Air emission control technology refers to a series of control measures and technologies made in response to the increasingly serious air pollutants, including basic methods, purification equipment and technological processes.

General purification technology

(1) Absorption method
Using liquid as absorbent, the target pollutants are absorbed after the exhaust gas contacts with it, so that the gas is purified. The absorption process is generally carried out in an absorption scrubber tower. This method can handle a variety of harmful gases, has a wide range of applications, and has low one-time investment, which is easy to cause secondary pollution, and generally has a low absorption efficiency.

(2) Adsorption method
The surface porous solid material (adsorbent) is brought into contact with the exhaust gas, and the harmful components are adsorbed to achieve the purpose of purification. Divided into physical adsorption and chemical adsorption, high purification efficiency, suitable for low concentration occasions, often used for deep purification or the final control of several purification methods, but the adsorbent needs to be regenerated.
(3) Condensation method
The recovered material by this method is relatively pure and suitable for the treatment of high-concentration harmful gases. It is usually used as the pretreatment of the adsorption method to reduce the processing load of the adsorption method, or to remove harmful components in advance to prevent corrosion of equipment and affect subsequent operations, or pre-recovery Certain available pure substances.
(4) Catalytic method
Divided into catalytic oxidation and catalytic reduction. A method of converting harmful components into harmless or easy-to-remove substances using the catalytic action of catalysts. The method has high efficiency and no secondary pollution, but the catalyst price is high and the operation requirements are high.
(5) Combustion method
Divided into direct combustion and catalytic combustion. The method of oxidative combustion or pyrolysis of mixed gas to convert harmful components into harmless substances. No substances can be recovered, only the energy after combustion can be recovered.

The purification method of sulfur dioxide

(1) Fuel desulfurization
(2) Desulfurization during combustion
(3) Flue gas desulfurization

NOx purification method

(1) Fuel denitrification
(2) Denitrogenation in the combustion process: It refers to improving the combustion method by reducing the temperature of the flame during the combustion process or reducing the amount of air during combustion to suppress the formation of NOx, that is, low NOx combustion technology.
(3) Flue gas denitrification: The generated NOx is reduced to N2 or absorbed and converted into other substances through some measures, thereby reducing the emission of NO2.

Reduce or prevent emissions of air pollutants.

(1) Reform the energy structure and adopt non-polluting energy (such as solar energy, wind power, water power) and low-polluting energy (such as natural gas, biogas, alcohol).
(2) Pretreatment of fuel (such as fuel desulfurization, liquefaction and gasification of coal) to reduce substances that pollute the atmosphere during combustion.
(3) Improve combustion devices and combustion technologies (such as reforming stoves, using boiling furnaces for combustion, etc.) to improve combustion efficiency and reduce harmful gas emissions.
(4) Adopt non-polluting or low-polluting industrial production processes (such as no and less use of raw materials that are likely to cause pollution, closed-circuit circulation processes, etc.).
(5), save energy and carry out comprehensive utilization of resources.
(6) Strengthen enterprise management and reduce accidental emissions and fugitive emissions.
(7) Timely clean up and properly dispose of industrial, domestic and construction waste residues to reduce ground dust.

Develop plant purification.

Plants have the functions of beautifying the environment, regulating the climate, trapping dust, and absorbing harmful gases in the atmosphere. They can purify the atmosphere for a long time and continuously in a large area.

Especially when the pollutants in the atmosphere have a wide range of influence and low concentrations, plant purification is an effective method. Planned and selective expansion of green space in cities and industrial areas is a long-term and multi-functional measure for comprehensive air pollution prevention and control.

Use the self-purification ability of the environment.

The self-purification of the atmospheric environment has physical, chemical effects (diffusion, dilution, oxidation, reduction, precipitation washing, etc.) and biological effects. Under the condition that the total amount of pollutants discharged is constant, the distribution of pollutant concentrations in time and space is related to meteorological conditions. Understanding and mastering the laws of meteorological changes and making full use of the self-purification ability of the atmosphere can reduce the concentration of pollutants in the atmosphere and avoid Or reduce air pollution hazards.