Slagging in PC boilers and developing mitigation strategies

Large reductions in furnace exit gas temperature when a group of sootblowers is activated correspond to an effective surface cleaning. It also means that the deposition rate is very high on the surface that is covered by particular sootblowers. If a sootblower group is activated and there is a negligible impact on the furnace exit gas temperature this means either the surface is already clean or the deposit on the surface cannot be removed by sootblowing. The latter is a serious concern that may result in load reductions or forced unit outages. As can be seen from the following figure, the impact of each sootblower group on the FEGT varies from almost negligible to as high as 120 °F. The sootblower subgroups 4 and 6 did not have any impact on the FEGT while the subgroups 1, 2, 3, and 5 had quite large reduction FEGT.