CN201099636Y - A three-phase AC sliding arc unbalanced plasma sewage treatment device - Google Patents

Abstract

The utility model relates to a three-phase AC sliding arc unbalanced plasma sewage treatment device, which comprises a three-phase AC high-voltage power supply 1, a water-cooled glass reactor 3, three knife-shaped metal electrodes 5, an insulating cover 4, and an atomization Nozzle 6 etc. The three electrodes 5 are respectively connected to the three phase lines of the three-phase AC plasma power supply, the sewage provided by the sewage source 8 and the gas provided by the carrier gas source 9 pass through the atomizing nozzle 6 to form a gas-liquid mixture and spray it into the water-cooled glass reactor 3, The gas-liquid mixture drives the high-voltage breakdown arc with the minimum distance between the electrodes to quickly slide downstream along the electrode surface and form a pulsed sliding arc discharge10 on the electrode surface, thereby generating O, ^OH , H ₂ O ₂ , HO ₂ ^, H and other active particles, ultraviolet rays and other components of the sliding arc non-equilibrium plasma, the organic pollutants in the sewage are degraded into small molecular organics under the action of active particle oxidation, ultraviolet photolysis, etc., and even directly converted into carbon dioxide and water, etc. .

Description

A three-phase AC sliding arc unbalanced plasma sewage treatment device

technical field

The utility model relates to a three-phase AC sliding arc unbalanced plasma sewage treatment device, which belongs to the field of environmental technology and water treatment.

Background technique

Compared with the application of plasma technology in the field of waste gas treatment, non-equilibrium plasma (or non-thermal plasma) started late in water treatment. Due to its unique advantages and good pollutant removal efficiency, it has shown a good The application prospect has gradually become a research hotspot. Non-equilibrium plasma can be generated by glow discharge, corona discharge, pulse discharge, dielectric barrier discharge and non-thermal arc discharge. In 1902, AyrtonH. published the voltage-current characteristics of the free non-thermal arc of carbon electrodes in the atmosphere, and listed the reference range of this free non-thermal arc; The sliding arc discharge device for cooling the arc produces atmospheric pressure non-thermal arc plasma (French patent 2639172); later, foreign researchers in France, the United States, Russia, Poland and other countries also carried out research on sliding arc discharge, which not only includes sliding arc discharge plasma It is also applied in the fields of air pollutant control, synthesis gas production, organic solvent purification, etc., such as Fridman A., etc. analyzed the equilibrium state and non-equilibrium state in sliding arc discharge (Fridman A., et al.J.Prog.Energy and Comb.Sci.1999, 25:211-231.); Czernichowski A. etc. use hydrogen H ₂ as a reducing gas to catalytically decompose SO ₂ , and the research shows that 67% of SO ₂ is converted into elemental sulfur, using Research on the removal of volatile organic pollutants such as formaldehyde, toluene and heptane by sliding arc discharge plasma, the maximum removal rate of heptane can reach 100% (Czernichowski A., et al.Chemtech.1996, 26 (4): 45-49 .); Krawczyk K. etc. have reported utilizing sliding arc discharge to treat waste gas containing CCl ₄ , and the degradation rate of CCl ₄ reaches 100% (Krawczyk K., et al.Plasma Chem.Plasma Process.2003, 24 (2): 155 -167.); Moussa D. et al installed the two electrodes connected to the power supply directly above the organic solvent, injected the active particles generated by the single-phase AC sliding arc discharge into the liquid, and oxidized and decomposed the organic matter (Moussa D. , et al. J. Hazard. Mater. B. 2003, 102: 189-200.). In China, the research on sliding arc discharge is in its infancy, and there is some research on the physical characteristics of sliding arc discharge. For example, Lin Lie et al. have developed magnetically driven sliding arc discharge atmospheric pressure non-equilibrium plasma (Chinese patent 97111936.8), and the research mainly focuses on In terms of the physical characteristics of the sliding arc discharge driven by DC pure airflow; Xia Weidong et al. carried out a study on the discharge characteristics of the DC two-electrode magnetically driven sliding arc (Li Lei, Xia Weidong, et al. Nuclear Technology. 2004, 27(5): 350-353. ); but there is little research on the control of pollutants, mainly Du Changming and others carried out the research of single-phase AC sliding arc discharge, and applied it to the removal of polycyclic aromatic hydrocarbons and carbon black particles in exhaust gas (Du Changming, et al. China Chinese Journal of Electrical Engineering. 2006, 26(1): 77-81.), the research shows that the single-phase AC sliding arc discharge has the disadvantages of small discharge area and small processing capacity. So far, reviewing the domestic and foreign literature and materials, there is no research or report on the treatment of sewage by three-phase AC sliding arc non-equilibrium plasma.

