What are the classifications of waste gas treatment equipment?

Waste gas treatment equipment, mainly refers to the use of different processes and technologies, through recycling or removing, reducing the harmful components of exhaust emissions, to protect the environment, a kind of environmental equipment to purify the air, so that our environment is not polluted.

Classification:

The absorption equipment

The absorption method USES low-volatile or non-volatile solvents to absorb VOCs, and the physical properties of VOCs and absorbent are separated.

The bottom of the self-absorption tower containing VOCs enters the tower, and in the process of rising, it comes into contact with the absorber from the top of the tower countercurrent, and the purified gas is discharged from the top of the tower. After absorbing VOCs through the heat exchanger, it enters the top of the stripper and is desorbed when the temperature is higher than the absorption temperature or the pressure is lower than the absorption pressure. After desorption, the absorbent condenses through the solvent condenser and returns to the absorber. After the desorption VOCs gas passes through the condenser and gas-liquid separator, it leaves the stripper tower as pure VOCs gas and is recycled. This process is suitable for the gas purification with higher VOCs concentration and lower temperature. In other cases, corresponding process adjustment is required.

Adsorption equipment

When a fluid mixture is treated with a porous solid substance, a component or components of the fluid can be sucked onto the surface and concentrated on it. This phenomenon is called adsorption. During the adsorption of waste gas, the object of adsorption is gaseous pollutant and gas-solid adsorption. The adsorbed gas components are called adsorbents, and the porous solids are called adsorbents.

After adsorbents are adsorbed on the solid surface, a adsorbed adsorbent can be detached from the adsorbent surface. However, after adsorption for a period of time, due to the concentration of surface adsorbents, the adsorption capacity of adsorbents decreased significantly, and the adsorption and purification requirements, at this time, it is necessary to take certain measures to desorption adsorbents adsorbed on the adsorbent, in order to assist the adsorption capacity, this process is called adsorbent regeneration. Therefore, in the actual adsorption engineering, the waste gas treatment equipment manufacturers of paper mills just use the recycling process of adsorption, recycling and adsorption to remove the pollutants in the waste gas and recover the useful components in the waste gas.

Purification equipment

Combustion is effective in treating high concentrations of vocs and odorous compounds. The principle is that excess air is used to burn these impurities, most of which produce carbon dioxide and water vapor, which can be discharged into the atmosphere. However, when organic compounds containing chlorine and sulfur are treated, HCl or SO2 in the product is produced by combustion, which requires further treatment of the gas after combustion.

Processing principle:

Dilution diffusion method

Principle: the smelly ground gas is discharged into the atmosphere through the chimney, or diluted with odorous air to reduce the concentration of odorous substances to reduce the odor. Scope of application: suitable for the treatment of medium, low concentration of organized emissions of odor gas. Advantages: low cost, simple equipment. Disadvantages: subject to meteorological conditions, odorous substances still exist.

The water absorption

Principle: make use of the characteristics of some substances soluble in water in the odor, make the components of odor directly contact with water, so as to dissolve in water to achieve the purpose of deodorization. Scope of application: water soluble odorous gas with organized emission source. Advantages: simple process, convenient management, low equipment operating cost to produce secondary pollution, need to deal with the washing liquid. Disadvantages: low purification efficiency, should be used in combination with other technologies, poor treatment effect of mercaptan, fatty acid.

Aeration deodorization

Principle: the odor substances are dispersed to the mixture containing activated sludge in the form of aeration, and the application scope is wide through the suspension growth of microorganisms to degrade the odor substances. Scope of application: as of 2013, it has been used to treat odors in feces treatment plants and sewage treatment plants in Japan. Advantages: after the acclimatization of activated sludge, the removal rate of odor components can reach 99.5%. Disadvantages: limited by the strength of aeration, the application of this method is also limited.

Catalytic oxidation process

Principle: the reaction tower is filled with special solid packing, and the inside of the packing is compounded with multi-medium catalyst. When the stench gas passes through the packing layer under the action of the induced draft fan, it makes full contact with the liquid phase compound oxidant ejected by the special nozzle in a mist on the solid phase packing surface, and the pollution factors in the stench gas are fully decomposed under the catalysis of the multi-medium catalyst. Scope of application: wide scope of application, especially for the treatment of large gas volume, high concentration of exhaust gas, hydrophobic pollutants have a good removal rate. Advantages: small footprint, low investment, low operating cost; Easy to manage, out of the box. Disadvantages: shock load resistance, not easy to pollutant concentration and temperature changes, need to consume a certain amount of agents.