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Classification of industrial waste gas and common technical solutions for waste gas treatment

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Waste gas treatment is generally divided into organic waste gas (VOC waste gas and organic compounds) and inorganic waste gas treatment, odor elimination. The following factors should be considered in general: the type and concentration of organic pollutants, the exhaust temperature and emission flow of organic waste gas, the content of particulate matter and the level of pollutant control that needs to be achieved. Special care must be taken when the organic waste gas contains a high concentration of substances that can convert organic acids (such as chlorine, fluorine, sulfur and halogens). They can cause severe corrosion to equipment or poison the catalyst. (1) organic waste gas treatment components:

Waste gas treatment is generally divided into organic waste gas (VOC waste gas and organic compounds) and inorganic waste gas treatment, odor elimination.
1 Organic waste gas
When choosing the treatment method of organic waste gas, the following factors should be considered in general: the type and concentration of organic pollutants, the exhaust temperature and emission flow of organic waste gas, the content of particulate matter, and the level of pollutant control that needs to be achieved.
Special care must be taken when the organic waste gas contains a high concentration of substances that can convert organic acids (such as chlorine, fluorine, sulfur and halogens). They can cause severe corrosion to equipment or poison the catalyst.
(1) organic waste gas treatment components:
Organic waste gas treatment refers to the adsorption, filtration and purification of organic waste gas produced in the process of industrial production. Organic waste gas mainly includes various hydrocarbons, alcohols, aldehydes, acids, ketones and amines.
In general, organic waste gas treatment includes formaldehyde organic waste gas treatment, benzene series organic waste gas treatment such as benzene benzene benzene, acetone butanone organic waste gas treatment, ethyl acetate waste gas treatment, oil mist organic waste gas treatment, furfural organic waste gas treatment, styrene, acrylic acid organic waste gas treatment, resin organic waste gas treatment, additive organic waste gas treatment, paint mist organic waste gas treatment, Tina water organic waste gas treatment and other organic compounds such as carbon hydrogen oxygen and air purification treatment.
(2) organic waste gas treatment characteristics
The main characteristics of organic waste gas: organic waste gas is usually easy to burn, easy to explode, toxic, can not be dissolved in water, can be dissolved in organic solvents, the degree of difficulty is relatively large.
(3) the introduction of the treatment method of organic waste gas
At present, in the process of organic waste gas treatment, the most common method is the organic waste gas activated carbon adsorption treatment method, catalytic combustion treatment method, catalytic oxidation treatment method, acid-base neutralization method, plasma treatment method and many other different principles and methods.
However, the current plasma treatment method has the problem of high-voltage discharge, some industries are prone to the dangerous characteristics of explosion, and the late cost of activated carbon is high.
Plasma treatment technology: the use of double dielectric barrier discharge in the form of plasma, the density of the plasma generated is 1500 times the density of the plasma generated by other technologies, initially used for the decomposition of Freon, Halon substances, and then extended to the industrial odor, odor, toxic and harmful gas treatment.
The technology is energy-saving, environmentally friendly, and has a wide range of applications. Almost all the odorous odors generated in all chemical production links can be processed, and it has a good decomposition effect on dioxins.
Activated carbon adsorption waste gas treatment: mainly use the active adsorption device to filter and adsorb the organic waste gas and dust in the waste gas, so as to achieve the effect of purifying the organic waste gas and removing dust. The adsorption device is a more traditional waste gas treatment method. In the past few years, many companies used this device.
At present, the methods of treating organic waste gas mainly include adsorption method, catalytic combustion method, activated carbon adsorption, catalytic combustion method and absorption method. Consider the feasibility of the method, operating costs, equipment investment costs, and secondary pollution issues appropriate selection of treatment.
Before the industrial waste gas treatment equipment is mainly the use of filtration and adsorption method, filtration using medium-effect filtration, adsorption using activated carbon adsorption, material microporous and huge surface tension and other characteristics of the waste gas in the removal of organic substances, including methods of filtration, adsorption, ozone disinfection. The use of activated carbon itself high-strength adsorption force, combined with the fan effect of organic waste gas molecules adsorption, benzene, alcohols, ketones, esters, gasoline and other organic solvents have a good adsorption of waste gas.
2 Inorganic waste gas
2.1 inorganic waste gas components
Inorganic waste gas is divided into organic waste gas, inorganic waste gas and dust-containing waste gas according to its nature, organic waste gas such as methyl, dimethyl, etc., inorganic waste gas such as HCl, H2S, NOX, etc., dust-containing waste gas such as oxidation dust in the smelting process of various metals, stone dust in the process of ore processing, and so on. Inorganic waste gas mainly includes sulfur oxides, nitrogen oxides, carbon oxides, halogens and their compounds, etc.
2.2 inorganic waste gas treatment technology
The treatment of inorganic waste gases such as HCl is generally treated by liquid spray absorption. H2S is also treated by a photolytic process. Dust and other gas treatment technology Dust is generally based on cyclone/bag/electrostatic dust removal, and different treatment processes are selected according to needs.
3 Odor and VOCs
There are many kinds of odor gases, usually including sulfur, nitrogen, oxygen and hydrocarbons and other compounds, divided into organic and inorganic two categories, specifically:
(1) Sulfur-containing compounds, such as hydrogen sulfide, carbon disulfide, mercaptan, sulfide, methyl sulfur;
(2) nitrogen compounds, such as ammonia, trimethylamine, amide, indole, etc;
Hydrocarbons: such as alkanes, olefins, aromatic hydrocarbons, halogenated hydrocarbons;
Oxygen-containing organic compounds: such as alcohols, phenols, aldehydes, ketones, organic acids, etc;
Benzene: such as benzene, toluene, xylene, coking benzene, etc.
Common odor gas composition characteristics:
Component molecular formula characteristics
Amine CH3NH2(CH3)N gas, soluble in water, soluble in alcohol, ether, benzene and other organic solvents, fishy smell
Ammonia NH3 gas, soluble in water, soluble in alcohol, ether, benzene and other organic solvents, stimulating taste
Methyl mercaptan CH4S gas, insoluble in water, soluble in alcohol, ether, benzene and other organic solvents
Methyl sulfide C2H6S liquid, insoluble in water, soluble in alcohol, ether, benzene and other organic solvents
Hydrogen sulfide H2S gas, soluble in water, soluble in alcohol, ether, benzene and other organic solvents, rotten egg smell
Carbon disulfide CS2 gas, insoluble in water, soluble in alcohol, ether, benzene and other organic solvents, stimulating taste
For the treatment of odor and peculiar smell, targeted selection should be made for different waste gas components. For example, water spray treatment scheme should be used for those that are easily soluble in water. For waste gas containing complex components such as hydrogen sulfide, ammonia and methyl sulfide, water spray and photo-oxygen catalytic comprehensive waste gas treatment scheme should be used, the spray tower first treats some waste gas dissolved in water and removes dust and some solid particles, paint mist in the painting process, high temperature smoke in the smelting process, black mist in the plastic granulation process, etc., and then the photo-oxygen device or plasma device can treat organic or inorganic waste gas such as other aromatic hydrocarbons and hydrogen sulfide.
At present, due to the composition of industrial waste gas is more and more complex, a single waste gas treatment technology is difficult to achieve the ideal treatment effect. Integrated two or more than two kinds of processing technology equipment because of the small footprint, processing efficiency is more and more concerned by the relevant professionals.