CN202237791U - Organic gas plasma catalytic converter - Google Patents

Abstract

The utility model relates to an organic gas plasma catalytic converter, it includes a shell, parallelly connected or a plurality of electric fields of establishing ties in the shell, the electric field comprises negative electrode and positive electrode, all coats high dielectric constant material layer and electricity respectively connect to a high-voltage pulse power just, negative pole on just, the negative electrode, place the electric field catalyst honeycomb carrier that several porous ceramics made in the electric field, the difference packing load is TiO catalyst honeycomb carrier in₂And AL₂O₃A first catalyst of (2), supported by V₂O₅And TiO₂The second catalyst is connected with a section of non-electric field catalyst honeycomb carrier in series close to the electric field after the electric field, and the filling load is MnO₂The third catalyst of (1). The utility model discloses can improve energy utilization efficiency and reduce the CO emission by a wide margin.

Description

An organic gas plasma catalyst

technical field

The utility model relates to a reaction device for catalyzing and degrading organic gas in a plasma environment at normal temperature. the

Background technique

At present, the purification methods of organic gases in the field of environmental protection are divided into separation methods and degradation methods. Separation methods include solvent absorption, adsorption-desorption separation, condensation, and membrane separation, and degradation methods include combustion, catalytic combustion, biodegradation, and plasma elimination. the

The current plasma reactor structure is as shown in Figure 1: the first electrode 92 and the second electrode 93 electrically connected to the shell 91 in the shell 91 are powered by a direct current high voltage power supply 90, and the second electrode 93 passes through the discharge electrode 94 of the spike. A discharge is made to the first electrode 92 to generate plasma in the space of the housing 91 . The gas flow containing organic gas flows along the direction shown by C in the figure. In the plasma, the organic gas is partially decomposed to produce CO ₂ , H ₂ O, CO, and its intermediate product C _x H _y O _z . This structure not only The degradation rate is low, and the energy utilization rate is low, and the most important thing is to produce considerable CO, which brings more serious pollution.

Contents of the invention

The technical problem to be solved by the utility model is to improve the energy utilization efficiency of the gas plasma catalytic converter. the

Another technical problem to be solved by the utility model is to reduce the amount of CO produced. the

In order to solve the above-mentioned technical problems, the present invention provides an organic gas plasma catalytic converter, which includes a casing, in which a plurality of electric fields are connected in parallel or in series, and the electric field is composed of a casing as a negative electrode and a positive electrode, and the positive and negative electrodes are coated with The high dielectric constant material layer is electrically connected to the positive and negative poles of a high-voltage pulse power supply, and an electric field catalyst honeycomb carrier made of several porous ceramics is placed in the electric field, and the catalyst honeycomb carrier is filled with the first catalyst and the second catalyst respectively. , a section of non-electric field catalyst honeycomb carrier is connected in series next to the electric field, and filled with the third catalyst. the

The beneficial effect brought by the utility model is that because the high-voltage pulse power supply is used instead of the DC high-voltage power supply, most of the electric energy is used to generate high-energy electrons instead of heating gas, so the catalytic efficiency and energy utilization rate are greatly improved. . In addition, the third catalyst behind the electric field can completely oxidize CO into CO ₂ , so the amount of CO produced by the plasma catalyst can be greatly reduced.

Description of drawings

Figure 1 is a schematic diagram of the structure of the current plasma reactor. the

Fig. 2 is a schematic diagram of energy bands of a catalyst of the present invention. the

Fig. 3 is a schematic diagram of the reaction mechanism of the utility model. the

Fig. 4 is a schematic sectional view of the utility model. the

Fig. 5 is a schematic cross-sectional view of the A-A direction in Fig. 4 of the present invention. the

Detailed ways

As shown in Figures 4 and 5, the organic gas plasma catalytic converter of the present utility model comprises a shell 10, and a plurality of electric fields 20 are connected in parallel or in series in the shell 10, and the electric field 20 is made up of shell 10 and positive electrode 21 as negative electrode, positive and negative The electrodes 21, 10 are coated with a high dielectric constant material layer 22, and the positive and negative electrodes 21, 10 are electrically connected to the positive and negative electrodes of a high-voltage pulse power supply 23, so that dielectric barrier discharge occurs in the electric field 20. The electric field catalyst honeycomb carrier 30 made of several porous ceramics is placed in the electric field 20, and the catalyst honeycomb carrier 30 is filled with the first catalyst 31 loaded with TiO ₂ and Al ₂ O ₃ and loaded with V ₂ O ₅ and TiO ₂ The second catalyst 32. Immediately after the electric field 20, a section of non-electric field catalyst honeycomb carrier 40 is connected in series, filled with a third catalyst 41 loaded with MnO ₂ .

