The principle of plasma removal of exhaust gas
The plasma is the fourth state after the solid, liquid, and gaseous states. When the applied voltage reaches the discharge voltage of the gas, the gas is broken down, producing a mixture including electrons, various ions, atoms, and radicals. Although the electron temperature is high during discharge, the temperature of heavy particles is very low and the entire system exhibits a low temperature state, so it is called a low-temperature plasma.
There are four types of plasma technology currently used, dielectric barrier discharge (dual medium, single medium), tip discharge (metal, fiber), plate discharge, microwave discharge, the actual application also has a combination of modes. Under the action of an external electric field, a large number of energetic electrons generated by the medium discharge bombard the pollutant molecules, causing them to be ionized, dissociated, and excited. Then they trigger a series of complicated physical and chemical reactions, turning the complex macromolecular pollutants into Simple small molecule safe substances, or make toxic and harmful substances into non-toxic harmless or low toxicity and low-damage substances, so that the pollutants can be degraded and removed. Since the average energy of the electrons generated after ionization is 10 eV, the chemical reaction that is difficult to achieve or is very slow under normal circumstances can be achieved by appropriately controlling the reaction conditions. As a high technology with extremely strong potential advantages in the field of environmental pollution treatment, the plasma has been highly concerned by the relevant disciplines at home and abroad. (Note: Low temperature plasma is normal temperature operation relative to high temperature plasma.)
Mechanism of Removal of Contaminants by Low Temperature Plasma
In the plasma chemical reaction process, the energy transfer of the chemical energy of plasma in the low-temperature plasma equipment during the reaction is roughly as follows:
(1) Electric field + electrons → high energy electrons
(2) High-energy electrons + molecules (or atoms) → (excited atoms, excited radicals, free radicals) Active groups
(3) Active groups + molecules (atoms) → products + heat
(4) Active group + active group → product + heat From the above process, it can be seen that the electrons of the low-temperature plasma equipment first obtain energy from the electric field and transfer the energy to molecules or atoms through excitation or ionization to obtain energy molecules. Or atoms are excited, and some of the molecules are ionized to become active groups; then these active groups and molecules or atoms, active groups and active groups collide with each other to generate stable products and heat. In addition, high-energy electrons can also be trapped by substances with strong electron affinity such as halogen and oxygen and become negative ions. Such negative ions have very good chemical activity and play an important role in chemical reactions.
Low-temperature plasma exhaust gas treatment equipment technology
Low-temperature plasma exhaust gas treatment equipment mainly uses the ions generated by the plasma generator to bombard contaminants, ionize, dissociate, and excite them. Then it initiates a series of complex physical and chemical reactions that turn complex macromolecular pollutants into simple ones. Molecular safety substances, or substances that convert toxic and hazardous substances into non-toxic, harmless or low-toxicity substances, so that the pollutants can be degraded and removed.
In recent years, various technologies have emerged in the world to deal with the pollution problems of industrial exhaust gases, such as ultrasonics, photocatalytic oxidation, biological methods, freezing methods, and incineration methods. Among them, low-temperature plasma is a kind of high-efficiency, low-energy-consumption, large-capacity and simple-to-operate new environmental protection technology to deal with toxic, hazardous, and hard-to-degrade substances. Low-temperature plasma equipment is a major scientific and technological achievement in recent years and has other methods unmatched. Absolute advantage.
Low-temperature plasma technology has a wide range of applications. The flow rate and concentration of gas are two very important factors for the application of gaseous pollutant treatment technologies. Biofiltration and combustion technologies can be applied to higher concentration ranges but are limited by the gas flow rate. The low-temperature plasma technology has a wide range of applications for the flow rate and concentration of gases. The application of low-temperature plasma equipment is widely understood. Plasma technology is simple. Adsorption method to consider the regular replacement of the adsorbent, desorption may also cause secondary pollution; combustion method requires a high operating temperature; biological method to strictly control the pH, temperature and humidity conditions to meet the growth of microorganisms. The low-temperature plasma technology is a good way to overcome the deficiencies of the above technologies, the reaction conditions for the normal temperature and pressure, the reactor structure is simple, low-temperature plasma equipment and can eliminate mixed pollutants (in some cases there is a synergy), will not produce Secondary pollution and so on. As far as economic feasibility is concerned, the system configuration of the low-temperature plasma reactor itself is compact, and in terms of operating costs, microscopically speaking, as the discharge process only increases the electron temperature while the ion temperature remains basically unchanged, the reaction system can be maintained at a low temperature. Low-temperature plasma equipment not only has a high energy utilization rate, but also has low equipment maintenance costs.
Low-temperature plasma technology has significant advantages in the treatment of gaseous pollutants. The basic principle is that under the acceleration of the electric field, high-energy electrons are generated. When the average energy of the electrons exceeds the chemical bond energy of the target chemical, the molecular bonds are broken to achieve the purpose of eliminating gaseous pollutants.
Vde Scissors,Vde/Gs Certificate Scissors Cutter,Vde 1000V Scissors Cutter,Custom Vde Scissors
Shanghai Countool In't Trading Co.,ltd , https://www.countool.com