Contents of the invention

The purpose of the utility model is to provide a three-phase AC sliding arc unbalanced plasma sewage treatment device with low cost, large discharge area and strong processing capacity.

The purpose of this utility model is achieved in that:

A three-phase AC sliding arc unbalanced plasma sewage treatment device, comprising: a three-phase AC high-voltage power supply 1, a plasma reactor main body, a spray system, and the like. The main body of the plasma reactor is composed of a water-cooled glass reactor 3, three knife-shaped metal electrodes 5 and an insulating cover 4. The electrodes are fixed in the insulating cover through insulating pillars 2, and the pre-installed metal conductors and power lines in the insulating pillars Connected; the spray system is composed of atomizing nozzle 6, water pump 7, sewage source 8 and carrier gas source 9.

The three-phase AC high-voltage power supply 1 is a transformer with boosting and current limiting functions, and the output voltage is controlled within the range of 5-10kV.

The three knife-shaped metal electrodes 5 are arranged with a difference of 120 degrees, and the minimum distance between two adjacent electrodes is in the range of 1-3mm; the materials for making the electrodes can be selected from tungsten, aluminum and stainless steel; the thickness of the electrodes is 1 -2mm, length 50-100mm, width 20-35mm, the specific size is determined according to the power of the unbalanced plasma generating device.

The water-cooled glass reactor 3 adopts a double sleeve form, including a drain port 11, a cooling water inlet 12, a cooling water outlet 13 and an exhaust port 14, and its specific size is determined according to the size of the electrode 5.

The insulating cover 4 and the insulating support 2 are made of insulating materials such as polytetrafluoroethylene rods or nylon rods, and their specific dimensions are determined according to the size of the electrodes 5 and the water-cooled glass reactor 3 .

The nozzle diameter of the atomizing nozzle 6 is 0.5-2mm.

The sewage source 8 may be waste water produced by chemical reaction, dyestuff, printing and dyeing, fermentation, pharmaceutical, papermaking and other industries, and the flow rate is controlled within the range of 1-6L/h.

The gas of the carrier gas source 9 is air or oxygen, and the flow rate is controlled within the range of 200-1000L/h.

Non-equilibrium plasma sewage treatment method is:

1) First turn on the cooling water device to provide cooling water;

2) Open the sewage source 8, use the water pump and flowmeter in the system to adjust and control the sewage flow, open the carrier gas source 9, use the flowmeter in the system to adjust and control the gas flow, the sewage and the carrier flow pass through the atomizing nozzle 6 to generate a gas-liquid mixture fluid ;

3) Turn on the power supply, adjust the output voltage of the high-voltage end of the three-phase AC high-voltage power supply 1, use the potential difference between the electrodes to form a breakdown discharge arc at the minimum distance between the electrodes, and the formation time between the three discharge arcs is in phase With a difference of 120 degrees, the three breakdown discharge arcs are driven by the gas-liquid flow, quickly slide downstream along the electrode surface, and extinguish after the arc reaches a certain length. At the same time, the arc is ignited at the minimum distance between the electrodes , and repeat the above process to form a pulsed sliding arc discharge 10, thereby generating a three-phase AC sliding arc non-equilibrium plasma containing active particles such as O, ^OH , H ₂ O ₂ , HO ₂ ^, and H, ultraviolet rays and other components , The organic pollutants in the sewage are degraded into small molecular organic matter under the action of active particle oxidation, ultraviolet photolysis, etc., and even directly converted into carbon dioxide and water.

