Device and method for preparing hydrogen peroxide by combining plasma with micro-droplets

Abstract

The invention discloses a device for preparing hydrogen peroxide by combining plasma with micro-droplets and a preparation method, belongs to the technical field of hydrogen peroxide synthesis, and realizes the technical effect of preparing hydrogen peroxide by catalyzing the micro-droplets through the plasma by combining sheath gas spray and a plasma gliding arc reactor. Oxygen is introduced as a reaction substance, and the oxygen-containing gas promotes generation of. OH, so that the concentration of the product hydrogen peroxide is improved. Sliding arc discharge has the characteristics of good thermal stability, low maintaining voltage, high luminance and high current density, and hydrogen peroxide is a main reaction substance for discharge of a sliding arc reactor.

Description

Technical Field

[0001] The invention relates to the technical field of hydrogen peroxide synthesis, and in particular to a device and a method for preparing hydrogen peroxide by combining plasma with micro-droplets. Background Art

[0002] As an oxidant, hydrogen peroxide has the highest active oxygen content among existing industrial oxidants, which can reach 47.1% w / w. The reduction product is water. It is pollution-free during production and use and has a variety of applications in the fields of industry and environmental protection. It can improve the combustion efficiency of rocket fuel or be used to replace some traditional and more polluting chemicals, thereby helping to reduce carbon emissions to a certain extent. For example, hydrogen peroxide is used as a cleaning agent and bleaching agent to replace chemicals containing chlorine. These chlorine compounds may produce harmful byproducts and increase greenhouse gas emissions during production and use. For the purification of wastewater, it helps decompose organic pollutants, thereby reducing the impact on the environment and reducing the carbon emissions that may be generated during the treatment process.

[0003] At present, the common green methods for producing hydrogen peroxide mainly include hydrogen and oxygen combination to generate hydrogen peroxide, photocatalysis, and electrocatalysis. However, the concentration of hydrogen peroxide they generate is much lower than the concentration of hydrogen peroxide mother liquor produced by the anthraquinone method. When hydrogen peroxide is produced by the anthraquinone method, the production process is mainly to hydrogenate anthraquinone organic compounds to obtain hydrogenated anthraquinone, which is then oxidized to obtain anthraquinone and hydrogen peroxide mother liquor. The initial mass concentration of hydrogen peroxide is 0.8% to 1.9%. It is necessary to undergo a series of subsequent extraction, distillation, purification and other operations to make the concentration of hydrogen peroxide reach more than 30%, and then reach the concentration of hydrogen peroxide we use in daily life.

[0004] However, the above process is heavily dependent on transportation and has storage instability problems, causing air pollution. In addition, the repeated use of anthraquinone organic solvents in the entire process of producing hydrogen peroxide complicates the process. The mass transfer resistance at the interface makes the reactor inefficient. In addition, the production process requires expensive palladium catalysts and a large amount of energy input. This series of shortcomings is not conducive to the concept of low-carbon and environmental protection.

[0005] The spontaneous generation of hydrogen peroxide from water is due to the strong electric field on the surface of water droplets, and plasma discharge can form a strong electric field on the droplets, thereby causing water to form hydrogen peroxide. However, existing plasma discharge technologies, such as dielectric barrier discharge, glow discharge and corona discharge, all face the problem of incompatibility with droplets. The electrodes of dielectric barrier discharge are relatively close, which will cause the droplets to adsorb on the electrode surface. Glow discharge requires precise temperature control. Corona discharge has a small area and high temperature, which is not conducive to the spontaneous synthesis of hydrogen peroxide from water. Summary of the invention

[0006] The present invention provides a device and a method for preparing hydrogen peroxide by combining plasma with micro-droplets, which effectively solves the technical problems that although a relatively high concentration of hydrogen peroxide can be obtained by preparing hydrogen peroxide by an anthraquinone method, the energy consumption is high and it is not conducive to low-carbon and environmental protection, the existing plasma discharge technology is incompatible with micro-droplets, and water cannot spontaneously synthesize hydrogen peroxide. Meanwhile, a simple, green and efficient device and method for synthesizing hydrogen peroxide are provided, and the concentration of the prepared hydrogen peroxide reaches a comparable order of magnitude with the concentration of the hydrogen peroxide mother liquor by the anthraquinone method.

[0007] The first object of the present invention is to provide a device for preparing hydrogen peroxide by combining plasma with micro-droplets, comprising:

[0008] A sheath air spray device, the sheath air spray device comprising an air inlet, a water inlet and a spray outlet;

[0009] A plasma reactor, which is arranged below the sheath gas spray device, and the nozzle extends into the cavity of the plasma reactor;

[0010] Two electrodes, including a first electrode and a second electrode, are symmetrically arranged in the cavity of the plasma reactor, there is a gap between the first electrode and the second electrode, and the nozzle is located above the gap;

[0011] Oxygen is introduced through the air inlet, water is injected through the water inlet, and micro droplets are generated through the nozzle. When high voltage is applied to the two electrodes, the oxygen generated by the nozzle flows through the electrodes to perform arc discharge, and the micro droplets ejected by the electrode arc discharge are catalyzed to obtain hydrogen peroxide.

