CN103127810B - Non-homogeneous field intensity plasma emission-control equipment and treatment system - Google Patents

Abstract

A non-uniform field strength plasma waste gas treatment device and treatment system. The treatment system includes an intake pipe, a packing tower, a treatment device, a centrifugal fan, and an exhaust pipe connected in sequence. Several layers of plasma treatment mechanisms are installed in the plasma shell of the treatment device. The processing mechanism includes a base, an annular flange is arranged inside the base, and the ground electrode plate and the high-voltage electrode plate are connected to the front and back of the flange. There is an air outlet between the ground electrode plate and the flange, and an insulating medium plate between the two. There are several pointed cones on the front surface of the high-voltage electrode plate, and through holes are provided at the tips. The outer surface of the ground electrode plate and the rear surface of the high-voltage electrode plate are respectively provided with the first and second insulating layers, and the second insulating layer is provided with the second through hole. The ground electrode plate is respectively connected with the high voltage end and the ground end of the high voltage power supply through electrode lead wires. The invention can generate high-density plasma under a relatively low breakdown field strength, can process all gases, prolongs the interaction time between gas and plasma, and improves processing efficiency.

Description

Non-uniform field strength plasma waste gas treatment device and treatment system

technical field

The invention relates to a waste gas purification device, in particular to a non-uniform field strength plasma waste gas treatment device and a treatment system.

Background technique

With the development of the economy, gaseous pollution such as H _{2 S} , SO ₂ , NO _x , VOCs, etc. produced in the field of industrial production is becoming more and more serious. Relevant national laws and regulations and industry standards have strict restrictions on gas emission standards, and the control of polluted gases is the key to improving environmental quality.

The traditional methods of controlling polluted gases include combustion method, adsorption method, biological method, membrane separation method, photocatalytic method and so on. The disadvantage of the combustion method is that it consumes more auxiliary fuel, wastes heat energy, and causes secondary pollution during incomplete combustion; High consumption, complex process, continuous operation of the adsorption element, when there are colloidal substances or other impurities in the exhaust gas, the adsorbent is prone to failure, etc.; the essence of the biological method is to use the active microorganisms accumulated on the medium to use gas pollutants as its life activities The energy or nutrients are metabolized and degraded. The disadvantage is that microorganisms are sensitive to temperature and humidity changes.

Low-temperature plasma technology is a hot technology in the field of gaseous pollutant control in recent years. Compared with traditional air purification technology, low-temperature plasma technology has the characteristics of short treatment process, high efficiency, low energy consumption, less secondary pollution, and wide application range. Plasma is a mixed state of electrons, positive and negative ions, excited atoms, atoms, and free radicals. The state of plasma mainly depends on physical and chemical parameters such as its chemical composition, particle density and particle temperature, among which the density and temperature of particles are the two most basic parameters of plasma. In the plasma environment, various chemical reactions are carried out in a highly excited state, and the active particles produced by the usual chemical reactions are more diverse, more active, and more likely to react with pollutants in the exhaust gas. In a short period of time, the pollutant molecules are decomposed, so as to achieve the purpose of degrading pollutants. The common discharge forms of low temperature plasma technology are: arc, dielectric barrier discharge, glow discharge and corona discharge. The high temperature and electrode wear of the arc make it difficult to apply in polluted gases. It is very difficult to achieve a uniform and stable discharge in the form of glow under atmospheric pressure. The corona area of corona discharge is small and limited to the vicinity of the corona electrode, and the discharge current is relatively weak. Dielectric barrier discharge has the characteristics of high current density, high electron density and operation under normal pressure, so it has a good application prospect in the treatment of industrial polluted gases.

The conventional dielectric barrier discharge structure has a higher breakdown field strength and a smaller discharge area (such as the axial type) due to the presence of a dielectric. Due to the small discharge area, the reaction time between the gas and the plasma is short at the same flow rate, the polluted gas fails to fully react or some gas is discharged with the tail gas without plasma treatment, and the treatment efficiency is low.

