CN216521722U

CN216521722U - Low concentration VOCs exhaust treatment device

Info

Publication number: CN216521722U
Application number: CN202123362840.7U
Authority: CN
Inventors: 马军; 刘新文; 黄毅烽
Original assignee: Guangzhou Heima Technology Co ltd
Current assignee: Guangzhou Heima Technology Co ltd
Priority date: 2021-12-28
Filing date: 2021-12-28
Publication date: 2022-05-13
Anticipated expiration: 2031-12-28

Abstract

The utility model provides a low-concentration VOCs (volatile organic compounds) waste gas treatment device which comprises a dehumidification heat pump, an ozone generator and a catalytic bed, wherein the dehumidification heat pump and the catalytic bed are sequentially connected in series through a pipeline, a bypass is connected to the pipeline between the dehumidification heat pump and the catalytic bed, and the bypass is connected to the ozone generator. The utility model fully reduces the operation cost, has lower equipment cost, high treatment efficiency and effectively reduced odor concentration, and has good operation performance and outstanding technical advantages.

Description

Low concentration VOCs exhaust treatment device

Technical Field

The utility model relates to the technical field of air treatment, in particular to a low-concentration VOCs waste gas treatment device.

Background

The industrial production will emit a large amount of Volatile Organic Compounds (VOCs) with low concentration, for example, the waste gas generated in the production of feed, essence and flavor, biological fermentation drug, magnetic electronic material, injection molding process and the like are all waste gas with low concentration of VOCs, and the VOCs in the waste gas are usually 200mg/m³。

Traditionally, the waste gas is treated by adopting a molecular sieve rotating wheel for concentration to separate the waste gas into two parts, one part is relatively clean air containing trace VOCs, the waste gas is directly exhausted, the other part is waste gas containing high-concentration VOCs, and the waste gas is subjected to thermal combustion or catalytic combustion treatment and then exhausted to the atmosphere.

The traditional treatment method has the defects of large equipment investment and high operation cost, and sometimes the concentration of the odor of the waste gas treated by the rotary wheel can hardly reach the odor index regulated by the state.

As is well known, ozone can oxidize VOCs, and the principle of ozone oxidation VOCs is O₃Active O, which is a strong oxidant, is produced, which oxidizes VOCs to water and carbon dioxide. However, O at ordinary temperature₃It is difficult to instantaneously generate active O, and therefore, the effect of ozone to directly oxidize VOCs is limited.

Disclosure of Invention

The utility model aims to provide a low-concentration VOCs waste gas treatment device aiming at the technical defects in the prior art so as to solve the technical problems of large equipment investment and high operation cost in the traditional treatment method.

The utility model also aims to solve the technical problem that the concentration of the odor of the waste gas treated by the traditional rotating wheel is still higher.

The utility model also solves the technical problem that when O is adopted₃Oxidation of VOCs with oxygen at ambient temperature₃It is difficult to instantaneously generate active O.

In order to achieve the technical purpose, the utility model adopts the following technical scheme:

the utility model further provides a low-concentration VOCs waste gas treatment device which comprises a dehumidification heat pump, an ozone generator and a catalytic bed, wherein the dehumidification heat pump and the catalytic bed are sequentially connected in series through a pipeline, and a bypass is connected to the pipeline between the dehumidification heat pump and the catalytic bed and connected to the ozone generator.

Preferably, the dehumidification heat pump comprises a heat pump evaporator, a heat pump condenser, a refrigeration compressor and a refrigeration expansion valve, wherein the heat pump evaporator is located at the upstream of the heat pump condenser, and the refrigeration compressor and the refrigeration expansion valve are respectively connected between the heat pump evaporator and the heat pump condenser.

The method for treating the low-concentration VOCs waste gas by using the device comprises the following steps: the method comprises the following steps of (1) enabling the temperature of waste gas containing VOCs to be reduced to be below 20 ℃ through an evaporator of a dehumidification heat pump, enabling the temperature of the waste gas to be increased to be above 60 ℃ through a condenser of the heat pump, adding ozone into the waste gas after a heat pump dehumidifier, fully mixing, and enabling the mixed gas to enter a catalytic bed; the catalyst bed is filled with a catalyst, and the catalyst takes manganese oxide, copper oxide or cerium oxide as an active material and takes a molecular sieve or a porous material as a carrier.

Preferably, the molecular sieve is a ZSM-5 type molecular sieve, a beta type molecular sieve or a Y type molecular sieve.

Preferably, the porous material is activated carbon.

To overcome O at normal temperature₃The utility model discloses a catalyst, which takes manganese oxide, copper oxide and cerium oxide as active materials and takes porous materials such as ZSM-5, beta, Y-shaped molecular sieves or active carbon as carriers. Tests show that ozone O₃After the catalyst is contacted with the catalyst, active O is generated instantly, the catalyst is sensitive to humidity and temperature, and tests show that the catalyst has the best effect when the dew point temperature of air is lower than 20 ℃ and the temperature is higher than 60 ℃.

Based on the catalyst, the method for treating the waste gas of the low-concentration VOCs by using the device of the utility model comprises the following steps: the temperature of the waste gas containing VOCs is reduced to be below 20 ℃ after passing through an evaporator of a dehumidification heat pump, namely the temperature of T1 in figure 1 is below 20 ℃, the lower the temperature is, the better the treatment effect is, then the temperature of the waste gas is increased to be above 60 ℃ after passing through a condenser of the heat pump, namely the temperature of T2 in figure 1 is above 60 ℃, the higher the temperature is, the better the treatment effect is, ozone generated by an ozone generator is added into the waste gas after passing through a heat pump dehumidifier and is fully mixed, then the mixed gas enters a catalytic bed, and the VOCs in the waste gas are changed into water and carbon dioxide under the combined action of the ozone and a catalyst.