[0012] As a preferred implementation, the size of the interval is 0.5 mm to 3 mm.

[0013] As a preferred implementation, the distance between the nozzle and the interval is 1.5 mm to 5 mm.

[0014] As a preferred embodiment, a condensed water inlet and a condensed water outlet are provided on the side wall of the plasma reactor.

[0015] As a preferred embodiment, the side wall of the plasma reactor is also provided with an exhaust port.

[0016] The second object of the present invention is to provide a method for preparing hydrogen peroxide by using the above-mentioned plasma combined with micro-droplets to prepare hydrogen peroxide, comprising the following steps:

[0017] Passing oxygen through the air inlet and water through the water inlet through the syringe pump into the sheath gas spray device, and processing through the sheath gas spray device to obtain micro droplets and compressed oxygen through the nozzle;

[0018] A pulse plasma generator is used to apply voltage to two electrodes, and the compressed oxygen flows through the gap between the first electrode and the second electrode to generate arc discharge, catalyze the micro droplets, and synthesize hydrogen peroxide.

[0019] As a preferred embodiment, the voltage inputted by the plasma generator to the two electrodes is 1.5 kV to 4.5 kV, the pulse width is 1 μs to 5 μs, and the frequency is 10 kHz to 30 kHz.

[0020] As a preferred implementation, the flow rate of the oxygen is 1 L / min to 5 L / min.

[0021] As a preferred embodiment, the micro-droplets are formed by pneumatic air pressure method, using the pressure of external high-speed gas to provide shear force to form micro-droplets from the flowing liquid, and the flow rate of the water is 20mL / h to 30mL / h.

[0022] As a preferred embodiment, the operating temperature of the sheath air spray device is 10°C to 35°C.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The device and preparation method for preparing hydrogen peroxide by plasma combined with micro-droplets provided by the present invention combine sheath gas spray and plasma sliding arc reactor to achieve the technical effect of plasma catalytic micro-droplet preparation of hydrogen peroxide. The present invention combines sheath gas spray with sliding arc plasma discharge, and the sheath gas spray realizes the generation of micro-droplets, and the micro-droplets are transported to the sliding arc plasma discharge area, and the reaction of water splitting into hydrogen peroxide occurs in the sliding arc discharge area. By introducing oxygen as a reactant, the oxygen-containing gas promotes the generation of OH, thereby increasing the concentration of the product hydrogen peroxide. The sliding arc discharge has the characteristics of good thermal stability, low maintenance voltage, high luminous brightness, and high current density, and hydrogen peroxide is the main reactant of the sliding arc reactor discharge.

[0025] The present invention determines the reaction time by adjusting the amount of liquid injected by the injection pump, that is, the reaction time is controllable and generally only about 10 minutes. The oxygen flow rate is adapted to both the sheath gas spray flow rate and the gas flow rate of the sliding arc discharge. The lid of the plasma reactor of the present invention is detachable and adjustable, and the shape of the arc can be observed during the discharge process to judge the discharge effect.

[0026] The present invention has the advantages of being environmentally friendly, zero carbon emission, low cost, simple raw materials, innovative technology, high safety and short reaction time. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic structural diagram of a device for preparing hydrogen peroxide by combining plasma with micro-droplets according to the present invention.

[0028] Figure 2 This is a photo of the sliding arc discharge at a gas flow rate of 1 L / min in the present invention.

[0029] Figure 3 This is a photo of the sliding arc discharge at a gas flow rate of 2 L / min in the present invention.

[0030] Figure 4 This is a photo of the sliding arc discharge at a gas flow rate of 3 L / min in the present invention.

[0031] Figure 5 This is a photo of the sliding arc discharge at a gas flow rate of 4 L / min in the present invention.

[0032] Figure 6 This is a photo of the sliding arc discharge at a gas flow rate of 5 L / min in the present invention.

[0033] Figure 7 These are the atomized microdroplets observed under an optical microscope in the present invention.

[0034] Figure 8 This is a voltage diagnostic diagram of the gliding arc plasma discharge under the condition of a gas flow rate of 4 L / min in the present invention.

[0035] Fig. 9 This is a comparison chart of hydrogen peroxide concentration under changing gas atmospheres of the present invention, wherein oxygen is Example 1, nitrogen is Comparative Example 1, and air is Comparative Example 2.