Contents of the invention

The object of the present invention is to provide a non-uniform field strength plasma exhaust gas treatment device and treatment system, which can generate high-density plasma at a lower breakdown field strength, and all the treatment gas passes through the plasma region, while prolonging the pollution The interaction time between gas and plasma improves processing efficiency and reduces energy consumption.

In order to achieve the above object, the technical solution of the present invention is: a non-uniform field strength plasma exhaust gas treatment device, which includes a plasma shell, and the plasma shell is provided with an inlet and an outlet, located between the inlet and the outlet. Several plasma processing mechanisms are installed in at least one cross-section of the inner cavity of the plasma housing between them, and the plasma processing mechanisms located in the same cross-section are connected to each other along the outer edge direction and fill up the cross-section where they are located. The plasma processing mechanism is perpendicular to the air inlet of the plasma shell, and the plasma processing mechanism includes a frame-shaped base, the base is made of insulating material, and the inner cavity wall of the base is extended with a ring-shaped protrusion along the circumferential direction. The front and back of the flange are respectively connected to the ground electrode plate and the high-voltage electrode plate, and an air outlet is provided between the outer edge of the ground electrode plate and the flange, and an air outlet is provided between the flange and the ground electrode plate An insulating medium plate, the outer surface of the ground electrode plate is provided with a first insulating layer, the ground electrode lead-out line is connected to the ground electrode plate, and the ground electrode lead-out line passes through the first insulating layer and connects with the high-voltage AC power supply The ground terminal is connected, the front surface of the high-voltage electrode plate has several pointed cones, the rear surface of each of the pointed cones is a corresponding tapered groove, and the tip of each of the pointed cones is respectively provided with a first through hole , the rear surface of the high-voltage electrode plate is provided with a second insulating layer, and the positions corresponding to the front and rear positions of the first through holes on the second insulating layer are respectively provided with second through holes, and the high-voltage electrode plate is connected to The high-voltage electrode lead-out wire is connected to the high-voltage end of the high-voltage power supply after passing through the base.

The non-uniform field strength plasma waste gas treatment device of the present invention, wherein the plasma shell is a cuboid box structure, and the left and right ends are respectively provided with the gas inlet and outlet with variable diameters, and the plasma processing mechanism is basically The seat is a rectangular frame structure, and the bases of adjacent plasma processing mechanisms and between the adjacent bases and the plasma housing are connected together by C-shaped channel steel and fixing screws.

In the non-uniform field strength plasma exhaust gas treatment device of the present invention, an inspection door is provided on the plasma housing.

The exhaust gas treatment system of the non-uniform field strength plasma exhaust gas treatment device of the present invention includes at least one inlet pipe and one exhaust pipe, wherein each of the inlet pipes is respectively connected with the inlet of the packed tower, and the exhaust pipe of each of the packed towers is The gas ports communicate with the air inlets of the plasma housings of the processing device through the first connecting pipes respectively, and the gas outlets of the plasma housings respectively communicate with the centrifugal fans through the second connecting pipes, and the centrifugal fans respectively communicate with the centrifugal fans through the first connecting pipes. The three connecting pipes communicate with at least one exhaust pipe.

In the non-uniform field strength plasma exhaust gas treatment system of the present invention, at least one plasma housing equipped with a plasma processing mechanism is connected in series between the air inlet of each plasma housing and each second connecting pipe.

In the non-uniform field strength plasma waste gas treatment system of the present invention, the intake pipe is provided with an intake butterfly valve.

The non-uniform field strength plasma waste gas treatment system of the present invention, wherein the inlet pipe communicates with one end of the first bypass pipe, the first bypass pipe is provided with a bypass butterfly valve, and the other end of the first bypass pipe One end communicates with the second connecting pipe.

