ABSTRACT
The electric resistance of a powder bed is one of the most important properties, especially in relation to electrostatic precipitation. If the specifi c resistance r
d of particles is lower than 10 2 m, the particles will immediately be neutralized on the dust collecting electrode. Further, they are oppositely charged by the electrode and reentrained by gas fl ow in the presence of electrostatic repulsion between the particles and the collecting electrode. On the other hand, if the specifi c resistance is higher than 10 9 m, back discharge from the collecting electrode will occur, resulting in a decrease in the precipitation effi ciency. 1 The specifi c resistance of highly resistive powder is strongly dependent on the ambient temperature and moisture. It takes a maximum at some temperature (100 to 200°C) and decreases with increasing absolute humidity. 2 It also depends on the chemical composition of particles.
