Simultaneous reduction of SO2 and NOx in an entrained-flow reactor

Simultaneous SO2 and NOx reduction in flue gas by the dry furnace sorbent injection process was simulated with an entrained-flow reactor. Several ammonium salts as well as urea were tested. Urea was found to give the highest NOx removal efficiency. By using urea-limestone sorbent, >90% SO2 removal and >80% NOx removal were obtained at Ca/S and N/NOx ratios both equal to 2. The DeNO(x) process is more temperature-sensitive than the DeSO(2) process, and 900 degrees C can be chosen as the overall optimum temperature. The N2O formed was <10 ppmv at 2 s residence time. A reductive path from NO2 or NO to N-2 is proposed to explain the experimental results.