CN111437719B

CN111437719B - Device for degrading VOCs (volatile organic compounds) by low-temperature plasma in cooperation with catalysis

Info

Publication number: CN111437719B
Application number: CN202010175007.2A
Authority: CN
Inventors: 周金堂
Original assignee: Suzhou Jinyaomiao Environmental Technology Co ltd
Current assignee: Suzhou Jinyaomiao Environmental Technology Co ltd
Priority date: 2020-03-13
Filing date: 2020-03-13
Publication date: 2022-07-22
Anticipated expiration: 2040-03-13
Also published as: CN111437719A

Abstract

The invention relates to a device for degrading VOCs (volatile organic compounds) by low-temperature plasma in a synergetic catalytic manner, which comprises a pretreatment mechanism and a plasma generator connected to the end part of the pretreatment mechanism, wherein the plasma generator comprises a plurality of plasma reaction tubes arranged in parallel, an inner electrode arranged in the plasma reaction tubes, a coil-type electrode wound on the outer surface of the plasma reaction tubes and a high-voltage power supply connected with the inner electrode, the plasma reaction tubes comprise reaction tube bodies, a plurality of purification cavities are arranged on the outer walls of the reaction tube bodies, a first baffle plate is detachably arranged between each purification cavity and the reaction tube bodies, a plurality of first vent holes are formed in the first baffle plate, and a catalyst is filled in each purification cavity. The invention has the characteristics of simple and compact structure, high efficiency of catalyzing and degrading VOCs waste gas and thorough purification.

Description

Device for degrading VOCs (volatile organic compounds) by low-temperature plasma in cooperation with catalysis

Technical Field

The invention relates to the technical field of waste gas treatment, in particular to a device for degrading VOCs (volatile organic compounds) through low-temperature plasma concerted catalysis.

Background

At present, Volatile Organic Compounds (VOCs) emitted by industry and agriculture are one of important air pollution sources,

the harm is mainly divided into two types, one is direct harm, and the direct harm stimulates the respiratory system of human and animals to cause pathological changes; and the other is secondary hazard, VOCs are easy to cause a series of photochemical reactions in the air to cause disasters such as haze, photochemical smog and the like, so that the health of human beings is greatly threatened.

In the existing VOCs treatment and purification methods, the more traditional control method such as a burning method consumes serious energy and is easy to generate serious secondary pollution; although the catalytic combustion method is effective to organic pollution, the problems of large air resistance and low efficiency still exist in the treatment of large-flow and high-flow-rate waste gas; the adsorption-desorption method also has the problems of adsorption capacity, air resistance and universality. In recent years, means such as membrane separation, biodegradation, and condensation have been developed to effectively improve the recyclability, but the efficiency of treating VOCs has not been substantially improved.

The low-temperature plasma technology is to make high-activity particles generated by gas discharge collide with pollutant molecules to dissociate and oxidize the pollutant molecules, thereby achieving the purpose of waste gas purification. In recent years, low-temperature plasma technology is widely applied to treatment of low-concentration waste gas containing VOCs and odorous gas, the overall application effect is good, but the development of the technology still has limitations. The treatment technology still has the characteristics of easy formation of byproducts, low energy efficiency and poor selectivity. The characteristics of high selectivity, high degradation efficiency and the like of the catalyst enable researchers to combine the catalyst with the catalyst, and the plasma treatment technology and the catalyst are used for treating harmful gases in a synergistic manner, so that the advantages and effects of the catalyst are successfully applied to the aspect of treating VOCs by using plasma. For example, the treatment effect of low-temperature plasma on toluene and propane can be greatly improved by combining the low-temperature plasma technology with an adsorption process and utilizing the adsorption effect of the microporous gamma-Al 2O3 particles; the removal rate of benzene, toluene, ethanol and dichloroethane can be improved by about 20% by combining the metal oxides with higher catalytic activity such as Mn, Fe and the like with the plasma technology; the low-temperature plasma and the photocatalysis technology are combined, on one hand, the VOCs degradation efficiency of the low-temperature plasma can be greatly improved through photocatalysis, on the other hand, the plasma can effectively inhibit the inactivation of the catalyst, and the method is particularly suitable for treating the high-flow and low-concentration VOCs (generally lower than 300mg/m 3) waste gas in the production and manufacturing industry of composite materials.

