature sides in the combustion chamber are covered with heat-resistant materials. The air inlet passage and the air outlet passage are of variable cross-section structure, the variable cross-section structure of the air inlet passage ensures that the gas entering the burner is evenly distributed in the pipe, and the secondary electrode plate is inlaid on the wall of the air inlet variable cross-section passage, so that the gas to be treated Exhaust gases are ionized before entering the burner. The upper cover plate and the lower base plate are welded on the upper and lower ends of the burner. Among them, a hole is opened in the center of the lower base plate, which is the ignition hole. The ignition hole is covered with a ceramic sleeve, which is used for ignition and ensures that the ignition hole will not be damaged by high temperature. When the burner is running stably, it can also be used as an ozone inlet. The deflector is installed on the side wall of the combustion chamber along the direction of the airflow path. Porous media is used to maintain the stability of combustion. It is composed of one or more of foamed ceramics, honeycomb ceramics or flat ceramics with uniform porosity and pore diameter, or layered changes. The pore diameter varies from 0.5 to 8mm. The range of variation is 0.15-0.85.

The burner casing is a Swiss-rolled parallel gas and exhaust gas channel, that is, a heat exchange structure shaped like a spiral plate, and always keeps the inlet channel wrapped outside the outlet channel to ensure sufficient heat exchange between fluids and reduce environmental impact. Heat dissipation.

The discharge device is composed of a high-voltage power supply, electrodes, and insulating materials. The plasma generation method is one of glow discharge, corona discharge, dielectric barrier discharge, radio frequency discharge, microwave discharge, sliding arc discharge, and jet discharge; the high-voltage power supply is High-voltage high-frequency AC power supply, high-voltage high-frequency pulse power supply, high-voltage radio frequency power supply or microwave power supply, among which, the frequency of high-voltage high-frequency AC power supply is 50Hz-20kHz, the peak voltage is 10Kv-60Kv; the pulse frequency of high-voltage high-frequency pulse power supply is 50Hz-20kHz , the peak voltage is 10kV-100Kv, the pulse width is 100ns-10us; the frequency of high-voltage radio frequency power supply is 1-100mHz, the peak voltage is 5000V-10000V; the electrode material is one of stainless steel, molybdenum and graphite; the insulating material is ceramic, oxide One of aluminum, resin, polytetrafluoroethylene. The ozone generator can be fed directly with oxygen, air or oxygen-containing waste gas to generate ozone-containing gas and then pass it into the burner. The ozone generator can be air-cooled or water-cooled. The ozone output of the air source ozone generator is 5g/L-50g/L, and the concentration is about 5mg/L-15mg/L; the ozone output of the oxygen source ozone generator is 10g/L-100g/L, and the concentration is about 50mg/L- 100mg/L.

A first-level electrode interface is provided on the lower base plate corresponding to the entrance of the combustion chamber, and ozone gas inlets are also provided on the lower base plate corresponding to several positions along the air intake passage. The first-level plasma discharge device is placed at the entrance of the combustion chamber, and its non-grounded metal electrodes (plates, wires or nets) are insulated and fixed by heat-resistant dielectric materials and connected from the lower bottom plate; the second-level plasma discharge device is placed at the entrance The inner wall of the air inlet is parallel to the airflow direction and vertically inlaid with high-temperature resistant metal electrodes (plates, wires or nets). on the inner wall of the entrance. The ground terminal can be connected directly to the burner housing. The wires connecting the electrodes are covered with insulating material and lead out from the lower bottom plate to the burner shell to connect to the power supply.

According to the calorific value of gas (exhaust gas), under the condition of high calorific value and stable combustion, heat utilization units such as evaporators can be installed in the combustion chamber to utilize the heat generated by combustion.

The beneficial effects of above-mentioned technical scheme of the present invention are as follows:

The invention strengthens the heat exchange between the flue gas and the reactants through the unique shape of the Swiss roll, utilizes the characteristics of high thermal conductivity and strong radiation ability of the porous medium structure, and adds a plasma discharge device into the burner to produce oxidized Combustible particles or particles that promote combustion and are more reactive can burn combustible gases with low calorific value and low concentration and reduce pollution emissions.

