1000MW超超临界锅炉燃烧调整的试验研究

Test Study on Combustion Adjustment for 1 000 MW Ultra Supercritical Boilers

对某电厂1 000MW燃煤锅炉进行了燃烧优化调整试验,分析了一次风配风均匀性、煤粉细度、燃烧器配风、运行中氧的体积分数以及燃尽风率对锅炉效率的影响.结果表明:对同层燃烧器外二次风采用两端和中间开度大的配风方式可以改善由于大风箱两端进风引起的沿炉膛宽度方向氧气的体积分数偏差.随着炉内氧气的体积分数增加,锅炉的热效率先提高后降低.当氧气的体积分数在3.0%左右时,锅炉热效率达到最高.随着燃尽风率的逐渐降低,锅炉热效率和NOx排放质量浓度逐渐提高.综合考虑锅炉效率、NOx排放质量浓度以及屏式过热器管壁金属温度,在额定负荷下,燃尽风率以保持在25%左右为宜,此时锅炉热效率为93.9%,NOx排放质量浓度为306.1mg/m3.

Experiments on combustion optimization and adjustment of a 1 000 MW power boiler were carried out, so as to analyze the influence of following factors on the boiler efficiency, such as the primary air distribution, fineness of pulverized coal, air distribution of burner, oxygen volumetric fraction and overfire air rate, etc. Results show that for the same layer of burners, the deviation of oxygen volumetric fraction distribution along breadth of furnace caused by wind inlet through both ends of big bellows can be improved by increasing the opening of distribution plates at both ends and middle positions for external secondary air. With the rise of oxygen volumetric fraction, the boiler heat efficiency increases first and reduces later on, which reaches the highest at an oxygen volumetric fraction of 3.0 %. With the reduction of over-fire air rate, both the boiler heat efficiency and mass concentration of NOx emission rise gradually. Comprehensively considering the boiler efficiency, NOx emission and metal temperature of platen superheater tubes, it is recommended that the over-fire air rate be kept at about 25% at rated load, when the boiler heat efficiency may reach 93.9 %, with a mass concentration of NOx emission at 306. 1 mg/m^3.