Disclosure of Invention

The invention aims to provide a device for degrading VOCs (volatile organic compounds) by cooperating low-temperature plasma with high degradation efficiency and thorough purification.

In order to achieve the purpose, the invention provides the following technical scheme: the utility model provides a low temperature plasma is catalytic degradation VOCs's device in coordination, its include pretreatment mechanism and connect in the plasma generator of pretreatment mechanism tip, plasma generator include a plurality of parallel arrangement's plasma reaction pipe, set up in inside inner electrode of plasma reaction pipe, around in the coil formula electrode of plasma reaction outside of tubes surface and with the high voltage power supply that the inner electrode links to each other, the plasma reaction pipe includes the reaction tube body, reaction tube body outer wall is equipped with a plurality of purification chambeies, purify the chamber with can dismantle between the reaction tube body and be equipped with first separation blade, set up a plurality of first air vents on the first separation blade, every purify the intracavity and fill the catalyst.

Every purify the chamber top be equipped with a charge door and with charge door sealing connection detachable top cap.

Pretreatment mechanism internally mounted has first packing layer and is located the second packing layer of first packing layer top, first packing layer with be equipped with the shower between the second packing layer, fixed a plurality of last shower and with go up the lower shower that the shower staggered each other on the shower, second packing layer top still is equipped with except that the fog layer.

The inner wall of the pretreatment mechanism is provided with a spiral guide plate, the spiral guide plate is positioned below the first packing layer, a water tank is arranged between the spiral guide plate and the first packing layer, and the spiral guide plate encloses an air inlet channel.

The pretreatment device comprises a pretreatment mechanism, a water tank and a water outlet, wherein the lower part of the pretreatment mechanism is provided with the water tank and the water outlet, the water tank is connected with a water pump, the water tank passes through the water outlet and is communicated with the inside of the pretreatment mechanism, the inlet of the water pump passes through a water pipe and is connected with the water tank, and the outlet of the water pump passes through a water pipe and is respectively connected with a spray pipe and a water tank.

And a gas flow meter is arranged between the pretreatment mechanism and the plasma generator.

The rear end of the plasma generator is connected with a fan, and the fan is connected with a chimney.

Compared with the prior art, the invention has the beneficial effects that: the pretreatment mechanism is favorable for preliminary purification of VOCs waste gas and removal of large particle substances; high voltage is applied to an inner electrode in the plasma reaction tube to generate active particles such as high-energy electrons, ions, free radicals and the like, so that VOCs (volatile organic compounds) exhaust gas molecules are excited and ionized in a very short time and are converted into harmless CO₂And H₂O; the catalyst that purifies the intracavity cooperates plasma to catalyze VOCs waste gas, and this internal VOCs waste gas of reaction tube produced's accessory substance and untreated VOCs waste gas can get into the purification chamber, through the further catalysis of catalyst, purifies the accessory substance of intracavity and can get into this internal quilt of reaction tube again and catalyze, and VOCs waste gas is through having enough to meet the need repeatedly thoroughly degradation, and purification efficiency is high, avoids secondary pollution.

Drawings

FIG. 1 is a schematic diagram of the overall structure of a device for the concerted catalytic degradation of VOCs by low-temperature plasma according to the present invention;

FIG. 2 is a schematic diagram of the pretreatment mechanism of FIG. 1;

FIG. 3 is a schematic view of a portion of the plasma purification assembly of FIG. 1;

fig. 4 is a schematic structural view of the purification chamber in fig. 1.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.

