湍流团聚中不同尺度涡耦合促进燃煤细颗粒团聚与脱除研究

Promoting the Agglomeration and Removal of Coal-fired Fine Particles by Coupling of Different-scale Vortex in Turbulent Agglomeration

采用具有不同尺度结构湍流涡片的湍流团聚器,实验考察了颗粒物浓度、烟气温度与烟气流速等因素对燃煤细颗粒物在不同尺度涡耦合的湍流流场中团聚和脱除效果的影响。结果表明:随着烟气中细颗粒物浓度的提高,PM2.5与PM10的团聚效率分别提高约8.6%与8.8%,质量与数量脱除效率分别提高约8.3%与9.6%,但是细颗粒物浓度超过6×106个/cm^3后,颗粒物的团聚效率提升不明显;提高烟气温度对细颗粒物团聚与脱除效率提升作用不明显,当烟气温度由75℃提高至175℃时,PM2.5与PM10的团聚效率仅提高约2.7%与3.0%;提高烟气流速在一定范围内能够促进细颗粒物的团聚与脱除,但当烟气流速过大时,团聚和脱除效率下降,烟气流速在13 m/s时细颗粒物团聚与脱除效果最好,PM2.5与PM10的团聚效率分别为27.8%和24.2%。此外,通过对湍流团聚器中烟气流场以及不同粒径颗粒物之间的运动情况进行模拟计算,提出细颗粒物在不同尺度涡耦合的湍流流场中存在2种不同的团聚模式。

Turbulent vortex sheets of different structures and scales were coupled to make a turbulent agglomeration device.The influence of particle concentration,flue gas temperature and velocity on the agglomeration and removal effect of coal-fired fine particles in turbulent flow field with different-scale vortexes was investigated through experiments.The experimental results show that as the concentration of fine particles increase,the agglomeration efficiency of PM2.5 and PM10 increases by about 8.6%and 8.8%respectively.However,when the concentration exceed 6×1061/cm^3,the agglomeration efficiency of fine particles do not improve significantly.The increase of flue gas temperature has no obvious effect on the improvement of fine particle agglomeration and removal efficiency.When the flue gas temperature increase from 75℃to 175℃,the agglomeration efficiency of PM2.5 and PM10 only increases by about 2.7%and 3.0%.The increase of flue gas velocity can promote the agglomeration and removal of fine particles within a certain range,but when it is too high,the agglomeration and removal efficiency decreases.When the flue gas velocity is 13 m/s,the agglomeration and removal effect of fine particles is the best,and the agglomeration efficiency of PM2.5 and PM10 is 27.8%and 24.2%respectively.In addition,two kinds of agglomeration modes were proposed by simulating the flow field and the movement of fine particles in turbulent flow fields with different-scale vortexes.