Influence of Gas Composition on Corona Discharge Characteristics in the High Temperature / High Pressure Electrostatic Precipitator

The use of electrical corona discharge opens broad possibilities for effective development of electrostatic precipitators (ESPs). The object of the work is the study of the corona discharge in different gases at high temperature / high pressure (HT/HP) conditions. The studies are carried out in a HT/HP ionizer in the pure synthetic air, N2, He and He-synthetic air and He-N2 gas mixtures. Corona discharge characteristics are measured in electrode gaps of 10 mm and 15 mm. In the synthetic air, the corona onset voltage increases with increase of gas pressure. At constant applied voltage, the gas breakdowns take place at a lower pressure while for a higher pressure the corona discharge may not start yet. The stable corona discharge in dense He is observed at gas pressure up to P=10 MPa. For negative corona current is higher than for the positive corona. In the gas mixtures of ca. 50 Vol. % He in synthetic air or N2, the stable corona discharge is observed at higher pressures comparative to pure gases. In helium, corona onset and operation voltages increase linearly with increase of gas pressure. The current-voltage characteristics (CVCs) can be approximated by a polynomial equation rang 2.