Characterization of sintering dust collected in the various fields of the electrostatic precipitator
C. Lanzerstorfer, D. Steiner - Characterization of sintering dust collected in the various fields of the electrostatic precipitator - ENVIRONMENTAL TECHNOLOGY, Vol. 37, No. 12, 2016, pp. 1559-1567
Sinter plant off-gas is usually de-dusted by electrostatic precipitators. Compliance with the dust emission limits is often difficult because of the high specific resistivity of the emitted dust. Mechanical properties of the dust are also relevant for the electrostatic precipitator design. Dust samples from the four consecutive electrostatic precipitator fields were characterized in this study. Most measured parameters showed a considerable variation for the various dust samples. The particle size of the dust as well as its bulk density continuously decreased from the first field to the fourth field. The flowability of the dusts was generally bad and decreased from the first to the last field. In contrast, the wall friction angles with structural steel were quite constant at approximately 30°. The Fe content was lower in the dust from the last two fields while the concentration of K, Na, Cl- and SO42- was significantly higher. At the same time the particle density was lower. The maximum specific dust resistivity for the first field and second field dust were approximately 3·1011 Ω cm and no signs for the occurrence of back corona were detected. For the dusts from the last two fields the maximum value was approximately 2·1012 Ω cm. Back corona was observed in the temperature range from 120°C to 210°C. In this area the dust resistivity values were higher than 4.1011 Ω cm.