Characteristics of plasma
The high temperature of the plasma can provide a high enthalpy working medium, produce materials that cannot be obtained by conventional methods, and have the advantages of controllable atmosphere, relatively simple equipment, and significantly shortened process flow, so plasma technology has developed greatly. In 1879 W. Crooks pointed out that the ionized gas in the discharge tube was the fourth state of matter different from gas, liquid, and solid. In 1928, I. Langmuir named it plasma. The most common plasmas are luminescent gases such as arcs, neon and fluorescent lights, and lightning and aurora. With the development of science and technology, people have been able to artificially generate plasma by a variety of methods, thereby forming a widely used plasma technology. Generally speaking, plasmas with a temperature of about 108K are called high-temperature plasmas and are only used in controlled thermonuclear fusion experiments; plasmas with industrial application value are those whose temperature is between 2 × 103 ～ 5 × 104K and can last for several minutes. The low-temperature plasma of minutes or even tens of hours is mainly obtained by a gas discharge method and a combustion method. Gas discharge is divided into arc discharge, high-frequency induction discharge and low-pressure discharge. The plasma produced by the former two is called thermal plasma, which is mainly used as a high-temperature heat source; the plasma produced by the latter is called cold plasma, which has special physical properties that can be used industrially. However, due to the high-voltage discharge in the treatment of organic waste gas, it is necessary to prevent explosions that are easy to ignite.