燃煤细颗粒在过饱和氛围下声波团聚脱除的实验研究

摘要

An experimental installation was set up for investigating experimentally agglomeration removal of dust particles under various steam super-saturation degrees by using acoustic wave. The results show that the acoustic wave entrainment coefficient for these fine particles goes up with increase of the super-saturation degree, leading to improvement of the removal efficiencies. When the super-saturation degree is below 1.0,the total removal efficiency of dust particles has almost no increase with it, and is quite low, about 10%. However, when the super-saturation degree is bigger than 1.0, the total efficiency can be promoted and goes up rapidly with the increase of super-saturation degree. For example, when the super-saturation degree increases from 1.0 to 1.5, the removal efficiency rises about 50%. The removal efficiency of dust particles increases also with rising sound pressure level. Even if at high sound pressure steam condensational growth can not occur yet at 0.3 of low steam super-saturation degree, hence, only low removal efficiency, less than 20%, is observed. But at 1.2 of high steam super-saturation degree, the removal efficiency can be significantly improved, for example at 130dB of lower sound pressure level, about 70% high efficiency can be obtained. These facts indicate that removal of dust particles can be effectively improved if acoustic wave is used, i.e. their agglomeration with steam can be enlarged.%在不同过饱和氛围下，建立了燃煤细颗粒在声波场中团聚长大脱除的实验装置，对细颗粒物在声波场和不同过饱和氛围下的团聚长大脱除特性进行了实验研究。结果表明：细颗粒在声波场中的夹带系数随过饱和度的增大而增加，相应的脱除效率也有所提高；在过饱和度低于1.0时，细颗粒的总脱除效率很低(约为10%)，且几乎不随过饱和度的增大而增加，而当过饱和度大于1.0后，细颗粒的脱除效率随过饱和度的增大而迅速提高，过饱和度从1.0增大到1.5，相应的脱除效率提高了近50%。细颗粒的脱除效率随声压级的增大而提高，在过饱和度为0.3时，细颗粒无法发生凝结长大，总脱除效率很低，低于20%。但当过饱和度达到1.2，细颗粒的脱除效率得到了大幅提升，声压级在130dB时，细颗粒的脱除效率达到了70％左右，表明在低声压级的情况下，利用蒸汽相变可有效提高细颗粒在声波场中的团聚脱除效率。