Dielectric barrier discharge plasma experimental device
By introducing circulating water heating and electric heating units into the dielectric barrier discharge plasma experimental device, combined with electrode spacing and shape adjustment, precise control of temperature and discharge parameters is achieved, solving the problem of precise temperature control and difficulty in picking and discharging of materials, and improving the problem of Experimental accuracy and operational convenience.
Patent Information
- Application Number
- CN202420957921.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-07
- Publication Date
- 2024-12-20
- Estimated Expiration
- 2034-05-07
AI Technical Summary
The existing dielectric barrier discharge plasma experimental devices are difficult to achieve precise temperature control and convenience of picking and discharging materials, which affects experimental accuracy and operating efficiency.
A device including a plasma reaction chamber, an electrode unit, a plasma generation unit, a circulating water heating unit and an electric heating unit is designed. The temperature is monitored by a thermocouple and the temperature control is realized using circulating water and electric heating, and the electrode spacing and shape are adjusted. To control discharge parameters, simplify the catalyst placement and removal process.
The temperature adjustable and controllable of plasma reaction is achieved, which improves experimental accuracy and repeatability, simplifies the operation process of the catalyst, and reduces experimental errors.
Smart Images
Figure CN222216015U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of dielectric barrier discharge plasma experiments, in particular to a dielectric barrier discharge plasma experiment device. Background Art
[0002] Plasma state is one of the material states of matter. Matter that enters the plasma state is called plasma. They are usually composed of high-energy electrons, ions, free radicals, etc., and have good conductivity. Because the total charge of positive ions produced by ionization is the same as the total charge of electrons and negative ions, plasma is an electrically neutral gas-like substance from a macroscopic point of view. About 99% of matter in the universe is plasma. For example, the sun is a sphere composed of a large amount of hot plasma. There are few plasmas that can exist stably on the earth. Common plasmas in nature include lightning, flames, and the earth's ionosphere. Plasma can be produced in a wide range of pressure, temperature, electron temperature and electron density, so there are many classification standards for plasma, and it is difficult to classify plasma using a general method. The most common classification method is to divide plasma into two categories according to temperature: high-temperature plasma and low-temperature plasma. Low-temperature plasma discharges under different driving frequencies, electrode structures, and generation media can produce pulsed corona discharge plasma, pulsed glow discharge plasma, glow discharge plasma, micro hollow cathode discharge plasma, dielectric barrier discharge plasma, radio frequency discharge plasma, and microwave discharge plasma.
[0003] In recent years, the importance of clean energy has been increasing both at home and abroad, and people hope to replace traditional thermal catalytic hydrogen production with a new technology with lower energy consumption. Since dielectric barrier discharge plasma has the advantages of fast reaction speed, low reaction temperature, and can be turned on and off at any time, the use of dielectric barrier discharge plasma to produce hydrogen is a very potential alternative to thermal catalytic technology. It is favored by scholars in the industry and has gradually become a hot topic in the research of new energy related fields. At present, the raw materials used for low-temperature plasma hydrogen production research mainly include methane, gasoline, heavy hydrocarbons, diesel, alcohols, ethers, etc. In addition, dielectric barrier discharge plasma technology is also widely used in catalyst preparation and carbon dioxide conversion.
[0004] The classic dielectric barrier discharge plasma reactor adopts a parallel plate structure or a coaxial cylindrical structure, with at least one dielectric layer placed between the electrodes. Some reaction devices have dielectric covering on the surface of both the low-voltage electrode and the high-voltage electrode. Since the electrodes are not directly exposed to the ionized gas, the high-energy particles generated during the reaction will not directly bombard the electrodes to cause damage, and the generated deposits will not adhere to the electrode surface and affect the discharge.