[0036] Description of reference numerals:

[0037] 1. Sheath gas spray device, 11. Air inlet, 12. Water inlet, 13. Nozzle, 2. Plasma reactor, 21. Condensate water inlet, 22. Condensate water outlet, 23. Exhaust port, 31. First electrode, 32. Second electrode, 4. Pulse plasma generator, 5. Injection pump. DETAILED DESCRIPTION

[0038] In order to enable those skilled in the art to better understand the technical solution of the present invention and implement it, the present invention is further described below in conjunction with specific embodiments and drawings, but the embodiments are not intended to limit the present invention. The following test methods and detection methods, unless otherwise specified, are conventional methods; the reagents and raw materials, unless otherwise specified, are commercially available.

[0039] In view of the above mentioned background technology of the present invention: First, hydrogen peroxide is generated by combining hydrogen and oxygen, and hydrogen peroxide is produced by photocatalysis or electrocatalysis. Although it conforms to the concept of green environmental protection, the concentration of hydrogen peroxide generated by the above method is much lower than the concentration of hydrogen peroxide mother liquor by the anthraquinone method; Second, when hydrogen peroxide is produced by the anthraquinone method, it is heavily dependent on transportation and there is a problem of unstable storage, which causes air pollution, and the repeated use of anthraquinone organic solvent in the whole process of producing hydrogen peroxide complicates the process, and the mass transfer resistance of the interface makes the reactor inefficient, and expensive palladium catalysts and a large amount of energy input are required in the production process; Third, plasma discharge is used to form a strong electric field on micro-droplets, so that water generates hydrogen peroxide, but existing plasma discharge technologies, such as dielectric barrier discharge, glow discharge and corona discharge, will face the problem of incompatibility with micro-droplets. The dielectric barrier discharge electrode spacing is relatively close, which will cause the micro-droplets to be adsorbed on the electrode surface, and the glow discharge requires precise temperature control. The corona discharge area is small and the temperature is high, which is not conducive to the spontaneous synthesis of hydrogen peroxide by water. Based on the above existing technical problems, the present invention provides a device and a preparation method for preparing hydrogen peroxide by combining plasma with micro-droplets.

[0040] The technical solution provided by the present invention is described in detail below.

[0041] The present invention first provides a device for preparing hydrogen peroxide by combining plasma with micro-droplets, such as Figure 1 As shown, including:

[0042] A sheath air spray device 1, wherein the sheath air spray device 1 comprises an air inlet 11, a water inlet 12 and a nozzle 13;

[0043] A plasma reactor 2, which is arranged below the sheath gas spray device 1, and the nozzle 13 extends into the cavity of the plasma reactor 2;

[0044] Two electrodes, including a first electrode 31 and a second electrode 32, are symmetrically arranged in the cavity of the plasma reactor 2, and there is a gap between the first electrode 31 and the second electrode 32, and the nozzle 13 is located above the gap;

[0045] Oxygen is introduced through the air inlet 11, water is injected through the water inlet 12, and micro droplets are generated through the nozzle 13. When high voltage is applied to the two electrodes, the oxygen generated by the nozzle 13 flows through the electrodes for arc discharge, and hydrogen peroxide is obtained by catalyzing the ejected droplets through the electrode arc discharge.

[0046] In order to make the two symmetrical electrodes produce arc discharge, the size of the interval is 0.5 mm to 3 mm, and the optimal interval size is 1.5 mm.

[0047] In order to ensure that micro droplets are generated when the electrode is arcing and discharging, the distance between the nozzle 13 and the interval is 1.5 mm to 5 mm, and the optimal interval distance is 3.5 mm.

[0048] In order to reduce the reaction temperature in the plasma generator, a condensed water inlet 21 and a condensed water outlet 22 are provided on the side wall of the plasma reactor 2 .

[0049] In order to balance the gas pressure in the plasma reactor 2, the side wall of the plasma reactor 2 is also provided with an exhaust port 23. If the exhaust port is not provided, the pressure in the plasma reactor 2 is too high, which will break the upper cover of the plasma reactor 2 and affect the normal progress of the reaction.

[0050] The present invention also provides a method for preparing hydrogen peroxide using the above-mentioned plasma combined with micro-droplet hydrogen peroxide preparation device, comprising the following steps:

[0051] The oxygen is introduced into the sheath gas spray device 1 through the gas inlet 11 and the water is introduced into the sheath gas spray device 1 through the water inlet 12 through the injection pump 5, and the micro droplets and compressed oxygen are obtained through the nozzle 13 after being processed by the sheath gas spray device 1;

[0052] A pulse plasma generator 4 is used to apply voltage to the two electrodes, and the compressed oxygen flows through the gap between the first electrode 31 and the second electrode 32 to generate arc discharge, catalyze the micro droplets, and synthesize hydrogen peroxide.