After adopting the above scheme, the non-uniform field strength plasma waste gas treatment device of the present invention is connected to the waste gas, and all the waste gas passes through the plasma treatment mechanisms in the inner cavity of the plasma shell, and is connected to the high-voltage AC power supply. The tip generates a strong electric field, so that the device can generate high-density plasma at a lower breakdown voltage. This structure overcomes the problem that the conventional dielectric barrier discharge structure has a high breakdown field strength due to the existence of the medium. Due to the sharp cone There is a vent at the tip of the body, which serves as a discharge electrode, and at the same time all polluted gases can pass through, which improves the gas treatment efficiency and reduces energy consumption. Due to the effect of high dielectric constant insulating medium, it is easy to form a stable discharge area. Plasma, to prolong the interaction time between plasma and polluted gas, when the waste gas passes through the plasma treatment mechanism, the lower energy electrons generated in the high-voltage discharge area collide with the particles and microorganisms in the waste gas to charge them, and then they are adsorbed and removed by the electrostatic field The high-energy electrons generated in the high-voltage discharge area directly collide with the chemical substances in the exhaust gas to ionize and decompose them; the high-energy electrons generated in the high-voltage discharge area interact with various components in the exhaust gas to generate free radicals and harmful substances Two-body or even three-body collisions with free radicals become harmless.

The further beneficial effects of the present invention are: the plasma housing is designed as a cuboid box structure, the base of the plasma processing mechanism is designed as a rectangular frame structure, between the bases of adjacent plasma processing mechanisms and adjacent bases and plasma The shells are connected together by C-shaped channel steel and fixing screws, so that the structure of the design is simple and easy to install.

A further beneficial effect of the present invention is that: the purpose of providing an inspection door on the plasma housing is to facilitate inspection and maintenance of the plasma processing mechanism in the inner chamber of the plasma housing.

The further beneficial effects of the present invention are: each intake pipe of the non-uniform field strength plasma waste gas treatment system of the present invention is connected to the waste gas, and after the waste gas is preliminarily purified by the packing tower, all of the waste gas passes through the plasma treatment mechanisms in the inner cavity of the plasma housing, and is connected A high-voltage AC power supply generates a strong electric field at the tip of each pointed cone of the high-voltage electrode plate, so that the device can generate high-density plasma at a lower breakdown voltage. This structure overcomes the conventional dielectric barrier discharge structure due to the presence of a medium The problem of high breakdown field strength, because the tip of the cone has a vent hole, it is used as a discharge electrode, and all polluted gases can pass through it, which improves the gas processing efficiency and reduces energy consumption. The role of the electric constant insulating medium is easy to form a stable plasma in the discharge area, prolonging the interaction time between the plasma and the polluted gas. When the exhaust gas passes through the plasma processing mechanism, the lower energy electrons generated in the high-voltage discharge area and the particles in the exhaust gas and Microorganisms collide to charge them, and then they are adsorbed and removed by the electrostatic field; electrons with higher energy generated in the high-voltage discharge area directly collide with chemical substances in the exhaust gas to ionize and decompose them; electrons with higher energy generated in the high-voltage discharge area and A variety of components in the exhaust gas interact to generate free radicals, and harmful substances and free radicals undergo two-body or even three-body collisions to become harmless substances.

The further beneficial effects of the present invention are: at least one plasma housing with a plasma processing mechanism inside is connected in series between the air inlets of each plasma housing and each second connecting pipe, the purpose of which is to further prolong the distance between the polluted gas and the Plasma action time, improve processing efficiency.

The further beneficial effect of the present invention is: the purpose of setting the intake butterfly valve on the intake pipe is to adjust the flow of exhaust gas and close the intake butterfly valve in case of emergency, so as to protect the safety of the system.

A further beneficial effect of the present invention is: the first bypass pipe is connected between the intake pipe and the second connecting pipe, so that when the system device fails, the exhaust gas can also be discharged through the first bypass pipe.

Description of drawings

Fig. 1 is a structural schematic diagram of Embodiment 1 of the non-uniform field strength plasma waste gas treatment system of the present invention;

Fig. 2 is a front sectional view of the plasma treatment mechanism of the non-uniform field intensity plasma waste gas treatment device of the present invention;

Fig. 3 is a top view of the plasma treatment mechanism of the non-uniform field strength plasma waste gas treatment device of the present invention;

Figure 4 is a front view of a single plasma processing mechanism of the present invention;

Figure 5 is a rear view of a single plasma processing mechanism of the present invention;

Figure 6 is a right side view of a single plasma processing mechanism of the present invention;

Fig. 7 is the A-A direction sectional view of Fig. 4;

Fig. 8 is the B-B direction sectional view of Fig. 5;

Fig. 9 is a schematic structural diagram of Embodiment 2 of the non-uniform field strength plasma waste gas treatment system of the present invention;

Fig. 10 is a schematic structural diagram of Embodiment 3 of the non-uniform field strength plasma waste gas treatment system of the present invention.