[0005] At present, it is difficult to achieve in-situ reactions with precise temperature control in common dielectric barrier discharge plasma experimental devices, which leads to the inability to unify experimental conditions and affects the experimental accuracy. In addition, there is also the problem of difficulty in taking and placing materials, which affects the experimental operation. Utility Model Content
[0006] In view of this, the purpose of the utility model is to provide a dielectric barrier discharge plasma experimental device so as to achieve precise temperature control, improve experimental accuracy, and at the same time, improve the convenience of taking and placing materials.
[0007] The utility model solves the above problems through the following technical means:
[0008] The utility model provides a dielectric barrier discharge plasma experimental device, comprising a plasma reaction chamber, an electrode unit for applying voltage to the plasma reaction chamber, and a plasma generating unit electrically connected to the electrode unit; the plasma reaction chamber is provided with a feed pipe and a discharge pipe, a thermocouple is arranged in the plasma reaction chamber, and also comprises a temperature display instrument, a circulating water heating unit for realizing the reaction of the plasma reaction chamber in a low temperature range, and an electric heating unit for realizing the reaction of the plasma reaction chamber in a high temperature range, and the temperature display instrument is electrically connected to the thermocouple.
[0009] Furthermore, the electrode unit includes an electrode mounting seat, an upper electrode plate, an upper electrode terminal, a lower electrode plate and a lower electrode terminal. The upper electrode plate, the upper electrode terminal, the lower electrode plate and the lower electrode terminal are all installed on the electrode mounting seat, the upper electrode plate is electrically connected to the upper electrode terminal, the lower electrode plate is electrically connected to the lower electrode terminal, and the plasma reaction chamber is arranged between the upper and lower electrode plates.
[0010] Furthermore, the plasma generating unit includes an electrically connected plasma generator and a voltage regulator, the plasma generator is provided with an upper electrode terminal, a lower electrode terminal and a frequency modulation knob, the upper electrode terminal is electrically connected to the upper electrode terminal post, the lower electrode terminal is electrically connected to the lower electrode terminal post; the voltage regulator is provided with a voltage modulation knob.
[0011] Furthermore, the circulating water heating unit includes a circulating water tank, a water inlet pipe flowing through one side of the plasma reaction chamber, and a return pipe flowing through the other side of the plasma reaction chamber. The circulating water tank is provided with a circulating water controller, a circulating water tank outlet, and a circulating water tank return port. The two ends of the water inlet pipe are respectively a water inlet pipe inlet and a water inlet pipe outlet. The two ends of the return pipe are respectively a return pipe inlet and a return pipe outlet. The circulating water tank outlet is connected to the water inlet of the water inlet pipe, the water inlet pipe outlet is connected to the return pipe inlet, and the return pipe outlet is connected to the circulating water tank return port.
[0012] Furthermore, the electric heating unit includes an electric heating controller and an electric heating rod for heating the plasma reaction chamber, and the electric heating controller is electrically connected to the electric heating rod through a cable.
[0013] Furthermore, the plasma reaction chamber is sealed with a quartz cover plate.
[0014] Furthermore, the shape of the plasma reaction chamber is circular, square or rectangular, and the shapes of the upper and lower electrode plates are also correspondingly set to be circular, square or rectangular.
[0015] The thermocouple is used to monitor the plasma discharge reaction temperature in real time and display it through a temperature display instrument.
[0016] The discharge area of the upper and lower electrode plates can be between 1000-6400mm according to the electrode shape. 2 The diameter is preferably 60-80 mm and the discharge area is 2827.4-5026.5 mm. 2 Circular discharge electrode plate;
[0017] The materials of the upper and lower electrode plates can be stainless steel, pure copper, silver-plated and gold-plated; the discharge gap can be adjusted within the range of 0.5-5cm; preferably, stainless steel discharge plates are used, and the discharge gap is adjusted to 1.5-2cm.
[0018] When the reaction is required in the low temperature range, the circulating water controller is adjusted to set the circulating water flow rate to 0-20 L / min and the circulating water temperature to -5-100°C. Preferably, the circulating water flow rate is 2-5 L / min and the circulating water temperature is 0-15°C.
