Effect of dry sorbent injection at different stages of industrial hybrid electrostatic filter on particle penetration and sulfur dioxide removal

Abstract

This study investigates the influence of in-duct dry sorbent injection at different stages of an industrial hybrid electrostatic filter on particle penetration and sulfur dioxide removal. Installed downstream of a 220 MW coal-fired power boiler, the hybrid system includes a single-field electrostatic precipitator, kinematic unipolar electrostatic agglomerator, and bag filter. Three sets of in-duct dry sorbent injection nozzles are located at the system's inlet, upstream of the electrostatic agglomerator, and upstream of the bag filter. Dry sorbent injection of sodium bicarbonate resulted in SO2 removal efficiency >83% with outlet SO2 concentration < <400 mg/m3. Results showed that the hybrid system exhibits PM2.5 mass collection efficiency of >99.9%. Sorbent injection at different stages influences the particle penetration and agglomeration of the sorbent and fly ash particles. The optimal results, regarding the SO2 removal, were obtained for injection of dry sorbent downstream of electrostatic agglomerator.