在均匀磁场中分别对东胜、大同和徐州烟煤燃烧产生的3种飞灰细微粒子进行了聚并实验,研究了粒径、外磁场强度、粒子在磁场中停留时间以及粒子质量浓度对聚并脱除效率的影响。实验结果表明:在相同条件下,东胜烟煤飞灰粒子的聚并脱除效率最高,大同烟煤次之,徐州烟煤最小;在0.098~9.314μm粒径范围内,0.576~3.758μm粒径的3种飞灰粒子聚并脱除效率最高;聚并总脱除效率随磁感应强度、粒子在磁场中停留时间以及粒子质量浓度的增加而增大,粒子饱和磁化时,聚并总脱除效率达到最大值,不再随外磁场的增强而变化。采用二元碰撞聚并模型计算了粒子在均匀磁场中的聚并系数,在此基础上求解了粒子聚并动力学方程,预测了粒子的聚并脱除效率。数值模拟结果与实验结果相一致,在粒子质量浓度为40g·m^-3时,东胜烟煤、大同烟煤和徐州烟煤燃烧产生的3种飞灰粒子聚并总脱除效率分别为52.6%、43.1%、14.4%。
Aggregation experiments of three kinds of fine fly ash particles from Dongsheng, Datong and Xuzhou bituminous coal combustion were conducted in a uniform magnetic field.The influence of particle size, magnetic flux density, particle residence time and mass concentration on the particle removal rate was examined. Experimental results show that the removal rate of particles from Dongsheng bituminous coal combustion is higher than that for Datong and Xuzhou, and it is highest for the particle whose size is from 0.5761.tm to 3.7581.tm in the size range of 0.098~9.314μm. The total particle removal rate increases with the magnetic flux density, the residence time in the magnetic field and the mass concentration, and it reaches the maximum while particle magnetization is saturated. Based on the particles aggregation coefficient calculated by the binary collision-aggregation model, the total particle removal rate was simulated by solving the particle General Dynamic Equation. Numerical simulation results are in good agreement with the experimental data, and while particle mass concentration is 40g·m^-3, total removal rate of three kinds of fly ash particle is 52.6%, 43.1% and 14.4%, respectively.