The three-phase AC sliding arc unbalanced plasma sewage sewage treatment method and device described in the utility model have the following characteristics:

1) A large number of active particles ( ^OH , O, HO ₂ ^, H ₂ O ₂ and H ₃ O ⁺ , etc.) and ultraviolet rays are generated during gas-liquid sliding arc discharge.

High-energy particles bombard H ₂ O and O ₂ ^to generate OH and O:

H ₂ O+e ^- →H+ ^OH +e ^-

e ^- +H ₂ O→2e ^- +O+H ^· +H ⁺

O ₂ +e ^- →2O+e ^-

O ₂ +H ^· →HO ₂ ^·

^· OH can also be produced by the collision of H ₂ O and O:

H ₂ O+O→ ^OH + ^OH

H ₂ O+e ^- →H ₂ O ⁺ +2e ^-

H ₂ O ₂ production can be expressed as a whole as follows:

2H ₂ O→H ₂ O ₂ +H ₂

Water undergoes an ionization reaction to generate hydronium ions H ₃ O ⁺ :

H ₂ O+e ^- →H ₂ O ⁺ +2e ^-

H ₂ O ⁺ +H ₂ O→H ₃ O ⁺ +OH ^*

H ₃ O ⁺ then reacts very quickly with water to generate cluster ions:

H ₃ O ⁺ +2H ₂ O→H ₅ O ₂ ⁺ +H ₂ O

H ⁺ ·(n-1)H ₂ O+2H ₂ O→H ⁺ ·nH ₂ O+H ₂ O

When air is used as the carrier gas, the excited nitrogen will form NO ^Oxidizing particles:

N ₂ ^* +O ₂ →2NO ^·

2) The sewage is atomized into an aerosol form, which increases the concentration of pollutants on the surface of the droplets. Liquids with different surface tension constants are mixed, and those with small surface tension constants tend to concentrate to the surface; small diameter droplets strengthen this process, and pollution The substances are concentrated in the discharge area, increasing the probability of contacting active particles.

3) The electric field on the surface of the droplet is enhanced, and the water with a high dielectric constant (ε=81) increases the electric field intensity on the surface. Compared with a single medium, the avalanche of electrons and ions will occur on the surface of the droplet.

4) The increase of the water-air contact surface area improves the mass transfer factor of active particles and pollutants, and helps the degradation of pollutants in sewage.

The three-phase AC sliding arc unbalanced plasma device described in the utility model can be applied to sewage treatment in environmental engineering, such as degradation of organic waste water produced by chemical reactions, dyes, printing and dyeing, fermentation, pharmaceuticals and other industries, and can also be used for water body sterilization .

Description of drawings

Accompanying drawing is the structural representation of the utility model.

In the figure: 1 three-phase AC high-voltage power supply, 2 insulating pillars, 3 water-cooled glass reactor, 4 insulating cover, 5 electrodes, 6 atomizing nozzle, 7 water pump, 8 sewage source, 9 carrier gas source, 10 sliding arc discharge, 11 Outlet, 12 cooling water inlets, 13 cooling water outlets, 14 exhaust ports.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is described further.

Example 1

Referring to the accompanying drawings, the three electrodes 5 are respectively connected to the three phase lines of the three-phase AC plasma power supply, the sewage provided by the sewage source 8 and the gas provided by the carrier gas source 9 pass through the atomizing nozzle 6 to form a gas-liquid mixture and spray it into the water-cooled glass Reactor 3, the gas-liquid mixture flows to the drain end of water-cooled glass reactor 3 through the arcing end with the smallest distance between electrodes.

In this embodiment, the output voltage of the three-phase AC high-voltage power supply 1 is controlled at 5kV; the three electrodes are all made of metal material stainless steel, the minimum distance between two adjacent electrodes is 2mm, the electrode thickness is 2mm, the length is 100mm, and the width is 30mm; The water-cooled glass reactor 3 has a diameter of 100mm and a volume of 2L; the insulating support 2 and the insulating cover 4 are made of polytetrafluoroethylene rod insulating material, and the insulating cover 4 has a diameter of 100mm and a height of 50mm; the gas of the carrier gas source 9 is air, and the flow rate is controlled at 600L /h; Sewage source 8 is simulated wastewater of phenol and 4-chlorophenol, with a volume of 1L. The experimental conditions, test data and results are shown in Table 1.

