| 摘要 |
<p>PURPOSE:To enable to obtain good denitrating effect even if coal easily generating NOx is used as a fuel by a method wherein a reducing zone, a main combustion zone and a recombustion zone are provided and an air ratio in respective zones is controlled to a predetermined ratio to generate a NOx reducing gas and, thereby, the generation of NOx is controlled. CONSTITUTION:A waste gas from a rotary kiln 11 is introduced into a reducing chamber 50 from a throttle part 23. Fine coal is supplied from a reducing burner 21 and hot air is supplied from a damper 28 so as to adjust an air ratio to 0.8-1.0 to generate CO gas and CO and NOx are subjected to contact reduction by using a cement stock material as a catalyst. Subsequently, the gas is raised into a main combustion chamber 60 and fine coal is supplied from a main burner 22 and hot air from a damper 29 so as to adjust an air ratio to 0.95-1.10 to combust almost all of a fuel while the generation of NOx is controlled. Next, recombusting air with an air ratio of 1.10-1.20 is introduced from a damper 30 to mix and combust the uncombusted gas at a throttle part 25. Further, the gas is reversed in a recombusting chamber to completely combust the same and, thereafter, the waste gas is sent to a cyclone of a cement baking system from a duct 18.</p> |
