CN1261367C - Slide arc discharging plasma device for organic waste water treatment - Google Patents

Abstract

The invention discloses a sliding arc discharge plasma organic wastewater treatment device. A knife-shaped bifurcated electrode connected to a high-voltage power supply is installed on the insulating base of the reaction cover. The middle part of the insulating base has a waste liquid collection tank connected to the waste water tank. The notch is equipped with an atomizing nozzle, and the upper part of the reaction cover is equipped with a gas sampling port. 1. Exhaust pipe, the exhaust pipe is equipped with a cooling water jacket, the compressed air and the waste water tank are respectively connected to the atomizing nozzle through the conduit. Waste water and compressed air pass through the air atomization nozzle to form waste water mist to be treated, and the gas-water mixture pushes the sliding arc formed at the arc starting end to move downstream to generate a gas-liquid mixture sliding arc discharge, resulting in ozone, ultraviolet rays, high-energy electrons, and electrolysis. Active particles such as , OH and O directly act on the treated wastewater to realize online discharge treatment. The invention is especially used for the treatment of refractory high-concentration organic wastewater, and the removal rate of COD, BOD, etc. after treatment can reach more than 99% no matter how high the organic wastewater concentration is.

Description

Sliding arc discharge plasma organic wastewater treatment device

Technical field

The invention relates to a waste water treatment device, in particular to a sliding arc discharge plasma organic waste water treatment device.

Background technique

The treatment of organic wastewater, especially the treatment of high-concentration organic wastewater, is still a thorny problem, which plagues the chemical and pharmaceutical industries. There are many wastewater treatment methods in the prior art, and conventionally recommended biochemical methods, electrolysis methods and flocculation methods, etc. It is difficult to solve the problem of wastewater treatment containing complex organic matter, which is also an urgent problem to be solved in environmental protection. The research on the treatment of industrial wastewater by low-temperature plasma chemical method is not long in the world, and the methods that have been proposed include high-energy electron beam method and pulse discharge treatment method in water. Because the density of water is much greater than that of gas, when electrons shoot towards water, high-energy electrons lose kinetic energy quickly in frequent collisions with water molecules, and their penetration depth is very small, so it is difficult to handle large flow of water. The underwater pulse discharge method uses pulse arc discharge in water to treat water. The contact between the discharge part and the water is only limited to a discharge channel between the two electrodes. Molecules of harmful substances are only limited to the part in contact with the discharge channel. Therefore, both methods are difficult to achieve large-scale processing.

Sliding arc discharge plasma is a new technology that has just emerged in recent years and has been applied in environmental protection technology. This method can generate non-equilibrium plasma at atmospheric pressure or higher pressure. In recent years, sliding arc discharge has been used abroad. There are research reports on the treatment of H ₂ S, SO ₂ , N ₂ O and other waste gases by discharge technology, but there is no research or report on the treatment of waste water by sliding arc discharge at home and abroad.

Contents of the invention

The object of the present invention is to provide a sliding arc discharge plasma organic wastewater treatment device, which is suitable for treating refractory high-concentration organic wastewater by using sliding arc discharge plasma.

In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is that it includes: the bottom of the reaction cover is sequentially equipped with insulating bases from bottom to top, and the symmetrical insulating pillars on both sides of the insulating base are respectively equipped with lower, upper, and high-voltage power supplies. The connected knife-shaped bifurcated electrodes form an arc starting end. There is a waste liquid collection tank connected to the waste water tank in the middle of the insulating base. The notch of the waste liquid collection tank is equipped with a nozzle fixed on the insulating base. The gas sampling port, the exhaust pipe, and the cooling water jacket connected with the liquid collection bottle by a catheter are installed outside the exhaust pipe, and the compressed air of the air compressor and the waste water of the waste water tank are respectively connected to the nozzle through the pipe.

Compared with the background technology, the present invention has beneficial effects as follows: the plasma wastewater treatment of the present invention is mainly compared with the biochemical method in the wastewater treatment industry at present, and the plasma wastewater processor has higher advantages, (1) it can be processed continuously Wastewater does not require a long residence time, and the removal of organic pollutants is non-selective; (2) The raw materials for manufacturing electrodes are cheap, the system occupies a small area, and the operation and maintenance are convenient, and automatic control can be easily realized to ensure the treatment accuracy. Quality; (3) No need to add consumables such as medicines, only electricity, convenient and easy to get.

