CN201108798Y - A device for removing volatile organic pollutants - Google Patents

Abstract

A device for removing volatile organic pollutants belongs to the technical field of gas pollutant treatment. The device includes a gas inlet (1), a reactor (2), a power supply (3), and a gas outlet (4). It is characterized in that it also includes insulating sheets (5) at both ends of the reactor (2), and an inner Electrode (6), the outer electrode (7) wrapped around the outer tube of the reactor, the filler (8) in the reactor, the filler is a Raschig ring coated with a ferroelectric material, and the holes on both sides of the Raschig ring The inlet and outlet towards the reactor are evenly placed in the reactor. When the electric field intensity reaches a certain value, the filler will spontaneously polarize. The utility model can reduce the energy consumption of the reactor under the premise of maintaining the pollutant removal rate, and has a simple structure and strong applicability.

Description

A device for removing volatile organic pollutants

technical field

The utility model belongs to the technical field of gas pollutant treatment.

Background technique

Volatile organic compounds (VOCs) are a general term for a class of organic compounds, which have a high evaporation rate and are volatile at room temperature. It refers to organic matter with a saturated vapor pressure exceeding 70.91Pa or a boiling point less than 260°C at room temperature. It is the most common pollutant emitted by industries such as petroleum, chemical, pharmaceutical, printing, building materials, and spraying. The hazards of VOCs mainly include the following aspects: (1) Most VOCs are odorous and toxic. Many substances in VOCs are carcinogenic, teratogenic, and mutagenic. (2) Under the irradiation of light, many VOCs can easily undergo photochemical reactions with some oxidants to generate photochemical smog, which is harmful to human health and affects the growth of crops; (3) ) Some halogenated hydrocarbons may cause damage to the ozone layer, such as chlorofluorocarbons (CFCs) and chlorofluorocarbons; (4) Many VOCs are flammable and explosive compounds, which cause great hidden dangers to the production of enterprises.

Traditional VOCs treatment methods include: combustion method, absorption method, condensation method, adsorption method, etc. These methods have certain defects in technology and economy: either the initial investment and operating costs are high, or the treatment effect is not ideal, or secondary pollution is caused by improper follow-up treatment. Especially low-concentration, high-volume waste gas has not yet found a cost-effective treatment method. Among the many new technologies for environmental pollution control, low-temperature plasma technology is an environmentally friendly new technology with high efficiency, low energy consumption, wide application range, large processing capacity, and simple operation to treat toxic and refractory substances. It has been studied in recent years. hot spot. Patent 200410014135.X discloses a low-temperature plasma technology for treating volatile organic compounds. The removal of pollutants is achieved through high-voltage discharge, but it needs to consume a certain amount of energy. The structure diagram is shown in Figure 1. Patent 200410014131.1 discloses a low-temperature plasma technology for treating microbial pollutants, which also uses high-voltage discharge to remove microbial pollutants. Patent 200410014133.0 discloses a low-temperature plasma treatment method for H ₂ S and C ₂ S in industrial waste gas. Under the action of a pulse power supply, a low-temperature plasma field is formed in a plasma reactor to convert H ₂ S and C ₂ S into free Odor and low toxicity SO ₂ . The above-mentioned patents all realize the removal of pollutants under the action of high-voltage power supply, and consume a certain amount of energy in the actual operation process.

Utility model content

The purpose of the utility model is to provide a novel, high-efficiency, low-energy-consumption low-temperature plasma VOCs treatment device.

The utility model is a reactor that combines corona discharge and dielectric barrier discharge to generate plasma to degrade organic waste gas. Ferroelectric materials are added in the reactor, and the characteristics of spontaneous polarization of these materials under high electric field strength are used to effectively reduce the applied energy on the basis of ensuring the removal efficiency of pollutants or effectively improve the pollution under certain energy conditions. removal rate. When an external power supply is applied to the dielectric layer, the dielectric filler will be polarized, and a strong electric field will be formed near each filler, thereby generating a partial discharge. When the applied AC voltage exceeds the initial voltage generated by the corona, The reactor will be filled with a large number of high-energy electrons, which collide with pollutant molecules, thereby improving the efficiency of pollutant treatment. The influence of the electric field on the dielectric constant of different media is different. For linear dielectric materials, the polarization strength is directly proportional to the electric field strength, while the dielectric constant has little relationship with the electric field strength. For nonlinear materials, the polarization intensity has a nonlinear relationship with the electric field intensity, and the dielectric constant of the material also has a nonlinear relationship with the electric field intensity. The ferroelectric material selected in the utility model belongs to the nonlinear material. Accompanying drawing 2 is the relational curve of the dielectric constant of ferroelectric body and electric field strength, as can be seen from the figure, the relation of the dielectric constant of ferroelectric material and electric field strength is nonlinear relation, under certain electric field strength, The dielectric constant of the ferroelectric material will change sharply, so that the electric field of the reactor will increase sharply, so the degradation of VOCs can be effectively realized.

