A pilot scale study of the rapping reentrainment and fouling in electrostatic precipitation



This article describes a number of tests that have been carried out using a pilot electrostatic precipitator (ESP) which operates with flue gases from a coal power plant. The purpose of these tests was to show the influence of the characteristics of the ash (resistivity) and the main design variables of an ESP (type of discharge electrode and collecting plate spacing) on the fouling of plates and discharge electrodes and the reentrainment of dust. Two types of coal, with high and low resistivity ashes, respectively, three types of discharge electrodes, and three typical collecting plate spacings were used in the tests. In fouling tests, the dust emission growth rate during periods with no rapping, the maximum permissible rapping interval, and the recuperation rate of the dust emission level after rapping were characterized. The maximum permissible rapping interval was defined as the time in which no alteration is observed in the operational variables of the ESP. In rapping tests, the relative increase of the dust emission level due to reentrainment was also characterized. The results of these tests have made possible to identify, for each of the tested coals, the ESP configurations (plate spacing and type of electrode) less sensitive to the formation of a permanent layer of ash and to the particle reentrainment due to rapping. © 2014 American Institute of Chemical Engineers Environ Prog, 34: 7–14, 2015