Influence of dioxin reduction on chemical composition of sintering exhaust gas with adding urea

With the addition of urea as an inhibitor,four groups of reducing dioxin emission experiments in sintering pot were conducted.The results show that,adding 0.05%,0.1% and 0.5%(mass fraction) urea,the emission concentrations of dioxin are 0.287,0.258 and 0.217 ng-TEQ/m3,respectively,The dioxin emission rates drop substantially compared to 0.777 ng-TEQ/m3 free of urea.With an increase of the urea content,the concentration of SO2 emission reduces sharply.(NH4)2SO4,formed by the reaction of SO2 and NH3,goes into the dust and part of NH3 is released before reaction with the emission of exhaust gas.The NOx emission presents an increasing trend because the reaction of NH3 and O2 at high temperature produces NOx.Based on the consideration of factors such as the effect of reducing dioxin emission,and the chemical composition of exhaust gas,0.05% is the optimum adding content of urea.

With the addition of urea as an inhibitor, four groups of reducing dioxin emission experiments in sintering pot were conducted. The results show that, adding 0.05%, 0.1% and 0.5% （mass fraction） urea, the emission concentrations of dioxin are 0.287 0.258 and 0.217 ng-TEQ/m3, respectively. The dioxin emission rates drop substantially compared to 0.777 ng-TEQ/m3 flee of urea. With an increase of the urea content, the concentration of SO2 emission reduces sharply. （NH4）2SO4, formed by the reaction of SO2 and NH3, goes into the dust and part of NH3 is released before reaction with the emission of exhaust gas. The NO~ emission presents an increasing trend because the reaction of NH3 and 02 at high temperature produces NOx. Based on the consideration of factors such as the effect of reducing dioxin emission, and the chemical composition of exhaust gas, 0.05% is the optimum adding content of urea.