Influence factors and element release properties during NO reduction through biomass advanced reburning

NO reduction through advanced reburning (AR) with biomass including rice husk (RH), phoenix tree leaves (PTL) and saw dust (SD) was tested in an entrained flow reactor (EFR). The effects of reburning fuel species, reaction temperature in the reburning-zone (t₂), the location of ammonia injection, water vapor and additives on the NO reduction were investigated. Furthermore, the migration of chloride and potassium elements during biomass advanced reburning was examined. The results indicate that the NO removal efficiency via biomass advanced reburning shows a tendency of increase first and decrease later with increasing the reaction temperature in the reburning-zone from 850 ℃ to 1 150 ℃. The same tendency is also found as SR₂ increases from 0.5 to 1.0. The location of ammonia injection has a certain influence on the NO reduction with rice husk when the residence time is in the range of 0.4~1.0 s. The water vapor (0~15%) in the flue gas not only improves the NO removal efficiency, but also broadens the window temperature of DeNO_x, and the best NO removal efficiency can be obtained when the water vapor is about 4%. Additives (Fe₂O₃, KCl, NaCl and CaO) have a better promoting effects on the NO reduction through advanced reburning with rice husk, in which Fe₂O₃ shows the most significant effect on the NO reduction. The release of chlorine and potassium during advanced reburning with rice husk can reach more than 95.0% and 59.8%, respectively.