[0053] In order to ensure the concentration of the product hydrogen peroxide, the voltage input to the two electrodes by the plasma generator is 1.5kV to 4.5kV, the pulse width is 1 to 5μs, and the frequency is 10kHz to 30kHz. Changing the voltage, pulse width and frequency will affect the concentration of hydrogen peroxide. When the voltage is too high, greater than 4.5kV, the plasma discharge is enhanced, but the tendency of hydrogen peroxide decomposition also becomes greater, which will reduce the concentration of hydrogen peroxide. When the voltage is lower than 1.5kV, no discharge occurs. For the two parameters of pulse width and frequency, as with the voltage, values ​​lower or higher than the range here will affect the concentration of hydrogen peroxide.

[0054] In order to further increase the concentration of hydrogen peroxide, the oxygen, i.e., the gas ejected from the sheath gas spray nozzle, has a flow rate of 1 L / min to 5 L / min. If the flow rate is too low, less than 1 L / min, the intensity of the plasma discharge is low, the water activation effect is low, and the concentration of hydrogen peroxide is low. If the flow rate is too high, greater than 5 L / min, the residence time of the micro-droplets generated by the sheath gas spray flowing through the plasma discharge zone is too short, the gas does not have time to activate, and the oxygen does not have time to generate hydrogen peroxide.

[0055] In order to match the oxygen flow rate with the water flow rate, thereby further increasing the concentration of hydrogen peroxide, the microdroplets are formed by pneumatic air pressure method, using the pressure of external high-speed gas to provide shear force, so that the flowing liquid forms microdroplets, and the water flow rate is 20mL / h to 30mL / h. If the water flow rate is lower than 20mL / h, the number of microdroplets produced is small, the reaction is not sufficient, and the concentration of hydrogen peroxide is reduced. If the water flow rate is higher than 30mL / h, the size of the microdroplets is too large, which reduces the contact area between the microdroplets and the plasma, and also reduces the concentration of hydrogen peroxide.

[0056] In order to ensure the generation rate of hydrogen peroxide, the operating temperature of the sheath gas spray device 1 is 10° C. to 35° C. If the temperature is lower than 10° C., the rate of generating hydrogen peroxide decreases because the reaction rate decreases with the decrease in temperature. If the temperature is higher than 35° C., the decomposition tendency of hydrogen peroxide increases, which also causes the generation rate of hydrogen peroxide to decrease.

[0057] The technical effects of this case are described below through specific embodiments.

[0058] Example 1

[0059] The device for preparing hydrogen peroxide by combining plasma with micro-droplets comprises:

[0060] The sheath air spray device 1 comprises an air inlet 11 , a water inlet 12 and a nozzle 13 .

[0061] The plasma reactor 2 is arranged below the sheath gas spray device 1, and the nozzle 13 extends into the cavity of the plasma reactor 2; the side wall of the plasma reactor 2 is provided with a condensed water inlet 21 and a condensed water outlet 22, and the side wall of the plasma reactor 2 is also provided with an exhaust port 23.

[0062] Two electrodes, including a first electrode 31 and a second electrode 32, are symmetrically arranged in the cavity of the plasma reactor 2. The interval between the first electrode 31 and the second electrode 32 is set to 1.5 mm, and the nozzle 13 is arranged above the interval at a distance of 3.5 mm.

[0063] Oxygen is introduced through the air inlet 11, water is injected through the water inlet 12, and micro droplets are generated through the nozzle 13. When high voltage is applied to the two electrodes, the oxygen generated by the nozzle 13 flows through the electrodes to perform arc discharge, and the electrode arc discharge catalyzes the ejected droplets to obtain hydrogen peroxide.

[0064] The method for preparing hydrogen peroxide using the above plasma combined with micro-droplet hydrogen peroxide preparation device comprises the following steps:

[0065] Oxygen with a flow rate of 5 L / min is passed through the air inlet 11, and water with a flow rate of 25 mL / h is passed through the syringe pump 5 through the water inlet 12 into the sheath gas spray device 1. Through the sheath gas spray device 1, a pneumatic air pressure method is used at 25° C. to provide shear force with the pressure of external high-speed gas, so that the flowing liquid forms micro-droplets and compressed oxygen through the nozzle 13;

[0066] A pulse plasma generator 4 is used to apply a 2.5 kV voltage to the two electrodes, with a pulse width of 2.2 μs and a frequency of 20 kHz. The compressed oxygen flows through the gap between the first electrode 31 and the second electrode 32 to generate arc discharge, catalyze the micro-droplets, and synthesize hydrogen peroxide.

[0067] Example 2

[0068] The device for preparing hydrogen peroxide by combining plasma with micro-droplets comprises:

[0069] The sheath air spray device 1 comprises an air inlet 11 , a water inlet 12 and a nozzle 13 .

