300 MW机组锅炉内煤粉与有机固废热解气混燃特性的模拟研究

Simulation study on co-combustion characteristics of pulverized coal and pyrolysis gas of organic solid waste in 300 MW boiler

为研究煤粉与有机固废热解气的混燃特性,基于某330 MW机组四角切圆锅炉,搭建了煤粉掺烧热解气模型,考察了掺混比为10%,20%和30%的热解气对炉膛速度场、温度场及燃烧产物排放等的影响规律。结果表明,掺混比为30%以内的热解气与煤粉混燃对炉膛内整体速度场没有显著扰动,流场分布良好;掺烧工况与纯煤粉工况的温度变化趋势基本一致,且掺混比越大,炉膛最高温度和出口温度越低;掺混热解气替代部分煤粉,能有效降低炉膛出口污染物NO_(x)的排放量。随着掺混比增加,炉膛出口处NO_(x)含量分别是384.8,327.8,292.3,250.7 mg/Nm^(3);掺混热解气对烟气停留时间影响不大,能在一定程度上提高煤粉燃尽率。

In order to study the co-firing characteristics of pulverized coal and pyrolysis gas of organic solid waste,based on a 300 MW tangentially fired boiler,a pulverized coal blended pyrolysis gas model was built,and the influence of pyrolysis gas with a blending ratio of 10%,20%and 30%on the furnace velocity field,temperature field and combustion product emissions are investigated.The results show that the mixed combustion of pyrolysis gas and pulverized coal with a blending ratio of less than 30%has no significant disturbance to the overall velocity field in the furnace,and the flow field is well distributed.The temperature change trends of the blending conditions and the pure pulverized coal conditions are basically the same.And the greater the mixing ratio,the lower the maximum furnace temperature and outlet temperature.The blending of pyrolysis gas to replace part of the pulverized coal can effectively reduce the NO_(x)emission of the furnace outlet pollutant.With the increase of the mixing ratio,the NO_(x)content at the outlet of the furnace is 384.8,327.8,292.3 mg/Nm^(3)and 250.7 mg/Nm^(3).The mixing of pyrolysis gas has little effect on the residence time of flue gas but can increase the burnout rate of pulverized coal.