Waste gas treatment equipment mainly refers to an environmental protection equipment that uses different technologies to protect the environment and purify the air by recycling or removing and reducing harmful components in waste gas.
Classification:
Absorption equipment
Absorption method is to absorb VOCs with low volatility or non-volatile solvent, and then separate VOCs by using the difference of physical properties between VOCs and absorbent.
The gas containing VOCs enters the tower from the bottom of the absorption tower, and contacts with the absorbent from the top of the tower in countercurrent during the rising process, and the purified gas is discharged from the top of the tower. The absorbent that absorbs VOCs enters the top of the stripper through a heat exchanger and desorbs at a temperature higher than the absorption temperature or a pressure lower than the absorption pressure. The desorbed absorbent is condensed by the solvent condenser and then returned to the absorption tower. The desorbed volatile organic compound gas leaves the stripper as pure volatile organic compound gas after passing through the condenser and gas-liquid separator, and is recovered. This process is suitable for gas purification with high VOCs concentration and low temperature, and other conditions need corresponding process adjustment.
Adsorption equipment
When a fluid mixture is treated with a porous solid substance, a certain component or some components in the fluid can be adsorbed on the surface and enriched on the surface, which is called adsorption. When waste gas is treated by adsorption, the object of adsorption is gaseous pollutants, gas-solid adsorption. The adsorbed gas component is called adsorbate, and the porous solid material is called adsorbent.
After the adsorbate is adsorbed on the solid surface, a part of the adsorbed adsorbate can be separated from the surface of the adsorbate, and the adsorbate is adsorbed. However, after a period of adsorption, due to the concentration of adsorbate on the surface, its adsorption capacity is obviously reduced, which meets the requirements of adsorption and purification. At this time, some measures should be taken to desorb the adsorbate adsorbed on the adsorbent to enhance its adsorption capacity. This process is called adsorbent regeneration. Therefore, in the actual adsorption engineering, removing pollutants from waste gas and recovering useful components in waste gas is a cyclic process of adsorption-regeneration and repeated adsorption.
purifying equipment
Combustion method is very effective in treating high concentration Voc and malodorous compounds. Its principle is to burn these impurities with excessive air, and most of them generate carbon dioxide and water vapor, which can be discharged into the atmosphere. However, when dealing with chlorine-containing and sulfur-containing organic compounds, HCl or SO2 in combustion products needs further treatment.
treatment facility
Plasma is ionized gas, and its English name is plasma. It was named by American scientist Muir when he studied the discharge phenomenon in mercury vapor at low pressure in 1927. Plasma consists of a large number of protons, neutral atoms, excited atoms, photons and free radicals, but the charges of electrons and positive ions must be electrically neutral, which is the meaning of "plasma". Plasma is different from solids, liquids and gases in many ways, so some people call it the fourth state of matter. According to the state, temperature and ion density, plasma can usually be divided into high temperature plasma and low temperature plasma (steamed stuffed bun and cold plasma). Among them, the ionization degree of high-temperature plasma is close to 1, all kinds of particles are in thermodynamic equilibrium, and the temperature is almost the same. It is mainly used for the study of controlled thermonuclear reactions. However, the low-temperature plasma is in a non-equilibrium state, and the temperatures of various particles are different. Among them, the electron temperature (Te)≥ ion temperature (Ti) can reach more than 104K, while the temperature of ions and neutral particles can be as low as 300 ~ 500 K ... Generally speaking, gas electron dischargers belong to low-temperature plasma.
By 20 13, the mechanism of low temperature plasma is considered to be the result of inelastic collision of particles. Low-temperature plasma is rich in electrons, ions, free radicals and excited molecules, in which high-energy electrons collide with gas molecules (atoms) to convert energy into internal energy of ground-state molecules (atoms), and a series of straws such as excitation, dissociation and ionization are activated. On the one hand, gas molecular bonds are opened, and some single molecules and solid particles are generated; Another force produces free radicals, such as. Oh, H2O2. And O3 with strong oxidizing property. In this process, high-energy electrons play a decisive role, and the thermal movement of ions has only side effects. At atmospheric pressure, the electron temperature in the highly unbalanced plasma generated by gas discharge is much higher than the gas temperature (room temperature is about 100℃). Various types of chemical reactions may occur in non-equilibrium plasma, which are mainly determined by the average energy of electrons, electron density, gas temperature, molecular concentration of harmful gases and gas composition ≥ This provides conditions for some reactions that require great activation energy, such as removing refractory pollutants in the atmosphere, and also treating volatile organic pollutants and sulfur-containing pollutants with low concentration, high flow rate and large air volume.
The common method of generating plasma is gas discharge. The so-called gas discharge is to ionize an electron from a gas atom or molecule through some mechanism, and the gas medium formed is called ionized gas. If the ionized gas is generated by an external electric field and forms a conductive current, this phenomenon is called gas discharge. According to the mechanism of discharge, the nature of pressure J source and the geometry of electrode, gas discharge plasma is mainly divided into the following forms: ① glow discharge; ③ Dielectric barrier discharge; ④ RF discharge; ⑤ Microwave discharge. No matter what kind of plasma is generated, high voltage discharge is needed. It is easy to cause fire and danger. Because the treatment of gaseous pollutants is generally required to be carried out under normal pressure.
5. Photocatalytic and biological purification equipment
Photocatalysis is a deep reaction technology at room temperature. Photocatalytic oxidation can completely oxidize organic pollutants in water, air and soil into non-toxic and harmless products at room temperature, while traditional high-temperature incineration technology needs extremely high temperature to destroy pollutants, even if the conventional catalytic oxidation method is used, it needs hundreds of degrees of high temperature.
Theoretically, as long as the light energy absorbed by the semiconductor is not less than its band gap energy, it is enough to stimulate the generation of electrons and holes, and the semiconductor may be used as a photocatalyst. Common single compound photocatalysts are mostly metal oxides or sulfides, such as Ti0, Zn0, ZnS, CdS and PbS. These catalysts have outstanding advantages for specific reactions, and can be selected according to needs in specific research. For example, the band gap energy of CdS semiconductor is small, which has a good matching performance with the near ultraviolet band in the solar spectrum, and can make good use of natural light energy, but it is prone to photocorrosion and has a limited service life. Relatively speaking, titanium dioxide has good comprehensive properties and is the most widely used and studied single composite photocatalyst.
Therefore, we need to know the specific price and determine the type of equipment. If you want to know more about waste gas treatment equipment, you can consult Guangzhou Zhongchuang Environmental Protection Technology Co., Ltd.