The higher the ozone concentration in the present invention, the better the treatment effect, but the most economical ozone concentrations are: the ratio of the concentration of VOCs to the concentration of ozone is approximately between 1-2, depending on the composition of the VOCs.

The waste gas treatment process of the utility model comprises a dehumidification heat pump, an ozone generator and a catalyst, wherein the dehumidification heat pump has the function of reducing air humidity and heating waste gas to be treated, and the catalyst has the function of enabling ozone to rapidly generate active O. The catalyst of the utility model takes manganese oxide, copper oxide and cerium oxide as active materials, and takes porous materials such as ZSM-5, beta, Y-type molecular sieves or active carbon and the like as carriers. The heat pump may reduce the exhaust gas temperature to below 20 ℃ and heat the exhaust gas temperature to above 60 ℃.

Practical application shows that the utility model is used for treating magnetic material waste gas and treating 15000m³The power of the/h air flow waste gas ozone generator is 25KW, the same type of waste gas is treated by the rotating wheel concentration catalytic combustion device, and the heating power of a catalytic bed exceeds 50KW, so the utility model has the advantage of low operation cost.

Drawings

FIG. 1 is a device for treating VOCs-containing waste gas according to the present invention;

in the figure:

1. heat pump evaporator 2, heat pump condenser 3, refrigeration compressor 4, refrigeration expansion valve

5. Ozone generator 6, catalytic bed.

Detailed Description

Hereinafter, specific embodiments of the present invention will be described in detail. Well-known structures or functions may not be described in detail in the following embodiments in order to avoid unnecessarily obscuring the details. Approximating language, as used herein in the following examples, may be applied to identify quantitative representations that could permissibly vary in number without resulting in a change in the basic function. Unless defined otherwise, technical and scientific terms used in the following examples have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

In addition to the functional magnetic material, the raw material for producing the magnetic electronic element is added with about 0.05% of dispersing agent, about 0.85% of binding agent and 0.07% of water temperature release agent. Typically, the dispersing agent is n-butanol or glycerol, the release agent is zinc stearate, and the binder is polyvinyl alcohol (PVA for short).

After the magnetic material is formed, degreasing treatment is needed, and the temperature is gradually increased to 1100 ℃ from the normal temperature. The dispersant and the release agent gradually volatilize during the temperature rise, but the binder PVA is decomposed.

PVA is heated to over 100 ℃ in the air, and then slowly discolors and embrittles; at the temperature of more than 150 ℃, the material can be fully softened and melted; the color will become very dark when heated to above 160 ℃; the color is darker at the temperature of more than 170 ℃; heating to above 220 deg.C, quickly decomposing polyvinyl alcohol to generate acetic acid, acetaldehyde, butenol and water; polyvinyl alcohol which is not decomposed until 250 ℃ or more becomes a polymer having conjugated double bonds. The decomposition rate of polyvinyl alcohol is influenced by factors such as heating temperature, holding time, oxygen content in the atmosphere, and vapor pressure of the decomposition product.

The temperature at which polyvinyl alcohol starts to decompose in air is around 230 ℃ and in oxygen 180 ℃. If the oxygen content in the atmosphere is too low, the temperature at which decomposition starts increases. The polyvinyl alcohol has different specifications and varieties, the proportion of two chemical structures is different, the initial decomposition temperature and the decomposition curve are different to a certain extent, and the initial decomposition temperature difference can reach about 80 ℃. The PVA decomposition reaction formula is as follows:

(CH₂CHOH)n+0₂→CH₃COOH+CH₃CHO+CH₃CH＝CHCHO+H₂O

the water produced after decomposition forms superheated steam. The acetic acid, acetaldehyde and crotonaldehyde produced are also superheated vapors. Whether or not they are burned depends on the temperature in the kiln, the oxygen content, etc. The natural point of acetaldehyde vapor in air is 156 ℃, and the acetaldehyde vapor can be combusted when meeting oxygen in the air after being decomposed to generate CO₂And superheated steam.

The odor substance produced by the magnetic material is acetaldehyde and crotonaldehyde.

Crotonaldehyde, a colorless transparent flammable liquid, has a suffocating pungent odor, and acetaldehyde (acetaldehyde), an aldehyde, also known as acetenal, is a colorless flowable liquid having a pungent odor. The elimination of crotonaldehyde and acetaldehyde in the exhaust gas is the key to solve the odor of the waste gas in the production of magnetic materials.

By using the method for treating the waste gas generated in the production of the electromagnetic electronic element, the odor concentration can be reduced from 3770 (dimensionless) to 601 (dimensionless) to meet the national emission standard.

The embodiments of the present invention have been described in detail, but the description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the utility model. Any modification, equivalent replacement, and improvement made within the scope of the application of the present invention should be included in the protection scope of the present invention.

Claims

1. The low-concentration VOCs waste gas treatment device is characterized by comprising a dehumidification heat pump, an ozone generator and a catalytic bed, wherein the dehumidification heat pump and the catalytic bed are sequentially connected in series through a pipeline, and a bypass is connected to the pipeline between the dehumidification heat pump and the catalytic bed and is connected to the ozone generator.

2. The apparatus of claim 1, wherein the dehumidification heat pump comprises a heat pump evaporator, a heat pump condenser, a refrigeration compressor, and a refrigeration expansion valve, wherein the heat pump evaporator is located upstream of the heat pump condenser, and the refrigeration compressor and the refrigeration expansion valve are respectively connected between the heat pump evaporator and the heat pump condenser.