[0070] The plasma reactor 2 is arranged below the sheath gas spray device 1, and the nozzle 13 extends into the cavity of the plasma reactor 2; the side wall of the plasma reactor 2 is provided with a condensed water inlet 21 and a condensed water outlet 22, and the side wall of the plasma reactor 2 is also provided with an exhaust port 23.

[0071] Two electrodes, including a first electrode 31 and a second electrode 32, are symmetrically arranged in the cavity of the plasma reactor 2. The interval between the first electrode 31 and the second electrode 32 is set to 1.5 mm, and the nozzle 13 is arranged above the interval at a distance of 3.5 mm.

[0072] Oxygen is introduced through the air inlet 11, water is injected through the water inlet 12, and micro droplets are generated through the nozzle 13. When high voltage is applied to the two electrodes, the oxygen generated by the nozzle 13 flows through the electrodes to perform arc discharge, and the electrode arc discharge catalyzes the ejected droplets to obtain hydrogen peroxide.

[0073] The method for preparing hydrogen peroxide using the above plasma combined with micro-droplet hydrogen peroxide preparation device comprises the following steps:

[0074] Oxygen with a flow rate of 4 L / min is passed through the air inlet 11, and water with a flow rate of 25 mL / h is passed through the syringe pump 5 through the water inlet 12 into the sheath gas spray device 1. Through the sheath gas spray device 1, a pneumatic air pressure method is used at 25° C. to provide shear force with the pressure of external high-speed gas, so that the flowing liquid forms micro-droplets and compressed oxygen through the nozzle 13;

[0075] A pulse plasma generator 4 is used to apply a 2.5 kV voltage to the two electrodes, with a pulse width of 2.2 μs and a frequency of 20 kHz. The compressed oxygen flows through the gap between the first electrode 31 and the second electrode 32 to generate arc discharge, catalyze the micro-droplets, and synthesize hydrogen peroxide.

[0076] Example 3

[0077] The device for preparing hydrogen peroxide by combining plasma with micro-droplets comprises:

[0078] The sheath air spray device 1 comprises an air inlet 11 , a water inlet 12 and a nozzle 13 .

[0079] The plasma reactor 2 is arranged below the sheath gas spray device 1, and the nozzle 13 extends into the cavity of the plasma reactor 2; the side wall of the plasma reactor 2 is provided with a condensed water inlet 21 and a condensed water outlet 22, and the side wall of the plasma reactor 2 is also provided with an exhaust port 23.

[0080] Two electrodes, including a first electrode 31 and a second electrode 32, are symmetrically arranged in the cavity of the plasma reactor 2. The interval between the first electrode 31 and the second electrode 32 is set to 1.5 mm, and the nozzle 13 is arranged above the interval at a distance of 3.5 mm.

[0081] Oxygen is introduced through the air inlet 11, water is injected through the water inlet 12, and micro droplets are generated through the nozzle 13. When high voltage is applied to the two electrodes, the oxygen generated by the nozzle 13 flows through the electrodes to perform arc discharge, and the electrode arc discharge catalyzes the ejected droplets to obtain hydrogen peroxide.

[0082] The method for preparing hydrogen peroxide using the above plasma combined with micro-droplet hydrogen peroxide preparation device comprises the following steps:

[0083] Oxygen with a flow rate of 3L / min is passed through the air inlet 11, and water with a flow rate of 25mL / h is passed through the syringe pump 5 through the water inlet 12 into the sheath gas spray device 1. Through the sheath gas spray device 1, a pneumatic air pressure method is used at 25°C to provide shear force with the pressure of external high-speed gas, so that the flowing liquid forms micro-droplets and compressed oxygen through the nozzle 13;

[0084] A pulse plasma generator 4 is used to apply a 2.5 kV voltage to the two electrodes, with a pulse width of 2.2 μs and a frequency of 20 kHz. The compressed oxygen flows through the gap between the first electrode 31 and the second electrode 32 to generate arc discharge, catalyze the micro-droplets, and synthesize hydrogen peroxide.

[0085] Example 4

[0086] The device for preparing hydrogen peroxide by combining plasma with micro-droplets comprises:

[0087] The sheath air spray device 1 comprises an air inlet 11 , a water inlet 12 and a nozzle 13 .

[0088] The plasma reactor 2 is arranged below the sheath gas spray device 1, and the nozzle 13 extends into the cavity of the plasma reactor 2; the side wall of the plasma reactor 2 is provided with a condensed water inlet 21 and a condensed water outlet 22, and the side wall of the plasma reactor 2 is also provided with an exhaust port 23.

[0089] Two electrodes, including a first electrode 31 and a second electrode 32, are symmetrically arranged in the cavity of the plasma reactor 2. The interval between the first electrode 31 and the second electrode 32 is set to 1.5 mm, and the nozzle 13 is arranged above the interval at a distance of 3.5 mm.

