The effect of gas temperature on dust resistivity and removal efficiency in an extra cold-side electrostatic precipitator

Abstract

The field tests of electrostatic precipitator (ESP) in a coal-fired power plant, including online tests of dust resistivity and 12-stage number concentrations by using electrical low-pressure impactor (ELPI), are carried out under the flue gas temperatures of both 130 and 90 °C. The temperature is adjusted by well controlling the operation conditions of a heat exchanger installed in front of ESP. The data of both number concentration and mass concentration indicate that the collection efficiencies of PM2.5 and PM10 are continuously increased with the decreasing gas temperature from 130 to 93 °C and eventually to 84 °C. The online tests of dust resistivity show a decrease from 6.09 × 1011 to 2.46 × 1011 and 1.60 × 1011Ω cm, corresponding to the temperatures of 130, 93, and 84 °C, respectively. The particle charging distributions under different temperatures testify the improvement of charging characteristic with lower temperature.