The mechanism of plasma purification of pollutants is that the spike pulse excites a large number of high-energy electrons, abundant ultraviolet rays, and a small amount of rays through silent discharge (high dielectric constant material blocking discharge), and the material atoms in this environment are inelastic to high-energy electrons. The collision causes the electrons in the outer layer of the gas atoms to oscillate and escape from the bondage of the atoms. This process will cause the chemical bonds to break and generate highly active excited state ions. At the same time, the energy of high-energy electrons and rays is absorbed by air molecules, which will produce strong oxidant O ₃ , highly active HO ₂ , OH free radicals and excimer O. The energy of all these excited state ions, strong oxidants, free radicals and excimers is greater than the molecular bond energy of organic matter, thus opening the chemical bonds of organic matter to undergo chemical reactions. The chemical formula of high-energy electron-excited active substances: H ₂ O+e ^- →H*+HO*+e ^- H*+O ₃ →OH*+O ₂ HO*+O ₃ →HO ₂ *+O ₂ HO ₂ *+ O ₃ →HO*+2O ₂ .

The catalyst honeycomb carrier is a porous ceramic body with excellent adsorption performance and high dielectric constant, which has preferential adsorption for organic matter, so it can enrich organic matter in its body, and desorb the degradation products after the organic matter is completely degraded; porous ceramics The body can also enrich short-lived active substances such as free radicals and excimers, which means that organic matter and active substances are enriched in specific areas, thereby increasing the probability of organic matter degradation; porous ceramic bodies with high dielectric constant are in the electronic and Under the radiation bombardment, the porous surface is excited into active centers, which is beneficial to the degradation of organic matter. the

AL ₂ O ₃ and V ₂ O ₅ as conventional catalysts can significantly increase the degradation rate of organic matter and make the reaction proceed in the desired redox direction. The role of MnO ₂ is to accelerate O ₃ →O ₂ +O*, and use O* to degrade organic matter. _TiO2 is an N-type semiconductor. The energy band of _TiO2 particles used as a catalyst is discontinuous, and its energy band structure consists of a low-energy valence band (VB) full of electrons and an empty high-energy conduction band (CB). , electrons are delocalized in the valence and conduction bands and can move freely. In an ideal _TiO2 semiconductor, there is no electronic state in the band gap between the top of the valence band and the bottom of the conduction band. This band gap is called the forbidden band, and the forbidden band width is represented by Eg.

Due to the inevitable existence of impurities and various traps in the actual _TiO2 semiconductor, electrons and holes are bound around it, becoming traps for capturing electrons and holes, resulting in localized electronic states, and introducing corresponding electrons in the forbidden band state energy level. As shown in Figure 2, taking the point defect in the particle crystal as an example, in the positive center, the negative ion vacancies and the positive ions in the gap are all positive centers. The positive center binds an electron, and the bound electron is easy to break free and become Free electrons in the conduction band. As shown in Figure 3, nanometer-sized _TiO2 absorbs photons and high-energy electrons with energy greater than or equal to Eg, and electrons will transition from the valence band to the conduction band, thereby generating holes h+ in the valence band and electrons e- in the conduction band. , driven by the electric field of the reactor, the electrons and holes migrate to different positions on the surface of the particle, and they can undergo redox reactions with the substances adsorbed on the surface of the catalyst particle under the action of the electric field or through diffusion, or directly recombine. As shown in Figure 3, in the main steps of the TiO ₂ plasma catalytic reaction, ① TiO ₂ is excited by high-energy electrons and ultraviolet rays to generate electron-hole pairs; ③Oxidation reaction induced by valence band holes; ④Reduction reaction induced by conduction band electrons; ^⑤Further catalytic reaction occurs; group. The superoxide free radical formed in reaction ④ has a strong oxidizing ability and plays a speed-determining role in the degradation of the entire organic matter. In the absence of an electric field, the occurrence probability of reaction ② is the main one, but after the TiO ₂ catalyst is placed in a high-voltage pulsed electric field, it can force the excited electrons to move to the positive electrode of the electric field, thereby significantly weakening the reaction ②, making the required The responses of ③④⑤ were significantly enhanced.

As known to those skilled in the art, the accompanying drawings and embodiments of the present utility model only illustrate the function, structure and principle of the present utility model and should not be limitations on the understanding of the invention; meanwhile, the purpose of the utility model is has been achieved. The above embodiments may be changed without departing from the principle of the utility model, therefore, the protection of the utility model shall be based on the scope described in the claims. the

Claims (1)

1. organic gas plasma catalytic device; It is characterized in that comprising a shell (10); The parallel connection or a plurality of electric fields (20) of connecting in the shell (10); Electric field (20) is made up of shell (10) and positive electrode (21) as negative electrode; All apply high dielectric constant material layer (22) on the positive and negative electrode (21,10) and be electrically connected to the positive and negative electrode of a high-voltage pulse power source (23) separately, the electric field catalysis agent honeycomb substrate (30) that placement is processed by several porous ceramics in electric field (20) is filled first catalyst (31), second catalyst (32) respectively in the catalyst monolith carrier (30); Be close to electric field series connection one section non-electric field catalyst monolith carrier (40) afterwards at electric field (20), fill the 3rd catalyst (41).

Images