The present invention combines the advantages of plasma combustion-supporting technology, porous medium heat storage technology, and flue gas heat recirculation technology, with lower energy consumption and a wide range of concentrations of combustible waste gas with low calorific value; and the position and power of the plasma generating device can be adjusted. Adjustment, so the operation of the equipment is easy to control. Due to the low calorific value of the fuel it targets, the combustion temperature is much lower than that of ordinary combustion, so the harmful gases directly related to temperature such as NO _x are greatly reduced, effectively solving the problem of smooth ignition and maintenance of combustion of low calorific value exhaust gas The problem is an example of successful utilization of this part of the waste gas, which not only recovers energy but also reduces environmental pollution.

Description of drawings

Fig. 1 is the structural representation of the plasma combustion-supporting swiss roll burner (circle) of the present invention;

Fig. 2 is the structural representation of the plasma combustion-supporting Swiss roll burner (square) of the present invention;

Fig. 3 is the layout drawing of the (circular) upper cover plate of the plasma combustion-supporting Swiss roll burner of the present invention;

Fig. 4 is the layout drawing of the upper cover plate of the plasma combustion-supporting Swiss roll burner (square) of the present invention;

Fig. 5 is the layout drawing of the bottom plate of the plasma combustion-supporting Swiss roll burner (circular) of the present invention;

Fig. 6 is the layout diagram of the bottom plate of the plasma combustion-supporting Swiss roll burner (square) of the present invention;

Fig. 7 is the front view of the variable-section air intake channel of the plasma-assisted combustion Swiss roll burner of the present invention;

Fig. 8 is the left side view of the variable-section air intake channel of the plasma-assisted combustion Swiss roll burner of the present invention;

Fig. 9 is the front view of the variable-section air outlet channel of the plasma-assisted combustion Swiss roll burner of the present invention;

Fig. 10 is the left side view of the variable-section gas outlet channel of the plasma combustion-supporting Swiss roll burner of the present invention;

Fig. 11 is a schematic structural view of a plasma combustion-supporting Swiss roll burner (circular) discharge device of the present invention;

Fig. 12 is a schematic structural diagram of a plasma-assisted combustion swiss roll burner (square) discharge device of the present invention.

Among them, 1-burner shell; 2-deflector; 3-porous medium; 4-outlet channel; 5-intake channel; 6-discharge device; 7-heat-resistant material; 8-ozone inlet; Temperature hole; 10-ignition hole; 11-observation hole; 12-metal high-voltage electrode plate; 13-electrode lead wire; 14-insulating material; 15-exhaust chimney.

detailed description

In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will describe in detail with reference to the drawings and specific embodiments.

The invention provides a plasma-assisted combustion swiss roll burner.

As shown in Figures 1 and 2, the burner is square or circular, including a burner casing 1, a combustion chamber, a spiral plate channel, an upper cover and a lower bottom, and the burner is sealed by the upper cover and the lower bottom, as As shown in Figure 3 and Figure 4, the observation hole 11 is arranged on the upper cover plate, the two ends of the spiral plate channel are the air intake channel 5 and the air outlet channel 4 respectively, the combustion chamber is located in the center of the spiral plate channel, the deflector 2 and the discharge device 6 Located at the entrance of the combustion chamber, the porous medium 3 is located in the center of the combustion chamber, an ozone inlet 8 is set at the outermost ring of the spiral plate channel, two temperature measuring holes 10 are set at the opposite position of the outermost ring of the spiral plate channel, and at the innermost part of the spiral plate channel Two temperature measuring holes 10 are set at the relative position of the ring, as shown in Figure 11 and Figure 12, the discharge device 6 is composed of a metal high-voltage electrode plate 12 arranged on an insulating material 14, and the metal high-voltage electrode plate 12 leads to an electrode lead-out wire 13, as shown in the figure 9 and FIG. 10 , the exhaust chimney 15 is connected to the outside of the air outlet channel 4 . The upper cover plate, the lower bottom plate of the burner and each spiral plate are sealed with each other, and the surfaces of the high-temperature sides in the combustion chamber are covered with heat-resistant materials 7 . As shown in FIG. 7 and FIG. 8 , the air inlet channel 5 and the air outlet channel 4 are variable cross-sectional structures. As shown in FIG. 5 and FIG. 6 , a hole is opened in the center of the lower bottom plate, which is an ignition hole 10 , and a ceramic sleeve is set inside the ignition hole 10 .

