Influence of operating temperature on performance of electrostatic precipitator for pulverized coal combustion boiler

摘要

Electrostatic precipitator (ESP) is a major dust collection device used in pulverized coal combustion boilers in Japan. Although the collection efficiency of ESP is over 99%, the performance of ESP is affected by dust properties, especially the electric resistivity of the dust. In Japan, many different kinds of coal are used in pulverized coal combustion boilers. The property of coal ash formed in pulverized coal combustion is different for different coals. It is very important to develop high performance ESPs for different kinds of coal ash. In general, the low temperature ESP operated at about 423 K has been used for a long time, but the electric resistivity of some kinds of coal ash is higher than suitable for the ESP in this temperature range. A high temperature ESP operated at 623 K was developed about 20 years ago and an advanced low temperature ESP operated at 373 K has been used recently for control of the electric resistivity of coal ash. In this paper, we report on the influence of operating temperature from 363 K to 623 K on performance of ESP for a pulverized coal combustion boiler. The influence of coal ash properties including electric resistivity, alkali metal concentration, and operating condition on collection efficiency of an ESP is estimated.