Table 1

Pollutants Sewage flow (L/h) Initial concentration (mg/L) Processing time (min) Final Concentration (mg/L) Removal rate (%) Phenol 2 200 30 17 91.5 Phenol 2 400 30 79 80 4-Chlorophenol 2 200 30 25 87.5 4-Chlorophenol 2 400 30 75 81

Example 2

The device of this embodiment is the same as that of Embodiment 1, and the only difference is that the output voltage of the three-phase AC high-voltage power supply 1 is controlled at 10kV; the gas of the carrier gas source 9 is selected from air and oxygen respectively, and the flow rate is controlled at 800L/h; the sewage source 8 Azoic acid orange 7 was used to simulate printing and dyeing wastewater. The experimental conditions, test data and results are shown in Table 2.

Table 2

Pollutants Carrier gas type Sewage flow (L/h) Initial concentration (mg/L) Processing time (min) Final Concentration (mg/L) Removal rate (%) Acid Orange 7 Air 2.4 50 25 5 90 Acid Orange 7 Oxygen 2.4 50 25 1 98 Acid Orange 7 Air 2.4 100 25 twenty four 76 Acid Orange 7 Oxygen 2.4 100 25 15 85 Acid Orange 7 Air 2.4 200 25 56 72 Acid Orange 7 Oxygen 2.4 200 25 40 80

Claims (8)

1. three-phase alternating current gliding arc discharge plasma waste disposal plant, it is characterized in that comprising: three-phase alternating current high-voltage power supply (1), plasma reactor main body, fog system, the plasma reactor main body is made of water-cooled glass reaction still (3), 3 knife-edge metal electrodes (5) and insulating cover (4), electrode is fixed in the insulating cover by insulation column (2), and links to each other with supply lead by the preassembled metallic conductor in the insulation column; Fog system is made of atomizing nozzle (6), water pump (7), source of sewage (8) and carrier gas source (9).

2. three-phase alternating current gliding arc discharge plasma waste disposal plant according to claim 1, it is characterized in that: described three-phase alternating current high-voltage power supply (1), for having the transformer that boosts with current-limiting function, the voltage control of output is in the 5-10kV scope.

3. three-phase alternating current gliding arc discharge plasma waste disposal plant according to claim 1 is characterized in that: described 3 knife-edge metal electrodes (5) are arranged by differing 120 degree, and the minor increment between adjacent two electrodes is in the 1-3mm scope; Make the material of electrode and can select tungsten, aluminium and stainless steel for use; The thickness of electrode is 1-2mm, long 50-100mm, wide 20-35mm.

4. three-phase alternating current gliding arc discharge plasma waste disposal plant according to claim 1 and 2, it is characterized in that: described water-cooled glass reaction still (3) adopts two form of sleeve, comprises water port (11), cooling water inlet (12) cooling water outlet (13) and venting port (14).

5. according to claim 1,2 or 3 described three-phase alternating current gliding arc discharge plasma waste disposal plants, it is characterized in that: described insulating cover (4) and insulation column (2) adopt teflon rod or nylon rod insulating material to make.

6. three-phase alternating current gliding arc discharge plasma waste disposal plant according to claim 1 is characterized in that: the nozzle diameter of described atomizing nozzle (6) is 0.5-2mm.

7. three-phase alternating current gliding arc discharge plasma waste disposal plant according to claim 1, it is characterized in that: described source of sewage (8), can be the waste water of chemical reaction, dyestuff, printing and dyeing, fermentation, pharmacy, paper industry generation, flow control be in the 1-6L/h scope.

8. three-phase alternating current gliding arc discharge plasma waste disposal plant according to claim 1 is characterized in that: the gas of described carrier gas source (9) is air or oxygen, and flow control is in the 200-1000L/h scope.

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