[0090] Oxygen is introduced through the air inlet 11, water is injected through the water inlet 12, and micro droplets are generated through the nozzle 13. When high voltage is applied to the two electrodes, the oxygen generated by the nozzle 13 flows through the electrodes to perform arc discharge, and the electrode arc discharge catalyzes the ejected droplets to obtain hydrogen peroxide.

[0091] The method for preparing hydrogen peroxide using the above plasma combined with micro-droplet hydrogen peroxide preparation device comprises the following steps:

[0092] Oxygen with a flow rate of 2L / min is passed through the air inlet 11, and water with a flow rate of 25mL / h is passed through the syringe pump 5 through the water inlet 12 into the sheath gas spray device 1. Through the sheath gas spray device 1, a pneumatic air pressure method is used at 25°C to provide shear force with the pressure of external high-speed gas, so that the flowing liquid forms micro-droplets and compressed oxygen through the nozzle 13;

[0093] A pulse plasma generator 4 is used to apply a 2.5 kV voltage to the two electrodes, with a pulse width of 2.2 μs and a frequency of 20 kHz. The compressed oxygen flows through the gap between the first electrode 31 and the second electrode 32 to generate arc discharge, catalyze the micro-droplets, and synthesize hydrogen peroxide.

[0094] Example 5

[0095] The device for preparing hydrogen peroxide by combining plasma with micro-droplets comprises:

[0096] The sheath air spray device 1 comprises an air inlet 11 , a water inlet 12 and a nozzle 13 .

[0097] The plasma reactor 2 is arranged below the sheath gas spray device 1, and the nozzle 13 extends into the cavity of the plasma reactor 2; the side wall of the plasma reactor 2 is provided with a condensed water inlet 21 and a condensed water outlet 22, and the side wall of the plasma reactor 2 is also provided with an exhaust port 23.

[0098] Two electrodes, including a first electrode 31 and a second electrode 32, are symmetrically arranged in the cavity of the plasma reactor 2. The interval between the first electrode 31 and the second electrode 32 is set to 1.5 mm, and the nozzle 13 is arranged above the interval at a distance of 3.5 mm.

[0099] Oxygen is introduced through the air inlet 11, water is injected through the water inlet 12, and micro droplets are generated through the nozzle 13. When high voltage is applied to the two electrodes, the oxygen generated by the nozzle 13 flows through the electrodes to perform arc discharge, and the electrode arc discharge catalyzes the ejected droplets to obtain hydrogen peroxide.

[0100] The method for preparing hydrogen peroxide using the above plasma combined with micro-droplet hydrogen peroxide preparation device comprises the following steps:

[0101] Oxygen with a flow rate of 1 L / min is passed through the air inlet 11, and water with a flow rate of 25 mL / h is passed through the syringe pump 5 through the water inlet 12 into the sheath gas spray device 1. Through the sheath gas spray device 1, a pneumatic air pressure method is used at 25° C. to provide shear force with the pressure of external high-speed gas, so that the flowing liquid forms micro-droplets and compressed oxygen through the nozzle 13;

[0102] A pulse plasma generator 4 is used to apply a voltage of 1.5 to 4.5 kV to the two electrodes, with a pulse width of 2.2 μs and a frequency of 20 kHz. The compressed oxygen flows through the gap between the first electrode 31 and the second electrode 32 to generate arc discharge, catalyze the micro-droplets, and synthesize hydrogen peroxide.

[0103] In order to further demonstrate the technical effect of the present invention, the present invention also sets a comparative example, which is as follows:

[0104] Comparative Example 1

[0105] The device for preparing hydrogen peroxide by combining plasma with micro-droplets comprises:

[0106] The sheath air spray device 1 comprises an air inlet 11 , a water inlet 12 and a nozzle 13 .

[0107] The plasma reactor 2 is arranged below the sheath gas spray device 1, and the nozzle 13 extends into the cavity of the plasma reactor 2; the side wall of the plasma reactor 2 is provided with a condensed water inlet 21 and a condensed water outlet 22, and the side wall of the plasma reactor 2 is also provided with an exhaust port 23.

[0108] Two electrodes, including a first electrode 31 and a second electrode 32, are symmetrically arranged in the cavity of the plasma reactor 2. The interval between the first electrode 31 and the second electrode 32 is set to 1.5 mm, and the nozzle 13 is arranged above the interval at a distance of 3.5 mm.

[0109] Nitrogen is introduced through the air inlet 11, water is injected through the water inlet 12, and micro droplets are generated through the nozzle 13. When high voltage is applied to the two electrodes, the oxygen generated by the nozzle 13 flows through the electrodes to perform arc discharge, and the electrode arc discharge catalyzes the ejected droplets to obtain hydrogen peroxide.