Referring to fig. 1 to 4, the apparatus for degrading VOCs by using low-temperature plasma in cooperation with catalysis of the present invention includes a pretreatment device 10 and a plasma generator 30 connected to an end of the pretreatment device 10. A gas flow meter 20 is provided between the pretreatment mechanism 10 and the plasma generator 30. The rear end of the plasma generator 30 is connected with a fan 40, and the fan 40 is connected with a chimney 50.

Referring to fig. 1, the pretreatment mechanism 10 includes a cavity 100, a first packing layer 11 and a second packing layer 12 located above the first packing layer 11 are installed inside the cavity 100, referring to fig. 2, a spray pipe 13 is arranged between the first packing layer 11 and the second packing layer 12, a plurality of upper spray headers 14 and lower spray headers 15 staggered with the upper spray headers 14 are fixed on the spray pipe 13, water is sprayed simultaneously from top to bottom, and the upper spray headers 14 and the lower spray headers 15 are staggered with each other, so that the water spraying area is increased. In addition, a demisting layer 16 is arranged above the second packing layer 12, and a spiral flow guide plate 17 is downward along the inner wall. The inner wall of the cavity 100 is provided with a spiral guide plate 17, the spiral guide plate extends from top to bottom around the inner wall, the spiral guide plate 17 is positioned below the first packing layer 11, a water tank 18 is arranged between the spiral guide plate 17 and the first packing layer 11, and the spiral guide plate 17 encloses an air inlet channel 19. The lower part of the cavity 100 is provided with a water tank 111 and a water outlet 112, the water outlet 112 is arranged on the cavity 100, and the water tank and the water outlet are both positioned below the spiral guide plate. The water tank 111 is connected with a water pump 113, the water tank 111 is communicated with the inside of the cavity 100 through a water outlet 112, an inlet of the water pump 113 is connected with the water tank 111 through a water pipe 114, and an outlet of the water pump 113 is respectively connected with the shower pipe 13 and the water tank 18 through the water pipe 114. The chamber 100 is further provided at both ends thereof with a spray inlet 115 and a spray outlet 116. When the device works, water in the water tank 18 overflows and flows down, water on the spiral guide plate 17 flows down, a water curtain is formed at the air inlet channel 19, and VOCs waste gas entering from the spraying air inlet 115 is primarily purified through the water curtain. The inner diameter of the cavity provided with the spiral guide plate is gradually reduced from top to bottom.

Referring to fig. 1 and 3, the plasma generator 30 includes an insulating housing 31 and a plasma purifying assembly 32 housed in the insulating housing 31. The plasma purifying assembly 32 includes a plurality of plasma reaction tubes 321 arranged in parallel, an inner electrode 322 disposed inside the plasma reaction tubes 321, a coiled electrode 323 wound around an outer surface of the plasma reaction tubes 321, and a high voltage power supply (not shown) connected to the inner electrode 322. The insulating housing 31 has a purge air inlet 311 and a purge air outlet 312 at both ends thereof. The plasma reaction tube 321 includes a reaction tube body 3211.

