| 摘要 |
Cement clinker production apparatus having a precalcination stage connected upstream of a rotary kiln, in which precalcination stage a CO-containing reduction zone in the rotary kiln off-gas duct is employed for the purpose of reducing the pollutant NOx. In order to make certain that the quantitative ratio of O2 in the rotary kiln off-gas to fuel admitted by a deNOx burner, and thus control the effectiveness of NOx reduction, a pivoting throttle valve (33) is positioned in the precalcination stage to control the quantity of rotary kiln off-gas and thus the O2 content in the kiln off-gas. The throttle valve (33) is positioned in the rotary kiln off-gas duct (15) above the deNOx burner (19), above the raw meal inlet (13), and before the confluence of the tertiary air substream with the rotary kiln off gas. The throttle valve (33) is pivotable about an articulation (34) at the bottom side of the valve so that the flow of the rotary kiln offgas remains laminar, thus enhancing the reaction length of the CO-containing reduction zone (23).
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