Experimental Studies On The Dust Removing Device Using Low Pressure Glow Discharge Plasmas

Plasma dust removal technology has been widely used in industry,such as power plants,chemical plant exhaust treatment.But under low-pressure environment,with decreasing in the environment pressure and particle density,the species mean free free path increases.This makes the particle charging become more and more difficult.On the other hand,the calculated breakdown voltages at low pressures based on the Paschen curve may be as high as tens of thousands of volts,or even higher.Thus,it is very difficult to produce large volume and uniform discharges.Therefore,the electrostatic dedusting technique does not work under very low pressure levles.In this thesis,a twostage electrostatic dedusting device based on low pressure radio-frequency(RF)glow discharges is designed with the background of low pressure gas purification.Firstly,the two parts of the dust removal device are designed.The first part is for the production of the RF glow discharges using argon as the plasma working gas and with a needle-plate electrode configuration.Because there is a high enough concentration of free electrons in the plasma region,it is beneficial to realize chargeing of small particles under low pressures.The second part is the traditional electrostatic collection region.The charged particles flow into the electrostatic collection region with gas flowing,and deposite on the collection plate under the externally applied electric field.Secondly,the discharge characteristics of low pressure RF glow discharge plasmas are studied experimentally.The electron density and temperature of the argon RF glow discharges are derived based on the optical emission spetra in the discharge region.Furthermore,the influences of the electrode gap spacing,single-and multi-needle-plate electron configurations on the discharge characterisitcs are investigated.Finally,the dimethyl silicone oil is used to simulate the pollutant particles under low pressures.The experimental results show that the purification efficiency of the designed two-stage dedusting device can reach up to 85%.Figure 54;Table 7;Reference 63...