In this embodiment, referring to fig. 4, the outer wall of the reaction tube body 3211 is provided with a plurality of purification cavities 3212, a first blocking piece 3213 is detachably disposed between the purification cavities 3212 and the reaction tube body 3211, the first blocking piece 3213 is provided with a plurality of first ventilation holes 3214, and each purification cavity 3212 is filled with a catalyst. In order to facilitate filling the purifying cavities 3212 with catalyst, a charging opening 3215 and a detachable top cover 3216 hermetically connected to the charging opening 3215 are provided at the top of each purifying cavity 3212. The plurality of purification chambers 3212 may be filled with different catalysts, such as CuO, MnO₂And FeO, etc., in the catalyst, the lattice oxygen is easily activated by low-temperature plasma, and the oxidation reaction of the oxygen on the surface of the catalyst is promoted, so that the degradation is promoted. Such as Cu, Co, Fe, etc., which generate O by low-temperature plasma₃Active catalytic substances such as active oxygen atoms and hydroxyl groups are generated by decomposition, and the degradation of the VOCs waste gas is promoted. When the device works, high voltage is applied to the inner electrode to generate active particles such as high-energy electrons, ions, free radicals and the like, so that VOCs (volatile organic compounds) waste gas molecules are excited and ionized in a very short time and are converted into harmless CO₂And H₂O。The catalyst in the purification chamber 3212 assists the plasma to catalyze the VOCs waste gas, the byproduct generated by the VOCs waste gas in the reaction tube body 3211 and the untreated VOCs waste gas can enter the purification chamber 3212, the catalyst is used for further catalysis, the byproduct in the purification chamber 3212 can enter the reaction tube body 3211 again to be catalyzed, the VOCs waste gas is thoroughly degraded through repeated turnover, the purification efficiency is high, and the secondary pollution is avoided.

The working process is as follows: VOCs waste gas enters a pretreatment mechanism, water in a water tank overflows and flows down, water on a spiral guide plate flows down, a water curtain is formed at an air inlet channel, VOCs waste gas entering from a spraying air inlet is primarily purified through the water curtain, the primarily purified waste gas sequentially passes through a first filling layer, a second filling layer and a demisting layer, and is finally discharged to a plasma generator through a spraying air outlet; the catalyst in the plasma reaction tube is cooperated with the plasma to degrade the entering waste gas; and conveying the degraded product to a chimney through a fan, and finally discharging to the atmosphere.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. The utility model provides a device of low temperature plasma concerted catalysis degradation VOCs, its includes pretreatment mechanism and connect in the plasma generator of pretreatment mechanism tip, plasma generator include a plurality of parallel arrangement's plasma reaction pipe, set up in the inside inner electrode of plasma reaction pipe, around in the outer surface of plasma reaction pipe coil form electrode and with the high voltage power supply that the inner electrode links to each other, its characterized in that: the plasma reaction tube comprises a reaction tube body, a plurality of purification cavities are arranged on the outer wall of the reaction tube body, first blocking pieces are detachably arranged between the purification cavities and the reaction tube body, a plurality of first air vents are formed in the first blocking pieces, a catalyst is filled in each purification cavity, a space is reserved between the catalyst and the inner electrode, the purification cavities are distributed on two sides of the outer wall of the reaction tube body, the purification cavities on one side and the purification cavities on the other side are staggered mutually, a first packing layer and a second packing layer positioned above the first packing layer are arranged in the pretreatment mechanism, a spray pipe is arranged between the first packing layer and the second packing layer, a plurality of upper spray heads and lower spray heads staggered mutually with the upper spray heads are fixed on the spray pipe, and a defogging layer is further arranged above the second packing layer, the inner wall of the pretreatment mechanism is provided with a spiral guide plate, the spiral guide plate is positioned below the first packing layer, a water tank is arranged between the spiral guide plate and the first packing layer, the spiral guide plate is enclosed into an air inlet channel, the lower part of the pretreatment mechanism is provided with a water tank and a water outlet, the water tank is connected with a water pump, the water tank passes through the water outlet and the inside of the pretreatment mechanism is communicated, an inlet of the water pump passes through a water pipe and the water tank is connected, and an outlet of the water pump passes through the water pipe and is respectively connected with the spray pipe and the water tank.

2. The device for the concerted catalytic degradation of VOCs of claim 1, wherein: every purify the chamber top be equipped with a charge door and with charge door sealing connection detachable top cap.

3. The device for the concerted catalytic degradation of VOCs of claim 1, wherein: and a gas flow meter is arranged between the pretreatment mechanism and the plasma generator.

4. The device for the concerted catalytic degradation of VOCs of claim 3, wherein: the rear end of the plasma generator is connected with a fan, and the fan is connected with a chimney.