[0019] When a reaction in a high temperature range is required, the plasma reaction chamber is heated by an electric heating rod, and the reaction temperature is adjusted to 200-600°C by an electric heating controller. Preferably, the high temperature reaction range is 250-350°C.
[0020] In the specific application process, the substance to be reacted (gas or liquid, etc.) flows into the feed pipe after the flow is controlled by an external mass flow meter or precision injection pump, and the substance after the reaction (gas or liquid, etc.) flows into the detection equipment from the discharge pipe.
[0021] In the specific application process, the plasma discharge frequency is adjusted to 0-50kHz by the frequency knob, preferably, the discharge frequency is set to 10-20kHz; the plasma discharge voltage is adjusted to 0-30kV by the voltage knob, preferably, the discharge voltage is set to 5-15kV.
[0022] Beneficial effects of the utility model:
[0023] 1) The utility model realizes that the temperature of the plasma reaction is adjustable and controllable. When a low-temperature reaction is required, the temperature of the plasma reaction chamber is precisely controlled by controlling the circulating water flow rate and the circulating water temperature; when a high-temperature reaction is required, the plasma reaction chamber is heated by an electric heating rod. At the same time, the water inlet pipe and the water return pipe arranged on both sides of the discharge area can avoid the influence of the contact of the non-uniform medium (reaction chamber, water, reaction atmosphere) on the discharge stability, which is conducive to controlling the experimental variables and reducing the experimental errors.
[0024] 2) The utility model can control the discharge gap by adjusting the distance between the upper and lower electrode plates, thereby achieving control of the electric field strength, and is used to explore the reaction performance under different discharge conditions, which is conducive to finding the best reaction condition.
[0025] 3) The utility model realizes precise control of discharge parameters by switching between different plate shapes such as round, square, rectangular, and different plate materials such as stainless steel, copper, and silver-plated, thereby improving the repeatability and accuracy of the experiment.
[0026] 4) The utility model is conducive to maximizing the use of discharge energy by rationally designing the shape and size of the plasma reaction chamber and matching it with the shape and size of the electrode plate. At the same time, unlike the conventional dielectric barrier discharge reactor which surrounds the central electrode, the catalyst placement and removal process is simplified and the experimental operation is optimized. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The utility model is further described below in conjunction with the accompanying drawings and embodiments.
[0028] Figure 1 It is a schematic diagram of a preferred embodiment of the utility model;
[0029] Figure 2 It is a reaction flow chart of the utility model;
[0030] Figure 3 This is a schematic diagram of a circulating water tank;
[0031] Figure 4 is a schematic diagram of a plasma generating unit;
[0032] Figure 5 is a schematic diagram of the plasma sub-reaction chamber of Example 1;
[0033] Figure 6 is a schematic diagram of an electrode unit of Example 1;
[0034] Figure 7 is a plasma discharge voltage and current signal diagram in Example 1 of the present invention;
[0035] Figure 8is the plasma discharge Lissajous figure in Example 1 of the present invention;
[0036] Fig. 9 is a Raman spectrum of the catalyst material before and after plasma discharge treatment in Example 1 of the present invention;
[0037] Fig.10 is a discharge parameter diagram obtained by using discharge electrodes of different materials in Example 1 of the present invention;
[0038] Fig.11 is a schematic diagram of a plasma sub-reaction chamber of Example 2;
[0039] Fig.12 is a schematic diagram of an electrode unit of Example 2;
[0040] Fig.13 is a schematic diagram of a plasma sub-reaction chamber of Example 3;
[0041] Fig.14 Schematic diagram of the electrode unit of Example 3. DETAILED DESCRIPTION
[0042] In order to further explain the technical means and effects adopted by the utility model to achieve the predetermined utility model purpose, the specific implementation methods, structures, features and effects of the utility model application are described in detail below in conjunction with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures, or characteristics in one or more embodiments may be combined in any suitable form.
