Experimental research of limestone effect on particulates and heavy metals emitted from coal combustion

Particle size distribution and effectiveness of sorbent injection for capture of heavy metals emission were investigated on a pilot scale 0.5 MW CFB test facility using mixed bituminous coal. Particulate matters concentration emitted from coal combustion increases from 2.98 to 5.04 g/Nm³ with the mean diameter increasing from 6.2 to 10.1 μm. Partitioning of the toxic heavy metals show that the concentrations of medium volatilily elements Cd and Pb increase with particle size decreasing and tend to enrich in submicron particles. Limestone injection in high temperature furnace helps to absorb heavy metals including Hg, Cd, Pb, Ni, and Cu in coal combustion.