An experimental study of thermal de-NO_x using NH_3 as reductant in O_2/CO_2 atmosphere with the effect of SO_2and different additives was performed in a drop tube furnace.Results show that the optimum temperature window is 841-1184 ℃.and the optimum reaction temperature is about 900 ℃ with a de-NO,efficiency of 95.4%.A certain amount of SO_2 has an inhibiting effect on NO reduction.The effect of additives,including Na_2CO_3,C_2H_5OH and FeCl_3,on NO reduction by NH_3 is also explored.The addition of Na_2CO_3 and FeCl_3 is useful to widen the temperature window and shift the reaction to lower temperature for the efficiency is increased from 30.5%to 74.0%and 67.4%respectively at 800 ℃.Qualitatively,the modeling results using a detailed kinetic modeling mechanism represent well most of the process features.The effect of Na_2CO_3,C_2H_5OH and FeCl_3 addition can be reproduced well by the Na_2CO_3,C_2H_5OH and Fe(CO)_5 sub-mechanism respectively.The reaction mechanism analysis shows that the effects of these additives on NO reduction are achieved mainly by promoting the production of OH radicals at lower temperature.
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