某200MW四角切圆锅炉燃烧器改造降低NO_x数值模拟

针对国内某电厂200MW四角切圆锅炉NOx排放量较高,结渣严重的问题,利用CFD软件平台,采用数值模拟方法对其改造前后炉内燃烧过程进行研究。计算结果表明:由于附壁射流的作用,使得高温区集中在炉膛中部,有效地防止了锅炉结渣;改造后炉内有比常规燃烧方式锅炉更大的还原气氛区域,抑制了NOx的产生,使其排放降低34.6%。改造后的计算结果与试验相符的较好,所以此次数值模拟为锅炉设计、改造和运行提供理论依据。

Numerical Simulation of the Modification of Burners for a 200 MW Tangentially Fired Boiler to Reduce NOx Emissions

To address such problems as comparatively high NOx emissions and serious slagging in the 200 MW tangentially fired boiler of a power plant in China,a study has been conducted of the in-furnace combustion process before and after burner modification by using a CFD(computational fluid dynamics) software platform and numerical simulation method.The calculation results show that due to the effect of attached wall jet flow,high-temperature zones are concentrated in the central part of the furnace,effectively preventing boiler slagging.After modification,the furnace had a reducing atmosphere zone even greater than that of a boiler adopting conventional combustion modes,thus suppressing the generation of NOx emissions and reducing them by 34.6%.The calculation results after the modification correspond quite well with those of test ones.The numerical simulation can well provide a theoretical basis for the design,modification and operation of the boiler in question.