The advantages, disadvantages and difficulties of VOCs treatment technology

In recent years, VOCs treatment has aroused the attention of all walks of life. VOCs, volatile organic compounds, are a general term of chemical substances and have high vapor pressure under normal temperature and pressure.

The composition of VOCs is complex and mainly includes alkanes, alkenes, aromatic hydrocarbons, halogenated hydrocarbons, oxygenated hydrocarbons, nitrogenous hydrocarbons, sulfurous hydrocarbons and low boiling point polycyclic aromatic hydrocarbons. The common types of VOCs are toluene, xylene, p-dichlorobenzene, ethylbenzene, styrene, formaldehyde, acetaldehyde and so on.

Sources of VOCs

VOCs emission sources are divided into natural and man-made sources. On the global scale, VOCs emissions are dominated by natural sources; however, anthropogenic emissions are much higher than those of natural sources in key regions and cities, which is 6-18 times of that of natural sources. In urban areas, the natural sources of VOCs are mainly green vegetation, which basically belongs to the uncontrollable source. The anthropogenic sources mainly include incomplete combustion, solvent use, industrial processes, volatile oil products and biological effects. Artificial sources mainly include incomplete combustion line, solvents used in industrial process oil volatilization and biological production. Artificial sources mainly include incomplete combustion line, solvents used in industrial process oil volatilization and biological production. Artificial sources mainly include incomplete combustion line, solvents used in industrial process oil volatilization and biological production. At present, China's VOCs emissions mainly come from fixed source combustion, road traffic solvent products and industrial processes. Mainly from fixed source combustion, road traffic solvent products and industrial processes. Mainly from fixed source combustion, road traffic solvent products and industrial processes. Among many anthropogenic sources, industrial sources are the main source of VOCs pollution, which has the characteristics of concentrated emissions, high emission intensity, high concentration and complex components.

VOCs hazards

VOCs on the human body there are two main hazards: one of its harmful components directly affect human health, the second VOCs will form PM2.5 precursors, which indirectly affect human health.

VOCs prevention and control technology

According to the principle of VOCs in the atmosphere and the physical and chemical properties of VOCs, the control technology can be divided into two categories, process control and end control. Process control is aimed at VOCs production process, VOCs from the principle of reducing the production of VOCs, generally through process improvement, technological innovation and leakage control to achieve. The end control is aimed at the chemical characteristics of VOCs, focusing on the VOCs emission control, the use of combustion, decomposition and other methods to control VOCs emissions.

Adsorption technology

Principle: The use of adsorbents and pollutants (VOCs) physical combination or chemical reaction and the removal of contaminated components.

Applies to: the low concentration of VOCs purification.

Advantages: removal of high efficiency, easy automation and control.

Disadvantages: not suitable for high concentration, high temperature organic waste gas, and the adsorbent material needs to be replaced regularly.

Absorption technology

Principle: The VOCs are removed from the exhaust gas by contact with the exhaust gas and the scrubbing liquid, and then the chemical agents are used to neutralize VOCs, oxidize or destroy other chemical reactions.

Applies to: High water-soluble VOCs, not suitable for low concentrations of gases.

Advantages: The technology is mature, can remove gaseous and particulate matter, low investment costs, small footprint, high mass transfer efficiency, efficient removal of acid gases.

Disadvantages: follow-up wastewater treatment problems, high concentrations of particulate matter, can lead to blockage of the tower, high maintenance costs, may take white smoke.

Condensation technology

Principle: Condensation The exhaust gas is cooled to a temperature below the dew point of the VOCs so that it is condensed into a liquid and recovered.

Scope of application: Used for the treatment of VOCs with high concentration and single component recovery value. Higher processing costs, it is usually VOCs concentration ≥ 5000ppm, had just applied condensation treatment, the efficiency of between 50 ~ 85%; concentration ≥ 1% above, then the recovery efficiency of up to 90%. Condensation is often accompanied by other control techniques such as incineration, adsorption, washing and the like as pre-treatment steps.

Membrane separation technology

Principle: The use of synthetic membrane separation of VOCs material.

Scope: High concentration of VOCs, recovery efficiency higher than 97%.

Advantages: recyclable components; high efficiency; integration of the remaining technologies.

Disadvantages: higher cost; can cause membrane fouling; poor membrane stability; low flux.

Plasma technology

Principle: The plasma field is rich in a large number of active species, such as ions, electrons, excited atoms, molecules and free radicals; active species will contaminate molecules dissociate small molecules.

Scope: low concentrations of VOCs, indoor air purification.

Features: Removal of VOCs at low temperature; suitable for VOCs with low concentration and high volume of air; high processing efficiency and low energy consumption; purifying and fresh air.

Photocatalysis technology

Principle: The photocatalyst nanoparticles are stimulated to produce electron-hole pairs under the irradiation of light of a certain wavelength. The water adsorbed on the surface of the hole-decomposing catalyst generates hydroxyl radicals. Electrons reduce the oxygen around them to active ion oxygen, Strong redox ability, the photocatalyst surface of various pollutants destroyed.

Advantages: mild conditions, room temperature and pressure; simple equipment, easy maintenance; reduce or even no secondary pollution.(Source: Valley Teng environmental network)

Tianjin Sino International Trading Co., Ltd. is a comprehensive environmental pollution control high-tech enterprise integrating research and development, production, installation and after-sales service of exhaust gas treatment and dust control engineering equipment. Our products are suitable for environmental management in various industries such as furniture industry, wood products industry, shoemaking industry, chemical industry, feed mill, and electronics industry. We can design environment-friendly solutions to customer satisfaction according to different needs of customers.