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采用Fluent 6.3软件,对1台400 t/h四角切圆燃煤锅炉内的煤粉浓淡、空气分级及两者联用等3种燃烧过程进行了数值模拟,分析了煤粉浓淡比对炉内NOx和煤烟生成的影响.结果表明:与原始工况相比,仅采用煤粉浓淡燃烧时,NOx的生成量降低12.6%,但煤烟生成量会增加.当联合使用煤粉浓淡与空气分级燃烧时,随着煤粉浓淡比的增大,NOx生成量逐渐减少,当浓淡比值大于5时,NOx生成量的降低幅度趋于平缓;煤烟生成量随着煤粉浓淡比的增大先减少后增加,当煤粉浓淡比为3~5时,煤烟生成量最少.在两者联用条件下,NOx生成量的降幅可达27.6%,同时煤烟生成量也有所下降,这对锅炉的优化改造有一定的指导作用.
The Fluent 6.3 software was used to simulate the combustion processes of pulverized coal concentration, air fraction and their combination in a 400 t / h tangentially fired coal fired boiler. NOx and soot formation.The results show that when only pulverized coal combustion is used, the formation of NOx reduces by 12.6%, but the soot production will increase.When the combination of pulverized coal concentration with air In the staged combustion, as the pulverized coal concentration ratio increases, the amount of NOx produced decreases gradually. When the ratio of rich to light is greater than 5, the decrease of NOx production tends to be gentle. As the soot build-up ratio increases, The first reduction and then increase, when the pulverized coal concentration ratio of 3 to 5, the soot generated the least .In the combination of the two conditions, NOx production decline of up to 27.6%, while soot production also declined, which The optimization of the boiler has a guiding role.