声波与相变联合作用下细颗粒脱除的实验研究

Experimental Study on Removal of Fine Particles Under the Combined Effect of Acoustic and Vapor Condensation

基于声波和相变耦合强化细颗粒长大机制,建立了声波与蒸汽相变联合作用下细颗粒物长大脱除的实验装置,并对细颗粒在不同外加条件下的脱除特性进行实验研究,探讨不同操作条件对细颗粒脱除效率的影响。结果表明：在2 000 Hz和150 dB的声波单独作用下,细颗粒的分级脱除效率较低在10%～23%左右;在过饱和度S=1.2的蒸汽环境中,细颗粒的分级脱除效率略高于声波单独作用的脱除效率;在声波和蒸汽相变联合作用下,细颗粒的分级脱除效率均得到大幅提高,分级脱除效率达到了53%～80%。相变单独作用时,在过饱和度较低时,细颗粒无凝结长大,因此脱除效率很低,脱除效率几乎不随过饱和度的增大而改变,但当过饱和度增到1.0后,细颗粒的脱除效率则随过饱和度的提高而迅速增大。在声波与相变联合作用下,细颗粒的脱除效率随过饱和度的增大而增加,当过饱和度增大到一定程度时,脱除效率出现大幅的提高,过饱和度从1.0增大到1.2,脱除效率从40%左右提高到80%。实验结果表明声波与相变联合作用可有效提高燃煤细颗粒的脱除效果。

Based on the mechanism of particle growth enhanced by acoustic wave combined vapor condensation, an experimental system was setup to investigate the removal of fine particles using the combined of acoustic and vapor condensation. The influence of operating parameters on fine particles removal efficiency was demonstrated under different conditions. The results show that particle staged removal efficiency is quite low at about 10% to 23% under the sound pressure level of 150 dB and frequency of 2 000 Hz. The removal efficiency seems a little higher by vapor condensation with supersaturation degree of 1.2 than acoustic agglomeration. However, the removal efficiency can be significantly promoted under the combined effect of acoustic and vapor condensation, which staged removal efficiency attains to 53%～80%. Fine particle can not be enlarged by vapor condensation in a low supersaturation degree and the removal efficiency is very low and independence of the supersaturation degree. But while the supersaturation degree is over 1.0, particle removal efficiency increases with the supersaturation degree rapidly. The removal efficiency increases with the supersaturation degree under the combined effect of acoustic and vapor condensation, especially, when the supersaturation degree reaches a critical value. The particle removal can be improved from 40% to 80% as the supersaturation degree increases from 1.0 to 1.2. It indicates that the combination of acoustic and vapor condensation can effectively improve the fine particle removal.