Plasma is the material status after solid, gas and liquid. We can say that it is the fourth state of the material. It is composed of positive ions, negative ions, electrons and neutral ion. Because the system is equal to the total negative charge, so we called "plasma".
Plasma can be divided by the particle temperature. It is the equilibrium (electronic temperature = ion temperature) status and nonequilibrium (electronic temperature > ion temperature) status two kinds.
Nonequilibrium plasma electron temperature can be tens thousands degree. Ionic and neutral ions can be low to room temperature. The temperature system is still very low, so called "low temperature plasma". Usually, the plasma can be produced by gas discharge.
Low temperature plasma technology is developed in recent years. It is used for waste gas treatment. The principle of low temperature plasma processing waste gas are as following:
When the applied voltage reaches gas discharge voltage, breakdown the gas. It will produced electronics, all kinds of ions, atoms and free radicals, etc. Low temperature plasma degradation of pollutants. It is to use these high energy electron, free radicals to mix other reactive particles and pollutants in the exhaust. The pollutant molecules decomposition happens within a very short time. In order to achieve the purpose of the degradation of pollutants.
Low temperature plasma technology, the principle of pollutant is: under the action of applied electric field, a large number of high energy electron bombardment pollutant molecules produced by a dielectric discharge. To make ioniz ation, dissociation and excitation. And then raises a series of complicated physical and chemical reaction. It makes complicated molecules pollutants into simple small molecule and safe material, Also, it makes the poisonous and harmful substances into harmless non-toxic or low toxic less harmful substances. So that the degradation of pollutants removal.
Because of its ionization produced after electron average energy in ev 1 ~ 10 ev. To proper control of reaction conditions can be implemented generally difficult to achieve chemical reactions become very fast or slow.The energy transfer process as follows:
Electric field + high-energy electrons
High energy electron + molecules (or atoms) excited molecule gene activity
Active gene + molecules (or atoms) material + hot
Active gene activity + Active gene activity material + hot
To treat the printing waste gas, in the project, in the the low temperature plasma generator of dielectric barrier discharge (DBD), this exhaust gas factor of benzene ring was first open to pieces after high energy electron bombardment.
In tail gas of oxygen and moisture under the effect of high energy electron produces the following reaction
O2 ＋ e O＋ O3 + O2-
H2O + e HO＋ H
Exhaust gas factor solution from the fragments of the particles and oxygen and O + O3 + O2 - more complex chemical reaction, degradation such as CO2 and H2O.
Low temperature plasma technology, belongs to the dry processing, do not need any adsorbent, catalyst, and any other fuel combustion, only need to use 220 v or 380 v alternating current (ac), the oscillation booster device for high frequency pulse electric field, produce high-energy electrons, bombarding decomposition organic molecules in the exhaust gas, toxic gas molecules. Have a safe and reliable, simple operation, high efficiency, low operating cost, management advanced technology, etc.
Electric field is designed for exhaust particles moving slowly. Usually, within tenths of seconds, it can make enough charges on the exhaust particle charges. The particle in the electric field will be affected by electric field force (coulomb force). As a result, the soot particles are adsorbed to the anode. So purification rate is very high, and is particularly suited to capture size smaller and lighter in weight exhaust particles.