Fly ash and sorbent particles agglomeration and removal in system of electrostatic agglomerator and electrostatic precipitator

The paper presents experimental studies on the effect of sodium bicarbonate and calcium hydroxide dry, low temperature sorbent injection on the concentration and size distributions of precipitated particles (fly ash and sorbent particles mixture), fractional collection efficiency, and particles morphology. The measurements were carried out on a lab-scale system comprising unipolar electrostatic agglomerator and electrostatic precipitator. In the experiments presented in this paper, the sorbent was injected upstream of electrostatic agglomerator. Results of SEM studies revealed the process of sorbent and fly ash particles agglomeration. The measurement of resistivity of fly ash and sorbent mixtures have shown that injected sorbent has a large effect on the particles resistivity, when the temperature of dust cake is increasing. In practical situations, too high resistivity can lead to back corona discharge generation, while too low causes the particles re-entrainment; both of these phenomena can reduce the dust collection efficiency of an electrostatic system.