The structure of the reactor device is shown in Figure 3, including a gas inlet 1, a reactor 2, a power supply 3, and a gas outlet 4. It is characterized in that it also includes insulating sheets 5 at both ends of the reactor, an inner electrode 6 at the center of the reactor, and a reactor The outer electrode 7 wrapped around the outer tube and the filler 8 in the reactor are Raschig rings coated with ferroelectric materials, and the holes on both sides of the Raschig rings are evenly placed in the reactor toward the inlet and outlet of the reactor.

The ferroelectric materials selected by the reactor in the utility model include order-disorder ferroelectric sodium nitrite material and displacement ferroelectric barium titanate material. These materials are powdery substances. In the utility model, ceramic Raschig rings are selected as the matrix material, and ferroelectric powdery materials are coated on the surface of the ceramic Raschig rings. These ceramic Raschig rings are evenly placed in the reactor. On the one hand, they can The space of the reactor is effectively used. On the other hand, the holes on both sides of the Raschig ring face the inlet and outlet of the reactor, which can reduce the resistance of the airflow to reduce the pressure drop of the reactor.

Compared with the existing device, the volatile organic pollutant removal device provided by the utility model is different in that: a ferroelectric filler is added in the reactor, and when the electric field intensity reaches a certain value, the filler spontaneously polarizes, which can Make the reactor reduce energy consumption under the premise of maintaining the pollutant removal rate. At the same time, the sodium nitrite filler selected is easy for industrial application because of its low cost. The reactor can effectively reduce the unit energy consumption of the reactor for treating pollutants, and has a simple structure and strong applicability.

Description of drawings

Fig. 1 is a structural diagram of a VOCs treatment device disclosed in patent 200410014135.X, in which there are gas inlet 1, reactor 2, power supply 3, and gas outlet 4.

Fig. 2 is the relationship curve between the dielectric constant of the ferroelectric material and the effective field strength.

Fig. 3 is the structural diagram of the VOCs processing device provided by the utility model, wherein there are gas inlet 1, reactor 2, power supply 3, gas outlet 4, insulating sheet 5 at both ends of the reactor, inner electrode 6 at the center of the reactor, and the outer electrode of the reactor. The external electrode 7 wrapped in the tube, the filler 8 in the reactor.

Fig. 4 is an effect diagram of the VOCs treatment device provided by the utility model for the removal rate of toluene.

Detailed ways

The material of the reactor is a quartz glass tube with a wall thickness of 2.4 mm, an inner diameter of 17.9 mm and an outer diameter of 20.3 mm. Both ends of the reactor are sealed with polytetrafluoroethylene insulating sheets, and a round hole of φ = 4mm is opened at each end as the inlet and outlet of the processing gas. The inner electrode in the center of the reactor is made of φ = 1.62 mm tungsten wire, the outer wall of the quartz glass tube is wrapped with an iron mesh as the external electrode and grounded. The size of the Raschig ring filler in the reactor is 5.6 mm in inner diameter, 9.2 mm in outer diameter, and 10.5 mm in length, and ferroelectric material is coated on the Raschig ring substrate with a coating thickness of 0.5 mm. A high-voltage power supply is connected between the internal and external electrodes to provide energy for the reactor. During the discharge process, a large number of high-energy electrons and active groups are generated in the reactor and on the surface of the filler. Volatile organic gases enter the reactor from inlet 1. A series of physical and chemical reactions take place with active groups and high-energy electrons in the container, so that the pollutant molecules finally form non-toxic and harmless gas molecules, which are finally discharged from the gas outlet 4. Figure 3 shows the results of experiments with toluene, a representative of volatile organic compounds, as the target pollutant. The experimental conditions are that the applied voltage of the power supply is 10kV, and the flow rate of toluene at the inlet is about 2400mg/m ³ , which reflects the addition of toluene under different power frequency conditions. Barium titanate filler, sodium nitrite filler and toluene removal efficiency without filler, when the power frequency is 35KHz, the reactor without filler, the reactor with sodium nitrite filler and the reaction with barium titanate filler The toluene removal rates of the reactors were 68.7%, 76.8% and 89.6%, respectively, and the removal rates of the reactors with barium titanate and sodium nitrite fillers were higher than those of the reactors without fillers. In other words, while maintaining the toluene removal rate Under the premise of , the reactor with packing needs less energy than the unpacked reactor.

Claims (1)

1. A volatile organic pollutant removal device, comprising a gas inlet (1), a reactor (2), a power supply (3), and a gas outlet (4), characterized in that it also includes insulation at both ends of the reactor (2) sheet (5), the inner electrode (6) in the center of the reactor, the outer electrode (7) wrapped around the outer tube of the reactor, and the filler (8) in the reactor, the filler is a pulley coated with a ferroelectric material West ring, the holes on both sides of the Raschig ring are evenly placed in the reactor toward the inlet and outlet of the reactor.

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