[0043] In the description of the present invention, it should be clarified that the terms "vertical", "lateral", "longitudinal", "center", "opposite", "vertical", "upper", "lower" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are merely for the convenience of describing the present invention. They do not mean that the device or element referred to must have a specific direction or position, and therefore cannot be understood as a limitation on the present invention.
[0044] like Figures 1 to 4 As shown, the utility model discloses a dielectric barrier discharge plasma experimental device, comprising a plasma reaction chamber 11, an electrode unit for applying voltage to the plasma reaction chamber, and a plasma generating unit electrically connected to the electrode unit; the plasma reaction chamber is provided with a feed pipe 3 and a discharge pipe 9, a thermocouple 6 is provided in the plasma reaction chamber, and also comprises a temperature display 5, a circulating water heating unit for realizing the reaction of the plasma reaction chamber in a low temperature range, and an electric heating unit for realizing the reaction of the plasma reaction chamber in a high temperature range, and the temperature display is electrically connected to the thermocouple.
[0045] The electrode unit includes an electrode mounting seat 13, an upper electrode plate 16, an upper electrode terminal 17, a lower electrode plate 15 and a lower electrode terminal 14. The upper electrode plate, the upper electrode terminal, the lower electrode plate and the lower electrode terminal are all mounted on the electrode mounting seat. The upper electrode plate is electrically connected to the upper electrode terminal, and the lower electrode plate is electrically connected to the lower electrode terminal. The plasma reaction chamber is arranged between the upper and lower electrode plates.
[0046] The plasma generating unit comprises an electrically connected plasma generator 22 and a voltage regulator 26. The plasma generator is provided with an upper electrode terminal 21, a lower electrode terminal 23 and a frequency modulation knob 24. The upper electrode terminal is electrically connected to the upper electrode terminal post, and the lower electrode terminal is electrically connected to the lower electrode terminal post. The voltage regulator is provided with a voltage modulation knob 25.
[0047] The circulating water heating unit includes a circulating water tank 20, a water inlet pipe 7 flowing through one side of the plasma reaction chamber, and a return pipe 12 flowing through the other side of the plasma reaction chamber. The circulating water tank is provided with a circulating water controller, a circulating water tank outlet 18, and a circulating water tank return port 19. The two ends of the water inlet pipe are respectively a water inlet pipe inlet 8 and a water inlet pipe outlet 4, and the two ends of the return pipe are respectively a return pipe inlet 2 and a return pipe outlet 10. The circulating water tank outlet is connected to the water inlet of the water inlet pipe, the water inlet pipe outlet is connected to the water inlet of the return pipe, and the return pipe outlet is connected to the return port of the circulating water tank.
[0048] The electric heating unit includes an electric heating controller 29 and an electric heating rod 27 for heating the plasma reaction chamber. The electric heating controller is electrically connected to the electric heating rod via a cable 28 .
[0049] The plasma reaction chamber is sealed with a quartz cover plate 1. The shape of the plasma reaction chamber is circular, square or rectangular, and the shapes of the upper and lower electrode plates are also correspondingly set to be circular, square or rectangular.