Below in conjunction with accompanying drawing, the present invention will be further described by embodiment;

detailed description

As shown in FIG. 1 , a schematic structural diagram of Embodiment 1 of the non-uniform field strength plasma waste gas treatment system of the present invention includes an inlet pipe 1 and an exhaust pipe 2 . An intake butterfly valve 22 is installed on the intake pipe 1 . The intake pipe 1 communicates with one end of a first bypass pipe 23 , and a bypass butterfly valve 24 is installed on the first bypass pipe 23 . The air inlet pipe 1 communicates with the air inlet of the packed tower 3 . The exhaust port of the packed tower 3 communicates with the air inlet of the plasma housing 5 through the first connecting pipe 4 . The plasma shell 5 is a cuboid box structure with a cavity, and its left and right ends are respectively provided with air inlets and outlets with variable diameters. The gas outlet of the plasma housing 5 communicates with the centrifugal fan 8 through the second connecting pipe 6 . The second connecting pipe 6 communicates with the other end of the first bypass pipe 23 . The centrifugal fan 8 communicates with the exhaust pipe 2 through the third connecting pipe 7 . The processing air volume of the centrifugal fan 8 is 2000m ³ /h. As shown in FIG. 2 and FIG. 3 , 4×5 plasma processing mechanisms 9 are installed in the same cross-section of the inner chamber of the plasma housing 5 . That is, four plasma processing mechanisms 9 are arranged horizontally, and five plasma processing mechanisms 9 are arranged vertically. Each adjacent plasma treatment unit 9 is connected to each other in the direction of the outer edge and fills up the cross section. The plasma treatment mechanism 9 is perpendicular to the air inlet of the plasma housing 5 . As shown in conjunction with FIGS. 4 to 8 , a single plasma processing mechanism 9 includes a base 10 , which is a rectangular frame structure. Its size is 30cm x 30cm. The base 10 is made of insulating material. Adjacent bases 10 , and adjacent bases 10 and plasma housing 5 are connected to each other through C-shaped channel steel 27 and fixing screws 28 . The inner wall of the base 10 has a square annular flange 11 extending in the circumferential direction. The front and rear of the flange 11 are respectively connected to the ground electrode plate 12 and the high voltage electrode plate 13 by fixing screws. The ground electrode plate 12 and the high voltage electrode plate 13 are made of corrosion-resistant metal plates. An air outlet 14 is provided between the outer edge of the ground electrode plate 12 and the flange 11 . An insulating medium plate 15 is provided between the flange 11 and the ground electrode plate 12 . The outer surface of the ground electrode plate 12 is provided with a first insulating layer 16 . The ground electrode plate 12 is connected to the ground electrode lead wire (not shown in the figure), and the ground electrode lead wire passes through the first insulating layer 16 and is connected to the ground terminal of the high-voltage AC power supply. 17 pointed cones. The height of the pointed cone 17 is 5 mm. The rear surface of each pointed cone 17 is a corresponding tapered groove. The tip of each pointed cone 17 is respectively processed with a first through hole 18 . The diameter of the first through hole 18 is 2 mm. The distance between two adjacent first through holes 18 is 10 mm. The distance between the high voltage electrode plate 13 and the ground electrode plate 12 is 8mm. The rear surface of the high voltage electrode plate 13 is provided with a second insulating layer 19 . Second through holes 20 are respectively processed on the second insulating layer 19 at positions corresponding to the front and rear of the first through holes 18 . The second through holes 20 are evenly distributed on the second insulating layer 19, so that the second insulating layer 19 forms a current equalizer. The high-voltage electrode plate 13 is connected to the high-voltage electrode lead wire 21 . The high-voltage electrode lead wire 21 passes through the base 10 and is connected to the high-voltage end of the high-voltage AC power supply.

