Investigation on SO 2 emission from 410t/h circulating fluidized bed boiler burning petroleum coke and coal

Effects of operation parameters including bed temperature, Ca/S molar ratio, excess air coefficient, fly ash recirculation rate and limestone microstructure on SO 2 emission were investigated on a 410t/h circulating fluidized bed (CFB) boiler burning petroleum coke and coal. Results show that for different fuels, SO 2 emission is correspondingly related to the sulfur content in it under the same operation conditions. With increasing bed temperature, SO 2 concentration in the flue gas reduces first and then increases. There is an optimal desulfurization temperature. For burning bituminous coal (BC) only or 70% BC + 30% petroleum coke (PC), the optimal desulfurization temperature is about 850 °C, while it is about 850–870 °C for burning 50% anthracite (AN) + 50% PC. SO 2 emission decreases with the increase in Ca/S ratio, excess air coefficient and fly ash recirculation rate. Microstructure of limestone has distinct effects on their SO 2 retention capacity, and bigger specific surface area and higher specific pore volume lead to stronger SO 2 capture activities. The optimal temperature, Ca/S ratio and excess air coefficient for different fuels are recommended for industrial application. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.