[0110] The method for preparing hydrogen peroxide using the above plasma combined with micro-droplet hydrogen peroxide preparation device comprises the following steps:

[0111] A nitrogen gas with a flow rate of 5 L / min is passed through the air inlet 11, and a water with a flow rate of 25 mL / h is passed through the syringe pump 5 through the water inlet 12 into the sheath gas spray device 1. The sheath gas spray device 1 is passed through the pneumatic pressure method at 25° C. to provide shear force with the pressure of the external high-speed gas, so that the flowing liquid forms micro-droplets and compressed oxygen through the nozzle 13;

[0112] A pulse plasma generator 4 is used to apply a 2.5 kV voltage to the two electrodes, with a pulse width of 2.2 μs and a frequency of 20 kHz. The compressed oxygen flows through the gap between the first electrode 31 and the second electrode 32 to generate arc discharge, catalyze the micro-droplets, and synthesize hydrogen peroxide.

[0113] Comparative Example 2

[0114] The device for preparing hydrogen peroxide by combining plasma with micro-droplets comprises:

[0115] The sheath air spray device 1 comprises an air inlet 11 , a water inlet 12 and a nozzle 13 .

[0116] The plasma reactor 2 is arranged below the sheath gas spray device 1, and the nozzle 13 extends into the cavity of the plasma reactor 2; the side wall of the plasma reactor 2 is provided with a condensed water inlet 21 and a condensed water outlet 22, and the side wall of the plasma reactor 2 is also provided with an exhaust port 23.

[0117] Two electrodes, including a first electrode 31 and a second electrode 32, are symmetrically arranged in the cavity of the plasma reactor 2. The interval between the first electrode 31 and the second electrode 32 is set to 1.5 mm, and the nozzle 13 is arranged above the interval at a distance of 3.5 mm.

[0118] Air is introduced through the air inlet 11, water is injected through the water inlet 12, and micro droplets are generated through the nozzle 13. When high voltage is applied to the two electrodes, the oxygen generated by the nozzle 13 flows through the electrodes to perform arc discharge, and the electrode arc discharge catalyzes the ejected droplets to obtain hydrogen peroxide.

[0119] The method for preparing hydrogen peroxide using the above plasma combined with micro-droplet hydrogen peroxide preparation device comprises the following steps:

[0120] Air with a flow rate of 5 L / min is passed through the air inlet 11, and water with a flow rate of 25 mL / h is passed through the syringe pump 5 through the water inlet 12 into the sheath gas spray device 1. Through the sheath gas spray device 1, a pneumatic air pressure method is used at 25° C. to provide shear force with the pressure of external high-speed gas, so that the flowing liquid forms micro-droplets and compressed oxygen through the nozzle 13;

[0121] A pulse plasma generator 4 is used to apply a 2.5 kV voltage to the two electrodes, with a pulse width of 2.2 μs and a frequency of 20 kHz. The compressed oxygen flows through the gap between the first electrode 31 and the second electrode 32 to generate arc discharge, catalyze the micro-droplets, and synthesize hydrogen peroxide.

[0122] Comparative Example 3

[0123] Preparation of hydrogen peroxide using photocatalytic microdroplets (Ref:Energy Environ.Sci.,2023.16,1135DOI:10.1039 / d2ee03774b)

[0124] An inkjet printer was used to generate droplets with a diameter of 100 μm to 500 μm. The photoreaction was carried out under high humidity (about 90% relative humidity) and room temperature conditions, using 80 mM triethanolamine as an electron and proton donor, and the light source was a 365 nm ultraviolet lamp with a power density of 2.32 mW cm 2 , lighting time 3 hours.

[0125] Comparative Example 4

[0126] Preparation of hydrogen peroxide by microdroplet method (Ref:Chemical Science.https: / / doi.org / 10.1039 / d1sc06465g DOI:10.1039 / d1sc06465g)

[0127] Hydrogen peroxide is generated by a single microdroplet method. The spray device consists of concentric stainless steel tubes, where water is pushed through the inner tube and pressurized nitrogen flows through the outer ring to shear the liquid. The nitrogen flow rate is 5.3L / min and the liquid flow rate is 5-300μL / min. There is also a sealed glass housing connected to the spray device to collect the hydrogen peroxide sample and reduce sample loss.

[0128] Comparative Example 5

[0129] Preparation of hydrogen peroxide by plasma discharge combined with micro-droplets (Ref: IEEE transactions on industry applications, 2008, 44(2): 482-489.)

[0130] The reactor used in the experiment was configured with two stainless steel electrodes, with a pulse voltage of 25 kV applied at a frequency of 170 Hz and a power input of about 18 W. During the reaction, argon or oxygen was used as the carrier gas, with a gas flow rate of 20 L / min and a liquid flow rate of 10 mL / min.

[0131] Figure 2 to Figure 6 They are photos of sliding arc discharge with gas flow rates of 1 to 5 L / min. Figure 2 to Figure 6 It can be seen that the density and brightness of the plasma arc will be different. The higher the arc density and the brighter it is, the better the discharge effect will be. Figure 4 and Figure 5 The discharge effect is better, that is, the arc discharge effect of Example 1 and Example 2 is better.

