Effects of Sorbent Injection for Sulfur Dioxide Removal on Particulate Control Systems for Coal-Fired Boilers

摘要

The report describes studies undertaken to quantify the effects of dry SO2 sorbent injection on electrostatic precipitator (ESP) operation with a coal-burning utility boiler. The specific operation of interest was EPA's limestone injection, multistage burners (LIMB) process. The combination of spent sorbent and fly ash has a higher resistivity, a higher mass concentration, and a finer particle-size distribution than the ash alone; all of these factors diminish the effectiveness of ESP. Also investigated was chemical conditioning to reduce the resistivity problem, the only one of three concerns stemming from sorbent injection that can be readily mitigated. Other topics studied were: the recycle, disposal, and utilization of waste-ash/sorbent mixtures; the selection and modification of sorbents to improve SO2 capture in the furnace; and the reactivation of spent sorbent by humidification to achieve supplemental post-furnace capture of SO2.