Effects of high-voltage power sources on fine particle collection efficiency with an industrial electrostatic precipitator

This paper presents industrial investigations on fine particle grade collection efficiency of an industrial electrostatic precipitator (ESP). Experiments are performed with a hybrid ESP and fabric filter (FF). Gas flow rates, mass inlet concentration, gaseous temperature and the ESP plate–plate distance are 20,000–40,000 Nm3/h, 15 g/Nm3, 110 °C, and 400 mm, respectively. The ESP specific collection area ranges from 10 to 20 m2/m3/s. Both single-phase and three-phase transformer-rectifiers (TRs) are used for energizing the ESP. When changing the single-phase TR to the three-phase TR, the maximum average secondary voltage is increased from 55 kV to 71 kV and average corona current rises from 31 mA to 62 mA without spark breakdown. As a result, both fine particle grade collection efficiency η(r) and their migration velocities are significantly increased. With the single-phase TR, the velocity is around 17 cm/s for all particles. With three-phase TR, its maximum value is about 35 cm/s. For particles within 0.03–0.1 μm and 0.1–2.5 μm in diameter, the efficiencies rise from about 85% to 95% and 92, respectively. For particles of around 2.5–8.0 μm, they rise from about 87% to about 98%. Moreover, experiments show that a revised Deutsch equation gives a good approximation via the average electric field Ea, the specific collection area S and two correction coefficients α and β, which depend on particle size.