[0132] Figure 7 The generation of microdroplets was demonstrated. Figure 8 It is the real-time voltage distribution monitored during the plasma discharge process, which conforms to the voltage distribution law of pulse discharge. Fig. 9 The comparison of plasma synthesis of hydrogen peroxide in different atmospheres confirms that the oxygen used in the present invention is the best gas component.

[0133] The concentrations of hydrogen peroxide prepared by the apparatus for preparing hydrogen peroxide by combining plasma with micro-droplets of Examples 1 to 5 of the present invention and Comparative Examples 1 to 2 and the method for preparing hydrogen peroxide of Comparative Examples 3 to 4 are shown in Table 1 below.

[0134] Table 1 Concentration of hydrogen peroxide prepared in Examples 1 to 5 of the present invention and Comparative Examples 1 to 5

[0135]

[0136]

[0137] As can be seen from Table 1, the concentration of hydrogen peroxide prepared by the device for preparing hydrogen peroxide by plasma combined with micro-droplets of the present invention is relatively high. In Comparative Example 1, oxygen is adjusted to nitrogen, and in Comparative Example 2, oxygen is adjusted to air. Comparative Examples 3 to 5 respectively prepare hydrogen peroxide by using photocatalytic micro-droplets, micro-droplet method and plasma discharge combined with micro-droplets in the prior art. The concentrations of hydrogen peroxide obtained by the above are not good. The present invention combines sheath gas spray and plasma sliding arc reactor to achieve the technical effect of preparing high-concentration hydrogen peroxide by plasma catalytic micro-droplets.

[0138] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A device for preparing hydrogen peroxide by combining plasma with micro-droplets, characterized in that: include: A sheath air spray device (1), wherein the sheath air spray device (1) comprises a nozzle (13); A plasma reactor (2) is arranged below the sheath gas spray device (1), and the nozzle (13) extends into the cavity of the plasma reactor (2); Two electrodes, including a first electrode (31) and a second electrode (32), are symmetrically arranged in the cavity of the plasma reactor (2), there is a gap between the first electrode (31) and the second electrode (32), and the nozzle (13) is located above the gap; Oxygen and water are introduced into the sheath gas spray device (1) to generate micro droplets through the nozzle (13). When high voltage is applied to two electrodes, the oxygen generated by the nozzle (13) flows through the electrodes to perform arc discharge, and the micro droplets ejected by the electrode arc discharge are catalyzed to obtain hydrogen peroxide.

2. The device for preparing hydrogen peroxide by plasma combined with micro-droplets according to claim 1, characterized in that: The size of the interval is 0.5 mm to 3 mm.

3. The device for preparing hydrogen peroxide by plasma combined with micro-droplets according to claim 1, characterized in that: The distance between the nozzle (13) and the interval is 1.5 mm to 5 mm.

4. The device for preparing hydrogen peroxide by plasma combined with micro-droplets according to claim 1, characterized in that: A condensed water inlet (21) and a condensed water outlet (22) are provided on the side wall of the plasma reactor (2).

5. The device for preparing hydrogen peroxide by plasma combined with micro-droplets according to claim 1, characterized in that: The side wall of the plasma reactor (2) is also provided with an exhaust port (23).

6. A method for preparing hydrogen peroxide using the plasma combined with micro-droplets hydrogen peroxide preparation device according to any one of claims 1 to 5, characterized in that: The following steps are involved: Passing oxygen and water into the sheath gas spray device (1), and being processed by the sheath gas spray device (1), obtaining micro droplets and compressed oxygen through the nozzle (13); A pulse plasma generator (4) is used to apply voltage to two electrodes, and the compressed oxygen flows through the gap between the first electrode (31) and the second electrode (32), generating arc discharge, catalyzing the micro droplets, and synthesizing hydrogen peroxide.

7. The method for preparing hydrogen peroxide according to claim 6, characterized in that: The voltage inputted by the plasma generator to the two electrodes is 1.5 kV to 4.5 kV, the pulse width is 1 μs to 5 μs, and the frequency is 10 kHz to 30 kHz.

8. The method for preparing hydrogen peroxide according to claim 6, characterized in that The oxygen flow rate is 1 L / min to 5 L / min.

9. The method for preparing hydrogen peroxide according to claim 6, characterized in that: The micro-droplets are formed by pneumatic air pressure method, using the pressure of external high-speed gas to provide shear force, so that flowing water forms micro-droplets, and the flow rate of the water is 20mL / h to 30mL / h.

10. The method for preparing hydrogen peroxide according to claim 6, characterized in that: The operating temperature of the sheath air spray device (1) is 10°C to 35°C.

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