[0050] The specific usage process is as follows:
[0051] 1) Connect the gas (liquid) pipeline required for the reaction to the feed pipe 9, and connect the discharge pipe 3 to the testing equipment;
[0052] 2) Spread the catalyst flat in the plasma reaction chamber 11, put appropriate amounts of quartz wool in the feed pipe 9 and the discharge pipe 3 to prevent the catalyst from flowing out, and cover with a quartz cover plate 1;
[0053] 3) Place the plasma reaction chamber between the upper electrode plate 16 and the lower electrode plate 15 of suitable discharge area, adjust to an appropriate discharge gap and fix it;
[0054] 4) Connect the water inlet of the water inlet pipe to the water outlet 18 of the circulating water tank through a rubber tube, and connect the water outlet 10 of the return pipe to the water return port 19 of the circulating water tank through a rubber tube; if the reaction needs to be carried out in a high temperature range, start the heating rod;
[0055] 5) Connecting the upper electrode terminal 17 to the upper electrode terminal 21, and connecting the lower electrode terminal 14 to the lower electrode terminal 23;
[0056] 6) Connect the temperature control system and the plasma discharge system to the power supply, start the circulating water heating unit and adjust it to the temperature required for the reaction; start the plasma generator 22, adjust the voltage to the required discharge voltage through the voltage adjustment knob 25, and adjust the frequency to the required discharge frequency through the frequency adjustment knob 24;
[0057] 7) Introduce reaction gas (liquid) to start testing.
[0058] The following is further described with specific examples:
[0059] Example 1
[0060] like Figure 5 and Figure 6 As shown, the plasma reaction chamber of this embodiment is circular, and correspondingly, the upper and lower electrode plates are also circular.
[0061] This embodiment reacts in a low temperature range, and the temperature of the plasma reaction chamber is controlled by a circulating water heating unit to keep the reaction temperature at 50°C.
[0062] The plasma generator of this embodiment adjusts the plasma discharge frequency to 10kHz through the frequency adjustment knob 24; adjusts the plasma discharge voltage to 50V through the voltage adjustment knob 25, and calculates the discharge power to be 20W through the output electrical signal of the external oscilloscope.
[0063] The electrode plates of this embodiment can be made of different materials. The discharge parameters of different materials are as follows: Fig.10 shown.
[0064] The catalyst required for the reaction of this embodiment is evenly spread and placed on the bottom surface of the plasma reaction chamber 11; the propane and nitrogen used for the reaction are connected to the feed pipe 9 through a rubber tube after the flow rate is controlled by an external flow meter; the propylene, hydrogen and other gases generated after the reaction are passed into the gas chromatograph through a rubber tube connected to the discharge pipe 3 for analysis, and finally the propane conversion rate and propylene / hydrogen selectivity are obtained by calculation.
[0065] Plasma discharge parameters are shown in Figure 7 , Figure 8 The catalyst was tested by Raman spectroscopy before and after the reaction. The results are shown in Fig. 9, and found that after plasma discharge treatment, the catalyst formed new functional groups, which helped to catalyze propane dehydrogenation and improve the reaction efficiency.
[0066] Example 2
[0067] like Fig.11 and Fig.12 As shown, the plasma reaction chamber of this embodiment is square, and correspondingly, the upper and lower electrode plates are also square.
[0068] This embodiment reacts in a high temperature range, and the temperature of the plasma reaction chamber is controlled by an electric heating unit to keep the reaction temperature at 750°C.
[0069] The plasma generator of this embodiment adjusts the plasma discharge frequency to 15kHz through the frequency adjustment knob 24; adjusts the plasma discharge voltage to 50V through the voltage adjustment knob 25, and calculates the discharge power to be 25W through the output electrical signal of the external oscilloscope.
[0070] The catalyst required for the reaction in this embodiment is evenly spread and placed on the bottom surface of the plasma reaction chamber 11; the methane and nitrogen used for the reaction are connected to the feed pipe 9 through a rubber tube after the flow rate is controlled by an external flow meter; the propylene, hydrogen and other gases generated after the reaction are passed into the gas chromatograph through a rubber tube connected to the discharge pipe 3 for analysis, and finally the methane conversion rate, hydrogen concentration and hydrogen yield are obtained by calculation.
[0071] Example 3
[0072] like Fig.13 and Fig.14 As shown, the plasma reaction chamber of this embodiment is rectangular, and accordingly, the upper and lower electrode plates are also rectangular.
[0073] This embodiment reacts in a high temperature range, and the temperature of the plasma reaction chamber is controlled by an electric heating unit to keep the reaction temperature at 750°C.