The deflector 2 is installed along the airflow path direction on the side wall of the combustion chamber. The porous medium 3 is composed of one or more of foam ceramics, honeycomb ceramics or flat ceramics with uniform porosity and pore diameter or gradually changing or layered changes. .

The burner is a device for burning and utilizing waste gas with low calorific value. Its periphery is made of Swiss coiled spiral plate, and its material can be a material with a temperature resistance above 800°C. In order to ensure that the material stays in a high-temperature state for a long time without failure, it is necessary to coat the cement-like heat-resistant material 7 on the walls of high-temperature areas such as the combustion chamber. When the high-temperature flue gas enters the heat exchange channel, the temperature will gradually decrease, while the enthalpy value of the cold intake air increases with the increase of the preheated temperature. When the enthalpy value of the exhaust gas that is difficult to burn and treat increases to a certain value, Gas will be able to sustain combustion.

There are however two issues that need to be addressed here, the first is where the flame stays. We know that the position of the premixed laminar combustion flame is directly related to the gas flow rate and type, that is, when the speed is small, the flame drifts upstream, and when the flow rate is high, the flame drifts downstream. For the Swiss roll burner, it is necessary to stabilize the flame position in the middle of the combustion chamber, so it is necessary to fill the central combustion chamber with a porous medium 3 material layer to organize regenerative combustion, and because the combustion chamber has a large volume, it is conducive to fully mixed combustion of gas , It also makes it difficult for the flame to migrate into the channel and burn the gas channel. When the gas concentration is low and the combustion conditions are relatively harsh, the plasma discharge device is placed in the gas channel or combustion chamber, and the dissociated particles produced can promote combustion and also help the flame to stabilize in the combustion chamber.

The second is the ability of the burner to deal with low-concentration exhaust gas. First of all, consider that the amount of waste gas to be treated should not be too small, that is, it is different from the size of the micro burner; secondly, because the low-concentration gas is difficult to ignite, it is possible to burn it only when it is preheated to a very high temperature, so the Swiss roll is used The heat exchange channels of the structure can do this. Considering that the burner needs to preheat the initial gas to a higher temperature, the designed heat exchange channel is longer to ensure that the initial gas can be preheated from room temperature to the temperature required for exhaust gas combustion. In addition, the improvement of the burning speed of lean-burn fuel by ozone is significantly more than that under the condition of equivalence ratio and rich-burning conditions, and the particles generated by the plasma discharge device also contain ozone, in addition to O, O3, OH, CH3, Particles such as H all promote the combustion of ultra-low calorific value gases, thereby reducing the gas-lean flammability limit. The burner is equipped with a primary plasma discharge device 6 at the entrance of the central combustion chamber to directly ionize the gas in the combustion chamber; a secondary plasma discharge device is provided at the entrance of the air intake passage to ionize the initial gas in advance; A number of ozone gas inlets 8 are provided along the process, and ozone is directly added to the burner to support combustion. Since the ionized particles are usually very active, they will decompose rapidly at a slightly higher temperature. Therefore, a secondary plasma discharge device placement port is set up along the way, and the specific installation location of the plasma discharge device is selected according to different temperature conditions. The ionized particles are mixed with the premixed gas before disappearing. When the temperature is preheated to the corresponding temperature, the chain reaction of the fuel will occur relatively easily, which will promote the oxidative combustion of the fuel. In addition, the ozone generator can also produce highly oxidizing substances, which can also achieve the purpose of extending the flammability limit. However, because ozone is sensitive to temperature conditions, it will decompose into oxygen at a later temperature, so it needs to be added at a suitable position. to play a role.

