为了深度降低燃煤锅炉的NOx排放,需要对常规低NOx燃烧方式做进一步优化.对某采用低NOx燃烧技术的超超临界锅炉进行数值模拟,研究了“峰谷形燃烧”模式对炉内温度场、组分场、燃尽率和底渣量的影响,并与常规低NOx燃烧模式进行了比较.结果表明:在保持还原区及燃尽区过量空气系数不变的前提下,“峰谷形燃烧”模式可以较常规低NOx燃烧模式更进一步降低NOx排放,不会对整个炉膛内的燃烧、温度分布、炉底渣量和煤粉的燃尽产生明显的影响;某优化工况下,炉膛出口NOx含量可以较常规低NOx燃烧模式深度降低达12％.%In order to better reduce the NOx emission of coal-fired boilers,it is necessary to optimize the conventional low NOx combustion mode.The numerical simulation method is employed for an ultra-supercritical boiler with low NOx combustion technology.The impacts of the peak-valley combustion mode on the temperature,the concentration field,the burnout rate and the slag volume are studied and compared with the conventional low NOx combustion mode.The simulation and analysis results indicate that while keeping the excess air ratio of both the reduction zone and the burnout zone constant,the peak-valley combustion mode outperforms the conventional low-NOx combustion mode in low NOx combustion and has little effect on the combustion,the gas temperature,the bottom slag volume and the burnout rate.Under an optimal condition,the NOx concentration in furnace exit cross section is reduced by 12％.
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