[0074] The plasma generator of this embodiment adjusts the plasma discharge frequency to 20kHz through the frequency adjustment knob 24; adjusts the plasma discharge voltage to 50V through the voltage adjustment knob 25, and calculates the discharge power to be 30W through the output electrical signal of the external oscilloscope.
[0075] The catalyst required for the reaction of this embodiment is evenly spread and placed on the bottom surface of the plasma discharge reaction chamber 11; the methane and nitrogen used for the reaction are connected to the feed pipe 9 through a rubber tube after the flow rate is controlled by an external flow meter; the propylene, hydrogen and other gases generated after the reaction are passed into the gas chromatograph through a rubber tube connected to the discharge pipe 3 for analysis, and finally the methane conversion rate, hydrogen concentration and hydrogen yield are obtained by calculation.
[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.
Claims
1. A dielectric barrier discharge plasma experimental device, characterized in that: The invention comprises a plasma reaction chamber, an electrode unit for applying voltage to the plasma reaction chamber, and a plasma generating unit electrically connected to the electrode unit; the plasma reaction chamber is provided with a feed pipe and a discharge pipe, a thermocouple is provided in the plasma reaction chamber, and further comprises a temperature display, a circulating water heating unit for realizing reaction in a low temperature range of the plasma reaction chamber, and an electric heating unit for realizing reaction in a high temperature range of the plasma reaction chamber, wherein the temperature display is electrically connected to the thermocouple.
2. The dielectric barrier discharge plasma experimental device according to claim 1, characterized in that: The electrode unit includes an electrode mounting seat, an upper electrode plate, an upper electrode terminal, a lower electrode plate and a lower electrode terminal. The upper electrode plate, the upper electrode terminal, the lower electrode plate and the lower electrode terminal are all mounted on the electrode mounting seat. The upper electrode plate is electrically connected to the upper electrode terminal, and the lower electrode plate is electrically connected to the lower electrode terminal. The plasma reaction chamber is arranged between the upper and lower electrode plates.
3. The dielectric barrier discharge plasma experimental device according to claim 2, characterized in that: The plasma generating unit comprises an electrically connected plasma generator and a voltage regulator, wherein the plasma generator is provided with an upper electrode terminal, a lower electrode terminal and a frequency modulation knob, the upper electrode terminal is electrically connected to an upper electrode terminal post, and the lower electrode terminal is electrically connected to a lower electrode terminal post; and the voltage regulator is provided with a voltage modulation knob.
4. The dielectric barrier discharge plasma experimental device according to claim 3, characterized in that: The circulating water heating unit comprises a circulating water tank, a water inlet pipe flowing through one side of the plasma reaction chamber, and a water return pipe flowing through the other side of the plasma reaction chamber. The circulating water tank is provided with a circulating water controller, a circulating water tank outlet, and a circulating water tank return port. The two ends of the water inlet pipe are respectively a water inlet pipe inlet and a water inlet pipe outlet. The two ends of the return pipe are respectively a return pipe inlet and a return pipe outlet. The circulating water tank outlet is communicated with the water inlet of the water inlet pipe, the water inlet pipe outlet is communicated with the water inlet of the return pipe, and the return pipe outlet is communicated with the return water tank return port.
5. The dielectric barrier discharge plasma experimental device according to claim 4, characterized in that: The electric heating unit comprises an electric heating controller and an electric heating rod for heating the plasma reaction chamber, and the electric heating controller is electrically connected to the electric heating rod through a cable.
6. The dielectric barrier discharge plasma experimental device according to claim 5, characterized in that: The plasma reaction chamber is sealed with a quartz cover plate.
7. The dielectric barrier discharge plasma experimental device according to claim 6, characterized in that: The shape of the plasma reaction chamber is circular, square or rectangular; the shapes of the upper and lower electrode plates are also correspondingly set to be circular, square or rectangular.