The emission characteristics and co-removal through air pollution control devices of sulfurous pollutant were conducted at three 410 t·h-1 circulating fluidized bed boilers equipped with in-situ desulfurization + electrostatic precipitator (ESP)/fabric filter (FF) + wet flue gas desulfurization (WFGD). The US EPA Method 8 was used for the sampling of various forms of sulfurous pollutant in flue gas. Concurrent with flue gas sampling

the feed fuel

limestone

bottom ash

fly ash

gypsum and wastewater were sampled. The results showed that particulate-bound sulfur and SO2 are the dominant species in the flue gas at the outlet of boilers

accounting for 48.94%-55.05% and 44.14%-49.07%

respectively. The removal efficiency of particulate-bound sulfur by ESP or FF is more than 95%. About 62.66%-67.82% of SO3/sulfuric acid mist and 53.06%-60.89% of particulate-bound sulfur in flue gas was removed by WFGD

respectively. The majority of sulfur in fuel was migrated into fly ash + bottom ash and gypsum + wastewater

accounting for 56.79%-70.12% and 29.25%-41.70%

respectively. Only 0.63%-1.51% of total output sulfur was emitted into atmosphere.