The high-voltage electrode material of the present invention is made of metals such as copper or stainless steel, and the structure can be a flat electrode, a cylindrical electrode, a prickly electrode or a polygonal electrode. The way to generate plasma can be one of glow discharge, corona discharge, dielectric barrier discharge, radio frequency discharge, sliding arc discharge, and jet discharge. The high-voltage power supply can be a high-voltage and high-frequency AC power supply, a high-voltage pulse power supply, or a radio frequency power supply. The frequency of high-voltage high-frequency AC power supply is 50Hz-20kHz, and the peak voltage is 10Kv-60Kv; the pulse frequency of high-voltage high-frequency pulse power supply is 50Hz-20kHz, the peak voltage is 10kV-100Kv, and the pulse width is 100ns-10us; the frequency of high-voltage radio frequency power supply is 1 -100mHz, peak voltage is 5000V-10000V. Active groups such as OH generated by the plasma generator used in the present invention have super-reactivity and can react with waste gas that is difficult to react under conventional conditions. The electron temperature in low-temperature plasma is as high as tens of electron volts, while the gas temperature is only a few hundred degrees, which has great advantages in industrial applications.

The structure of the porous medium 3 filled in the combustion chamber of the present invention can be composed of one or more of foam ceramics, honeycomb ceramics or flat ceramics with uniform porosity and pore diameter or gradually changing or layered changes, and the pore diameter variation range is 0.5- 8mm, the range of porosity is 0.15-0.85. The advantages of porous media materials are high thermal conductivity, high specific surface area, and high porosity, which can not only fully disturb the flow, accelerate gas mixing for temperature exchange, but also effectively transfer the heat of the flue gas after the reaction to the intake air efficiently and fully. Thereby effectively reducing the loss of energy.

In addition to the burner body, porous dielectric material, plasma discharge device and ozone generator, the present invention also needs to be equipped with methane, oxygen and nitrogen cylinders, flow meters, gas distribution systems, ceramic tubes and quartz glass. The design dimensions of the burner include the height of the burner, the width of the channel, the wall thickness of the channel, the side length of the central combustion chamber, the length of the channel, the diameter of the inlet and outlet holes, and the length of the gas channel with a gradual cross section. The structure is simple in design and processing, and can be produced industrially.

The specific working process of the burner is as follows:

(1) The methane air of the equivalence ratio is passed into the combustion chamber from the air intake channel 5 and the central ignition hole 10 of the lower base plate and ignited, so that the material of the porous medium 3 is heated to above 1300-1700K.

(2) Gradually reduce and finally close the methane fed into the lower floor, and at the same time reduce the concentration of methane in the inlet of the gradually widening port to the combustible waste gas with low calorific value to be treated. During this process, the matching relationship between gas flow and concentration is adjusted to stabilize the combustion. center of the combustion chamber.

(3) Install and place a number of plasma discharge devices 6 as required in the air intake passage along the course. The electrode lead wire 13 wrapped by quartz material leads to the lower bottom plate and plays the role of fixing the metal high-voltage electrode plate 12. At the same time, the discharge device 6 is welded and fixed. metal bosses. When in use, connect the wire to the high-voltage power supply, and ground the outer wall of the burner, so that a discharge area is set in the channel, and when the gas is fed, the gas will be ionized. The addition of plasma can further reduce the lean flammability limit of the gas, so reduce the concentration of combustible components in the inlet gas, and observe whether there is flame maintenance in the combustion chamber; if there is still flame maintenance, the concentration of combustible components can be further reduced; if the temperature continues to drop to flameout, then It is necessary to adjust the parameters such as the position of the plasma discharge device 6 and the discharge voltage to reduce the lean fuel flammability limit as much as possible. Or adding ozone at different positions along the air intake can also achieve a similar purpose.

(4) Collect the high-temperature clean flue gas after combustion treatment and detect its components to investigate the completeness of the reaction. Then it is discharged into the environment through the air outlet channel 4, at this time, the combustible and harmful components contained in the flue gas will be greatly reduced.

