Determining Optimal Operation Parameters for Reducing PCDD/F Emissions (I-TEQ values) from the Iron Ore Sintering Process by Using the Taguchi Experimental Design

摘要

This study is the first one using the Taguchi experimental design to identify the optimal operating condition for reducing polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/ Fs) formations during the iron ore sintering process. Four operating parameters, including the water content (We; range = 6.0-7.0 wt %), suction pressure (Ps; range = 1000-1400 mmH_2O), bed height (Hb; range = 500-600 mm), and type of hearth layer (including sinter, hematite, and limonite), were selected for conducting experiments in a pilot scale sinter pot to simulate various sintering operating conditions of a real-scale sinter plant. We found that the resultant optimal combination (Wc = 6.5 wt%, Hb = 500 mm, Ps = 1000 mmH_2O, and hearth layer = hematite) could decrease the emission factor of total PCDD/Fs (total EF_(PCDD/Fs)) up to 62.8% by reference to the current operating condition of the real-scale sinter plant (We = 6.5 wt %, Hb = 550 mm, Ps = 1200 mmH)2O, and hearth layer = sinter). Through the ANOVA analysis, we found that We was the most significant parameter in determining total EFpcdd/ fs (accounting for 74.7% of the total contribution of the four selected parameters). The resultant optimal combination could also enhance slightly in both sinter productivity and sinter strength (30.3 t/m~2/day and 72.4%, respectively) by reference to those obtained from the reference operating condition (29.9 t/m (2)/day and 72.2%, respectively). The above results further ensure the applicability of the obtained optimal combination for the real-scale sinter production without interfering its sinter productivity and sinter strength.