| OCR Text |
Show 3. The Reburning System Figure 1 displays the conceptual diagram of reburning system. Under this system, natural gas is injected into the furnace near the primary combustion chamber exit, forming reducing atmosphere. NOx and its intermediary products are removed here, and the secondary combustion air completely burns the CO generated in the furnace with the help of unburnt reburning gas. It helps reduce CO as well. Ninety percent of the NOx generated by refuse incinerators is Fuel NO, and the primary combustion chamber contains not only NO but the intermediary products such as HCN, NCO and NHi as a mixture. In a ddition to the reduction of NO, it is important to control the generation of NO by removing these intermediary products for the total deNOx in the furnace. In the reburning system, injection of secondary combustion air does not generate new NO since it removes the secondary products in addition to reducing NOx. This improves the removal efficiency. Also, the natural gas burns easily by the presence of overfire combustion air, completely burning the CO contained in the flue gas. MSW Burnout Zone Combustion Zone Figure 1 NOx Reduction Process in Reburning 3 |
