Some Consideration on Enlarging Phenomena of Electrodes of an Electrostatic Precipitator Due to the Dust Adhesion

Abstract

Electrodes of an electrostatic precipitater are commonly hammered in order to prevent the dust from adhering to them. All of the dust, however, cannot be completely taken away, and the electrodes of this instrument, with the progress of operation, enlarge by the dust adhesion, bringing about the lowering of collecting efficiency.This report has elucidated the relation of the operation term to the amount of enlargement of electrodes and that of the collecting efficiency to the latter, by using an apparatus manufactured for a trial, which can (automatically and sequentially) take photographs of the appearance of the electrodes of the electric precipitator at an oil-coal mixed firing boiler in operation, and also has described some investigation into enlarging phenomenon of electrodes caused bv the dust adhesion, based on measurement of acceleration distribution during the hammering.As a result, the relation between the enlarging amount of a discharge electrode W and the operation term Z is shown as W=A(1-e-kz), and the greater the mixing rate of heavy oil, the smaller the maximum enlarging amount of A. The strength of the dust adhesion to electrodes is far larger than that of the adhesion due to the static charge (280N/m2); it is presumed that the maximum amount reaches 3500N/m2 at a discharge electrode and 15, 000N/m2 at a collecting electrode, respectively.This seems due to the fact that owing to the condensation of moisture and sulfuric acid between particles of dust, or dust and electrodes, the particles and the electrode surfaces adhered are dissolved, and subsequently, the solidification or the crystallization of these dissolved materials results in the cross-link phenomena.