During use, the exhaust gas is connected with the intake pipe 1, the centrifugal blower 8 is started, and the high-voltage power supply is connected. Under the action of the centrifugal fan 8, the styrene (C ₈ H ₈ ), carbon disulfide (CS ₂ ), hydrogen sulfide (H ₂ S) and methyl mercaptan (CH ₃ SH) in the exhaust gas are firstly distributed through the The packed tower 3 is purified and filtered, then enters the inner chamber of the plasma housing 5 and passes through 20 plasma processing mechanisms 9 evenly distributed in the same cross-section of the inner chamber of the plasma housing 5 . Switch on the high-voltage AC power supply, and generate a strong electric field at the tips of each pointed cone 17 of the high-voltage electrode plate 13, so that the system can generate high-density plasma at a lower breakdown voltage, because the pointed tip of the pointed cone 17 has a The first through hole 18 serves as a discharge electrode, and all polluted gases can pass through, which improves the gas processing efficiency and reduces energy consumption. The particles in the exhaust gas collide with the microorganisms to charge them, and then they are adsorbed and removed by the electrostatic field; the electrons with high energy generated in the high-voltage discharge area directly collide with the chemical substances in the exhaust gas to ionize and decompose them; the energy generated in the high-voltage discharge area Higher electrons interact with various components in the exhaust gas to generate free radicals, and harmful substances and free radicals undergo two-body or even three-body collisions to become harmless substances. The specific process is:

(1) In the plasma generation area, under the action of high-energy particles, strong oxidizing free radical O is generated; O ₂ +e→2O

(2) O interacts with organic molecules, small groups, and other free radicals, and the final products are CO, CO2, H ₂ O, etc. And styrene (C ₈ H ₈ ) is decomposed into carbon dioxide and water.

Finally, the treated gas is discharged through the exhaust pipe 2. After the system runs for 30 minutes each time, samples are taken at exhaust pipe 2.

The sampling and determination method of styrene (C ₈ H ₈ ) is in accordance with the national standard GB/T14677 gas chromatography;

The sampling and determination method of carbon disulfide (CS ₂ ) is in accordance with the national standard GB/T14680 diethylamine spectrophotometric method;

The sampling and determination methods of hydrogen sulfide (H ₂ S) and methyl mercaptan (CH ₃ SH) are in accordance with the national standard GB/T14678 gas chromatography;

Test results (according to GB1455493 emission standard for odor pollutants).

The implementation effect is shown in the table below

As shown in Figure 9, it is a schematic structural diagram of Embodiment 2 of the non-uniform field strength plasma waste gas treatment system of the present invention. Most of its structure is the same as that of Embodiment 1 above. The air pipe 1 and the two intake pipes 1 communicate with one end of a first bypass pipe 23 respectively, and bypass butterfly valves 24 are respectively installed on the two first bypass pipes 23 . The two inlet pipes 1 communicate with the inlets of the packed tower 3 respectively. The exhaust ports of the two packed towers 3 communicate with the air inlets of the plasma housing 5 through the first connecting pipe 4 respectively. The left and right ends of the two plasma shells 5 are respectively provided with an air inlet and an air outlet. The gas outlets of the two plasma shells 5 communicate with the two centrifugal fans 8 through the second connecting pipe 6 respectively. The two second connecting pipes 6 communicate with the other ends of the two first bypass pipes 23 respectively. Two centrifugal fans 8 communicate with the exhaust pipe 2 through two third connecting pipes 7 . This design can handle large flow of exhaust gas at the same time.

As shown in Figure 10, it is a schematic structural diagram of Embodiment 3 of the non-uniform field strength plasma waste gas treatment system of the present invention, most of its structure is the same as that of the above-mentioned Embodiment 1, and the difference is: in the plasma shell 5 A plasma housing 5 with 4×5 plasma processing mechanisms 9 inside is also connected in series between the gas outlet and the second connecting pipe 6 .

