Capturing Fine Particles Using Magnetical Enhancement Corona Pre-Charger In The Front Of An Electrostatic Enhancement Filter

In this paper, the experimental researches on the discharge characteristics of themagnetical enhancement corona discharges were carried out, and the discharge mechanismwas theoretically analyzed. The magnetical enhancement functions between positive andnegative corona discharges were experimentally compared. The magnetical enhancementeffects in different inter-electrode regions were researched. The researches demonstrated thatmagnet field can efficiently increase the concentrations of ions and free electrons in annegative corona discharges. The dominant mechanism of magnet enhancement in coronadischarges is that the Larmor movements of free electrons enhance the non-thermal plasma inionization region near discharge electrode. A reasonable configuration for magnetenhancement can be formed by permanent magnets with a local strong magnet field near thedischarge electrode. A magnetical enhancement pre-charger with negative corona dischargeswas assembled in the front of an electrostatic enhancement filter. The influence of thepre-charger on the filter was measured and compared with that of the traditional coronapre-charger. The free electron charging mechanism of the magnetical enhancement coronapre-charger was preliminarily analyzed. The new pre-charging technology is promising for thecapturing fine particles in electrostatic enhancement filters or electrostatic precipitators. Thecharacteristics of the magnetical enhancement corona discharges and their functions forcharging particles are introduced. The experimental results demonstrated that the magnet fieldcould obviously increase the discharge current and enhance the particle density in coronadischarges. The deflection of free electrons between the discharge and collection electrodeswas measured. Therefore we can deduce that the concentration of both free electrons and ionsare increased in the magnet enhancement corona discharges. Comparing with the uniformmagnet field, the non-uniform magnet field formed by the permanent magnet nearby thedischarge electrodes can more effectively intensify corona discharges. Some researchers onthe magnetical enhancement corona discharges and the function for changing particles aredone. In our researches, free electrons were deflected in a magnetic field and traveling lengthsof the free electrons were greatly increased. The density of both the electrons and negativeions were increased. Moreover, a simple DC HV power supply was employed and thecharging time on particles was continued. We developed an aerosol charger of the magnetenhancement corona discharges with permanent magnet. The experiments that the chargingcurrent of magnet enhancement corona discharge is greater than the traditional one. Butenhancement of charging currents not always induces the increase of the efficiency forcharging particles. In short pulse corona discharges, the non-thermal plasma region alwayspropagate in a direction across the air stream and dipolar charging of particles occurs.Therefore, the charging efficiency is greatly reduced under the intensive short pulse coronadischarges. An negative corona magnetical enhancement pre-charger was assembled in thefront of an electrostatic enhancement filter. The experiment could confirm the increase ofcharging efficiency for particles in the pre-charger, which can produce effective improvementof the filtration efficiency in an electrostatic enhancement filter. Therefore, the magneticalenhancement corona discharges could serve as an advanced charging technique and would bepromising in the applications for electrostatic enhancement filters or electrostaticprecipitators.