The present invention can adopt intermittent type and continuous type, such as manufacturing single equipment, used for factories with small wastewater output, etc., continuous type can be widely used in factories with large wastewater output. It is mainly used for high-concentration organic wastewater that is difficult to degrade, such as wastewater produced by chemical reactions, dyes, printing and dyeing, fermentation, pharmaceuticals, papermaking and other industries. No matter how high the concentration of organic wastewater is, the removal rate of COD and BOD after treatment can reach more than 99%.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Accompanying drawing is the structural representation of the present invention.

In the figure: 1 air compressor, 2 high-voltage insulated wire, 3 insulating base, 4 insulating pillar, 5 knife-shaped bifurcated electrode, 6 reaction cover, 7 waste water tank, 8 high-voltage power supply, 9 waste liquid collection tank, 10 nozzle, 11 Arc starting end, 12 sliding arc, 13 liquid storage tank, 14 catheter, 15 gas sampling port, 16 exhaust pipe, 17 cooling water jacket, 18 tail gas.

Detailed ways

As shown in the accompanying drawings, the present invention includes: an insulating base 3 is sequentially installed on the bottom of the reaction cover 6 from bottom to top, and the insulating supports 4 symmetrical on both sides of the insulating base 3 are respectively equipped with a large bottom and a small top, and a high-voltage power supply 8 The connected knife-shaped bifurcated electrodes 5 form an arcing end 11. The middle part of the insulating base 3 has a waste liquid collection tank 9 connected to the waste water tank 7. The slot of the waste liquid collection tank 9 is equipped with a nozzle 10 fixed on the insulating base 3. , the top of the reaction cover 6 is equipped with a gas sampling port 15 and an exhaust pipe 16 in turn, and the exhaust pipe 16 is equipped with a cooling water jacket 17 connected to the liquid collection bottle 13 with a catheter 14, the compressed air of the air compressor 1 and the waste gas. The waste water in the water tank 7 is connected to the nozzle 10 through the conduit respectively.

Said nozzle 10 has an orifice diameter of 1 to 5mm, and the model can adopt SUJ11, SUJ12 and the like.

The minimum distance between the two electrodes 5 of the knife-shaped fork at the arc starting end 11 is 2-5 mm.

The insulating base 3 is made of polytetrafluoroethylene, which acts as a fixed support; the insulating pillar 4, made of polytetrafluoroethylene, supports the electrodes; the knife-shaped bifurcated electrode 5 is made of aluminum alloy; the reaction cover 6 , made of tin; catheter tube 14, made of tin; exhaust pipe 16, made of tin;

The plasma wastewater treatment method is to connect the 10KV AC high-voltage power supply 8, the wastewater solution is sucked out from the water storage tank 7 through gas injection, and the compressed air of the air compressor 1 and the wastewater from the wastewater tank 7 are sprayed out of the gas-water mixture through the air atomizing nozzle 10 The velocity is greater than 10m/s, producing waste water atomized particles less than 15 microns, and the waste water mist pushes the sliding arc 12 formed by the arc starting end 11 to move downstream to generate sliding arc discharge, and non-equilibrium plasma is obtained under normal pressure to generate ozone Active particles such as , ultraviolet rays, high-energy electrons, electrolysis, OH and O directly act on the treated wastewater to realize online discharge treatment and turn the wastewater into harmless substances. The processing time is mainly determined by the time the water mist stays in the sliding arc discharge area, and the flow rate of the water mist is regulated by the nozzle 10 . Sampling is carried out through the gas sampling port 15 , the exhaust gas 18 is discharged through the exhaust pipe 16 , and under the cooling of the cooling water jacket 17 , the water vapor is condensed into liquid, and flows into the liquid storage tank 13 through the catheter 14 .

The wastewater treatment method and device of the present invention can play the following roles:

In the sliding arc discharge plasma, each sliding arc is a plasma channel, and a large number of high-energy electrons, ions, free radicals and other particles will be generated under high temperature and high pressure in the plasma channel, as shown in the following reaction formulas:

High-energy electrons and active free radicals (O, OH, e _oq ^- , HO ₂ ^-, etc.) will bombard and oxidize organic molecules, making them eventually degrade into harmless substances such as CO ₂ and H ₂ O. At the same time, due to the generation of high-temperature and high-pressure plasma channels, accompanied by strong ultraviolet light (wavelength 75-185nm) and huge shock waves (3-10Gpa), the following problems are caused in the solution of the plasma channel area and its outer area A physical and chemical reaction process: ozone oxidation, ultraviolet photolysis, liquid electrocavitation degradation and supercritical water oxidation degradation. U.S. California Institute of Technology Wilber and others used hydroelectric pulse plasma to perform degradation experiments on organic substances such as chlorophenol and TNT. After 1 minute, about 200 high-energy discharges (each discharge consumes 4-7KJ energy), the removal rate of these organic substances reaches 99%.

