ABSTRACT: High-con小可centration CaO particles and gas co紅志mpositions have a signi問算ficant influence on N生小Ox reduction by selective non-c著內atalytic reduction (SNCR)男鐘 in cement precalciners. The effect弟也 of gas composition 有上on NOx reduction by SNCR with NH₃ was 快低studied in a cement precalciner at短熱mosphere with and without CaO at 700都村-1100 °C. It was found that C著離aO significantly lowers NOx reduc風遠tion efficiency between 750 °C and 10鐘聽00 °C, which is attribu不樹ted to the catalytic船算 oxidation of NH₃ to NO. Although incr玩坐easing NH₃ concentration was照動 advantageous to NOx reduction冷員, the existence of CaO l多銀ed to the opposite resu熱人lt at 750-900 °C. Adding H₂O can supp線門ress the negative effect 長愛of CaO on NOx reduction. Decreasing O輛計₂ content from 10% to 1% shifts the te錯讀mperature range in which CaO has a si道也gnificant effect from地間 750-1000 °C to 800-1050 °C. CO風裡 has a variety of influences請個 on the CaO effect un白內der different experimental co能筆nditions. The influences of NH₃, H₂O, O花可₂, and CO on the effect of CaO can be為海 attributed to the impacts of the ga光電s compositions on gas-phas志化e NH₃ conversion, gas-soli內要d catalytic NH₃ oxid街火ation, or both processes. A proposed p行場athway for the effect of gas來空 compositions on NOx reduction in Ca南個O-containing SNCR process was deve線雜loped that well predicted the 熱月CaO-containing SNCR process.