The above-mentioned embodiments are only descriptions of the preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Variations and improvements should fall within the scope of protection defined by the claims of the present invention.

Claims (7)

1. A non-uniform field strength plasma exhaust gas treatment device, characterized in that: comprising a plasma shell (5), said plasma shell (5) is provided with an air inlet and an air outlet, and is located between the air inlet and the air outlet Several plasma processing mechanisms (9) are installed in at least one cross-section of the inner cavity of the plasma shell (5), and the plasma processing mechanisms (9) located in the same cross-section are connected to each other along the outer edge direction and filled The cross section where the plasma processing mechanism (9) is perpendicular to the air inlet of the plasma housing (5), the plasma processing mechanism (9) includes a frame-shaped base (10), and the base (10) Made of insulating material, the inner cavity wall of the base (10) has an annular flange (11) extending in the circumferential direction, and the front and rear of the flange (11) are respectively connected to the ground electrode plate (12) and A high-voltage electrode plate (13), an air outlet (14) is provided between the outer edge of the ground electrode plate (12) and the flange (11), and an air outlet (14) is provided between the flange (11) and the ground electrode plate (12). An insulating medium plate (15) is provided, the outer surface of the ground electrode plate (12) is provided with a first insulating layer (16), the ground electrode lead wire is connected to the ground electrode plate (12), and the ground electrode The lead-out wire passes through the first insulating layer (16) and is connected to the ground terminal of the high-voltage AC power supply. The front surface of the high-voltage electrode plate (13) has several pointed cones (17), and each of the pointed cones (17 ) is a corresponding tapered groove, the tip of each of the pointed cones (17) is respectively provided with a first through hole (18), and the rear surface of the high voltage electrode plate (13) is provided with a second insulating layer (19), the second through holes (20) are respectively provided on the second insulating layer (19) corresponding to the front and rear positions of the first through holes (18), and the high voltage electrode plate (13) is connected to A high-voltage electrode lead-out wire (21). The high-voltage electrode lead-out wire (21) passes through the base (10) and is connected to the high-voltage end of the high-voltage power supply. 2. The non-uniform field strength plasma exhaust gas treatment device as claimed in claim 1, characterized in that: the plasma shell (5) is a cuboid box-type structure, and its left and right ends are respectively provided with variable-diameter Said inlet and outlet, the base (10) of the plasma processing mechanism (9) is a rectangular frame structure, between the bases (10) of the adjacent plasma processing mechanism (9) and adjacent bases (10) It is connected with the plasma shell (5) by C-shaped channel steel (27) and fixing screws (28) respectively. 3. The non-uniform field strength plasma waste gas treatment device according to claim 2, characterized in that: the plasma shell (5) is provided with an inspection door (26). 4. An exhaust gas treatment system using the non-uniform field strength plasma exhaust gas treatment device according to any one of claims 1-3, comprising at least one intake pipe (1) and an exhaust pipe (2), characterized in that : each of the air inlet pipes (1) is communicated with the air inlet of the packed tower (3) respectively, and the exhaust port of each of the packed towers (3) is connected to the plasma of the processing device through the first connecting pipe (4) respectively. The air inlets of the shells (5) are communicated, and the air outlets of each of the plasma shells (5) are respectively communicated with the centrifugal fans (8) through the second connecting pipes (6), and the centrifugal fans (8) are respectively connected through the second connecting pipes (6). The three connecting pipes (7) communicate with at least one exhaust pipe (2). 5. The exhaust gas treatment system according to claim 4, characterized in that: at least one plasma tube is connected in series between the air inlet of each plasma shell (5) and each second connecting pipe (6). Plasma housing (5) of processing mechanism (9). 6. The exhaust gas treatment system according to claim 5, characterized in that: the intake pipe (1) is provided with an intake butterfly valve (22). 7. The exhaust gas treatment system according to claim 6, characterized in that: the intake pipe (1) communicates with one end of the first bypass pipe (23), and the first bypass pipe (23) is provided with A bypass butterfly valve (24), the other end of the first bypass pipe (23) communicates with the second connecting pipe (6).