The burner uses the heat storage effect of the porous medium 3 material, the heat exchange effect of the spiral channel, and the oxidation effect of plasma radical particles to co-process the low calorific value combustible waste gas, so that the gas that is difficult to be used is successfully oxidized and burned to release its energy. At the same time, it also converts combustible waste gas that is harmful to the environment into carbon dioxide, water and other environmentally harmless substances, which has the advantages of small heat energy dissipation and low pollution emissions.

The above description is a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, these improvements and modifications It should also be regarded as the protection scope of the present invention.

Claims (7)

1. A plasma combustion-supporting swiss roll burner, comprising a burner casing (1), a combustion chamber, a spiral plate passage, an upper cover plate and a lower base plate, is characterized in that: specifically comprise a deflector (2), a porous medium ( 3), air inlet channel (5), air outlet channel (4), discharge device (6), ozone inlet (8), temperature measuring hole (9), ignition hole (10), observation hole (11), metal high pressure The electrode plate (12), the electrode lead wire (13) and the exhaust chimney (15), the burner is sealed by the upper cover plate and the lower bottom plate, the observation hole (11) is set on the upper cover plate, and the two ends of the spiral plate channel are respectively Intake channel (5) and outlet channel (4), the combustion chamber is located at the center of the spiral plate channel, the deflector (2) and the discharge device (6) are located at the entrance of the combustion chamber, and the porous medium (3) is located at the center of the combustion chamber. The outermost ring of the spiral plate channel is provided with an ozone inlet (8), two temperature measuring holes (10) are arranged at the relative position of the outermost ring of the spiral plate channel, and two temperature measuring holes (10) are arranged at the relative position of the innermost ring of the spiral plate channel. ), the discharge device (6) is composed of a metal high-voltage electrode plate (12) arranged on an insulating material (14), the metal high-voltage electrode plate (12) leads to the electrode lead wire (13), and the exhaust chimney (15) is connected to the outlet channel (4) EXTERNAL. 2. A plasma combustion-supporting swiss roll burner according to claim 1, characterized in that: the burner is square or circular, and the upper cover plate, the lower bottom plate of the burner and each spiral plate are mutually sealed , each high-temperature side surface in the combustion chamber is covered with a heat-resistant material (7). 3. A plasma combustion-supporting swiss roll burner according to claim 1, characterized in that: the inlet channel (5) and the outlet channel (4) are variable-section structures. 4. A plasma combustion-supporting Swiss roll burner according to claim 1, characterized in that: the upper cover plate and the lower base plate are welded to the upper and lower ends of the burner, wherein a hole is opened in the center of the lower base plate as an ignition hole (10), the ignition hole (10) is covered with a ceramic bushing. 5. A plasma-assisted combustion swiss roll burner according to claim 1, characterized in that: the deflector (2) is installed on the side wall of the combustion chamber along the direction of the airflow path. 6. A kind of plasma combustion-supporting swiss roll burner according to claim 1, characterized in that: the porous medium (3) is made of ceramic foam, honeycomb ceramic or One or several components in flat ceramics, the pore diameter ranges from 0.5-8mm, and the porosity ranges from 0.15-0.85. 7. A kind of plasma combustion-supporting swiss roll burner according to claim 1, characterized in that: the discharge device (6) is composed of a high-voltage power supply, electrodes, and insulating materials (14), and the method of generating plasma is bright One of photodischarge, corona discharge, dielectric barrier discharge, radio frequency discharge, microwave discharge, sliding arc discharge, jet discharge; the high voltage power supply is high voltage high frequency AC power supply, high voltage high frequency pulse power supply, high voltage radio frequency power supply or microwave power supply, Among them, the frequency of high-voltage high-frequency AC power supply is 50Hz-20kHz, and the peak voltage is 10Kv-60Kv; the pulse frequency of high-voltage high-frequency pulse power supply is 50Hz-20kHz, the peak voltage is 10kV-100Kv, and the pulse width is 100ns-10us; the frequency of high-voltage radio frequency power supply The peak voltage is 1-100mHz, and the peak voltage is 5000V-10000V; the electrode material is one of stainless steel, molybdenum and graphite; the insulating material (14) is one of ceramics, aluminum oxide, resin and polytetrafluoroethylene.