When the plasma channel is formed, due to its high temperature, it is like a light source that radiates strong ultraviolet light, and the radiated ultraviolet light is immediately absorbed by the atomized droplets around the plasma channel, which promotes the generation of dissolved oxygen in the water. Excited oxygen atoms interact with organic molecules to achieve the purpose of oxidizing organic matter.

Due to the huge shock pressure wave caused by the rapid outward expansion of the plasma channel, with the help of the hydroelectric cavitation (bubble) effect, it directly acts on the organic molecules to undergo pyrolysis and free radical degradation reactions.

Due to the heat transfer from the plasma channel to the surrounding atomized liquid droplets, many vapor bubbles are generated. Inside these bubbles, the temperature and pressure are high enough to form transient supercritical water. Therefore, the organic matter and oxygen in the bubbles are completely miscible with the supercritical water, so that the organic matter starts to oxidize spontaneously.

To sum up, the process of degrading organic matter by sliding arc discharge plasma is quite complicated, and it is a process of multiple oxidations alternating with each other.

The processing example of the present invention is as follows, the processing condition of method is: 7000～10000 volts voltage, frequency 50Hz, knife-shaped forked electrode length 160mm, wide 35mm, thick 2.5mm, nozzle orifice diameter 1mm, air pressure 0.3～1.5MP in the nozzle , the experimental supplies were collected from a pharmaceutical factory's pharmaceutical wastewater and concentrated waste liquid from the production of DSD acid.

Experiment 1#

Experimental supplies: pharmaceutical wastewater

Experimental conditions: voltage 1OkV, waste liquid flow rate 42.4ml/min, gas flow rate 11.2l/min, carrier gas air.

Pharmaceutical wastewater (unit: mg/l) Test items This technology is not used Adopt this technology CODCr 1570 17 BOD5 1340 19 NH3-N 1200 13

Experiment 2#

Experimental supplies: Concentrated waste liquid from the production of DSD acid

Experimental conditions: voltage 10kV, waste liquid flow rate 40.9ml/min, gas flow rate 10.71/min, carrier gas air.

Pharmaceutical wastewater (unit: mg/l) Test items This technology is not used Adopt this technology CODCr 1.46×105 97 BOD5 4660 37 NH3-N 8040 29

Measurement methods

BOD5: Dilution and inoculation method GB7488-87

CODCr: potassium dichromate method GB11914-89;

NH3-N: Nessler's reagent colorimetric method GB7479-87;

The experimental results show that the removal effect of organic wastewater is very good after being treated by this process.

Claims (3)

1. A sliding arc discharge plasma organic wastewater treatment device, characterized in that it comprises: an insulating base (3) is sequentially installed at the bottom of the reaction cover (6) from bottom to top, and insulating supports symmetrical on both sides of the insulating base (3) (4) are respectively equipped with knife-shaped bifurcated electrodes (5) connected to the high-voltage power supply (8) and form an arcing end (11), and the middle part of the insulating base (3) has a waste water tank (7) ) connected to the waste liquid collection tank (9), the nozzle (10) fixed on the insulating base (3) is installed in the notch of the waste liquid collection tank (9), and the gas sampling port ( 15), the exhaust pipe (16), the cooling water jacket (17) that the outlet pipe (16) is equipped with a useful guide tube (14) to link to the liquid storage tank (13), the compressed air of the air compressor (1) and The waste water in the waste water tank (7) is respectively connected to the nozzle (10) together through the conduit. 2. A sliding arc discharge plasma organic wastewater treatment device according to claim 1, characterized in that the diameter of the nozzle (10) is 1-5mm. 3. A sliding arc discharge plasma organic wastewater treatment device according to claim 1, characterized in that the distance between the two electrodes (5) of the knife-shaped bifurcation at the arc starting end (11) is the smallest It is 2-5mm.

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