赤泥回转窑双旋流燃烧器掺燃甘蔗髓数值模拟

Numerical simulation study on mixed combustion of bagasse pith with double swirl burners in red mud rotary kiln

针对赤泥回转窑煤粉燃烧器在使用时导致的高煤耗问题,以寻求更节能环保的煤替代燃料,进行赤泥回转窑双旋流燃烧器掺燃甘蔗髓的数值模拟研究。应用Fluent软件,建立数值模型。考察在掺混15%(热耗替代率)的蔗髓做为部分烟煤替代燃料的条件下,对比内旋流风角度分别为20°、30°、40°时,回转窑内的速度场、温度场以及燃烧组分的分布情况。结果表明,在回转窑中掺混高挥发分蔗髓,可得到较理想的燃烧工况。随着内旋流风角度的增大,会影响蔗髓和烟煤粉的燃烧效率,促进燃料燃烧,减少CO的产生,同时导致NOx排放增加。在回转窑中,高挥发分蔗髓与低挥发分烟煤粉混燃,可产生协同效应。在一定范围内增大内旋流风角度,会促进蔗髓挥发分的释放,从而提高烟煤粉的燃烧效率。

Aiming at the problem of high coal consumption caused by the use of pulverized coal burner in red mud rotary kiln,in order to seek a more energy conservation and environmental coal substitutes,a numerical simulation study on mixing bagasse pith with double swirl burner in red mud rotary kiln was carried out.With the Fluent software,the mathematical model was established.Under the condition that bagasse pith mixed with 15%(heat consumption replacement rate)was used as a partial substitute fuel for pulverized bituminous coal,the distribution of velocity field,temperature field and combustion component in rotary kiln were investigated when the internal swirling wind angle was 20°,30°and 40°respectively.The results show that with the increase of internal swirl angle,the combustion efficiency of bagasse pith and pulverized bituminous coal was affected,fuel combustion was promoted,CO production was reduced,and NO x emission was increased.In the rotary kiln,the mixture of bagasse pith with high volatile content and pulverized bituminous coal with low volatile content can produce synergistic effect.Increasing the angle of internal swirling air within a certain range can promote the release of volatile matter from bagasse pith and improve the combustion efficiency of pulverized bituminous coal.